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b2441318 | 1 | // SPDX-License-Identifier: GPL-2.0 |
1da177e4 LT |
2 | /* |
3 | * linux/mm/madvise.c | |
4 | * | |
5 | * Copyright (C) 1999 Linus Torvalds | |
6 | * Copyright (C) 2002 Christoph Hellwig | |
7 | */ | |
8 | ||
9 | #include <linux/mman.h> | |
10 | #include <linux/pagemap.h> | |
11 | #include <linux/syscalls.h> | |
05b74384 | 12 | #include <linux/mempolicy.h> |
afcf938e | 13 | #include <linux/page-isolation.h> |
9c276cc6 | 14 | #include <linux/page_idle.h> |
05ce7724 | 15 | #include <linux/userfaultfd_k.h> |
1da177e4 | 16 | #include <linux/hugetlb.h> |
3f31d075 | 17 | #include <linux/falloc.h> |
692fe624 | 18 | #include <linux/fadvise.h> |
e8edc6e0 | 19 | #include <linux/sched.h> |
f8af4da3 | 20 | #include <linux/ksm.h> |
3f31d075 | 21 | #include <linux/fs.h> |
9ab4233d | 22 | #include <linux/file.h> |
1998cc04 | 23 | #include <linux/blkdev.h> |
66114cad | 24 | #include <linux/backing-dev.h> |
a520110e | 25 | #include <linux/pagewalk.h> |
1998cc04 SL |
26 | #include <linux/swap.h> |
27 | #include <linux/swapops.h> | |
3a4f8a0b | 28 | #include <linux/shmem_fs.h> |
854e9ed0 MK |
29 | #include <linux/mmu_notifier.h> |
30 | ||
31 | #include <asm/tlb.h> | |
1da177e4 | 32 | |
23519073 KS |
33 | #include "internal.h" |
34 | ||
d616d512 MK |
35 | struct madvise_walk_private { |
36 | struct mmu_gather *tlb; | |
37 | bool pageout; | |
38 | }; | |
39 | ||
0a27a14a NP |
40 | /* |
41 | * Any behaviour which results in changes to the vma->vm_flags needs to | |
42 | * take mmap_sem for writing. Others, which simply traverse vmas, need | |
43 | * to only take it for reading. | |
44 | */ | |
45 | static int madvise_need_mmap_write(int behavior) | |
46 | { | |
47 | switch (behavior) { | |
48 | case MADV_REMOVE: | |
49 | case MADV_WILLNEED: | |
50 | case MADV_DONTNEED: | |
9c276cc6 | 51 | case MADV_COLD: |
1a4e58cc | 52 | case MADV_PAGEOUT: |
854e9ed0 | 53 | case MADV_FREE: |
0a27a14a NP |
54 | return 0; |
55 | default: | |
56 | /* be safe, default to 1. list exceptions explicitly */ | |
57 | return 1; | |
58 | } | |
59 | } | |
60 | ||
1da177e4 LT |
61 | /* |
62 | * We can potentially split a vm area into separate | |
63 | * areas, each area with its own behavior. | |
64 | */ | |
ec9bed9d | 65 | static long madvise_behavior(struct vm_area_struct *vma, |
05b74384 PM |
66 | struct vm_area_struct **prev, |
67 | unsigned long start, unsigned long end, int behavior) | |
1da177e4 | 68 | { |
ec9bed9d | 69 | struct mm_struct *mm = vma->vm_mm; |
1da177e4 | 70 | int error = 0; |
05b74384 | 71 | pgoff_t pgoff; |
3866ea90 | 72 | unsigned long new_flags = vma->vm_flags; |
e798c6e8 PM |
73 | |
74 | switch (behavior) { | |
f8225661 MT |
75 | case MADV_NORMAL: |
76 | new_flags = new_flags & ~VM_RAND_READ & ~VM_SEQ_READ; | |
77 | break; | |
e798c6e8 | 78 | case MADV_SEQUENTIAL: |
f8225661 | 79 | new_flags = (new_flags & ~VM_RAND_READ) | VM_SEQ_READ; |
e798c6e8 PM |
80 | break; |
81 | case MADV_RANDOM: | |
f8225661 | 82 | new_flags = (new_flags & ~VM_SEQ_READ) | VM_RAND_READ; |
e798c6e8 | 83 | break; |
f8225661 MT |
84 | case MADV_DONTFORK: |
85 | new_flags |= VM_DONTCOPY; | |
86 | break; | |
87 | case MADV_DOFORK: | |
3866ea90 HD |
88 | if (vma->vm_flags & VM_IO) { |
89 | error = -EINVAL; | |
90 | goto out; | |
91 | } | |
f8225661 | 92 | new_flags &= ~VM_DONTCOPY; |
e798c6e8 | 93 | break; |
d2cd9ede RR |
94 | case MADV_WIPEONFORK: |
95 | /* MADV_WIPEONFORK is only supported on anonymous memory. */ | |
96 | if (vma->vm_file || vma->vm_flags & VM_SHARED) { | |
97 | error = -EINVAL; | |
98 | goto out; | |
99 | } | |
100 | new_flags |= VM_WIPEONFORK; | |
101 | break; | |
102 | case MADV_KEEPONFORK: | |
103 | new_flags &= ~VM_WIPEONFORK; | |
104 | break; | |
accb61fe | 105 | case MADV_DONTDUMP: |
0103bd16 | 106 | new_flags |= VM_DONTDUMP; |
accb61fe JB |
107 | break; |
108 | case MADV_DODUMP: | |
d41aa525 | 109 | if (!is_vm_hugetlb_page(vma) && new_flags & VM_SPECIAL) { |
0103bd16 KK |
110 | error = -EINVAL; |
111 | goto out; | |
112 | } | |
113 | new_flags &= ~VM_DONTDUMP; | |
accb61fe | 114 | break; |
f8af4da3 HD |
115 | case MADV_MERGEABLE: |
116 | case MADV_UNMERGEABLE: | |
117 | error = ksm_madvise(vma, start, end, behavior, &new_flags); | |
f3bc0dba MR |
118 | if (error) |
119 | goto out_convert_errno; | |
f8af4da3 | 120 | break; |
0af4e98b | 121 | case MADV_HUGEPAGE: |
a664b2d8 | 122 | case MADV_NOHUGEPAGE: |
60ab3244 | 123 | error = hugepage_madvise(vma, &new_flags, behavior); |
f3bc0dba MR |
124 | if (error) |
125 | goto out_convert_errno; | |
0af4e98b | 126 | break; |
e798c6e8 PM |
127 | } |
128 | ||
05b74384 PM |
129 | if (new_flags == vma->vm_flags) { |
130 | *prev = vma; | |
836d5ffd | 131 | goto out; |
05b74384 PM |
132 | } |
133 | ||
134 | pgoff = vma->vm_pgoff + ((start - vma->vm_start) >> PAGE_SHIFT); | |
135 | *prev = vma_merge(mm, *prev, start, end, new_flags, vma->anon_vma, | |
19a809af AA |
136 | vma->vm_file, pgoff, vma_policy(vma), |
137 | vma->vm_userfaultfd_ctx); | |
05b74384 PM |
138 | if (*prev) { |
139 | vma = *prev; | |
140 | goto success; | |
141 | } | |
142 | ||
143 | *prev = vma; | |
1da177e4 LT |
144 | |
145 | if (start != vma->vm_start) { | |
def5efe0 DR |
146 | if (unlikely(mm->map_count >= sysctl_max_map_count)) { |
147 | error = -ENOMEM; | |
1da177e4 | 148 | goto out; |
def5efe0 DR |
