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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; | |
28 | if (current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur != 0) | |
29 | return 1; | |
30 | return 0; | |
31 | } | |
32 | EXPORT_SYMBOL(can_do_mlock); | |
1da177e4 | 33 | |
b291f000 NP |
34 | #ifdef CONFIG_UNEVICTABLE_LRU |
35 | /* | |
36 | * Mlocked pages are marked with PageMlocked() flag for efficient testing | |
37 | * in vmscan and, possibly, the fault path; and to support semi-accurate | |
38 | * statistics. | |
39 | * | |
40 | * An mlocked page [PageMlocked(page)] is unevictable. As such, it will | |
41 | * be placed on the LRU "unevictable" list, rather than the [in]active lists. | |
42 | * The unevictable list is an LRU sibling list to the [in]active lists. | |
43 | * PageUnevictable is set to indicate the unevictable state. | |
44 | * | |
45 | * When lazy mlocking via vmscan, it is important to ensure that the | |
46 | * vma's VM_LOCKED status is not concurrently being modified, otherwise we | |
47 | * may have mlocked a page that is being munlocked. So lazy mlock must take | |
48 | * the mmap_sem for read, and verify that the vma really is locked | |
49 | * (see mm/rmap.c). | |
50 | */ | |
51 | ||
52 | /* | |
53 | * LRU accounting for clear_page_mlock() | |
54 | */ | |
55 | void __clear_page_mlock(struct page *page) | |
56 | { | |
57 | VM_BUG_ON(!PageLocked(page)); | |
58 | ||
59 | if (!page->mapping) { /* truncated ? */ | |
60 | return; | |
61 | } | |
62 | ||
5344b7e6 NP |
63 | dec_zone_page_state(page, NR_MLOCK); |
64 | count_vm_event(UNEVICTABLE_PGCLEARED); | |
b291f000 NP |
65 | if (!isolate_lru_page(page)) { |
66 | putback_lru_page(page); | |
67 | } else { | |
68 | /* | |
8891d6da | 69 | * We lost the race. the page already moved to evictable list. |
b291f000 | 70 | */ |
8891d6da | 71 | if (PageUnevictable(page)) |
5344b7e6 | 72 | count_vm_event(UNEVICTABLE_PGSTRANDED); |
b291f000 NP |
73 | } |
74 | } | |
75 | ||
76 | /* | |
77 | * Mark page as mlocked if not already. | |
78 | * If page on LRU, isolate and putback to move to unevictable list. | |
79 | */ | |
80 | void mlock_vma_page(struct page *page) | |
81 | { | |
82 | BUG_ON(!PageLocked(page)); | |
83 | ||
5344b7e6 NP |
84 | if (!TestSetPageMlocked(page)) { |
85 | inc_zone_page_state(page, NR_MLOCK); | |
86 | count_vm_event(UNEVICTABLE_PGMLOCKED); | |
87 | if (!isolate_lru_page(page)) | |
88 | putback_lru_page(page); | |
89 | } | |
b291f000 NP |
90 | } |
91 | ||
92 | /* | |
93 | * called from munlock()/munmap() path with page supposedly on the LRU. | |
94 | * | |
95 | * Note: unlike mlock_vma_page(), we can't just clear the PageMlocked | |
96 | * [in try_to_munlock()] and then attempt to isolate the page. We must | |
97 | * isolate the page to keep others from messing with its unevictable | |
98 | * and mlocked state while trying to munlock. However, we pre-clear the | |
99 | * mlocked state anyway as we might lose the isolation race and we might | |
100 | * not get another chance to clear PageMlocked. If we successfully | |
