Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * linux/mm/swapfile.c |
| 3 | * |
| 4 | * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds |
| 5 | * Swap reorganised 29.12.95, Stephen Tweedie |
| 6 | */ |
| 7 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 8 | #include <linux/mm.h> |
| 9 | #include <linux/hugetlb.h> |
| 10 | #include <linux/mman.h> |
| 11 | #include <linux/slab.h> |
| 12 | #include <linux/kernel_stat.h> |
| 13 | #include <linux/swap.h> |
| 14 | #include <linux/vmalloc.h> |
| 15 | #include <linux/pagemap.h> |
| 16 | #include <linux/namei.h> |
Hugh Dickins | 072441e | 2011-06-27 16:18:02 -0700 | [diff] [blame] | 17 | #include <linux/shmem_fs.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 18 | #include <linux/blkdev.h> |
Hugh Dickins | 20137a4 | 2009-01-06 14:39:54 -0800 | [diff] [blame] | 19 | #include <linux/random.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 20 | #include <linux/writeback.h> |
| 21 | #include <linux/proc_fs.h> |
| 22 | #include <linux/seq_file.h> |
| 23 | #include <linux/init.h> |
Hugh Dickins | 5ad6468 | 2009-12-14 17:59:24 -0800 | [diff] [blame] | 24 | #include <linux/ksm.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 25 | #include <linux/rmap.h> |
| 26 | #include <linux/security.h> |
| 27 | #include <linux/backing-dev.h> |
Ingo Molnar | fc0abb1 | 2006-01-18 17:42:33 -0800 | [diff] [blame] | 28 | #include <linux/mutex.h> |
Randy.Dunlap | c59ede7 | 2006-01-11 12:17:46 -0800 | [diff] [blame] | 29 | #include <linux/capability.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 30 | #include <linux/syscalls.h> |
Balbir Singh | 8a9f3cc | 2008-02-07 00:13:53 -0800 | [diff] [blame] | 31 | #include <linux/memcontrol.h> |
Kay Sievers | 66d7dd5 | 2010-10-26 14:22:06 -0700 | [diff] [blame] | 32 | #include <linux/poll.h> |
David Rientjes | 72788c3 | 2011-05-24 17:11:40 -0700 | [diff] [blame] | 33 | #include <linux/oom.h> |
Dan Magenheimer | 38b5faf | 2012-04-09 17:08:06 -0600 | [diff] [blame] | 34 | #include <linux/frontswap.h> |
| 35 | #include <linux/swapfile.h> |
Mel Gorman | f981c59 | 2012-07-31 16:44:47 -0700 | [diff] [blame] | 36 | #include <linux/export.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 37 | |
| 38 | #include <asm/pgtable.h> |
| 39 | #include <asm/tlbflush.h> |
| 40 | #include <linux/swapops.h> |
Johannes Weiner | 5d1ea48 | 2014-12-10 15:44:55 -0800 | [diff] [blame] | 41 | #include <linux/swap_cgroup.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 42 | |
Hugh Dickins | 570a335b | 2009-12-14 17:58:46 -0800 | [diff] [blame] | 43 | static bool swap_count_continued(struct swap_info_struct *, pgoff_t, |
| 44 | unsigned char); |
| 45 | static void free_swap_count_continuations(struct swap_info_struct *); |
Lee Schermerhorn | d4906e1 | 2009-12-14 17:58:49 -0800 | [diff] [blame] | 46 | static sector_t map_swap_entry(swp_entry_t, struct block_device**); |
Hugh Dickins | 570a335b | 2009-12-14 17:58:46 -0800 | [diff] [blame] | 47 | |
Dan Magenheimer | 38b5faf | 2012-04-09 17:08:06 -0600 | [diff] [blame] | 48 | DEFINE_SPINLOCK(swap_lock); |
Adrian Bunk | 7c363b8 | 2008-07-25 19:46:24 -0700 | [diff] [blame] | 49 | static unsigned int nr_swapfiles; |
Shaohua Li | ec8acf2 | 2013-02-22 16:34:38 -0800 | [diff] [blame] | 50 | atomic_long_t nr_swap_pages; |
| 51 | /* protected with swap_lock. reading in vm_swap_full() doesn't need lock */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 52 | long total_swap_pages; |
Hugh Dickins | 78ecba0 | 2008-07-23 21:28:23 -0700 | [diff] [blame] | 53 | static int least_priority; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 54 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 55 | static const char Bad_file[] = "Bad swap file entry "; |
| 56 | static const char Unused_file[] = "Unused swap file entry "; |
| 57 | static const char Bad_offset[] = "Bad swap offset entry "; |
| 58 | static const char Unused_offset[] = "Unused swap offset entry "; |
| 59 | |
Dan Streetman | adfab83 | 2014-06-04 16:09:53 -0700 | [diff] [blame] | 60 | /* |
| 61 | * all active swap_info_structs |
| 62 | * protected with swap_lock, and ordered by priority. |
| 63 | */ |
Dan Streetman | 18ab4d4 | 2014-06-04 16:09:59 -0700 | [diff] [blame] | 64 | PLIST_HEAD(swap_active_head); |
| 65 | |
| 66 | /* |
| 67 | * all available (active, not full) swap_info_structs |
| 68 | * protected with swap_avail_lock, ordered by priority. |
| 69 | * This is used by get_swap_page() instead of swap_active_head |
| 70 | * because swap_active_head includes all swap_info_structs, |
| 71 | * but get_swap_page() doesn't need to look at full ones. |
| 72 | * This uses its own lock instead of swap_lock because when a |
| 73 | * swap_info_struct changes between not-full/full, it needs to |
| 74 | * add/remove itself to/from this list, but the swap_info_struct->lock |
| 75 | * is held and the locking order requires swap_lock to be taken |
| 76 | * before any swap_info_struct->lock. |
| 77 | */ |
| 78 | static PLIST_HEAD(swap_avail_head); |
| 79 | static DEFINE_SPINLOCK(swap_avail_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 80 | |
Dan Magenheimer | 38b5faf | 2012-04-09 17:08:06 -0600 | [diff] [blame] | 81 | struct swap_info_struct *swap_info[MAX_SWAPFILES]; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 82 | |
Ingo Molnar | fc0abb1 | 2006-01-18 17:42:33 -0800 | [diff] [blame] | 83 | static DEFINE_MUTEX(swapon_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 84 | |
Kay Sievers | 66d7dd5 | 2010-10-26 14:22:06 -0700 | [diff] [blame] | 85 | static DECLARE_WAIT_QUEUE_HEAD(proc_poll_wait); |
| 86 | /* Activity counter to indicate that a swapon or swapoff has occurred */ |
| 87 | static atomic_t proc_poll_event = ATOMIC_INIT(0); |
| 88 | |
Hugh Dickins | 8d69aae | 2009-12-14 17:58:45 -0800 | [diff] [blame] | 89 | static inline unsigned char swap_count(unsigned char ent) |
KAMEZAWA Hiroyuki | 355cfa7 | 2009-06-16 15:32:53 -0700 | [diff] [blame] | 90 | { |
Hugh Dickins | 570a335b | 2009-12-14 17:58:46 -0800 | [diff] [blame] | 91 | return ent & ~SWAP_HAS_CACHE; /* may include SWAP_HAS_CONT flag */ |
KAMEZAWA Hiroyuki | 355cfa7 | 2009-06-16 15:32:53 -0700 | [diff] [blame] | 92 | } |
| 93 | |
Hugh Dickins | efa90a9 | 2009-12-14 17:58:41 -0800 | [diff] [blame] | 94 | /* returns 1 if swap entry is freed */ |
KAMEZAWA Hiroyuki | c9e4441 | 2009-06-16 15:32:54 -0700 | [diff] [blame] | 95 | static int |
| 96 | __try_to_reclaim_swap(struct swap_info_struct *si, unsigned long offset) |
| 97 | { |
Hugh Dickins | efa90a9 | 2009-12-14 17:58:41 -0800 | [diff] [blame] | 98 | swp_entry_t entry = swp_entry(si->type, offset); |
KAMEZAWA Hiroyuki | c9e4441 | 2009-06-16 15:32:54 -0700 | [diff] [blame] | 99 | struct page *page; |
| 100 | int ret = 0; |
| 101 | |
Shaohua Li | 33806f0 | 2013-02-22 16:34:37 -0800 | [diff] [blame] | 102 | page = find_get_page(swap_address_space(entry), entry.val); |
KAMEZAWA Hiroyuki | c9e4441 | 2009-06-16 15:32:54 -0700 | [diff] [blame] | 103 | if (!page) |
| 104 | return 0; |
| 105 | /* |
| 106 | * This function is called from scan_swap_map() and it's called |
| 107 | * by vmscan.c at reclaiming pages. So, we hold a lock on a page, here. |
| 108 | * We have to use trylock for avoiding deadlock. This is a special |
| 109 | * case and you should use try_to_free_swap() with explicit lock_page() |
| 110 | * in usual operations. |
| 111 | */ |
| 112 | if (trylock_page(page)) { |
| 113 | ret = try_to_free_swap(page); |
| 114 | unlock_page(page); |
| 115 | } |
| 116 | page_cache_release(page); |
| 117 | return ret; |
| 118 | } |
KAMEZAWA Hiroyuki | 355cfa7 | 2009-06-16 15:32:53 -0700 | [diff] [blame] | 119 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 120 | /* |
Hugh Dickins | 6a6ba83 | 2009-01-06 14:39:51 -0800 | [diff] [blame] | 121 | * swapon tell device that all the old swap contents can be discarded, |
| 122 | * to allow the swap device to optimize its wear-levelling. |
| 123 | */ |
| 124 | static int discard_swap(struct swap_info_struct *si) |
| 125 | { |
| 126 | struct swap_extent *se; |
Hugh Dickins | 9625a5f | 2009-12-14 17:58:42 -0800 | [diff] [blame] | 127 | sector_t start_block; |
| 128 | sector_t nr_blocks; |
Hugh Dickins | 6a6ba83 | 2009-01-06 14:39:51 -0800 | [diff] [blame] | 129 | int err = 0; |
| 130 | |
Hugh Dickins | 9625a5f | 2009-12-14 17:58:42 -0800 | [diff] [blame] | 131 | /* Do not discard the swap header page! */ |
| 132 | se = &si->first_swap_extent; |
| 133 | start_block = (se->start_block + 1) << (PAGE_SHIFT - 9); |
| 134 | nr_blocks = ((sector_t)se->nr_pages - 1) << (PAGE_SHIFT - 9); |
| 135 | if (nr_blocks) { |
| 136 | err = blkdev_issue_discard(si->bdev, start_block, |
Christoph Hellwig | dd3932e | 2010-09-16 20:51:46 +0200 | [diff] [blame] | 137 | nr_blocks, GFP_KERNEL, 0); |
Hugh Dickins | 9625a5f | 2009-12-14 17:58:42 -0800 | [diff] [blame] | 138 | if (err) |
| 139 | return err; |
| 140 | cond_resched(); |
| 141 | } |
Hugh Dickins | 6a6ba83 | 2009-01-06 14:39:51 -0800 | [diff] [blame] | 142 | |
Hugh Dickins | 9625a5f | 2009-12-14 17:58:42 -0800 | [diff] [blame] | 143 | list_for_each_entry(se, &si->first_swap_extent.list, list) { |
| 144 | start_block = se->start_block << (PAGE_SHIFT - 9); |
| 145 | nr_blocks = (sector_t)se->nr_pages << (PAGE_SHIFT - 9); |
Hugh Dickins | 6a6ba83 | 2009-01-06 14:39:51 -0800 | [diff] [blame] | 146 | |
| 147 | err = blkdev_issue_discard(si->bdev, start_block, |
Christoph Hellwig | dd3932e | 2010-09-16 20:51:46 +0200 | [diff] [blame] | 148 | nr_blocks, GFP_KERNEL, 0); |
Hugh Dickins | 6a6ba83 | 2009-01-06 14:39:51 -0800 | [diff] [blame] | 149 | if (err) |
| 150 | break; |
| 151 | |
| 152 | cond_resched(); |
| 153 | } |
| 154 | return err; /* That will often be -EOPNOTSUPP */ |
| 155 | } |
| 156 | |
Hugh Dickins | 7992fde | 2009-01-06 14:39:53 -0800 | [diff] [blame] | 157 | /* |
| 158 | * swap allocation tell device that a cluster of swap can now be discarded, |
| 159 | * to allow the swap device to optimize its wear-levelling. |
| 160 | */ |
| 161 | static void discard_swap_cluster(struct swap_info_struct *si, |
| 162 | pgoff_t start_page, pgoff_t nr_pages) |
| 163 | { |
| 164 | struct swap_extent *se = si->curr_swap_extent; |
| 165 | int found_extent = 0; |
| 166 | |
| 167 | while (nr_pages) { |
| 168 | struct list_head *lh; |
| 169 | |
| 170 | if (se->start_page <= start_page && |
| 171 | start_page < se->start_page + se->nr_pages) { |
| 172 | pgoff_t offset = start_page - se->start_page; |
| 173 | sector_t start_block = se->start_block + offset; |
Hugh Dickins | 858a2990 | 2009-01-06 14:39:56 -0800 | [diff] [blame] | 174 | sector_t nr_blocks = se->nr_pages - offset; |
Hugh Dickins | 7992fde | 2009-01-06 14:39:53 -0800 | [diff] [blame] | 175 | |
| 176 | if (nr_blocks > nr_pages) |
| 177 | nr_blocks = nr_pages; |
| 178 | start_page += nr_blocks; |
| 179 | nr_pages -= nr_blocks; |
| 180 | |
| 181 | if (!found_extent++) |
| 182 | si->curr_swap_extent = se; |
| 183 | |
| 184 | start_block <<= PAGE_SHIFT - 9; |
| 185 | nr_blocks <<= PAGE_SHIFT - 9; |
| 186 | if (blkdev_issue_discard(si->bdev, start_block, |
Christoph Hellwig | dd3932e | 2010-09-16 20:51:46 +0200 | [diff] [blame] | 187 | nr_blocks, GFP_NOIO, 0)) |
Hugh Dickins | 7992fde | 2009-01-06 14:39:53 -0800 | [diff] [blame] | 188 | break; |
| 189 | } |
| 190 | |
| 191 | lh = se->list.next; |
Hugh Dickins | 7992fde | 2009-01-06 14:39:53 -0800 | [diff] [blame] | 192 | se = list_entry(lh, struct swap_extent, list); |
| 193 | } |
| 194 | } |
| 195 | |
Hugh Dickins | 048c27f | 2005-09-03 15:54:40 -0700 | [diff] [blame] | 196 | #define SWAPFILE_CLUSTER 256 |
| 197 | #define LATENCY_LIMIT 256 |
| 198 | |
Shaohua Li | 2a8f944 | 2013-09-11 14:20:28 -0700 | [diff] [blame] | 199 | static inline void cluster_set_flag(struct swap_cluster_info *info, |
| 200 | unsigned int flag) |
| 201 | { |
| 202 | info->flags = flag; |
| 203 | } |
| 204 | |
| 205 | static inline unsigned int cluster_count(struct swap_cluster_info *info) |
| 206 | { |
| 207 | return info->data; |
| 208 | } |
| 209 | |
| 210 | static inline void cluster_set_count(struct swap_cluster_info *info, |
| 211 | unsigned int c) |
| 212 | { |
| 213 | info->data = c; |
| 214 | } |
| 215 | |
| 216 | static inline void cluster_set_count_flag(struct swap_cluster_info *info, |
| 217 | unsigned int c, unsigned int f) |
| 218 | { |
| 219 | info->flags = f; |
| 220 | info->data = c; |
| 221 | } |
| 222 | |
| 223 | static inline unsigned int cluster_next(struct swap_cluster_info *info) |
| 224 | { |
| 225 | return info->data; |
| 226 | } |
| 227 | |
| 228 | static inline void cluster_set_next(struct swap_cluster_info *info, |
| 229 | unsigned int n) |
| 230 | { |
| 231 | info->data = n; |
| 232 | } |
| 233 | |
| 234 | static inline void cluster_set_next_flag(struct swap_cluster_info *info, |
| 235 | unsigned int n, unsigned int f) |
| 236 | { |
| 237 | info->flags = f; |
| 238 | info->data = n; |
| 239 | } |
| 240 | |
| 241 | static inline bool cluster_is_free(struct swap_cluster_info *info) |
| 242 | { |
| 243 | return info->flags & CLUSTER_FLAG_FREE; |
| 244 | } |
| 245 | |
| 246 | static inline bool cluster_is_null(struct swap_cluster_info *info) |
| 247 | { |
| 248 | return info->flags & CLUSTER_FLAG_NEXT_NULL; |
| 249 | } |
| 250 | |
| 251 | static inline void cluster_set_null(struct swap_cluster_info *info) |
| 252 | { |
| 253 | info->flags = CLUSTER_FLAG_NEXT_NULL; |
| 254 | info->data = 0; |
| 255 | } |
| 256 | |
Shaohua Li | 815c2c5 | 2013-09-11 14:20:30 -0700 | [diff] [blame] | 257 | /* Add a cluster to discard list and schedule it to do discard */ |
| 258 | static void swap_cluster_schedule_discard(struct swap_info_struct *si, |
| 259 | unsigned int idx) |
| 260 | { |
| 261 | /* |
| 262 | * If scan_swap_map() can't find a free cluster, it will check |
| 263 | * si->swap_map directly. To make sure the discarding cluster isn't |
| 264 | * taken by scan_swap_map(), mark the swap entries bad (occupied). It |
| 265 | * will be cleared after discard |
| 266 | */ |
| 267 | memset(si->swap_map + idx * SWAPFILE_CLUSTER, |
| 268 | SWAP_MAP_BAD, SWAPFILE_CLUSTER); |
| 269 | |
| 270 | if (cluster_is_null(&si->discard_cluster_head)) { |
| 271 | cluster_set_next_flag(&si->discard_cluster_head, |
| 272 | idx, 0); |
| 273 | cluster_set_next_flag(&si->discard_cluster_tail, |
| 274 | idx, 0); |
| 275 | } else { |
| 276 | unsigned int tail = cluster_next(&si->discard_cluster_tail); |
| 277 | cluster_set_next(&si->cluster_info[tail], idx); |
| 278 | cluster_set_next_flag(&si->discard_cluster_tail, |
| 279 | idx, 0); |
| 280 | } |
| 281 | |
| 282 | schedule_work(&si->discard_work); |
| 283 | } |
| 284 | |
| 285 | /* |
| 286 | * Doing discard actually. After a cluster discard is finished, the cluster |
| 287 | * will be added to free cluster list. caller should hold si->lock. |
| 288 | */ |
| 289 | static void swap_do_scheduled_discard(struct swap_info_struct *si) |
| 290 | { |
| 291 | struct swap_cluster_info *info; |
| 292 | unsigned int idx; |
| 293 | |
| 294 | info = si->cluster_info; |
| 295 | |
| 296 | while (!cluster_is_null(&si->discard_cluster_head)) { |
| 297 | idx = cluster_next(&si->discard_cluster_head); |
| 298 | |
| 299 | cluster_set_next_flag(&si->discard_cluster_head, |
| 300 | cluster_next(&info[idx]), 0); |
| 301 | if (cluster_next(&si->discard_cluster_tail) == idx) { |
| 302 | cluster_set_null(&si->discard_cluster_head); |
| 303 | cluster_set_null(&si->discard_cluster_tail); |
| 304 | } |
| 305 | spin_unlock(&si->lock); |
| 306 | |
| 307 | discard_swap_cluster(si, idx * SWAPFILE_CLUSTER, |
| 308 | SWAPFILE_CLUSTER); |
| 309 | |
| 310 | spin_lock(&si->lock); |
| 311 | cluster_set_flag(&info[idx], CLUSTER_FLAG_FREE); |
| 312 | if (cluster_is_null(&si->free_cluster_head)) { |
| 313 | cluster_set_next_flag(&si->free_cluster_head, |
| 314 | idx, 0); |
| 315 | cluster_set_next_flag(&si->free_cluster_tail, |
| 316 | idx, 0); |
| 317 | } else { |
| 318 | unsigned int tail; |
| 319 | |
| 320 | tail = cluster_next(&si->free_cluster_tail); |
| 321 | cluster_set_next(&info[tail], idx); |
| 322 | cluster_set_next_flag(&si->free_cluster_tail, |
| 323 | idx, 0); |
| 324 | } |
| 325 | memset(si->swap_map + idx * SWAPFILE_CLUSTER, |
| 326 | 0, SWAPFILE_CLUSTER); |
| 327 | } |
| 328 | } |
| 329 | |
| 330 | static void swap_discard_work(struct work_struct *work) |
| 331 | { |
| 332 | struct swap_info_struct *si; |
| 333 | |
| 334 | si = container_of(work, struct swap_info_struct, discard_work); |
| 335 | |
| 336 | spin_lock(&si->lock); |
| 337 | swap_do_scheduled_discard(si); |
| 338 | spin_unlock(&si->lock); |
| 339 | } |
| 340 | |
Shaohua Li | 2a8f944 | 2013-09-11 14:20:28 -0700 | [diff] [blame] | 341 | /* |
| 342 | * The cluster corresponding to page_nr will be used. The cluster will be |
| 343 | * removed from free cluster list and its usage counter will be increased. |
| 344 | */ |
| 345 | static void inc_cluster_info_page(struct swap_info_struct *p, |
| 346 | struct swap_cluster_info *cluster_info, unsigned long page_nr) |
| 347 | { |
| 348 | unsigned long idx = page_nr / SWAPFILE_CLUSTER; |
| 349 | |
| 350 | if (!cluster_info) |
| 351 | return; |
| 352 | if (cluster_is_free(&cluster_info[idx])) { |
| 353 | VM_BUG_ON(cluster_next(&p->free_cluster_head) != idx); |
| 354 | cluster_set_next_flag(&p->free_cluster_head, |
| 355 | cluster_next(&cluster_info[idx]), 0); |
| 356 | if (cluster_next(&p->free_cluster_tail) == idx) { |
| 357 | cluster_set_null(&p->free_cluster_tail); |
| 358 | cluster_set_null(&p->free_cluster_head); |
| 359 | } |
| 360 | cluster_set_count_flag(&cluster_info[idx], 0, 0); |
| 361 | } |
| 362 | |
| 363 | VM_BUG_ON(cluster_count(&cluster_info[idx]) >= SWAPFILE_CLUSTER); |
| 364 | cluster_set_count(&cluster_info[idx], |
| 365 | cluster_count(&cluster_info[idx]) + 1); |
| 366 | } |
| 367 | |
| 368 | /* |
| 369 | * The cluster corresponding to page_nr decreases one usage. If the usage |
| 370 | * counter becomes 0, which means no page in the cluster is in using, we can |
| 371 | * optionally discard the cluster and add it to free cluster list. |
| 372 | */ |
| 373 | static void dec_cluster_info_page(struct swap_info_struct *p, |
| 374 | struct swap_cluster_info *cluster_info, unsigned long page_nr) |
| 375 | { |
| 376 | unsigned long idx = page_nr / SWAPFILE_CLUSTER; |
| 377 | |
| 378 | if (!cluster_info) |
| 379 | return; |
| 380 | |
| 381 | VM_BUG_ON(cluster_count(&cluster_info[idx]) == 0); |
| 382 | cluster_set_count(&cluster_info[idx], |
| 383 | cluster_count(&cluster_info[idx]) - 1); |
| 384 | |
| 385 | if (cluster_count(&cluster_info[idx]) == 0) { |
Shaohua Li | 815c2c5 | 2013-09-11 14:20:30 -0700 | [diff] [blame] | 386 | /* |
| 387 | * If the swap is discardable, prepare discard the cluster |
| 388 | * instead of free it immediately. The cluster will be freed |
| 389 | * after discard. |
| 390 | */ |
Shaohua Li | edfe23d | 2013-09-11 14:20:31 -0700 | [diff] [blame] | 391 | if ((p->flags & (SWP_WRITEOK | SWP_PAGE_DISCARD)) == |
| 392 | (SWP_WRITEOK | SWP_PAGE_DISCARD)) { |
Shaohua Li | 815c2c5 | 2013-09-11 14:20:30 -0700 | [diff] [blame] | 393 | swap_cluster_schedule_discard(p, idx); |
| 394 | return; |
| 395 | } |
| 396 | |
Shaohua Li | 2a8f944 | 2013-09-11 14:20:28 -0700 | [diff] [blame] | 397 | cluster_set_flag(&cluster_info[idx], CLUSTER_FLAG_FREE); |
| 398 | if (cluster_is_null(&p->free_cluster_head)) { |
| 399 | cluster_set_next_flag(&p->free_cluster_head, idx, 0); |
| 400 | cluster_set_next_flag(&p->free_cluster_tail, idx, 0); |
| 401 | } else { |
| 402 | unsigned int tail = cluster_next(&p->free_cluster_tail); |
| 403 | cluster_set_next(&cluster_info[tail], idx); |
| 404 | cluster_set_next_flag(&p->free_cluster_tail, idx, 0); |
| 405 | } |
| 406 | } |
| 407 | } |
| 408 | |
| 409 | /* |
| 410 | * It's possible scan_swap_map() uses a free cluster in the middle of free |
| 411 | * cluster list. Avoiding such abuse to avoid list corruption. |
| 412 | */ |
Shaohua Li | ebc2a1a | 2013-09-11 14:20:32 -0700 | [diff] [blame] | 413 | static bool |
| 414 | scan_swap_map_ssd_cluster_conflict(struct swap_info_struct *si, |
Shaohua Li | 2a8f944 | 2013-09-11 14:20:28 -0700 | [diff] [blame] | 415 | unsigned long offset) |
| 416 | { |
Shaohua Li | ebc2a1a | 2013-09-11 14:20:32 -0700 | [diff] [blame] | 417 | struct percpu_cluster *percpu_cluster; |
| 418 | bool conflict; |
| 419 | |
Shaohua Li | 2a8f944 | 2013-09-11 14:20:28 -0700 | [diff] [blame] | 420 | offset /= SWAPFILE_CLUSTER; |
Shaohua Li | ebc2a1a | 2013-09-11 14:20:32 -0700 | [diff] [blame] | 421 | conflict = !cluster_is_null(&si->free_cluster_head) && |
Shaohua Li | 2a8f944 | 2013-09-11 14:20:28 -0700 | [diff] [blame] | 422 | offset != cluster_next(&si->free_cluster_head) && |
| 423 | cluster_is_free(&si->cluster_info[offset]); |
Shaohua Li | ebc2a1a | 2013-09-11 14:20:32 -0700 | [diff] [blame] | 424 | |
| 425 | if (!conflict) |
| 426 | return false; |
| 427 | |
| 428 | percpu_cluster = this_cpu_ptr(si->percpu_cluster); |
| 429 | cluster_set_null(&percpu_cluster->index); |
| 430 | return true; |
| 431 | } |
| 432 | |
| 433 | /* |
| 434 | * Try to get a swap entry from current cpu's swap entry pool (a cluster). This |
| 435 | * might involve allocating a new cluster for current CPU too. |
| 436 | */ |
| 437 | static void scan_swap_map_try_ssd_cluster(struct swap_info_struct *si, |
| 438 | unsigned long *offset, unsigned long *scan_base) |
| 439 | { |
| 440 | struct percpu_cluster *cluster; |
| 441 | bool found_free; |
| 442 | unsigned long tmp; |
| 443 | |
| 444 | new_cluster: |
| 445 | cluster = this_cpu_ptr(si->percpu_cluster); |
| 446 | if (cluster_is_null(&cluster->index)) { |
| 447 | if (!cluster_is_null(&si->free_cluster_head)) { |
| 448 | cluster->index = si->free_cluster_head; |
| 449 | cluster->next = cluster_next(&cluster->index) * |
| 450 | SWAPFILE_CLUSTER; |
| 451 | } else if (!cluster_is_null(&si->discard_cluster_head)) { |
| 452 | /* |
| 453 | * we don't have free cluster but have some clusters in |
