Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * linux/mm/mlock.c | |
3 | * | |
4 | * (C) Copyright 1995 Linus Torvalds | |
5 | * (C) Copyright 2002 Christoph Hellwig | |
6 | */ | |
7 | ||
c59ede7b | 8 | #include <linux/capability.h> |
1da177e4 LT |
9 | #include <linux/mman.h> |
10 | #include <linux/mm.h> | |
b291f000 NP |
11 | #include <linux/swap.h> |
12 | #include <linux/swapops.h> | |
13 | #include <linux/pagemap.h> | |
1da177e4 LT |
14 | #include <linux/mempolicy.h> |
15 | #include <linux/syscalls.h> | |
e8edc6e0 AD |
16 | #include <linux/sched.h> |
17 | #include <linux/module.h> | |
b291f000 NP |
18 | #include <linux/rmap.h> |
19 | #include <linux/mmzone.h> | |
20 | #include <linux/hugetlb.h> | |
21 | ||
22 | #include "internal.h" | |
1da177e4 | 23 | |
e8edc6e0 AD |
24 | int can_do_mlock(void) |
25 | { | |
26 | if (capable(CAP_IPC_LOCK)) | |
27 | return 1; | |
59e99e5b | 28 | if (rlimit(RLIMIT_MEMLOCK) != 0) |
e8edc6e0 AD |
29 | return 1; |
30 | return 0; | |
31 | } | |
32 | EXPORT_SYMBOL(can_do_mlock); | |
1da177e4 | 33 | |
b291f000 NP |
34 | /* |
35 | * Mlocked pages are marked with PageMlocked() flag for efficient testing | |
36 | * in vmscan and, possibly, the fault path; and to support semi-accurate | |
37 | * statistics. | |
38 | * | |
39 | * An mlocked page [PageMlocked(page)] is unevictable. As such, it will | |
40 | * be placed on the LRU "unevictable" list, rather than the [in]active lists. | |
41 | * The unevictable list is an LRU sibling list to the [in]active lists. | |
42 | * PageUnevictable is set to indicate the unevictable state. | |
43 | * | |
44 | * When lazy mlocking via vmscan, it is important to ensure that the | |
45 | * vma's VM_LOCKED status is not concurrently being modified, otherwise we | |
46 | * may have mlocked a page that is being munlocked. So lazy mlock must take | |
47 | * the mmap_sem for read, and verify that the vma really is locked | |
48 | * (see mm/rmap.c). | |
49 | */ | |
50 | ||
51 | /* | |
52 | * LRU accounting for clear_page_mlock() | |
53 | */ | |
54 | void __clear_page_mlock(struct page *page) | |
55 | { | |
56 | VM_BUG_ON(!PageLocked(page)); | |
57 | ||
58 | if (!page->mapping) { /* truncated ? */ | |
59 | return; | |
60 | } | |
61 | ||
5344b7e6 NP |
62 | dec_zone_page_state(page, NR_MLOCK); |
63 | count_vm_event(UNEVICTABLE_PGCLEARED); | |
b291f000 NP |
64 | if (!isolate_lru_page(page)) { |
65 | putback_lru_page(page); | |
66 | } else { | |
67 | /* | |
8891d6da | 68 | * We lost the race. the page already moved to evictable list. |
b291f000 | 69 | */ |
8891d6da | 70 | if (PageUnevictable(page)) |
5344b7e6 | 71 | count_vm_event(UNEVICTABLE_PGSTRANDED); |
b291f000 NP |
72 | } |
73 | } | |
74 | ||
75 | /* | |
76 | * Mark page as mlocked if not already. | |
77 | * If page on LRU, isolate and putback to move to unevictable list. | |
78 | */ | |
79 | void mlock_vma_page(struct page *page) | |
80 | { | |
81 | BUG_ON(!PageLocked(page)); | |
82 | ||
5344b7e6 NP |
83 | if (!TestSetPageMlocked(page)) { |
84 | inc_zone_page_state(page, NR_MLOCK); | |
85 | count_vm_event(UNEVICTABLE_PGMLOCKED); | |
86 | if (!isolate_lru_page(page)) | |
87 | putback_lru_page(page); | |
88 | } | |
