Nitin Gupta | 306b0c9 | 2009-09-22 10:26:53 +0530 | [diff] [blame] | 1 | /* |
| 2 | * Compressed RAM based swap device |
| 3 | * |
Nitin Gupta | 1130ebb | 2010-01-28 21:21:35 +0530 | [diff] [blame] | 4 | * Copyright (C) 2008, 2009, 2010 Nitin Gupta |
Nitin Gupta | 306b0c9 | 2009-09-22 10:26:53 +0530 | [diff] [blame] | 5 | * |
| 6 | * This code is released using a dual license strategy: BSD/GPL |
| 7 | * You can choose the licence that better fits your requirements. |
| 8 | * |
| 9 | * Released under the terms of 3-clause BSD License |
| 10 | * Released under the terms of GNU General Public License Version 2.0 |
| 11 | * |
| 12 | * Project home: http://compcache.googlecode.com |
| 13 | */ |
| 14 | |
| 15 | #define KMSG_COMPONENT "ramzswap" |
| 16 | #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt |
| 17 | |
| 18 | #include <linux/module.h> |
| 19 | #include <linux/kernel.h> |
| 20 | #include <linux/bitops.h> |
| 21 | #include <linux/blkdev.h> |
| 22 | #include <linux/buffer_head.h> |
| 23 | #include <linux/device.h> |
| 24 | #include <linux/genhd.h> |
| 25 | #include <linux/highmem.h> |
Tejun Heo | 5a0e3ad | 2010-03-24 17:04:11 +0900 | [diff] [blame^] | 26 | #include <linux/slab.h> |
Nitin Gupta | 306b0c9 | 2009-09-22 10:26:53 +0530 | [diff] [blame] | 27 | #include <linux/lzo.h> |
Nitin Gupta | 306b0c9 | 2009-09-22 10:26:53 +0530 | [diff] [blame] | 28 | #include <linux/string.h> |
| 29 | #include <linux/swap.h> |
| 30 | #include <linux/swapops.h> |
| 31 | #include <linux/vmalloc.h> |
Nitin Gupta | 306b0c9 | 2009-09-22 10:26:53 +0530 | [diff] [blame] | 32 | |
| 33 | #include "ramzswap_drv.h" |
| 34 | |
| 35 | /* Globals */ |
| 36 | static int ramzswap_major; |
| 37 | static struct ramzswap *devices; |
| 38 | |
| 39 | /* |
| 40 | * Pages that compress to larger than this size are |
| 41 | * forwarded to backing swap, if present or stored |
| 42 | * uncompressed in memory otherwise. |
| 43 | */ |
| 44 | static unsigned int max_zpage_size; |
| 45 | |
| 46 | /* Module params (documentation at end) */ |
| 47 | static unsigned int num_devices; |
| 48 | |
| 49 | static int rzs_test_flag(struct ramzswap *rzs, u32 index, |
| 50 | enum rzs_pageflags flag) |
| 51 | { |
| 52 | return rzs->table[index].flags & BIT(flag); |
| 53 | } |
| 54 | |
| 55 | static void rzs_set_flag(struct ramzswap *rzs, u32 index, |
| 56 | enum rzs_pageflags flag) |
| 57 | { |
| 58 | rzs->table[index].flags |= BIT(flag); |
| 59 | } |
| 60 | |
| 61 | static void rzs_clear_flag(struct ramzswap *rzs, u32 index, |
| 62 | enum rzs_pageflags flag) |
| 63 | { |
| 64 | rzs->table[index].flags &= ~BIT(flag); |
| 65 | } |
| 66 | |
| 67 | static int page_zero_filled(void *ptr) |
| 68 | { |
| 69 | unsigned int pos; |
| 70 | unsigned long *page; |
| 71 | |
| 72 | page = (unsigned long *)ptr; |
| 73 | |
| 74 | for (pos = 0; pos != PAGE_SIZE / sizeof(*page); pos++) { |
| 75 | if (page[pos]) |
| 76 | return 0; |
| 77 | } |
| 78 | |
| 79 | return 1; |
| 80 | } |
| 81 | |
| 82 | /* |
| 83 | * memlimit cannot be greater than backing disk size. |
| 84 | */ |
| 85 | static void ramzswap_set_memlimit(struct ramzswap *rzs, size_t totalram_bytes) |
| 86 | { |
| 87 | int memlimit_valid = 1; |
| 88 | |
| 89 | if (!rzs->memlimit) { |
| 90 | pr_info("Memory limit not set.\n"); |
| 91 | memlimit_valid = 0; |
| 92 | } |
| 93 | |
| 94 | if (rzs->memlimit > rzs->disksize) { |
| 95 | pr_info("Memory limit cannot be greater than " |
| 96 | "disksize: limit=%zu, disksize=%zu\n", |
| 97 | rzs->memlimit, rzs->disksize); |
| 98 | memlimit_valid = 0; |
| 99 | } |
| 100 | |
| 101 | if (!memlimit_valid) { |
| 102 | size_t mempart, disksize; |
| 103 | pr_info("Using default: smaller of (%u%% of RAM) and " |
| 104 | "(backing disk size).\n", |
| 105 | default_memlimit_perc_ram); |
| 106 | mempart = default_memlimit_perc_ram * (totalram_bytes / 100); |
| 107 | disksize = rzs->disksize; |
| 108 | rzs->memlimit = mempart > disksize ? disksize : mempart; |
| 109 | } |
| 110 | |
| 111 | if (rzs->memlimit > totalram_bytes / 2) { |
| 112 | pr_info( |
| 113 | "Its not advisable setting limit more than half of " |
| 114 | "size of memory since we expect a 2:1 compression ratio. " |
| 115 | "Limit represents amount of *compressed* data we can keep " |
| 116 | "in memory!\n" |
| 117 | "\tMemory Size: %zu kB\n" |
| 118 | "\tLimit you selected: %zu kB\n" |
| 119 | "Continuing anyway ...\n", |
| 120 | totalram_bytes >> 10, rzs->memlimit >> 10 |
| 121 | ); |
| 122 | } |
| 123 | |
| 124 | rzs->memlimit &= PAGE_MASK; |
| 125 | BUG_ON(!rzs->memlimit); |
| 126 | } |
| 127 | |
| 128 | static void ramzswap_set_disksize(struct ramzswap *rzs, size_t totalram_bytes) |
| 129 | { |
| 130 | if (!rzs->disksize) { |
| 131 | pr_info( |
| 132 | "disk size not provided. You can use disksize_kb module " |
| 133 | "param to specify size.\nUsing default: (%u%% of RAM).\n", |
| 134 | default_disksize_perc_ram |
| 135 | ); |
| 136 | rzs->disksize = default_disksize_perc_ram * |
| 137 | (totalram_bytes / 100); |
| 138 | } |
| 139 | |
| 140 | if (rzs->disksize > 2 * (totalram_bytes)) { |
| 141 | pr_info( |
| 142 | "There is little point creating a ramzswap of greater than " |
| 143 | "twice the size of memory since we expect a 2:1 compression " |
| 144 | "ratio. Note that ramzswap uses about 0.1%% of the size of " |
| 145 | "the swap device when not in use so a huge ramzswap is " |
| 146 | "wasteful.\n" |
| 147 | "\tMemory Size: %zu kB\n" |
| 148 | "\tSize you selected: %zu kB\n" |
| 149 | "Continuing anyway ...\n", |
| 150 | totalram_bytes >> 10, rzs->disksize |
| 151 | ); |
| 152 | } |
| 153 | |
| 154 | rzs->disksize &= PAGE_MASK; |
| 155 | } |
| 156 | |
| 157 | /* |
| 158 | * Swap header (1st page of swap device) contains information |
| 159 | * to indentify it as a swap partition. Prepare such a header |
| 160 | * for ramzswap device (ramzswap0) so that swapon can identify |
| 161 | * it as swap partition. In case backing swap device is provided, |
| 162 | * copy its swap header. |
| 163 | */ |
| 164 | static int setup_swap_header(struct ramzswap *rzs, union swap_header *s) |
| 165 | { |
| 166 | int ret = 0; |
| 167 | struct page *page; |
| 168 | struct address_space *mapping; |
| 169 | union swap_header *backing_swap_header; |
| 170 | |
| 171 | /* |
| 172 | * There is no backing swap device. Create a swap header |
| 173 | * that is acceptable by swapon. |
| 174 | */ |
| 175 | if (!rzs->backing_swap) { |
| 176 | s->info.version = 1; |
| 177 | s->info.last_page = (rzs->disksize >> PAGE_SHIFT) - 1; |
| 178 | s->info.nr_badpages = 0; |
| 179 | memcpy(s->magic.magic, "SWAPSPACE2", 10); |
| 180 | return 0; |
| 181 | } |
| 182 | |
| 183 | /* |
| 184 | * We have a backing swap device. Copy its swap header |
| 185 | * to ramzswap device header. If this header contains |
| 186 | * invalid information (backing device not a swap |
| 187 | * partition, etc.), swapon will fail for ramzswap |
