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Commit | Line | Data |
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1da177e4 LT |
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 | ||
1da177e4 LT |
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> | |
17 | #include <linux/shm.h> | |
18 | #include <linux/blkdev.h> | |
19 | #include <linux/writeback.h> | |
20 | #include <linux/proc_fs.h> | |
21 | #include <linux/seq_file.h> | |
22 | #include <linux/init.h> | |
23 | #include <linux/module.h> | |
24 | #include <linux/rmap.h> | |
25 | #include <linux/security.h> | |
26 | #include <linux/backing-dev.h> | |
fc0abb14 | 27 | #include <linux/mutex.h> |
c59ede7b | 28 | #include <linux/capability.h> |
1da177e4 | 29 | #include <linux/syscalls.h> |
8a9f3ccd | 30 | #include <linux/memcontrol.h> |
1da177e4 LT |
31 | |
32 | #include <asm/pgtable.h> | |
33 | #include <asm/tlbflush.h> | |
34 | #include <linux/swapops.h> | |
35 | ||
7c363b8c AB |
36 | static DEFINE_SPINLOCK(swap_lock); |
37 | static unsigned int nr_swapfiles; | |
b962716b | 38 | long nr_swap_pages; |
1da177e4 LT |
39 | long total_swap_pages; |
40 | static int swap_overflow; | |
78ecba08 | 41 | static int least_priority; |
1da177e4 | 42 | |
1da177e4 LT |
43 | static const char Bad_file[] = "Bad swap file entry "; |
44 | static const char Unused_file[] = "Unused swap file entry "; | |
45 | static const char Bad_offset[] = "Bad swap offset entry "; | |
46 | static const char Unused_offset[] = "Unused swap offset entry "; | |
47 | ||
7c363b8c | 48 | static struct swap_list_t swap_list = {-1, -1}; |
1da177e4 | 49 | |
f577eb30 | 50 | static struct swap_info_struct swap_info[MAX_SWAPFILES]; |
1da177e4 | 51 | |
fc0abb14 | 52 | static DEFINE_MUTEX(swapon_mutex); |
1da177e4 LT |
53 | |
54 | /* | |
55 | * We need this because the bdev->unplug_fn can sleep and we cannot | |
5d337b91 | 56 | * hold swap_lock while calling the unplug_fn. And swap_lock |
fc0abb14 | 57 | * cannot be turned into a mutex. |
1da177e4 LT |
58 | */ |
59 | static DECLARE_RWSEM(swap_unplug_sem); | |
60 | ||
1da177e4 LT |
61 | void swap_unplug_io_fn(struct backing_dev_info *unused_bdi, struct page *page) |
62 | { | |
63 | swp_entry_t entry; | |
64 | ||
65 | down_read(&swap_unplug_sem); | |
4c21e2f2 | 66 | entry.val = page_private(page); |
1da177e4 LT |
67 | if (PageSwapCache(page)) { |
68 | struct block_device *bdev = swap_info[swp_type(entry)].bdev; | |
69 | struct backing_dev_info *bdi; | |
70 | ||
71 | /* | |
72 | * If the page is removed from swapcache from under us (with a | |
73 | * racy try_to_unuse/swapoff) we need an additional reference | |
4c21e2f2 HD |
74 | * count to avoid reading garbage from page_private(page) above. |
75 | * If the WARN_ON triggers during a swapoff it maybe the race | |
1da177e4 LT |
76 | * condition and it's harmless. However if it triggers without |
77 | * swapoff it signals a problem. | |
78 | */ | |
79 | WARN_ON(page_count(page) <= 1); | |
80 | ||
81 | bdi = bdev->bd_inode->i_mapping->backing_dev_info; | |
ba32311e | 82 | blk_run_backing_dev(bdi, page); |
1da177e4 LT |
83 | } |
84 | up_read(&swap_unplug_sem); | |
85 | } | |
86 | ||
048c27fd HD |
87 | #define SWAPFILE_CLUSTER 256 |
88 | #define LATENCY_LIMIT 256 | |
89 | ||
6eb396dc | 90 | static inline unsigned long scan_swap_map(struct swap_info_struct *si) |
1da177e4 | 91 | { |
7dfad418 | 92 | unsigned long offset, last_in_cluster; |
048c27fd | 93 | int latency_ration = LATENCY_LIMIT; |
7dfad418 | 94 | |
1da177e4 | 95 | /* |
7dfad418 HD |
96 | * We try to cluster swap pages by allocating them sequentially |
97 | * in swap. Once we've allocated SWAPFILE_CLUSTER pages this | |
98 | * way, however, we resort to first-free allocation, starting | |
99 | * a new cluster. This prevents us from scattering swap pages | |
100 | * all over the entire swap partition, so that we reduce | |
101 | * overall disk seek times between swap pages. -- sct | |
102 | * But we do now try to find an empty cluster. -Andrea | |
103 | */ | |
104 | ||
52b7efdb | 105 | si->flags += SWP_SCANNING; |
7dfad418 HD |
106 | if (unlikely(!si->cluster_nr)) { |
107 | si->cluster_nr = SWAPFILE_CLUSTER - 1; | |
108 | if (si->pages - si->inuse_pages < SWAPFILE_CLUSTER) | |
109 | goto lowest; | |
5d337b91 | 110 | spin_unlock(&swap_lock); |
7dfad418 HD |
111 | |
112 | offset = si->lowest_bit; | |
113 | last_in_cluster = offset + SWAPFILE_CLUSTER - 1; | |
114 | ||
115 | /* Locate the first empty (unaligned) cluster */ | |
116 | for (; last_in_cluster <= si->highest_bit; offset++) { | |
1da177e4 | 117 | if (si->swap_map[offset]) |
7dfad418 HD |
118 | last_in_cluster = offset + SWAPFILE_CLUSTER; |
119 | else if (offset == last_in_cluster) { | |
5d337b91 | 120 | spin_lock(&swap_lock); |
9b65ef59 | 121 | si->cluster_next = offset-SWAPFILE_CLUSTER+1; |
7dfad418 | 122 | goto cluster; |
1da177e4 | 123 | } |
048c27fd HD |
124 | if (unlikely(--latency_ration < 0)) { |
125 | cond_resched(); | |
126 | latency_ration = LATENCY_LIMIT; | |
127 | } | |
7dfad418 | 128 | } |
5d337b91 | 129 | spin_lock(&swap_lock); |
7dfad418 | 130 | goto lowest; |
1da177e4 | 131 | } |
7dfad418 HD |
132 | |
133 | si->cluster_nr--; | |
134 | cluster: | |
135 | offset = si->cluster_next; | |
136 | if (offset > si->highest_bit) | |
137 | lowest: offset = si->lowest_bit; | |
52b7efdb HD |
138 | checks: if (!(si->flags & SWP_WRITEOK)) |
139 | goto no_page; | |
7dfad418 HD |
140 | if (!si->highest_bit) |
141 | goto no_page; | |
142 | if (!si->swap_map[offset]) { | |
52b7efdb | 143 | if (offset == si->lowest_bit) |
1da177e4 LT |
144 | si->lowest_bit++; |
145 | if (offset == si->highest_bit) | |
146 | si->highest_bit--; | |
7dfad418 HD |
147 | si->inuse_pages++; |
148 | if (si->inuse_pages == si->pages) { | |
1da177e4 LT |
149 | si->lowest_bit = si->max; |
150 | si->highest_bit = 0; | |
151 | } | |
152 | si->swap_map[offset] = 1; | |
7dfad418 | 153 | si->cluster_next = offset + 1; |
52b7efdb | 154 | si->flags -= SWP_SCANNING; |
1da177e4 LT |
155 | return offset; |
156 | } | |
7dfad418 | 157 | |
5d337b91 | 158 | spin_unlock(&swap_lock); |
7dfad418 | 159 | while (++offset <= si->highest_bit) { |
52b7efdb | 160 | if (!si->swap_map[offset]) { |
5d337b91 | 161 | spin_lock(&swap_lock); |
52b7efdb HD |
162 | goto checks; |
163 | } | |
048c27fd HD |
164 | if (unlikely(--latency_ration < 0)) { |
165 | cond_resched(); | |
166 | latency_ration = LATENCY_LIMIT; | |
167 | } | |
7dfad418 | 168 | } |
5d337b91 | 169 | spin_lock(&swap_lock); |
7dfad418 HD |
170 | goto lowest; |
171 | ||
172 | no_page: | |
52b7efdb | 173 | si->flags -= SWP_SCANNING; |
1da177e4 LT |
174 | return 0; |
175 | } | |
176 | ||
177 | swp_entry_t get_swap_page(void) | |
178 | { | |
fb4f88dc HD |
179 | struct swap_info_struct *si; |
180 | pgoff_t offset; | |
181 | int type, next; | |
182 | int wrapped = 0; | |
1da177e4 | 183 | |
5d337b91 | 184 | spin_lock(&swap_lock); |
1da177e4 | 185 | if (nr_swap_pages <= 0) |
fb4f88dc HD |
186 | goto noswap; |
187 | nr_swap_pages--; | |
188 | ||
189 | for (type = swap_list.next; type >= 0 && wrapped < 2; type = next) { | |
190 | si = swap_info + type; | |
191 | next = si->next; | |
192 | if (next < 0 || | |
193 | (!wrapped && si->prio != swap_info[next].prio)) { | |
194 | next = swap_list.head; | |
195 | wrapped++; | |
1da177e4 | 196 | } |
fb4f88dc HD |
197 | |
198 | if (!si->highest_bit) | |
199 | continue; | |
200 | if (!(si->flags & SWP_WRITEOK)) | |
201 | continue; | |
202 | ||
203 | swap_list.next = next; | |
fb4f88dc | 204 | offset = scan_swap_map(si); |
5d337b91 HD |
205 | if (offset) { |
206 | spin_unlock(&swap_lock); | |
fb4f88dc | 207 | return swp_entry(type, offset); |
5d337b91 | 208 | } |
fb4f88dc | 209 | next = swap_list.next; |
1da177e4 | 210 | } |
fb4f88dc HD |
211 | |
212 | nr_swap_pages++; | |
213 | noswap: | |
5d337b91 | 214 | spin_unlock(&swap_lock); |
fb4f88dc | 215 | return (swp_entry_t) {0}; |
1da177e4 LT |
216 | } |
217 | ||
3a291a20 RW |
218 | swp_entry_t get_swap_page_of_type(int type) |
219 | { | |
220 | struct swap_info_struct *si; | |
221 | pgoff_t offset; | |
222 | ||
223 | spin_lock(&swap_lock); | |
224 | si = swap_info + type; | |
225 | if (si->flags & SWP_WRITEOK) { | |
226 | nr_swap_pages--; | |
227 | offset = scan_swap_map(si); | |
228 | if (offset) { | |
229 | spin_unlock(&swap_lock); | |
230 | return swp_entry(type, offset); | |
231 | } | |
232 | nr_swap_pages++; | |
233 | } | |
234 | spin_unlock(&swap_lock); | |
