Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | #ifndef _LINUX_PAGEMAP_H |
| 2 | #define _LINUX_PAGEMAP_H |
| 3 | |
| 4 | /* |
| 5 | * Copyright 1995 Linus Torvalds |
| 6 | */ |
| 7 | #include <linux/mm.h> |
| 8 | #include <linux/fs.h> |
| 9 | #include <linux/list.h> |
| 10 | #include <linux/highmem.h> |
| 11 | #include <linux/compiler.h> |
| 12 | #include <asm/uaccess.h> |
| 13 | #include <linux/gfp.h> |
Guillaume Chazarain | 3e9f45b | 2007-05-08 00:23:25 -0700 | [diff] [blame] | 14 | #include <linux/bitops.h> |
Nick Piggin | e286781 | 2008-07-25 19:45:30 -0700 | [diff] [blame] | 15 | #include <linux/hardirq.h> /* for in_interrupt() */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 16 | |
| 17 | /* |
| 18 | * Bits in mapping->flags. The lower __GFP_BITS_SHIFT bits are the page |
| 19 | * allocation mode flags. |
| 20 | */ |
Lee Schermerhorn | 9a896c9 | 2009-04-02 16:56:45 -0700 | [diff] [blame] | 21 | enum mapping_flags { |
| 22 | AS_EIO = __GFP_BITS_SHIFT + 0, /* IO error on async write */ |
| 23 | AS_ENOSPC = __GFP_BITS_SHIFT + 1, /* ENOSPC on async write */ |
| 24 | AS_MM_ALL_LOCKS = __GFP_BITS_SHIFT + 2, /* under mm_take_all_locks() */ |
| 25 | #ifdef CONFIG_UNEVICTABLE_LRU |
| 26 | AS_UNEVICTABLE = __GFP_BITS_SHIFT + 3, /* e.g., ramdisk, SHM_LOCK */ |
| 27 | #endif |
| 28 | }; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 29 | |
Guillaume Chazarain | 3e9f45b | 2007-05-08 00:23:25 -0700 | [diff] [blame] | 30 | static inline void mapping_set_error(struct address_space *mapping, int error) |
| 31 | { |
Andrew Morton | 2185e69 | 2008-07-23 21:27:19 -0700 | [diff] [blame] | 32 | if (unlikely(error)) { |
Guillaume Chazarain | 3e9f45b | 2007-05-08 00:23:25 -0700 | [diff] [blame] | 33 | if (error == -ENOSPC) |
| 34 | set_bit(AS_ENOSPC, &mapping->flags); |
| 35 | else |
| 36 | set_bit(AS_EIO, &mapping->flags); |
| 37 | } |
| 38 | } |
| 39 | |
Lee Schermerhorn | ba9ddf4 | 2008-10-18 20:26:42 -0700 | [diff] [blame] | 40 | #ifdef CONFIG_UNEVICTABLE_LRU |
Lee Schermerhorn | ba9ddf4 | 2008-10-18 20:26:42 -0700 | [diff] [blame] | 41 | |
| 42 | static inline void mapping_set_unevictable(struct address_space *mapping) |
| 43 | { |
| 44 | set_bit(AS_UNEVICTABLE, &mapping->flags); |
| 45 | } |
| 46 | |
Lee Schermerhorn | 89e004ea | 2008-10-18 20:26:43 -0700 | [diff] [blame] | 47 | static inline void mapping_clear_unevictable(struct address_space *mapping) |
| 48 | { |
| 49 | clear_bit(AS_UNEVICTABLE, &mapping->flags); |
| 50 | } |
| 51 | |
Lee Schermerhorn | ba9ddf4 | 2008-10-18 20:26:42 -0700 | [diff] [blame] | 52 | static inline int mapping_unevictable(struct address_space *mapping) |
| 53 | { |
Lee Schermerhorn | 89e004ea | 2008-10-18 20:26:43 -0700 | [diff] [blame] | 54 | if (likely(mapping)) |
| 55 | return test_bit(AS_UNEVICTABLE, &mapping->flags); |
| 56 | return !!mapping; |
Lee Schermerhorn | ba9ddf4 | 2008-10-18 20:26:42 -0700 | [diff] [blame] | 57 | } |
| 58 | #else |
| 59 | static inline void mapping_set_unevictable(struct address_space *mapping) { } |
Lee Schermerhorn | 89e004ea | 2008-10-18 20:26:43 -0700 | [diff] [blame] | 60 | static inline void mapping_clear_unevictable(struct address_space *mapping) { } |
Lee Schermerhorn | ba9ddf4 | 2008-10-18 20:26:42 -0700 | [diff] [blame] | 61 | static inline int mapping_unevictable(struct address_space *mapping) |
| 62 | { |
| 63 | return 0; |
| 64 | } |
| 65 | #endif |
| 66 | |
Al Viro | dd0fc66 | 2005-10-07 07:46:04 +0100 | [diff] [blame] | 67 | static inline gfp_t mapping_gfp_mask(struct address_space * mapping) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 68 | { |
