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 | ||
8 | #include <linux/config.h> | |
9 | #include <linux/mm.h> | |
10 | #include <linux/hugetlb.h> | |
11 | #include <linux/mman.h> | |
12 | #include <linux/slab.h> | |
13 | #include <linux/kernel_stat.h> | |
14 | #include <linux/swap.h> | |
15 | #include <linux/vmalloc.h> | |
16 | #include <linux/pagemap.h> | |
17 | #include <linux/namei.h> | |
18 | #include <linux/shm.h> | |
19 | #include <linux/blkdev.h> | |
20 | #include <linux/writeback.h> | |
21 | #include <linux/proc_fs.h> | |
22 | #include <linux/seq_file.h> | |
23 | #include <linux/init.h> | |
24 | #include <linux/module.h> | |
25 | #include <linux/rmap.h> | |
26 | #include <linux/security.h> | |
27 | #include <linux/backing-dev.h> | |
fc0abb14 | 28 | #include <linux/mutex.h> |
c59ede7b | 29 | #include <linux/capability.h> |
1da177e4 LT |
30 | #include <linux/syscalls.h> |
31 | ||
32 | #include <asm/pgtable.h> | |
33 | #include <asm/tlbflush.h> | |
34 | #include <linux/swapops.h> | |
35 | ||
5d337b91 | 36 | DEFINE_SPINLOCK(swap_lock); |
1da177e4 LT |
37 | unsigned int nr_swapfiles; |
38 | long total_swap_pages; | |
39 | static int swap_overflow; | |
40 | ||
1da177e4 LT |
41 | static const char Bad_file[] = "Bad swap file entry "; |
42 | static const char Unused_file[] = "Unused swap file entry "; | |
43 | static const char Bad_offset[] = "Bad swap offset entry "; | |
44 | static const char Unused_offset[] = "Unused swap offset entry "; | |
45 | ||
46 | struct swap_list_t swap_list = {-1, -1}; | |
47 | ||
f577eb30 | 48 | static struct swap_info_struct swap_info[MAX_SWAPFILES]; |
1da177e4 | 49 | |
fc0abb14 | 50 | static DEFINE_MUTEX(swapon_mutex); |
1da177e4 LT |
51 | |
52 | /* | |
53 | * We need this because the bdev->unplug_fn can sleep and we cannot | |
5d337b91 | 54 | * hold swap_lock while calling the unplug_fn. And swap_lock |
fc0abb14 | 55 | * cannot be turned into a mutex. |
1da177e4 LT |
56 | */ |
57 | static DECLARE_RWSEM(swap_unplug_sem); | |
58 | ||
1da177e4 LT |
59 | void swap_unplug_io_fn(struct backing_dev_info *unused_bdi, struct page *page) |
60 | { | |
61 | swp_entry_t entry; | |
62 | ||
63 | down_read(&swap_unplug_sem); | |
4c21e2f2 | 64 | entry.val = page_private(page); |
1da177e4 LT |
65 | if (PageSwapCache(page)) { |
66 | struct block_device *bdev = swap_info[swp_type(entry)].bdev; | |
67 | struct backing_dev_info *bdi; | |
68 | ||
69 | /* | |
70 | * If the page is removed from swapcache from under us (with a | |
71 | * racy try_to_unuse/swapoff) we need an additional reference | |
4c21e2f2 HD |
72 | * count to avoid reading garbage from page_private(page) above. |
73 | * If the WARN_ON triggers during a swapoff it maybe the race | |
1da177e4 LT |
74 | * condition and it's harmless. However if it triggers without |
75 | * swapoff it signals a problem. | |
76 | */ | |
77 | WARN_ON(page_count(page) <= 1); | |
78 | ||
79 | bdi = bdev->bd_inode->i_mapping->backing_dev_info; | |
ba32311e | 80 | blk_run_backing_dev(bdi, page); |
1da177e4 LT |
81 | } |
82 | up_read(&swap_unplug_sem); | |
83 | } | |
84 | ||
048c27fd HD |
85 | #define SWAPFILE_CLUSTER 256 |
86 | #define LATENCY_LIMIT 256 | |
87 | ||
6eb396dc | 88 | static inline unsigned long scan_swap_map(struct swap_info_struct *si) |
1da177e4 | 89 | { |
7dfad418 | 90 | unsigned long offset, last_in_cluster; |
048c27fd | 91 | int latency_ration = LATENCY_LIMIT; |
7dfad418 | 92 | |
1da177e4 | 93 | /* |
7dfad418 HD |
94 | * We try to cluster swap pages by allocating them sequentially |
95 | * in swap. Once we've allocated SWAPFILE_CLUSTER pages this | |
96 | * way, however, we resort to first-free allocation, starting | |
97 | * a new cluster. This prevents us from scattering swap pages | |
98 | * all over the entire swap partition, so that we reduce | |
99 | * overall disk seek times between swap pages. -- sct | |
100 | * But we do now try to find an empty cluster. -Andrea | |
101 | */ | |
102 | ||
52b7efdb | 103 | si->flags += SWP_SCANNING; |
7dfad418 HD |
104 | if (unlikely(!si->cluster_nr)) { |
105 | si->cluster_nr = SWAPFILE_CLUSTER - 1; | |
106 | if (si->pages - si->inuse_pages < SWAPFILE_CLUSTER) | |
107 | goto lowest; | |
5d337b91 | 108 | spin_unlock(&swap_lock); |
7dfad418 HD |
109 | |
110 | offset = si->lowest_bit; | |
111 | last_in_cluster = offset + SWAPFILE_CLUSTER - 1; | |
112 | ||
113 | /* Locate the first empty (unaligned) cluster */ | |
114 | for (; last_in_cluster <= si->highest_bit; offset++) { | |
1da177e4 | 115 | if (si->swap_map[offset]) |
7dfad418 HD |
116 | last_in_cluster = offset + SWAPFILE_CLUSTER; |
117 | else if (offset == last_in_cluster) { | |
5d337b91 | 118 | spin_lock(&swap_lock); |
9b65ef59 | 119 | si->cluster_next = offset-SWAPFILE_CLUSTER+1; |
7dfad418 | 120 | goto cluster; |
1da177e4 | 121 | } |
048c27fd HD |
122 | if (unlikely(--latency_ration < 0)) { |
123 | cond_resched(); | |
124 | latency_ration = LATENCY_LIMIT; | |
125 | } | |
7dfad418 | 126 | } |
5d337b91 | 127 | spin_lock(&swap_lock); |
7dfad418 | 128 | goto lowest; |
1da177e4 | 129 | } |
7dfad418 HD |
130 | |
131 | si->cluster_nr--; | |
132 | cluster: | |
133 | offset = si->cluster_next; | |
134 | if (offset > si->highest_bit) | |
135 | lowest: offset = si->lowest_bit; | |
52b7efdb HD |
136 | checks: if (!(si->flags & SWP_WRITEOK)) |
137 | goto no_page; | |
7dfad418 HD |
138 | if (!si->highest_bit) |
139 | goto no_page; | |
140 | if (!si->swap_map[offset]) { | |
52b7efdb | 141 | if (offset == si->lowest_bit) |
1da177e4 LT |
142 | si->lowest_bit++; |
143 | if (offset == si->highest_bit) | |
144 | si->highest_bit--; | |
7dfad418 HD |
145 | si->inuse_pages++; |
146 | if (si->inuse_pages == si->pages) { | |
1da177e4 LT |
147 | si->lowest_bit = si->max; |
148 | si->highest_bit = 0; | |
149 | } | |
150 | si->swap_map[offset] = 1; | |
7dfad418 | 151 | si->cluster_next = offset + 1; |
52b7efdb | 152 | si->flags -= SWP_SCANNING; |
1da177e4 LT |
153 | return offset; |
154 | } | |
7dfad418 | 155 | |
5d337b91 | 156 | spin_unlock(&swap_lock); |
7dfad418 | 157 | while (++offset <= si->highest_bit) { |
52b7efdb | 158 | if (!si->swap_map[offset]) { |
5d337b91 | 159 | spin_lock(&swap_lock); |
52b7efdb HD |
160 | goto checks; |
161 | } | |
048c27fd HD |
162 | if (unlikely(--latency_ration < 0)) { |
163 | cond_resched(); | |
164 | latency_ration = LATENCY_LIMIT; | |
165 | } | |
7dfad418 | 166 | } |
5d337b91 | 167 | spin_lock(&swap_lock); |
7dfad418 HD |
168 | goto lowest; |
169 | ||
170 | no_page: | |
52b7efdb | 171 | si->flags -= SWP_SCANNING; |
1da177e4 LT |
172 | return 0; |
173 | } | |
174 | ||
175 | swp_entry_t get_swap_page(void) | |
176 | { | |
fb4f88dc HD |
177 | struct swap_info_struct *si; |
178 | pgoff_t offset; | |
179 | int type, next; | |
180 | int wrapped = 0; | |
1da177e4 | 181 | |
5d337b91 | 182 | spin_lock(&swap_lock); |
1da177e4 | 183 | if (nr_swap_pages <= 0) |
fb4f88dc HD |
184 | goto noswap; |
185 | nr_swap_pages--; | |
186 | ||
187 | for (type = swap_list.next; type >= 0 && wrapped < 2; type = next) { | |
188 | si = swap_info + type; | |
189 | next = si->next; | |
190 | if (next < 0 || | |
191 | (!wrapped && si->prio != swap_info[next].prio)) { | |
192 | next = swap_list.head; | |
193 | wrapped++; | |
1da177e4 | 194 | } |
fb4f88dc HD |
195 | |
196 | if (!si->highest_bit) | |
197 | continue; | |
198 | if (!(si->flags & SWP_WRITEOK)) | |
199 | continue; | |
200 | ||
201 | swap_list.next = next; | |
fb4f88dc | 202 | offset = scan_swap_map(si); |
5d337b91 HD |
203 | if (offset) { |
204 | spin_unlock(&swap_lock); | |
fb4f88dc | 205 | return swp_entry(type, offset); |
5d337b91 | 206 | } |
fb4f88dc | 207 | next = swap_list.next; |
1da177e4 | 208 | } |
fb4f88dc HD |
209 | |
210 | nr_swap_pages++; | |
211 | noswap: | |
5d337b91 | 212 | spin_unlock(&swap_lock); |
fb4f88dc | 213 | return (swp_entry_t) {0}; |
1da177e4 LT |
214 | } |
215 | ||