b291f000 NP |
89 | } |
90 | ||
6927c1dd LS |
91 | /** |
92 | * munlock_vma_page - munlock a vma page | |
93 | * @page - page to be unlocked | |
b291f000 | 94 | * |
6927c1dd LS |
95 | * called from munlock()/munmap() path with page supposedly on the LRU. |
96 | * When we munlock a page, because the vma where we found the page is being | |
97 | * munlock()ed or munmap()ed, we want to check whether other vmas hold the | |
98 | * page locked so that we can leave it on the unevictable lru list and not | |
99 | * bother vmscan with it. However, to walk the page's rmap list in | |
100 | * try_to_munlock() we must isolate the page from the LRU. If some other | |
101 | * task has removed the page from the LRU, we won't be able to do that. | |
102 | * So we clear the PageMlocked as we might not get another chance. If we | |
103 | * can't isolate the page, we leave it for putback_lru_page() and vmscan | |
104 | * [page_referenced()/try_to_unmap()] to deal with. | |
b291f000 | 105 | */ |
73848b46 | 106 | void munlock_vma_page(struct page *page) |
b291f000 NP |
107 | { |
108 | BUG_ON(!PageLocked(page)); | |
109 | ||
5344b7e6 NP |
110 | if (TestClearPageMlocked(page)) { |
111 | dec_zone_page_state(page, NR_MLOCK); | |
112 | if (!isolate_lru_page(page)) { | |
113 | int ret = try_to_munlock(page); | |
114 | /* | |
115 | * did try_to_unlock() succeed or punt? | |
116 | */ | |
53f79acb | 117 | if (ret != SWAP_MLOCK) |
5344b7e6 NP |
118 | count_vm_event(UNEVICTABLE_PGMUNLOCKED); |
119 | ||
120 | putback_lru_page(page); | |
121 | } else { | |
122 | /* | |
6927c1dd LS |
123 | * Some other task has removed the page from the LRU. |
124 | * putback_lru_page() will take care of removing the | |
125 | * page from the unevictable list, if necessary. | |
126 | * vmscan [page_referenced()] will move the page back | |
127 | * to the unevictable list if some other vma has it | |
128 | * mlocked. | |
5344b7e6 NP |
129 | */ |
130 | if (PageUnevictable(page)) | |
131 | count_vm_event(UNEVICTABLE_PGSTRANDED); | |
132 | else | |
133 | count_vm_event(UNEVICTABLE_PGMUNLOCKED); | |
134 | } | |
b291f000 NP |
135 | } |
136 | } | |
137 | ||
ba470de4 | 138 | /** |
408e82b7 | 139 | * __mlock_vma_pages_range() - mlock a range of pages in the vma. |
ba470de4 RR |
140 | * @vma: target vma |
141 | * @start: start address | |
142 | * @end: end address | |
ba470de4 | 143 | * |
408e82b7 | 144 | * This takes care of making the pages present too. |
b291f000 | 145 | * |
ba470de4 | 146 | * return 0 on success, negative error code on error. |
b291f000 | 147 | * |
ba470de4 | 148 | * vma->vm_mm->mmap_sem must be held for at least read. |
b291f000 | 149 | */ |
ba470de4 | 150 | static long __mlock_vma_pages_range(struct vm_area_struct *vma, |
408e82b7 | 151 | unsigned long start, unsigned long end) |
b291f000 NP |
152 | { |
153 | struct mm_struct *mm = vma->vm_mm; | |
154 | unsigned long addr = start; | |
155 | struct page *pages[16]; /* 16 gives a reasonable batch */ | |
b291f000 | 156 | int nr_pages = (end - start) / PAGE_SIZE; |
72eb8c67 | 157 | int ret = 0; |
408e82b7 | 158 | int gup_flags; |
ba470de4 RR |
159 | |
160 | VM_BUG_ON(start & ~PAGE_MASK); | |
161 | VM_BUG_ON(end & ~PAGE_MASK); | |