Al Viro | 260b236 | 2005-10-21 03:22:44 -0400 | [diff] [blame] | 69 | return (__force gfp_t)mapping->flags & __GFP_BITS_MASK; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 70 | } |
| 71 | |
| 72 | /* |
| 73 | * This is non-atomic. Only to be used before the mapping is activated. |
| 74 | * Probably needs a barrier... |
| 75 | */ |
Al Viro | 260b236 | 2005-10-21 03:22:44 -0400 | [diff] [blame] | 76 | static inline void mapping_set_gfp_mask(struct address_space *m, gfp_t mask) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 77 | { |
Al Viro | 260b236 | 2005-10-21 03:22:44 -0400 | [diff] [blame] | 78 | m->flags = (m->flags & ~(__force unsigned long)__GFP_BITS_MASK) | |
| 79 | (__force unsigned long)mask; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 80 | } |
| 81 | |
| 82 | /* |
| 83 | * The page cache can done in larger chunks than |
| 84 | * one page, because it allows for more efficient |
| 85 | * throughput (it can then be mapped into user |
| 86 | * space in smaller chunks for same flexibility). |
| 87 | * |
| 88 | * Or rather, it _will_ be done in larger chunks. |
| 89 | */ |
| 90 | #define PAGE_CACHE_SHIFT PAGE_SHIFT |
| 91 | #define PAGE_CACHE_SIZE PAGE_SIZE |
| 92 | #define PAGE_CACHE_MASK PAGE_MASK |
| 93 | #define PAGE_CACHE_ALIGN(addr) (((addr)+PAGE_CACHE_SIZE-1)&PAGE_CACHE_MASK) |
| 94 | |
| 95 | #define page_cache_get(page) get_page(page) |
| 96 | #define page_cache_release(page) put_page(page) |
| 97 | void release_pages(struct page **pages, int nr, int cold); |
| 98 | |
Nick Piggin | e286781 | 2008-07-25 19:45:30 -0700 | [diff] [blame] | 99 | /* |
| 100 | * speculatively take a reference to a page. |
| 101 | * If the page is free (_count == 0), then _count is untouched, and 0 |
| 102 | * is returned. Otherwise, _count is incremented by 1 and 1 is returned. |
| 103 | * |
| 104 | * This function must be called inside the same rcu_read_lock() section as has |
| 105 | * been used to lookup the page in the pagecache radix-tree (or page table): |
| 106 | * this allows allocators to use a synchronize_rcu() to stabilize _count. |
| 107 | * |
| 108 | * Unless an RCU grace period has passed, the count of all pages coming out |
| 109 | * of the allocator must be considered unstable. page_count may return higher |
| 110 | * than expected, and put_page must be able to do the right thing when the |
| 111 | * page has been finished with, no matter what it is subsequently allocated |
| 112 | * for (because put_page is what is used here to drop an invalid speculative |
| 113 | * reference). |
| 114 | * |
| 115 | * This is the interesting part of the lockless pagecache (and lockless |
| 116 | * get_user_pages) locking protocol, where the lookup-side (eg. find_get_page) |
| 117 | * has the following pattern: |
| 118 | * 1. find page in radix tree |
| 119 | * 2. conditionally increment refcount |
| 120 | * 3. check the page is still in pagecache (if no, goto 1) |
| 121 | * |
| 122 | * Remove-side that cares about stability of _count (eg. reclaim) has the |
| 123 | * following (with tree_lock held for write): |
| 124 | * A. atomically check refcount is correct and set it to 0 (atomic_cmpxchg) |
| 125 | * B. remove page from pagecache |
| 126 | * C. free the page |
| 127 | * |
| 128 | * There are 2 critical interleavings that matter: |
| 129 | * - 2 runs before A: in this case, A sees elevated refcount and bails out |
| 130 | * - A runs before 2: in this case, 2 sees zero refcount and retries; |
