Commit | Line | Data |
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457c8996 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
1da177e4 LT |
2 | /* |
3 | * linux/mm/swapfile.c | |
4 | * | |
5 | * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds | |
6 | * Swap reorganised 29.12.95, Stephen Tweedie | |
7 | */ | |
8 | ||
c97ab271 | 9 | #include <linux/blkdev.h> |
1da177e4 | 10 | #include <linux/mm.h> |
6e84f315 | 11 | #include <linux/sched/mm.h> |
29930025 | 12 | #include <linux/sched/task.h> |
1da177e4 LT |
13 | #include <linux/hugetlb.h> |
14 | #include <linux/mman.h> | |
15 | #include <linux/slab.h> | |
16 | #include <linux/kernel_stat.h> | |
17 | #include <linux/swap.h> | |
18 | #include <linux/vmalloc.h> | |
19 | #include <linux/pagemap.h> | |
20 | #include <linux/namei.h> | |
072441e2 | 21 | #include <linux/shmem_fs.h> |
e41d12f5 | 22 | #include <linux/blk-cgroup.h> |
20137a49 | 23 | #include <linux/random.h> |
1da177e4 LT |
24 | #include <linux/writeback.h> |
25 | #include <linux/proc_fs.h> | |
26 | #include <linux/seq_file.h> | |
27 | #include <linux/init.h> | |
5ad64688 | 28 | #include <linux/ksm.h> |
1da177e4 LT |
29 | #include <linux/rmap.h> |
30 | #include <linux/security.h> | |
31 | #include <linux/backing-dev.h> | |
fc0abb14 | 32 | #include <linux/mutex.h> |
c59ede7b | 33 | #include <linux/capability.h> |
1da177e4 | 34 | #include <linux/syscalls.h> |
8a9f3ccd | 35 | #include <linux/memcontrol.h> |
66d7dd51 | 36 | #include <linux/poll.h> |
72788c38 | 37 | #include <linux/oom.h> |
38b5faf4 | 38 | #include <linux/swapfile.h> |
f981c595 | 39 | #include <linux/export.h> |
67afa38e | 40 | #include <linux/swap_slots.h> |
155b5f88 | 41 | #include <linux/sort.h> |
63d8620e | 42 | #include <linux/completion.h> |
07f44ac3 | 43 | #include <linux/suspend.h> |
42c06a0e | 44 | #include <linux/zswap.h> |
8b7787a5 | 45 | #include <linux/plist.h> |
1da177e4 | 46 | |
1da177e4 LT |
47 | #include <asm/tlbflush.h> |
48 | #include <linux/swapops.h> | |
5d1ea48b | 49 | #include <linux/swap_cgroup.h> |
00cde042 | 50 | #include "internal.h" |
014bb1de | 51 | #include "swap.h" |
1da177e4 | 52 | |
570a335b HD |
53 | static bool swap_count_continued(struct swap_info_struct *, pgoff_t, |
54 | unsigned char); | |
55 | static void free_swap_count_continuations(struct swap_info_struct *); | |
56 | ||
633423a0 | 57 | static DEFINE_SPINLOCK(swap_lock); |
7c363b8c | 58 | static unsigned int nr_swapfiles; |
ec8acf20 | 59 | atomic_long_t nr_swap_pages; |
fb0fec50 CW |
60 | /* |
61 | * Some modules use swappable objects and may try to swap them out under | |
62 | * memory pressure (via the shrinker). Before doing so, they may wish to | |
63 | * check to see if any swap space is available. | |
64 | */ | |
65 | EXPORT_SYMBOL_GPL(nr_swap_pages); | |
ec8acf20 | 66 | /* protected with swap_lock. reading in vm_swap_full() doesn't need lock */ |
1da177e4 | 67 | long total_swap_pages; |
a2468cc9 | 68 | static int least_priority = -1; |
be45a490 | 69 | unsigned long swapfile_maximum_size; |
5154e607 PX |
70 | #ifdef CONFIG_MIGRATION |
71 | bool swap_migration_ad_supported; | |
72 | #endif /* CONFIG_MIGRATION */ | |
1da177e4 | 73 | |
1da177e4 LT |
74 | static const char Bad_file[] = "Bad swap file entry "; |
75 | static const char Unused_file[] = "Unused swap file entry "; | |
76 | static const char Bad_offset[] = "Bad swap offset entry "; | |
77 | static const char Unused_offset[] = "Unused swap offset entry "; | |
78 | ||
adfab836 DS |
79 | /* |
80 | * all active swap_info_structs | |
81 | * protected with swap_lock, and ordered by priority. | |
82 | */ | |
633423a0 | 83 | static PLIST_HEAD(swap_active_head); |
18ab4d4c DS |
84 | |
85 | /* | |
86 | * all available (active, not full) swap_info_structs | |
87 | * protected with swap_avail_lock, ordered by priority. | |
e2e3fdc7 | 88 | * This is used by folio_alloc_swap() instead of swap_active_head |
18ab4d4c | 89 | * because swap_active_head includes all swap_info_structs, |
e2e3fdc7 | 90 | * but folio_alloc_swap() doesn't need to look at full ones. |
18ab4d4c DS |
91 | * This uses its own lock instead of swap_lock because when a |
92 | * swap_info_struct changes between not-full/full, it needs to | |
93 | * add/remove itself to/from this list, but the swap_info_struct->lock | |
94 | * is held and the locking order requires swap_lock to be taken | |
95 | * before any swap_info_struct->lock. | |
96 | */ | |
bfc6b1ca | 97 | static struct plist_head *swap_avail_heads; |
18ab4d4c | 98 | static DEFINE_SPINLOCK(swap_avail_lock); |
1da177e4 | 99 | |
42c06a0e | 100 | static struct swap_info_struct *swap_info[MAX_SWAPFILES]; |
1da177e4 | 101 | |
fc0abb14 | 102 | static DEFINE_MUTEX(swapon_mutex); |
1da177e4 | 103 | |
66d7dd51 KS |
104 | static DECLARE_WAIT_QUEUE_HEAD(proc_poll_wait); |
105 | /* Activity counter to indicate that a swapon or swapoff has occurred */ | |
106 | static atomic_t proc_poll_event = ATOMIC_INIT(0); | |
107 | ||
81a0298b HY |
108 | atomic_t nr_rotate_swap = ATOMIC_INIT(0); |
109 | ||
c10d38cc DJ |
110 | static struct swap_info_struct *swap_type_to_swap_info(int type) |
111 | { | |
a4b45114 | 112 | if (type >= MAX_SWAPFILES) |
c10d38cc DJ |
113 | return NULL; |
114 | ||
a4b45114 | 115 | return READ_ONCE(swap_info[type]); /* rcu_dereference() */ |
c10d38cc DJ |
116 | } |
117 | ||
8d69aaee | 118 | static inline unsigned char swap_count(unsigned char ent) |
355cfa73 | 119 | { |
955c97f0 | 120 | return ent & ~SWAP_HAS_CACHE; /* may include COUNT_CONTINUED flag */ |
355cfa73 KH |
121 | } |
122 | ||
bcd49e86 HY |
123 | /* Reclaim the swap entry anyway if possible */ |
124 | #define TTRS_ANYWAY 0x1 | |
125 | /* | |
126 | * Reclaim the swap entry if there are no more mappings of the | |
127 | * corresponding page | |
128 | */ | |
129 | #define TTRS_UNMAPPED 0x2 | |
130 | /* Reclaim the swap entry if swap is getting full*/ | |
131 | #define TTRS_FULL 0x4 | |
132 | ||
a62fb92a RR |
133 | /* |
134 | * returns number of pages in the folio that backs the swap entry. If positive, | |
135 | * the folio was reclaimed. If negative, the folio was not reclaimed. If 0, no | |
136 | * folio was associated with the swap entry. | |
137 | */ | |
bcd49e86 HY |
138 | static int __try_to_reclaim_swap(struct swap_info_struct *si, |
139 | unsigned long offset, unsigned long flags) | |
c9e44410 | 140 | { |
efa90a98 | 141 | swp_entry_t entry = swp_entry(si->type, offset); |
2c3f6194 | 142 | struct folio *folio; |
c9e44410 KH |
143 | int ret = 0; |
144 | ||
7aad25b4 | 145 | folio = filemap_get_folio(swap_address_space(entry), swap_cache_index(entry)); |
66dabbb6 | 146 | if (IS_ERR(folio)) |
c9e44410 KH |
147 | return 0; |
148 | /* | |
bcd49e86 | 149 | * When this function is called from scan_swap_map_slots() and it's |
2c3f6194 | 150 | * called by vmscan.c at reclaiming folios. So we hold a folio lock |
bcd49e86 | 151 | * here. We have to use trylock for avoiding deadlock. This is a special |
2c3f6194 | 152 | * case and you should use folio_free_swap() with explicit folio_lock() |
c9e44410 KH |
153 | * in usual operations. |
154 | */ | |
2c3f6194 | 155 | if (folio_trylock(folio)) { |
bcd49e86 | 156 | if ((flags & TTRS_ANYWAY) || |
2c3f6194 | 157 | ((flags & TTRS_UNMAPPED) && !folio_mapped(folio)) || |
9202d527 | 158 | ((flags & TTRS_FULL) && mem_cgroup_swap_full(folio))) |
2c3f6194 MWO |
159 | ret = folio_free_swap(folio); |
160 | folio_unlock(folio); | |
c9e44410 | 161 | } |
a62fb92a | 162 | ret = ret ? folio_nr_pages(folio) : -folio_nr_pages(folio); |
2c3f6194 | 163 | folio_put(folio); |
c9e44410 KH |
164 | return ret; |
165 | } | |
355cfa73 | 166 | |
4efaceb1 AL |
167 | static inline struct swap_extent *first_se(struct swap_info_struct *sis) |
168 | { | |
169 | struct rb_node *rb = rb_first(&sis->swap_extent_root); | |
170 | return rb_entry(rb, struct swap_extent, rb_node); | |
171 | } | |
172 | ||
173 | static inline struct swap_extent *next_se(struct swap_extent *se) | |
174 | { | |
175 | struct rb_node *rb = rb_next(&se->rb_node); | |
176 | return rb ? rb_entry(rb, struct swap_extent, rb_node) : NULL; | |
177 | } | |
178 | ||
6a6ba831 HD |
179 | /* |
180 | * swapon tell device that all the old swap contents can be discarded, | |
181 | * to allow the swap device to optimize its wear-levelling. | |
182 | */ | |
183 | static int discard_swap(struct swap_info_struct *si) | |
184 | { | |
185 | struct swap_extent *se; | |
9625a5f2 HD |
186 | sector_t start_block; |
187 | sector_t nr_blocks; | |
6a6ba831 HD |
188 | int err = 0; |
189 | ||
9625a5f2 | 190 | /* Do not discard the swap header page! */ |
4efaceb1 | 191 | se = first_se(si); |
9625a5f2 HD |
192 | start_block = (se->start_block + 1) << (PAGE_SHIFT - 9); |
193 | nr_blocks = ((sector_t)se->nr_pages - 1) << (PAGE_SHIFT - 9); | |
194 | if (nr_blocks) { | |
195 | err = blkdev_issue_discard(si->bdev, start_block, | |
44abff2c | 196 | nr_blocks, GFP_KERNEL); |
9625a5f2 HD |
197 | if (err) |
198 | return err; | |
199 | cond_resched(); | |
200 | } | |
6a6ba831 | 201 | |
4efaceb1 | 202 | for (se = next_se(se); se; se = next_se(se)) { |
9625a5f2 HD |
203 | start_block = se->start_block << (PAGE_SHIFT - 9); |
204 | nr_blocks = (sector_t)se->nr_pages << (PAGE_SHIFT - 9); | |
6a6ba831 HD |
205 | |
206 | err = blkdev_issue_discard(si->bdev, start_block, | |
44abff2c | 207 | nr_blocks, GFP_KERNEL); |
6a6ba831 HD |
208 | if (err) |
209 | break; | |
210 | ||
211 | cond_resched(); | |
212 | } | |
213 | return err; /* That will often be -EOPNOTSUPP */ | |
214 | } | |
215 | ||
4efaceb1 AL |
216 | static struct swap_extent * |
217 | offset_to_swap_extent(struct swap_info_struct *sis, unsigned long offset) | |
218 | { | |
219 | struct swap_extent *se; | |
220 | struct rb_node *rb; | |
221 | ||
222 | rb = sis->swap_extent_root.rb_node; | |
223 | while (rb) { | |
224 | se = rb_entry(rb, struct swap_extent, rb_node); | |
225 | if (offset < se->start_page) | |
226 | rb = rb->rb_left; | |
227 | else if (offset >= se->start_page + se->nr_pages) | |
228 | rb = rb->rb_right; | |
229 | else | |
230 | return se; | |
231 | } | |
232 | /* It *must* be present */ | |
233 | BUG(); | |
234 | } | |
235 | ||
3a61e6f6 | 236 | sector_t swap_folio_sector(struct folio *folio) |
caf6912f | 237 | { |
3a61e6f6 | 238 | struct swap_info_struct *sis = swp_swap_info(folio->swap); |
caf6912f JA |
239 | struct swap_extent *se; |
240 | sector_t sector; | |
241 | pgoff_t offset; | |
242 | ||
3a61e6f6 | 243 | offset = swp_offset(folio->swap); |
caf6912f JA |
244 | se = offset_to_swap_extent(sis, offset); |
245 | sector = se->start_block + (offset - se->start_page); | |
246 | return sector << (PAGE_SHIFT - 9); | |
247 | } | |
248 | ||
7992fde7 HD |
249 | /* |
250 | * swap allocation tell device that a cluster of swap can now be discarded, | |
251 | * to allow the swap device to optimize its wear-levelling. | |
252 | */ | |
253 | static void discard_swap_cluster(struct swap_info_struct *si, | |
254 | pgoff_t start_page, pgoff_t nr_pages) | |
255 | { | |
4efaceb1 | 256 | struct swap_extent *se = offset_to_swap_extent(si, start_page); |
7992fde7 HD |
257 | |
258 | while (nr_pages) { | |
4efaceb1 AL |
259 | pgoff_t offset = start_page - se->start_page; |
260 | sector_t start_block = se->start_block + offset; | |
261 | sector_t nr_blocks = se->nr_pages - offset; | |
262 | ||
263 | if (nr_blocks > nr_pages) | |
264 | nr_blocks = nr_pages; | |
265 | start_page += nr_blocks; | |
266 | nr_pages -= nr_blocks; | |
267 | ||
268 | start_block <<= PAGE_SHIFT - 9; | |
269 | nr_blocks <<= PAGE_SHIFT - 9; | |
270 | if (blkdev_issue_discard(si->bdev, start_block, | |
44abff2c | 271 | nr_blocks, GFP_NOIO)) |
4efaceb1 | 272 | break; |
7992fde7 | 273 | |
4efaceb1 | 274 | se = next_se(se); |
7992fde7 HD |
275 | } |
276 | } | |
277 | ||
38d8b4e6 HY |
278 | #ifdef CONFIG_THP_SWAP |
279 | #define SWAPFILE_CLUSTER HPAGE_PMD_NR | |
a448f2d0 | 280 | |
9faaa0f8 | 281 | #define swap_entry_order(order) (order) |
38d8b4e6 | 282 | #else |
048c27fd | 283 | #define SWAPFILE_CLUSTER 256 |
a448f2d0 HY |
284 | |
285 | /* | |
9faaa0f8 | 286 | * Define swap_entry_order() as constant to let compiler to optimize |
a448f2d0 HY |
287 | * out some code if !CONFIG_THP_SWAP |
288 | */ | |
9faaa0f8 | 289 | #define swap_entry_order(order) 0 |
38d8b4e6 | 290 | #endif |
048c27fd HD |
291 | #define LATENCY_LIMIT 256 |
292 | ||
2a8f9449 SL |
293 | static inline void cluster_set_flag(struct swap_cluster_info *info, |
294 | unsigned int flag) | |
295 | { | |
296 | info->flags = flag; | |
297 | } | |
298 | ||
299 | static inline unsigned int cluster_count(struct swap_cluster_info *info) | |
300 | { | |
301 | return info->data; | |
302 | } | |
303 | ||
304 | static inline void cluster_set_count(struct swap_cluster_info *info, | |
305 | unsigned int c) | |
306 | { | |
307 | info->data = c; | |
308 | } | |
309 | ||
310 | static inline void cluster_set_count_flag(struct swap_cluster_info *info, | |
311 | unsigned int c, unsigned int f) | |
312 | { | |
313 | info->flags = f; | |
314 | info->data = c; | |
315 | } | |
316 | ||
317 | static inline unsigned int cluster_next(struct swap_cluster_info *info) | |
318 | { | |
319 | return info->data; | |
320 | } | |
321 | ||
322 | static inline void cluster_set_next(struct swap_cluster_info *info, | |
323 | unsigned int n) | |
324 | { | |
325 | info->data = n; | |
326 | } | |
327 | ||
328 | static inline void cluster_set_next_flag(struct swap_cluster_info *info, | |
329 | unsigned int n, unsigned int f) | |
330 | { | |
331 | info->flags = f; | |
332 | info->data = n; | |
333 | } | |
334 | ||
335 | static inline bool cluster_is_free(struct swap_cluster_info *info) | |
336 | { | |
337 | return info->flags & CLUSTER_FLAG_FREE; | |
338 | } | |
339 | ||
340 | static inline bool cluster_is_null(struct swap_cluster_info *info) | |
341 | { | |
342 | return info->flags & CLUSTER_FLAG_NEXT_NULL; | |
343 | } | |
344 | ||
345 | static inline void cluster_set_null(struct swap_cluster_info *info) | |
346 | { | |
347 | info->flags = CLUSTER_FLAG_NEXT_NULL; | |
348 | info->data = 0; | |
349 | } | |
350 | ||
235b6217 HY |
351 | static inline struct swap_cluster_info *lock_cluster(struct swap_info_struct *si, |
352 | unsigned long offset) | |
353 | { | |
354 | struct swap_cluster_info *ci; | |
355 | ||
356 | ci = si->cluster_info; | |
357 | if (ci) { | |
358 | ci += offset / SWAPFILE_CLUSTER; | |
359 | spin_lock(&ci->lock); | |
360 | } | |
361 | return ci; | |
362 | } | |
363 | ||
364 | static inline void unlock_cluster(struct swap_cluster_info *ci) | |
365 | { | |
366 | if (ci) | |
367 | spin_unlock(&ci->lock); | |
368 | } | |
369 | ||
59d98bf3 HY |
370 | /* |
371 | * Determine the locking method in use for this device. Return | |
372 | * swap_cluster_info if SSD-style cluster-based locking is in place. | |
373 | */ | |
235b6217 | 374 | static inline struct swap_cluster_info *lock_cluster_or_swap_info( |
59d98bf3 | 375 | struct swap_info_struct *si, unsigned long offset) |
235b6217 HY |
376 | { |
377 | struct swap_cluster_info *ci; | |
378 | ||
59d98bf3 | 379 | /* Try to use fine-grained SSD-style locking if available: */ |
235b6217 | 380 | ci = lock_cluster(si, offset); |
59d98bf3 | 381 | /* Otherwise, fall back to traditional, coarse locking: */ |
235b6217 HY |
382 | if (!ci) |
383 | spin_lock(&si->lock); | |
384 | ||
385 | return ci; | |
386 | } | |
387 | ||
388 | static inline void unlock_cluster_or_swap_info(struct swap_info_struct *si, | |
389 | struct swap_cluster_info *ci) | |
390 | { | |
391 | if (ci) | |
392 | unlock_cluster(ci); | |
393 | else | |
394 | spin_unlock(&si->lock); | |
395 | } | |
396 | ||
6b534915 HY |
397 | static inline bool cluster_list_empty(struct swap_cluster_list *list) |
398 | { | |
399 | return cluster_is_null(&list->head); | |
400 | } | |
401 | ||
402 | static inline unsigned int cluster_list_first(struct swap_cluster_list *list) | |
403 | { | |
404 | return cluster_next(&list->head); | |
405 | } | |
406 | ||
407 | static void cluster_list_init(struct swap_cluster_list *list) | |
408 | { | |
409 | cluster_set_null(&list->head); | |
410 | cluster_set_null(&list->tail); | |
411 | } | |
412 | ||
413 | static void cluster_list_add_tail(struct swap_cluster_list *list, | |
414 | struct swap_cluster_info *ci, | |
415 | unsigned int idx) | |
416 | { | |
417 | if (cluster_list_empty(list)) { | |
418 | cluster_set_next_flag(&list->head, idx, 0); | |
419 | cluster_set_next_flag(&list->tail, idx, 0); | |
420 | } else { | |
235b6217 | 421 | struct swap_cluster_info *ci_tail; |
6b534915 HY |
422 | unsigned int tail = cluster_next(&list->tail); |
423 | ||
235b6217 HY |
424 | /* |
425 | * Nested cluster lock, but both cluster locks are | |
426 | * only acquired when we held swap_info_struct->lock | |
427 | */ | |
428 | ci_tail = ci + tail; | |
429 | spin_lock_nested(&ci_tail->lock, SINGLE_DEPTH_NESTING); | |
430 | cluster_set_next(ci_tail, idx); | |
0ef017d1 | 431 | spin_unlock(&ci_tail->lock); |
6b534915 HY |
432 | cluster_set_next_flag(&list->tail, idx, 0); |
433 | } | |
434 | } | |
435 | ||
436 | static unsigned int cluster_list_del_first(struct swap_cluster_list *list, | |
437 | struct swap_cluster_info *ci) | |
438 | { | |
439 | unsigned int idx; | |
440 | ||
441 | idx = cluster_next(&list->head); | |
442 | if (cluster_next(&list->tail) == idx) { | |
443 | cluster_set_null(&list->head); | |
444 | cluster_set_null(&list->tail); | |
445 | } else | |
446 | cluster_set_next_flag(&list->head, | |
447 | cluster_next(&ci[idx]), 0); | |
448 | ||
449 | return idx; | |
450 | } | |
451 | ||
815c2c54 SL |
452 | /* Add a cluster to discard list and schedule it to do discard */ |
453 | static void swap_cluster_schedule_discard(struct swap_info_struct *si, | |
454 | unsigned int idx) | |
455 | { | |
456 | /* | |
bb243f7d | 457 | * If scan_swap_map_slots() can't find a free cluster, it will check |
815c2c54 | 458 | * si->swap_map directly. To make sure the discarding cluster isn't |
bb243f7d ML |
459 | * taken by scan_swap_map_slots(), mark the swap entries bad (occupied). |
460 | * It will be cleared after discard | |
815c2c54 SL |
461 | */ |
462 | memset(si->swap_map + idx * SWAPFILE_CLUSTER, | |
463 | SWAP_MAP_BAD, SWAPFILE_CLUSTER); | |
464 | ||
6b534915 | 465 | cluster_list_add_tail(&si->discard_clusters, si->cluster_info, idx); |
815c2c54 SL |
466 | |
467 | schedule_work(&si->discard_work); | |
468 | } | |
469 | ||
38d8b4e6 HY |
470 | static void __free_cluster(struct swap_info_struct *si, unsigned long idx) |
471 | { | |
472 | struct swap_cluster_info *ci = si->cluster_info; | |
473 | ||
474 | cluster_set_flag(ci + idx, CLUSTER_FLAG_FREE); | |
475 | cluster_list_add_tail(&si->free_clusters, ci, idx); | |
476 | } | |
477 | ||
815c2c54 SL |
478 | /* |
479 | * Doing discard actually. After a cluster discard is finished, the cluster | |
