Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * linux/mm/swapfile.c | |
3 | * | |
4 | * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds | |
5 | * Swap reorganised 29.12.95, Stephen Tweedie | |
6 | */ | |
7 | ||
1da177e4 LT |
8 | #include <linux/mm.h> |
9 | #include <linux/hugetlb.h> | |
10 | #include <linux/mman.h> | |
11 | #include <linux/slab.h> | |
12 | #include <linux/kernel_stat.h> | |
13 | #include <linux/swap.h> | |
14 | #include <linux/vmalloc.h> | |
15 | #include <linux/pagemap.h> | |
16 | #include <linux/namei.h> | |
17 | #include <linux/shm.h> | |
18 | #include <linux/blkdev.h> | |
19 | #include <linux/writeback.h> | |
20 | #include <linux/proc_fs.h> | |
21 | #include <linux/seq_file.h> | |
22 | #include <linux/init.h> | |
23 | #include <linux/module.h> | |
24 | #include <linux/rmap.h> | |
25 | #include <linux/security.h> | |
26 | #include <linux/backing-dev.h> | |
fc0abb14 | 27 | #include <linux/mutex.h> |
c59ede7b | 28 | #include <linux/capability.h> |
1da177e4 LT |
29 | #include <linux/syscalls.h> |
30 | ||
31 | #include <asm/pgtable.h> | |
32 | #include <asm/tlbflush.h> | |
33 | #include <linux/swapops.h> | |
34 | ||
5d337b91 | 35 | DEFINE_SPINLOCK(swap_lock); |
1da177e4 LT |
36 | unsigned int nr_swapfiles; |
37 | long total_swap_pages; | |
38 | static int swap_overflow; | |
39 | ||
1da177e4 LT |
40 | static const char Bad_file[] = "Bad swap file entry "; |
41 | static const char Unused_file[] = "Unused swap file entry "; | |
42 | static const char Bad_offset[] = "Bad swap offset entry "; | |
43 | static const char Unused_offset[] = "Unused swap offset entry "; | |
44 | ||
45 | struct swap_list_t swap_list = {-1, -1}; | |
46 | ||
f577eb30 | 47 | static struct swap_info_struct swap_info[MAX_SWAPFILES]; |
1da177e4 | 48 | |
fc0abb14 | 49 | static DEFINE_MUTEX(swapon_mutex); |
1da177e4 LT |
50 | |
51 | /* | |
52 | * We need this because the bdev->unplug_fn can sleep and we cannot | |
5d337b91 | 53 | * hold swap_lock while calling the unplug_fn. And swap_lock |
fc0abb14 | 54 | * cannot be turned into a mutex. |
1da177e4 LT |
55 | */ |
56 | static DECLARE_RWSEM(swap_unplug_sem); | |
57 | ||
1da177e4 LT |
58 | void swap_unplug_io_fn(struct backing_dev_info *unused_bdi, struct page *page) |
59 | { | |
60 | swp_entry_t entry; | |
61 | ||
62 | down_read(&swap_unplug_sem); | |
4c21e2f2 | 63 | entry.val = page_private(page); |
1da177e4 LT |
64 | if (PageSwapCache(page)) { |
65 | struct block_device *bdev = swap_info[swp_type(entry)].bdev; | |
66 | struct backing_dev_info *bdi; | |
67 | ||
68 | /* | |
69 | * If the page is removed from swapcache from under us (with a | |
70 | * racy try_to_unuse/swapoff) we need an additional reference | |
4c21e2f2 HD |
71 | * count to avoid reading garbage from page_private(page) above. |
72 | * If the WARN_ON triggers during a swapoff it maybe the race | |
1da177e4 LT |
73 | * condition and it's harmless. However if it triggers without |
74 | * swapoff it signals a problem. | |
75 | */ | |
76 | WARN_ON(page_count(page) <= 1); | |
77 | ||
78 | bdi = bdev->bd_inode->i_mapping->backing_dev_info; | |
ba32311e | 79 | blk_run_backing_dev(bdi, page); |
1da177e4 LT |
80 | } |
81 | up_read(&swap_unplug_sem); | |
82 | } | |
83 | ||
048c27fd HD |
84 | #define SWAPFILE_CLUSTER 256 |
85 | #define LATENCY_LIMIT 256 | |
86 | ||
6eb396dc | 87 | static inline unsigned long scan_swap_map(struct swap_info_struct *si) |
1da177e4 | 88 | { |
7dfad418 | 89 | unsigned long offset, last_in_cluster; |
048c27fd | 90 | int latency_ration = LATENCY_LIMIT; |
7dfad418 | 91 | |
1da177e4 | 92 | /* |
7dfad418 HD |
93 | * We try to cluster swap pages by allocating them sequentially |
94 | * in swap. Once we've allocated SWAPFILE_CLUSTER pages this | |
95 | * way, however, we resort to first-free allocation, starting | |
96 | * a new cluster. This prevents us from scattering swap pages | |
97 | * all over the entire swap partition, so that we reduce | |
98 | * overall disk seek times between swap pages. -- sct | |
99 | * But we do now try to find an empty cluster. -Andrea | |
100 | */ | |
101 | ||
52b7efdb | 102 | si->flags += SWP_SCANNING; |
7dfad418 HD |
103 | if (unlikely(!si->cluster_nr)) { |
104 | si->cluster_nr = SWAPFILE_CLUSTER - 1; | |
105 | if (si->pages - si->inuse_pages < SWAPFILE_CLUSTER) | |
106 | goto lowest; | |
5d337b91 | 107 | spin_unlock(&swap_lock); |
7dfad418 HD |
108 | |
109 | offset = si->lowest_bit; | |
110 | last_in_cluster = offset + SWAPFILE_CLUSTER - 1; | |
111 | ||
112 | /* Locate the first empty (unaligned) cluster */ | |
113 | for (; last_in_cluster <= si->highest_bit; offset++) { | |
1da177e4 | 114 | if (si->swap_map[offset]) |
7dfad418 HD |
115 | last_in_cluster = offset + SWAPFILE_CLUSTER; |
116 | else if (offset == last_in_cluster) { | |
5d337b91 | 117 | spin_lock(&swap_lock); |
9b65ef59 | 118 | si->cluster_next = offset-SWAPFILE_CLUSTER+1; |
7dfad418 | 119 | goto cluster; |
1da177e4 | 120 | } |
048c27fd HD |
121 | if (unlikely(--latency_ration < 0)) { |
122 | cond_resched(); | |
123 | latency_ration = LATENCY_LIMIT; | |
124 | } | |
7dfad418 | 125 | } |
5d337b91 | 126 | spin_lock(&swap_lock); |
7dfad418 | 127 | goto lowest; |
1da177e4 | 128 | } |
7dfad418 HD |
129 | |
130 | si->cluster_nr--; | |
131 | cluster: | |
132 | offset = si->cluster_next; | |
133 | if (offset > si->highest_bit) | |
134 | lowest: offset = si->lowest_bit; | |
52b7efdb HD |
135 | checks: if (!(si->flags & SWP_WRITEOK)) |
136 | goto no_page; | |
7dfad418 HD |
137 | if (!si->highest_bit) |
138 | goto no_page; | |
139 | if (!si->swap_map[offset]) { | |
52b7efdb | 140 | if (offset == si->lowest_bit) |
1da177e4 LT |
141 | si->lowest_bit++; |
142 | if (offset == si->highest_bit) | |
143 | si->highest_bit--; | |
7dfad418 HD |
144 | si->inuse_pages++; |
145 | if (si->inuse_pages == si->pages) { | |
1da177e4 LT |
146 | si->lowest_bit = si->max; |
147 | si->highest_bit = 0; | |
148 | } | |
149 | si->swap_map[offset] = 1; | |
7dfad418 | 150 | si->cluster_next = offset + 1; |
52b7efdb | 151 | si->flags -= SWP_SCANNING; |
1da177e4 LT |
152 | return offset; |
153 | } | |
7dfad418 | 154 | |
5d337b91 | 155 | spin_unlock(&swap_lock); |
7dfad418 | 156 | while (++offset <= si->highest_bit) { |
52b7efdb | 157 | if (!si->swap_map[offset]) { |
5d337b91 | 158 | spin_lock(&swap_lock); |
52b7efdb HD |
159 | goto checks; |
160 | } | |
048c27fd HD |
161 | if (unlikely(--latency_ration < 0)) { |
162 | cond_resched(); | |
163 | latency_ration = LATENCY_LIMIT; | |
164 | } | |
7dfad418 | 165 | } |
5d337b91 | 166 | spin_lock(&swap_lock); |
7dfad418 HD |
167 | goto lowest; |
168 | ||
169 | no_page: | |
52b7efdb | 170 | si->flags -= SWP_SCANNING; |
1da177e4 LT |
171 | return 0; |
172 | } | |
173 | ||
174 | swp_entry_t get_swap_page(void) | |
175 | { | |
fb4f88dc HD |
176 | struct swap_info_struct *si; |
177 | pgoff_t offset; | |
178 | int type, next; | |
179 | int wrapped = 0; | |
1da177e4 | 180 | |
5d337b91 | 181 | spin_lock(&swap_lock); |
1da177e4 | 182 | if (nr_swap_pages <= 0) |
fb4f88dc HD |
183 | goto noswap; |
184 | nr_swap_pages--; | |
185 | ||
186 | for (type = swap_list.next; type >= 0 && wrapped < 2; type = next) { | |
187 | si = swap_info + type; | |
188 | next = si->next; | |
189 | if (next < 0 || | |
190 | (!wrapped && si->prio != swap_info[next].prio)) { | |
191 | next = swap_list.head; | |
192 | wrapped++; | |
1da177e4 | 193 | } |
fb4f88dc HD |
194 | |
195 | if (!si->highest_bit) | |
196 | continue; | |
197 | if (!(si->flags & SWP_WRITEOK)) | |
198 | continue; | |
199 | ||
200 | swap_list.next = next; | |
fb4f88dc | 201 | offset = scan_swap_map(si); |
5d337b91 HD |
202 | if (offset) { |
203 | spin_unlock(&swap_lock); | |
fb4f88dc | 204 | return swp_entry(type, offset); |
5d337b91 | 205 | } |
fb4f88dc | 206 | next = swap_list.next; |
1da177e4 | 207 | } |
fb4f88dc HD |
208 | |
209 | nr_swap_pages++; | |
210 | noswap: | |
5d337b91 | 211 | spin_unlock(&swap_lock); |
fb4f88dc | 212 | return (swp_entry_t) {0}; |
1da177e4 LT |
213 | } |
214 | ||
3a291a20 RW |
215 | swp_entry_t get_swap_page_of_type(int type) |
216 | { | |
217 | struct swap_info_struct *si; | |
218 | pgoff_t offset; | |
219 | ||
220 | spin_lock(&swap_lock); | |
221 | si = swap_info + type; | |
222 | if (si->flags & SWP_WRITEOK) { | |
223 | nr_swap_pages--; | |