235 | return (swp_entry_t) {0}; | |
236 | } | |
237 | ||
1da177e4 LT |
238 | static struct swap_info_struct * swap_info_get(swp_entry_t entry) |
239 | { | |
240 | struct swap_info_struct * p; | |
241 | unsigned long offset, type; | |
242 | ||
243 | if (!entry.val) | |
244 | goto out; | |
245 | type = swp_type(entry); | |
246 | if (type >= nr_swapfiles) | |
247 | goto bad_nofile; | |
248 | p = & swap_info[type]; | |
249 | if (!(p->flags & SWP_USED)) | |
250 | goto bad_device; | |
251 | offset = swp_offset(entry); | |
252 | if (offset >= p->max) | |
253 | goto bad_offset; | |
254 | if (!p->swap_map[offset]) | |
255 | goto bad_free; | |
5d337b91 | 256 | spin_lock(&swap_lock); |
1da177e4 LT |
257 | return p; |
258 | ||
259 | bad_free: | |
260 | printk(KERN_ERR "swap_free: %s%08lx\n", Unused_offset, entry.val); | |
261 | goto out; | |
262 | bad_offset: | |
263 | printk(KERN_ERR "swap_free: %s%08lx\n", Bad_offset, entry.val); | |
264 | goto out; | |
265 | bad_device: | |
266 | printk(KERN_ERR "swap_free: %s%08lx\n", Unused_file, entry.val); | |
267 | goto out; | |
268 | bad_nofile: | |
269 | printk(KERN_ERR "swap_free: %s%08lx\n", Bad_file, entry.val); | |
270 | out: | |
271 | return NULL; | |
272 | } | |
273 | ||
1da177e4 LT |
274 | static int swap_entry_free(struct swap_info_struct *p, unsigned long offset) |
275 | { | |
276 | int count = p->swap_map[offset]; | |
277 | ||
278 | if (count < SWAP_MAP_MAX) { | |
279 | count--; | |
280 | p->swap_map[offset] = count; | |
281 | if (!count) { | |
282 | if (offset < p->lowest_bit) | |
283 | p->lowest_bit = offset; | |
284 | if (offset > p->highest_bit) | |
285 | p->highest_bit = offset; | |
89d09a2c HD |
286 | if (p->prio > swap_info[swap_list.next].prio) |
287 | swap_list.next = p - swap_info; | |
1da177e4 LT |
288 | nr_swap_pages++; |
289 | p->inuse_pages--; | |
290 | } | |
291 | } | |
292 | return count; | |
293 | } | |
294 | ||
295 | /* | |
296 | * Caller has made sure that the swapdevice corresponding to entry | |
297 | * is still around or has not been recycled. | |
298 | */ | |
299 | void swap_free(swp_entry_t entry) | |
300 | { | |
301 | struct swap_info_struct * p; | |
302 | ||
303 | p = swap_info_get(entry); | |
304 | if (p) { | |
305 | swap_entry_free(p, swp_offset(entry)); | |
5d337b91 | 306 | spin_unlock(&swap_lock); |
1da177e4 LT |
307 | } |
308 | } | |
309 | ||
310 | /* | |
c475a8ab | 311 | * How many references to page are currently swapped out? |
1da177e4 | 312 | */ |
c475a8ab | 313 | static inline int page_swapcount(struct page *page) |
1da177e4 | 314 | { |
c475a8ab HD |
315 | int count = 0; |
316 | struct swap_info_struct *p; | |
1da177e4 LT |
317 | swp_entry_t entry; |
318 | ||
4c21e2f2 | 319 | entry.val = page_private(page); |
1da177e4 LT |
320 | p = swap_info_get(entry); |
321 | if (p) { | |
c475a8ab HD |
322 | /* Subtract the 1 for the swap cache itself */ |
323 | count = p->swap_map[swp_offset(entry)] - 1; | |
5d337b91 | 324 | spin_unlock(&swap_lock); |
1da177e4 | 325 | } |
c475a8ab | 326 | return count; |
1da177e4 LT |
327 | } |
328 | ||
329 | /* | |
7b1fe597 HD |
330 | * We can write to an anon page without COW if there are no other references |
331 | * to it. And as a side-effect, free up its swap: because the old content | |
332 | * on disk will never be read, and seeking back there to write new content | |
333 | * later would only waste time away from clustering. | |
1da177e4 | 334 | */ |
7b1fe597 | 335 | int reuse_swap_page(struct page *page) |
1da177e4 | 336 | { |
c475a8ab HD |
337 | int count; |
338 | ||
51726b12 | 339 | VM_BUG_ON(!PageLocked(page)); |
c475a8ab | 340 | count = page_mapcount(page); |
7b1fe597 | 341 | if (count <= 1 && PageSwapCache(page)) { |
c475a8ab | 342 | count += page_swapcount(page); |
7b1fe597 HD |
343 | if (count == 1 && !PageWriteback(page)) { |
344 | delete_from_swap_cache(page); | |
345 | SetPageDirty(page); | |
346 | } | |
347 | } | |
c475a8ab | 348 | return count == 1; |
1da177e4 LT |
349 | } |
350 | ||
351 | /* | |
a2c43eed HD |
352 | * If swap is getting full, or if there are no more mappings of this page, |
353 | * then try_to_free_swap is called to free its swap space. | |
1da177e4 | 354 | */ |
a2c43eed | 355 | int try_to_free_swap(struct page *page) |
1da177e4 | 356 | { |
51726b12 | 357 | VM_BUG_ON(!PageLocked(page)); |
1da177e4 LT |
358 | |
359 | if (!PageSwapCache(page)) | |
360 | return 0; | |
361 | if (PageWriteback(page)) | |
362 | return 0; | |
a2c43eed | 363 | if (page_swapcount(page)) |
1da177e4 LT |
364 | return 0; |
365 | ||
a2c43eed HD |
366 | delete_from_swap_cache(page); |
367 | SetPageDirty(page); | |
368 | return 1; | |
68a22394 RR |
369 | } |
370 | ||
1da177e4 LT |
371 | /* |
372 | * Free the swap entry like above, but also try to | |
373 | * free the page cache entry if it is the last user. | |
374 | */ | |
375 | void free_swap_and_cache(swp_entry_t entry) | |
376 | { | |
377 | struct swap_info_struct * p; | |
378 | struct page *page = NULL; | |
379 | ||
0697212a CL |
380 | if (is_migration_entry(entry)) |
381 | return; | |
382 | ||
1da177e4 LT |
383 | p = swap_info_get(entry); |
384 | if (p) { | |
93fac704 NP |
385 | if (swap_entry_free(p, swp_offset(entry)) == 1) { |
386 | page = find_get_page(&swapper_space, entry.val); | |
8413ac9d | 387 | if (page && !trylock_page(page)) { |
93fac704 NP |
388 | page_cache_release(page); |
389 | page = NULL; | |
390 | } | |
391 | } | |
5d337b91 | 392 | spin_unlock(&swap_lock); |
1da177e4 LT |
393 | } |
394 | if (page) { | |
a2c43eed HD |
395 | /* |
396 | * Not mapped elsewhere, or swap space full? Free it! | |
397 | * Also recheck PageSwapCache now page is locked (above). | |
398 | */ | |
93fac704 | 399 | if (PageSwapCache(page) && !PageWriteback(page) && |
a2c43eed | 400 | (!page_mapped(page) || vm_swap_full())) { |
1da177e4 LT |
401 | delete_from_swap_cache(page); |
402 | SetPageDirty(page); | |
403 | } | |
404 | unlock_page(page); | |
405 | page_cache_release(page); | |
406 | } | |
407 | } | |
408 | ||
b0cb1a19 | 409 | #ifdef CONFIG_HIBERNATION |
f577eb30 | 410 | /* |
915bae9e | 411 | * Find the swap type that corresponds to given device (if any). |
f577eb30 | 412 | * |
915bae9e RW |
413 | * @offset - number of the PAGE_SIZE-sized block of the device, starting |
414 | * from 0, in which the swap header is expected to be located. | |
415 | * | |
416 | * This is needed for the suspend to disk (aka swsusp). | |
f577eb30 | 417 | */ |
7bf23687 | 418 | int swap_type_of(dev_t device, sector_t offset, struct block_device **bdev_p) |
f577eb30 | 419 | { |
915bae9e | 420 | struct block_device *bdev = NULL; |
f577eb30 RW |
421 | int i; |
422 | ||
915bae9e RW |
423 | if (device) |
424 | bdev = bdget(device); | |
425 | ||
f577eb30 RW |
426 | spin_lock(&swap_lock); |
427 | for (i = 0; i < nr_swapfiles; i++) { | |
915bae9e | 428 | struct swap_info_struct *sis = swap_info + i; |
f577eb30 | 429 | |
915bae9e | 430 | if (!(sis->flags & SWP_WRITEOK)) |
f577eb30 | 431 | continue; |
b6b5bce3 | 432 | |
915bae9e | 433 | if (!bdev) { |
7bf23687 RW |
434 | if (bdev_p) |
435 | *bdev_p = sis->bdev; | |
436 | ||
6e1819d6 RW |
437 | spin_unlock(&swap_lock); |
438 | return i; | |
439 | } | |
915bae9e RW |
440 | if (bdev == sis->bdev) { |
441 | struct swap_extent *se; | |
442 | ||
443 | se = list_entry(sis->extent_list.next, | |
444 | struct swap_extent, list); | |
445 | if (se->start_block == offset) { | |
7bf23687 RW |
446 | if (bdev_p) |
447 | *bdev_p = sis->bdev; | |
448 | ||
915bae9e RW |
449 | spin_unlock(&swap_lock); |
450 | bdput(bdev); | |
451 | return i; | |
452 | } | |
f577eb30 RW |
453 | } |
454 | } | |
455 | spin_unlock(&swap_lock); | |
915bae9e RW |
456 | if (bdev) |
457 | bdput(bdev); | |
458 | ||
f577eb30 RW |
459 | return -ENODEV; |
460 | } | |
461 | ||
462 | /* | |
463 | * Return either the total number of swap pages of given type, or the number | |
464 | * of free pages of that type (depending on @free) | |
465 | * | |
466 | * This is needed for software suspend | |
467 | */ | |
468 | unsigned int count_swap_pages(int type, int free) | |
469 | { | |
470 | unsigned int n = 0; | |
471 | ||
472 | if (type < nr_swapfiles) { | |
473 | spin_lock(&swap_lock); | |
474 | if (swap_info[type].flags & SWP_WRITEOK) { | |
475 | n = swap_info[type].pages; | |
476 | if (free) | |
477 | n -= swap_info[type].inuse_pages; | |
478 | } | |
479 | spin_unlock(&swap_lock); | |
480 | } | |
481 | return n; | |
482 | } | |
