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 | ||
7798330a LT |
138 | static inline int stack_guard_page(struct vm_area_struct *vma, unsigned long addr) |
139 | { | |
140 | return (vma->vm_flags & VM_GROWSDOWN) && | |
141 | (vma->vm_start == addr) && | |
142 | !vma_stack_continue(vma->vm_prev, addr); | |
143 | } | |
144 | ||
ba470de4 | 145 | /** |
408e82b7 | 146 | * __mlock_vma_pages_range() - mlock a range of pages in the vma. |
ba470de4 RR |
147 | * @vma: target vma |
148 | * @start: start address | |
149 | * @end: end address | |
ba470de4 | 150 | * |
408e82b7 | 151 | * This takes care of making the pages present too. |
b291f000 | 152 | * |
ba470de4 | 153 | * return 0 on success, negative error code on error. |
b291f000 | 154 | * |
ba470de4 | 155 | * vma->vm_mm->mmap_sem must be held for at least read. |
b291f000 | 156 | */ |
ba470de4 | 157 | static long __mlock_vma_pages_range(struct vm_area_struct *vma, |
53a7706d ML |
158 | unsigned long start, unsigned long end, |
159 | int *nonblocking) | |
b291f000 NP |
160 | { |
161 | struct mm_struct *mm = vma->vm_mm; | |
162 | unsigned long addr = start; | |
b291f000 | 163 | int nr_pages = (end - start) / PAGE_SIZE; |
408e82b7 | 164 | int gup_flags; |
ba470de4 RR |
165 | |
166 | VM_BUG_ON(start & ~PAGE_MASK); | |
167 | VM_BUG_ON(end & ~PAGE_MASK); | |
168 | VM_BUG_ON(start < vma->vm_start); | |
169 | VM_BUG_ON(end > vma->vm_end); | |
408e82b7 | 170 | VM_BUG_ON(!rwsem_is_locked(&mm->mmap_sem)); |
b291f000 | 171 | |
5fdb2002 | 172 | gup_flags = FOLL_TOUCH; |
5ecfda04 ML |
173 | /* |
174 | * We want to touch writable mappings with a write fault in order | |
175 | * to break COW, except for shared mappings because these don't COW | |
176 | * and we would not want to dirty them for nothing. | |
177 | */ | |
178 | if ((vma->vm_flags & (VM_WRITE | VM_SHARED)) == VM_WRITE) | |
58fa879e | 179 | gup_flags |= FOLL_WRITE; |
b291f000 | 180 | |
fdf4c587 ML |
181 | /* |
182 | * We want mlock to succeed for regions that have any permissions | |
183 | * other than PROT_NONE. | |
184 | */ | |
185 | if (vma->vm_flags & (VM_READ | VM_WRITE | VM_EXEC)) | |
186 | gup_flags |= FOLL_FORCE; | |
187 | ||
5fdb2002 ML |
188 | if (vma->vm_flags & VM_LOCKED) |
189 | gup_flags |= FOLL_MLOCK; | |
190 | ||
d7824370 | 191 | /* We don't try to access the guard page of a stack vma */ |
7798330a LT |
192 | if (stack_guard_page(vma, start)) { |
193 | addr += PAGE_SIZE; | |
194 | nr_pages--; | |
d7824370 LT |
195 | } |
196 | ||
53a7706d ML |
197 | return __get_user_pages(current, mm, addr, nr_pages, gup_flags, |
198 | NULL, NULL, nonblocking); | |
9978ad58 LS |
199 | } |
200 | ||
201 | /* | |
202 | * convert get_user_pages() return value to posix mlock() error | |
203 | */ | |
204 | static int __mlock_posix_error_return(long retval) | |
205 | { | |
206 | if (retval == -EFAULT) | |
207 | retval = -ENOMEM; | |
208 | else if (retval == -ENOMEM) | |
209 | retval = -EAGAIN; | |
210 | return retval; | |
b291f000 NP |