162 | VM_BUG_ON(start < vma->vm_start); | |
163 | VM_BUG_ON(end > vma->vm_end); | |
408e82b7 | 164 | VM_BUG_ON(!rwsem_is_locked(&mm->mmap_sem)); |
b291f000 | 165 | |
58fa879e | 166 | gup_flags = FOLL_TOUCH | FOLL_GET; |
ba470de4 | 167 | if (vma->vm_flags & VM_WRITE) |
58fa879e | 168 | gup_flags |= FOLL_WRITE; |
b291f000 | 169 | |
d7824370 LT |
170 | /* We don't try to access the guard page of a stack vma */ |
171 | if (vma->vm_flags & VM_GROWSDOWN) { | |
172 | if (start == vma->vm_start) { | |
173 | start += PAGE_SIZE; | |
174 | nr_pages--; | |
175 | } | |
176 | } | |
177 | ||
b291f000 NP |
178 | while (nr_pages > 0) { |
179 | int i; | |
180 | ||
181 | cond_resched(); | |
182 | ||
183 | /* | |
184 | * get_user_pages makes pages present if we are | |
185 | * setting mlock. and this extra reference count will | |
186 | * disable migration of this page. However, page may | |
187 | * still be truncated out from under us. | |
188 | */ | |
ba470de4 | 189 | ret = __get_user_pages(current, mm, addr, |
b291f000 | 190 | min_t(int, nr_pages, ARRAY_SIZE(pages)), |
ba470de4 | 191 | gup_flags, pages, NULL); |
b291f000 NP |
192 | /* |
193 | * This can happen for, e.g., VM_NONLINEAR regions before | |
194 | * a page has been allocated and mapped at a given offset, | |
195 | * or for addresses that map beyond end of a file. | |
408e82b7 | 196 | * We'll mlock the pages if/when they get faulted in. |
b291f000 NP |
197 | */ |
198 | if (ret < 0) | |
199 | break; | |
b291f000 NP |
200 | |
201 | lru_add_drain(); /* push cached pages to LRU */ | |
202 | ||
203 | for (i = 0; i < ret; i++) { | |
204 | struct page *page = pages[i]; | |
205 | ||
6e919717 HD |
206 | if (page->mapping) { |
207 | /* | |
208 | * That preliminary check is mainly to avoid | |
209 | * the pointless overhead of lock_page on the | |
210 | * ZERO_PAGE: which might bounce very badly if | |
211 | * there is contention. However, we're still | |
212 | * dirtying its cacheline with get/put_page: | |
213 | * we'll add another __get_user_pages flag to | |
214 | * avoid it if that case turns out to matter. | |
215 | */ | |
216 | lock_page(page); | |
217 | /* | |
218 | * Because we lock page here and migration is | |
219 | * blocked by the elevated reference, we need | |
220 | * only check for file-cache page truncation. | |
221 | */ | |
222 | if (page->mapping) | |
223 | mlock_vma_page(page); | |
224 | unlock_page(page); | |
225 | } | |
408e82b7 | 226 | put_page(page); /* ref from get_user_pages() */ |
b291f000 | 227 | } |
408e82b7 HD |
228 | |
229 | addr += ret * PAGE_SIZE; | |
230 | nr_pages -= ret; | |
9978ad58 | 231 | ret = 0; |
b291f000 NP |
232 | } |
233 | ||
408e82b7 | 234 | return ret; /* 0 or negative error code */ |
9978ad58 LS |
235 | } |
236 | ||
237 | /* | |
238 | * convert get_user_pages() return value to posix mlock() error | |
239 | */ | |
240 | static int __mlock_posix_error_return(long retval) | |
241 | { | |
242 | if (retval == -EFAULT) | |
243 | retval = -ENOMEM; | |
244 | else if (retval == -ENOMEM) | |
245 | retval = -EAGAIN; | |
246 | return retval; | |
b291f000 NP |
247 | } |
248 | ||
ba470de4 RR |
249 | /** |
250 | * mlock_vma_pages_range() - mlock pages in specified vma range. | |