224 | offset = scan_swap_map(si); | |
225 | if (offset) { | |
226 | spin_unlock(&swap_lock); | |
227 | return swp_entry(type, offset); | |
228 | } | |
229 | nr_swap_pages++; | |
230 | } | |
231 | spin_unlock(&swap_lock); | |
232 | return (swp_entry_t) {0}; | |
233 | } | |
234 | ||
1da177e4 LT |
235 | static struct swap_info_struct * swap_info_get(swp_entry_t entry) |
236 | { | |
237 | struct swap_info_struct * p; | |
238 | unsigned long offset, type; | |
239 | ||
240 | if (!entry.val) | |
241 | goto out; | |
242 | type = swp_type(entry); | |
243 | if (type >= nr_swapfiles) | |
244 | goto bad_nofile; | |
245 | p = & swap_info[type]; | |
246 | if (!(p->flags & SWP_USED)) | |
247 | goto bad_device; | |
248 | offset = swp_offset(entry); | |
249 | if (offset >= p->max) | |
250 | goto bad_offset; | |
251 | if (!p->swap_map[offset]) | |
252 | goto bad_free; | |
5d337b91 | 253 | spin_lock(&swap_lock); |
1da177e4 LT |
254 | return p; |
255 | ||
256 | bad_free: | |
257 | printk(KERN_ERR "swap_free: %s%08lx\n", Unused_offset, entry.val); | |
258 | goto out; | |
259 | bad_offset: | |
260 | printk(KERN_ERR "swap_free: %s%08lx\n", Bad_offset, entry.val); | |
261 | goto out; | |
262 | bad_device: | |
263 | printk(KERN_ERR "swap_free: %s%08lx\n", Unused_file, entry.val); | |
264 | goto out; | |
265 | bad_nofile: | |
266 | printk(KERN_ERR "swap_free: %s%08lx\n", Bad_file, entry.val); | |
267 | out: | |
268 | return NULL; | |
269 | } | |
270 | ||
1da177e4 LT |
271 | static int swap_entry_free(struct swap_info_struct *p, unsigned long offset) |
272 | { | |
273 | int count = p->swap_map[offset]; | |
274 | ||
275 | if (count < SWAP_MAP_MAX) { | |
276 | count--; | |
277 | p->swap_map[offset] = count; | |
278 | if (!count) { | |
279 | if (offset < p->lowest_bit) | |
280 | p->lowest_bit = offset; | |
281 | if (offset > p->highest_bit) | |
282 | p->highest_bit = offset; | |
89d09a2c HD |
283 | if (p->prio > swap_info[swap_list.next].prio) |
284 | swap_list.next = p - swap_info; | |
1da177e4 LT |
285 | nr_swap_pages++; |
286 | p->inuse_pages--; | |
287 | } | |
288 | } | |
289 | return count; | |
290 | } | |
291 | ||
292 | /* | |
293 | * Caller has made sure that the swapdevice corresponding to entry | |
294 | * is still around or has not been recycled. | |
295 | */ | |
296 | void swap_free(swp_entry_t entry) | |
297 | { | |
298 | struct swap_info_struct * p; | |
299 | ||
300 | p = swap_info_get(entry); | |
301 | if (p) { | |
302 | swap_entry_free(p, swp_offset(entry)); | |
5d337b91 | 303 | spin_unlock(&swap_lock); |
1da177e4 LT |
304 | } |
305 | } | |
306 | ||
307 | /* | |
c475a8ab | 308 | * How many references to page are currently swapped out? |
1da177e4 | 309 | */ |
c475a8ab | 310 | static inline int page_swapcount(struct page *page) |
1da177e4 | 311 | { |
c475a8ab HD |
312 | int count = 0; |
313 | struct swap_info_struct *p; | |
1da177e4 LT |
314 | swp_entry_t entry; |
315 | ||
4c21e2f2 | 316 | entry.val = page_private(page); |
1da177e4 LT |
317 | p = swap_info_get(entry); |
318 | if (p) { | |
c475a8ab HD |
319 | /* Subtract the 1 for the swap cache itself */ |
320 | count = p->swap_map[swp_offset(entry)] - 1; | |
5d337b91 | 321 | spin_unlock(&swap_lock); |
1da177e4 | 322 | } |
c475a8ab | 323 | return count; |
1da177e4 LT |
324 | } |
325 | ||
326 | /* | |
327 | * We can use this swap cache entry directly | |
328 | * if there are no other references to it. | |
1da177e4 LT |
329 | */ |
330 | int can_share_swap_page(struct page *page) | |
331 | { | |
c475a8ab HD |
332 | int count; |
333 | ||
334 | BUG_ON(!PageLocked(page)); | |
335 | count = page_mapcount(page); | |
336 | if (count <= 1 && PageSwapCache(page)) | |
337 | count += page_swapcount(page); | |
338 | return count == 1; | |
1da177e4 LT |
339 | } |
340 | ||
341 | /* | |
342 | * Work out if there are any other processes sharing this | |
343 | * swap cache page. Free it if you can. Return success. | |
344 | */ | |
345 | int remove_exclusive_swap_page(struct page *page) | |
346 | { | |
347 | int retval; | |
348 | struct swap_info_struct * p; | |
349 | swp_entry_t entry; | |
350 | ||
351 | BUG_ON(PagePrivate(page)); | |
352 | BUG_ON(!PageLocked(page)); | |
353 | ||
354 | if (!PageSwapCache(page)) | |
355 | return 0; | |
356 | if (PageWriteback(page)) | |
357 | return 0; | |
358 | if (page_count(page) != 2) /* 2: us + cache */ | |
359 | return 0; | |
360 | ||
4c21e2f2 | 361 | entry.val = page_private(page); |
1da177e4 LT |
362 | p = swap_info_get(entry); |
363 | if (!p) | |
364 | return 0; | |
365 | ||
366 | /* Is the only swap cache user the cache itself? */ | |
367 | retval = 0; | |
368 | if (p->swap_map[swp_offset(entry)] == 1) { | |
369 | /* Recheck the page count with the swapcache lock held.. */ | |
370 | write_lock_irq(&swapper_space.tree_lock); | |
371 | if ((page_count(page) == 2) && !PageWriteback(page)) { | |
372 | __delete_from_swap_cache(page); | |
373 | SetPageDirty(page); | |
374 | retval = 1; | |
375 | } | |
376 | write_unlock_irq(&swapper_space.tree_lock); | |
377 | } | |
5d337b91 | 378 | spin_unlock(&swap_lock); |
1da177e4 LT |
379 | |
380 | if (retval) { | |
381 | swap_free(entry); | |
382 | page_cache_release(page); | |
383 | } | |
384 | ||
385 | return retval; | |
386 | } | |
387 | ||
388 | /* | |
389 | * Free the swap entry like above, but also try to | |
390 | * free the page cache entry if it is the last user. | |
391 | */ | |
392 | void free_swap_and_cache(swp_entry_t entry) | |
393 | { | |
394 | struct swap_info_struct * p; | |
395 | struct page *page = NULL; | |
396 | ||
0697212a CL |
397 | if (is_migration_entry(entry)) |
398 | return; | |
399 | ||
1da177e4 LT |
400 | p = swap_info_get(entry); |
401 | if (p) { | |
93fac704 NP |
402 | if (swap_entry_free(p, swp_offset(entry)) == 1) { |
403 | page = find_get_page(&swapper_space, entry.val); | |
404 | if (page && unlikely(TestSetPageLocked(page))) { | |
405 | page_cache_release(page); | |
406 | page = NULL; | |
407 | } | |
408 | } | |
5d337b91 | 409 | spin_unlock(&swap_lock); |
1da177e4 LT |
410 | } |
411 | if (page) { | |
412 | int one_user; | |
413 | ||
414 | BUG_ON(PagePrivate(page)); | |
1da177e4 LT |
415 | one_user = (page_count(page) == 2); |
416 | /* Only cache user (+us), or swap space full? Free it! */ | |
93fac704 NP |
417 | /* Also recheck PageSwapCache after page is locked (above) */ |
418 | if (PageSwapCache(page) && !PageWriteback(page) && | |
419 | (one_user || vm_swap_full())) { | |
1da177e4 LT |
420 | delete_from_swap_cache(page); |
421 | SetPageDirty(page); | |
422 | } | |
423 | unlock_page(page); | |
424 | page_cache_release(page); | |
425 | } | |
426 | } | |
427 | ||
b0cb1a19 | 428 | #ifdef CONFIG_HIBERNATION |
f577eb30 | 429 | /* |
915bae9e | 430 | * Find the swap type that corresponds to given device (if any). |
f577eb30 | 431 | * |
915bae9e RW |
432 | * @offset - number of the PAGE_SIZE-sized block of the device, starting |
433 | * from 0, in which the swap header is expected to be located. | |
434 | * | |
435 | * This is needed for the suspend to disk (aka swsusp). | |
f577eb30 | 436 | */ |
7bf23687 | 437 | int swap_type_of(dev_t device, sector_t offset, struct block_device **bdev_p) |
f577eb30 | 438 | { |
915bae9e | 439 | struct block_device *bdev = NULL; |
f577eb30 RW |
440 | int i; |
441 | ||
915bae9e RW |
442 | if (device) |
443 | bdev = bdget(device); | |
444 | ||
f577eb30 RW |
445 | spin_lock(&swap_lock); |
446 | for (i = 0; i < nr_swapfiles; i++) { | |
915bae9e | 447 | struct swap_info_struct *sis = swap_info + i; |
f577eb30 | 448 | |
915bae9e | 449 | if (!(sis->flags & SWP_WRITEOK)) |
f577eb30 | 450 | continue; |
b6b5bce3 | 451 | |
915bae9e | 452 | if (!bdev) { |
7bf23687 RW |
453 | if (bdev_p) |
454 | *bdev_p = sis->bdev; | |
455 | ||
6e1819d6 RW |
456 | spin_unlock(&swap_lock); |
457 | return i; | |
458 | } | |
915bae9e RW |
459 | if (bdev == sis->bdev) { |
460 | struct swap_extent *se; | |
461 | ||
462 | se = list_entry(sis->extent_list.next, | |
463 | struct swap_extent, list); | |
464 | if (se->start_block == offset) { | |
7bf23687 RW |
465 | if (bdev_p) |
466 | *bdev_p = sis->bdev; | |
467 | ||
915bae9e RW |
468 | spin_unlock(&swap_lock); |
469 | bdput(bdev); | |
470 | return i; | |
471 | } | |
f577eb30 RW |
472 | } |
473 | } | |
474 | spin_unlock(&swap_lock); | |
915bae9e RW |