101 | * isolate the page and try_to_munlock() detects other VM_LOCKED vmas | |
102 | * mapping the page, it will restore the PageMlocked state, unless the page | |
103 | * is mapped in a non-linear vma. So, we go ahead and SetPageMlocked(), | |
104 | * perhaps redundantly. | |
105 | * If we lose the isolation race, and the page is mapped by other VM_LOCKED | |
106 | * vmas, we'll detect this in vmscan--via try_to_munlock() or try_to_unmap() | |
107 | * either of which will restore the PageMlocked state by calling | |
108 | * mlock_vma_page() above, if it can grab the vma's mmap sem. | |
109 | */ | |
110 | static void munlock_vma_page(struct page *page) | |
111 | { | |
112 | BUG_ON(!PageLocked(page)); | |
113 | ||
5344b7e6 NP |
114 | if (TestClearPageMlocked(page)) { |
115 | dec_zone_page_state(page, NR_MLOCK); | |
116 | if (!isolate_lru_page(page)) { | |
117 | int ret = try_to_munlock(page); | |
118 | /* | |
119 | * did try_to_unlock() succeed or punt? | |
120 | */ | |
121 | if (ret == SWAP_SUCCESS || ret == SWAP_AGAIN) | |
122 | count_vm_event(UNEVICTABLE_PGMUNLOCKED); | |
123 | ||
124 | putback_lru_page(page); | |
125 | } else { | |
126 | /* | |
127 | * We lost the race. let try_to_unmap() deal | |
128 | * with it. At least we get the page state and | |
129 | * mlock stats right. However, page is still on | |
130 | * the noreclaim list. We'll fix that up when | |
131 | * the page is eventually freed or we scan the | |
132 | * noreclaim list. | |
133 | */ | |
134 | if (PageUnevictable(page)) | |
135 | count_vm_event(UNEVICTABLE_PGSTRANDED); | |
136 | else | |
137 | count_vm_event(UNEVICTABLE_PGMUNLOCKED); | |
138 | } | |
b291f000 NP |
139 | } |
140 | } | |
141 | ||
ba470de4 RR |
142 | /** |
143 | * __mlock_vma_pages_range() - mlock/munlock a range of pages in the vma. | |
144 | * @vma: target vma | |
145 | * @start: start address | |
146 | * @end: end address | |
147 | * @mlock: 0 indicate munlock, otherwise mlock. | |
148 | * | |
149 | * If @mlock == 0, unlock an mlocked range; | |
150 | * else mlock the range of pages. This takes care of making the pages present , | |
151 | * 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 RR |
157 | static long __mlock_vma_pages_range(struct vm_area_struct *vma, |
158 | unsigned long start, unsigned long end, | |
159 | int mlock) | |
b291f000 NP |
160 | { |
161 | struct mm_struct *mm = vma->vm_mm; | |
162 | unsigned long addr = start; | |
163 | struct page *pages[16]; /* 16 gives a reasonable batch */ | |
b291f000 | 164 | int nr_pages = (end - start) / PAGE_SIZE; |
72eb8c67 | 165 | int ret = 0; |
ba470de4 RR |
166 | int gup_flags = 0; |
167 | ||
168 | VM_BUG_ON(start & ~PAGE_MASK); | |
169 | VM_BUG_ON(end & ~PAGE_MASK); | |
170 | VM_BUG_ON(start < vma->vm_start); | |
171 | VM_BUG_ON(end > vma->vm_end); | |
172 | VM_BUG_ON((!rwsem_is_locked(&mm->mmap_sem)) && | |
173 | (atomic_read(&mm->mm_users) != 0)); | |
174 | ||
175 | /* | |
176 | * mlock: don't page populate if page has PROT_NONE permission. | |
177 | * munlock: the pages always do munlock althrough | |