483 | #endif | |
484 | ||
1da177e4 | 485 | /* |
72866f6f HD |
486 | * No need to decide whether this PTE shares the swap entry with others, |
487 | * just let do_wp_page work it out if a write is requested later - to | |
488 | * force COW, vm_page_prot omits write permission from any private vma. | |
1da177e4 | 489 | */ |
044d66c1 | 490 | static int unuse_pte(struct vm_area_struct *vma, pmd_t *pmd, |
1da177e4 LT |
491 | unsigned long addr, swp_entry_t entry, struct page *page) |
492 | { | |
044d66c1 HD |
493 | spinlock_t *ptl; |
494 | pte_t *pte; | |
495 | int ret = 1; | |
496 | ||
e1a1cd59 | 497 | if (mem_cgroup_charge(page, vma->vm_mm, GFP_KERNEL)) |
044d66c1 HD |
498 | ret = -ENOMEM; |
499 | ||
500 | pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl); | |
501 | if (unlikely(!pte_same(*pte, swp_entry_to_pte(entry)))) { | |
502 | if (ret > 0) | |
503 | mem_cgroup_uncharge_page(page); | |
504 | ret = 0; | |
505 | goto out; | |
506 | } | |
8a9f3ccd | 507 | |
4294621f | 508 | inc_mm_counter(vma->vm_mm, anon_rss); |
1da177e4 LT |
509 | get_page(page); |
510 | set_pte_at(vma->vm_mm, addr, pte, | |
511 | pte_mkold(mk_pte(page, vma->vm_page_prot))); | |
512 | page_add_anon_rmap(page, vma, addr); | |
513 | swap_free(entry); | |
514 | /* | |
515 | * Move the page to the active list so it is not | |
516 | * immediately swapped out again after swapon. | |
517 | */ | |
518 | activate_page(page); | |
044d66c1 HD |
519 | out: |
520 | pte_unmap_unlock(pte, ptl); | |
521 | return ret; | |
1da177e4 LT |
522 | } |
523 | ||
524 | static int unuse_pte_range(struct vm_area_struct *vma, pmd_t *pmd, | |
525 | unsigned long addr, unsigned long end, | |
526 | swp_entry_t entry, struct page *page) | |
527 | { | |
1da177e4 | 528 | pte_t swp_pte = swp_entry_to_pte(entry); |
705e87c0 | 529 | pte_t *pte; |
8a9f3ccd | 530 | int ret = 0; |
1da177e4 | 531 | |
044d66c1 HD |
532 | /* |
533 | * We don't actually need pte lock while scanning for swp_pte: since | |
534 | * we hold page lock and mmap_sem, swp_pte cannot be inserted into the | |
535 | * page table while we're scanning; though it could get zapped, and on | |
536 | * some architectures (e.g. x86_32 with PAE) we might catch a glimpse | |
537 | * of unmatched parts which look like swp_pte, so unuse_pte must | |
538 | * recheck under pte lock. Scanning without pte lock lets it be | |
539 | * preemptible whenever CONFIG_PREEMPT but not CONFIG_HIGHPTE. | |
540 | */ | |
541 | pte = pte_offset_map(pmd, addr); | |
1da177e4 LT |
542 | do { |
543 | /* | |
544 | * swapoff spends a _lot_ of time in this loop! | |
545 | * Test inline before going to call unuse_pte. | |
546 | */ | |
547 | if (unlikely(pte_same(*pte, swp_pte))) { | |
044d66c1 HD |
548 | pte_unmap(pte); |
549 | ret = unuse_pte(vma, pmd, addr, entry, page); | |
550 | if (ret) | |
551 | goto out; | |
552 | pte = pte_offset_map(pmd, addr); | |
1da177e4 LT |
553 | } |
554 | } while (pte++, addr += PAGE_SIZE, addr != end); | |
044d66c1 HD |
555 | pte_unmap(pte - 1); |
556 | out: | |
8a9f3ccd | 557 | return ret; |
1da177e4 LT |
558 | } |
559 | ||
560 | static inline int unuse_pmd_range(struct vm_area_struct *vma, pud_t *pud, | |
561 | unsigned long addr, unsigned long end, | |
562 | swp_entry_t entry, struct page *page) | |
563 | { | |
564 | pmd_t *pmd; | |
565 | unsigned long next; | |
8a9f3ccd | 566 | int ret; |
1da177e4 LT |
567 | |
568 | pmd = pmd_offset(pud, addr); | |
569 | do { | |
570 | next = pmd_addr_end(addr, end); | |
571 | if (pmd_none_or_clear_bad(pmd)) | |
572 | continue; | |
8a9f3ccd BS |
573 | ret = unuse_pte_range(vma, pmd, addr, next, entry, page); |
574 | if (ret) | |
575 | return ret; | |
1da177e4 LT |
576 | } while (pmd++, addr = next, addr != end); |
577 | return 0; | |
578 | } | |
579 | ||
580 | static inline int unuse_pud_range(struct vm_area_struct *vma, pgd_t *pgd, | |
581 | unsigned long addr, unsigned long end, | |
582 | swp_entry_t entry, struct page *page) | |
583 | { | |
584 | pud_t *pud; | |
585 | unsigned long next; | |
8a9f3ccd | 586 | int ret; |
1da177e4 LT |
587 | |
588 | pud = pud_offset(pgd, addr); | |
589 | do { | |
590 | next = pud_addr_end(addr, end); | |
591 | if (pud_none_or_clear_bad(pud)) | |
592 | continue; | |
8a9f3ccd BS |
593 | ret = unuse_pmd_range(vma, pud, addr, next, entry, page); |
594 | if (ret) | |
595 | return ret; | |
1da177e4 LT |
596 | } while (pud++, addr = next, addr != end); |
597 | return 0; | |
598 | } | |
599 | ||
600 | static int unuse_vma(struct vm_area_struct *vma, | |
601 | swp_entry_t entry, struct page *page) | |
602 | { | |
603 | pgd_t *pgd; | |
604 | unsigned long addr, end, next; | |
8a9f3ccd | 605 | int ret; |
1da177e4 LT |
606 | |
607 | if (page->mapping) { | |
608 | addr = page_address_in_vma(page, vma); | |
609 | if (addr == -EFAULT) | |
610 | return 0; | |
611 | else | |
612 | end = addr + PAGE_SIZE; | |
613 | } else { | |
614 | addr = vma->vm_start; | |
615 | end = vma->vm_end; | |
616 | } | |
617 | ||
618 | pgd = pgd_offset(vma->vm_mm, addr); | |
619 | do { | |
620 | next = pgd_addr_end(addr, end); | |
621 | if (pgd_none_or_clear_bad(pgd)) | |
622 | continue; | |
8a9f3ccd BS |
623 | ret = unuse_pud_range(vma, pgd, addr, next, entry, page); |
624 | if (ret) | |
625 | return ret; | |
1da177e4 LT |
626 | } while (pgd++, addr = next, addr != end); |
627 | return 0; | |
628 | } | |
629 | ||
630 | static int unuse_mm(struct mm_struct *mm, | |
631 | swp_entry_t entry, struct page *page) | |
632 | { | |
633 | struct vm_area_struct *vma; | |
8a9f3ccd | 634 | int ret = 0; |
1da177e4 LT |
635 | |
636 | if (!down_read_trylock(&mm->mmap_sem)) { | |
637 | /* | |
7d03431c FLVC |
638 | * Activate page so shrink_inactive_list is unlikely to unmap |
639 | * its ptes while lock is dropped, so swapoff can make progress. | |
1da177e4 | 640 | */ |
c475a8ab | 641 | activate_page(page); |
1da177e4 LT |
642 | unlock_page(page); |
643 | down_read(&mm->mmap_sem); | |
644 | lock_page(page); | |
645 | } | |
1da177e4 | 646 | for (vma = mm->mmap; vma; vma = vma->vm_next) { |
8a9f3ccd | 647 | if (vma->anon_vma && (ret = unuse_vma(vma, entry, page))) |
1da177e4 LT |
648 | break; |
649 | } | |
1da177e4 | 650 | up_read(&mm->mmap_sem); |
8a9f3ccd | 651 | return (ret < 0)? ret: 0; |
1da177e4 LT |
652 | } |
653 | ||
654 | /* | |
655 | * Scan swap_map from current position to next entry still in use. | |
656 | * Recycle to start on reaching the end, returning 0 when empty. | |
657 | */ | |
6eb396dc HD |
658 | static unsigned int find_next_to_unuse(struct swap_info_struct *si, |
659 | unsigned int prev) | |
1da177e4 | 660 | { |
6eb396dc HD |
661 | unsigned int max = si->max; |
662 | unsigned int i = prev; | |
1da177e4 LT |
663 | int count; |
664 | ||
665 | /* | |
5d337b91 | 666 | * No need for swap_lock here: we're just looking |
1da177e4 LT |
667 | * for whether an entry is in use, not modifying it; false |
668 | * hits are okay, and sys_swapoff() has already prevented new | |
5d337b91 | 669 | * allocations from this area (while holding swap_lock). |
1da177e4 LT |
670 | */ |
671 | for (;;) { | |
672 | if (++i >= max) { | |
673 | if (!prev) { | |
674 | i = 0; | |
675 | break; | |
676 | } | |
677 | /* | |
678 | * No entries in use at top of swap_map, | |
679 | * loop back to start and recheck there. | |
680 | */ | |
681 | max = prev + 1; | |
682 | prev = 0; | |
683 | i = 1; | |
684 | } | |
685 | count = si->swap_map[i]; | |
686 | if (count && count != SWAP_MAP_BAD) | |
687 | break; | |
688 | } | |
689 | return i; | |
690 | } | |
691 | ||
692 | /* | |
693 | * We completely avoid races by reading each swap page in advance, | |
694 | * and then search for the process using it. All the necessary | |
695 | * page table adjustments can then be made atomically. | |
696 | */ | |
697 | static int try_to_unuse(unsigned int type) | |
698 | { | |
699 | struct swap_info_struct * si = &swap_info[type]; | |
700 | struct mm_struct *start_mm; | |
701 | unsigned short *swap_map; | |
702 | unsigned short swcount; | |
703 | struct page *page; | |
704 | swp_entry_t entry; | |
6eb396dc | 705 | unsigned int i = 0; |
1da177e4 LT |
706 | int retval = 0; |
707 | int reset_overflow = 0; | |
708 | int shmem; | |
709 | ||
710 | /* | |
711 | * When searching mms for an entry, a good strategy is to | |
712 | * start at the first mm we freed the previous entry from | |
713 | * (though actually we don't notice whether we or coincidence | |