149 | } |
150 | error = __split_vma(mm, vma, start, 1); | |
f3bc0dba MR |
151 | if (error) |
152 | goto out_convert_errno; | |
1da177e4 LT |
153 | } |
154 | ||
155 | if (end != vma->vm_end) { | |
def5efe0 DR |
156 | if (unlikely(mm->map_count >= sysctl_max_map_count)) { |
157 | error = -ENOMEM; | |
1da177e4 | 158 | goto out; |
def5efe0 DR |
159 | } |
160 | error = __split_vma(mm, vma, end, 0); | |
f3bc0dba MR |
161 | if (error) |
162 | goto out_convert_errno; | |
1da177e4 LT |
163 | } |
164 | ||
836d5ffd | 165 | success: |
1da177e4 LT |
166 | /* |
167 | * vm_flags is protected by the mmap_sem held in write mode. | |
168 | */ | |
e798c6e8 | 169 | vma->vm_flags = new_flags; |
f3bc0dba MR |
170 | |
171 | out_convert_errno: | |
172 | /* | |
173 | * madvise() returns EAGAIN if kernel resources, such as | |
174 | * slab, are temporarily unavailable. | |
175 | */ | |
176 | if (error == -ENOMEM) | |
177 | error = -EAGAIN; | |
1da177e4 | 178 | out: |
1da177e4 LT |
179 | return error; |
180 | } | |
181 | ||
1998cc04 SL |
182 | #ifdef CONFIG_SWAP |
183 | static int swapin_walk_pmd_entry(pmd_t *pmd, unsigned long start, | |
184 | unsigned long end, struct mm_walk *walk) | |
185 | { | |
186 | pte_t *orig_pte; | |
187 | struct vm_area_struct *vma = walk->private; | |
188 | unsigned long index; | |
189 | ||
190 | if (pmd_none_or_trans_huge_or_clear_bad(pmd)) | |
191 | return 0; | |
192 | ||
193 | for (index = start; index != end; index += PAGE_SIZE) { | |
194 | pte_t pte; | |
195 | swp_entry_t entry; | |
196 | struct page *page; | |
197 | spinlock_t *ptl; | |
198 | ||
199 | orig_pte = pte_offset_map_lock(vma->vm_mm, pmd, start, &ptl); | |
200 | pte = *(orig_pte + ((index - start) / PAGE_SIZE)); | |
201 | pte_unmap_unlock(orig_pte, ptl); | |
202 | ||
0661a336 | 203 | if (pte_present(pte) || pte_none(pte)) |
1998cc04 SL |
204 | continue; |
205 | entry = pte_to_swp_entry(pte); | |
206 | if (unlikely(non_swap_entry(entry))) | |
207 | continue; | |
208 | ||
209 | page = read_swap_cache_async(entry, GFP_HIGHUSER_MOVABLE, | |
23955622 | 210 | vma, index, false); |
1998cc04 | 211 | if (page) |
09cbfeaf | 212 | put_page(page); |
1998cc04 SL |
213 | } |
214 | ||
215 | return 0; | |
216 | } | |
217 | ||
7b86ac33 CH |
218 | static const struct mm_walk_ops swapin_walk_ops = { |
219 | .pmd_entry = swapin_walk_pmd_entry, | |
220 | }; | |
1998cc04 SL |
221 | |
222 | static void force_shm_swapin_readahead(struct vm_area_struct *vma, | |
223 | unsigned long start, unsigned long end, | |
224 | struct address_space *mapping) | |
225 | { | |
226 | pgoff_t index; | |
227 | struct page *page; | |
228 | swp_entry_t swap; | |
229 | ||
230 | for (; start < end; start += PAGE_SIZE) { | |
231 | index = ((start - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff; | |
232 | ||
55231e5c | 233 | page = find_get_entry(mapping, index); |
3159f943 | 234 | if (!xa_is_value(page)) { |
1998cc04 | 235 | if (page) |
09cbfeaf | 236 | put_page(page); |
1998cc04 SL |
237 | continue; |
238 | } | |
239 | swap = radix_to_swp_entry(page); | |
240 | page = read_swap_cache_async(swap, GFP_HIGHUSER_MOVABLE, | |
23955622 | 241 | NULL, 0, false); |
1998cc04 | 242 | if (page) |
09cbfeaf | 243 | put_page(page); |
1998cc04 SL |
244 | } |
245 | ||
246 | lru_add_drain(); /* Push any new pages onto the LRU now */ | |
247 | } | |
248 | #endif /* CONFIG_SWAP */ | |
249 | ||
1da177e4 LT |
250 | /* |
251 | * Schedule all required I/O operations. Do not wait for completion. | |
252 | */ | |
ec9bed9d VC |
253 | static long madvise_willneed(struct vm_area_struct *vma, |
254 | struct vm_area_struct **prev, | |
1da177e4 LT |
255 | unsigned long start, unsigned long end) |
256 | { | |
257 | struct file *file = vma->vm_file; | |
692fe624 | 258 | loff_t offset; |
1da177e4 | 259 | |
6ea8d958 | 260 | *prev = vma; |
1998cc04 | 261 | #ifdef CONFIG_SWAP |
97b713ba | 262 | if (!file) { |
7b86ac33 CH |
263 | walk_page_range(vma->vm_mm, start, end, &swapin_walk_ops, vma); |
264 | lru_add_drain(); /* Push any new pages onto the LRU now */ | |
1998cc04 SL |
265 | return 0; |
266 | } | |
1998cc04 | 267 | |
97b713ba | 268 | if (shmem_mapping(file->f_mapping)) { |
97b713ba CH |
269 | force_shm_swapin_readahead(vma, start, end, |
270 | file->f_mapping); | |
271 | return 0; | |
272 | } | |
273 | #else | |
1bef4003 S |
274 | if (!file) |
275 | return -EBADF; | |
97b713ba | 276 | #endif |
1bef4003 | 277 | |
e748dcd0 | 278 | if (IS_DAX(file_inode(file))) { |
fe77ba6f CO |
279 | /* no bad return value, but ignore advice */ |
280 | return 0; | |
281 | } | |
282 | ||
692fe624 JK |
283 | /* |
284 | * Filesystem's fadvise may need to take various locks. We need to | |
285 | * explicitly grab a reference because the vma (and hence the | |
286 | * vma's reference to the file) can go away as soon as we drop | |
287 | * mmap_sem. | |
288 | */ | |
289 | *prev = NULL; /* tell sys_madvise we drop mmap_sem */ | |
290 | get_file(file); | |
291 | up_read(¤t->mm->mmap_sem); | |
292 | offset = (loff_t)(start - vma->vm_start) | |
293 | + ((loff_t)vma->vm_pgoff << PAGE_SHIFT); | |
294 | vfs_fadvise(file, offset, end - start, POSIX_FADV_WILLNEED); | |
295 | fput(file); | |
296 | down_read(¤t->mm->mmap_sem); | |
1da177e4 LT |
297 | return 0; |
298 | } | |
299 | ||
d616d512 MK |
300 | static int madvise_cold_or_pageout_pte_range(pmd_t *pmd, |
301 | unsigned long addr, unsigned long end, | |