| 188 | * which is correct behavior - we don't want to swap |
| 189 | * over filesystem partition! |
| 190 | */ |
| 191 | |
| 192 | /* Read the backing swap header (code from sys_swapon) */ |
| 193 | mapping = rzs->swap_file->f_mapping; |
| 194 | if (!mapping->a_ops->readpage) { |
| 195 | ret = -EINVAL; |
| 196 | goto out; |
| 197 | } |
| 198 | |
| 199 | page = read_mapping_page(mapping, 0, rzs->swap_file); |
| 200 | if (IS_ERR(page)) { |
| 201 | ret = PTR_ERR(page); |
| 202 | goto out; |
| 203 | } |
| 204 | |
| 205 | backing_swap_header = kmap(page); |
| 206 | memcpy(s, backing_swap_header, sizeof(*s)); |
| 207 | if (s->info.nr_badpages) { |
| 208 | pr_info("Cannot use backing swap with bad pages (%u)\n", |
| 209 | s->info.nr_badpages); |
| 210 | ret = -EINVAL; |
| 211 | } |
| 212 | /* |
| 213 | * ramzswap disksize equals number of usable pages in backing |
| 214 | * swap. Set last_page in swap header to match this disksize |
| 215 | * ('last_page' means 0-based index of last usable swap page). |
| 216 | */ |
| 217 | s->info.last_page = (rzs->disksize >> PAGE_SHIFT) - 1; |
| 218 | kunmap(page); |
| 219 | |
| 220 | out: |
| 221 | return ret; |
| 222 | } |
| 223 | |
Nitin Gupta | c25d75a | 2010-01-28 21:19:59 +0530 | [diff] [blame] | 224 | static void ramzswap_ioctl_get_stats(struct ramzswap *rzs, |
Nitin Gupta | 306b0c9 | 2009-09-22 10:26:53 +0530 | [diff] [blame] | 225 | struct ramzswap_ioctl_stats *s) |
| 226 | { |
| 227 | strncpy(s->backing_swap_name, rzs->backing_swap_name, |
| 228 | MAX_SWAP_NAME_LEN - 1); |
| 229 | s->backing_swap_name[MAX_SWAP_NAME_LEN - 1] = '\0'; |
| 230 | |
| 231 | s->disksize = rzs->disksize; |
| 232 | s->memlimit = rzs->memlimit; |
| 233 | |
| 234 | #if defined(CONFIG_RAMZSWAP_STATS) |
| 235 | { |
| 236 | struct ramzswap_stats *rs = &rzs->stats; |
| 237 | size_t succ_writes, mem_used; |
| 238 | unsigned int good_compress_perc = 0, no_compress_perc = 0; |
| 239 | |
| 240 | mem_used = xv_get_total_size_bytes(rzs->mem_pool) |
| 241 | + (rs->pages_expand << PAGE_SHIFT); |
Nitin Gupta | 6a90772 | 2010-01-28 21:13:37 +0530 | [diff] [blame] | 242 | succ_writes = rzs_stat64_read(rzs, &rs->num_writes) - |
| 243 | rzs_stat64_read(rzs, &rs->failed_writes); |
Nitin Gupta | 306b0c9 | 2009-09-22 10:26:53 +0530 | [diff] [blame] | 244 | |
| 245 | if (succ_writes && rs->pages_stored) { |
| 246 | good_compress_perc = rs->good_compress * 100 |
| 247 | / rs->pages_stored; |
| 248 | no_compress_perc = rs->pages_expand * 100 |
| 249 | / rs->pages_stored; |
| 250 | } |
| 251 | |
Nitin Gupta | 6a90772 | 2010-01-28 21:13:37 +0530 | [diff] [blame] | 252 | s->num_reads = rzs_stat64_read(rzs, &rs->num_reads); |
| 253 | s->num_writes = rzs_stat64_read(rzs, &rs->num_writes); |
| 254 | s->failed_reads = rzs_stat64_read(rzs, &rs->failed_reads); |
| 255 | s->failed_writes = rzs_stat64_read(rzs, &rs->failed_writes); |
| 256 | s->invalid_io = rzs_stat64_read(rzs, &rs->invalid_io); |
| 257 | s->notify_free = rzs_stat64_read(rzs, &rs->notify_free); |
Nitin Gupta | 306b0c9 | 2009-09-22 10:26:53 +0530 | [diff] [blame] | 258 | s->pages_zero = rs->pages_zero; |
| 259 | |
| 260 | s->good_compress_pct = good_compress_perc; |
| 261 | s->pages_expand_pct = no_compress_perc; |
| 262 | |
| 263 | s->pages_stored = rs->pages_stored; |
| 264 | s->pages_used = mem_used >> PAGE_SHIFT; |
| 265 | s->orig_data_size = rs->pages_stored << PAGE_SHIFT; |
| 266 | s->compr_data_size = rs->compr_size; |
| 267 | s->mem_used_total = mem_used; |
| 268 | |
Nitin Gupta | 6a90772 | 2010-01-28 21:13:37 +0530 | [diff] [blame] | 269 | s->bdev_num_reads = rzs_stat64_read(rzs, &rs->bdev_num_reads); |
| 270 | s->bdev_num_writes = rzs_stat64_read(rzs, &rs->bdev_num_writes); |
Nitin Gupta | 306b0c9 | 2009-09-22 10:26:53 +0530 | [diff] [blame] | 271 | } |
| 272 | #endif /* CONFIG_RAMZSWAP_STATS */ |
| 273 | } |
| 274 | |
| 275 | static int add_backing_swap_extent(struct ramzswap *rzs, |
| 276 | pgoff_t phy_pagenum, |
| 277 | pgoff_t num_pages) |
| 278 | { |
| 279 | unsigned int idx; |
| 280 | struct list_head *head; |
| 281 | struct page *curr_page, *new_page; |
| 282 | unsigned int extents_per_page = PAGE_SIZE / |
| 283 | sizeof(struct ramzswap_backing_extent); |
| 284 | |
| 285 | idx = rzs->num_extents % extents_per_page; |
| 286 | if (!idx) { |
| 287 | new_page = alloc_page(__GFP_ZERO); |
| 288 | if (!new_page) |
| 289 | return -ENOMEM; |
| 290 | |
| 291 | if (rzs->num_extents) { |
| 292 | curr_page = virt_to_page(rzs->curr_extent); |
| 293 | head = &curr_page->lru; |
| 294 | } else { |
| 295 | head = &rzs->backing_swap_extent_list; |
| 296 | } |
| 297 | |
| 298 | list_add(&new_page->lru, head); |
| 299 | rzs->curr_extent = page_address(new_page); |
| 300 | } |
| 301 | |
| 302 | rzs->curr_extent->phy_pagenum = phy_pagenum; |
| 303 | rzs->curr_extent->num_pages = num_pages; |
| 304 | |
| 305 | pr_debug("add_extent: idx=%u, phy_pgnum=%lu, num_pgs=%lu, " |
| 306 | "pg_last=%lu, curr_ext=%p\n", idx, phy_pagenum, num_pages, |
| 307 | phy_pagenum + num_pages - 1, rzs->curr_extent); |
| 308 | |
| 309 | if (idx != extents_per_page - 1) |
| 310 | rzs->curr_extent++; |
| 311 | |
| 312 | return 0; |
| 313 | } |
| 314 | |
| 315 | static int setup_backing_swap_extents(struct ramzswap *rzs, |
| 316 | struct inode *inode, unsigned long *num_pages) |
| 317 | { |
| 318 | int ret = 0; |
| 319 | unsigned blkbits; |
| 320 | unsigned blocks_per_page; |
| 321 | pgoff_t contig_pages = 0, total_pages = 0; |
| 322 | pgoff_t pagenum = 0, prev_pagenum = 0; |
| 323 | sector_t probe_block = 0; |
| 324 | sector_t last_block; |
| 325 | |
| 326 | blkbits = inode->i_blkbits; |
| 327 | blocks_per_page = PAGE_SIZE >> blkbits; |
| 328 | |
| 329 | last_block = i_size_read(inode) >> blkbits; |
| 330 | while (probe_block + blocks_per_page <= last_block) { |
| 331 | unsigned block_in_page; |
| 332 | sector_t first_block; |
| 333 | |
| 334 | first_block = bmap(inode, probe_block); |
| 335 | if (first_block == 0) |
| 336 | goto bad_bmap; |
| 337 | |
| 338 | /* It must be PAGE_SIZE aligned on-disk */ |
| 339 | if (first_block & (blocks_per_page - 1)) { |
| 340 | probe_block++; |
| 341 | goto probe_next; |
| 342 | } |
| 343 | |
| 344 | /* All blocks within this page must be contiguous on disk */ |
| 345 | for (block_in_page = 1; block_in_page < blocks_per_page; |
| 346 | block_in_page++) { |
| 347 | sector_t block; |
| 348 | |
| 349 | block = bmap(inode, probe_block + block_in_page); |
| 350 | if (block == 0) |
| 351 | goto bad_bmap; |
| 352 | if (block != first_block + block_in_page) { |
| 353 | /* Discontiguity */ |
| 354 | probe_block++; |
| 355 | goto probe_next; |
| 356 | } |
| 357 | } |
| 358 | |
| 359 | /* |
| 360 | * We found a PAGE_SIZE length, PAGE_SIZE aligned |
| 361 | * run of blocks. |
| 362 | */ |
| 363 | pagenum = first_block >> (PAGE_SHIFT - blkbits); |
| 364 | |
