Commit | Line | Data |
---|---|---|
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> | |
20137a49 | 19 | #include <linux/random.h> |
1da177e4 LT |
20 | #include <linux/writeback.h> |
21 | #include <linux/proc_fs.h> | |
22 | #include <linux/seq_file.h> | |
23 | #include <linux/init.h> | |
24 | #include <linux/module.h> | |
5ad64688 | 25 | #include <linux/ksm.h> |
1da177e4 LT |
26 | #include <linux/rmap.h> |
27 | #include <linux/security.h> | |
28 | #include <linux/backing-dev.h> | |
fc0abb14 | 29 | #include <linux/mutex.h> |
c59ede7b | 30 | #include <linux/capability.h> |
1da177e4 | 31 | #include <linux/syscalls.h> |
8a9f3ccd | 32 | #include <linux/memcontrol.h> |
66d7dd51 | 33 | #include <linux/poll.h> |
1da177e4 LT |
34 | |
35 | #include <asm/pgtable.h> | |
36 | #include <asm/tlbflush.h> | |
37 | #include <linux/swapops.h> | |
27a7faa0 | 38 | #include <linux/page_cgroup.h> |
1da177e4 | 39 | |
570a335b HD |
40 | static bool swap_count_continued(struct swap_info_struct *, pgoff_t, |
41 | unsigned char); | |
42 | static void free_swap_count_continuations(struct swap_info_struct *); | |
d4906e1a | 43 | static sector_t map_swap_entry(swp_entry_t, struct block_device**); |
570a335b | 44 | |
7c363b8c AB |
45 | static DEFINE_SPINLOCK(swap_lock); |
46 | static unsigned int nr_swapfiles; | |
b962716b | 47 | long nr_swap_pages; |
1da177e4 | 48 | long total_swap_pages; |
78ecba08 | 49 | static int least_priority; |
1da177e4 | 50 | |
1da177e4 LT |
51 | static const char Bad_file[] = "Bad swap file entry "; |
52 | static const char Unused_file[] = "Unused swap file entry "; | |
53 | static const char Bad_offset[] = "Bad swap offset entry "; | |
54 | static const char Unused_offset[] = "Unused swap offset entry "; | |
55 | ||
7c363b8c | 56 | static struct swap_list_t swap_list = {-1, -1}; |
1da177e4 | 57 | |
efa90a98 | 58 | static struct swap_info_struct *swap_info[MAX_SWAPFILES]; |
1da177e4 | 59 | |
fc0abb14 | 60 | static DEFINE_MUTEX(swapon_mutex); |
1da177e4 | 61 | |
66d7dd51 KS |
62 | static DECLARE_WAIT_QUEUE_HEAD(proc_poll_wait); |
63 | /* Activity counter to indicate that a swapon or swapoff has occurred */ | |
64 | static atomic_t proc_poll_event = ATOMIC_INIT(0); | |
65 | ||
8d69aaee | 66 | static inline unsigned char swap_count(unsigned char ent) |
355cfa73 | 67 | { |
570a335b | 68 | return ent & ~SWAP_HAS_CACHE; /* may include SWAP_HAS_CONT flag */ |
355cfa73 KH |
69 | } |
70 | ||
efa90a98 | 71 | /* returns 1 if swap entry is freed */ |
c9e44410 KH |
72 | static int |
73 | __try_to_reclaim_swap(struct swap_info_struct *si, unsigned long offset) | |
74 | { | |
efa90a98 | 75 | swp_entry_t entry = swp_entry(si->type, offset); |
c9e44410 KH |
76 | struct page *page; |
77 | int ret = 0; | |
78 | ||
79 | page = find_get_page(&swapper_space, entry.val); | |
80 | if (!page) | |
81 | return 0; | |
82 | /* | |
83 | * This function is called from scan_swap_map() and it's called | |
84 | * by vmscan.c at reclaiming pages. So, we hold a lock on a page, here. | |
85 | * We have to use trylock for avoiding deadlock. This is a special | |
86 | * case and you should use try_to_free_swap() with explicit lock_page() | |
87 | * in usual operations. | |
88 | */ | |
89 | if (trylock_page(page)) { | |
90 | ret = try_to_free_swap(page); | |
91 | unlock_page(page); | |
92 | } | |
93 | page_cache_release(page); | |
94 | return ret; | |
95 | } | |
355cfa73 | 96 | |
1da177e4 LT |
97 | /* |
98 | * We need this because the bdev->unplug_fn can sleep and we cannot | |
5d337b91 | 99 | * hold swap_lock while calling the unplug_fn. And swap_lock |
fc0abb14 | 100 | * cannot be turned into a mutex. |
1da177e4 LT |
101 | */ |
102 | static DECLARE_RWSEM(swap_unplug_sem); | |
103 | ||
1da177e4 LT |
104 | void swap_unplug_io_fn(struct backing_dev_info *unused_bdi, struct page *page) |
105 | { | |
106 | swp_entry_t entry; | |
107 | ||
108 | down_read(&swap_unplug_sem); | |
4c21e2f2 | 109 | entry.val = page_private(page); |
1da177e4 | 110 | if (PageSwapCache(page)) { |
efa90a98 | 111 | struct block_device *bdev = swap_info[swp_type(entry)]->bdev; |
1da177e4 LT |
112 | struct backing_dev_info *bdi; |
113 | ||
114 | /* | |
115 | * If the page is removed from swapcache from under us (with a | |
116 | * racy try_to_unuse/swapoff) we need an additional reference | |
4c21e2f2 HD |
117 | * count to avoid reading garbage from page_private(page) above. |
118 | * If the WARN_ON triggers during a swapoff it maybe the race | |
1da177e4 LT |
119 | * condition and it's harmless. However if it triggers without |
120 | * swapoff it signals a problem. | |
121 | */ | |
122 | WARN_ON(page_count(page) <= 1); | |
123 | ||
124 | bdi = bdev->bd_inode->i_mapping->backing_dev_info; | |
ba32311e | 125 | blk_run_backing_dev(bdi, page); |
1da177e4 LT |
126 | } |
127 | up_read(&swap_unplug_sem); | |
128 | } | |
129 | ||
6a6ba831 HD |
130 | /* |
131 | * swapon tell device that all the old swap contents can be discarded, | |
132 | * to allow the swap device to optimize its wear-levelling. | |
133 | */ | |
134 | static int discard_swap(struct swap_info_struct *si) | |
135 | { | |
136 | struct swap_extent *se; | |
9625a5f2 HD |
137 | sector_t start_block; |
138 | sector_t nr_blocks; | |
6a6ba831 HD |
139 | int err = 0; |
140 | ||
9625a5f2 HD |
141 | /* Do not discard the swap header page! */ |
142 | se = &si->first_swap_extent; | |
143 | start_block = (se->start_block + 1) << (PAGE_SHIFT - 9); | |
144 | nr_blocks = ((sector_t)se->nr_pages - 1) << (PAGE_SHIFT - 9); | |
145 | if (nr_blocks) { | |
146 | err = blkdev_issue_discard(si->bdev, start_block, | |
dd3932ed | 147 | nr_blocks, GFP_KERNEL, 0); |
9625a5f2 HD |
148 | if (err) |
149 | return err; | |
150 | cond_resched(); | |
151 | } | |
6a6ba831 | 152 | |
9625a5f2 HD |
153 | list_for_each_entry(se, &si->first_swap_extent.list, list) { |
154 | start_block = se->start_block << (PAGE_SHIFT - 9); | |
155 | nr_blocks = (sector_t)se->nr_pages << (PAGE_SHIFT - 9); | |
6a6ba831 HD |
156 | |
157 | err = blkdev_issue_discard(si->bdev, start_block, | |
dd3932ed | 158 | nr_blocks, GFP_KERNEL, 0); |
6a6ba831 HD |
159 | if (err) |
160 | break; | |
161 | ||
162 | cond_resched(); | |
163 | } | |
164 | return err; /* That will often be -EOPNOTSUPP */ | |
165 | } | |
166 | ||
7992fde7 HD |
167 | /* |
168 | * swap allocation tell device that a cluster of swap can now be discarded, | |
169 | * to allow the swap device to optimize its wear-levelling. | |
170 | */ | |
171 | static void discard_swap_cluster(struct swap_info_struct *si, | |
172 | pgoff_t start_page, pgoff_t nr_pages) | |
173 | { | |
174 | struct swap_extent *se = si->curr_swap_extent; | |
175 | int found_extent = 0; | |
176 | ||
177 | while (nr_pages) { | |
178 | struct list_head *lh; | |
179 | ||
180 | if (se->start_page <= start_page && | |
181 | start_page < se->start_page + se->nr_pages) { | |
182 | pgoff_t offset = start_page - se->start_page; | |
183 | sector_t start_block = se->start_block + offset; | |
858a2990 | 184 | sector_t nr_blocks = se->nr_pages - offset; |
7992fde7 HD |
185 | |
186 | if (nr_blocks > nr_pages) | |
187 | nr_blocks = nr_pages; | |
188 | start_page += nr_blocks; | |
189 | nr_pages -= nr_blocks; | |
190 | ||
191 | if (!found_extent++) | |
192 | si->curr_swap_extent = se; | |
193 | ||
194 | start_block <<= PAGE_SHIFT - 9; | |
195 | nr_blocks <<= PAGE_SHIFT - 9; | |
196 | if (blkdev_issue_discard(si->bdev, start_block, | |
dd3932ed | 197 | nr_blocks, GFP_NOIO, 0)) |
7992fde7 HD |
198 | break; |
199 | } | |
200 | ||
201 | lh = se->list.next; | |
7992fde7 HD |
202 | se = list_entry(lh, struct swap_extent, list); |
203 | } | |
204 | } | |
205 | ||
206 | static int wait_for_discard(void *word) | |
207 | { | |
208 | schedule(); | |
209 | return 0; | |
210 | } | |
211 | ||
048c27fd HD |
212 | #define SWAPFILE_CLUSTER 256 |
213 | #define LATENCY_LIMIT 256 | |
214 | ||
355cfa73 | 215 | static inline unsigned long scan_swap_map(struct swap_info_struct *si, |
8d69aaee | 216 | unsigned char usage) |
1da177e4 | 217 | { |
ebebbbe9 | 218 | unsigned long offset; |
c60aa176 | 219 | unsigned long scan_base; |
7992fde7 | 220 | unsigned long last_in_cluster = 0; |
048c27fd | 221 | int latency_ration = LATENCY_LIMIT; |
7992fde7 | 222 | int found_free_cluster = 0; |
7dfad418 | 223 | |
886bb7e9 | 224 | /* |
7dfad418 HD |
225 | * We try to cluster swap pages by allocating them sequentially |
226 | * in swap. Once we've allocated SWAPFILE_CLUSTER pages this | |
227 | * way, however, we resort to first-free allocation, starting | |
228 | * a new cluster. This prevents us from scattering swap pages | |
229 | * all over the entire swap partition, so that we reduce | |
230 | * overall disk seek times between swap pages. -- sct | |
231 | * But we do now try to find an empty cluster. -Andrea | |
c60aa176 | 232 | * And we let swap pages go all over an SSD partition. Hugh |
7dfad418 HD |
233 | */ |
234 | ||
52b7efdb | 235 | si->flags += SWP_SCANNING; |
c60aa176 | 236 | scan_base = offset = si->cluster_next; |
ebebbbe9 HD |
237 | |
238 | if (unlikely(!si->cluster_nr--)) { | |
239 | if (si->pages - si->inuse_pages < SWAPFILE_CLUSTER) { | |
240 | si->cluster_nr = SWAPFILE_CLUSTER - 1; | |
241 | goto checks; | |
242 | } | |
7992fde7 HD |
243 | if (si->flags & SWP_DISCARDABLE) { |
244 | /* | |
245 | * Start range check on racing allocations, in case | |
246 | * they overlap the cluster we eventually decide on | |
247 | * (we scan without swap_lock to allow preemption). | |
248 | * It's hardly conceivable that cluster_nr could be | |
249 | * wrapped during our scan, but don't depend on it. | |
250 | */ | |
251 | if (si->lowest_alloc) | |
252 | goto checks; | |
253 | si->lowest_alloc = si->max; | |
254 | si->highest_alloc = 0; | |
255 | } | |
5d337b91 | 256 | spin_unlock(&swap_lock); |
7dfad418 | 257 | |
c60aa176 HD |
258 | /* |
259 | * If seek is expensive, start searching for new cluster from | |
260 | * start of partition, to minimize the span of allocated swap. | |
261 | * But if seek is cheap, search from our current position, so | |
262 | * that swap is allocated from all over the partition: if the | |
263 | * Flash Translation Layer only remaps within limited zones, | |
264 | * we don't want to wear out the first zone too quickly. | |
265 | */ | |
266 | if (!(si->flags & SWP_SOLIDSTATE)) | |
267 | scan_base = offset = si->lowest_bit; | |
7dfad418 HD |
268 | last_in_cluster = offset + SWAPFILE_CLUSTER - 1; |
269 | ||
270 | /* Locate the first empty (unaligned) cluster */ | |
271 | for (; last_in_cluster <= si->highest_bit; offset++) { | |
1da177e4 | 272 | if (si->swap_map[offset]) |
7dfad418 HD |
273 | last_in_cluster = offset + SWAPFILE_CLUSTER; |
274 | else if (offset == last_in_cluster) { | |
5d337b91 | 275 | spin_lock(&swap_lock); |
ebebbbe9 HD |
276 | offset -= SWAPFILE_CLUSTER - 1; |
277 | si->cluster_next = offset; | |
278 | si->cluster_nr = SWAPFILE_CLUSTER - 1; | |
7992fde7 | 279 | found_free_cluster = 1; |
ebebbbe9 | 280 | goto checks; |
1da177e4 | 281 | } |
048c27fd HD |
282 | if (unlikely(--latency_ration < 0)) { |
283 | cond_resched(); | |
284 | latency_ration = LATENCY_LIMIT; | |
285 | } | |
7dfad418 | 286 | } |
ebebbbe9 HD |
287 | |
288 | offset = si->lowest_bit; | |
c60aa176 HD |
289 | last_in_cluster = offset + SWAPFILE_CLUSTER - 1; |
290 | ||
291 | /* Locate the first empty (unaligned) cluster */ | |
292 | for (; last_in_cluster < scan_base; offset++) { | |
293 | if (si->swap_map[offset]) | |
294 | last_in_cluster = offset + SWAPFILE_CLUSTER; | |
295 | else if (offset == last_in_cluster) { | |
296 | spin_lock(&swap_lock); | |
297 | offset -= SWAPFILE_CLUSTER - 1; | |
298 | si->cluster_next = offset; | |
299 | si->cluster_nr = SWAPFILE_CLUSTER - 1; | |
300 | found_free_cluster = 1; | |
301 | goto checks; | |
302 | } | |
303 | if (unlikely(--latency_ration < 0)) { | |
304 | cond_resched(); | |
305 | latency_ration = LATENCY_LIMIT; | |
306 | } | |
307 | } | |
308 | ||
309 | offset = scan_base; | |
5d337b91 | 310 | spin_lock(&swap_lock); |
ebebbbe9 | 311 | si->cluster_nr = SWAPFILE_CLUSTER - 1; |
7992fde7 | 312 | si->lowest_alloc = 0; |
1da177e4 | 313 | } |
7dfad418 | 314 | |
ebebbbe9 HD |
315 | checks: |
316 | if (!(si->flags & SWP_WRITEOK)) | |
