blob: e6638f565d42669a17989e45450b23c2ac10662a [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>
Paul Gortmakerb95f1b312011-10-16 02:01:52 -040017#include <linux/export.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 */
Hugh Dickinse6c509f2012-10-08 16:33:19 -070054void clear_page_mlock(struct page *page)
Nick Pigginb291f002008-10-18 20:26:44 -070055{
Hugh Dickinse6c509f2012-10-08 16:33:19 -070056 if (!TestClearPageMlocked(page))
Nick Pigginb291f002008-10-18 20:26:44 -070057 return;
Nick Pigginb291f002008-10-18 20:26:44 -070058
David Rientjes8449d212012-10-08 16:34:06 -070059 mod_zone_page_state(page_zone(page), NR_MLOCK,
60 -hpage_nr_pages(page));
Nick Piggin5344b7e2008-10-18 20:26:51 -070061 count_vm_event(UNEVICTABLE_PGCLEARED);
Nick Pigginb291f002008-10-18 20:26:44 -070062 if (!isolate_lru_page(page)) {
63 putback_lru_page(page);
64 } else {
65 /*
KOSAKI Motohiro8891d6d2008-11-12 13:26:53 -080066 * We lost the race. the page already moved to evictable list.
Nick Pigginb291f002008-10-18 20:26:44 -070067 */
KOSAKI Motohiro8891d6d2008-11-12 13:26:53 -080068 if (PageUnevictable(page))
Nick Piggin5344b7e2008-10-18 20:26:51 -070069 count_vm_event(UNEVICTABLE_PGSTRANDED);
Nick Pigginb291f002008-10-18 20:26:44 -070070 }
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 */
77void mlock_vma_page(struct page *page)
78{
79 BUG_ON(!PageLocked(page));
80
Nick Piggin5344b7e2008-10-18 20:26:51 -070081 if (!TestSetPageMlocked(page)) {
David Rientjes8449d212012-10-08 16:34:06 -070082 mod_zone_page_state(page_zone(page), NR_MLOCK,
83 hpage_nr_pages(page));
Nick Piggin5344b7e2008-10-18 20:26:51 -070084 count_vm_event(UNEVICTABLE_PGMLOCKED);
85 if (!isolate_lru_page(page))
86 putback_lru_page(page);
87 }
Nick Pigginb291f002008-10-18 20:26:44 -070088}
89
Lee Schermerhorn6927c1d2009-12-14 17:59:55 -080090/**
91 * munlock_vma_page - munlock a vma page
92 * @page - page to be unlocked
Nick Pigginb291f002008-10-18 20:26:44 -070093 *
Lee Schermerhorn6927c1d2009-12-14 17:59:55 -080094 * 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.
Nick Pigginb291f002008-10-18 20:26:44 -0700104 */
Hugh Dickins73848b42009-12-14 17:59:22 -0800105void munlock_vma_page(struct page *page)
Nick Pigginb291f002008-10-18 20:26:44 -0700106{
107 BUG_ON(!PageLocked(page));
108
Nick Piggin5344b7e2008-10-18 20:26:51 -0700109 if (TestClearPageMlocked(page)) {
David Rientjes8449d212012-10-08 16:34:06 -0700110 mod_zone_page_state(page_zone(page), NR_MLOCK,
111 -hpage_nr_pages(page));
Nick Piggin5344b7e2008-10-18 20:26:51 -0700112 if (!isolate_lru_page(page)) {
Hugh Dickins3d470fc2011-10-31 17:09:43 -0700113 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);
Nick Piggin5344b7e2008-10-18 20:26:51 -0700122 /*
123 * did try_to_unlock() succeed or punt?
124 */
Hugh Dickins53f79ac2009-12-14 17:58:58 -0800125 if (ret != SWAP_MLOCK)
Nick Piggin5344b7e2008-10-18 20:26:51 -0700126 count_vm_event(UNEVICTABLE_PGMUNLOCKED);
127
128 putback_lru_page(page);
129 } else {
130 /*
Lee Schermerhorn6927c1d2009-12-14 17:59:55 -0800131 * 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.