475 | if (bdev) |
476 | bdput(bdev); | |
477 | ||
f577eb30 RW |
478 | return -ENODEV; |
479 | } | |
480 | ||
481 | /* | |
482 | * Return either the total number of swap pages of given type, or the number | |
483 | * of free pages of that type (depending on @free) | |
484 | * | |
485 | * This is needed for software suspend | |
486 | */ | |
487 | unsigned int count_swap_pages(int type, int free) | |
488 | { | |
489 | unsigned int n = 0; | |
490 | ||
491 | if (type < nr_swapfiles) { | |
492 | spin_lock(&swap_lock); | |
493 | if (swap_info[type].flags & SWP_WRITEOK) { | |
494 | n = swap_info[type].pages; | |
495 | if (free) | |
496 | n -= swap_info[type].inuse_pages; | |
497 | } | |
498 | spin_unlock(&swap_lock); | |
499 | } | |
500 | return n; | |
501 | } | |
502 | #endif | |
503 | ||
1da177e4 | 504 | /* |
72866f6f HD |
505 | * No need to decide whether this PTE shares the swap entry with others, |
506 | * just let do_wp_page work it out if a write is requested later - to | |
507 | * force COW, vm_page_prot omits write permission from any private vma. | |
1da177e4 | 508 | */ |
2e441889 | 509 | static int unuse_pte(struct vm_area_struct *vma, pmd_t *pmd, |
1da177e4 LT |
510 | unsigned long addr, swp_entry_t entry, struct page *page) |
511 | { | |
2e441889 HD |
512 | spinlock_t *ptl; |
513 | pte_t *pte; | |
514 | int found = 1; | |
515 | ||
516 | pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl); | |
517 | if (unlikely(!pte_same(*pte, swp_entry_to_pte(entry)))) { | |
518 | found = 0; | |
519 | goto out; | |
520 | } | |
521 | ||
4294621f | 522 | inc_mm_counter(vma->vm_mm, anon_rss); |
1da177e4 LT |
523 | get_page(page); |
524 | set_pte_at(vma->vm_mm, addr, pte, | |
525 | pte_mkold(mk_pte(page, vma->vm_page_prot))); | |
526 | page_add_anon_rmap(page, vma, addr); | |
527 | swap_free(entry); | |
528 | /* | |
529 | * Move the page to the active list so it is not | |
530 | * immediately swapped out again after swapon. | |
531 | */ | |
532 | activate_page(page); | |
2e441889 HD |
533 | out: |
534 | pte_unmap_unlock(pte, ptl); | |
535 | return found; | |
1da177e4 LT |
536 | } |
537 | ||
538 | static int unuse_pte_range(struct vm_area_struct *vma, pmd_t *pmd, | |
539 | unsigned long addr, unsigned long end, | |
540 | swp_entry_t entry, struct page *page) | |
541 | { | |
1da177e4 | 542 | pte_t swp_pte = swp_entry_to_pte(entry); |
705e87c0 | 543 | pte_t *pte; |
705e87c0 | 544 | int found = 0; |
1da177e4 | 545 | |
2e441889 HD |
546 | /* |
547 | * We don't actually need pte lock while scanning for swp_pte: since | |
548 | * we hold page lock and mmap_sem, swp_pte cannot be inserted into the | |
549 | * page table while we're scanning; though it could get zapped, and on | |
550 | * some architectures (e.g. x86_32 with PAE) we might catch a glimpse | |
551 | * of unmatched parts which look like swp_pte, so unuse_pte must | |
552 | * recheck under pte lock. Scanning without pte lock lets it be | |
553 | * preemptible whenever CONFIG_PREEMPT but not CONFIG_HIGHPTE. | |
554 | */ | |
555 | pte = pte_offset_map(pmd, addr); | |
1da177e4 LT |
556 | do { |
557 | /* | |
558 | * swapoff spends a _lot_ of time in this loop! | |
559 | * Test inline before going to call unuse_pte. | |
560 | */ | |
561 | if (unlikely(pte_same(*pte, swp_pte))) { | |
2e441889 HD |
562 | pte_unmap(pte); |
563 | found = unuse_pte(vma, pmd, addr, entry, page); | |
564 | if (found) | |
565 | goto out; | |
566 | pte = pte_offset_map(pmd, addr); | |
1da177e4 LT |
567 | } |
568 | } while (pte++, addr += PAGE_SIZE, addr != end); | |
2e441889 HD |
569 | pte_unmap(pte - 1); |
570 | out: | |
705e87c0 | 571 | return found; |
1da177e4 LT |
572 | } |
573 | ||
574 | static inline int unuse_pmd_range(struct vm_area_struct *vma, pud_t *pud, | |
575 | unsigned long addr, unsigned long end, | |
576 | swp_entry_t entry, struct page *page) | |
577 | { | |
578 | pmd_t *pmd; | |
579 | unsigned long next; | |
580 | ||
581 | pmd = pmd_offset(pud, addr); | |
582 | do { | |
583 | next = pmd_addr_end(addr, end); | |
584 | if (pmd_none_or_clear_bad(pmd)) | |
585 | continue; | |
586 | if (unuse_pte_range(vma, pmd, addr, next, entry, page)) | |
587 | return 1; | |
588 | } while (pmd++, addr = next, addr != end); | |
589 | return 0; | |
590 | } | |
591 | ||
592 | static inline int unuse_pud_range(struct vm_area_struct *vma, pgd_t *pgd, | |
593 | unsigned long addr, unsigned long end, | |
594 | swp_entry_t entry, struct page *page) | |
595 | { | |
596 | pud_t *pud; | |
597 | unsigned long next; | |
598 | ||
599 | pud = pud_offset(pgd, addr); | |
600 | do { | |
601 | next = pud_addr_end(addr, end); | |
602 | if (pud_none_or_clear_bad(pud)) | |
603 | continue; | |
604 | if (unuse_pmd_range(vma, pud, addr, next, entry, page)) | |
605 | return 1; | |
606 | } while (pud++, addr = next, addr != end); | |
607 | return 0; | |
608 | } | |
609 | ||
610 | static int unuse_vma(struct vm_area_struct *vma, | |
611 | swp_entry_t entry, struct page *page) | |
612 | { | |
613 | pgd_t *pgd; | |
614 | unsigned long addr, end, next; | |
615 | ||
616 | if (page->mapping) { | |
617 | addr = page_address_in_vma(page, vma); | |
618 | if (addr == -EFAULT) | |
619 | return 0; | |
620 | else | |
621 | end = addr + PAGE_SIZE; | |
622 | } else { | |
623 | addr = vma->vm_start; | |
624 | end = vma->vm_end; | |
625 | } | |
626 | ||
627 | pgd = pgd_offset(vma->vm_mm, addr); | |
628 | do { | |
629 | next = pgd_addr_end(addr, end); | |
630 | if (pgd_none_or_clear_bad(pgd)) | |
631 | continue; | |
632 | if (unuse_pud_range(vma, pgd, addr, next, entry, page)) | |
633 | return 1; | |
634 | } while (pgd++, addr = next, addr != end); | |
635 | return 0; | |
636 | } | |
637 | ||
638 | static int unuse_mm(struct mm_struct *mm, | |
639 | swp_entry_t entry, struct page *page) | |
640 | { | |
641 | struct vm_area_struct *vma; | |
642 | ||
643 | if (!down_read_trylock(&mm->mmap_sem)) { | |
644 | /* | |
c475a8ab HD |
645 | * Activate page so shrink_cache is unlikely to unmap its |
646 | * ptes while lock is dropped, so swapoff can make progress. | |
1da177e4 | 647 | */ |
c475a8ab | 648 | activate_page(page); |
1da177e4 LT |
649 | unlock_page(page); |
650 | down_read(&mm->mmap_sem); | |
651 | lock_page(page); | |
652 | } | |
1da177e4 LT |
653 | for (vma = mm->mmap; vma; vma = vma->vm_next) { |
654 | if (vma->anon_vma && unuse_vma(vma, entry, page)) | |
655 | break; | |
656 | } | |
1da177e4 LT |
657 | up_read(&mm->mmap_sem); |
658 | /* | |
659 | * Currently unuse_mm cannot fail, but leave error handling | |
660 | * at call sites for now, since we change it from time to time. | |
661 | */ | |
662 | return 0; | |
663 | } | |
664 | ||
665 | /* | |
666 | * Scan swap_map from current position to next entry still in use. | |
667 | * Recycle to start on reaching the end, returning 0 when empty. | |
668 | */ | |
6eb396dc HD |
669 | static unsigned int find_next_to_unuse(struct swap_info_struct *si, |
670 | unsigned int prev) | |
1da177e4 | 671 | { |
6eb396dc HD |
672 | unsigned int max = si->max; |
673 | unsigned int i = prev; | |
1da177e4 LT |
674 | int count; |
675 | ||
676 | /* | |
5d337b91 | 677 | * No need for swap_lock here: we're just looking |
1da177e4 LT |
678 | * for whether an entry is in use, not modifying it; false |
679 | * hits are okay, and sys_swapoff() has already prevented new | |
5d337b91 | 680 | * allocations from this area (while holding swap_lock). |
1da177e4 LT |
681 | */ |
682 | for (;;) { | |
683 | if (++i >= max) { | |
684 | if (!prev) { | |
685 | i = 0; | |
686 | break; | |
687 | } | |
688 | /* | |
689 | * No entries in use at top of swap_map, | |
690 | * loop back to start and recheck there. | |
691 | */ | |
692 | max = prev + 1; | |
693 | prev = 0; | |
694 | i = 1; | |
695 | } | |
696 | count = si->swap_map[i]; | |
697 | if (count && count != SWAP_MAP_BAD) | |
698 | break; | |
699 | } | |
700 | return i; | |
701 | } | |
702 | ||
703 | /* | |
704 | * We completely avoid races by reading each swap page in advance, | |
705 | * and then search for the process using it. All the necessary | |
706 | * page table adjustments can then be made atomically. | |
707 | */ | |
708 | static int try_to_unuse(unsigned int type) | |
709 | { | |
710 | struct swap_info_struct * si = &swap_info[type]; | |
711 | struct mm_struct *start_mm; | |
