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 | 16 | #include <linux/sched.h> |
b95f1b31 | 17 | #include <linux/export.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 | */ | |
e6c509f8 | 54 | void clear_page_mlock(struct page *page) |
b291f000 | 55 | { |
e6c509f8 | 56 | if (!TestClearPageMlocked(page)) |
b291f000 | 57 | return; |
b291f000 | 58 | |
8449d21f DR |
59 | mod_zone_page_state(page_zone(page), NR_MLOCK, |
60 | -hpage_nr_pages(page)); | |
5344b7e6 | 61 | count_vm_event(UNEVICTABLE_PGCLEARED); |
b291f000 NP |
62 | if (!isolate_lru_page(page)) { |
63 | putback_lru_page(page); | |
64 | } else { | |
65 | /* | |
8891d6da | 66 | * We lost the race. the page already moved to evictable list. |
b291f000 | 67 | */ |
8891d6da | 68 | if (PageUnevictable(page)) |
5344b7e6 | 69 | count_vm_event(UNEVICTABLE_PGSTRANDED); |
b291f000 NP |
70 | } |
71 | } | |
72 | ||
73 | /* | |
74 | * Mark page as mlocked if not already. | |
75 | * If page on LRU, isolate and putback to move to unevictable list. | |
76 | */ | |
77 | void mlock_vma_page(struct page *page) | |
78 | { | |
79 | BUG_ON(!PageLocked(page)); | |
80 | ||
5344b7e6 | 81 | if (!TestSetPageMlocked(page)) { |
8449d21f DR |
82 | mod_zone_page_state(page_zone(page), NR_MLOCK, |
83 | hpage_nr_pages(page)); | |
5344b7e6 NP |
84 | count_vm_event(UNEVICTABLE_PGMLOCKED); |
85 | if (!isolate_lru_page(page)) | |
86 | putback_lru_page(page); | |
87 | } | |
b291f000 NP |
88 | } |
89 | ||
6927c1dd LS |
90 | /** |
91 | * munlock_vma_page - munlock a vma page | |
92 | * @page - page to be unlocked | |
b291f000 | 93 | * |
6927c1dd LS |
94 | * called from munlock()/munmap() path with page supposedly on the LRU. |
95 | * When we munlock a page, because the vma where we found the page is being | |
96 | * munlock()ed or munmap()ed, we want to check whether other vmas hold the | |
97 | * page locked so that we can leave it on the unevictable lru list and not | |
98 | * bother vmscan with it. However, to walk the page's rmap list in | |
99 | * try_to_munlock() we must isolate the page from the LRU. If some other | |
100 | * task has removed the page from the LRU, we won't be able to do that. | |
101 | * So we clear the PageMlocked as we might not get another chance. If we | |
102 | * can't isolate the page, we leave it for putback_lru_page() and vmscan | |
103 | * [page_referenced()/try_to_unmap()] to deal with. | |
b291f000 | 104 | */ |
73848b46 | 105 | void munlock_vma_page(struct page *page) |
b291f000 NP |
106 | { |
107 | BUG_ON(!PageLocked(page)); | |
108 | ||
5344b7e6 | 109 | if (TestClearPageMlocked(page)) { |
8449d21f DR |
110 | mod_zone_page_state(page_zone(page), NR_MLOCK, |
111 | -hpage_nr_pages(page)); | |
5344b7e6 | 112 | if (!isolate_lru_page(page)) { |
3d470fc3 HD |
113 | int ret = SWAP_AGAIN; |
114 | ||
115 | /* | |
116 | * Optimization: if the page was mapped just once, | |
117 | * that's our mapping and we don't need to check all the | |
118 | * other vmas. | |
119 | */ | |
120 | if (page_mapcount(page) > 1) | |