52b7efdb | 317 | goto no_page; |
7dfad418 HD |
318 | if (!si->highest_bit) |
319 | goto no_page; | |
ebebbbe9 | 320 | if (offset > si->highest_bit) |
c60aa176 | 321 | scan_base = offset = si->lowest_bit; |
c9e44410 | 322 | |
b73d7fce HD |
323 | /* reuse swap entry of cache-only swap if not busy. */ |
324 | if (vm_swap_full() && si->swap_map[offset] == SWAP_HAS_CACHE) { | |
c9e44410 KH |
325 | int swap_was_freed; |
326 | spin_unlock(&swap_lock); | |
327 | swap_was_freed = __try_to_reclaim_swap(si, offset); | |
328 | spin_lock(&swap_lock); | |
329 | /* entry was freed successfully, try to use this again */ | |
330 | if (swap_was_freed) | |
331 | goto checks; | |
332 | goto scan; /* check next one */ | |
333 | } | |
334 | ||
ebebbbe9 HD |
335 | if (si->swap_map[offset]) |
336 | goto scan; | |
337 | ||
338 | if (offset == si->lowest_bit) | |
339 | si->lowest_bit++; | |
340 | if (offset == si->highest_bit) | |
341 | si->highest_bit--; | |
342 | si->inuse_pages++; | |
343 | if (si->inuse_pages == si->pages) { | |
344 | si->lowest_bit = si->max; | |
345 | si->highest_bit = 0; | |
1da177e4 | 346 | } |
253d553b | 347 | si->swap_map[offset] = usage; |
ebebbbe9 HD |
348 | si->cluster_next = offset + 1; |
349 | si->flags -= SWP_SCANNING; | |
7992fde7 HD |
350 | |
351 | if (si->lowest_alloc) { | |
352 | /* | |
353 | * Only set when SWP_DISCARDABLE, and there's a scan | |
354 | * for a free cluster in progress or just completed. | |
355 | */ | |
356 | if (found_free_cluster) { | |
357 | /* | |
358 | * To optimize wear-levelling, discard the | |
359 | * old data of the cluster, taking care not to | |
360 | * discard any of its pages that have already | |
361 | * been allocated by racing tasks (offset has | |
362 | * already stepped over any at the beginning). | |
363 | */ | |
364 | if (offset < si->highest_alloc && | |
365 | si->lowest_alloc <= last_in_cluster) | |
366 | last_in_cluster = si->lowest_alloc - 1; | |
367 | si->flags |= SWP_DISCARDING; | |
368 | spin_unlock(&swap_lock); | |
369 | ||
370 | if (offset < last_in_cluster) | |
371 | discard_swap_cluster(si, offset, | |
372 | last_in_cluster - offset + 1); | |
373 | ||
374 | spin_lock(&swap_lock); | |
375 | si->lowest_alloc = 0; | |
376 | si->flags &= ~SWP_DISCARDING; | |
377 | ||
378 | smp_mb(); /* wake_up_bit advises this */ | |
379 | wake_up_bit(&si->flags, ilog2(SWP_DISCARDING)); | |
380 | ||
381 | } else if (si->flags & SWP_DISCARDING) { | |
382 | /* | |
383 | * Delay using pages allocated by racing tasks | |
384 | * until the whole discard has been issued. We | |
385 | * could defer that delay until swap_writepage, | |
386 | * but it's easier to keep this self-contained. | |
387 | */ | |
388 | spin_unlock(&swap_lock); | |
389 | wait_on_bit(&si->flags, ilog2(SWP_DISCARDING), | |
390 | wait_for_discard, TASK_UNINTERRUPTIBLE); | |
391 | spin_lock(&swap_lock); | |
392 | } else { | |
393 | /* | |
394 | * Note pages allocated by racing tasks while | |
395 | * scan for a free cluster is in progress, so | |
396 | * that its final discard can exclude them. | |
397 | */ | |
398 | if (offset < si->lowest_alloc) | |
399 | si->lowest_alloc = offset; | |
400 | if (offset > si->highest_alloc) | |
401 | si->highest_alloc = offset; | |
402 | } | |
403 | } | |
ebebbbe9 | 404 | return offset; |
7dfad418 | 405 | |
ebebbbe9 | 406 | scan: |
5d337b91 | 407 | spin_unlock(&swap_lock); |
7dfad418 | 408 | while (++offset <= si->highest_bit) { |
52b7efdb | 409 | if (!si->swap_map[offset]) { |
5d337b91 | 410 | spin_lock(&swap_lock); |
52b7efdb HD |
411 | goto checks; |
412 | } | |
c9e44410 KH |
413 | if (vm_swap_full() && si->swap_map[offset] == SWAP_HAS_CACHE) { |
414 | spin_lock(&swap_lock); | |
415 | goto checks; | |
416 | } | |
048c27fd HD |
417 | if (unlikely(--latency_ration < 0)) { |
418 | cond_resched(); | |
419 | latency_ration = LATENCY_LIMIT; | |
420 | } | |
7dfad418 | 421 | } |
c60aa176 HD |
422 | offset = si->lowest_bit; |
423 | while (++offset < scan_base) { | |
424 | if (!si->swap_map[offset]) { | |
425 | spin_lock(&swap_lock); | |
426 | goto checks; | |
427 | } | |
c9e44410 KH |
428 | if (vm_swap_full() && si->swap_map[offset] == SWAP_HAS_CACHE) { |
429 | spin_lock(&swap_lock); | |
430 | goto checks; | |
431 | } | |
c60aa176 HD |
432 | if (unlikely(--latency_ration < 0)) { |
433 | cond_resched(); | |
434 | latency_ration = LATENCY_LIMIT; | |
435 | } | |
436 | } | |
5d337b91 | 437 | spin_lock(&swap_lock); |
7dfad418 HD |
438 | |
439 | no_page: | |
52b7efdb | 440 | si->flags -= SWP_SCANNING; |
1da177e4 LT |
441 | return 0; |
442 | } | |
443 | ||
444 | swp_entry_t get_swap_page(void) | |
445 | { | |
fb4f88dc HD |
446 | struct swap_info_struct *si; |
447 | pgoff_t offset; | |
448 | int type, next; | |
449 | int wrapped = 0; | |
1da177e4 | 450 | |
5d337b91 | 451 | spin_lock(&swap_lock); |
1da177e4 | 452 | if (nr_swap_pages <= 0) |
fb4f88dc HD |
453 | goto noswap; |
454 | nr_swap_pages--; | |
455 | ||
456 | for (type = swap_list.next; type >= 0 && wrapped < 2; type = next) { | |
efa90a98 | 457 | si = swap_info[type]; |
fb4f88dc HD |
458 | next = si->next; |
459 | if (next < 0 || | |
efa90a98 | 460 | (!wrapped && si->prio != swap_info[next]->prio)) { |
fb4f88dc HD |
461 | next = swap_list.head; |
462 | wrapped++; | |
1da177e4 | 463 | } |
fb4f88dc HD |
464 | |
465 | if (!si->highest_bit) | |
466 | continue; | |
467 | if (!(si->flags & SWP_WRITEOK)) | |
468 | continue; | |
469 | ||
470 | swap_list.next = next; | |
355cfa73 | 471 | /* This is called for allocating swap entry for cache */ |
253d553b | 472 | offset = scan_swap_map(si, SWAP_HAS_CACHE); |
5d337b91 HD |
473 | if (offset) { |
474 | spin_unlock(&swap_lock); | |
fb4f88dc | 475 | return swp_entry(type, offset); |
5d337b91 | 476 | } |
fb4f88dc | 477 | next = swap_list.next; |
1da177e4 | 478 | } |
fb4f88dc HD |
479 | |
480 | nr_swap_pages++; | |
481 | noswap: | |
5d337b91 | 482 | spin_unlock(&swap_lock); |
fb4f88dc | 483 | return (swp_entry_t) {0}; |
1da177e4 LT |
484 | } |
485 | ||
910321ea HD |
486 | /* The only caller of this function is now susupend routine */ |
487 | swp_entry_t get_swap_page_of_type(int type) | |
488 | { | |
489 | struct swap_info_struct *si; | |
490 | pgoff_t offset; | |
491 | ||
492 | spin_lock(&swap_lock); | |
493 | si = swap_info[type]; | |
494 | if (si && (si->flags & SWP_WRITEOK)) { | |
495 | nr_swap_pages--; | |
496 | /* This is called for allocating swap entry, not cache */ | |
497 | offset = scan_swap_map(si, 1); | |
498 | if (offset) { | |
499 | spin_unlock(&swap_lock); | |
500 | return swp_entry(type, offset); | |
501 | } | |
502 | nr_swap_pages++; | |
503 | } | |
504 | spin_unlock(&swap_lock); | |
505 | return (swp_entry_t) {0}; | |
506 | } | |
507 | ||
73c34b6a | 508 | static struct swap_info_struct *swap_info_get(swp_entry_t entry) |
1da177e4 | 509 | { |
73c34b6a | 510 | struct swap_info_struct *p; |
1da177e4 LT |
511 | unsigned long offset, type; |
512 | ||
513 | if (!entry.val) | |
514 | goto out; | |
515 | type = swp_type(entry); | |
516 | if (type >= nr_swapfiles) | |
517 | goto bad_nofile; | |
efa90a98 | 518 | p = swap_info[type]; |
1da177e4 LT |
519 | if (!(p->flags & SWP_USED)) |
520 | goto bad_device; | |
521 | offset = swp_offset(entry); | |
522 | if (offset >= p->max) | |
523 | goto bad_offset; | |
524 | if (!p->swap_map[offset]) | |
525 | goto bad_free; | |
5d337b91 | 526 | spin_lock(&swap_lock); |
1da177e4 LT |
527 | return p; |
528 | ||
529 | bad_free: | |
530 | printk(KERN_ERR "swap_free: %s%08lx\n", Unused_offset, entry.val); | |
531 | goto out; | |
532 | bad_offset: | |
533 | printk(KERN_ERR "swap_free: %s%08lx\n", Bad_offset, entry.val); | |
534 | goto out; | |
535 | bad_device: | |
536 | printk(KERN_ERR "swap_free: %s%08lx\n", Unused_file, entry.val); | |
537 | goto out; | |
538 | bad_nofile: | |
539 | printk(KERN_ERR "swap_free: %s%08lx\n", Bad_file, entry.val); | |
540 | out: | |
541 | return NULL; | |
886bb7e9 | 542 | } |
1da177e4 | 543 | |
8d69aaee HD |
544 | static unsigned char swap_entry_free(struct swap_info_struct *p, |
545 | swp_entry_t entry, unsigned char usage) | |
1da177e4 | 546 | { |
253d553b | 547 | unsigned long offset = swp_offset(entry); |
8d69aaee HD |
548 | unsigned char count; |
549 | unsigned char has_cache; | |
355cfa73 | 550 | |
253d553b HD |
551 | count = p->swap_map[offset]; |
552 | has_cache = count & SWAP_HAS_CACHE; | |
553 | count &= ~SWAP_HAS_CACHE; | |
355cfa73 | 554 | |
253d553b | 555 | if (usage == SWAP_HAS_CACHE) { |
355cfa73 | 556 | VM_BUG_ON(!has_cache); |
253d553b | 557 | has_cache = 0; |
aaa46865 HD |
558 | } else if (count == SWAP_MAP_SHMEM) { |
559 | /* | |
560 | * Or we could insist on shmem.c using a special | |
561 | * swap_shmem_free() and free_shmem_swap_and_cache()... | |
562 | */ | |
563 | count = 0; | |
570a335b HD |
564 | } else if ((count & ~COUNT_CONTINUED) <= SWAP_MAP_MAX) { |
565 | if (count == COUNT_CONTINUED) { | |
566 | if (swap_count_continued(p, offset, count)) | |
567 | count = SWAP_MAP_MAX | COUNT_CONTINUED; | |
568 | else | |
569 | count = SWAP_MAP_MAX; | |
570 | } else | |
571 | count--; | |
572 | } | |
253d553b HD |
573 | |
574 | if (!count) | |
575 | mem_cgroup_uncharge_swap(entry); | |
576 | ||
577 | usage = count | has_cache; | |
578 | p->swap_map[offset] = usage; | |
355cfa73 | 579 | |
355cfa73 | 580 | /* free if no reference */ |
253d553b | 581 | if (!usage) { |
b3a27d05 | 582 | struct gendisk *disk = p->bdev->bd_disk; |
355cfa73 KH |
583 | if (offset < p->lowest_bit) |
584 | p->lowest_bit = offset; | |
585 | if (offset > p->highest_bit) | |
586 | p->highest_bit = offset; | |
efa90a98 HD |
587 | if (swap_list.next >= 0 && |
588 | p->prio > swap_info[swap_list.next]->prio) | |
589 | swap_list.next = p->type; | |
355cfa73 KH |
590 | nr_swap_pages++; |
591 | p->inuse_pages--; | |
b3a27d05 NG |
592 | if ((p->flags & SWP_BLKDEV) && |
593 | disk->fops->swap_slot_free_notify) | |
594 | disk->fops->swap_slot_free_notify(p->bdev, offset); | |
1da177e4 | 595 | } |
253d553b HD |
596 | |
597 | return usage; | |
1da177e4 LT |
598 | } |
599 | ||
600 | /* | |
601 | * Caller has made sure that the swapdevice corresponding to entry | |
602 | * is still around or has not been recycled. | |
603 | */ | |
604 | void swap_free(swp_entry_t entry) | |
605 | { | |
73c34b6a | 606 | struct swap_info_struct *p; |
1da177e4 LT |
607 | |
608 | p = swap_info_get(entry); | |
609 | if (p) { | |
253d553b | 610 | swap_entry_free(p, entry, 1); |
5d337b91 | 611 | spin_unlock(&swap_lock); |
1da177e4 LT |
612 | } |
613 | } | |
614 | ||
cb4b86ba KH |
615 | /* |
616 | * Called after dropping swapcache to decrease refcnt to swap entries. | |
617 | */ | |
618 | void swapcache_free(swp_entry_t entry, struct page *page) | |
619 | { | |
355cfa73 | 620 | struct swap_info_struct *p; |
8d69aaee | 621 | unsigned char count; |
355cfa73 | 622 | |
355cfa73 KH |
623 | p = swap_info_get(entry); |
624 | if (p) { | |
253d553b HD |
625 | count = swap_entry_free(p, entry, SWAP_HAS_CACHE); |
626 | if (page) | |
627 | mem_cgroup_uncharge_swapcache(page, entry, count != 0); | |
355cfa73 KH |
628 | spin_unlock(&swap_lock); |
629 | } | |
cb4b86ba KH |
630 | } |
631 | ||
1da177e4 | 632 | /* |
c475a8ab | 633 | * How many references to page are currently swapped out? |
570a335b HD |
634 | * This does not give an exact answer when swap count is continued, |
635 | * but does include the high COUNT_CONTINUED flag to allow for that. | |
1da177e4 | 636 | */ |
c475a8ab | 637 | static inline int page_swapcount(struct page *page) |
1da177e4 | 638 | { |
c475a8ab HD |
639 | int count = 0; |
640 | struct swap_info_struct *p; | |
1da177e4 LT |
641 | swp_entry_t entry; |
642 | ||
4c21e2f2 | 643 | entry.val = page_private(page); |
1da177e4 LT |
644 | p = swap_info_get(entry); |
645 | if (p) { | |
355cfa73 | 646 | count = swap_count(p->swap_map[swp_offset(entry)]); |
5d337b91 | 647 | spin_unlock(&swap_lock); |
1da177e4 | 648 | } |
c475a8ab | 649 | return count; |
1da177e4 LT |
650 | } |
651 | ||
652 | /* | |
7b1fe597 HD |
653 | * We can write to an anon page without COW if there are no other references |
654 | * to it. And as a side-effect, free up its swap: because the old content | |
655 | * on disk will never be read, and seeking back there to write new content | |