480 | * will be added to free cluster list. caller should hold si->lock. | |
481 | */ | |
482 | static void swap_do_scheduled_discard(struct swap_info_struct *si) | |
483 | { | |
235b6217 | 484 | struct swap_cluster_info *info, *ci; |
815c2c54 SL |
485 | unsigned int idx; |
486 | ||
487 | info = si->cluster_info; | |
488 | ||
6b534915 HY |
489 | while (!cluster_list_empty(&si->discard_clusters)) { |
490 | idx = cluster_list_del_first(&si->discard_clusters, info); | |
815c2c54 SL |
491 | spin_unlock(&si->lock); |
492 | ||
493 | discard_swap_cluster(si, idx * SWAPFILE_CLUSTER, | |
494 | SWAPFILE_CLUSTER); | |
495 | ||
496 | spin_lock(&si->lock); | |
235b6217 | 497 | ci = lock_cluster(si, idx * SWAPFILE_CLUSTER); |
38d8b4e6 | 498 | __free_cluster(si, idx); |
815c2c54 SL |
499 | memset(si->swap_map + idx * SWAPFILE_CLUSTER, |
500 | 0, SWAPFILE_CLUSTER); | |
235b6217 | 501 | unlock_cluster(ci); |
815c2c54 SL |
502 | } |
503 | } | |
504 | ||
505 | static void swap_discard_work(struct work_struct *work) | |
506 | { | |
507 | struct swap_info_struct *si; | |
508 | ||
509 | si = container_of(work, struct swap_info_struct, discard_work); | |
510 | ||
511 | spin_lock(&si->lock); | |
512 | swap_do_scheduled_discard(si); | |
513 | spin_unlock(&si->lock); | |
514 | } | |
515 | ||
63d8620e ML |
516 | static void swap_users_ref_free(struct percpu_ref *ref) |
517 | { | |
518 | struct swap_info_struct *si; | |
519 | ||
520 | si = container_of(ref, struct swap_info_struct, users); | |
521 | complete(&si->comp); | |
522 | } | |
523 | ||
38d8b4e6 HY |
524 | static void alloc_cluster(struct swap_info_struct *si, unsigned long idx) |
525 | { | |
526 | struct swap_cluster_info *ci = si->cluster_info; | |
527 | ||
528 | VM_BUG_ON(cluster_list_first(&si->free_clusters) != idx); | |
529 | cluster_list_del_first(&si->free_clusters, ci); | |
530 | cluster_set_count_flag(ci + idx, 0, 0); | |
531 | } | |
532 | ||
533 | static void free_cluster(struct swap_info_struct *si, unsigned long idx) | |
534 | { | |
535 | struct swap_cluster_info *ci = si->cluster_info + idx; | |
536 | ||
537 | VM_BUG_ON(cluster_count(ci) != 0); | |
538 | /* | |
539 | * If the swap is discardable, prepare discard the cluster | |
540 | * instead of free it immediately. The cluster will be freed | |
541 | * after discard. | |
542 | */ | |
543 | if ((si->flags & (SWP_WRITEOK | SWP_PAGE_DISCARD)) == | |
544 | (SWP_WRITEOK | SWP_PAGE_DISCARD)) { | |
545 | swap_cluster_schedule_discard(si, idx); | |
546 | return; | |
547 | } | |
548 | ||
549 | __free_cluster(si, idx); | |
550 | } | |
551 | ||
2a8f9449 SL |
552 | /* |
553 | * The cluster corresponding to page_nr will be used. The cluster will be | |
845982eb RR |
554 | * removed from free cluster list and its usage counter will be increased by |
555 | * count. | |
2a8f9449 | 556 | */ |
845982eb RR |
557 | static void add_cluster_info_page(struct swap_info_struct *p, |
558 | struct swap_cluster_info *cluster_info, unsigned long page_nr, | |
559 | unsigned long count) | |
2a8f9449 SL |
560 | { |
561 | unsigned long idx = page_nr / SWAPFILE_CLUSTER; | |
562 | ||
563 | if (!cluster_info) | |
564 | return; | |
38d8b4e6 HY |
565 | if (cluster_is_free(&cluster_info[idx])) |
566 | alloc_cluster(p, idx); | |
2a8f9449 | 567 | |
845982eb | 568 | VM_BUG_ON(cluster_count(&cluster_info[idx]) + count > SWAPFILE_CLUSTER); |
2a8f9449 | 569 | cluster_set_count(&cluster_info[idx], |
845982eb RR |
570 | cluster_count(&cluster_info[idx]) + count); |
571 | } | |
572 | ||
573 | /* | |
574 | * The cluster corresponding to page_nr will be used. The cluster will be | |
575 | * removed from free cluster list and its usage counter will be increased by 1. | |
576 | */ | |
577 | static void inc_cluster_info_page(struct swap_info_struct *p, | |
578 | struct swap_cluster_info *cluster_info, unsigned long page_nr) | |
579 | { | |
580 | add_cluster_info_page(p, cluster_info, page_nr, 1); | |
2a8f9449 SL |
581 | } |
582 | ||
583 | /* | |
584 | * The cluster corresponding to page_nr decreases one usage. If the usage | |
585 | * counter becomes 0, which means no page in the cluster is in using, we can | |
586 | * optionally discard the cluster and add it to free cluster list. | |
587 | */ | |
588 | static void dec_cluster_info_page(struct swap_info_struct *p, | |
589 | struct swap_cluster_info *cluster_info, unsigned long page_nr) | |
590 | { | |
591 | unsigned long idx = page_nr / SWAPFILE_CLUSTER; | |
592 | ||
593 | if (!cluster_info) | |
594 | return; | |
595 | ||
596 | VM_BUG_ON(cluster_count(&cluster_info[idx]) == 0); | |
597 | cluster_set_count(&cluster_info[idx], | |
598 | cluster_count(&cluster_info[idx]) - 1); | |
599 | ||
38d8b4e6 HY |
600 | if (cluster_count(&cluster_info[idx]) == 0) |
601 | free_cluster(p, idx); | |
2a8f9449 SL |
602 | } |
603 | ||
604 | /* | |
bb243f7d | 605 | * It's possible scan_swap_map_slots() uses a free cluster in the middle of free |
2a8f9449 SL |
606 | * cluster list. Avoiding such abuse to avoid list corruption. |
607 | */ | |
ebc2a1a6 SL |
608 | static bool |
609 | scan_swap_map_ssd_cluster_conflict(struct swap_info_struct *si, | |
845982eb | 610 | unsigned long offset, int order) |
2a8f9449 | 611 | { |
ebc2a1a6 SL |
612 | struct percpu_cluster *percpu_cluster; |
613 | bool conflict; | |
614 | ||
2a8f9449 | 615 | offset /= SWAPFILE_CLUSTER; |
6b534915 HY |
616 | conflict = !cluster_list_empty(&si->free_clusters) && |
617 | offset != cluster_list_first(&si->free_clusters) && | |
2a8f9449 | 618 | cluster_is_free(&si->cluster_info[offset]); |
ebc2a1a6 SL |
619 | |
620 | if (!conflict) | |
621 | return false; | |
622 | ||
623 | percpu_cluster = this_cpu_ptr(si->percpu_cluster); | |
845982eb RR |
624 | percpu_cluster->next[order] = SWAP_NEXT_INVALID; |
625 | return true; | |
626 | } | |
627 | ||
628 | static inline bool swap_range_empty(char *swap_map, unsigned int start, | |
629 | unsigned int nr_pages) | |
630 | { | |
631 | unsigned int i; | |
632 | ||
633 | for (i = 0; i < nr_pages; i++) { | |
634 | if (swap_map[start + i]) | |
635 | return false; | |
636 | } | |
637 | ||
ebc2a1a6 SL |
638 | return true; |
639 | } | |
640 | ||
641 | /* | |
845982eb RR |
642 | * Try to get swap entries with specified order from current cpu's swap entry |
643 | * pool (a cluster). This might involve allocating a new cluster for current CPU | |
644 | * too. | |
ebc2a1a6 | 645 | */ |
36005bae | 646 | static bool scan_swap_map_try_ssd_cluster(struct swap_info_struct *si, |
845982eb | 647 | unsigned long *offset, unsigned long *scan_base, int order) |
ebc2a1a6 | 648 | { |
845982eb | 649 | unsigned int nr_pages = 1 << order; |
ebc2a1a6 | 650 | struct percpu_cluster *cluster; |
235b6217 | 651 | struct swap_cluster_info *ci; |
14c62da2 | 652 | unsigned int tmp, max; |
ebc2a1a6 SL |
653 | |
654 | new_cluster: | |
655 | cluster = this_cpu_ptr(si->percpu_cluster); | |
845982eb | 656 | tmp = cluster->next[order]; |
14c62da2 | 657 | if (tmp == SWAP_NEXT_INVALID) { |
6b534915 | 658 | if (!cluster_list_empty(&si->free_clusters)) { |
14c62da2 | 659 | tmp = cluster_next(&si->free_clusters.head) * |
ebc2a1a6 | 660 | SWAPFILE_CLUSTER; |
6b534915 | 661 | } else if (!cluster_list_empty(&si->discard_clusters)) { |
ebc2a1a6 SL |
662 | /* |
663 | * we don't have free cluster but have some clusters in | |
49070588 HY |
664 | * discarding, do discard now and reclaim them, then |
665 | * reread cluster_next_cpu since we dropped si->lock | |
ebc2a1a6 SL |
666 | */ |
667 | swap_do_scheduled_discard(si); | |
49070588 HY |
668 | *scan_base = this_cpu_read(*si->cluster_next_cpu); |
669 | *offset = *scan_base; | |
ebc2a1a6 SL |
670 | goto new_cluster; |
671 | } else | |
36005bae | 672 | return false; |
ebc2a1a6 SL |
673 | } |
674 | ||
ebc2a1a6 SL |
675 | /* |
676 | * Other CPUs can use our cluster if they can't find a free cluster, | |
845982eb RR |
677 | * check if there is still free entry in the cluster, maintaining |
678 | * natural alignment. | |
ebc2a1a6 | 679 | */ |
14c62da2 | 680 | max = min_t(unsigned long, si->max, ALIGN(tmp + 1, SWAPFILE_CLUSTER)); |
7b9e2de1 WY |
681 | if (tmp < max) { |
682 | ci = lock_cluster(si, tmp); | |
683 | while (tmp < max) { | |
845982eb | 684 | if (swap_range_empty(si->swap_map, tmp, nr_pages)) |
7b9e2de1 | 685 | break; |
845982eb | 686 | tmp += nr_pages; |
7b9e2de1 WY |
687 | } |
688 | unlock_cluster(ci); | |
ebc2a1a6 | 689 | } |
0fd0e19e | 690 | if (tmp >= max) { |
845982eb | 691 | cluster->next[order] = SWAP_NEXT_INVALID; |
ebc2a1a6 SL |
692 | goto new_cluster; |
693 | } | |
ebc2a1a6 SL |
694 | *offset = tmp; |
695 | *scan_base = tmp; | |
845982eb RR |
696 | tmp += nr_pages; |
697 | cluster->next[order] = tmp < max ? tmp : SWAP_NEXT_INVALID; | |
fdff1deb | 698 | return true; |
2a8f9449 SL |
699 | } |
700 | ||
a2468cc9 AL |
701 | static void __del_from_avail_list(struct swap_info_struct *p) |
702 | { | |
703 | int nid; | |
704 | ||
6fe7d6b9 | 705 | assert_spin_locked(&p->lock); |
a2468cc9 AL |
706 | for_each_node(nid) |
707 | plist_del(&p->avail_lists[nid], &swap_avail_heads[nid]); | |
708 | } | |
709 | ||
710 | static void del_from_avail_list(struct swap_info_struct *p) | |
711 | { | |
712 | spin_lock(&swap_avail_lock); | |
713 | __del_from_avail_list(p); | |
714 | spin_unlock(&swap_avail_lock); | |
715 | } | |
716 | ||
38d8b4e6 HY |
717 | static void swap_range_alloc(struct swap_info_struct *si, unsigned long offset, |
718 | unsigned int nr_entries) | |
719 | { | |
720 | unsigned int end = offset + nr_entries - 1; | |
721 | ||
722 | if (offset == si->lowest_bit) | |
723 | si->lowest_bit += nr_entries; | |
724 | if (end == si->highest_bit) | |
a449bf58 | 725 | WRITE_ONCE(si->highest_bit, si->highest_bit - nr_entries); |
c8945306 | 726 | WRITE_ONCE(si->inuse_pages, si->inuse_pages + nr_entries); |
38d8b4e6 HY |
727 | if (si->inuse_pages == si->pages) { |
728 | si->lowest_bit = si->max; | |
729 | si->highest_bit = 0; | |
a2468cc9 | 730 | del_from_avail_list(si); |
38d8b4e6 HY |
731 | } |
732 | } | |
733 | ||
a2468cc9 AL |
734 | static void add_to_avail_list(struct swap_info_struct *p) |
735 | { | |
736 | int nid; | |
737 | ||
738 | spin_lock(&swap_avail_lock); | |
67490031 | 739 | for_each_node(nid) |
a2468cc9 | 740 | plist_add(&p->avail_lists[nid], &swap_avail_heads[nid]); |
a2468cc9 AL |
741 | spin_unlock(&swap_avail_lock); |
742 | } | |
743 | ||
38d8b4e6 HY |
744 | static void swap_range_free(struct swap_info_struct *si, unsigned long offset, |
745 | unsigned int nr_entries) | |
746 | { | |
3852f676 | 747 | unsigned long begin = offset; |
38d8b4e6 HY |
748 | unsigned long end = offset + nr_entries - 1; |
749 | void (*swap_slot_free_notify)(struct block_device *, unsigned long); | |
750 | ||
751 | if (offset < si->lowest_bit) | |
752 | si->lowest_bit = offset; | |
753 | if (end > si->highest_bit) { | |
754 | bool was_full = !si->highest_bit; | |
755 | ||
a449bf58 | 756 | WRITE_ONCE(si->highest_bit, end); |
a2468cc9 AL |
757 | if (was_full && (si->flags & SWP_WRITEOK)) |
758 | add_to_avail_list(si); | |
38d8b4e6 | 759 | } |
38d8b4e6 HY |
760 | if (si->flags & SWP_BLKDEV) |
761 | swap_slot_free_notify = | |
762 | si->bdev->bd_disk->fops->swap_slot_free_notify; | |
763 | else | |
764 | swap_slot_free_notify = NULL; | |
765 | while (offset <= end) { | |
8a84802e | 766 | arch_swap_invalidate_page(si->type, offset); |
38d8b4e6 HY |
767 | if (swap_slot_free_notify) |
768 | swap_slot_free_notify(si->bdev, offset); | |
769 | offset++; | |
770 | } | |
3852f676 | 771 | clear_shadow_from_swap_cache(si->type, begin, end); |
64cf264c YA |
772 | |
773 | /* | |
774 | * Make sure that try_to_unuse() observes si->inuse_pages reaching 0 | |
775 | * only after the above cleanups are done. | |
776 | */ | |
777 | smp_wmb(); | |
778 | atomic_long_add(nr_entries, &nr_swap_pages); | |
779 | WRITE_ONCE(si->inuse_pages, si->inuse_pages - nr_entries); | |
38d8b4e6 HY |
780 | } |
781 | ||
49070588 HY |
782 | static void set_cluster_next(struct swap_info_struct *si, unsigned long next) |
783 | { | |
784 | unsigned long prev; | |
785 | ||
786 | if (!(si->flags & SWP_SOLIDSTATE)) { | |
787 | si->cluster_next = next; | |
788 | return; | |
789 | } | |
790 | ||
791 | prev = this_cpu_read(*si->cluster_next_cpu); | |
792 | /* | |
793 | * Cross the swap address space size aligned trunk, choose | |
794 | * another trunk randomly to avoid lock contention on swap | |
795 | * address space if possible. | |
796 | */ | |
797 | if ((prev >> SWAP_ADDRESS_SPACE_SHIFT) != | |
798 | (next >> SWAP_ADDRESS_SPACE_SHIFT)) { | |
799 | /* No free swap slots available */ | |
800 | if (si->highest_bit <= si->lowest_bit) | |
801 | return; | |
e8a533cb | 802 | next = get_random_u32_inclusive(si->lowest_bit, si->highest_bit); |
49070588 HY |
803 | next = ALIGN_DOWN(next, SWAP_ADDRESS_SPACE_PAGES); |
804 | next = max_t(unsigned int, next, si->lowest_bit); | |
805 | } | |
806 | this_cpu_write(*si->cluster_next_cpu, next); | |
807 | } | |
808 | ||
4b9ae842 ML |
809 | static bool swap_offset_available_and_locked(struct swap_info_struct *si, |
810 | unsigned long offset) | |
811 | { | |
812 | if (data_race(!si->swap_map[offset])) { | |
813 | spin_lock(&si->lock); | |
814 | return true; | |
815 | } | |
816 | ||
817 | if (vm_swap_full() && READ_ONCE(si->swap_map[offset]) == SWAP_HAS_CACHE) { | |
818 | spin_lock(&si->lock); | |
819 | return true; | |
820 | } | |
821 | ||
822 | return false; | |
823 | } | |
824 | ||
36005bae TC |
825 | static int scan_swap_map_slots(struct swap_info_struct *si, |
826 | unsigned char usage, int nr, | |
845982eb | 827 | swp_entry_t slots[], int order) |
1da177e4 | 828 | { |
235b6217 | 829 | struct swap_cluster_info *ci; |
ebebbbe9 | 830 | unsigned long offset; |
c60aa176 | 831 | unsigned long scan_base; |
7992fde7 | 832 | unsigned long last_in_cluster = 0; |
048c27fd | 833 | int latency_ration = LATENCY_LIMIT; |
845982eb | 834 | unsigned int nr_pages = 1 << order; |
36005bae | 835 | int n_ret = 0; |
ed43af10 | 836 | bool scanned_many = false; |
36005bae | 837 | |
886bb7e9 | 838 | /* |
7dfad418 HD |
839 | * We try to cluster swap pages by allocating them sequentially |
840 | * in swap. Once we've allocated SWAPFILE_CLUSTER pages this | |
841 | * way, however, we resort to first-free allocation, starting | |
842 | * a new cluster. This prevents us from scattering swap pages | |
843 | * all over the entire swap partition, so that we reduce | |
844 | * overall disk seek times between swap pages. -- sct | |
845 | * But we do now try to find an empty cluster. -Andrea | |
c60aa176 | 846 | * And we let swap pages go all over an SSD partition. Hugh |
7dfad418 HD |
847 | */ |
848 | ||
845982eb RR |
849 | if (order > 0) { |
850 | /* | |
851 | * Should not even be attempting large allocations when huge | |
852 | * page swap is disabled. Warn and fail the allocation. | |
853 | */ | |
854 | if (!IS_ENABLED(CONFIG_THP_SWAP) || | |
855 | nr_pages > SWAPFILE_CLUSTER) { | |
856 | VM_WARN_ON_ONCE(1); | |
857 | return 0; | |
858 | } | |
859 | ||
860 | /* | |
861 | * Swapfile is not block device or not using clusters so unable | |
862 | * to allocate large entries. | |
863 | */ | |
864 | if (!(si->flags & SWP_BLKDEV) || !si->cluster_info) | |
865 | return 0; | |
866 | } | |
867 | ||
52b7efdb | 868 | si->flags += SWP_SCANNING; |
49070588 HY |
869 | /* |
870 | * Use percpu scan base for SSD to reduce lock contention on | |
871 | * cluster and swap cache. For HDD, sequential access is more | |
872 | * important. | |
873 | */ | |
874 | if (si->flags & SWP_SOLIDSTATE) | |
875 | scan_base = this_cpu_read(*si->cluster_next_cpu); | |
876 | else | |
877 | scan_base = si->cluster_next; | |
878 | offset = scan_base; | |
ebebbbe9 | 879 | |
ebc2a1a6 SL |
880 | /* SSD algorithm */ |
881 | if (si->cluster_info) { | |
845982eb RR |
882 | if (!scan_swap_map_try_ssd_cluster(si, &offset, &scan_base, order)) { |
883 | if (order > 0) | |
884 | goto no_page; | |
36005bae | 885 | goto scan; |
845982eb | 886 | } |
f4eaf51a | 887 | } else if (unlikely(!si->cluster_nr--)) { |
ebebbbe9 HD |
888 | if (si->pages - si->inuse_pages < SWAPFILE_CLUSTER) { |
889 | si->cluster_nr = SWAPFILE_CLUSTER - 1; | |
890 | goto checks; | |
891 | } | |
2a8f9449 | 892 | |
ec8acf20 | 893 | spin_unlock(&si->lock); |
7dfad418 | 894 | |
c60aa176 HD |
895 | /* |
896 | * If seek is expensive, start searching for new cluster from | |
897 | * start of partition, to minimize the span of allocated swap. | |
50088c44 CY |
898 | * If seek is cheap, that is the SWP_SOLIDSTATE si->cluster_info |
899 | * case, just handled by scan_swap_map_try_ssd_cluster() above. | |
c60aa176 | 900 | */ |
50088c44 | 901 | scan_base = offset = si->lowest_bit; |
7dfad418 HD |
902 | last_in_cluster = offset + SWAPFILE_CLUSTER - 1; |
903 | ||
904 | /* Locate the first empty (unaligned) cluster */ | |
5ee9562c | 905 | for (; last_in_cluster <= READ_ONCE(si->highest_bit); offset++) { |
1da177e4 | 906 | if (si->swap_map[offset]) |
7dfad418 HD |
907 | last_in_cluster = offset + SWAPFILE_CLUSTER; |
908 | else if (offset == last_in_cluster) { | |
ec8acf20 | 909 | spin_lock(&si->lock); |
ebebbbe9 HD |
910 | offset -= SWAPFILE_CLUSTER - 1; |
911 | si->cluster_next = offset; | |
912 | si->cluster_nr = SWAPFILE_CLUSTER - 1; | |
c60aa176 HD |
913 | goto checks; |
914 | } | |
915 | if (unlikely(--latency_ration < 0)) { | |
916 | cond_resched(); | |
917 | latency_ration = LATENCY_LIMIT; | |
918 | } | |
919 | } | |
920 | ||
921 | offset = scan_base; | |
ec8acf20 | 922 | spin_lock(&si->lock); |
ebebbbe9 | 923 | si->cluster_nr = SWAPFILE_CLUSTER - 1; |
1da177e4 | 924 | } |
7dfad418 | 925 | |
ebebbbe9 | 926 | checks: |
ebc2a1a6 | 927 | if (si->cluster_info) { |
845982eb | 928 | while (scan_swap_map_ssd_cluster_conflict(si, offset, order)) { |
36005bae TC |
929 | /* take a break if we already got some slots */ |
930 | if (n_ret) | |
931 | goto done; | |
932 | if (!scan_swap_map_try_ssd_cluster(si, &offset, | |
845982eb RR |
933 | &scan_base, order)) { |
934 | if (order > 0) | |
935 | goto no_page; | |
36005bae | 936 | goto scan; |
845982eb | 937 | } |
36005bae | 938 | } |
ebc2a1a6 | 939 | } |
ebebbbe9 | 940 | if (!(si->flags & SWP_WRITEOK)) |
52b7efdb | 941 | goto no_page; |
7dfad418 HD |
942 | if (!si->highest_bit) |
943 | goto no_page; | |
ebebbbe9 | 944 | if (offset > si->highest_bit) |
c60aa176 | 945 | scan_base = offset = si->lowest_bit; |
c9e44410 | 946 | |
235b6217 | 947 | ci = lock_cluster(si, offset); |
b73d7fce HD |
948 | /* reuse swap entry of cache-only swap if not busy. */ |
949 | if (vm_swap_full() && si->swap_map[offset] == SWAP_HAS_CACHE) { | |
c9e44410 | 950 | int swap_was_freed; |
235b6217 | 951 | unlock_cluster(ci); |
ec8acf20 | 952 | spin_unlock(&si->lock); |
bcd49e86 | 953 | swap_was_freed = __try_to_reclaim_swap(si, offset, TTRS_ANYWAY); |