| 365 | if (total_pages && (pagenum != prev_pagenum + 1)) { |
| 366 | ret = add_backing_swap_extent(rzs, prev_pagenum - |
| 367 | (contig_pages - 1), contig_pages); |
| 368 | if (ret < 0) |
| 369 | goto out; |
| 370 | rzs->num_extents++; |
| 371 | contig_pages = 0; |
| 372 | } |
| 373 | total_pages++; |
| 374 | contig_pages++; |
| 375 | prev_pagenum = pagenum; |
| 376 | probe_block += blocks_per_page; |
| 377 | |
| 378 | probe_next: |
| 379 | continue; |
| 380 | } |
| 381 | |
| 382 | if (contig_pages) { |
| 383 | pr_debug("adding last extent: pagenum=%lu, " |
| 384 | "contig_pages=%lu\n", pagenum, contig_pages); |
| 385 | ret = add_backing_swap_extent(rzs, |
| 386 | prev_pagenum - (contig_pages - 1), contig_pages); |
| 387 | if (ret < 0) |
| 388 | goto out; |
| 389 | rzs->num_extents++; |
| 390 | } |
| 391 | if (!rzs->num_extents) { |
| 392 | pr_err("No swap extents found!\n"); |
| 393 | ret = -EINVAL; |
| 394 | } |
| 395 | |
| 396 | if (!ret) { |
| 397 | *num_pages = total_pages; |
| 398 | pr_info("Found %lu extents containing %luk\n", |
| 399 | rzs->num_extents, *num_pages << (PAGE_SHIFT - 10)); |
| 400 | } |
| 401 | goto out; |
| 402 | |
| 403 | bad_bmap: |
| 404 | pr_err("Backing swapfile has holes\n"); |
| 405 | ret = -EINVAL; |
| 406 | out: |
| 407 | while (ret && !list_empty(&rzs->backing_swap_extent_list)) { |
| 408 | struct page *page; |
| 409 | struct list_head *entry = rzs->backing_swap_extent_list.next; |
| 410 | page = list_entry(entry, struct page, lru); |
| 411 | list_del(entry); |
| 412 | __free_page(page); |
| 413 | } |
| 414 | return ret; |
| 415 | } |
| 416 | |
| 417 | static void map_backing_swap_extents(struct ramzswap *rzs) |
| 418 | { |
| 419 | struct ramzswap_backing_extent *se; |
| 420 | struct page *table_page, *se_page; |
| 421 | unsigned long num_pages, num_table_pages, entry; |
| 422 | unsigned long se_idx, span; |
| 423 | unsigned entries_per_page = PAGE_SIZE / sizeof(*rzs->table); |
| 424 | unsigned extents_per_page = PAGE_SIZE / sizeof(*se); |
| 425 | |
| 426 | /* True for block device */ |
| 427 | if (!rzs->num_extents) |
| 428 | return; |
| 429 | |
| 430 | se_page = list_entry(rzs->backing_swap_extent_list.next, |
| 431 | struct page, lru); |
| 432 | se = page_address(se_page); |
| 433 | span = se->num_pages; |
| 434 | num_pages = rzs->disksize >> PAGE_SHIFT; |
| 435 | num_table_pages = DIV_ROUND_UP(num_pages * sizeof(*rzs->table), |
| 436 | PAGE_SIZE); |
| 437 | |
| 438 | entry = 0; |
| 439 | se_idx = 0; |
| 440 | while (num_table_pages--) { |
| 441 | table_page = vmalloc_to_page(&rzs->table[entry]); |
| 442 | while (span <= entry) { |
| 443 | se_idx++; |
| 444 | if (se_idx == rzs->num_extents) |
| 445 | BUG(); |
| 446 | |
| 447 | if (!(se_idx % extents_per_page)) { |
| 448 | se_page = list_entry(se_page->lru.next, |
| 449 | struct page, lru); |
| 450 | se = page_address(se_page); |
| 451 | } else |
| 452 | se++; |
| 453 | |
| 454 | span += se->num_pages; |
| 455 | } |
| 456 | table_page->mapping = (struct address_space *)se; |
| 457 | table_page->private = se->num_pages - (span - entry); |
| 458 | pr_debug("map_table: entry=%lu, span=%lu, map=%p, priv=%lu\n", |
| 459 | entry, span, table_page->mapping, table_page->private); |
| 460 | entry += entries_per_page; |
| 461 | } |
| 462 | } |
| 463 | |
| 464 | /* |
| 465 | * Check if value of backing_swap module param is sane. |
| 466 | * Claim this device and set ramzswap size equal to |
| 467 | * size of this block device. |
| 468 | */ |
| 469 | static int setup_backing_swap(struct ramzswap *rzs) |
| 470 | { |
| 471 | int ret = 0; |
| 472 | size_t disksize; |
| 473 | unsigned long num_pages = 0; |
| 474 | struct inode *inode; |
| 475 | struct file *swap_file; |
| 476 | struct address_space *mapping; |
| 477 | struct block_device *bdev = NULL; |
| 478 | |
| 479 | if (!rzs->backing_swap_name[0]) { |
| 480 | pr_debug("backing_swap param not given\n"); |
| 481 | goto out; |
| 482 | } |
| 483 | |
| 484 | pr_info("Using backing swap device: %s\n", rzs->backing_swap_name); |
| 485 | |
| 486 | swap_file = filp_open(rzs->backing_swap_name, |
| 487 | O_RDWR | O_LARGEFILE, 0); |
| 488 | if (IS_ERR(swap_file)) { |
| 489 | pr_err("Error opening backing device: %s\n", |
| 490 | rzs->backing_swap_name); |
| 491 | ret = -EINVAL; |
| 492 | goto out; |
| 493 | } |
| 494 | |
| 495 | mapping = swap_file->f_mapping; |
| 496 | inode = mapping->host; |
| 497 | |
| 498 | if (S_ISBLK(inode->i_mode)) { |
| 499 | bdev = I_BDEV(inode); |
| 500 | ret = bd_claim(bdev, setup_backing_swap); |
| 501 | if (ret < 0) { |
| 502 | bdev = NULL; |
| 503 | goto bad_param; |
| 504 | } |
| 505 | disksize = i_size_read(inode); |
Nitin Gupta | c25d75a | 2010-01-28 21:19:59 +0530 | [diff] [blame] | 506 | /* |
| 507 | * Can happen if user gives an extended partition as |
| 508 | * backing swap or simply a bad disk. |
| 509 | */ |
| 510 | if (!disksize) { |
| 511 | pr_err("Error reading backing swap size.\n"); |
| 512 | goto bad_param; |
| 513 | } |
Nitin Gupta | 306b0c9 | 2009-09-22 10:26:53 +0530 | [diff] [blame] | 514 | } else if (S_ISREG(inode->i_mode)) { |
| 515 | bdev = inode->i_sb->s_bdev; |
| 516 | if (IS_SWAPFILE(inode)) { |
| 517 | ret = -EBUSY; |
| 518 | goto bad_param; |
| 519 | } |
| 520 | ret = setup_backing_swap_extents(rzs, inode, &num_pages); |
| 521 | if (ret < 0) |
| 522 | goto bad_param; |
| 523 | disksize = num_pages << PAGE_SHIFT; |
| 524 | } else { |
| 525 | goto bad_param; |
| 526 | } |
| 527 | |
| 528 | rzs->swap_file = swap_file; |
| 529 | rzs->backing_swap = bdev; |
| 530 | rzs->disksize = disksize; |
Nitin Gupta | 306b0c9 | 2009-09-22 10:26:53 +0530 | [diff] [blame] | 531 | |
| 532 | return 0; |
| 533 | |
| 534 | bad_param: |
| 535 | if (bdev) |
| 536 | bd_release(bdev); |
| 537 | filp_close(swap_file, NULL); |
| 538 | |
| 539 | out: |
| 540 | rzs->backing_swap = NULL; |
| 541 | return ret; |
| 542 | } |
| 543 | |
| 544 | /* |
| 545 | * Map logical page number 'pagenum' to physical page number |
| 546 | * on backing swap device. For block device, this is a nop. |
| 547 | */ |
Nitin Gupta | c25d75a | 2010-01-28 21:19:59 +0530 | [diff] [blame] | 548 | static u32 map_backing_swap_page(struct ramzswap *rzs, u32 pagenum) |
Nitin Gupta | 306b0c9 | 2009-09-22 10:26:53 +0530 | [diff] [blame] | 549 | { |
| 550 | u32 skip_pages, entries_per_page; |
| 551 | size_t delta, se_offset, skipped; |
| 552 | struct page *table_page, *se_page; |
| 553 | struct ramzswap_backing_extent *se; |
| 554 | |
| 555 | if (!rzs->num_extents) |
| 556 | return pagenum; |
| 557 | |
| 558 | entries_per_page = PAGE_SIZE / sizeof(*rzs->table); |
| 559 | |
| 560 | table_page = vmalloc_to_page(&rzs->table[pagenum]); |
| 561 | se = (struct ramzswap_backing_extent *)table_page->mapping; |
| 562 | se_page = virt_to_page(se); |
| 563 | |
| 564 | skip_pages = pagenum - (pagenum / entries_per_page * entries_per_page); |
| 565 | se_offset = table_page->private + skip_pages; |