251 | * @vma - the vma containing the specfied address range | |
252 | * @start - starting address in @vma to mlock | |
253 | * @end - end address [+1] in @vma to mlock | |
254 | * | |
255 | * For mmap()/mremap()/expansion of mlocked vma. | |
256 | * | |
257 | * return 0 on success for "normal" vmas. | |
258 | * | |
259 | * return number of pages [> 0] to be removed from locked_vm on success | |
260 | * of "special" vmas. | |
b291f000 | 261 | */ |
ba470de4 | 262 | long mlock_vma_pages_range(struct vm_area_struct *vma, |
b291f000 NP |
263 | unsigned long start, unsigned long end) |
264 | { | |
265 | int nr_pages = (end - start) / PAGE_SIZE; | |
266 | BUG_ON(!(vma->vm_flags & VM_LOCKED)); | |
267 | ||
268 | /* | |
269 | * filter unlockable vmas | |
270 | */ | |
271 | if (vma->vm_flags & (VM_IO | VM_PFNMAP)) | |
272 | goto no_mlock; | |
273 | ||
274 | if (!((vma->vm_flags & (VM_DONTEXPAND | VM_RESERVED)) || | |
275 | is_vm_hugetlb_page(vma) || | |
8edb08ca | 276 | vma == get_gate_vma(current))) { |
8edb08ca | 277 | |
408e82b7 | 278 | __mlock_vma_pages_range(vma, start, end); |
d5b56233 HD |
279 | |
280 | /* Hide errors from mmap() and other callers */ | |
281 | return 0; | |
8edb08ca | 282 | } |
b291f000 NP |
283 | |
284 | /* | |
285 | * User mapped kernel pages or huge pages: | |
286 | * make these pages present to populate the ptes, but | |
287 | * fall thru' to reset VM_LOCKED--no need to unlock, and | |
288 | * return nr_pages so these don't get counted against task's | |
289 | * locked limit. huge pages are already counted against | |
290 | * locked vm limit. | |
291 | */ | |
292 | make_pages_present(start, end); | |
293 | ||
294 | no_mlock: | |
295 | vma->vm_flags &= ~VM_LOCKED; /* and don't come back! */ | |
ba470de4 | 296 | return nr_pages; /* error or pages NOT mlocked */ |
b291f000 NP |
297 | } |
298 | ||
b291f000 | 299 | /* |
ba470de4 RR |
300 | * munlock_vma_pages_range() - munlock all pages in the vma range.' |
301 | * @vma - vma containing range to be munlock()ed. | |
302 | * @start - start address in @vma of the range | |
303 | * @end - end of range in @vma. | |
304 | * | |
305 | * For mremap(), munmap() and exit(). | |
306 | * | |
307 | * Called with @vma VM_LOCKED. | |
308 | * | |
309 | * Returns with VM_LOCKED cleared. Callers must be prepared to | |
310 | * deal with this. | |
311 | * | |
312 | * We don't save and restore VM_LOCKED here because pages are | |
313 | * still on lru. In unmap path, pages might be scanned by reclaim | |
314 | * and re-mlocked by try_to_{munlock|unmap} before we unmap and | |
315 | * free them. This will result in freeing mlocked pages. | |
b291f000 | 316 | */ |
ba470de4 | 317 | void munlock_vma_pages_range(struct vm_area_struct *vma, |
408e82b7 | 318 | unsigned long start, unsigned long end) |
b291f000 | 319 | { |
408e82b7 HD |
320 | unsigned long addr; |
321 | ||
322 | lru_add_drain(); | |
b291f000 | 323 | vma->vm_flags &= ~VM_LOCKED; |
408e82b7 HD |
324 | |
325 | for (addr = start; addr < end; addr += PAGE_SIZE) { | |
6e919717 HD |
326 | struct page *page; |
327 | /* | |
328 | * Although FOLL_DUMP is intended for get_dump_page(), | |