| 454 | * discarding, do discard now and reclaim them |
| 455 | */ |
| 456 | swap_do_scheduled_discard(si); |
| 457 | *scan_base = *offset = si->cluster_next; |
| 458 | goto new_cluster; |
| 459 | } else |
| 460 | return; |
| 461 | } |
| 462 | |
| 463 | found_free = false; |
| 464 | |
| 465 | /* |
| 466 | * Other CPUs can use our cluster if they can't find a free cluster, |
| 467 | * check if there is still free entry in the cluster |
| 468 | */ |
| 469 | tmp = cluster->next; |
| 470 | while (tmp < si->max && tmp < (cluster_next(&cluster->index) + 1) * |
| 471 | SWAPFILE_CLUSTER) { |
| 472 | if (!si->swap_map[tmp]) { |
| 473 | found_free = true; |
| 474 | break; |
| 475 | } |
| 476 | tmp++; |
| 477 | } |
| 478 | if (!found_free) { |
| 479 | cluster_set_null(&cluster->index); |
| 480 | goto new_cluster; |
| 481 | } |
| 482 | cluster->next = tmp + 1; |
| 483 | *offset = tmp; |
| 484 | *scan_base = tmp; |
Shaohua Li | 2a8f944 | 2013-09-11 14:20:28 -0700 | [diff] [blame] | 485 | } |
| 486 | |
Cesar Eduardo Barros | 24b8ff7 | 2011-03-22 16:33:38 -0700 | [diff] [blame] | 487 | static unsigned long scan_swap_map(struct swap_info_struct *si, |
| 488 | unsigned char usage) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 489 | { |
Hugh Dickins | ebebbbe | 2009-01-06 14:39:50 -0800 | [diff] [blame] | 490 | unsigned long offset; |
Hugh Dickins | c60aa17 | 2009-01-06 14:39:55 -0800 | [diff] [blame] | 491 | unsigned long scan_base; |
Hugh Dickins | 7992fde | 2009-01-06 14:39:53 -0800 | [diff] [blame] | 492 | unsigned long last_in_cluster = 0; |
Hugh Dickins | 048c27f | 2005-09-03 15:54:40 -0700 | [diff] [blame] | 493 | int latency_ration = LATENCY_LIMIT; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 494 | |
Hugh Dickins | 886bb7e | 2009-01-06 14:39:48 -0800 | [diff] [blame] | 495 | /* |
Hugh Dickins | 7dfad41 | 2005-09-03 15:54:38 -0700 | [diff] [blame] | 496 | * We try to cluster swap pages by allocating them sequentially |
| 497 | * in swap. Once we've allocated SWAPFILE_CLUSTER pages this |
| 498 | * way, however, we resort to first-free allocation, starting |
| 499 | * a new cluster. This prevents us from scattering swap pages |
| 500 | * all over the entire swap partition, so that we reduce |
| 501 | * overall disk seek times between swap pages. -- sct |
| 502 | * But we do now try to find an empty cluster. -Andrea |
Hugh Dickins | c60aa17 | 2009-01-06 14:39:55 -0800 | [diff] [blame] | 503 | * And we let swap pages go all over an SSD partition. Hugh |
Hugh Dickins | 7dfad41 | 2005-09-03 15:54:38 -0700 | [diff] [blame] | 504 | */ |
| 505 | |
Hugh Dickins | 52b7efdb | 2005-09-03 15:54:39 -0700 | [diff] [blame] | 506 | si->flags += SWP_SCANNING; |
Hugh Dickins | c60aa17 | 2009-01-06 14:39:55 -0800 | [diff] [blame] | 507 | scan_base = offset = si->cluster_next; |
Hugh Dickins | ebebbbe | 2009-01-06 14:39:50 -0800 | [diff] [blame] | 508 | |
Shaohua Li | ebc2a1a | 2013-09-11 14:20:32 -0700 | [diff] [blame] | 509 | /* SSD algorithm */ |
| 510 | if (si->cluster_info) { |
| 511 | scan_swap_map_try_ssd_cluster(si, &offset, &scan_base); |
| 512 | goto checks; |
| 513 | } |
| 514 | |
Hugh Dickins | ebebbbe | 2009-01-06 14:39:50 -0800 | [diff] [blame] | 515 | if (unlikely(!si->cluster_nr--)) { |
| 516 | if (si->pages - si->inuse_pages < SWAPFILE_CLUSTER) { |
| 517 | si->cluster_nr = SWAPFILE_CLUSTER - 1; |
| 518 | goto checks; |
| 519 | } |
Shaohua Li | 2a8f944 | 2013-09-11 14:20:28 -0700 | [diff] [blame] | 520 | |
Shaohua Li | ec8acf2 | 2013-02-22 16:34:38 -0800 | [diff] [blame] | 521 | spin_unlock(&si->lock); |
Hugh Dickins | 7dfad41 | 2005-09-03 15:54:38 -0700 | [diff] [blame] | 522 | |
Hugh Dickins | c60aa17 | 2009-01-06 14:39:55 -0800 | [diff] [blame] | 523 | /* |
| 524 | * If seek is expensive, start searching for new cluster from |
| 525 | * start of partition, to minimize the span of allocated swap. |
Chen Yucong | 50088c4 | 2014-06-04 16:10:57 -0700 | [diff] [blame] | 526 | * If seek is cheap, that is the SWP_SOLIDSTATE si->cluster_info |
| 527 | * case, just handled by scan_swap_map_try_ssd_cluster() above. |
Hugh Dickins | c60aa17 | 2009-01-06 14:39:55 -0800 | [diff] [blame] | 528 | */ |
Chen Yucong | 50088c4 | 2014-06-04 16:10:57 -0700 | [diff] [blame] | 529 | scan_base = offset = si->lowest_bit; |
Hugh Dickins | 7dfad41 | 2005-09-03 15:54:38 -0700 | [diff] [blame] | 530 | last_in_cluster = offset + SWAPFILE_CLUSTER - 1; |
| 531 | |
| 532 | /* Locate the first empty (unaligned) cluster */ |
| 533 | for (; last_in_cluster <= si->highest_bit; offset++) { |
| 534 | if (si->swap_map[offset]) |
| 535 | last_in_cluster = offset + SWAPFILE_CLUSTER; |
| 536 | else if (offset == last_in_cluster) { |
Shaohua Li | ec8acf2 | 2013-02-22 16:34:38 -0800 | [diff] [blame] | 537 | spin_lock(&si->lock); |
Hugh Dickins | ebebbbe | 2009-01-06 14:39:50 -0800 | [diff] [blame] | 538 | offset -= SWAPFILE_CLUSTER - 1; |
| 539 | si->cluster_next = offset; |
| 540 | si->cluster_nr = SWAPFILE_CLUSTER - 1; |
| 541 | goto checks; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 542 | } |
Hugh Dickins | 048c27f | 2005-09-03 15:54:40 -0700 | [diff] [blame] | 543 | if (unlikely(--latency_ration < 0)) { |
| 544 | cond_resched(); |
| 545 | latency_ration = LATENCY_LIMIT; |
| 546 | } |
Hugh Dickins | 7dfad41 | 2005-09-03 15:54:38 -0700 | [diff] [blame] | 547 | } |
Hugh Dickins | ebebbbe | 2009-01-06 14:39:50 -0800 | [diff] [blame] | 548 | |
Hugh Dickins | c60aa17 | 2009-01-06 14:39:55 -0800 | [diff] [blame] | 549 | offset = scan_base; |
Shaohua Li | ec8acf2 | 2013-02-22 16:34:38 -0800 | [diff] [blame] | 550 | spin_lock(&si->lock); |
Hugh Dickins | ebebbbe | 2009-01-06 14:39:50 -0800 | [diff] [blame] | 551 | si->cluster_nr = SWAPFILE_CLUSTER - 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 552 | } |
Hugh Dickins | 7dfad41 | 2005-09-03 15:54:38 -0700 | [diff] [blame] | 553 | |
Hugh Dickins | ebebbbe | 2009-01-06 14:39:50 -0800 | [diff] [blame] | 554 | checks: |
Shaohua Li | ebc2a1a | 2013-09-11 14:20:32 -0700 | [diff] [blame] | 555 | if (si->cluster_info) { |
| 556 | while (scan_swap_map_ssd_cluster_conflict(si, offset)) |
| 557 | scan_swap_map_try_ssd_cluster(si, &offset, &scan_base); |
| 558 | } |
Hugh Dickins | ebebbbe | 2009-01-06 14:39:50 -0800 | [diff] [blame] | 559 | if (!(si->flags & SWP_WRITEOK)) |
Hugh Dickins | 52b7efdb | 2005-09-03 15:54:39 -0700 | [diff] [blame] | 560 | goto no_page; |
Hugh Dickins | 7dfad41 | 2005-09-03 15:54:38 -0700 | [diff] [blame] | 561 | if (!si->highest_bit) |
| 562 | goto no_page; |
Hugh Dickins | ebebbbe | 2009-01-06 14:39:50 -0800 | [diff] [blame] | 563 | if (offset > si->highest_bit) |
Hugh Dickins | c60aa17 | 2009-01-06 14:39:55 -0800 | [diff] [blame] | 564 | scan_base = offset = si->lowest_bit; |
KAMEZAWA Hiroyuki | c9e4441 | 2009-06-16 15:32:54 -0700 | [diff] [blame] | 565 | |
Hugh Dickins | b73d7fc | 2010-09-09 16:38:09 -0700 | [diff] [blame] | 566 | /* reuse swap entry of cache-only swap if not busy. */ |
| 567 | if (vm_swap_full() && si->swap_map[offset] == SWAP_HAS_CACHE) { |
KAMEZAWA Hiroyuki | c9e4441 | 2009-06-16 15:32:54 -0700 | [diff] [blame] | 568 | int swap_was_freed; |
Shaohua Li | ec8acf2 | 2013-02-22 16:34:38 -0800 | [diff] [blame] | 569 | spin_unlock(&si->lock); |
KAMEZAWA Hiroyuki | c9e4441 | 2009-06-16 15:32:54 -0700 | [diff] [blame] | 570 | swap_was_freed = __try_to_reclaim_swap(si, offset); |
Shaohua Li | ec8acf2 | 2013-02-22 16:34:38 -0800 | [diff] [blame] | 571 | spin_lock(&si->lock); |
KAMEZAWA Hiroyuki | c9e4441 | 2009-06-16 15:32:54 -0700 | [diff] [blame] | 572 | /* entry was freed successfully, try to use this again */ |
| 573 | if (swap_was_freed) |
| 574 | goto checks; |
| 575 | goto scan; /* check next one */ |
| 576 | } |
| 577 | |
Hugh Dickins | ebebbbe | 2009-01-06 14:39:50 -0800 | [diff] [blame] | 578 | if (si->swap_map[offset]) |
| 579 | goto scan; |
Hugh Dickins | 7dfad41 | 2005-09-03 15:54:38 -0700 | [diff] [blame] | 580 | |
Hugh Dickins | ebebbbe | 2009-01-06 14:39:50 -0800 | [diff] [blame] | 581 | if (offset == si->lowest_bit) |
| 582 | si->lowest_bit++; |
| 583 | if (offset == si->highest_bit) |
| 584 | si->highest_bit--; |
| 585 | si->inuse_pages++; |
| 586 | if (si->inuse_pages == si->pages) { |
| 587 | si->lowest_bit = si->max; |
| 588 | si->highest_bit = 0; |
Dan Streetman | 18ab4d4 | 2014-06-04 16:09:59 -0700 | [diff] [blame] | 589 | spin_lock(&swap_avail_lock); |
| 590 | plist_del(&si->avail_list, &swap_avail_head); |
| 591 | spin_unlock(&swap_avail_lock); |
Hugh Dickins | ebebbbe | 2009-01-06 14:39:50 -0800 | [diff] [blame] | 592 | } |
Hugh Dickins | 253d553 | 2009-12-14 17:58:44 -0800 | [diff] [blame] | 593 | si->swap_map[offset] = usage; |
Shaohua Li | 2a8f944 | 2013-09-11 14:20:28 -0700 | [diff] [blame] | 594 | inc_cluster_info_page(si, si->cluster_info, offset); |
Hugh Dickins | ebebbbe | 2009-01-06 14:39:50 -0800 | [diff] [blame] | 595 | si->cluster_next = offset + 1; |
| 596 | si->flags -= SWP_SCANNING; |
Hugh Dickins | 7992fde | 2009-01-06 14:39:53 -0800 | [diff] [blame] | 597 | |
Hugh Dickins | ebebbbe | 2009-01-06 14:39:50 -0800 | [diff] [blame] | 598 | return offset; |
| 599 | |
| 600 | scan: |
Shaohua Li | ec8acf2 | 2013-02-22 16:34:38 -0800 | [diff] [blame] | 601 | spin_unlock(&si->lock); |
Hugh Dickins | 7dfad41 | 2005-09-03 15:54:38 -0700 | [diff] [blame] | 602 | while (++offset <= si->highest_bit) { |
Hugh Dickins | 52b7efdb | 2005-09-03 15:54:39 -0700 | [diff] [blame] | 603 | if (!si->swap_map[offset]) { |
Shaohua Li | ec8acf2 | 2013-02-22 16:34:38 -0800 | [diff] [blame] | 604 | spin_lock(&si->lock); |
Hugh Dickins | 52b7efdb | 2005-09-03 15:54:39 -0700 | [diff] [blame] | 605 | goto checks; |
| 606 | } |
KAMEZAWA Hiroyuki | c9e4441 | 2009-06-16 15:32:54 -0700 | [diff] [blame] | 607 | if (vm_swap_full() && si->swap_map[offset] == SWAP_HAS_CACHE) { |
Shaohua Li | ec8acf2 | 2013-02-22 16:34:38 -0800 | [diff] [blame] | 608 | spin_lock(&si->lock); |
KAMEZAWA Hiroyuki | c9e4441 | 2009-06-16 15:32:54 -0700 | [diff] [blame] | 609 | goto checks; |
| 610 | } |
Hugh Dickins | 048c27f | 2005-09-03 15:54:40 -0700 | [diff] [blame] | 611 | if (unlikely(--latency_ration < 0)) { |
| 612 | cond_resched(); |
| 613 | latency_ration = LATENCY_LIMIT; |
| 614 | } |
Hugh Dickins | 7dfad41 | 2005-09-03 15:54:38 -0700 | [diff] [blame] | 615 | } |
Hugh Dickins | c60aa17 | 2009-01-06 14:39:55 -0800 | [diff] [blame] | 616 | offset = si->lowest_bit; |
Jamie Liu | a599806 | 2014-01-23 15:53:40 -0800 | [diff] [blame] | 617 | while (offset < scan_base) { |
Hugh Dickins | c60aa17 | 2009-01-06 14:39:55 -0800 | [diff] [blame] | 618 | if (!si->swap_map[offset]) { |
Shaohua Li | ec8acf2 | 2013-02-22 16:34:38 -0800 | [diff] [blame] | 619 | spin_lock(&si->lock); |
Hugh Dickins | c60aa17 | 2009-01-06 14:39:55 -0800 | [diff] [blame] | 620 | goto checks; |
| 621 | } |
KAMEZAWA Hiroyuki | c9e4441 | 2009-06-16 15:32:54 -0700 | [diff] [blame] | 622 | if (vm_swap_full() && si->swap_map[offset] == SWAP_HAS_CACHE) { |
Shaohua Li | ec8acf2 | 2013-02-22 16:34:38 -0800 | [diff] [blame] | 623 | spin_lock(&si->lock); |
KAMEZAWA Hiroyuki | c9e4441 | 2009-06-16 15:32:54 -0700 | [diff] [blame] | 624 | goto checks; |
| 625 | } |
Hugh Dickins | c60aa17 | 2009-01-06 14:39:55 -0800 | [diff] [blame] | 626 | if (unlikely(--latency_ration < 0)) { |
| 627 | cond_resched(); |
| 628 | latency_ration = LATENCY_LIMIT; |
| 629 | } |
Jamie Liu | a599806 | 2014-01-23 15:53:40 -0800 | [diff] [blame] | 630 | offset++; |
Hugh Dickins | c60aa17 | 2009-01-06 14:39:55 -0800 | [diff] [blame] | 631 | } |
Shaohua Li | ec8acf2 | 2013-02-22 16:34:38 -0800 | [diff] [blame] | 632 | spin_lock(&si->lock); |
Hugh Dickins | 7dfad41 | 2005-09-03 15:54:38 -0700 | [diff] [blame] | 633 | |
| 634 | no_page: |
Hugh Dickins | 52b7efdb | 2005-09-03 15:54:39 -0700 | [diff] [blame] | 635 | si->flags -= SWP_SCANNING; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 636 | return 0; |
| 637 | } |
| 638 | |
| 639 | swp_entry_t get_swap_page(void) |
| 640 | { |
Dan Streetman | adfab83 | 2014-06-04 16:09:53 -0700 | [diff] [blame] | 641 | struct swap_info_struct *si, *next; |
Hugh Dickins | fb4f88d | 2005-09-03 15:54:37 -0700 | [diff] [blame] | 642 | pgoff_t offset; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 643 | |
Shaohua Li | ec8acf2 | 2013-02-22 16:34:38 -0800 | [diff] [blame] | 644 | if (atomic_long_read(&nr_swap_pages) <= 0) |
Hugh Dickins | fb4f88d | 2005-09-03 15:54:37 -0700 | [diff] [blame] | 645 | goto noswap; |
Shaohua Li | ec8acf2 | 2013-02-22 16:34:38 -0800 | [diff] [blame] | 646 | atomic_long_dec(&nr_swap_pages); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 647 | |
Dan Streetman | 18ab4d4 | 2014-06-04 16:09:59 -0700 | [diff] [blame] | 648 | spin_lock(&swap_avail_lock); |
| 649 | |
| 650 | start_over: |
| 651 | plist_for_each_entry_safe(si, next, &swap_avail_head, avail_list) { |
| 652 | /* requeue si to after same-priority siblings */ |
| 653 | plist_requeue(&si->avail_list, &swap_avail_head); |
| 654 | spin_unlock(&swap_avail_lock); |
Shaohua Li | ec8acf2 | 2013-02-22 16:34:38 -0800 | [diff] [blame] | 655 | spin_lock(&si->lock); |
Dan Streetman | adfab83 | 2014-06-04 16:09:53 -0700 | [diff] [blame] | 656 | if (!si->highest_bit || !(si->flags & SWP_WRITEOK)) { |
Dan Streetman | 18ab4d4 | 2014-06-04 16:09:59 -0700 | [diff] [blame] | 657 | spin_lock(&swap_avail_lock); |
| 658 | if (plist_node_empty(&si->avail_list)) { |
| 659 | spin_unlock(&si->lock); |
| 660 | goto nextsi; |
| 661 | } |
| 662 | WARN(!si->highest_bit, |
| 663 | "swap_info %d in list but !highest_bit\n", |
| 664 | si->type); |
| 665 | WARN(!(si->flags & SWP_WRITEOK), |
| 666 | "swap_info %d in list but !SWP_WRITEOK\n", |
| 667 | si->type); |
| 668 | plist_del(&si->avail_list, &swap_avail_head); |
Shaohua Li | ec8acf2 | 2013-02-22 16:34:38 -0800 | [diff] [blame] | 669 | spin_unlock(&si->lock); |
Dan Streetman | 18ab4d4 | 2014-06-04 16:09:59 -0700 | [diff] [blame] | 670 | goto nextsi; |
Shaohua Li | ec8acf2 | 2013-02-22 16:34:38 -0800 | [diff] [blame] | 671 | } |
Hugh Dickins | fb4f88d | 2005-09-03 15:54:37 -0700 | [diff] [blame] | 672 | |
KAMEZAWA Hiroyuki | 355cfa7 | 2009-06-16 15:32:53 -0700 | [diff] [blame] | 673 | /* This is called for allocating swap entry for cache */ |
Hugh Dickins | 253d553 | 2009-12-14 17:58:44 -0800 | [diff] [blame] | 674 | offset = scan_swap_map(si, SWAP_HAS_CACHE); |
Shaohua Li | ec8acf2 | 2013-02-22 16:34:38 -0800 | [diff] [blame] | 675 | spin_unlock(&si->lock); |
| 676 | if (offset) |
Dan Streetman | adfab83 | 2014-06-04 16:09:53 -0700 | [diff] [blame] | 677 | return swp_entry(si->type, offset); |
Dan Streetman | 18ab4d4 | 2014-06-04 16:09:59 -0700 | [diff] [blame] | 678 | pr_debug("scan_swap_map of si %d failed to find offset\n", |
| 679 | si->type); |
| 680 | spin_lock(&swap_avail_lock); |
| 681 | nextsi: |
Dan Streetman | adfab83 | 2014-06-04 16:09:53 -0700 | [diff] [blame] | 682 | /* |
| 683 | * if we got here, it's likely that si was almost full before, |
| 684 | * and since scan_swap_map() can drop the si->lock, multiple |
| 685 | * callers probably all tried to get a page from the same si |
Dan Streetman | 18ab4d4 | 2014-06-04 16:09:59 -0700 | [diff] [blame] | 686 | * and it filled up before we could get one; or, the si filled |
| 687 | * up between us dropping swap_avail_lock and taking si->lock. |
| 688 | * Since we dropped the swap_avail_lock, the swap_avail_head |
| 689 | * list may have been modified; so if next is still in the |
| 690 | * swap_avail_head list then try it, otherwise start over. |
Dan Streetman | adfab83 | 2014-06-04 16:09:53 -0700 | [diff] [blame] | 691 | */ |
Dan Streetman | 18ab4d4 | 2014-06-04 16:09:59 -0700 | [diff] [blame] | 692 | if (plist_node_empty(&next->avail_list)) |
| 693 | goto start_over; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 694 | } |
Hugh Dickins | fb4f88d | 2005-09-03 15:54:37 -0700 | [diff] [blame] | 695 | |
Dan Streetman | 18ab4d4 | 2014-06-04 16:09:59 -0700 | [diff] [blame] | 696 | spin_unlock(&swap_avail_lock); |
| 697 | |
Shaohua Li | ec8acf2 | 2013-02-22 16:34:38 -0800 | [diff] [blame] | 698 | atomic_long_inc(&nr_swap_pages); |
Hugh Dickins | fb4f88d | 2005-09-03 15:54:37 -0700 | [diff] [blame] | 699 | noswap: |
Hugh Dickins | fb4f88d | 2005-09-03 15:54:37 -0700 | [diff] [blame] | 700 | return (swp_entry_t) {0}; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 701 | } |
| 702 | |
Seth Jennings | 2de1a7e | 2013-11-12 15:07:46 -0800 | [diff] [blame] | 703 | /* The only caller of this function is now suspend routine */ |
Hugh Dickins | 910321e | 2010-09-09 16:38:07 -0700 | [diff] [blame] | 704 | swp_entry_t get_swap_page_of_type(int type) |
| 705 | { |
| 706 | struct swap_info_struct *si; |
| 707 | pgoff_t offset; |
| 708 | |
Hugh Dickins | 910321e | 2010-09-09 16:38:07 -0700 | [diff] [blame] | 709 | si = swap_info[type]; |
Shaohua Li | ec8acf2 | 2013-02-22 16:34:38 -0800 | [diff] [blame] | 710 | spin_lock(&si->lock); |
Hugh Dickins | 910321e | 2010-09-09 16:38:07 -0700 | [diff] [blame] | 711 | if (si && (si->flags & SWP_WRITEOK)) { |
Shaohua Li | ec8acf2 | 2013-02-22 16:34:38 -0800 | [diff] [blame] | 712 | atomic_long_dec(&nr_swap_pages); |
Hugh Dickins | 910321e | 2010-09-09 16:38:07 -0700 | [diff] [blame] | 713 | /* This is called for allocating swap entry, not cache */ |
| 714 | offset = scan_swap_map(si, 1); |
| 715 | if (offset) { |
Shaohua Li | ec8acf2 | 2013-02-22 16:34:38 -0800 | [diff] [blame] | 716 | spin_unlock(&si->lock); |
Hugh Dickins | 910321e | 2010-09-09 16:38:07 -0700 | [diff] [blame] | 717 | return swp_entry(type, offset); |
| 718 | } |
Shaohua Li | ec8acf2 | 2013-02-22 16:34:38 -0800 | [diff] [blame] | 719 | atomic_long_inc(&nr_swap_pages); |
Hugh Dickins | 910321e | 2010-09-09 16:38:07 -0700 | [diff] [blame] | 720 | } |
Shaohua Li | ec8acf2 | 2013-02-22 16:34:38 -0800 | [diff] [blame] | 721 | spin_unlock(&si->lock); |
Hugh Dickins | 910321e | 2010-09-09 16:38:07 -0700 | [diff] [blame] | 722 | return (swp_entry_t) {0}; |
| 723 | } |
| 724 | |
Hugh Dickins | 73c34b6 | 2009-12-14 17:58:43 -0800 | [diff] [blame] | 725 | static struct swap_info_struct *swap_info_get(swp_entry_t entry) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 726 | { |
Hugh Dickins | 73c34b6 | 2009-12-14 17:58:43 -0800 | [diff] [blame] | 727 | struct swap_info_struct *p; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 728 | unsigned long offset, type; |
| 729 | |
| 730 | if (!entry.val) |
| 731 | goto out; |
| 732 | type = swp_type(entry); |
| 733 | if (type >= nr_swapfiles) |
| 734 | goto bad_nofile; |
Hugh Dickins | efa90a9 | 2009-12-14 17:58:41 -0800 | [diff] [blame] | 735 | p = swap_info[type]; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 736 | if (!(p->flags & SWP_USED)) |
| 737 | goto bad_device; |
| 738 | offset = swp_offset(entry); |
| 739 | if (offset >= p->max) |
| 740 | goto bad_offset; |
| 741 | if (!p->swap_map[offset]) |
| 742 | goto bad_free; |
Shaohua Li | ec8acf2 | 2013-02-22 16:34:38 -0800 | [diff] [blame] | 743 | spin_lock(&p->lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 744 | return p; |
| 745 | |
| 746 | bad_free: |
Andrew Morton | 465c47f | 2013-09-11 14:20:17 -0700 | [diff] [blame] | 747 | pr_err("swap_free: %s%08lx\n", Unused_offset, entry.val); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 748 | goto out; |
| 749 | bad_offset: |
Andrew Morton | 465c47f | 2013-09-11 14:20:17 -0700 | [diff] [blame] | 750 | pr_err("swap_free: %s%08lx\n", Bad_offset, entry.val); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 751 | goto out; |
| 752 | bad_device: |
Andrew Morton | 465c47f | 2013-09-11 14:20:17 -0700 | [diff] [blame] | 753 | pr_err("swap_free: %s%08lx\n", Unused_file, entry.val); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 754 | goto out; |
| 755 | bad_nofile: |
Andrew Morton | 465c47f | 2013-09-11 14:20:17 -0700 | [diff] [blame] | 756 | pr_err("swap_free: %s%08lx\n", Bad_file, entry.val); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 757 | out: |
| 758 | return NULL; |
Hugh Dickins | 886bb7e | 2009-01-06 14:39:48 -0800 | [diff] [blame] | 759 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 760 | |
Hugh Dickins | 8d69aae | 2009-12-14 17:58:45 -0800 | [diff] [blame] | 761 | static unsigned char swap_entry_free(struct swap_info_struct *p, |
| 762 | swp_entry_t entry, unsigned char usage) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 763 | { |
Hugh Dickins | 253d553 | 2009-12-14 17:58:44 -0800 | [diff] [blame] | 764 | unsigned long offset = swp_offset(entry); |
Hugh Dickins | 8d69aae | 2009-12-14 17:58:45 -0800 | [diff] [blame] | 765 | unsigned char count; |
| 766 | unsigned char has_cache; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 767 | |
KAMEZAWA Hiroyuki | 355cfa7 | 2009-06-16 15:32:53 -0700 | [diff] [blame] | 768 | count = p->swap_map[offset]; |
Hugh Dickins | 253d553 | 2009-12-14 17:58:44 -0800 | [diff] [blame] | 769 | has_cache = count & SWAP_HAS_CACHE; |
| 770 | count &= ~SWAP_HAS_CACHE; |
| 771 | |
| 772 | if (usage == SWAP_HAS_CACHE) { |
| 773 | VM_BUG_ON(!has_cache); |
| 774 | has_cache = 0; |
Hugh Dickins | aaa4686 | 2009-12-14 17:58:47 -0800 | [diff] [blame] | 775 | } else if (count == SWAP_MAP_SHMEM) { |
| 776 | /* |
| 777 | * Or we could insist on shmem.c using a special |
| 778 | * swap_shmem_free() and free_shmem_swap_and_cache()... |
| 779 | */ |
| 780 | count = 0; |
Hugh Dickins | 570a335b | 2009-12-14 17:58:46 -0800 | [diff] [blame] | 781 | } else if ((count & ~COUNT_CONTINUED) <= SWAP_MAP_MAX) { |
| 782 | if (count == COUNT_CONTINUED) { |
| 783 | if (swap_count_continued(p, offset, count)) |
| 784 | count = SWAP_MAP_MAX | COUNT_CONTINUED; |
| 785 | else |
| 786 | count = SWAP_MAP_MAX; |
| 787 | } else |
| 788 | count--; |
| 789 | } |
Hugh Dickins | 253d553 | 2009-12-14 17:58:44 -0800 | [diff] [blame] | 790 | |
| 791 | if (!count) |
| 792 | mem_cgroup_uncharge_swap(entry); |
| 793 | |
| 794 | usage = count | has_cache; |
| 795 | p->swap_map[offset] = usage; |
| 796 | |