Nick Piggin5344b7e2008-10-18 20:26:51 -0700137 */
138 if (PageUnevictable(page))
139 count_vm_event(UNEVICTABLE_PGSTRANDED);
140 else
141 count_vm_event(UNEVICTABLE_PGMUNLOCKED);
142 }
Nick Pigginb291f002008-10-18 20:26:44 -0700143 }
144}
145
Rik van Rielba470de2008-10-18 20:26:50 -0700146/**
Hugh Dickins408e82b2009-09-21 17:03:23 -0700147 * __mlock_vma_pages_range() - mlock a range of pages in the vma.
Rik van Rielba470de2008-10-18 20:26:50 -0700148 * @vma: target vma
149 * @start: start address
150 * @end: end address
Nick Pigginb291f002008-10-18 20:26:44 -0700151 *
Hugh Dickins408e82b2009-09-21 17:03:23 -0700152 * This takes care of making the pages present too.
Nick Pigginb291f002008-10-18 20:26:44 -0700153 *
Rik van Rielba470de2008-10-18 20:26:50 -0700154 * return 0 on success, negative error code on error.
155 *
156 * vma->vm_mm->mmap_sem must be held for at least read.
Nick Pigginb291f002008-10-18 20:26:44 -0700157 */
Michel Lespinassecea10a12013-02-22 16:32:44 -0800158long __mlock_vma_pages_range(struct vm_area_struct *vma,
159 unsigned long start, unsigned long end, int *nonblocking)
Nick Pigginb291f002008-10-18 20:26:44 -0700160{
161 struct mm_struct *mm = vma->vm_mm;
162 unsigned long addr = start;
Michel Lespinasse28a35712013-02-22 16:35:55 -0800163 unsigned long nr_pages = (end - start) / PAGE_SIZE;
Hugh Dickins408e82b2009-09-21 17:03:23 -0700164 int gup_flags;
Nick Pigginb291f002008-10-18 20:26:44 -0700165
Rik van Rielba470de2008-10-18 20:26:50 -0700166 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);
Hugh Dickins408e82b2009-09-21 17:03:23 -0700170 VM_BUG_ON(!rwsem_is_locked(&mm->mmap_sem));
Rik van Rielba470de2008-10-18 20:26:50 -0700171
Linus Torvaldsa1fde082011-05-04 21:30:28 -0700172 gup_flags = FOLL_TOUCH | FOLL_MLOCK;
Michel Lespinasse5ecfda02011-01-13 15:46:09 -0800173 /*
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)
Hugh Dickins58fa8792009-09-21 17:03:31 -0700179 gup_flags |= FOLL_WRITE;
Nick Pigginb291f002008-10-18 20:26:44 -0700180
Michel Lespinassefdf4c582011-01-31 17:03:41 -0800181 /*
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
Johannes Weiner4805b022013-02-22 16:35:20 -0800188 /*
189 * We made sure addr is within a VMA, so the following will
190 * not result in a stack expansion that recurses back here.
191 */
Michel Lespinasse53a77062011-01-13 15:46:14 -0800192 return __get_user_pages(current, mm, addr, nr_pages, gup_flags,
193 NULL, NULL, nonblocking);
Lee Schermerhorn9978ad52008-10-18 20:26:56 -0700194}
195
196/*
197 * convert get_user_pages() return value to posix mlock() error
198 */
199static int __mlock_posix_error_return(long retval)
200{
201 if (retval == -EFAULT)
202 retval = -ENOMEM;
203 else if (retval == -ENOMEM)
204 retval = -EAGAIN;
205 return retval;
Nick Pigginb291f002008-10-18 20:26:44 -0700206}
207
Nick Pigginb291f002008-10-18 20:26:44 -0700208/*
Rik van Rielba470de2008-10-18 20:26:50 -0700209 * munlock_vma_pages_range() - munlock all pages in the vma range.'
210 * @vma - vma containing range to be munlock()ed.
211 * @start - start address in @vma of the range
212 * @end - end of range in @vma.
213 *
214 * For mremap(), munmap() and exit().
215 *
216 * Called with @vma VM_LOCKED.
217 *
218 * Returns with VM_LOCKED cleared. Callers must be prepared to
219 * deal with this.
220 *
221 * We don't save and restore VM_LOCKED here because pages are
222 * still on lru. In unmap path, pages might be scanned by reclaim
223 * and re-mlocked by try_to_{munlock|unmap} before we unmap and
224 * free them. This will result in freeing mlocked pages.