3a291a20 RW |
216 | swp_entry_t get_swap_page_of_type(int type) |
217 | { | |
218 | struct swap_info_struct *si; | |
219 | pgoff_t offset; | |
220 | ||
221 | spin_lock(&swap_lock); | |
222 | si = swap_info + type; | |
223 | if (si->flags & SWP_WRITEOK) { | |
224 | nr_swap_pages--; | |
225 | offset = scan_swap_map(si); | |
226 | if (offset) { | |
227 | spin_unlock(&swap_lock); | |
228 | return swp_entry(type, offset); | |
229 | } | |
230 | nr_swap_pages++; | |
231 | } | |
232 | spin_unlock(&swap_lock); | |
233 | return (swp_entry_t) {0}; | |
234 | } | |
235 | ||
1da177e4 LT |
236 | static struct swap_info_struct * swap_info_get(swp_entry_t entry) |
237 | { | |
238 | struct swap_info_struct * p; | |
239 | unsigned long offset, type; | |
240 | ||
241 | if (!entry.val) | |
242 | goto out; | |
243 | type = swp_type(entry); | |
244 | if (type >= nr_swapfiles) | |
245 | goto bad_nofile; | |
246 | p = & swap_info[type]; | |
247 | if (!(p->flags & SWP_USED)) | |
248 | goto bad_device; | |
249 | offset = swp_offset(entry); | |
250 | if (offset >= p->max) | |
251 | goto bad_offset; | |
252 | if (!p->swap_map[offset]) | |
253 | goto bad_free; | |
5d337b91 | 254 | spin_lock(&swap_lock); |
1da177e4 LT |
255 | return p; |
256 | ||
257 | bad_free: | |
258 | printk(KERN_ERR "swap_free: %s%08lx\n", Unused_offset, entry.val); | |
259 | goto out; | |
260 | bad_offset: | |
261 | printk(KERN_ERR "swap_free: %s%08lx\n", Bad_offset, entry.val); | |
262 | goto out; | |
263 | bad_device: | |
264 | printk(KERN_ERR "swap_free: %s%08lx\n", Unused_file, entry.val); | |
265 | goto out; | |
266 | bad_nofile: | |
267 | printk(KERN_ERR "swap_free: %s%08lx\n", Bad_file, entry.val); | |
268 | out: | |
269 | return NULL; | |
270 | } | |
271 | ||
1da177e4 LT |
272 | static int swap_entry_free(struct swap_info_struct *p, unsigned long offset) |
273 | { | |
274 | int count = p->swap_map[offset]; | |
275 | ||
276 | if (count < SWAP_MAP_MAX) { | |
277 | count--; | |
278 | p->swap_map[offset] = count; | |
279 | if (!count) { | |
280 | if (offset < p->lowest_bit) | |
281 | p->lowest_bit = offset; | |
282 | if (offset > p->highest_bit) | |
283 | p->highest_bit = offset; | |
89d09a2c HD |
284 | if (p->prio > swap_info[swap_list.next].prio) |
285 | swap_list.next = p - swap_info; | |
1da177e4 LT |
286 | nr_swap_pages++; |
287 | p->inuse_pages--; | |
288 | } | |
289 | } | |
290 | return count; | |
291 | } | |
292 | ||
293 | /* | |
294 | * Caller has made sure that the swapdevice corresponding to entry | |
295 | * is still around or has not been recycled. | |
296 | */ | |
297 | void swap_free(swp_entry_t entry) | |
298 | { | |
299 | struct swap_info_struct * p; | |
300 | ||
301 | p = swap_info_get(entry); | |
302 | if (p) { | |
303 | swap_entry_free(p, swp_offset(entry)); | |
5d337b91 | 304 | spin_unlock(&swap_lock); |
1da177e4 LT |
305 | } |
306 | } | |
307 | ||
308 | /* | |
c475a8ab | 309 | * How many references to page are currently swapped out? |
1da177e4 | 310 | */ |
c475a8ab | 311 | static inline int page_swapcount(struct page *page) |
1da177e4 | 312 | { |
c475a8ab HD |
313 | int count = 0; |
314 | struct swap_info_struct *p; | |
1da177e4 LT |
315 | swp_entry_t entry; |
316 | ||
4c21e2f2 | 317 | entry.val = page_private(page); |
1da177e4 LT |
318 | p = swap_info_get(entry); |
319 | if (p) { | |
c475a8ab HD |
320 | /* Subtract the 1 for the swap cache itself */ |
321 | count = p->swap_map[swp_offset(entry)] - 1; | |
5d337b91 | 322 | spin_unlock(&swap_lock); |
1da177e4 | 323 | } |
c475a8ab | 324 | return count; |
1da177e4 LT |
325 | } |
326 | ||
327 | /* | |
328 | * We can use this swap cache entry directly | |
329 | * if there are no other references to it. | |
1da177e4 LT |
330 | */ |
331 | int can_share_swap_page(struct page *page) | |
332 | { | |
c475a8ab HD |
333 | int count; |
334 | ||
335 | BUG_ON(!PageLocked(page)); | |
336 | count = page_mapcount(page); | |
337 | if (count <= 1 && PageSwapCache(page)) | |
338 | count += page_swapcount(page); | |
339 | return count == 1; | |
1da177e4 LT |
340 | } |
341 | ||
342 | /* | |
343 | * Work out if there are any other processes sharing this | |
344 | * swap cache page. Free it if you can. Return success. | |
345 | */ | |
346 | int remove_exclusive_swap_page(struct page *page) | |
347 | { | |
348 | int retval; | |
349 | struct swap_info_struct * p; | |
350 | swp_entry_t entry; | |
351 | ||
352 | BUG_ON(PagePrivate(page)); | |
353 | BUG_ON(!PageLocked(page)); | |
354 | ||
355 | if (!PageSwapCache(page)) | |
356 | return 0; | |
357 | if (PageWriteback(page)) | |
358 | return 0; | |
359 | if (page_count(page) != 2) /* 2: us + cache */ | |
360 | return 0; | |
361 | ||
4c21e2f2 | 362 | entry.val = page_private(page); |
1da177e4 LT |
363 | p = swap_info_get(entry); |
364 | if (!p) | |
365 | return 0; | |
366 | ||
367 | /* Is the only swap cache user the cache itself? */ | |
368 | retval = 0; | |
369 | if (p->swap_map[swp_offset(entry)] == 1) { | |
370 | /* Recheck the page count with the swapcache lock held.. */ | |
371 | write_lock_irq(&swapper_space.tree_lock); | |
372 | if ((page_count(page) == 2) && !PageWriteback(page)) { | |
373 | __delete_from_swap_cache(page); | |
374 | SetPageDirty(page); | |
375 | retval = 1; | |
376 | } | |
377 | write_unlock_irq(&swapper_space.tree_lock); | |
378 | } | |
5d337b91 | 379 | spin_unlock(&swap_lock); |
1da177e4 LT |
380 | |
381 | if (retval) { | |
382 | swap_free(entry); | |
383 | page_cache_release(page); | |
384 | } | |
385 | ||
386 | return retval; | |
387 | } | |
388 | ||
389 | /* | |
390 | * Free the swap entry like above, but also try to | |
391 | * free the page cache entry if it is the last user. | |
392 | */ | |
393 | void free_swap_and_cache(swp_entry_t entry) | |
394 | { | |
395 | struct swap_info_struct * p; | |
396 | struct page *page = NULL; | |
397 | ||
0697212a CL |
398 | if (is_migration_entry(entry)) |
399 | return; | |
400 | ||
1da177e4 LT |
401 | p = swap_info_get(entry); |
402 | if (p) { | |
93fac704 NP |
403 | if (swap_entry_free(p, swp_offset(entry)) == 1) { |
404 | page = find_get_page(&swapper_space, entry.val); | |
405 | if (page && unlikely(TestSetPageLocked(page))) { | |
406 | page_cache_release(page); | |
407 | page = NULL; | |
408 | } | |
409 | } | |
5d337b91 | 410 | spin_unlock(&swap_lock); |
1da177e4 LT |
411 | } |
412 | if (page) { | |
413 | int one_user; | |
414 | ||
415 | BUG_ON(PagePrivate(page)); | |
1da177e4 LT |
416 | one_user = (page_count(page) == 2); |
417 | /* Only cache user (+us), or swap space full? Free it! */ | |
93fac704 NP |
418 | /* Also recheck PageSwapCache after page is locked (above) */ |
419 | if (PageSwapCache(page) && !PageWriteback(page) && | |
420 | (one_user || vm_swap_full())) { | |
1da177e4 LT |
421 | delete_from_swap_cache(page); |
422 | SetPageDirty(page); | |
423 | } | |
424 | unlock_page(page); | |
425 | page_cache_release(page); | |
426 | } | |
427 | } | |
428 | ||
f577eb30 RW |
429 | #ifdef CONFIG_SOFTWARE_SUSPEND |
430 | /* | |
431 | * Find the swap type that corresponds to given device (if any) | |
432 | * | |
433 | * This is needed for software suspend and is done in such a way that inode | |
434 | * aliasing is allowed. | |
435 | */ | |
436 | int swap_type_of(dev_t device) | |
437 | { | |
438 | int i; | |
439 | ||
f577eb30 RW |
440 | spin_lock(&swap_lock); |
441 | for (i = 0; i < nr_swapfiles; i++) { | |
442 | struct inode *inode; | |
443 | ||
444 | if (!(swap_info[i].flags & SWP_WRITEOK)) | |
445 | continue; | |
6e1819d6 RW |
446 | if (!device) { |
447 | spin_unlock(&swap_lock); | |
448 | return i; | |
449 | } | |
f577eb30 RW |
450 | inode = swap_info->swap_file->f_dentry->d_inode; |
451 | if (S_ISBLK(inode->i_mode) && | |
452 | device == MKDEV(imajor(inode), iminor(inode))) { | |
453 | spin_unlock(&swap_lock); | |
454 | return i; | |
455 | } | |
456 | } | |
457 | spin_unlock(&swap_lock); | |