ec8acf20 | 954 | spin_lock(&si->lock); |
c9e44410 | 955 | /* entry was freed successfully, try to use this again */ |
a62fb92a | 956 | if (swap_was_freed > 0) |
c9e44410 KH |
957 | goto checks; |
958 | goto scan; /* check next one */ | |
959 | } | |
960 | ||
235b6217 HY |
961 | if (si->swap_map[offset]) { |
962 | unlock_cluster(ci); | |
36005bae TC |
963 | if (!n_ret) |
964 | goto scan; | |
965 | else | |
966 | goto done; | |
235b6217 | 967 | } |
845982eb RR |
968 | memset(si->swap_map + offset, usage, nr_pages); |
969 | add_cluster_info_page(si, si->cluster_info, offset, nr_pages); | |
2872bb2d | 970 | unlock_cluster(ci); |
ebebbbe9 | 971 | |
845982eb | 972 | swap_range_alloc(si, offset, nr_pages); |
36005bae TC |
973 | slots[n_ret++] = swp_entry(si->type, offset); |
974 | ||
975 | /* got enough slots or reach max slots? */ | |
976 | if ((n_ret == nr) || (offset >= si->highest_bit)) | |
977 | goto done; | |
978 | ||
979 | /* search for next available slot */ | |
980 | ||
981 | /* time to take a break? */ | |
982 | if (unlikely(--latency_ration < 0)) { | |
983 | if (n_ret) | |
984 | goto done; | |
985 | spin_unlock(&si->lock); | |
986 | cond_resched(); | |
987 | spin_lock(&si->lock); | |
988 | latency_ration = LATENCY_LIMIT; | |
989 | } | |
990 | ||
991 | /* try to get more slots in cluster */ | |
992 | if (si->cluster_info) { | |
845982eb | 993 | if (scan_swap_map_try_ssd_cluster(si, &offset, &scan_base, order)) |
36005bae | 994 | goto checks; |
845982eb RR |
995 | if (order > 0) |
996 | goto done; | |
f4eaf51a WY |
997 | } else if (si->cluster_nr && !si->swap_map[++offset]) { |
998 | /* non-ssd case, still more slots in cluster? */ | |
36005bae TC |
999 | --si->cluster_nr; |
1000 | goto checks; | |
1001 | } | |
7992fde7 | 1002 | |
ed43af10 HY |
1003 | /* |
1004 | * Even if there's no free clusters available (fragmented), | |
1005 | * try to scan a little more quickly with lock held unless we | |
1006 | * have scanned too many slots already. | |
1007 | */ | |
1008 | if (!scanned_many) { | |
1009 | unsigned long scan_limit; | |
1010 | ||
1011 | if (offset < scan_base) | |
1012 | scan_limit = scan_base; | |
1013 | else | |
1014 | scan_limit = si->highest_bit; | |
1015 | for (; offset <= scan_limit && --latency_ration > 0; | |
1016 | offset++) { | |
1017 | if (!si->swap_map[offset]) | |
1018 | goto checks; | |
1019 | } | |
1020 | } | |
1021 | ||
36005bae | 1022 | done: |
845982eb RR |
1023 | if (order == 0) |
1024 | set_cluster_next(si, offset + 1); | |
36005bae TC |
1025 | si->flags -= SWP_SCANNING; |
1026 | return n_ret; | |
7dfad418 | 1027 | |
ebebbbe9 | 1028 | scan: |
845982eb | 1029 | VM_WARN_ON(order > 0); |
ec8acf20 | 1030 | spin_unlock(&si->lock); |
a449bf58 | 1031 | while (++offset <= READ_ONCE(si->highest_bit)) { |
048c27fd HD |
1032 | if (unlikely(--latency_ration < 0)) { |
1033 | cond_resched(); | |
1034 | latency_ration = LATENCY_LIMIT; | |
ed43af10 | 1035 | scanned_many = true; |
048c27fd | 1036 | } |
de1ccfb6 CW |
1037 | if (swap_offset_available_and_locked(si, offset)) |
1038 | goto checks; | |
7dfad418 | 1039 | } |
c60aa176 | 1040 | offset = si->lowest_bit; |
a5998061 | 1041 | while (offset < scan_base) { |
c60aa176 HD |
1042 | if (unlikely(--latency_ration < 0)) { |
1043 | cond_resched(); | |
1044 | latency_ration = LATENCY_LIMIT; | |
ed43af10 | 1045 | scanned_many = true; |
c60aa176 | 1046 | } |
de1ccfb6 CW |
1047 | if (swap_offset_available_and_locked(si, offset)) |
1048 | goto checks; | |
a5998061 | 1049 | offset++; |
c60aa176 | 1050 | } |
ec8acf20 | 1051 | spin_lock(&si->lock); |
7dfad418 HD |
1052 | |
1053 | no_page: | |
52b7efdb | 1054 | si->flags -= SWP_SCANNING; |
36005bae | 1055 | return n_ret; |
1da177e4 LT |
1056 | } |
1057 | ||
38d8b4e6 HY |
1058 | static void swap_free_cluster(struct swap_info_struct *si, unsigned long idx) |
1059 | { | |
1060 | unsigned long offset = idx * SWAPFILE_CLUSTER; | |
1061 | struct swap_cluster_info *ci; | |
1062 | ||
1063 | ci = lock_cluster(si, offset); | |
979aafa5 | 1064 | memset(si->swap_map + offset, 0, SWAPFILE_CLUSTER); |
38d8b4e6 HY |
1065 | cluster_set_count_flag(ci, 0, 0); |
1066 | free_cluster(si, idx); | |
1067 | unlock_cluster(ci); | |
1068 | swap_range_free(si, offset, SWAPFILE_CLUSTER); | |
1069 | } | |
38d8b4e6 | 1070 | |
9faaa0f8 | 1071 | int get_swap_pages(int n_goal, swp_entry_t swp_entries[], int entry_order) |
1da177e4 | 1072 | { |
9faaa0f8 RR |
1073 | int order = swap_entry_order(entry_order); |
1074 | unsigned long size = 1 << order; | |
adfab836 | 1075 | struct swap_info_struct *si, *next; |
36005bae TC |
1076 | long avail_pgs; |
1077 | int n_ret = 0; | |
a2468cc9 | 1078 | int node; |
1da177e4 | 1079 | |
b50da6e9 ZH |
1080 | spin_lock(&swap_avail_lock); |
1081 | ||
5d5e8f19 | 1082 | avail_pgs = atomic_long_read(&nr_swap_pages) / size; |
b50da6e9 ZH |
1083 | if (avail_pgs <= 0) { |
1084 | spin_unlock(&swap_avail_lock); | |
fb4f88dc | 1085 | goto noswap; |
b50da6e9 | 1086 | } |
36005bae | 1087 | |
08d3090f | 1088 | n_goal = min3((long)n_goal, (long)SWAP_BATCH, avail_pgs); |
36005bae | 1089 | |
5d5e8f19 | 1090 | atomic_long_sub(n_goal * size, &nr_swap_pages); |
fb4f88dc | 1091 | |
18ab4d4c | 1092 | start_over: |
a2468cc9 AL |
1093 | node = numa_node_id(); |
1094 | plist_for_each_entry_safe(si, next, &swap_avail_heads[node], avail_lists[node]) { | |
18ab4d4c | 1095 | /* requeue si to after same-priority siblings */ |
a2468cc9 | 1096 | plist_requeue(&si->avail_lists[node], &swap_avail_heads[node]); |
18ab4d4c | 1097 | spin_unlock(&swap_avail_lock); |
ec8acf20 | 1098 | spin_lock(&si->lock); |
adfab836 | 1099 | if (!si->highest_bit || !(si->flags & SWP_WRITEOK)) { |
18ab4d4c | 1100 | spin_lock(&swap_avail_lock); |
a2468cc9 | 1101 | if (plist_node_empty(&si->avail_lists[node])) { |
18ab4d4c DS |
1102 | spin_unlock(&si->lock); |
1103 | goto nextsi; | |
1104 | } | |
1105 | WARN(!si->highest_bit, | |
1106 | "swap_info %d in list but !highest_bit\n", | |
1107 | si->type); | |
1108 | WARN(!(si->flags & SWP_WRITEOK), | |
1109 | "swap_info %d in list but !SWP_WRITEOK\n", | |
1110 | si->type); | |
a2468cc9 | 1111 | __del_from_avail_list(si); |
ec8acf20 | 1112 | spin_unlock(&si->lock); |
18ab4d4c | 1113 | goto nextsi; |
ec8acf20 | 1114 | } |
845982eb RR |
1115 | n_ret = scan_swap_map_slots(si, SWAP_HAS_CACHE, |
1116 | n_goal, swp_entries, order); | |
ec8acf20 | 1117 | spin_unlock(&si->lock); |
845982eb | 1118 | if (n_ret || size > 1) |
36005bae | 1119 | goto check_out; |
7717fc1a | 1120 | cond_resched(); |
36005bae | 1121 | |
18ab4d4c DS |
1122 | spin_lock(&swap_avail_lock); |
1123 | nextsi: | |
adfab836 DS |
1124 | /* |
1125 | * if we got here, it's likely that si was almost full before, | |
bb243f7d ML |
1126 | * and since scan_swap_map_slots() can drop the si->lock, |
1127 | * multiple callers probably all tried to get a page from the | |
1128 | * same si and it filled up before we could get one; or, the si | |
1129 | * filled up between us dropping swap_avail_lock and taking | |
1130 | * si->lock. Since we dropped the swap_avail_lock, the | |
1131 | * swap_avail_head list may have been modified; so if next is | |
1132 | * still in the swap_avail_head list then try it, otherwise | |
1133 | * start over if we have not gotten any slots. | |
adfab836 | 1134 | */ |
a2468cc9 | 1135 | if (plist_node_empty(&next->avail_lists[node])) |
18ab4d4c | 1136 | goto start_over; |
1da177e4 | 1137 | } |
fb4f88dc | 1138 | |
18ab4d4c DS |
1139 | spin_unlock(&swap_avail_lock); |
1140 | ||
36005bae TC |
1141 | check_out: |
1142 | if (n_ret < n_goal) | |
5d5e8f19 | 1143 | atomic_long_add((long)(n_goal - n_ret) * size, |
38d8b4e6 | 1144 | &nr_swap_pages); |
fb4f88dc | 1145 | noswap: |
36005bae TC |
1146 | return n_ret; |
1147 | } | |
1148 | ||
afba72b1 | 1149 | static struct swap_info_struct *_swap_info_get(swp_entry_t entry) |
1da177e4 | 1150 | { |
73c34b6a | 1151 | struct swap_info_struct *p; |
eb085574 | 1152 | unsigned long offset; |
1da177e4 LT |
1153 | |
1154 | if (!entry.val) | |
1155 | goto out; | |
eb085574 | 1156 | p = swp_swap_info(entry); |
c10d38cc | 1157 | if (!p) |
1da177e4 | 1158 | goto bad_nofile; |
a449bf58 | 1159 | if (data_race(!(p->flags & SWP_USED))) |
1da177e4 LT |
1160 | goto bad_device; |
1161 | offset = swp_offset(entry); | |
1162 | if (offset >= p->max) | |
1163 | goto bad_offset; | |
afba72b1 ML |
1164 | if (data_race(!p->swap_map[swp_offset(entry)])) |
1165 | goto bad_free; | |
1da177e4 LT |
1166 | return p; |
1167 | ||
afba72b1 ML |
1168 | bad_free: |
1169 | pr_err("%s: %s%08lx\n", __func__, Unused_offset, entry.val); | |
1170 | goto out; | |
1da177e4 | 1171 | bad_offset: |
cf532faa | 1172 | pr_err("%s: %s%08lx\n", __func__, Bad_offset, entry.val); |
1da177e4 LT |
1173 | goto out; |
1174 | bad_device: | |
cf532faa | 1175 | pr_err("%s: %s%08lx\n", __func__, Unused_file, entry.val); |
1da177e4 LT |
1176 | goto out; |
1177 | bad_nofile: | |
cf532faa | 1178 | pr_err("%s: %s%08lx\n", __func__, Bad_file, entry.val); |
1da177e4 LT |
1179 | out: |
1180 | return NULL; | |
886bb7e9 | 1181 | } |
1da177e4 | 1182 | |
7c00bafe TC |
1183 | static struct swap_info_struct *swap_info_get_cont(swp_entry_t entry, |
1184 | struct swap_info_struct *q) | |
1185 | { | |
1186 | struct swap_info_struct *p; | |
1187 | ||
1188 | p = _swap_info_get(entry); | |
1189 | ||
1190 | if (p != q) { | |
1191 | if (q != NULL) | |
1192 | spin_unlock(&q->lock); | |
1193 | if (p != NULL) | |
1194 | spin_lock(&p->lock); | |
1195 | } | |
1196 | return p; | |
1197 | } | |
1198 | ||
b32d5f32 HY |
1199 | static unsigned char __swap_entry_free_locked(struct swap_info_struct *p, |
1200 | unsigned long offset, | |
1201 | unsigned char usage) | |
1da177e4 | 1202 | { |
8d69aaee HD |
1203 | unsigned char count; |
1204 | unsigned char has_cache; | |
235b6217 | 1205 | |
253d553b | 1206 | count = p->swap_map[offset]; |
235b6217 | 1207 | |
253d553b HD |
1208 | has_cache = count & SWAP_HAS_CACHE; |
1209 | count &= ~SWAP_HAS_CACHE; | |
355cfa73 | 1210 | |
253d553b | 1211 | if (usage == SWAP_HAS_CACHE) { |
355cfa73 | 1212 | VM_BUG_ON(!has_cache); |
253d553b | 1213 | has_cache = 0; |
aaa46865 HD |
1214 | } else if (count == SWAP_MAP_SHMEM) { |
1215 | /* | |
1216 | * Or we could insist on shmem.c using a special | |
1217 | * swap_shmem_free() and free_shmem_swap_and_cache()... | |
1218 | */ | |
1219 | count = 0; | |
570a335b HD |
1220 | } else if ((count & ~COUNT_CONTINUED) <= SWAP_MAP_MAX) { |
1221 | if (count == COUNT_CONTINUED) { | |
1222 | if (swap_count_continued(p, offset, count)) | |
1223 | count = SWAP_MAP_MAX | COUNT_CONTINUED; | |
1224 | else | |
1225 | count = SWAP_MAP_MAX; | |
1226 | } else | |
1227 | count--; | |
1228 | } | |
253d553b | 1229 | |
253d553b | 1230 | usage = count | has_cache; |
a449bf58 QC |
1231 | if (usage) |
1232 | WRITE_ONCE(p->swap_map[offset], usage); | |
1233 | else | |
1234 | WRITE_ONCE(p->swap_map[offset], SWAP_HAS_CACHE); | |
7c00bafe | 1235 | |
b32d5f32 HY |
1236 | return usage; |
1237 | } | |
1238 | ||
eb085574 | 1239 | /* |
a95722a0 | 1240 | * When we get a swap entry, if there aren't some other ways to |
d4a34d7f HY |
1241 | * prevent swapoff, such as the folio in swap cache is locked, RCU |
1242 | * reader side is locked, etc., the swap entry may become invalid | |
1243 | * because of swapoff. Then, we need to enclose all swap related | |
1244 | * functions with get_swap_device() and put_swap_device(), unless the | |
1245 | * swap functions call get/put_swap_device() by themselves. | |
a95722a0 | 1246 | * |
d4a34d7f HY |
1247 | * RCU reader side lock (including any spinlock) is sufficient to |
1248 | * prevent swapoff, because synchronize_rcu() is called in swapoff() | |
1249 | * before freeing data structures. | |
82b1c07a | 1250 | * |
eb085574 HY |
1251 | * Check whether swap entry is valid in the swap device. If so, |
1252 | * return pointer to swap_info_struct, and keep the swap entry valid | |
1253 | * via preventing the swap device from being swapoff, until | |
1254 | * put_swap_device() is called. Otherwise return NULL. | |
1255 | * | |
eb085574 | 1256 | * Notice that swapoff or swapoff+swapon can still happen before the |
63d8620e ML |
1257 | * percpu_ref_tryget_live() in get_swap_device() or after the |
1258 | * percpu_ref_put() in put_swap_device() if there isn't any other way | |
a95722a0 HY |
1259 | * to prevent swapoff. The caller must be prepared for that. For |
1260 | * example, the following situation is possible. | |
eb085574 HY |
1261 | * |
1262 | * CPU1 CPU2 | |
1263 | * do_swap_page() | |
1264 | * ... swapoff+swapon | |
1265 | * __read_swap_cache_async() | |
1266 | * swapcache_prepare() | |
1267 | * __swap_duplicate() | |
1268 | * // check swap_map | |
1269 | * // verify PTE not changed | |
1270 | * | |
1271 | * In __swap_duplicate(), the swap_map need to be checked before | |
1272 | * changing partly because the specified swap entry may be for another | |
1273 | * swap device which has been swapoff. And in do_swap_page(), after | |
1274 | * the page is read from the swap device, the PTE is verified not | |
1275 | * changed with the page table locked to check whether the swap device | |
1276 | * has been swapoff or swapoff+swapon. | |
1277 | */ | |
1278 | struct swap_info_struct *get_swap_device(swp_entry_t entry) | |
1279 | { | |
1280 | struct swap_info_struct *si; | |
1281 | unsigned long offset; | |
1282 | ||
1283 | if (!entry.val) | |
1284 | goto out; | |
1285 | si = swp_swap_info(entry); | |
1286 | if (!si) | |
1287 | goto bad_nofile; | |
63d8620e ML |
1288 | if (!percpu_ref_tryget_live(&si->users)) |
1289 | goto out; | |
1290 | /* | |
1291 | * Guarantee the si->users are checked before accessing other | |
1292 | * fields of swap_info_struct. | |
1293 | * | |
1294 | * Paired with the spin_unlock() after setup_swap_info() in | |
1295 | * enable_swap_info(). | |
1296 | */ | |
1297 | smp_rmb(); | |
eb085574 HY |
1298 | offset = swp_offset(entry); |
1299 | if (offset >= si->max) | |
63d8620e | 1300 | goto put_out; |
eb085574 HY |
1301 | |
1302 | return si; | |
1303 | bad_nofile: | |
1304 | pr_err("%s: %s%08lx\n", __func__, Bad_file, entry.val); | |
1305 | out: | |
1306 | return NULL; | |
63d8620e | 1307 | put_out: |
23b230ba | 1308 | pr_err("%s: %s%08lx\n", __func__, Bad_offset, entry.val); |
63d8620e | 1309 | percpu_ref_put(&si->users); |
eb085574 HY |
1310 | return NULL; |
1311 | } | |
1312 | ||
b32d5f32 | 1313 | static unsigned char __swap_entry_free(struct swap_info_struct *p, |
33e16272 | 1314 | swp_entry_t entry) |
b32d5f32 HY |
1315 | { |
1316 | struct swap_cluster_info *ci; | |
1317 | unsigned long offset = swp_offset(entry); | |
33e16272 | 1318 | unsigned char usage; |
b32d5f32 HY |
1319 | |
1320 | ci = lock_cluster_or_swap_info(p, offset); | |
33e16272 | 1321 | usage = __swap_entry_free_locked(p, offset, 1); |
7c00bafe | 1322 | unlock_cluster_or_swap_info(p, ci); |
10e364da HY |
1323 | if (!usage) |
1324 | free_swap_slot(entry); | |
7c00bafe TC |
1325 | |
1326 | return usage; | |
1327 | } | |
355cfa73 | 1328 | |
7c00bafe TC |
1329 | static void swap_entry_free(struct swap_info_struct *p, swp_entry_t entry) |
1330 | { | |
1331 | struct swap_cluster_info *ci; | |
1332 | unsigned long offset = swp_offset(entry); | |
1333 | unsigned char count; | |
1334 | ||
1335 | ci = lock_cluster(p, offset); | |
1336 | count = p->swap_map[offset]; | |
1337 | VM_BUG_ON(count != SWAP_HAS_CACHE); | |
1338 | p->swap_map[offset] = 0; | |
1339 | dec_cluster_info_page(p, p->cluster_info, offset); | |
235b6217 HY |
1340 | unlock_cluster(ci); |
1341 | ||
38d8b4e6 HY |
1342 | mem_cgroup_uncharge_swap(entry, 1); |
1343 | swap_range_free(p, offset, 1); | |
1da177e4 LT |
1344 | } |
1345 | ||
ebfba004 CH |
1346 | static void cluster_swap_free_nr(struct swap_info_struct *sis, |
1347 | unsigned long offset, int nr_pages) | |
1348 | { | |
1349 | struct swap_cluster_info *ci; | |
1350 | DECLARE_BITMAP(to_free, BITS_PER_LONG) = { 0 }; | |
1351 | int i, nr; | |
1352 | ||
1353 | ci = lock_cluster_or_swap_info(sis, offset); | |
1354 | while (nr_pages) { | |
1355 | nr = min(BITS_PER_LONG, nr_pages); | |
1356 | for (i = 0; i < nr; i++) { | |
1357 | if (!__swap_entry_free_locked(sis, offset + i, 1)) | |
1358 | bitmap_set(to_free, i, 1); | |
1359 | } | |
1360 | if (!bitmap_empty(to_free, BITS_PER_LONG)) { | |
1361 | unlock_cluster_or_swap_info(sis, ci); | |
1362 | for_each_set_bit(i, to_free, BITS_PER_LONG) | |
1363 | free_swap_slot(swp_entry(sis->type, offset + i)); | |
1364 | if (nr == nr_pages) | |
1365 | return; | |
1366 | bitmap_clear(to_free, 0, BITS_PER_LONG); | |
1367 | ci = lock_cluster_or_swap_info(sis, offset); | |
1368 | } | |
1369 | offset += nr; | |
1370 | nr_pages -= nr; | |
1371 | } | |
1372 | unlock_cluster_or_swap_info(sis, ci); | |
1373 | } | |
1374 | ||
54f7a49c BS |
1375 | /* |
1376 | * Caller has made sure that the swap device corresponding to entry | |
1377 | * is still around or has not been recycled. | |
1378 | */ | |
ebfba004 CH |
1379 | void swap_free_nr(swp_entry_t entry, int nr_pages) |
1380 | { | |
1381 | int nr; | |
1382 | struct swap_info_struct *sis; | |
1383 | unsigned long offset = swp_offset(entry); | |
1384 | ||
1385 | sis = _swap_info_get(entry); | |
1386 | if (!sis) | |
1387 | return; | |
1388 | ||
1389 | while (nr_pages) { | |
1390 | nr = min_t(int, nr_pages, SWAPFILE_CLUSTER - offset % SWAPFILE_CLUSTER); | |
1391 | cluster_swap_free_nr(sis, offset, nr); | |
1392 | offset += nr; | |
1393 | nr_pages -= nr; | |
1394 | } | |
1395 | } | |
1396 | ||
cb4b86ba KH |
1397 | /* |
1398 | * Called after dropping swapcache to decrease refcnt to swap entries. | |
1399 | */ | |
4081f744 | 1400 | void put_swap_folio(struct folio *folio, swp_entry_t entry) |
38d8b4e6 HY |
1401 | { |
1402 | unsigned long offset = swp_offset(entry); | |
1403 | unsigned long idx = offset / SWAPFILE_CLUSTER; | |
1404 | struct swap_cluster_info *ci; | |
1405 | struct swap_info_struct *si; | |
1406 | unsigned char *map; | |
a3aea839 HY |
1407 | unsigned int i, free_entries = 0; |
1408 | unsigned char val; | |
9faaa0f8 | 1409 | int size = 1 << swap_entry_order(folio_order(folio)); |
fe5266d5 | 1410 | |
a3aea839 | 1411 | si = _swap_info_get(entry); |
38d8b4e6 HY |
1412 | if (!si) |
1413 | return; | |
1414 | ||
c2343d27 | 1415 | ci = lock_cluster_or_swap_info(si, offset); |
a448f2d0 | 1416 | if (size == SWAPFILE_CLUSTER) { |
a448f2d0 HY |
1417 | map = si->swap_map + offset; |
1418 | for (i = 0; i < SWAPFILE_CLUSTER; i++) { | |
1419 | val = map[i]; | |
1420 | VM_BUG_ON(!(val & SWAP_HAS_CACHE)); | |
1421 | if (val == SWAP_HAS_CACHE) | |
1422 | free_entries++; | |
1423 | } | |
a448f2d0 | 1424 | if (free_entries == SWAPFILE_CLUSTER) { |
c2343d27 | 1425 | unlock_cluster_or_swap_info(si, ci); |