| 131 | * subsequently, B will complete and 1 will find no page, causing the |
| 132 | * lookup to return NULL. |
| 133 | * |
| 134 | * It is possible that between 1 and 2, the page is removed then the exact same |
| 135 | * page is inserted into the same position in pagecache. That's OK: the |
| 136 | * old find_get_page using tree_lock could equally have run before or after |
| 137 | * such a re-insertion, depending on order that locks are granted. |
| 138 | * |
| 139 | * Lookups racing against pagecache insertion isn't a big problem: either 1 |
| 140 | * will find the page or it will not. Likewise, the old find_get_page could run |
| 141 | * either before the insertion or afterwards, depending on timing. |
| 142 | */ |
| 143 | static inline int page_cache_get_speculative(struct page *page) |
| 144 | { |
| 145 | VM_BUG_ON(in_interrupt()); |
| 146 | |
| 147 | #if !defined(CONFIG_SMP) && defined(CONFIG_CLASSIC_RCU) |
| 148 | # ifdef CONFIG_PREEMPT |
| 149 | VM_BUG_ON(!in_atomic()); |
| 150 | # endif |
| 151 | /* |
| 152 | * Preempt must be disabled here - we rely on rcu_read_lock doing |
| 153 | * this for us. |
| 154 | * |
| 155 | * Pagecache won't be truncated from interrupt context, so if we have |
| 156 | * found a page in the radix tree here, we have pinned its refcount by |
| 157 | * disabling preempt, and hence no need for the "speculative get" that |
| 158 | * SMP requires. |
| 159 | */ |
| 160 | VM_BUG_ON(page_count(page) == 0); |
| 161 | atomic_inc(&page->_count); |
| 162 | |
| 163 | #else |
| 164 | if (unlikely(!get_page_unless_zero(page))) { |
| 165 | /* |
| 166 | * Either the page has been freed, or will be freed. |
| 167 | * In either case, retry here and the caller should |
| 168 | * do the right thing (see comments above). |
| 169 | */ |
| 170 | return 0; |
| 171 | } |
| 172 | #endif |
| 173 | VM_BUG_ON(PageTail(page)); |
| 174 | |
| 175 | return 1; |
| 176 | } |
| 177 | |
Nick Piggin | ce0ad7f | 2008-07-30 15:23:13 +1000 | [diff] [blame] | 178 | /* |
| 179 | * Same as above, but add instead of inc (could just be merged) |
| 180 | */ |
| 181 | static inline int page_cache_add_speculative(struct page *page, int count) |
| 182 | { |
| 183 | VM_BUG_ON(in_interrupt()); |
| 184 | |
| 185 | #if !defined(CONFIG_SMP) && defined(CONFIG_CLASSIC_RCU) |
| 186 | # ifdef CONFIG_PREEMPT |
| 187 | VM_BUG_ON(!in_atomic()); |
| 188 | # endif |
| 189 | VM_BUG_ON(page_count(page) == 0); |
| 190 | atomic_add(count, &page->_count); |
| 191 | |
| 192 | #else |
| 193 | if (unlikely(!atomic_add_unless(&page->_count, count, 0))) |
| 194 | return 0; |
| 195 | #endif |
| 196 | VM_BUG_ON(PageCompound(page) && page != compound_head(page)); |
| 197 | |
| 198 | return 1; |
| 199 | } |
| 200 | |
Nick Piggin | e286781 | 2008-07-25 19:45:30 -0700 | [diff] [blame] | 201 | static inline int page_freeze_refs(struct page *page, int count) |
| 202 | { |
| 203 | return likely(atomic_cmpxchg(&page->_count, count, 0) == count); |
| 204 | } |
| 205 | |
| 206 | static inline void page_unfreeze_refs(struct page *page, int count) |
| 207 | { |
| 208 | VM_BUG_ON(page_count(page) != 0); |
| 209 | VM_BUG_ON(count == 0); |
| 210 | |
| 211 | atomic_set(&page->_count, count); |
| 212 | } |
| 213 | |
Paul Jackson | 44110fe | 2006-03-24 03:16:04 -0800 | [diff] [blame] | 214 | #ifdef CONFIG_NUMA |
Nick Piggin | 2ae8814 | 2006-10-28 10:38:23 -0700 | [diff] [blame] | 215 | extern struct page *__page_cache_alloc(gfp_t gfp); |
