1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * linux/mm/mlock.c
4 *
5 * (C) Copyright 1995 Linus Torvalds
6 * (C) Copyright 2002 Christoph Hellwig
7 */
8
9 #include <linux/capability.h>
10 #include <linux/mman.h>
11 #include <linux/mm.h>
12 #include <linux/sched/user.h>
13 #include <linux/swap.h>
14 #include <linux/swapops.h>
15 #include <linux/pagemap.h>
16 #include <linux/pagevec.h>
17 #include <linux/pagewalk.h>
18 #include <linux/mempolicy.h>
19 #include <linux/syscalls.h>
20 #include <linux/sched.h>
21 #include <linux/export.h>
22 #include <linux/rmap.h>
23 #include <linux/mmzone.h>
24 #include <linux/hugetlb.h>
25 #include <linux/memcontrol.h>
26 #include <linux/mm_inline.h>
27 #include <linux/secretmem.h>
28
29 #include "internal.h"
30
31 struct mlock_fbatch {
32 local_lock_t lock;
33 struct folio_batch fbatch;
34 };
35
36 static DEFINE_PER_CPU(struct mlock_fbatch, mlock_fbatch) = {
37 .lock = INIT_LOCAL_LOCK(lock),
38 };
39
40 bool can_do_mlock(void)
41 {
42 if (rlimit(RLIMIT_MEMLOCK) != 0)
43 return true;
44 if (capable(CAP_IPC_LOCK))
45 return true;
46 return false;
47 }
48 EXPORT_SYMBOL(can_do_mlock);
49
50 /*
51 * Mlocked folios are marked with the PG_mlocked flag for efficient testing
52 * in vmscan and, possibly, the fault path; and to support semi-accurate
53 * statistics.
54 *
55 * An mlocked folio [folio_test_mlocked(folio)] is unevictable. As such, it
56 * will be ostensibly placed on the LRU "unevictable" list (actually no such
57 * list exists), rather than the [in]active lists. PG_unevictable is set to
58 * indicate the unevictable state.
59 */
60
61 static struct lruvec *__mlock_folio(struct folio *folio, struct lruvec *lruvec)
62 {
63 /* There is nothing more we can do while it's off LRU */
64 if (!folio_test_clear_lru(folio))
65 return lruvec;
66
67 lruvec = folio_lruvec_relock_irq(folio, lruvec);
68
69 if (unlikely(folio_evictable(folio))) {
70 /*
71 * This is a little surprising, but quite possible: PG_mlocked
72 * must have got cleared already by another CPU. Could this
73 * folio be unevictable? I'm not sure, but move it now if so.
74 */
75 if (folio_test_unevictable(folio)) {
76 lruvec_del_folio(lruvec, folio);
77 folio_clear_unevictable(folio);
78 lruvec_add_folio(lruvec, folio);
79
80 __count_vm_events(UNEVICTABLE_PGRESCUED,
81 folio_nr_pages(folio));
82 }
83 goto out;
84 }
85
86 if (folio_test_unevictable(folio)) {
87 if (folio_test_mlocked(folio))
88 folio->mlock_count++;
89 goto out;
90 }
91
92 lruvec_del_folio(lruvec, folio);
93 folio_clear_active(folio);
94 folio_set_unevictable(folio);
95 folio->mlock_count = !!folio_test_mlocked(folio);
96 lruvec_add_folio(lruvec, folio);
97 __count_vm_events(UNEVICTABLE_PGCULLED, folio_nr_pages(folio));
98 out:
99 folio_set_lru(folio);
100 return lruvec;
101 }
102
103 static struct lruvec *__mlock_new_folio(struct folio *folio, struct lruvec *lruvec)
104 {
105 VM_BUG_ON_FOLIO(folio_test_lru(folio), folio);
106
107 lruvec = folio_lruvec_relock_irq(folio, lruvec);
108
109 /* As above, this is a little surprising, but possible */
110 if (unlikely(folio_evictable(folio)))
111 goto out;
112
113 folio_set_unevictable(folio);
114 folio->mlock_count = !!folio_test_mlocked(folio);
115 __count_vm_events(UNEVICTABLE_PGCULLED, folio_nr_pages(folio));
116 out:
117 lruvec_add_folio(lruvec, folio);
118 folio_set_lru(folio);
119 return lruvec;
120 }
121
122 static struct lruvec *__munlock_folio(struct folio *folio, struct lruvec *lruvec)