458 | return -ENODEV; | |
459 | } | |
460 | ||
461 | /* | |
462 | * Return either the total number of swap pages of given type, or the number | |
463 | * of free pages of that type (depending on @free) | |
464 | * | |
465 | * This is needed for software suspend | |
466 | */ | |
467 | unsigned int count_swap_pages(int type, int free) | |
468 | { | |
469 | unsigned int n = 0; | |
470 | ||
471 | if (type < nr_swapfiles) { | |
472 | spin_lock(&swap_lock); | |
473 | if (swap_info[type].flags & SWP_WRITEOK) { | |
474 | n = swap_info[type].pages; | |
475 | if (free) | |
476 | n -= swap_info[type].inuse_pages; | |
477 | } | |
478 | spin_unlock(&swap_lock); | |
479 | } | |
480 | return n; | |
481 | } | |
482 | #endif | |
483 | ||
1da177e4 | 484 | /* |
72866f6f HD |
485 | * No need to decide whether this PTE shares the swap entry with others, |
486 | * just let do_wp_page work it out if a write is requested later - to | |
487 | * force COW, vm_page_prot omits write permission from any private vma. | |
1da177e4 LT |
488 | */ |
489 | static void unuse_pte(struct vm_area_struct *vma, pte_t *pte, | |
490 | unsigned long addr, swp_entry_t entry, struct page *page) | |
491 | { | |
4294621f | 492 | inc_mm_counter(vma->vm_mm, anon_rss); |
1da177e4 LT |
493 | get_page(page); |
494 | set_pte_at(vma->vm_mm, addr, pte, | |
495 | pte_mkold(mk_pte(page, vma->vm_page_prot))); | |
496 | page_add_anon_rmap(page, vma, addr); | |
497 | swap_free(entry); | |
498 | /* | |
499 | * Move the page to the active list so it is not | |
500 | * immediately swapped out again after swapon. | |
501 | */ | |
502 | activate_page(page); | |
503 | } | |
504 | ||
505 | static int unuse_pte_range(struct vm_area_struct *vma, pmd_t *pmd, | |
506 | unsigned long addr, unsigned long end, | |
507 | swp_entry_t entry, struct page *page) | |
508 | { | |
1da177e4 | 509 | pte_t swp_pte = swp_entry_to_pte(entry); |
705e87c0 HD |
510 | pte_t *pte; |
511 | spinlock_t *ptl; | |
512 | int found = 0; | |
1da177e4 | 513 | |
705e87c0 | 514 | pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl); |
1da177e4 LT |
515 | do { |
516 | /* | |
517 | * swapoff spends a _lot_ of time in this loop! | |
518 | * Test inline before going to call unuse_pte. | |
519 | */ | |
520 | if (unlikely(pte_same(*pte, swp_pte))) { | |
705e87c0 HD |
521 | unuse_pte(vma, pte++, addr, entry, page); |
522 | found = 1; | |
523 | break; | |
1da177e4 LT |
524 | } |
525 | } while (pte++, addr += PAGE_SIZE, addr != end); | |
705e87c0 HD |
526 | pte_unmap_unlock(pte - 1, ptl); |
527 | return found; | |
1da177e4 LT |
528 | } |
529 | ||
530 | static inline int unuse_pmd_range(struct vm_area_struct *vma, pud_t *pud, | |
531 | unsigned long addr, unsigned long end, | |
532 | swp_entry_t entry, struct page *page) | |
533 | { | |
534 | pmd_t *pmd; | |
535 | unsigned long next; | |
536 | ||
537 | pmd = pmd_offset(pud, addr); | |
538 | do { | |
539 | next = pmd_addr_end(addr, end); | |
540 | if (pmd_none_or_clear_bad(pmd)) | |
541 | continue; | |
542 | if (unuse_pte_range(vma, pmd, addr, next, entry, page)) | |
543 | return 1; | |
544 | } while (pmd++, addr = next, addr != end); | |
545 | return 0; | |
546 | } | |
547 | ||
548 | static inline int unuse_pud_range(struct vm_area_struct *vma, pgd_t *pgd, | |
549 | unsigned long addr, unsigned long end, | |
550 | swp_entry_t entry, struct page *page) | |
551 | { | |
552 | pud_t *pud; | |
553 | unsigned long next; | |
554 | ||
555 | pud = pud_offset(pgd, addr); | |
556 | do { | |
557 | next = pud_addr_end(addr, end); | |
558 | if (pud_none_or_clear_bad(pud)) | |
559 | continue; | |
560 | if (unuse_pmd_range(vma, pud, addr, next, entry, page)) | |
561 | return 1; | |
562 | } while (pud++, addr = next, addr != end); | |
563 | return 0; | |
564 | } | |
565 | ||
566 | static int unuse_vma(struct vm_area_struct *vma, | |
567 | swp_entry_t entry, struct page *page) | |
568 | { | |
569 | pgd_t *pgd; | |
570 | unsigned long addr, end, next; | |
571 | ||
572 | if (page->mapping) { | |
573 | addr = page_address_in_vma(page, vma); | |
574 | if (addr == -EFAULT) | |
575 | return 0; | |
576 | else | |
577 | end = addr + PAGE_SIZE; | |
578 | } else { | |
579 | addr = vma->vm_start; | |
580 | end = vma->vm_end; | |
581 | } | |
582 | ||
583 | pgd = pgd_offset(vma->vm_mm, addr); | |
584 | do { | |
585 | next = pgd_addr_end(addr, end); | |
586 | if (pgd_none_or_clear_bad(pgd)) | |
587 | continue; | |
588 | if (unuse_pud_range(vma, pgd, addr, next, entry, page)) | |
589 | return 1; | |
590 | } while (pgd++, addr = next, addr != end); | |
591 | return 0; | |
592 | } | |
593 | ||
594 | static int unuse_mm(struct mm_struct *mm, | |
595 | swp_entry_t entry, struct page *page) | |
596 | { | |
597 | struct vm_area_struct *vma; | |
598 | ||
599 | if (!down_read_trylock(&mm->mmap_sem)) { | |
600 | /* | |
c475a8ab HD |
601 | * Activate page so shrink_cache is unlikely to unmap its |
602 | * ptes while lock is dropped, so swapoff can make progress. | |
1da177e4 | 603 | */ |
c475a8ab | 604 | activate_page(page); |
1da177e4 LT |
605 | unlock_page(page); |
606 | down_read(&mm->mmap_sem); | |
607 | lock_page(page); | |
608 | } | |
1da177e4 LT |
609 | for (vma = mm->mmap; vma; vma = vma->vm_next) { |
610 | if (vma->anon_vma && unuse_vma(vma, entry, page)) | |
611 | break; | |
612 | } | |
1da177e4 LT |
613 | up_read(&mm->mmap_sem); |
614 | /* | |
615 | * Currently unuse_mm cannot fail, but leave error handling | |
616 | * at call sites for now, since we change it from time to time. | |
617 | */ | |
618 | return 0; | |
619 | } | |
620 | ||
a3351e52 CL |
621 | #ifdef CONFIG_MIGRATION |
622 | int remove_vma_swap(struct vm_area_struct *vma, struct page *page) | |
623 | { | |
624 | swp_entry_t entry = { .val = page_private(page) }; | |
625 | ||
626 | return unuse_vma(vma, entry, page); | |
627 | } | |
628 | #endif | |
629 | ||
1da177e4 LT |
630 | /* |
631 | * Scan swap_map from current position to next entry still in use. | |
632 | * Recycle to start on reaching the end, returning 0 when empty. | |
633 | */ | |
6eb396dc HD |
634 | static unsigned int find_next_to_unuse(struct swap_info_struct *si, |
635 | unsigned int prev) | |
1da177e4 | 636 | { |
6eb396dc HD |
637 | unsigned int max = si->max; |
638 | unsigned int i = prev; | |
1da177e4 LT |
639 | int count; |
640 | ||
641 | /* | |
5d337b91 | 642 | * No need for swap_lock here: we're just looking |
1da177e4 LT |
643 | * for whether an entry is in use, not modifying it; false |
644 | * hits are okay, and sys_swapoff() has already prevented new | |
5d337b91 | 645 | * allocations from this area (while holding swap_lock). |
1da177e4 LT |
646 | */ |
647 | for (;;) { | |
648 | if (++i >= max) { | |
649 | if (!prev) { | |
650 | i = 0; | |
651 | break; | |
652 | } | |
653 | /* | |
654 | * No entries in use at top of swap_map, | |
655 | * loop back to start and recheck there. | |
656 | */ | |
657 | max = prev + 1; | |
658 | prev = 0; | |
659 | i = 1; | |
660 | } | |
661 | count = si->swap_map[i]; | |
662 | if (count && count != SWAP_MAP_BAD) | |
663 | break; | |
664 | } | |
665 | return i; | |
666 | } | |
667 | ||
668 | /* | |
669 | * We completely avoid races by reading each swap page in advance, | |
670 | * and then search for the process using it. All the necessary | |
671 | * page table adjustments can then be made atomically. | |
672 | */ | |
673 | static int try_to_unuse(unsigned int type) | |
674 | { | |
675 | struct swap_info_struct * si = &swap_info[type]; | |
676 | struct mm_struct *start_mm; | |
677 | unsigned short *swap_map; | |
678 | unsigned short swcount; | |
679 | struct page *page; | |
680 | swp_entry_t entry; | |
6eb396dc | 681 | unsigned int i = 0; |
1da177e4 LT |
682 | int retval = 0; |
683 | int reset_overflow = 0; | |
684 | int shmem; | |
685 | ||
686 | /* | |
687 | * When searching mms for an entry, a good strategy is to | |