178 | * its has PROT_NONE permission. | |
179 | */ | |
180 | if (!mlock) | |
181 | gup_flags |= GUP_FLAGS_IGNORE_VMA_PERMISSIONS; | |
b291f000 | 182 | |
ba470de4 RR |
183 | if (vma->vm_flags & VM_WRITE) |
184 | gup_flags |= GUP_FLAGS_WRITE; | |
b291f000 | 185 | |
b291f000 NP |
186 | while (nr_pages > 0) { |
187 | int i; | |
188 | ||
189 | cond_resched(); | |
190 | ||
191 | /* | |
192 | * get_user_pages makes pages present if we are | |
193 | * setting mlock. and this extra reference count will | |
194 | * disable migration of this page. However, page may | |
195 | * still be truncated out from under us. | |
196 | */ | |
ba470de4 | 197 | ret = __get_user_pages(current, mm, addr, |
b291f000 | 198 | min_t(int, nr_pages, ARRAY_SIZE(pages)), |
ba470de4 | 199 | gup_flags, pages, NULL); |
b291f000 NP |
200 | /* |
201 | * This can happen for, e.g., VM_NONLINEAR regions before | |
202 | * a page has been allocated and mapped at a given offset, | |
203 | * or for addresses that map beyond end of a file. | |
204 | * We'll mlock the the pages if/when they get faulted in. | |
205 | */ | |
206 | if (ret < 0) | |
207 | break; | |
208 | if (ret == 0) { | |
209 | /* | |
210 | * We know the vma is there, so the only time | |
211 | * we cannot get a single page should be an | |
212 | * error (ret < 0) case. | |
213 | */ | |
214 | WARN_ON(1); | |
215 | break; | |
216 | } | |
217 | ||
218 | lru_add_drain(); /* push cached pages to LRU */ | |
219 | ||
220 | for (i = 0; i < ret; i++) { | |
221 | struct page *page = pages[i]; | |
222 | ||
223 | lock_page(page); | |
224 | /* | |
225 | * Because we lock page here and migration is blocked | |
226 | * by the elevated reference, we need only check for | |
227 | * page truncation (file-cache only). | |
228 | */ | |
ba470de4 RR |
229 | if (page->mapping) { |
230 | if (mlock) | |
231 | mlock_vma_page(page); | |
232 | else | |
233 | munlock_vma_page(page); | |
234 | } | |
b291f000 NP |
235 | unlock_page(page); |
236 | put_page(page); /* ref from get_user_pages() */ | |
237 | ||
238 | /* | |
239 | * here we assume that get_user_pages() has given us | |
240 | * a list of virtually contiguous pages. | |
241 | */ | |
242 | addr += PAGE_SIZE; /* for next get_user_pages() */ | |
243 | nr_pages--; | |
244 | } | |
9978ad58 | 245 | ret = 0; |
b291f000 NP |
246 | } |
247 | ||
9978ad58 LS |
248 | return ret; /* count entire vma as locked_vm */ |
249 | } | |
250 | ||
251 | /* | |
252 | * convert get_user_pages() return value to posix mlock() error | |
253 | */ | |
254 | static int __mlock_posix_error_return(long retval) | |
255 | { | |
256 | if (retval == -EFAULT) | |
257 | retval = -ENOMEM; | |
258 | else if (retval == -ENOMEM) | |
259 | retval = -EAGAIN; | |
260 | return retval; | |
b291f000 NP |
261 | } |
262 | ||
b291f000 NP |
263 | #else /* CONFIG_UNEVICTABLE_LRU */ |
264 | ||
265 | /* | |
266 | * Just make pages present if VM_LOCKED. No-op if unlocking. | |
267 | */ | |
ba470de4 RR |
268 | static long __mlock_vma_pages_range(struct vm_area_struct *vma, |
269 | unsigned long start, unsigned long end, | |
