blob: 49e5e4cb82328dea4e45ee9d81e51d5599df54ff [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * linux/mm/mlock.c
3 *
4 * (C) Copyright 1995 Linus Torvalds
5 * (C) Copyright 2002 Christoph Hellwig
6 */
7
Randy.Dunlapc59ede72006-01-11 12:17:46 -08008#include <linux/capability.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -07009#include <linux/mman.h>
10#include <linux/mm.h>
Nick Pigginb291f002008-10-18 20:26:44 -070011#include <linux/swap.h>
12#include <linux/swapops.h>
13#include <linux/pagemap.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070014#include <linux/mempolicy.h>
15#include <linux/syscalls.h>
Alexey Dobriyane8edc6e2007-05-21 01:22:52 +040016#include <linux/sched.h>
17#include <linux/module.h>
Nick Pigginb291f002008-10-18 20:26:44 -070018#include <linux/rmap.h>
19#include <linux/mmzone.h>
20#include <linux/hugetlb.h>
21
22#include "internal.h"
Linus Torvalds1da177e2005-04-16 15:20:36 -070023
Alexey Dobriyane8edc6e2007-05-21 01:22:52 +040024int can_do_mlock(void)
25{
26 if (capable(CAP_IPC_LOCK))
27 return 1;
Jiri Slaby59e99e52010-03-05 13:41:44 -080028 if (rlimit(RLIMIT_MEMLOCK) != 0)
Alexey Dobriyane8edc6e2007-05-21 01:22:52 +040029 return 1;
30 return 0;
31}
32EXPORT_SYMBOL(can_do_mlock);
Linus Torvalds1da177e2005-04-16 15:20:36 -070033
Nick Pigginb291f002008-10-18 20:26:44 -070034/*
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 */
54void __clear_page_mlock(struct page *page)
55{
56 VM_BUG_ON(!PageLocked(page));
57
58 if (!page->mapping) { /* truncated ? */
59 return;
60 }
61
Nick Piggin5344b7e2008-10-18 20:26:51 -070062 dec_zone_page_state(page, NR_MLOCK);
63 count_vm_event(UNEVICTABLE_PGCLEARED);
Nick Pigginb291f002008-10-18 20:26:44 -070064 if (!isolate_lru_page(page)) {
65 putback_lru_page(page);
66 } else {
67 /*
KOSAKI Motohiro8891d6d2008-11-12 13:26:53 -080068 * We lost the race. the page already moved to evictable list.
Nick Pigginb291f002008-10-18 20:26:44 -070069 */
KOSAKI Motohiro8891d6d2008-11-12 13:26:53 -080070 if (PageUnevictable(page))
Nick Piggin5344b7e2008-10-18 20:26:51 -070071 count_vm_event(UNEVICTABLE_PGSTRANDED);
Nick Pigginb291f002008-10-18 20:26:44 -070072 }
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 */
79void mlock_vma_page(struct page *page)
80{
81 BUG_ON(!PageLocked(page));
82
Nick Piggin5344b7e2008-10-18 20:26:51 -070083 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 }
Nick Pigginb291f002008-10-18 20:26:44 -070089}
90
Lee Schermerhorn6927c1d2009-12-14 17:59:55 -080091/**
92 * munlock_vma_page - munlock a vma page
93 * @page - page to be unlocked
Nick Pigginb291f002008-10-18 20:26:44 -070094 *
Lee Schermerhorn6927c1d2009-12-14 17:59:55 -080095 * 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.
Nick Pigginb291f002008-10-18 20:26:44 -0700105 */
Hugh Dickins73848b42009-12-14 17:59:22 -0800106void munlock_vma_page(struct page *page)
Nick Pigginb291f002008-10-18 20:26:44 -0700107{
108 BUG_ON(!PageLocked(page));
109
Nick Piggin5344b7e2008-10-18 20:26:51 -0700110 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 */
Hugh Dickins53f79ac2009-12-14 17:58:58 -0800117 if (ret != SWAP_MLOCK)
Nick Piggin5344b7e2008-10-18 20:26:51 -0700118 count_vm_event(UNEVICTABLE_PGMUNLOCKED);
119
120 putback_lru_page(page);
121 } else {
122 /*
Lee Schermerhorn6927c1d2009-12-14 17:59:55 -0800123 * 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.