688 | * start at the first mm we freed the previous entry from | |
689 | * (though actually we don't notice whether we or coincidence | |
690 | * freed the entry). Initialize this start_mm with a hold. | |
691 | * | |
692 | * A simpler strategy would be to start at the last mm we | |
693 | * freed the previous entry from; but that would take less | |
694 | * advantage of mmlist ordering, which clusters forked mms | |
695 | * together, child after parent. If we race with dup_mmap(), we | |
696 | * prefer to resolve parent before child, lest we miss entries | |
697 | * duplicated after we scanned child: using last mm would invert | |
698 | * that. Though it's only a serious concern when an overflowed | |
699 | * swap count is reset from SWAP_MAP_MAX, preventing a rescan. | |
700 | */ | |
701 | start_mm = &init_mm; | |
702 | atomic_inc(&init_mm.mm_users); | |
703 | ||
704 | /* | |
705 | * Keep on scanning until all entries have gone. Usually, | |
706 | * one pass through swap_map is enough, but not necessarily: | |
707 | * there are races when an instance of an entry might be missed. | |
708 | */ | |
709 | while ((i = find_next_to_unuse(si, i)) != 0) { | |
710 | if (signal_pending(current)) { | |
711 | retval = -EINTR; | |
712 | break; | |
713 | } | |
714 | ||
715 | /* | |
716 | * Get a page for the entry, using the existing swap | |
717 | * cache page if there is one. Otherwise, get a clean | |
718 | * page and read the swap into it. | |
719 | */ | |
720 | swap_map = &si->swap_map[i]; | |
721 | entry = swp_entry(type, i); | |
722 | page = read_swap_cache_async(entry, NULL, 0); | |
723 | if (!page) { | |
724 | /* | |
725 | * Either swap_duplicate() failed because entry | |
726 | * has been freed independently, and will not be | |
727 | * reused since sys_swapoff() already disabled | |
728 | * allocation from here, or alloc_page() failed. | |
729 | */ | |
730 | if (!*swap_map) | |
731 | continue; | |
732 | retval = -ENOMEM; | |
733 | break; | |
734 | } | |
735 | ||
736 | /* | |
737 | * Don't hold on to start_mm if it looks like exiting. | |
738 | */ | |
739 | if (atomic_read(&start_mm->mm_users) == 1) { | |
740 | mmput(start_mm); | |
741 | start_mm = &init_mm; | |
742 | atomic_inc(&init_mm.mm_users); | |
743 | } | |
744 | ||
745 | /* | |
746 | * Wait for and lock page. When do_swap_page races with | |
747 | * try_to_unuse, do_swap_page can handle the fault much | |
748 | * faster than try_to_unuse can locate the entry. This | |
749 | * apparently redundant "wait_on_page_locked" lets try_to_unuse | |
750 | * defer to do_swap_page in such a case - in some tests, | |
751 | * do_swap_page and try_to_unuse repeatedly compete. | |
752 | */ | |
753 | wait_on_page_locked(page); | |
754 | wait_on_page_writeback(page); | |
755 | lock_page(page); | |
756 | wait_on_page_writeback(page); | |
757 | ||
758 | /* | |
759 | * Remove all references to entry. | |
760 | * Whenever we reach init_mm, there's no address space | |
761 | * to search, but use it as a reminder to search shmem. | |
762 | */ | |
763 | shmem = 0; | |
764 | swcount = *swap_map; | |
765 | if (swcount > 1) { | |
766 | if (start_mm == &init_mm) | |
767 | shmem = shmem_unuse(entry, page); | |
768 | else | |
769 | retval = unuse_mm(start_mm, entry, page); | |
770 | } | |
771 | if (*swap_map > 1) { | |
772 | int set_start_mm = (*swap_map >= swcount); | |
773 | struct list_head *p = &start_mm->mmlist; | |
774 | struct mm_struct *new_start_mm = start_mm; | |
775 | struct mm_struct *prev_mm = start_mm; | |
776 | struct mm_struct *mm; | |
777 | ||
778 | atomic_inc(&new_start_mm->mm_users); | |
779 | atomic_inc(&prev_mm->mm_users); | |
780 | spin_lock(&mmlist_lock); | |
781 | while (*swap_map > 1 && !retval && | |
782 | (p = p->next) != &start_mm->mmlist) { | |
783 | mm = list_entry(p, struct mm_struct, mmlist); | |
784 | if (atomic_inc_return(&mm->mm_users) == 1) { | |
785 | atomic_dec(&mm->mm_users); | |
786 | continue; | |
787 | } | |
788 | spin_unlock(&mmlist_lock); | |
789 | mmput(prev_mm); | |
790 | prev_mm = mm; | |
791 | ||
792 | cond_resched(); | |
793 | ||
794 | swcount = *swap_map; | |
795 | if (swcount <= 1) | |
796 | ; | |
797 | else if (mm == &init_mm) { | |
798 | set_start_mm = 1; | |
799 | shmem = shmem_unuse(entry, page); | |
800 | } else | |
801 | retval = unuse_mm(mm, entry, page); | |
802 | if (set_start_mm && *swap_map < swcount) { | |
803 | mmput(new_start_mm); | |
804 | atomic_inc(&mm->mm_users); | |
805 | new_start_mm = mm; | |
806 | set_start_mm = 0; | |
807 | } | |
808 | spin_lock(&mmlist_lock); | |
809 | } | |
810 | spin_unlock(&mmlist_lock); | |
811 | mmput(prev_mm); | |
812 | mmput(start_mm); | |
813 | start_mm = new_start_mm; | |
814 | } | |
815 | if (retval) { | |
816 | unlock_page(page); | |
817 | page_cache_release(page); | |
818 | break; | |
819 | } | |
820 | ||
821 | /* | |
822 | * How could swap count reach 0x7fff when the maximum | |
823 | * pid is 0x7fff, and there's no way to repeat a swap | |
824 | * page within an mm (except in shmem, where it's the | |
825 | * shared object which takes the reference count)? | |
826 | * We believe SWAP_MAP_MAX cannot occur in Linux 2.4. | |
827 | * | |
828 | * If that's wrong, then we should worry more about | |
829 | * exit_mmap() and do_munmap() cases described above: | |
830 | * we might be resetting SWAP_MAP_MAX too early here. | |
831 | * We know "Undead"s can happen, they're okay, so don't | |
832 | * report them; but do report if we reset SWAP_MAP_MAX. | |
833 | */ | |
834 | if (*swap_map == SWAP_MAP_MAX) { | |
5d337b91 | 835 | spin_lock(&swap_lock); |
1da177e4 | 836 | *swap_map = 1; |
5d337b91 | 837 | spin_unlock(&swap_lock); |
1da177e4 LT |
838 | reset_overflow = 1; |
839 | } | |
840 | ||
841 | /* | |
842 | * If a reference remains (rare), we would like to leave | |
843 | * the page in the swap cache; but try_to_unmap could | |
844 | * then re-duplicate the entry once we drop page lock, | |
845 | * so we might loop indefinitely; also, that page could | |
846 | * not be swapped out to other storage meanwhile. So: | |
847 | * delete from cache even if there's another reference, | |
848 | * after ensuring that the data has been saved to disk - | |
849 | * since if the reference remains (rarer), it will be | |
850 | * read from disk into another page. Splitting into two | |
851 | * pages would be incorrect if swap supported "shared | |
852 | * private" pages, but they are handled by tmpfs files. | |
853 | * | |
854 | * Note shmem_unuse already deleted a swappage from | |
855 | * the swap cache, unless the move to filepage failed: | |
856 | * in which case it left swappage in cache, lowered its | |
857 | * swap count to pass quickly through the loops above, | |
858 | * and now we must reincrement count to try again later. | |
859 | */ | |
860 | if ((*swap_map > 1) && PageDirty(page) && PageSwapCache(page)) { | |
861 | struct writeback_control wbc = { | |
862 | .sync_mode = WB_SYNC_NONE, | |
863 | }; | |
864 | ||
865 | swap_writepage(page, &wbc); | |
866 | lock_page(page); | |
867 | wait_on_page_writeback(page); | |
868 | } | |
869 | if (PageSwapCache(page)) { | |
870 | if (shmem) | |
871 | swap_duplicate(entry); | |
872 | else | |
873 | delete_from_swap_cache(page); | |
874 | } | |
875 | ||
876 | /* | |
877 | * So we could skip searching mms once swap count went | |
878 | * to 1, we did not mark any present ptes as dirty: must | |
879 | * mark page dirty so shrink_list will preserve it. | |
880 | */ | |
881 | SetPageDirty(page); | |
882 | unlock_page(page); | |
883 | page_cache_release(page); | |
884 | ||
885 | /* | |
886 | * Make sure that we aren't completely killing | |
887 | * interactive performance. | |
888 | */ | |
889 | cond_resched(); | |
890 | } | |
891 | ||
892 | mmput(start_mm); | |
893 | if (reset_overflow) { | |
894 | printk(KERN_WARNING "swapoff: cleared swap entry overflow\n"); | |