211 | } |
212 | ||
ba470de4 RR |
213 | /** |
214 | * mlock_vma_pages_range() - mlock pages in specified vma range. | |
215 | * @vma - the vma containing the specfied address range | |
216 | * @start - starting address in @vma to mlock | |
217 | * @end - end address [+1] in @vma to mlock | |
218 | * | |
219 | * For mmap()/mremap()/expansion of mlocked vma. | |
220 | * | |
221 | * return 0 on success for "normal" vmas. | |
222 | * | |
223 | * return number of pages [> 0] to be removed from locked_vm on success | |
224 | * of "special" vmas. | |
b291f000 | 225 | */ |
ba470de4 | 226 | long mlock_vma_pages_range(struct vm_area_struct *vma, |
b291f000 NP |
227 | unsigned long start, unsigned long end) |
228 | { | |
229 | int nr_pages = (end - start) / PAGE_SIZE; | |
230 | BUG_ON(!(vma->vm_flags & VM_LOCKED)); | |
231 | ||
232 | /* | |
233 | * filter unlockable vmas | |
234 | */ | |
235 | if (vma->vm_flags & (VM_IO | VM_PFNMAP)) | |
236 | goto no_mlock; | |
237 | ||
238 | if (!((vma->vm_flags & (VM_DONTEXPAND | VM_RESERVED)) || | |
239 | is_vm_hugetlb_page(vma) || | |
8edb08ca | 240 | vma == get_gate_vma(current))) { |
8edb08ca | 241 | |
53a7706d | 242 | __mlock_vma_pages_range(vma, start, end, NULL); |
d5b56233 HD |
243 | |
244 | /* Hide errors from mmap() and other callers */ | |
245 | return 0; | |
8edb08ca | 246 | } |
b291f000 NP |
247 | |
248 | /* | |
249 | * User mapped kernel pages or huge pages: | |
250 | * make these pages present to populate the ptes, but | |
251 | * fall thru' to reset VM_LOCKED--no need to unlock, and | |
252 | * return nr_pages so these don't get counted against task's | |
253 | * locked limit. huge pages are already counted against | |
254 | * locked vm limit. | |
255 | */ | |
256 | make_pages_present(start, end); | |
257 | ||
258 | no_mlock: | |
259 | vma->vm_flags &= ~VM_LOCKED; /* and don't come back! */ | |
ba470de4 | 260 | return nr_pages; /* error or pages NOT mlocked */ |
b291f000 NP |
261 | } |
262 | ||
b291f000 | 263 | /* |
ba470de4 RR |
264 | * munlock_vma_pages_range() - munlock all pages in the vma range.' |
265 | * @vma - vma containing range to be munlock()ed. | |
266 | * @start - start address in @vma of the range | |
267 | * @end - end of range in @vma. | |
268 | * | |
269 | * For mremap(), munmap() and exit(). | |
270 | * | |
271 | * Called with @vma VM_LOCKED. | |
272 | * | |
273 | * Returns with VM_LOCKED cleared. Callers must be prepared to | |
274 | * deal with this. | |
275 | * | |
276 | * We don't save and restore VM_LOCKED here because pages are | |
277 | * still on lru. In unmap path, pages might be scanned by reclaim | |
278 | * and re-mlocked by try_to_{munlock|unmap} before we unmap and | |
279 | * free them. This will result in freeing mlocked pages. | |
b291f000 | 280 | */ |
ba470de4 | 281 | void munlock_vma_pages_range(struct vm_area_struct *vma, |
408e82b7 | 282 | unsigned long start, unsigned long end) |
b291f000 | 283 | { |
408e82b7 HD |
284 | unsigned long addr; |