121 | ret = try_to_munlock(page); | |
5344b7e6 NP |
122 | /* |
123 | * did try_to_unlock() succeed or punt? | |
124 | */ | |
53f79acb | 125 | if (ret != SWAP_MLOCK) |
5344b7e6 NP |
126 | count_vm_event(UNEVICTABLE_PGMUNLOCKED); |
127 | ||
128 | putback_lru_page(page); | |
129 | } else { | |
130 | /* | |
6927c1dd LS |
131 | * Some other task has removed the page from the LRU. |
132 | * putback_lru_page() will take care of removing the | |
133 | * page from the unevictable list, if necessary. | |
134 | * vmscan [page_referenced()] will move the page back | |
135 | * to the unevictable list if some other vma has it | |
136 | * mlocked. | |
5344b7e6 NP |
137 | */ |
138 | if (PageUnevictable(page)) | |
139 | count_vm_event(UNEVICTABLE_PGSTRANDED); | |
140 | else | |
141 | count_vm_event(UNEVICTABLE_PGMUNLOCKED); | |
142 | } | |
b291f000 NP |
143 | } |
144 | } | |
145 | ||
ba470de4 | 146 | /** |
408e82b7 | 147 | * __mlock_vma_pages_range() - mlock a range of pages in the vma. |
ba470de4 RR |
148 | * @vma: target vma |
149 | * @start: start address | |
150 | * @end: end address | |
ba470de4 | 151 | * |
408e82b7 | 152 | * This takes care of making the pages present too. |
b291f000 | 153 | * |
ba470de4 | 154 | * return 0 on success, negative error code on error. |
b291f000 | 155 | * |
ba470de4 | 156 | * vma->vm_mm->mmap_sem must be held for at least read. |
b291f000 | 157 | */ |
ba470de4 | 158 | static long __mlock_vma_pages_range(struct vm_area_struct *vma, |
53a7706d ML |
159 | unsigned long start, unsigned long end, |
160 | int *nonblocking) | |
b291f000 NP |
161 | { |
162 | struct mm_struct *mm = vma->vm_mm; | |
163 | unsigned long addr = start; | |
b291f000 | 164 | int nr_pages = (end - start) / PAGE_SIZE; |
408e82b7 | 165 | int gup_flags; |
ba470de4 RR |
166 | |
167 | VM_BUG_ON(start & ~PAGE_MASK); | |
168 | VM_BUG_ON(end & ~PAGE_MASK); | |
169 | VM_BUG_ON(start < vma->vm_start); | |
170 | VM_BUG_ON(end > vma->vm_end); | |
408e82b7 | 171 | VM_BUG_ON(!rwsem_is_locked(&mm->mmap_sem)); |
b291f000 | 172 | |
a1fde08c | 173 | gup_flags = FOLL_TOUCH | FOLL_MLOCK; |
5ecfda04 ML |
174 | /* |
175 | * We want to touch writable mappings with a write fault in order | |
176 | * to break COW, except for shared mappings because these don't COW | |
177 | * and we would not want to dirty them for nothing. | |
178 | */ | |
179 | if ((vma->vm_flags & (VM_WRITE | VM_SHARED)) == VM_WRITE) | |
58fa879e | 180 | gup_flags |= FOLL_WRITE; |
b291f000 | 181 | |
fdf4c587 ML |
182 | /* |
183 | * We want mlock to succeed for regions that have any permissions | |
184 | * other than PROT_NONE. | |
185 | */ | |
186 | if (vma->vm_flags & (VM_READ | VM_WRITE | VM_EXEC)) | |
187 | gup_flags |= FOLL_FORCE; | |
188 | ||
53a7706d ML |
189 | return __get_user_pages(current, mm, addr, nr_pages, gup_flags, |
190 | NULL, NULL, nonblocking); | |
9978ad58 LS |
191 | } |
192 | ||
193 | /* | |
194 | * convert get_user_pages() return value to posix mlock() error | |
195 | */ | |