895 | swap_overflow = 0; | |
896 | } | |
897 | return retval; | |
898 | } | |
899 | ||
900 | /* | |
5d337b91 HD |
901 | * After a successful try_to_unuse, if no swap is now in use, we know |
902 | * we can empty the mmlist. swap_lock must be held on entry and exit. | |
903 | * Note that mmlist_lock nests inside swap_lock, and an mm must be | |
1da177e4 LT |
904 | * added to the mmlist just after page_duplicate - before would be racy. |
905 | */ | |
906 | static void drain_mmlist(void) | |
907 | { | |
908 | struct list_head *p, *next; | |
909 | unsigned int i; | |
910 | ||
911 | for (i = 0; i < nr_swapfiles; i++) | |
912 | if (swap_info[i].inuse_pages) | |
913 | return; | |
914 | spin_lock(&mmlist_lock); | |
915 | list_for_each_safe(p, next, &init_mm.mmlist) | |
916 | list_del_init(p); | |
917 | spin_unlock(&mmlist_lock); | |
918 | } | |
919 | ||
920 | /* | |
921 | * Use this swapdev's extent info to locate the (PAGE_SIZE) block which | |
922 | * corresponds to page offset `offset'. | |
923 | */ | |
924 | sector_t map_swap_page(struct swap_info_struct *sis, pgoff_t offset) | |
925 | { | |
926 | struct swap_extent *se = sis->curr_swap_extent; | |
927 | struct swap_extent *start_se = se; | |
928 | ||
929 | for ( ; ; ) { | |
930 | struct list_head *lh; | |
931 | ||
932 | if (se->start_page <= offset && | |
933 | offset < (se->start_page + se->nr_pages)) { | |
934 | return se->start_block + (offset - se->start_page); | |
935 | } | |
11d31886 | 936 | lh = se->list.next; |
1da177e4 | 937 | if (lh == &sis->extent_list) |
11d31886 | 938 | lh = lh->next; |
1da177e4 LT |
939 | se = list_entry(lh, struct swap_extent, list); |
940 | sis->curr_swap_extent = se; | |
941 | BUG_ON(se == start_se); /* It *must* be present */ | |
942 | } | |
943 | } | |
944 | ||
945 | /* | |
946 | * Free all of a swapdev's extent information | |
947 | */ | |
948 | static void destroy_swap_extents(struct swap_info_struct *sis) | |
949 | { | |
950 | while (!list_empty(&sis->extent_list)) { | |
951 | struct swap_extent *se; | |
952 | ||
953 | se = list_entry(sis->extent_list.next, | |
954 | struct swap_extent, list); | |
955 | list_del(&se->list); | |
956 | kfree(se); | |
957 | } | |
1da177e4 LT |
958 | } |
959 | ||
960 | /* | |
961 | * Add a block range (and the corresponding page range) into this swapdev's | |
11d31886 | 962 | * extent list. The extent list is kept sorted in page order. |
1da177e4 | 963 | * |
11d31886 | 964 | * This function rather assumes that it is called in ascending page order. |
1da177e4 LT |
965 | */ |
966 | static int | |
967 | add_swap_extent(struct swap_info_struct *sis, unsigned long start_page, | |
968 | unsigned long nr_pages, sector_t start_block) | |
969 | { | |
970 | struct swap_extent *se; | |
971 | struct swap_extent *new_se; | |
972 | struct list_head *lh; | |
973 | ||
11d31886 HD |
974 | lh = sis->extent_list.prev; /* The highest page extent */ |
975 | if (lh != &sis->extent_list) { | |
1da177e4 | 976 | se = list_entry(lh, struct swap_extent, list); |
11d31886 HD |
977 | BUG_ON(se->start_page + se->nr_pages != start_page); |
978 | if (se->start_block + se->nr_pages == start_block) { | |
1da177e4 LT |
979 | /* Merge it */ |
980 | se->nr_pages += nr_pages; | |
981 | return 0; | |
982 | } | |
1da177e4 LT |
983 | } |
984 | ||
985 | /* | |
986 | * No merge. Insert a new extent, preserving ordering. | |
987 | */ | |
988 | new_se = kmalloc(sizeof(*se), GFP_KERNEL); | |
989 | if (new_se == NULL) | |
990 | return -ENOMEM; | |
991 | new_se->start_page = start_page; | |
992 | new_se->nr_pages = nr_pages; | |
993 | new_se->start_block = start_block; | |
994 | ||
11d31886 | 995 | list_add_tail(&new_se->list, &sis->extent_list); |
53092a74 | 996 | return 1; |
1da177e4 LT |
997 | } |
998 | ||
999 | /* | |
1000 | * A `swap extent' is a simple thing which maps a contiguous range of pages | |
1001 | * onto a contiguous range of disk blocks. An ordered list of swap extents | |
1002 | * is built at swapon time and is then used at swap_writepage/swap_readpage | |
1003 | * time for locating where on disk a page belongs. | |
1004 | * | |
1005 | * If the swapfile is an S_ISBLK block device, a single extent is installed. | |
1006 | * This is done so that the main operating code can treat S_ISBLK and S_ISREG | |
1007 | * swap files identically. | |
1008 | * | |
1009 | * Whether the swapdev is an S_ISREG file or an S_ISBLK blockdev, the swap | |
1010 | * extent list operates in PAGE_SIZE disk blocks. Both S_ISREG and S_ISBLK | |
1011 | * swapfiles are handled *identically* after swapon time. | |
1012 | * | |
1013 | * For S_ISREG swapfiles, setup_swap_extents() will walk all the file's blocks | |
1014 | * and will parse them into an ordered extent list, in PAGE_SIZE chunks. If | |
1015 | * some stray blocks are found which do not fall within the PAGE_SIZE alignment | |
1016 | * requirements, they are simply tossed out - we will never use those blocks | |
1017 | * for swapping. | |
1018 | * | |
b0d9bcd4 | 1019 | * For S_ISREG swapfiles we set S_SWAPFILE across the life of the swapon. This |
1da177e4 LT |
1020 | * prevents root from shooting her foot off by ftruncating an in-use swapfile, |
1021 | * which will scribble on the fs. | |
1022 | * | |
1023 | * The amount of disk space which a single swap extent represents varies. | |
1024 | * Typically it is in the 1-4 megabyte range. So we can have hundreds of | |
1025 | * extents in the list. To avoid much list walking, we cache the previous | |
1026 | * search location in `curr_swap_extent', and start new searches from there. | |
1027 | * This is extremely effective. The average number of iterations in | |
1028 | * map_swap_page() has been measured at about 0.3 per page. - akpm. | |
1029 | */ | |
53092a74 | 1030 | static int setup_swap_extents(struct swap_info_struct *sis, sector_t *span) |
1da177e4 LT |
1031 | { |
1032 | struct inode *inode; | |
1033 | unsigned blocks_per_page; | |
1034 | unsigned long page_no; | |
1035 | unsigned blkbits; | |
1036 | sector_t probe_block; | |
1037 | sector_t last_block; | |
53092a74 HD |
1038 | sector_t lowest_block = -1; |
1039 | sector_t highest_block = 0; | |
1040 | int nr_extents = 0; | |
1da177e4 LT |
1041 | int ret; |
1042 | ||
1043 | inode = sis->swap_file->f_mapping->host; | |
1044 | if (S_ISBLK(inode->i_mode)) { | |
1045 | ret = add_swap_extent(sis, 0, sis->max, 0); | |
53092a74 | 1046 | *span = sis->pages; |
1da177e4 LT |
1047 | goto done; |
1048 | } | |
1049 | ||
1050 | blkbits = inode->i_blkbits; | |
1051 | blocks_per_page = PAGE_SIZE >> blkbits; | |
1052 | ||
1053 | /* | |
1054 | * Map all the blocks into the extent list. This code doesn't try | |
1055 | * to be very smart. | |
1056 | */ | |
1057 | probe_block = 0; | |
1058 | page_no = 0; | |
1059 | last_block = i_size_read(inode) >> blkbits; | |
1060 | while ((probe_block + blocks_per_page) <= last_block && | |
1061 | page_no < sis->max) { | |
1062 | unsigned block_in_page; | |
1063 | sector_t first_block; | |
1064 | ||
1065 | first_block = bmap(inode, probe_block); | |
1066 | if (first_block == 0) | |
1067 | goto bad_bmap; | |
1068 | ||
1069 | /* | |
1070 | * It must be PAGE_SIZE aligned on-disk | |
1071 | */ | |
1072 | if (first_block & (blocks_per_page - 1)) { | |
1073 | probe_block++; | |
1074 | goto reprobe; | |
1075 | } | |
1076 | ||
1077 | for (block_in_page = 1; block_in_page < blocks_per_page; | |
1078 | block_in_page++) { | |
1079 | sector_t block; | |
1080 | ||
1081 | block = bmap(inode, probe_block + block_in_page); | |
1082 | if (block == 0) | |
1083 | goto bad_bmap; | |
1084 | if (block != first_block + block_in_page) { | |
1085 | /* Discontiguity */ | |
1086 | probe_block++; | |
1087 | goto reprobe; | |
1088 | } | |
1089 | } | |
1090 | ||
53092a74 HD |
1091 | first_block >>= (PAGE_SHIFT - blkbits); |
1092 | if (page_no) { /* exclude the header page */ | |