KAMEZAWA Hiroyuki | 355cfa7 | 2009-06-16 15:32:53 -0700 | [diff] [blame] | 797 | /* free if no reference */ |
Hugh Dickins | 253d553 | 2009-12-14 17:58:44 -0800 | [diff] [blame] | 798 | if (!usage) { |
Shaohua Li | 2a8f944 | 2013-09-11 14:20:28 -0700 | [diff] [blame] | 799 | dec_cluster_info_page(p, p->cluster_info, offset); |
KAMEZAWA Hiroyuki | 355cfa7 | 2009-06-16 15:32:53 -0700 | [diff] [blame] | 800 | if (offset < p->lowest_bit) |
| 801 | p->lowest_bit = offset; |
Dan Streetman | 18ab4d4 | 2014-06-04 16:09:59 -0700 | [diff] [blame] | 802 | if (offset > p->highest_bit) { |
| 803 | bool was_full = !p->highest_bit; |
KAMEZAWA Hiroyuki | 355cfa7 | 2009-06-16 15:32:53 -0700 | [diff] [blame] | 804 | p->highest_bit = offset; |
Dan Streetman | 18ab4d4 | 2014-06-04 16:09:59 -0700 | [diff] [blame] | 805 | if (was_full && (p->flags & SWP_WRITEOK)) { |
| 806 | spin_lock(&swap_avail_lock); |
| 807 | WARN_ON(!plist_node_empty(&p->avail_list)); |
| 808 | if (plist_node_empty(&p->avail_list)) |
| 809 | plist_add(&p->avail_list, |
| 810 | &swap_avail_head); |
| 811 | spin_unlock(&swap_avail_lock); |
| 812 | } |
| 813 | } |
Shaohua Li | ec8acf2 | 2013-02-22 16:34:38 -0800 | [diff] [blame] | 814 | atomic_long_inc(&nr_swap_pages); |
KAMEZAWA Hiroyuki | 355cfa7 | 2009-06-16 15:32:53 -0700 | [diff] [blame] | 815 | p->inuse_pages--; |
Dan Magenheimer | 38b5faf | 2012-04-09 17:08:06 -0600 | [diff] [blame] | 816 | frontswap_invalidate_page(p->type, offset); |
Mel Gorman | 7374492 | 2012-07-31 16:45:20 -0700 | [diff] [blame] | 817 | if (p->flags & SWP_BLKDEV) { |
| 818 | struct gendisk *disk = p->bdev->bd_disk; |
| 819 | if (disk->fops->swap_slot_free_notify) |
| 820 | disk->fops->swap_slot_free_notify(p->bdev, |
| 821 | offset); |
| 822 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 823 | } |
Hugh Dickins | 253d553 | 2009-12-14 17:58:44 -0800 | [diff] [blame] | 824 | |
| 825 | return usage; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 826 | } |
| 827 | |
| 828 | /* |
Seth Jennings | 2de1a7e | 2013-11-12 15:07:46 -0800 | [diff] [blame] | 829 | * Caller has made sure that the swap device corresponding to entry |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 830 | * is still around or has not been recycled. |
| 831 | */ |
| 832 | void swap_free(swp_entry_t entry) |
| 833 | { |
Hugh Dickins | 73c34b6 | 2009-12-14 17:58:43 -0800 | [diff] [blame] | 834 | struct swap_info_struct *p; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 835 | |
| 836 | p = swap_info_get(entry); |
| 837 | if (p) { |
Hugh Dickins | 253d553 | 2009-12-14 17:58:44 -0800 | [diff] [blame] | 838 | swap_entry_free(p, entry, 1); |
Shaohua Li | ec8acf2 | 2013-02-22 16:34:38 -0800 | [diff] [blame] | 839 | spin_unlock(&p->lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 840 | } |
| 841 | } |
| 842 | |
| 843 | /* |
KAMEZAWA Hiroyuki | cb4b86b | 2009-06-16 15:32:52 -0700 | [diff] [blame] | 844 | * Called after dropping swapcache to decrease refcnt to swap entries. |
| 845 | */ |
Johannes Weiner | 0a31bc9 | 2014-08-08 14:19:22 -0700 | [diff] [blame] | 846 | void swapcache_free(swp_entry_t entry) |
KAMEZAWA Hiroyuki | cb4b86b | 2009-06-16 15:32:52 -0700 | [diff] [blame] | 847 | { |
KAMEZAWA Hiroyuki | 355cfa7 | 2009-06-16 15:32:53 -0700 | [diff] [blame] | 848 | struct swap_info_struct *p; |
| 849 | |
KAMEZAWA Hiroyuki | 355cfa7 | 2009-06-16 15:32:53 -0700 | [diff] [blame] | 850 | p = swap_info_get(entry); |
| 851 | if (p) { |
Johannes Weiner | 0a31bc9 | 2014-08-08 14:19:22 -0700 | [diff] [blame] | 852 | swap_entry_free(p, entry, SWAP_HAS_CACHE); |
Shaohua Li | ec8acf2 | 2013-02-22 16:34:38 -0800 | [diff] [blame] | 853 | spin_unlock(&p->lock); |
KAMEZAWA Hiroyuki | 355cfa7 | 2009-06-16 15:32:53 -0700 | [diff] [blame] | 854 | } |
KAMEZAWA Hiroyuki | cb4b86b | 2009-06-16 15:32:52 -0700 | [diff] [blame] | 855 | } |
| 856 | |
| 857 | /* |
Hugh Dickins | c475a8a | 2005-06-21 17:15:12 -0700 | [diff] [blame] | 858 | * How many references to page are currently swapped out? |
Hugh Dickins | 570a335b | 2009-12-14 17:58:46 -0800 | [diff] [blame] | 859 | * This does not give an exact answer when swap count is continued, |
| 860 | * but does include the high COUNT_CONTINUED flag to allow for that. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 861 | */ |
Hugh Dickins | bde05d1 | 2012-05-29 15:06:38 -0700 | [diff] [blame] | 862 | int page_swapcount(struct page *page) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 863 | { |
Hugh Dickins | c475a8a | 2005-06-21 17:15:12 -0700 | [diff] [blame] | 864 | int count = 0; |
| 865 | struct swap_info_struct *p; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 866 | swp_entry_t entry; |
| 867 | |
Hugh Dickins | 4c21e2f | 2005-10-29 18:16:40 -0700 | [diff] [blame] | 868 | entry.val = page_private(page); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 869 | p = swap_info_get(entry); |
| 870 | if (p) { |
KAMEZAWA Hiroyuki | 355cfa7 | 2009-06-16 15:32:53 -0700 | [diff] [blame] | 871 | count = swap_count(p->swap_map[swp_offset(entry)]); |
Shaohua Li | ec8acf2 | 2013-02-22 16:34:38 -0800 | [diff] [blame] | 872 | spin_unlock(&p->lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 873 | } |
Hugh Dickins | c475a8a | 2005-06-21 17:15:12 -0700 | [diff] [blame] | 874 | return count; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 875 | } |
| 876 | |
| 877 | /* |
Hugh Dickins | 7b1fe59 | 2009-01-06 14:39:34 -0800 | [diff] [blame] | 878 | * We can write to an anon page without COW if there are no other references |
| 879 | * to it. And as a side-effect, free up its swap: because the old content |
| 880 | * on disk will never be read, and seeking back there to write new content |
| 881 | * later would only waste time away from clustering. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 882 | */ |
Hugh Dickins | 7b1fe59 | 2009-01-06 14:39:34 -0800 | [diff] [blame] | 883 | int reuse_swap_page(struct page *page) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 884 | { |
Hugh Dickins | c475a8a | 2005-06-21 17:15:12 -0700 | [diff] [blame] | 885 | int count; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 886 | |
Sasha Levin | 309381fea | 2014-01-23 15:52:54 -0800 | [diff] [blame] | 887 | VM_BUG_ON_PAGE(!PageLocked(page), page); |
Hugh Dickins | 5ad6468 | 2009-12-14 17:59:24 -0800 | [diff] [blame] | 888 | if (unlikely(PageKsm(page))) |
| 889 | return 0; |
Hugh Dickins | c475a8a | 2005-06-21 17:15:12 -0700 | [diff] [blame] | 890 | count = page_mapcount(page); |
Hugh Dickins | 7b1fe59 | 2009-01-06 14:39:34 -0800 | [diff] [blame] | 891 | if (count <= 1 && PageSwapCache(page)) { |
Hugh Dickins | c475a8a | 2005-06-21 17:15:12 -0700 | [diff] [blame] | 892 | count += page_swapcount(page); |
Hugh Dickins | 7b1fe59 | 2009-01-06 14:39:34 -0800 | [diff] [blame] | 893 | if (count == 1 && !PageWriteback(page)) { |
| 894 | delete_from_swap_cache(page); |
| 895 | SetPageDirty(page); |
| 896 | } |
| 897 | } |
Hugh Dickins | 5ad6468 | 2009-12-14 17:59:24 -0800 | [diff] [blame] | 898 | return count <= 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 899 | } |
| 900 | |
| 901 | /* |
Hugh Dickins | a2c43ee | 2009-01-06 14:39:36 -0800 | [diff] [blame] | 902 | * If swap is getting full, or if there are no more mappings of this page, |
| 903 | * then try_to_free_swap is called to free its swap space. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 904 | */ |
Hugh Dickins | a2c43ee | 2009-01-06 14:39:36 -0800 | [diff] [blame] | 905 | int try_to_free_swap(struct page *page) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 906 | { |
Sasha Levin | 309381fea | 2014-01-23 15:52:54 -0800 | [diff] [blame] | 907 | VM_BUG_ON_PAGE(!PageLocked(page), page); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 908 | |
| 909 | if (!PageSwapCache(page)) |
| 910 | return 0; |
| 911 | if (PageWriteback(page)) |
| 912 | return 0; |
Hugh Dickins | a2c43ee | 2009-01-06 14:39:36 -0800 | [diff] [blame] | 913 | if (page_swapcount(page)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 914 | return 0; |
| 915 | |
Hugh Dickins | b73d7fc | 2010-09-09 16:38:09 -0700 | [diff] [blame] | 916 | /* |
| 917 | * Once hibernation has begun to create its image of memory, |
| 918 | * there's a danger that one of the calls to try_to_free_swap() |
| 919 | * - most probably a call from __try_to_reclaim_swap() while |
| 920 | * hibernation is allocating its own swap pages for the image, |
| 921 | * but conceivably even a call from memory reclaim - will free |
| 922 | * the swap from a page which has already been recorded in the |
| 923 | * image as a clean swapcache page, and then reuse its swap for |
| 924 | * another page of the image. On waking from hibernation, the |
| 925 | * original page might be freed under memory pressure, then |
| 926 | * later read back in from swap, now with the wrong data. |
| 927 | * |
Seth Jennings | 2de1a7e | 2013-11-12 15:07:46 -0800 | [diff] [blame] | 928 | * Hibernation suspends storage while it is writing the image |
Mel Gorman | f90ac39 | 2012-01-10 15:07:15 -0800 | [diff] [blame] | 929 | * to disk so check that here. |
Hugh Dickins | b73d7fc | 2010-09-09 16:38:09 -0700 | [diff] [blame] | 930 | */ |
Mel Gorman | f90ac39 | 2012-01-10 15:07:15 -0800 | [diff] [blame] | 931 | if (pm_suspended_storage()) |
Hugh Dickins | b73d7fc | 2010-09-09 16:38:09 -0700 | [diff] [blame] | 932 | return 0; |
| 933 | |
Hugh Dickins | a2c43ee | 2009-01-06 14:39:36 -0800 | [diff] [blame] | 934 | delete_from_swap_cache(page); |
| 935 | SetPageDirty(page); |
| 936 | return 1; |
Rik van Riel | 68a22394 | 2008-10-18 20:26:23 -0700 | [diff] [blame] | 937 | } |
| 938 | |
| 939 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 940 | * Free the swap entry like above, but also try to |
| 941 | * free the page cache entry if it is the last user. |
| 942 | */ |
Hugh Dickins | 2509ef2 | 2009-01-06 14:40:10 -0800 | [diff] [blame] | 943 | int free_swap_and_cache(swp_entry_t entry) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 944 | { |
Hugh Dickins | 2509ef2 | 2009-01-06 14:40:10 -0800 | [diff] [blame] | 945 | struct swap_info_struct *p; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 946 | struct page *page = NULL; |
| 947 | |
Andi Kleen | a7420aa | 2009-09-16 11:50:05 +0200 | [diff] [blame] | 948 | if (non_swap_entry(entry)) |
Hugh Dickins | 2509ef2 | 2009-01-06 14:40:10 -0800 | [diff] [blame] | 949 | return 1; |
Christoph Lameter | 0697212 | 2006-06-23 02:03:35 -0700 | [diff] [blame] | 950 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 951 | p = swap_info_get(entry); |
| 952 | if (p) { |
Hugh Dickins | 253d553 | 2009-12-14 17:58:44 -0800 | [diff] [blame] | 953 | if (swap_entry_free(p, entry, 1) == SWAP_HAS_CACHE) { |
Shaohua Li | 33806f0 | 2013-02-22 16:34:37 -0800 | [diff] [blame] | 954 | page = find_get_page(swap_address_space(entry), |
| 955 | entry.val); |
Nick Piggin | 8413ac9 | 2008-10-18 20:26:59 -0700 | [diff] [blame] | 956 | if (page && !trylock_page(page)) { |
Nick Piggin | 93fac70 | 2006-03-31 02:29:56 -0800 | [diff] [blame] | 957 | page_cache_release(page); |
| 958 | page = NULL; |
| 959 | } |
| 960 | } |
Shaohua Li | ec8acf2 | 2013-02-22 16:34:38 -0800 | [diff] [blame] | 961 | spin_unlock(&p->lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 962 | } |
| 963 | if (page) { |
Hugh Dickins | a2c43ee | 2009-01-06 14:39:36 -0800 | [diff] [blame] | 964 | /* |
| 965 | * Not mapped elsewhere, or swap space full? Free it! |
| 966 | * Also recheck PageSwapCache now page is locked (above). |
| 967 | */ |
Nick Piggin | 93fac70 | 2006-03-31 02:29:56 -0800 | [diff] [blame] | 968 | if (PageSwapCache(page) && !PageWriteback(page) && |
Hugh Dickins | a2c43ee | 2009-01-06 14:39:36 -0800 | [diff] [blame] | 969 | (!page_mapped(page) || vm_swap_full())) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 970 | delete_from_swap_cache(page); |
| 971 | SetPageDirty(page); |
| 972 | } |
| 973 | unlock_page(page); |
| 974 | page_cache_release(page); |
| 975 | } |
Hugh Dickins | 2509ef2 | 2009-01-06 14:40:10 -0800 | [diff] [blame] | 976 | return p != NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 977 | } |
| 978 | |
Rafael J. Wysocki | b0cb1a1 | 2007-07-29 23:24:36 +0200 | [diff] [blame] | 979 | #ifdef CONFIG_HIBERNATION |
Rafael J. Wysocki | f577eb3 | 2006-03-23 02:59:59 -0800 | [diff] [blame] | 980 | /* |
Rafael J. Wysocki | 915bae9 | 2006-12-06 20:34:07 -0800 | [diff] [blame] | 981 | * Find the swap type that corresponds to given device (if any). |
Rafael J. Wysocki | f577eb3 | 2006-03-23 02:59:59 -0800 | [diff] [blame] | 982 | * |
Rafael J. Wysocki | 915bae9 | 2006-12-06 20:34:07 -0800 | [diff] [blame] | 983 | * @offset - number of the PAGE_SIZE-sized block of the device, starting |
| 984 | * from 0, in which the swap header is expected to be located. |
| 985 | * |
| 986 | * This is needed for the suspend to disk (aka swsusp). |
Rafael J. Wysocki | f577eb3 | 2006-03-23 02:59:59 -0800 | [diff] [blame] | 987 | */ |
Rafael J. Wysocki | 7bf2368 | 2007-01-05 16:36:28 -0800 | [diff] [blame] | 988 | int swap_type_of(dev_t device, sector_t offset, struct block_device **bdev_p) |
Rafael J. Wysocki | f577eb3 | 2006-03-23 02:59:59 -0800 | [diff] [blame] | 989 | { |
Rafael J. Wysocki | 915bae9 | 2006-12-06 20:34:07 -0800 | [diff] [blame] | 990 | struct block_device *bdev = NULL; |
Hugh Dickins | efa90a9 | 2009-12-14 17:58:41 -0800 | [diff] [blame] | 991 | int type; |
Rafael J. Wysocki | f577eb3 | 2006-03-23 02:59:59 -0800 | [diff] [blame] | 992 | |
Rafael J. Wysocki | 915bae9 | 2006-12-06 20:34:07 -0800 | [diff] [blame] | 993 | if (device) |
| 994 | bdev = bdget(device); |
| 995 | |
Rafael J. Wysocki | f577eb3 | 2006-03-23 02:59:59 -0800 | [diff] [blame] | 996 | spin_lock(&swap_lock); |
Hugh Dickins | efa90a9 | 2009-12-14 17:58:41 -0800 | [diff] [blame] | 997 | for (type = 0; type < nr_swapfiles; type++) { |
| 998 | struct swap_info_struct *sis = swap_info[type]; |
Rafael J. Wysocki | f577eb3 | 2006-03-23 02:59:59 -0800 | [diff] [blame] | 999 | |
Rafael J. Wysocki | 915bae9 | 2006-12-06 20:34:07 -0800 | [diff] [blame] | 1000 | if (!(sis->flags & SWP_WRITEOK)) |
Rafael J. Wysocki | f577eb3 | 2006-03-23 02:59:59 -0800 | [diff] [blame] | 1001 | continue; |
Rafael J. Wysocki | b6b5bce | 2006-08-27 01:23:25 -0700 | [diff] [blame] | 1002 | |
Rafael J. Wysocki | 915bae9 | 2006-12-06 20:34:07 -0800 | [diff] [blame] | 1003 | if (!bdev) { |
Rafael J. Wysocki | 7bf2368 | 2007-01-05 16:36:28 -0800 | [diff] [blame] | 1004 | if (bdev_p) |
Alan Jenkins | dddac6a | 2009-07-29 21:07:55 +0200 | [diff] [blame] | 1005 | *bdev_p = bdgrab(sis->bdev); |
Rafael J. Wysocki | 7bf2368 | 2007-01-05 16:36:28 -0800 | [diff] [blame] | 1006 | |
Rafael J. Wysocki | 6e1819d | 2006-03-23 03:00:03 -0800 | [diff] [blame] | 1007 | spin_unlock(&swap_lock); |
Hugh Dickins | efa90a9 | 2009-12-14 17:58:41 -0800 | [diff] [blame] | 1008 | return type; |
Rafael J. Wysocki | 6e1819d | 2006-03-23 03:00:03 -0800 | [diff] [blame] | 1009 | } |
Rafael J. Wysocki | 915bae9 | 2006-12-06 20:34:07 -0800 | [diff] [blame] | 1010 | if (bdev == sis->bdev) { |
Hugh Dickins | 9625a5f | 2009-12-14 17:58:42 -0800 | [diff] [blame] | 1011 | struct swap_extent *se = &sis->first_swap_extent; |
Rafael J. Wysocki | 915bae9 | 2006-12-06 20:34:07 -0800 | [diff] [blame] | 1012 | |
Rafael J. Wysocki | 915bae9 | 2006-12-06 20:34:07 -0800 | [diff] [blame] | 1013 | if (se->start_block == offset) { |
Rafael J. Wysocki | 7bf2368 | 2007-01-05 16:36:28 -0800 | [diff] [blame] | 1014 | if (bdev_p) |
Alan Jenkins | dddac6a | 2009-07-29 21:07:55 +0200 | [diff] [blame] | 1015 | *bdev_p = bdgrab(sis->bdev); |
Rafael J. Wysocki | 7bf2368 | 2007-01-05 16:36:28 -0800 | [diff] [blame] | 1016 | |
Rafael J. Wysocki | 915bae9 | 2006-12-06 20:34:07 -0800 | [diff] [blame] | 1017 | spin_unlock(&swap_lock); |
| 1018 | bdput(bdev); |
Hugh Dickins | efa90a9 | 2009-12-14 17:58:41 -0800 | [diff] [blame] | 1019 | return type; |
Rafael J. Wysocki | 915bae9 | 2006-12-06 20:34:07 -0800 | [diff] [blame] | 1020 | } |
Rafael J. Wysocki | f577eb3 | 2006-03-23 02:59:59 -0800 | [diff] [blame] | 1021 | } |
| 1022 | } |
| 1023 | spin_unlock(&swap_lock); |
Rafael J. Wysocki | 915bae9 | 2006-12-06 20:34:07 -0800 | [diff] [blame] | 1024 | if (bdev) |
| 1025 | bdput(bdev); |
| 1026 | |
Rafael J. Wysocki | f577eb3 | 2006-03-23 02:59:59 -0800 | [diff] [blame] | 1027 | return -ENODEV; |
| 1028 | } |
| 1029 | |
| 1030 | /* |
Hugh Dickins | 73c34b6 | 2009-12-14 17:58:43 -0800 | [diff] [blame] | 1031 | * Get the (PAGE_SIZE) block corresponding to given offset on the swapdev |
| 1032 | * corresponding to given index in swap_info (swap type). |
| 1033 | */ |
| 1034 | sector_t swapdev_block(int type, pgoff_t offset) |
| 1035 | { |
| 1036 | struct block_device *bdev; |
| 1037 | |
| 1038 | if ((unsigned int)type >= nr_swapfiles) |
| 1039 | return 0; |
| 1040 | if (!(swap_info[type]->flags & SWP_WRITEOK)) |
| 1041 | return 0; |
Lee Schermerhorn | d4906e1 | 2009-12-14 17:58:49 -0800 | [diff] [blame] | 1042 | return map_swap_entry(swp_entry(type, offset), &bdev); |
Hugh Dickins | 73c34b6 | 2009-12-14 17:58:43 -0800 | [diff] [blame] | 1043 | } |
| 1044 | |
| 1045 | /* |
Rafael J. Wysocki | f577eb3 | 2006-03-23 02:59:59 -0800 | [diff] [blame] | 1046 | * Return either the total number of swap pages of given type, or the number |
| 1047 | * of free pages of that type (depending on @free) |
| 1048 | * |
| 1049 | * This is needed for software suspend |
| 1050 | */ |
| 1051 | unsigned int count_swap_pages(int type, int free) |
| 1052 | { |
| 1053 | unsigned int n = 0; |
| 1054 | |
Hugh Dickins | efa90a9 | 2009-12-14 17:58:41 -0800 | [diff] [blame] | 1055 | spin_lock(&swap_lock); |
| 1056 | if ((unsigned int)type < nr_swapfiles) { |
| 1057 | struct swap_info_struct *sis = swap_info[type]; |
| 1058 | |
Shaohua Li | ec8acf2 | 2013-02-22 16:34:38 -0800 | [diff] [blame] | 1059 | spin_lock(&sis->lock); |
Hugh Dickins | efa90a9 | 2009-12-14 17:58:41 -0800 | [diff] [blame] | 1060 | if (sis->flags & SWP_WRITEOK) { |
| 1061 | n = sis->pages; |
Rafael J. Wysocki | f577eb3 | 2006-03-23 02:59:59 -0800 | [diff] [blame] | 1062 | if (free) |
Hugh Dickins | efa90a9 | 2009-12-14 17:58:41 -0800 | [diff] [blame] | 1063 | n -= sis->inuse_pages; |
Rafael J. Wysocki | f577eb3 | 2006-03-23 02:59:59 -0800 | [diff] [blame] | 1064 | } |
Shaohua Li | ec8acf2 | 2013-02-22 16:34:38 -0800 | [diff] [blame] | 1065 | spin_unlock(&sis->lock); |
Rafael J. Wysocki | f577eb3 | 2006-03-23 02:59:59 -0800 | [diff] [blame] | 1066 | } |
Hugh Dickins | efa90a9 | 2009-12-14 17:58:41 -0800 | [diff] [blame] | 1067 | spin_unlock(&swap_lock); |
Rafael J. Wysocki | f577eb3 | 2006-03-23 02:59:59 -0800 | [diff] [blame] | 1068 | return n; |
| 1069 | } |
Hugh Dickins | 73c34b6 | 2009-12-14 17:58:43 -0800 | [diff] [blame] | 1070 | #endif /* CONFIG_HIBERNATION */ |
Rafael J. Wysocki | f577eb3 | 2006-03-23 02:59:59 -0800 | [diff] [blame] | 1071 | |
Cyrill Gorcunov | 179ef71 | 2013-08-13 16:00:49 -0700 | [diff] [blame] | 1072 | static inline int maybe_same_pte(pte_t pte, pte_t swp_pte) |
| 1073 | { |
| 1074 | #ifdef CONFIG_MEM_SOFT_DIRTY |
| 1075 | /* |
| 1076 | * When pte keeps soft dirty bit the pte generated |
| 1077 | * from swap entry does not has it, still it's same |
| 1078 | * pte from logical point of view. |
| 1079 | */ |
| 1080 | pte_t swp_pte_dirty = pte_swp_mksoft_dirty(swp_pte); |
| 1081 | return pte_same(pte, swp_pte) || pte_same(pte, swp_pte_dirty); |
| 1082 | #else |
| 1083 | return pte_same(pte, swp_pte); |
| 1084 | #endif |
| 1085 | } |
| 1086 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1087 | /* |
Hugh Dickins | 72866f6 | 2005-10-29 18:15:55 -0700 | [diff] [blame] | 1088 | * No need to decide whether this PTE shares the swap entry with others, |
| 1089 | * just let do_wp_page work it out if a write is requested later - to |
| 1090 | * force COW, vm_page_prot omits write permission from any private vma. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1091 | */ |
Hugh Dickins | 044d66c | 2008-02-07 00:14:04 -0800 | [diff] [blame] | 1092 | static int unuse_pte(struct vm_area_struct *vma, pmd_t *pmd, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1093 | unsigned long addr, swp_entry_t entry, struct page *page) |
| 1094 | { |
Hugh Dickins | 9e16b7f | 2013-02-22 16:36:09 -0800 | [diff] [blame] | 1095 | struct page *swapcache; |
Johannes Weiner | 72835c8 | 2012-01-12 17:18:32 -0800 | [diff] [blame] | 1096 | struct mem_cgroup *memcg; |
Hugh Dickins | 044d66c | 2008-02-07 00:14:04 -0800 | [diff] [blame] | 1097 | spinlock_t *ptl; |
| 1098 | pte_t *pte; |
| 1099 | int ret = 1; |
| 1100 | |
Hugh Dickins | 9e16b7f | 2013-02-22 16:36:09 -0800 | [diff] [blame] | 1101 | swapcache = page; |
| 1102 | page = ksm_might_need_to_copy(page, vma, addr); |
| 1103 | if (unlikely(!page)) |
| 1104 | return -ENOMEM; |
| 1105 | |
Johannes Weiner | 00501b5 | 2014-08-08 14:19:20 -0700 | [diff] [blame] | 1106 | if (mem_cgroup_try_charge(page, vma->vm_mm, GFP_KERNEL, &memcg)) { |
Hugh Dickins | 044d66c | 2008-02-07 00:14:04 -0800 | [diff] [blame] | 1107 | ret = -ENOMEM; |
KAMEZAWA Hiroyuki | 85d9fc8 | 2009-01-29 14:25:13 -0800 | [diff] [blame] | 1108 | goto out_nolock; |
| 1109 | } |
Hugh Dickins | 044d66c | 2008-02-07 00:14:04 -0800 | [diff] [blame] | 1110 | |
| 1111 | pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl); |
Cyrill Gorcunov | 179ef71 | 2013-08-13 16:00:49 -0700 | [diff] [blame] | 1112 | if (unlikely(!maybe_same_pte(*pte, swp_entry_to_pte(entry)))) { |
Johannes Weiner | 00501b5 | 2014-08-08 14:19:20 -0700 | [diff] [blame] | 1113 | mem_cgroup_cancel_charge(page, memcg); |
Hugh Dickins | 044d66c | 2008-02-07 00:14:04 -0800 | [diff] [blame] | 1114 | ret = 0; |
| 1115 | goto out; |
| 1116 | } |
Balbir Singh | 8a9f3cc | 2008-02-07 00:13:53 -0800 | [diff] [blame] | 1117 | |
KAMEZAWA Hiroyuki | b084d43 | 2010-03-05 13:41:42 -0800 | [diff] [blame] | 1118 | dec_mm_counter(vma->vm_mm, MM_SWAPENTS); |