196 | static int __mlock_posix_error_return(long retval) | |
197 | { | |
198 | if (retval == -EFAULT) | |
199 | retval = -ENOMEM; | |
200 | else if (retval == -ENOMEM) | |
201 | retval = -EAGAIN; | |
202 | return retval; | |
b291f000 NP |
203 | } |
204 | ||
ba470de4 RR |
205 | /** |
206 | * mlock_vma_pages_range() - mlock pages in specified vma range. | |
207 | * @vma - the vma containing the specfied address range | |
208 | * @start - starting address in @vma to mlock | |
209 | * @end - end address [+1] in @vma to mlock | |
210 | * | |
211 | * For mmap()/mremap()/expansion of mlocked vma. | |
212 | * | |
213 | * return 0 on success for "normal" vmas. | |
214 | * | |
215 | * return number of pages [> 0] to be removed from locked_vm on success | |
216 | * of "special" vmas. | |
b291f000 | 217 | */ |
ba470de4 | 218 | long mlock_vma_pages_range(struct vm_area_struct *vma, |
b291f000 NP |
219 | unsigned long start, unsigned long end) |
220 | { | |
221 | int nr_pages = (end - start) / PAGE_SIZE; | |
222 | BUG_ON(!(vma->vm_flags & VM_LOCKED)); | |
223 | ||
224 | /* | |
225 | * filter unlockable vmas | |
226 | */ | |
227 | if (vma->vm_flags & (VM_IO | VM_PFNMAP)) | |
228 | goto no_mlock; | |
229 | ||
314e51b9 | 230 | if (!((vma->vm_flags & VM_DONTEXPAND) || |
b291f000 | 231 | is_vm_hugetlb_page(vma) || |
31db58b3 | 232 | vma == get_gate_vma(current->mm))) { |
8edb08ca | 233 | |
53a7706d | 234 | __mlock_vma_pages_range(vma, start, end, NULL); |
d5b56233 HD |
235 | |
236 | /* Hide errors from mmap() and other callers */ | |
237 | return 0; | |
8edb08ca | 238 | } |
b291f000 NP |
239 | |
240 | /* | |
241 | * User mapped kernel pages or huge pages: | |
242 | * make these pages present to populate the ptes, but | |
243 | * fall thru' to reset VM_LOCKED--no need to unlock, and | |
244 | * return nr_pages so these don't get counted against task's | |
245 | * locked limit. huge pages are already counted against | |
246 | * locked vm limit. | |
247 | */ | |
248 | make_pages_present(start, end); | |
249 | ||
250 | no_mlock: | |
251 | vma->vm_flags &= ~VM_LOCKED; /* and don't come back! */ | |
ba470de4 | 252 | return nr_pages; /* error or pages NOT mlocked */ |
b291f000 NP |
253 | } |
254 | ||
b291f000 | 255 | /* |
ba470de4 RR |
256 | * munlock_vma_pages_range() - munlock all pages in the vma range.' |
257 | * @vma - vma containing range to be munlock()ed. | |
258 | * @start - start address in @vma of the range | |
259 | * @end - end of range in @vma. | |
260 | * | |
261 | * For mremap(), munmap() and exit(). | |
262 | * | |
263 | * Called with @vma VM_LOCKED. | |
264 | * | |
265 | * Returns with VM_LOCKED cleared. Callers must be prepared to | |
266 | * deal with this. | |
267 | * | |
268 | * We don't save and restore VM_LOCKED here because pages are | |
269 | * still on lru. In unmap path, pages might be scanned by reclaim | |
270 | * and re-mlocked by try_to_{munlock|unmap} before we unmap and | |
271 | * free them. This will result in freeing mlocked pages. | |