123 {
124 int nr_pages = folio_nr_pages(folio);
125 bool isolated = false;
126
127 if (!folio_test_clear_lru(folio))
128 goto munlock;
129
130 isolated = true;
131 lruvec = folio_lruvec_relock_irq(folio, lruvec);
132
133 if (folio_test_unevictable(folio)) {
134 /* Then mlock_count is maintained, but might undercount */
135 if (folio->mlock_count)
136 folio->mlock_count--;
137 if (folio->mlock_count)
138 goto out;
139 }
140 /* else assume that was the last mlock: reclaim will fix it if not */
141
142 munlock:
143 if (folio_test_clear_mlocked(folio)) {
144 __zone_stat_mod_folio(folio, NR_MLOCK, -nr_pages);
145 if (isolated || !folio_test_unevictable(folio))
146 __count_vm_events(UNEVICTABLE_PGMUNLOCKED, nr_pages);
147 else
148 __count_vm_events(UNEVICTABLE_PGSTRANDED, nr_pages);
149 }
150
151 /* folio_evictable() has to be checked *after* clearing Mlocked */
152 if (isolated && folio_test_unevictable(folio) && folio_evictable(folio)) {
153 lruvec_del_folio(lruvec, folio);
154 folio_clear_unevictable(folio);
155 lruvec_add_folio(lruvec, folio);
156 __count_vm_events(UNEVICTABLE_PGRESCUED, nr_pages);
157 }
158 out:
159 if (isolated)
160 folio_set_lru(folio);
161 return lruvec;
162 }
163
164 /*
165 * Flags held in the low bits of a struct folio pointer on the mlock_fbatch.
166 */
167 #define LRU_FOLIO 0x1
168 #define NEW_FOLIO 0x2
169 static inline struct folio *mlock_lru(struct folio *folio)
170 {
171 return (struct folio *)((unsigned long)folio + LRU_FOLIO);
172 }
173
174 static inline struct folio *mlock_new(struct folio *folio)
175 {
176 return (struct folio *)((unsigned long)folio + NEW_FOLIO);
177 }
178
179 /*
180 * mlock_folio_batch() is derived from folio_batch_move_lru(): perhaps that can
181 * make use of such folio pointer flags in future, but for now just keep it for
182 * mlock. We could use three separate folio batches instead, but one feels
183 * better (munlocking a full folio batch does not need to drain mlocking folio
184 * batches first).
185 */
186 static void mlock_folio_batch(struct folio_batch *fbatch)
187 {
188 struct lruvec *lruvec = NULL;
189 unsigned long mlock;
190 struct folio *folio;
191 int i;
192
193 for (i = 0; i < folio_batch_count(fbatch); i++) {
194 folio = fbatch->folios[i];
195 mlock = (unsigned long)folio & (LRU_FOLIO | NEW_FOLIO);
196 folio = (struct folio *)((unsigned long)folio - mlock);
197 fbatch->folios[i] = folio;
198
199 if (mlock & LRU_FOLIO)
200 lruvec = __mlock_folio(folio, lruvec);
201 else if (mlock & NEW_FOLIO)
202 lruvec = __mlock_new_folio(folio, lruvec);
203 else
204 lruvec = __munlock_folio(folio, lruvec);
205 }
206
207 if (lruvec)
208 unlock_page_lruvec_irq(lruvec);
209 folios_put(fbatch);
210 }
211
212 void mlock_drain_local(void)
213 {
214 struct folio_batch *fbatch;
215
216 local_lock(&mlock_fbatch.lock);
217 fbatch = this_cpu_ptr(&mlock_fbatch.fbatch);
218 if (folio_batch_count(fbatch))
219 mlock_folio_batch(fbatch);
220 local_unlock(&mlock_fbatch.lock);
221 }
222
223 void mlock_drain_remote(int cpu)
224 {
225 struct folio_batch *fbatch;
226
227 WARN_ON_ONCE(cpu_online(cpu));
228 fbatch = &per_cpu(mlock_fbatch.fbatch, cpu);
229 if (folio_batch_count(fbatch))
230 mlock_folio_batch(fbatch);
231 }
232
233 bool need_mlock_drain(int cpu)
234 {
235 return folio_batch_count(&per_cpu(mlock_fbatch.fbatch, cpu));
236 }
237
238 /**
239 * mlock_folio - mlock a folio already on (or temporarily off) LRU
240 * @folio: folio to be mlocked.