Nick Pigginb291f002008-10-18 20:26:44 -0700225 */
Rik van Rielba470de2008-10-18 20:26:50 -0700226void munlock_vma_pages_range(struct vm_area_struct *vma,
Hugh Dickins408e82b2009-09-21 17:03:23 -0700227 unsigned long start, unsigned long end)
Nick Pigginb291f002008-10-18 20:26:44 -0700228{
Hugh Dickins408e82b2009-09-21 17:03:23 -0700229 unsigned long addr;
230
231 lru_add_drain();
Nick Pigginb291f002008-10-18 20:26:44 -0700232 vma->vm_flags &= ~VM_LOCKED;
Hugh Dickins408e82b2009-09-21 17:03:23 -0700233
234 for (addr = start; addr < end; addr += PAGE_SIZE) {
Hugh Dickins6e919712009-09-21 17:03:32 -0700235 struct page *page;
236 /*
237 * Although FOLL_DUMP is intended for get_dump_page(),
238 * it just so happens that its special treatment of the
239 * ZERO_PAGE (returning an error instead of doing get_page)
240 * suits munlock very well (and if somehow an abnormal page
241 * has sneaked into the range, we won't oops here: great).
242 */
243 page = follow_page(vma, addr, FOLL_GET | FOLL_DUMP);
244 if (page && !IS_ERR(page)) {
Hugh Dickins408e82b2009-09-21 17:03:23 -0700245 lock_page(page);
Hugh Dickinse6c509f2012-10-08 16:33:19 -0700246 munlock_vma_page(page);
Hugh Dickins408e82b2009-09-21 17:03:23 -0700247 unlock_page(page);
248 put_page(page);
249 }
250 cond_resched();
251 }
Nick Pigginb291f002008-10-18 20:26:44 -0700252}
253
254/*
255 * mlock_fixup - handle mlock[all]/munlock[all] requests.
256 *
257 * Filters out "special" vmas -- VM_LOCKED never gets set for these, and
258 * munlock is a no-op. However, for some special vmas, we go ahead and
Michel Lespinassecea10a12013-02-22 16:32:44 -0800259 * populate the ptes.
Nick Pigginb291f002008-10-18 20:26:44 -0700260 *
261 * For vmas that pass the filters, merge/split as appropriate.
262 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700263static int mlock_fixup(struct vm_area_struct *vma, struct vm_area_struct **prev,
KOSAKI Motohiroca16d142011-05-26 19:16:19 +0900264 unsigned long start, unsigned long end, vm_flags_t newflags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700265{
Nick Pigginb291f002008-10-18 20:26:44 -0700266 struct mm_struct *mm = vma->vm_mm;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700267 pgoff_t pgoff;
Nick Pigginb291f002008-10-18 20:26:44 -0700268 int nr_pages;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700269 int ret = 0;
KOSAKI Motohiroca16d142011-05-26 19:16:19 +0900270 int lock = !!(newflags & VM_LOCKED);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700271
Michel Lespinassefed067d2011-01-13 15:46:10 -0800272 if (newflags == vma->vm_flags || (vma->vm_flags & VM_SPECIAL) ||
Stephen Wilson31db58b2011-03-13 15:49:15 -0400273 is_vm_hugetlb_page(vma) || vma == get_gate_vma(current->mm))
Nick Pigginb291f002008-10-18 20:26:44 -0700274 goto out; /* don't set VM_LOCKED, don't count */
275
Linus Torvalds1da177e2005-04-16 15:20:36 -0700276 pgoff = vma->vm_pgoff + ((start - vma->vm_start) >> PAGE_SHIFT);
277 *prev = vma_merge(mm, *prev, start, end, newflags, vma->anon_vma,
278 vma->vm_file, pgoff, vma_policy(vma));
279 if (*prev) {
280 vma = *prev;
281 goto success;
282 }
283
Linus Torvalds1da177e2005-04-16 15:20:36 -0700284 if (start != vma->vm_start) {
285 ret = split_vma(mm, vma, start, 1);
286 if (ret)
287 goto out;
288 }
289
290 if (end != vma->vm_end) {
291 ret = split_vma(mm, vma, end, 0);
292 if (ret)
293 goto out;
294 }
295
296success:
297 /*
Nick Pigginb291f002008-10-18 20:26:44 -0700298 * Keep track of amount of locked VM.
299 */
300 nr_pages = (end - start) >> PAGE_SHIFT;
301 if (!lock)
302 nr_pages = -nr_pages;
303 mm->locked_vm += nr_pages;
304
305 /*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700306 * vm_flags is protected by the mmap_sem held in write mode.