270 | int mlock) | |
b291f000 | 271 | { |
ba470de4 | 272 | if (mlock && (vma->vm_flags & VM_LOCKED)) |
9978ad58 LS |
273 | return make_pages_present(start, end); |
274 | return 0; | |
275 | } | |
276 | ||
277 | static inline int __mlock_posix_error_return(long retval) | |
278 | { | |
b291f000 NP |
279 | return 0; |
280 | } | |
9978ad58 | 281 | |
b291f000 NP |
282 | #endif /* CONFIG_UNEVICTABLE_LRU */ |
283 | ||
ba470de4 RR |
284 | /** |
285 | * mlock_vma_pages_range() - mlock pages in specified vma range. | |
286 | * @vma - the vma containing the specfied address range | |
287 | * @start - starting address in @vma to mlock | |
288 | * @end - end address [+1] in @vma to mlock | |
289 | * | |
290 | * For mmap()/mremap()/expansion of mlocked vma. | |
291 | * | |
292 | * return 0 on success for "normal" vmas. | |
293 | * | |
294 | * return number of pages [> 0] to be removed from locked_vm on success | |
295 | * of "special" vmas. | |
296 | * | |
297 | * return negative error if vma spanning @start-@range disappears while | |
298 | * mmap semaphore is dropped. Unlikely? | |
b291f000 | 299 | */ |
ba470de4 | 300 | long mlock_vma_pages_range(struct vm_area_struct *vma, |
b291f000 NP |
301 | unsigned long start, unsigned long end) |
302 | { | |
8edb08ca | 303 | struct mm_struct *mm = vma->vm_mm; |
b291f000 NP |
304 | int nr_pages = (end - start) / PAGE_SIZE; |
305 | BUG_ON(!(vma->vm_flags & VM_LOCKED)); | |
306 | ||
307 | /* | |
308 | * filter unlockable vmas | |
309 | */ | |
310 | if (vma->vm_flags & (VM_IO | VM_PFNMAP)) | |
311 | goto no_mlock; | |
312 | ||
313 | if (!((vma->vm_flags & (VM_DONTEXPAND | VM_RESERVED)) || | |
314 | is_vm_hugetlb_page(vma) || | |
8edb08ca | 315 | vma == get_gate_vma(current))) { |
ba470de4 | 316 | long error; |
8edb08ca | 317 | downgrade_write(&mm->mmap_sem); |
ba470de4 RR |
318 | |
319 | error = __mlock_vma_pages_range(vma, start, end, 1); | |
8edb08ca LS |
320 | |
321 | up_read(&mm->mmap_sem); | |
322 | /* vma can change or disappear */ | |
323 | down_write(&mm->mmap_sem); | |
324 | vma = find_vma(mm, start); | |
325 | /* non-NULL vma must contain @start, but need to check @end */ | |
326 | if (!vma || end > vma->vm_end) | |
ba470de4 RR |
327 | return -ENOMEM; |
328 | ||
329 | return 0; /* hide other errors from mmap(), et al */ | |
8edb08ca | 330 | } |
b291f000 NP |
331 | |
332 | /* | |
333 | * User mapped kernel pages or huge pages: | |
334 | * make these pages present to populate the ptes, but | |
335 | * fall thru' to reset VM_LOCKED--no need to unlock, and | |
336 | * return nr_pages so these don't get counted against task's | |
337 | * locked limit. huge pages are already counted against | |
338 | * locked vm limit. | |
339 | */ | |
340 | make_pages_present(start, end); | |
341 | ||
342 | no_mlock: | |
343 | vma->vm_flags &= ~VM_LOCKED; /* and don't come back! */ | |
ba470de4 | 344 | return nr_pages; /* error or pages NOT mlocked */ |
b291f000 NP |
345 | } |
346 | ||
347 | ||
348 | /* | |
ba470de4 RR |
349 | * munlock_vma_pages_range() - munlock all pages in the vma range.' |