285 | ||
286 | lru_add_drain(); | |
b291f000 | 287 | vma->vm_flags &= ~VM_LOCKED; |
408e82b7 HD |
288 | |
289 | for (addr = start; addr < end; addr += PAGE_SIZE) { | |
6e919717 HD |
290 | struct page *page; |
291 | /* | |
292 | * Although FOLL_DUMP is intended for get_dump_page(), | |
293 | * it just so happens that its special treatment of the | |
294 | * ZERO_PAGE (returning an error instead of doing get_page) | |
295 | * suits munlock very well (and if somehow an abnormal page | |
296 | * has sneaked into the range, we won't oops here: great). | |
297 | */ | |
298 | page = follow_page(vma, addr, FOLL_GET | FOLL_DUMP); | |
299 | if (page && !IS_ERR(page)) { | |
408e82b7 | 300 | lock_page(page); |
6e919717 HD |
301 | /* |
302 | * Like in __mlock_vma_pages_range(), | |
303 | * because we lock page here and migration is | |
304 | * blocked by the elevated reference, we need | |
305 | * only check for file-cache page truncation. | |
306 | */ | |
408e82b7 HD |
307 | if (page->mapping) |
308 | munlock_vma_page(page); | |
309 | unlock_page(page); | |
310 | put_page(page); | |
311 | } | |
312 | cond_resched(); | |
313 | } | |
b291f000 NP |
314 | } |
315 | ||
316 | /* | |
317 | * mlock_fixup - handle mlock[all]/munlock[all] requests. | |
318 | * | |
319 | * Filters out "special" vmas -- VM_LOCKED never gets set for these, and | |
320 | * munlock is a no-op. However, for some special vmas, we go ahead and | |
321 | * populate the ptes via make_pages_present(). | |
322 | * | |
323 | * For vmas that pass the filters, merge/split as appropriate. | |
324 | */ | |
1da177e4 LT |
325 | static int mlock_fixup(struct vm_area_struct *vma, struct vm_area_struct **prev, |
326 | unsigned long start, unsigned long end, unsigned int newflags) | |
327 | { | |
b291f000 | 328 | struct mm_struct *mm = vma->vm_mm; |
1da177e4 | 329 | pgoff_t pgoff; |
b291f000 | 330 | int nr_pages; |
1da177e4 | 331 | int ret = 0; |
b291f000 | 332 | int lock = newflags & VM_LOCKED; |
1da177e4 | 333 | |
fed067da ML |
334 | if (newflags == vma->vm_flags || (vma->vm_flags & VM_SPECIAL) || |
335 | is_vm_hugetlb_page(vma) || vma == get_gate_vma(current)) | |
b291f000 NP |
336 | goto out; /* don't set VM_LOCKED, don't count */ |
337 | ||
1da177e4 LT |
338 | pgoff = vma->vm_pgoff + ((start - vma->vm_start) >> PAGE_SHIFT); |
339 | *prev = vma_merge(mm, *prev, start, end, newflags, vma->anon_vma, | |
340 | vma->vm_file, pgoff, vma_policy(vma)); | |
341 | if (*prev) { | |
342 | vma = *prev; | |
343 | goto success; | |
344 | } | |
345 | ||
1da177e4 LT |
346 | if (start != vma->vm_start) { |
347 | ret = split_vma(mm, vma, start, 1); | |
348 | if (ret) | |
349 | goto out; | |
350 | } | |
351 | ||
352 | if (end != vma->vm_end) { | |
353 | ret = split_vma(mm, vma, end, 0); | |
354 | if (ret) | |
355 | goto out; | |
356 | } | |
357 | ||
358 | success: | |
b291f000 NP |
359 | /* |
360 | * Keep track of amount of locked VM. | |
361 | */ | |
362 | nr_pages = (end - start) >> PAGE_SHIFT; | |