307 * It's okay if try_to_unmap_one unmaps a page just after we
Nick Pigginb291f002008-10-18 20:26:44 -0700308 * set VM_LOCKED, __mlock_vma_pages_range will bring it back.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700309 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700310
Michel Lespinassefed067d2011-01-13 15:46:10 -0800311 if (lock)
Hugh Dickins408e82b2009-09-21 17:03:23 -0700312 vma->vm_flags = newflags;
Michel Lespinassefed067d2011-01-13 15:46:10 -0800313 else
Hugh Dickins408e82b2009-09-21 17:03:23 -0700314 munlock_vma_pages_range(vma, start, end);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700315
Linus Torvalds1da177e2005-04-16 15:20:36 -0700316out:
Nick Pigginb291f002008-10-18 20:26:44 -0700317 *prev = vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700318 return ret;
319}
320
321static int do_mlock(unsigned long start, size_t len, int on)
322{
323 unsigned long nstart, end, tmp;
324 struct vm_area_struct * vma, * prev;
325 int error;
326
Michel Lespinassefed067d2011-01-13 15:46:10 -0800327 VM_BUG_ON(start & ~PAGE_MASK);
328 VM_BUG_ON(len != PAGE_ALIGN(len));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700329 end = start + len;
330 if (end < start)
331 return -EINVAL;
332 if (end == start)
333 return 0;
Linus Torvalds097d5912012-03-06 18:23:36 -0800334 vma = find_vma(current->mm, start);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700335 if (!vma || vma->vm_start > start)
336 return -ENOMEM;
337
Linus Torvalds097d5912012-03-06 18:23:36 -0800338 prev = vma->vm_prev;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700339 if (start > vma->vm_start)
340 prev = vma;
341
342 for (nstart = start ; ; ) {
KOSAKI Motohiroca16d142011-05-26 19:16:19 +0900343 vm_flags_t newflags;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700344
345 /* Here we know that vma->vm_start <= nstart < vma->vm_end. */
346
Michel Lespinasse18693052013-02-22 16:32:46 -0800347 newflags = vma->vm_flags & ~VM_LOCKED;
348 if (on)
349 newflags |= VM_LOCKED | VM_POPULATE;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700350
351 tmp = vma->vm_end;
352 if (tmp > end)
353 tmp = end;
354 error = mlock_fixup(vma, &prev, nstart, tmp, newflags);
355 if (error)
356 break;
357 nstart = tmp;
358 if (nstart < prev->vm_end)
359 nstart = prev->vm_end;
360 if (nstart >= end)
361 break;
362
363 vma = prev->vm_next;
364 if (!vma || vma->vm_start != nstart) {
365 error = -ENOMEM;
366 break;
367 }
368 }
369 return error;
370}
371
Michel Lespinassebebeb3d2013-02-22 16:32:37 -0800372/*
373 * __mm_populate - populate and/or mlock pages within a range of address space.
374 *
375 * This is used to implement mlock() and the MAP_POPULATE / MAP_LOCKED mmap
376 * flags. VMAs must be already marked with the desired vm_flags, and
377 * mmap_sem must not be held.
378 */
379int __mm_populate(unsigned long start, unsigned long len, int ignore_errors)
Michel Lespinassefed067d2011-01-13 15:46:10 -0800380{
381 struct mm_struct *mm = current->mm;
382 unsigned long end, nstart, nend;
383 struct vm_area_struct *vma = NULL;
Michel Lespinasse53a77062011-01-13 15:46:14 -0800384 int locked = 0;
Michel Lespinasse28a35712013-02-22 16:35:55 -0800385 long ret = 0;
Michel Lespinassefed067d2011-01-13 15:46:10 -0800386
387 VM_BUG_ON(start & ~PAGE_MASK);
388 VM_BUG_ON(len != PAGE_ALIGN(len));
389 end = start + len;
390
Michel Lespinassefed067d2011-01-13 15:46:10 -0800391 for (nstart = start; nstart < end; nstart = nend) {
392 /*
393 * We want to fault in pages for [nstart; end) address range.
394 * Find first corresponding VMA.