714 | * freed the entry). Initialize this start_mm with a hold. | |
715 | * | |
716 | * A simpler strategy would be to start at the last mm we | |
717 | * freed the previous entry from; but that would take less | |
718 | * advantage of mmlist ordering, which clusters forked mms | |
719 | * together, child after parent. If we race with dup_mmap(), we | |
720 | * prefer to resolve parent before child, lest we miss entries | |
721 | * duplicated after we scanned child: using last mm would invert | |
722 | * that. Though it's only a serious concern when an overflowed | |
723 | * swap count is reset from SWAP_MAP_MAX, preventing a rescan. | |
724 | */ | |
725 | start_mm = &init_mm; | |
726 | atomic_inc(&init_mm.mm_users); | |
727 | ||
728 | /* | |
729 | * Keep on scanning until all entries have gone. Usually, | |
730 | * one pass through swap_map is enough, but not necessarily: | |
731 | * there are races when an instance of an entry might be missed. | |
732 | */ | |
733 | while ((i = find_next_to_unuse(si, i)) != 0) { | |
734 | if (signal_pending(current)) { | |
735 | retval = -EINTR; | |
736 | break; | |
737 | } | |
738 | ||
739 | /* | |
740 | * Get a page for the entry, using the existing swap | |
741 | * cache page if there is one. Otherwise, get a clean | |
742 | * page and read the swap into it. | |
743 | */ | |
744 | swap_map = &si->swap_map[i]; | |
745 | entry = swp_entry(type, i); | |
02098fea HD |
746 | page = read_swap_cache_async(entry, |
747 | GFP_HIGHUSER_MOVABLE, NULL, 0); | |
1da177e4 LT |
748 | if (!page) { |
749 | /* | |
750 | * Either swap_duplicate() failed because entry | |
751 | * has been freed independently, and will not be | |
752 | * reused since sys_swapoff() already disabled | |
753 | * allocation from here, or alloc_page() failed. | |
754 | */ | |
755 | if (!*swap_map) | |
756 | continue; | |
757 | retval = -ENOMEM; | |
758 | break; | |
759 | } | |
760 | ||
761 | /* | |
762 | * Don't hold on to start_mm if it looks like exiting. | |
763 | */ | |
764 | if (atomic_read(&start_mm->mm_users) == 1) { | |
765 | mmput(start_mm); | |
766 | start_mm = &init_mm; | |
767 | atomic_inc(&init_mm.mm_users); | |
768 | } | |
769 | ||
770 | /* | |
771 | * Wait for and lock page. When do_swap_page races with | |
772 | * try_to_unuse, do_swap_page can handle the fault much | |
773 | * faster than try_to_unuse can locate the entry. This | |
774 | * apparently redundant "wait_on_page_locked" lets try_to_unuse | |
775 | * defer to do_swap_page in such a case - in some tests, | |
776 | * do_swap_page and try_to_unuse repeatedly compete. | |
777 | */ | |
778 | wait_on_page_locked(page); | |
779 | wait_on_page_writeback(page); | |
780 | lock_page(page); | |
781 | wait_on_page_writeback(page); | |
782 | ||
783 | /* | |
784 | * Remove all references to entry. | |
785 | * Whenever we reach init_mm, there's no address space | |
786 | * to search, but use it as a reminder to search shmem. | |
787 | */ | |
788 | shmem = 0; | |
789 | swcount = *swap_map; | |
790 | if (swcount > 1) { | |
791 | if (start_mm == &init_mm) | |
792 | shmem = shmem_unuse(entry, page); | |
793 | else | |
794 | retval = unuse_mm(start_mm, entry, page); | |
795 | } | |
796 | if (*swap_map > 1) { | |
797 | int set_start_mm = (*swap_map >= swcount); | |
798 | struct list_head *p = &start_mm->mmlist; | |
799 | struct mm_struct *new_start_mm = start_mm; | |
800 | struct mm_struct *prev_mm = start_mm; | |
801 | struct mm_struct *mm; | |
802 | ||
803 | atomic_inc(&new_start_mm->mm_users); | |
804 | atomic_inc(&prev_mm->mm_users); | |
805 | spin_lock(&mmlist_lock); | |
2e0e26c7 | 806 | while (*swap_map > 1 && !retval && !shmem && |
1da177e4 LT |
807 | (p = p->next) != &start_mm->mmlist) { |
808 | mm = list_entry(p, struct mm_struct, mmlist); | |
70af7c5c | 809 | if (!atomic_inc_not_zero(&mm->mm_users)) |
1da177e4 | 810 | continue; |
1da177e4 LT |
811 | spin_unlock(&mmlist_lock); |
812 | mmput(prev_mm); | |
813 | prev_mm = mm; | |
814 | ||
815 | cond_resched(); | |
816 | ||
817 | swcount = *swap_map; | |
818 | if (swcount <= 1) | |
819 | ; | |
820 | else if (mm == &init_mm) { | |
821 | set_start_mm = 1; | |
822 | shmem = shmem_unuse(entry, page); | |
823 | } else | |
824 | retval = unuse_mm(mm, entry, page); | |
825 | if (set_start_mm && *swap_map < swcount) { | |
826 | mmput(new_start_mm); | |
827 | atomic_inc(&mm->mm_users); | |
828 | new_start_mm = mm; | |
829 | set_start_mm = 0; | |
830 | } | |
831 | spin_lock(&mmlist_lock); | |
832 | } | |
833 | spin_unlock(&mmlist_lock); | |
834 | mmput(prev_mm); | |
835 | mmput(start_mm); | |
836 | start_mm = new_start_mm; | |
837 | } | |
2e0e26c7 HD |
838 | if (shmem) { |
839 | /* page has already been unlocked and released */ | |
840 | if (shmem > 0) | |
841 | continue; | |
842 | retval = shmem; | |
843 | break; | |
844 | } | |
1da177e4 LT |
845 | if (retval) { |
846 | unlock_page(page); | |
847 | page_cache_release(page); | |
848 | break; | |
849 | } | |
850 | ||
851 | /* | |
852 | * How could swap count reach 0x7fff when the maximum | |
853 | * pid is 0x7fff, and there's no way to repeat a swap | |
854 | * page within an mm (except in shmem, where it's the | |
855 | * shared object which takes the reference count)? | |
856 | * We believe SWAP_MAP_MAX cannot occur in Linux 2.4. | |
857 | * | |
858 | * If that's wrong, then we should worry more about | |
859 | * exit_mmap() and do_munmap() cases described above: | |
860 | * we might be resetting SWAP_MAP_MAX too early here. | |
861 | * We know "Undead"s can happen, they're okay, so don't | |
862 | * report them; but do report if we reset SWAP_MAP_MAX. | |
863 | */ | |
864 | if (*swap_map == SWAP_MAP_MAX) { | |
5d337b91 | 865 | spin_lock(&swap_lock); |
1da177e4 | 866 | *swap_map = 1; |
5d337b91 | 867 | spin_unlock(&swap_lock); |
1da177e4 LT |
868 | reset_overflow = 1; |
869 | } | |
870 | ||
871 | /* | |
872 | * If a reference remains (rare), we would like to leave | |
873 | * the page in the swap cache; but try_to_unmap could | |
874 | * then re-duplicate the entry once we drop page lock, | |
875 | * so we might loop indefinitely; also, that page could | |
876 | * not be swapped out to other storage meanwhile. So: | |
877 | * delete from cache even if there's another reference, | |
878 | * after ensuring that the data has been saved to disk - | |
879 | * since if the reference remains (rarer), it will be | |
880 | * read from disk into another page. Splitting into two | |
881 | * pages would be incorrect if swap supported "shared | |
882 | * private" pages, but they are handled by tmpfs files. | |
1da177e4 LT |
883 | */ |
884 | if ((*swap_map > 1) && PageDirty(page) && PageSwapCache(page)) { | |
885 | struct writeback_control wbc = { | |
886 | .sync_mode = WB_SYNC_NONE, | |
887 | }; | |
888 | ||
889 | swap_writepage(page, &wbc); | |
890 | lock_page(page); | |
891 | wait_on_page_writeback(page); | |
892 | } | |
68bdc8d6 HD |
893 | |
894 | /* | |
895 | * It is conceivable that a racing task removed this page from | |
896 | * swap cache just before we acquired the page lock at the top, | |
897 | * or while we dropped it in unuse_mm(). The page might even | |
898 | * be back in swap cache on another swap area: that we must not | |
899 | * delete, since it may not have been written out to swap yet. | |
900 | */ | |
901 | if (PageSwapCache(page) && | |
902 | likely(page_private(page) == entry.val)) | |
2e0e26c7 | 903 | delete_from_swap_cache(page); |
1da177e4 LT |
904 | |
905 | /* | |
906 | * So we could skip searching mms once swap count went | |
907 | * to 1, we did not mark any present ptes as dirty: must | |
2706a1b8 | 908 | * mark page dirty so shrink_page_list will preserve it. |
1da177e4 LT |
909 | */ |
910 | SetPageDirty(page); | |
911 | unlock_page(page); | |
912 | page_cache_release(page); | |
913 | ||
914 | /* | |
915 | * Make sure that we aren't completely killing | |
916 | * interactive performance. | |
917 | */ | |
918 | cond_resched(); | |
919 | } | |
920 | ||
921 | mmput(start_mm); | |
922 | if (reset_overflow) { | |
923 | printk(KERN_WARNING "swapoff: cleared swap entry overflow\n"); | |
924 | swap_overflow = 0; | |
925 | } | |
926 | return retval; | |
927 | } | |
928 | ||
929 | /* | |
5d337b91 HD |
930 | * After a successful try_to_unuse, if no swap is now in use, we know |
931 | * we can empty the mmlist. swap_lock must be held on entry and exit. | |
932 | * Note that mmlist_lock nests inside swap_lock, and an mm must be | |