a448f2d0 | 1426 | spin_lock(&si->lock); |
a448f2d0 HY |
1427 | mem_cgroup_uncharge_swap(entry, SWAPFILE_CLUSTER); |
1428 | swap_free_cluster(si, idx); | |
1429 | spin_unlock(&si->lock); | |
1430 | return; | |
1431 | } | |
1432 | } | |
c2343d27 HY |
1433 | for (i = 0; i < size; i++, entry.val++) { |
1434 | if (!__swap_entry_free_locked(si, offset + i, SWAP_HAS_CACHE)) { | |
1435 | unlock_cluster_or_swap_info(si, ci); | |
1436 | free_swap_slot(entry); | |
1437 | if (i == size - 1) | |
1438 | return; | |
1439 | lock_cluster_or_swap_info(si, offset); | |
a3aea839 HY |
1440 | } |
1441 | } | |
c2343d27 | 1442 | unlock_cluster_or_swap_info(si, ci); |
38d8b4e6 | 1443 | } |
59807685 | 1444 | |
155b5f88 HY |
1445 | static int swp_entry_cmp(const void *ent1, const void *ent2) |
1446 | { | |
1447 | const swp_entry_t *e1 = ent1, *e2 = ent2; | |
1448 | ||
1449 | return (int)swp_type(*e1) - (int)swp_type(*e2); | |
1450 | } | |
1451 | ||
7c00bafe TC |
1452 | void swapcache_free_entries(swp_entry_t *entries, int n) |
1453 | { | |
1454 | struct swap_info_struct *p, *prev; | |
1455 | int i; | |
1456 | ||
1457 | if (n <= 0) | |
1458 | return; | |
1459 | ||
1460 | prev = NULL; | |
1461 | p = NULL; | |
155b5f88 HY |
1462 | |
1463 | /* | |
1464 | * Sort swap entries by swap device, so each lock is only taken once. | |
1465 | * nr_swapfiles isn't absolutely correct, but the overhead of sort() is | |
1466 | * so low that it isn't necessary to optimize further. | |
1467 | */ | |
1468 | if (nr_swapfiles > 1) | |
1469 | sort(entries, n, sizeof(entries[0]), swp_entry_cmp, NULL); | |
7c00bafe TC |
1470 | for (i = 0; i < n; ++i) { |
1471 | p = swap_info_get_cont(entries[i], prev); | |
1472 | if (p) | |
1473 | swap_entry_free(p, entries[i]); | |
7c00bafe TC |
1474 | prev = p; |
1475 | } | |
235b6217 | 1476 | if (p) |
7c00bafe | 1477 | spin_unlock(&p->lock); |
cb4b86ba KH |
1478 | } |
1479 | ||
eb085574 | 1480 | int __swap_count(swp_entry_t entry) |
aa8d22a1 | 1481 | { |
f9f956b5 | 1482 | struct swap_info_struct *si = swp_swap_info(entry); |
aa8d22a1 MK |
1483 | pgoff_t offset = swp_offset(entry); |
1484 | ||
f9f956b5 | 1485 | return swap_count(si->swap_map[offset]); |
aa8d22a1 MK |
1486 | } |
1487 | ||
14d01ee9 MWO |
1488 | /* |
1489 | * How many references to @entry are currently swapped out? | |
1490 | * This does not give an exact answer when swap count is continued, | |
1491 | * but does include the high COUNT_CONTINUED flag to allow for that. | |
1492 | */ | |
3ecdeb0f | 1493 | int swap_swapcount(struct swap_info_struct *si, swp_entry_t entry) |
322b8afe | 1494 | { |
322b8afe HY |
1495 | pgoff_t offset = swp_offset(entry); |
1496 | struct swap_cluster_info *ci; | |
14d01ee9 | 1497 | int count; |
322b8afe HY |
1498 | |
1499 | ci = lock_cluster_or_swap_info(si, offset); | |
1500 | count = swap_count(si->swap_map[offset]); | |
1501 | unlock_cluster_or_swap_info(si, ci); | |
1502 | return count; | |
1503 | } | |
1504 | ||
8334b962 MK |
1505 | /* |
1506 | * How many references to @entry are currently swapped out? | |
1507 | * This considers COUNT_CONTINUED so it returns exact answer. | |
1508 | */ | |
1509 | int swp_swapcount(swp_entry_t entry) | |
1510 | { | |
1511 | int count, tmp_count, n; | |
1512 | struct swap_info_struct *p; | |
235b6217 | 1513 | struct swap_cluster_info *ci; |
8334b962 MK |
1514 | struct page *page; |
1515 | pgoff_t offset; | |
1516 | unsigned char *map; | |
1517 | ||
235b6217 | 1518 | p = _swap_info_get(entry); |
8334b962 MK |
1519 | if (!p) |
1520 | return 0; | |
1521 | ||
235b6217 HY |
1522 | offset = swp_offset(entry); |
1523 | ||
1524 | ci = lock_cluster_or_swap_info(p, offset); | |
1525 | ||
1526 | count = swap_count(p->swap_map[offset]); | |
8334b962 MK |
1527 | if (!(count & COUNT_CONTINUED)) |
1528 | goto out; | |
1529 | ||
1530 | count &= ~COUNT_CONTINUED; | |
1531 | n = SWAP_MAP_MAX + 1; | |
1532 | ||
8334b962 MK |
1533 | page = vmalloc_to_page(p->swap_map + offset); |
1534 | offset &= ~PAGE_MASK; | |
1535 | VM_BUG_ON(page_private(page) != SWP_CONTINUED); | |
1536 | ||
1537 | do { | |
a8ae4991 | 1538 | page = list_next_entry(page, lru); |
829c3151 | 1539 | map = kmap_local_page(page); |
8334b962 | 1540 | tmp_count = map[offset]; |
829c3151 | 1541 | kunmap_local(map); |
8334b962 MK |
1542 | |
1543 | count += (tmp_count & ~COUNT_CONTINUED) * n; | |
1544 | n *= (SWAP_CONT_MAX + 1); | |
1545 | } while (tmp_count & COUNT_CONTINUED); | |
1546 | out: | |
235b6217 | 1547 | unlock_cluster_or_swap_info(p, ci); |
8334b962 MK |
1548 | return count; |
1549 | } | |
1550 | ||
e0709829 | 1551 | static bool swap_page_trans_huge_swapped(struct swap_info_struct *si, |
d7d0d389 | 1552 | swp_entry_t entry, int order) |
e0709829 HY |
1553 | { |
1554 | struct swap_cluster_info *ci; | |
1555 | unsigned char *map = si->swap_map; | |
d7d0d389 | 1556 | unsigned int nr_pages = 1 << order; |
e0709829 | 1557 | unsigned long roffset = swp_offset(entry); |
d7d0d389 | 1558 | unsigned long offset = round_down(roffset, nr_pages); |
e0709829 HY |
1559 | int i; |
1560 | bool ret = false; | |
1561 | ||
1562 | ci = lock_cluster_or_swap_info(si, offset); | |
d7d0d389 | 1563 | if (!ci || nr_pages == 1) { |
afa4711e | 1564 | if (swap_count(map[roffset])) |
e0709829 HY |
1565 | ret = true; |
1566 | goto unlock_out; | |
1567 | } | |
d7d0d389 | 1568 | for (i = 0; i < nr_pages; i++) { |
afa4711e | 1569 | if (swap_count(map[offset + i])) { |
e0709829 HY |
1570 | ret = true; |
1571 | break; | |
1572 | } | |
1573 | } | |
1574 | unlock_out: | |
1575 | unlock_cluster_or_swap_info(si, ci); | |
1576 | return ret; | |
1577 | } | |
1578 | ||
2397f780 | 1579 | static bool folio_swapped(struct folio *folio) |
e0709829 | 1580 | { |
3d2c9087 | 1581 | swp_entry_t entry = folio->swap; |
14d01ee9 MWO |
1582 | struct swap_info_struct *si = _swap_info_get(entry); |
1583 | ||
1584 | if (!si) | |
1585 | return false; | |
e0709829 | 1586 | |
2397f780 | 1587 | if (!IS_ENABLED(CONFIG_THP_SWAP) || likely(!folio_test_large(folio))) |
14d01ee9 | 1588 | return swap_swapcount(si, entry) != 0; |
e0709829 | 1589 | |
d7d0d389 | 1590 | return swap_page_trans_huge_swapped(si, entry, folio_order(folio)); |
e0709829 | 1591 | } |
ba3c4ce6 | 1592 | |
bdb0ed54 MWO |
1593 | /** |
1594 | * folio_free_swap() - Free the swap space used for this folio. | |
1595 | * @folio: The folio to remove. | |
1596 | * | |
1597 | * If swap is getting full, or if there are no more mappings of this folio, | |
1598 | * then call folio_free_swap to free its swap space. | |
1599 | * | |
1600 | * Return: true if we were able to release the swap space. | |
1da177e4 | 1601 | */ |
bdb0ed54 | 1602 | bool folio_free_swap(struct folio *folio) |
1da177e4 | 1603 | { |
2397f780 | 1604 | VM_BUG_ON_FOLIO(!folio_test_locked(folio), folio); |
1da177e4 | 1605 | |
2397f780 | 1606 | if (!folio_test_swapcache(folio)) |
bdb0ed54 | 1607 | return false; |
2397f780 | 1608 | if (folio_test_writeback(folio)) |
bdb0ed54 | 1609 | return false; |
2397f780 | 1610 | if (folio_swapped(folio)) |
bdb0ed54 | 1611 | return false; |
1da177e4 | 1612 | |
b73d7fce HD |
1613 | /* |
1614 | * Once hibernation has begun to create its image of memory, | |
bdb0ed54 | 1615 | * there's a danger that one of the calls to folio_free_swap() |
b73d7fce HD |
1616 | * - most probably a call from __try_to_reclaim_swap() while |
1617 | * hibernation is allocating its own swap pages for the image, | |
1618 | * but conceivably even a call from memory reclaim - will free | |
bdb0ed54 MWO |
1619 | * the swap from a folio which has already been recorded in the |
1620 | * image as a clean swapcache folio, and then reuse its swap for | |
b73d7fce | 1621 | * another page of the image. On waking from hibernation, the |
bdb0ed54 | 1622 | * original folio might be freed under memory pressure, then |
b73d7fce HD |
1623 | * later read back in from swap, now with the wrong data. |
1624 | * | |
2de1a7e4 | 1625 | * Hibernation suspends storage while it is writing the image |
f90ac398 | 1626 | * to disk so check that here. |
b73d7fce | 1627 | */ |
f90ac398 | 1628 | if (pm_suspended_storage()) |
bdb0ed54 | 1629 | return false; |
b73d7fce | 1630 | |
75fa68a5 | 1631 | delete_from_swap_cache(folio); |
2397f780 | 1632 | folio_set_dirty(folio); |
bdb0ed54 | 1633 | return true; |
68a22394 RR |
1634 | } |
1635 | ||
a62fb92a RR |
1636 | /** |
1637 | * free_swap_and_cache_nr() - Release reference on range of swap entries and | |
1638 | * reclaim their cache if no more references remain. | |
1639 | * @entry: First entry of range. | |
1640 | * @nr: Number of entries in range. | |
1641 | * | |
1642 | * For each swap entry in the contiguous range, release a reference. If any swap | |
1643 | * entries become free, try to reclaim their underlying folios, if present. The | |
1644 | * offset range is defined by [entry.offset, entry.offset + nr). | |
1da177e4 | 1645 | */ |
a62fb92a | 1646 | void free_swap_and_cache_nr(swp_entry_t entry, int nr) |
1da177e4 | 1647 | { |
a62fb92a RR |
1648 | const unsigned long start_offset = swp_offset(entry); |
1649 | const unsigned long end_offset = start_offset + nr; | |
1650 | unsigned int type = swp_type(entry); | |
1651 | struct swap_info_struct *si; | |
1652 | bool any_only_cache = false; | |
1653 | unsigned long offset; | |
7c00bafe | 1654 | unsigned char count; |
1da177e4 | 1655 | |
a7420aa5 | 1656 | if (non_swap_entry(entry)) |
a62fb92a RR |
1657 | return; |
1658 | ||
1659 | si = get_swap_device(entry); | |
1660 | if (!si) | |
1661 | return; | |
1662 | ||
1663 | if (WARN_ON(end_offset > si->max)) | |
1664 | goto out; | |
0697212a | 1665 | |
a62fb92a RR |
1666 | /* |
1667 | * First free all entries in the range. | |
1668 | */ | |
1669 | for (offset = start_offset; offset < end_offset; offset++) { | |
1670 | if (data_race(si->swap_map[offset])) { | |
1671 | count = __swap_entry_free(si, swp_entry(type, offset)); | |
1672 | if (count == SWAP_HAS_CACHE) | |
1673 | any_only_cache = true; | |
1674 | } else { | |
1675 | WARN_ON_ONCE(1); | |
82b1c07a | 1676 | } |
a62fb92a RR |
1677 | } |
1678 | ||
1679 | /* | |
1680 | * Short-circuit the below loop if none of the entries had their | |
1681 | * reference drop to zero. | |
1682 | */ | |
1683 | if (!any_only_cache) | |
1684 | goto out; | |
82b1c07a | 1685 | |
a62fb92a RR |
1686 | /* |
1687 | * Now go back over the range trying to reclaim the swap cache. This is | |
1688 | * more efficient for large folios because we will only try to reclaim | |
1689 | * the swap once per folio in the common case. If we do | |
1690 | * __swap_entry_free() and __try_to_reclaim_swap() in the same loop, the | |
1691 | * latter will get a reference and lock the folio for every individual | |
1692 | * page but will only succeed once the swap slot for every subpage is | |
1693 | * zero. | |
1694 | */ | |
1695 | for (offset = start_offset; offset < end_offset; offset += nr) { | |
1696 | nr = 1; | |
1697 | if (READ_ONCE(si->swap_map[offset]) == SWAP_HAS_CACHE) { | |
1698 | /* | |
1699 | * Folios are always naturally aligned in swap so | |
1700 | * advance forward to the next boundary. Zero means no | |
1701 | * folio was found for the swap entry, so advance by 1 | |
1702 | * in this case. Negative value means folio was found | |
1703 | * but could not be reclaimed. Here we can still advance | |
1704 | * to the next boundary. | |
1705 | */ | |
1706 | nr = __try_to_reclaim_swap(si, offset, | |
bcd49e86 | 1707 | TTRS_UNMAPPED | TTRS_FULL); |
a62fb92a RR |
1708 | if (nr == 0) |
1709 | nr = 1; | |
1710 | else if (nr < 0) | |
1711 | nr = -nr; | |
1712 | nr = ALIGN(offset + 1, nr) - offset; | |
1713 | } | |
1da177e4 | 1714 | } |
a62fb92a RR |
1715 | |
1716 | out: | |
1717 | put_swap_device(si); | |
1da177e4 LT |
1718 | } |
1719 | ||
b0cb1a19 | 1720 | #ifdef CONFIG_HIBERNATION |
bb243f7d ML |
1721 | |
1722 | swp_entry_t get_swap_page_of_type(int type) | |
1723 | { | |
1724 | struct swap_info_struct *si = swap_type_to_swap_info(type); | |
1725 | swp_entry_t entry = {0}; | |
1726 | ||
1727 | if (!si) | |
1728 | goto fail; | |
1729 | ||
1730 | /* This is called for allocating swap entry, not cache */ | |
1731 | spin_lock(&si->lock); | |
845982eb | 1732 | if ((si->flags & SWP_WRITEOK) && scan_swap_map_slots(si, 1, 1, &entry, 0)) |
bb243f7d ML |
1733 | atomic_long_dec(&nr_swap_pages); |
1734 | spin_unlock(&si->lock); | |
1735 | fail: | |
1736 | return entry; | |
1737 | } | |
1738 | ||
f577eb30 | 1739 | /* |
915bae9e | 1740 | * Find the swap type that corresponds to given device (if any). |
f577eb30 | 1741 | * |
915bae9e RW |
1742 | * @offset - number of the PAGE_SIZE-sized block of the device, starting |
1743 | * from 0, in which the swap header is expected to be located. | |
1744 | * | |
1745 | * This is needed for the suspend to disk (aka swsusp). | |
f577eb30 | 1746 | */ |
21bd9005 | 1747 | int swap_type_of(dev_t device, sector_t offset) |
f577eb30 | 1748 | { |
efa90a98 | 1749 | int type; |
f577eb30 | 1750 | |
21bd9005 CH |
1751 | if (!device) |
1752 | return -1; | |
915bae9e | 1753 | |
f577eb30 | 1754 | spin_lock(&swap_lock); |
efa90a98 HD |
1755 | for (type = 0; type < nr_swapfiles; type++) { |
1756 | struct swap_info_struct *sis = swap_info[type]; | |
f577eb30 | 1757 | |
915bae9e | 1758 | if (!(sis->flags & SWP_WRITEOK)) |
f577eb30 | 1759 | continue; |
b6b5bce3 | 1760 | |
21bd9005 | 1761 | if (device == sis->bdev->bd_dev) { |
4efaceb1 | 1762 | struct swap_extent *se = first_se(sis); |
915bae9e | 1763 | |
915bae9e RW |
1764 | if (se->start_block == offset) { |
1765 | spin_unlock(&swap_lock); | |
efa90a98 | 1766 | return type; |
915bae9e | 1767 | } |
f577eb30 RW |
1768 | } |
1769 | } | |
1770 | spin_unlock(&swap_lock); | |
21bd9005 CH |
1771 | return -ENODEV; |
1772 | } | |
915bae9e | 1773 | |
21bd9005 CH |
1774 | int find_first_swap(dev_t *device) |
1775 | { | |
1776 | int type; | |
915bae9e | 1777 | |
21bd9005 CH |
1778 | spin_lock(&swap_lock); |
1779 | for (type = 0; type < nr_swapfiles; type++) { | |
1780 | struct swap_info_struct *sis = swap_info[type]; | |
1781 | ||
1782 | if (!(sis->flags & SWP_WRITEOK)) | |
1783 | continue; | |
1784 | *device = sis->bdev->bd_dev; | |
1785 | spin_unlock(&swap_lock); | |
1786 | return type; | |
1787 | } | |
1788 | spin_unlock(&swap_lock); | |
f577eb30 RW |
1789 | return -ENODEV; |
1790 | } | |
1791 | ||
73c34b6a HD |
1792 | /* |
1793 | * Get the (PAGE_SIZE) block corresponding to given offset on the swapdev | |
1794 | * corresponding to given index in swap_info (swap type). | |
1795 | */ | |
1796 | sector_t swapdev_block(int type, pgoff_t offset) | |
1797 | { | |
c10d38cc | 1798 | struct swap_info_struct *si = swap_type_to_swap_info(type); |
f885056a | 1799 | struct swap_extent *se; |
73c34b6a | 1800 | |
c10d38cc | 1801 | if (!si || !(si->flags & SWP_WRITEOK)) |
73c34b6a | 1802 | return 0; |
f885056a CH |
1803 | se = offset_to_swap_extent(si, offset); |
1804 | return se->start_block + (offset - se->start_page); | |
73c34b6a HD |
1805 | } |
1806 | ||
f577eb30 RW |
1807 | /* |
1808 | * Return either the total number of swap pages of given type, or the number | |
1809 | * of free pages of that type (depending on @free) | |
1810 | * | |
1811 | * This is needed for software suspend | |
1812 | */ | |
1813 | unsigned int count_swap_pages(int type, int free) | |
1814 | { | |
1815 | unsigned int n = 0; | |
1816 | ||
efa90a98 HD |
1817 | spin_lock(&swap_lock); |
1818 | if ((unsigned int)type < nr_swapfiles) { | |
1819 | struct swap_info_struct *sis = swap_info[type]; | |
1820 | ||
ec8acf20 | 1821 | spin_lock(&sis->lock); |
efa90a98 HD |
1822 | if (sis->flags & SWP_WRITEOK) { |
1823 | n = sis->pages; | |
f577eb30 | 1824 | if (free) |
efa90a98 | 1825 | n -= sis->inuse_pages; |
f577eb30 | 1826 | } |
ec8acf20 | 1827 | spin_unlock(&sis->lock); |
f577eb30 | 1828 | } |
efa90a98 | 1829 | spin_unlock(&swap_lock); |
f577eb30 RW |
1830 | return n; |
1831 | } | |
73c34b6a | 1832 | #endif /* CONFIG_HIBERNATION */ |
f577eb30 | 1833 | |
9f8bdb3f | 1834 | static inline int pte_same_as_swp(pte_t pte, pte_t swp_pte) |
179ef71c | 1835 | { |
099dd687 | 1836 | return pte_same(pte_swp_clear_flags(pte), swp_pte); |
179ef71c CG |
1837 | } |
1838 | ||
1da177e4 | 1839 | /* |
72866f6f HD |
1840 | * No need to decide whether this PTE shares the swap entry with others, |
1841 | * just let do_wp_page work it out if a write is requested later - to | |
1842 | * force COW, vm_page_prot omits write permission from any private vma. | |
1da177e4 | 1843 | */ |
044d66c1 | 1844 | static int unuse_pte(struct vm_area_struct *vma, pmd_t *pmd, |
f102cd8b | 1845 | unsigned long addr, swp_entry_t entry, struct folio *folio) |
1da177e4 | 1846 | { |
f00f4843 MWO |
1847 | struct page *page; |
1848 | struct folio *swapcache; | |
044d66c1 | 1849 | spinlock_t *ptl; |
c33c7948 | 1850 | pte_t *pte, new_pte, old_pte; |
f00f4843 | 1851 | bool hwpoisoned = false; |
044d66c1 HD |
1852 | int ret = 1; |
1853 | ||
f00f4843 | 1854 | swapcache = folio; |
96db66d9 MWO |
1855 | folio = ksm_might_need_to_copy(folio, vma, addr); |
1856 | if (unlikely(!folio)) | |
9e16b7fb | 1857 | return -ENOMEM; |
f00f4843 MWO |
1858 | else if (unlikely(folio == ERR_PTR(-EHWPOISON))) { |
1859 | hwpoisoned = true; | |
1860 | folio = swapcache; | |
1861 | } | |
1862 | ||
1863 | page = folio_file_page(folio, swp_offset(entry)); | |
1864 | if (PageHWPoison(page)) | |
f985fc32 | 1865 | hwpoisoned = true; |
9e16b7fb | 1866 | |
044d66c1 | 1867 | pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl); |
c33c7948 RR |
1868 | if (unlikely(!pte || !pte_same_as_swp(ptep_get(pte), |
1869 | swp_entry_to_pte(entry)))) { | |
044d66c1 HD |
1870 | ret = 0; |
1871 | goto out; | |
1872 | } | |
8a9f3ccd | 1873 | |
c33c7948 RR |
1874 | old_pte = ptep_get(pte); |
1875 | ||
f00f4843 | 1876 | if (unlikely(hwpoisoned || !folio_test_uptodate(folio))) { |
6b970599 | 1877 | swp_entry_t swp_entry; |
9f186f9e ML |
1878 | |
1879 | dec_mm_counter(vma->vm_mm, MM_SWAPENTS); | |
f985fc32 | 1880 | if (hwpoisoned) { |
f00f4843 | 1881 | swp_entry = make_hwpoison_entry(page); |
6b970599 | 1882 | } else { |
af19487f | 1883 | swp_entry = make_poisoned_swp_entry(); |
6b970599 KW |
1884 | } |
1885 | new_pte = swp_entry_to_pte(swp_entry); | |
9f186f9e | 1886 | ret = 0; |
6b970599 | 1887 | goto setpte; |
9f186f9e ML |
1888 | } |
1889 | ||
b53e24c4 PC |
1890 | /* |
1891 | * Some architectures may have to restore extra metadata to the page | |
1892 | * when reading from swap. This metadata may be indexed by swap entry | |
1893 | * so this must be called before swap_free(). | |
1894 | */ | |
f238b8c3 | 1895 | arch_swap_restore(folio_swap(entry, folio), folio); |
b53e24c4 | 1896 | |
b084d435 | 1897 | dec_mm_counter(vma->vm_mm, MM_SWAPENTS); |
d559db08 | 1898 | inc_mm_counter(vma->vm_mm, MM_ANONPAGES); |
f00f4843 MWO |
1899 | folio_get(folio); |