Paul Jackson | 44110fe | 2006-03-24 03:16:04 -0800 | [diff] [blame] | 216 | #else |
Nick Piggin | 2ae8814 | 2006-10-28 10:38:23 -0700 | [diff] [blame] | 217 | static inline struct page *__page_cache_alloc(gfp_t gfp) |
| 218 | { |
| 219 | return alloc_pages(gfp, 0); |
| 220 | } |
| 221 | #endif |
| 222 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 223 | static inline struct page *page_cache_alloc(struct address_space *x) |
| 224 | { |
Nick Piggin | 2ae8814 | 2006-10-28 10:38:23 -0700 | [diff] [blame] | 225 | return __page_cache_alloc(mapping_gfp_mask(x)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 226 | } |
| 227 | |
| 228 | static inline struct page *page_cache_alloc_cold(struct address_space *x) |
| 229 | { |
Nick Piggin | 2ae8814 | 2006-10-28 10:38:23 -0700 | [diff] [blame] | 230 | return __page_cache_alloc(mapping_gfp_mask(x)|__GFP_COLD); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 231 | } |
| 232 | |
| 233 | typedef int filler_t(void *, struct page *); |
| 234 | |
| 235 | extern struct page * find_get_page(struct address_space *mapping, |
Fengguang Wu | 57f6b96 | 2007-10-16 01:24:37 -0700 | [diff] [blame] | 236 | pgoff_t index); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 237 | extern struct page * find_lock_page(struct address_space *mapping, |
Fengguang Wu | 57f6b96 | 2007-10-16 01:24:37 -0700 | [diff] [blame] | 238 | pgoff_t index); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 239 | extern struct page * find_or_create_page(struct address_space *mapping, |
Fengguang Wu | 57f6b96 | 2007-10-16 01:24:37 -0700 | [diff] [blame] | 240 | pgoff_t index, gfp_t gfp_mask); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 241 | unsigned find_get_pages(struct address_space *mapping, pgoff_t start, |
| 242 | unsigned int nr_pages, struct page **pages); |
Jens Axboe | ebf4350 | 2006-04-27 08:46:01 +0200 | [diff] [blame] | 243 | unsigned find_get_pages_contig(struct address_space *mapping, pgoff_t start, |
| 244 | unsigned int nr_pages, struct page **pages); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 245 | unsigned find_get_pages_tag(struct address_space *mapping, pgoff_t *index, |
| 246 | int tag, unsigned int nr_pages, struct page **pages); |
| 247 | |
Nick Piggin | 54566b2 | 2009-01-04 12:00:53 -0800 | [diff] [blame] | 248 | struct page *grab_cache_page_write_begin(struct address_space *mapping, |
| 249 | pgoff_t index, unsigned flags); |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 250 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 251 | /* |
| 252 | * Returns locked page at given index in given cache, creating it if needed. |
| 253 | */ |
Fengguang Wu | 57f6b96 | 2007-10-16 01:24:37 -0700 | [diff] [blame] | 254 | static inline struct page *grab_cache_page(struct address_space *mapping, |
| 255 | pgoff_t index) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 256 | { |
| 257 | return find_or_create_page(mapping, index, mapping_gfp_mask(mapping)); |
| 258 | } |
| 259 | |
| 260 | extern struct page * grab_cache_page_nowait(struct address_space *mapping, |
Fengguang Wu | 57f6b96 | 2007-10-16 01:24:37 -0700 | [diff] [blame] | 261 | pgoff_t index); |
Nick Piggin | 6fe6900 | 2007-05-06 14:49:04 -0700 | [diff] [blame] | 262 | extern struct page * read_cache_page_async(struct address_space *mapping, |
Fengguang Wu | 57f6b96 | 2007-10-16 01:24:37 -0700 | [diff] [blame] | 263 | pgoff_t index, filler_t *filler, |
Nick Piggin | 6fe6900 | 2007-05-06 14:49:04 -0700 | [diff] [blame] | 264 | void *data); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 265 | extern struct page * read_cache_page(struct address_space *mapping, |