1da177e4 LT |
933 | * added to the mmlist just after page_duplicate - before would be racy. |
934 | */ | |
935 | static void drain_mmlist(void) | |
936 | { | |
937 | struct list_head *p, *next; | |
938 | unsigned int i; | |
939 | ||
940 | for (i = 0; i < nr_swapfiles; i++) | |
941 | if (swap_info[i].inuse_pages) | |
942 | return; | |
943 | spin_lock(&mmlist_lock); | |
944 | list_for_each_safe(p, next, &init_mm.mmlist) | |
945 | list_del_init(p); | |
946 | spin_unlock(&mmlist_lock); | |
947 | } | |
948 | ||
949 | /* | |
950 | * Use this swapdev's extent info to locate the (PAGE_SIZE) block which | |
951 | * corresponds to page offset `offset'. | |
952 | */ | |
953 | sector_t map_swap_page(struct swap_info_struct *sis, pgoff_t offset) | |
954 | { | |
955 | struct swap_extent *se = sis->curr_swap_extent; | |
956 | struct swap_extent *start_se = se; | |
957 | ||
958 | for ( ; ; ) { | |
959 | struct list_head *lh; | |
960 | ||
961 | if (se->start_page <= offset && | |
962 | offset < (se->start_page + se->nr_pages)) { | |
963 | return se->start_block + (offset - se->start_page); | |
964 | } | |
11d31886 | 965 | lh = se->list.next; |
1da177e4 | 966 | if (lh == &sis->extent_list) |
11d31886 | 967 | lh = lh->next; |
1da177e4 LT |
968 | se = list_entry(lh, struct swap_extent, list); |
969 | sis->curr_swap_extent = se; | |
970 | BUG_ON(se == start_se); /* It *must* be present */ | |
971 | } | |
972 | } | |
973 | ||
b0cb1a19 | 974 | #ifdef CONFIG_HIBERNATION |
3aef83e0 RW |
975 | /* |
976 | * Get the (PAGE_SIZE) block corresponding to given offset on the swapdev | |
977 | * corresponding to given index in swap_info (swap type). | |
978 | */ | |
979 | sector_t swapdev_block(int swap_type, pgoff_t offset) | |
980 | { | |
981 | struct swap_info_struct *sis; | |
982 | ||
983 | if (swap_type >= nr_swapfiles) | |
984 | return 0; | |
985 | ||
986 | sis = swap_info + swap_type; | |
987 | return (sis->flags & SWP_WRITEOK) ? map_swap_page(sis, offset) : 0; | |
988 | } | |
b0cb1a19 | 989 | #endif /* CONFIG_HIBERNATION */ |
3aef83e0 | 990 | |
1da177e4 LT |
991 | /* |
992 | * Free all of a swapdev's extent information | |
993 | */ | |
994 | static void destroy_swap_extents(struct swap_info_struct *sis) | |
995 | { | |
996 | while (!list_empty(&sis->extent_list)) { | |
997 | struct swap_extent *se; | |
998 | ||
999 | se = list_entry(sis->extent_list.next, | |
1000 | struct swap_extent, list); | |
1001 | list_del(&se->list); | |
1002 | kfree(se); | |
1003 | } | |
1da177e4 LT |
1004 | } |
1005 | ||
1006 | /* | |
1007 | * Add a block range (and the corresponding page range) into this swapdev's | |
11d31886 | 1008 | * extent list. The extent list is kept sorted in page order. |
1da177e4 | 1009 | * |
11d31886 | 1010 | * This function rather assumes that it is called in ascending page order. |
1da177e4 LT |
1011 | */ |
1012 | static int | |
1013 | add_swap_extent(struct swap_info_struct *sis, unsigned long start_page, | |
1014 | unsigned long nr_pages, sector_t start_block) | |
1015 | { | |
1016 | struct swap_extent *se; | |
1017 | struct swap_extent *new_se; | |
1018 | struct list_head *lh; | |
1019 | ||
11d31886 HD |
1020 | lh = sis->extent_list.prev; /* The highest page extent */ |
1021 | if (lh != &sis->extent_list) { | |
1da177e4 | 1022 | se = list_entry(lh, struct swap_extent, list); |
11d31886 HD |
1023 | BUG_ON(se->start_page + se->nr_pages != start_page); |
1024 | if (se->start_block + se->nr_pages == start_block) { | |
1da177e4 LT |
1025 | /* Merge it */ |
1026 | se->nr_pages += nr_pages; | |
1027 | return 0; | |
1028 | } | |
1da177e4 LT |
1029 | } |
1030 | ||
1031 | /* | |
1032 | * No merge. Insert a new extent, preserving ordering. | |
1033 | */ | |
1034 | new_se = kmalloc(sizeof(*se), GFP_KERNEL); | |
1035 | if (new_se == NULL) | |
1036 | return -ENOMEM; | |
1037 | new_se->start_page = start_page; | |
1038 | new_se->nr_pages = nr_pages; | |
1039 | new_se->start_block = start_block; | |
1040 | ||
11d31886 | 1041 | list_add_tail(&new_se->list, &sis->extent_list); |
53092a74 | 1042 | return 1; |
1da177e4 LT |
1043 | } |
1044 | ||
1045 | /* | |
1046 | * A `swap extent' is a simple thing which maps a contiguous range of pages | |
1047 | * onto a contiguous range of disk blocks. An ordered list of swap extents | |
1048 | * is built at swapon time and is then used at swap_writepage/swap_readpage | |
1049 | * time for locating where on disk a page belongs. | |
1050 | * | |
1051 | * If the swapfile is an S_ISBLK block device, a single extent is installed. | |
1052 | * This is done so that the main operating code can treat S_ISBLK and S_ISREG | |
1053 | * swap files identically. | |
1054 | * | |
1055 | * Whether the swapdev is an S_ISREG file or an S_ISBLK blockdev, the swap | |
1056 | * extent list operates in PAGE_SIZE disk blocks. Both S_ISREG and S_ISBLK | |
1057 | * swapfiles are handled *identically* after swapon time. | |
1058 | * | |
1059 | * For S_ISREG swapfiles, setup_swap_extents() will walk all the file's blocks | |
1060 | * and will parse them into an ordered extent list, in PAGE_SIZE chunks. If | |
1061 | * some stray blocks are found which do not fall within the PAGE_SIZE alignment | |
1062 | * requirements, they are simply tossed out - we will never use those blocks | |
1063 | * for swapping. | |
1064 | * | |
b0d9bcd4 | 1065 | * For S_ISREG swapfiles we set S_SWAPFILE across the life of the swapon. This |
1da177e4 LT |
1066 | * prevents root from shooting her foot off by ftruncating an in-use swapfile, |
1067 | * which will scribble on the fs. | |
1068 | * | |
1069 | * The amount of disk space which a single swap extent represents varies. | |
1070 | * Typically it is in the 1-4 megabyte range. So we can have hundreds of | |
1071 | * extents in the list. To avoid much list walking, we cache the previous | |
1072 | * search location in `curr_swap_extent', and start new searches from there. | |
1073 | * This is extremely effective. The average number of iterations in | |
1074 | * map_swap_page() has been measured at about 0.3 per page. - akpm. | |
1075 | */ | |
53092a74 | 1076 | static int setup_swap_extents(struct swap_info_struct *sis, sector_t *span) |
1da177e4 LT |
1077 | { |
1078 | struct inode *inode; | |
1079 | unsigned blocks_per_page; | |
1080 | unsigned long page_no; | |
1081 | unsigned blkbits; | |
1082 | sector_t probe_block; | |
1083 | sector_t last_block; | |
53092a74 HD |
1084 | sector_t lowest_block = -1; |
1085 | sector_t highest_block = 0; | |
1086 | int nr_extents = 0; | |
1da177e4 LT |
1087 | int ret; |
1088 | ||
1089 | inode = sis->swap_file->f_mapping->host; | |
1090 | if (S_ISBLK(inode->i_mode)) { | |
1091 | ret = add_swap_extent(sis, 0, sis->max, 0); | |
53092a74 | 1092 | *span = sis->pages; |
1da177e4 LT |
1093 | goto done; |
1094 | } | |
1095 | ||
1096 | blkbits = inode->i_blkbits; | |
1097 | blocks_per_page = PAGE_SIZE >> blkbits; | |
1098 | ||
1099 | /* | |
1100 | * Map all the blocks into the extent list. This code doesn't try | |
1101 | * to be very smart. | |
1102 | */ | |
1103 | probe_block = 0; | |
1104 | page_no = 0; | |
1105 | last_block = i_size_read(inode) >> blkbits; | |
1106 | while ((probe_block + blocks_per_page) <= last_block && | |
1107 | page_no < sis->max) { | |
1108 | unsigned block_in_page; | |
1109 | sector_t first_block; | |
1110 | ||
1111 | first_block = bmap(inode, probe_block); | |
1112 | if (first_block == 0) | |
1113 | goto bad_bmap; | |
1114 | ||
1115 | /* | |
1116 | * It must be PAGE_SIZE aligned on-disk | |
1117 | */ | |
1118 | if (first_block & (blocks_per_page - 1)) { | |
1119 | probe_block++; | |
1120 | goto reprobe; | |
1121 | } | |
1122 | ||
1123 | for (block_in_page = 1; block_in_page < blocks_per_page; | |
1124 | block_in_page++) { | |
1125 | sector_t block; | |
1126 | ||
1127 | block = bmap(inode, probe_block + block_in_page); | |
1128 | if (block == 0) | |
1129 | goto bad_bmap; | |
1130 | if (block != first_block + block_in_page) { | |
1131 | /* Discontiguity */ | |
1132 | probe_block++; | |
1133 | goto reprobe; | |
1134 | } | |
1135 | } | |
1136 | ||
53092a74 HD |
1137 | first_block >>= (PAGE_SHIFT - blkbits); |
1138 | if (page_no) { /* exclude the header page */ | |
1139 | if (first_block < lowest_block) | |
1140 | lowest_block = first_block; | |
1141 | if (first_block > highest_block) | |
1142 | highest_block = first_block; | |
1143 | } | |
1144 | ||
1da177e4 LT |
1145 | /* |