712 | unsigned short *swap_map; | |
713 | unsigned short swcount; | |
714 | struct page *page; | |
715 | swp_entry_t entry; | |
6eb396dc | 716 | unsigned int i = 0; |
1da177e4 LT |
717 | int retval = 0; |
718 | int reset_overflow = 0; | |
719 | int shmem; | |
720 | ||
721 | /* | |
722 | * When searching mms for an entry, a good strategy is to | |
723 | * start at the first mm we freed the previous entry from | |
724 | * (though actually we don't notice whether we or coincidence | |
725 | * freed the entry). Initialize this start_mm with a hold. | |
726 | * | |
727 | * A simpler strategy would be to start at the last mm we | |
728 | * freed the previous entry from; but that would take less | |
729 | * advantage of mmlist ordering, which clusters forked mms | |
730 | * together, child after parent. If we race with dup_mmap(), we | |
731 | * prefer to resolve parent before child, lest we miss entries | |
732 | * duplicated after we scanned child: using last mm would invert | |
733 | * that. Though it's only a serious concern when an overflowed | |
734 | * swap count is reset from SWAP_MAP_MAX, preventing a rescan. | |
735 | */ | |
736 | start_mm = &init_mm; | |
737 | atomic_inc(&init_mm.mm_users); | |
738 | ||
739 | /* | |
740 | * Keep on scanning until all entries have gone. Usually, | |
741 | * one pass through swap_map is enough, but not necessarily: | |
742 | * there are races when an instance of an entry might be missed. | |
743 | */ | |
744 | while ((i = find_next_to_unuse(si, i)) != 0) { | |
745 | if (signal_pending(current)) { | |
746 | retval = -EINTR; | |
747 | break; | |
748 | } | |
749 | ||
750 | /* | |
751 | * Get a page for the entry, using the existing swap | |
752 | * cache page if there is one. Otherwise, get a clean | |
753 | * page and read the swap into it. | |
754 | */ | |
755 | swap_map = &si->swap_map[i]; | |
756 | entry = swp_entry(type, i); | |
02098fea HD |
757 | page = read_swap_cache_async(entry, |
758 | GFP_HIGHUSER_MOVABLE, NULL, 0); | |
1da177e4 LT |
759 | if (!page) { |
760 | /* | |
761 | * Either swap_duplicate() failed because entry | |
762 | * has been freed independently, and will not be | |
763 | * reused since sys_swapoff() already disabled | |
764 | * allocation from here, or alloc_page() failed. | |
765 | */ | |
766 | if (!*swap_map) | |
767 | continue; | |
768 | retval = -ENOMEM; | |
769 | break; | |
770 | } | |
771 | ||
772 | /* | |
773 | * Don't hold on to start_mm if it looks like exiting. | |
774 | */ | |
775 | if (atomic_read(&start_mm->mm_users) == 1) { | |
776 | mmput(start_mm); | |
777 | start_mm = &init_mm; | |
778 | atomic_inc(&init_mm.mm_users); | |
779 | } | |
780 | ||
781 | /* | |
782 | * Wait for and lock page. When do_swap_page races with | |
783 | * try_to_unuse, do_swap_page can handle the fault much | |
784 | * faster than try_to_unuse can locate the entry. This | |
785 | * apparently redundant "wait_on_page_locked" lets try_to_unuse | |
786 | * defer to do_swap_page in such a case - in some tests, | |
787 | * do_swap_page and try_to_unuse repeatedly compete. | |
788 | */ | |
789 | wait_on_page_locked(page); | |
790 | wait_on_page_writeback(page); | |
791 | lock_page(page); | |
792 | wait_on_page_writeback(page); | |
793 | ||
794 | /* | |
795 | * Remove all references to entry. | |
796 | * Whenever we reach init_mm, there's no address space | |
797 | * to search, but use it as a reminder to search shmem. | |
798 | */ | |
799 | shmem = 0; | |
800 | swcount = *swap_map; | |
801 | if (swcount > 1) { | |
802 | if (start_mm == &init_mm) | |
803 | shmem = shmem_unuse(entry, page); | |
804 | else | |
805 | retval = unuse_mm(start_mm, entry, page); | |
806 | } | |
807 | if (*swap_map > 1) { | |
808 | int set_start_mm = (*swap_map >= swcount); | |
809 | struct list_head *p = &start_mm->mmlist; | |
810 | struct mm_struct *new_start_mm = start_mm; | |
811 | struct mm_struct *prev_mm = start_mm; | |
812 | struct mm_struct *mm; | |
813 | ||
814 | atomic_inc(&new_start_mm->mm_users); | |
815 | atomic_inc(&prev_mm->mm_users); | |
816 | spin_lock(&mmlist_lock); | |
2e0e26c7 | 817 | while (*swap_map > 1 && !retval && !shmem && |
1da177e4 LT |
818 | (p = p->next) != &start_mm->mmlist) { |
819 | mm = list_entry(p, struct mm_struct, mmlist); | |
70af7c5c | 820 | if (!atomic_inc_not_zero(&mm->mm_users)) |
1da177e4 | 821 | continue; |
1da177e4 LT |
822 | spin_unlock(&mmlist_lock); |
823 | mmput(prev_mm); | |
824 | prev_mm = mm; | |
825 | ||
826 | cond_resched(); | |
827 | ||
828 | swcount = *swap_map; | |
829 | if (swcount <= 1) | |
830 | ; | |
831 | else if (mm == &init_mm) { | |
832 | set_start_mm = 1; | |
833 | shmem = shmem_unuse(entry, page); | |
834 | } else | |
835 | retval = unuse_mm(mm, entry, page); | |
836 | if (set_start_mm && *swap_map < swcount) { | |
837 | mmput(new_start_mm); | |
838 | atomic_inc(&mm->mm_users); | |
839 | new_start_mm = mm; | |
840 | set_start_mm = 0; | |
841 | } | |
842 | spin_lock(&mmlist_lock); | |
843 | } | |
844 | spin_unlock(&mmlist_lock); | |
845 | mmput(prev_mm); | |
846 | mmput(start_mm); | |
847 | start_mm = new_start_mm; | |
848 | } | |
2e0e26c7 HD |
849 | if (shmem) { |
850 | /* page has already been unlocked and released */ | |
851 | if (shmem > 0) | |
852 | continue; | |
853 | retval = shmem; | |
854 | break; | |
855 | } | |
1da177e4 LT |
856 | if (retval) { |
857 | unlock_page(page); | |
858 | page_cache_release(page); | |
859 | break; | |
860 | } | |
861 | ||
862 | /* | |
863 | * How could swap count reach 0x7fff when the maximum | |
864 | * pid is 0x7fff, and there's no way to repeat a swap | |
865 | * page within an mm (except in shmem, where it's the | |
866 | * shared object which takes the reference count)? | |
867 | * We believe SWAP_MAP_MAX cannot occur in Linux 2.4. | |
868 | * | |
869 | * If that's wrong, then we should worry more about | |
870 | * exit_mmap() and do_munmap() cases described above: | |
871 | * we might be resetting SWAP_MAP_MAX too early here. | |
872 | * We know "Undead"s can happen, they're okay, so don't | |
873 | * report them; but do report if we reset SWAP_MAP_MAX. | |
874 | */ | |
875 | if (*swap_map == SWAP_MAP_MAX) { | |
5d337b91 | 876 | spin_lock(&swap_lock); |
1da177e4 | 877 | *swap_map = 1; |
5d337b91 | 878 | spin_unlock(&swap_lock); |
1da177e4 LT |
879 | reset_overflow = 1; |
880 | } | |
881 | ||
882 | /* | |
883 | * If a reference remains (rare), we would like to leave | |
884 | * the page in the swap cache; but try_to_unmap could | |
885 | * then re-duplicate the entry once we drop page lock, | |
886 | * so we might loop indefinitely; also, that page could | |
887 | * not be swapped out to other storage meanwhile. So: | |
888 | * delete from cache even if there's another reference, | |
889 | * after ensuring that the data has been saved to disk - | |
890 | * since if the reference remains (rarer), it will be | |
891 | * read from disk into another page. Splitting into two | |
892 | * pages would be incorrect if swap supported "shared | |
893 | * private" pages, but they are handled by tmpfs files. | |
1da177e4 LT |
894 | */ |
895 | if ((*swap_map > 1) && PageDirty(page) && PageSwapCache(page)) { | |
896 | struct writeback_control wbc = { | |
897 | .sync_mode = WB_SYNC_NONE, | |
898 | }; | |
899 | ||
900 | swap_writepage(page, &wbc); | |
901 | lock_page(page); | |
902 | wait_on_page_writeback(page); | |
903 | } | |
2e0e26c7 HD |
904 | if (PageSwapCache(page)) |
905 | delete_from_swap_cache(page); | |
1da177e4 LT |
906 | |
907 | /* | |
908 | * So we could skip searching mms once swap count went | |
909 | * to 1, we did not mark any present ptes as dirty: must | |
2706a1b8 | 910 | * mark page dirty so shrink_page_list will preserve it. |
1da177e4 LT |
911 | */ |
912 | SetPageDirty(page); | |
913 | unlock_page(page); | |
914 | page_cache_release(page); | |
915 | ||
916 | /* | |
917 | * Make sure that we aren't completely killing | |
918 | * interactive performance. | |
919 | */ | |
920 | cond_resched(); | |
921 | } | |
922 | ||
923 | mmput(start_mm); | |
924 | if (reset_overflow) { | |
925 | printk(KERN_WARNING "swapoff: cleared swap entry overflow\n"); | |
926 | swap_overflow = 0; | |
927 | } | |
928 | return retval; | |
929 | } | |
930 | ||
931 | /* | |
5d337b91 HD |
932 | * After a successful try_to_unuse, if no swap is now in use, we know |