329 | * it just so happens that its special treatment of the | |
330 | * ZERO_PAGE (returning an error instead of doing get_page) | |
331 | * suits munlock very well (and if somehow an abnormal page | |
332 | * has sneaked into the range, we won't oops here: great). | |
333 | */ | |
334 | page = follow_page(vma, addr, FOLL_GET | FOLL_DUMP); | |
335 | if (page && !IS_ERR(page)) { | |
408e82b7 | 336 | lock_page(page); |
6e919717 HD |
337 | /* |
338 | * Like in __mlock_vma_pages_range(), | |
339 | * because we lock page here and migration is | |
340 | * blocked by the elevated reference, we need | |
341 | * only check for file-cache page truncation. | |
342 | */ | |
408e82b7 HD |
343 | if (page->mapping) |
344 | munlock_vma_page(page); | |
345 | unlock_page(page); | |
346 | put_page(page); | |
347 | } | |
348 | cond_resched(); | |
349 | } | |
b291f000 NP |
350 | } |
351 | ||
352 | /* | |
353 | * mlock_fixup - handle mlock[all]/munlock[all] requests. | |
354 | * | |
355 | * Filters out "special" vmas -- VM_LOCKED never gets set for these, and | |
356 | * munlock is a no-op. However, for some special vmas, we go ahead and | |
357 | * populate the ptes via make_pages_present(). | |
358 | * | |
359 | * For vmas that pass the filters, merge/split as appropriate. | |
360 | */ | |
1da177e4 LT |
361 | static int mlock_fixup(struct vm_area_struct *vma, struct vm_area_struct **prev, |
362 | unsigned long start, unsigned long end, unsigned int newflags) | |
363 | { | |
b291f000 | 364 | struct mm_struct *mm = vma->vm_mm; |
1da177e4 | 365 | pgoff_t pgoff; |
b291f000 | 366 | int nr_pages; |
1da177e4 | 367 | int ret = 0; |
b291f000 | 368 | int lock = newflags & VM_LOCKED; |
1da177e4 | 369 | |
b291f000 NP |
370 | if (newflags == vma->vm_flags || |
371 | (vma->vm_flags & (VM_IO | VM_PFNMAP))) | |
372 | goto out; /* don't set VM_LOCKED, don't count */ | |
373 | ||
374 | if ((vma->vm_flags & (VM_DONTEXPAND | VM_RESERVED)) || | |
375 | is_vm_hugetlb_page(vma) || | |
376 | vma == get_gate_vma(current)) { | |
377 | if (lock) | |
378 | make_pages_present(start, end); | |
379 | goto out; /* don't set VM_LOCKED, don't count */ | |
1da177e4 LT |
380 | } |
381 | ||
382 | pgoff = vma->vm_pgoff + ((start - vma->vm_start) >> PAGE_SHIFT); | |
383 | *prev = vma_merge(mm, *prev, start, end, newflags, vma->anon_vma, | |
384 | vma->vm_file, pgoff, vma_policy(vma)); | |
385 | if (*prev) { | |
386 | vma = *prev; | |
387 | goto success; | |
388 | } | |
389 | ||
1da177e4 LT |
390 | if (start != vma->vm_start) { |
391 | ret = split_vma(mm, vma, start, 1); | |
392 | if (ret) | |
393 | goto out; | |
394 | } | |
395 | ||
396 | if (end != vma->vm_end) { | |
397 | ret = split_vma(mm, vma, end, 0); | |
398 | if (ret) | |
399 | goto out; | |
400 | } | |
401 | ||
402 | success: | |
b291f000 NP |
403 | /* |
404 | * Keep track of amount of locked VM. | |
405 | */ | |
406 | nr_pages = (end - start) >> PAGE_SHIFT; | |
407 | if (!lock) | |
408 | nr_pages = -nr_pages; | |
409 | mm->locked_vm += nr_pages; | |
410 | ||
1da177e4 LT |
411 | /* |
412 | * vm_flags is protected by the mmap_sem held in write mode. | |
413 | * It's okay if try_to_unmap_one unmaps a page just after we | |