1900 | if (folio == swapcache) { | |
1493a191 DH |
1901 | rmap_t rmap_flags = RMAP_NONE; |
1902 | ||
1903 | /* | |
f00f4843 MWO |
1904 | * See do_swap_page(): writeback would be problematic. |
1905 | * However, we do a folio_wait_writeback() just before this | |
1906 | * call and have the folio locked. | |
1493a191 | 1907 | */ |
f00f4843 | 1908 | VM_BUG_ON_FOLIO(folio_test_writeback(folio), folio); |
c33c7948 | 1909 | if (pte_swp_exclusive(old_pte)) |
1493a191 | 1910 | rmap_flags |= RMAP_EXCLUSIVE; |
9ae2feac BS |
1911 | /* |
1912 | * We currently only expect small !anon folios, which are either | |
1913 | * fully exclusive or fully shared. If we ever get large folios | |
1914 | * here, we have to be careful. | |
1915 | */ | |
1916 | if (!folio_test_anon(folio)) { | |
1917 | VM_WARN_ON_ONCE(folio_test_large(folio)); | |
1918 | VM_WARN_ON_FOLIO(!folio_test_locked(folio), folio); | |
1919 | folio_add_new_anon_rmap(folio, vma, addr, rmap_flags); | |
1920 | } else { | |
1921 | folio_add_anon_rmap_pte(folio, page, vma, addr, rmap_flags); | |
1922 | } | |
00501b53 | 1923 | } else { /* ksm created a completely new copy */ |
15bde4ab | 1924 | folio_add_new_anon_rmap(folio, vma, addr, RMAP_EXCLUSIVE); |
f00f4843 | 1925 | folio_add_lru_vma(folio, vma); |
00501b53 | 1926 | } |
14a762dd | 1927 | new_pte = pte_mkold(mk_pte(page, vma->vm_page_prot)); |
c33c7948 | 1928 | if (pte_swp_soft_dirty(old_pte)) |
14a762dd | 1929 | new_pte = pte_mksoft_dirty(new_pte); |
c33c7948 | 1930 | if (pte_swp_uffd_wp(old_pte)) |
14a762dd | 1931 | new_pte = pte_mkuffd_wp(new_pte); |
6b970599 | 1932 | setpte: |
14a762dd | 1933 | set_pte_at(vma->vm_mm, addr, pte, new_pte); |
1da177e4 | 1934 | swap_free(entry); |
044d66c1 | 1935 | out: |
d850fa72 HD |
1936 | if (pte) |
1937 | pte_unmap_unlock(pte, ptl); | |
f00f4843 MWO |
1938 | if (folio != swapcache) { |
1939 | folio_unlock(folio); | |
1940 | folio_put(folio); | |
9e16b7fb | 1941 | } |
044d66c1 | 1942 | return ret; |
1da177e4 LT |
1943 | } |
1944 | ||
1945 | static int unuse_pte_range(struct vm_area_struct *vma, pmd_t *pmd, | |
b56a2d8a | 1946 | unsigned long addr, unsigned long end, |
10a9c496 | 1947 | unsigned int type) |
1da177e4 | 1948 | { |
d850fa72 | 1949 | pte_t *pte = NULL; |
b56a2d8a | 1950 | struct swap_info_struct *si; |
1da177e4 | 1951 | |
b56a2d8a | 1952 | si = swap_info[type]; |
1da177e4 | 1953 | do { |
f102cd8b MWO |
1954 | struct folio *folio; |
1955 | unsigned long offset; | |
3f79b187 | 1956 | unsigned char swp_count; |
d850fa72 HD |
1957 | swp_entry_t entry; |
1958 | int ret; | |
c33c7948 | 1959 | pte_t ptent; |
d850fa72 HD |
1960 | |
1961 | if (!pte++) { | |
1962 | pte = pte_offset_map(pmd, addr); | |
1963 | if (!pte) | |
1964 | break; | |
1965 | } | |
f102cd8b | 1966 | |
c33c7948 | 1967 | ptent = ptep_get_lockless(pte); |
f102cd8b | 1968 | |
c33c7948 | 1969 | if (!is_swap_pte(ptent)) |
b56a2d8a VRP |
1970 | continue; |
1971 | ||
c33c7948 | 1972 | entry = pte_to_swp_entry(ptent); |
b56a2d8a VRP |
1973 | if (swp_type(entry) != type) |
1974 | continue; | |
1975 | ||
1976 | offset = swp_offset(entry); | |
b56a2d8a | 1977 | pte_unmap(pte); |
d850fa72 HD |
1978 | pte = NULL; |
1979 | ||
f102cd8b MWO |
1980 | folio = swap_cache_get_folio(entry, vma, addr); |
1981 | if (!folio) { | |
1982 | struct page *page; | |
8c63ca5b WD |
1983 | struct vm_fault vmf = { |
1984 | .vma = vma, | |
1985 | .address = addr, | |
824ddc60 | 1986 | .real_address = addr, |
8c63ca5b WD |
1987 | .pmd = pmd, |
1988 | }; | |
1989 | ||
ebc5951e AR |
1990 | page = swapin_readahead(entry, GFP_HIGHUSER_MOVABLE, |
1991 | &vmf); | |
f102cd8b MWO |
1992 | if (page) |
1993 | folio = page_folio(page); | |
ebc5951e | 1994 | } |
f102cd8b | 1995 | if (!folio) { |
3f79b187 KS |
1996 | swp_count = READ_ONCE(si->swap_map[offset]); |
1997 | if (swp_count == 0 || swp_count == SWAP_MAP_BAD) | |
d850fa72 | 1998 | continue; |
b56a2d8a VRP |
1999 | return -ENOMEM; |
2000 | } | |
2001 | ||
f102cd8b MWO |
2002 | folio_lock(folio); |
2003 | folio_wait_writeback(folio); | |
2004 | ret = unuse_pte(vma, pmd, addr, entry, folio); | |
b56a2d8a | 2005 | if (ret < 0) { |
f102cd8b MWO |
2006 | folio_unlock(folio); |
2007 | folio_put(folio); | |
d850fa72 | 2008 | return ret; |
b56a2d8a VRP |
2009 | } |
2010 | ||
f102cd8b MWO |
2011 | folio_free_swap(folio); |
2012 | folio_unlock(folio); | |
2013 | folio_put(folio); | |
d850fa72 | 2014 | } while (addr += PAGE_SIZE, addr != end); |
b56a2d8a | 2015 | |
d850fa72 HD |
2016 | if (pte) |
2017 | pte_unmap(pte); | |
2018 | return 0; | |
1da177e4 LT |
2019 | } |
2020 | ||
2021 | static inline int unuse_pmd_range(struct vm_area_struct *vma, pud_t *pud, | |
2022 | unsigned long addr, unsigned long end, | |
10a9c496 | 2023 | unsigned int type) |
1da177e4 LT |
2024 | { |
2025 | pmd_t *pmd; | |
2026 | unsigned long next; | |
8a9f3ccd | 2027 | int ret; |
1da177e4 LT |
2028 | |
2029 | pmd = pmd_offset(pud, addr); | |
2030 | do { | |
dc644a07 | 2031 | cond_resched(); |
1da177e4 | 2032 | next = pmd_addr_end(addr, end); |
10a9c496 | 2033 | ret = unuse_pte_range(vma, pmd, addr, next, type); |
8a9f3ccd BS |
2034 | if (ret) |
2035 | return ret; | |
1da177e4 LT |
2036 | } while (pmd++, addr = next, addr != end); |
2037 | return 0; | |
2038 | } | |
2039 | ||
c2febafc | 2040 | static inline int unuse_pud_range(struct vm_area_struct *vma, p4d_t *p4d, |
1da177e4 | 2041 | unsigned long addr, unsigned long end, |
10a9c496 | 2042 | unsigned int type) |
1da177e4 LT |
2043 | { |
2044 | pud_t *pud; | |
2045 | unsigned long next; | |
8a9f3ccd | 2046 | int ret; |
1da177e4 | 2047 | |
c2febafc | 2048 | pud = pud_offset(p4d, addr); |
1da177e4 LT |
2049 | do { |
2050 | next = pud_addr_end(addr, end); | |
2051 | if (pud_none_or_clear_bad(pud)) | |
2052 | continue; | |
10a9c496 | 2053 | ret = unuse_pmd_range(vma, pud, addr, next, type); |
8a9f3ccd BS |
2054 | if (ret) |
2055 | return ret; | |
1da177e4 LT |
2056 | } while (pud++, addr = next, addr != end); |
2057 | return 0; | |
2058 | } | |
2059 | ||
c2febafc KS |
2060 | static inline int unuse_p4d_range(struct vm_area_struct *vma, pgd_t *pgd, |
2061 | unsigned long addr, unsigned long end, | |
10a9c496 | 2062 | unsigned int type) |
c2febafc KS |
2063 | { |
2064 | p4d_t *p4d; | |
2065 | unsigned long next; | |
2066 | int ret; | |
2067 | ||
2068 | p4d = p4d_offset(pgd, addr); | |
2069 | do { | |
2070 | next = p4d_addr_end(addr, end); | |
2071 | if (p4d_none_or_clear_bad(p4d)) | |
2072 | continue; | |
10a9c496 | 2073 | ret = unuse_pud_range(vma, p4d, addr, next, type); |
c2febafc KS |
2074 | if (ret) |
2075 | return ret; | |
2076 | } while (p4d++, addr = next, addr != end); | |
2077 | return 0; | |
2078 | } | |
2079 | ||
10a9c496 | 2080 | static int unuse_vma(struct vm_area_struct *vma, unsigned int type) |
1da177e4 LT |
2081 | { |
2082 | pgd_t *pgd; | |
2083 | unsigned long addr, end, next; | |
8a9f3ccd | 2084 | int ret; |
1da177e4 | 2085 | |
b56a2d8a VRP |
2086 | addr = vma->vm_start; |
2087 | end = vma->vm_end; | |
1da177e4 LT |
2088 | |
2089 | pgd = pgd_offset(vma->vm_mm, addr); | |
2090 | do { | |
2091 | next = pgd_addr_end(addr, end); | |
2092 | if (pgd_none_or_clear_bad(pgd)) | |
2093 | continue; | |
10a9c496 | 2094 | ret = unuse_p4d_range(vma, pgd, addr, next, type); |
8a9f3ccd BS |
2095 | if (ret) |
2096 | return ret; | |
1da177e4 LT |
2097 | } while (pgd++, addr = next, addr != end); |
2098 | return 0; | |
2099 | } | |
2100 | ||
10a9c496 | 2101 | static int unuse_mm(struct mm_struct *mm, unsigned int type) |
1da177e4 LT |
2102 | { |
2103 | struct vm_area_struct *vma; | |
8a9f3ccd | 2104 | int ret = 0; |
208c09db | 2105 | VMA_ITERATOR(vmi, mm, 0); |
1da177e4 | 2106 | |
d8ed45c5 | 2107 | mmap_read_lock(mm); |
208c09db | 2108 | for_each_vma(vmi, vma) { |
b56a2d8a | 2109 | if (vma->anon_vma) { |
10a9c496 | 2110 | ret = unuse_vma(vma, type); |
b56a2d8a VRP |
2111 | if (ret) |
2112 | break; | |
2113 | } | |
208c09db | 2114 | |
dc644a07 | 2115 | cond_resched(); |
1da177e4 | 2116 | } |
d8ed45c5 | 2117 | mmap_read_unlock(mm); |
b56a2d8a | 2118 | return ret; |
1da177e4 LT |
2119 | } |
2120 | ||
2121 | /* | |
3c3115ad ML |
2122 | * Scan swap_map from current position to next entry still in use. |
2123 | * Return 0 if there are no inuse entries after prev till end of | |
2124 | * the map. | |
1da177e4 | 2125 | */ |
6eb396dc | 2126 | static unsigned int find_next_to_unuse(struct swap_info_struct *si, |
10a9c496 | 2127 | unsigned int prev) |
1da177e4 | 2128 | { |
b56a2d8a | 2129 | unsigned int i; |
8d69aaee | 2130 | unsigned char count; |
1da177e4 LT |
2131 | |
2132 | /* | |
5d337b91 | 2133 | * No need for swap_lock here: we're just looking |
1da177e4 LT |
2134 | * for whether an entry is in use, not modifying it; false |
2135 | * hits are okay, and sys_swapoff() has already prevented new | |
5d337b91 | 2136 | * allocations from this area (while holding swap_lock). |
1da177e4 | 2137 | */ |
b56a2d8a | 2138 | for (i = prev + 1; i < si->max; i++) { |
4db0c3c2 | 2139 | count = READ_ONCE(si->swap_map[i]); |
355cfa73 | 2140 | if (count && swap_count(count) != SWAP_MAP_BAD) |
10a9c496 | 2141 | break; |
dc644a07 HD |
2142 | if ((i % LATENCY_LIMIT) == 0) |
2143 | cond_resched(); | |
1da177e4 | 2144 | } |
b56a2d8a VRP |
2145 | |
2146 | if (i == si->max) | |
2147 | i = 0; | |
2148 | ||
1da177e4 LT |
2149 | return i; |
2150 | } | |
2151 | ||
10a9c496 | 2152 | static int try_to_unuse(unsigned int type) |
1da177e4 | 2153 | { |
b56a2d8a VRP |
2154 | struct mm_struct *prev_mm; |
2155 | struct mm_struct *mm; | |
2156 | struct list_head *p; | |
2157 | int retval = 0; | |
efa90a98 | 2158 | struct swap_info_struct *si = swap_info[type]; |
000085b9 | 2159 | struct folio *folio; |
1da177e4 | 2160 | swp_entry_t entry; |
b56a2d8a | 2161 | unsigned int i; |
1da177e4 | 2162 | |
21820948 | 2163 | if (!READ_ONCE(si->inuse_pages)) |
64cf264c | 2164 | goto success; |
1da177e4 | 2165 | |
b56a2d8a | 2166 | retry: |
10a9c496 | 2167 | retval = shmem_unuse(type); |
b56a2d8a | 2168 | if (retval) |
10a9c496 | 2169 | return retval; |
b56a2d8a VRP |
2170 | |
2171 | prev_mm = &init_mm; | |
2172 | mmget(prev_mm); | |
2173 | ||
2174 | spin_lock(&mmlist_lock); | |
2175 | p = &init_mm.mmlist; | |
21820948 | 2176 | while (READ_ONCE(si->inuse_pages) && |
64165b1a HD |
2177 | !signal_pending(current) && |
2178 | (p = p->next) != &init_mm.mmlist) { | |
1da177e4 | 2179 | |
b56a2d8a VRP |
2180 | mm = list_entry(p, struct mm_struct, mmlist); |
2181 | if (!mmget_not_zero(mm)) | |
2182 | continue; | |
2183 | spin_unlock(&mmlist_lock); | |
2184 | mmput(prev_mm); | |
2185 | prev_mm = mm; | |
10a9c496 | 2186 | retval = unuse_mm(mm, type); |
b56a2d8a VRP |
2187 | if (retval) { |
2188 | mmput(prev_mm); | |
10a9c496 | 2189 | return retval; |
1da177e4 LT |
2190 | } |
2191 | ||
2192 | /* | |
b56a2d8a VRP |
2193 | * Make sure that we aren't completely killing |
2194 | * interactive performance. | |
1da177e4 | 2195 | */ |
b56a2d8a VRP |
2196 | cond_resched(); |
2197 | spin_lock(&mmlist_lock); | |
2198 | } | |
2199 | spin_unlock(&mmlist_lock); | |
1da177e4 | 2200 | |
b56a2d8a | 2201 | mmput(prev_mm); |
1da177e4 | 2202 | |
b56a2d8a | 2203 | i = 0; |
21820948 | 2204 | while (READ_ONCE(si->inuse_pages) && |
64165b1a | 2205 | !signal_pending(current) && |
10a9c496 | 2206 | (i = find_next_to_unuse(si, i)) != 0) { |
1da177e4 | 2207 | |
b56a2d8a | 2208 | entry = swp_entry(type, i); |
7aad25b4 | 2209 | folio = filemap_get_folio(swap_address_space(entry), swap_cache_index(entry)); |
66dabbb6 | 2210 | if (IS_ERR(folio)) |
b56a2d8a | 2211 | continue; |
68bdc8d6 HD |
2212 | |
2213 | /* | |
000085b9 MWO |
2214 | * It is conceivable that a racing task removed this folio from |
2215 | * swap cache just before we acquired the page lock. The folio | |
b56a2d8a | 2216 | * might even be back in swap cache on another swap area. But |
000085b9 | 2217 | * that is okay, folio_free_swap() only removes stale folios. |
1da177e4 | 2218 | */ |
000085b9 MWO |
2219 | folio_lock(folio); |
2220 | folio_wait_writeback(folio); | |
2221 | folio_free_swap(folio); | |
2222 | folio_unlock(folio); | |
2223 | folio_put(folio); | |
1da177e4 LT |
2224 | } |
2225 | ||
b56a2d8a VRP |
2226 | /* |
2227 | * Lets check again to see if there are still swap entries in the map. | |
2228 | * If yes, we would need to do retry the unuse logic again. | |
2229 | * Under global memory pressure, swap entries can be reinserted back | |
2230 | * into process space after the mmlist loop above passes over them. | |
dd862deb | 2231 | * |
e2e3fdc7 MWO |
2232 | * Limit the number of retries? No: when mmget_not_zero() |
2233 | * above fails, that mm is likely to be freeing swap from | |
2234 | * exit_mmap(), which proceeds at its own independent pace; | |
2235 | * and even shmem_writepage() could have been preempted after | |
2236 | * folio_alloc_swap(), temporarily hiding that swap. It's easy | |
2237 | * and robust (though cpu-intensive) just to keep retrying. | |
b56a2d8a | 2238 | */ |
21820948 | 2239 | if (READ_ONCE(si->inuse_pages)) { |
64165b1a HD |
2240 | if (!signal_pending(current)) |
2241 | goto retry; | |
10a9c496 | 2242 | return -EINTR; |
64165b1a | 2243 | } |
10a9c496 | 2244 | |
64cf264c YA |
2245 | success: |
2246 | /* | |
2247 | * Make sure that further cleanups after try_to_unuse() returns happen | |
2248 | * after swap_range_free() reduces si->inuse_pages to 0. | |
2249 | */ | |
2250 | smp_mb(); | |
10a9c496 | 2251 | return 0; |
1da177e4 LT |
2252 | } |
2253 | ||
2254 | /* | |
5d337b91 HD |
2255 | * After a successful try_to_unuse, if no swap is now in use, we know |
2256 | * we can empty the mmlist. swap_lock must be held on entry and exit. | |
2257 | * Note that mmlist_lock nests inside swap_lock, and an mm must be | |
1da177e4 LT |
2258 | * added to the mmlist just after page_duplicate - before would be racy. |
2259 | */ | |
2260 | static void drain_mmlist(void) | |
2261 | { | |
2262 | struct list_head *p, *next; | |
efa90a98 | 2263 | unsigned int type; |
1da177e4 | 2264 | |
efa90a98 HD |
2265 | for (type = 0; type < nr_swapfiles; type++) |
2266 | if (swap_info[type]->inuse_pages) | |
1da177e4 LT |
2267 | return; |
2268 | spin_lock(&mmlist_lock); | |
2269 | list_for_each_safe(p, next, &init_mm.mmlist) | |
2270 | list_del_init(p); | |
2271 | spin_unlock(&mmlist_lock); | |
2272 | } | |
2273 | ||
1da177e4 LT |
2274 | /* |
2275 | * Free all of a swapdev's extent information | |
2276 | */ | |
2277 | static void destroy_swap_extents(struct swap_info_struct *sis) | |
2278 | { | |
4efaceb1 AL |
2279 | while (!RB_EMPTY_ROOT(&sis->swap_extent_root)) { |
2280 | struct rb_node *rb = sis->swap_extent_root.rb_node; | |
2281 | struct swap_extent *se = rb_entry(rb, struct swap_extent, rb_node); | |
1da177e4 | 2282 | |
4efaceb1 | 2283 | rb_erase(rb, &sis->swap_extent_root); |
1da177e4 LT |
2284 | kfree(se); |
2285 | } | |
62c230bc | 2286 | |
bc4ae27d | 2287 | if (sis->flags & SWP_ACTIVATED) { |
62c230bc MG |
2288 | struct file *swap_file = sis->swap_file; |
2289 | struct address_space *mapping = swap_file->f_mapping; | |
2290 | ||
bc4ae27d OS |
2291 | sis->flags &= ~SWP_ACTIVATED; |
2292 | if (mapping->a_ops->swap_deactivate) | |
2293 | mapping->a_ops->swap_deactivate(swap_file); | |
62c230bc | 2294 | } |
1da177e4 LT |
2295 | } |
2296 | ||
2297 | /* | |
2298 | * Add a block range (and the corresponding page range) into this swapdev's | |
4efaceb1 | 2299 | * extent tree. |
1da177e4 | 2300 | * |
11d31886 | 2301 | * This function rather assumes that it is called in ascending page order. |
1da177e4 | 2302 | */ |
a509bc1a | 2303 | int |
1da177e4 LT |
2304 | add_swap_extent(struct swap_info_struct *sis, unsigned long start_page, |
2305 | unsigned long nr_pages, sector_t start_block) | |
2306 | { | |
4efaceb1 | 2307 | struct rb_node **link = &sis->swap_extent_root.rb_node, *parent = NULL; |
1da177e4 LT |
2308 | struct swap_extent *se; |
2309 | struct swap_extent *new_se; | |
4efaceb1 AL |
2310 | |
2311 | /* | |
2312 | * place the new node at the right most since the | |
2313 | * function is called in ascending page order. | |
2314 | */ | |
2315 | while (*link) { | |
2316 | parent = *link; | |
2317 | link = &parent->rb_right; | |
2318 | } | |
2319 | ||
2320 | if (parent) { | |
2321 | se = rb_entry(parent, struct swap_extent, rb_node); | |
11d31886 HD |
2322 | BUG_ON(se->start_page + se->nr_pages != start_page); |
2323 | if (se->start_block + se->nr_pages == start_block) { | |
1da177e4 LT |
2324 | /* Merge it */ |
2325 | se->nr_pages += nr_pages; | |
2326 | return 0; | |
2327 | } | |
1da177e4 LT |
2328 | } |
2329 | ||
4efaceb1 | 2330 | /* No merge, insert a new extent. */ |
1da177e4 LT |
2331 | new_se = kmalloc(sizeof(*se), GFP_KERNEL); |
2332 | if (new_se == NULL) | |
2333 | return -ENOMEM; | |
2334 | new_se->start_page = start_page; | |
2335 | new_se->nr_pages = nr_pages; | |
2336 | new_se->start_block = start_block; | |
2337 | ||
4efaceb1 AL |
2338 | rb_link_node(&new_se->rb_node, parent, link); |
2339 | rb_insert_color(&new_se->rb_node, &sis->swap_extent_root); | |
53092a74 | 2340 | return 1; |
1da177e4 | 2341 | } |
aa8aa8a3 | 2342 | EXPORT_SYMBOL_GPL(add_swap_extent); |
1da177e4 LT |
2343 | |
2344 | /* | |
2345 | * A `swap extent' is a simple thing which maps a contiguous range of pages | |
ff351f4b | 2346 | * onto a contiguous range of disk blocks. A rbtree of swap extents is |
c9bdf768 | 2347 | * built at swapon time and is then used at swap_writepage/swap_read_folio |
1da177e4 LT |
2348 | * time for locating where on disk a page belongs. |
2349 | * | |
2350 | * If the swapfile is an S_ISBLK block device, a single extent is installed. | |
2351 | * This is done so that the main operating code can treat S_ISBLK and S_ISREG | |
2352 | * swap files identically. | |
2353 | * | |
2354 | * Whether the swapdev is an S_ISREG file or an S_ISBLK blockdev, the swap | |
ff351f4b | 2355 | * extent rbtree operates in PAGE_SIZE disk blocks. Both S_ISREG and S_ISBLK |
1da177e4 LT |
2356 | * swapfiles are handled *identically* after swapon time. |
2357 | * | |
2358 | * For S_ISREG swapfiles, setup_swap_extents() will walk all the file's blocks | |
ff351f4b ML |
2359 | * and will parse them into a rbtree, in PAGE_SIZE chunks. If some stray |
2360 | * blocks are found which do not fall within the PAGE_SIZE alignment | |
1da177e4 LT |
2361 | * requirements, they are simply tossed out - we will never use those blocks |
2362 | * for swapping. | |
2363 | * | |
1638045c DW |
2364 | * For all swap devices we set S_SWAPFILE across the life of the swapon. This |
2365 | * prevents users from writing to the swap device, which will corrupt memory. | |
1da177e4 LT |
2366 | * |
2367 | * The amount of disk space which a single swap extent represents varies. | |
2368 | * Typically it is in the 1-4 megabyte range. So we can have hundreds of | |