656 | * later would only waste time away from clustering. | |
1da177e4 | 657 | */ |
7b1fe597 | 658 | int reuse_swap_page(struct page *page) |
1da177e4 | 659 | { |
c475a8ab HD |
660 | int count; |
661 | ||
51726b12 | 662 | VM_BUG_ON(!PageLocked(page)); |
5ad64688 HD |
663 | if (unlikely(PageKsm(page))) |
664 | return 0; | |
c475a8ab | 665 | count = page_mapcount(page); |
7b1fe597 | 666 | if (count <= 1 && PageSwapCache(page)) { |
c475a8ab | 667 | count += page_swapcount(page); |
7b1fe597 HD |
668 | if (count == 1 && !PageWriteback(page)) { |
669 | delete_from_swap_cache(page); | |
670 | SetPageDirty(page); | |
671 | } | |
672 | } | |
5ad64688 | 673 | return count <= 1; |
1da177e4 LT |
674 | } |
675 | ||
676 | /* | |
a2c43eed HD |
677 | * If swap is getting full, or if there are no more mappings of this page, |
678 | * then try_to_free_swap is called to free its swap space. | |
1da177e4 | 679 | */ |
a2c43eed | 680 | int try_to_free_swap(struct page *page) |
1da177e4 | 681 | { |
51726b12 | 682 | VM_BUG_ON(!PageLocked(page)); |
1da177e4 LT |
683 | |
684 | if (!PageSwapCache(page)) | |
685 | return 0; | |
686 | if (PageWriteback(page)) | |
687 | return 0; | |
a2c43eed | 688 | if (page_swapcount(page)) |
1da177e4 LT |
689 | return 0; |
690 | ||
b73d7fce HD |
691 | /* |
692 | * Once hibernation has begun to create its image of memory, | |
693 | * there's a danger that one of the calls to try_to_free_swap() | |
694 | * - most probably a call from __try_to_reclaim_swap() while | |
695 | * hibernation is allocating its own swap pages for the image, | |
696 | * but conceivably even a call from memory reclaim - will free | |
697 | * the swap from a page which has already been recorded in the | |
698 | * image as a clean swapcache page, and then reuse its swap for | |
699 | * another page of the image. On waking from hibernation, the | |
700 | * original page might be freed under memory pressure, then | |
701 | * later read back in from swap, now with the wrong data. | |
702 | * | |
703 | * Hibernation clears bits from gfp_allowed_mask to prevent | |
704 | * memory reclaim from writing to disk, so check that here. | |
705 | */ | |
706 | if (!(gfp_allowed_mask & __GFP_IO)) | |
707 | return 0; | |
708 | ||
a2c43eed HD |
709 | delete_from_swap_cache(page); |
710 | SetPageDirty(page); | |
711 | return 1; | |
68a22394 RR |
712 | } |
713 | ||
1da177e4 LT |
714 | /* |
715 | * Free the swap entry like above, but also try to | |
716 | * free the page cache entry if it is the last user. | |
717 | */ | |
2509ef26 | 718 | int free_swap_and_cache(swp_entry_t entry) |
1da177e4 | 719 | { |
2509ef26 | 720 | struct swap_info_struct *p; |
1da177e4 LT |
721 | struct page *page = NULL; |
722 | ||
a7420aa5 | 723 | if (non_swap_entry(entry)) |
2509ef26 | 724 | return 1; |
0697212a | 725 | |
1da177e4 LT |
726 | p = swap_info_get(entry); |
727 | if (p) { | |
253d553b | 728 | if (swap_entry_free(p, entry, 1) == SWAP_HAS_CACHE) { |
93fac704 | 729 | page = find_get_page(&swapper_space, entry.val); |
8413ac9d | 730 | if (page && !trylock_page(page)) { |
93fac704 NP |
731 | page_cache_release(page); |
732 | page = NULL; | |
733 | } | |
734 | } | |
5d337b91 | 735 | spin_unlock(&swap_lock); |
1da177e4 LT |
736 | } |
737 | if (page) { | |
a2c43eed HD |
738 | /* |
739 | * Not mapped elsewhere, or swap space full? Free it! | |
740 | * Also recheck PageSwapCache now page is locked (above). | |
741 | */ | |
93fac704 | 742 | if (PageSwapCache(page) && !PageWriteback(page) && |
a2c43eed | 743 | (!page_mapped(page) || vm_swap_full())) { |
1da177e4 LT |
744 | delete_from_swap_cache(page); |
745 | SetPageDirty(page); | |
746 | } | |
747 | unlock_page(page); | |
748 | page_cache_release(page); | |
749 | } | |
2509ef26 | 750 | return p != NULL; |
1da177e4 LT |
751 | } |
752 | ||
02491447 DN |
753 | #ifdef CONFIG_CGROUP_MEM_RES_CTLR |
754 | /** | |
755 | * mem_cgroup_count_swap_user - count the user of a swap entry | |
756 | * @ent: the swap entry to be checked | |
757 | * @pagep: the pointer for the swap cache page of the entry to be stored | |
758 | * | |
759 | * Returns the number of the user of the swap entry. The number is valid only | |
760 | * for swaps of anonymous pages. | |
761 | * If the entry is found on swap cache, the page is stored to pagep with | |
762 | * refcount of it being incremented. | |
763 | */ | |
764 | int mem_cgroup_count_swap_user(swp_entry_t ent, struct page **pagep) | |
765 | { | |
766 | struct page *page; | |
767 | struct swap_info_struct *p; | |
768 | int count = 0; | |
769 | ||
770 | page = find_get_page(&swapper_space, ent.val); | |
771 | if (page) | |
772 | count += page_mapcount(page); | |
773 | p = swap_info_get(ent); | |
774 | if (p) { | |
775 | count += swap_count(p->swap_map[swp_offset(ent)]); | |
776 | spin_unlock(&swap_lock); | |
777 | } | |
778 | ||
779 | *pagep = page; | |
780 | return count; | |
781 | } | |
782 | #endif | |
783 | ||
b0cb1a19 | 784 | #ifdef CONFIG_HIBERNATION |
f577eb30 | 785 | /* |
915bae9e | 786 | * Find the swap type that corresponds to given device (if any). |
f577eb30 | 787 | * |
915bae9e RW |
788 | * @offset - number of the PAGE_SIZE-sized block of the device, starting |
789 | * from 0, in which the swap header is expected to be located. | |
790 | * | |
791 | * This is needed for the suspend to disk (aka swsusp). | |
f577eb30 | 792 | */ |
7bf23687 | 793 | int swap_type_of(dev_t device, sector_t offset, struct block_device **bdev_p) |
f577eb30 | 794 | { |
915bae9e | 795 | struct block_device *bdev = NULL; |
efa90a98 | 796 | int type; |
f577eb30 | 797 | |
915bae9e RW |
798 | if (device) |
799 | bdev = bdget(device); | |
800 | ||
f577eb30 | 801 | spin_lock(&swap_lock); |
efa90a98 HD |
802 | for (type = 0; type < nr_swapfiles; type++) { |
803 | struct swap_info_struct *sis = swap_info[type]; | |
f577eb30 | 804 | |
915bae9e | 805 | if (!(sis->flags & SWP_WRITEOK)) |
f577eb30 | 806 | continue; |
b6b5bce3 | 807 | |
915bae9e | 808 | if (!bdev) { |
7bf23687 | 809 | if (bdev_p) |
dddac6a7 | 810 | *bdev_p = bdgrab(sis->bdev); |
7bf23687 | 811 | |
6e1819d6 | 812 | spin_unlock(&swap_lock); |
efa90a98 | 813 | return type; |
6e1819d6 | 814 | } |
915bae9e | 815 | if (bdev == sis->bdev) { |
9625a5f2 | 816 | struct swap_extent *se = &sis->first_swap_extent; |
915bae9e | 817 | |
915bae9e | 818 | if (se->start_block == offset) { |
7bf23687 | 819 | if (bdev_p) |
dddac6a7 | 820 | *bdev_p = bdgrab(sis->bdev); |
7bf23687 | 821 | |
915bae9e RW |
822 | spin_unlock(&swap_lock); |
823 | bdput(bdev); | |
efa90a98 | 824 | return type; |
915bae9e | 825 | } |
f577eb30 RW |
826 | } |
827 | } | |
828 | spin_unlock(&swap_lock); | |
915bae9e RW |
829 | if (bdev) |
830 | bdput(bdev); | |
831 | ||
f577eb30 RW |
832 | return -ENODEV; |
833 | } | |
834 | ||
73c34b6a HD |
835 | /* |
836 | * Get the (PAGE_SIZE) block corresponding to given offset on the swapdev | |
837 | * corresponding to given index in swap_info (swap type). | |
838 | */ | |
839 | sector_t swapdev_block(int type, pgoff_t offset) | |
840 | { | |
841 | struct block_device *bdev; | |
842 | ||
843 | if ((unsigned int)type >= nr_swapfiles) | |
844 | return 0; | |
845 | if (!(swap_info[type]->flags & SWP_WRITEOK)) | |
846 | return 0; | |
d4906e1a | 847 | return map_swap_entry(swp_entry(type, offset), &bdev); |
73c34b6a HD |
848 | } |
849 | ||
f577eb30 RW |
850 | /* |
851 | * Return either the total number of swap pages of given type, or the number | |
852 | * of free pages of that type (depending on @free) | |
853 | * | |
854 | * This is needed for software suspend | |
855 | */ | |
856 | unsigned int count_swap_pages(int type, int free) | |
857 | { | |
858 | unsigned int n = 0; | |
859 | ||
efa90a98 HD |
860 | spin_lock(&swap_lock); |
861 | if ((unsigned int)type < nr_swapfiles) { | |
862 | struct swap_info_struct *sis = swap_info[type]; | |
863 | ||
864 | if (sis->flags & SWP_WRITEOK) { | |
865 | n = sis->pages; | |
f577eb30 | 866 | if (free) |
efa90a98 | 867 | n -= sis->inuse_pages; |
f577eb30 | 868 | } |
f577eb30 | 869 | } |
efa90a98 | 870 | spin_unlock(&swap_lock); |
f577eb30 RW |
871 | return n; |
872 | } | |
73c34b6a | 873 | #endif /* CONFIG_HIBERNATION */ |
f577eb30 | 874 | |
1da177e4 | 875 | /* |
72866f6f HD |
876 | * No need to decide whether this PTE shares the swap entry with others, |
877 | * just let do_wp_page work it out if a write is requested later - to | |
878 | * force COW, vm_page_prot omits write permission from any private vma. | |
1da177e4 | 879 | */ |
044d66c1 | 880 | static int unuse_pte(struct vm_area_struct *vma, pmd_t *pmd, |
1da177e4 LT |
881 | unsigned long addr, swp_entry_t entry, struct page *page) |
882 | { | |
7a81b88c | 883 | struct mem_cgroup *ptr = NULL; |
044d66c1 HD |
884 | spinlock_t *ptl; |
885 | pte_t *pte; | |
886 | int ret = 1; | |
887 | ||
85d9fc89 | 888 | if (mem_cgroup_try_charge_swapin(vma->vm_mm, page, GFP_KERNEL, &ptr)) { |
044d66c1 | 889 | ret = -ENOMEM; |
85d9fc89 KH |
890 | goto out_nolock; |
891 | } | |
044d66c1 HD |
892 | |
893 | pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl); | |
894 | if (unlikely(!pte_same(*pte, swp_entry_to_pte(entry)))) { | |
895 | if (ret > 0) | |
7a81b88c | 896 | mem_cgroup_cancel_charge_swapin(ptr); |
044d66c1 HD |
897 | ret = 0; |
898 | goto out; | |
899 | } | |
8a9f3ccd | 900 | |
b084d435 | 901 | dec_mm_counter(vma->vm_mm, MM_SWAPENTS); |
d559db08 | 902 | inc_mm_counter(vma->vm_mm, MM_ANONPAGES); |
1da177e4 LT |
903 | get_page(page); |
904 | set_pte_at(vma->vm_mm, addr, pte, | |
905 | pte_mkold(mk_pte(page, vma->vm_page_prot))); | |
906 | page_add_anon_rmap(page, vma, addr); | |
7a81b88c | 907 | mem_cgroup_commit_charge_swapin(page, ptr); |
1da177e4 LT |
908 | swap_free(entry); |
909 | /* | |
910 | * Move the page to the active list so it is not | |
911 | * immediately swapped out again after swapon. | |
912 | */ | |
913 | activate_page(page); | |
044d66c1 HD |
914 | out: |
915 | pte_unmap_unlock(pte, ptl); | |
85d9fc89 | 916 | out_nolock: |
044d66c1 | 917 | return ret; |
1da177e4 LT |
918 | } |
919 | ||
920 | static int unuse_pte_range(struct vm_area_struct *vma, pmd_t *pmd, | |
921 | unsigned long addr, unsigned long end, | |
922 | swp_entry_t entry, struct page *page) | |
923 | { | |
1da177e4 | 924 | pte_t swp_pte = swp_entry_to_pte(entry); |
705e87c0 | 925 | pte_t *pte; |
8a9f3ccd | 926 | int ret = 0; |
1da177e4 | 927 | |
044d66c1 HD |
928 | /* |
929 | * We don't actually need pte lock while scanning for swp_pte: since | |
930 | * we hold page lock and mmap_sem, swp_pte cannot be inserted into the | |
931 | * page table while we're scanning; though it could get zapped, and on | |
932 | * some architectures (e.g. x86_32 with PAE) we might catch a glimpse | |
933 | * of unmatched parts which look like swp_pte, so unuse_pte must | |
934 | * recheck under pte lock. Scanning without pte lock lets it be | |
935 | * preemptible whenever CONFIG_PREEMPT but not CONFIG_HIGHPTE. | |
936 | */ | |
937 | pte = pte_offset_map(pmd, addr); | |
1da177e4 LT |
938 | do { |
939 | /* | |
940 | * swapoff spends a _lot_ of time in this loop! | |
941 | * Test inline before going to call unuse_pte. | |
942 | */ | |
943 | if (unlikely(pte_same(*pte, swp_pte))) { | |
044d66c1 HD |
944 | pte_unmap(pte); |
945 | ret = unuse_pte(vma, pmd, addr, entry, page); | |
946 | if (ret) | |
947 | goto out; | |
948 | pte = pte_offset_map(pmd, addr); | |
1da177e4 LT |
949 | } |
950 | } while (pte++, addr += PAGE_SIZE, addr != end); | |
044d66c1 HD |
951 | pte_unmap(pte - 1); |
952 | out: | |
8a9f3ccd | 953 | return ret; |
1da177e4 LT |
954 | } |
955 | ||
956 | static inline int unuse_pmd_range(struct vm_area_struct *vma, pud_t *pud, | |
957 | unsigned long addr, unsigned long end, | |
958 | swp_entry_t entry, struct page *page) | |
959 | { | |
960 | pmd_t *pmd; | |
961 | unsigned long next; | |
8a9f3ccd | 962 | int ret; |
1da177e4 LT |
963 | |
964 | pmd = pmd_offset(pud, addr); | |
965 | do { | |
966 | next = pmd_addr_end(addr, end); | |
3f04f62f AA |
967 | if (unlikely(pmd_trans_huge(*pmd))) |
968 | continue; | |
1da177e4 LT |
969 | if (pmd_none_or_clear_bad(pmd)) |
970 | continue; | |
8a9f3ccd BS |
971 | ret = unuse_pte_range(vma, pmd, addr, next, entry, page); |
972 | if (ret) | |
973 | return ret; | |
1da177e4 LT |