241 */
242 void mlock_folio(struct folio *folio)
243 {
244 struct folio_batch *fbatch;
245
246 local_lock(&mlock_fbatch.lock);
247 fbatch = this_cpu_ptr(&mlock_fbatch.fbatch);
248
249 if (!folio_test_set_mlocked(folio)) {
250 int nr_pages = folio_nr_pages(folio);
251
252 zone_stat_mod_folio(folio, NR_MLOCK, nr_pages);
253 __count_vm_events(UNEVICTABLE_PGMLOCKED, nr_pages);
254 }
255
256 folio_get(folio);
257 if (!folio_batch_add(fbatch, mlock_lru(folio)) ||
258 folio_test_large(folio) || lru_cache_disabled())
259 mlock_folio_batch(fbatch);
260 local_unlock(&mlock_fbatch.lock);
261 }
262
263 /**
264 * mlock_new_folio - mlock a newly allocated folio not yet on LRU
265 * @folio: folio to be mlocked, either normal or a THP head.
266 */
267 void mlock_new_folio(struct folio *folio)
268 {
269 struct folio_batch *fbatch;
270 int nr_pages = folio_nr_pages(folio);
271
272 local_lock(&mlock_fbatch.lock);
273 fbatch = this_cpu_ptr(&mlock_fbatch.fbatch);
274 folio_set_mlocked(folio);
275
276 zone_stat_mod_folio(folio, NR_MLOCK, nr_pages);
277 __count_vm_events(UNEVICTABLE_PGMLOCKED, nr_pages);
278
279 folio_get(folio);
280 if (!folio_batch_add(fbatch, mlock_new(folio)) ||
281 folio_test_large(folio) || lru_cache_disabled())
282 mlock_folio_batch(fbatch);
283 local_unlock(&mlock_fbatch.lock);
284 }
285
286 /**
287 * munlock_folio - munlock a folio
288 * @folio: folio to be munlocked, either normal or a THP head.
289 */
290 void munlock_folio(struct folio *folio)
291 {
292 struct folio_batch *fbatch;
293
294 local_lock(&mlock_fbatch.lock);
295 fbatch = this_cpu_ptr(&mlock_fbatch.fbatch);
296 /*
297 * folio_test_clear_mlocked(folio) must be left to __munlock_folio(),
298 * which will check whether the folio is multiply mlocked.
299 */
300 folio_get(folio);
301 if (!folio_batch_add(fbatch, folio) ||
302 folio_test_large(folio) || lru_cache_disabled())
303 mlock_folio_batch(fbatch);
304 local_unlock(&mlock_fbatch.lock);
305 }
306
307 static inline unsigned int folio_mlock_step(struct folio *folio,
308 pte_t *pte, unsigned long addr, unsigned long end)
309 {
310 const fpb_t fpb_flags = FPB_IGNORE_DIRTY | FPB_IGNORE_SOFT_DIRTY;
311 unsigned int count = (end - addr) >> PAGE_SHIFT;
312 pte_t ptent = ptep_get(pte);
313
314 if (!folio_test_large(folio))
315 return 1;
316
317 return folio_pte_batch(folio, addr, pte, ptent, count, fpb_flags, NULL,
318 NULL, NULL);
319 }
320
321 static inline bool allow_mlock_munlock(struct folio *folio,
322 struct vm_area_struct *vma, unsigned long start,
323 unsigned long end, unsigned int step)
324 {
325 /*
326 * For unlock, allow munlock large folio which is partially
327 * mapped to VMA. As it's possible that large folio is
328 * mlocked and VMA is split later.
329 *
330 * During memory pressure, such kind of large folio can
331 * be split. And the pages are not in VM_LOCKed VMA
332 * can be reclaimed.