b291f000 | 414 | * set VM_LOCKED, __mlock_vma_pages_range will bring it back. |
1da177e4 | 415 | */ |
1da177e4 | 416 | |
b291f000 | 417 | if (lock) { |
408e82b7 HD |
418 | vma->vm_flags = newflags; |
419 | ret = __mlock_vma_pages_range(vma, start, end); | |
420 | if (ret < 0) | |
421 | ret = __mlock_posix_error_return(ret); | |
8edb08ca | 422 | } else { |
408e82b7 | 423 | munlock_vma_pages_range(vma, start, end); |
8edb08ca | 424 | } |
1da177e4 | 425 | |
1da177e4 | 426 | out: |
b291f000 | 427 | *prev = vma; |
1da177e4 LT |
428 | return ret; |
429 | } | |
430 | ||
431 | static int do_mlock(unsigned long start, size_t len, int on) | |
432 | { | |
433 | unsigned long nstart, end, tmp; | |
434 | struct vm_area_struct * vma, * prev; | |
435 | int error; | |
436 | ||
437 | len = PAGE_ALIGN(len); | |
438 | end = start + len; | |
439 | if (end < start) | |
440 | return -EINVAL; | |
441 | if (end == start) | |
442 | return 0; | |
443 | vma = find_vma_prev(current->mm, start, &prev); | |
444 | if (!vma || vma->vm_start > start) | |
445 | return -ENOMEM; | |
446 | ||
447 | if (start > vma->vm_start) | |
448 | prev = vma; | |
449 | ||
450 | for (nstart = start ; ; ) { | |
451 | unsigned int newflags; | |
452 | ||
453 | /* Here we know that vma->vm_start <= nstart < vma->vm_end. */ | |
454 | ||
455 | newflags = vma->vm_flags | VM_LOCKED; | |
456 | if (!on) | |
457 | newflags &= ~VM_LOCKED; | |
458 | ||
459 | tmp = vma->vm_end; | |
460 | if (tmp > end) | |
461 | tmp = end; | |
462 | error = mlock_fixup(vma, &prev, nstart, tmp, newflags); | |
463 | if (error) | |
464 | break; | |
465 | nstart = tmp; | |
466 | if (nstart < prev->vm_end) | |
467 | nstart = prev->vm_end; | |
468 | if (nstart >= end) | |
469 | break; | |
470 | ||
471 | vma = prev->vm_next; | |
472 | if (!vma || vma->vm_start != nstart) { | |
473 | error = -ENOMEM; | |
474 | break; | |
475 | } | |
476 | } | |
477 | return error; | |
478 | } | |
479 | ||
6a6160a7 | 480 | SYSCALL_DEFINE2(mlock, unsigned long, start, size_t, len) |
1da177e4 LT |
481 | { |
482 | unsigned long locked; | |
483 | unsigned long lock_limit; | |
484 | int error = -ENOMEM; | |
485 | ||
486 | if (!can_do_mlock()) | |
487 | return -EPERM; | |
488 | ||
8891d6da KM |
489 | lru_add_drain_all(); /* flush pagevec */ |
490 | ||
1da177e4 LT |
491 | down_write(¤t->mm->mmap_sem); |
492 | len = PAGE_ALIGN(len + (start & ~PAGE_MASK)); | |
493 | start &= PAGE_MASK; | |
494 | ||
495 | locked = len >> PAGE_SHIFT; | |
496 | locked += current->mm->locked_vm; | |
497 | ||
59e99e5b | 498 | lock_limit = rlimit(RLIMIT_MEMLOCK); |
1da177e4 LT |
499 | lock_limit >>= PAGE_SHIFT; |
500 | ||
501 | /* check against resource limits */ | |
502 | if ((locked <= lock_limit) || capable(CAP_IPC_LOCK)) | |
503 | error = do_mlock(start, len, 1); | |
504 | up_write(¤t->mm->mmap_sem); | |
505 | return error; | |
506 | } | |
507 | ||
6a6160a7 | 508 | SYSCALL_DEFINE2(munlock, unsigned long, start, size_t, len) |
1da177e4 LT |
509 | { |
510 | int ret; | |
511 | ||
512 | down_write(¤t->mm->mmap_sem); | |
513 | len = PAGE_ALIGN(len + (start & ~PAGE_MASK)); | |
514 | start &= PAGE_MASK; | |
515 | ret = do_mlock(start, len, 0); | |
516 | up_write(¤t->mm->mmap_sem); | |