1093 | if (first_block < lowest_block) | |
1094 | lowest_block = first_block; | |
1095 | if (first_block > highest_block) | |
1096 | highest_block = first_block; | |
1097 | } | |
1098 | ||
1da177e4 LT |
1099 | /* |
1100 | * We found a PAGE_SIZE-length, PAGE_SIZE-aligned run of blocks | |
1101 | */ | |
53092a74 HD |
1102 | ret = add_swap_extent(sis, page_no, 1, first_block); |
1103 | if (ret < 0) | |
1da177e4 | 1104 | goto out; |
53092a74 | 1105 | nr_extents += ret; |
1da177e4 LT |
1106 | page_no++; |
1107 | probe_block += blocks_per_page; | |
1108 | reprobe: | |
1109 | continue; | |
1110 | } | |
53092a74 HD |
1111 | ret = nr_extents; |
1112 | *span = 1 + highest_block - lowest_block; | |
1da177e4 | 1113 | if (page_no == 0) |
e2244ec2 | 1114 | page_no = 1; /* force Empty message */ |
1da177e4 | 1115 | sis->max = page_no; |
e2244ec2 | 1116 | sis->pages = page_no - 1; |
1da177e4 LT |
1117 | sis->highest_bit = page_no - 1; |
1118 | done: | |
1119 | sis->curr_swap_extent = list_entry(sis->extent_list.prev, | |
1120 | struct swap_extent, list); | |
1121 | goto out; | |
1122 | bad_bmap: | |
1123 | printk(KERN_ERR "swapon: swapfile has holes\n"); | |
1124 | ret = -EINVAL; | |
1125 | out: | |
1126 | return ret; | |
1127 | } | |
1128 | ||
1129 | #if 0 /* We don't need this yet */ | |
1130 | #include <linux/backing-dev.h> | |
1131 | int page_queue_congested(struct page *page) | |
1132 | { | |
1133 | struct backing_dev_info *bdi; | |
1134 | ||
1135 | BUG_ON(!PageLocked(page)); /* It pins the swap_info_struct */ | |
1136 | ||
1137 | if (PageSwapCache(page)) { | |
4c21e2f2 | 1138 | swp_entry_t entry = { .val = page_private(page) }; |
1da177e4 LT |
1139 | struct swap_info_struct *sis; |
1140 | ||
1141 | sis = get_swap_info_struct(swp_type(entry)); | |
1142 | bdi = sis->bdev->bd_inode->i_mapping->backing_dev_info; | |
1143 | } else | |
1144 | bdi = page->mapping->backing_dev_info; | |
1145 | return bdi_write_congested(bdi); | |
1146 | } | |
1147 | #endif | |
1148 | ||
1149 | asmlinkage long sys_swapoff(const char __user * specialfile) | |
1150 | { | |
1151 | struct swap_info_struct * p = NULL; | |
1152 | unsigned short *swap_map; | |
1153 | struct file *swap_file, *victim; | |
1154 | struct address_space *mapping; | |
1155 | struct inode *inode; | |
1156 | char * pathname; | |
1157 | int i, type, prev; | |
1158 | int err; | |
1159 | ||
1160 | if (!capable(CAP_SYS_ADMIN)) | |
1161 | return -EPERM; | |
1162 | ||
1163 | pathname = getname(specialfile); | |
1164 | err = PTR_ERR(pathname); | |
1165 | if (IS_ERR(pathname)) | |
1166 | goto out; | |
1167 | ||
1168 | victim = filp_open(pathname, O_RDWR|O_LARGEFILE, 0); | |
1169 | putname(pathname); | |
1170 | err = PTR_ERR(victim); | |
1171 | if (IS_ERR(victim)) | |
1172 | goto out; | |
1173 | ||
1174 | mapping = victim->f_mapping; | |
1175 | prev = -1; | |
5d337b91 | 1176 | spin_lock(&swap_lock); |
1da177e4 LT |
1177 | for (type = swap_list.head; type >= 0; type = swap_info[type].next) { |
1178 | p = swap_info + type; | |
1179 | if ((p->flags & SWP_ACTIVE) == SWP_ACTIVE) { | |
1180 | if (p->swap_file->f_mapping == mapping) | |
1181 | break; | |
1182 | } | |
1183 | prev = type; | |
1184 | } | |
1185 | if (type < 0) { | |
1186 | err = -EINVAL; | |
5d337b91 | 1187 | spin_unlock(&swap_lock); |
1da177e4 LT |
1188 | goto out_dput; |
1189 | } | |
1190 | if (!security_vm_enough_memory(p->pages)) | |
1191 | vm_unacct_memory(p->pages); | |
1192 | else { | |
1193 | err = -ENOMEM; | |
5d337b91 | 1194 | spin_unlock(&swap_lock); |
1da177e4 LT |
1195 | goto out_dput; |
1196 | } | |
1197 | if (prev < 0) { | |
1198 | swap_list.head = p->next; | |
1199 | } else { | |
1200 | swap_info[prev].next = p->next; | |
1201 | } | |
1202 | if (type == swap_list.next) { | |
1203 | /* just pick something that's safe... */ | |
1204 | swap_list.next = swap_list.head; | |
1205 | } | |
1206 | nr_swap_pages -= p->pages; | |
1207 | total_swap_pages -= p->pages; | |
1208 | p->flags &= ~SWP_WRITEOK; | |
5d337b91 | 1209 | spin_unlock(&swap_lock); |
fb4f88dc | 1210 | |
1da177e4 LT |
1211 | current->flags |= PF_SWAPOFF; |
1212 | err = try_to_unuse(type); | |
1213 | current->flags &= ~PF_SWAPOFF; | |
1214 | ||
1da177e4 LT |
1215 | if (err) { |
1216 | /* re-insert swap space back into swap_list */ | |
5d337b91 | 1217 | spin_lock(&swap_lock); |
1da177e4 LT |
1218 | for (prev = -1, i = swap_list.head; i >= 0; prev = i, i = swap_info[i].next) |
1219 | if (p->prio >= swap_info[i].prio) | |
1220 | break; | |
1221 | p->next = i; | |
1222 | if (prev < 0) | |
1223 | swap_list.head = swap_list.next = p - swap_info; | |
1224 | else | |
1225 | swap_info[prev].next = p - swap_info; | |
1226 | nr_swap_pages += p->pages; | |
1227 | total_swap_pages += p->pages; | |
1228 | p->flags |= SWP_WRITEOK; | |
5d337b91 | 1229 | spin_unlock(&swap_lock); |
1da177e4 LT |
1230 | goto out_dput; |
1231 | } | |
52b7efdb HD |
1232 | |
1233 | /* wait for any unplug function to finish */ | |
1234 | down_write(&swap_unplug_sem); | |
1235 | up_write(&swap_unplug_sem); | |
1236 | ||
5d337b91 | 1237 | destroy_swap_extents(p); |
fc0abb14 | 1238 | mutex_lock(&swapon_mutex); |
5d337b91 HD |
1239 | spin_lock(&swap_lock); |
1240 | drain_mmlist(); | |
1241 | ||
52b7efdb | 1242 | /* wait for anyone still in scan_swap_map */ |
52b7efdb HD |
1243 | p->highest_bit = 0; /* cuts scans short */ |
1244 | while (p->flags >= SWP_SCANNING) { | |
5d337b91 | 1245 | spin_unlock(&swap_lock); |
13e4b57f | 1246 | schedule_timeout_uninterruptible(1); |
5d337b91 | 1247 | spin_lock(&swap_lock); |
52b7efdb | 1248 | } |
52b7efdb | 1249 | |
1da177e4 LT |
1250 | swap_file = p->swap_file; |
1251 | p->swap_file = NULL; | |
1252 | p->max = 0; | |
1253 | swap_map = p->swap_map; | |
1254 | p->swap_map = NULL; | |
1255 | p->flags = 0; | |
5d337b91 | 1256 | spin_unlock(&swap_lock); |
fc0abb14 | 1257 | mutex_unlock(&swapon_mutex); |
1da177e4 LT |
1258 | vfree(swap_map); |
1259 | inode = mapping->host; | |
1260 | if (S_ISBLK(inode->i_mode)) { | |
1261 | struct block_device *bdev = I_BDEV(inode); | |
1262 | set_blocksize(bdev, p->old_block_size); | |
1263 | bd_release(bdev); | |
1264 | } else { | |
1b1dcc1b | 1265 | mutex_lock(&inode->i_mutex); |
1da177e4 | 1266 | inode->i_flags &= ~S_SWAPFILE; |
1b1dcc1b | 1267 | mutex_unlock(&inode->i_mutex); |
1da177e4 LT |
1268 | } |
1269 | filp_close(swap_file, NULL); | |
1270 | err = 0; | |
1271 | ||
1272 | out_dput: | |
1273 | filp_close(victim, NULL); | |
1274 | out: | |
1275 | return err; | |
1276 | } | |
1277 | ||
1278 | #ifdef CONFIG_PROC_FS | |
1279 | /* iterator */ | |
1280 | static void *swap_start(struct seq_file *swap, loff_t *pos) | |
1281 | { | |
1282 | struct swap_info_struct *ptr = swap_info; | |
1283 | int i; | |
1284 | loff_t l = *pos; | |
1285 | ||
fc0abb14 | 1286 | mutex_lock(&swapon_mutex); |
1da177e4 LT |
1287 | |
1288 | for (i = 0; i < nr_swapfiles; i++, ptr++) { | |
1289 | if (!(ptr->flags & SWP_USED) || !ptr->swap_map) | |
1290 | continue; | |
1291 | if (!l--) | |
1292 | return ptr; | |
1293 | } | |
1294 | ||
1295 | return NULL; | |
1296 | } | |
1297 | ||
1298 | static void *swap_next(struct seq_file *swap, void *v, loff_t *pos) | |
1299 | { | |
1300 | struct swap_info_struct *ptr = v; | |
1301 | struct swap_info_struct *endptr = swap_info + nr_swapfiles; | |
1302 | ||
1303 | for (++ptr; ptr < endptr; ptr++) { | |
1304 | if (!(ptr->flags & SWP_USED) || !ptr->swap_map) | |
1305 | continue; | |
1306 | ++*pos; | |
1307 | return ptr; | |
1308 | } | |
1309 | ||
1310 | return NULL; | |
1311 | } | |
1312 | ||
1313 | static void swap_stop(struct seq_file *swap, void *v) | |
1314 | { | |
fc0abb14 | 1315 | mutex_unlock(&swapon_mutex); |
1da177e4 LT |
1316 | } |
1317 | ||
1318 | static int swap_show(struct seq_file *swap, void *v) | |
1319 | { | |
1320 | struct swap_info_struct *ptr = v; | |
1321 | struct file *file; | |
1322 | int len; | |