b291f000 | 272 | */ |
ba470de4 | 273 | void munlock_vma_pages_range(struct vm_area_struct *vma, |
408e82b7 | 274 | unsigned long start, unsigned long end) |
b291f000 | 275 | { |
408e82b7 HD |
276 | unsigned long addr; |
277 | ||
278 | lru_add_drain(); | |
b291f000 | 279 | vma->vm_flags &= ~VM_LOCKED; |
408e82b7 HD |
280 | |
281 | for (addr = start; addr < end; addr += PAGE_SIZE) { | |
6e919717 HD |
282 | struct page *page; |
283 | /* | |
284 | * Although FOLL_DUMP is intended for get_dump_page(), | |
285 | * it just so happens that its special treatment of the | |
286 | * ZERO_PAGE (returning an error instead of doing get_page) | |
287 | * suits munlock very well (and if somehow an abnormal page | |
288 | * has sneaked into the range, we won't oops here: great). | |
289 | */ | |
290 | page = follow_page(vma, addr, FOLL_GET | FOLL_DUMP); | |
291 | if (page && !IS_ERR(page)) { | |
408e82b7 | 292 | lock_page(page); |
e6c509f8 | 293 | munlock_vma_page(page); |
408e82b7 HD |
294 | unlock_page(page); |
295 | put_page(page); | |
296 | } | |
297 | cond_resched(); | |
298 | } | |
b291f000 NP |
299 | } |
300 | ||
301 | /* | |
302 | * mlock_fixup - handle mlock[all]/munlock[all] requests. | |
303 | * | |
304 | * Filters out "special" vmas -- VM_LOCKED never gets set for these, and | |
305 | * munlock is a no-op. However, for some special vmas, we go ahead and | |
306 | * populate the ptes via make_pages_present(). | |
307 | * | |
308 | * For vmas that pass the filters, merge/split as appropriate. | |
309 | */ | |
1da177e4 | 310 | static int mlock_fixup(struct vm_area_struct *vma, struct vm_area_struct **prev, |
ca16d140 | 311 | unsigned long start, unsigned long end, vm_flags_t newflags) |
1da177e4 | 312 | { |
b291f000 | 313 | struct mm_struct *mm = vma->vm_mm; |
1da177e4 | 314 | pgoff_t pgoff; |
b291f000 | 315 | int nr_pages; |
1da177e4 | 316 | int ret = 0; |
ca16d140 | 317 | int lock = !!(newflags & VM_LOCKED); |
1da177e4 | 318 | |
fed067da | 319 | if (newflags == vma->vm_flags || (vma->vm_flags & VM_SPECIAL) || |
31db58b3 | 320 | is_vm_hugetlb_page(vma) || vma == get_gate_vma(current->mm)) |
b291f000 NP |
321 | goto out; /* don't set VM_LOCKED, don't count */ |
322 | ||
1da177e4 LT |
323 | pgoff = vma->vm_pgoff + ((start - vma->vm_start) >> PAGE_SHIFT); |
324 | *prev = vma_merge(mm, *prev, start, end, newflags, vma->anon_vma, | |
325 | vma->vm_file, pgoff, vma_policy(vma)); | |
326 | if (*prev) { | |
327 | vma = *prev; | |
328 | goto success; | |
329 | } | |
330 | ||
1da177e4 LT |
331 | if (start != vma->vm_start) { |
332 | ret = split_vma(mm, vma, start, 1); | |
333 | if (ret) | |
334 | goto out; | |
335 | } | |
336 | ||
337 | if (end != vma->vm_end) { | |
338 | ret = split_vma(mm, vma, end, 0); | |
339 | if (ret) | |
340 | goto out; | |
341 | } | |
342 | ||
343 | success: | |
b291f000 NP |
344 | /* |
345 | * Keep track of amount of locked VM. | |
346 | */ | |
347 | nr_pages = (end - start) >> PAGE_SHIFT; | |
348 | if (!lock) | |
349 | nr_pages = -nr_pages; | |