350 | * @vma - vma containing range to be munlock()ed. | |
351 | * @start - start address in @vma of the range | |
352 | * @end - end of range in @vma. | |
353 | * | |
354 | * For mremap(), munmap() and exit(). | |
355 | * | |
356 | * Called with @vma VM_LOCKED. | |
357 | * | |
358 | * Returns with VM_LOCKED cleared. Callers must be prepared to | |
359 | * deal with this. | |
360 | * | |
361 | * We don't save and restore VM_LOCKED here because pages are | |
362 | * still on lru. In unmap path, pages might be scanned by reclaim | |
363 | * and re-mlocked by try_to_{munlock|unmap} before we unmap and | |
364 | * free them. This will result in freeing mlocked pages. | |
b291f000 | 365 | */ |
ba470de4 RR |
366 | void munlock_vma_pages_range(struct vm_area_struct *vma, |
367 | unsigned long start, unsigned long end) | |
b291f000 NP |
368 | { |
369 | vma->vm_flags &= ~VM_LOCKED; | |
ba470de4 | 370 | __mlock_vma_pages_range(vma, start, end, 0); |
b291f000 NP |
371 | } |
372 | ||
373 | /* | |
374 | * mlock_fixup - handle mlock[all]/munlock[all] requests. | |
375 | * | |
376 | * Filters out "special" vmas -- VM_LOCKED never gets set for these, and | |
377 | * munlock is a no-op. However, for some special vmas, we go ahead and | |
378 | * populate the ptes via make_pages_present(). | |
379 | * | |
380 | * For vmas that pass the filters, merge/split as appropriate. | |
381 | */ | |
1da177e4 LT |
382 | static int mlock_fixup(struct vm_area_struct *vma, struct vm_area_struct **prev, |
383 | unsigned long start, unsigned long end, unsigned int newflags) | |
384 | { | |
b291f000 | 385 | struct mm_struct *mm = vma->vm_mm; |
1da177e4 | 386 | pgoff_t pgoff; |
b291f000 | 387 | int nr_pages; |
1da177e4 | 388 | int ret = 0; |
b291f000 | 389 | int lock = newflags & VM_LOCKED; |
1da177e4 | 390 | |
b291f000 NP |
391 | if (newflags == vma->vm_flags || |
392 | (vma->vm_flags & (VM_IO | VM_PFNMAP))) | |
393 | goto out; /* don't set VM_LOCKED, don't count */ | |
394 | ||
395 | if ((vma->vm_flags & (VM_DONTEXPAND | VM_RESERVED)) || | |
396 | is_vm_hugetlb_page(vma) || | |
397 | vma == get_gate_vma(current)) { | |
398 | if (lock) | |
399 | make_pages_present(start, end); | |
400 | goto out; /* don't set VM_LOCKED, don't count */ | |
1da177e4 LT |
401 | } |
402 | ||
403 | pgoff = vma->vm_pgoff + ((start - vma->vm_start) >> PAGE_SHIFT); | |
404 | *prev = vma_merge(mm, *prev, start, end, newflags, vma->anon_vma, | |
405 | vma->vm_file, pgoff, vma_policy(vma)); | |
406 | if (*prev) { | |
407 | vma = *prev; | |
408 | goto success; | |
409 | } | |
410 | ||
1da177e4 LT |
411 | if (start != vma->vm_start) { |
412 | ret = split_vma(mm, vma, start, 1); | |
413 | if (ret) | |
414 | goto out; | |
415 | } | |
416 | ||
417 | if (end != vma->vm_end) { | |
418 | ret = split_vma(mm, vma, end, 0); | |
419 | if (ret) | |
420 | goto out; | |
421 | } | |
422 | ||
423 | success: | |
b291f000 NP |
424 | /* |
425 | * Keep track of amount of locked VM. | |
426 | */ | |
427 | nr_pages = (end - start) >> PAGE_SHIFT; | |
428 | if (!lock) | |