395 */
Michel Lespinasse53a77062011-01-13 15:46:14 -0800396 if (!locked) {
397 locked = 1;
398 down_read(&mm->mmap_sem);
Michel Lespinassefed067d2011-01-13 15:46:10 -0800399 vma = find_vma(mm, nstart);
Michel Lespinasse53a77062011-01-13 15:46:14 -0800400 } else if (nstart >= vma->vm_end)
Michel Lespinassefed067d2011-01-13 15:46:10 -0800401 vma = vma->vm_next;
402 if (!vma || vma->vm_start >= end)
403 break;
404 /*
405 * Set [nstart; nend) to intersection of desired address
406 * range with the first VMA. Also, skip undesirable VMA types.
407 */
408 nend = min(end, vma->vm_end);
Michel Lespinasse18693052013-02-22 16:32:46 -0800409 if ((vma->vm_flags & (VM_IO | VM_PFNMAP | VM_POPULATE)) !=
410 VM_POPULATE)
Michel Lespinassefed067d2011-01-13 15:46:10 -0800411 continue;
412 if (nstart < vma->vm_start)
413 nstart = vma->vm_start;
414 /*
Michel Lespinasse53a77062011-01-13 15:46:14 -0800415 * Now fault in a range of pages. __mlock_vma_pages_range()
416 * double checks the vma flags, so that it won't mlock pages
417 * if the vma was already munlocked.
Michel Lespinassefed067d2011-01-13 15:46:10 -0800418 */
Michel Lespinasse53a77062011-01-13 15:46:14 -0800419 ret = __mlock_vma_pages_range(vma, nstart, nend, &locked);
420 if (ret < 0) {
421 if (ignore_errors) {
422 ret = 0;
423 continue; /* continue at next VMA */
424 }
Michel Lespinasse5fdb2002011-01-13 15:46:12 -0800425 ret = __mlock_posix_error_return(ret);
426 break;
427 }
Michel Lespinasse53a77062011-01-13 15:46:14 -0800428 nend = nstart + ret * PAGE_SIZE;
429 ret = 0;
Michel Lespinassefed067d2011-01-13 15:46:10 -0800430 }
Michel Lespinasse53a77062011-01-13 15:46:14 -0800431 if (locked)
432 up_read(&mm->mmap_sem);
Michel Lespinassefed067d2011-01-13 15:46:10 -0800433 return ret; /* 0 or negative error code */
434}
435
Heiko Carstens6a6160a2009-01-14 14:14:15 +0100436SYSCALL_DEFINE2(mlock, unsigned long, start, size_t, len)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700437{
438 unsigned long locked;
439 unsigned long lock_limit;
440 int error = -ENOMEM;
441
442 if (!can_do_mlock())
443 return -EPERM;
444
KOSAKI Motohiro8891d6d2008-11-12 13:26:53 -0800445 lru_add_drain_all(); /* flush pagevec */
446
Linus Torvalds1da177e2005-04-16 15:20:36 -0700447 down_write(&current->mm->mmap_sem);
448 len = PAGE_ALIGN(len + (start & ~PAGE_MASK));
449 start &= PAGE_MASK;
450
451 locked = len >> PAGE_SHIFT;
452 locked += current->mm->locked_vm;
453
Jiri Slaby59e99e52010-03-05 13:41:44 -0800454 lock_limit = rlimit(RLIMIT_MEMLOCK);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700455 lock_limit >>= PAGE_SHIFT;
456
457 /* check against resource limits */
458 if ((locked <= lock_limit) || capable(CAP_IPC_LOCK))
459 error = do_mlock(start, len, 1);
460 up_write(&current->mm->mmap_sem);
Michel Lespinassefed067d2011-01-13 15:46:10 -0800461 if (!error)
Michel Lespinassebebeb3d2013-02-22 16:32:37 -0800462 error = __mm_populate(start, len, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700463 return error;
464}
465
Heiko Carstens6a6160a2009-01-14 14:14:15 +0100466SYSCALL_DEFINE2(munlock, unsigned long, start, size_t, len)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700467{
468 int ret;
469
470 down_write(&current->mm->mmap_sem);
471 len = PAGE_ALIGN(len + (start & ~PAGE_MASK));
472 start &= PAGE_MASK;
473 ret = do_mlock(start, len, 0);
474 up_write(&current->mm->mmap_sem);
475 return ret;
476}
477
478static int do_mlockall(int flags)
479{
480 struct vm_area_struct * vma, * prev = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700481
482 if (flags & MCL_FUTURE)