302 | struct mm_walk *walk) | |
9c276cc6 | 303 | { |
d616d512 MK |
304 | struct madvise_walk_private *private = walk->private; |
305 | struct mmu_gather *tlb = private->tlb; | |
306 | bool pageout = private->pageout; | |
9c276cc6 MK |
307 | struct mm_struct *mm = tlb->mm; |
308 | struct vm_area_struct *vma = walk->vma; | |
309 | pte_t *orig_pte, *pte, ptent; | |
310 | spinlock_t *ptl; | |
d616d512 MK |
311 | struct page *page = NULL; |
312 | LIST_HEAD(page_list); | |
313 | ||
314 | if (fatal_signal_pending(current)) | |
315 | return -EINTR; | |
9c276cc6 MK |
316 | |
317 | #ifdef CONFIG_TRANSPARENT_HUGEPAGE | |
318 | if (pmd_trans_huge(*pmd)) { | |
319 | pmd_t orig_pmd; | |
320 | unsigned long next = pmd_addr_end(addr, end); | |
321 | ||
322 | tlb_change_page_size(tlb, HPAGE_PMD_SIZE); | |
323 | ptl = pmd_trans_huge_lock(pmd, vma); | |
324 | if (!ptl) | |
325 | return 0; | |
326 | ||
327 | orig_pmd = *pmd; | |
328 | if (is_huge_zero_pmd(orig_pmd)) | |
329 | goto huge_unlock; | |
330 | ||
331 | if (unlikely(!pmd_present(orig_pmd))) { | |
332 | VM_BUG_ON(thp_migration_supported() && | |
333 | !is_pmd_migration_entry(orig_pmd)); | |
334 | goto huge_unlock; | |
335 | } | |
336 | ||
337 | page = pmd_page(orig_pmd); | |
338 | if (next - addr != HPAGE_PMD_SIZE) { | |
339 | int err; | |
340 | ||
341 | if (page_mapcount(page) != 1) | |
342 | goto huge_unlock; | |
343 | ||
344 | get_page(page); | |
345 | spin_unlock(ptl); | |
346 | lock_page(page); | |
347 | err = split_huge_page(page); | |
348 | unlock_page(page); | |
349 | put_page(page); | |
350 | if (!err) | |
351 | goto regular_page; | |
352 | return 0; | |
353 | } | |
354 | ||
355 | if (pmd_young(orig_pmd)) { | |
356 | pmdp_invalidate(vma, addr, pmd); | |
357 | orig_pmd = pmd_mkold(orig_pmd); | |
358 | ||
359 | set_pmd_at(mm, addr, pmd, orig_pmd); | |
360 | tlb_remove_pmd_tlb_entry(tlb, pmd, addr); | |
361 | } | |
362 | ||
d616d512 | 363 | ClearPageReferenced(page); |
9c276cc6 | 364 | test_and_clear_page_young(page); |
d616d512 | 365 | if (pageout) { |
82072962 | 366 | if (!isolate_lru_page(page)) { |
367 | if (PageUnevictable(page)) | |
368 | putback_lru_page(page); | |
369 | else | |
370 | list_add(&page->lru, &page_list); | |
371 | } | |
d616d512 MK |
372 | } else |
373 | deactivate_page(page); | |
9c276cc6 MK |
374 | huge_unlock: |
375 | spin_unlock(ptl); | |
d616d512 MK |
376 | if (pageout) |
377 | reclaim_pages(&page_list); | |
9c276cc6 MK |
378 | return 0; |
379 | } | |
380 | ||
381 | if (pmd_trans_unstable(pmd)) | |
382 | return 0; | |
383 | regular_page: | |
384 | #endif | |
385 | tlb_change_page_size(tlb, PAGE_SIZE); | |
386 | orig_pte = pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl); | |
387 | flush_tlb_batched_pending(mm); | |
388 | arch_enter_lazy_mmu_mode(); | |
389 | for (; addr < end; pte++, addr += PAGE_SIZE) { | |
390 | ptent = *pte; | |
391 | ||
392 | if (pte_none(ptent)) | |
393 | continue; | |
394 | ||
395 | if (!pte_present(ptent)) | |
396 | continue; | |
397 | ||
398 | page = vm_normal_page(vma, addr, ptent); | |
399 | if (!page) | |
400 | continue; | |
401 | ||
402 | /* | |
403 | * Creating a THP page is expensive so split it only if we | |
404 | * are sure it's worth. Split it if we are only owner. | |
405 | */ | |
406 | if (PageTransCompound(page)) { | |
407 | if (page_mapcount(page) != 1) | |
408 | break; | |
409 | get_page(page); | |
410 | if (!trylock_page(page)) { | |
411 | put_page(page); | |
412 | break; | |
413 | } | |
414 | pte_unmap_unlock(orig_pte, ptl); | |
415 | if (split_huge_page(page)) { | |
416 | unlock_page(page); | |
417 | put_page(page); | |
418 | pte_offset_map_lock(mm, pmd, addr, &ptl); | |
419 | break; | |
420 | } | |
421 | unlock_page(page); | |
422 | put_page(page); | |
423 | pte = pte_offset_map_lock(mm, pmd, addr, &ptl); | |
424 | pte--; | |
425 | addr -= PAGE_SIZE; | |
426 | continue; | |
427 | } | |
428 | ||
429 | VM_BUG_ON_PAGE(PageTransCompound(page), page); | |
430 | ||
431 | if (pte_young(ptent)) { | |
432 | ptent = ptep_get_and_clear_full(mm, addr, pte, | |
433 | tlb->fullmm); | |
434 | ptent = pte_mkold(ptent); | |
435 | set_pte_at(mm, addr, pte, ptent); | |
436 | tlb_remove_tlb_entry(tlb, pte, addr); | |
437 | } | |
438 | ||
439 | /* | |
440 | * We are deactivating a page for accelerating reclaiming. | |
441 | * VM couldn't reclaim the page unless we clear PG_young. | |
442 | * As a side effect, it makes confuse idle-page tracking | |
443 | * because they will miss recent referenced history. | |
444 | */ | |
d616d512 | 445 | ClearPageReferenced(page); |
9c276cc6 | 446 | test_and_clear_page_young(page); |
d616d512 | 447 | if (pageout) { |
82072962 | 448 | if (!isolate_lru_page(page)) { |
449 | if (PageUnevictable(page)) | |
450 | putback_lru_page(page); | |
451 | else | |
452 | list_add(&page->lru, &page_list); | |
453 | } | |
d616d512 MK |
454 | } else |
455 | deactivate_page(page); | |
9c276cc6 MK |
456 | } |
457 | ||
458 | arch_leave_lazy_mmu_mode(); | |
459 | pte_unmap_unlock(orig_pte, ptl); | |
d616d512 MK |
460 | if (pageout) |
461 | reclaim_pages(&page_list); | |
9c276cc6 MK |
462 | cond_resched(); |
463 | ||
464 | return 0; | |
465 | } | |
466 | ||
467 | static const struct mm_walk_ops cold_walk_ops = { | |
d616d512 | 468 | .pmd_entry = madvise_cold_or_pageout_pte_range, |
9c276cc6 MK |
469 | }; |
470 | ||