350 | mm->locked_vm += nr_pages; | |
351 | ||
1da177e4 LT |
352 | /* |
353 | * vm_flags is protected by the mmap_sem held in write mode. | |
354 | * It's okay if try_to_unmap_one unmaps a page just after we | |
b291f000 | 355 | * set VM_LOCKED, __mlock_vma_pages_range will bring it back. |
1da177e4 | 356 | */ |
1da177e4 | 357 | |
fed067da | 358 | if (lock) |
408e82b7 | 359 | vma->vm_flags = newflags; |
fed067da | 360 | else |
408e82b7 | 361 | munlock_vma_pages_range(vma, start, end); |
1da177e4 | 362 | |
1da177e4 | 363 | out: |
b291f000 | 364 | *prev = vma; |
1da177e4 LT |
365 | return ret; |
366 | } | |
367 | ||
368 | static int do_mlock(unsigned long start, size_t len, int on) | |
369 | { | |
370 | unsigned long nstart, end, tmp; | |
371 | struct vm_area_struct * vma, * prev; | |
372 | int error; | |
373 | ||
fed067da ML |
374 | VM_BUG_ON(start & ~PAGE_MASK); |
375 | VM_BUG_ON(len != PAGE_ALIGN(len)); | |
1da177e4 LT |
376 | end = start + len; |
377 | if (end < start) | |
378 | return -EINVAL; | |
379 | if (end == start) | |
380 | return 0; | |
097d5910 | 381 | vma = find_vma(current->mm, start); |
1da177e4 LT |
382 | if (!vma || vma->vm_start > start) |
383 | return -ENOMEM; | |
384 | ||
097d5910 | 385 | prev = vma->vm_prev; |
1da177e4 LT |
386 | if (start > vma->vm_start) |
387 | prev = vma; | |
388 | ||
389 | for (nstart = start ; ; ) { | |
ca16d140 | 390 | vm_flags_t newflags; |
1da177e4 LT |
391 | |
392 | /* Here we know that vma->vm_start <= nstart < vma->vm_end. */ | |
393 | ||
394 | newflags = vma->vm_flags | VM_LOCKED; | |
395 | if (!on) | |
396 | newflags &= ~VM_LOCKED; | |
397 | ||
398 | tmp = vma->vm_end; | |
399 | if (tmp > end) | |
400 | tmp = end; | |
401 | error = mlock_fixup(vma, &prev, nstart, tmp, newflags); | |
402 | if (error) | |
403 | break; | |
404 | nstart = tmp; | |
405 | if (nstart < prev->vm_end) | |
406 | nstart = prev->vm_end; | |
407 | if (nstart >= end) | |
408 | break; | |
409 | ||
410 | vma = prev->vm_next; | |
411 | if (!vma || vma->vm_start != nstart) { | |
412 | error = -ENOMEM; | |
413 | break; | |
414 | } | |
415 | } | |
416 | return error; | |
417 | } | |
418 | ||
fed067da ML |
419 | static int do_mlock_pages(unsigned long start, size_t len, int ignore_errors) |
420 | { | |
421 | struct mm_struct *mm = current->mm; | |
422 | unsigned long end, nstart, nend; | |
423 | struct vm_area_struct *vma = NULL; | |
53a7706d | 424 | int locked = 0; |
fed067da ML |
425 | int ret = 0; |
426 | ||
427 | VM_BUG_ON(start & ~PAGE_MASK); | |
428 | VM_BUG_ON(len != PAGE_ALIGN(len)); | |
429 | end = start + len; | |
430 | ||
fed067da ML |
431 | for (nstart = start; nstart < end; nstart = nend) { |
432 | /* | |
433 | * We want to fault in pages for [nstart; end) address range. | |
434 | * Find first corresponding VMA. | |
435 | */ | |
53a7706d ML |
436 | if (!locked) { |
437 | locked = 1; | |
438 | down_read(&mm->mmap_sem); | |
fed067da | 439 | vma = find_vma(mm, nstart); |
53a7706d | 440 | } else if (nstart >= vma->vm_end) |