333 */
334 if (!(vma->vm_flags & VM_LOCKED))
335 return true;
336
337 /* folio_within_range() cannot take KSM, but any small folio is OK */
338 if (!folio_test_large(folio))
339 return true;
340
341 /* folio not in range [start, end), skip mlock */
342 if (!folio_within_range(folio, vma, start, end))
343 return false;
344
345 /* folio is not fully mapped, skip mlock */
346 if (step != folio_nr_pages(folio))
347 return false;
348
349 return true;
350 }
351
352 static int mlock_pte_range(pmd_t *pmd, unsigned long addr,
353 unsigned long end, struct mm_walk *walk)
354
355 {
356 struct vm_area_struct *vma = walk->vma;
357 spinlock_t *ptl;
358 pte_t *start_pte, *pte;
359 pte_t ptent;
360 struct folio *folio;
361 unsigned int step = 1;
362 unsigned long start = addr;
363
364 ptl = pmd_trans_huge_lock(pmd, vma);
365 if (ptl) {
366 if (!pmd_present(*pmd))
367 goto out;
368 if (is_huge_zero_pmd(*pmd))
369 goto out;
370 folio = pmd_folio(*pmd);
371 if (vma->vm_flags & VM_LOCKED)
372 mlock_folio(folio);
373 else
374 munlock_folio(folio);
375 goto out;
376 }
377
378 start_pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
379 if (!start_pte) {
380 walk->action = ACTION_AGAIN;
381 return 0;
382 }
383
384 for (pte = start_pte; addr != end; pte++, addr += PAGE_SIZE) {
385 ptent = ptep_get(pte);
386 if (!pte_present(ptent))
387 continue;
388 folio = vm_normal_folio(vma, addr, ptent);
389 if (!folio || folio_is_zone_device(folio))
390 continue;
391
392 step = folio_mlock_step(folio, pte, addr, end);
393 if (!allow_mlock_munlock(folio, vma, start, end, step))
394 goto next_entry;
395
396 if (vma->vm_flags & VM_LOCKED)
397 mlock_folio(folio);
398 else
399 munlock_folio(folio);
400
401 next_entry:
402 pte += step - 1;
403 addr += (step - 1) << PAGE_SHIFT;
404 }
405 pte_unmap(start_pte);
406 out:
407 spin_unlock(ptl);
408 cond_resched();
409 return 0;
410 }
411
412 /*
413 * mlock_vma_pages_range() - mlock any pages already in the range,
414 * or munlock all pages in the range.
415 * @vma - vma containing range to be mlock()ed or munlock()ed
416 * @start - start address in @vma of the range
417 * @end - end of range in @vma
418 * @newflags - the new set of flags for @vma.
419 *
420 * Called for mlock(), mlock2() and mlockall(), to set @vma VM_LOCKED;
421 * called for munlock() and munlockall(), to clear VM_LOCKED from @vma.
422 */
423 static void mlock_vma_pages_range(struct vm_area_struct *vma,
424 unsigned long start, unsigned long end, vm_flags_t newflags)
425 {
426 static const struct mm_walk_ops mlock_walk_ops = {
427 .pmd_entry = mlock_pte_range,
428 .walk_lock = PGWALK_WRLOCK_VERIFY,
429 };
430
431 /*
432 * There is a slight chance that concurrent page migration,
433 * or page reclaim finding a page of this now-VM_LOCKED vma,
434 * will call mlock_vma_folio() and raise page's mlock_count:
435 * double counting, leaving the page unevictable indefinitely.
436 * Communicate this danger to mlock_vma_folio() with VM_IO,
437 * which is a VM_SPECIAL flag not allowed on VM_LOCKED vmas.
438 * mmap_lock is held in write mode here, so this weird
439 * combination should not be visible to other mmap_lock users;
440 * but WRITE_ONCE so rmap walkers must see VM_IO if VM_LOCKED.
441 */
442 if (newflags & VM_LOCKED)
443 newflags |= VM_IO;
444 vma_start_write(vma);
445 vm_flags_reset_once(vma, newflags);
446
447 lru_add_drain();
448 walk_page_range(vma->vm_mm, start, end, &mlock_walk_ops, NULL);
449 lru_add_drain();
450
451 if (newflags & VM_IO) {
452 newflags &= ~VM_IO;
453 vm_flags_reset_once(vma, newflags);
454 }
455 }
456
457 /*
458 * mlock_fixup - handle mlock[all]/munlock[all] requests.
459 *
460 * Filters out "special" vmas -- VM_LOCKED never gets set for these, and
461 * munlock is a no-op. However, for some special vmas, we go ahead and
462 * populate the ptes.
463 *
464 * For vmas that pass the filters, merge/split as appropriate.