Fengguang Wu | 57f6b96 | 2007-10-16 01:24:37 -0700 | [diff] [blame] | 266 | pgoff_t index, filler_t *filler, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 267 | void *data); |
| 268 | extern int read_cache_pages(struct address_space *mapping, |
| 269 | struct list_head *pages, filler_t *filler, void *data); |
| 270 | |
Nick Piggin | 6fe6900 | 2007-05-06 14:49:04 -0700 | [diff] [blame] | 271 | static inline struct page *read_mapping_page_async( |
| 272 | struct address_space *mapping, |
Fengguang Wu | 57f6b96 | 2007-10-16 01:24:37 -0700 | [diff] [blame] | 273 | pgoff_t index, void *data) |
Nick Piggin | 6fe6900 | 2007-05-06 14:49:04 -0700 | [diff] [blame] | 274 | { |
| 275 | filler_t *filler = (filler_t *)mapping->a_ops->readpage; |
| 276 | return read_cache_page_async(mapping, index, filler, data); |
| 277 | } |
| 278 | |
Pekka Enberg | 090d2b1 | 2006-06-23 02:05:08 -0700 | [diff] [blame] | 279 | static inline struct page *read_mapping_page(struct address_space *mapping, |
Fengguang Wu | 57f6b96 | 2007-10-16 01:24:37 -0700 | [diff] [blame] | 280 | pgoff_t index, void *data) |
Pekka Enberg | 090d2b1 | 2006-06-23 02:05:08 -0700 | [diff] [blame] | 281 | { |
| 282 | filler_t *filler = (filler_t *)mapping->a_ops->readpage; |
| 283 | return read_cache_page(mapping, index, filler, data); |
| 284 | } |
| 285 | |
Nick Piggin | e286781 | 2008-07-25 19:45:30 -0700 | [diff] [blame] | 286 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 287 | * Return byte-offset into filesystem object for page. |
| 288 | */ |
| 289 | static inline loff_t page_offset(struct page *page) |
| 290 | { |
| 291 | return ((loff_t)page->index) << PAGE_CACHE_SHIFT; |
| 292 | } |
| 293 | |
| 294 | static inline pgoff_t linear_page_index(struct vm_area_struct *vma, |
| 295 | unsigned long address) |
| 296 | { |
| 297 | pgoff_t pgoff = (address - vma->vm_start) >> PAGE_SHIFT; |
| 298 | pgoff += vma->vm_pgoff; |
| 299 | return pgoff >> (PAGE_CACHE_SHIFT - PAGE_SHIFT); |
| 300 | } |
| 301 | |
Harvey Harrison | b3c9752 | 2008-02-13 15:03:15 -0800 | [diff] [blame] | 302 | extern void __lock_page(struct page *page); |
| 303 | extern int __lock_page_killable(struct page *page); |
| 304 | extern void __lock_page_nosync(struct page *page); |
| 305 | extern void unlock_page(struct page *page); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 306 | |
Nick Piggin | f45840b | 2008-10-18 20:26:57 -0700 | [diff] [blame] | 307 | static inline void __set_page_locked(struct page *page) |
Nick Piggin | 529ae9a | 2008-08-02 12:01:03 +0200 | [diff] [blame] | 308 | { |
Nick Piggin | f45840b | 2008-10-18 20:26:57 -0700 | [diff] [blame] | 309 | __set_bit(PG_locked, &page->flags); |
Nick Piggin | 529ae9a | 2008-08-02 12:01:03 +0200 | [diff] [blame] | 310 | } |
| 311 | |
Nick Piggin | f45840b | 2008-10-18 20:26:57 -0700 | [diff] [blame] | 312 | static inline void __clear_page_locked(struct page *page) |
Nick Piggin | 529ae9a | 2008-08-02 12:01:03 +0200 | [diff] [blame] | 313 | { |
Nick Piggin | f45840b | 2008-10-18 20:26:57 -0700 | [diff] [blame] | 314 | __clear_bit(PG_locked, &page->flags); |
Nick Piggin | 529ae9a | 2008-08-02 12:01:03 +0200 | [diff] [blame] | 315 | } |
| 316 | |
| 317 | static inline int trylock_page(struct page *page) |
| 318 | { |
Nick Piggin | 8413ac9 | 2008-10-18 20:26:59 -0700 | [diff] [blame] | 319 | return (likely(!test_and_set_bit_lock(PG_locked, &page->flags))); |