fed067da ML |
441 | vma = vma->vm_next; |
442 | if (!vma || vma->vm_start >= end) | |
443 | break; | |
444 | /* | |
445 | * Set [nstart; nend) to intersection of desired address | |
446 | * range with the first VMA. Also, skip undesirable VMA types. | |
447 | */ | |
448 | nend = min(end, vma->vm_end); | |
449 | if (vma->vm_flags & (VM_IO | VM_PFNMAP)) | |
450 | continue; | |
451 | if (nstart < vma->vm_start) | |
452 | nstart = vma->vm_start; | |
453 | /* | |
53a7706d ML |
454 | * Now fault in a range of pages. __mlock_vma_pages_range() |
455 | * double checks the vma flags, so that it won't mlock pages | |
456 | * if the vma was already munlocked. | |
fed067da | 457 | */ |
53a7706d ML |
458 | ret = __mlock_vma_pages_range(vma, nstart, nend, &locked); |
459 | if (ret < 0) { | |
460 | if (ignore_errors) { | |
461 | ret = 0; | |
462 | continue; /* continue at next VMA */ | |
463 | } | |
5fdb2002 ML |
464 | ret = __mlock_posix_error_return(ret); |
465 | break; | |
466 | } | |
53a7706d ML |
467 | nend = nstart + ret * PAGE_SIZE; |
468 | ret = 0; | |
fed067da | 469 | } |
53a7706d ML |
470 | if (locked) |
471 | up_read(&mm->mmap_sem); | |
fed067da ML |
472 | return ret; /* 0 or negative error code */ |
473 | } | |
474 | ||
6a6160a7 | 475 | SYSCALL_DEFINE2(mlock, unsigned long, start, size_t, len) |
1da177e4 LT |
476 | { |
477 | unsigned long locked; | |
478 | unsigned long lock_limit; | |
479 | int error = -ENOMEM; | |
480 | ||
481 | if (!can_do_mlock()) | |
482 | return -EPERM; | |
483 | ||
8891d6da KM |
484 | lru_add_drain_all(); /* flush pagevec */ |
485 | ||
1da177e4 LT |
486 | down_write(¤t->mm->mmap_sem); |
487 | len = PAGE_ALIGN(len + (start & ~PAGE_MASK)); | |
488 | start &= PAGE_MASK; | |
489 | ||
490 | locked = len >> PAGE_SHIFT; | |
491 | locked += current->mm->locked_vm; | |
492 | ||
59e99e5b | 493 | lock_limit = rlimit(RLIMIT_MEMLOCK); |
1da177e4 LT |
494 | lock_limit >>= PAGE_SHIFT; |
495 | ||
496 | /* check against resource limits */ | |
497 | if ((locked <= lock_limit) || capable(CAP_IPC_LOCK)) | |
498 | error = do_mlock(start, len, 1); | |
499 | up_write(¤t->mm->mmap_sem); | |
fed067da ML |
500 | if (!error) |
501 | error = do_mlock_pages(start, len, 0); | |
1da177e4 LT |
502 | return error; |
503 | } | |
504 | ||
6a6160a7 | 505 | SYSCALL_DEFINE2(munlock, unsigned long, start, size_t, len) |
1da177e4 LT |
506 | { |
507 | int ret; | |
508 | ||
509 | down_write(¤t->mm->mmap_sem); | |
510 | len = PAGE_ALIGN(len + (start & ~PAGE_MASK)); | |
511 | start &= PAGE_MASK; | |
512 | ret = do_mlock(start, len, 0); | |
513 | up_write(¤t->mm->mmap_sem); | |
514 | return ret; | |
515 | } | |
516 | ||
517 | static int do_mlockall(int flags) | |
518 | { | |
519 | struct vm_area_struct * vma, * prev = NULL; | |
520 | unsigned int def_flags = 0; | |
521 | ||
522 | if (flags & MCL_FUTURE) | |
523 | def_flags = VM_LOCKED; | |
524 | current->mm->def_flags = def_flags; | |
525 | if (flags == MCL_FUTURE) | |
526 | goto out; | |
527 | ||