974 | } while (pmd++, addr = next, addr != end); |
975 | return 0; | |
976 | } | |
977 | ||
978 | static inline int unuse_pud_range(struct vm_area_struct *vma, pgd_t *pgd, | |
979 | unsigned long addr, unsigned long end, | |
980 | swp_entry_t entry, struct page *page) | |
981 | { | |
982 | pud_t *pud; | |
983 | unsigned long next; | |
8a9f3ccd | 984 | int ret; |
1da177e4 LT |
985 | |
986 | pud = pud_offset(pgd, addr); | |
987 | do { | |
988 | next = pud_addr_end(addr, end); | |
989 | if (pud_none_or_clear_bad(pud)) | |
990 | continue; | |
8a9f3ccd BS |
991 | ret = unuse_pmd_range(vma, pud, addr, next, entry, page); |
992 | if (ret) | |
993 | return ret; | |
1da177e4 LT |
994 | } while (pud++, addr = next, addr != end); |
995 | return 0; | |
996 | } | |
997 | ||
998 | static int unuse_vma(struct vm_area_struct *vma, | |
999 | swp_entry_t entry, struct page *page) | |
1000 | { | |
1001 | pgd_t *pgd; | |
1002 | unsigned long addr, end, next; | |
8a9f3ccd | 1003 | int ret; |
1da177e4 | 1004 | |
3ca7b3c5 | 1005 | if (page_anon_vma(page)) { |
1da177e4 LT |
1006 | addr = page_address_in_vma(page, vma); |
1007 | if (addr == -EFAULT) | |
1008 | return 0; | |
1009 | else | |
1010 | end = addr + PAGE_SIZE; | |
1011 | } else { | |
1012 | addr = vma->vm_start; | |
1013 | end = vma->vm_end; | |
1014 | } | |
1015 | ||
1016 | pgd = pgd_offset(vma->vm_mm, addr); | |
1017 | do { | |
1018 | next = pgd_addr_end(addr, end); | |
1019 | if (pgd_none_or_clear_bad(pgd)) | |
1020 | continue; | |
8a9f3ccd BS |
1021 | ret = unuse_pud_range(vma, pgd, addr, next, entry, page); |
1022 | if (ret) | |
1023 | return ret; | |
1da177e4 LT |
1024 | } while (pgd++, addr = next, addr != end); |
1025 | return 0; | |
1026 | } | |
1027 | ||
1028 | static int unuse_mm(struct mm_struct *mm, | |
1029 | swp_entry_t entry, struct page *page) | |
1030 | { | |
1031 | struct vm_area_struct *vma; | |
8a9f3ccd | 1032 | int ret = 0; |
1da177e4 LT |
1033 | |
1034 | if (!down_read_trylock(&mm->mmap_sem)) { | |
1035 | /* | |
7d03431c FLVC |
1036 | * Activate page so shrink_inactive_list is unlikely to unmap |
1037 | * its ptes while lock is dropped, so swapoff can make progress. | |
1da177e4 | 1038 | */ |
c475a8ab | 1039 | activate_page(page); |
1da177e4 LT |
1040 | unlock_page(page); |
1041 | down_read(&mm->mmap_sem); | |
1042 | lock_page(page); | |
1043 | } | |
1da177e4 | 1044 | for (vma = mm->mmap; vma; vma = vma->vm_next) { |
8a9f3ccd | 1045 | if (vma->anon_vma && (ret = unuse_vma(vma, entry, page))) |
1da177e4 LT |
1046 | break; |
1047 | } | |
1da177e4 | 1048 | up_read(&mm->mmap_sem); |
8a9f3ccd | 1049 | return (ret < 0)? ret: 0; |
1da177e4 LT |
1050 | } |
1051 | ||
1052 | /* | |
1053 | * Scan swap_map from current position to next entry still in use. | |
1054 | * Recycle to start on reaching the end, returning 0 when empty. | |
1055 | */ | |
6eb396dc HD |
1056 | static unsigned int find_next_to_unuse(struct swap_info_struct *si, |
1057 | unsigned int prev) | |
1da177e4 | 1058 | { |
6eb396dc HD |
1059 | unsigned int max = si->max; |
1060 | unsigned int i = prev; | |
8d69aaee | 1061 | unsigned char count; |
1da177e4 LT |
1062 | |
1063 | /* | |
5d337b91 | 1064 | * No need for swap_lock here: we're just looking |
1da177e4 LT |
1065 | * for whether an entry is in use, not modifying it; false |
1066 | * hits are okay, and sys_swapoff() has already prevented new | |
5d337b91 | 1067 | * allocations from this area (while holding swap_lock). |
1da177e4 LT |
1068 | */ |
1069 | for (;;) { | |
1070 | if (++i >= max) { | |
1071 | if (!prev) { | |
1072 | i = 0; | |
1073 | break; | |
1074 | } | |
1075 | /* | |
1076 | * No entries in use at top of swap_map, | |
1077 | * loop back to start and recheck there. | |
1078 | */ | |
1079 | max = prev + 1; | |
1080 | prev = 0; | |
1081 | i = 1; | |
1082 | } | |
1083 | count = si->swap_map[i]; | |
355cfa73 | 1084 | if (count && swap_count(count) != SWAP_MAP_BAD) |
1da177e4 LT |
1085 | break; |
1086 | } | |
1087 | return i; | |
1088 | } | |
1089 | ||
1090 | /* | |
1091 | * We completely avoid races by reading each swap page in advance, | |
1092 | * and then search for the process using it. All the necessary | |
1093 | * page table adjustments can then be made atomically. | |
1094 | */ | |
1095 | static int try_to_unuse(unsigned int type) | |
1096 | { | |
efa90a98 | 1097 | struct swap_info_struct *si = swap_info[type]; |
1da177e4 | 1098 | struct mm_struct *start_mm; |
8d69aaee HD |
1099 | unsigned char *swap_map; |
1100 | unsigned char swcount; | |
1da177e4 LT |
1101 | struct page *page; |
1102 | swp_entry_t entry; | |
6eb396dc | 1103 | unsigned int i = 0; |
1da177e4 | 1104 | int retval = 0; |
1da177e4 LT |
1105 | |
1106 | /* | |
1107 | * When searching mms for an entry, a good strategy is to | |
1108 | * start at the first mm we freed the previous entry from | |
1109 | * (though actually we don't notice whether we or coincidence | |
1110 | * freed the entry). Initialize this start_mm with a hold. | |
1111 | * | |
1112 | * A simpler strategy would be to start at the last mm we | |
1113 | * freed the previous entry from; but that would take less | |
1114 | * advantage of mmlist ordering, which clusters forked mms | |
1115 | * together, child after parent. If we race with dup_mmap(), we | |
1116 | * prefer to resolve parent before child, lest we miss entries | |
1117 | * duplicated after we scanned child: using last mm would invert | |
570a335b | 1118 | * that. |
1da177e4 LT |
1119 | */ |
1120 | start_mm = &init_mm; | |
1121 | atomic_inc(&init_mm.mm_users); | |
1122 | ||
1123 | /* | |
1124 | * Keep on scanning until all entries have gone. Usually, | |
1125 | * one pass through swap_map is enough, but not necessarily: | |
1126 | * there are races when an instance of an entry might be missed. | |
1127 | */ | |
1128 | while ((i = find_next_to_unuse(si, i)) != 0) { | |
1129 | if (signal_pending(current)) { | |
1130 | retval = -EINTR; | |
1131 | break; | |
1132 | } | |
1133 | ||
886bb7e9 | 1134 | /* |
1da177e4 LT |
1135 | * Get a page for the entry, using the existing swap |
1136 | * cache page if there is one. Otherwise, get a clean | |
886bb7e9 | 1137 | * page and read the swap into it. |
1da177e4 LT |
1138 | */ |
1139 | swap_map = &si->swap_map[i]; | |
1140 | entry = swp_entry(type, i); | |
02098fea HD |
1141 | page = read_swap_cache_async(entry, |
1142 | GFP_HIGHUSER_MOVABLE, NULL, 0); | |
1da177e4 LT |
1143 | if (!page) { |
1144 | /* | |
1145 | * Either swap_duplicate() failed because entry | |
1146 | * has been freed independently, and will not be | |
1147 | * reused since sys_swapoff() already disabled | |
1148 | * allocation from here, or alloc_page() failed. | |
1149 | */ | |
1150 | if (!*swap_map) | |
1151 | continue; | |
1152 | retval = -ENOMEM; | |
1153 | break; | |
1154 | } | |
1155 | ||
1156 | /* | |
1157 | * Don't hold on to start_mm if it looks like exiting. | |
1158 | */ | |
1159 | if (atomic_read(&start_mm->mm_users) == 1) { | |
1160 | mmput(start_mm); | |
1161 | start_mm = &init_mm; | |
1162 | atomic_inc(&init_mm.mm_users); | |
1163 | } | |
1164 | ||
1165 | /* | |
1166 | * Wait for and lock page. When do_swap_page races with | |
1167 | * try_to_unuse, do_swap_page can handle the fault much | |
1168 | * faster than try_to_unuse can locate the entry. This | |
1169 | * apparently redundant "wait_on_page_locked" lets try_to_unuse | |
1170 | * defer to do_swap_page in such a case - in some tests, | |
1171 | * do_swap_page and try_to_unuse repeatedly compete. | |
1172 | */ | |
1173 | wait_on_page_locked(page); | |
1174 | wait_on_page_writeback(page); | |
1175 | lock_page(page); | |
1176 | wait_on_page_writeback(page); | |
1177 | ||
1178 | /* | |
1179 | * Remove all references to entry. | |
1da177e4 | 1180 | */ |
1da177e4 | 1181 | swcount = *swap_map; |
aaa46865 HD |
1182 | if (swap_count(swcount) == SWAP_MAP_SHMEM) { |
1183 | retval = shmem_unuse(entry, page); | |
1184 | /* page has already been unlocked and released */ | |
1185 | if (retval < 0) | |
1186 | break; | |
1187 | continue; | |
1da177e4 | 1188 | } |
aaa46865 HD |
1189 | if (swap_count(swcount) && start_mm != &init_mm) |
1190 | retval = unuse_mm(start_mm, entry, page); | |
1191 | ||
355cfa73 | 1192 | if (swap_count(*swap_map)) { |
1da177e4 LT |
1193 | int set_start_mm = (*swap_map >= swcount); |
1194 | struct list_head *p = &start_mm->mmlist; | |
1195 | struct mm_struct *new_start_mm = start_mm; | |
1196 | struct mm_struct *prev_mm = start_mm; | |
1197 | struct mm_struct *mm; | |
1198 | ||
1199 | atomic_inc(&new_start_mm->mm_users); | |
1200 | atomic_inc(&prev_mm->mm_users); | |
1201 | spin_lock(&mmlist_lock); | |
aaa46865 | 1202 | while (swap_count(*swap_map) && !retval && |
1da177e4 LT |
1203 | (p = p->next) != &start_mm->mmlist) { |
1204 | mm = list_entry(p, struct mm_struct, mmlist); | |
70af7c5c | 1205 | if (!atomic_inc_not_zero(&mm->mm_users)) |
1da177e4 | 1206 | continue; |
1da177e4 LT |
1207 | spin_unlock(&mmlist_lock); |
1208 | mmput(prev_mm); | |
1209 | prev_mm = mm; | |
1210 | ||
1211 | cond_resched(); | |
1212 | ||
1213 | swcount = *swap_map; | |
355cfa73 | 1214 | if (!swap_count(swcount)) /* any usage ? */ |
1da177e4 | 1215 | ; |
aaa46865 | 1216 | else if (mm == &init_mm) |
1da177e4 | 1217 | set_start_mm = 1; |
aaa46865 | 1218 | else |
1da177e4 | 1219 | retval = unuse_mm(mm, entry, page); |
355cfa73 | 1220 | |
32c5fc10 | 1221 | if (set_start_mm && *swap_map < swcount) { |
1da177e4 LT |
1222 | mmput(new_start_mm); |
1223 | atomic_inc(&mm->mm_users); | |
1224 | new_start_mm = mm; | |
1225 | set_start_mm = 0; | |
1226 | } | |
1227 | spin_lock(&mmlist_lock); | |
1228 | } | |
1229 | spin_unlock(&mmlist_lock); | |
1230 | mmput(prev_mm); | |
1231 | mmput(start_mm); | |
1232 | start_mm = new_start_mm; | |
1233 | } | |
1234 | if (retval) { | |
1235 | unlock_page(page); | |
1236 | page_cache_release(page); | |
1237 | break; | |
1238 | } | |
1239 | ||
1da177e4 LT |
1240 | /* |
1241 | * If a reference remains (rare), we would like to leave | |
1242 | * the page in the swap cache; but try_to_unmap could | |
1243 | * then re-duplicate the entry once we drop page lock, | |
1244 | * so we might loop indefinitely; also, that page could | |
1245 | * not be swapped out to other storage meanwhile. So: | |
1246 | * delete from cache even if there's another reference, | |
1247 | * after ensuring that the data has been saved to disk - | |
1248 | * since if the reference remains (rarer), it will be | |
1249 | * read from disk into another page. Splitting into two | |
1250 | * pages would be incorrect if swap supported "shared | |
1251 | * private" pages, but they are handled by tmpfs files. | |
5ad64688 HD |
1252 | * |
1253 | * Given how unuse_vma() targets one particular offset | |
1254 | * in an anon_vma, once the anon_vma has been determined, | |
1255 | * this splitting happens to be just what is needed to | |
1256 | * handle where KSM pages have been swapped out: re-reading | |
1257 | * is unnecessarily slow, but we can fix that later on. | |
1da177e4 | 1258 | */ |
355cfa73 KH |
1259 | if (swap_count(*swap_map) && |
1260 | PageDirty(page) && PageSwapCache(page)) { | |
1da177e4 LT |
1261 | struct writeback_control wbc = { |
1262 | .sync_mode = WB_SYNC_NONE, | |
1263 | }; | |
1264 | ||
1265 | swap_writepage(page, &wbc); | |
1266 | lock_page(page); | |
1267 | wait_on_page_writeback(page); | |
1268 | } | |
68bdc8d6 HD |
1269 | |
1270 | /* | |
1271 | * It is conceivable that a racing task removed this page from | |
1272 | * swap cache just before we acquired the page lock at the top, | |
1273 | * or while we dropped it in unuse_mm(). The page might even | |
1274 | * be back in swap cache on another swap area: that we must not | |
1275 | * delete, since it may not have been written out to swap yet. | |
1276 | */ | |
1277 | if (PageSwapCache(page) && | |
1278 | likely(page_private(page) == entry.val)) | |
2e0e26c7 | 1279 | delete_from_swap_cache(page); |
1da177e4 LT |
1280 | |
1281 | /* | |
1282 | * So we could skip searching mms once swap count went | |
1283 | * to 1, we did not mark any present ptes as dirty: must | |
2706a1b8 | 1284 | * mark page dirty so shrink_page_list will preserve it. |
1da177e4 LT |
1285 | */ |
1286 | SetPageDirty(page); | |