| 566 | |
| 567 | if (se_offset < se->num_pages) |
| 568 | return se->phy_pagenum + se_offset; |
| 569 | |
| 570 | skipped = se->num_pages - table_page->private; |
| 571 | do { |
| 572 | struct ramzswap_backing_extent *se_base; |
| 573 | u32 se_entries_per_page = PAGE_SIZE / sizeof(*se); |
| 574 | |
| 575 | /* Get next swap extent */ |
| 576 | se_base = (struct ramzswap_backing_extent *) |
| 577 | page_address(se_page); |
| 578 | if (se - se_base == se_entries_per_page - 1) { |
| 579 | se_page = list_entry(se_page->lru.next, |
| 580 | struct page, lru); |
| 581 | se = page_address(se_page); |
| 582 | } else { |
| 583 | se++; |
| 584 | } |
| 585 | |
| 586 | skipped += se->num_pages; |
| 587 | } while (skipped < skip_pages); |
| 588 | |
| 589 | delta = skipped - skip_pages; |
| 590 | se_offset = se->num_pages - delta; |
| 591 | |
| 592 | return se->phy_pagenum + se_offset; |
| 593 | } |
| 594 | |
| 595 | static void ramzswap_free_page(struct ramzswap *rzs, size_t index) |
| 596 | { |
| 597 | u32 clen; |
| 598 | void *obj; |
| 599 | |
| 600 | struct page *page = rzs->table[index].page; |
| 601 | u32 offset = rzs->table[index].offset; |
| 602 | |
| 603 | if (unlikely(!page)) { |
Nitin Gupta | 2e88228 | 2010-01-28 21:13:41 +0530 | [diff] [blame] | 604 | /* |
| 605 | * No memory is allocated for zero filled pages. |
| 606 | * Simply clear zero page flag. |
| 607 | */ |
Nitin Gupta | 306b0c9 | 2009-09-22 10:26:53 +0530 | [diff] [blame] | 608 | if (rzs_test_flag(rzs, index, RZS_ZERO)) { |
| 609 | rzs_clear_flag(rzs, index, RZS_ZERO); |
Nitin Gupta | 6a90772 | 2010-01-28 21:13:37 +0530 | [diff] [blame] | 610 | rzs_stat_dec(&rzs->stats.pages_zero); |
Nitin Gupta | 306b0c9 | 2009-09-22 10:26:53 +0530 | [diff] [blame] | 611 | } |
| 612 | return; |
| 613 | } |
| 614 | |
| 615 | if (unlikely(rzs_test_flag(rzs, index, RZS_UNCOMPRESSED))) { |
| 616 | clen = PAGE_SIZE; |
| 617 | __free_page(page); |
| 618 | rzs_clear_flag(rzs, index, RZS_UNCOMPRESSED); |
Nitin Gupta | 6a90772 | 2010-01-28 21:13:37 +0530 | [diff] [blame] | 619 | rzs_stat_dec(&rzs->stats.pages_expand); |
Nitin Gupta | 306b0c9 | 2009-09-22 10:26:53 +0530 | [diff] [blame] | 620 | goto out; |
| 621 | } |
| 622 | |
| 623 | obj = kmap_atomic(page, KM_USER0) + offset; |
| 624 | clen = xv_get_object_size(obj) - sizeof(struct zobj_header); |
| 625 | kunmap_atomic(obj, KM_USER0); |
| 626 | |
| 627 | xv_free(rzs->mem_pool, page, offset); |
| 628 | if (clen <= PAGE_SIZE / 2) |
Nitin Gupta | 6a90772 | 2010-01-28 21:13:37 +0530 | [diff] [blame] | 629 | rzs_stat_dec(&rzs->stats.good_compress); |
Nitin Gupta | 306b0c9 | 2009-09-22 10:26:53 +0530 | [diff] [blame] | 630 | |
| 631 | out: |
| 632 | rzs->stats.compr_size -= clen; |
Nitin Gupta | 6a90772 | 2010-01-28 21:13:37 +0530 | [diff] [blame] | 633 | rzs_stat_dec(&rzs->stats.pages_stored); |
Nitin Gupta | 306b0c9 | 2009-09-22 10:26:53 +0530 | [diff] [blame] | 634 | |
| 635 | rzs->table[index].page = NULL; |
| 636 | rzs->table[index].offset = 0; |
| 637 | } |
| 638 | |
| 639 | static int handle_zero_page(struct bio *bio) |
| 640 | { |
| 641 | void *user_mem; |
| 642 | struct page *page = bio->bi_io_vec[0].bv_page; |
| 643 | |
| 644 | user_mem = kmap_atomic(page, KM_USER0); |
| 645 | memset(user_mem, 0, PAGE_SIZE); |
| 646 | kunmap_atomic(user_mem, KM_USER0); |
| 647 | |
Nitin Gupta | 30fb8a7 | 2009-12-12 11:44:46 +0530 | [diff] [blame] | 648 | flush_dcache_page(page); |
Nitin Gupta | 306b0c9 | 2009-09-22 10:26:53 +0530 | [diff] [blame] | 649 | |
| 650 | set_bit(BIO_UPTODATE, &bio->bi_flags); |
| 651 | bio_endio(bio, 0); |
| 652 | return 0; |
| 653 | } |
| 654 | |
| 655 | static int handle_uncompressed_page(struct ramzswap *rzs, struct bio *bio) |
| 656 | { |
| 657 | u32 index; |
| 658 | struct page *page; |
| 659 | unsigned char *user_mem, *cmem; |
| 660 | |
| 661 | page = bio->bi_io_vec[0].bv_page; |
| 662 | index = bio->bi_sector >> SECTORS_PER_PAGE_SHIFT; |
| 663 | |
| 664 | user_mem = kmap_atomic(page, KM_USER0); |
| 665 | cmem = kmap_atomic(rzs->table[index].page, KM_USER1) + |
| 666 | rzs->table[index].offset; |
| 667 | |
| 668 | memcpy(user_mem, cmem, PAGE_SIZE); |
| 669 | kunmap_atomic(user_mem, KM_USER0); |
| 670 | kunmap_atomic(cmem, KM_USER1); |
| 671 | |
Nitin Gupta | 30fb8a7 | 2009-12-12 11:44:46 +0530 | [diff] [blame] | 672 | flush_dcache_page(page); |
Nitin Gupta | 306b0c9 | 2009-09-22 10:26:53 +0530 | [diff] [blame] | 673 | |
| 674 | set_bit(BIO_UPTODATE, &bio->bi_flags); |
| 675 | bio_endio(bio, 0); |
| 676 | return 0; |
| 677 | } |
| 678 | |
Nitin Gupta | 306b0c9 | 2009-09-22 10:26:53 +0530 | [diff] [blame] | 679 | /* |
| 680 | * Called when request page is not present in ramzswap. |
| 681 | * Its either in backing swap device (if present) or |
| 682 | * this is an attempt to read before any previous write |
| 683 | * to this location - this happens due to readahead when |
| 684 | * swap device is read from user-space (e.g. during swapon) |
| 685 | */ |
| 686 | static int handle_ramzswap_fault(struct ramzswap *rzs, struct bio *bio) |
| 687 | { |
| 688 | /* |
| 689 | * Always forward such requests to backing swap |
| 690 | * device (if present) |
| 691 | */ |
| 692 | if (rzs->backing_swap) { |
| 693 | u32 pagenum; |
Nitin Gupta | 6a90772 | 2010-01-28 21:13:37 +0530 | [diff] [blame] | 694 | rzs_stat64_dec(rzs, &rzs->stats.num_reads); |
| 695 | rzs_stat64_inc(rzs, &rzs->stats.bdev_num_reads); |
Nitin Gupta | 306b0c9 | 2009-09-22 10:26:53 +0530 | [diff] [blame] | 696 | bio->bi_bdev = rzs->backing_swap; |
| 697 | |
| 698 | /* |
| 699 | * In case backing swap is a file, find the right offset within |
| 700 | * the file corresponding to logical position 'index'. For block |
| 701 | * device, this is a nop. |
| 702 | */ |
| 703 | pagenum = bio->bi_sector >> SECTORS_PER_PAGE_SHIFT; |
| 704 | bio->bi_sector = map_backing_swap_page(rzs, pagenum) |
| 705 | << SECTORS_PER_PAGE_SHIFT; |
| 706 | return 1; |
| 707 | } |
| 708 | |
| 709 | /* |
| 710 | * Its unlikely event in case backing dev is |
| 711 | * not present |
| 712 | */ |
| 713 | pr_debug("Read before write on swap device: " |
| 714 | "sector=%lu, size=%u, offset=%u\n", |
| 715 | (ulong)(bio->bi_sector), bio->bi_size, |
| 716 | bio->bi_io_vec[0].bv_offset); |
| 717 | |
| 718 | /* Do nothing. Just return success */ |
| 719 | set_bit(BIO_UPTODATE, &bio->bi_flags); |
| 720 | bio_endio(bio, 0); |
| 721 | return 0; |
| 722 | } |
| 723 | |
| 724 | static int ramzswap_read(struct ramzswap *rzs, struct bio *bio) |
| 725 | { |
| 726 | int ret; |
| 727 | u32 index; |
| 728 | size_t clen; |
| 729 | struct page *page; |
| 730 | struct zobj_header *zheader; |
| 731 | unsigned char *user_mem, *cmem; |
| 732 | |
Nitin Gupta | 6a90772 | 2010-01-28 21:13:37 +0530 | [diff] [blame] | 733 | rzs_stat64_inc(rzs, &rzs->stats.num_reads); |
Nitin Gupta | 306b0c9 | 2009-09-22 10:26:53 +0530 | [diff] [blame] | 734 | |