429 | nr_pages = -nr_pages; | |
430 | mm->locked_vm += nr_pages; | |
431 | ||
1da177e4 LT |
432 | /* |
433 | * vm_flags is protected by the mmap_sem held in write mode. | |
434 | * It's okay if try_to_unmap_one unmaps a page just after we | |
b291f000 | 435 | * set VM_LOCKED, __mlock_vma_pages_range will bring it back. |
1da177e4 LT |
436 | */ |
437 | vma->vm_flags = newflags; | |
438 | ||
b291f000 | 439 | if (lock) { |
8edb08ca LS |
440 | /* |
441 | * mmap_sem is currently held for write. Downgrade the write | |
442 | * lock to a read lock so that other faults, mmap scans, ... | |
443 | * while we fault in all pages. | |
444 | */ | |
445 | downgrade_write(&mm->mmap_sem); | |
446 | ||
ba470de4 | 447 | ret = __mlock_vma_pages_range(vma, start, end, 1); |
9978ad58 | 448 | |
8edb08ca LS |
449 | /* |
450 | * Need to reacquire mmap sem in write mode, as our callers | |
451 | * expect this. We have no support for atomically upgrading | |
452 | * a sem to write, so we need to check for ranges while sem | |
453 | * is unlocked. | |
454 | */ | |
455 | up_read(&mm->mmap_sem); | |
456 | /* vma can change or disappear */ | |
457 | down_write(&mm->mmap_sem); | |
458 | *prev = find_vma(mm, start); | |
459 | /* non-NULL *prev must contain @start, but need to check @end */ | |
460 | if (!(*prev) || end > (*prev)->vm_end) | |
ba470de4 | 461 | ret = -ENOMEM; |
9978ad58 LS |
462 | else if (ret > 0) { |
463 | mm->locked_vm -= ret; | |
464 | ret = 0; | |
465 | } else | |
466 | ret = __mlock_posix_error_return(ret); /* translate if needed */ | |
8edb08ca LS |
467 | } else { |
468 | /* | |
469 | * TODO: for unlocking, pages will already be resident, so | |
470 | * we don't need to wait for allocations/reclaim/pagein, ... | |
471 | * However, unlocking a very large region can still take a | |
472 | * while. Should we downgrade the semaphore for both lock | |
473 | * AND unlock ? | |
474 | */ | |
ba470de4 | 475 | __mlock_vma_pages_range(vma, start, end, 0); |
8edb08ca | 476 | } |
1da177e4 | 477 | |
1da177e4 | 478 | out: |
b291f000 | 479 | *prev = vma; |
1da177e4 LT |
480 | return ret; |
481 | } | |
482 | ||
483 | static int do_mlock(unsigned long start, size_t len, int on) | |
484 | { | |
485 | unsigned long nstart, end, tmp; | |
486 | struct vm_area_struct * vma, * prev; | |
487 | int error; | |
488 | ||
489 | len = PAGE_ALIGN(len); | |
490 | end = start + len; | |
491 | if (end < start) | |
492 | return -EINVAL; | |
493 | if (end == start) | |
494 | return 0; | |
495 | vma = find_vma_prev(current->mm, start, &prev); | |
496 | if (!vma || vma->vm_start > start) | |
497 | return -ENOMEM; | |
498 | ||
499 | if (start > vma->vm_start) | |
500 | prev = vma; | |
501 | ||
502 | for (nstart = start ; ; ) { | |
503 | unsigned int newflags; | |
504 | ||
505 | /* Here we know that vma->vm_start <= nstart < vma->vm_end. */ | |
506 | ||
507 | newflags = vma->vm_flags | VM_LOCKED; | |
508 | if (!on) | |
509 | newflags &= ~VM_LOCKED; | |
510 | ||
511 | tmp = vma->vm_end; | |
512 | if (tmp > end) | |
513 | tmp = end; | |
514 | error = mlock_fixup(vma, &prev, nstart, tmp, newflags); | |