933 | * we can empty the mmlist. swap_lock must be held on entry and exit. | |
934 | * Note that mmlist_lock nests inside swap_lock, and an mm must be | |
1da177e4 LT |
935 | * added to the mmlist just after page_duplicate - before would be racy. |
936 | */ | |
937 | static void drain_mmlist(void) | |
938 | { | |
939 | struct list_head *p, *next; | |
940 | unsigned int i; | |
941 | ||
942 | for (i = 0; i < nr_swapfiles; i++) | |
943 | if (swap_info[i].inuse_pages) | |
944 | return; | |
945 | spin_lock(&mmlist_lock); | |
946 | list_for_each_safe(p, next, &init_mm.mmlist) | |
947 | list_del_init(p); | |
948 | spin_unlock(&mmlist_lock); | |
949 | } | |
950 | ||
951 | /* | |
952 | * Use this swapdev's extent info to locate the (PAGE_SIZE) block which | |
953 | * corresponds to page offset `offset'. | |
954 | */ | |
955 | sector_t map_swap_page(struct swap_info_struct *sis, pgoff_t offset) | |
956 | { | |
957 | struct swap_extent *se = sis->curr_swap_extent; | |
958 | struct swap_extent *start_se = se; | |
959 | ||
960 | for ( ; ; ) { | |
961 | struct list_head *lh; | |
962 | ||
963 | if (se->start_page <= offset && | |
964 | offset < (se->start_page + se->nr_pages)) { | |
965 | return se->start_block + (offset - se->start_page); | |
966 | } | |
11d31886 | 967 | lh = se->list.next; |
1da177e4 | 968 | if (lh == &sis->extent_list) |
11d31886 | 969 | lh = lh->next; |
1da177e4 LT |
970 | se = list_entry(lh, struct swap_extent, list); |
971 | sis->curr_swap_extent = se; | |
972 | BUG_ON(se == start_se); /* It *must* be present */ | |
973 | } | |
974 | } | |
975 | ||
b0cb1a19 | 976 | #ifdef CONFIG_HIBERNATION |
3aef83e0 RW |
977 | /* |
978 | * Get the (PAGE_SIZE) block corresponding to given offset on the swapdev | |
979 | * corresponding to given index in swap_info (swap type). | |
980 | */ | |
981 | sector_t swapdev_block(int swap_type, pgoff_t offset) | |
982 | { | |
983 | struct swap_info_struct *sis; | |
984 | ||
985 | if (swap_type >= nr_swapfiles) | |
986 | return 0; | |
987 | ||
988 | sis = swap_info + swap_type; | |
989 | return (sis->flags & SWP_WRITEOK) ? map_swap_page(sis, offset) : 0; | |
990 | } | |
b0cb1a19 | 991 | #endif /* CONFIG_HIBERNATION */ |
3aef83e0 | 992 | |
1da177e4 LT |
993 | /* |
994 | * Free all of a swapdev's extent information | |
995 | */ | |
996 | static void destroy_swap_extents(struct swap_info_struct *sis) | |
997 | { | |
998 | while (!list_empty(&sis->extent_list)) { | |
999 | struct swap_extent *se; | |
1000 | ||
1001 | se = list_entry(sis->extent_list.next, | |
1002 | struct swap_extent, list); | |
1003 | list_del(&se->list); | |
1004 | kfree(se); | |
1005 | } | |
1da177e4 LT |
1006 | } |
1007 | ||
1008 | /* | |
1009 | * Add a block range (and the corresponding page range) into this swapdev's | |
11d31886 | 1010 | * extent list. The extent list is kept sorted in page order. |
1da177e4 | 1011 | * |
11d31886 | 1012 | * This function rather assumes that it is called in ascending page order. |
1da177e4 LT |
1013 | */ |
1014 | static int | |
1015 | add_swap_extent(struct swap_info_struct *sis, unsigned long start_page, | |
1016 | unsigned long nr_pages, sector_t start_block) | |
1017 | { | |
1018 | struct swap_extent *se; | |
1019 | struct swap_extent *new_se; | |
1020 | struct list_head *lh; | |
1021 | ||
11d31886 HD |
1022 | lh = sis->extent_list.prev; /* The highest page extent */ |
1023 | if (lh != &sis->extent_list) { | |
1da177e4 | 1024 | se = list_entry(lh, struct swap_extent, list); |
11d31886 HD |
1025 | BUG_ON(se->start_page + se->nr_pages != start_page); |
1026 | if (se->start_block + se->nr_pages == start_block) { | |
1da177e4 LT |
1027 | /* Merge it */ |
1028 | se->nr_pages += nr_pages; | |
1029 | return 0; | |
1030 | } | |
1da177e4 LT |
1031 | } |
1032 | ||
1033 | /* | |
1034 | * No merge. Insert a new extent, preserving ordering. | |
1035 | */ | |
1036 | new_se = kmalloc(sizeof(*se), GFP_KERNEL); | |
1037 | if (new_se == NULL) | |
1038 | return -ENOMEM; | |
1039 | new_se->start_page = start_page; | |
1040 | new_se->nr_pages = nr_pages; | |
1041 | new_se->start_block = start_block; | |
1042 | ||
11d31886 | 1043 | list_add_tail(&new_se->list, &sis->extent_list); |
53092a74 | 1044 | return 1; |
1da177e4 LT |
1045 | } |
1046 | ||
1047 | /* | |
1048 | * A `swap extent' is a simple thing which maps a contiguous range of pages | |
1049 | * onto a contiguous range of disk blocks. An ordered list of swap extents | |
1050 | * is built at swapon time and is then used at swap_writepage/swap_readpage | |
1051 | * time for locating where on disk a page belongs. | |
1052 | * | |
1053 | * If the swapfile is an S_ISBLK block device, a single extent is installed. | |
1054 | * This is done so that the main operating code can treat S_ISBLK and S_ISREG | |
1055 | * swap files identically. | |
1056 | * | |
1057 | * Whether the swapdev is an S_ISREG file or an S_ISBLK blockdev, the swap | |
1058 | * extent list operates in PAGE_SIZE disk blocks. Both S_ISREG and S_ISBLK | |
1059 | * swapfiles are handled *identically* after swapon time. | |
1060 | * | |
1061 | * For S_ISREG swapfiles, setup_swap_extents() will walk all the file's blocks | |
1062 | * and will parse them into an ordered extent list, in PAGE_SIZE chunks. If | |
1063 | * some stray blocks are found which do not fall within the PAGE_SIZE alignment | |
1064 | * requirements, they are simply tossed out - we will never use those blocks | |
1065 | * for swapping. | |
1066 | * | |
b0d9bcd4 | 1067 | * For S_ISREG swapfiles we set S_SWAPFILE across the life of the swapon. This |
1da177e4 LT |
1068 | * prevents root from shooting her foot off by ftruncating an in-use swapfile, |
1069 | * which will scribble on the fs. | |
1070 | * | |
1071 | * The amount of disk space which a single swap extent represents varies. | |
1072 | * Typically it is in the 1-4 megabyte range. So we can have hundreds of | |
1073 | * extents in the list. To avoid much list walking, we cache the previous | |
1074 | * search location in `curr_swap_extent', and start new searches from there. | |
1075 | * This is extremely effective. The average number of iterations in | |
1076 | * map_swap_page() has been measured at about 0.3 per page. - akpm. | |
1077 | */ | |
53092a74 | 1078 | static int setup_swap_extents(struct swap_info_struct *sis, sector_t *span) |
1da177e4 LT |
1079 | { |
1080 | struct inode *inode; | |
1081 | unsigned blocks_per_page; | |
1082 | unsigned long page_no; | |
1083 | unsigned blkbits; | |
1084 | sector_t probe_block; | |
1085 | sector_t last_block; | |
53092a74 HD |
1086 | sector_t lowest_block = -1; |
1087 | sector_t highest_block = 0; | |
1088 | int nr_extents = 0; | |
1da177e4 LT |
1089 | int ret; |
1090 | ||
1091 | inode = sis->swap_file->f_mapping->host; | |
1092 | if (S_ISBLK(inode->i_mode)) { | |
1093 | ret = add_swap_extent(sis, 0, sis->max, 0); | |
53092a74 | 1094 | *span = sis->pages; |
1da177e4 LT |
1095 | goto done; |
1096 | } | |
1097 | ||
1098 | blkbits = inode->i_blkbits; | |
1099 | blocks_per_page = PAGE_SIZE >> blkbits; | |
1100 | ||
1101 | /* | |
1102 | * Map all the blocks into the extent list. This code doesn't try | |
1103 | * to be very smart. | |
1104 | */ | |
1105 | probe_block = 0; | |
1106 | page_no = 0; | |
1107 | last_block = i_size_read(inode) >> blkbits; | |
1108 | while ((probe_block + blocks_per_page) <= last_block && | |
1109 | page_no < sis->max) { | |
1110 | unsigned block_in_page; | |
1111 | sector_t first_block; | |
1112 | ||
1113 | first_block = bmap(inode, probe_block); | |
1114 | if (first_block == 0) | |
1115 | goto bad_bmap; | |
1116 | ||
1117 | /* | |
1118 | * It must be PAGE_SIZE aligned on-disk | |
1119 | */ | |
1120 | if (first_block & (blocks_per_page - 1)) { | |
1121 | probe_block++; | |
1122 | goto reprobe; | |
1123 | } | |
1124 | ||
1125 | for (block_in_page = 1; block_in_page < blocks_per_page; | |
1126 | block_in_page++) { | |
1127 | sector_t block; | |
1128 | ||
1129 | block = bmap(inode, probe_block + block_in_page); | |
1130 | if (block == 0) | |
1131 | goto bad_bmap; | |
1132 | if (block != first_block + block_in_page) { | |
1133 | /* Discontiguity */ | |
1134 | probe_block++; | |
1135 | goto reprobe; | |
1136 | } | |
1137 | } | |
1138 | ||
53092a74 HD |