363 | if (!lock) | |
364 | nr_pages = -nr_pages; | |
365 | mm->locked_vm += nr_pages; | |
366 | ||
1da177e4 LT |
367 | /* |
368 | * vm_flags is protected by the mmap_sem held in write mode. | |
369 | * It's okay if try_to_unmap_one unmaps a page just after we | |
b291f000 | 370 | * set VM_LOCKED, __mlock_vma_pages_range will bring it back. |
1da177e4 | 371 | */ |
1da177e4 | 372 | |
fed067da | 373 | if (lock) |
408e82b7 | 374 | vma->vm_flags = newflags; |
fed067da | 375 | else |
408e82b7 | 376 | munlock_vma_pages_range(vma, start, end); |
1da177e4 | 377 | |
1da177e4 | 378 | out: |
b291f000 | 379 | *prev = vma; |
1da177e4 LT |
380 | return ret; |
381 | } | |
382 | ||
383 | static int do_mlock(unsigned long start, size_t len, int on) | |
384 | { | |
385 | unsigned long nstart, end, tmp; | |
386 | struct vm_area_struct * vma, * prev; | |
387 | int error; | |
388 | ||
fed067da ML |
389 | VM_BUG_ON(start & ~PAGE_MASK); |
390 | VM_BUG_ON(len != PAGE_ALIGN(len)); | |
1da177e4 LT |
391 | end = start + len; |
392 | if (end < start) | |
393 | return -EINVAL; | |
394 | if (end == start) | |
395 | return 0; | |
396 | vma = find_vma_prev(current->mm, start, &prev); | |
397 | if (!vma || vma->vm_start > start) | |
398 | return -ENOMEM; | |
399 | ||
400 | if (start > vma->vm_start) | |
401 | prev = vma; | |
402 | ||
403 | for (nstart = start ; ; ) { | |
404 | unsigned int newflags; | |
405 | ||
406 | /* Here we know that vma->vm_start <= nstart < vma->vm_end. */ | |
407 | ||
408 | newflags = vma->vm_flags | VM_LOCKED; | |
409 | if (!on) | |
410 | newflags &= ~VM_LOCKED; | |
411 | ||
412 | tmp = vma->vm_end; | |
413 | if (tmp > end) | |
414 | tmp = end; | |
415 | error = mlock_fixup(vma, &prev, nstart, tmp, newflags); | |
416 | if (error) | |
417 | break; | |
418 | nstart = tmp; | |
419 | if (nstart < prev->vm_end) | |
420 | nstart = prev->vm_end; | |
421 | if (nstart >= end) | |
422 | break; | |
423 | ||
424 | vma = prev->vm_next; | |
425 | if (!vma || vma->vm_start != nstart) { | |
426 | error = -ENOMEM; | |
427 | break; | |
428 | } | |
429 | } | |
430 | return error; | |
431 | } | |
432 | ||
fed067da ML |
433 | static int do_mlock_pages(unsigned long start, size_t len, int ignore_errors) |
434 | { | |
435 | struct mm_struct *mm = current->mm; | |
436 | unsigned long end, nstart, nend; | |
437 | struct vm_area_struct *vma = NULL; | |
53a7706d | 438 | int locked = 0; |
fed067da ML |
439 | int ret = 0; |
440 | ||
441 | VM_BUG_ON(start & ~PAGE_MASK); | |
442 | VM_BUG_ON(len != PAGE_ALIGN(len)); | |
443 | end = start + len; | |
444 | ||
fed067da ML |
445 | for (nstart = start; nstart < end; nstart = nend) { |
446 | /* | |
447 | * We want to fault in pages for [nstart; end) address range. | |
448 | * Find first corresponding VMA. | |
449 | */ | |
53a7706d ML |
450 | if (!locked) { |
451 | locked = 1; | |
452 | down_read(&mm->mmap_sem); | |
fed067da | 453 | vma = find_vma(mm, nstart); |
53a7706d | 454 | } else if (nstart >= vma->vm_end) |