| 735 | page = bio->bi_io_vec[0].bv_page; |
| 736 | index = bio->bi_sector >> SECTORS_PER_PAGE_SHIFT; |
| 737 | |
| 738 | if (rzs_test_flag(rzs, index, RZS_ZERO)) |
| 739 | return handle_zero_page(bio); |
| 740 | |
| 741 | /* Requested page is not present in compressed area */ |
| 742 | if (!rzs->table[index].page) |
| 743 | return handle_ramzswap_fault(rzs, bio); |
| 744 | |
C yp | ef4ffb7 | 2010-01-06 13:42:00 +0100 | [diff] [blame] | 745 | /* Page is stored uncompressed since it's incompressible */ |
Nitin Gupta | 306b0c9 | 2009-09-22 10:26:53 +0530 | [diff] [blame] | 746 | if (unlikely(rzs_test_flag(rzs, index, RZS_UNCOMPRESSED))) |
| 747 | return handle_uncompressed_page(rzs, bio); |
| 748 | |
| 749 | user_mem = kmap_atomic(page, KM_USER0); |
| 750 | clen = PAGE_SIZE; |
| 751 | |
| 752 | cmem = kmap_atomic(rzs->table[index].page, KM_USER1) + |
| 753 | rzs->table[index].offset; |
| 754 | |
| 755 | ret = lzo1x_decompress_safe( |
| 756 | cmem + sizeof(*zheader), |
| 757 | xv_get_object_size(cmem) - sizeof(*zheader), |
| 758 | user_mem, &clen); |
| 759 | |
| 760 | kunmap_atomic(user_mem, KM_USER0); |
| 761 | kunmap_atomic(cmem, KM_USER1); |
| 762 | |
| 763 | /* should NEVER happen */ |
| 764 | if (unlikely(ret != LZO_E_OK)) { |
| 765 | pr_err("Decompression failed! err=%d, page=%u\n", |
| 766 | ret, index); |
Nitin Gupta | 6a90772 | 2010-01-28 21:13:37 +0530 | [diff] [blame] | 767 | rzs_stat64_inc(rzs, &rzs->stats.failed_reads); |
Nitin Gupta | 306b0c9 | 2009-09-22 10:26:53 +0530 | [diff] [blame] | 768 | goto out; |
| 769 | } |
| 770 | |
Nitin Gupta | 30fb8a7 | 2009-12-12 11:44:46 +0530 | [diff] [blame] | 771 | flush_dcache_page(page); |
Nitin Gupta | 306b0c9 | 2009-09-22 10:26:53 +0530 | [diff] [blame] | 772 | |
| 773 | set_bit(BIO_UPTODATE, &bio->bi_flags); |
| 774 | bio_endio(bio, 0); |
| 775 | return 0; |
| 776 | |
| 777 | out: |
| 778 | bio_io_error(bio); |
| 779 | return 0; |
| 780 | } |
| 781 | |
| 782 | static int ramzswap_write(struct ramzswap *rzs, struct bio *bio) |
| 783 | { |
| 784 | int ret, fwd_write_request = 0; |
| 785 | u32 offset, index; |
| 786 | size_t clen; |
| 787 | struct zobj_header *zheader; |
| 788 | struct page *page, *page_store; |
| 789 | unsigned char *user_mem, *cmem, *src; |
| 790 | |
Nitin Gupta | 6a90772 | 2010-01-28 21:13:37 +0530 | [diff] [blame] | 791 | rzs_stat64_inc(rzs, &rzs->stats.num_writes); |
Nitin Gupta | 306b0c9 | 2009-09-22 10:26:53 +0530 | [diff] [blame] | 792 | |
| 793 | page = bio->bi_io_vec[0].bv_page; |
| 794 | index = bio->bi_sector >> SECTORS_PER_PAGE_SHIFT; |
| 795 | |
| 796 | src = rzs->compress_buffer; |
| 797 | |
| 798 | /* |
| 799 | * System swaps to same sector again when the stored page |
| 800 | * is no longer referenced by any process. So, its now safe |
| 801 | * to free the memory that was allocated for this page. |
| 802 | */ |
Nitin Gupta | 2e88228 | 2010-01-28 21:13:41 +0530 | [diff] [blame] | 803 | if (rzs->table[index].page || rzs_test_flag(rzs, index, RZS_ZERO)) |
Nitin Gupta | 306b0c9 | 2009-09-22 10:26:53 +0530 | [diff] [blame] | 804 | ramzswap_free_page(rzs, index); |
| 805 | |
Nitin Gupta | 306b0c9 | 2009-09-22 10:26:53 +0530 | [diff] [blame] | 806 | mutex_lock(&rzs->lock); |
| 807 | |
| 808 | user_mem = kmap_atomic(page, KM_USER0); |
| 809 | if (page_zero_filled(user_mem)) { |
| 810 | kunmap_atomic(user_mem, KM_USER0); |
| 811 | mutex_unlock(&rzs->lock); |
Nitin Gupta | 6a90772 | 2010-01-28 21:13:37 +0530 | [diff] [blame] | 812 | rzs_stat_inc(&rzs->stats.pages_zero); |
Nitin Gupta | 306b0c9 | 2009-09-22 10:26:53 +0530 | [diff] [blame] | 813 | rzs_set_flag(rzs, index, RZS_ZERO); |
| 814 | |
| 815 | set_bit(BIO_UPTODATE, &bio->bi_flags); |
| 816 | bio_endio(bio, 0); |
| 817 | return 0; |
| 818 | } |
| 819 | |
| 820 | if (rzs->backing_swap && |
| 821 | (rzs->stats.compr_size > rzs->memlimit - PAGE_SIZE)) { |
| 822 | kunmap_atomic(user_mem, KM_USER0); |
| 823 | mutex_unlock(&rzs->lock); |
| 824 | fwd_write_request = 1; |
| 825 | goto out; |
| 826 | } |
| 827 | |
| 828 | ret = lzo1x_1_compress(user_mem, PAGE_SIZE, src, &clen, |
| 829 | rzs->compress_workmem); |
| 830 | |
| 831 | kunmap_atomic(user_mem, KM_USER0); |
| 832 | |
| 833 | if (unlikely(ret != LZO_E_OK)) { |
| 834 | mutex_unlock(&rzs->lock); |
| 835 | pr_err("Compression failed! err=%d\n", ret); |
Nitin Gupta | 6a90772 | 2010-01-28 21:13:37 +0530 | [diff] [blame] | 836 | rzs_stat64_inc(rzs, &rzs->stats.failed_writes); |
Nitin Gupta | 306b0c9 | 2009-09-22 10:26:53 +0530 | [diff] [blame] | 837 | goto out; |
| 838 | } |
| 839 | |
| 840 | /* |
| 841 | * Page is incompressible. Forward it to backing swap |
| 842 | * if present. Otherwise, store it as-is (uncompressed) |
| 843 | * since we do not want to return too many swap write |
| 844 | * errors which has side effect of hanging the system. |
| 845 | */ |
| 846 | if (unlikely(clen > max_zpage_size)) { |
| 847 | if (rzs->backing_swap) { |
| 848 | mutex_unlock(&rzs->lock); |
| 849 | fwd_write_request = 1; |
| 850 | goto out; |
| 851 | } |
| 852 | |
| 853 | clen = PAGE_SIZE; |
| 854 | page_store = alloc_page(GFP_NOIO | __GFP_HIGHMEM); |
| 855 | if (unlikely(!page_store)) { |
| 856 | mutex_unlock(&rzs->lock); |
| 857 | pr_info("Error allocating memory for incompressible " |
| 858 | "page: %u\n", index); |
Nitin Gupta | 6a90772 | 2010-01-28 21:13:37 +0530 | [diff] [blame] | 859 | rzs_stat64_inc(rzs, &rzs->stats.failed_writes); |
Nitin Gupta | 306b0c9 | 2009-09-22 10:26:53 +0530 | [diff] [blame] | 860 | goto out; |
| 861 | } |
| 862 | |
| 863 | offset = 0; |
| 864 | rzs_set_flag(rzs, index, RZS_UNCOMPRESSED); |
Nitin Gupta | 6a90772 | 2010-01-28 21:13:37 +0530 | [diff] [blame] | 865 | rzs_stat_inc(&rzs->stats.pages_expand); |
Nitin Gupta | 306b0c9 | 2009-09-22 10:26:53 +0530 | [diff] [blame] | 866 | rzs->table[index].page = page_store; |
| 867 | src = kmap_atomic(page, KM_USER0); |
| 868 | goto memstore; |
| 869 | } |
| 870 | |
| 871 | if (xv_malloc(rzs->mem_pool, clen + sizeof(*zheader), |
| 872 | &rzs->table[index].page, &offset, |
| 873 | GFP_NOIO | __GFP_HIGHMEM)) { |
| 874 | mutex_unlock(&rzs->lock); |
| 875 | pr_info("Error allocating memory for compressed " |
| 876 | "page: %u, size=%zu\n", index, clen); |
Nitin Gupta | 6a90772 | 2010-01-28 21:13:37 +0530 | [diff] [blame] | 877 | rzs_stat64_inc(rzs, &rzs->stats.failed_writes); |
Nitin Gupta | 306b0c9 | 2009-09-22 10:26:53 +0530 | [diff] [blame] | 878 | if (rzs->backing_swap) |
| 879 | fwd_write_request = 1; |
| 880 | goto out; |
| 881 | } |
| 882 | |
| 883 | memstore: |
| 884 | rzs->table[index].offset = offset; |
| 885 | |
| 886 | cmem = kmap_atomic(rzs->table[index].page, KM_USER1) + |
| 887 | rzs->table[index].offset; |
| 888 | |
| 889 | #if 0 |
| 890 | /* Back-reference needed for memory defragmentation */ |
| 891 | if (!rzs_test_flag(rzs, index, RZS_UNCOMPRESSED)) { |
| 892 | zheader = (struct zobj_header *)cmem; |