KAMEZAWA Hiroyuki | d559db0 | 2010-03-05 13:41:39 -0800 | [diff] [blame] | 1119 | inc_mm_counter(vma->vm_mm, MM_ANONPAGES); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1120 | get_page(page); |
| 1121 | set_pte_at(vma->vm_mm, addr, pte, |
| 1122 | pte_mkold(mk_pte(page, vma->vm_page_prot))); |
Johannes Weiner | 00501b5 | 2014-08-08 14:19:20 -0700 | [diff] [blame] | 1123 | if (page == swapcache) { |
Hugh Dickins | 9e16b7f | 2013-02-22 16:36:09 -0800 | [diff] [blame] | 1124 | page_add_anon_rmap(page, vma, addr); |
Johannes Weiner | 00501b5 | 2014-08-08 14:19:20 -0700 | [diff] [blame] | 1125 | mem_cgroup_commit_charge(page, memcg, true); |
| 1126 | } else { /* ksm created a completely new copy */ |
Hugh Dickins | 9e16b7f | 2013-02-22 16:36:09 -0800 | [diff] [blame] | 1127 | page_add_new_anon_rmap(page, vma, addr); |
Johannes Weiner | 00501b5 | 2014-08-08 14:19:20 -0700 | [diff] [blame] | 1128 | mem_cgroup_commit_charge(page, memcg, false); |
| 1129 | lru_cache_add_active_or_unevictable(page, vma); |
| 1130 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1131 | swap_free(entry); |
| 1132 | /* |
| 1133 | * Move the page to the active list so it is not |
| 1134 | * immediately swapped out again after swapon. |
| 1135 | */ |
| 1136 | activate_page(page); |
Hugh Dickins | 044d66c | 2008-02-07 00:14:04 -0800 | [diff] [blame] | 1137 | out: |
| 1138 | pte_unmap_unlock(pte, ptl); |
KAMEZAWA Hiroyuki | 85d9fc8 | 2009-01-29 14:25:13 -0800 | [diff] [blame] | 1139 | out_nolock: |
Hugh Dickins | 9e16b7f | 2013-02-22 16:36:09 -0800 | [diff] [blame] | 1140 | if (page != swapcache) { |
| 1141 | unlock_page(page); |
| 1142 | put_page(page); |
| 1143 | } |
Hugh Dickins | 044d66c | 2008-02-07 00:14:04 -0800 | [diff] [blame] | 1144 | return ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1145 | } |
| 1146 | |
| 1147 | static int unuse_pte_range(struct vm_area_struct *vma, pmd_t *pmd, |
| 1148 | unsigned long addr, unsigned long end, |
| 1149 | swp_entry_t entry, struct page *page) |
| 1150 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1151 | pte_t swp_pte = swp_entry_to_pte(entry); |
Hugh Dickins | 705e87c | 2005-10-29 18:16:27 -0700 | [diff] [blame] | 1152 | pte_t *pte; |
Balbir Singh | 8a9f3cc | 2008-02-07 00:13:53 -0800 | [diff] [blame] | 1153 | int ret = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1154 | |
Hugh Dickins | 044d66c | 2008-02-07 00:14:04 -0800 | [diff] [blame] | 1155 | /* |
| 1156 | * We don't actually need pte lock while scanning for swp_pte: since |
| 1157 | * we hold page lock and mmap_sem, swp_pte cannot be inserted into the |
| 1158 | * page table while we're scanning; though it could get zapped, and on |
| 1159 | * some architectures (e.g. x86_32 with PAE) we might catch a glimpse |
| 1160 | * of unmatched parts which look like swp_pte, so unuse_pte must |
| 1161 | * recheck under pte lock. Scanning without pte lock lets it be |
Seth Jennings | 2de1a7e | 2013-11-12 15:07:46 -0800 | [diff] [blame] | 1162 | * preemptable whenever CONFIG_PREEMPT but not CONFIG_HIGHPTE. |
Hugh Dickins | 044d66c | 2008-02-07 00:14:04 -0800 | [diff] [blame] | 1163 | */ |
| 1164 | pte = pte_offset_map(pmd, addr); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1165 | do { |
| 1166 | /* |
| 1167 | * swapoff spends a _lot_ of time in this loop! |
| 1168 | * Test inline before going to call unuse_pte. |
| 1169 | */ |
Cyrill Gorcunov | 179ef71 | 2013-08-13 16:00:49 -0700 | [diff] [blame] | 1170 | if (unlikely(maybe_same_pte(*pte, swp_pte))) { |
Hugh Dickins | 044d66c | 2008-02-07 00:14:04 -0800 | [diff] [blame] | 1171 | pte_unmap(pte); |
| 1172 | ret = unuse_pte(vma, pmd, addr, entry, page); |
| 1173 | if (ret) |
| 1174 | goto out; |
| 1175 | pte = pte_offset_map(pmd, addr); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1176 | } |
| 1177 | } while (pte++, addr += PAGE_SIZE, addr != end); |
Hugh Dickins | 044d66c | 2008-02-07 00:14:04 -0800 | [diff] [blame] | 1178 | pte_unmap(pte - 1); |
| 1179 | out: |
Balbir Singh | 8a9f3cc | 2008-02-07 00:13:53 -0800 | [diff] [blame] | 1180 | return ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1181 | } |
| 1182 | |
| 1183 | static inline int unuse_pmd_range(struct vm_area_struct *vma, pud_t *pud, |
| 1184 | unsigned long addr, unsigned long end, |
| 1185 | swp_entry_t entry, struct page *page) |
| 1186 | { |
| 1187 | pmd_t *pmd; |
| 1188 | unsigned long next; |
Balbir Singh | 8a9f3cc | 2008-02-07 00:13:53 -0800 | [diff] [blame] | 1189 | int ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1190 | |
| 1191 | pmd = pmd_offset(pud, addr); |
| 1192 | do { |
| 1193 | next = pmd_addr_end(addr, end); |
Andrea Arcangeli | 1a5a990 | 2012-03-21 16:33:42 -0700 | [diff] [blame] | 1194 | if (pmd_none_or_trans_huge_or_clear_bad(pmd)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1195 | continue; |
Balbir Singh | 8a9f3cc | 2008-02-07 00:13:53 -0800 | [diff] [blame] | 1196 | ret = unuse_pte_range(vma, pmd, addr, next, entry, page); |
| 1197 | if (ret) |
| 1198 | return ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1199 | } while (pmd++, addr = next, addr != end); |
| 1200 | return 0; |
| 1201 | } |
| 1202 | |
| 1203 | static inline int unuse_pud_range(struct vm_area_struct *vma, pgd_t *pgd, |
| 1204 | unsigned long addr, unsigned long end, |
| 1205 | swp_entry_t entry, struct page *page) |
| 1206 | { |
| 1207 | pud_t *pud; |
| 1208 | unsigned long next; |
Balbir Singh | 8a9f3cc | 2008-02-07 00:13:53 -0800 | [diff] [blame] | 1209 | int ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1210 | |
| 1211 | pud = pud_offset(pgd, addr); |
| 1212 | do { |
| 1213 | next = pud_addr_end(addr, end); |
| 1214 | if (pud_none_or_clear_bad(pud)) |
| 1215 | continue; |
Balbir Singh | 8a9f3cc | 2008-02-07 00:13:53 -0800 | [diff] [blame] | 1216 | ret = unuse_pmd_range(vma, pud, addr, next, entry, page); |
| 1217 | if (ret) |
| 1218 | return ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1219 | } while (pud++, addr = next, addr != end); |
| 1220 | return 0; |
| 1221 | } |
| 1222 | |
| 1223 | static int unuse_vma(struct vm_area_struct *vma, |
| 1224 | swp_entry_t entry, struct page *page) |
| 1225 | { |
| 1226 | pgd_t *pgd; |
| 1227 | unsigned long addr, end, next; |
Balbir Singh | 8a9f3cc | 2008-02-07 00:13:53 -0800 | [diff] [blame] | 1228 | int ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1229 | |
Hugh Dickins | 3ca7b3c | 2009-12-14 17:58:57 -0800 | [diff] [blame] | 1230 | if (page_anon_vma(page)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1231 | addr = page_address_in_vma(page, vma); |
| 1232 | if (addr == -EFAULT) |
| 1233 | return 0; |
| 1234 | else |
| 1235 | end = addr + PAGE_SIZE; |
| 1236 | } else { |
| 1237 | addr = vma->vm_start; |
| 1238 | end = vma->vm_end; |
| 1239 | } |
| 1240 | |
| 1241 | pgd = pgd_offset(vma->vm_mm, addr); |
| 1242 | do { |
| 1243 | next = pgd_addr_end(addr, end); |
| 1244 | if (pgd_none_or_clear_bad(pgd)) |
| 1245 | continue; |
Balbir Singh | 8a9f3cc | 2008-02-07 00:13:53 -0800 | [diff] [blame] | 1246 | ret = unuse_pud_range(vma, pgd, addr, next, entry, page); |
| 1247 | if (ret) |
| 1248 | return ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1249 | } while (pgd++, addr = next, addr != end); |
| 1250 | return 0; |
| 1251 | } |
| 1252 | |
| 1253 | static int unuse_mm(struct mm_struct *mm, |
| 1254 | swp_entry_t entry, struct page *page) |
| 1255 | { |
| 1256 | struct vm_area_struct *vma; |
Balbir Singh | 8a9f3cc | 2008-02-07 00:13:53 -0800 | [diff] [blame] | 1257 | int ret = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1258 | |
| 1259 | if (!down_read_trylock(&mm->mmap_sem)) { |
| 1260 | /* |
Fernando Luis Vazquez Cao | 7d03431 | 2008-07-29 22:33:41 -0700 | [diff] [blame] | 1261 | * Activate page so shrink_inactive_list is unlikely to unmap |
| 1262 | * its ptes while lock is dropped, so swapoff can make progress. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1263 | */ |
Hugh Dickins | c475a8a | 2005-06-21 17:15:12 -0700 | [diff] [blame] | 1264 | activate_page(page); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1265 | unlock_page(page); |
| 1266 | down_read(&mm->mmap_sem); |
| 1267 | lock_page(page); |
| 1268 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1269 | for (vma = mm->mmap; vma; vma = vma->vm_next) { |
Balbir Singh | 8a9f3cc | 2008-02-07 00:13:53 -0800 | [diff] [blame] | 1270 | if (vma->anon_vma && (ret = unuse_vma(vma, entry, page))) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1271 | break; |
| 1272 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1273 | up_read(&mm->mmap_sem); |
Balbir Singh | 8a9f3cc | 2008-02-07 00:13:53 -0800 | [diff] [blame] | 1274 | return (ret < 0)? ret: 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1275 | } |
| 1276 | |
| 1277 | /* |
Dan Magenheimer | 38b5faf | 2012-04-09 17:08:06 -0600 | [diff] [blame] | 1278 | * Scan swap_map (or frontswap_map if frontswap parameter is true) |
| 1279 | * from current position to next entry still in use. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1280 | * Recycle to start on reaching the end, returning 0 when empty. |
| 1281 | */ |
Hugh Dickins | 6eb396d | 2005-09-03 15:54:35 -0700 | [diff] [blame] | 1282 | static unsigned int find_next_to_unuse(struct swap_info_struct *si, |
Dan Magenheimer | 38b5faf | 2012-04-09 17:08:06 -0600 | [diff] [blame] | 1283 | unsigned int prev, bool frontswap) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1284 | { |
Hugh Dickins | 6eb396d | 2005-09-03 15:54:35 -0700 | [diff] [blame] | 1285 | unsigned int max = si->max; |
| 1286 | unsigned int i = prev; |
Hugh Dickins | 8d69aae | 2009-12-14 17:58:45 -0800 | [diff] [blame] | 1287 | unsigned char count; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1288 | |
| 1289 | /* |
Hugh Dickins | 5d337b9 | 2005-09-03 15:54:41 -0700 | [diff] [blame] | 1290 | * No need for swap_lock here: we're just looking |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1291 | * for whether an entry is in use, not modifying it; false |
| 1292 | * hits are okay, and sys_swapoff() has already prevented new |
Hugh Dickins | 5d337b9 | 2005-09-03 15:54:41 -0700 | [diff] [blame] | 1293 | * allocations from this area (while holding swap_lock). |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1294 | */ |
| 1295 | for (;;) { |
| 1296 | if (++i >= max) { |
| 1297 | if (!prev) { |
| 1298 | i = 0; |
| 1299 | break; |
| 1300 | } |
| 1301 | /* |
| 1302 | * No entries in use at top of swap_map, |
| 1303 | * loop back to start and recheck there. |
| 1304 | */ |
| 1305 | max = prev + 1; |
| 1306 | prev = 0; |
| 1307 | i = 1; |
| 1308 | } |
Dan Magenheimer | 38b5faf | 2012-04-09 17:08:06 -0600 | [diff] [blame] | 1309 | if (frontswap) { |
| 1310 | if (frontswap_test(si, i)) |
| 1311 | break; |
| 1312 | else |
| 1313 | continue; |
| 1314 | } |
Jason Low | 4db0c3c | 2015-04-15 16:14:08 -0700 | [diff] [blame] | 1315 | count = READ_ONCE(si->swap_map[i]); |
KAMEZAWA Hiroyuki | 355cfa7 | 2009-06-16 15:32:53 -0700 | [diff] [blame] | 1316 | if (count && swap_count(count) != SWAP_MAP_BAD) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1317 | break; |
| 1318 | } |
| 1319 | return i; |
| 1320 | } |
| 1321 | |
| 1322 | /* |
| 1323 | * We completely avoid races by reading each swap page in advance, |
| 1324 | * and then search for the process using it. All the necessary |
| 1325 | * page table adjustments can then be made atomically. |
Dan Magenheimer | 38b5faf | 2012-04-09 17:08:06 -0600 | [diff] [blame] | 1326 | * |
| 1327 | * if the boolean frontswap is true, only unuse pages_to_unuse pages; |
| 1328 | * pages_to_unuse==0 means all pages; ignored if frontswap is false |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1329 | */ |
Dan Magenheimer | 38b5faf | 2012-04-09 17:08:06 -0600 | [diff] [blame] | 1330 | int try_to_unuse(unsigned int type, bool frontswap, |
| 1331 | unsigned long pages_to_unuse) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1332 | { |
Hugh Dickins | efa90a9 | 2009-12-14 17:58:41 -0800 | [diff] [blame] | 1333 | struct swap_info_struct *si = swap_info[type]; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1334 | struct mm_struct *start_mm; |
Shaohua Li | edfe23d | 2013-09-11 14:20:31 -0700 | [diff] [blame] | 1335 | volatile unsigned char *swap_map; /* swap_map is accessed without |
| 1336 | * locking. Mark it as volatile |
| 1337 | * to prevent compiler doing |
| 1338 | * something odd. |
| 1339 | */ |
Hugh Dickins | 8d69aae | 2009-12-14 17:58:45 -0800 | [diff] [blame] | 1340 | unsigned char swcount; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1341 | struct page *page; |
| 1342 | swp_entry_t entry; |
Hugh Dickins | 6eb396d | 2005-09-03 15:54:35 -0700 | [diff] [blame] | 1343 | unsigned int i = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1344 | int retval = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1345 | |
| 1346 | /* |
| 1347 | * When searching mms for an entry, a good strategy is to |
| 1348 | * start at the first mm we freed the previous entry from |
| 1349 | * (though actually we don't notice whether we or coincidence |
| 1350 | * freed the entry). Initialize this start_mm with a hold. |
| 1351 | * |
| 1352 | * A simpler strategy would be to start at the last mm we |
| 1353 | * freed the previous entry from; but that would take less |
| 1354 | * advantage of mmlist ordering, which clusters forked mms |
| 1355 | * together, child after parent. If we race with dup_mmap(), we |
| 1356 | * prefer to resolve parent before child, lest we miss entries |
| 1357 | * duplicated after we scanned child: using last mm would invert |
Hugh Dickins | 570a335b | 2009-12-14 17:58:46 -0800 | [diff] [blame] | 1358 | * that. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1359 | */ |
| 1360 | start_mm = &init_mm; |
| 1361 | atomic_inc(&init_mm.mm_users); |
| 1362 | |
| 1363 | /* |
| 1364 | * Keep on scanning until all entries have gone. Usually, |
| 1365 | * one pass through swap_map is enough, but not necessarily: |
| 1366 | * there are races when an instance of an entry might be missed. |
| 1367 | */ |
Dan Magenheimer | 38b5faf | 2012-04-09 17:08:06 -0600 | [diff] [blame] | 1368 | while ((i = find_next_to_unuse(si, i, frontswap)) != 0) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1369 | if (signal_pending(current)) { |
| 1370 | retval = -EINTR; |
| 1371 | break; |
| 1372 | } |
| 1373 | |
Hugh Dickins | 886bb7e | 2009-01-06 14:39:48 -0800 | [diff] [blame] | 1374 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1375 | * Get a page for the entry, using the existing swap |
| 1376 | * cache page if there is one. Otherwise, get a clean |
Hugh Dickins | 886bb7e | 2009-01-06 14:39:48 -0800 | [diff] [blame] | 1377 | * page and read the swap into it. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1378 | */ |
| 1379 | swap_map = &si->swap_map[i]; |
| 1380 | entry = swp_entry(type, i); |
Hugh Dickins | 02098fe | 2008-02-04 22:28:42 -0800 | [diff] [blame] | 1381 | page = read_swap_cache_async(entry, |
| 1382 | GFP_HIGHUSER_MOVABLE, NULL, 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1383 | if (!page) { |
| 1384 | /* |
| 1385 | * Either swap_duplicate() failed because entry |
| 1386 | * has been freed independently, and will not be |
| 1387 | * reused since sys_swapoff() already disabled |
| 1388 | * allocation from here, or alloc_page() failed. |
| 1389 | */ |
Shaohua Li | edfe23d | 2013-09-11 14:20:31 -0700 | [diff] [blame] | 1390 | swcount = *swap_map; |
| 1391 | /* |
| 1392 | * We don't hold lock here, so the swap entry could be |
| 1393 | * SWAP_MAP_BAD (when the cluster is discarding). |
| 1394 | * Instead of fail out, We can just skip the swap |
| 1395 | * entry because swapoff will wait for discarding |
| 1396 | * finish anyway. |
| 1397 | */ |
| 1398 | if (!swcount || swcount == SWAP_MAP_BAD) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1399 | continue; |
| 1400 | retval = -ENOMEM; |
| 1401 | break; |
| 1402 | } |
| 1403 | |
| 1404 | /* |
| 1405 | * Don't hold on to start_mm if it looks like exiting. |
| 1406 | */ |
| 1407 | if (atomic_read(&start_mm->mm_users) == 1) { |
| 1408 | mmput(start_mm); |
| 1409 | start_mm = &init_mm; |
| 1410 | atomic_inc(&init_mm.mm_users); |
| 1411 | } |
| 1412 | |
| 1413 | /* |
| 1414 | * Wait for and lock page. When do_swap_page races with |
| 1415 | * try_to_unuse, do_swap_page can handle the fault much |
| 1416 | * faster than try_to_unuse can locate the entry. This |
| 1417 | * apparently redundant "wait_on_page_locked" lets try_to_unuse |
| 1418 | * defer to do_swap_page in such a case - in some tests, |
| 1419 | * do_swap_page and try_to_unuse repeatedly compete. |
| 1420 | */ |
| 1421 | wait_on_page_locked(page); |
| 1422 | wait_on_page_writeback(page); |
| 1423 | lock_page(page); |
| 1424 | wait_on_page_writeback(page); |
| 1425 | |
| 1426 | /* |
| 1427 | * Remove all references to entry. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1428 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1429 | swcount = *swap_map; |
Hugh Dickins | aaa4686 | 2009-12-14 17:58:47 -0800 | [diff] [blame] | 1430 | if (swap_count(swcount) == SWAP_MAP_SHMEM) { |
| 1431 | retval = shmem_unuse(entry, page); |
| 1432 | /* page has already been unlocked and released */ |
| 1433 | if (retval < 0) |
| 1434 | break; |
| 1435 | continue; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1436 | } |
Hugh Dickins | aaa4686 | 2009-12-14 17:58:47 -0800 | [diff] [blame] | 1437 | if (swap_count(swcount) && start_mm != &init_mm) |
| 1438 | retval = unuse_mm(start_mm, entry, page); |
| 1439 | |
KAMEZAWA Hiroyuki | 355cfa7 | 2009-06-16 15:32:53 -0700 | [diff] [blame] | 1440 | if (swap_count(*swap_map)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1441 | int set_start_mm = (*swap_map >= swcount); |
| 1442 | struct list_head *p = &start_mm->mmlist; |
| 1443 | struct mm_struct *new_start_mm = start_mm; |
| 1444 | struct mm_struct *prev_mm = start_mm; |
| 1445 | struct mm_struct *mm; |
| 1446 | |
| 1447 | atomic_inc(&new_start_mm->mm_users); |
| 1448 | atomic_inc(&prev_mm->mm_users); |
| 1449 | spin_lock(&mmlist_lock); |
Hugh Dickins | aaa4686 | 2009-12-14 17:58:47 -0800 | [diff] [blame] | 1450 | while (swap_count(*swap_map) && !retval && |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1451 | (p = p->next) != &start_mm->mmlist) { |
| 1452 | mm = list_entry(p, struct mm_struct, mmlist); |
Hugh Dickins | 70af7c5 | 2006-06-23 02:03:44 -0700 | [diff] [blame] | 1453 | if (!atomic_inc_not_zero(&mm->mm_users)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1454 | continue; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1455 | spin_unlock(&mmlist_lock); |
| 1456 | mmput(prev_mm); |
| 1457 | prev_mm = mm; |
| 1458 | |
| 1459 | cond_resched(); |
| 1460 | |
| 1461 | swcount = *swap_map; |
KAMEZAWA Hiroyuki | 355cfa7 | 2009-06-16 15:32:53 -0700 | [diff] [blame] | 1462 | if (!swap_count(swcount)) /* any usage ? */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1463 | ; |
Hugh Dickins | aaa4686 | 2009-12-14 17:58:47 -0800 | [diff] [blame] | 1464 | else if (mm == &init_mm) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1465 | set_start_mm = 1; |
Hugh Dickins | aaa4686 | 2009-12-14 17:58:47 -0800 | [diff] [blame] | 1466 | else |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1467 | retval = unuse_mm(mm, entry, page); |
KAMEZAWA Hiroyuki | 355cfa7 | 2009-06-16 15:32:53 -0700 | [diff] [blame] | 1468 | |
Bo Liu | 32c5fc1 | 2009-11-02 16:50:33 +0000 | [diff] [blame] | 1469 | if (set_start_mm && *swap_map < swcount) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1470 | mmput(new_start_mm); |
| 1471 | atomic_inc(&mm->mm_users); |
| 1472 | new_start_mm = mm; |
| 1473 | set_start_mm = 0; |
| 1474 | } |
| 1475 | spin_lock(&mmlist_lock); |
| 1476 | } |
| 1477 | spin_unlock(&mmlist_lock); |
| 1478 | mmput(prev_mm); |
| 1479 | mmput(start_mm); |
| 1480 | start_mm = new_start_mm; |
| 1481 | } |
| 1482 | if (retval) { |
| 1483 | unlock_page(page); |
| 1484 | page_cache_release(page); |
| 1485 | break; |
| 1486 | } |
| 1487 | |
| 1488 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1489 | * If a reference remains (rare), we would like to leave |
| 1490 | * the page in the swap cache; but try_to_unmap could |
| 1491 | * then re-duplicate the entry once we drop page lock, |
| 1492 | * so we might loop indefinitely; also, that page could |
| 1493 | * not be swapped out to other storage meanwhile. So: |
| 1494 | * delete from cache even if there's another reference, |
| 1495 | * after ensuring that the data has been saved to disk - |
| 1496 | * since if the reference remains (rarer), it will be |
| 1497 | * read from disk into another page. Splitting into two |
| 1498 | * pages would be incorrect if swap supported "shared |
| 1499 | * private" pages, but they are handled by tmpfs files. |
Hugh Dickins | 5ad6468 | 2009-12-14 17:59:24 -0800 | [diff] [blame] | 1500 | * |
| 1501 | * Given how unuse_vma() targets one particular offset |
| 1502 | * in an anon_vma, once the anon_vma has been determined, |
| 1503 | * this splitting happens to be just what is needed to |
| 1504 | * handle where KSM pages have been swapped out: re-reading |
| 1505 | * is unnecessarily slow, but we can fix that later on. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1506 | */ |
KAMEZAWA Hiroyuki | 355cfa7 | 2009-06-16 15:32:53 -0700 | [diff] [blame] | 1507 | if (swap_count(*swap_map) && |
| 1508 | PageDirty(page) && PageSwapCache(page)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1509 | struct writeback_control wbc = { |
| 1510 | .sync_mode = WB_SYNC_NONE, |
| 1511 | }; |
| 1512 | |
| 1513 | swap_writepage(page, &wbc); |
| 1514 | lock_page(page); |
| 1515 | wait_on_page_writeback(page); |
| 1516 | } |
Hugh Dickins | 68bdc8d | 2009-01-06 14:39:37 -0800 | [diff] [blame] | 1517 | |
| 1518 | /* |
| 1519 | * It is conceivable that a racing task removed this page from |
| 1520 | * swap cache just before we acquired the page lock at the top, |
| 1521 | * or while we dropped it in unuse_mm(). The page might even |