ff351f4b | 2369 | * extents in the rbtree. - akpm. |
1da177e4 | 2370 | */ |
53092a74 | 2371 | static int setup_swap_extents(struct swap_info_struct *sis, sector_t *span) |
1da177e4 | 2372 | { |
62c230bc MG |
2373 | struct file *swap_file = sis->swap_file; |
2374 | struct address_space *mapping = swap_file->f_mapping; | |
2375 | struct inode *inode = mapping->host; | |
1da177e4 LT |
2376 | int ret; |
2377 | ||
1da177e4 LT |
2378 | if (S_ISBLK(inode->i_mode)) { |
2379 | ret = add_swap_extent(sis, 0, sis->max, 0); | |
53092a74 | 2380 | *span = sis->pages; |
a509bc1a | 2381 | return ret; |
1da177e4 LT |
2382 | } |
2383 | ||
62c230bc | 2384 | if (mapping->a_ops->swap_activate) { |
a509bc1a | 2385 | ret = mapping->a_ops->swap_activate(sis, swap_file, span); |
4b60c0ff N |
2386 | if (ret < 0) |
2387 | return ret; | |
2388 | sis->flags |= SWP_ACTIVATED; | |
e1209d3a N |
2389 | if ((sis->flags & SWP_FS_OPS) && |
2390 | sio_pool_init() != 0) { | |
2391 | destroy_swap_extents(sis); | |
2392 | return -ENOMEM; | |
62c230bc | 2393 | } |
a509bc1a | 2394 | return ret; |
62c230bc MG |
2395 | } |
2396 | ||
a509bc1a | 2397 | return generic_swapfile_activate(sis, swap_file, span); |
1da177e4 LT |
2398 | } |
2399 | ||
a2468cc9 AL |
2400 | static int swap_node(struct swap_info_struct *p) |
2401 | { | |
2402 | struct block_device *bdev; | |
2403 | ||
2404 | if (p->bdev) | |
2405 | bdev = p->bdev; | |
2406 | else | |
2407 | bdev = p->swap_file->f_inode->i_sb->s_bdev; | |
2408 | ||
2409 | return bdev ? bdev->bd_disk->node_id : NUMA_NO_NODE; | |
2410 | } | |
2411 | ||
eb085574 HY |
2412 | static void setup_swap_info(struct swap_info_struct *p, int prio, |
2413 | unsigned char *swap_map, | |
2414 | struct swap_cluster_info *cluster_info) | |
40531542 | 2415 | { |
a2468cc9 AL |
2416 | int i; |
2417 | ||
40531542 CEB |
2418 | if (prio >= 0) |
2419 | p->prio = prio; | |
2420 | else | |
2421 | p->prio = --least_priority; | |
18ab4d4c DS |
2422 | /* |
2423 | * the plist prio is negated because plist ordering is | |
2424 | * low-to-high, while swap ordering is high-to-low | |
2425 | */ | |
2426 | p->list.prio = -p->prio; | |
a2468cc9 AL |
2427 | for_each_node(i) { |
2428 | if (p->prio >= 0) | |
2429 | p->avail_lists[i].prio = -p->prio; | |
2430 | else { | |
2431 | if (swap_node(p) == i) | |
2432 | p->avail_lists[i].prio = 1; | |
2433 | else | |
2434 | p->avail_lists[i].prio = -p->prio; | |
2435 | } | |
2436 | } | |
40531542 | 2437 | p->swap_map = swap_map; |
2a8f9449 | 2438 | p->cluster_info = cluster_info; |
eb085574 HY |
2439 | } |
2440 | ||
2441 | static void _enable_swap_info(struct swap_info_struct *p) | |
2442 | { | |
63d8620e | 2443 | p->flags |= SWP_WRITEOK; |
ec8acf20 | 2444 | atomic_long_add(p->pages, &nr_swap_pages); |
40531542 CEB |
2445 | total_swap_pages += p->pages; |
2446 | ||
adfab836 | 2447 | assert_spin_locked(&swap_lock); |
adfab836 | 2448 | /* |
18ab4d4c DS |
2449 | * both lists are plists, and thus priority ordered. |
2450 | * swap_active_head needs to be priority ordered for swapoff(), | |
2451 | * which on removal of any swap_info_struct with an auto-assigned | |
2452 | * (i.e. negative) priority increments the auto-assigned priority | |
2453 | * of any lower-priority swap_info_structs. | |
e2e3fdc7 | 2454 | * swap_avail_head needs to be priority ordered for folio_alloc_swap(), |
18ab4d4c DS |
2455 | * which allocates swap pages from the highest available priority |
2456 | * swap_info_struct. | |
adfab836 | 2457 | */ |
18ab4d4c | 2458 | plist_add(&p->list, &swap_active_head); |
c70699e5 MW |
2459 | |
2460 | /* add to available list iff swap device is not full */ | |
2461 | if (p->highest_bit) | |
2462 | add_to_avail_list(p); | |
cf0cac0a CEB |
2463 | } |
2464 | ||
2465 | static void enable_swap_info(struct swap_info_struct *p, int prio, | |
2466 | unsigned char *swap_map, | |
42c06a0e | 2467 | struct swap_cluster_info *cluster_info) |
cf0cac0a CEB |
2468 | { |
2469 | spin_lock(&swap_lock); | |
ec8acf20 | 2470 | spin_lock(&p->lock); |
eb085574 HY |
2471 | setup_swap_info(p, prio, swap_map, cluster_info); |
2472 | spin_unlock(&p->lock); | |
2473 | spin_unlock(&swap_lock); | |
2474 | /* | |
63d8620e | 2475 | * Finished initializing swap device, now it's safe to reference it. |
eb085574 | 2476 | */ |
63d8620e | 2477 | percpu_ref_resurrect(&p->users); |
eb085574 HY |
2478 | spin_lock(&swap_lock); |
2479 | spin_lock(&p->lock); | |
2480 | _enable_swap_info(p); | |
ec8acf20 | 2481 | spin_unlock(&p->lock); |
cf0cac0a CEB |
2482 | spin_unlock(&swap_lock); |
2483 | } | |
2484 | ||
2485 | static void reinsert_swap_info(struct swap_info_struct *p) | |
2486 | { | |
2487 | spin_lock(&swap_lock); | |
ec8acf20 | 2488 | spin_lock(&p->lock); |
eb085574 HY |
2489 | setup_swap_info(p, p->prio, p->swap_map, p->cluster_info); |
2490 | _enable_swap_info(p); | |
ec8acf20 | 2491 | spin_unlock(&p->lock); |
40531542 CEB |
2492 | spin_unlock(&swap_lock); |
2493 | } | |
2494 | ||
80e75021 KW |
2495 | static bool __has_usable_swap(void) |
2496 | { | |
2497 | return !plist_head_empty(&swap_active_head); | |
2498 | } | |
2499 | ||
67afa38e TC |
2500 | bool has_usable_swap(void) |
2501 | { | |
80e75021 | 2502 | bool ret; |
67afa38e TC |
2503 | |
2504 | spin_lock(&swap_lock); | |
80e75021 | 2505 | ret = __has_usable_swap(); |
67afa38e TC |
2506 | spin_unlock(&swap_lock); |
2507 | return ret; | |
2508 | } | |
2509 | ||
c4ea37c2 | 2510 | SYSCALL_DEFINE1(swapoff, const char __user *, specialfile) |
1da177e4 | 2511 | { |
73c34b6a | 2512 | struct swap_info_struct *p = NULL; |
8d69aaee | 2513 | unsigned char *swap_map; |
2a8f9449 | 2514 | struct swap_cluster_info *cluster_info; |
1da177e4 LT |
2515 | struct file *swap_file, *victim; |
2516 | struct address_space *mapping; | |
2517 | struct inode *inode; | |
91a27b2a | 2518 | struct filename *pathname; |
adfab836 | 2519 | int err, found = 0; |
886bb7e9 | 2520 | |
1da177e4 LT |
2521 | if (!capable(CAP_SYS_ADMIN)) |
2522 | return -EPERM; | |
2523 | ||
191c5424 AV |
2524 | BUG_ON(!current->mm); |
2525 | ||
1da177e4 | 2526 | pathname = getname(specialfile); |
1da177e4 | 2527 | if (IS_ERR(pathname)) |
f58b59c1 | 2528 | return PTR_ERR(pathname); |
1da177e4 | 2529 | |
669abf4e | 2530 | victim = file_open_name(pathname, O_RDWR|O_LARGEFILE, 0); |
1da177e4 LT |
2531 | err = PTR_ERR(victim); |
2532 | if (IS_ERR(victim)) | |
2533 | goto out; | |
2534 | ||
2535 | mapping = victim->f_mapping; | |
5d337b91 | 2536 | spin_lock(&swap_lock); |
18ab4d4c | 2537 | plist_for_each_entry(p, &swap_active_head, list) { |
22c6f8fd | 2538 | if (p->flags & SWP_WRITEOK) { |
adfab836 DS |
2539 | if (p->swap_file->f_mapping == mapping) { |
2540 | found = 1; | |
1da177e4 | 2541 | break; |
adfab836 | 2542 | } |
1da177e4 | 2543 | } |
1da177e4 | 2544 | } |
adfab836 | 2545 | if (!found) { |
1da177e4 | 2546 | err = -EINVAL; |
5d337b91 | 2547 | spin_unlock(&swap_lock); |
1da177e4 LT |
2548 | goto out_dput; |
2549 | } | |
191c5424 | 2550 | if (!security_vm_enough_memory_mm(current->mm, p->pages)) |
1da177e4 LT |
2551 | vm_unacct_memory(p->pages); |
2552 | else { | |
2553 | err = -ENOMEM; | |
5d337b91 | 2554 | spin_unlock(&swap_lock); |
1da177e4 LT |
2555 | goto out_dput; |
2556 | } | |
ec8acf20 | 2557 | spin_lock(&p->lock); |
6fe7d6b9 | 2558 | del_from_avail_list(p); |
78ecba08 | 2559 | if (p->prio < 0) { |
adfab836 | 2560 | struct swap_info_struct *si = p; |
a2468cc9 | 2561 | int nid; |
adfab836 | 2562 | |
18ab4d4c | 2563 | plist_for_each_entry_continue(si, &swap_active_head, list) { |
adfab836 | 2564 | si->prio++; |
18ab4d4c | 2565 | si->list.prio--; |
a2468cc9 AL |
2566 | for_each_node(nid) { |
2567 | if (si->avail_lists[nid].prio != 1) | |
2568 | si->avail_lists[nid].prio--; | |
2569 | } | |
adfab836 | 2570 | } |
78ecba08 HD |
2571 | least_priority++; |
2572 | } | |
18ab4d4c | 2573 | plist_del(&p->list, &swap_active_head); |
ec8acf20 | 2574 | atomic_long_sub(p->pages, &nr_swap_pages); |
1da177e4 LT |
2575 | total_swap_pages -= p->pages; |
2576 | p->flags &= ~SWP_WRITEOK; | |
ec8acf20 | 2577 | spin_unlock(&p->lock); |
5d337b91 | 2578 | spin_unlock(&swap_lock); |
fb4f88dc | 2579 | |
039939a6 TC |
2580 | disable_swap_slots_cache_lock(); |
2581 | ||
e1e12d2f | 2582 | set_current_oom_origin(); |
10a9c496 | 2583 | err = try_to_unuse(p->type); |
e1e12d2f | 2584 | clear_current_oom_origin(); |
1da177e4 | 2585 | |
1da177e4 LT |
2586 | if (err) { |
2587 | /* re-insert swap space back into swap_list */ | |
cf0cac0a | 2588 | reinsert_swap_info(p); |
039939a6 | 2589 | reenable_swap_slots_cache_unlock(); |
1da177e4 LT |
2590 | goto out_dput; |
2591 | } | |
52b7efdb | 2592 | |
039939a6 TC |
2593 | reenable_swap_slots_cache_unlock(); |
2594 | ||
eb085574 | 2595 | /* |
63d8620e | 2596 | * Wait for swap operations protected by get/put_swap_device() |
d4a34d7f HY |
2597 | * to complete. Because of synchronize_rcu() here, all swap |
2598 | * operations protected by RCU reader side lock (including any | |
2599 | * spinlock) will be waited too. This makes it easy to | |
2600 | * prevent folio_test_swapcache() and the following swap cache | |
2601 | * operations from racing with swapoff. | |
eb085574 | 2602 | */ |
63d8620e | 2603 | percpu_ref_kill(&p->users); |
eb085574 | 2604 | synchronize_rcu(); |
63d8620e | 2605 | wait_for_completion(&p->comp); |
eb085574 | 2606 | |
815c2c54 SL |
2607 | flush_work(&p->discard_work); |
2608 | ||
5d337b91 | 2609 | destroy_swap_extents(p); |
570a335b HD |
2610 | if (p->flags & SWP_CONTINUED) |
2611 | free_swap_count_continuations(p); | |
2612 | ||
10f0d2a5 | 2613 | if (!p->bdev || !bdev_nonrot(p->bdev)) |
81a0298b HY |
2614 | atomic_dec(&nr_rotate_swap); |
2615 | ||
fc0abb14 | 2616 | mutex_lock(&swapon_mutex); |
5d337b91 | 2617 | spin_lock(&swap_lock); |
ec8acf20 | 2618 | spin_lock(&p->lock); |
5d337b91 HD |
2619 | drain_mmlist(); |
2620 | ||
bb243f7d | 2621 | /* wait for anyone still in scan_swap_map_slots */ |
52b7efdb HD |
2622 | p->highest_bit = 0; /* cuts scans short */ |
2623 | while (p->flags >= SWP_SCANNING) { | |
ec8acf20 | 2624 | spin_unlock(&p->lock); |
5d337b91 | 2625 | spin_unlock(&swap_lock); |
13e4b57f | 2626 | schedule_timeout_uninterruptible(1); |
5d337b91 | 2627 | spin_lock(&swap_lock); |
ec8acf20 | 2628 | spin_lock(&p->lock); |
52b7efdb | 2629 | } |
52b7efdb | 2630 | |
1da177e4 LT |
2631 | swap_file = p->swap_file; |
2632 | p->swap_file = NULL; | |
2633 | p->max = 0; | |
2634 | swap_map = p->swap_map; | |
2635 | p->swap_map = NULL; | |
2a8f9449 SL |
2636 | cluster_info = p->cluster_info; |
2637 | p->cluster_info = NULL; | |
ec8acf20 | 2638 | spin_unlock(&p->lock); |
5d337b91 | 2639 | spin_unlock(&swap_lock); |
8a84802e | 2640 | arch_swap_invalidate_area(p->type); |
42c06a0e | 2641 | zswap_swapoff(p->type); |
fc0abb14 | 2642 | mutex_unlock(&swapon_mutex); |
ebc2a1a6 SL |
2643 | free_percpu(p->percpu_cluster); |
2644 | p->percpu_cluster = NULL; | |
49070588 HY |
2645 | free_percpu(p->cluster_next_cpu); |
2646 | p->cluster_next_cpu = NULL; | |
1da177e4 | 2647 | vfree(swap_map); |
54f180d3 | 2648 | kvfree(cluster_info); |
2de1a7e4 | 2649 | /* Destroy swap account information */ |
adfab836 | 2650 | swap_cgroup_swapoff(p->type); |
4b3ef9da | 2651 | exit_swap_address_space(p->type); |
27a7faa0 | 2652 | |
1da177e4 | 2653 | inode = mapping->host; |
1638045c DW |
2654 | |
2655 | inode_lock(inode); | |
2656 | inode->i_flags &= ~S_SWAPFILE; | |
2657 | inode_unlock(inode); | |
1da177e4 | 2658 | filp_close(swap_file, NULL); |
f893ab41 WY |
2659 | |
2660 | /* | |
2661 | * Clear the SWP_USED flag after all resources are freed so that swapon | |
2662 | * can reuse this swap_info in alloc_swap_info() safely. It is ok to | |
2663 | * not hold p->lock after we cleared its SWP_WRITEOK. | |
2664 | */ | |
2665 | spin_lock(&swap_lock); | |
2666 | p->flags = 0; | |
2667 | spin_unlock(&swap_lock); | |
2668 | ||
1da177e4 | 2669 | err = 0; |
66d7dd51 KS |
2670 | atomic_inc(&proc_poll_event); |
2671 | wake_up_interruptible(&proc_poll_wait); | |
1da177e4 LT |
2672 | |
2673 | out_dput: | |
2674 | filp_close(victim, NULL); | |
2675 | out: | |
f58b59c1 | 2676 | putname(pathname); |
1da177e4 LT |
2677 | return err; |
2678 | } | |
2679 | ||
2680 | #ifdef CONFIG_PROC_FS | |
9dd95748 | 2681 | static __poll_t swaps_poll(struct file *file, poll_table *wait) |
66d7dd51 | 2682 | { |
f1514638 | 2683 | struct seq_file *seq = file->private_data; |
66d7dd51 KS |
2684 | |
2685 | poll_wait(file, &proc_poll_wait, wait); | |
2686 | ||
f1514638 KS |
2687 | if (seq->poll_event != atomic_read(&proc_poll_event)) { |
2688 | seq->poll_event = atomic_read(&proc_poll_event); | |
a9a08845 | 2689 | return EPOLLIN | EPOLLRDNORM | EPOLLERR | EPOLLPRI; |
66d7dd51 KS |
2690 | } |
2691 | ||
a9a08845 | 2692 | return EPOLLIN | EPOLLRDNORM; |
66d7dd51 KS |
2693 | } |
2694 | ||
1da177e4 LT |
2695 | /* iterator */ |
2696 | static void *swap_start(struct seq_file *swap, loff_t *pos) | |
2697 | { | |
efa90a98 HD |
2698 | struct swap_info_struct *si; |
2699 | int type; | |
1da177e4 LT |
2700 | loff_t l = *pos; |
2701 | ||
fc0abb14 | 2702 | mutex_lock(&swapon_mutex); |
1da177e4 | 2703 | |
881e4aab SS |
2704 | if (!l) |
2705 | return SEQ_START_TOKEN; | |
2706 | ||
c10d38cc | 2707 | for (type = 0; (si = swap_type_to_swap_info(type)); type++) { |
efa90a98 | 2708 | if (!(si->flags & SWP_USED) || !si->swap_map) |
1da177e4 | 2709 | continue; |
881e4aab | 2710 | if (!--l) |
efa90a98 | 2711 | return si; |
1da177e4 LT |
2712 | } |
2713 | ||
2714 | return NULL; | |
2715 | } | |
2716 | ||
2717 | static void *swap_next(struct seq_file *swap, void *v, loff_t *pos) | |
2718 | { | |
efa90a98 HD |
2719 | struct swap_info_struct *si = v; |
2720 | int type; | |
1da177e4 | 2721 | |
881e4aab | 2722 | if (v == SEQ_START_TOKEN) |
efa90a98 HD |
2723 | type = 0; |
2724 | else | |
2725 | type = si->type + 1; | |
881e4aab | 2726 | |
10c8d69f | 2727 | ++(*pos); |
c10d38cc | 2728 | for (; (si = swap_type_to_swap_info(type)); type++) { |
efa90a98 | 2729 | if (!(si->flags & SWP_USED) || !si->swap_map) |
1da177e4 | 2730 | continue; |
efa90a98 | 2731 | return si; |
1da177e4 LT |
2732 | } |
2733 | ||
2734 | return NULL; | |
2735 | } | |
2736 | ||
2737 | static void swap_stop(struct seq_file *swap, void *v) | |
2738 | { | |
fc0abb14 | 2739 | mutex_unlock(&swapon_mutex); |
1da177e4 LT |
2740 | } |
2741 | ||
2742 | static int swap_show(struct seq_file *swap, void *v) | |
2743 | { | |
efa90a98 | 2744 | struct swap_info_struct *si = v; |
1da177e4 LT |
2745 | struct file *file; |
2746 | int len; | |
642929a2 | 2747 | unsigned long bytes, inuse; |
1da177e4 | 2748 | |
efa90a98 | 2749 | if (si == SEQ_START_TOKEN) { |
68d68ff6 | 2750 | seq_puts(swap, "Filename\t\t\t\tType\t\tSize\t\tUsed\t\tPriority\n"); |
881e4aab SS |
2751 | return 0; |
2752 | } | |
1da177e4 | 2753 | |
00cde042 Z |
2754 | bytes = K(si->pages); |
2755 | inuse = K(READ_ONCE(si->inuse_pages)); | |
6f793940 | 2756 | |
efa90a98 | 2757 | file = si->swap_file; |
2726d566 | 2758 | len = seq_file_path(swap, file, " \t\n\\"); |
642929a2 | 2759 | seq_printf(swap, "%*s%s\t%lu\t%s%lu\t%s%d\n", |
886bb7e9 | 2760 | len < 40 ? 40 - len : 1, " ", |
496ad9aa | 2761 | S_ISBLK(file_inode(file)->i_mode) ? |
1da177e4 | 2762 | "partition" : "file\t", |
6f793940 RD |
2763 | bytes, bytes < 10000000 ? "\t" : "", |
2764 | inuse, inuse < 10000000 ? "\t" : "", | |
efa90a98 | 2765 | si->prio); |
1da177e4 LT |
2766 | return 0; |
2767 | } | |
2768 | ||
15ad7cdc | 2769 | static const struct seq_operations swaps_op = { |
1da177e4 LT |
2770 | .start = swap_start, |
2771 | .next = swap_next, | |
2772 | .stop = swap_stop, | |
2773 | .show = swap_show | |
2774 | }; | |
2775 | ||
2776 | static int swaps_open(struct inode *inode, struct file *file) | |
2777 | { | |
f1514638 | 2778 | struct seq_file *seq; |
66d7dd51 KS |
2779 | int ret; |
2780 | ||
66d7dd51 | 2781 | ret = seq_open(file, &swaps_op); |
f1514638 | 2782 | if (ret) |
66d7dd51 | 2783 | return ret; |
66d7dd51 | 2784 | |
f1514638 KS |
2785 | seq = file->private_data; |
2786 | seq->poll_event = atomic_read(&proc_poll_event); | |
2787 | return 0; | |
1da177e4 LT |
2788 | } |
2789 | ||
97a32539 | 2790 | static const struct proc_ops swaps_proc_ops = { |
d919b33d | 2791 | .proc_flags = PROC_ENTRY_PERMANENT, |
97a32539 AD |
2792 | .proc_open = swaps_open, |
2793 | .proc_read = seq_read, | |
2794 | .proc_lseek = seq_lseek, | |
2795 | .proc_release = seq_release, | |
2796 | .proc_poll = swaps_poll, | |
1da177e4 LT |
2797 | }; |
2798 | ||
2799 | static int __init procswaps_init(void) | |
2800 | { | |
97a32539 | 2801 | proc_create("swaps", 0, NULL, &swaps_proc_ops); |
1da177e4 LT |
2802 | return 0; |
2803 | } | |
2804 | __initcall(procswaps_init); | |
2805 | #endif /* CONFIG_PROC_FS */ | |
2806 | ||
1796316a JB |
2807 | #ifdef MAX_SWAPFILES_CHECK |
2808 | static int __init max_swapfiles_check(void) | |
2809 | { | |
2810 | MAX_SWAPFILES_CHECK(); | |
2811 | return 0; | |
2812 | } | |
2813 | late_initcall(max_swapfiles_check); | |
2814 | #endif | |
2815 | ||
53cbb243 | 2816 | static struct swap_info_struct *alloc_swap_info(void) |
1da177e4 | 2817 | { |
73c34b6a | 2818 | struct swap_info_struct *p; |
b11a76b3 | 2819 | struct swap_info_struct *defer = NULL; |
1da177e4 | 2820 | unsigned int type; |
a2468cc9 | 2821 | int i; |
efa90a98 | 2822 | |
96008744 | 2823 | p = kvzalloc(struct_size(p, avail_lists, nr_node_ids), GFP_KERNEL); |
efa90a98 | 2824 | if (!p) |
53cbb243 | 2825 | return ERR_PTR(-ENOMEM); |
efa90a98 | 2826 | |
63d8620e ML |
2827 | if (percpu_ref_init(&p->users, swap_users_ref_free, |
2828 | PERCPU_REF_INIT_DEAD, GFP_KERNEL)) { | |
2829 | kvfree(p); | |
2830 | return ERR_PTR(-ENOMEM); | |
2831 | } | |
2832 | ||
5d337b91 | 2833 | spin_lock(&swap_lock); |
efa90a98 HD |
2834 | for (type = 0; type < nr_swapfiles; type++) { |
2835 | if (!(swap_info[type]->flags & SWP_USED)) | |
1da177e4 | 2836 | break; |
efa90a98 | 2837 | } |
0697212a | 2838 | if (type >= MAX_SWAPFILES) { |
5d337b91 | 2839 | spin_unlock(&swap_lock); |
63d8620e | 2840 | percpu_ref_exit(&p->users); |
873d7bcf | 2841 | kvfree(p); |
730c0581 | 2842 | return ERR_PTR(-EPERM); |
1da177e4 | 2843 | } |
efa90a98 HD |
2844 | if (type >= nr_swapfiles) { |
2845 | p->type = type; | |
efa90a98 | 2846 | /* |
a4b45114 HY |
2847 | * Publish the swap_info_struct after initializing it. |
2848 | * Note that kvzalloc() above zeroes all its fields. | |
efa90a98 | 2849 | */ |
a4b45114 HY |
2850 | smp_store_release(&swap_info[type], p); /* rcu_assign_pointer() */ |
2851 | nr_swapfiles++; | |
efa90a98 | 2852 | } else { |
b11a76b3 | 2853 | defer = p; |
efa90a98 HD |
2854 | p = swap_info[type]; |
2855 | /* | |
2856 | * Do not memset this entry: a racing procfs swap_next() | |
2857 | * would be relying on p->type to remain valid. | |
2858 | */ | |
2859 | } | |