528 | for (vma = current->mm->mmap; vma ; vma = prev->vm_next) { | |
ca16d140 | 529 | vm_flags_t newflags; |
1da177e4 LT |
530 | |
531 | newflags = vma->vm_flags | VM_LOCKED; | |
532 | if (!(flags & MCL_CURRENT)) | |
533 | newflags &= ~VM_LOCKED; | |
534 | ||
535 | /* Ignore errors */ | |
536 | mlock_fixup(vma, &prev, vma->vm_start, vma->vm_end, newflags); | |
537 | } | |
538 | out: | |
539 | return 0; | |
540 | } | |
541 | ||
3480b257 | 542 | SYSCALL_DEFINE1(mlockall, int, flags) |
1da177e4 LT |
543 | { |
544 | unsigned long lock_limit; | |
545 | int ret = -EINVAL; | |
546 | ||
547 | if (!flags || (flags & ~(MCL_CURRENT | MCL_FUTURE))) | |
548 | goto out; | |
549 | ||
550 | ret = -EPERM; | |
551 | if (!can_do_mlock()) | |
552 | goto out; | |
553 | ||
df9d6985 CL |
554 | if (flags & MCL_CURRENT) |
555 | lru_add_drain_all(); /* flush pagevec */ | |
8891d6da | 556 | |
1da177e4 LT |
557 | down_write(¤t->mm->mmap_sem); |
558 | ||
59e99e5b | 559 | lock_limit = rlimit(RLIMIT_MEMLOCK); |
1da177e4 LT |
560 | lock_limit >>= PAGE_SHIFT; |
561 | ||
562 | ret = -ENOMEM; | |
563 | if (!(flags & MCL_CURRENT) || (current->mm->total_vm <= lock_limit) || | |
564 | capable(CAP_IPC_LOCK)) | |
565 | ret = do_mlockall(flags); | |
566 | up_write(¤t->mm->mmap_sem); | |
fed067da ML |
567 | if (!ret && (flags & MCL_CURRENT)) { |
568 | /* Ignore errors */ | |
569 | do_mlock_pages(0, TASK_SIZE, 1); | |
570 | } | |
1da177e4 LT |
571 | out: |
572 | return ret; | |
573 | } | |
574 | ||
3480b257 | 575 | SYSCALL_DEFINE0(munlockall) |
1da177e4 LT |
576 | { |
577 | int ret; | |
578 | ||
579 | down_write(¤t->mm->mmap_sem); | |
580 | ret = do_mlockall(0); | |
581 | up_write(¤t->mm->mmap_sem); | |
582 | return ret; | |
583 | } | |
584 | ||
585 | /* | |
586 | * Objects with different lifetime than processes (SHM_LOCK and SHM_HUGETLB | |
587 | * shm segments) get accounted against the user_struct instead. | |
588 | */ | |
589 | static DEFINE_SPINLOCK(shmlock_user_lock); | |
590 | ||
591 | int user_shm_lock(size_t size, struct user_struct *user) | |
592 | { | |
593 | unsigned long lock_limit, locked; | |
594 | int allowed = 0; | |
595 | ||
596 | locked = (size + PAGE_SIZE - 1) >> PAGE_SHIFT; | |
59e99e5b | 597 | lock_limit = rlimit(RLIMIT_MEMLOCK); |
5ed44a40 HB |
598 | if (lock_limit == RLIM_INFINITY) |
599 | allowed = 1; | |
1da177e4 LT |
600 | lock_limit >>= PAGE_SHIFT; |
601 | spin_lock(&shmlock_user_lock); | |
5ed44a40 HB |
602 | if (!allowed && |
603 | locked + user->locked_shm > lock_limit && !capable(CAP_IPC_LOCK)) | |
1da177e4 LT |
604 | goto out; |
605 | get_uid(user); | |
606 | user->locked_shm += locked; | |
607 | allowed = 1; | |
608 | out: | |
609 | spin_unlock(&shmlock_user_lock); | |
610 | return allowed; | |
611 | } | |
612 | ||
613 | void user_shm_unlock(size_t size, struct user_struct *user) | |
614 | { | |
615 | spin_lock(&shmlock_user_lock); | |
616 | user->locked_shm -= (size + PAGE_SIZE - 1) >> PAGE_SHIFT; | |
617 | spin_unlock(&shmlock_user_lock); | |
618 | free_uid(user); | |
619 | } |