1287 | unlock_page(page); | |
1288 | page_cache_release(page); | |
1289 | ||
1290 | /* | |
1291 | * Make sure that we aren't completely killing | |
1292 | * interactive performance. | |
1293 | */ | |
1294 | cond_resched(); | |
1295 | } | |
1296 | ||
1297 | mmput(start_mm); | |
1da177e4 LT |
1298 | return retval; |
1299 | } | |
1300 | ||
1301 | /* | |
5d337b91 HD |
1302 | * After a successful try_to_unuse, if no swap is now in use, we know |
1303 | * we can empty the mmlist. swap_lock must be held on entry and exit. | |
1304 | * Note that mmlist_lock nests inside swap_lock, and an mm must be | |
1da177e4 LT |
1305 | * added to the mmlist just after page_duplicate - before would be racy. |
1306 | */ | |
1307 | static void drain_mmlist(void) | |
1308 | { | |
1309 | struct list_head *p, *next; | |
efa90a98 | 1310 | unsigned int type; |
1da177e4 | 1311 | |
efa90a98 HD |
1312 | for (type = 0; type < nr_swapfiles; type++) |
1313 | if (swap_info[type]->inuse_pages) | |
1da177e4 LT |
1314 | return; |
1315 | spin_lock(&mmlist_lock); | |
1316 | list_for_each_safe(p, next, &init_mm.mmlist) | |
1317 | list_del_init(p); | |
1318 | spin_unlock(&mmlist_lock); | |
1319 | } | |
1320 | ||
1321 | /* | |
1322 | * Use this swapdev's extent info to locate the (PAGE_SIZE) block which | |
d4906e1a LS |
1323 | * corresponds to page offset for the specified swap entry. |
1324 | * Note that the type of this function is sector_t, but it returns page offset | |
1325 | * into the bdev, not sector offset. | |
1da177e4 | 1326 | */ |
d4906e1a | 1327 | static sector_t map_swap_entry(swp_entry_t entry, struct block_device **bdev) |
1da177e4 | 1328 | { |
f29ad6a9 HD |
1329 | struct swap_info_struct *sis; |
1330 | struct swap_extent *start_se; | |
1331 | struct swap_extent *se; | |
1332 | pgoff_t offset; | |
1333 | ||
efa90a98 | 1334 | sis = swap_info[swp_type(entry)]; |
f29ad6a9 HD |
1335 | *bdev = sis->bdev; |
1336 | ||
1337 | offset = swp_offset(entry); | |
1338 | start_se = sis->curr_swap_extent; | |
1339 | se = start_se; | |
1da177e4 LT |
1340 | |
1341 | for ( ; ; ) { | |
1342 | struct list_head *lh; | |
1343 | ||
1344 | if (se->start_page <= offset && | |
1345 | offset < (se->start_page + se->nr_pages)) { | |
1346 | return se->start_block + (offset - se->start_page); | |
1347 | } | |
11d31886 | 1348 | lh = se->list.next; |
1da177e4 LT |
1349 | se = list_entry(lh, struct swap_extent, list); |
1350 | sis->curr_swap_extent = se; | |
1351 | BUG_ON(se == start_se); /* It *must* be present */ | |
1352 | } | |
1353 | } | |
1354 | ||
d4906e1a LS |
1355 | /* |
1356 | * Returns the page offset into bdev for the specified page's swap entry. | |
1357 | */ | |
1358 | sector_t map_swap_page(struct page *page, struct block_device **bdev) | |
1359 | { | |
1360 | swp_entry_t entry; | |
1361 | entry.val = page_private(page); | |
1362 | return map_swap_entry(entry, bdev); | |
1363 | } | |
1364 | ||
1da177e4 LT |
1365 | /* |
1366 | * Free all of a swapdev's extent information | |
1367 | */ | |
1368 | static void destroy_swap_extents(struct swap_info_struct *sis) | |
1369 | { | |
9625a5f2 | 1370 | while (!list_empty(&sis->first_swap_extent.list)) { |
1da177e4 LT |
1371 | struct swap_extent *se; |
1372 | ||
9625a5f2 | 1373 | se = list_entry(sis->first_swap_extent.list.next, |
1da177e4 LT |
1374 | struct swap_extent, list); |
1375 | list_del(&se->list); | |
1376 | kfree(se); | |
1377 | } | |
1da177e4 LT |
1378 | } |
1379 | ||
1380 | /* | |
1381 | * Add a block range (and the corresponding page range) into this swapdev's | |
11d31886 | 1382 | * extent list. The extent list is kept sorted in page order. |
1da177e4 | 1383 | * |
11d31886 | 1384 | * This function rather assumes that it is called in ascending page order. |
1da177e4 LT |
1385 | */ |
1386 | static int | |
1387 | add_swap_extent(struct swap_info_struct *sis, unsigned long start_page, | |
1388 | unsigned long nr_pages, sector_t start_block) | |
1389 | { | |
1390 | struct swap_extent *se; | |
1391 | struct swap_extent *new_se; | |
1392 | struct list_head *lh; | |
1393 | ||
9625a5f2 HD |
1394 | if (start_page == 0) { |
1395 | se = &sis->first_swap_extent; | |
1396 | sis->curr_swap_extent = se; | |
1397 | se->start_page = 0; | |
1398 | se->nr_pages = nr_pages; | |
1399 | se->start_block = start_block; | |
1400 | return 1; | |
1401 | } else { | |
1402 | lh = sis->first_swap_extent.list.prev; /* Highest extent */ | |
1da177e4 | 1403 | se = list_entry(lh, struct swap_extent, list); |
11d31886 HD |
1404 | BUG_ON(se->start_page + se->nr_pages != start_page); |
1405 | if (se->start_block + se->nr_pages == start_block) { | |
1da177e4 LT |
1406 | /* Merge it */ |
1407 | se->nr_pages += nr_pages; | |
1408 | return 0; | |
1409 | } | |
1da177e4 LT |
1410 | } |
1411 | ||
1412 | /* | |
1413 | * No merge. Insert a new extent, preserving ordering. | |
1414 | */ | |
1415 | new_se = kmalloc(sizeof(*se), GFP_KERNEL); | |
1416 | if (new_se == NULL) | |
1417 | return -ENOMEM; | |
1418 | new_se->start_page = start_page; | |
1419 | new_se->nr_pages = nr_pages; | |
1420 | new_se->start_block = start_block; | |
1421 | ||
9625a5f2 | 1422 | list_add_tail(&new_se->list, &sis->first_swap_extent.list); |
53092a74 | 1423 | return 1; |
1da177e4 LT |
1424 | } |
1425 | ||
1426 | /* | |
1427 | * A `swap extent' is a simple thing which maps a contiguous range of pages | |
1428 | * onto a contiguous range of disk blocks. An ordered list of swap extents | |
1429 | * is built at swapon time and is then used at swap_writepage/swap_readpage | |
1430 | * time for locating where on disk a page belongs. | |
1431 | * | |
1432 | * If the swapfile is an S_ISBLK block device, a single extent is installed. | |
1433 | * This is done so that the main operating code can treat S_ISBLK and S_ISREG | |
1434 | * swap files identically. | |
1435 | * | |
1436 | * Whether the swapdev is an S_ISREG file or an S_ISBLK blockdev, the swap | |
1437 | * extent list operates in PAGE_SIZE disk blocks. Both S_ISREG and S_ISBLK | |
1438 | * swapfiles are handled *identically* after swapon time. | |
1439 | * | |
1440 | * For S_ISREG swapfiles, setup_swap_extents() will walk all the file's blocks | |
1441 | * and will parse them into an ordered extent list, in PAGE_SIZE chunks. If | |
1442 | * some stray blocks are found which do not fall within the PAGE_SIZE alignment | |
1443 | * requirements, they are simply tossed out - we will never use those blocks | |
1444 | * for swapping. | |
1445 | * | |
b0d9bcd4 | 1446 | * For S_ISREG swapfiles we set S_SWAPFILE across the life of the swapon. This |
1da177e4 LT |
1447 | * prevents root from shooting her foot off by ftruncating an in-use swapfile, |
1448 | * which will scribble on the fs. | |
1449 | * | |
1450 | * The amount of disk space which a single swap extent represents varies. | |
1451 | * Typically it is in the 1-4 megabyte range. So we can have hundreds of | |
1452 | * extents in the list. To avoid much list walking, we cache the previous | |
1453 | * search location in `curr_swap_extent', and start new searches from there. | |
1454 | * This is extremely effective. The average number of iterations in | |
1455 | * map_swap_page() has been measured at about 0.3 per page. - akpm. | |
1456 | */ | |
53092a74 | 1457 | static int setup_swap_extents(struct swap_info_struct *sis, sector_t *span) |
1da177e4 LT |
1458 | { |
1459 | struct inode *inode; | |
1460 | unsigned blocks_per_page; | |
1461 | unsigned long page_no; | |
1462 | unsigned blkbits; | |
1463 | sector_t probe_block; | |
1464 | sector_t last_block; | |
53092a74 HD |
1465 | sector_t lowest_block = -1; |
1466 | sector_t highest_block = 0; | |
1467 | int nr_extents = 0; | |
1da177e4 LT |
1468 | int ret; |
1469 | ||
1470 | inode = sis->swap_file->f_mapping->host; | |
1471 | if (S_ISBLK(inode->i_mode)) { | |
1472 | ret = add_swap_extent(sis, 0, sis->max, 0); | |
53092a74 | 1473 | *span = sis->pages; |
9625a5f2 | 1474 | goto out; |
1da177e4 LT |
1475 | } |
1476 | ||
1477 | blkbits = inode->i_blkbits; | |
1478 | blocks_per_page = PAGE_SIZE >> blkbits; | |
1479 | ||
1480 | /* | |
1481 | * Map all the blocks into the extent list. This code doesn't try | |
1482 | * to be very smart. | |
1483 | */ | |
1484 | probe_block = 0; | |
1485 | page_no = 0; | |
1486 | last_block = i_size_read(inode) >> blkbits; | |
1487 | while ((probe_block + blocks_per_page) <= last_block && | |
1488 | page_no < sis->max) { | |
1489 | unsigned block_in_page; | |
1490 | sector_t first_block; | |
1491 | ||
1492 | first_block = bmap(inode, probe_block); | |
1493 | if (first_block == 0) | |
1494 | goto bad_bmap; | |
1495 | ||
1496 | /* | |
1497 | * It must be PAGE_SIZE aligned on-disk | |
1498 | */ | |
1499 | if (first_block & (blocks_per_page - 1)) { | |
1500 | probe_block++; | |
1501 | goto reprobe; | |
1502 | } | |
1503 | ||
1504 | for (block_in_page = 1; block_in_page < blocks_per_page; | |
1505 | block_in_page++) { | |
1506 | sector_t block; | |
1507 | ||
1508 | block = bmap(inode, probe_block + block_in_page); | |
1509 | if (block == 0) | |
1510 | goto bad_bmap; | |
1511 | if (block != first_block + block_in_page) { | |
1512 | /* Discontiguity */ | |
1513 | probe_block++; | |
1514 | goto reprobe; | |
1515 | } | |
1516 | } | |
1517 | ||
53092a74 HD |
1518 | first_block >>= (PAGE_SHIFT - blkbits); |
1519 | if (page_no) { /* exclude the header page */ | |
1520 | if (first_block < lowest_block) | |
1521 | lowest_block = first_block; | |
1522 | if (first_block > highest_block) | |
1523 | highest_block = first_block; | |
1524 | } | |
1525 | ||
1da177e4 LT |
1526 | /* |
1527 | * We found a PAGE_SIZE-length, PAGE_SIZE-aligned run of blocks | |
1528 | */ | |
53092a74 HD |
1529 | ret = add_swap_extent(sis, page_no, 1, first_block); |
1530 | if (ret < 0) | |
1da177e4 | 1531 | goto out; |
53092a74 | 1532 | nr_extents += ret; |
1da177e4 LT |
1533 | page_no++; |
1534 | probe_block += blocks_per_page; | |
1535 | reprobe: | |
1536 | continue; | |
1537 | } | |
53092a74 HD |
1538 | ret = nr_extents; |
1539 | *span = 1 + highest_block - lowest_block; | |
1da177e4 | 1540 | if (page_no == 0) |
e2244ec2 | 1541 | page_no = 1; /* force Empty message */ |
1da177e4 | 1542 | sis->max = page_no; |
e2244ec2 | 1543 | sis->pages = page_no - 1; |
1da177e4 | 1544 | sis->highest_bit = page_no - 1; |
9625a5f2 HD |
1545 | out: |
1546 | return ret; | |
1da177e4 LT |
1547 | bad_bmap: |
1548 | printk(KERN_ERR "swapon: swapfile has holes\n"); | |
1549 | ret = -EINVAL; | |
9625a5f2 | 1550 | goto out; |
1da177e4 LT |
1551 | } |
1552 | ||
c4ea37c2 | 1553 | SYSCALL_DEFINE1(swapoff, const char __user *, specialfile) |
1da177e4 | 1554 | { |
73c34b6a | 1555 | struct swap_info_struct *p = NULL; |
8d69aaee | 1556 | unsigned char *swap_map; |
1da177e4 LT |
1557 | struct file *swap_file, *victim; |
1558 | struct address_space *mapping; | |
1559 | struct inode *inode; | |
73c34b6a | 1560 | char *pathname; |
1da177e4 LT |
1561 | int i, type, prev; |
1562 | int err; | |
886bb7e9 | 1563 | |
1da177e4 LT |
1564 | if (!capable(CAP_SYS_ADMIN)) |
1565 | return -EPERM; | |
1566 | ||
1567 | pathname = getname(specialfile); | |
1568 | err = PTR_ERR(pathname); | |
1569 | if (IS_ERR(pathname)) | |
1570 | goto out; | |
1571 | ||
1572 | victim = filp_open(pathname, O_RDWR|O_LARGEFILE, 0); | |
1573 | putname(pathname); | |
1574 | err = PTR_ERR(victim); | |
1575 | if (IS_ERR(victim)) | |
1576 | goto out; | |
1577 | ||
1578 | mapping = victim->f_mapping; | |
1579 | prev = -1; | |
5d337b91 | 1580 | spin_lock(&swap_lock); |
efa90a98 HD |
1581 | for (type = swap_list.head; type >= 0; type = swap_info[type]->next) { |
1582 | p = swap_info[type]; | |
22c6f8fd | 1583 | if (p->flags & SWP_WRITEOK) { |
1da177e4 LT |
1584 | if (p->swap_file->f_mapping == mapping) |
1585 | break; | |
1586 | } | |
1587 | prev = type; | |
1588 | } | |
1589 | if (type < 0) { | |
1590 | err = -EINVAL; | |
5d337b91 | 1591 | spin_unlock(&swap_lock); |
1da177e4 LT |
1592 | goto out_dput; |
1593 | } | |
1594 | if (!security_vm_enough_memory(p->pages)) | |
1595 | vm_unacct_memory(p->pages); | |
1596 | else { | |
1597 | err = -ENOMEM; | |
5d337b91 | 1598 | spin_unlock(&swap_lock); |
1da177e4 LT |
1599 | goto out_dput; |
1600 | } | |
efa90a98 | 1601 | if (prev < 0) |
1da177e4 | 1602 | swap_list.head = p->next; |