| 1522 | * be back in swap cache on another swap area: that we must not |
| 1523 | * delete, since it may not have been written out to swap yet. |
| 1524 | */ |
| 1525 | if (PageSwapCache(page) && |
| 1526 | likely(page_private(page) == entry.val)) |
Hugh Dickins | 2e0e26c | 2008-02-04 22:28:53 -0800 | [diff] [blame] | 1527 | delete_from_swap_cache(page); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1528 | |
| 1529 | /* |
| 1530 | * So we could skip searching mms once swap count went |
| 1531 | * to 1, we did not mark any present ptes as dirty: must |
Anderson Briglia | 2706a1b | 2007-07-15 23:38:09 -0700 | [diff] [blame] | 1532 | * mark page dirty so shrink_page_list will preserve it. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1533 | */ |
| 1534 | SetPageDirty(page); |
| 1535 | unlock_page(page); |
| 1536 | page_cache_release(page); |
| 1537 | |
| 1538 | /* |
| 1539 | * Make sure that we aren't completely killing |
| 1540 | * interactive performance. |
| 1541 | */ |
| 1542 | cond_resched(); |
Dan Magenheimer | 38b5faf | 2012-04-09 17:08:06 -0600 | [diff] [blame] | 1543 | if (frontswap && pages_to_unuse > 0) { |
| 1544 | if (!--pages_to_unuse) |
| 1545 | break; |
| 1546 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1547 | } |
| 1548 | |
| 1549 | mmput(start_mm); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1550 | return retval; |
| 1551 | } |
| 1552 | |
| 1553 | /* |
Hugh Dickins | 5d337b9 | 2005-09-03 15:54:41 -0700 | [diff] [blame] | 1554 | * After a successful try_to_unuse, if no swap is now in use, we know |
| 1555 | * we can empty the mmlist. swap_lock must be held on entry and exit. |
| 1556 | * Note that mmlist_lock nests inside swap_lock, and an mm must be |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1557 | * added to the mmlist just after page_duplicate - before would be racy. |
| 1558 | */ |
| 1559 | static void drain_mmlist(void) |
| 1560 | { |
| 1561 | struct list_head *p, *next; |
Hugh Dickins | efa90a9 | 2009-12-14 17:58:41 -0800 | [diff] [blame] | 1562 | unsigned int type; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1563 | |
Hugh Dickins | efa90a9 | 2009-12-14 17:58:41 -0800 | [diff] [blame] | 1564 | for (type = 0; type < nr_swapfiles; type++) |
| 1565 | if (swap_info[type]->inuse_pages) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1566 | return; |
| 1567 | spin_lock(&mmlist_lock); |
| 1568 | list_for_each_safe(p, next, &init_mm.mmlist) |
| 1569 | list_del_init(p); |
| 1570 | spin_unlock(&mmlist_lock); |
| 1571 | } |
| 1572 | |
| 1573 | /* |
| 1574 | * Use this swapdev's extent info to locate the (PAGE_SIZE) block which |
Lee Schermerhorn | d4906e1 | 2009-12-14 17:58:49 -0800 | [diff] [blame] | 1575 | * corresponds to page offset for the specified swap entry. |
| 1576 | * Note that the type of this function is sector_t, but it returns page offset |
| 1577 | * into the bdev, not sector offset. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1578 | */ |
Lee Schermerhorn | d4906e1 | 2009-12-14 17:58:49 -0800 | [diff] [blame] | 1579 | static sector_t map_swap_entry(swp_entry_t entry, struct block_device **bdev) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1580 | { |
Hugh Dickins | f29ad6a | 2009-12-14 17:58:40 -0800 | [diff] [blame] | 1581 | struct swap_info_struct *sis; |
| 1582 | struct swap_extent *start_se; |
| 1583 | struct swap_extent *se; |
| 1584 | pgoff_t offset; |
| 1585 | |
Hugh Dickins | efa90a9 | 2009-12-14 17:58:41 -0800 | [diff] [blame] | 1586 | sis = swap_info[swp_type(entry)]; |
Hugh Dickins | f29ad6a | 2009-12-14 17:58:40 -0800 | [diff] [blame] | 1587 | *bdev = sis->bdev; |
| 1588 | |
| 1589 | offset = swp_offset(entry); |
| 1590 | start_se = sis->curr_swap_extent; |
| 1591 | se = start_se; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1592 | |
| 1593 | for ( ; ; ) { |
| 1594 | struct list_head *lh; |
| 1595 | |
| 1596 | if (se->start_page <= offset && |
| 1597 | offset < (se->start_page + se->nr_pages)) { |
| 1598 | return se->start_block + (offset - se->start_page); |
| 1599 | } |
Hugh Dickins | 11d3188 | 2005-09-03 15:54:34 -0700 | [diff] [blame] | 1600 | lh = se->list.next; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1601 | se = list_entry(lh, struct swap_extent, list); |
| 1602 | sis->curr_swap_extent = se; |
| 1603 | BUG_ON(se == start_se); /* It *must* be present */ |
| 1604 | } |
| 1605 | } |
| 1606 | |
| 1607 | /* |
Lee Schermerhorn | d4906e1 | 2009-12-14 17:58:49 -0800 | [diff] [blame] | 1608 | * Returns the page offset into bdev for the specified page's swap entry. |
| 1609 | */ |
| 1610 | sector_t map_swap_page(struct page *page, struct block_device **bdev) |
| 1611 | { |
| 1612 | swp_entry_t entry; |
| 1613 | entry.val = page_private(page); |
| 1614 | return map_swap_entry(entry, bdev); |
| 1615 | } |
| 1616 | |
| 1617 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1618 | * Free all of a swapdev's extent information |
| 1619 | */ |
| 1620 | static void destroy_swap_extents(struct swap_info_struct *sis) |
| 1621 | { |
Hugh Dickins | 9625a5f | 2009-12-14 17:58:42 -0800 | [diff] [blame] | 1622 | while (!list_empty(&sis->first_swap_extent.list)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1623 | struct swap_extent *se; |
| 1624 | |
Hugh Dickins | 9625a5f | 2009-12-14 17:58:42 -0800 | [diff] [blame] | 1625 | se = list_entry(sis->first_swap_extent.list.next, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1626 | struct swap_extent, list); |
| 1627 | list_del(&se->list); |
| 1628 | kfree(se); |
| 1629 | } |
Mel Gorman | 62c230b | 2012-07-31 16:44:55 -0700 | [diff] [blame] | 1630 | |
| 1631 | if (sis->flags & SWP_FILE) { |
| 1632 | struct file *swap_file = sis->swap_file; |
| 1633 | struct address_space *mapping = swap_file->f_mapping; |
| 1634 | |
| 1635 | sis->flags &= ~SWP_FILE; |
| 1636 | mapping->a_ops->swap_deactivate(swap_file); |
| 1637 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1638 | } |
| 1639 | |
| 1640 | /* |
| 1641 | * Add a block range (and the corresponding page range) into this swapdev's |
Hugh Dickins | 11d3188 | 2005-09-03 15:54:34 -0700 | [diff] [blame] | 1642 | * extent list. The extent list is kept sorted in page order. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1643 | * |
Hugh Dickins | 11d3188 | 2005-09-03 15:54:34 -0700 | [diff] [blame] | 1644 | * This function rather assumes that it is called in ascending page order. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1645 | */ |
Mel Gorman | a509bc1 | 2012-07-31 16:44:57 -0700 | [diff] [blame] | 1646 | int |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1647 | add_swap_extent(struct swap_info_struct *sis, unsigned long start_page, |
| 1648 | unsigned long nr_pages, sector_t start_block) |
| 1649 | { |
| 1650 | struct swap_extent *se; |
| 1651 | struct swap_extent *new_se; |
| 1652 | struct list_head *lh; |
| 1653 | |
Hugh Dickins | 9625a5f | 2009-12-14 17:58:42 -0800 | [diff] [blame] | 1654 | if (start_page == 0) { |
| 1655 | se = &sis->first_swap_extent; |
| 1656 | sis->curr_swap_extent = se; |
| 1657 | se->start_page = 0; |
| 1658 | se->nr_pages = nr_pages; |
| 1659 | se->start_block = start_block; |
| 1660 | return 1; |
| 1661 | } else { |
| 1662 | lh = sis->first_swap_extent.list.prev; /* Highest extent */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1663 | se = list_entry(lh, struct swap_extent, list); |
Hugh Dickins | 11d3188 | 2005-09-03 15:54:34 -0700 | [diff] [blame] | 1664 | BUG_ON(se->start_page + se->nr_pages != start_page); |
| 1665 | if (se->start_block + se->nr_pages == start_block) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1666 | /* Merge it */ |
| 1667 | se->nr_pages += nr_pages; |
| 1668 | return 0; |
| 1669 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1670 | } |
| 1671 | |
| 1672 | /* |
| 1673 | * No merge. Insert a new extent, preserving ordering. |
| 1674 | */ |
| 1675 | new_se = kmalloc(sizeof(*se), GFP_KERNEL); |
| 1676 | if (new_se == NULL) |
| 1677 | return -ENOMEM; |
| 1678 | new_se->start_page = start_page; |
| 1679 | new_se->nr_pages = nr_pages; |
| 1680 | new_se->start_block = start_block; |
| 1681 | |
Hugh Dickins | 9625a5f | 2009-12-14 17:58:42 -0800 | [diff] [blame] | 1682 | list_add_tail(&new_se->list, &sis->first_swap_extent.list); |
Hugh Dickins | 53092a7 | 2005-09-03 15:54:34 -0700 | [diff] [blame] | 1683 | return 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1684 | } |
| 1685 | |
| 1686 | /* |
| 1687 | * A `swap extent' is a simple thing which maps a contiguous range of pages |
| 1688 | * onto a contiguous range of disk blocks. An ordered list of swap extents |
| 1689 | * is built at swapon time and is then used at swap_writepage/swap_readpage |
| 1690 | * time for locating where on disk a page belongs. |
| 1691 | * |
| 1692 | * If the swapfile is an S_ISBLK block device, a single extent is installed. |
| 1693 | * This is done so that the main operating code can treat S_ISBLK and S_ISREG |
| 1694 | * swap files identically. |
| 1695 | * |
| 1696 | * Whether the swapdev is an S_ISREG file or an S_ISBLK blockdev, the swap |
| 1697 | * extent list operates in PAGE_SIZE disk blocks. Both S_ISREG and S_ISBLK |
| 1698 | * swapfiles are handled *identically* after swapon time. |
| 1699 | * |
| 1700 | * For S_ISREG swapfiles, setup_swap_extents() will walk all the file's blocks |
| 1701 | * and will parse them into an ordered extent list, in PAGE_SIZE chunks. If |
| 1702 | * some stray blocks are found which do not fall within the PAGE_SIZE alignment |
| 1703 | * requirements, they are simply tossed out - we will never use those blocks |
| 1704 | * for swapping. |
| 1705 | * |
Hugh Dickins | b0d9bcd | 2005-09-03 15:54:31 -0700 | [diff] [blame] | 1706 | * For S_ISREG swapfiles we set S_SWAPFILE across the life of the swapon. This |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1707 | * prevents root from shooting her foot off by ftruncating an in-use swapfile, |
| 1708 | * which will scribble on the fs. |
| 1709 | * |
| 1710 | * The amount of disk space which a single swap extent represents varies. |
| 1711 | * Typically it is in the 1-4 megabyte range. So we can have hundreds of |
| 1712 | * extents in the list. To avoid much list walking, we cache the previous |
| 1713 | * search location in `curr_swap_extent', and start new searches from there. |
| 1714 | * This is extremely effective. The average number of iterations in |
| 1715 | * map_swap_page() has been measured at about 0.3 per page. - akpm. |
| 1716 | */ |
Hugh Dickins | 53092a7 | 2005-09-03 15:54:34 -0700 | [diff] [blame] | 1717 | static int setup_swap_extents(struct swap_info_struct *sis, sector_t *span) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1718 | { |
Mel Gorman | 62c230b | 2012-07-31 16:44:55 -0700 | [diff] [blame] | 1719 | struct file *swap_file = sis->swap_file; |
| 1720 | struct address_space *mapping = swap_file->f_mapping; |
| 1721 | struct inode *inode = mapping->host; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1722 | int ret; |
| 1723 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1724 | if (S_ISBLK(inode->i_mode)) { |
| 1725 | ret = add_swap_extent(sis, 0, sis->max, 0); |
Hugh Dickins | 53092a7 | 2005-09-03 15:54:34 -0700 | [diff] [blame] | 1726 | *span = sis->pages; |
Mel Gorman | a509bc1 | 2012-07-31 16:44:57 -0700 | [diff] [blame] | 1727 | return ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1728 | } |
| 1729 | |
Mel Gorman | 62c230b | 2012-07-31 16:44:55 -0700 | [diff] [blame] | 1730 | if (mapping->a_ops->swap_activate) { |
Mel Gorman | a509bc1 | 2012-07-31 16:44:57 -0700 | [diff] [blame] | 1731 | ret = mapping->a_ops->swap_activate(sis, swap_file, span); |
Mel Gorman | 62c230b | 2012-07-31 16:44:55 -0700 | [diff] [blame] | 1732 | if (!ret) { |
| 1733 | sis->flags |= SWP_FILE; |
| 1734 | ret = add_swap_extent(sis, 0, sis->max, 0); |
| 1735 | *span = sis->pages; |
| 1736 | } |
Mel Gorman | a509bc1 | 2012-07-31 16:44:57 -0700 | [diff] [blame] | 1737 | return ret; |
Mel Gorman | 62c230b | 2012-07-31 16:44:55 -0700 | [diff] [blame] | 1738 | } |
| 1739 | |
Mel Gorman | a509bc1 | 2012-07-31 16:44:57 -0700 | [diff] [blame] | 1740 | return generic_swapfile_activate(sis, swap_file, span); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1741 | } |
| 1742 | |
Cesar Eduardo Barros | cf0cac0 | 2012-12-11 16:01:13 -0800 | [diff] [blame] | 1743 | static void _enable_swap_info(struct swap_info_struct *p, int prio, |
Shaohua Li | 2a8f944 | 2013-09-11 14:20:28 -0700 | [diff] [blame] | 1744 | unsigned char *swap_map, |
| 1745 | struct swap_cluster_info *cluster_info) |
Cesar Eduardo Barros | 4053154 | 2011-03-22 16:33:37 -0700 | [diff] [blame] | 1746 | { |
Cesar Eduardo Barros | 4053154 | 2011-03-22 16:33:37 -0700 | [diff] [blame] | 1747 | if (prio >= 0) |
| 1748 | p->prio = prio; |
| 1749 | else |
| 1750 | p->prio = --least_priority; |
Dan Streetman | 18ab4d4 | 2014-06-04 16:09:59 -0700 | [diff] [blame] | 1751 | /* |
| 1752 | * the plist prio is negated because plist ordering is |
| 1753 | * low-to-high, while swap ordering is high-to-low |
| 1754 | */ |
| 1755 | p->list.prio = -p->prio; |
| 1756 | p->avail_list.prio = -p->prio; |
Cesar Eduardo Barros | 4053154 | 2011-03-22 16:33:37 -0700 | [diff] [blame] | 1757 | p->swap_map = swap_map; |
Shaohua Li | 2a8f944 | 2013-09-11 14:20:28 -0700 | [diff] [blame] | 1758 | p->cluster_info = cluster_info; |
Cesar Eduardo Barros | 4053154 | 2011-03-22 16:33:37 -0700 | [diff] [blame] | 1759 | p->flags |= SWP_WRITEOK; |
Shaohua Li | ec8acf2 | 2013-02-22 16:34:38 -0800 | [diff] [blame] | 1760 | atomic_long_add(p->pages, &nr_swap_pages); |
Cesar Eduardo Barros | 4053154 | 2011-03-22 16:33:37 -0700 | [diff] [blame] | 1761 | total_swap_pages += p->pages; |
| 1762 | |
Dan Streetman | adfab83 | 2014-06-04 16:09:53 -0700 | [diff] [blame] | 1763 | assert_spin_locked(&swap_lock); |
Dan Streetman | adfab83 | 2014-06-04 16:09:53 -0700 | [diff] [blame] | 1764 | /* |
Dan Streetman | 18ab4d4 | 2014-06-04 16:09:59 -0700 | [diff] [blame] | 1765 | * both lists are plists, and thus priority ordered. |
| 1766 | * swap_active_head needs to be priority ordered for swapoff(), |
| 1767 | * which on removal of any swap_info_struct with an auto-assigned |
| 1768 | * (i.e. negative) priority increments the auto-assigned priority |
| 1769 | * of any lower-priority swap_info_structs. |
| 1770 | * swap_avail_head needs to be priority ordered for get_swap_page(), |
| 1771 | * which allocates swap pages from the highest available priority |
| 1772 | * swap_info_struct. |
Dan Streetman | adfab83 | 2014-06-04 16:09:53 -0700 | [diff] [blame] | 1773 | */ |
Dan Streetman | 18ab4d4 | 2014-06-04 16:09:59 -0700 | [diff] [blame] | 1774 | plist_add(&p->list, &swap_active_head); |
| 1775 | spin_lock(&swap_avail_lock); |
| 1776 | plist_add(&p->avail_list, &swap_avail_head); |
| 1777 | spin_unlock(&swap_avail_lock); |
Cesar Eduardo Barros | cf0cac0 | 2012-12-11 16:01:13 -0800 | [diff] [blame] | 1778 | } |
| 1779 | |
| 1780 | static void enable_swap_info(struct swap_info_struct *p, int prio, |
| 1781 | unsigned char *swap_map, |
Shaohua Li | 2a8f944 | 2013-09-11 14:20:28 -0700 | [diff] [blame] | 1782 | struct swap_cluster_info *cluster_info, |
Cesar Eduardo Barros | cf0cac0 | 2012-12-11 16:01:13 -0800 | [diff] [blame] | 1783 | unsigned long *frontswap_map) |
| 1784 | { |
Minchan Kim | 4f89849 | 2013-04-30 15:26:54 -0700 | [diff] [blame] | 1785 | frontswap_init(p->type, frontswap_map); |
Cesar Eduardo Barros | cf0cac0 | 2012-12-11 16:01:13 -0800 | [diff] [blame] | 1786 | spin_lock(&swap_lock); |
Shaohua Li | ec8acf2 | 2013-02-22 16:34:38 -0800 | [diff] [blame] | 1787 | spin_lock(&p->lock); |
Shaohua Li | 2a8f944 | 2013-09-11 14:20:28 -0700 | [diff] [blame] | 1788 | _enable_swap_info(p, prio, swap_map, cluster_info); |
Shaohua Li | ec8acf2 | 2013-02-22 16:34:38 -0800 | [diff] [blame] | 1789 | spin_unlock(&p->lock); |
Cesar Eduardo Barros | cf0cac0 | 2012-12-11 16:01:13 -0800 | [diff] [blame] | 1790 | spin_unlock(&swap_lock); |
| 1791 | } |
| 1792 | |
| 1793 | static void reinsert_swap_info(struct swap_info_struct *p) |
| 1794 | { |
| 1795 | spin_lock(&swap_lock); |
Shaohua Li | ec8acf2 | 2013-02-22 16:34:38 -0800 | [diff] [blame] | 1796 | spin_lock(&p->lock); |
Shaohua Li | 2a8f944 | 2013-09-11 14:20:28 -0700 | [diff] [blame] | 1797 | _enable_swap_info(p, p->prio, p->swap_map, p->cluster_info); |
Shaohua Li | ec8acf2 | 2013-02-22 16:34:38 -0800 | [diff] [blame] | 1798 | spin_unlock(&p->lock); |
Cesar Eduardo Barros | 4053154 | 2011-03-22 16:33:37 -0700 | [diff] [blame] | 1799 | spin_unlock(&swap_lock); |
| 1800 | } |
| 1801 | |
Heiko Carstens | c4ea37c | 2009-01-14 14:14:28 +0100 | [diff] [blame] | 1802 | SYSCALL_DEFINE1(swapoff, const char __user *, specialfile) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1803 | { |
Hugh Dickins | 73c34b6 | 2009-12-14 17:58:43 -0800 | [diff] [blame] | 1804 | struct swap_info_struct *p = NULL; |
Hugh Dickins | 8d69aae | 2009-12-14 17:58:45 -0800 | [diff] [blame] | 1805 | unsigned char *swap_map; |
Shaohua Li | 2a8f944 | 2013-09-11 14:20:28 -0700 | [diff] [blame] | 1806 | struct swap_cluster_info *cluster_info; |
Minchan Kim | 4f89849 | 2013-04-30 15:26:54 -0700 | [diff] [blame] | 1807 | unsigned long *frontswap_map; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1808 | struct file *swap_file, *victim; |
| 1809 | struct address_space *mapping; |
| 1810 | struct inode *inode; |
Jeff Layton | 91a27b2 | 2012-10-10 15:25:28 -0400 | [diff] [blame] | 1811 | struct filename *pathname; |
Dan Streetman | adfab83 | 2014-06-04 16:09:53 -0700 | [diff] [blame] | 1812 | int err, found = 0; |
Krzysztof Kozlowski | 5b808a2 | 2013-10-16 13:47:06 -0700 | [diff] [blame] | 1813 | unsigned int old_block_size; |
Hugh Dickins | 886bb7e | 2009-01-06 14:39:48 -0800 | [diff] [blame] | 1814 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1815 | if (!capable(CAP_SYS_ADMIN)) |
| 1816 | return -EPERM; |
| 1817 | |
Al Viro | 191c542 | 2012-02-13 03:58:52 +0000 | [diff] [blame] | 1818 | BUG_ON(!current->mm); |
| 1819 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1820 | pathname = getname(specialfile); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1821 | if (IS_ERR(pathname)) |
Xiaotian Feng | f58b59c | 2012-11-16 14:14:55 -0800 | [diff] [blame] | 1822 | return PTR_ERR(pathname); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1823 | |
Jeff Layton | 669abf4 | 2012-10-10 16:43:10 -0400 | [diff] [blame] | 1824 | victim = file_open_name(pathname, O_RDWR|O_LARGEFILE, 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1825 | err = PTR_ERR(victim); |
| 1826 | if (IS_ERR(victim)) |
| 1827 | goto out; |
| 1828 | |
| 1829 | mapping = victim->f_mapping; |
Hugh Dickins | 5d337b9 | 2005-09-03 15:54:41 -0700 | [diff] [blame] | 1830 | spin_lock(&swap_lock); |
Dan Streetman | 18ab4d4 | 2014-06-04 16:09:59 -0700 | [diff] [blame] | 1831 | plist_for_each_entry(p, &swap_active_head, list) { |
Hugh Dickins | 22c6f8fd | 2009-01-06 14:39:48 -0800 | [diff] [blame] | 1832 | if (p->flags & SWP_WRITEOK) { |
Dan Streetman | adfab83 | 2014-06-04 16:09:53 -0700 | [diff] [blame] | 1833 | if (p->swap_file->f_mapping == mapping) { |
| 1834 | found = 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1835 | break; |
Dan Streetman | adfab83 | 2014-06-04 16:09:53 -0700 | [diff] [blame] | 1836 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1837 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1838 | } |
Dan Streetman | adfab83 | 2014-06-04 16:09:53 -0700 | [diff] [blame] | 1839 | if (!found) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1840 | err = -EINVAL; |
Hugh Dickins | 5d337b9 | 2005-09-03 15:54:41 -0700 | [diff] [blame] | 1841 | spin_unlock(&swap_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1842 | goto out_dput; |
| 1843 | } |
Al Viro | 191c542 | 2012-02-13 03:58:52 +0000 | [diff] [blame] | 1844 | if (!security_vm_enough_memory_mm(current->mm, p->pages)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1845 | vm_unacct_memory(p->pages); |
| 1846 | else { |
| 1847 | err = -ENOMEM; |
Hugh Dickins | 5d337b9 | 2005-09-03 15:54:41 -0700 | [diff] [blame] | 1848 | spin_unlock(&swap_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1849 | goto out_dput; |
| 1850 | } |
Dan Streetman | 18ab4d4 | 2014-06-04 16:09:59 -0700 | [diff] [blame] | 1851 | spin_lock(&swap_avail_lock); |
| 1852 | plist_del(&p->avail_list, &swap_avail_head); |
| 1853 | spin_unlock(&swap_avail_lock); |
Shaohua Li | ec8acf2 | 2013-02-22 16:34:38 -0800 | [diff] [blame] | 1854 | spin_lock(&p->lock); |
Hugh Dickins | 78ecba0 | 2008-07-23 21:28:23 -0700 | [diff] [blame] | 1855 | if (p->prio < 0) { |
Dan Streetman | adfab83 | 2014-06-04 16:09:53 -0700 | [diff] [blame] | 1856 | struct swap_info_struct *si = p; |
| 1857 | |
Dan Streetman | 18ab4d4 | 2014-06-04 16:09:59 -0700 | [diff] [blame] | 1858 | plist_for_each_entry_continue(si, &swap_active_head, list) { |
Dan Streetman | adfab83 | 2014-06-04 16:09:53 -0700 | [diff] [blame] | 1859 | si->prio++; |
Dan Streetman | 18ab4d4 | 2014-06-04 16:09:59 -0700 | [diff] [blame] | 1860 | si->list.prio--; |
| 1861 | si->avail_list.prio--; |
Dan Streetman | adfab83 | 2014-06-04 16:09:53 -0700 | [diff] [blame] | 1862 | } |
Hugh Dickins | 78ecba0 | 2008-07-23 21:28:23 -0700 | [diff] [blame] | 1863 | least_priority++; |
| 1864 | } |
Dan Streetman | 18ab4d4 | 2014-06-04 16:09:59 -0700 | [diff] [blame] | 1865 | plist_del(&p->list, &swap_active_head); |
Shaohua Li | ec8acf2 | 2013-02-22 16:34:38 -0800 | [diff] [blame] | 1866 | atomic_long_sub(p->pages, &nr_swap_pages); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1867 | total_swap_pages -= p->pages; |
| 1868 | p->flags &= ~SWP_WRITEOK; |
Shaohua Li | ec8acf2 | 2013-02-22 16:34:38 -0800 | [diff] [blame] | 1869 | spin_unlock(&p->lock); |
Hugh Dickins | 5d337b9 | 2005-09-03 15:54:41 -0700 | [diff] [blame] | 1870 | spin_unlock(&swap_lock); |