515 | if (error) | |
516 | break; | |
517 | nstart = tmp; | |
518 | if (nstart < prev->vm_end) | |
519 | nstart = prev->vm_end; | |
520 | if (nstart >= end) | |
521 | break; | |
522 | ||
523 | vma = prev->vm_next; | |
524 | if (!vma || vma->vm_start != nstart) { | |
525 | error = -ENOMEM; | |
526 | break; | |
527 | } | |
528 | } | |
529 | return error; | |
530 | } | |
531 | ||
532 | asmlinkage long sys_mlock(unsigned long start, size_t len) | |
533 | { | |
534 | unsigned long locked; | |
535 | unsigned long lock_limit; | |
536 | int error = -ENOMEM; | |
537 | ||
538 | if (!can_do_mlock()) | |
539 | return -EPERM; | |
540 | ||
8891d6da KM |
541 | lru_add_drain_all(); /* flush pagevec */ |
542 | ||
1da177e4 LT |
543 | down_write(¤t->mm->mmap_sem); |
544 | len = PAGE_ALIGN(len + (start & ~PAGE_MASK)); | |
545 | start &= PAGE_MASK; | |
546 | ||
547 | locked = len >> PAGE_SHIFT; | |
548 | locked += current->mm->locked_vm; | |
549 | ||
550 | lock_limit = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur; | |
551 | lock_limit >>= PAGE_SHIFT; | |
552 | ||
553 | /* check against resource limits */ | |
554 | if ((locked <= lock_limit) || capable(CAP_IPC_LOCK)) | |
555 | error = do_mlock(start, len, 1); | |
556 | up_write(¤t->mm->mmap_sem); | |
557 | return error; | |
558 | } | |
559 | ||
560 | asmlinkage long sys_munlock(unsigned long start, size_t len) | |
561 | { | |
562 | int ret; | |
563 | ||
564 | down_write(¤t->mm->mmap_sem); | |
565 | len = PAGE_ALIGN(len + (start & ~PAGE_MASK)); | |
566 | start &= PAGE_MASK; | |
567 | ret = do_mlock(start, len, 0); | |
568 | up_write(¤t->mm->mmap_sem); | |
569 | return ret; | |
570 | } | |
571 | ||
572 | static int do_mlockall(int flags) | |
573 | { | |
574 | struct vm_area_struct * vma, * prev = NULL; | |
575 | unsigned int def_flags = 0; | |
576 | ||
577 | if (flags & MCL_FUTURE) | |
578 | def_flags = VM_LOCKED; | |
579 | current->mm->def_flags = def_flags; | |
580 | if (flags == MCL_FUTURE) | |
581 | goto out; | |
582 | ||
583 | for (vma = current->mm->mmap; vma ; vma = prev->vm_next) { | |
584 | unsigned int newflags; | |
585 | ||
586 | newflags = vma->vm_flags | VM_LOCKED; | |
587 | if (!(flags & MCL_CURRENT)) | |
588 | newflags &= ~VM_LOCKED; | |
589 | ||
590 | /* Ignore errors */ | |
591 | mlock_fixup(vma, &prev, vma->vm_start, vma->vm_end, newflags); | |
592 | } | |
593 | out: | |
594 | return 0; | |
595 | } | |
596 | ||
597 | asmlinkage long sys_mlockall(int flags) | |
598 | { | |
599 | unsigned long lock_limit; | |
600 | int ret = -EINVAL; | |
601 | ||
602 | if (!flags || (flags & ~(MCL_CURRENT | MCL_FUTURE))) | |
603 | goto out; | |
604 | ||
605 | ret = -EPERM; | |
606 | if (!can_do_mlock()) | |
607 | goto out; | |
608 | ||
8891d6da KM |
609 | lru_add_drain_all(); /* flush pagevec */ |
610 | ||
1da177e4 LT |
611 | down_write(¤t->mm->mmap_sem); |
612 | ||
613 | lock_limit = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur; | |
614 | lock_limit >>= PAGE_SHIFT; | |
615 | ||
616 | ret = -ENOMEM; | |