1146 | * We found a PAGE_SIZE-length, PAGE_SIZE-aligned run of blocks | |
1147 | */ | |
53092a74 HD |
1148 | ret = add_swap_extent(sis, page_no, 1, first_block); |
1149 | if (ret < 0) | |
1da177e4 | 1150 | goto out; |
53092a74 | 1151 | nr_extents += ret; |
1da177e4 LT |
1152 | page_no++; |
1153 | probe_block += blocks_per_page; | |
1154 | reprobe: | |
1155 | continue; | |
1156 | } | |
53092a74 HD |
1157 | ret = nr_extents; |
1158 | *span = 1 + highest_block - lowest_block; | |
1da177e4 | 1159 | if (page_no == 0) |
e2244ec2 | 1160 | page_no = 1; /* force Empty message */ |
1da177e4 | 1161 | sis->max = page_no; |
e2244ec2 | 1162 | sis->pages = page_no - 1; |
1da177e4 LT |
1163 | sis->highest_bit = page_no - 1; |
1164 | done: | |
1165 | sis->curr_swap_extent = list_entry(sis->extent_list.prev, | |
1166 | struct swap_extent, list); | |
1167 | goto out; | |
1168 | bad_bmap: | |
1169 | printk(KERN_ERR "swapon: swapfile has holes\n"); | |
1170 | ret = -EINVAL; | |
1171 | out: | |
1172 | return ret; | |
1173 | } | |
1174 | ||
1175 | #if 0 /* We don't need this yet */ | |
1176 | #include <linux/backing-dev.h> | |
1177 | int page_queue_congested(struct page *page) | |
1178 | { | |
1179 | struct backing_dev_info *bdi; | |
1180 | ||
51726b12 | 1181 | VM_BUG_ON(!PageLocked(page)); /* It pins the swap_info_struct */ |
1da177e4 LT |
1182 | |
1183 | if (PageSwapCache(page)) { | |
4c21e2f2 | 1184 | swp_entry_t entry = { .val = page_private(page) }; |
1da177e4 LT |
1185 | struct swap_info_struct *sis; |
1186 | ||
1187 | sis = get_swap_info_struct(swp_type(entry)); | |
1188 | bdi = sis->bdev->bd_inode->i_mapping->backing_dev_info; | |
1189 | } else | |
1190 | bdi = page->mapping->backing_dev_info; | |
1191 | return bdi_write_congested(bdi); | |
1192 | } | |
1193 | #endif | |
1194 | ||
1195 | asmlinkage long sys_swapoff(const char __user * specialfile) | |
1196 | { | |
1197 | struct swap_info_struct * p = NULL; | |
1198 | unsigned short *swap_map; | |
1199 | struct file *swap_file, *victim; | |
1200 | struct address_space *mapping; | |
1201 | struct inode *inode; | |
1202 | char * pathname; | |
1203 | int i, type, prev; | |
1204 | int err; | |
1205 | ||
1206 | if (!capable(CAP_SYS_ADMIN)) | |
1207 | return -EPERM; | |
1208 | ||
1209 | pathname = getname(specialfile); | |
1210 | err = PTR_ERR(pathname); | |
1211 | if (IS_ERR(pathname)) | |
1212 | goto out; | |
1213 | ||
1214 | victim = filp_open(pathname, O_RDWR|O_LARGEFILE, 0); | |
1215 | putname(pathname); | |
1216 | err = PTR_ERR(victim); | |
1217 | if (IS_ERR(victim)) | |
1218 | goto out; | |
1219 | ||
1220 | mapping = victim->f_mapping; | |
1221 | prev = -1; | |
5d337b91 | 1222 | spin_lock(&swap_lock); |
1da177e4 LT |
1223 | for (type = swap_list.head; type >= 0; type = swap_info[type].next) { |
1224 | p = swap_info + type; | |
1225 | if ((p->flags & SWP_ACTIVE) == SWP_ACTIVE) { | |
1226 | if (p->swap_file->f_mapping == mapping) | |
1227 | break; | |
1228 | } | |
1229 | prev = type; | |
1230 | } | |
1231 | if (type < 0) { | |
1232 | err = -EINVAL; | |
5d337b91 | 1233 | spin_unlock(&swap_lock); |
1da177e4 LT |
1234 | goto out_dput; |
1235 | } | |
1236 | if (!security_vm_enough_memory(p->pages)) | |
1237 | vm_unacct_memory(p->pages); | |
1238 | else { | |
1239 | err = -ENOMEM; | |
5d337b91 | 1240 | spin_unlock(&swap_lock); |
1da177e4 LT |
1241 | goto out_dput; |
1242 | } | |
1243 | if (prev < 0) { | |
1244 | swap_list.head = p->next; | |
1245 | } else { | |
1246 | swap_info[prev].next = p->next; | |
1247 | } | |
1248 | if (type == swap_list.next) { | |
1249 | /* just pick something that's safe... */ | |
1250 | swap_list.next = swap_list.head; | |
1251 | } | |
78ecba08 HD |
1252 | if (p->prio < 0) { |
1253 | for (i = p->next; i >= 0; i = swap_info[i].next) | |
1254 | swap_info[i].prio = p->prio--; | |
1255 | least_priority++; | |
1256 | } | |
1da177e4 LT |
1257 | nr_swap_pages -= p->pages; |
1258 | total_swap_pages -= p->pages; | |
1259 | p->flags &= ~SWP_WRITEOK; | |
5d337b91 | 1260 | spin_unlock(&swap_lock); |
fb4f88dc | 1261 | |
1da177e4 LT |
1262 | current->flags |= PF_SWAPOFF; |
1263 | err = try_to_unuse(type); | |
1264 | current->flags &= ~PF_SWAPOFF; | |
1265 | ||
1da177e4 LT |
1266 | if (err) { |
1267 | /* re-insert swap space back into swap_list */ | |
5d337b91 | 1268 | spin_lock(&swap_lock); |
78ecba08 HD |
1269 | if (p->prio < 0) |
1270 | p->prio = --least_priority; | |
1271 | prev = -1; | |
1272 | for (i = swap_list.head; i >= 0; i = swap_info[i].next) { | |
1da177e4 LT |
1273 | if (p->prio >= swap_info[i].prio) |
1274 | break; | |
78ecba08 HD |
1275 | prev = i; |
1276 | } | |
1da177e4 LT |
1277 | p->next = i; |
1278 | if (prev < 0) | |
1279 | swap_list.head = swap_list.next = p - swap_info; | |
1280 | else | |
1281 | swap_info[prev].next = p - swap_info; | |
1282 | nr_swap_pages += p->pages; | |
1283 | total_swap_pages += p->pages; | |
1284 | p->flags |= SWP_WRITEOK; | |
5d337b91 | 1285 | spin_unlock(&swap_lock); |
1da177e4 LT |
1286 | goto out_dput; |
1287 | } | |
52b7efdb HD |
1288 | |
1289 | /* wait for any unplug function to finish */ | |
1290 | down_write(&swap_unplug_sem); | |
1291 | up_write(&swap_unplug_sem); | |
1292 | ||
5d337b91 | 1293 | destroy_swap_extents(p); |
fc0abb14 | 1294 | mutex_lock(&swapon_mutex); |
5d337b91 HD |
1295 | spin_lock(&swap_lock); |
1296 | drain_mmlist(); | |
1297 | ||
52b7efdb | 1298 | /* wait for anyone still in scan_swap_map */ |
52b7efdb HD |
1299 | p->highest_bit = 0; /* cuts scans short */ |
1300 | while (p->flags >= SWP_SCANNING) { | |
5d337b91 | 1301 | spin_unlock(&swap_lock); |
13e4b57f | 1302 | schedule_timeout_uninterruptible(1); |
5d337b91 | 1303 | spin_lock(&swap_lock); |
52b7efdb | 1304 | } |
52b7efdb | 1305 | |
1da177e4 LT |
1306 | swap_file = p->swap_file; |
1307 | p->swap_file = NULL; | |
1308 | p->max = 0; | |
1309 | swap_map = p->swap_map; | |
1310 | p->swap_map = NULL; | |
1311 | p->flags = 0; | |
5d337b91 | 1312 | spin_unlock(&swap_lock); |
fc0abb14 | 1313 | mutex_unlock(&swapon_mutex); |
1da177e4 LT |
1314 | vfree(swap_map); |
1315 | inode = mapping->host; | |
1316 | if (S_ISBLK(inode->i_mode)) { | |
1317 | struct block_device *bdev = I_BDEV(inode); | |
1318 | set_blocksize(bdev, p->old_block_size); | |
1319 | bd_release(bdev); | |
1320 | } else { | |
1b1dcc1b | 1321 | mutex_lock(&inode->i_mutex); |
1da177e4 | 1322 | inode->i_flags &= ~S_SWAPFILE; |
1b1dcc1b | 1323 | mutex_unlock(&inode->i_mutex); |
1da177e4 LT |
1324 | } |
1325 | filp_close(swap_file, NULL); | |
1326 | err = 0; | |
1327 | ||
1328 | out_dput: | |
1329 | filp_close(victim, NULL); | |
1330 | out: | |
1331 | return err; | |
1332 | } | |
1333 | ||
1334 | #ifdef CONFIG_PROC_FS | |
1335 | /* iterator */ | |
1336 | static void *swap_start(struct seq_file *swap, loff_t *pos) | |
1337 | { | |
1338 | struct swap_info_struct *ptr = swap_info; | |
1339 | int i; | |
1340 | loff_t l = *pos; | |
1341 | ||
fc0abb14 | 1342 | mutex_lock(&swapon_mutex); |
1da177e4 | 1343 | |
881e4aab SS |
1344 | if (!l) |
1345 | return SEQ_START_TOKEN; | |
1346 | ||
1da177e4 LT |
1347 | for (i = 0; i < nr_swapfiles; i++, ptr++) { |
1348 | if (!(ptr->flags & SWP_USED) || !ptr->swap_map) | |
1349 | continue; | |
881e4aab | 1350 | if (!--l) |
1da177e4 LT |
1351 | return ptr; |
1352 | } | |
1353 | ||
1354 | return NULL; | |
1355 | } | |
1356 | ||
1357 | static void *swap_next(struct seq_file *swap, void *v, loff_t *pos) | |
1358 | { | |
881e4aab | 1359 | struct swap_info_struct *ptr; |
1da177e4 LT |
1360 | struct swap_info_struct *endptr = swap_info + nr_swapfiles; |
1361 | ||
881e4aab SS |
1362 | if (v == SEQ_START_TOKEN) |
1363 | ptr = swap_info; | |
1364 | else { | |
1365 | ptr = v; | |
1366 | ptr++; | |
1367 | } | |
1368 | ||
1369 | for (; ptr < endptr; ptr++) { | |
1da177e4 LT |
1370 | if (!(ptr->flags & SWP_USED) || !ptr->swap_map) |
1371 | continue; | |
1372 | ++*pos; | |
1373 | return ptr; | |
1374 | } | |
1375 | ||
1376 | return NULL; | |
1377 | } | |
1378 | ||
1379 | static void swap_stop(struct seq_file *swap, void *v) | |
1380 | { | |
fc0abb14 | 1381 | mutex_unlock(&swapon_mutex); |
1da177e4 LT |
1382 | } |
1383 | ||
1384 | static int swap_show(struct seq_file *swap, void *v) | |
1385 | { | |
1386 | struct swap_info_struct *ptr = v; | |
1387 | struct file *file; | |
1388 | int len; | |
1389 | ||
881e4aab SS |
1390 | if (ptr == SEQ_START_TOKEN) { |
1391 | seq_puts(swap,"Filename\t\t\t\tType\t\tSize\tUsed\tPriority\n"); | |
1392 | return 0; | |