4efaceb1 | 2860 | p->swap_extent_root = RB_ROOT; |
18ab4d4c | 2861 | plist_node_init(&p->list, 0); |
a2468cc9 AL |
2862 | for_each_node(i) |
2863 | plist_node_init(&p->avail_lists[i], 0); | |
1da177e4 | 2864 | p->flags = SWP_USED; |
5d337b91 | 2865 | spin_unlock(&swap_lock); |
63d8620e ML |
2866 | if (defer) { |
2867 | percpu_ref_exit(&defer->users); | |
2868 | kvfree(defer); | |
2869 | } | |
ec8acf20 | 2870 | spin_lock_init(&p->lock); |
2628bd6f | 2871 | spin_lock_init(&p->cont_lock); |
63d8620e | 2872 | init_completion(&p->comp); |
efa90a98 | 2873 | |
53cbb243 | 2874 | return p; |
53cbb243 CEB |
2875 | } |
2876 | ||
4d0e1e10 CEB |
2877 | static int claim_swapfile(struct swap_info_struct *p, struct inode *inode) |
2878 | { | |
4d0e1e10 | 2879 | if (S_ISBLK(inode->i_mode)) { |
51d908b3 | 2880 | p->bdev = I_BDEV(inode); |
12d2966d NA |
2881 | /* |
2882 | * Zoned block devices contain zones that have a sequential | |
2883 | * write only restriction. Hence zoned block devices are not | |
2884 | * suitable for swapping. Disallow them here. | |
2885 | */ | |
9964e674 | 2886 | if (bdev_is_zoned(p->bdev)) |
12d2966d | 2887 | return -EINVAL; |
4d0e1e10 CEB |
2888 | p->flags |= SWP_BLKDEV; |
2889 | } else if (S_ISREG(inode->i_mode)) { | |
2890 | p->bdev = inode->i_sb->s_bdev; | |
1638045c DW |
2891 | } |
2892 | ||
4d0e1e10 | 2893 | return 0; |
4d0e1e10 CEB |
2894 | } |
2895 | ||
377eeaa8 AK |
2896 | |
2897 | /* | |
2898 | * Find out how many pages are allowed for a single swap device. There | |
2899 | * are two limiting factors: | |
2900 | * 1) the number of bits for the swap offset in the swp_entry_t type, and | |
2901 | * 2) the number of bits in the swap pte, as defined by the different | |
2902 | * architectures. | |
2903 | * | |
2904 | * In order to find the largest possible bit mask, a swap entry with | |
2905 | * swap type 0 and swap offset ~0UL is created, encoded to a swap pte, | |
2906 | * decoded to a swp_entry_t again, and finally the swap offset is | |
2907 | * extracted. | |
2908 | * | |
2909 | * This will mask all the bits from the initial ~0UL mask that can't | |
2910 | * be encoded in either the swp_entry_t or the architecture definition | |
2911 | * of a swap pte. | |
2912 | */ | |
2913 | unsigned long generic_max_swapfile_size(void) | |
2914 | { | |
2915 | return swp_offset(pte_to_swp_entry( | |
2916 | swp_entry_to_pte(swp_entry(0, ~0UL)))) + 1; | |
2917 | } | |
2918 | ||
2919 | /* Can be overridden by an architecture for additional checks. */ | |
be45a490 | 2920 | __weak unsigned long arch_max_swapfile_size(void) |
377eeaa8 AK |
2921 | { |
2922 | return generic_max_swapfile_size(); | |
2923 | } | |
2924 | ||
ca8bd38b CEB |
2925 | static unsigned long read_swap_header(struct swap_info_struct *p, |
2926 | union swap_header *swap_header, | |
2927 | struct inode *inode) | |
2928 | { | |
2929 | int i; | |
2930 | unsigned long maxpages; | |
2931 | unsigned long swapfilepages; | |
d6bbbd29 | 2932 | unsigned long last_page; |
ca8bd38b CEB |
2933 | |
2934 | if (memcmp("SWAPSPACE2", swap_header->magic.magic, 10)) { | |
465c47fd | 2935 | pr_err("Unable to find swap-space signature\n"); |
38719025 | 2936 | return 0; |
ca8bd38b CEB |
2937 | } |
2938 | ||
041711ce | 2939 | /* swap partition endianness hack... */ |
ca8bd38b CEB |
2940 | if (swab32(swap_header->info.version) == 1) { |
2941 | swab32s(&swap_header->info.version); | |
2942 | swab32s(&swap_header->info.last_page); | |
2943 | swab32s(&swap_header->info.nr_badpages); | |
dd111be6 JH |
2944 | if (swap_header->info.nr_badpages > MAX_SWAP_BADPAGES) |
2945 | return 0; | |
ca8bd38b CEB |
2946 | for (i = 0; i < swap_header->info.nr_badpages; i++) |
2947 | swab32s(&swap_header->info.badpages[i]); | |
2948 | } | |
2949 | /* Check the swap header's sub-version */ | |
2950 | if (swap_header->info.version != 1) { | |
465c47fd AM |
2951 | pr_warn("Unable to handle swap header version %d\n", |
2952 | swap_header->info.version); | |
38719025 | 2953 | return 0; |
ca8bd38b CEB |
2954 | } |
2955 | ||
2956 | p->lowest_bit = 1; | |
2957 | p->cluster_next = 1; | |
2958 | p->cluster_nr = 0; | |
2959 | ||
be45a490 | 2960 | maxpages = swapfile_maximum_size; |
d6bbbd29 | 2961 | last_page = swap_header->info.last_page; |
a06ad633 TA |
2962 | if (!last_page) { |
2963 | pr_warn("Empty swap-file\n"); | |
2964 | return 0; | |
2965 | } | |
d6bbbd29 | 2966 | if (last_page > maxpages) { |
465c47fd | 2967 | pr_warn("Truncating oversized swap area, only using %luk out of %luk\n", |
00cde042 | 2968 | K(maxpages), K(last_page)); |
d6bbbd29 RJ |
2969 | } |
2970 | if (maxpages > last_page) { | |
2971 | maxpages = last_page + 1; | |
ca8bd38b CEB |
2972 | /* p->max is an unsigned int: don't overflow it */ |
2973 | if ((unsigned int)maxpages == 0) | |
2974 | maxpages = UINT_MAX; | |
2975 | } | |
2976 | p->highest_bit = maxpages - 1; | |
2977 | ||
2978 | if (!maxpages) | |
38719025 | 2979 | return 0; |
ca8bd38b CEB |
2980 | swapfilepages = i_size_read(inode) >> PAGE_SHIFT; |
2981 | if (swapfilepages && maxpages > swapfilepages) { | |
465c47fd | 2982 | pr_warn("Swap area shorter than signature indicates\n"); |
38719025 | 2983 | return 0; |
ca8bd38b CEB |
2984 | } |
2985 | if (swap_header->info.nr_badpages && S_ISREG(inode->i_mode)) | |
38719025 | 2986 | return 0; |
ca8bd38b | 2987 | if (swap_header->info.nr_badpages > MAX_SWAP_BADPAGES) |
38719025 | 2988 | return 0; |
ca8bd38b CEB |
2989 | |
2990 | return maxpages; | |
ca8bd38b CEB |
2991 | } |
2992 | ||
4b3ef9da | 2993 | #define SWAP_CLUSTER_INFO_COLS \ |
235b6217 | 2994 | DIV_ROUND_UP(L1_CACHE_BYTES, sizeof(struct swap_cluster_info)) |
4b3ef9da HY |
2995 | #define SWAP_CLUSTER_SPACE_COLS \ |
2996 | DIV_ROUND_UP(SWAP_ADDRESS_SPACE_PAGES, SWAPFILE_CLUSTER) | |
2997 | #define SWAP_CLUSTER_COLS \ | |
2998 | max_t(unsigned int, SWAP_CLUSTER_INFO_COLS, SWAP_CLUSTER_SPACE_COLS) | |
235b6217 | 2999 | |
915d4d7b CEB |
3000 | static int setup_swap_map_and_extents(struct swap_info_struct *p, |
3001 | union swap_header *swap_header, | |
3002 | unsigned char *swap_map, | |
2a8f9449 | 3003 | struct swap_cluster_info *cluster_info, |
915d4d7b CEB |
3004 | unsigned long maxpages, |
3005 | sector_t *span) | |
3006 | { | |
235b6217 | 3007 | unsigned int j, k; |
915d4d7b CEB |
3008 | unsigned int nr_good_pages; |
3009 | int nr_extents; | |
2a8f9449 | 3010 | unsigned long nr_clusters = DIV_ROUND_UP(maxpages, SWAPFILE_CLUSTER); |
235b6217 HY |
3011 | unsigned long col = p->cluster_next / SWAPFILE_CLUSTER % SWAP_CLUSTER_COLS; |
3012 | unsigned long i, idx; | |
915d4d7b CEB |
3013 | |
3014 | nr_good_pages = maxpages - 1; /* omit header page */ | |
3015 | ||
6b534915 HY |
3016 | cluster_list_init(&p->free_clusters); |
3017 | cluster_list_init(&p->discard_clusters); | |
2a8f9449 | 3018 | |
915d4d7b CEB |
3019 | for (i = 0; i < swap_header->info.nr_badpages; i++) { |
3020 | unsigned int page_nr = swap_header->info.badpages[i]; | |
bdb8e3f6 CEB |
3021 | if (page_nr == 0 || page_nr > swap_header->info.last_page) |
3022 | return -EINVAL; | |
915d4d7b CEB |
3023 | if (page_nr < maxpages) { |
3024 | swap_map[page_nr] = SWAP_MAP_BAD; | |
3025 | nr_good_pages--; | |
2a8f9449 SL |
3026 | /* |
3027 | * Haven't marked the cluster free yet, no list | |
3028 | * operation involved | |
3029 | */ | |
3030 | inc_cluster_info_page(p, cluster_info, page_nr); | |
915d4d7b CEB |
3031 | } |
3032 | } | |
3033 | ||
2a8f9449 SL |
3034 | /* Haven't marked the cluster free yet, no list operation involved */ |
3035 | for (i = maxpages; i < round_up(maxpages, SWAPFILE_CLUSTER); i++) | |
3036 | inc_cluster_info_page(p, cluster_info, i); | |
3037 | ||
915d4d7b CEB |
3038 | if (nr_good_pages) { |
3039 | swap_map[0] = SWAP_MAP_BAD; | |
2a8f9449 SL |
3040 | /* |
3041 | * Not mark the cluster free yet, no list | |
3042 | * operation involved | |
3043 | */ | |
3044 | inc_cluster_info_page(p, cluster_info, 0); | |
915d4d7b CEB |
3045 | p->max = maxpages; |
3046 | p->pages = nr_good_pages; | |
3047 | nr_extents = setup_swap_extents(p, span); | |
bdb8e3f6 CEB |
3048 | if (nr_extents < 0) |
3049 | return nr_extents; | |
915d4d7b CEB |
3050 | nr_good_pages = p->pages; |
3051 | } | |
3052 | if (!nr_good_pages) { | |
465c47fd | 3053 | pr_warn("Empty swap-file\n"); |
bdb8e3f6 | 3054 | return -EINVAL; |
915d4d7b CEB |
3055 | } |
3056 | ||
2a8f9449 SL |
3057 | if (!cluster_info) |
3058 | return nr_extents; | |
3059 | ||
235b6217 | 3060 | |
4b3ef9da HY |
3061 | /* |
3062 | * Reduce false cache line sharing between cluster_info and | |
3063 | * sharing same address space. | |
3064 | */ | |
235b6217 HY |
3065 | for (k = 0; k < SWAP_CLUSTER_COLS; k++) { |
3066 | j = (k + col) % SWAP_CLUSTER_COLS; | |
3067 | for (i = 0; i < DIV_ROUND_UP(nr_clusters, SWAP_CLUSTER_COLS); i++) { | |
3068 | idx = i * SWAP_CLUSTER_COLS + j; | |
3069 | if (idx >= nr_clusters) | |
3070 | continue; | |
3071 | if (cluster_count(&cluster_info[idx])) | |
3072 | continue; | |
2a8f9449 | 3073 | cluster_set_flag(&cluster_info[idx], CLUSTER_FLAG_FREE); |
6b534915 HY |
3074 | cluster_list_add_tail(&p->free_clusters, cluster_info, |
3075 | idx); | |
2a8f9449 | 3076 | } |
2a8f9449 | 3077 | } |
915d4d7b | 3078 | return nr_extents; |
915d4d7b CEB |
3079 | } |
3080 | ||
53cbb243 CEB |
3081 | SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags) |
3082 | { | |
3083 | struct swap_info_struct *p; | |
91a27b2a | 3084 | struct filename *name; |
53cbb243 CEB |
3085 | struct file *swap_file = NULL; |
3086 | struct address_space *mapping; | |
51cc3a66 | 3087 | struct dentry *dentry; |
40531542 | 3088 | int prio; |
53cbb243 CEB |
3089 | int error; |
3090 | union swap_header *swap_header; | |
915d4d7b | 3091 | int nr_extents; |
53cbb243 CEB |
3092 | sector_t span; |
3093 | unsigned long maxpages; | |
53cbb243 | 3094 | unsigned char *swap_map = NULL; |
2a8f9449 | 3095 | struct swap_cluster_info *cluster_info = NULL; |
53cbb243 CEB |
3096 | struct page *page = NULL; |
3097 | struct inode *inode = NULL; | |
7cbf3192 | 3098 | bool inced_nr_rotate_swap = false; |
53cbb243 | 3099 | |
d15cab97 HD |
3100 | if (swap_flags & ~SWAP_FLAGS_VALID) |
3101 | return -EINVAL; | |
3102 | ||
53cbb243 CEB |
3103 | if (!capable(CAP_SYS_ADMIN)) |
3104 | return -EPERM; | |
3105 | ||
a2468cc9 AL |
3106 | if (!swap_avail_heads) |
3107 | return -ENOMEM; | |
3108 | ||
53cbb243 | 3109 | p = alloc_swap_info(); |
2542e513 CEB |
3110 | if (IS_ERR(p)) |
3111 | return PTR_ERR(p); | |
53cbb243 | 3112 | |
815c2c54 SL |
3113 | INIT_WORK(&p->discard_work, swap_discard_work); |
3114 | ||
1da177e4 | 3115 | name = getname(specialfile); |
1da177e4 | 3116 | if (IS_ERR(name)) { |
7de7fb6b | 3117 | error = PTR_ERR(name); |
1da177e4 | 3118 | name = NULL; |
bd69010b | 3119 | goto bad_swap; |
1da177e4 | 3120 | } |
51d908b3 | 3121 | swap_file = file_open_name(name, O_RDWR | O_LARGEFILE | O_EXCL, 0); |
1da177e4 | 3122 | if (IS_ERR(swap_file)) { |
7de7fb6b | 3123 | error = PTR_ERR(swap_file); |
1da177e4 | 3124 | swap_file = NULL; |
bd69010b | 3125 | goto bad_swap; |
1da177e4 LT |
3126 | } |
3127 | ||
3128 | p->swap_file = swap_file; | |
3129 | mapping = swap_file->f_mapping; | |
51cc3a66 | 3130 | dentry = swap_file->f_path.dentry; |
2130781e | 3131 | inode = mapping->host; |
6f179af8 | 3132 | |
4d0e1e10 CEB |
3133 | error = claim_swapfile(p, inode); |
3134 | if (unlikely(error)) | |
1da177e4 | 3135 | goto bad_swap; |
1da177e4 | 3136 | |
d795a90e | 3137 | inode_lock(inode); |
51cc3a66 HD |
3138 | if (d_unlinked(dentry) || cant_mount(dentry)) { |
3139 | error = -ENOENT; | |
3140 | goto bad_swap_unlock_inode; | |
3141 | } | |
d795a90e NA |
3142 | if (IS_SWAPFILE(inode)) { |
3143 | error = -EBUSY; | |
3144 | goto bad_swap_unlock_inode; | |
3145 | } | |
3146 | ||
1da177e4 LT |
3147 | /* |
3148 | * Read the swap header. | |
3149 | */ | |
7e0a1265 | 3150 | if (!mapping->a_ops->read_folio) { |
1da177e4 | 3151 | error = -EINVAL; |
d795a90e | 3152 | goto bad_swap_unlock_inode; |
1da177e4 | 3153 | } |
090d2b18 | 3154 | page = read_mapping_page(mapping, 0, swap_file); |
1da177e4 LT |
3155 | if (IS_ERR(page)) { |
3156 | error = PTR_ERR(page); | |
d795a90e | 3157 | goto bad_swap_unlock_inode; |
1da177e4 | 3158 | } |
81e33971 | 3159 | swap_header = kmap(page); |
1da177e4 | 3160 | |
ca8bd38b CEB |
3161 | maxpages = read_swap_header(p, swap_header, inode); |
3162 | if (unlikely(!maxpages)) { | |
1da177e4 | 3163 | error = -EINVAL; |
d795a90e | 3164 | goto bad_swap_unlock_inode; |
1da177e4 | 3165 | } |
886bb7e9 | 3166 | |
81e33971 | 3167 | /* OK, set up the swap map and apply the bad block list */ |
803d0c83 | 3168 | swap_map = vzalloc(maxpages); |
81e33971 HD |
3169 | if (!swap_map) { |
3170 | error = -ENOMEM; | |
d795a90e | 3171 | goto bad_swap_unlock_inode; |
81e33971 | 3172 | } |
f0571429 | 3173 | |
36d25489 | 3174 | if (p->bdev && bdev_stable_writes(p->bdev)) |
f0571429 MK |
3175 | p->flags |= SWP_STABLE_WRITES; |
3176 | ||
3222d8c2 | 3177 | if (p->bdev && bdev_synchronous(p->bdev)) |
539a6fea MK |
3178 | p->flags |= SWP_SYNCHRONOUS_IO; |
3179 | ||
10f0d2a5 | 3180 | if (p->bdev && bdev_nonrot(p->bdev)) { |
845982eb | 3181 | int cpu, i; |
235b6217 | 3182 | unsigned long ci, nr_cluster; |
6f179af8 | 3183 | |
2a8f9449 | 3184 | p->flags |= SWP_SOLIDSTATE; |
49070588 HY |
3185 | p->cluster_next_cpu = alloc_percpu(unsigned int); |
3186 | if (!p->cluster_next_cpu) { | |
3187 | error = -ENOMEM; | |
3188 | goto bad_swap_unlock_inode; | |
3189 | } | |
2a8f9449 SL |
3190 | /* |
3191 | * select a random position to start with to help wear leveling | |
3192 | * SSD | |
3193 | */ | |
49070588 HY |
3194 | for_each_possible_cpu(cpu) { |
3195 | per_cpu(*p->cluster_next_cpu, cpu) = | |
e8a533cb | 3196 | get_random_u32_inclusive(1, p->highest_bit); |
49070588 | 3197 | } |
235b6217 | 3198 | nr_cluster = DIV_ROUND_UP(maxpages, SWAPFILE_CLUSTER); |
2a8f9449 | 3199 | |
778e1cdd | 3200 | cluster_info = kvcalloc(nr_cluster, sizeof(*cluster_info), |
54f180d3 | 3201 | GFP_KERNEL); |
2a8f9449 SL |
3202 | if (!cluster_info) { |
3203 | error = -ENOMEM; | |
d795a90e | 3204 | goto bad_swap_unlock_inode; |
2a8f9449 | 3205 | } |
235b6217 HY |
3206 | |
3207 | for (ci = 0; ci < nr_cluster; ci++) | |
3208 | spin_lock_init(&((cluster_info + ci)->lock)); | |
3209 | ||
ebc2a1a6 SL |
3210 | p->percpu_cluster = alloc_percpu(struct percpu_cluster); |
3211 | if (!p->percpu_cluster) { | |
3212 | error = -ENOMEM; | |
d795a90e | 3213 | goto bad_swap_unlock_inode; |
ebc2a1a6 | 3214 | } |
6f179af8 | 3215 | for_each_possible_cpu(cpu) { |
ebc2a1a6 | 3216 | struct percpu_cluster *cluster; |
14c62da2 | 3217 | |
6f179af8 | 3218 | cluster = per_cpu_ptr(p->percpu_cluster, cpu); |
845982eb RR |
3219 | for (i = 0; i < SWAP_NR_ORDERS; i++) |
3220 | cluster->next[i] = SWAP_NEXT_INVALID; | |
ebc2a1a6 | 3221 | } |
7cbf3192 | 3222 | } else { |
81a0298b | 3223 | atomic_inc(&nr_rotate_swap); |
7cbf3192 OS |
3224 | inced_nr_rotate_swap = true; |
3225 | } | |
1da177e4 | 3226 | |
1421ef3c CEB |
3227 | error = swap_cgroup_swapon(p->type, maxpages); |
3228 | if (error) | |
d795a90e | 3229 | goto bad_swap_unlock_inode; |
1421ef3c | 3230 | |
915d4d7b | 3231 | nr_extents = setup_swap_map_and_extents(p, swap_header, swap_map, |
2a8f9449 | 3232 | cluster_info, maxpages, &span); |
915d4d7b CEB |
3233 | if (unlikely(nr_extents < 0)) { |
3234 | error = nr_extents; | |
d795a90e | 3235 | goto bad_swap_unlock_inode; |
1da177e4 | 3236 | } |
1da177e4 | 3237 | |
70200574 CH |
3238 | if ((swap_flags & SWAP_FLAG_DISCARD) && |
3239 | p->bdev && bdev_max_discard_sectors(p->bdev)) { | |
2a8f9449 SL |
3240 | /* |
3241 | * When discard is enabled for swap with no particular | |
3242 | * policy flagged, we set all swap discard flags here in | |
3243 | * order to sustain backward compatibility with older | |
3244 | * swapon(8) releases. | |
3245 | */ | |
3246 | p->flags |= (SWP_DISCARDABLE | SWP_AREA_DISCARD | | |
3247 | SWP_PAGE_DISCARD); | |
dcf6b7dd | 3248 | |
2a8f9449 SL |
3249 | /* |
3250 | * By flagging sys_swapon, a sysadmin can tell us to | |
3251 | * either do single-time area discards only, or to just | |
3252 | * perform discards for released swap page-clusters. | |
3253 | * Now it's time to adjust the p->flags accordingly. | |
3254 | */ | |
3255 | if (swap_flags & SWAP_FLAG_DISCARD_ONCE) | |
3256 | p->flags &= ~SWP_PAGE_DISCARD; | |
3257 | else if (swap_flags & SWAP_FLAG_DISCARD_PAGES) | |
3258 | p->flags &= ~SWP_AREA_DISCARD; | |
3259 | ||
3260 | /* issue a swapon-time discard if it's still required */ | |
3261 | if (p->flags & SWP_AREA_DISCARD) { | |
3262 | int err = discard_swap(p); | |
3263 | if (unlikely(err)) | |
3264 | pr_err("swapon: discard_swap(%p): %d\n", | |
3265 | p, err); | |
dcf6b7dd | 3266 | } |
20137a49 | 3267 | } |
6a6ba831 | 3268 | |
4b3ef9da HY |
3269 | error = init_swap_address_space(p->type, maxpages); |
3270 | if (error) | |
d795a90e | 3271 | goto bad_swap_unlock_inode; |
4b3ef9da | 3272 | |
44c7c734 | 3273 | error = zswap_swapon(p->type, maxpages); |
bb29fd77 CZ |
3274 | if (error) |
3275 | goto free_swap_address_space; | |
3276 | ||
dc617f29 DW |
3277 | /* |
3278 | * Flush any pending IO and dirty mappings before we start using this | |
3279 | * swap device. | |
3280 | */ | |
3281 | inode->i_flags |= S_SWAPFILE; | |
3282 | error = inode_drain_writes(inode); | |
3283 | if (error) { | |
3284 | inode->i_flags &= ~S_SWAPFILE; | |
bb29fd77 | 3285 | goto free_swap_zswap; |
dc617f29 DW |
3286 | } |
3287 | ||
fc0abb14 | 3288 | mutex_lock(&swapon_mutex); |
40531542 | 3289 | prio = -1; |
78ecba08 | 3290 | if (swap_flags & SWAP_FLAG_PREFER) |
40531542 | 3291 | prio = |
78ecba08 | 3292 | (swap_flags & SWAP_FLAG_PRIO_MASK) >> SWAP_FLAG_PRIO_SHIFT; |
42c06a0e | 3293 | enable_swap_info(p, prio, swap_map, cluster_info); |
c69dbfb8 | 3294 | |
42c06a0e | 3295 | pr_info("Adding %uk swap on %s. Priority:%d extents:%d across:%lluk %s%s%s%s\n", |
00cde042 Z |
3296 | K(p->pages), name->name, p->prio, nr_extents, |
3297 | K((unsigned long long)span), | |
c69dbfb8 | 3298 | (p->flags & SWP_SOLIDSTATE) ? "SS" : "", |
38b5faf4 | 3299 | (p->flags & SWP_DISCARDABLE) ? "D" : "", |
dcf6b7dd | 3300 | (p->flags & SWP_AREA_DISCARD) ? "s" : "", |
42c06a0e | 3301 | (p->flags & SWP_PAGE_DISCARD) ? "c" : ""); |
c69dbfb8 | 3302 | |
fc0abb14 | 3303 | mutex_unlock(&swapon_mutex); |
66d7dd51 KS |
3304 | atomic_inc(&proc_poll_event); |
3305 | wake_up_interruptible(&proc_poll_wait); | |
3306 | ||
1da177e4 LT |
3307 | error = 0; |
3308 | goto out; | |
bb29fd77 CZ |
3309 | free_swap_zswap: |
3310 | zswap_swapoff(p->type); | |
822bca52 ML |
3311 | free_swap_address_space: |
3312 | exit_swap_address_space(p->type); | |
d795a90e NA |
3313 | bad_swap_unlock_inode: |
3314 | inode_unlock(inode); | |
1da177e4 | 3315 | bad_swap: |
ebc2a1a6 SL |
3316 | free_percpu(p->percpu_cluster); |
3317 | p->percpu_cluster = NULL; | |