471 | static void madvise_cold_page_range(struct mmu_gather *tlb, | |
472 | struct vm_area_struct *vma, | |
473 | unsigned long addr, unsigned long end) | |
474 | { | |
d616d512 MK |
475 | struct madvise_walk_private walk_private = { |
476 | .pageout = false, | |
477 | .tlb = tlb, | |
478 | }; | |
479 | ||
9c276cc6 | 480 | tlb_start_vma(tlb, vma); |
d616d512 | 481 | walk_page_range(vma->vm_mm, addr, end, &cold_walk_ops, &walk_private); |
9c276cc6 MK |
482 | tlb_end_vma(tlb, vma); |
483 | } | |
484 | ||
485 | static long madvise_cold(struct vm_area_struct *vma, | |
486 | struct vm_area_struct **prev, | |
487 | unsigned long start_addr, unsigned long end_addr) | |
488 | { | |
489 | struct mm_struct *mm = vma->vm_mm; | |
490 | struct mmu_gather tlb; | |
491 | ||
492 | *prev = vma; | |
493 | if (!can_madv_lru_vma(vma)) | |
494 | return -EINVAL; | |
495 | ||
496 | lru_add_drain(); | |
497 | tlb_gather_mmu(&tlb, mm, start_addr, end_addr); | |
498 | madvise_cold_page_range(&tlb, vma, start_addr, end_addr); | |
499 | tlb_finish_mmu(&tlb, start_addr, end_addr); | |
500 | ||
501 | return 0; | |
502 | } | |
503 | ||
1a4e58cc MK |
504 | static void madvise_pageout_page_range(struct mmu_gather *tlb, |
505 | struct vm_area_struct *vma, | |
506 | unsigned long addr, unsigned long end) | |
507 | { | |
d616d512 MK |
508 | struct madvise_walk_private walk_private = { |
509 | .pageout = true, | |
510 | .tlb = tlb, | |
511 | }; | |
512 | ||
1a4e58cc | 513 | tlb_start_vma(tlb, vma); |
d616d512 | 514 | walk_page_range(vma->vm_mm, addr, end, &cold_walk_ops, &walk_private); |
1a4e58cc MK |
515 | tlb_end_vma(tlb, vma); |
516 | } | |
517 | ||
518 | static inline bool can_do_pageout(struct vm_area_struct *vma) | |
519 | { | |
520 | if (vma_is_anonymous(vma)) | |
521 | return true; | |
522 | if (!vma->vm_file) | |
523 | return false; | |
524 | /* | |
525 | * paging out pagecache only for non-anonymous mappings that correspond | |
526 | * to the files the calling process could (if tried) open for writing; | |
527 | * otherwise we'd be including shared non-exclusive mappings, which | |
528 | * opens a side channel. | |
529 | */ | |
530 | return inode_owner_or_capable(file_inode(vma->vm_file)) || | |
531 | inode_permission(file_inode(vma->vm_file), MAY_WRITE) == 0; | |
532 | } | |
533 | ||
534 | static long madvise_pageout(struct vm_area_struct *vma, | |
535 | struct vm_area_struct **prev, | |
536 | unsigned long start_addr, unsigned long end_addr) | |
537 | { | |
538 | struct mm_struct *mm = vma->vm_mm; | |
539 | struct mmu_gather tlb; | |
540 | ||
541 | *prev = vma; | |
542 | if (!can_madv_lru_vma(vma)) | |
543 | return -EINVAL; | |
544 | ||
545 | if (!can_do_pageout(vma)) | |
546 | return 0; | |
547 | ||
548 | lru_add_drain(); | |
549 | tlb_gather_mmu(&tlb, mm, start_addr, end_addr); | |
550 | madvise_pageout_page_range(&tlb, vma, start_addr, end_addr); | |
551 | tlb_finish_mmu(&tlb, start_addr, end_addr); | |
552 | ||
553 | return 0; | |
554 | } | |
555 | ||
854e9ed0 MK |
556 | static int madvise_free_pte_range(pmd_t *pmd, unsigned long addr, |
557 | unsigned long end, struct mm_walk *walk) | |
558 | ||
559 | { | |
560 | struct mmu_gather *tlb = walk->private; | |
561 | struct mm_struct *mm = tlb->mm; | |
562 | struct vm_area_struct *vma = walk->vma; | |
563 | spinlock_t *ptl; | |
564 | pte_t *orig_pte, *pte, ptent; | |
565 | struct page *page; | |
64b42bc1 | 566 | int nr_swap = 0; |
b8d3c4c3 MK |
567 | unsigned long next; |
568 | ||
569 | next = pmd_addr_end(addr, end); | |
570 | if (pmd_trans_huge(*pmd)) | |
571 | if (madvise_free_huge_pmd(tlb, vma, pmd, addr, next)) | |
572 | goto next; | |
854e9ed0 | 573 | |
854e9ed0 MK |
574 | if (pmd_trans_unstable(pmd)) |
575 | return 0; | |
576 | ||
ed6a7935 | 577 | tlb_change_page_size(tlb, PAGE_SIZE); |
854e9ed0 | 578 | orig_pte = pte = pte_offset_map_lock(mm, pmd, addr, &ptl); |
3ea27719 | 579 | flush_tlb_batched_pending(mm); |
854e9ed0 MK |
580 | arch_enter_lazy_mmu_mode(); |
581 | for (; addr != end; pte++, addr += PAGE_SIZE) { | |
582 | ptent = *pte; | |
583 | ||
64b42bc1 | 584 | if (pte_none(ptent)) |
854e9ed0 | 585 | continue; |
64b42bc1 MK |
586 | /* |
587 | * If the pte has swp_entry, just clear page table to | |
588 | * prevent swap-in which is more expensive rather than | |
589 | * (page allocation + zeroing). | |
590 | */ | |
591 | if (!pte_present(ptent)) { | |
592 | swp_entry_t entry; | |
593 | ||
594 | entry = pte_to_swp_entry(ptent); | |
595 | if (non_swap_entry(entry)) | |
596 | continue; | |
597 | nr_swap--; | |
598 | free_swap_and_cache(entry); | |
599 | pte_clear_not_present_full(mm, addr, pte, tlb->fullmm); | |
600 | continue; | |
601 | } | |
854e9ed0 | 602 | |
25b2995a | 603 | page = vm_normal_page(vma, addr, ptent); |
854e9ed0 MK |
604 | if (!page) |
605 | continue; | |
606 | ||
607 | /* | |
608 | * If pmd isn't transhuge but the page is THP and | |
609 | * is owned by only this process, split it and | |
610 | * deactivate all pages. | |
611 | */ | |
612 | if (PageTransCompound(page)) { | |
613 | if (page_mapcount(page) != 1) | |
614 | goto out; | |
615 | get_page(page); | |
616 | if (!trylock_page(page)) { | |
617 | put_page(page); | |
618 | goto out; | |
619 | } | |
620 | pte_unmap_unlock(orig_pte, ptl); | |
621 | if (split_huge_page(page)) { | |
622 | unlock_page(page); | |
623 | put_page(page); | |