Nick Piggin5344b7e2008-10-18 20:26:51 -0700129 */
130 if (PageUnevictable(page))
131 count_vm_event(UNEVICTABLE_PGSTRANDED);
132 else
133 count_vm_event(UNEVICTABLE_PGMUNLOCKED);
134 }
Nick Pigginb291f002008-10-18 20:26:44 -0700135 }
136}
137
Rik van Rielba470de2008-10-18 20:26:50 -0700138/**
Hugh Dickins408e82b2009-09-21 17:03:23 -0700139 * __mlock_vma_pages_range() - mlock a range of pages in the vma.
Rik van Rielba470de2008-10-18 20:26:50 -0700140 * @vma: target vma
141 * @start: start address
142 * @end: end address
Nick Pigginb291f002008-10-18 20:26:44 -0700143 *
Hugh Dickins408e82b2009-09-21 17:03:23 -0700144 * This takes care of making the pages present too.
Nick Pigginb291f002008-10-18 20:26:44 -0700145 *
Rik van Rielba470de2008-10-18 20:26:50 -0700146 * return 0 on success, negative error code on error.
147 *
148 * vma->vm_mm->mmap_sem must be held for at least read.
Nick Pigginb291f002008-10-18 20:26:44 -0700149 */
Rik van Rielba470de2008-10-18 20:26:50 -0700150static long __mlock_vma_pages_range(struct vm_area_struct *vma,
Hugh Dickins408e82b2009-09-21 17:03:23 -0700151 unsigned long start, unsigned long end)
Nick Pigginb291f002008-10-18 20:26:44 -0700152{
153 struct mm_struct *mm = vma->vm_mm;
154 unsigned long addr = start;
155 struct page *pages[16]; /* 16 gives a reasonable batch */
Nick Pigginb291f002008-10-18 20:26:44 -0700156 int nr_pages = (end - start) / PAGE_SIZE;
Helge Deller72eb8c62008-11-17 00:30:57 +0100157 int ret = 0;
Hugh Dickins408e82b2009-09-21 17:03:23 -0700158 int gup_flags;
Nick Pigginb291f002008-10-18 20:26:44 -0700159
Rik van Rielba470de2008-10-18 20:26:50 -0700160 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);
Hugh Dickins408e82b2009-09-21 17:03:23 -0700164 VM_BUG_ON(!rwsem_is_locked(&mm->mmap_sem));
Rik van Rielba470de2008-10-18 20:26:50 -0700165
Hugh Dickins58fa8792009-09-21 17:03:31 -0700166 gup_flags = FOLL_TOUCH | FOLL_GET;
Rik van Rielba470de2008-10-18 20:26:50 -0700167 if (vma->vm_flags & VM_WRITE)
Hugh Dickins58fa8792009-09-21 17:03:31 -0700168 gup_flags |= FOLL_WRITE;
Nick Pigginb291f002008-10-18 20:26:44 -0700169
Linus Torvaldsd7824372010-08-15 11:35:52 -0700170 /* 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
Nick Pigginb291f002008-10-18 20:26:44 -0700178 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 */
Rik van Rielba470de2008-10-18 20:26:50 -0700189 ret = __get_user_pages(current, mm, addr,
Nick Pigginb291f002008-10-18 20:26:44 -0700190 min_t(int, nr_pages, ARRAY_SIZE(pages)),
Rik van Rielba470de2008-10-18 20:26:50 -0700191 gup_flags, pages, NULL);
Nick Pigginb291f002008-10-18 20:26:44 -0700192 /*
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.
Hugh Dickins408e82b2009-09-21 17:03:23 -0700196 * We'll mlock the pages if/when they get faulted in.