efa90a98 HD |
1603 | else |
1604 | swap_info[prev]->next = p->next; | |
1da177e4 LT |
1605 | if (type == swap_list.next) { |
1606 | /* just pick something that's safe... */ | |
1607 | swap_list.next = swap_list.head; | |
1608 | } | |
78ecba08 | 1609 | if (p->prio < 0) { |
efa90a98 HD |
1610 | for (i = p->next; i >= 0; i = swap_info[i]->next) |
1611 | swap_info[i]->prio = p->prio--; | |
78ecba08 HD |
1612 | least_priority++; |
1613 | } | |
1da177e4 LT |
1614 | nr_swap_pages -= p->pages; |
1615 | total_swap_pages -= p->pages; | |
1616 | p->flags &= ~SWP_WRITEOK; | |
5d337b91 | 1617 | spin_unlock(&swap_lock); |
fb4f88dc | 1618 | |
35451bee | 1619 | current->flags |= PF_OOM_ORIGIN; |
1da177e4 | 1620 | err = try_to_unuse(type); |
35451bee | 1621 | current->flags &= ~PF_OOM_ORIGIN; |
1da177e4 | 1622 | |
1da177e4 LT |
1623 | if (err) { |
1624 | /* re-insert swap space back into swap_list */ | |
5d337b91 | 1625 | spin_lock(&swap_lock); |
78ecba08 HD |
1626 | if (p->prio < 0) |
1627 | p->prio = --least_priority; | |
1628 | prev = -1; | |
efa90a98 HD |
1629 | for (i = swap_list.head; i >= 0; i = swap_info[i]->next) { |
1630 | if (p->prio >= swap_info[i]->prio) | |
1da177e4 | 1631 | break; |
78ecba08 HD |
1632 | prev = i; |
1633 | } | |
1da177e4 LT |
1634 | p->next = i; |
1635 | if (prev < 0) | |
efa90a98 | 1636 | swap_list.head = swap_list.next = type; |
1da177e4 | 1637 | else |
efa90a98 | 1638 | swap_info[prev]->next = type; |
1da177e4 LT |
1639 | nr_swap_pages += p->pages; |
1640 | total_swap_pages += p->pages; | |
1641 | p->flags |= SWP_WRITEOK; | |
5d337b91 | 1642 | spin_unlock(&swap_lock); |
1da177e4 LT |
1643 | goto out_dput; |
1644 | } | |
52b7efdb HD |
1645 | |
1646 | /* wait for any unplug function to finish */ | |
1647 | down_write(&swap_unplug_sem); | |
1648 | up_write(&swap_unplug_sem); | |
1649 | ||
5d337b91 | 1650 | destroy_swap_extents(p); |
570a335b HD |
1651 | if (p->flags & SWP_CONTINUED) |
1652 | free_swap_count_continuations(p); | |
1653 | ||
fc0abb14 | 1654 | mutex_lock(&swapon_mutex); |
5d337b91 HD |
1655 | spin_lock(&swap_lock); |
1656 | drain_mmlist(); | |
1657 | ||
52b7efdb | 1658 | /* wait for anyone still in scan_swap_map */ |
52b7efdb HD |
1659 | p->highest_bit = 0; /* cuts scans short */ |
1660 | while (p->flags >= SWP_SCANNING) { | |
5d337b91 | 1661 | spin_unlock(&swap_lock); |
13e4b57f | 1662 | schedule_timeout_uninterruptible(1); |
5d337b91 | 1663 | spin_lock(&swap_lock); |
52b7efdb | 1664 | } |
52b7efdb | 1665 | |
1da177e4 LT |
1666 | swap_file = p->swap_file; |
1667 | p->swap_file = NULL; | |
1668 | p->max = 0; | |
1669 | swap_map = p->swap_map; | |
1670 | p->swap_map = NULL; | |
1671 | p->flags = 0; | |
5d337b91 | 1672 | spin_unlock(&swap_lock); |
fc0abb14 | 1673 | mutex_unlock(&swapon_mutex); |
1da177e4 | 1674 | vfree(swap_map); |
27a7faa0 KH |
1675 | /* Destroy swap account informatin */ |
1676 | swap_cgroup_swapoff(type); | |
1677 | ||
1da177e4 LT |
1678 | inode = mapping->host; |
1679 | if (S_ISBLK(inode->i_mode)) { | |
1680 | struct block_device *bdev = I_BDEV(inode); | |
1681 | set_blocksize(bdev, p->old_block_size); | |
e525fd89 | 1682 | blkdev_put(bdev, FMODE_READ | FMODE_WRITE | FMODE_EXCL); |
1da177e4 | 1683 | } else { |
1b1dcc1b | 1684 | mutex_lock(&inode->i_mutex); |
1da177e4 | 1685 | inode->i_flags &= ~S_SWAPFILE; |
1b1dcc1b | 1686 | mutex_unlock(&inode->i_mutex); |
1da177e4 LT |
1687 | } |
1688 | filp_close(swap_file, NULL); | |
1689 | err = 0; | |
66d7dd51 KS |
1690 | atomic_inc(&proc_poll_event); |
1691 | wake_up_interruptible(&proc_poll_wait); | |
1da177e4 LT |
1692 | |
1693 | out_dput: | |
1694 | filp_close(victim, NULL); | |
1695 | out: | |
1696 | return err; | |
1697 | } | |
1698 | ||
1699 | #ifdef CONFIG_PROC_FS | |
66d7dd51 KS |
1700 | struct proc_swaps { |
1701 | struct seq_file seq; | |
1702 | int event; | |
1703 | }; | |
1704 | ||
1705 | static unsigned swaps_poll(struct file *file, poll_table *wait) | |
1706 | { | |
1707 | struct proc_swaps *s = file->private_data; | |
1708 | ||
1709 | poll_wait(file, &proc_poll_wait, wait); | |
1710 | ||
1711 | if (s->event != atomic_read(&proc_poll_event)) { | |
1712 | s->event = atomic_read(&proc_poll_event); | |
1713 | return POLLIN | POLLRDNORM | POLLERR | POLLPRI; | |
1714 | } | |
1715 | ||
1716 | return POLLIN | POLLRDNORM; | |
1717 | } | |
1718 | ||
1da177e4 LT |
1719 | /* iterator */ |
1720 | static void *swap_start(struct seq_file *swap, loff_t *pos) | |
1721 | { | |
efa90a98 HD |
1722 | struct swap_info_struct *si; |
1723 | int type; | |
1da177e4 LT |
1724 | loff_t l = *pos; |
1725 | ||
fc0abb14 | 1726 | mutex_lock(&swapon_mutex); |
1da177e4 | 1727 | |
881e4aab SS |
1728 | if (!l) |
1729 | return SEQ_START_TOKEN; | |
1730 | ||
efa90a98 HD |
1731 | for (type = 0; type < nr_swapfiles; type++) { |
1732 | smp_rmb(); /* read nr_swapfiles before swap_info[type] */ | |
1733 | si = swap_info[type]; | |
1734 | if (!(si->flags & SWP_USED) || !si->swap_map) | |
1da177e4 | 1735 | continue; |
881e4aab | 1736 | if (!--l) |
efa90a98 | 1737 | return si; |
1da177e4 LT |
1738 | } |
1739 | ||
1740 | return NULL; | |
1741 | } | |
1742 | ||
1743 | static void *swap_next(struct seq_file *swap, void *v, loff_t *pos) | |
1744 | { | |
efa90a98 HD |
1745 | struct swap_info_struct *si = v; |
1746 | int type; | |
1da177e4 | 1747 | |
881e4aab | 1748 | if (v == SEQ_START_TOKEN) |
efa90a98 HD |
1749 | type = 0; |
1750 | else | |
1751 | type = si->type + 1; | |
881e4aab | 1752 | |
efa90a98 HD |
1753 | for (; type < nr_swapfiles; type++) { |
1754 | smp_rmb(); /* read nr_swapfiles before swap_info[type] */ | |
1755 | si = swap_info[type]; | |
1756 | if (!(si->flags & SWP_USED) || !si->swap_map) | |
1da177e4 LT |
1757 | continue; |
1758 | ++*pos; | |
efa90a98 | 1759 | return si; |
1da177e4 LT |
1760 | } |
1761 | ||
1762 | return NULL; | |
1763 | } | |
1764 | ||
1765 | static void swap_stop(struct seq_file *swap, void *v) | |
1766 | { | |
fc0abb14 | 1767 | mutex_unlock(&swapon_mutex); |
1da177e4 LT |
1768 | } |
1769 | ||
1770 | static int swap_show(struct seq_file *swap, void *v) | |
1771 | { | |
efa90a98 | 1772 | struct swap_info_struct *si = v; |
1da177e4 LT |
1773 | struct file *file; |
1774 | int len; | |
1775 | ||
efa90a98 | 1776 | if (si == SEQ_START_TOKEN) { |
881e4aab SS |
1777 | seq_puts(swap,"Filename\t\t\t\tType\t\tSize\tUsed\tPriority\n"); |
1778 | return 0; | |
1779 | } | |
1da177e4 | 1780 | |
efa90a98 | 1781 | file = si->swap_file; |
c32c2f63 | 1782 | len = seq_path(swap, &file->f_path, " \t\n\\"); |
6eb396dc | 1783 | seq_printf(swap, "%*s%s\t%u\t%u\t%d\n", |
886bb7e9 HD |
1784 | len < 40 ? 40 - len : 1, " ", |
1785 | S_ISBLK(file->f_path.dentry->d_inode->i_mode) ? | |
1da177e4 | 1786 | "partition" : "file\t", |
efa90a98 HD |
1787 | si->pages << (PAGE_SHIFT - 10), |
1788 | si->inuse_pages << (PAGE_SHIFT - 10), | |
1789 | si->prio); | |
1da177e4 LT |
1790 | return 0; |
1791 | } | |
1792 | ||
15ad7cdc | 1793 | static const struct seq_operations swaps_op = { |
1da177e4 LT |
1794 | .start = swap_start, |
1795 | .next = swap_next, | |
1796 | .stop = swap_stop, | |
1797 | .show = swap_show | |
1798 | }; | |
1799 | ||
1800 | static int swaps_open(struct inode *inode, struct file *file) | |
1801 | { | |
66d7dd51 KS |
1802 | struct proc_swaps *s; |
1803 | int ret; | |
1804 | ||
1805 | s = kmalloc(sizeof(struct proc_swaps), GFP_KERNEL); | |
1806 | if (!s) | |
1807 | return -ENOMEM; | |
1808 | ||
1809 | file->private_data = s; | |
1810 | ||
1811 | ret = seq_open(file, &swaps_op); | |
1812 | if (ret) { | |
1813 | kfree(s); | |
1814 | return ret; | |
1815 | } | |
1816 | ||
1817 | s->seq.private = s; | |
1818 | s->event = atomic_read(&proc_poll_event); | |
1819 | return ret; | |
1da177e4 LT |
1820 | } |
1821 | ||
15ad7cdc | 1822 | static const struct file_operations proc_swaps_operations = { |
1da177e4 LT |
1823 | .open = swaps_open, |
1824 | .read = seq_read, | |
1825 | .llseek = seq_lseek, | |
1826 | .release = seq_release, | |
66d7dd51 | 1827 | .poll = swaps_poll, |
1da177e4 LT |
1828 | }; |
1829 | ||
1830 | static int __init procswaps_init(void) | |
1831 | { | |
3d71f86f | 1832 | proc_create("swaps", 0, NULL, &proc_swaps_operations); |
1da177e4 LT |
1833 | return 0; |
1834 | } | |
1835 | __initcall(procswaps_init); | |
1836 | #endif /* CONFIG_PROC_FS */ | |
1837 | ||
1796316a JB |
1838 | #ifdef MAX_SWAPFILES_CHECK |
1839 | static int __init max_swapfiles_check(void) | |
1840 | { | |
1841 | MAX_SWAPFILES_CHECK(); | |
1842 | return 0; | |
1843 | } | |
1844 | late_initcall(max_swapfiles_check); | |
1845 | #endif | |
1846 | ||
1da177e4 LT |
1847 | /* |
1848 | * Written 01/25/92 by Simmule Turner, heavily changed by Linus. | |
1849 | * | |
1850 | * The swapon system call | |
1851 | */ | |
c4ea37c2 | 1852 | SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags) |
1da177e4 | 1853 | { |
73c34b6a | 1854 | struct swap_info_struct *p; |
1da177e4 LT |
1855 | char *name = NULL; |
1856 | struct block_device *bdev = NULL; | |
1857 | struct file *swap_file = NULL; | |
1858 | struct address_space *mapping; | |
1859 | unsigned int type; | |
1860 | int i, prev; | |
1861 | int error; | |
ad2bd7e0 HD |
1862 | union swap_header *swap_header; |
1863 | unsigned int nr_good_pages; | |
6eb396dc | 1864 | int nr_extents = 0; |
53092a74 | 1865 | sector_t span; |
ad2bd7e0 | 1866 | unsigned long maxpages; |
73fd8748 | 1867 | unsigned long swapfilepages; |
8d69aaee | 1868 | unsigned char *swap_map = NULL; |
1da177e4 LT |
1869 | struct page *page = NULL; |
1870 | struct inode *inode = NULL; | |
1871 | int did_down = 0; | |
1872 | ||
1873 | if (!capable(CAP_SYS_ADMIN)) | |
1874 | return -EPERM; | |
efa90a98 HD |
1875 | |
1876 | p = kzalloc(sizeof(*p), GFP_KERNEL); | |
1877 | if (!p) | |
1878 | return -ENOMEM; | |
1879 | ||
5d337b91 | 1880 | spin_lock(&swap_lock); |
efa90a98 HD |
1881 | for (type = 0; type < nr_swapfiles; type++) { |
1882 | if (!(swap_info[type]->flags & SWP_USED)) | |
1da177e4 | 1883 | break; |
efa90a98 | 1884 | } |
1da177e4 | 1885 | error = -EPERM; |
0697212a | 1886 | if (type >= MAX_SWAPFILES) { |
5d337b91 | 1887 | spin_unlock(&swap_lock); |
efa90a98 | 1888 | kfree(p); |
1da177e4 LT |
1889 | goto out; |
1890 | } | |
efa90a98 HD |
1891 | if (type >= nr_swapfiles) { |
1892 | p->type = type; | |
1893 | swap_info[type] = p; | |
1894 | /* | |
1895 | * Write swap_info[type] before nr_swapfiles, in case a | |
1896 | * racing procfs swap_start() or swap_next() is reading them. | |
1897 | * (We never shrink nr_swapfiles, we never free this entry.) | |
1898 | */ | |
1899 | smp_wmb(); | |
1900 | nr_swapfiles++; | |
1901 | } else { | |
1902 | kfree(p); | |
1903 | p = swap_info[type]; | |
1904 | /* | |
1905 | * Do not memset this entry: a racing procfs swap_next() | |
1906 | * would be relying on p->type to remain valid. | |
1907 | */ | |
1908 | } | |
9625a5f2 | 1909 | INIT_LIST_HEAD(&p->first_swap_extent.list); |
1da177e4 | 1910 | p->flags = SWP_USED; |
1da177e4 | 1911 | p->next = -1; |
5d337b91 | 1912 | spin_unlock(&swap_lock); |
efa90a98 | 1913 | |
1da177e4 LT |
1914 | name = getname(specialfile); |
1915 | error = PTR_ERR(name); | |
1916 | if (IS_ERR(name)) { | |
1917 | name = NULL; | |
1918 | goto bad_swap_2; | |
1919 | } | |
1920 | swap_file = filp_open(name, O_RDWR|O_LARGEFILE, 0); | |
1921 | error = PTR_ERR(swap_file); | |
1922 | if (IS_ERR(swap_file)) { | |
1923 | swap_file = NULL; | |
1924 | goto bad_swap_2; | |
1925 | } | |
1926 | ||
1927 | p->swap_file = swap_file; | |
1928 | mapping = swap_file->f_mapping; | |
1929 | inode = mapping->host; | |
1930 | ||
1931 | error = -EBUSY; | |
1932 | for (i = 0; i < nr_swapfiles; i++) { | |
efa90a98 | 1933 | struct swap_info_struct *q = swap_info[i]; |
1da177e4 LT |
1934 | |
1935 | if (i == type || !q->swap_file) | |
1936 | continue; | |
1937 | if (mapping == q->swap_file->f_mapping) | |
1938 | goto bad_swap; | |
1939 | } | |
1940 | ||
1941 | error = -EINVAL; | |
1942 | if (S_ISBLK(inode->i_mode)) { | |
8074b26f | 1943 | bdev = bdgrab(I_BDEV(inode)); |
e525fd89 TH |
1944 | error = blkdev_get(bdev, FMODE_READ | FMODE_WRITE | FMODE_EXCL, |
1945 | sys_swapon); | |
1da177e4 LT |
1946 | if (error < 0) { |
1947 | bdev = NULL; | |
f7b3a435 | 1948 | error = -EINVAL; |
1da177e4 LT |
1949 | goto bad_swap; |