624 | pte_offset_map_lock(mm, pmd, addr, &ptl); | |
625 | goto out; | |
626 | } | |
854e9ed0 | 627 | unlock_page(page); |
263630e8 | 628 | put_page(page); |
854e9ed0 MK |
629 | pte = pte_offset_map_lock(mm, pmd, addr, &ptl); |
630 | pte--; | |
631 | addr -= PAGE_SIZE; | |
632 | continue; | |
633 | } | |
634 | ||
635 | VM_BUG_ON_PAGE(PageTransCompound(page), page); | |
636 | ||
637 | if (PageSwapCache(page) || PageDirty(page)) { | |
638 | if (!trylock_page(page)) | |
639 | continue; | |
640 | /* | |
641 | * If page is shared with others, we couldn't clear | |
642 | * PG_dirty of the page. | |
643 | */ | |
644 | if (page_mapcount(page) != 1) { | |
645 | unlock_page(page); | |
646 | continue; | |
647 | } | |
648 | ||
649 | if (PageSwapCache(page) && !try_to_free_swap(page)) { | |
650 | unlock_page(page); | |
651 | continue; | |
652 | } | |
653 | ||
654 | ClearPageDirty(page); | |
655 | unlock_page(page); | |
656 | } | |
657 | ||
658 | if (pte_young(ptent) || pte_dirty(ptent)) { | |
659 | /* | |
660 | * Some of architecture(ex, PPC) don't update TLB | |
661 | * with set_pte_at and tlb_remove_tlb_entry so for | |
662 | * the portability, remap the pte with old|clean | |
663 | * after pte clearing. | |
664 | */ | |
665 | ptent = ptep_get_and_clear_full(mm, addr, pte, | |
666 | tlb->fullmm); | |
667 | ||
668 | ptent = pte_mkold(ptent); | |
669 | ptent = pte_mkclean(ptent); | |
670 | set_pte_at(mm, addr, pte, ptent); | |
671 | tlb_remove_tlb_entry(tlb, pte, addr); | |
672 | } | |
802a3a92 | 673 | mark_page_lazyfree(page); |
854e9ed0 MK |
674 | } |
675 | out: | |
64b42bc1 MK |
676 | if (nr_swap) { |
677 | if (current->mm == mm) | |
678 | sync_mm_rss(mm); | |
679 | ||
680 | add_mm_counter(mm, MM_SWAPENTS, nr_swap); | |
681 | } | |
854e9ed0 MK |
682 | arch_leave_lazy_mmu_mode(); |
683 | pte_unmap_unlock(orig_pte, ptl); | |
684 | cond_resched(); | |
b8d3c4c3 | 685 | next: |
854e9ed0 MK |
686 | return 0; |
687 | } | |
688 | ||
7b86ac33 CH |
689 | static const struct mm_walk_ops madvise_free_walk_ops = { |
690 | .pmd_entry = madvise_free_pte_range, | |
691 | }; | |
854e9ed0 MK |
692 | |
693 | static int madvise_free_single_vma(struct vm_area_struct *vma, | |
694 | unsigned long start_addr, unsigned long end_addr) | |
695 | { | |
854e9ed0 | 696 | struct mm_struct *mm = vma->vm_mm; |
ac46d4f3 | 697 | struct mmu_notifier_range range; |
854e9ed0 MK |
698 | struct mmu_gather tlb; |
699 | ||
854e9ed0 MK |
700 | /* MADV_FREE works for only anon vma at the moment */ |
701 | if (!vma_is_anonymous(vma)) | |
702 | return -EINVAL; | |
703 | ||
ac46d4f3 JG |
704 | range.start = max(vma->vm_start, start_addr); |
705 | if (range.start >= vma->vm_end) | |
854e9ed0 | 706 | return -EINVAL; |
ac46d4f3 JG |
707 | range.end = min(vma->vm_end, end_addr); |
708 | if (range.end <= vma->vm_start) | |
854e9ed0 | 709 | return -EINVAL; |
7269f999 | 710 | mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, mm, |
6f4f13e8 | 711 | range.start, range.end); |
854e9ed0 MK |
712 | |
713 | lru_add_drain(); | |
ac46d4f3 | 714 | tlb_gather_mmu(&tlb, mm, range.start, range.end); |
854e9ed0 MK |
715 | update_hiwater_rss(mm); |
716 | ||
ac46d4f3 | 717 | mmu_notifier_invalidate_range_start(&range); |
7b86ac33 CH |
718 | tlb_start_vma(&tlb, vma); |
719 | walk_page_range(vma->vm_mm, range.start, range.end, | |
720 | &madvise_free_walk_ops, &tlb); | |
721 | tlb_end_vma(&tlb, vma); | |
ac46d4f3 JG |
722 | mmu_notifier_invalidate_range_end(&range); |
723 | tlb_finish_mmu(&tlb, range.start, range.end); | |
854e9ed0 MK |
724 | |
725 | return 0; | |
726 | } | |
727 | ||
1da177e4 LT |
728 | /* |
729 | * Application no longer needs these pages. If the pages are dirty, | |
730 | * it's OK to just throw them away. The app will be more careful about | |
731 | * data it wants to keep. Be sure to free swap resources too. The | |
7e6cbea3 | 732 | * zap_page_range call sets things up for shrink_active_list to actually free |
1da177e4 LT |
733 | * these pages later if no one else has touched them in the meantime, |
734 | * although we could add these pages to a global reuse list for | |
7e6cbea3 | 735 | * shrink_active_list to pick up before reclaiming other pages. |
1da177e4 LT |
736 | * |
737 | * NB: This interface discards data rather than pushes it out to swap, | |
738 | * as some implementations do. This has performance implications for | |
739 | * applications like large transactional databases which want to discard | |
740 | * pages in anonymous maps after committing to backing store the data | |
741 | * that was kept in them. There is no reason to write this data out to | |
742 | * the swap area if the application is discarding it. | |
743 | * | |
744 | * An interface that causes the system to free clean pages and flush | |
745 | * dirty pages is already available as msync(MS_INVALIDATE). | |
746 | */ | |
230ca982 MR |
747 | static long madvise_dontneed_single_vma(struct vm_area_struct *vma, |
748 | unsigned long start, unsigned long end) | |
749 | { | |
750 | zap_page_range(vma, start, end - start); | |
751 | return 0; | |
752 | } | |
753 | ||
754 | static long madvise_dontneed_free(struct vm_area_struct *vma, | |
755 | struct vm_area_struct **prev, | |
756 | unsigned long start, unsigned long end, | |
757 | int behavior) | |
1da177e4 | 758 | { |
05b74384 | 759 | *prev = vma; |
9c276cc6 | 760 | if (!can_madv_lru_vma(vma)) |