1393 | } | |
1da177e4 LT |
1394 | |
1395 | file = ptr->swap_file; | |
c32c2f63 | 1396 | len = seq_path(swap, &file->f_path, " \t\n\\"); |
6eb396dc | 1397 | seq_printf(swap, "%*s%s\t%u\t%u\t%d\n", |
1da177e4 | 1398 | len < 40 ? 40 - len : 1, " ", |
d3ac7f89 | 1399 | S_ISBLK(file->f_path.dentry->d_inode->i_mode) ? |
1da177e4 LT |
1400 | "partition" : "file\t", |
1401 | ptr->pages << (PAGE_SHIFT - 10), | |
1402 | ptr->inuse_pages << (PAGE_SHIFT - 10), | |
1403 | ptr->prio); | |
1404 | return 0; | |
1405 | } | |
1406 | ||
15ad7cdc | 1407 | static const struct seq_operations swaps_op = { |
1da177e4 LT |
1408 | .start = swap_start, |
1409 | .next = swap_next, | |
1410 | .stop = swap_stop, | |
1411 | .show = swap_show | |
1412 | }; | |
1413 | ||
1414 | static int swaps_open(struct inode *inode, struct file *file) | |
1415 | { | |
1416 | return seq_open(file, &swaps_op); | |
1417 | } | |
1418 | ||
15ad7cdc | 1419 | static const struct file_operations proc_swaps_operations = { |
1da177e4 LT |
1420 | .open = swaps_open, |
1421 | .read = seq_read, | |
1422 | .llseek = seq_lseek, | |
1423 | .release = seq_release, | |
1424 | }; | |
1425 | ||
1426 | static int __init procswaps_init(void) | |
1427 | { | |
3d71f86f | 1428 | proc_create("swaps", 0, NULL, &proc_swaps_operations); |
1da177e4 LT |
1429 | return 0; |
1430 | } | |
1431 | __initcall(procswaps_init); | |
1432 | #endif /* CONFIG_PROC_FS */ | |
1433 | ||
1796316a JB |
1434 | #ifdef MAX_SWAPFILES_CHECK |
1435 | static int __init max_swapfiles_check(void) | |
1436 | { | |
1437 | MAX_SWAPFILES_CHECK(); | |
1438 | return 0; | |
1439 | } | |
1440 | late_initcall(max_swapfiles_check); | |
1441 | #endif | |
1442 | ||
1da177e4 LT |
1443 | /* |
1444 | * Written 01/25/92 by Simmule Turner, heavily changed by Linus. | |
1445 | * | |
1446 | * The swapon system call | |
1447 | */ | |
1448 | asmlinkage long sys_swapon(const char __user * specialfile, int swap_flags) | |
1449 | { | |
1450 | struct swap_info_struct * p; | |
1451 | char *name = NULL; | |
1452 | struct block_device *bdev = NULL; | |
1453 | struct file *swap_file = NULL; | |
1454 | struct address_space *mapping; | |
1455 | unsigned int type; | |
1456 | int i, prev; | |
1457 | int error; | |
1da177e4 LT |
1458 | union swap_header *swap_header = NULL; |
1459 | int swap_header_version; | |
6eb396dc HD |
1460 | unsigned int nr_good_pages = 0; |
1461 | int nr_extents = 0; | |
53092a74 | 1462 | sector_t span; |
1da177e4 | 1463 | unsigned long maxpages = 1; |
73fd8748 | 1464 | unsigned long swapfilepages; |
78ecba08 | 1465 | unsigned short *swap_map = NULL; |
1da177e4 LT |
1466 | struct page *page = NULL; |
1467 | struct inode *inode = NULL; | |
1468 | int did_down = 0; | |
1469 | ||
1470 | if (!capable(CAP_SYS_ADMIN)) | |
1471 | return -EPERM; | |
5d337b91 | 1472 | spin_lock(&swap_lock); |
1da177e4 LT |
1473 | p = swap_info; |
1474 | for (type = 0 ; type < nr_swapfiles ; type++,p++) | |
1475 | if (!(p->flags & SWP_USED)) | |
1476 | break; | |
1477 | error = -EPERM; | |
0697212a | 1478 | if (type >= MAX_SWAPFILES) { |
5d337b91 | 1479 | spin_unlock(&swap_lock); |
1da177e4 LT |
1480 | goto out; |
1481 | } | |
1482 | if (type >= nr_swapfiles) | |
1483 | nr_swapfiles = type+1; | |
78ecba08 | 1484 | memset(p, 0, sizeof(*p)); |
1da177e4 LT |
1485 | INIT_LIST_HEAD(&p->extent_list); |
1486 | p->flags = SWP_USED; | |
1da177e4 | 1487 | p->next = -1; |
5d337b91 | 1488 | spin_unlock(&swap_lock); |
1da177e4 LT |
1489 | name = getname(specialfile); |
1490 | error = PTR_ERR(name); | |
1491 | if (IS_ERR(name)) { | |
1492 | name = NULL; | |
1493 | goto bad_swap_2; | |
1494 | } | |
1495 | swap_file = filp_open(name, O_RDWR|O_LARGEFILE, 0); | |
1496 | error = PTR_ERR(swap_file); | |
1497 | if (IS_ERR(swap_file)) { | |
1498 | swap_file = NULL; | |
1499 | goto bad_swap_2; | |
1500 | } | |
1501 | ||
1502 | p->swap_file = swap_file; | |
1503 | mapping = swap_file->f_mapping; | |
1504 | inode = mapping->host; | |
1505 | ||
1506 | error = -EBUSY; | |
1507 | for (i = 0; i < nr_swapfiles; i++) { | |
1508 | struct swap_info_struct *q = &swap_info[i]; | |
1509 | ||
1510 | if (i == type || !q->swap_file) | |
1511 | continue; | |
1512 | if (mapping == q->swap_file->f_mapping) | |
1513 | goto bad_swap; | |
1514 | } | |
1515 | ||
1516 | error = -EINVAL; | |
1517 | if (S_ISBLK(inode->i_mode)) { | |
1518 | bdev = I_BDEV(inode); | |
1519 | error = bd_claim(bdev, sys_swapon); | |
1520 | if (error < 0) { | |
1521 | bdev = NULL; | |
f7b3a435 | 1522 | error = -EINVAL; |
1da177e4 LT |
1523 | goto bad_swap; |
1524 | } | |
1525 | p->old_block_size = block_size(bdev); | |
1526 | error = set_blocksize(bdev, PAGE_SIZE); | |
1527 | if (error < 0) | |
1528 | goto bad_swap; | |
1529 | p->bdev = bdev; | |
1530 | } else if (S_ISREG(inode->i_mode)) { | |
1531 | p->bdev = inode->i_sb->s_bdev; | |
1b1dcc1b | 1532 | mutex_lock(&inode->i_mutex); |
1da177e4 LT |
1533 | did_down = 1; |
1534 | if (IS_SWAPFILE(inode)) { | |
1535 | error = -EBUSY; | |
1536 | goto bad_swap; | |
1537 | } | |
1538 | } else { | |
1539 | goto bad_swap; | |
1540 | } | |
1541 | ||
73fd8748 | 1542 | swapfilepages = i_size_read(inode) >> PAGE_SHIFT; |
1da177e4 LT |
1543 | |
1544 | /* | |
1545 | * Read the swap header. | |
1546 | */ | |
1547 | if (!mapping->a_ops->readpage) { | |
1548 | error = -EINVAL; | |
1549 | goto bad_swap; | |
1550 | } | |
090d2b18 | 1551 | page = read_mapping_page(mapping, 0, swap_file); |
1da177e4 LT |
1552 | if (IS_ERR(page)) { |
1553 | error = PTR_ERR(page); | |
1554 | goto bad_swap; | |
1555 | } | |
1da177e4 LT |
1556 | kmap(page); |
1557 | swap_header = page_address(page); | |
1558 | ||
1559 | if (!memcmp("SWAP-SPACE",swap_header->magic.magic,10)) | |
1560 | swap_header_version = 1; | |
1561 | else if (!memcmp("SWAPSPACE2",swap_header->magic.magic,10)) | |
1562 | swap_header_version = 2; | |
1563 | else { | |
e97a3111 | 1564 | printk(KERN_ERR "Unable to find swap-space signature\n"); |
1da177e4 LT |
1565 | error = -EINVAL; |
1566 | goto bad_swap; | |
1567 | } | |
1568 | ||
1569 | switch (swap_header_version) { | |
1570 | case 1: | |
1571 | printk(KERN_ERR "version 0 swap is no longer supported. " | |
1572 | "Use mkswap -v1 %s\n", name); | |
1573 | error = -EINVAL; | |
1574 | goto bad_swap; | |
1575 | case 2: | |
797df574 CD |
1576 | /* swap partition endianess hack... */ |
1577 | if (swab32(swap_header->info.version) == 1) { | |
1578 | swab32s(&swap_header->info.version); | |
1579 | swab32s(&swap_header->info.last_page); | |
1580 | swab32s(&swap_header->info.nr_badpages); | |
1581 | for (i = 0; i < swap_header->info.nr_badpages; i++) | |
1582 | swab32s(&swap_header->info.badpages[i]); | |
1583 | } | |
1da177e4 LT |
1584 | /* Check the swap header's sub-version and the size of |
1585 | the swap file and bad block lists */ | |
1586 | if (swap_header->info.version != 1) { | |
1587 | printk(KERN_WARNING | |
1588 | "Unable to handle swap header version %d\n", | |
1589 | swap_header->info.version); | |
1590 | error = -EINVAL; | |
1591 | goto bad_swap; | |
1592 | } | |
1593 | ||
1594 | p->lowest_bit = 1; | |
52b7efdb HD |
1595 | p->cluster_next = 1; |
1596 | ||
1da177e4 LT |
1597 | /* |
1598 | * Find out how many pages are allowed for a single swap | |
1599 | * device. There are two limiting factors: 1) the number of | |
1600 | * bits for the swap offset in the swp_entry_t type and | |
1601 | * 2) the number of bits in the a swap pte as defined by | |
1602 | * the different architectures. In order to find the | |
1603 | * largest possible bit mask a swap entry with swap type 0 | |
1604 | * and swap offset ~0UL is created, encoded to a swap pte, | |
1605 | * decoded to a swp_entry_t again and finally the swap | |
1606 | * offset is extracted. This will mask all the bits from | |
1607 | * the initial ~0UL mask that can't be encoded in either | |
1608 | * the swp_entry_t or the architecture definition of a | |
1609 | * swap pte. | |
1610 | */ | |
1611 | maxpages = swp_offset(pte_to_swp_entry(swp_entry_to_pte(swp_entry(0,~0UL)))) - 1; | |
1612 | if (maxpages > swap_header->info.last_page) | |
1613 | maxpages = swap_header->info.last_page; | |
1614 | p->highest_bit = maxpages - 1; | |
1615 | ||
1616 | error = -EINVAL; | |
e2244ec2 HD |
1617 | if (!maxpages) |
1618 | goto bad_swap; | |
73fd8748 | 1619 | if (swapfilepages && maxpages > swapfilepages) { |
5d1854e1 ES |
1620 | printk(KERN_WARNING |
1621 | "Swap area shorter than signature indicates\n"); | |