Hugh Dickins | fb4f88d | 2005-09-03 15:54:37 -0700 | [diff] [blame] | 1871 | |
David Rientjes | e1e12d2 | 2012-12-11 16:02:56 -0800 | [diff] [blame] | 1872 | set_current_oom_origin(); |
Dan Streetman | adfab83 | 2014-06-04 16:09:53 -0700 | [diff] [blame] | 1873 | err = try_to_unuse(p->type, false, 0); /* force unuse all pages */ |
David Rientjes | e1e12d2 | 2012-12-11 16:02:56 -0800 | [diff] [blame] | 1874 | clear_current_oom_origin(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1875 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1876 | if (err) { |
| 1877 | /* re-insert swap space back into swap_list */ |
Cesar Eduardo Barros | cf0cac0 | 2012-12-11 16:01:13 -0800 | [diff] [blame] | 1878 | reinsert_swap_info(p); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1879 | goto out_dput; |
| 1880 | } |
Hugh Dickins | 52b7efdb | 2005-09-03 15:54:39 -0700 | [diff] [blame] | 1881 | |
Shaohua Li | 815c2c5 | 2013-09-11 14:20:30 -0700 | [diff] [blame] | 1882 | flush_work(&p->discard_work); |
| 1883 | |
Hugh Dickins | 4cd3bb1 | 2005-09-03 15:54:33 -0700 | [diff] [blame] | 1884 | destroy_swap_extents(p); |
Hugh Dickins | 570a335b | 2009-12-14 17:58:46 -0800 | [diff] [blame] | 1885 | if (p->flags & SWP_CONTINUED) |
| 1886 | free_swap_count_continuations(p); |
| 1887 | |
Ingo Molnar | fc0abb1 | 2006-01-18 17:42:33 -0800 | [diff] [blame] | 1888 | mutex_lock(&swapon_mutex); |
Hugh Dickins | 5d337b9 | 2005-09-03 15:54:41 -0700 | [diff] [blame] | 1889 | spin_lock(&swap_lock); |
Shaohua Li | ec8acf2 | 2013-02-22 16:34:38 -0800 | [diff] [blame] | 1890 | spin_lock(&p->lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1891 | drain_mmlist(); |
Hugh Dickins | 5d337b9 | 2005-09-03 15:54:41 -0700 | [diff] [blame] | 1892 | |
| 1893 | /* wait for anyone still in scan_swap_map */ |
| 1894 | p->highest_bit = 0; /* cuts scans short */ |
| 1895 | while (p->flags >= SWP_SCANNING) { |
Shaohua Li | ec8acf2 | 2013-02-22 16:34:38 -0800 | [diff] [blame] | 1896 | spin_unlock(&p->lock); |
Hugh Dickins | 5d337b9 | 2005-09-03 15:54:41 -0700 | [diff] [blame] | 1897 | spin_unlock(&swap_lock); |
Nishanth Aravamudan | 13e4b57 | 2005-09-10 00:27:25 -0700 | [diff] [blame] | 1898 | schedule_timeout_uninterruptible(1); |
Hugh Dickins | 5d337b9 | 2005-09-03 15:54:41 -0700 | [diff] [blame] | 1899 | spin_lock(&swap_lock); |
Shaohua Li | ec8acf2 | 2013-02-22 16:34:38 -0800 | [diff] [blame] | 1900 | spin_lock(&p->lock); |
Hugh Dickins | 5d337b9 | 2005-09-03 15:54:41 -0700 | [diff] [blame] | 1901 | } |
| 1902 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1903 | swap_file = p->swap_file; |
Krzysztof Kozlowski | 5b808a2 | 2013-10-16 13:47:06 -0700 | [diff] [blame] | 1904 | old_block_size = p->old_block_size; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1905 | p->swap_file = NULL; |
| 1906 | p->max = 0; |
| 1907 | swap_map = p->swap_map; |
| 1908 | p->swap_map = NULL; |
Shaohua Li | 2a8f944 | 2013-09-11 14:20:28 -0700 | [diff] [blame] | 1909 | cluster_info = p->cluster_info; |
| 1910 | p->cluster_info = NULL; |
Minchan Kim | 4f89849 | 2013-04-30 15:26:54 -0700 | [diff] [blame] | 1911 | frontswap_map = frontswap_map_get(p); |
Shaohua Li | ec8acf2 | 2013-02-22 16:34:38 -0800 | [diff] [blame] | 1912 | spin_unlock(&p->lock); |
Hugh Dickins | 5d337b9 | 2005-09-03 15:54:41 -0700 | [diff] [blame] | 1913 | spin_unlock(&swap_lock); |
Dan Streetman | adfab83 | 2014-06-04 16:09:53 -0700 | [diff] [blame] | 1914 | frontswap_invalidate_area(p->type); |
Krzysztof Kozlowski | 58e97ba | 2013-11-12 15:07:47 -0800 | [diff] [blame] | 1915 | frontswap_map_set(p, NULL); |
Ingo Molnar | fc0abb1 | 2006-01-18 17:42:33 -0800 | [diff] [blame] | 1916 | mutex_unlock(&swapon_mutex); |
Shaohua Li | ebc2a1a | 2013-09-11 14:20:32 -0700 | [diff] [blame] | 1917 | free_percpu(p->percpu_cluster); |
| 1918 | p->percpu_cluster = NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1919 | vfree(swap_map); |
Shaohua Li | 2a8f944 | 2013-09-11 14:20:28 -0700 | [diff] [blame] | 1920 | vfree(cluster_info); |
Minchan Kim | 4f89849 | 2013-04-30 15:26:54 -0700 | [diff] [blame] | 1921 | vfree(frontswap_map); |
Seth Jennings | 2de1a7e | 2013-11-12 15:07:46 -0800 | [diff] [blame] | 1922 | /* Destroy swap account information */ |
Dan Streetman | adfab83 | 2014-06-04 16:09:53 -0700 | [diff] [blame] | 1923 | swap_cgroup_swapoff(p->type); |
KAMEZAWA Hiroyuki | 27a7faa | 2009-01-07 18:07:58 -0800 | [diff] [blame] | 1924 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1925 | inode = mapping->host; |
| 1926 | if (S_ISBLK(inode->i_mode)) { |
| 1927 | struct block_device *bdev = I_BDEV(inode); |
Krzysztof Kozlowski | 5b808a2 | 2013-10-16 13:47:06 -0700 | [diff] [blame] | 1928 | set_blocksize(bdev, old_block_size); |
Tejun Heo | e525fd8 | 2010-11-13 11:55:17 +0100 | [diff] [blame] | 1929 | blkdev_put(bdev, FMODE_READ | FMODE_WRITE | FMODE_EXCL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1930 | } else { |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 1931 | mutex_lock(&inode->i_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1932 | inode->i_flags &= ~S_SWAPFILE; |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 1933 | mutex_unlock(&inode->i_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1934 | } |
| 1935 | filp_close(swap_file, NULL); |
Weijie Yang | f893ab4 | 2014-02-06 12:04:23 -0800 | [diff] [blame] | 1936 | |
| 1937 | /* |
| 1938 | * Clear the SWP_USED flag after all resources are freed so that swapon |
| 1939 | * can reuse this swap_info in alloc_swap_info() safely. It is ok to |
| 1940 | * not hold p->lock after we cleared its SWP_WRITEOK. |
| 1941 | */ |
| 1942 | spin_lock(&swap_lock); |
| 1943 | p->flags = 0; |
| 1944 | spin_unlock(&swap_lock); |
| 1945 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1946 | err = 0; |
Kay Sievers | 66d7dd5 | 2010-10-26 14:22:06 -0700 | [diff] [blame] | 1947 | atomic_inc(&proc_poll_event); |
| 1948 | wake_up_interruptible(&proc_poll_wait); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1949 | |
| 1950 | out_dput: |
| 1951 | filp_close(victim, NULL); |
| 1952 | out: |
Xiaotian Feng | f58b59c | 2012-11-16 14:14:55 -0800 | [diff] [blame] | 1953 | putname(pathname); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1954 | return err; |
| 1955 | } |
| 1956 | |
| 1957 | #ifdef CONFIG_PROC_FS |
Kay Sievers | 66d7dd5 | 2010-10-26 14:22:06 -0700 | [diff] [blame] | 1958 | static unsigned swaps_poll(struct file *file, poll_table *wait) |
| 1959 | { |
Kay Sievers | f151463 | 2011-07-12 20:48:39 +0200 | [diff] [blame] | 1960 | struct seq_file *seq = file->private_data; |
Kay Sievers | 66d7dd5 | 2010-10-26 14:22:06 -0700 | [diff] [blame] | 1961 | |
| 1962 | poll_wait(file, &proc_poll_wait, wait); |
| 1963 | |
Kay Sievers | f151463 | 2011-07-12 20:48:39 +0200 | [diff] [blame] | 1964 | if (seq->poll_event != atomic_read(&proc_poll_event)) { |
| 1965 | seq->poll_event = atomic_read(&proc_poll_event); |
Kay Sievers | 66d7dd5 | 2010-10-26 14:22:06 -0700 | [diff] [blame] | 1966 | return POLLIN | POLLRDNORM | POLLERR | POLLPRI; |
| 1967 | } |
| 1968 | |
| 1969 | return POLLIN | POLLRDNORM; |
| 1970 | } |
| 1971 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1972 | /* iterator */ |
| 1973 | static void *swap_start(struct seq_file *swap, loff_t *pos) |
| 1974 | { |
Hugh Dickins | efa90a9 | 2009-12-14 17:58:41 -0800 | [diff] [blame] | 1975 | struct swap_info_struct *si; |
| 1976 | int type; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1977 | loff_t l = *pos; |
| 1978 | |
Ingo Molnar | fc0abb1 | 2006-01-18 17:42:33 -0800 | [diff] [blame] | 1979 | mutex_lock(&swapon_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1980 | |
Suleiman Souhlal | 881e4aa | 2006-12-06 20:32:28 -0800 | [diff] [blame] | 1981 | if (!l) |
| 1982 | return SEQ_START_TOKEN; |
| 1983 | |
Hugh Dickins | efa90a9 | 2009-12-14 17:58:41 -0800 | [diff] [blame] | 1984 | for (type = 0; type < nr_swapfiles; type++) { |
| 1985 | smp_rmb(); /* read nr_swapfiles before swap_info[type] */ |
| 1986 | si = swap_info[type]; |
| 1987 | if (!(si->flags & SWP_USED) || !si->swap_map) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1988 | continue; |
Suleiman Souhlal | 881e4aa | 2006-12-06 20:32:28 -0800 | [diff] [blame] | 1989 | if (!--l) |
Hugh Dickins | efa90a9 | 2009-12-14 17:58:41 -0800 | [diff] [blame] | 1990 | return si; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1991 | } |
| 1992 | |
| 1993 | return NULL; |
| 1994 | } |
| 1995 | |
| 1996 | static void *swap_next(struct seq_file *swap, void *v, loff_t *pos) |
| 1997 | { |
Hugh Dickins | efa90a9 | 2009-12-14 17:58:41 -0800 | [diff] [blame] | 1998 | struct swap_info_struct *si = v; |
| 1999 | int type; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2000 | |
Suleiman Souhlal | 881e4aa | 2006-12-06 20:32:28 -0800 | [diff] [blame] | 2001 | if (v == SEQ_START_TOKEN) |
Hugh Dickins | efa90a9 | 2009-12-14 17:58:41 -0800 | [diff] [blame] | 2002 | type = 0; |
| 2003 | else |
| 2004 | type = si->type + 1; |
Suleiman Souhlal | 881e4aa | 2006-12-06 20:32:28 -0800 | [diff] [blame] | 2005 | |
Hugh Dickins | efa90a9 | 2009-12-14 17:58:41 -0800 | [diff] [blame] | 2006 | for (; type < nr_swapfiles; type++) { |
| 2007 | smp_rmb(); /* read nr_swapfiles before swap_info[type] */ |
| 2008 | si = swap_info[type]; |
| 2009 | if (!(si->flags & SWP_USED) || !si->swap_map) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2010 | continue; |
| 2011 | ++*pos; |
Hugh Dickins | efa90a9 | 2009-12-14 17:58:41 -0800 | [diff] [blame] | 2012 | return si; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2013 | } |
| 2014 | |
| 2015 | return NULL; |
| 2016 | } |
| 2017 | |
| 2018 | static void swap_stop(struct seq_file *swap, void *v) |
| 2019 | { |
Ingo Molnar | fc0abb1 | 2006-01-18 17:42:33 -0800 | [diff] [blame] | 2020 | mutex_unlock(&swapon_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2021 | } |
| 2022 | |
| 2023 | static int swap_show(struct seq_file *swap, void *v) |
| 2024 | { |
Hugh Dickins | efa90a9 | 2009-12-14 17:58:41 -0800 | [diff] [blame] | 2025 | struct swap_info_struct *si = v; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2026 | struct file *file; |
| 2027 | int len; |
| 2028 | |
Hugh Dickins | efa90a9 | 2009-12-14 17:58:41 -0800 | [diff] [blame] | 2029 | if (si == SEQ_START_TOKEN) { |
Suleiman Souhlal | 881e4aa | 2006-12-06 20:32:28 -0800 | [diff] [blame] | 2030 | seq_puts(swap,"Filename\t\t\t\tType\t\tSize\tUsed\tPriority\n"); |
| 2031 | return 0; |
| 2032 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2033 | |
Hugh Dickins | efa90a9 | 2009-12-14 17:58:41 -0800 | [diff] [blame] | 2034 | file = si->swap_file; |
Jan Blunck | c32c2f6 | 2008-02-14 19:38:43 -0800 | [diff] [blame] | 2035 | len = seq_path(swap, &file->f_path, " \t\n\\"); |
Hugh Dickins | 6eb396d | 2005-09-03 15:54:35 -0700 | [diff] [blame] | 2036 | seq_printf(swap, "%*s%s\t%u\t%u\t%d\n", |
Hugh Dickins | 886bb7e | 2009-01-06 14:39:48 -0800 | [diff] [blame] | 2037 | len < 40 ? 40 - len : 1, " ", |
Al Viro | 496ad9a | 2013-01-23 17:07:38 -0500 | [diff] [blame] | 2038 | S_ISBLK(file_inode(file)->i_mode) ? |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2039 | "partition" : "file\t", |
Hugh Dickins | efa90a9 | 2009-12-14 17:58:41 -0800 | [diff] [blame] | 2040 | si->pages << (PAGE_SHIFT - 10), |
| 2041 | si->inuse_pages << (PAGE_SHIFT - 10), |
| 2042 | si->prio); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2043 | return 0; |
| 2044 | } |
| 2045 | |
Helge Deller | 15ad7cd | 2006-12-06 20:40:36 -0800 | [diff] [blame] | 2046 | static const struct seq_operations swaps_op = { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2047 | .start = swap_start, |
| 2048 | .next = swap_next, |
| 2049 | .stop = swap_stop, |
| 2050 | .show = swap_show |
| 2051 | }; |
| 2052 | |
| 2053 | static int swaps_open(struct inode *inode, struct file *file) |
| 2054 | { |
Kay Sievers | f151463 | 2011-07-12 20:48:39 +0200 | [diff] [blame] | 2055 | struct seq_file *seq; |
Kay Sievers | 66d7dd5 | 2010-10-26 14:22:06 -0700 | [diff] [blame] | 2056 | int ret; |
| 2057 | |
Kay Sievers | 66d7dd5 | 2010-10-26 14:22:06 -0700 | [diff] [blame] | 2058 | ret = seq_open(file, &swaps_op); |
Kay Sievers | f151463 | 2011-07-12 20:48:39 +0200 | [diff] [blame] | 2059 | if (ret) |
Kay Sievers | 66d7dd5 | 2010-10-26 14:22:06 -0700 | [diff] [blame] | 2060 | return ret; |
Kay Sievers | 66d7dd5 | 2010-10-26 14:22:06 -0700 | [diff] [blame] | 2061 | |
Kay Sievers | f151463 | 2011-07-12 20:48:39 +0200 | [diff] [blame] | 2062 | seq = file->private_data; |
| 2063 | seq->poll_event = atomic_read(&proc_poll_event); |
| 2064 | return 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2065 | } |
| 2066 | |
Helge Deller | 15ad7cd | 2006-12-06 20:40:36 -0800 | [diff] [blame] | 2067 | static const struct file_operations proc_swaps_operations = { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2068 | .open = swaps_open, |
| 2069 | .read = seq_read, |
| 2070 | .llseek = seq_lseek, |
| 2071 | .release = seq_release, |
Kay Sievers | 66d7dd5 | 2010-10-26 14:22:06 -0700 | [diff] [blame] | 2072 | .poll = swaps_poll, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2073 | }; |
| 2074 | |
| 2075 | static int __init procswaps_init(void) |
| 2076 | { |
Denis V. Lunev | 3d71f86 | 2008-04-29 01:02:13 -0700 | [diff] [blame] | 2077 | proc_create("swaps", 0, NULL, &proc_swaps_operations); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2078 | return 0; |
| 2079 | } |
| 2080 | __initcall(procswaps_init); |
| 2081 | #endif /* CONFIG_PROC_FS */ |
| 2082 | |
Jan Beulich | 1796316 | 2008-12-16 11:35:24 +0000 | [diff] [blame] | 2083 | #ifdef MAX_SWAPFILES_CHECK |
| 2084 | static int __init max_swapfiles_check(void) |
| 2085 | { |
| 2086 | MAX_SWAPFILES_CHECK(); |
| 2087 | return 0; |
| 2088 | } |
| 2089 | late_initcall(max_swapfiles_check); |
| 2090 | #endif |
| 2091 | |
Cesar Eduardo Barros | 53cbb24 | 2011-03-22 16:33:17 -0700 | [diff] [blame] | 2092 | static struct swap_info_struct *alloc_swap_info(void) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2093 | { |
Hugh Dickins | 73c34b6 | 2009-12-14 17:58:43 -0800 | [diff] [blame] | 2094 | struct swap_info_struct *p; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2095 | unsigned int type; |
Hugh Dickins | efa90a9 | 2009-12-14 17:58:41 -0800 | [diff] [blame] | 2096 | |
| 2097 | p = kzalloc(sizeof(*p), GFP_KERNEL); |
| 2098 | if (!p) |
Cesar Eduardo Barros | 53cbb24 | 2011-03-22 16:33:17 -0700 | [diff] [blame] | 2099 | return ERR_PTR(-ENOMEM); |
Hugh Dickins | efa90a9 | 2009-12-14 17:58:41 -0800 | [diff] [blame] | 2100 | |
Hugh Dickins | 5d337b9 | 2005-09-03 15:54:41 -0700 | [diff] [blame] | 2101 | spin_lock(&swap_lock); |
Hugh Dickins | efa90a9 | 2009-12-14 17:58:41 -0800 | [diff] [blame] | 2102 | for (type = 0; type < nr_swapfiles; type++) { |
| 2103 | if (!(swap_info[type]->flags & SWP_USED)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2104 | break; |
Hugh Dickins | efa90a9 | 2009-12-14 17:58:41 -0800 | [diff] [blame] | 2105 | } |
Christoph Lameter | 0697212 | 2006-06-23 02:03:35 -0700 | [diff] [blame] | 2106 | if (type >= MAX_SWAPFILES) { |
Hugh Dickins | 5d337b9 | 2005-09-03 15:54:41 -0700 | [diff] [blame] | 2107 | spin_unlock(&swap_lock); |
Hugh Dickins | efa90a9 | 2009-12-14 17:58:41 -0800 | [diff] [blame] | 2108 | kfree(p); |
Cesar Eduardo Barros | 730c058 | 2011-03-22 16:33:19 -0700 | [diff] [blame] | 2109 | return ERR_PTR(-EPERM); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2110 | } |
Hugh Dickins | efa90a9 | 2009-12-14 17:58:41 -0800 | [diff] [blame] | 2111 | if (type >= nr_swapfiles) { |
| 2112 | p->type = type; |
| 2113 | swap_info[type] = p; |
| 2114 | /* |
| 2115 | * Write swap_info[type] before nr_swapfiles, in case a |
| 2116 | * racing procfs swap_start() or swap_next() is reading them. |
| 2117 | * (We never shrink nr_swapfiles, we never free this entry.) |
| 2118 | */ |
| 2119 | smp_wmb(); |
| 2120 | nr_swapfiles++; |
| 2121 | } else { |
| 2122 | kfree(p); |
| 2123 | p = swap_info[type]; |
| 2124 | /* |
| 2125 | * Do not memset this entry: a racing procfs swap_next() |
| 2126 | * would be relying on p->type to remain valid. |
| 2127 | */ |
| 2128 | } |
Hugh Dickins | 9625a5f | 2009-12-14 17:58:42 -0800 | [diff] [blame] | 2129 | INIT_LIST_HEAD(&p->first_swap_extent.list); |
Dan Streetman | 18ab4d4 | 2014-06-04 16:09:59 -0700 | [diff] [blame] | 2130 | plist_node_init(&p->list, 0); |
| 2131 | plist_node_init(&p->avail_list, 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2132 | p->flags = SWP_USED; |
Hugh Dickins | 5d337b9 | 2005-09-03 15:54:41 -0700 | [diff] [blame] | 2133 | spin_unlock(&swap_lock); |
Shaohua Li | ec8acf2 | 2013-02-22 16:34:38 -0800 | [diff] [blame] | 2134 | spin_lock_init(&p->lock); |
Hugh Dickins | efa90a9 | 2009-12-14 17:58:41 -0800 | [diff] [blame] | 2135 | |
Cesar Eduardo Barros | 53cbb24 | 2011-03-22 16:33:17 -0700 | [diff] [blame] | 2136 | return p; |
Cesar Eduardo Barros | 53cbb24 | 2011-03-22 16:33:17 -0700 | [diff] [blame] | 2137 | } |
| 2138 | |
Cesar Eduardo Barros | 4d0e1e1 | 2011-03-22 16:33:26 -0700 | [diff] [blame] | 2139 | static int claim_swapfile(struct swap_info_struct *p, struct inode *inode) |
| 2140 | { |
| 2141 | int error; |
| 2142 | |
| 2143 | if (S_ISBLK(inode->i_mode)) { |
| 2144 | p->bdev = bdgrab(I_BDEV(inode)); |
| 2145 | error = blkdev_get(p->bdev, |
| 2146 | FMODE_READ | FMODE_WRITE | FMODE_EXCL, |
| 2147 | sys_swapon); |
| 2148 | if (error < 0) { |
| 2149 | p->bdev = NULL; |
Cesar Eduardo Barros | 87ade72 | 2011-03-22 16:33:27 -0700 | [diff] [blame] | 2150 | return -EINVAL; |
Cesar Eduardo Barros | 4d0e1e1 | 2011-03-22 16:33:26 -0700 | [diff] [blame] | 2151 | } |
| 2152 | p->old_block_size = block_size(p->bdev); |
| 2153 | error = set_blocksize(p->bdev, PAGE_SIZE); |
| 2154 | if (error < 0) |
Cesar Eduardo Barros | 87ade72 | 2011-03-22 16:33:27 -0700 | [diff] [blame] | 2155 | return error; |
Cesar Eduardo Barros | 4d0e1e1 | 2011-03-22 16:33:26 -0700 | [diff] [blame] | 2156 | p->flags |= SWP_BLKDEV; |
| 2157 | } else if (S_ISREG(inode->i_mode)) { |
| 2158 | p->bdev = inode->i_sb->s_bdev; |
| 2159 | mutex_lock(&inode->i_mutex); |
Cesar Eduardo Barros | 87ade72 | 2011-03-22 16:33:27 -0700 | [diff] [blame] | 2160 | if (IS_SWAPFILE(inode)) |
| 2161 | return -EBUSY; |
| 2162 | } else |
| 2163 | return -EINVAL; |
Cesar Eduardo Barros | 4d0e1e1 | 2011-03-22 16:33:26 -0700 | [diff] [blame] | 2164 | |
| 2165 | return 0; |
Cesar Eduardo Barros | 4d0e1e1 | 2011-03-22 16:33:26 -0700 | [diff] [blame] | 2166 | } |
| 2167 | |
Cesar Eduardo Barros | ca8bd38 | 2011-03-22 16:33:29 -0700 | [diff] [blame] | 2168 | static unsigned long read_swap_header(struct swap_info_struct *p, |
| 2169 | union swap_header *swap_header, |
| 2170 | struct inode *inode) |
| 2171 | { |
| 2172 | int i; |
| 2173 | unsigned long maxpages; |
| 2174 | unsigned long swapfilepages; |
Raymond Jennings | d6bbbd2 | 2013-09-11 14:20:16 -0700 | [diff] [blame] | 2175 | unsigned long last_page; |
Cesar Eduardo Barros | ca8bd38 | 2011-03-22 16:33:29 -0700 | [diff] [blame] | 2176 | |
| 2177 | if (memcmp("SWAPSPACE2", swap_header->magic.magic, 10)) { |
Andrew Morton | 465c47f | 2013-09-11 14:20:17 -0700 | [diff] [blame] | 2178 | pr_err("Unable to find swap-space signature\n"); |
Cesar Eduardo Barros | 3871902 | 2011-03-22 16:33:30 -0700 | [diff] [blame] | 2179 | return 0; |
Cesar Eduardo Barros | ca8bd38 | 2011-03-22 16:33:29 -0700 | [diff] [blame] | 2180 | } |
| 2181 | |
| 2182 | /* swap partition endianess hack... */ |
| 2183 | if (swab32(swap_header->info.version) == 1) { |
| 2184 | swab32s(&swap_header->info.version); |
| 2185 | swab32s(&swap_header->info.last_page); |
| 2186 | swab32s(&swap_header->info.nr_badpages); |
| 2187 | for (i = 0; i < swap_header->info.nr_badpages; i++) |
| 2188 | swab32s(&swap_header->info.badpages[i]); |
| 2189 | } |
| 2190 | /* Check the swap header's sub-version */ |
| 2191 | if (swap_header->info.version != 1) { |
Andrew Morton | 465c47f | 2013-09-11 14:20:17 -0700 | [diff] [blame] | 2192 | pr_warn("Unable to handle swap header version %d\n", |
| 2193 | swap_header->info.version); |
Cesar Eduardo Barros | 3871902 | 2011-03-22 16:33:30 -0700 | [diff] [blame] | 2194 | return 0; |
Cesar Eduardo Barros | ca8bd38 | 2011-03-22 16:33:29 -0700 | [diff] [blame] | 2195 | } |
| 2196 | |
| 2197 | p->lowest_bit = 1; |
| 2198 | p->cluster_next = 1; |
| 2199 | p->cluster_nr = 0; |
| 2200 | |
| 2201 | /* |
| 2202 | * Find out how many pages are allowed for a single swap |
Hugh Dickins | 9b15b81 | 2012-06-15 17:55:50 -0700 | [diff] [blame] | 2203 | * device. There are two limiting factors: 1) the number |
Hugh Dickins | a2c16d6 | 2011-08-03 16:21:19 -0700 | [diff] [blame] | 2204 | * of bits for the swap offset in the swp_entry_t type, and |
| 2205 | * 2) the number of bits in the swap pte as defined by the |
Hugh Dickins | 9b15b81 | 2012-06-15 17:55:50 -0700 | [diff] [blame] | 2206 | * different architectures. In order to find the |
Hugh Dickins | a2c16d6 | 2011-08-03 16:21:19 -0700 | [diff] [blame] | 2207 | * largest possible bit mask, a swap entry with swap type 0 |
Cesar Eduardo Barros | ca8bd38 | 2011-03-22 16:33:29 -0700 | [diff] [blame] | 2208 | * and swap offset ~0UL is created, encoded to a swap pte, |
Hugh Dickins | a2c16d6 | 2011-08-03 16:21:19 -0700 | [diff] [blame] | 2209 | * decoded to a swp_entry_t again, and finally the swap |
Cesar Eduardo Barros | ca8bd38 | 2011-03-22 16:33:29 -0700 | [diff] [blame] | 2210 | * offset is extracted. This will mask all the bits from |
| 2211 | * the initial ~0UL mask that can't be encoded in either |
| 2212 | * the swp_entry_t or the architecture definition of a |
Hugh Dickins | 9b15b81 | 2012-06-15 17:55:50 -0700 | [diff] [blame] | 2213 | * swap pte. |
Cesar Eduardo Barros | ca8bd38 | 2011-03-22 16:33:29 -0700 | [diff] [blame] | 2214 | */ |
| 2215 | maxpages = swp_offset(pte_to_swp_entry( |
Hugh Dickins | 9b15b81 | 2012-06-15 17:55:50 -0700 | [diff] [blame] | 2216 | swp_entry_to_pte(swp_entry(0, ~0UL)))) + 1; |