1950 | } | |
1951 | p->old_block_size = block_size(bdev); | |
1952 | error = set_blocksize(bdev, PAGE_SIZE); | |
1953 | if (error < 0) | |
1954 | goto bad_swap; | |
1955 | p->bdev = bdev; | |
b2725643 | 1956 | p->flags |= SWP_BLKDEV; |
1da177e4 LT |
1957 | } else if (S_ISREG(inode->i_mode)) { |
1958 | p->bdev = inode->i_sb->s_bdev; | |
1b1dcc1b | 1959 | mutex_lock(&inode->i_mutex); |
1da177e4 LT |
1960 | did_down = 1; |
1961 | if (IS_SWAPFILE(inode)) { | |
1962 | error = -EBUSY; | |
1963 | goto bad_swap; | |
1964 | } | |
1965 | } else { | |
1966 | goto bad_swap; | |
1967 | } | |
1968 | ||
73fd8748 | 1969 | swapfilepages = i_size_read(inode) >> PAGE_SHIFT; |
1da177e4 LT |
1970 | |
1971 | /* | |
1972 | * Read the swap header. | |
1973 | */ | |
1974 | if (!mapping->a_ops->readpage) { | |
1975 | error = -EINVAL; | |
1976 | goto bad_swap; | |
1977 | } | |
090d2b18 | 1978 | page = read_mapping_page(mapping, 0, swap_file); |
1da177e4 LT |
1979 | if (IS_ERR(page)) { |
1980 | error = PTR_ERR(page); | |
1981 | goto bad_swap; | |
1982 | } | |
81e33971 | 1983 | swap_header = kmap(page); |
1da177e4 | 1984 | |
81e33971 | 1985 | if (memcmp("SWAPSPACE2", swap_header->magic.magic, 10)) { |
e97a3111 | 1986 | printk(KERN_ERR "Unable to find swap-space signature\n"); |
1da177e4 LT |
1987 | error = -EINVAL; |
1988 | goto bad_swap; | |
1989 | } | |
886bb7e9 | 1990 | |
81e33971 HD |
1991 | /* swap partition endianess hack... */ |
1992 | if (swab32(swap_header->info.version) == 1) { | |
1993 | swab32s(&swap_header->info.version); | |
1994 | swab32s(&swap_header->info.last_page); | |
1995 | swab32s(&swap_header->info.nr_badpages); | |
1996 | for (i = 0; i < swap_header->info.nr_badpages; i++) | |
1997 | swab32s(&swap_header->info.badpages[i]); | |
1998 | } | |
1999 | /* Check the swap header's sub-version */ | |
2000 | if (swap_header->info.version != 1) { | |
2001 | printk(KERN_WARNING | |
2002 | "Unable to handle swap header version %d\n", | |
2003 | swap_header->info.version); | |
1da177e4 LT |
2004 | error = -EINVAL; |
2005 | goto bad_swap; | |
81e33971 | 2006 | } |
1da177e4 | 2007 | |
81e33971 HD |
2008 | p->lowest_bit = 1; |
2009 | p->cluster_next = 1; | |
efa90a98 | 2010 | p->cluster_nr = 0; |
52b7efdb | 2011 | |
81e33971 HD |
2012 | /* |
2013 | * Find out how many pages are allowed for a single swap | |
2014 | * device. There are two limiting factors: 1) the number of | |
2015 | * bits for the swap offset in the swp_entry_t type and | |
2016 | * 2) the number of bits in the a swap pte as defined by | |
2017 | * the different architectures. In order to find the | |
2018 | * largest possible bit mask a swap entry with swap type 0 | |
2019 | * and swap offset ~0UL is created, encoded to a swap pte, | |
2020 | * decoded to a swp_entry_t again and finally the swap | |
2021 | * offset is extracted. This will mask all the bits from | |
2022 | * the initial ~0UL mask that can't be encoded in either | |
2023 | * the swp_entry_t or the architecture definition of a | |
2024 | * swap pte. | |
2025 | */ | |
2026 | maxpages = swp_offset(pte_to_swp_entry( | |
ad2bd7e0 HD |
2027 | swp_entry_to_pte(swp_entry(0, ~0UL)))) + 1; |
2028 | if (maxpages > swap_header->info.last_page) { | |
2029 | maxpages = swap_header->info.last_page + 1; | |
2030 | /* p->max is an unsigned int: don't overflow it */ | |
2031 | if ((unsigned int)maxpages == 0) | |
2032 | maxpages = UINT_MAX; | |
2033 | } | |
81e33971 | 2034 | p->highest_bit = maxpages - 1; |
1da177e4 | 2035 | |
81e33971 HD |
2036 | error = -EINVAL; |
2037 | if (!maxpages) | |
2038 | goto bad_swap; | |
2039 | if (swapfilepages && maxpages > swapfilepages) { | |
2040 | printk(KERN_WARNING | |
2041 | "Swap area shorter than signature indicates\n"); | |
2042 | goto bad_swap; | |
2043 | } | |
2044 | if (swap_header->info.nr_badpages && S_ISREG(inode->i_mode)) | |
2045 | goto bad_swap; | |
2046 | if (swap_header->info.nr_badpages > MAX_SWAP_BADPAGES) | |
2047 | goto bad_swap; | |
cd105df4 | 2048 | |
81e33971 | 2049 | /* OK, set up the swap map and apply the bad block list */ |
8d69aaee | 2050 | swap_map = vmalloc(maxpages); |
81e33971 HD |
2051 | if (!swap_map) { |
2052 | error = -ENOMEM; | |
2053 | goto bad_swap; | |
2054 | } | |
1da177e4 | 2055 | |
8d69aaee | 2056 | memset(swap_map, 0, maxpages); |
ad2bd7e0 HD |
2057 | nr_good_pages = maxpages - 1; /* omit header page */ |
2058 | ||
81e33971 | 2059 | for (i = 0; i < swap_header->info.nr_badpages; i++) { |
ad2bd7e0 HD |
2060 | unsigned int page_nr = swap_header->info.badpages[i]; |
2061 | if (page_nr == 0 || page_nr > swap_header->info.last_page) { | |
81e33971 | 2062 | error = -EINVAL; |
1da177e4 | 2063 | goto bad_swap; |
81e33971 | 2064 | } |
ad2bd7e0 HD |
2065 | if (page_nr < maxpages) { |
2066 | swap_map[page_nr] = SWAP_MAP_BAD; | |
2067 | nr_good_pages--; | |
2068 | } | |
1da177e4 | 2069 | } |
27a7faa0 KH |
2070 | |
2071 | error = swap_cgroup_swapon(type, maxpages); | |
2072 | if (error) | |
2073 | goto bad_swap; | |
2074 | ||
e2244ec2 | 2075 | if (nr_good_pages) { |
78ecba08 | 2076 | swap_map[0] = SWAP_MAP_BAD; |
e2244ec2 HD |
2077 | p->max = maxpages; |
2078 | p->pages = nr_good_pages; | |
53092a74 HD |
2079 | nr_extents = setup_swap_extents(p, &span); |
2080 | if (nr_extents < 0) { | |
2081 | error = nr_extents; | |
e2244ec2 | 2082 | goto bad_swap; |
53092a74 | 2083 | } |
e2244ec2 HD |
2084 | nr_good_pages = p->pages; |
2085 | } | |
1da177e4 LT |
2086 | if (!nr_good_pages) { |
2087 | printk(KERN_WARNING "Empty swap-file\n"); | |
2088 | error = -EINVAL; | |
2089 | goto bad_swap; | |
2090 | } | |
1da177e4 | 2091 | |
3bd0f0c7 SJ |
2092 | if (p->bdev) { |
2093 | if (blk_queue_nonrot(bdev_get_queue(p->bdev))) { | |
2094 | p->flags |= SWP_SOLIDSTATE; | |
2095 | p->cluster_next = 1 + (random32() % p->highest_bit); | |
2096 | } | |
33994466 | 2097 | if (discard_swap(p) == 0 && (swap_flags & SWAP_FLAG_DISCARD)) |
3bd0f0c7 | 2098 | p->flags |= SWP_DISCARDABLE; |
20137a49 | 2099 | } |
6a6ba831 | 2100 | |
fc0abb14 | 2101 | mutex_lock(&swapon_mutex); |
5d337b91 | 2102 | spin_lock(&swap_lock); |
78ecba08 HD |
2103 | if (swap_flags & SWAP_FLAG_PREFER) |
2104 | p->prio = | |
2105 | (swap_flags & SWAP_FLAG_PRIO_MASK) >> SWAP_FLAG_PRIO_SHIFT; | |
2106 | else | |
2107 | p->prio = --least_priority; | |
2108 | p->swap_map = swap_map; | |
22c6f8fd | 2109 | p->flags |= SWP_WRITEOK; |
1da177e4 LT |
2110 | nr_swap_pages += nr_good_pages; |
2111 | total_swap_pages += nr_good_pages; | |
53092a74 | 2112 | |
6eb396dc | 2113 | printk(KERN_INFO "Adding %uk swap on %s. " |
20137a49 | 2114 | "Priority:%d extents:%d across:%lluk %s%s\n", |
53092a74 | 2115 | nr_good_pages<<(PAGE_SHIFT-10), name, p->prio, |
6a6ba831 | 2116 | nr_extents, (unsigned long long)span<<(PAGE_SHIFT-10), |
20137a49 HD |
2117 | (p->flags & SWP_SOLIDSTATE) ? "SS" : "", |
2118 | (p->flags & SWP_DISCARDABLE) ? "D" : ""); | |
1da177e4 LT |
2119 | |
2120 | /* insert swap space into swap_list: */ | |
2121 | prev = -1; | |
efa90a98 HD |
2122 | for (i = swap_list.head; i >= 0; i = swap_info[i]->next) { |
2123 | if (p->prio >= swap_info[i]->prio) | |
1da177e4 | 2124 | break; |
1da177e4 LT |
2125 | prev = i; |
2126 | } | |
2127 | p->next = i; | |
efa90a98 HD |
2128 | if (prev < 0) |
2129 | swap_list.head = swap_list.next = type; | |
2130 | else | |
2131 | swap_info[prev]->next = type; | |
5d337b91 | 2132 | spin_unlock(&swap_lock); |
fc0abb14 | 2133 | mutex_unlock(&swapon_mutex); |
66d7dd51 KS |
2134 | atomic_inc(&proc_poll_event); |
2135 | wake_up_interruptible(&proc_poll_wait); | |
2136 | ||
1da177e4 LT |
2137 | error = 0; |
2138 | goto out; | |
2139 | bad_swap: | |
2140 | if (bdev) { | |
2141 | set_blocksize(bdev, p->old_block_size); | |
e525fd89 | 2142 | blkdev_put(bdev, FMODE_READ | FMODE_WRITE | FMODE_EXCL); |
1da177e4 | 2143 | } |
4cd3bb10 | 2144 | destroy_swap_extents(p); |
27a7faa0 | 2145 | swap_cgroup_swapoff(type); |
1da177e4 | 2146 | bad_swap_2: |
5d337b91 | 2147 | spin_lock(&swap_lock); |
1da177e4 | 2148 | p->swap_file = NULL; |
1da177e4 | 2149 | p->flags = 0; |
5d337b91 | 2150 | spin_unlock(&swap_lock); |
1da177e4 LT |
2151 | vfree(swap_map); |
2152 | if (swap_file) | |
2153 | filp_close(swap_file, NULL); | |
2154 | out: | |
2155 | if (page && !IS_ERR(page)) { | |
2156 | kunmap(page); | |
2157 | page_cache_release(page); | |
2158 | } | |
2159 | if (name) | |
2160 | putname(name); | |
2161 | if (did_down) { | |
2162 | if (!error) | |
2163 | inode->i_flags |= S_SWAPFILE; | |
1b1dcc1b | 2164 | mutex_unlock(&inode->i_mutex); |
1da177e4 LT |
2165 | } |
2166 | return error; | |
2167 | } | |
2168 | ||
2169 | void si_swapinfo(struct sysinfo *val) | |
2170 | { | |
efa90a98 | 2171 | unsigned int type; |
1da177e4 LT |
2172 | unsigned long nr_to_be_unused = 0; |
2173 | ||
5d337b91 | 2174 | spin_lock(&swap_lock); |
efa90a98 HD |
2175 | for (type = 0; type < nr_swapfiles; type++) { |
2176 | struct swap_info_struct *si = swap_info[type]; | |
2177 | ||
2178 | if ((si->flags & SWP_USED) && !(si->flags & SWP_WRITEOK)) | |
2179 | nr_to_be_unused += si->inuse_pages; | |
1da177e4 LT |
2180 | } |
2181 | val->freeswap = nr_swap_pages + nr_to_be_unused; | |
2182 | val->totalswap = total_swap_pages + nr_to_be_unused; | |
5d337b91 | 2183 | spin_unlock(&swap_lock); |
1da177e4 LT |
2184 | } |
2185 | ||
2186 | /* | |
2187 | * Verify that a swap entry is valid and increment its swap map count. | |
2188 | * | |
355cfa73 KH |
2189 | * Returns error code in following case. |
2190 | * - success -> 0 | |
2191 | * - swp_entry is invalid -> EINVAL | |
2192 | * - swp_entry is migration entry -> EINVAL | |
2193 | * - swap-cache reference is requested but there is already one. -> EEXIST | |
2194 | * - swap-cache reference is requested but the entry is not used. -> ENOENT | |
570a335b | 2195 | * - swap-mapped reference requested but needs continued swap count. -> ENOMEM |
1da177e4 | 2196 | */ |
8d69aaee | 2197 | static int __swap_duplicate(swp_entry_t entry, unsigned char usage) |
1da177e4 | 2198 | { |
73c34b6a | 2199 | struct swap_info_struct *p; |
1da177e4 | 2200 | unsigned long offset, type; |
8d69aaee HD |
2201 | unsigned char count; |
2202 | unsigned char has_cache; | |
253d553b | 2203 | int err = -EINVAL; |
1da177e4 | 2204 | |
a7420aa5 | 2205 | if (non_swap_entry(entry)) |
253d553b | 2206 | goto out; |
0697212a | 2207 | |
1da177e4 LT |
2208 | type = swp_type(entry); |
2209 | if (type >= nr_swapfiles) | |
2210 | goto bad_file; | |
efa90a98 | 2211 | p = swap_info[type]; |
1da177e4 LT |
2212 | offset = swp_offset(entry); |
2213 | ||
5d337b91 | 2214 | spin_lock(&swap_lock); |
355cfa73 KH |
2215 | if (unlikely(offset >= p->max)) |
2216 | goto unlock_out; | |
2217 | ||
253d553b HD |
2218 | count = p->swap_map[offset]; |
2219 | has_cache = count & SWAP_HAS_CACHE; | |
2220 | count &= ~SWAP_HAS_CACHE; | |
2221 | err = 0; | |
355cfa73 | 2222 | |
253d553b | 2223 | if (usage == SWAP_HAS_CACHE) { |
355cfa73 KH |
2224 | |
2225 | /* set SWAP_HAS_CACHE if there is no cache and entry is used */ | |
253d553b HD |
2226 | if (!has_cache && count) |
2227 | has_cache = SWAP_HAS_CACHE; | |
2228 | else if (has_cache) /* someone else added cache */ | |
2229 | err = -EEXIST; | |
2230 | else /* no users remaining */ | |
2231 | err = -ENOENT; | |
355cfa73 KH |
2232 | |
2233 | } else if (count || has_cache) { | |
253d553b | 2234 | |
570a335b HD |
2235 | if ((count & ~COUNT_CONTINUED) < SWAP_MAP_MAX) |
2236 | count += usage; | |
2237 | else if ((count & ~COUNT_CONTINUED) > SWAP_MAP_MAX) | |
253d553b | 2238 | err = -EINVAL; |
570a335b HD |
2239 | else if (swap_count_continued(p, offset, count)) |
2240 | count = COUNT_CONTINUED; | |
2241 | else | |
2242 | err = -ENOMEM; | |
355cfa73 | 2243 | } else |
253d553b HD |
2244 | err = -ENOENT; /* unused swap entry */ |
2245 | ||
2246 | p->swap_map[offset] = count | has_cache; | |
2247 | ||
355cfa73 | 2248 | unlock_out: |
5d337b91 | 2249 | spin_unlock(&swap_lock); |
1da177e4 | 2250 | out: |
253d553b | 2251 | return err; |
1da177e4 LT |
2252 | |
2253 | bad_file: | |
2254 | printk(KERN_ERR "swap_dup: %s%08lx\n", Bad_file, entry.val); | |
2255 | goto out; | |
2256 | } | |
253d553b | 2257 | |
aaa46865 HD |
2258 | /* |
2259 | * Help swapoff by noting that swap entry belongs to shmem/tmpfs | |