517 | return ret; | |
518 | } | |
519 | ||
520 | static int do_mlockall(int flags) | |
521 | { | |
522 | struct vm_area_struct * vma, * prev = NULL; | |
523 | unsigned int def_flags = 0; | |
524 | ||
525 | if (flags & MCL_FUTURE) | |
526 | def_flags = VM_LOCKED; | |
527 | current->mm->def_flags = def_flags; | |
528 | if (flags == MCL_FUTURE) | |
529 | goto out; | |
530 | ||
531 | for (vma = current->mm->mmap; vma ; vma = prev->vm_next) { | |
532 | unsigned int newflags; | |
533 | ||
534 | newflags = vma->vm_flags | VM_LOCKED; | |
535 | if (!(flags & MCL_CURRENT)) | |
536 | newflags &= ~VM_LOCKED; | |
537 | ||
538 | /* Ignore errors */ | |
539 | mlock_fixup(vma, &prev, vma->vm_start, vma->vm_end, newflags); | |
540 | } | |
541 | out: | |
542 | return 0; | |
543 | } | |
544 | ||
3480b257 | 545 | SYSCALL_DEFINE1(mlockall, int, flags) |
1da177e4 LT |
546 | { |
547 | unsigned long lock_limit; | |
548 | int ret = -EINVAL; | |
549 | ||
550 | if (!flags || (flags & ~(MCL_CURRENT | MCL_FUTURE))) | |
551 | goto out; | |
552 | ||
553 | ret = -EPERM; | |
554 | if (!can_do_mlock()) | |
555 | goto out; | |
556 | ||
8891d6da KM |
557 | lru_add_drain_all(); /* flush pagevec */ |
558 | ||
1da177e4 LT |
559 | down_write(¤t->mm->mmap_sem); |
560 | ||
59e99e5b | 561 | lock_limit = rlimit(RLIMIT_MEMLOCK); |
1da177e4 LT |
562 | lock_limit >>= PAGE_SHIFT; |
563 | ||
564 | ret = -ENOMEM; | |
565 | if (!(flags & MCL_CURRENT) || (current->mm->total_vm <= lock_limit) || | |
566 | capable(CAP_IPC_LOCK)) | |
567 | ret = do_mlockall(flags); | |
568 | up_write(¤t->mm->mmap_sem); | |
569 | out: | |
570 | return ret; | |
571 | } | |
572 | ||
3480b257 | 573 | SYSCALL_DEFINE0(munlockall) |
1da177e4 LT |
574 | { |
575 | int ret; | |
576 | ||
577 | down_write(¤t->mm->mmap_sem); | |
578 | ret = do_mlockall(0); | |
579 | up_write(¤t->mm->mmap_sem); | |
580 | return ret; | |
581 | } | |
582 | ||
583 | /* | |
584 | * Objects with different lifetime than processes (SHM_LOCK and SHM_HUGETLB | |
585 | * shm segments) get accounted against the user_struct instead. | |
586 | */ | |
587 | static DEFINE_SPINLOCK(shmlock_user_lock); | |
588 | ||
589 | int user_shm_lock(size_t size, struct user_struct *user) | |
590 | { | |
591 | unsigned long lock_limit, locked; | |
592 | int allowed = 0; | |
593 | ||
594 | locked = (size + PAGE_SIZE - 1) >> PAGE_SHIFT; | |
59e99e5b | 595 | lock_limit = rlimit(RLIMIT_MEMLOCK); |
5ed44a40 HB |
596 | if (lock_limit == RLIM_INFINITY) |
597 | allowed = 1; | |
1da177e4 LT |
598 | lock_limit >>= PAGE_SHIFT; |
599 | spin_lock(&shmlock_user_lock); | |
5ed44a40 HB |
600 | if (!allowed && |
601 | locked + user->locked_shm > lock_limit && !capable(CAP_IPC_LOCK)) | |
1da177e4 LT |
602 | goto out; |
603 | get_uid(user); | |
604 | user->locked_shm += locked; | |
605 | allowed = 1; | |
606 | out: | |
607 | spin_unlock(&shmlock_user_lock); | |
608 | return allowed; | |
609 | } | |
610 | ||
611 | void user_shm_unlock(size_t size, struct user_struct *user) | |
612 | { | |
613 | spin_lock(&shmlock_user_lock); | |
614 | user->locked_shm -= (size + PAGE_SIZE - 1) >> PAGE_SHIFT; | |
615 | spin_unlock(&shmlock_user_lock); | |
616 | free_uid(user); | |
617 | } |