Raymond Jennings | d6bbbd2 | 2013-09-11 14:20:16 -0700 | [diff] [blame] | 2217 | last_page = swap_header->info.last_page; |
| 2218 | if (last_page > maxpages) { |
Andrew Morton | 465c47f | 2013-09-11 14:20:17 -0700 | [diff] [blame] | 2219 | pr_warn("Truncating oversized swap area, only using %luk out of %luk\n", |
Raymond Jennings | d6bbbd2 | 2013-09-11 14:20:16 -0700 | [diff] [blame] | 2220 | maxpages << (PAGE_SHIFT - 10), |
| 2221 | last_page << (PAGE_SHIFT - 10)); |
| 2222 | } |
| 2223 | if (maxpages > last_page) { |
| 2224 | maxpages = last_page + 1; |
Cesar Eduardo Barros | ca8bd38 | 2011-03-22 16:33:29 -0700 | [diff] [blame] | 2225 | /* p->max is an unsigned int: don't overflow it */ |
| 2226 | if ((unsigned int)maxpages == 0) |
| 2227 | maxpages = UINT_MAX; |
| 2228 | } |
| 2229 | p->highest_bit = maxpages - 1; |
| 2230 | |
| 2231 | if (!maxpages) |
Cesar Eduardo Barros | 3871902 | 2011-03-22 16:33:30 -0700 | [diff] [blame] | 2232 | return 0; |
Cesar Eduardo Barros | ca8bd38 | 2011-03-22 16:33:29 -0700 | [diff] [blame] | 2233 | swapfilepages = i_size_read(inode) >> PAGE_SHIFT; |
| 2234 | if (swapfilepages && maxpages > swapfilepages) { |
Andrew Morton | 465c47f | 2013-09-11 14:20:17 -0700 | [diff] [blame] | 2235 | pr_warn("Swap area shorter than signature indicates\n"); |
Cesar Eduardo Barros | 3871902 | 2011-03-22 16:33:30 -0700 | [diff] [blame] | 2236 | return 0; |
Cesar Eduardo Barros | ca8bd38 | 2011-03-22 16:33:29 -0700 | [diff] [blame] | 2237 | } |
| 2238 | if (swap_header->info.nr_badpages && S_ISREG(inode->i_mode)) |
Cesar Eduardo Barros | 3871902 | 2011-03-22 16:33:30 -0700 | [diff] [blame] | 2239 | return 0; |
Cesar Eduardo Barros | ca8bd38 | 2011-03-22 16:33:29 -0700 | [diff] [blame] | 2240 | if (swap_header->info.nr_badpages > MAX_SWAP_BADPAGES) |
Cesar Eduardo Barros | 3871902 | 2011-03-22 16:33:30 -0700 | [diff] [blame] | 2241 | return 0; |
Cesar Eduardo Barros | ca8bd38 | 2011-03-22 16:33:29 -0700 | [diff] [blame] | 2242 | |
| 2243 | return maxpages; |
Cesar Eduardo Barros | ca8bd38 | 2011-03-22 16:33:29 -0700 | [diff] [blame] | 2244 | } |
| 2245 | |
Cesar Eduardo Barros | 915d4d7 | 2011-03-22 16:33:32 -0700 | [diff] [blame] | 2246 | static int setup_swap_map_and_extents(struct swap_info_struct *p, |
| 2247 | union swap_header *swap_header, |
| 2248 | unsigned char *swap_map, |
Shaohua Li | 2a8f944 | 2013-09-11 14:20:28 -0700 | [diff] [blame] | 2249 | struct swap_cluster_info *cluster_info, |
Cesar Eduardo Barros | 915d4d7 | 2011-03-22 16:33:32 -0700 | [diff] [blame] | 2250 | unsigned long maxpages, |
| 2251 | sector_t *span) |
| 2252 | { |
| 2253 | int i; |
Cesar Eduardo Barros | 915d4d7 | 2011-03-22 16:33:32 -0700 | [diff] [blame] | 2254 | unsigned int nr_good_pages; |
| 2255 | int nr_extents; |
Shaohua Li | 2a8f944 | 2013-09-11 14:20:28 -0700 | [diff] [blame] | 2256 | unsigned long nr_clusters = DIV_ROUND_UP(maxpages, SWAPFILE_CLUSTER); |
| 2257 | unsigned long idx = p->cluster_next / SWAPFILE_CLUSTER; |
Cesar Eduardo Barros | 915d4d7 | 2011-03-22 16:33:32 -0700 | [diff] [blame] | 2258 | |
| 2259 | nr_good_pages = maxpages - 1; /* omit header page */ |
| 2260 | |
Shaohua Li | 2a8f944 | 2013-09-11 14:20:28 -0700 | [diff] [blame] | 2261 | cluster_set_null(&p->free_cluster_head); |
| 2262 | cluster_set_null(&p->free_cluster_tail); |
Shaohua Li | 815c2c5 | 2013-09-11 14:20:30 -0700 | [diff] [blame] | 2263 | cluster_set_null(&p->discard_cluster_head); |
| 2264 | cluster_set_null(&p->discard_cluster_tail); |
Shaohua Li | 2a8f944 | 2013-09-11 14:20:28 -0700 | [diff] [blame] | 2265 | |
Cesar Eduardo Barros | 915d4d7 | 2011-03-22 16:33:32 -0700 | [diff] [blame] | 2266 | for (i = 0; i < swap_header->info.nr_badpages; i++) { |
| 2267 | unsigned int page_nr = swap_header->info.badpages[i]; |
Cesar Eduardo Barros | bdb8e3f | 2011-03-22 16:33:33 -0700 | [diff] [blame] | 2268 | if (page_nr == 0 || page_nr > swap_header->info.last_page) |
| 2269 | return -EINVAL; |
Cesar Eduardo Barros | 915d4d7 | 2011-03-22 16:33:32 -0700 | [diff] [blame] | 2270 | if (page_nr < maxpages) { |
| 2271 | swap_map[page_nr] = SWAP_MAP_BAD; |
| 2272 | nr_good_pages--; |
Shaohua Li | 2a8f944 | 2013-09-11 14:20:28 -0700 | [diff] [blame] | 2273 | /* |
| 2274 | * Haven't marked the cluster free yet, no list |
| 2275 | * operation involved |
| 2276 | */ |
| 2277 | inc_cluster_info_page(p, cluster_info, page_nr); |
Cesar Eduardo Barros | 915d4d7 | 2011-03-22 16:33:32 -0700 | [diff] [blame] | 2278 | } |
| 2279 | } |
| 2280 | |
Shaohua Li | 2a8f944 | 2013-09-11 14:20:28 -0700 | [diff] [blame] | 2281 | /* Haven't marked the cluster free yet, no list operation involved */ |
| 2282 | for (i = maxpages; i < round_up(maxpages, SWAPFILE_CLUSTER); i++) |
| 2283 | inc_cluster_info_page(p, cluster_info, i); |
| 2284 | |
Cesar Eduardo Barros | 915d4d7 | 2011-03-22 16:33:32 -0700 | [diff] [blame] | 2285 | if (nr_good_pages) { |
| 2286 | swap_map[0] = SWAP_MAP_BAD; |
Shaohua Li | 2a8f944 | 2013-09-11 14:20:28 -0700 | [diff] [blame] | 2287 | /* |
| 2288 | * Not mark the cluster free yet, no list |
| 2289 | * operation involved |
| 2290 | */ |
| 2291 | inc_cluster_info_page(p, cluster_info, 0); |
Cesar Eduardo Barros | 915d4d7 | 2011-03-22 16:33:32 -0700 | [diff] [blame] | 2292 | p->max = maxpages; |
| 2293 | p->pages = nr_good_pages; |
| 2294 | nr_extents = setup_swap_extents(p, span); |
Cesar Eduardo Barros | bdb8e3f | 2011-03-22 16:33:33 -0700 | [diff] [blame] | 2295 | if (nr_extents < 0) |
| 2296 | return nr_extents; |
Cesar Eduardo Barros | 915d4d7 | 2011-03-22 16:33:32 -0700 | [diff] [blame] | 2297 | nr_good_pages = p->pages; |
| 2298 | } |
| 2299 | if (!nr_good_pages) { |
Andrew Morton | 465c47f | 2013-09-11 14:20:17 -0700 | [diff] [blame] | 2300 | pr_warn("Empty swap-file\n"); |
Cesar Eduardo Barros | bdb8e3f | 2011-03-22 16:33:33 -0700 | [diff] [blame] | 2301 | return -EINVAL; |
Cesar Eduardo Barros | 915d4d7 | 2011-03-22 16:33:32 -0700 | [diff] [blame] | 2302 | } |
| 2303 | |
Shaohua Li | 2a8f944 | 2013-09-11 14:20:28 -0700 | [diff] [blame] | 2304 | if (!cluster_info) |
| 2305 | return nr_extents; |
| 2306 | |
| 2307 | for (i = 0; i < nr_clusters; i++) { |
| 2308 | if (!cluster_count(&cluster_info[idx])) { |
| 2309 | cluster_set_flag(&cluster_info[idx], CLUSTER_FLAG_FREE); |
| 2310 | if (cluster_is_null(&p->free_cluster_head)) { |
| 2311 | cluster_set_next_flag(&p->free_cluster_head, |
| 2312 | idx, 0); |
| 2313 | cluster_set_next_flag(&p->free_cluster_tail, |
| 2314 | idx, 0); |
| 2315 | } else { |
| 2316 | unsigned int tail; |
| 2317 | |
| 2318 | tail = cluster_next(&p->free_cluster_tail); |
| 2319 | cluster_set_next(&cluster_info[tail], idx); |
| 2320 | cluster_set_next_flag(&p->free_cluster_tail, |
| 2321 | idx, 0); |
| 2322 | } |
| 2323 | } |
| 2324 | idx++; |
| 2325 | if (idx == nr_clusters) |
| 2326 | idx = 0; |
| 2327 | } |
Cesar Eduardo Barros | 915d4d7 | 2011-03-22 16:33:32 -0700 | [diff] [blame] | 2328 | return nr_extents; |
Cesar Eduardo Barros | 915d4d7 | 2011-03-22 16:33:32 -0700 | [diff] [blame] | 2329 | } |
| 2330 | |
Rafael Aquini | dcf6b7d | 2013-07-03 15:02:46 -0700 | [diff] [blame] | 2331 | /* |
| 2332 | * Helper to sys_swapon determining if a given swap |
| 2333 | * backing device queue supports DISCARD operations. |
| 2334 | */ |
| 2335 | static bool swap_discardable(struct swap_info_struct *si) |
| 2336 | { |
| 2337 | struct request_queue *q = bdev_get_queue(si->bdev); |
| 2338 | |
| 2339 | if (!q || !blk_queue_discard(q)) |
| 2340 | return false; |
| 2341 | |
| 2342 | return true; |
| 2343 | } |
| 2344 | |
Cesar Eduardo Barros | 53cbb24 | 2011-03-22 16:33:17 -0700 | [diff] [blame] | 2345 | SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags) |
| 2346 | { |
| 2347 | struct swap_info_struct *p; |
Jeff Layton | 91a27b2 | 2012-10-10 15:25:28 -0400 | [diff] [blame] | 2348 | struct filename *name; |
Cesar Eduardo Barros | 53cbb24 | 2011-03-22 16:33:17 -0700 | [diff] [blame] | 2349 | struct file *swap_file = NULL; |
| 2350 | struct address_space *mapping; |
Cesar Eduardo Barros | 4053154 | 2011-03-22 16:33:37 -0700 | [diff] [blame] | 2351 | int i; |
| 2352 | int prio; |
Cesar Eduardo Barros | 53cbb24 | 2011-03-22 16:33:17 -0700 | [diff] [blame] | 2353 | int error; |
| 2354 | union swap_header *swap_header; |
Cesar Eduardo Barros | 915d4d7 | 2011-03-22 16:33:32 -0700 | [diff] [blame] | 2355 | int nr_extents; |
Cesar Eduardo Barros | 53cbb24 | 2011-03-22 16:33:17 -0700 | [diff] [blame] | 2356 | sector_t span; |
| 2357 | unsigned long maxpages; |
Cesar Eduardo Barros | 53cbb24 | 2011-03-22 16:33:17 -0700 | [diff] [blame] | 2358 | unsigned char *swap_map = NULL; |
Shaohua Li | 2a8f944 | 2013-09-11 14:20:28 -0700 | [diff] [blame] | 2359 | struct swap_cluster_info *cluster_info = NULL; |
Dan Magenheimer | 38b5faf | 2012-04-09 17:08:06 -0600 | [diff] [blame] | 2360 | unsigned long *frontswap_map = NULL; |
Cesar Eduardo Barros | 53cbb24 | 2011-03-22 16:33:17 -0700 | [diff] [blame] | 2361 | struct page *page = NULL; |
| 2362 | struct inode *inode = NULL; |
Cesar Eduardo Barros | 53cbb24 | 2011-03-22 16:33:17 -0700 | [diff] [blame] | 2363 | |
Hugh Dickins | d15cab9 | 2012-03-28 14:42:42 -0700 | [diff] [blame] | 2364 | if (swap_flags & ~SWAP_FLAGS_VALID) |
| 2365 | return -EINVAL; |
| 2366 | |
Cesar Eduardo Barros | 53cbb24 | 2011-03-22 16:33:17 -0700 | [diff] [blame] | 2367 | if (!capable(CAP_SYS_ADMIN)) |
| 2368 | return -EPERM; |
| 2369 | |
| 2370 | p = alloc_swap_info(); |
Cesar Eduardo Barros | 2542e513 | 2011-03-22 16:33:18 -0700 | [diff] [blame] | 2371 | if (IS_ERR(p)) |
| 2372 | return PTR_ERR(p); |
Cesar Eduardo Barros | 53cbb24 | 2011-03-22 16:33:17 -0700 | [diff] [blame] | 2373 | |
Shaohua Li | 815c2c5 | 2013-09-11 14:20:30 -0700 | [diff] [blame] | 2374 | INIT_WORK(&p->discard_work, swap_discard_work); |
| 2375 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2376 | name = getname(specialfile); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2377 | if (IS_ERR(name)) { |
Cesar Eduardo Barros | 7de7fb6 | 2011-03-22 16:33:22 -0700 | [diff] [blame] | 2378 | error = PTR_ERR(name); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2379 | name = NULL; |
Cesar Eduardo Barros | bd69010 | 2011-03-22 16:33:25 -0700 | [diff] [blame] | 2380 | goto bad_swap; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2381 | } |
Jeff Layton | 669abf4 | 2012-10-10 16:43:10 -0400 | [diff] [blame] | 2382 | swap_file = file_open_name(name, O_RDWR|O_LARGEFILE, 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2383 | if (IS_ERR(swap_file)) { |
Cesar Eduardo Barros | 7de7fb6 | 2011-03-22 16:33:22 -0700 | [diff] [blame] | 2384 | error = PTR_ERR(swap_file); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2385 | swap_file = NULL; |
Cesar Eduardo Barros | bd69010 | 2011-03-22 16:33:25 -0700 | [diff] [blame] | 2386 | goto bad_swap; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2387 | } |
| 2388 | |
| 2389 | p->swap_file = swap_file; |
| 2390 | mapping = swap_file->f_mapping; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2391 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2392 | for (i = 0; i < nr_swapfiles; i++) { |
Hugh Dickins | efa90a9 | 2009-12-14 17:58:41 -0800 | [diff] [blame] | 2393 | struct swap_info_struct *q = swap_info[i]; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2394 | |
Cesar Eduardo Barros | e8e6c2e | 2011-03-22 16:33:16 -0700 | [diff] [blame] | 2395 | if (q == p || !q->swap_file) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2396 | continue; |
Cesar Eduardo Barros | 7de7fb6 | 2011-03-22 16:33:22 -0700 | [diff] [blame] | 2397 | if (mapping == q->swap_file->f_mapping) { |
| 2398 | error = -EBUSY; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2399 | goto bad_swap; |
Cesar Eduardo Barros | 7de7fb6 | 2011-03-22 16:33:22 -0700 | [diff] [blame] | 2400 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2401 | } |
| 2402 | |
Cesar Eduardo Barros | 2130781 | 2011-03-22 23:03:13 -0300 | [diff] [blame] | 2403 | inode = mapping->host; |
| 2404 | /* If S_ISREG(inode->i_mode) will do mutex_lock(&inode->i_mutex); */ |
Cesar Eduardo Barros | 4d0e1e1 | 2011-03-22 16:33:26 -0700 | [diff] [blame] | 2405 | error = claim_swapfile(p, inode); |
| 2406 | if (unlikely(error)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2407 | goto bad_swap; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2408 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2409 | /* |
| 2410 | * Read the swap header. |
| 2411 | */ |
| 2412 | if (!mapping->a_ops->readpage) { |
| 2413 | error = -EINVAL; |
| 2414 | goto bad_swap; |
| 2415 | } |
Pekka Enberg | 090d2b1 | 2006-06-23 02:05:08 -0700 | [diff] [blame] | 2416 | page = read_mapping_page(mapping, 0, swap_file); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2417 | if (IS_ERR(page)) { |
| 2418 | error = PTR_ERR(page); |
| 2419 | goto bad_swap; |
| 2420 | } |
Hugh Dickins | 81e3397 | 2009-01-06 14:39:49 -0800 | [diff] [blame] | 2421 | swap_header = kmap(page); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2422 | |
Cesar Eduardo Barros | ca8bd38 | 2011-03-22 16:33:29 -0700 | [diff] [blame] | 2423 | maxpages = read_swap_header(p, swap_header, inode); |
| 2424 | if (unlikely(!maxpages)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2425 | error = -EINVAL; |
| 2426 | goto bad_swap; |
| 2427 | } |
Hugh Dickins | 886bb7e | 2009-01-06 14:39:48 -0800 | [diff] [blame] | 2428 | |
Hugh Dickins | 81e3397 | 2009-01-06 14:39:49 -0800 | [diff] [blame] | 2429 | /* OK, set up the swap map and apply the bad block list */ |
Cesar Eduardo Barros | 803d0c83 | 2011-03-22 16:33:14 -0700 | [diff] [blame] | 2430 | swap_map = vzalloc(maxpages); |
Hugh Dickins | 81e3397 | 2009-01-06 14:39:49 -0800 | [diff] [blame] | 2431 | if (!swap_map) { |
| 2432 | error = -ENOMEM; |
| 2433 | goto bad_swap; |
| 2434 | } |
Shaohua Li | 2a8f944 | 2013-09-11 14:20:28 -0700 | [diff] [blame] | 2435 | if (p->bdev && blk_queue_nonrot(bdev_get_queue(p->bdev))) { |
| 2436 | p->flags |= SWP_SOLIDSTATE; |
| 2437 | /* |
| 2438 | * select a random position to start with to help wear leveling |
| 2439 | * SSD |
| 2440 | */ |
| 2441 | p->cluster_next = 1 + (prandom_u32() % p->highest_bit); |
| 2442 | |
| 2443 | cluster_info = vzalloc(DIV_ROUND_UP(maxpages, |
| 2444 | SWAPFILE_CLUSTER) * sizeof(*cluster_info)); |
| 2445 | if (!cluster_info) { |
| 2446 | error = -ENOMEM; |
| 2447 | goto bad_swap; |
| 2448 | } |
Shaohua Li | ebc2a1a | 2013-09-11 14:20:32 -0700 | [diff] [blame] | 2449 | p->percpu_cluster = alloc_percpu(struct percpu_cluster); |
| 2450 | if (!p->percpu_cluster) { |
| 2451 | error = -ENOMEM; |
| 2452 | goto bad_swap; |
| 2453 | } |
| 2454 | for_each_possible_cpu(i) { |
| 2455 | struct percpu_cluster *cluster; |
| 2456 | cluster = per_cpu_ptr(p->percpu_cluster, i); |
| 2457 | cluster_set_null(&cluster->index); |
| 2458 | } |
Shaohua Li | 2a8f944 | 2013-09-11 14:20:28 -0700 | [diff] [blame] | 2459 | } |
Hugh Dickins | 81e3397 | 2009-01-06 14:39:49 -0800 | [diff] [blame] | 2460 | |
Cesar Eduardo Barros | 1421ef3 | 2011-03-22 16:33:31 -0700 | [diff] [blame] | 2461 | error = swap_cgroup_swapon(p->type, maxpages); |
| 2462 | if (error) |
| 2463 | goto bad_swap; |
| 2464 | |
Cesar Eduardo Barros | 915d4d7 | 2011-03-22 16:33:32 -0700 | [diff] [blame] | 2465 | nr_extents = setup_swap_map_and_extents(p, swap_header, swap_map, |
Shaohua Li | 2a8f944 | 2013-09-11 14:20:28 -0700 | [diff] [blame] | 2466 | cluster_info, maxpages, &span); |
Cesar Eduardo Barros | 915d4d7 | 2011-03-22 16:33:32 -0700 | [diff] [blame] | 2467 | if (unlikely(nr_extents < 0)) { |
| 2468 | error = nr_extents; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2469 | goto bad_swap; |
| 2470 | } |
Dan Magenheimer | 38b5faf | 2012-04-09 17:08:06 -0600 | [diff] [blame] | 2471 | /* frontswap enabled? set up bit-per-page map for frontswap */ |
| 2472 | if (frontswap_enabled) |
Akinobu Mita | 7b57976 | 2013-06-12 14:05:08 -0700 | [diff] [blame] | 2473 | frontswap_map = vzalloc(BITS_TO_LONGS(maxpages) * sizeof(long)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2474 | |
Shaohua Li | 2a8f944 | 2013-09-11 14:20:28 -0700 | [diff] [blame] | 2475 | if (p->bdev &&(swap_flags & SWAP_FLAG_DISCARD) && swap_discardable(p)) { |
| 2476 | /* |
| 2477 | * When discard is enabled for swap with no particular |
| 2478 | * policy flagged, we set all swap discard flags here in |
| 2479 | * order to sustain backward compatibility with older |
| 2480 | * swapon(8) releases. |
| 2481 | */ |
| 2482 | p->flags |= (SWP_DISCARDABLE | SWP_AREA_DISCARD | |
| 2483 | SWP_PAGE_DISCARD); |
Rafael Aquini | dcf6b7d | 2013-07-03 15:02:46 -0700 | [diff] [blame] | 2484 | |
Shaohua Li | 2a8f944 | 2013-09-11 14:20:28 -0700 | [diff] [blame] | 2485 | /* |
| 2486 | * By flagging sys_swapon, a sysadmin can tell us to |
| 2487 | * either do single-time area discards only, or to just |
| 2488 | * perform discards for released swap page-clusters. |
| 2489 | * Now it's time to adjust the p->flags accordingly. |
| 2490 | */ |
| 2491 | if (swap_flags & SWAP_FLAG_DISCARD_ONCE) |
| 2492 | p->flags &= ~SWP_PAGE_DISCARD; |
| 2493 | else if (swap_flags & SWAP_FLAG_DISCARD_PAGES) |
| 2494 | p->flags &= ~SWP_AREA_DISCARD; |
Rafael Aquini | dcf6b7d | 2013-07-03 15:02:46 -0700 | [diff] [blame] | 2495 | |
Shaohua Li | 2a8f944 | 2013-09-11 14:20:28 -0700 | [diff] [blame] | 2496 | /* issue a swapon-time discard if it's still required */ |
| 2497 | if (p->flags & SWP_AREA_DISCARD) { |
| 2498 | int err = discard_swap(p); |
| 2499 | if (unlikely(err)) |
| 2500 | pr_err("swapon: discard_swap(%p): %d\n", |
| 2501 | p, err); |
Rafael Aquini | dcf6b7d | 2013-07-03 15:02:46 -0700 | [diff] [blame] | 2502 | } |
Hugh Dickins | 20137a4 | 2009-01-06 14:39:54 -0800 | [diff] [blame] | 2503 | } |
Hugh Dickins | 6a6ba83 | 2009-01-06 14:39:51 -0800 | [diff] [blame] | 2504 | |
Ingo Molnar | fc0abb1 | 2006-01-18 17:42:33 -0800 | [diff] [blame] | 2505 | mutex_lock(&swapon_mutex); |
Cesar Eduardo Barros | 4053154 | 2011-03-22 16:33:37 -0700 | [diff] [blame] | 2506 | prio = -1; |
Hugh Dickins | 78ecba0 | 2008-07-23 21:28:23 -0700 | [diff] [blame] | 2507 | if (swap_flags & SWAP_FLAG_PREFER) |
Cesar Eduardo Barros | 4053154 | 2011-03-22 16:33:37 -0700 | [diff] [blame] | 2508 | prio = |
Hugh Dickins | 78ecba0 | 2008-07-23 21:28:23 -0700 | [diff] [blame] | 2509 | (swap_flags & SWAP_FLAG_PRIO_MASK) >> SWAP_FLAG_PRIO_SHIFT; |
Shaohua Li | 2a8f944 | 2013-09-11 14:20:28 -0700 | [diff] [blame] | 2510 | enable_swap_info(p, prio, swap_map, cluster_info, frontswap_map); |
Cesar Eduardo Barros | c69dbfb | 2011-03-22 16:33:35 -0700 | [diff] [blame] | 2511 | |
Andrew Morton | 465c47f | 2013-09-11 14:20:17 -0700 | [diff] [blame] | 2512 | pr_info("Adding %uk swap on %s. " |
Rafael Aquini | dcf6b7d | 2013-07-03 15:02:46 -0700 | [diff] [blame] | 2513 | "Priority:%d extents:%d across:%lluk %s%s%s%s%s\n", |
Jeff Layton | 91a27b2 | 2012-10-10 15:25:28 -0400 | [diff] [blame] | 2514 | p->pages<<(PAGE_SHIFT-10), name->name, p->prio, |
Cesar Eduardo Barros | c69dbfb | 2011-03-22 16:33:35 -0700 | [diff] [blame] | 2515 | nr_extents, (unsigned long long)span<<(PAGE_SHIFT-10), |
| 2516 | (p->flags & SWP_SOLIDSTATE) ? "SS" : "", |
Dan Magenheimer | 38b5faf | 2012-04-09 17:08:06 -0600 | [diff] [blame] | 2517 | (p->flags & SWP_DISCARDABLE) ? "D" : "", |
Rafael Aquini | dcf6b7d | 2013-07-03 15:02:46 -0700 | [diff] [blame] | 2518 | (p->flags & SWP_AREA_DISCARD) ? "s" : "", |
| 2519 | (p->flags & SWP_PAGE_DISCARD) ? "c" : "", |
Dan Magenheimer | 38b5faf | 2012-04-09 17:08:06 -0600 | [diff] [blame] | 2520 | (frontswap_map) ? "FS" : ""); |
Cesar Eduardo Barros | c69dbfb | 2011-03-22 16:33:35 -0700 | [diff] [blame] | 2521 | |
Ingo Molnar | fc0abb1 | 2006-01-18 17:42:33 -0800 | [diff] [blame] | 2522 | mutex_unlock(&swapon_mutex); |
Kay Sievers | 66d7dd5 | 2010-10-26 14:22:06 -0700 | [diff] [blame] | 2523 | atomic_inc(&proc_poll_event); |
| 2524 | wake_up_interruptible(&proc_poll_wait); |
| 2525 | |
Cesar Eduardo Barros | 9b01c35 | 2011-03-22 16:33:24 -0700 | [diff] [blame] | 2526 | if (S_ISREG(inode->i_mode)) |
| 2527 | inode->i_flags |= S_SWAPFILE; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2528 | error = 0; |
| 2529 | goto out; |
| 2530 | bad_swap: |
Shaohua Li | ebc2a1a | 2013-09-11 14:20:32 -0700 | [diff] [blame] | 2531 | free_percpu(p->percpu_cluster); |
| 2532 | p->percpu_cluster = NULL; |
Cesar Eduardo Barros | bd69010 | 2011-03-22 16:33:25 -0700 | [diff] [blame] | 2533 | if (inode && S_ISBLK(inode->i_mode) && p->bdev) { |
Cesar Eduardo Barros | f2090d2 | 2011-03-22 16:33:23 -0700 | [diff] [blame] | 2534 | set_blocksize(p->bdev, p->old_block_size); |
| 2535 | blkdev_put(p->bdev, FMODE_READ | FMODE_WRITE | FMODE_EXCL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2536 | } |
Hugh Dickins | 4cd3bb1 | 2005-09-03 15:54:33 -0700 | [diff] [blame] | 2537 | destroy_swap_extents(p); |
Cesar Eduardo Barros | e8e6c2e | 2011-03-22 16:33:16 -0700 | [diff] [blame] | 2538 | swap_cgroup_swapoff(p->type); |
Hugh Dickins | 5d337b9 | 2005-09-03 15:54:41 -0700 | [diff] [blame] | 2539 | spin_lock(&swap_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2540 | p->swap_file = NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2541 | p->flags = 0; |
Hugh Dickins | 5d337b9 | 2005-09-03 15:54:41 -0700 | [diff] [blame] | 2542 | spin_unlock(&swap_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2543 | vfree(swap_map); |
Shaohua Li | 2a8f944 | 2013-09-11 14:20:28 -0700 | [diff] [blame] | 2544 | vfree(cluster_info); |
Mel Gorman | 52c5056 | 2011-03-22 16:30:08 -0700 | [diff] [blame] | 2545 | if (swap_file) { |
Cesar Eduardo Barros | 2130781 | 2011-03-22 23:03:13 -0300 | [diff] [blame] | 2546 | if (inode && S_ISREG(inode->i_mode)) { |
Mel Gorman | 52c5056 | 2011-03-22 16:30:08 -0700 | [diff] [blame] | 2547 | mutex_unlock(&inode->i_mutex); |
Cesar Eduardo Barros | 2130781 | 2011-03-22 23:03:13 -0300 | [diff] [blame] | 2548 | inode = NULL; |