fed067da ML |
455 | vma = vma->vm_next; |
456 | if (!vma || vma->vm_start >= end) | |
457 | break; | |
458 | /* | |
459 | * Set [nstart; nend) to intersection of desired address | |
460 | * range with the first VMA. Also, skip undesirable VMA types. | |
461 | */ | |
462 | nend = min(end, vma->vm_end); | |
463 | if (vma->vm_flags & (VM_IO | VM_PFNMAP)) | |
464 | continue; | |
465 | if (nstart < vma->vm_start) | |
466 | nstart = vma->vm_start; | |
467 | /* | |
53a7706d ML |
468 | * Now fault in a range of pages. __mlock_vma_pages_range() |
469 | * double checks the vma flags, so that it won't mlock pages | |
470 | * if the vma was already munlocked. | |
fed067da | 471 | */ |
53a7706d ML |
472 | ret = __mlock_vma_pages_range(vma, nstart, nend, &locked); |
473 | if (ret < 0) { | |
474 | if (ignore_errors) { | |
475 | ret = 0; | |
476 | continue; /* continue at next VMA */ | |
477 | } | |
5fdb2002 ML |
478 | ret = __mlock_posix_error_return(ret); |
479 | break; | |
480 | } | |
53a7706d ML |
481 | nend = nstart + ret * PAGE_SIZE; |
482 | ret = 0; | |
fed067da | 483 | } |
53a7706d ML |
484 | if (locked) |
485 | up_read(&mm->mmap_sem); | |
fed067da ML |
486 | return ret; /* 0 or negative error code */ |
487 | } | |
488 | ||
6a6160a7 | 489 | SYSCALL_DEFINE2(mlock, unsigned long, start, size_t, len) |
1da177e4 LT |
490 | { |
491 | unsigned long locked; | |
492 | unsigned long lock_limit; | |
493 | int error = -ENOMEM; | |
494 | ||
495 | if (!can_do_mlock()) | |
496 | return -EPERM; | |
497 | ||
8891d6da KM |
498 | lru_add_drain_all(); /* flush pagevec */ |
499 | ||
1da177e4 LT |
500 | down_write(¤t->mm->mmap_sem); |
501 | len = PAGE_ALIGN(len + (start & ~PAGE_MASK)); | |
502 | start &= PAGE_MASK; | |
503 | ||
504 | locked = len >> PAGE_SHIFT; | |
505 | locked += current->mm->locked_vm; | |
506 | ||
59e99e5b | 507 | lock_limit = rlimit(RLIMIT_MEMLOCK); |
1da177e4 LT |
508 | lock_limit >>= PAGE_SHIFT; |
509 | ||
510 | /* check against resource limits */ | |
511 | if ((locked <= lock_limit) || capable(CAP_IPC_LOCK)) | |
512 | error = do_mlock(start, len, 1); | |
513 | up_write(¤t->mm->mmap_sem); | |
fed067da ML |
514 | if (!error) |
515 | error = do_mlock_pages(start, len, 0); | |
1da177e4 LT |
516 | return error; |
517 | } | |
518 | ||
6a6160a7 | 519 | SYSCALL_DEFINE2(munlock, unsigned long, start, size_t, len) |
1da177e4 LT |
520 | { |
521 | int ret; | |
522 | ||
523 | down_write(¤t->mm->mmap_sem); | |
524 | len = PAGE_ALIGN(len + (start & ~PAGE_MASK)); | |
525 | start &= PAGE_MASK; | |
526 | ret = do_mlock(start, len, 0); | |
527 | up_write(¤t->mm->mmap_sem); | |
528 | return ret; | |
529 | } | |
530 | ||
531 | static int do_mlockall(int flags) | |
532 | { | |
533 | struct vm_area_struct * vma, * prev = NULL; | |
534 | unsigned int def_flags = 0; | |
535 | ||
536 | if (flags & MCL_FUTURE) | |
537 | def_flags = VM_LOCKED; | |
538 | current->mm->def_flags = def_flags; | |
539 | if (flags == MCL_FUTURE) | |
540 | goto out; | |