| 893 | zheader->table_idx = index; |
| 894 | cmem += sizeof(*zheader); |
| 895 | } |
| 896 | #endif |
| 897 | |
| 898 | memcpy(cmem, src, clen); |
| 899 | |
| 900 | kunmap_atomic(cmem, KM_USER1); |
| 901 | if (unlikely(rzs_test_flag(rzs, index, RZS_UNCOMPRESSED))) |
| 902 | kunmap_atomic(src, KM_USER0); |
| 903 | |
| 904 | /* Update stats */ |
| 905 | rzs->stats.compr_size += clen; |
Nitin Gupta | 6a90772 | 2010-01-28 21:13:37 +0530 | [diff] [blame] | 906 | rzs_stat_inc(&rzs->stats.pages_stored); |
Nitin Gupta | 306b0c9 | 2009-09-22 10:26:53 +0530 | [diff] [blame] | 907 | if (clen <= PAGE_SIZE / 2) |
Nitin Gupta | 6a90772 | 2010-01-28 21:13:37 +0530 | [diff] [blame] | 908 | rzs_stat_inc(&rzs->stats.good_compress); |
Nitin Gupta | 306b0c9 | 2009-09-22 10:26:53 +0530 | [diff] [blame] | 909 | |
| 910 | mutex_unlock(&rzs->lock); |
| 911 | |
| 912 | set_bit(BIO_UPTODATE, &bio->bi_flags); |
| 913 | bio_endio(bio, 0); |
| 914 | return 0; |
| 915 | |
| 916 | out: |
| 917 | if (fwd_write_request) { |
Nitin Gupta | 6a90772 | 2010-01-28 21:13:37 +0530 | [diff] [blame] | 918 | rzs_stat64_inc(rzs, &rzs->stats.bdev_num_writes); |
Nitin Gupta | 306b0c9 | 2009-09-22 10:26:53 +0530 | [diff] [blame] | 919 | bio->bi_bdev = rzs->backing_swap; |
| 920 | #if 0 |
| 921 | /* |
| 922 | * TODO: We currently have linear mapping of ramzswap and |
| 923 | * backing swap sectors. This is not desired since we want |
| 924 | * to optimize writes to backing swap to minimize disk seeks |
| 925 | * or have effective wear leveling (for SSDs). Also, a |
| 926 | * non-linear mapping is required to implement compressed |
| 927 | * on-disk swapping. |
| 928 | */ |
| 929 | bio->bi_sector = get_backing_swap_page() |
| 930 | << SECTORS_PER_PAGE_SHIFT; |
| 931 | #endif |
| 932 | /* |
| 933 | * In case backing swap is a file, find the right offset within |
| 934 | * the file corresponding to logical position 'index'. For block |
| 935 | * device, this is a nop. |
| 936 | */ |
| 937 | bio->bi_sector = map_backing_swap_page(rzs, index) |
| 938 | << SECTORS_PER_PAGE_SHIFT; |
| 939 | return 1; |
| 940 | } |
| 941 | |
| 942 | bio_io_error(bio); |
| 943 | return 0; |
| 944 | } |
| 945 | |
Nitin Gupta | 306b0c9 | 2009-09-22 10:26:53 +0530 | [diff] [blame] | 946 | /* |
| 947 | * Check if request is within bounds and page aligned. |
| 948 | */ |
| 949 | static inline int valid_swap_request(struct ramzswap *rzs, struct bio *bio) |
| 950 | { |
| 951 | if (unlikely( |
| 952 | (bio->bi_sector >= (rzs->disksize >> SECTOR_SHIFT)) || |
| 953 | (bio->bi_sector & (SECTORS_PER_PAGE - 1)) || |
| 954 | (bio->bi_vcnt != 1) || |
| 955 | (bio->bi_size != PAGE_SIZE) || |
| 956 | (bio->bi_io_vec[0].bv_offset != 0))) { |
| 957 | |
| 958 | return 0; |
| 959 | } |
| 960 | |
| 961 | /* swap request is valid */ |
| 962 | return 1; |
| 963 | } |
| 964 | |
| 965 | /* |
| 966 | * Handler function for all ramzswap I/O requests. |
| 967 | */ |
| 968 | static int ramzswap_make_request(struct request_queue *queue, struct bio *bio) |
| 969 | { |
| 970 | int ret = 0; |
| 971 | struct ramzswap *rzs = queue->queuedata; |
| 972 | |
| 973 | if (unlikely(!rzs->init_done)) { |
| 974 | bio_io_error(bio); |
| 975 | return 0; |
| 976 | } |
| 977 | |
| 978 | if (!valid_swap_request(rzs, bio)) { |
Nitin Gupta | 6a90772 | 2010-01-28 21:13:37 +0530 | [diff] [blame] | 979 | rzs_stat64_inc(rzs, &rzs->stats.invalid_io); |
Nitin Gupta | 306b0c9 | 2009-09-22 10:26:53 +0530 | [diff] [blame] | 980 | bio_io_error(bio); |
| 981 | return 0; |
| 982 | } |
| 983 | |
| 984 | switch (bio_data_dir(bio)) { |
| 985 | case READ: |
| 986 | ret = ramzswap_read(rzs, bio); |
| 987 | break; |
| 988 | |
| 989 | case WRITE: |
| 990 | ret = ramzswap_write(rzs, bio); |
| 991 | break; |
| 992 | } |
| 993 | |
| 994 | return ret; |
| 995 | } |
| 996 | |
| 997 | static void reset_device(struct ramzswap *rzs) |
| 998 | { |
| 999 | int is_backing_blkdev = 0; |
| 1000 | size_t index, num_pages; |
| 1001 | unsigned entries_per_page; |
| 1002 | unsigned long num_table_pages, entry = 0; |
| 1003 | |
Nitin Gupta | 7eef753 | 2010-01-28 21:13:38 +0530 | [diff] [blame] | 1004 | /* Do not accept any new I/O request */ |
| 1005 | rzs->init_done = 0; |
| 1006 | |
Nitin Gupta | 306b0c9 | 2009-09-22 10:26:53 +0530 | [diff] [blame] | 1007 | if (rzs->backing_swap && !rzs->num_extents) |
| 1008 | is_backing_blkdev = 1; |
| 1009 | |
| 1010 | num_pages = rzs->disksize >> PAGE_SHIFT; |
| 1011 | |
| 1012 | /* Free various per-device buffers */ |
| 1013 | kfree(rzs->compress_workmem); |
| 1014 | free_pages((unsigned long)rzs->compress_buffer, 1); |
| 1015 | |
| 1016 | rzs->compress_workmem = NULL; |
| 1017 | rzs->compress_buffer = NULL; |
| 1018 | |
| 1019 | /* Free all pages that are still in this ramzswap device */ |
| 1020 | for (index = 0; index < num_pages; index++) { |
| 1021 | struct page *page; |
| 1022 | u16 offset; |
| 1023 | |
| 1024 | page = rzs->table[index].page; |
| 1025 | offset = rzs->table[index].offset; |
| 1026 | |
| 1027 | if (!page) |
| 1028 | continue; |
| 1029 | |
| 1030 | if (unlikely(rzs_test_flag(rzs, index, RZS_UNCOMPRESSED))) |
| 1031 | __free_page(page); |
| 1032 | else |
| 1033 | xv_free(rzs->mem_pool, page, offset); |
| 1034 | } |
| 1035 | |
| 1036 | entries_per_page = PAGE_SIZE / sizeof(*rzs->table); |
| 1037 | num_table_pages = DIV_ROUND_UP(num_pages * sizeof(*rzs->table), |
| 1038 | PAGE_SIZE); |
| 1039 | /* |
| 1040 | * Set page->mapping to NULL for every table page. |
| 1041 | * Otherwise, we will hit bad_page() during free. |
| 1042 | */ |
| 1043 | while (rzs->num_extents && num_table_pages--) { |
| 1044 | struct page *page; |
| 1045 | page = vmalloc_to_page(&rzs->table[entry]); |
| 1046 | page->mapping = NULL; |
| 1047 | entry += entries_per_page; |
| 1048 | } |
| 1049 | vfree(rzs->table); |
| 1050 | rzs->table = NULL; |
| 1051 | |
| 1052 | xv_destroy_pool(rzs->mem_pool); |
| 1053 | rzs->mem_pool = NULL; |
| 1054 | |
| 1055 | /* Free all swap extent pages */ |
| 1056 | while (!list_empty(&rzs->backing_swap_extent_list)) { |
| 1057 | struct page *page; |
| 1058 | struct list_head *entry; |
| 1059 | entry = rzs->backing_swap_extent_list.next; |
| 1060 | page = list_entry(entry, struct page, lru); |
| 1061 | list_del(entry); |
| 1062 | __free_page(page); |
| 1063 | } |
| 1064 | INIT_LIST_HEAD(&rzs->backing_swap_extent_list); |
| 1065 | rzs->num_extents = 0; |
| 1066 | |
| 1067 | /* Close backing swap device, if present */ |
| 1068 | if (rzs->backing_swap) { |
| 1069 | if (is_backing_blkdev) |
| 1070 | bd_release(rzs->backing_swap); |
| 1071 | filp_close(rzs->swap_file, NULL); |
| 1072 | rzs->backing_swap = NULL; |
Nitin Gupta | c25d75a | 2010-01-28 21:19:59 +0530 | [diff] [blame] | 1073 | memset(rzs->backing_swap_name, 0, MAX_SWAP_NAME_LEN); |
Nitin Gupta | 306b0c9 | 2009-09-22 10:26:53 +0530 | [diff] [blame] | 1074 | } |
| 1075 | |