Nick Piggin | 529ae9a | 2008-08-02 12:01:03 +0200 | [diff] [blame] | 320 | } |
| 321 | |
Nick Piggin | db37648 | 2006-09-25 23:31:24 -0700 | [diff] [blame] | 322 | /* |
| 323 | * lock_page may only be called if we have the page's inode pinned. |
| 324 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 325 | static inline void lock_page(struct page *page) |
| 326 | { |
| 327 | might_sleep(); |
Nick Piggin | 529ae9a | 2008-08-02 12:01:03 +0200 | [diff] [blame] | 328 | if (!trylock_page(page)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 329 | __lock_page(page); |
| 330 | } |
Nick Piggin | db37648 | 2006-09-25 23:31:24 -0700 | [diff] [blame] | 331 | |
| 332 | /* |
Matthew Wilcox | 2687a35 | 2007-12-06 11:18:49 -0500 | [diff] [blame] | 333 | * lock_page_killable is like lock_page but can be interrupted by fatal |
| 334 | * signals. It returns 0 if it locked the page and -EINTR if it was |
| 335 | * killed while waiting. |
| 336 | */ |
| 337 | static inline int lock_page_killable(struct page *page) |
| 338 | { |
| 339 | might_sleep(); |
Nick Piggin | 529ae9a | 2008-08-02 12:01:03 +0200 | [diff] [blame] | 340 | if (!trylock_page(page)) |
Matthew Wilcox | 2687a35 | 2007-12-06 11:18:49 -0500 | [diff] [blame] | 341 | return __lock_page_killable(page); |
| 342 | return 0; |
| 343 | } |
| 344 | |
| 345 | /* |
Nick Piggin | db37648 | 2006-09-25 23:31:24 -0700 | [diff] [blame] | 346 | * lock_page_nosync should only be used if we can't pin the page's inode. |
| 347 | * Doesn't play quite so well with block device plugging. |
| 348 | */ |
| 349 | static inline void lock_page_nosync(struct page *page) |
| 350 | { |
| 351 | might_sleep(); |
Nick Piggin | 529ae9a | 2008-08-02 12:01:03 +0200 | [diff] [blame] | 352 | if (!trylock_page(page)) |
Nick Piggin | db37648 | 2006-09-25 23:31:24 -0700 | [diff] [blame] | 353 | __lock_page_nosync(page); |
| 354 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 355 | |
| 356 | /* |
| 357 | * This is exported only for wait_on_page_locked/wait_on_page_writeback. |
| 358 | * Never use this directly! |
| 359 | */ |
Harvey Harrison | b3c9752 | 2008-02-13 15:03:15 -0800 | [diff] [blame] | 360 | extern void wait_on_page_bit(struct page *page, int bit_nr); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 361 | |
| 362 | /* |
| 363 | * Wait for a page to be unlocked. |
| 364 | * |
| 365 | * This must be called with the caller "holding" the page, |
| 366 | * ie with increased "page->count" so that the page won't |
| 367 | * go away during the wait.. |
| 368 | */ |
| 369 | static inline void wait_on_page_locked(struct page *page) |
| 370 | { |
| 371 | if (PageLocked(page)) |
| 372 | wait_on_page_bit(page, PG_locked); |
| 373 | } |
| 374 | |
| 375 | /* |
| 376 | * Wait for a page to complete writeback |
| 377 | */ |
| 378 | static inline void wait_on_page_writeback(struct page *page) |
| 379 | { |
| 380 | if (PageWriteback(page)) |
| 381 | wait_on_page_bit(page, PG_writeback); |
| 382 | } |
| 383 | |
| 384 | extern void end_page_writeback(struct page *page); |
| 385 | |
| 386 | /* |
David Howells | 385e1ca5f | 2009-04-03 16:42:39 +0100 | [diff] [blame] | 387 | * Add an arbitrary waiter to a page's wait queue |
| 388 | */ |
| 389 | extern void add_page_wait_queue(struct page *page, wait_queue_t *waiter); |
| 390 | |
| 391 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 392 | * Fault a userspace page into pagetables. Return non-zero on a fault. |
| 393 | * |
| 394 | * This assumes that two userspace pages are always sufficient. That's |