49070588 HY |
3318 | free_percpu(p->cluster_next_cpu); |
3319 | p->cluster_next_cpu = NULL; | |
d795a90e | 3320 | inode = NULL; |
4cd3bb10 | 3321 | destroy_swap_extents(p); |
e8e6c2ec | 3322 | swap_cgroup_swapoff(p->type); |
5d337b91 | 3323 | spin_lock(&swap_lock); |
1da177e4 | 3324 | p->swap_file = NULL; |
1da177e4 | 3325 | p->flags = 0; |
5d337b91 | 3326 | spin_unlock(&swap_lock); |
1da177e4 | 3327 | vfree(swap_map); |
8606a1a9 | 3328 | kvfree(cluster_info); |
7cbf3192 OS |
3329 | if (inced_nr_rotate_swap) |
3330 | atomic_dec(&nr_rotate_swap); | |
d795a90e | 3331 | if (swap_file) |
1da177e4 LT |
3332 | filp_close(swap_file, NULL); |
3333 | out: | |
3334 | if (page && !IS_ERR(page)) { | |
3335 | kunmap(page); | |
09cbfeaf | 3336 | put_page(page); |
1da177e4 LT |
3337 | } |
3338 | if (name) | |
3339 | putname(name); | |
1638045c | 3340 | if (inode) |
5955102c | 3341 | inode_unlock(inode); |
039939a6 TC |
3342 | if (!error) |
3343 | enable_swap_slots_cache(); | |
1da177e4 LT |
3344 | return error; |
3345 | } | |
3346 | ||
3347 | void si_swapinfo(struct sysinfo *val) | |
3348 | { | |
efa90a98 | 3349 | unsigned int type; |
1da177e4 LT |
3350 | unsigned long nr_to_be_unused = 0; |
3351 | ||
5d337b91 | 3352 | spin_lock(&swap_lock); |
efa90a98 HD |
3353 | for (type = 0; type < nr_swapfiles; type++) { |
3354 | struct swap_info_struct *si = swap_info[type]; | |
3355 | ||
3356 | if ((si->flags & SWP_USED) && !(si->flags & SWP_WRITEOK)) | |
c8945306 | 3357 | nr_to_be_unused += READ_ONCE(si->inuse_pages); |
1da177e4 | 3358 | } |
ec8acf20 | 3359 | val->freeswap = atomic_long_read(&nr_swap_pages) + nr_to_be_unused; |
1da177e4 | 3360 | val->totalswap = total_swap_pages + nr_to_be_unused; |
5d337b91 | 3361 | spin_unlock(&swap_lock); |
1da177e4 LT |
3362 | } |
3363 | ||
3364 | /* | |
3365 | * Verify that a swap entry is valid and increment its swap map count. | |
3366 | * | |
355cfa73 KH |
3367 | * Returns error code in following case. |
3368 | * - success -> 0 | |
3369 | * - swp_entry is invalid -> EINVAL | |
3370 | * - swp_entry is migration entry -> EINVAL | |
3371 | * - swap-cache reference is requested but there is already one. -> EEXIST | |
3372 | * - swap-cache reference is requested but the entry is not used. -> ENOENT | |
570a335b | 3373 | * - swap-mapped reference requested but needs continued swap count. -> ENOMEM |
1da177e4 | 3374 | */ |
8d69aaee | 3375 | static int __swap_duplicate(swp_entry_t entry, unsigned char usage) |
1da177e4 | 3376 | { |
73c34b6a | 3377 | struct swap_info_struct *p; |
235b6217 | 3378 | struct swap_cluster_info *ci; |
c10d38cc | 3379 | unsigned long offset; |
8d69aaee HD |
3380 | unsigned char count; |
3381 | unsigned char has_cache; | |
9d9a0334 | 3382 | int err; |
1da177e4 | 3383 | |
c07aee4f | 3384 | p = swp_swap_info(entry); |
235b6217 | 3385 | |
eb085574 | 3386 | offset = swp_offset(entry); |
235b6217 | 3387 | ci = lock_cluster_or_swap_info(p, offset); |
355cfa73 | 3388 | |
253d553b | 3389 | count = p->swap_map[offset]; |
edfe23da SL |
3390 | |
3391 | /* | |
3392 | * swapin_readahead() doesn't check if a swap entry is valid, so the | |
3393 | * swap entry could be SWAP_MAP_BAD. Check here with lock held. | |
3394 | */ | |
3395 | if (unlikely(swap_count(count) == SWAP_MAP_BAD)) { | |
3396 | err = -ENOENT; | |
3397 | goto unlock_out; | |
3398 | } | |
3399 | ||
253d553b HD |
3400 | has_cache = count & SWAP_HAS_CACHE; |
3401 | count &= ~SWAP_HAS_CACHE; | |
3402 | err = 0; | |
355cfa73 | 3403 | |
253d553b | 3404 | if (usage == SWAP_HAS_CACHE) { |
355cfa73 KH |
3405 | |
3406 | /* set SWAP_HAS_CACHE if there is no cache and entry is used */ | |
253d553b HD |
3407 | if (!has_cache && count) |
3408 | has_cache = SWAP_HAS_CACHE; | |
3409 | else if (has_cache) /* someone else added cache */ | |
3410 | err = -EEXIST; | |
3411 | else /* no users remaining */ | |
3412 | err = -ENOENT; | |
355cfa73 KH |
3413 | |
3414 | } else if (count || has_cache) { | |
253d553b | 3415 | |
570a335b HD |
3416 | if ((count & ~COUNT_CONTINUED) < SWAP_MAP_MAX) |
3417 | count += usage; | |
3418 | else if ((count & ~COUNT_CONTINUED) > SWAP_MAP_MAX) | |
253d553b | 3419 | err = -EINVAL; |
570a335b HD |
3420 | else if (swap_count_continued(p, offset, count)) |
3421 | count = COUNT_CONTINUED; | |
3422 | else | |
3423 | err = -ENOMEM; | |
355cfa73 | 3424 | } else |
253d553b HD |
3425 | err = -ENOENT; /* unused swap entry */ |
3426 | ||
e26f0b93 BS |
3427 | if (!err) |
3428 | WRITE_ONCE(p->swap_map[offset], count | has_cache); | |
253d553b | 3429 | |
355cfa73 | 3430 | unlock_out: |
235b6217 | 3431 | unlock_cluster_or_swap_info(p, ci); |
253d553b | 3432 | return err; |
1da177e4 | 3433 | } |
253d553b | 3434 | |
aaa46865 HD |
3435 | /* |
3436 | * Help swapoff by noting that swap entry belongs to shmem/tmpfs | |
3437 | * (in which case its reference count is never incremented). | |
3438 | */ | |
3439 | void swap_shmem_alloc(swp_entry_t entry) | |
3440 | { | |
3441 | __swap_duplicate(entry, SWAP_MAP_SHMEM); | |
3442 | } | |
3443 | ||
355cfa73 | 3444 | /* |
08259d58 HD |
3445 | * Increase reference count of swap entry by 1. |
3446 | * Returns 0 for success, or -ENOMEM if a swap_count_continuation is required | |
3447 | * but could not be atomically allocated. Returns 0, just as if it succeeded, | |
3448 | * if __swap_duplicate() fails for another reason (-EINVAL or -ENOENT), which | |
3449 | * might occur if a page table entry has got corrupted. | |
355cfa73 | 3450 | */ |
570a335b | 3451 | int swap_duplicate(swp_entry_t entry) |
355cfa73 | 3452 | { |
570a335b HD |
3453 | int err = 0; |
3454 | ||
3455 | while (!err && __swap_duplicate(entry, 1) == -ENOMEM) | |
3456 | err = add_swap_count_continuation(entry, GFP_ATOMIC); | |
3457 | return err; | |
355cfa73 | 3458 | } |
1da177e4 | 3459 | |
cb4b86ba | 3460 | /* |
355cfa73 KH |
3461 | * @entry: swap entry for which we allocate swap cache. |
3462 | * | |
73c34b6a | 3463 | * Called when allocating swap cache for existing swap entry, |
355cfa73 | 3464 | * This can return error codes. Returns 0 at success. |
3eeba135 | 3465 | * -EEXIST means there is a swap cache. |
355cfa73 | 3466 | * Note: return code is different from swap_duplicate(). |
cb4b86ba KH |
3467 | */ |
3468 | int swapcache_prepare(swp_entry_t entry) | |
3469 | { | |
253d553b | 3470 | return __swap_duplicate(entry, SWAP_HAS_CACHE); |
cb4b86ba KH |
3471 | } |
3472 | ||
13ddaf26 KS |
3473 | void swapcache_clear(struct swap_info_struct *si, swp_entry_t entry) |
3474 | { | |
3475 | struct swap_cluster_info *ci; | |
3476 | unsigned long offset = swp_offset(entry); | |
3477 | unsigned char usage; | |
3478 | ||
3479 | ci = lock_cluster_or_swap_info(si, offset); | |
3480 | usage = __swap_entry_free_locked(si, offset, SWAP_HAS_CACHE); | |
3481 | unlock_cluster_or_swap_info(si, ci); | |
3482 | if (!usage) | |
3483 | free_swap_slot(entry); | |
3484 | } | |
3485 | ||
0bcac06f MK |
3486 | struct swap_info_struct *swp_swap_info(swp_entry_t entry) |
3487 | { | |
c10d38cc | 3488 | return swap_type_to_swap_info(swp_type(entry)); |
0bcac06f MK |
3489 | } |
3490 | ||
f981c595 | 3491 | /* |
2f52578f | 3492 | * out-of-line methods to avoid include hell. |
f981c595 | 3493 | */ |
2f52578f | 3494 | struct address_space *swapcache_mapping(struct folio *folio) |
f981c595 | 3495 | { |
69fe7d67 | 3496 | return swp_swap_info(folio->swap)->swap_file->f_mapping; |
f981c595 | 3497 | } |
2f52578f | 3498 | EXPORT_SYMBOL_GPL(swapcache_mapping); |
f981c595 | 3499 | |
05b0c7ed | 3500 | pgoff_t __folio_swap_cache_index(struct folio *folio) |
f981c595 | 3501 | { |
7aad25b4 | 3502 | return swap_cache_index(folio->swap); |
f981c595 | 3503 | } |
05b0c7ed | 3504 | EXPORT_SYMBOL_GPL(__folio_swap_cache_index); |
f981c595 | 3505 | |
570a335b HD |
3506 | /* |
3507 | * add_swap_count_continuation - called when a swap count is duplicated | |
3508 | * beyond SWAP_MAP_MAX, it allocates a new page and links that to the entry's | |
3509 | * page of the original vmalloc'ed swap_map, to hold the continuation count | |
3510 | * (for that entry and for its neighbouring PAGE_SIZE swap entries). Called | |
3511 | * again when count is duplicated beyond SWAP_MAP_MAX * SWAP_CONT_MAX, etc. | |
3512 | * | |
3513 | * These continuation pages are seldom referenced: the common paths all work | |
3514 | * on the original swap_map, only referring to a continuation page when the | |
3515 | * low "digit" of a count is incremented or decremented through SWAP_MAP_MAX. | |
3516 | * | |
3517 | * add_swap_count_continuation(, GFP_ATOMIC) can be called while holding | |
3518 | * page table locks; if it fails, add_swap_count_continuation(, GFP_KERNEL) | |
3519 | * can be called after dropping locks. | |
3520 | */ | |
3521 | int add_swap_count_continuation(swp_entry_t entry, gfp_t gfp_mask) | |
3522 | { | |
3523 | struct swap_info_struct *si; | |
235b6217 | 3524 | struct swap_cluster_info *ci; |
570a335b HD |
3525 | struct page *head; |
3526 | struct page *page; | |
3527 | struct page *list_page; | |
3528 | pgoff_t offset; | |
3529 | unsigned char count; | |
eb085574 | 3530 | int ret = 0; |
570a335b HD |
3531 | |
3532 | /* | |
3533 | * When debugging, it's easier to use __GFP_ZERO here; but it's better | |
3534 | * for latency not to zero a page while GFP_ATOMIC and holding locks. | |
3535 | */ | |
3536 | page = alloc_page(gfp_mask | __GFP_HIGHMEM); | |
3537 | ||
eb085574 | 3538 | si = get_swap_device(entry); |
570a335b HD |
3539 | if (!si) { |
3540 | /* | |
3541 | * An acceptable race has occurred since the failing | |
eb085574 | 3542 | * __swap_duplicate(): the swap device may be swapoff |
570a335b HD |
3543 | */ |
3544 | goto outer; | |
3545 | } | |
eb085574 | 3546 | spin_lock(&si->lock); |
570a335b HD |
3547 | |
3548 | offset = swp_offset(entry); | |
235b6217 HY |
3549 | |
3550 | ci = lock_cluster(si, offset); | |
3551 | ||
d8aa24e0 | 3552 | count = swap_count(si->swap_map[offset]); |
570a335b HD |
3553 | |
3554 | if ((count & ~COUNT_CONTINUED) != SWAP_MAP_MAX) { | |
3555 | /* | |
3556 | * The higher the swap count, the more likely it is that tasks | |
3557 | * will race to add swap count continuation: we need to avoid | |
3558 | * over-provisioning. | |
3559 | */ | |
3560 | goto out; | |
3561 | } | |
3562 | ||
3563 | if (!page) { | |
eb085574 HY |
3564 | ret = -ENOMEM; |
3565 | goto out; | |
570a335b HD |
3566 | } |
3567 | ||
570a335b HD |
3568 | head = vmalloc_to_page(si->swap_map + offset); |
3569 | offset &= ~PAGE_MASK; | |
3570 | ||
2628bd6f | 3571 | spin_lock(&si->cont_lock); |
570a335b HD |
3572 | /* |
3573 | * Page allocation does not initialize the page's lru field, | |
3574 | * but it does always reset its private field. | |
3575 | */ | |
3576 | if (!page_private(head)) { | |
3577 | BUG_ON(count & COUNT_CONTINUED); | |
3578 | INIT_LIST_HEAD(&head->lru); | |
3579 | set_page_private(head, SWP_CONTINUED); | |
3580 | si->flags |= SWP_CONTINUED; | |
3581 | } | |
3582 | ||
3583 | list_for_each_entry(list_page, &head->lru, lru) { | |
3584 | unsigned char *map; | |
3585 | ||
3586 | /* | |
3587 | * If the previous map said no continuation, but we've found | |
3588 | * a continuation page, free our allocation and use this one. | |
3589 | */ | |
3590 | if (!(count & COUNT_CONTINUED)) | |
2628bd6f | 3591 | goto out_unlock_cont; |
570a335b | 3592 | |
829c3151 | 3593 | map = kmap_local_page(list_page) + offset; |
570a335b | 3594 | count = *map; |
829c3151 | 3595 | kunmap_local(map); |
570a335b HD |
3596 | |
3597 | /* | |
3598 | * If this continuation count now has some space in it, | |
3599 | * free our allocation and use this one. | |
3600 | */ | |
3601 | if ((count & ~COUNT_CONTINUED) != SWAP_CONT_MAX) | |
2628bd6f | 3602 | goto out_unlock_cont; |
570a335b HD |
3603 | } |
3604 | ||
3605 | list_add_tail(&page->lru, &head->lru); | |
3606 | page = NULL; /* now it's attached, don't free it */ | |
2628bd6f HY |
3607 | out_unlock_cont: |
3608 | spin_unlock(&si->cont_lock); | |
570a335b | 3609 | out: |
235b6217 | 3610 | unlock_cluster(ci); |
ec8acf20 | 3611 | spin_unlock(&si->lock); |
eb085574 | 3612 | put_swap_device(si); |
570a335b HD |
3613 | outer: |
3614 | if (page) | |
3615 | __free_page(page); | |
eb085574 | 3616 | return ret; |
570a335b HD |
3617 | } |
3618 | ||
3619 | /* | |
3620 | * swap_count_continued - when the original swap_map count is incremented | |
3621 | * from SWAP_MAP_MAX, check if there is already a continuation page to carry | |
3622 | * into, carry if so, or else fail until a new continuation page is allocated; | |
3623 | * when the original swap_map count is decremented from 0 with continuation, | |
3624 | * borrow from the continuation and report whether it still holds more. | |
235b6217 HY |
3625 | * Called while __swap_duplicate() or swap_entry_free() holds swap or cluster |
3626 | * lock. | |
570a335b HD |
3627 | */ |
3628 | static bool swap_count_continued(struct swap_info_struct *si, | |
3629 | pgoff_t offset, unsigned char count) | |
3630 | { | |
3631 | struct page *head; | |
3632 | struct page *page; | |
3633 | unsigned char *map; | |
2628bd6f | 3634 | bool ret; |
570a335b HD |
3635 | |
3636 | head = vmalloc_to_page(si->swap_map + offset); | |
3637 | if (page_private(head) != SWP_CONTINUED) { | |
3638 | BUG_ON(count & COUNT_CONTINUED); | |
3639 | return false; /* need to add count continuation */ | |
3640 | } | |
3641 | ||
2628bd6f | 3642 | spin_lock(&si->cont_lock); |
570a335b | 3643 | offset &= ~PAGE_MASK; |
213516ac | 3644 | page = list_next_entry(head, lru); |
829c3151 | 3645 | map = kmap_local_page(page) + offset; |
570a335b HD |
3646 | |
3647 | if (count == SWAP_MAP_MAX) /* initial increment from swap_map */ | |
3648 | goto init_map; /* jump over SWAP_CONT_MAX checks */ | |
3649 | ||
3650 | if (count == (SWAP_MAP_MAX | COUNT_CONTINUED)) { /* incrementing */ | |
3651 | /* | |
3652 | * Think of how you add 1 to 999 | |
3653 | */ | |
3654 | while (*map == (SWAP_CONT_MAX | COUNT_CONTINUED)) { | |
829c3151 | 3655 | kunmap_local(map); |
213516ac | 3656 | page = list_next_entry(page, lru); |
570a335b | 3657 | BUG_ON(page == head); |
829c3151 | 3658 | map = kmap_local_page(page) + offset; |
570a335b HD |
3659 | } |
3660 | if (*map == SWAP_CONT_MAX) { | |
829c3151 | 3661 | kunmap_local(map); |
213516ac | 3662 | page = list_next_entry(page, lru); |
2628bd6f HY |
3663 | if (page == head) { |
3664 | ret = false; /* add count continuation */ | |
3665 | goto out; | |
3666 | } | |
829c3151 | 3667 | map = kmap_local_page(page) + offset; |
570a335b HD |
3668 | init_map: *map = 0; /* we didn't zero the page */ |
3669 | } | |
3670 | *map += 1; | |
829c3151 | 3671 | kunmap_local(map); |
213516ac | 3672 | while ((page = list_prev_entry(page, lru)) != head) { |
829c3151 | 3673 | map = kmap_local_page(page) + offset; |
570a335b | 3674 | *map = COUNT_CONTINUED; |
829c3151 | 3675 | kunmap_local(map); |
570a335b | 3676 | } |
2628bd6f | 3677 | ret = true; /* incremented */ |
570a335b HD |
3678 | |
3679 | } else { /* decrementing */ | |
3680 | /* | |
3681 | * Think of how you subtract 1 from 1000 | |
3682 | */ | |
3683 | BUG_ON(count != COUNT_CONTINUED); | |
3684 | while (*map == COUNT_CONTINUED) { | |
829c3151 | 3685 | kunmap_local(map); |
213516ac | 3686 | page = list_next_entry(page, lru); |
570a335b | 3687 | BUG_ON(page == head); |
829c3151 | 3688 | map = kmap_local_page(page) + offset; |
570a335b HD |
3689 | } |
3690 | BUG_ON(*map == 0); | |
3691 | *map -= 1; | |
3692 | if (*map == 0) | |
3693 | count = 0; | |
829c3151 | 3694 | kunmap_local(map); |
213516ac | 3695 | while ((page = list_prev_entry(page, lru)) != head) { |
829c3151 | 3696 | map = kmap_local_page(page) + offset; |
570a335b HD |
3697 | *map = SWAP_CONT_MAX | count; |
3698 | count = COUNT_CONTINUED; | |
829c3151 | 3699 | kunmap_local(map); |
570a335b | 3700 | } |
2628bd6f | 3701 | ret = count == COUNT_CONTINUED; |
570a335b | 3702 | } |
2628bd6f HY |
3703 | out: |
3704 | spin_unlock(&si->cont_lock); | |
3705 | return ret; | |
570a335b HD |
3706 | } |
3707 | ||
3708 | /* | |
3709 | * free_swap_count_continuations - swapoff free all the continuation pages | |
3710 | * appended to the swap_map, after swap_map is quiesced, before vfree'ing it. | |
3711 | */ | |
3712 | static void free_swap_count_continuations(struct swap_info_struct *si) | |
3713 | { | |
3714 | pgoff_t offset; | |
3715 | ||
3716 | for (offset = 0; offset < si->max; offset += PAGE_SIZE) { | |
3717 | struct page *head; | |
3718 | head = vmalloc_to_page(si->swap_map + offset); | |
3719 | if (page_private(head)) { | |
0d576d20 GT |
3720 | struct page *page, *next; |
3721 | ||
3722 | list_for_each_entry_safe(page, next, &head->lru, lru) { | |
3723 | list_del(&page->lru); | |
570a335b HD |
3724 | __free_page(page); |
3725 | } | |
3726 | } | |
3727 | } | |
3728 | } | |
a2468cc9 | 3729 | |
2cf85583 | 3730 | #if defined(CONFIG_MEMCG) && defined(CONFIG_BLK_CGROUP) |
3e4fb13a | 3731 | void __folio_throttle_swaprate(struct folio *folio, gfp_t gfp) |
2cf85583 TH |
3732 | { |
3733 | struct swap_info_struct *si, *next; | |
3e4fb13a | 3734 | int nid = folio_nid(folio); |
6caa6a07 | 3735 | |
3e4fb13a | 3736 | if (!(gfp & __GFP_IO)) |
2cf85583 TH |
3737 | return; |
3738 | ||
80e75021 KW |
3739 | if (!__has_usable_swap()) |
3740 | return; | |
3741 | ||
2cf85583 TH |
3742 | if (!blk_cgroup_congested()) |
3743 | return; | |
3744 | ||
3745 | /* | |
3746 | * We've already scheduled a throttle, avoid taking the global swap | |
3747 | * lock. | |
3748 | */ | |
f05837ed | 3749 | if (current->throttle_disk) |
2cf85583 TH |
3750 | return; |
3751 | ||
3752 | spin_lock(&swap_avail_lock); | |
6caa6a07 JW |
3753 | plist_for_each_entry_safe(si, next, &swap_avail_heads[nid], |
3754 | avail_lists[nid]) { | |
2cf85583 | 3755 | if (si->bdev) { |
de185b56 | 3756 | blkcg_schedule_throttle(si->bdev->bd_disk, true); |
2cf85583 TH |
3757 | break; |
3758 | } | |
3759 | } | |
3760 | spin_unlock(&swap_avail_lock); | |
3761 | } | |
3762 | #endif | |
3763 | ||
a2468cc9 AL |
3764 | static int __init swapfile_init(void) |
3765 | { | |
3766 | int nid; | |
3767 | ||
3768 | swap_avail_heads = kmalloc_array(nr_node_ids, sizeof(struct plist_head), | |
3769 | GFP_KERNEL); | |
3770 | if (!swap_avail_heads) { | |
3771 | pr_emerg("Not enough memory for swap heads, swap is disabled\n"); | |
3772 | return -ENOMEM; | |
3773 | } | |
3774 | ||
3775 | for_each_node(nid) | |
3776 | plist_head_init(&swap_avail_heads[nid]); | |
3777 | ||
be45a490 PX |
3778 | swapfile_maximum_size = arch_max_swapfile_size(); |
3779 | ||
5154e607 PX |
3780 | #ifdef CONFIG_MIGRATION |
3781 | if (swapfile_maximum_size >= (1UL << SWP_MIG_TOTAL_BITS)) | |
3782 | swap_migration_ad_supported = true; | |
3783 | #endif /* CONFIG_MIGRATION */ | |
3784 | ||
a2468cc9 AL |
3785 | return 0; |
3786 | } | |
3787 | subsys_initcall(swapfile_init); |