| 1076 | /* Reset stats */ |
| 1077 | memset(&rzs->stats, 0, sizeof(rzs->stats)); |
| 1078 | |
| 1079 | rzs->disksize = 0; |
| 1080 | rzs->memlimit = 0; |
Nitin Gupta | 306b0c9 | 2009-09-22 10:26:53 +0530 | [diff] [blame] | 1081 | } |
| 1082 | |
| 1083 | static int ramzswap_ioctl_init_device(struct ramzswap *rzs) |
| 1084 | { |
| 1085 | int ret; |
| 1086 | size_t num_pages; |
| 1087 | struct page *page; |
| 1088 | union swap_header *swap_header; |
| 1089 | |
| 1090 | if (rzs->init_done) { |
| 1091 | pr_info("Device already initialized!\n"); |
| 1092 | return -EBUSY; |
| 1093 | } |
| 1094 | |
| 1095 | ret = setup_backing_swap(rzs); |
| 1096 | if (ret) |
| 1097 | goto fail; |
| 1098 | |
| 1099 | if (rzs->backing_swap) |
| 1100 | ramzswap_set_memlimit(rzs, totalram_pages << PAGE_SHIFT); |
| 1101 | else |
| 1102 | ramzswap_set_disksize(rzs, totalram_pages << PAGE_SHIFT); |
| 1103 | |
| 1104 | rzs->compress_workmem = kzalloc(LZO1X_MEM_COMPRESS, GFP_KERNEL); |
| 1105 | if (!rzs->compress_workmem) { |
| 1106 | pr_err("Error allocating compressor working memory!\n"); |
| 1107 | ret = -ENOMEM; |
| 1108 | goto fail; |
| 1109 | } |
| 1110 | |
| 1111 | rzs->compress_buffer = (void *)__get_free_pages(__GFP_ZERO, 1); |
| 1112 | if (!rzs->compress_buffer) { |
| 1113 | pr_err("Error allocating compressor buffer space\n"); |
| 1114 | ret = -ENOMEM; |
| 1115 | goto fail; |
| 1116 | } |
| 1117 | |
| 1118 | num_pages = rzs->disksize >> PAGE_SHIFT; |
| 1119 | rzs->table = vmalloc(num_pages * sizeof(*rzs->table)); |
| 1120 | if (!rzs->table) { |
| 1121 | pr_err("Error allocating ramzswap address table\n"); |
| 1122 | /* To prevent accessing table entries during cleanup */ |
| 1123 | rzs->disksize = 0; |
| 1124 | ret = -ENOMEM; |
| 1125 | goto fail; |
| 1126 | } |
| 1127 | memset(rzs->table, 0, num_pages * sizeof(*rzs->table)); |
| 1128 | |
| 1129 | map_backing_swap_extents(rzs); |
| 1130 | |
| 1131 | page = alloc_page(__GFP_ZERO); |
| 1132 | if (!page) { |
| 1133 | pr_err("Error allocating swap header page\n"); |
| 1134 | ret = -ENOMEM; |
| 1135 | goto fail; |
| 1136 | } |
| 1137 | rzs->table[0].page = page; |
| 1138 | rzs_set_flag(rzs, 0, RZS_UNCOMPRESSED); |
| 1139 | |
| 1140 | swap_header = kmap(page); |
| 1141 | ret = setup_swap_header(rzs, swap_header); |
| 1142 | kunmap(page); |
| 1143 | if (ret) { |
| 1144 | pr_err("Error setting swap header\n"); |
| 1145 | goto fail; |
| 1146 | } |
| 1147 | |
| 1148 | set_capacity(rzs->disk, rzs->disksize >> SECTOR_SHIFT); |
| 1149 | |
| 1150 | /* |
| 1151 | * We have ident mapping of sectors for ramzswap and |
| 1152 | * and the backing swap device. So, this queue flag |
| 1153 | * should be according to backing dev. |
| 1154 | */ |
| 1155 | if (!rzs->backing_swap || |
| 1156 | blk_queue_nonrot(rzs->backing_swap->bd_disk->queue)) |
| 1157 | queue_flag_set_unlocked(QUEUE_FLAG_NONROT, rzs->disk->queue); |
| 1158 | |
| 1159 | rzs->mem_pool = xv_create_pool(); |
| 1160 | if (!rzs->mem_pool) { |
| 1161 | pr_err("Error creating memory pool\n"); |
| 1162 | ret = -ENOMEM; |
| 1163 | goto fail; |
| 1164 | } |
| 1165 | |
| 1166 | /* |
| 1167 | * Pages that compress to size greater than this are forwarded |
| 1168 | * to physical swap disk (if backing dev is provided) |
| 1169 | * TODO: make this configurable |
| 1170 | */ |
| 1171 | if (rzs->backing_swap) |
| 1172 | max_zpage_size = max_zpage_size_bdev; |
| 1173 | else |
| 1174 | max_zpage_size = max_zpage_size_nobdev; |
| 1175 | pr_debug("Max compressed page size: %u bytes\n", max_zpage_size); |
| 1176 | |
| 1177 | rzs->init_done = 1; |
| 1178 | |
| 1179 | pr_debug("Initialization done!\n"); |
| 1180 | return 0; |
| 1181 | |
| 1182 | fail: |
| 1183 | reset_device(rzs); |
| 1184 | |
| 1185 | pr_err("Initialization failed: err=%d\n", ret); |
| 1186 | return ret; |
| 1187 | } |
| 1188 | |
| 1189 | static int ramzswap_ioctl_reset_device(struct ramzswap *rzs) |
| 1190 | { |
| 1191 | if (rzs->init_done) |
| 1192 | reset_device(rzs); |
| 1193 | |
| 1194 | return 0; |
| 1195 | } |
| 1196 | |
| 1197 | static int ramzswap_ioctl(struct block_device *bdev, fmode_t mode, |
| 1198 | unsigned int cmd, unsigned long arg) |
| 1199 | { |
| 1200 | int ret = 0; |
| 1201 | size_t disksize_kb, memlimit_kb; |
| 1202 | |
| 1203 | struct ramzswap *rzs = bdev->bd_disk->private_data; |
| 1204 | |
| 1205 | switch (cmd) { |
| 1206 | case RZSIO_SET_DISKSIZE_KB: |
| 1207 | if (rzs->init_done) { |
| 1208 | ret = -EBUSY; |
| 1209 | goto out; |
| 1210 | } |
| 1211 | if (copy_from_user(&disksize_kb, (void *)arg, |
| 1212 | _IOC_SIZE(cmd))) { |
| 1213 | ret = -EFAULT; |
| 1214 | goto out; |
| 1215 | } |
| 1216 | rzs->disksize = disksize_kb << 10; |
| 1217 | pr_info("Disk size set to %zu kB\n", disksize_kb); |
| 1218 | break; |
| 1219 | |
| 1220 | case RZSIO_SET_MEMLIMIT_KB: |
| 1221 | if (rzs->init_done) { |
| 1222 | /* TODO: allow changing memlimit */ |
| 1223 | ret = -EBUSY; |
| 1224 | goto out; |
| 1225 | } |
| 1226 | if (copy_from_user(&memlimit_kb, (void *)arg, |
| 1227 | _IOC_SIZE(cmd))) { |
| 1228 | ret = -EFAULT; |
| 1229 | goto out; |
| 1230 | } |
| 1231 | rzs->memlimit = memlimit_kb << 10; |
| 1232 | pr_info("Memory limit set to %zu kB\n", memlimit_kb); |
| 1233 | break; |
| 1234 | |
| 1235 | case RZSIO_SET_BACKING_SWAP: |
| 1236 | if (rzs->init_done) { |
| 1237 | ret = -EBUSY; |
| 1238 | goto out; |
| 1239 | } |
| 1240 | |
| 1241 | if (copy_from_user(&rzs->backing_swap_name, (void *)arg, |
| 1242 | _IOC_SIZE(cmd))) { |
| 1243 | ret = -EFAULT; |
| 1244 | goto out; |
| 1245 | } |
| 1246 | rzs->backing_swap_name[MAX_SWAP_NAME_LEN - 1] = '\0'; |
| 1247 | pr_info("Backing swap set to %s\n", rzs->backing_swap_name); |
| 1248 | break; |
| 1249 | |
| 1250 | case RZSIO_GET_STATS: |
| 1251 | { |
| 1252 | struct ramzswap_ioctl_stats *stats; |
| 1253 | if (!rzs->init_done) { |
| 1254 | ret = -ENOTTY; |
| 1255 | goto out; |
| 1256 | } |
| 1257 | stats = kzalloc(sizeof(*stats), GFP_KERNEL); |
| 1258 | if (!stats) { |
| 1259 | ret = -ENOMEM; |
| 1260 | goto out; |
| 1261 | } |
| 1262 | ramzswap_ioctl_get_stats(rzs, stats); |
| 1263 | if (copy_to_user((void *)arg, stats, sizeof(*stats))) { |
| 1264 | kfree(stats); |
| 1265 | ret = -EFAULT; |
| 1266 | goto out; |
| 1267 | } |
| 1268 | kfree(stats); |
| 1269 | break; |
| 1270 | } |
| 1271 | case RZSIO_INIT: |
| 1272 | ret = ramzswap_ioctl_init_device(rzs); |
| 1273 | break; |
| 1274 | |
| 1275 | case RZSIO_RESET: |
| 1276 | /* Do not reset an active device! */ |
| 1277 | if (bdev->bd_holders) { |
| 1278 | ret = -EBUSY; |
| 1279 | goto out; |
| 1280 | } |
Nitin Gupta | 7eef753 | 2010-01-28 21:13:38 +0530 | [diff] [blame] | 1281 | |
| 1282 | /* Make sure all pending I/O is finished */ |
| 1283 | if (bdev) |
| 1284 | fsync_bdev(bdev); |
| 1285 | |
Nitin Gupta | 306b0c9 | 2009-09-22 10:26:53 +0530 | [diff] [blame] | 1286 | ret = ramzswap_ioctl_reset_device(rzs); |
| 1287 | break; |
| 1288 | |