1da177e4 LT |
761 | return -EINVAL; |
762 | ||
70ccb92f AA |
763 | if (!userfaultfd_remove(vma, start, end)) { |
764 | *prev = NULL; /* mmap_sem has been dropped, prev is stale */ | |
765 | ||
766 | down_read(¤t->mm->mmap_sem); | |
767 | vma = find_vma(current->mm, start); | |
768 | if (!vma) | |
769 | return -ENOMEM; | |
770 | if (start < vma->vm_start) { | |
771 | /* | |
772 | * This "vma" under revalidation is the one | |
773 | * with the lowest vma->vm_start where start | |
774 | * is also < vma->vm_end. If start < | |
775 | * vma->vm_start it means an hole materialized | |
776 | * in the user address space within the | |
230ca982 MR |
777 | * virtual range passed to MADV_DONTNEED |
778 | * or MADV_FREE. | |
70ccb92f AA |
779 | */ |
780 | return -ENOMEM; | |
781 | } | |
9c276cc6 | 782 | if (!can_madv_lru_vma(vma)) |
70ccb92f AA |
783 | return -EINVAL; |
784 | if (end > vma->vm_end) { | |
785 | /* | |
786 | * Don't fail if end > vma->vm_end. If the old | |
787 | * vma was splitted while the mmap_sem was | |
788 | * released the effect of the concurrent | |
230ca982 | 789 | * operation may not cause madvise() to |
70ccb92f AA |
790 | * have an undefined result. There may be an |
791 | * adjacent next vma that we'll walk | |
792 | * next. userfaultfd_remove() will generate an | |
793 | * UFFD_EVENT_REMOVE repetition on the | |
794 | * end-vma->vm_end range, but the manager can | |
795 | * handle a repetition fine. | |
796 | */ | |
797 | end = vma->vm_end; | |
798 | } | |
799 | VM_WARN_ON(start >= end); | |
800 | } | |
230ca982 MR |
801 | |
802 | if (behavior == MADV_DONTNEED) | |
803 | return madvise_dontneed_single_vma(vma, start, end); | |
804 | else if (behavior == MADV_FREE) | |
805 | return madvise_free_single_vma(vma, start, end); | |
806 | else | |
807 | return -EINVAL; | |
1da177e4 LT |
808 | } |
809 | ||
f6b3ec23 BP |
810 | /* |
811 | * Application wants to free up the pages and associated backing store. | |
812 | * This is effectively punching a hole into the middle of a file. | |
f6b3ec23 BP |
813 | */ |
814 | static long madvise_remove(struct vm_area_struct *vma, | |
00e9fa2d | 815 | struct vm_area_struct **prev, |
f6b3ec23 BP |
816 | unsigned long start, unsigned long end) |
817 | { | |
3f31d075 | 818 | loff_t offset; |
90ed52eb | 819 | int error; |
9ab4233d | 820 | struct file *f; |
f6b3ec23 | 821 | |
90ed52eb | 822 | *prev = NULL; /* tell sys_madvise we drop mmap_sem */ |
00e9fa2d | 823 | |
72079ba0 | 824 | if (vma->vm_flags & VM_LOCKED) |
f6b3ec23 BP |
825 | return -EINVAL; |
826 | ||
9ab4233d AL |
827 | f = vma->vm_file; |
828 | ||
829 | if (!f || !f->f_mapping || !f->f_mapping->host) { | |
f6b3ec23 BP |
830 | return -EINVAL; |
831 | } | |
832 | ||
69cf0fac HD |
833 | if ((vma->vm_flags & (VM_SHARED|VM_WRITE)) != (VM_SHARED|VM_WRITE)) |
834 | return -EACCES; | |
835 | ||
f6b3ec23 BP |
836 | offset = (loff_t)(start - vma->vm_start) |
837 | + ((loff_t)vma->vm_pgoff << PAGE_SHIFT); | |
90ed52eb | 838 | |
9ab4233d AL |
839 | /* |
840 | * Filesystem's fallocate may need to take i_mutex. We need to | |
841 | * explicitly grab a reference because the vma (and hence the | |
842 | * vma's reference to the file) can go away as soon as we drop | |
843 | * mmap_sem. | |
844 | */ | |
845 | get_file(f); | |
70ccb92f AA |
846 | if (userfaultfd_remove(vma, start, end)) { |
847 | /* mmap_sem was not released by userfaultfd_remove() */ | |
848 | up_read(¤t->mm->mmap_sem); | |
849 | } | |
72c72bdf | 850 | error = vfs_fallocate(f, |
3f31d075 HD |
851 | FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE, |
852 | offset, end - start); | |
9ab4233d | 853 | fput(f); |
0a27a14a | 854 | down_read(¤t->mm->mmap_sem); |
90ed52eb | 855 | return error; |
f6b3ec23 BP |
856 | } |
857 | ||
9893e49d AK |
858 | #ifdef CONFIG_MEMORY_FAILURE |
859 | /* | |
860 | * Error injection support for memory error handling. | |
861 | */ | |
97167a76 AK |
862 | static int madvise_inject_error(int behavior, |
863 | unsigned long start, unsigned long end) | |
9893e49d | 864 | { |
97167a76 | 865 | struct page *page; |
c461ad6a | 866 | struct zone *zone; |
19bfbe22 | 867 | unsigned int order; |
97167a76 | 868 | |
9893e49d AK |
869 | if (!capable(CAP_SYS_ADMIN)) |
870 | return -EPERM; | |
97167a76 | 871 | |
19bfbe22 AM |
872 | |
873 | for (; start < end; start += PAGE_SIZE << order) { | |
23e7b5c2 | 874 | unsigned long pfn; |
325c4ef5 AM |
875 | int ret; |
876 | ||
97167a76 | 877 | ret = get_user_pages_fast(start, 1, 0, &page); |
9893e49d AK |
878 | if (ret != 1) |
879 | return ret; | |
23e7b5c2 | 880 | pfn = page_to_pfn(page); |
325c4ef5 | 881 | |
19bfbe22 AM |
882 | /* |
883 | * When soft offlining hugepages, after migrating the page | |
884 | * we dissolve it, therefore in the second loop "page" will | |
885 | * no longer be a compound page, and order will be 0. | |
886 | */ | |
887 | order = compound_order(compound_head(page)); | |
888 | ||
97167a76 AK |
889 | if (PageHWPoison(page)) { |
890 | put_page(page); | |
29b4eede WL |
891 | continue; |
892 | } | |
97167a76 AK |
893 | |
894 | if (behavior == MADV_SOFT_OFFLINE) { | |
895 | pr_info("Soft offlining pfn %#lx at process virtual address %#lx\n", | |
23e7b5c2 | 896 | pfn, start); |
97167a76 | 897 | |
feec24a6 | 898 | ret = soft_offline_page(pfn, MF_COUNT_INCREASED); |
afcf938e | 899 | if (ret) |
8302423b | 900 | return ret; |