1139 | first_block >>= (PAGE_SHIFT - blkbits); |
1140 | if (page_no) { /* exclude the header page */ | |
1141 | if (first_block < lowest_block) | |
1142 | lowest_block = first_block; | |
1143 | if (first_block > highest_block) | |
1144 | highest_block = first_block; | |
1145 | } | |
1146 | ||
1da177e4 LT |
1147 | /* |
1148 | * We found a PAGE_SIZE-length, PAGE_SIZE-aligned run of blocks | |
1149 | */ | |
53092a74 HD |
1150 | ret = add_swap_extent(sis, page_no, 1, first_block); |
1151 | if (ret < 0) | |
1da177e4 | 1152 | goto out; |
53092a74 | 1153 | nr_extents += ret; |
1da177e4 LT |
1154 | page_no++; |
1155 | probe_block += blocks_per_page; | |
1156 | reprobe: | |
1157 | continue; | |
1158 | } | |
53092a74 HD |
1159 | ret = nr_extents; |
1160 | *span = 1 + highest_block - lowest_block; | |
1da177e4 | 1161 | if (page_no == 0) |
e2244ec2 | 1162 | page_no = 1; /* force Empty message */ |
1da177e4 | 1163 | sis->max = page_no; |
e2244ec2 | 1164 | sis->pages = page_no - 1; |
1da177e4 LT |
1165 | sis->highest_bit = page_no - 1; |
1166 | done: | |
1167 | sis->curr_swap_extent = list_entry(sis->extent_list.prev, | |
1168 | struct swap_extent, list); | |
1169 | goto out; | |
1170 | bad_bmap: | |
1171 | printk(KERN_ERR "swapon: swapfile has holes\n"); | |
1172 | ret = -EINVAL; | |
1173 | out: | |
1174 | return ret; | |
1175 | } | |
1176 | ||
1177 | #if 0 /* We don't need this yet */ | |
1178 | #include <linux/backing-dev.h> | |
1179 | int page_queue_congested(struct page *page) | |
1180 | { | |
1181 | struct backing_dev_info *bdi; | |
1182 | ||
1183 | BUG_ON(!PageLocked(page)); /* It pins the swap_info_struct */ | |
1184 | ||
1185 | if (PageSwapCache(page)) { | |
4c21e2f2 | 1186 | swp_entry_t entry = { .val = page_private(page) }; |
1da177e4 LT |
1187 | struct swap_info_struct *sis; |
1188 | ||
1189 | sis = get_swap_info_struct(swp_type(entry)); | |
1190 | bdi = sis->bdev->bd_inode->i_mapping->backing_dev_info; | |
1191 | } else | |
1192 | bdi = page->mapping->backing_dev_info; | |
1193 | return bdi_write_congested(bdi); | |
1194 | } | |
1195 | #endif | |
1196 | ||
1197 | asmlinkage long sys_swapoff(const char __user * specialfile) | |
1198 | { | |
1199 | struct swap_info_struct * p = NULL; | |
1200 | unsigned short *swap_map; | |
1201 | struct file *swap_file, *victim; | |
1202 | struct address_space *mapping; | |
1203 | struct inode *inode; | |
1204 | char * pathname; | |
1205 | int i, type, prev; | |
1206 | int err; | |
1207 | ||
1208 | if (!capable(CAP_SYS_ADMIN)) | |
1209 | return -EPERM; | |
1210 | ||
1211 | pathname = getname(specialfile); | |
1212 | err = PTR_ERR(pathname); | |
1213 | if (IS_ERR(pathname)) | |
1214 | goto out; | |
1215 | ||
1216 | victim = filp_open(pathname, O_RDWR|O_LARGEFILE, 0); | |
1217 | putname(pathname); | |
1218 | err = PTR_ERR(victim); | |
1219 | if (IS_ERR(victim)) | |
1220 | goto out; | |
1221 | ||
1222 | mapping = victim->f_mapping; | |
1223 | prev = -1; | |
5d337b91 | 1224 | spin_lock(&swap_lock); |
1da177e4 LT |
1225 | for (type = swap_list.head; type >= 0; type = swap_info[type].next) { |
1226 | p = swap_info + type; | |
1227 | if ((p->flags & SWP_ACTIVE) == SWP_ACTIVE) { | |
1228 | if (p->swap_file->f_mapping == mapping) | |
1229 | break; | |
1230 | } | |
1231 | prev = type; | |
1232 | } | |
1233 | if (type < 0) { | |
1234 | err = -EINVAL; | |
5d337b91 | 1235 | spin_unlock(&swap_lock); |
1da177e4 LT |
1236 | goto out_dput; |
1237 | } | |
1238 | if (!security_vm_enough_memory(p->pages)) | |
1239 | vm_unacct_memory(p->pages); | |
1240 | else { | |
1241 | err = -ENOMEM; | |
5d337b91 | 1242 | spin_unlock(&swap_lock); |
1da177e4 LT |
1243 | goto out_dput; |
1244 | } | |
1245 | if (prev < 0) { | |
1246 | swap_list.head = p->next; | |
1247 | } else { | |
1248 | swap_info[prev].next = p->next; | |
1249 | } | |
1250 | if (type == swap_list.next) { | |
1251 | /* just pick something that's safe... */ | |
1252 | swap_list.next = swap_list.head; | |
1253 | } | |
1254 | nr_swap_pages -= p->pages; | |
1255 | total_swap_pages -= p->pages; | |
1256 | p->flags &= ~SWP_WRITEOK; | |
5d337b91 | 1257 | spin_unlock(&swap_lock); |
fb4f88dc | 1258 | |
1da177e4 LT |
1259 | current->flags |= PF_SWAPOFF; |
1260 | err = try_to_unuse(type); | |
1261 | current->flags &= ~PF_SWAPOFF; | |
1262 | ||
1da177e4 LT |
1263 | if (err) { |
1264 | /* re-insert swap space back into swap_list */ | |
5d337b91 | 1265 | spin_lock(&swap_lock); |
1da177e4 LT |
1266 | for (prev = -1, i = swap_list.head; i >= 0; prev = i, i = swap_info[i].next) |
1267 | if (p->prio >= swap_info[i].prio) | |
1268 | break; | |
1269 | p->next = i; | |
1270 | if (prev < 0) | |
1271 | swap_list.head = swap_list.next = p - swap_info; | |
1272 | else | |
1273 | swap_info[prev].next = p - swap_info; | |
1274 | nr_swap_pages += p->pages; | |
1275 | total_swap_pages += p->pages; | |
1276 | p->flags |= SWP_WRITEOK; | |
5d337b91 | 1277 | spin_unlock(&swap_lock); |
1da177e4 LT |
1278 | goto out_dput; |
1279 | } | |
52b7efdb HD |
1280 | |
1281 | /* wait for any unplug function to finish */ | |
1282 | down_write(&swap_unplug_sem); | |
1283 | up_write(&swap_unplug_sem); | |
1284 | ||
5d337b91 | 1285 | destroy_swap_extents(p); |
fc0abb14 | 1286 | mutex_lock(&swapon_mutex); |
5d337b91 HD |
1287 | spin_lock(&swap_lock); |
1288 | drain_mmlist(); | |
1289 | ||
52b7efdb | 1290 | /* wait for anyone still in scan_swap_map */ |
52b7efdb HD |
1291 | p->highest_bit = 0; /* cuts scans short */ |
1292 | while (p->flags >= SWP_SCANNING) { | |
5d337b91 | 1293 | spin_unlock(&swap_lock); |
13e4b57f | 1294 | schedule_timeout_uninterruptible(1); |
5d337b91 | 1295 | spin_lock(&swap_lock); |
52b7efdb | 1296 | } |
52b7efdb | 1297 | |
1da177e4 LT |
1298 | swap_file = p->swap_file; |
1299 | p->swap_file = NULL; | |
1300 | p->max = 0; | |
1301 | swap_map = p->swap_map; | |
1302 | p->swap_map = NULL; | |
1303 | p->flags = 0; | |
5d337b91 | 1304 | spin_unlock(&swap_lock); |
fc0abb14 | 1305 | mutex_unlock(&swapon_mutex); |
1da177e4 LT |
1306 | vfree(swap_map); |
1307 | inode = mapping->host; | |
1308 | if (S_ISBLK(inode->i_mode)) { | |
1309 | struct block_device *bdev = I_BDEV(inode); | |
1310 | set_blocksize(bdev, p->old_block_size); | |
1311 | bd_release(bdev); | |
1312 | } else { | |
1b1dcc1b | 1313 | mutex_lock(&inode->i_mutex); |
1da177e4 | 1314 | inode->i_flags &= ~S_SWAPFILE; |
1b1dcc1b | 1315 | mutex_unlock(&inode->i_mutex); |
1da177e4 LT |
1316 | } |
1317 | filp_close(swap_file, NULL); | |
1318 | err = 0; | |
1319 | ||
1320 | out_dput: | |
1321 | filp_close(victim, NULL); | |
1322 | out: | |
1323 | return err; | |
1324 | } | |
1325 | ||
1326 | #ifdef CONFIG_PROC_FS | |
1327 | /* iterator */ | |
1328 | static void *swap_start(struct seq_file *swap, loff_t *pos) | |
1329 | { | |
1330 | struct swap_info_struct *ptr = swap_info; | |
1331 | int i; | |
1332 | loff_t l = *pos; | |
1333 | ||
fc0abb14 | 1334 | mutex_lock(&swapon_mutex); |
1da177e4 | 1335 | |
881e4aab SS |
1336 | if (!l) |
1337 | return SEQ_START_TOKEN; | |
1338 | ||
1da177e4 LT |
1339 | for (i = 0; i < nr_swapfiles; i++, ptr++) { |
1340 | if (!(ptr->flags & SWP_USED) || !ptr->swap_map) | |
1341 | continue; | |
881e4aab | 1342 | if (!--l) |
1da177e4 LT |
1343 | return ptr; |
1344 | } | |
1345 | ||
1346 | return NULL; | |
1347 | } | |
1348 | ||
1349 | static void *swap_next(struct seq_file *swap, void *v, loff_t *pos) | |
1350 | { | |
881e4aab | 1351 | struct swap_info_struct *ptr; |
1da177e4 LT |
1352 | struct swap_info_struct *endptr = swap_info + nr_swapfiles; |
1353 | ||
881e4aab SS |
1354 | if (v == SEQ_START_TOKEN) |
1355 | ptr = swap_info; | |
1356 | else { | |
1357 | ptr = v; | |
1358 | ptr++; | |
1359 | } | |
1360 | ||
1361 | for (; ptr < endptr; ptr++) { | |
1da177e4 LT |
1362 | if (!(ptr->flags & SWP_USED) || !ptr->swap_map) |
1363 | continue; | |
1364 | ++*pos; | |
1365 | return ptr; | |
1366 | } | |
1367 | ||
1368 | return NULL; | |
1369 | } | |
1370 | ||
1371 | static void swap_stop(struct seq_file *swap, void *v) | |
1372 | { | |
fc0abb14 | 1373 | mutex_unlock(&swapon_mutex); |
1da177e4 LT |
1374 | } |
1375 | ||
1376 | static int swap_show(struct seq_file *swap, void *v) | |
1377 | { | |
1378 | struct swap_info_struct *ptr = v; | |
1379 | struct file *file; | |
1380 | int len; | |
1381 | ||
881e4aab SS |
1382 | if (ptr == SEQ_START_TOKEN) { |