617 | if (!(flags & MCL_CURRENT) || (current->mm->total_vm <= lock_limit) || | |
618 | capable(CAP_IPC_LOCK)) | |
619 | ret = do_mlockall(flags); | |
620 | up_write(¤t->mm->mmap_sem); | |
621 | out: | |
622 | return ret; | |
623 | } | |
624 | ||
625 | asmlinkage long sys_munlockall(void) | |
626 | { | |
627 | int ret; | |
628 | ||
629 | down_write(¤t->mm->mmap_sem); | |
630 | ret = do_mlockall(0); | |
631 | up_write(¤t->mm->mmap_sem); | |
632 | return ret; | |
633 | } | |
634 | ||
635 | /* | |
636 | * Objects with different lifetime than processes (SHM_LOCK and SHM_HUGETLB | |
637 | * shm segments) get accounted against the user_struct instead. | |
638 | */ | |
639 | static DEFINE_SPINLOCK(shmlock_user_lock); | |
640 | ||
641 | int user_shm_lock(size_t size, struct user_struct *user) | |
642 | { | |
643 | unsigned long lock_limit, locked; | |
644 | int allowed = 0; | |
645 | ||
646 | locked = (size + PAGE_SIZE - 1) >> PAGE_SHIFT; | |
647 | lock_limit = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur; | |
5ed44a40 HB |
648 | if (lock_limit == RLIM_INFINITY) |
649 | allowed = 1; | |
1da177e4 LT |
650 | lock_limit >>= PAGE_SHIFT; |
651 | spin_lock(&shmlock_user_lock); | |
5ed44a40 HB |
652 | if (!allowed && |
653 | locked + user->locked_shm > lock_limit && !capable(CAP_IPC_LOCK)) | |
1da177e4 LT |
654 | goto out; |
655 | get_uid(user); | |
656 | user->locked_shm += locked; | |
657 | allowed = 1; | |
658 | out: | |
659 | spin_unlock(&shmlock_user_lock); | |
660 | return allowed; | |
661 | } | |
662 | ||
663 | void user_shm_unlock(size_t size, struct user_struct *user) | |
664 | { | |
665 | spin_lock(&shmlock_user_lock); | |
666 | user->locked_shm -= (size + PAGE_SIZE - 1) >> PAGE_SHIFT; | |
667 | spin_unlock(&shmlock_user_lock); | |
668 | free_uid(user); | |
669 | } | |
c5dee617 MM |
670 | |
671 | void *alloc_locked_buffer(size_t size) | |
672 | { | |
673 | unsigned long rlim, vm, pgsz; | |
674 | void *buffer = NULL; | |
675 | ||
676 | pgsz = PAGE_ALIGN(size) >> PAGE_SHIFT; | |
677 | ||
678 | down_write(¤t->mm->mmap_sem); | |
679 | ||
680 | rlim = current->signal->rlim[RLIMIT_AS].rlim_cur >> PAGE_SHIFT; | |
681 | vm = current->mm->total_vm + pgsz; | |
682 | if (rlim < vm) | |
683 | goto out; | |
684 | ||
685 | rlim = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur >> PAGE_SHIFT; | |
686 | vm = current->mm->locked_vm + pgsz; | |
687 | if (rlim < vm) | |
688 | goto out; | |
689 | ||
690 | buffer = kzalloc(size, GFP_KERNEL); | |
691 | if (!buffer) | |
692 | goto out; | |
693 | ||
694 | current->mm->total_vm += pgsz; | |
695 | current->mm->locked_vm += pgsz; | |
696 | ||
697 | out: | |
698 | up_write(¤t->mm->mmap_sem); | |
699 | return buffer; | |
700 | } | |
701 | ||
702 | void free_locked_buffer(void *buffer, size_t size) | |
703 | { | |
704 | unsigned long pgsz = PAGE_ALIGN(size) >> PAGE_SHIFT; | |
705 | ||
706 | down_write(¤t->mm->mmap_sem); | |
707 | ||
708 | current->mm->total_vm -= pgsz; | |
709 | current->mm->locked_vm -= pgsz; | |
710 | ||
711 | up_write(¤t->mm->mmap_sem); | |
712 | ||
713 | kfree(buffer); | |
714 | } |