afcf938e AK |
901 | continue; |
902 | } | |
23e7b5c2 | 903 | |
97167a76 | 904 | pr_info("Injecting memory failure for pfn %#lx at process virtual address %#lx\n", |
23e7b5c2 | 905 | pfn, start); |
97167a76 | 906 | |
23e7b5c2 DW |
907 | /* |
908 | * Drop the page reference taken by get_user_pages_fast(). In | |
909 | * the absence of MF_COUNT_INCREASED the memory_failure() | |
910 | * routine is responsible for pinning the page to prevent it | |
911 | * from being released back to the page allocator. | |
912 | */ | |
913 | put_page(page); | |
914 | ret = memory_failure(pfn, 0); | |
23a003bf NH |
915 | if (ret) |
916 | return ret; | |
9893e49d | 917 | } |
c461ad6a MG |
918 | |
919 | /* Ensure that all poisoned pages are removed from per-cpu lists */ | |
920 | for_each_populated_zone(zone) | |
921 | drain_all_pages(zone); | |
922 | ||
325c4ef5 | 923 | return 0; |
9893e49d AK |
924 | } |
925 | #endif | |
926 | ||
165cd402 | 927 | static long |
928 | madvise_vma(struct vm_area_struct *vma, struct vm_area_struct **prev, | |
929 | unsigned long start, unsigned long end, int behavior) | |
1da177e4 | 930 | { |
1da177e4 | 931 | switch (behavior) { |
f6b3ec23 | 932 | case MADV_REMOVE: |
3866ea90 | 933 | return madvise_remove(vma, prev, start, end); |
1da177e4 | 934 | case MADV_WILLNEED: |
3866ea90 | 935 | return madvise_willneed(vma, prev, start, end); |
9c276cc6 MK |
936 | case MADV_COLD: |
937 | return madvise_cold(vma, prev, start, end); | |
1a4e58cc MK |
938 | case MADV_PAGEOUT: |
939 | return madvise_pageout(vma, prev, start, end); | |
854e9ed0 | 940 | case MADV_FREE: |
1da177e4 | 941 | case MADV_DONTNEED: |
230ca982 | 942 | return madvise_dontneed_free(vma, prev, start, end, behavior); |
1da177e4 | 943 | default: |
3866ea90 | 944 | return madvise_behavior(vma, prev, start, end, behavior); |
1da177e4 | 945 | } |
1da177e4 LT |
946 | } |
947 | ||
1ecef9ed | 948 | static bool |
75927af8 NP |
949 | madvise_behavior_valid(int behavior) |
950 | { | |
951 | switch (behavior) { | |
952 | case MADV_DOFORK: | |
953 | case MADV_DONTFORK: | |
954 | case MADV_NORMAL: | |
955 | case MADV_SEQUENTIAL: | |
956 | case MADV_RANDOM: | |
957 | case MADV_REMOVE: | |
958 | case MADV_WILLNEED: | |
959 | case MADV_DONTNEED: | |
854e9ed0 | 960 | case MADV_FREE: |
9c276cc6 | 961 | case MADV_COLD: |
1a4e58cc | 962 | case MADV_PAGEOUT: |
f8af4da3 HD |
963 | #ifdef CONFIG_KSM |
964 | case MADV_MERGEABLE: | |
965 | case MADV_UNMERGEABLE: | |
0af4e98b AA |
966 | #endif |
967 | #ifdef CONFIG_TRANSPARENT_HUGEPAGE | |
968 | case MADV_HUGEPAGE: | |
a664b2d8 | 969 | case MADV_NOHUGEPAGE: |
f8af4da3 | 970 | #endif |
accb61fe JB |
971 | case MADV_DONTDUMP: |
972 | case MADV_DODUMP: | |
d2cd9ede RR |
973 | case MADV_WIPEONFORK: |
974 | case MADV_KEEPONFORK: | |
5e451be7 AK |
975 | #ifdef CONFIG_MEMORY_FAILURE |
976 | case MADV_SOFT_OFFLINE: | |
977 | case MADV_HWPOISON: | |
978 | #endif | |
1ecef9ed | 979 | return true; |
75927af8 NP |
980 | |
981 | default: | |
1ecef9ed | 982 | return false; |
75927af8 NP |
983 | } |
984 | } | |
3866ea90 | 985 | |
1da177e4 LT |
986 | /* |
987 | * The madvise(2) system call. | |
988 | * | |
989 | * Applications can use madvise() to advise the kernel how it should | |
990 | * handle paging I/O in this VM area. The idea is to help the kernel | |
991 | * use appropriate read-ahead and caching techniques. The information | |
992 | * provided is advisory only, and can be safely disregarded by the | |
993 | * kernel without affecting the correct operation of the application. | |
994 | * | |
995 | * behavior values: | |
996 | * MADV_NORMAL - the default behavior is to read clusters. This | |
997 | * results in some read-ahead and read-behind. | |
998 | * MADV_RANDOM - the system should read the minimum amount of data | |
999 | * on any access, since it is unlikely that the appli- | |
1000 | * cation will need more than what it asks for. | |
1001 | * MADV_SEQUENTIAL - pages in the given range will probably be accessed | |
1002 | * once, so they can be aggressively read ahead, and | |
1003 | * can be freed soon after they are accessed. | |
1004 | * MADV_WILLNEED - the application is notifying the system to read | |
1005 | * some pages ahead. | |
1006 | * MADV_DONTNEED - the application is finished with the given range, | |
1007 | * so the kernel can free resources associated with it. | |
d7206a70 NH |
1008 | * MADV_FREE - the application marks pages in the given range as lazy free, |
1009 | * where actual purges are postponed until memory pressure happens. | |
f6b3ec23 BP |
1010 | * MADV_REMOVE - the application wants to free up the given range of |
1011 | * pages and associated backing store. | |
3866ea90 HD |
1012 | * MADV_DONTFORK - omit this area from child's address space when forking: |
1013 | * typically, to avoid COWing pages pinned by get_user_pages(). | |
1014 | * MADV_DOFORK - cancel MADV_DONTFORK: no longer omit this area when forking. | |
c02c3009 YS |
1015 | * MADV_WIPEONFORK - present the child process with zero-filled memory in this |
1016 | * range after a fork. | |
1017 | * MADV_KEEPONFORK - undo the effect of MADV_WIPEONFORK | |
d7206a70 NH |
1018 | * MADV_HWPOISON - trigger memory error handler as if the given memory range |
1019 | * were corrupted by unrecoverable hardware memory failure. | |
1020 | * MADV_SOFT_OFFLINE - try to soft-offline the given range of memory. | |