1323 | ||
1324 | if (v == swap_info) | |
1325 | seq_puts(swap, "Filename\t\t\t\tType\t\tSize\tUsed\tPriority\n"); | |
1326 | ||
1327 | file = ptr->swap_file; | |
1328 | len = seq_path(swap, file->f_vfsmnt, file->f_dentry, " \t\n\\"); | |
6eb396dc | 1329 | seq_printf(swap, "%*s%s\t%u\t%u\t%d\n", |
1da177e4 LT |
1330 | len < 40 ? 40 - len : 1, " ", |
1331 | S_ISBLK(file->f_dentry->d_inode->i_mode) ? | |
1332 | "partition" : "file\t", | |
1333 | ptr->pages << (PAGE_SHIFT - 10), | |
1334 | ptr->inuse_pages << (PAGE_SHIFT - 10), | |
1335 | ptr->prio); | |
1336 | return 0; | |
1337 | } | |
1338 | ||
1339 | static struct seq_operations swaps_op = { | |
1340 | .start = swap_start, | |
1341 | .next = swap_next, | |
1342 | .stop = swap_stop, | |
1343 | .show = swap_show | |
1344 | }; | |
1345 | ||
1346 | static int swaps_open(struct inode *inode, struct file *file) | |
1347 | { | |
1348 | return seq_open(file, &swaps_op); | |
1349 | } | |
1350 | ||
1351 | static struct file_operations proc_swaps_operations = { | |
1352 | .open = swaps_open, | |
1353 | .read = seq_read, | |
1354 | .llseek = seq_lseek, | |
1355 | .release = seq_release, | |
1356 | }; | |
1357 | ||
1358 | static int __init procswaps_init(void) | |
1359 | { | |
1360 | struct proc_dir_entry *entry; | |
1361 | ||
1362 | entry = create_proc_entry("swaps", 0, NULL); | |
1363 | if (entry) | |
1364 | entry->proc_fops = &proc_swaps_operations; | |
1365 | return 0; | |
1366 | } | |
1367 | __initcall(procswaps_init); | |
1368 | #endif /* CONFIG_PROC_FS */ | |
1369 | ||
1370 | /* | |
1371 | * Written 01/25/92 by Simmule Turner, heavily changed by Linus. | |
1372 | * | |
1373 | * The swapon system call | |
1374 | */ | |
1375 | asmlinkage long sys_swapon(const char __user * specialfile, int swap_flags) | |
1376 | { | |
1377 | struct swap_info_struct * p; | |
1378 | char *name = NULL; | |
1379 | struct block_device *bdev = NULL; | |
1380 | struct file *swap_file = NULL; | |
1381 | struct address_space *mapping; | |
1382 | unsigned int type; | |
1383 | int i, prev; | |
1384 | int error; | |
1385 | static int least_priority; | |
1386 | union swap_header *swap_header = NULL; | |
1387 | int swap_header_version; | |
6eb396dc HD |
1388 | unsigned int nr_good_pages = 0; |
1389 | int nr_extents = 0; | |
53092a74 | 1390 | sector_t span; |
1da177e4 LT |
1391 | unsigned long maxpages = 1; |
1392 | int swapfilesize; | |
1393 | unsigned short *swap_map; | |
1394 | struct page *page = NULL; | |
1395 | struct inode *inode = NULL; | |
1396 | int did_down = 0; | |
1397 | ||
1398 | if (!capable(CAP_SYS_ADMIN)) | |
1399 | return -EPERM; | |
5d337b91 | 1400 | spin_lock(&swap_lock); |
1da177e4 LT |
1401 | p = swap_info; |
1402 | for (type = 0 ; type < nr_swapfiles ; type++,p++) | |
1403 | if (!(p->flags & SWP_USED)) | |
1404 | break; | |
1405 | error = -EPERM; | |
0697212a | 1406 | if (type >= MAX_SWAPFILES) { |
5d337b91 | 1407 | spin_unlock(&swap_lock); |
1da177e4 LT |
1408 | goto out; |
1409 | } | |
1410 | if (type >= nr_swapfiles) | |
1411 | nr_swapfiles = type+1; | |
1412 | INIT_LIST_HEAD(&p->extent_list); | |
1413 | p->flags = SWP_USED; | |
1da177e4 LT |
1414 | p->swap_file = NULL; |
1415 | p->old_block_size = 0; | |
1416 | p->swap_map = NULL; | |
1417 | p->lowest_bit = 0; | |
1418 | p->highest_bit = 0; | |
1419 | p->cluster_nr = 0; | |
1420 | p->inuse_pages = 0; | |
1da177e4 LT |
1421 | p->next = -1; |
1422 | if (swap_flags & SWAP_FLAG_PREFER) { | |
1423 | p->prio = | |
1424 | (swap_flags & SWAP_FLAG_PRIO_MASK)>>SWAP_FLAG_PRIO_SHIFT; | |
1425 | } else { | |
1426 | p->prio = --least_priority; | |
1427 | } | |
5d337b91 | 1428 | spin_unlock(&swap_lock); |
1da177e4 LT |
1429 | name = getname(specialfile); |
1430 | error = PTR_ERR(name); | |
1431 | if (IS_ERR(name)) { | |
1432 | name = NULL; | |
1433 | goto bad_swap_2; | |
1434 | } | |
1435 | swap_file = filp_open(name, O_RDWR|O_LARGEFILE, 0); | |
1436 | error = PTR_ERR(swap_file); | |
1437 | if (IS_ERR(swap_file)) { | |
1438 | swap_file = NULL; | |
1439 | goto bad_swap_2; | |
1440 | } | |
1441 | ||
1442 | p->swap_file = swap_file; | |
1443 | mapping = swap_file->f_mapping; | |
1444 | inode = mapping->host; | |
1445 | ||
1446 | error = -EBUSY; | |
1447 | for (i = 0; i < nr_swapfiles; i++) { | |
1448 | struct swap_info_struct *q = &swap_info[i]; | |
1449 | ||
1450 | if (i == type || !q->swap_file) | |
1451 | continue; | |
1452 | if (mapping == q->swap_file->f_mapping) | |
1453 | goto bad_swap; | |
1454 | } | |
1455 | ||
1456 | error = -EINVAL; | |
1457 | if (S_ISBLK(inode->i_mode)) { | |
1458 | bdev = I_BDEV(inode); | |
1459 | error = bd_claim(bdev, sys_swapon); | |
1460 | if (error < 0) { | |
1461 | bdev = NULL; | |
f7b3a435 | 1462 | error = -EINVAL; |
1da177e4 LT |
1463 | goto bad_swap; |
1464 | } | |
1465 | p->old_block_size = block_size(bdev); | |
1466 | error = set_blocksize(bdev, PAGE_SIZE); | |
1467 | if (error < 0) | |
1468 | goto bad_swap; | |
1469 | p->bdev = bdev; | |
1470 | } else if (S_ISREG(inode->i_mode)) { | |
1471 | p->bdev = inode->i_sb->s_bdev; | |
1b1dcc1b | 1472 | mutex_lock(&inode->i_mutex); |
1da177e4 LT |
1473 | did_down = 1; |
1474 | if (IS_SWAPFILE(inode)) { | |
1475 | error = -EBUSY; | |
1476 | goto bad_swap; | |
1477 | } | |
1478 | } else { | |
1479 | goto bad_swap; | |
1480 | } | |
1481 | ||
1482 | swapfilesize = i_size_read(inode) >> PAGE_SHIFT; | |
1483 | ||
1484 | /* | |
1485 | * Read the swap header. | |
1486 | */ | |
1487 | if (!mapping->a_ops->readpage) { | |
1488 | error = -EINVAL; | |
1489 | goto bad_swap; | |
1490 | } | |
1491 | page = read_cache_page(mapping, 0, | |
1492 | (filler_t *)mapping->a_ops->readpage, swap_file); | |
1493 | if (IS_ERR(page)) { | |
1494 | error = PTR_ERR(page); | |
1495 | goto bad_swap; | |
1496 | } | |
1497 | wait_on_page_locked(page); | |
1498 | if (!PageUptodate(page)) | |
1499 | goto bad_swap; | |
1500 | kmap(page); | |
1501 | swap_header = page_address(page); | |
1502 | ||
1503 | if (!memcmp("SWAP-SPACE",swap_header->magic.magic,10)) | |
1504 | swap_header_version = 1; | |
1505 | else if (!memcmp("SWAPSPACE2",swap_header->magic.magic,10)) | |
1506 | swap_header_version = 2; | |
1507 | else { | |
e97a3111 | 1508 | printk(KERN_ERR "Unable to find swap-space signature\n"); |
1da177e4 LT |
1509 | error = -EINVAL; |
1510 | goto bad_swap; | |
1511 | } | |
1512 | ||
1513 | switch (swap_header_version) { | |
1514 | case 1: | |
1515 | printk(KERN_ERR "version 0 swap is no longer supported. " | |
1516 | "Use mkswap -v1 %s\n", name); | |
1517 | error = -EINVAL; | |
1518 | goto bad_swap; | |
1519 | case 2: | |
1520 | /* Check the swap header's sub-version and the size of | |
1521 | the swap file and bad block lists */ | |
1522 | if (swap_header->info.version != 1) { | |
1523 | printk(KERN_WARNING | |
1524 | "Unable to handle swap header version %d\n", | |
1525 | swap_header->info.version); | |
1526 | error = -EINVAL; | |
1527 | goto bad_swap; | |
1528 | } | |
1529 | ||
1530 | p->lowest_bit = 1; | |
52b7efdb HD |
1531 | p->cluster_next = 1; |
1532 | ||
1da177e4 LT |
1533 | /* |
1534 | * Find out how many pages are allowed for a single swap | |
1535 | * device. There are two limiting factors: 1) the number of | |
1536 | * bits for the swap offset in the swp_entry_t type and | |
1537 | * 2) the number of bits in the a swap pte as defined by | |
1538 | * the different architectures. In order to find the | |
1539 | * largest possible bit mask a swap entry with swap type 0 | |
1540 | * and swap offset ~0UL is created, encoded to a swap pte, | |
1541 | * decoded to a swp_entry_t again and finally the swap | |
1542 | * offset is extracted. This will mask all the bits from | |
1543 | * the initial ~0UL mask that can't be encoded in either | |
1544 | * the swp_entry_t or the architecture definition of a | |
1545 | * swap pte. | |
1546 | */ | |