| 2549 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2550 | filp_close(swap_file, NULL); |
Mel Gorman | 52c5056 | 2011-03-22 16:30:08 -0700 | [diff] [blame] | 2551 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2552 | out: |
| 2553 | if (page && !IS_ERR(page)) { |
| 2554 | kunmap(page); |
| 2555 | page_cache_release(page); |
| 2556 | } |
| 2557 | if (name) |
| 2558 | putname(name); |
Cesar Eduardo Barros | 9b01c35 | 2011-03-22 16:33:24 -0700 | [diff] [blame] | 2559 | if (inode && S_ISREG(inode->i_mode)) |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 2560 | mutex_unlock(&inode->i_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2561 | return error; |
| 2562 | } |
| 2563 | |
| 2564 | void si_swapinfo(struct sysinfo *val) |
| 2565 | { |
Hugh Dickins | efa90a9 | 2009-12-14 17:58:41 -0800 | [diff] [blame] | 2566 | unsigned int type; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2567 | unsigned long nr_to_be_unused = 0; |
| 2568 | |
Hugh Dickins | 5d337b9 | 2005-09-03 15:54:41 -0700 | [diff] [blame] | 2569 | spin_lock(&swap_lock); |
Hugh Dickins | efa90a9 | 2009-12-14 17:58:41 -0800 | [diff] [blame] | 2570 | for (type = 0; type < nr_swapfiles; type++) { |
| 2571 | struct swap_info_struct *si = swap_info[type]; |
| 2572 | |
| 2573 | if ((si->flags & SWP_USED) && !(si->flags & SWP_WRITEOK)) |
| 2574 | nr_to_be_unused += si->inuse_pages; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2575 | } |
Shaohua Li | ec8acf2 | 2013-02-22 16:34:38 -0800 | [diff] [blame] | 2576 | val->freeswap = atomic_long_read(&nr_swap_pages) + nr_to_be_unused; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2577 | val->totalswap = total_swap_pages + nr_to_be_unused; |
Hugh Dickins | 5d337b9 | 2005-09-03 15:54:41 -0700 | [diff] [blame] | 2578 | spin_unlock(&swap_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2579 | } |
| 2580 | |
| 2581 | /* |
| 2582 | * Verify that a swap entry is valid and increment its swap map count. |
| 2583 | * |
KAMEZAWA Hiroyuki | 355cfa7 | 2009-06-16 15:32:53 -0700 | [diff] [blame] | 2584 | * Returns error code in following case. |
| 2585 | * - success -> 0 |
| 2586 | * - swp_entry is invalid -> EINVAL |
| 2587 | * - swp_entry is migration entry -> EINVAL |
| 2588 | * - swap-cache reference is requested but there is already one. -> EEXIST |
| 2589 | * - swap-cache reference is requested but the entry is not used. -> ENOENT |
Hugh Dickins | 570a335b | 2009-12-14 17:58:46 -0800 | [diff] [blame] | 2590 | * - swap-mapped reference requested but needs continued swap count. -> ENOMEM |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2591 | */ |
Hugh Dickins | 8d69aae | 2009-12-14 17:58:45 -0800 | [diff] [blame] | 2592 | static int __swap_duplicate(swp_entry_t entry, unsigned char usage) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2593 | { |
Hugh Dickins | 73c34b6 | 2009-12-14 17:58:43 -0800 | [diff] [blame] | 2594 | struct swap_info_struct *p; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2595 | unsigned long offset, type; |
Hugh Dickins | 8d69aae | 2009-12-14 17:58:45 -0800 | [diff] [blame] | 2596 | unsigned char count; |
| 2597 | unsigned char has_cache; |
Hugh Dickins | 253d553 | 2009-12-14 17:58:44 -0800 | [diff] [blame] | 2598 | int err = -EINVAL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2599 | |
Andi Kleen | a7420aa | 2009-09-16 11:50:05 +0200 | [diff] [blame] | 2600 | if (non_swap_entry(entry)) |
Hugh Dickins | 253d553 | 2009-12-14 17:58:44 -0800 | [diff] [blame] | 2601 | goto out; |
Christoph Lameter | 0697212 | 2006-06-23 02:03:35 -0700 | [diff] [blame] | 2602 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2603 | type = swp_type(entry); |
| 2604 | if (type >= nr_swapfiles) |
| 2605 | goto bad_file; |
Hugh Dickins | efa90a9 | 2009-12-14 17:58:41 -0800 | [diff] [blame] | 2606 | p = swap_info[type]; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2607 | offset = swp_offset(entry); |
| 2608 | |
Shaohua Li | ec8acf2 | 2013-02-22 16:34:38 -0800 | [diff] [blame] | 2609 | spin_lock(&p->lock); |
KAMEZAWA Hiroyuki | 355cfa7 | 2009-06-16 15:32:53 -0700 | [diff] [blame] | 2610 | if (unlikely(offset >= p->max)) |
| 2611 | goto unlock_out; |
| 2612 | |
Hugh Dickins | 253d553 | 2009-12-14 17:58:44 -0800 | [diff] [blame] | 2613 | count = p->swap_map[offset]; |
Shaohua Li | edfe23d | 2013-09-11 14:20:31 -0700 | [diff] [blame] | 2614 | |
| 2615 | /* |
| 2616 | * swapin_readahead() doesn't check if a swap entry is valid, so the |
| 2617 | * swap entry could be SWAP_MAP_BAD. Check here with lock held. |
| 2618 | */ |
| 2619 | if (unlikely(swap_count(count) == SWAP_MAP_BAD)) { |
| 2620 | err = -ENOENT; |
| 2621 | goto unlock_out; |
| 2622 | } |
| 2623 | |
Hugh Dickins | 253d553 | 2009-12-14 17:58:44 -0800 | [diff] [blame] | 2624 | has_cache = count & SWAP_HAS_CACHE; |
| 2625 | count &= ~SWAP_HAS_CACHE; |
| 2626 | err = 0; |
KAMEZAWA Hiroyuki | 355cfa7 | 2009-06-16 15:32:53 -0700 | [diff] [blame] | 2627 | |
Hugh Dickins | 253d553 | 2009-12-14 17:58:44 -0800 | [diff] [blame] | 2628 | if (usage == SWAP_HAS_CACHE) { |
KAMEZAWA Hiroyuki | 355cfa7 | 2009-06-16 15:32:53 -0700 | [diff] [blame] | 2629 | |
| 2630 | /* set SWAP_HAS_CACHE if there is no cache and entry is used */ |
Hugh Dickins | 253d553 | 2009-12-14 17:58:44 -0800 | [diff] [blame] | 2631 | if (!has_cache && count) |
| 2632 | has_cache = SWAP_HAS_CACHE; |
| 2633 | else if (has_cache) /* someone else added cache */ |
| 2634 | err = -EEXIST; |
| 2635 | else /* no users remaining */ |
| 2636 | err = -ENOENT; |
KAMEZAWA Hiroyuki | 355cfa7 | 2009-06-16 15:32:53 -0700 | [diff] [blame] | 2637 | |
| 2638 | } else if (count || has_cache) { |
Hugh Dickins | 253d553 | 2009-12-14 17:58:44 -0800 | [diff] [blame] | 2639 | |
Hugh Dickins | 570a335b | 2009-12-14 17:58:46 -0800 | [diff] [blame] | 2640 | if ((count & ~COUNT_CONTINUED) < SWAP_MAP_MAX) |
| 2641 | count += usage; |
| 2642 | else if ((count & ~COUNT_CONTINUED) > SWAP_MAP_MAX) |
Hugh Dickins | 253d553 | 2009-12-14 17:58:44 -0800 | [diff] [blame] | 2643 | err = -EINVAL; |
Hugh Dickins | 570a335b | 2009-12-14 17:58:46 -0800 | [diff] [blame] | 2644 | else if (swap_count_continued(p, offset, count)) |
| 2645 | count = COUNT_CONTINUED; |
| 2646 | else |
| 2647 | err = -ENOMEM; |
KAMEZAWA Hiroyuki | 355cfa7 | 2009-06-16 15:32:53 -0700 | [diff] [blame] | 2648 | } else |
Hugh Dickins | 253d553 | 2009-12-14 17:58:44 -0800 | [diff] [blame] | 2649 | err = -ENOENT; /* unused swap entry */ |
| 2650 | |
| 2651 | p->swap_map[offset] = count | has_cache; |
| 2652 | |
KAMEZAWA Hiroyuki | 355cfa7 | 2009-06-16 15:32:53 -0700 | [diff] [blame] | 2653 | unlock_out: |
Shaohua Li | ec8acf2 | 2013-02-22 16:34:38 -0800 | [diff] [blame] | 2654 | spin_unlock(&p->lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2655 | out: |
Hugh Dickins | 253d553 | 2009-12-14 17:58:44 -0800 | [diff] [blame] | 2656 | return err; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2657 | |
| 2658 | bad_file: |
Andrew Morton | 465c47f | 2013-09-11 14:20:17 -0700 | [diff] [blame] | 2659 | pr_err("swap_dup: %s%08lx\n", Bad_file, entry.val); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2660 | goto out; |
| 2661 | } |
Hugh Dickins | 253d553 | 2009-12-14 17:58:44 -0800 | [diff] [blame] | 2662 | |
KAMEZAWA Hiroyuki | 355cfa7 | 2009-06-16 15:32:53 -0700 | [diff] [blame] | 2663 | /* |
Hugh Dickins | aaa4686 | 2009-12-14 17:58:47 -0800 | [diff] [blame] | 2664 | * Help swapoff by noting that swap entry belongs to shmem/tmpfs |
| 2665 | * (in which case its reference count is never incremented). |
| 2666 | */ |
| 2667 | void swap_shmem_alloc(swp_entry_t entry) |
| 2668 | { |
| 2669 | __swap_duplicate(entry, SWAP_MAP_SHMEM); |
| 2670 | } |
| 2671 | |
| 2672 | /* |
Hugh Dickins | 08259d5 | 2010-03-05 13:42:25 -0800 | [diff] [blame] | 2673 | * Increase reference count of swap entry by 1. |
| 2674 | * Returns 0 for success, or -ENOMEM if a swap_count_continuation is required |
| 2675 | * but could not be atomically allocated. Returns 0, just as if it succeeded, |
| 2676 | * if __swap_duplicate() fails for another reason (-EINVAL or -ENOENT), which |
| 2677 | * might occur if a page table entry has got corrupted. |
KAMEZAWA Hiroyuki | 355cfa7 | 2009-06-16 15:32:53 -0700 | [diff] [blame] | 2678 | */ |
Hugh Dickins | 570a335b | 2009-12-14 17:58:46 -0800 | [diff] [blame] | 2679 | int swap_duplicate(swp_entry_t entry) |
KAMEZAWA Hiroyuki | 355cfa7 | 2009-06-16 15:32:53 -0700 | [diff] [blame] | 2680 | { |
Hugh Dickins | 570a335b | 2009-12-14 17:58:46 -0800 | [diff] [blame] | 2681 | int err = 0; |
| 2682 | |
| 2683 | while (!err && __swap_duplicate(entry, 1) == -ENOMEM) |
| 2684 | err = add_swap_count_continuation(entry, GFP_ATOMIC); |
| 2685 | return err; |
KAMEZAWA Hiroyuki | 355cfa7 | 2009-06-16 15:32:53 -0700 | [diff] [blame] | 2686 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2687 | |
KAMEZAWA Hiroyuki | cb4b86b | 2009-06-16 15:32:52 -0700 | [diff] [blame] | 2688 | /* |
KAMEZAWA Hiroyuki | 355cfa7 | 2009-06-16 15:32:53 -0700 | [diff] [blame] | 2689 | * @entry: swap entry for which we allocate swap cache. |
| 2690 | * |
Hugh Dickins | 73c34b6 | 2009-12-14 17:58:43 -0800 | [diff] [blame] | 2691 | * Called when allocating swap cache for existing swap entry, |
KAMEZAWA Hiroyuki | 355cfa7 | 2009-06-16 15:32:53 -0700 | [diff] [blame] | 2692 | * This can return error codes. Returns 0 at success. |
| 2693 | * -EBUSY means there is a swap cache. |
| 2694 | * Note: return code is different from swap_duplicate(). |
KAMEZAWA Hiroyuki | cb4b86b | 2009-06-16 15:32:52 -0700 | [diff] [blame] | 2695 | */ |
| 2696 | int swapcache_prepare(swp_entry_t entry) |
| 2697 | { |
Hugh Dickins | 253d553 | 2009-12-14 17:58:44 -0800 | [diff] [blame] | 2698 | return __swap_duplicate(entry, SWAP_HAS_CACHE); |
KAMEZAWA Hiroyuki | cb4b86b | 2009-06-16 15:32:52 -0700 | [diff] [blame] | 2699 | } |
| 2700 | |
Mel Gorman | f981c59 | 2012-07-31 16:44:47 -0700 | [diff] [blame] | 2701 | struct swap_info_struct *page_swap_info(struct page *page) |
| 2702 | { |
| 2703 | swp_entry_t swap = { .val = page_private(page) }; |
| 2704 | BUG_ON(!PageSwapCache(page)); |
| 2705 | return swap_info[swp_type(swap)]; |
| 2706 | } |
| 2707 | |
| 2708 | /* |
| 2709 | * out-of-line __page_file_ methods to avoid include hell. |
| 2710 | */ |
| 2711 | struct address_space *__page_file_mapping(struct page *page) |
| 2712 | { |
Sasha Levin | 309381fea | 2014-01-23 15:52:54 -0800 | [diff] [blame] | 2713 | VM_BUG_ON_PAGE(!PageSwapCache(page), page); |
Mel Gorman | f981c59 | 2012-07-31 16:44:47 -0700 | [diff] [blame] | 2714 | return page_swap_info(page)->swap_file->f_mapping; |
| 2715 | } |
| 2716 | EXPORT_SYMBOL_GPL(__page_file_mapping); |
| 2717 | |
| 2718 | pgoff_t __page_file_index(struct page *page) |
| 2719 | { |
| 2720 | swp_entry_t swap = { .val = page_private(page) }; |
Sasha Levin | 309381fea | 2014-01-23 15:52:54 -0800 | [diff] [blame] | 2721 | VM_BUG_ON_PAGE(!PageSwapCache(page), page); |
Mel Gorman | f981c59 | 2012-07-31 16:44:47 -0700 | [diff] [blame] | 2722 | return swp_offset(swap); |
| 2723 | } |
| 2724 | EXPORT_SYMBOL_GPL(__page_file_index); |
| 2725 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2726 | /* |
Hugh Dickins | 570a335b | 2009-12-14 17:58:46 -0800 | [diff] [blame] | 2727 | * add_swap_count_continuation - called when a swap count is duplicated |
| 2728 | * beyond SWAP_MAP_MAX, it allocates a new page and links that to the entry's |
| 2729 | * page of the original vmalloc'ed swap_map, to hold the continuation count |
| 2730 | * (for that entry and for its neighbouring PAGE_SIZE swap entries). Called |
| 2731 | * again when count is duplicated beyond SWAP_MAP_MAX * SWAP_CONT_MAX, etc. |
| 2732 | * |
| 2733 | * These continuation pages are seldom referenced: the common paths all work |
| 2734 | * on the original swap_map, only referring to a continuation page when the |
| 2735 | * low "digit" of a count is incremented or decremented through SWAP_MAP_MAX. |
| 2736 | * |
| 2737 | * add_swap_count_continuation(, GFP_ATOMIC) can be called while holding |
| 2738 | * page table locks; if it fails, add_swap_count_continuation(, GFP_KERNEL) |
| 2739 | * can be called after dropping locks. |
| 2740 | */ |
| 2741 | int add_swap_count_continuation(swp_entry_t entry, gfp_t gfp_mask) |
| 2742 | { |
| 2743 | struct swap_info_struct *si; |
| 2744 | struct page *head; |
| 2745 | struct page *page; |
| 2746 | struct page *list_page; |
| 2747 | pgoff_t offset; |
| 2748 | unsigned char count; |
| 2749 | |
| 2750 | /* |
| 2751 | * When debugging, it's easier to use __GFP_ZERO here; but it's better |
| 2752 | * for latency not to zero a page while GFP_ATOMIC and holding locks. |
| 2753 | */ |
| 2754 | page = alloc_page(gfp_mask | __GFP_HIGHMEM); |
| 2755 | |
| 2756 | si = swap_info_get(entry); |
| 2757 | if (!si) { |
| 2758 | /* |
| 2759 | * An acceptable race has occurred since the failing |
| 2760 | * __swap_duplicate(): the swap entry has been freed, |
| 2761 | * perhaps even the whole swap_map cleared for swapoff. |
| 2762 | */ |
| 2763 | goto outer; |
| 2764 | } |
| 2765 | |
| 2766 | offset = swp_offset(entry); |
| 2767 | count = si->swap_map[offset] & ~SWAP_HAS_CACHE; |
| 2768 | |
| 2769 | if ((count & ~COUNT_CONTINUED) != SWAP_MAP_MAX) { |
| 2770 | /* |
| 2771 | * The higher the swap count, the more likely it is that tasks |
| 2772 | * will race to add swap count continuation: we need to avoid |
| 2773 | * over-provisioning. |
| 2774 | */ |
| 2775 | goto out; |
| 2776 | } |
| 2777 | |
| 2778 | if (!page) { |
Shaohua Li | ec8acf2 | 2013-02-22 16:34:38 -0800 | [diff] [blame] | 2779 | spin_unlock(&si->lock); |
Hugh Dickins | 570a335b | 2009-12-14 17:58:46 -0800 | [diff] [blame] | 2780 | return -ENOMEM; |
| 2781 | } |
| 2782 | |
| 2783 | /* |
| 2784 | * We are fortunate that although vmalloc_to_page uses pte_offset_map, |
Seth Jennings | 2de1a7e | 2013-11-12 15:07:46 -0800 | [diff] [blame] | 2785 | * no architecture is using highmem pages for kernel page tables: so it |
| 2786 | * will not corrupt the GFP_ATOMIC caller's atomic page table kmaps. |
Hugh Dickins | 570a335b | 2009-12-14 17:58:46 -0800 | [diff] [blame] | 2787 | */ |
| 2788 | head = vmalloc_to_page(si->swap_map + offset); |
| 2789 | offset &= ~PAGE_MASK; |
| 2790 | |
| 2791 | /* |
| 2792 | * Page allocation does not initialize the page's lru field, |
| 2793 | * but it does always reset its private field. |
| 2794 | */ |
| 2795 | if (!page_private(head)) { |
| 2796 | BUG_ON(count & COUNT_CONTINUED); |
| 2797 | INIT_LIST_HEAD(&head->lru); |
| 2798 | set_page_private(head, SWP_CONTINUED); |
| 2799 | si->flags |= SWP_CONTINUED; |
| 2800 | } |
| 2801 | |
| 2802 | list_for_each_entry(list_page, &head->lru, lru) { |
| 2803 | unsigned char *map; |
| 2804 | |
| 2805 | /* |
| 2806 | * If the previous map said no continuation, but we've found |
| 2807 | * a continuation page, free our allocation and use this one. |
| 2808 | */ |
| 2809 | if (!(count & COUNT_CONTINUED)) |
| 2810 | goto out; |
| 2811 | |
Cong Wang | 9b04c5f | 2011-11-25 23:14:39 +0800 | [diff] [blame] | 2812 | map = kmap_atomic(list_page) + offset; |
Hugh Dickins | 570a335b | 2009-12-14 17:58:46 -0800 | [diff] [blame] | 2813 | count = *map; |
Cong Wang | 9b04c5f | 2011-11-25 23:14:39 +0800 | [diff] [blame] | 2814 | kunmap_atomic(map); |
Hugh Dickins | 570a335b | 2009-12-14 17:58:46 -0800 | [diff] [blame] | 2815 | |
| 2816 | /* |
| 2817 | * If this continuation count now has some space in it, |
| 2818 | * free our allocation and use this one. |
| 2819 | */ |
| 2820 | if ((count & ~COUNT_CONTINUED) != SWAP_CONT_MAX) |
| 2821 | goto out; |
| 2822 | } |
| 2823 | |
| 2824 | list_add_tail(&page->lru, &head->lru); |
| 2825 | page = NULL; /* now it's attached, don't free it */ |
| 2826 | out: |
Shaohua Li | ec8acf2 | 2013-02-22 16:34:38 -0800 | [diff] [blame] | 2827 | spin_unlock(&si->lock); |
Hugh Dickins | 570a335b | 2009-12-14 17:58:46 -0800 | [diff] [blame] | 2828 | outer: |
| 2829 | if (page) |
| 2830 | __free_page(page); |
| 2831 | return 0; |
| 2832 | } |
| 2833 | |
| 2834 | /* |
| 2835 | * swap_count_continued - when the original swap_map count is incremented |
| 2836 | * from SWAP_MAP_MAX, check if there is already a continuation page to carry |
| 2837 | * into, carry if so, or else fail until a new continuation page is allocated; |
| 2838 | * when the original swap_map count is decremented from 0 with continuation, |
| 2839 | * borrow from the continuation and report whether it still holds more. |
| 2840 | * Called while __swap_duplicate() or swap_entry_free() holds swap_lock. |
| 2841 | */ |
| 2842 | static bool swap_count_continued(struct swap_info_struct *si, |
| 2843 | pgoff_t offset, unsigned char count) |
| 2844 | { |
| 2845 | struct page *head; |
| 2846 | struct page *page; |
| 2847 | unsigned char *map; |
| 2848 | |
| 2849 | head = vmalloc_to_page(si->swap_map + offset); |
| 2850 | if (page_private(head) != SWP_CONTINUED) { |
| 2851 | BUG_ON(count & COUNT_CONTINUED); |
| 2852 | return false; /* need to add count continuation */ |
| 2853 | } |
| 2854 | |
| 2855 | offset &= ~PAGE_MASK; |
| 2856 | page = list_entry(head->lru.next, struct page, lru); |
Cong Wang | 9b04c5f | 2011-11-25 23:14:39 +0800 | [diff] [blame] | 2857 | map = kmap_atomic(page) + offset; |
Hugh Dickins | 570a335b | 2009-12-14 17:58:46 -0800 | [diff] [blame] | 2858 | |
| 2859 | if (count == SWAP_MAP_MAX) /* initial increment from swap_map */ |
| 2860 | goto init_map; /* jump over SWAP_CONT_MAX checks */ |
| 2861 | |
| 2862 | if (count == (SWAP_MAP_MAX | COUNT_CONTINUED)) { /* incrementing */ |
| 2863 | /* |
| 2864 | * Think of how you add 1 to 999 |
| 2865 | */ |
| 2866 | while (*map == (SWAP_CONT_MAX | COUNT_CONTINUED)) { |
Cong Wang | 9b04c5f | 2011-11-25 23:14:39 +0800 | [diff] [blame] | 2867 | kunmap_atomic(map); |
Hugh Dickins | 570a335b | 2009-12-14 17:58:46 -0800 | [diff] [blame] | 2868 | page = list_entry(page->lru.next, struct page, lru); |
| 2869 | BUG_ON(page == head); |
Cong Wang | 9b04c5f | 2011-11-25 23:14:39 +0800 | [diff] [blame] | 2870 | map = kmap_atomic(page) + offset; |
Hugh Dickins | 570a335b | 2009-12-14 17:58:46 -0800 | [diff] [blame] | 2871 | } |
| 2872 | if (*map == SWAP_CONT_MAX) { |
Cong Wang | 9b04c5f | 2011-11-25 23:14:39 +0800 | [diff] [blame] | 2873 | kunmap_atomic(map); |
Hugh Dickins | 570a335b | 2009-12-14 17:58:46 -0800 | [diff] [blame] | 2874 | page = list_entry(page->lru.next, struct page, lru); |
| 2875 | if (page == head) |
| 2876 | return false; /* add count continuation */ |
Cong Wang | 9b04c5f | 2011-11-25 23:14:39 +0800 | [diff] [blame] | 2877 | map = kmap_atomic(page) + offset; |
Hugh Dickins | 570a335b | 2009-12-14 17:58:46 -0800 | [diff] [blame] | 2878 | init_map: *map = 0; /* we didn't zero the page */ |
| 2879 | } |
| 2880 | *map += 1; |
Cong Wang | 9b04c5f | 2011-11-25 23:14:39 +0800 | [diff] [blame] | 2881 | kunmap_atomic(map); |
Hugh Dickins | 570a335b | 2009-12-14 17:58:46 -0800 | [diff] [blame] | 2882 | page = list_entry(page->lru.prev, struct page, lru); |
| 2883 | while (page != head) { |
Cong Wang | 9b04c5f | 2011-11-25 23:14:39 +0800 | [diff] [blame] | 2884 | map = kmap_atomic(page) + offset; |
Hugh Dickins | 570a335b | 2009-12-14 17:58:46 -0800 | [diff] [blame] | 2885 | *map = COUNT_CONTINUED; |
Cong Wang | 9b04c5f | 2011-11-25 23:14:39 +0800 | [diff] [blame] | 2886 | kunmap_atomic(map); |
Hugh Dickins | 570a335b | 2009-12-14 17:58:46 -0800 | [diff] [blame] | 2887 | page = list_entry(page->lru.prev, struct page, lru); |
| 2888 | } |
| 2889 | return true; /* incremented */ |
| 2890 | |
| 2891 | } else { /* decrementing */ |
| 2892 | /* |
| 2893 | * Think of how you subtract 1 from 1000 |
| 2894 | */ |
| 2895 | BUG_ON(count != COUNT_CONTINUED); |
| 2896 | while (*map == COUNT_CONTINUED) { |
Cong Wang | 9b04c5f | 2011-11-25 23:14:39 +0800 | [diff] [blame] | 2897 | kunmap_atomic(map); |
Hugh Dickins | 570a335b | 2009-12-14 17:58:46 -0800 | [diff] [blame] | 2898 | page = list_entry(page->lru.next, struct page, lru); |
| 2899 | BUG_ON(page == head); |
Cong Wang | 9b04c5f | 2011-11-25 23:14:39 +0800 | [diff] [blame] | 2900 | map = kmap_atomic(page) + offset; |
Hugh Dickins | 570a335b | 2009-12-14 17:58:46 -0800 | [diff] [blame] | 2901 | } |
| 2902 | BUG_ON(*map == 0); |
| 2903 | *map -= 1; |
| 2904 | if (*map == 0) |
| 2905 | count = 0; |
Cong Wang | 9b04c5f | 2011-11-25 23:14:39 +0800 | [diff] [blame] | 2906 | kunmap_atomic(map); |
Hugh Dickins | 570a335b | 2009-12-14 17:58:46 -0800 | [diff] [blame] | 2907 | page = list_entry(page->lru.prev, struct page, lru); |
| 2908 | while (page != head) { |
Cong Wang | 9b04c5f | 2011-11-25 23:14:39 +0800 | [diff] [blame] | 2909 | map = kmap_atomic(page) + offset; |
Hugh Dickins | 570a335b | 2009-12-14 17:58:46 -0800 | [diff] [blame] | 2910 | *map = SWAP_CONT_MAX | count; |
| 2911 | count = COUNT_CONTINUED; |
Cong Wang | 9b04c5f | 2011-11-25 23:14:39 +0800 | [diff] [blame] | 2912 | kunmap_atomic(map); |
Hugh Dickins | 570a335b | 2009-12-14 17:58:46 -0800 | [diff] [blame] | 2913 | page = list_entry(page->lru.prev, struct page, lru); |
| 2914 | } |
| 2915 | return count == COUNT_CONTINUED; |
| 2916 | } |
| 2917 | } |
| 2918 | |
| 2919 | /* |
| 2920 | * free_swap_count_continuations - swapoff free all the continuation pages |
| 2921 | * appended to the swap_map, after swap_map is quiesced, before vfree'ing it. |
| 2922 | */ |
| 2923 | static void free_swap_count_continuations(struct swap_info_struct *si) |
| 2924 | { |
| 2925 | pgoff_t offset; |
| 2926 | |
| 2927 | for (offset = 0; offset < si->max; offset += PAGE_SIZE) { |
| 2928 | struct page *head; |
| 2929 | head = vmalloc_to_page(si->swap_map + offset); |
| 2930 | if (page_private(head)) { |
| 2931 | struct list_head *this, *next; |
| 2932 | list_for_each_safe(this, next, &head->lru) { |
| 2933 | struct page *page; |
| 2934 | page = list_entry(this, struct page, lru); |
| 2935 | list_del(this); |
| 2936 | __free_page(page); |
| 2937 | } |
| 2938 | } |
| 2939 | } |
| 2940 | } |