Nick Pigginb291f002008-10-18 20:26:44 -0700197 */
198 if (ret < 0)
199 break;
Nick Pigginb291f002008-10-18 20:26:44 -0700200
201 lru_add_drain(); /* push cached pages to LRU */
202
203 for (i = 0; i < ret; i++) {
204 struct page *page = pages[i];
205
Hugh Dickins6e919712009-09-21 17:03:32 -0700206 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 }
Hugh Dickins408e82b2009-09-21 17:03:23 -0700226 put_page(page); /* ref from get_user_pages() */
Nick Pigginb291f002008-10-18 20:26:44 -0700227 }
Hugh Dickins408e82b2009-09-21 17:03:23 -0700228
229 addr += ret * PAGE_SIZE;
230 nr_pages -= ret;
Lee Schermerhorn9978ad52008-10-18 20:26:56 -0700231 ret = 0;
Nick Pigginb291f002008-10-18 20:26:44 -0700232 }
233
Hugh Dickins408e82b2009-09-21 17:03:23 -0700234 return ret; /* 0 or negative error code */
Lee Schermerhorn9978ad52008-10-18 20:26:56 -0700235}
236
237/*
238 * convert get_user_pages() return value to posix mlock() error
239 */
240static 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;
Nick Pigginb291f002008-10-18 20:26:44 -0700247}
248
Rik van Rielba470de2008-10-18 20:26:50 -0700249/**
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.
Nick Pigginb291f002008-10-18 20:26:44 -0700261 */
Rik van Rielba470de2008-10-18 20:26:50 -0700262long mlock_vma_pages_range(struct vm_area_struct *vma,
Nick Pigginb291f002008-10-18 20:26:44 -0700263 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) ||
Lee Schermerhorn8edb08c2008-10-18 20:26:49 -0700276 vma == get_gate_vma(current))) {
Rik van Rielba470de2008-10-18 20:26:50 -0700277
Hugh Dickins408e82b2009-09-21 17:03:23 -0700278 __mlock_vma_pages_range(vma, start, end);
Hugh Dickinsd5b56232009-02-08 20:56:58 +0000279
280 /* Hide errors from mmap() and other callers */
281 return 0;
Lee Schermerhorn8edb08c2008-10-18 20:26:49 -0700282 }
Nick Pigginb291f002008-10-18 20:26:44 -0700283
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
294no_mlock:
295 vma->vm_flags &= ~VM_LOCKED; /* and don't come back! */
Rik van Rielba470de2008-10-18 20:26:50 -0700296 return nr_pages; /* error or pages NOT mlocked */
Nick Pigginb291f002008-10-18 20:26:44 -0700297}
298
Nick Pigginb291f002008-10-18 20:26:44 -0700299/*
Rik van Rielba470de2008-10-18 20:26:50 -0700300 * 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.
Nick Pigginb291f002008-10-18 20:26:44 -0700316 */
Rik van Rielba470de2008-10-18 20:26:50 -0700317void munlock_vma_pages_range(struct vm_area_struct *vma,
Hugh Dickins408e82b2009-09-21 17:03:23 -0700318 unsigned long start, unsigned long end)
Nick Pigginb291f002008-10-18 20:26:44 -0700319{
Hugh Dickins408e82b2009-09-21 17:03:23 -0700320 unsigned long addr;
321
322 lru_add_drain();
Nick Pigginb291f002008-10-18 20:26:44 -0700323 vma->vm_flags &= ~VM_LOCKED;
Hugh Dickins408e82b2009-09-21 17:03:23 -0700324
325 for (addr = start; addr < end; addr += PAGE_SIZE) {
Hugh Dickins6e919712009-09-21 17:03:32 -0700326 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)) {
Hugh Dickins408e82b2009-09-21 17:03:23 -0700336 lock_page(page);
Hugh Dickins6e919712009-09-21 17:03:32 -0700337 /*
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 */
Hugh Dickins408e82b2009-09-21 17:03:23 -0700343 if (page->mapping)
344 munlock_vma_page(page);
345 unlock_page(page);
346 put_page(page);
347 }
348 cond_resched();
349 }
Nick Pigginb291f002008-10-18 20:26:44 -0700350}
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 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700361static int mlock_fixup(struct vm_area_struct *vma, struct vm_area_struct **prev,
362 unsigned long start, unsigned long end, unsigned int newflags)
363{
Nick Pigginb291f002008-10-18 20:26:44 -0700364 struct mm_struct *mm = vma->vm_mm;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700365 pgoff_t pgoff;
Nick Pigginb291f002008-10-18 20:26:44 -0700366 int nr_pages;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700367 int ret = 0;
Nick Pigginb291f002008-10-18 20:26:44 -0700368 int lock = newflags & VM_LOCKED;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700369
Nick Pigginb291f002008-10-18 20:26:44 -0700370 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 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700380 }
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