1547 | maxpages = swp_offset(pte_to_swp_entry(swp_entry_to_pte(swp_entry(0,~0UL)))) - 1; | |
1548 | if (maxpages > swap_header->info.last_page) | |
1549 | maxpages = swap_header->info.last_page; | |
1550 | p->highest_bit = maxpages - 1; | |
1551 | ||
1552 | error = -EINVAL; | |
e2244ec2 HD |
1553 | if (!maxpages) |
1554 | goto bad_swap; | |
1555 | if (swap_header->info.nr_badpages && S_ISREG(inode->i_mode)) | |
1556 | goto bad_swap; | |
1da177e4 LT |
1557 | if (swap_header->info.nr_badpages > MAX_SWAP_BADPAGES) |
1558 | goto bad_swap; | |
cd105df4 | 1559 | |
1da177e4 LT |
1560 | /* OK, set up the swap map and apply the bad block list */ |
1561 | if (!(p->swap_map = vmalloc(maxpages * sizeof(short)))) { | |
1562 | error = -ENOMEM; | |
1563 | goto bad_swap; | |
1564 | } | |
1565 | ||
1566 | error = 0; | |
1567 | memset(p->swap_map, 0, maxpages * sizeof(short)); | |
cd105df4 TK |
1568 | for (i = 0; i < swap_header->info.nr_badpages; i++) { |
1569 | int page_nr = swap_header->info.badpages[i]; | |
1570 | if (page_nr <= 0 || page_nr >= swap_header->info.last_page) | |
1da177e4 LT |
1571 | error = -EINVAL; |
1572 | else | |
cd105df4 | 1573 | p->swap_map[page_nr] = SWAP_MAP_BAD; |
1da177e4 LT |
1574 | } |
1575 | nr_good_pages = swap_header->info.last_page - | |
1576 | swap_header->info.nr_badpages - | |
1577 | 1 /* header page */; | |
cd105df4 | 1578 | if (error) |
1da177e4 LT |
1579 | goto bad_swap; |
1580 | } | |
e2244ec2 | 1581 | |
1da177e4 LT |
1582 | if (swapfilesize && maxpages > swapfilesize) { |
1583 | printk(KERN_WARNING | |
1584 | "Swap area shorter than signature indicates\n"); | |
1585 | error = -EINVAL; | |
1586 | goto bad_swap; | |
1587 | } | |
e2244ec2 HD |
1588 | if (nr_good_pages) { |
1589 | p->swap_map[0] = SWAP_MAP_BAD; | |
1590 | p->max = maxpages; | |
1591 | p->pages = nr_good_pages; | |
53092a74 HD |
1592 | nr_extents = setup_swap_extents(p, &span); |
1593 | if (nr_extents < 0) { | |
1594 | error = nr_extents; | |
e2244ec2 | 1595 | goto bad_swap; |
53092a74 | 1596 | } |
e2244ec2 HD |
1597 | nr_good_pages = p->pages; |
1598 | } | |
1da177e4 LT |
1599 | if (!nr_good_pages) { |
1600 | printk(KERN_WARNING "Empty swap-file\n"); | |
1601 | error = -EINVAL; | |
1602 | goto bad_swap; | |
1603 | } | |
1da177e4 | 1604 | |
fc0abb14 | 1605 | mutex_lock(&swapon_mutex); |
5d337b91 | 1606 | spin_lock(&swap_lock); |
1da177e4 LT |
1607 | p->flags = SWP_ACTIVE; |
1608 | nr_swap_pages += nr_good_pages; | |
1609 | total_swap_pages += nr_good_pages; | |
53092a74 | 1610 | |
6eb396dc | 1611 | printk(KERN_INFO "Adding %uk swap on %s. " |
53092a74 HD |
1612 | "Priority:%d extents:%d across:%lluk\n", |
1613 | nr_good_pages<<(PAGE_SHIFT-10), name, p->prio, | |
1614 | nr_extents, (unsigned long long)span<<(PAGE_SHIFT-10)); | |
1da177e4 LT |
1615 | |
1616 | /* insert swap space into swap_list: */ | |
1617 | prev = -1; | |
1618 | for (i = swap_list.head; i >= 0; i = swap_info[i].next) { | |
1619 | if (p->prio >= swap_info[i].prio) { | |
1620 | break; | |
1621 | } | |
1622 | prev = i; | |
1623 | } | |
1624 | p->next = i; | |
1625 | if (prev < 0) { | |
1626 | swap_list.head = swap_list.next = p - swap_info; | |
1627 | } else { | |
1628 | swap_info[prev].next = p - swap_info; | |
1629 | } | |
5d337b91 | 1630 | spin_unlock(&swap_lock); |
fc0abb14 | 1631 | mutex_unlock(&swapon_mutex); |
1da177e4 LT |
1632 | error = 0; |
1633 | goto out; | |
1634 | bad_swap: | |
1635 | if (bdev) { | |
1636 | set_blocksize(bdev, p->old_block_size); | |
1637 | bd_release(bdev); | |
1638 | } | |
4cd3bb10 | 1639 | destroy_swap_extents(p); |
1da177e4 | 1640 | bad_swap_2: |
5d337b91 | 1641 | spin_lock(&swap_lock); |
1da177e4 LT |
1642 | swap_map = p->swap_map; |
1643 | p->swap_file = NULL; | |
1644 | p->swap_map = NULL; | |
1645 | p->flags = 0; | |
1646 | if (!(swap_flags & SWAP_FLAG_PREFER)) | |
1647 | ++least_priority; | |
5d337b91 | 1648 | spin_unlock(&swap_lock); |
1da177e4 LT |
1649 | vfree(swap_map); |
1650 | if (swap_file) | |
1651 | filp_close(swap_file, NULL); | |
1652 | out: | |
1653 | if (page && !IS_ERR(page)) { | |
1654 | kunmap(page); | |
1655 | page_cache_release(page); | |
1656 | } | |
1657 | if (name) | |
1658 | putname(name); | |
1659 | if (did_down) { | |
1660 | if (!error) | |
1661 | inode->i_flags |= S_SWAPFILE; | |
1b1dcc1b | 1662 | mutex_unlock(&inode->i_mutex); |
1da177e4 LT |
1663 | } |
1664 | return error; | |
1665 | } | |
1666 | ||
1667 | void si_swapinfo(struct sysinfo *val) | |
1668 | { | |
1669 | unsigned int i; | |
1670 | unsigned long nr_to_be_unused = 0; | |
1671 | ||
5d337b91 | 1672 | spin_lock(&swap_lock); |
1da177e4 LT |
1673 | for (i = 0; i < nr_swapfiles; i++) { |
1674 | if (!(swap_info[i].flags & SWP_USED) || | |
1675 | (swap_info[i].flags & SWP_WRITEOK)) | |
1676 | continue; | |
1677 | nr_to_be_unused += swap_info[i].inuse_pages; | |
1678 | } | |
1679 | val->freeswap = nr_swap_pages + nr_to_be_unused; | |
1680 | val->totalswap = total_swap_pages + nr_to_be_unused; | |
5d337b91 | 1681 | spin_unlock(&swap_lock); |
1da177e4 LT |
1682 | } |
1683 | ||
1684 | /* | |
1685 | * Verify that a swap entry is valid and increment its swap map count. | |
1686 | * | |
1687 | * Note: if swap_map[] reaches SWAP_MAP_MAX the entries are treated as | |
1688 | * "permanent", but will be reclaimed by the next swapoff. | |
1689 | */ | |
1690 | int swap_duplicate(swp_entry_t entry) | |
1691 | { | |
1692 | struct swap_info_struct * p; | |
1693 | unsigned long offset, type; | |
1694 | int result = 0; | |
1695 | ||
0697212a CL |
1696 | if (is_migration_entry(entry)) |
1697 | return 1; | |
1698 | ||
1da177e4 LT |
1699 | type = swp_type(entry); |
1700 | if (type >= nr_swapfiles) | |
1701 | goto bad_file; | |
1702 | p = type + swap_info; | |
1703 | offset = swp_offset(entry); | |
1704 | ||
5d337b91 | 1705 | spin_lock(&swap_lock); |
1da177e4 LT |
1706 | if (offset < p->max && p->swap_map[offset]) { |
1707 | if (p->swap_map[offset] < SWAP_MAP_MAX - 1) { | |
1708 | p->swap_map[offset]++; | |
1709 | result = 1; | |
1710 | } else if (p->swap_map[offset] <= SWAP_MAP_MAX) { | |
1711 | if (swap_overflow++ < 5) | |
1712 | printk(KERN_WARNING "swap_dup: swap entry overflow\n"); | |
1713 | p->swap_map[offset] = SWAP_MAP_MAX; | |
1714 | result = 1; | |
1715 | } | |
1716 | } | |
5d337b91 | 1717 | spin_unlock(&swap_lock); |
1da177e4 LT |
1718 | out: |
1719 | return result; | |
1720 | ||
1721 | bad_file: | |
1722 | printk(KERN_ERR "swap_dup: %s%08lx\n", Bad_file, entry.val); | |
1723 | goto out; | |
1724 | } | |
1725 | ||
1726 | struct swap_info_struct * | |
1727 | get_swap_info_struct(unsigned type) | |
1728 | { | |
1729 | return &swap_info[type]; | |
1730 | } | |
1731 | ||
1732 | /* | |
5d337b91 | 1733 | * swap_lock prevents swap_map being freed. Don't grab an extra |
1da177e4 LT |
1734 | * reference on the swaphandle, it doesn't matter if it becomes unused. |
1735 | */ | |
1736 | int valid_swaphandles(swp_entry_t entry, unsigned long *offset) | |
1737 | { | |
1738 | int ret = 0, i = 1 << page_cluster; | |
1739 | unsigned long toff; | |
1740 | struct swap_info_struct *swapdev = swp_type(entry) + swap_info; | |
1741 | ||
1742 | if (!page_cluster) /* no readahead */ | |
1743 | return 0; | |
1744 | toff = (swp_offset(entry) >> page_cluster) << page_cluster; | |
1745 | if (!toff) /* first page is swap header */ | |
1746 | toff++, i--; | |
1747 | *offset = toff; | |
1748 | ||
5d337b91 | 1749 | spin_lock(&swap_lock); |
1da177e4 LT |
1750 | do { |
1751 | /* Don't read-ahead past the end of the swap area */ | |
1752 | if (toff >= swapdev->max) | |
1753 | break; | |
1754 | /* Don't read in free or bad pages */ | |
1755 | if (!swapdev->swap_map[toff]) | |
1756 | break; | |
1757 | if (swapdev->swap_map[toff] == SWAP_MAP_BAD) | |
1758 | break; | |
1759 | toff++; | |
1760 | ret++; | |
1761 | } while (--i); | |
5d337b91 | 1762 | spin_unlock(&swap_lock); |
1da177e4 LT |
1763 | return ret; |
1764 | } |