1383 | seq_puts(swap,"Filename\t\t\t\tType\t\tSize\tUsed\tPriority\n"); | |
1384 | return 0; | |
1385 | } | |
1da177e4 LT |
1386 | |
1387 | file = ptr->swap_file; | |
d3ac7f89 | 1388 | len = seq_path(swap, file->f_path.mnt, file->f_path.dentry, " \t\n\\"); |
6eb396dc | 1389 | seq_printf(swap, "%*s%s\t%u\t%u\t%d\n", |
1da177e4 | 1390 | len < 40 ? 40 - len : 1, " ", |
d3ac7f89 | 1391 | S_ISBLK(file->f_path.dentry->d_inode->i_mode) ? |
1da177e4 LT |
1392 | "partition" : "file\t", |
1393 | ptr->pages << (PAGE_SHIFT - 10), | |
1394 | ptr->inuse_pages << (PAGE_SHIFT - 10), | |
1395 | ptr->prio); | |
1396 | return 0; | |
1397 | } | |
1398 | ||
15ad7cdc | 1399 | static const struct seq_operations swaps_op = { |
1da177e4 LT |
1400 | .start = swap_start, |
1401 | .next = swap_next, | |
1402 | .stop = swap_stop, | |
1403 | .show = swap_show | |
1404 | }; | |
1405 | ||
1406 | static int swaps_open(struct inode *inode, struct file *file) | |
1407 | { | |
1408 | return seq_open(file, &swaps_op); | |
1409 | } | |
1410 | ||
15ad7cdc | 1411 | static const struct file_operations proc_swaps_operations = { |
1da177e4 LT |
1412 | .open = swaps_open, |
1413 | .read = seq_read, | |
1414 | .llseek = seq_lseek, | |
1415 | .release = seq_release, | |
1416 | }; | |
1417 | ||
1418 | static int __init procswaps_init(void) | |
1419 | { | |
1420 | struct proc_dir_entry *entry; | |
1421 | ||
1422 | entry = create_proc_entry("swaps", 0, NULL); | |
1423 | if (entry) | |
1424 | entry->proc_fops = &proc_swaps_operations; | |
1425 | return 0; | |
1426 | } | |
1427 | __initcall(procswaps_init); | |
1428 | #endif /* CONFIG_PROC_FS */ | |
1429 | ||
1430 | /* | |
1431 | * Written 01/25/92 by Simmule Turner, heavily changed by Linus. | |
1432 | * | |
1433 | * The swapon system call | |
1434 | */ | |
1435 | asmlinkage long sys_swapon(const char __user * specialfile, int swap_flags) | |
1436 | { | |
1437 | struct swap_info_struct * p; | |
1438 | char *name = NULL; | |
1439 | struct block_device *bdev = NULL; | |
1440 | struct file *swap_file = NULL; | |
1441 | struct address_space *mapping; | |
1442 | unsigned int type; | |
1443 | int i, prev; | |
1444 | int error; | |
1445 | static int least_priority; | |
1446 | union swap_header *swap_header = NULL; | |
1447 | int swap_header_version; | |
6eb396dc HD |
1448 | unsigned int nr_good_pages = 0; |
1449 | int nr_extents = 0; | |
53092a74 | 1450 | sector_t span; |
1da177e4 LT |
1451 | unsigned long maxpages = 1; |
1452 | int swapfilesize; | |
1453 | unsigned short *swap_map; | |
1454 | struct page *page = NULL; | |
1455 | struct inode *inode = NULL; | |
1456 | int did_down = 0; | |
1457 | ||
1458 | if (!capable(CAP_SYS_ADMIN)) | |
1459 | return -EPERM; | |
5d337b91 | 1460 | spin_lock(&swap_lock); |
1da177e4 LT |
1461 | p = swap_info; |
1462 | for (type = 0 ; type < nr_swapfiles ; type++,p++) | |
1463 | if (!(p->flags & SWP_USED)) | |
1464 | break; | |
1465 | error = -EPERM; | |
0697212a | 1466 | if (type >= MAX_SWAPFILES) { |
5d337b91 | 1467 | spin_unlock(&swap_lock); |
1da177e4 LT |
1468 | goto out; |
1469 | } | |
1470 | if (type >= nr_swapfiles) | |
1471 | nr_swapfiles = type+1; | |
1472 | INIT_LIST_HEAD(&p->extent_list); | |
1473 | p->flags = SWP_USED; | |
1da177e4 LT |
1474 | p->swap_file = NULL; |
1475 | p->old_block_size = 0; | |
1476 | p->swap_map = NULL; | |
1477 | p->lowest_bit = 0; | |
1478 | p->highest_bit = 0; | |
1479 | p->cluster_nr = 0; | |
1480 | p->inuse_pages = 0; | |
1da177e4 LT |
1481 | p->next = -1; |
1482 | if (swap_flags & SWAP_FLAG_PREFER) { | |
1483 | p->prio = | |
1484 | (swap_flags & SWAP_FLAG_PRIO_MASK)>>SWAP_FLAG_PRIO_SHIFT; | |
1485 | } else { | |
1486 | p->prio = --least_priority; | |
1487 | } | |
5d337b91 | 1488 | spin_unlock(&swap_lock); |
1da177e4 LT |
1489 | name = getname(specialfile); |
1490 | error = PTR_ERR(name); | |
1491 | if (IS_ERR(name)) { | |
1492 | name = NULL; | |
1493 | goto bad_swap_2; | |
1494 | } | |
1495 | swap_file = filp_open(name, O_RDWR|O_LARGEFILE, 0); | |
1496 | error = PTR_ERR(swap_file); | |
1497 | if (IS_ERR(swap_file)) { | |
1498 | swap_file = NULL; | |
1499 | goto bad_swap_2; | |
1500 | } | |
1501 | ||
1502 | p->swap_file = swap_file; | |
1503 | mapping = swap_file->f_mapping; | |
1504 | inode = mapping->host; | |
1505 | ||
1506 | error = -EBUSY; | |
1507 | for (i = 0; i < nr_swapfiles; i++) { | |
1508 | struct swap_info_struct *q = &swap_info[i]; | |
1509 | ||
1510 | if (i == type || !q->swap_file) | |
1511 | continue; | |
1512 | if (mapping == q->swap_file->f_mapping) | |
1513 | goto bad_swap; | |
1514 | } | |
1515 | ||
1516 | error = -EINVAL; | |
1517 | if (S_ISBLK(inode->i_mode)) { | |
1518 | bdev = I_BDEV(inode); | |
1519 | error = bd_claim(bdev, sys_swapon); | |
1520 | if (error < 0) { | |
1521 | bdev = NULL; | |
f7b3a435 | 1522 | error = -EINVAL; |
1da177e4 LT |
1523 | goto bad_swap; |
1524 | } | |
1525 | p->old_block_size = block_size(bdev); | |
1526 | error = set_blocksize(bdev, PAGE_SIZE); | |
1527 | if (error < 0) | |
1528 | goto bad_swap; | |
1529 | p->bdev = bdev; | |
1530 | } else if (S_ISREG(inode->i_mode)) { | |
1531 | p->bdev = inode->i_sb->s_bdev; | |
1b1dcc1b | 1532 | mutex_lock(&inode->i_mutex); |
1da177e4 LT |
1533 | did_down = 1; |
1534 | if (IS_SWAPFILE(inode)) { | |
1535 | error = -EBUSY; | |
1536 | goto bad_swap; | |
1537 | } | |
1538 | } else { | |
1539 | goto bad_swap; | |
1540 | } | |
1541 | ||
1542 | swapfilesize = i_size_read(inode) >> PAGE_SHIFT; | |
1543 | ||
1544 | /* | |
1545 | * Read the swap header. | |
1546 | */ | |
1547 | if (!mapping->a_ops->readpage) { | |
1548 | error = -EINVAL; | |
1549 | goto bad_swap; | |
1550 | } | |
090d2b18 | 1551 | page = read_mapping_page(mapping, 0, swap_file); |
1da177e4 LT |
1552 | if (IS_ERR(page)) { |
1553 | error = PTR_ERR(page); | |
1554 | goto bad_swap; | |
1555 | } | |
1da177e4 LT |
1556 | kmap(page); |
1557 | swap_header = page_address(page); | |
1558 | ||
1559 | if (!memcmp("SWAP-SPACE",swap_header->magic.magic,10)) | |
1560 | swap_header_version = 1; | |
1561 | else if (!memcmp("SWAPSPACE2",swap_header->magic.magic,10)) | |
1562 | swap_header_version = 2; | |
1563 | else { | |
e97a3111 | 1564 | printk(KERN_ERR "Unable to find swap-space signature\n"); |
1da177e4 LT |
1565 | error = -EINVAL; |
1566 | goto bad_swap; | |
1567 | } | |
1568 | ||
1569 | switch (swap_header_version) { | |
1570 | case 1: | |
1571 | printk(KERN_ERR "version 0 swap is no longer supported. " | |
1572 | "Use mkswap -v1 %s\n", name); | |
1573 | error = -EINVAL; | |
1574 | goto bad_swap; | |
1575 | case 2: | |
1576 | /* Check the swap header's sub-version and the size of | |
1577 | the swap file and bad block lists */ | |
1578 | if (swap_header->info.version != 1) { | |
1579 | printk(KERN_WARNING | |
1580 | "Unable to handle swap header version %d\n", | |
1581 | swap_header->info.version); | |
1582 | error = -EINVAL; | |
1583 | goto bad_swap; | |
1584 | } | |
1585 | ||
1586 | p->lowest_bit = 1; | |
52b7efdb HD |
1587 | p->cluster_next = 1; |
1588 | ||
1da177e4 LT |
1589 | /* |
1590 | * Find out how many pages are allowed for a single swap | |
1591 | * device. There are two limiting factors: 1) the number of | |
1592 | * bits for the swap offset in the swp_entry_t type and | |
1593 | * 2) the number of bits in the a swap pte as defined by | |
1594 | * the different architectures. In order to find the | |
1595 | * largest possible bit mask a swap entry with swap type 0 | |
1596 | * and swap offset ~0UL is created, encoded to a swap pte, | |
1597 | * decoded to a swp_entry_t again and finally the swap | |
1598 | * offset is extracted. This will mask all the bits from | |
1599 | * the initial ~0UL mask that can't be encoded in either | |
1600 | * the swp_entry_t or the architecture definition of a | |
1601 | * swap pte. | |
1602 | */ | |
1603 | maxpages = swp_offset(pte_to_swp_entry(swp_entry_to_pte(swp_entry(0,~0UL)))) - 1; | |
1604 | if (maxpages > swap_header->info.last_page) | |
1605 | maxpages = swap_header->info.last_page; | |
1606 | p->highest_bit = maxpages - 1; | |
1607 | ||
1608 | error = -EINVAL; | |
e2244ec2 HD |
1609 | if (!maxpages) |
1610 | goto bad_swap; | |
5d1854e1 ES |
1611 | if (swapfilesize && maxpages > swapfilesize) { |
1612 | printk(KERN_WARNING | |
1613 | "Swap area shorter than signature indicates\n"); | |