1622 | goto bad_swap; | |
1623 | } | |
e2244ec2 HD |
1624 | if (swap_header->info.nr_badpages && S_ISREG(inode->i_mode)) |
1625 | goto bad_swap; | |
1da177e4 LT |
1626 | if (swap_header->info.nr_badpages > MAX_SWAP_BADPAGES) |
1627 | goto bad_swap; | |
cd105df4 | 1628 | |
1da177e4 | 1629 | /* OK, set up the swap map and apply the bad block list */ |
78ecba08 HD |
1630 | swap_map = vmalloc(maxpages * sizeof(short)); |
1631 | if (!swap_map) { | |
1da177e4 LT |
1632 | error = -ENOMEM; |
1633 | goto bad_swap; | |
1634 | } | |
1635 | ||
1636 | error = 0; | |
78ecba08 | 1637 | memset(swap_map, 0, maxpages * sizeof(short)); |
cd105df4 TK |
1638 | for (i = 0; i < swap_header->info.nr_badpages; i++) { |
1639 | int page_nr = swap_header->info.badpages[i]; | |
1640 | if (page_nr <= 0 || page_nr >= swap_header->info.last_page) | |
1da177e4 LT |
1641 | error = -EINVAL; |
1642 | else | |
78ecba08 | 1643 | swap_map[page_nr] = SWAP_MAP_BAD; |
1da177e4 LT |
1644 | } |
1645 | nr_good_pages = swap_header->info.last_page - | |
1646 | swap_header->info.nr_badpages - | |
1647 | 1 /* header page */; | |
cd105df4 | 1648 | if (error) |
1da177e4 LT |
1649 | goto bad_swap; |
1650 | } | |
e2244ec2 | 1651 | |
e2244ec2 | 1652 | if (nr_good_pages) { |
78ecba08 | 1653 | swap_map[0] = SWAP_MAP_BAD; |
e2244ec2 HD |
1654 | p->max = maxpages; |
1655 | p->pages = nr_good_pages; | |
53092a74 HD |
1656 | nr_extents = setup_swap_extents(p, &span); |
1657 | if (nr_extents < 0) { | |
1658 | error = nr_extents; | |
e2244ec2 | 1659 | goto bad_swap; |
53092a74 | 1660 | } |
e2244ec2 HD |
1661 | nr_good_pages = p->pages; |
1662 | } | |
1da177e4 LT |
1663 | if (!nr_good_pages) { |
1664 | printk(KERN_WARNING "Empty swap-file\n"); | |
1665 | error = -EINVAL; | |
1666 | goto bad_swap; | |
1667 | } | |
1da177e4 | 1668 | |
fc0abb14 | 1669 | mutex_lock(&swapon_mutex); |
5d337b91 | 1670 | spin_lock(&swap_lock); |
78ecba08 HD |
1671 | if (swap_flags & SWAP_FLAG_PREFER) |
1672 | p->prio = | |
1673 | (swap_flags & SWAP_FLAG_PRIO_MASK) >> SWAP_FLAG_PRIO_SHIFT; | |
1674 | else | |
1675 | p->prio = --least_priority; | |
1676 | p->swap_map = swap_map; | |
1da177e4 LT |
1677 | p->flags = SWP_ACTIVE; |
1678 | nr_swap_pages += nr_good_pages; | |
1679 | total_swap_pages += nr_good_pages; | |
53092a74 | 1680 | |
6eb396dc | 1681 | printk(KERN_INFO "Adding %uk swap on %s. " |
53092a74 HD |
1682 | "Priority:%d extents:%d across:%lluk\n", |
1683 | nr_good_pages<<(PAGE_SHIFT-10), name, p->prio, | |
1684 | nr_extents, (unsigned long long)span<<(PAGE_SHIFT-10)); | |
1da177e4 LT |
1685 | |
1686 | /* insert swap space into swap_list: */ | |
1687 | prev = -1; | |
1688 | for (i = swap_list.head; i >= 0; i = swap_info[i].next) { | |
1689 | if (p->prio >= swap_info[i].prio) { | |
1690 | break; | |
1691 | } | |
1692 | prev = i; | |
1693 | } | |
1694 | p->next = i; | |
1695 | if (prev < 0) { | |
1696 | swap_list.head = swap_list.next = p - swap_info; | |
1697 | } else { | |
1698 | swap_info[prev].next = p - swap_info; | |
1699 | } | |
5d337b91 | 1700 | spin_unlock(&swap_lock); |
fc0abb14 | 1701 | mutex_unlock(&swapon_mutex); |
1da177e4 LT |
1702 | error = 0; |
1703 | goto out; | |
1704 | bad_swap: | |
1705 | if (bdev) { | |
1706 | set_blocksize(bdev, p->old_block_size); | |
1707 | bd_release(bdev); | |
1708 | } | |
4cd3bb10 | 1709 | destroy_swap_extents(p); |
1da177e4 | 1710 | bad_swap_2: |
5d337b91 | 1711 | spin_lock(&swap_lock); |
1da177e4 | 1712 | p->swap_file = NULL; |
1da177e4 | 1713 | p->flags = 0; |
5d337b91 | 1714 | spin_unlock(&swap_lock); |
1da177e4 LT |
1715 | vfree(swap_map); |
1716 | if (swap_file) | |
1717 | filp_close(swap_file, NULL); | |
1718 | out: | |
1719 | if (page && !IS_ERR(page)) { | |
1720 | kunmap(page); | |
1721 | page_cache_release(page); | |
1722 | } | |
1723 | if (name) | |
1724 | putname(name); | |
1725 | if (did_down) { | |
1726 | if (!error) | |
1727 | inode->i_flags |= S_SWAPFILE; | |
1b1dcc1b | 1728 | mutex_unlock(&inode->i_mutex); |
1da177e4 LT |
1729 | } |
1730 | return error; | |
1731 | } | |
1732 | ||
1733 | void si_swapinfo(struct sysinfo *val) | |
1734 | { | |
1735 | unsigned int i; | |
1736 | unsigned long nr_to_be_unused = 0; | |
1737 | ||
5d337b91 | 1738 | spin_lock(&swap_lock); |
1da177e4 LT |
1739 | for (i = 0; i < nr_swapfiles; i++) { |
1740 | if (!(swap_info[i].flags & SWP_USED) || | |
1741 | (swap_info[i].flags & SWP_WRITEOK)) | |
1742 | continue; | |
1743 | nr_to_be_unused += swap_info[i].inuse_pages; | |
1744 | } | |
1745 | val->freeswap = nr_swap_pages + nr_to_be_unused; | |
1746 | val->totalswap = total_swap_pages + nr_to_be_unused; | |
5d337b91 | 1747 | spin_unlock(&swap_lock); |
1da177e4 LT |
1748 | } |
1749 | ||
1750 | /* | |
1751 | * Verify that a swap entry is valid and increment its swap map count. | |
1752 | * | |
1753 | * Note: if swap_map[] reaches SWAP_MAP_MAX the entries are treated as | |
1754 | * "permanent", but will be reclaimed by the next swapoff. | |
1755 | */ | |
1756 | int swap_duplicate(swp_entry_t entry) | |
1757 | { | |
1758 | struct swap_info_struct * p; | |
1759 | unsigned long offset, type; | |
1760 | int result = 0; | |
1761 | ||
0697212a CL |
1762 | if (is_migration_entry(entry)) |
1763 | return 1; | |
1764 | ||
1da177e4 LT |
1765 | type = swp_type(entry); |
1766 | if (type >= nr_swapfiles) | |
1767 | goto bad_file; | |
1768 | p = type + swap_info; | |
1769 | offset = swp_offset(entry); | |
1770 | ||
5d337b91 | 1771 | spin_lock(&swap_lock); |
1da177e4 LT |
1772 | if (offset < p->max && p->swap_map[offset]) { |
1773 | if (p->swap_map[offset] < SWAP_MAP_MAX - 1) { | |
1774 | p->swap_map[offset]++; | |
1775 | result = 1; | |
1776 | } else if (p->swap_map[offset] <= SWAP_MAP_MAX) { | |
1777 | if (swap_overflow++ < 5) | |
1778 | printk(KERN_WARNING "swap_dup: swap entry overflow\n"); | |
1779 | p->swap_map[offset] = SWAP_MAP_MAX; | |
1780 | result = 1; | |
1781 | } | |
1782 | } | |
5d337b91 | 1783 | spin_unlock(&swap_lock); |
1da177e4 LT |
1784 | out: |
1785 | return result; | |
1786 | ||
1787 | bad_file: | |
1788 | printk(KERN_ERR "swap_dup: %s%08lx\n", Bad_file, entry.val); | |
1789 | goto out; | |
1790 | } | |
1791 | ||
1792 | struct swap_info_struct * | |
1793 | get_swap_info_struct(unsigned type) | |
1794 | { | |
1795 | return &swap_info[type]; | |
1796 | } | |
1797 | ||
1798 | /* | |
5d337b91 | 1799 | * swap_lock prevents swap_map being freed. Don't grab an extra |
1da177e4 LT |
1800 | * reference on the swaphandle, it doesn't matter if it becomes unused. |
1801 | */ | |
1802 | int valid_swaphandles(swp_entry_t entry, unsigned long *offset) | |
1803 | { | |
8952898b | 1804 | struct swap_info_struct *si; |
3f9e7949 | 1805 | int our_page_cluster = page_cluster; |
8952898b HD |
1806 | pgoff_t target, toff; |
1807 | pgoff_t base, end; | |
1808 | int nr_pages = 0; | |
1da177e4 | 1809 | |
3f9e7949 | 1810 | if (!our_page_cluster) /* no readahead */ |
1da177e4 | 1811 | return 0; |
8952898b HD |
1812 | |
1813 | si = &swap_info[swp_type(entry)]; | |
1814 | target = swp_offset(entry); | |
1815 | base = (target >> our_page_cluster) << our_page_cluster; | |
1816 | end = base + (1 << our_page_cluster); | |
1817 | if (!base) /* first page is swap header */ | |
1818 | base++; | |
1da177e4 | 1819 | |
5d337b91 | 1820 | spin_lock(&swap_lock); |
8952898b HD |
1821 | if (end > si->max) /* don't go beyond end of map */ |
1822 | end = si->max; | |
1823 | ||
1824 | /* Count contiguous allocated slots above our target */ | |
1825 | for (toff = target; ++toff < end; nr_pages++) { | |
1826 | /* Don't read in free or bad pages */ | |
1827 | if (!si->swap_map[toff]) | |
1828 | break; | |
1829 | if (si->swap_map[toff] == SWAP_MAP_BAD) | |
1da177e4 | 1830 | break; |
8952898b HD |
1831 | } |
1832 | /* Count contiguous allocated slots below our target */ | |
1833 | for (toff = target; --toff >= base; nr_pages++) { | |
1da177e4 | 1834 | /* Don't read in free or bad pages */ |
8952898b | 1835 | if (!si->swap_map[toff]) |
1da177e4 | 1836 | break; |
8952898b | 1837 | if (si->swap_map[toff] == SWAP_MAP_BAD) |
1da177e4 | 1838 | break; |
8952898b | 1839 | } |
5d337b91 | 1840 | spin_unlock(&swap_lock); |
8952898b HD |
1841 | |
1842 | /* | |
1843 | * Indicate starting offset, and return number of pages to get: | |
1844 | * if only 1, say 0, since there's then no readahead to be done. | |
1845 | */ | |
1846 | *offset = ++toff; | |
1847 | return nr_pages? ++nr_pages: 0; | |
1da177e4 | 1848 | } |