| 1289 | default: |
| 1290 | pr_info("Invalid ioctl %u\n", cmd); |
| 1291 | ret = -ENOTTY; |
| 1292 | } |
| 1293 | |
| 1294 | out: |
| 1295 | return ret; |
| 1296 | } |
| 1297 | |
| 1298 | static struct block_device_operations ramzswap_devops = { |
| 1299 | .ioctl = ramzswap_ioctl, |
| 1300 | .owner = THIS_MODULE, |
| 1301 | }; |
| 1302 | |
Minchan Kim | 3bf040c | 2010-01-11 16:15:53 +0900 | [diff] [blame] | 1303 | static int create_device(struct ramzswap *rzs, int device_id) |
Nitin Gupta | 306b0c9 | 2009-09-22 10:26:53 +0530 | [diff] [blame] | 1304 | { |
Nitin Gupta | de1a21a | 2010-01-28 21:13:40 +0530 | [diff] [blame] | 1305 | int ret = 0; |
| 1306 | |
Nitin Gupta | 306b0c9 | 2009-09-22 10:26:53 +0530 | [diff] [blame] | 1307 | mutex_init(&rzs->lock); |
Nitin Gupta | 6a90772 | 2010-01-28 21:13:37 +0530 | [diff] [blame] | 1308 | spin_lock_init(&rzs->stat64_lock); |
Nitin Gupta | 306b0c9 | 2009-09-22 10:26:53 +0530 | [diff] [blame] | 1309 | INIT_LIST_HEAD(&rzs->backing_swap_extent_list); |
| 1310 | |
| 1311 | rzs->queue = blk_alloc_queue(GFP_KERNEL); |
| 1312 | if (!rzs->queue) { |
| 1313 | pr_err("Error allocating disk queue for device %d\n", |
| 1314 | device_id); |
Nitin Gupta | de1a21a | 2010-01-28 21:13:40 +0530 | [diff] [blame] | 1315 | ret = -ENOMEM; |
| 1316 | goto out; |
Nitin Gupta | 306b0c9 | 2009-09-22 10:26:53 +0530 | [diff] [blame] | 1317 | } |
| 1318 | |
| 1319 | blk_queue_make_request(rzs->queue, ramzswap_make_request); |
| 1320 | rzs->queue->queuedata = rzs; |
| 1321 | |
| 1322 | /* gendisk structure */ |
| 1323 | rzs->disk = alloc_disk(1); |
| 1324 | if (!rzs->disk) { |
| 1325 | blk_cleanup_queue(rzs->queue); |
| 1326 | pr_warning("Error allocating disk structure for device %d\n", |
| 1327 | device_id); |
Nitin Gupta | de1a21a | 2010-01-28 21:13:40 +0530 | [diff] [blame] | 1328 | ret = -ENOMEM; |
| 1329 | goto out; |
Nitin Gupta | 306b0c9 | 2009-09-22 10:26:53 +0530 | [diff] [blame] | 1330 | } |
| 1331 | |
| 1332 | rzs->disk->major = ramzswap_major; |
| 1333 | rzs->disk->first_minor = device_id; |
| 1334 | rzs->disk->fops = &ramzswap_devops; |
| 1335 | rzs->disk->queue = rzs->queue; |
| 1336 | rzs->disk->private_data = rzs; |
| 1337 | snprintf(rzs->disk->disk_name, 16, "ramzswap%d", device_id); |
| 1338 | |
| 1339 | /* |
| 1340 | * Actual capacity set using RZSIO_SET_DISKSIZE_KB ioctl |
| 1341 | * or set equal to backing swap device (if provided) |
| 1342 | */ |
| 1343 | set_capacity(rzs->disk, 0); |
Nitin Gupta | 5d83d5a | 2010-01-28 21:13:39 +0530 | [diff] [blame] | 1344 | |
| 1345 | blk_queue_physical_block_size(rzs->disk->queue, PAGE_SIZE); |
| 1346 | blk_queue_logical_block_size(rzs->disk->queue, PAGE_SIZE); |
| 1347 | |
Nitin Gupta | 306b0c9 | 2009-09-22 10:26:53 +0530 | [diff] [blame] | 1348 | add_disk(rzs->disk); |
| 1349 | |
| 1350 | rzs->init_done = 0; |
Nitin Gupta | de1a21a | 2010-01-28 21:13:40 +0530 | [diff] [blame] | 1351 | |
| 1352 | out: |
| 1353 | return ret; |
Nitin Gupta | 306b0c9 | 2009-09-22 10:26:53 +0530 | [diff] [blame] | 1354 | } |
| 1355 | |
| 1356 | static void destroy_device(struct ramzswap *rzs) |
| 1357 | { |
| 1358 | if (rzs->disk) { |
| 1359 | del_gendisk(rzs->disk); |
| 1360 | put_disk(rzs->disk); |
| 1361 | } |
| 1362 | |
| 1363 | if (rzs->queue) |
| 1364 | blk_cleanup_queue(rzs->queue); |
| 1365 | } |
| 1366 | |
| 1367 | static int __init ramzswap_init(void) |
| 1368 | { |
Nitin Gupta | de1a21a | 2010-01-28 21:13:40 +0530 | [diff] [blame] | 1369 | int ret, dev_id; |
Nitin Gupta | 306b0c9 | 2009-09-22 10:26:53 +0530 | [diff] [blame] | 1370 | |
| 1371 | if (num_devices > max_num_devices) { |
| 1372 | pr_warning("Invalid value for num_devices: %u\n", |
| 1373 | num_devices); |
Nitin Gupta | de1a21a | 2010-01-28 21:13:40 +0530 | [diff] [blame] | 1374 | ret = -EINVAL; |
| 1375 | goto out; |
Nitin Gupta | 306b0c9 | 2009-09-22 10:26:53 +0530 | [diff] [blame] | 1376 | } |
| 1377 | |
| 1378 | ramzswap_major = register_blkdev(0, "ramzswap"); |
| 1379 | if (ramzswap_major <= 0) { |
| 1380 | pr_warning("Unable to get major number\n"); |
Nitin Gupta | de1a21a | 2010-01-28 21:13:40 +0530 | [diff] [blame] | 1381 | ret = -EBUSY; |
| 1382 | goto out; |
Nitin Gupta | 306b0c9 | 2009-09-22 10:26:53 +0530 | [diff] [blame] | 1383 | } |
| 1384 | |
| 1385 | if (!num_devices) { |
| 1386 | pr_info("num_devices not specified. Using default: 1\n"); |
| 1387 | num_devices = 1; |
| 1388 | } |
| 1389 | |
| 1390 | /* Allocate the device array and initialize each one */ |
| 1391 | pr_info("Creating %u devices ...\n", num_devices); |
| 1392 | devices = kzalloc(num_devices * sizeof(struct ramzswap), GFP_KERNEL); |
Nitin Gupta | de1a21a | 2010-01-28 21:13:40 +0530 | [diff] [blame] | 1393 | if (!devices) { |
| 1394 | ret = -ENOMEM; |
| 1395 | goto unregister; |
| 1396 | } |
Nitin Gupta | 306b0c9 | 2009-09-22 10:26:53 +0530 | [diff] [blame] | 1397 | |
Nitin Gupta | de1a21a | 2010-01-28 21:13:40 +0530 | [diff] [blame] | 1398 | for (dev_id = 0; dev_id < num_devices; dev_id++) { |
| 1399 | ret = create_device(&devices[dev_id], dev_id); |
| 1400 | if (ret) |
Minchan Kim | 3bf040c | 2010-01-11 16:15:53 +0900 | [diff] [blame] | 1401 | goto free_devices; |
Nitin Gupta | de1a21a | 2010-01-28 21:13:40 +0530 | [diff] [blame] | 1402 | } |
| 1403 | |
Nitin Gupta | 306b0c9 | 2009-09-22 10:26:53 +0530 | [diff] [blame] | 1404 | return 0; |
Nitin Gupta | de1a21a | 2010-01-28 21:13:40 +0530 | [diff] [blame] | 1405 | |
Minchan Kim | 3bf040c | 2010-01-11 16:15:53 +0900 | [diff] [blame] | 1406 | free_devices: |
Nitin Gupta | de1a21a | 2010-01-28 21:13:40 +0530 | [diff] [blame] | 1407 | while (dev_id) |
| 1408 | destroy_device(&devices[--dev_id]); |
| 1409 | unregister: |
Nitin Gupta | 306b0c9 | 2009-09-22 10:26:53 +0530 | [diff] [blame] | 1410 | unregister_blkdev(ramzswap_major, "ramzswap"); |
Nitin Gupta | de1a21a | 2010-01-28 21:13:40 +0530 | [diff] [blame] | 1411 | out: |
Nitin Gupta | 306b0c9 | 2009-09-22 10:26:53 +0530 | [diff] [blame] | 1412 | return ret; |
| 1413 | } |
| 1414 | |
| 1415 | static void __exit ramzswap_exit(void) |
| 1416 | { |
| 1417 | int i; |
| 1418 | struct ramzswap *rzs; |
| 1419 | |
| 1420 | for (i = 0; i < num_devices; i++) { |
| 1421 | rzs = &devices[i]; |
| 1422 | |
| 1423 | destroy_device(rzs); |
| 1424 | if (rzs->init_done) |
| 1425 | reset_device(rzs); |
| 1426 | } |
| 1427 | |
| 1428 | unregister_blkdev(ramzswap_major, "ramzswap"); |
| 1429 | |
| 1430 | kfree(devices); |
| 1431 | pr_debug("Cleanup done!\n"); |
| 1432 | } |
| 1433 | |
| 1434 | module_param(num_devices, uint, 0); |
| 1435 | MODULE_PARM_DESC(num_devices, "Number of ramzswap devices"); |
| 1436 | |
| 1437 | module_init(ramzswap_init); |
| 1438 | module_exit(ramzswap_exit); |
| 1439 | |
| 1440 | MODULE_LICENSE("Dual BSD/GPL"); |
| 1441 | MODULE_AUTHOR("Nitin Gupta <ngupta@vflare.org>"); |
| 1442 | MODULE_DESCRIPTION("Compressed RAM Based Swap Device"); |