2260 | * (in which case its reference count is never incremented). | |
2261 | */ | |
2262 | void swap_shmem_alloc(swp_entry_t entry) | |
2263 | { | |
2264 | __swap_duplicate(entry, SWAP_MAP_SHMEM); | |
2265 | } | |
2266 | ||
355cfa73 | 2267 | /* |
08259d58 HD |
2268 | * Increase reference count of swap entry by 1. |
2269 | * Returns 0 for success, or -ENOMEM if a swap_count_continuation is required | |
2270 | * but could not be atomically allocated. Returns 0, just as if it succeeded, | |
2271 | * if __swap_duplicate() fails for another reason (-EINVAL or -ENOENT), which | |
2272 | * might occur if a page table entry has got corrupted. | |
355cfa73 | 2273 | */ |
570a335b | 2274 | int swap_duplicate(swp_entry_t entry) |
355cfa73 | 2275 | { |
570a335b HD |
2276 | int err = 0; |
2277 | ||
2278 | while (!err && __swap_duplicate(entry, 1) == -ENOMEM) | |
2279 | err = add_swap_count_continuation(entry, GFP_ATOMIC); | |
2280 | return err; | |
355cfa73 | 2281 | } |
1da177e4 | 2282 | |
cb4b86ba | 2283 | /* |
355cfa73 KH |
2284 | * @entry: swap entry for which we allocate swap cache. |
2285 | * | |
73c34b6a | 2286 | * Called when allocating swap cache for existing swap entry, |
355cfa73 KH |
2287 | * This can return error codes. Returns 0 at success. |
2288 | * -EBUSY means there is a swap cache. | |
2289 | * Note: return code is different from swap_duplicate(). | |
cb4b86ba KH |
2290 | */ |
2291 | int swapcache_prepare(swp_entry_t entry) | |
2292 | { | |
253d553b | 2293 | return __swap_duplicate(entry, SWAP_HAS_CACHE); |
cb4b86ba KH |
2294 | } |
2295 | ||
1da177e4 | 2296 | /* |
5d337b91 | 2297 | * swap_lock prevents swap_map being freed. Don't grab an extra |
1da177e4 LT |
2298 | * reference on the swaphandle, it doesn't matter if it becomes unused. |
2299 | */ | |
2300 | int valid_swaphandles(swp_entry_t entry, unsigned long *offset) | |
2301 | { | |
8952898b | 2302 | struct swap_info_struct *si; |
3f9e7949 | 2303 | int our_page_cluster = page_cluster; |
8952898b HD |
2304 | pgoff_t target, toff; |
2305 | pgoff_t base, end; | |
2306 | int nr_pages = 0; | |
1da177e4 | 2307 | |
3f9e7949 | 2308 | if (!our_page_cluster) /* no readahead */ |
1da177e4 | 2309 | return 0; |
8952898b | 2310 | |
efa90a98 | 2311 | si = swap_info[swp_type(entry)]; |
8952898b HD |
2312 | target = swp_offset(entry); |
2313 | base = (target >> our_page_cluster) << our_page_cluster; | |
2314 | end = base + (1 << our_page_cluster); | |
2315 | if (!base) /* first page is swap header */ | |
2316 | base++; | |
1da177e4 | 2317 | |
5d337b91 | 2318 | spin_lock(&swap_lock); |
8952898b HD |
2319 | if (end > si->max) /* don't go beyond end of map */ |
2320 | end = si->max; | |
2321 | ||
2322 | /* Count contiguous allocated slots above our target */ | |
2323 | for (toff = target; ++toff < end; nr_pages++) { | |
2324 | /* Don't read in free or bad pages */ | |
2325 | if (!si->swap_map[toff]) | |
2326 | break; | |
355cfa73 | 2327 | if (swap_count(si->swap_map[toff]) == SWAP_MAP_BAD) |
1da177e4 | 2328 | break; |
8952898b HD |
2329 | } |
2330 | /* Count contiguous allocated slots below our target */ | |
2331 | for (toff = target; --toff >= base; nr_pages++) { | |
1da177e4 | 2332 | /* Don't read in free or bad pages */ |
8952898b | 2333 | if (!si->swap_map[toff]) |
1da177e4 | 2334 | break; |
355cfa73 | 2335 | if (swap_count(si->swap_map[toff]) == SWAP_MAP_BAD) |
1da177e4 | 2336 | break; |
8952898b | 2337 | } |
5d337b91 | 2338 | spin_unlock(&swap_lock); |
8952898b HD |
2339 | |
2340 | /* | |
2341 | * Indicate starting offset, and return number of pages to get: | |
2342 | * if only 1, say 0, since there's then no readahead to be done. | |
2343 | */ | |
2344 | *offset = ++toff; | |
2345 | return nr_pages? ++nr_pages: 0; | |
1da177e4 | 2346 | } |
570a335b HD |
2347 | |
2348 | /* | |
2349 | * add_swap_count_continuation - called when a swap count is duplicated | |
2350 | * beyond SWAP_MAP_MAX, it allocates a new page and links that to the entry's | |
2351 | * page of the original vmalloc'ed swap_map, to hold the continuation count | |
2352 | * (for that entry and for its neighbouring PAGE_SIZE swap entries). Called | |
2353 | * again when count is duplicated beyond SWAP_MAP_MAX * SWAP_CONT_MAX, etc. | |
2354 | * | |
2355 | * These continuation pages are seldom referenced: the common paths all work | |
2356 | * on the original swap_map, only referring to a continuation page when the | |
2357 | * low "digit" of a count is incremented or decremented through SWAP_MAP_MAX. | |
2358 | * | |
2359 | * add_swap_count_continuation(, GFP_ATOMIC) can be called while holding | |
2360 | * page table locks; if it fails, add_swap_count_continuation(, GFP_KERNEL) | |
2361 | * can be called after dropping locks. | |
2362 | */ | |
2363 | int add_swap_count_continuation(swp_entry_t entry, gfp_t gfp_mask) | |
2364 | { | |
2365 | struct swap_info_struct *si; | |
2366 | struct page *head; | |
2367 | struct page *page; | |
2368 | struct page *list_page; | |
2369 | pgoff_t offset; | |
2370 | unsigned char count; | |
2371 | ||
2372 | /* | |
2373 | * When debugging, it's easier to use __GFP_ZERO here; but it's better | |
2374 | * for latency not to zero a page while GFP_ATOMIC and holding locks. | |
2375 | */ | |
2376 | page = alloc_page(gfp_mask | __GFP_HIGHMEM); | |
2377 | ||
2378 | si = swap_info_get(entry); | |
2379 | if (!si) { | |
2380 | /* | |
2381 | * An acceptable race has occurred since the failing | |
2382 | * __swap_duplicate(): the swap entry has been freed, | |
2383 | * perhaps even the whole swap_map cleared for swapoff. | |
2384 | */ | |
2385 | goto outer; | |
2386 | } | |
2387 | ||
2388 | offset = swp_offset(entry); | |
2389 | count = si->swap_map[offset] & ~SWAP_HAS_CACHE; | |
2390 | ||
2391 | if ((count & ~COUNT_CONTINUED) != SWAP_MAP_MAX) { | |
2392 | /* | |
2393 | * The higher the swap count, the more likely it is that tasks | |
2394 | * will race to add swap count continuation: we need to avoid | |
2395 | * over-provisioning. | |
2396 | */ | |
2397 | goto out; | |
2398 | } | |
2399 | ||
2400 | if (!page) { | |
2401 | spin_unlock(&swap_lock); | |
2402 | return -ENOMEM; | |
2403 | } | |
2404 | ||
2405 | /* | |
2406 | * We are fortunate that although vmalloc_to_page uses pte_offset_map, | |
2407 | * no architecture is using highmem pages for kernel pagetables: so it | |
2408 | * will not corrupt the GFP_ATOMIC caller's atomic pagetable kmaps. | |
2409 | */ | |
2410 | head = vmalloc_to_page(si->swap_map + offset); | |
2411 | offset &= ~PAGE_MASK; | |
2412 | ||
2413 | /* | |
2414 | * Page allocation does not initialize the page's lru field, | |
2415 | * but it does always reset its private field. | |
2416 | */ | |
2417 | if (!page_private(head)) { | |
2418 | BUG_ON(count & COUNT_CONTINUED); | |
2419 | INIT_LIST_HEAD(&head->lru); | |
2420 | set_page_private(head, SWP_CONTINUED); | |
2421 | si->flags |= SWP_CONTINUED; | |
2422 | } | |
2423 | ||
2424 | list_for_each_entry(list_page, &head->lru, lru) { | |
2425 | unsigned char *map; | |
2426 | ||
2427 | /* | |
2428 | * If the previous map said no continuation, but we've found | |
2429 | * a continuation page, free our allocation and use this one. | |
2430 | */ | |
2431 | if (!(count & COUNT_CONTINUED)) | |
2432 | goto out; | |
2433 | ||
2434 | map = kmap_atomic(list_page, KM_USER0) + offset; | |
2435 | count = *map; | |
2436 | kunmap_atomic(map, KM_USER0); | |
2437 | ||
2438 | /* | |
2439 | * If this continuation count now has some space in it, | |
2440 | * free our allocation and use this one. | |
2441 | */ | |
2442 | if ((count & ~COUNT_CONTINUED) != SWAP_CONT_MAX) | |
2443 | goto out; | |
2444 | } | |
2445 | ||
2446 | list_add_tail(&page->lru, &head->lru); | |
2447 | page = NULL; /* now it's attached, don't free it */ | |
2448 | out: | |
2449 | spin_unlock(&swap_lock); | |
2450 | outer: | |
2451 | if (page) | |
2452 | __free_page(page); | |
2453 | return 0; | |
2454 | } | |
2455 | ||
2456 | /* | |
2457 | * swap_count_continued - when the original swap_map count is incremented | |
2458 | * from SWAP_MAP_MAX, check if there is already a continuation page to carry | |
2459 | * into, carry if so, or else fail until a new continuation page is allocated; | |
2460 | * when the original swap_map count is decremented from 0 with continuation, | |
2461 | * borrow from the continuation and report whether it still holds more. | |
2462 | * Called while __swap_duplicate() or swap_entry_free() holds swap_lock. | |
2463 | */ | |
2464 | static bool swap_count_continued(struct swap_info_struct *si, | |
2465 | pgoff_t offset, unsigned char count) | |
2466 | { | |
2467 | struct page *head; | |
2468 | struct page *page; | |
2469 | unsigned char *map; | |
2470 | ||
2471 | head = vmalloc_to_page(si->swap_map + offset); | |
2472 | if (page_private(head) != SWP_CONTINUED) { | |
2473 | BUG_ON(count & COUNT_CONTINUED); | |
2474 | return false; /* need to add count continuation */ | |
2475 | } | |
2476 | ||
2477 | offset &= ~PAGE_MASK; | |
2478 | page = list_entry(head->lru.next, struct page, lru); | |
2479 | map = kmap_atomic(page, KM_USER0) + offset; | |
2480 | ||
2481 | if (count == SWAP_MAP_MAX) /* initial increment from swap_map */ | |
2482 | goto init_map; /* jump over SWAP_CONT_MAX checks */ | |
2483 | ||
2484 | if (count == (SWAP_MAP_MAX | COUNT_CONTINUED)) { /* incrementing */ | |
2485 | /* | |
2486 | * Think of how you add 1 to 999 | |
2487 | */ | |
2488 | while (*map == (SWAP_CONT_MAX | COUNT_CONTINUED)) { | |
2489 | kunmap_atomic(map, KM_USER0); | |
2490 | page = list_entry(page->lru.next, struct page, lru); | |
2491 | BUG_ON(page == head); | |
2492 | map = kmap_atomic(page, KM_USER0) + offset; | |
2493 | } | |
2494 | if (*map == SWAP_CONT_MAX) { | |
2495 | kunmap_atomic(map, KM_USER0); | |
2496 | page = list_entry(page->lru.next, struct page, lru); | |
2497 | if (page == head) | |
2498 | return false; /* add count continuation */ | |
2499 | map = kmap_atomic(page, KM_USER0) + offset; | |
2500 | init_map: *map = 0; /* we didn't zero the page */ | |
2501 | } | |
2502 | *map += 1; | |
2503 | kunmap_atomic(map, KM_USER0); | |
2504 | page = list_entry(page->lru.prev, struct page, lru); | |
2505 | while (page != head) { | |
2506 | map = kmap_atomic(page, KM_USER0) + offset; | |
2507 | *map = COUNT_CONTINUED; | |
2508 | kunmap_atomic(map, KM_USER0); | |
2509 | page = list_entry(page->lru.prev, struct page, lru); | |
2510 | } | |
2511 | return true; /* incremented */ | |
2512 | ||
2513 | } else { /* decrementing */ | |
2514 | /* | |
2515 | * Think of how you subtract 1 from 1000 | |
2516 | */ | |
2517 | BUG_ON(count != COUNT_CONTINUED); | |
2518 | while (*map == COUNT_CONTINUED) { | |
2519 | kunmap_atomic(map, KM_USER0); | |
2520 | page = list_entry(page->lru.next, struct page, lru); | |
2521 | BUG_ON(page == head); | |
2522 | map = kmap_atomic(page, KM_USER0) + offset; | |
2523 | } | |
2524 | BUG_ON(*map == 0); | |
2525 | *map -= 1; | |
2526 | if (*map == 0) | |
2527 | count = 0; | |
2528 | kunmap_atomic(map, KM_USER0); | |
2529 | page = list_entry(page->lru.prev, struct page, lru); | |
2530 | while (page != head) { | |
2531 | map = kmap_atomic(page, KM_USER0) + offset; | |
2532 | *map = SWAP_CONT_MAX | count; | |
2533 | count = COUNT_CONTINUED; | |
2534 | kunmap_atomic(map, KM_USER0); | |
2535 | page = list_entry(page->lru.prev, struct page, lru); | |
2536 | } | |
2537 | return count == COUNT_CONTINUED; | |
2538 | } | |
2539 | } | |
2540 | ||
2541 | /* | |
2542 | * free_swap_count_continuations - swapoff free all the continuation pages | |
2543 | * appended to the swap_map, after swap_map is quiesced, before vfree'ing it. | |
2544 | */ | |
2545 | static void free_swap_count_continuations(struct swap_info_struct *si) | |
2546 | { | |
2547 | pgoff_t offset; | |
2548 | ||
2549 | for (offset = 0; offset < si->max; offset += PAGE_SIZE) { | |
2550 | struct page *head; | |
2551 | head = vmalloc_to_page(si->swap_map + offset); | |
2552 | if (page_private(head)) { | |
2553 | struct list_head *this, *next; | |
2554 | list_for_each_safe(this, next, &head->lru) { | |
2555 | struct page *page; | |
2556 | page = list_entry(this, struct page, lru); | |
2557 | list_del(this); | |
2558 | __free_page(page); | |
2559 | } | |
2560 | } | |
2561 | } | |
2562 | } |