1614 | goto bad_swap; | |
1615 | } | |
e2244ec2 HD |
1616 | if (swap_header->info.nr_badpages && S_ISREG(inode->i_mode)) |
1617 | goto bad_swap; | |
1da177e4 LT |
1618 | if (swap_header->info.nr_badpages > MAX_SWAP_BADPAGES) |
1619 | goto bad_swap; | |
cd105df4 | 1620 | |
1da177e4 LT |
1621 | /* OK, set up the swap map and apply the bad block list */ |
1622 | if (!(p->swap_map = vmalloc(maxpages * sizeof(short)))) { | |
1623 | error = -ENOMEM; | |
1624 | goto bad_swap; | |
1625 | } | |
1626 | ||
1627 | error = 0; | |
1628 | memset(p->swap_map, 0, maxpages * sizeof(short)); | |
cd105df4 TK |
1629 | for (i = 0; i < swap_header->info.nr_badpages; i++) { |
1630 | int page_nr = swap_header->info.badpages[i]; | |
1631 | if (page_nr <= 0 || page_nr >= swap_header->info.last_page) | |
1da177e4 LT |
1632 | error = -EINVAL; |
1633 | else | |
cd105df4 | 1634 | p->swap_map[page_nr] = SWAP_MAP_BAD; |
1da177e4 LT |
1635 | } |
1636 | nr_good_pages = swap_header->info.last_page - | |
1637 | swap_header->info.nr_badpages - | |
1638 | 1 /* header page */; | |
cd105df4 | 1639 | if (error) |
1da177e4 LT |
1640 | goto bad_swap; |
1641 | } | |
e2244ec2 | 1642 | |
e2244ec2 HD |
1643 | if (nr_good_pages) { |
1644 | p->swap_map[0] = SWAP_MAP_BAD; | |
1645 | p->max = maxpages; | |
1646 | p->pages = nr_good_pages; | |
53092a74 HD |
1647 | nr_extents = setup_swap_extents(p, &span); |
1648 | if (nr_extents < 0) { | |
1649 | error = nr_extents; | |
e2244ec2 | 1650 | goto bad_swap; |
53092a74 | 1651 | } |
e2244ec2 HD |
1652 | nr_good_pages = p->pages; |
1653 | } | |
1da177e4 LT |
1654 | if (!nr_good_pages) { |
1655 | printk(KERN_WARNING "Empty swap-file\n"); | |
1656 | error = -EINVAL; | |
1657 | goto bad_swap; | |
1658 | } | |
1da177e4 | 1659 | |
fc0abb14 | 1660 | mutex_lock(&swapon_mutex); |
5d337b91 | 1661 | spin_lock(&swap_lock); |
1da177e4 LT |
1662 | p->flags = SWP_ACTIVE; |
1663 | nr_swap_pages += nr_good_pages; | |
1664 | total_swap_pages += nr_good_pages; | |
53092a74 | 1665 | |
6eb396dc | 1666 | printk(KERN_INFO "Adding %uk swap on %s. " |
53092a74 HD |
1667 | "Priority:%d extents:%d across:%lluk\n", |
1668 | nr_good_pages<<(PAGE_SHIFT-10), name, p->prio, | |
1669 | nr_extents, (unsigned long long)span<<(PAGE_SHIFT-10)); | |
1da177e4 LT |
1670 | |
1671 | /* insert swap space into swap_list: */ | |
1672 | prev = -1; | |
1673 | for (i = swap_list.head; i >= 0; i = swap_info[i].next) { | |
1674 | if (p->prio >= swap_info[i].prio) { | |
1675 | break; | |
1676 | } | |
1677 | prev = i; | |
1678 | } | |
1679 | p->next = i; | |
1680 | if (prev < 0) { | |
1681 | swap_list.head = swap_list.next = p - swap_info; | |
1682 | } else { | |
1683 | swap_info[prev].next = p - swap_info; | |
1684 | } | |
5d337b91 | 1685 | spin_unlock(&swap_lock); |
fc0abb14 | 1686 | mutex_unlock(&swapon_mutex); |
1da177e4 LT |
1687 | error = 0; |
1688 | goto out; | |
1689 | bad_swap: | |
1690 | if (bdev) { | |
1691 | set_blocksize(bdev, p->old_block_size); | |
1692 | bd_release(bdev); | |
1693 | } | |
4cd3bb10 | 1694 | destroy_swap_extents(p); |
1da177e4 | 1695 | bad_swap_2: |
5d337b91 | 1696 | spin_lock(&swap_lock); |
1da177e4 LT |
1697 | swap_map = p->swap_map; |
1698 | p->swap_file = NULL; | |
1699 | p->swap_map = NULL; | |
1700 | p->flags = 0; | |
1701 | if (!(swap_flags & SWAP_FLAG_PREFER)) | |
1702 | ++least_priority; | |
5d337b91 | 1703 | spin_unlock(&swap_lock); |
1da177e4 LT |
1704 | vfree(swap_map); |
1705 | if (swap_file) | |
1706 | filp_close(swap_file, NULL); | |
1707 | out: | |
1708 | if (page && !IS_ERR(page)) { | |
1709 | kunmap(page); | |
1710 | page_cache_release(page); | |
1711 | } | |
1712 | if (name) | |
1713 | putname(name); | |
1714 | if (did_down) { | |
1715 | if (!error) | |
1716 | inode->i_flags |= S_SWAPFILE; | |
1b1dcc1b | 1717 | mutex_unlock(&inode->i_mutex); |
1da177e4 LT |
1718 | } |
1719 | return error; | |
1720 | } | |
1721 | ||
1722 | void si_swapinfo(struct sysinfo *val) | |
1723 | { | |
1724 | unsigned int i; | |
1725 | unsigned long nr_to_be_unused = 0; | |
1726 | ||
5d337b91 | 1727 | spin_lock(&swap_lock); |
1da177e4 LT |
1728 | for (i = 0; i < nr_swapfiles; i++) { |
1729 | if (!(swap_info[i].flags & SWP_USED) || | |
1730 | (swap_info[i].flags & SWP_WRITEOK)) | |
1731 | continue; | |
1732 | nr_to_be_unused += swap_info[i].inuse_pages; | |
1733 | } | |
1734 | val->freeswap = nr_swap_pages + nr_to_be_unused; | |
1735 | val->totalswap = total_swap_pages + nr_to_be_unused; | |
5d337b91 | 1736 | spin_unlock(&swap_lock); |
1da177e4 LT |
1737 | } |
1738 | ||
1739 | /* | |
1740 | * Verify that a swap entry is valid and increment its swap map count. | |
1741 | * | |
1742 | * Note: if swap_map[] reaches SWAP_MAP_MAX the entries are treated as | |
1743 | * "permanent", but will be reclaimed by the next swapoff. | |
1744 | */ | |
1745 | int swap_duplicate(swp_entry_t entry) | |
1746 | { | |
1747 | struct swap_info_struct * p; | |
1748 | unsigned long offset, type; | |
1749 | int result = 0; | |
1750 | ||
0697212a CL |
1751 | if (is_migration_entry(entry)) |
1752 | return 1; | |
1753 | ||
1da177e4 LT |
1754 | type = swp_type(entry); |
1755 | if (type >= nr_swapfiles) | |
1756 | goto bad_file; | |
1757 | p = type + swap_info; | |
1758 | offset = swp_offset(entry); | |
1759 | ||
5d337b91 | 1760 | spin_lock(&swap_lock); |
1da177e4 LT |
1761 | if (offset < p->max && p->swap_map[offset]) { |
1762 | if (p->swap_map[offset] < SWAP_MAP_MAX - 1) { | |
1763 | p->swap_map[offset]++; | |
1764 | result = 1; | |
1765 | } else if (p->swap_map[offset] <= SWAP_MAP_MAX) { | |
1766 | if (swap_overflow++ < 5) | |
1767 | printk(KERN_WARNING "swap_dup: swap entry overflow\n"); | |
1768 | p->swap_map[offset] = SWAP_MAP_MAX; | |
1769 | result = 1; | |
1770 | } | |
1771 | } | |
5d337b91 | 1772 | spin_unlock(&swap_lock); |
1da177e4 LT |
1773 | out: |
1774 | return result; | |
1775 | ||
1776 | bad_file: | |
1777 | printk(KERN_ERR "swap_dup: %s%08lx\n", Bad_file, entry.val); | |
1778 | goto out; | |
1779 | } | |
1780 | ||
1781 | struct swap_info_struct * | |
1782 | get_swap_info_struct(unsigned type) | |
1783 | { | |
1784 | return &swap_info[type]; | |
1785 | } | |
1786 | ||
1787 | /* | |
5d337b91 | 1788 | * swap_lock prevents swap_map being freed. Don't grab an extra |
1da177e4 LT |
1789 | * reference on the swaphandle, it doesn't matter if it becomes unused. |
1790 | */ | |
1791 | int valid_swaphandles(swp_entry_t entry, unsigned long *offset) | |
1792 | { | |
8952898b | 1793 | struct swap_info_struct *si; |
3f9e7949 | 1794 | int our_page_cluster = page_cluster; |
8952898b HD |
1795 | pgoff_t target, toff; |
1796 | pgoff_t base, end; | |
1797 | int nr_pages = 0; | |
1da177e4 | 1798 | |
3f9e7949 | 1799 | if (!our_page_cluster) /* no readahead */ |
1da177e4 | 1800 | return 0; |
8952898b HD |
1801 | |
1802 | si = &swap_info[swp_type(entry)]; | |
1803 | target = swp_offset(entry); | |
1804 | base = (target >> our_page_cluster) << our_page_cluster; | |
1805 | end = base + (1 << our_page_cluster); | |
1806 | if (!base) /* first page is swap header */ | |
1807 | base++; | |
1da177e4 | 1808 | |
5d337b91 | 1809 | spin_lock(&swap_lock); |
8952898b HD |
1810 | if (end > si->max) /* don't go beyond end of map */ |
1811 | end = si->max; | |
1812 | ||
1813 | /* Count contiguous allocated slots above our target */ | |
1814 | for (toff = target; ++toff < end; nr_pages++) { | |
1815 | /* Don't read in free or bad pages */ | |
1816 | if (!si->swap_map[toff]) | |
1817 | break; | |
1818 | if (si->swap_map[toff] == SWAP_MAP_BAD) | |
1da177e4 | 1819 | break; |
8952898b HD |
1820 | } |
1821 | /* Count contiguous allocated slots below our target */ | |
1822 | for (toff = target; --toff >= base; nr_pages++) { | |
1da177e4 | 1823 | /* Don't read in free or bad pages */ |
8952898b | 1824 | if (!si->swap_map[toff]) |
1da177e4 | 1825 | break; |
8952898b | 1826 | if (si->swap_map[toff] == SWAP_MAP_BAD) |
1da177e4 | 1827 | break; |
8952898b | 1828 | } |
5d337b91 | 1829 | spin_unlock(&swap_lock); |
8952898b HD |
1830 | |
1831 | /* | |
1832 | * Indicate starting offset, and return number of pages to get: | |
1833 | * if only 1, say 0, since there's then no readahead to be done. | |
1834 | */ | |
1835 | *offset = ++toff; | |
1836 | return nr_pages? ++nr_pages: 0; | |
1da177e4 | 1837 | } |