541 | ||
542 | for (vma = current->mm->mmap; vma ; vma = prev->vm_next) { | |
543 | unsigned int newflags; | |
544 | ||
545 | newflags = vma->vm_flags | VM_LOCKED; | |
546 | if (!(flags & MCL_CURRENT)) | |
547 | newflags &= ~VM_LOCKED; | |
548 | ||
549 | /* Ignore errors */ | |
550 | mlock_fixup(vma, &prev, vma->vm_start, vma->vm_end, newflags); | |
551 | } | |
552 | out: | |
553 | return 0; | |
554 | } | |
555 | ||
3480b257 | 556 | SYSCALL_DEFINE1(mlockall, int, flags) |
1da177e4 LT |
557 | { |
558 | unsigned long lock_limit; | |
559 | int ret = -EINVAL; | |
560 | ||
561 | if (!flags || (flags & ~(MCL_CURRENT | MCL_FUTURE))) | |
562 | goto out; | |
563 | ||
564 | ret = -EPERM; | |
565 | if (!can_do_mlock()) | |
566 | goto out; | |
567 | ||
8891d6da KM |
568 | lru_add_drain_all(); /* flush pagevec */ |
569 | ||
1da177e4 LT |
570 | down_write(¤t->mm->mmap_sem); |
571 | ||
59e99e5b | 572 | lock_limit = rlimit(RLIMIT_MEMLOCK); |
1da177e4 LT |
573 | lock_limit >>= PAGE_SHIFT; |
574 | ||
575 | ret = -ENOMEM; | |
576 | if (!(flags & MCL_CURRENT) || (current->mm->total_vm <= lock_limit) || | |
577 | capable(CAP_IPC_LOCK)) | |
578 | ret = do_mlockall(flags); | |
579 | up_write(¤t->mm->mmap_sem); | |
fed067da ML |
580 | if (!ret && (flags & MCL_CURRENT)) { |
581 | /* Ignore errors */ | |
582 | do_mlock_pages(0, TASK_SIZE, 1); | |
583 | } | |
1da177e4 LT |
584 | out: |
585 | return ret; | |
586 | } | |
587 | ||
3480b257 | 588 | SYSCALL_DEFINE0(munlockall) |
1da177e4 LT |
589 | { |
590 | int ret; | |
591 | ||
592 | down_write(¤t->mm->mmap_sem); | |
593 | ret = do_mlockall(0); | |
594 | up_write(¤t->mm->mmap_sem); | |
595 | return ret; | |
596 | } | |
597 | ||
598 | /* | |
599 | * Objects with different lifetime than processes (SHM_LOCK and SHM_HUGETLB | |
600 | * shm segments) get accounted against the user_struct instead. | |
601 | */ | |
602 | static DEFINE_SPINLOCK(shmlock_user_lock); | |
603 | ||
604 | int user_shm_lock(size_t size, struct user_struct *user) | |
605 | { | |
606 | unsigned long lock_limit, locked; | |
607 | int allowed = 0; | |
608 | ||
609 | locked = (size + PAGE_SIZE - 1) >> PAGE_SHIFT; | |
59e99e5b | 610 | lock_limit = rlimit(RLIMIT_MEMLOCK); |
5ed44a40 HB |
611 | if (lock_limit == RLIM_INFINITY) |
612 | allowed = 1; | |
1da177e4 LT |
613 | lock_limit >>= PAGE_SHIFT; |
614 | spin_lock(&shmlock_user_lock); | |
5ed44a40 HB |
615 | if (!allowed && |
616 | locked + user->locked_shm > lock_limit && !capable(CAP_IPC_LOCK)) | |
1da177e4 LT |
617 | goto out; |
618 | get_uid(user); | |
619 | user->locked_shm += locked; | |
620 | allowed = 1; | |
621 | out: | |
622 | spin_unlock(&shmlock_user_lock); | |
623 | return allowed; | |
624 | } | |
625 | ||
626 | void user_shm_unlock(size_t size, struct user_struct *user) | |
627 | { | |
628 | spin_lock(&shmlock_user_lock); | |
629 | user->locked_shm -= (size + PAGE_SIZE - 1) >> PAGE_SHIFT; | |
630 | spin_unlock(&shmlock_user_lock); | |
631 | free_uid(user); | |
632 | } |