Linus Torvalds1da177e2005-04-16 15:20:36 -0700390 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
402success:
403 /*
Nick Pigginb291f002008-10-18 20:26:44 -0700404 * 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
411 /*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700412 * 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
Nick Pigginb291f002008-10-18 20:26:44 -0700414 * set VM_LOCKED, __mlock_vma_pages_range will bring it back.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700415 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700416
Nick Pigginb291f002008-10-18 20:26:44 -0700417 if (lock) {
Hugh Dickins408e82b2009-09-21 17:03:23 -0700418 vma->vm_flags = newflags;
419 ret = __mlock_vma_pages_range(vma, start, end);
420 if (ret < 0)
421 ret = __mlock_posix_error_return(ret);
Lee Schermerhorn8edb08c2008-10-18 20:26:49 -0700422 } else {
Hugh Dickins408e82b2009-09-21 17:03:23 -0700423 munlock_vma_pages_range(vma, start, end);
Lee Schermerhorn8edb08c2008-10-18 20:26:49 -0700424 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700425
Linus Torvalds1da177e2005-04-16 15:20:36 -0700426out:
Nick Pigginb291f002008-10-18 20:26:44 -0700427 *prev = vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700428 return ret;
429}
430
431static 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
Heiko Carstens6a6160a2009-01-14 14:14:15 +0100480SYSCALL_DEFINE2(mlock, unsigned long, start, size_t, len)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700481{
482 unsigned long locked;
483 unsigned long lock_limit;
484 int error = -ENOMEM;
485
486 if (!can_do_mlock())
487 return -EPERM;
488
KOSAKI Motohiro8891d6d2008-11-12 13:26:53 -0800489 lru_add_drain_all(); /* flush pagevec */
490
Linus Torvalds1da177e2005-04-16 15:20:36 -0700491 down_write(&current->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
Jiri Slaby59e99e52010-03-05 13:41:44 -0800498 lock_limit = rlimit(RLIMIT_MEMLOCK);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700499 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(&current->mm->mmap_sem);
505 return error;
506}
507
Heiko Carstens6a6160a2009-01-14 14:14:15 +0100508SYSCALL_DEFINE2(munlock, unsigned long, start, size_t, len)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700509{
510 int ret;
511
512 down_write(&current->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(&current->mm->mmap_sem);
517 return ret;
518}
519
520static 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 }
541out:
542 return 0;
543}
544
Heiko Carstens3480b252009-01-14 14:14:16 +0100545SYSCALL_DEFINE1(mlockall, int, flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700546{
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
KOSAKI Motohiro8891d6d2008-11-12 13:26:53 -0800557 lru_add_drain_all(); /* flush pagevec */
558
Linus Torvalds1da177e2005-04-16 15:20:36 -0700559 down_write(&current->mm->mmap_sem);
560
Jiri Slaby59e99e52010-03-05 13:41:44 -0800561 lock_limit = rlimit(RLIMIT_MEMLOCK);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700562 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(&current->mm->mmap_sem);
569out:
570 return ret;
571}
572
Heiko Carstens3480b252009-01-14 14:14:16 +0100573SYSCALL_DEFINE0(munlockall)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700574{
575 int ret;
576
577 down_write(&current->mm->mmap_sem);
578 ret = do_mlockall(0);
579 up_write(&current->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 */
587static DEFINE_SPINLOCK(shmlock_user_lock);
588
589int 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;
Jiri Slaby59e99e52010-03-05 13:41:44 -0800595 lock_limit = rlimit(RLIMIT_MEMLOCK);
Herbert van den Bergh5ed44a42007-07-15 23:38:25 -0700596 if (lock_limit == RLIM_INFINITY)
597 allowed = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700598 lock_limit >>= PAGE_SHIFT;
599 spin_lock(&shmlock_user_lock);
Herbert van den Bergh5ed44a42007-07-15 23:38:25 -0700600 if (!allowed &&
601 locked + user->locked_shm > lock_limit && !capable(CAP_IPC_LOCK))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700602 goto out;
603 get_uid(user);
604 user->locked_shm += locked;
605 allowed = 1;
606out:
607 spin_unlock(&shmlock_user_lock);
608 return allowed;
609}
610
611void 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}