| 395 | * not true if PAGE_CACHE_SIZE > PAGE_SIZE. |
| 396 | */ |
| 397 | static inline int fault_in_pages_writeable(char __user *uaddr, int size) |
| 398 | { |
| 399 | int ret; |
| 400 | |
Nick Piggin | 0829142 | 2007-10-16 01:24:59 -0700 | [diff] [blame] | 401 | if (unlikely(size == 0)) |
| 402 | return 0; |
| 403 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 404 | /* |
| 405 | * Writing zeroes into userspace here is OK, because we know that if |
| 406 | * the zero gets there, we'll be overwriting it. |
| 407 | */ |
| 408 | ret = __put_user(0, uaddr); |
| 409 | if (ret == 0) { |
| 410 | char __user *end = uaddr + size - 1; |
| 411 | |
| 412 | /* |
| 413 | * If the page was already mapped, this will get a cache miss |
| 414 | * for sure, so try to avoid doing it. |
| 415 | */ |
| 416 | if (((unsigned long)uaddr & PAGE_MASK) != |
| 417 | ((unsigned long)end & PAGE_MASK)) |
| 418 | ret = __put_user(0, end); |
| 419 | } |
| 420 | return ret; |
| 421 | } |
| 422 | |
Nick Piggin | 0829142 | 2007-10-16 01:24:59 -0700 | [diff] [blame] | 423 | static inline int fault_in_pages_readable(const char __user *uaddr, int size) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 424 | { |
| 425 | volatile char c; |
| 426 | int ret; |
| 427 | |
Nick Piggin | 0829142 | 2007-10-16 01:24:59 -0700 | [diff] [blame] | 428 | if (unlikely(size == 0)) |
| 429 | return 0; |
| 430 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 431 | ret = __get_user(c, uaddr); |
| 432 | if (ret == 0) { |
| 433 | const char __user *end = uaddr + size - 1; |
| 434 | |
| 435 | if (((unsigned long)uaddr & PAGE_MASK) != |
| 436 | ((unsigned long)end & PAGE_MASK)) |
Nick Piggin | 0829142 | 2007-10-16 01:24:59 -0700 | [diff] [blame] | 437 | ret = __get_user(c, end); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 438 | } |
Nick Piggin | 0829142 | 2007-10-16 01:24:59 -0700 | [diff] [blame] | 439 | return ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 440 | } |
| 441 | |
Nick Piggin | 529ae9a | 2008-08-02 12:01:03 +0200 | [diff] [blame] | 442 | int add_to_page_cache_locked(struct page *page, struct address_space *mapping, |
| 443 | pgoff_t index, gfp_t gfp_mask); |
| 444 | int add_to_page_cache_lru(struct page *page, struct address_space *mapping, |
| 445 | pgoff_t index, gfp_t gfp_mask); |
| 446 | extern void remove_from_page_cache(struct page *page); |
| 447 | extern void __remove_from_page_cache(struct page *page); |
| 448 | |
| 449 | /* |
| 450 | * Like add_to_page_cache_locked, but used to add newly allocated pages: |
Nick Piggin | f45840b | 2008-10-18 20:26:57 -0700 | [diff] [blame] | 451 | * the page is new, so we can just run __set_page_locked() against it. |
Nick Piggin | 529ae9a | 2008-08-02 12:01:03 +0200 | [diff] [blame] | 452 | */ |
| 453 | static inline int add_to_page_cache(struct page *page, |
| 454 | struct address_space *mapping, pgoff_t offset, gfp_t gfp_mask) |
| 455 | { |
| 456 | int error; |
| 457 | |
Nick Piggin | f45840b | 2008-10-18 20:26:57 -0700 | [diff] [blame] | 458 | __set_page_locked(page); |
Nick Piggin | 529ae9a | 2008-08-02 12:01:03 +0200 | [diff] [blame] | 459 | error = add_to_page_cache_locked(page, mapping, offset, gfp_mask); |
| 460 | if (unlikely(error)) |
Nick Piggin | f45840b | 2008-10-18 20:26:57 -0700 | [diff] [blame] | 461 | __clear_page_locked(page); |
Nick Piggin | 529ae9a | 2008-08-02 12:01:03 +0200 | [diff] [blame] | 462 | return error; |
| 463 | } |
| 464 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 465 | #endif /* _LINUX_PAGEMAP_H */ |