Michel Lespinasse18693052013-02-22 16:32:46 -0800483 current->mm->def_flags |= VM_LOCKED | VM_POPULATE;
Gerald Schaefer9977f0f2013-02-12 13:46:20 -0800484 else
Michel Lespinasse18693052013-02-22 16:32:46 -0800485 current->mm->def_flags &= ~(VM_LOCKED | VM_POPULATE);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700486 if (flags == MCL_FUTURE)
487 goto out;
488
489 for (vma = current->mm->mmap; vma ; vma = prev->vm_next) {
KOSAKI Motohiroca16d142011-05-26 19:16:19 +0900490 vm_flags_t newflags;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700491
Michel Lespinasse18693052013-02-22 16:32:46 -0800492 newflags = vma->vm_flags & ~VM_LOCKED;
493 if (flags & MCL_CURRENT)
494 newflags |= VM_LOCKED | VM_POPULATE;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700495
496 /* Ignore errors */
497 mlock_fixup(vma, &prev, vma->vm_start, vma->vm_end, newflags);
498 }
499out:
500 return 0;
501}
502
Heiko Carstens3480b252009-01-14 14:14:16 +0100503SYSCALL_DEFINE1(mlockall, int, flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700504{
505 unsigned long lock_limit;
506 int ret = -EINVAL;
507
508 if (!flags || (flags & ~(MCL_CURRENT | MCL_FUTURE)))
509 goto out;
510
511 ret = -EPERM;
512 if (!can_do_mlock())
513 goto out;
514
Christoph Lameterdf9d6982011-10-31 17:09:35 -0700515 if (flags & MCL_CURRENT)
516 lru_add_drain_all(); /* flush pagevec */
KOSAKI Motohiro8891d6d2008-11-12 13:26:53 -0800517
Linus Torvalds1da177e2005-04-16 15:20:36 -0700518 down_write(&current->mm->mmap_sem);
519
Jiri Slaby59e99e52010-03-05 13:41:44 -0800520 lock_limit = rlimit(RLIMIT_MEMLOCK);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700521 lock_limit >>= PAGE_SHIFT;
522
523 ret = -ENOMEM;
524 if (!(flags & MCL_CURRENT) || (current->mm->total_vm <= lock_limit) ||
525 capable(CAP_IPC_LOCK))
526 ret = do_mlockall(flags);
527 up_write(&current->mm->mmap_sem);
Michel Lespinassebebeb3d2013-02-22 16:32:37 -0800528 if (!ret && (flags & MCL_CURRENT))
529 mm_populate(0, TASK_SIZE);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700530out:
531 return ret;
532}
533
Heiko Carstens3480b252009-01-14 14:14:16 +0100534SYSCALL_DEFINE0(munlockall)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700535{
536 int ret;
537
538 down_write(&current->mm->mmap_sem);
539 ret = do_mlockall(0);
540 up_write(&current->mm->mmap_sem);
541 return ret;
542}
543
544/*
545 * Objects with different lifetime than processes (SHM_LOCK and SHM_HUGETLB
546 * shm segments) get accounted against the user_struct instead.
547 */
548static DEFINE_SPINLOCK(shmlock_user_lock);
549
550int user_shm_lock(size_t size, struct user_struct *user)
551{
552 unsigned long lock_limit, locked;
553 int allowed = 0;
554
555 locked = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
Jiri Slaby59e99e52010-03-05 13:41:44 -0800556 lock_limit = rlimit(RLIMIT_MEMLOCK);
Herbert van den Bergh5ed44a42007-07-15 23:38:25 -0700557 if (lock_limit == RLIM_INFINITY)
558 allowed = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700559 lock_limit >>= PAGE_SHIFT;
560 spin_lock(&shmlock_user_lock);
Herbert van den Bergh5ed44a42007-07-15 23:38:25 -0700561 if (!allowed &&
562 locked + user->locked_shm > lock_limit && !capable(CAP_IPC_LOCK))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700563 goto out;
564 get_uid(user);
565 user->locked_shm += locked;
566 allowed = 1;
567out:
568 spin_unlock(&shmlock_user_lock);
569 return allowed;
570}
571
572void user_shm_unlock(size_t size, struct user_struct *user)
573{
574 spin_lock(&shmlock_user_lock);
575 user->locked_shm -= (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
576 spin_unlock(&shmlock_user_lock);
577 free_uid(user);
578}