f8af4da3 HD |
1021 | * MADV_MERGEABLE - the application recommends that KSM try to merge pages in |
1022 | * this area with pages of identical content from other such areas. | |
1023 | * MADV_UNMERGEABLE- cancel MADV_MERGEABLE: no longer merge pages with others. | |
d7206a70 NH |
1024 | * MADV_HUGEPAGE - the application wants to back the given range by transparent |
1025 | * huge pages in the future. Existing pages might be coalesced and | |
1026 | * new pages might be allocated as THP. | |
1027 | * MADV_NOHUGEPAGE - mark the given range as not worth being backed by | |
1028 | * transparent huge pages so the existing pages will not be | |
1029 | * coalesced into THP and new pages will not be allocated as THP. | |
1030 | * MADV_DONTDUMP - the application wants to prevent pages in the given range | |
1031 | * from being included in its core dump. | |
1032 | * MADV_DODUMP - cancel MADV_DONTDUMP: no longer exclude from core dump. | |
1da177e4 LT |
1033 | * |
1034 | * return values: | |
1035 | * zero - success | |
1036 | * -EINVAL - start + len < 0, start is not page-aligned, | |
1037 | * "behavior" is not a valid value, or application | |
c02c3009 YS |
1038 | * is attempting to release locked or shared pages, |
1039 | * or the specified address range includes file, Huge TLB, | |
1040 | * MAP_SHARED or VMPFNMAP range. | |
1da177e4 LT |
1041 | * -ENOMEM - addresses in the specified range are not currently |
1042 | * mapped, or are outside the AS of the process. | |
1043 | * -EIO - an I/O error occurred while paging in data. | |
1044 | * -EBADF - map exists, but area maps something that isn't a file. | |
1045 | * -EAGAIN - a kernel resource was temporarily unavailable. | |
1046 | */ | |
3480b257 | 1047 | SYSCALL_DEFINE3(madvise, unsigned long, start, size_t, len_in, int, behavior) |
1da177e4 | 1048 | { |
05b74384 | 1049 | unsigned long end, tmp; |
ec9bed9d | 1050 | struct vm_area_struct *vma, *prev; |
1da177e4 LT |
1051 | int unmapped_error = 0; |
1052 | int error = -EINVAL; | |
f7977793 | 1053 | int write; |
1da177e4 | 1054 | size_t len; |
1998cc04 | 1055 | struct blk_plug plug; |
1da177e4 | 1056 | |
057d3389 AK |
1057 | start = untagged_addr(start); |
1058 | ||
75927af8 NP |
1059 | if (!madvise_behavior_valid(behavior)) |
1060 | return error; | |
1061 | ||
1da177e4 | 1062 | if (start & ~PAGE_MASK) |
84d96d89 | 1063 | return error; |
1da177e4 LT |
1064 | len = (len_in + ~PAGE_MASK) & PAGE_MASK; |
1065 | ||
1066 | /* Check to see whether len was rounded up from small -ve to zero */ | |
1067 | if (len_in && !len) | |
84d96d89 | 1068 | return error; |
1da177e4 LT |
1069 | |
1070 | end = start + len; | |
1071 | if (end < start) | |
84d96d89 | 1072 | return error; |
1da177e4 LT |
1073 | |
1074 | error = 0; | |
1075 | if (end == start) | |
84d96d89 RV |
1076 | return error; |
1077 | ||
5e451be7 AK |
1078 | #ifdef CONFIG_MEMORY_FAILURE |
1079 | if (behavior == MADV_HWPOISON || behavior == MADV_SOFT_OFFLINE) | |
1080 | return madvise_inject_error(behavior, start, start + len_in); | |
1081 | #endif | |
1082 | ||
84d96d89 | 1083 | write = madvise_need_mmap_write(behavior); |
dc0ef0df MH |
1084 | if (write) { |
1085 | if (down_write_killable(¤t->mm->mmap_sem)) | |
1086 | return -EINTR; | |
1087 | } else { | |
84d96d89 | 1088 | down_read(¤t->mm->mmap_sem); |
dc0ef0df | 1089 | } |
1da177e4 LT |
1090 | |
1091 | /* | |
1092 | * If the interval [start,end) covers some unmapped address | |
1093 | * ranges, just ignore them, but return -ENOMEM at the end. | |
05b74384 | 1094 | * - different from the way of handling in mlock etc. |
1da177e4 | 1095 | */ |
05b74384 | 1096 | vma = find_vma_prev(current->mm, start, &prev); |
836d5ffd HD |
1097 | if (vma && start > vma->vm_start) |
1098 | prev = vma; | |
1099 | ||
1998cc04 | 1100 | blk_start_plug(&plug); |
1da177e4 LT |
1101 | for (;;) { |
1102 | /* Still start < end. */ | |
1103 | error = -ENOMEM; | |
1104 | if (!vma) | |
84d96d89 | 1105 | goto out; |
1da177e4 | 1106 | |
05b74384 | 1107 | /* Here start < (end|vma->vm_end). */ |
1da177e4 LT |
1108 | if (start < vma->vm_start) { |
1109 | unmapped_error = -ENOMEM; | |
1110 | start = vma->vm_start; | |
05b74384 | 1111 | if (start >= end) |
84d96d89 | 1112 | goto out; |
1da177e4 LT |
1113 | } |
1114 | ||
05b74384 PM |
1115 | /* Here vma->vm_start <= start < (end|vma->vm_end) */ |
1116 | tmp = vma->vm_end; | |
1117 | if (end < tmp) | |
1118 | tmp = end; | |
1da177e4 | 1119 | |
05b74384 PM |
1120 | /* Here vma->vm_start <= start < tmp <= (end|vma->vm_end). */ |
1121 | error = madvise_vma(vma, &prev, start, tmp, behavior); | |
1da177e4 | 1122 | if (error) |
84d96d89 | 1123 | goto out; |
05b74384 | 1124 | start = tmp; |
90ed52eb | 1125 | if (prev && start < prev->vm_end) |
05b74384 PM |
1126 | start = prev->vm_end; |
1127 | error = unmapped_error; | |
1128 | if (start >= end) | |
84d96d89 | 1129 | goto out; |
90ed52eb HD |
1130 | if (prev) |
1131 | vma = prev->vm_next; | |
1132 | else /* madvise_remove dropped mmap_sem */ | |
1133 | vma = find_vma(current->mm, start); | |
1da177e4 | 1134 | } |
1da177e4 | 1135 | out: |
84d96d89 | 1136 | blk_finish_plug(&plug); |
f7977793 | 1137 | if (write) |
0a27a14a NP |
1138 | up_write(¤t->mm->mmap_sem); |
1139 | else | |
1140 | up_read(¤t->mm->mmap_sem); | |
1141 | ||
1da177e4 LT |
1142 | return error; |
1143 | } |