465 */
466 static int mlock_fixup(struct vma_iterator *vmi, struct vm_area_struct *vma,
467 struct vm_area_struct **prev, unsigned long start,
468 unsigned long end, vm_flags_t newflags)
469 {
470 struct mm_struct *mm = vma->vm_mm;
471 int nr_pages;
472 int ret = 0;
473 vm_flags_t oldflags = vma->vm_flags;
474
475 if (newflags == oldflags || (oldflags & VM_SPECIAL) ||
476 is_vm_hugetlb_page(vma) || vma == get_gate_vma(current->mm) ||
477 vma_is_dax(vma) || vma_is_secretmem(vma) || (oldflags & VM_DROPPABLE))
478 /* don't set VM_LOCKED or VM_LOCKONFAULT and don't count */
479 goto out;
480
481 vma = vma_modify_flags(vmi, *prev, vma, start, end, newflags);
482 if (IS_ERR(vma)) {
483 ret = PTR_ERR(vma);
484 goto out;
485 }
486
487 /*
488 * Keep track of amount of locked VM.
489 */
490 nr_pages = (end - start) >> PAGE_SHIFT;
491 if (!(newflags & VM_LOCKED))
492 nr_pages = -nr_pages;
493 else if (oldflags & VM_LOCKED)
494 nr_pages = 0;
495 mm->locked_vm += nr_pages;
496
497 /*
498 * vm_flags is protected by the mmap_lock held in write mode.
499 * It's okay if try_to_unmap_one unmaps a page just after we
500 * set VM_LOCKED, populate_vma_page_range will bring it back.
501 */
502 if ((newflags & VM_LOCKED) && (oldflags & VM_LOCKED)) {
503 /* No work to do, and mlocking twice would be wrong */
504 vma_start_write(vma);
505 vm_flags_reset(vma, newflags);
506 } else {
507 mlock_vma_pages_range(vma, start, end, newflags);
508 }
509 out:
510 *prev = vma;
511 return ret;
512 }
513
514 static int apply_vma_lock_flags(unsigned long start, size_t len,
515 vm_flags_t flags)
516 {
517 unsigned long nstart, end, tmp;
518 struct vm_area_struct *vma, *prev;
519 VMA_ITERATOR(vmi, current->mm, start);
520
521 VM_BUG_ON(offset_in_page(start));
522 VM_BUG_ON(len != PAGE_ALIGN(len));
523 end = start + len;
524 if (end < start)
525 return -EINVAL;
526 if (end == start)
527 return 0;
528 vma = vma_iter_load(&vmi);
529 if (!vma)
530 return -ENOMEM;
531
532 prev = vma_prev(&vmi);
533 if (start > vma->vm_start)
534 prev = vma;
535
536 nstart = start;
537 tmp = vma->vm_start;
538 for_each_vma_range(vmi, vma, end) {
539 int error;
540 vm_flags_t newflags;
541
542 if (vma->vm_start != tmp)
543 return -ENOMEM;
544
545 newflags = vma->vm_flags & ~VM_LOCKED_MASK;
546 newflags |= flags;
547 /* Here we know that vma->vm_start <= nstart < vma->vm_end. */
548 tmp = vma->vm_end;
549 if (tmp > end)
550 tmp = end;
551 error = mlock_fixup(&vmi, vma, &prev, nstart, tmp, newflags);
552 if (error)
553 return error;
554 tmp = vma_iter_end(&vmi);
555 nstart = tmp;
556 }
557
558 if (tmp < end)
559 return -ENOMEM;
560
561 return 0;
562 }
563
564 /*
565 * Go through vma areas and sum size of mlocked
566 * vma pages, as return value.
567 * Note deferred memory locking case(mlock2(,,MLOCK_ONFAULT)
568 * is also counted.
569 * Return value: previously mlocked page counts
570 */
571 static unsigned long count_mm_mlocked_page_nr(struct mm_struct *mm,
572 unsigned long start, size_t len)
573 {
574 struct vm_area_struct *vma;
575 unsigned long count = 0;
576 unsigned long end;
577 VMA_ITERATOR(vmi, mm, start);
578
579 /* Don't overflow past ULONG_MAX */
580 if (unlikely(ULONG_MAX - len < start))
581 end = ULONG_MAX;
582 else
583 end = start + len;
584
585 for_each_vma_range(vmi, vma, end) {
586 if (vma->vm_flags & VM_LOCKED) {
587 if (start > vma->vm_start)
588 count -= (start - vma->vm_start);
589 if (end < vma->vm_end) {
590 count += end - vma->vm_start;
591 break;
592 }
593 count += vma->vm_end - vma->vm_start;
594 }
595 }
596
597 return count >> PAGE_SHIFT;
598 }
599
600 /*
601 * convert get_user_pages() return value to posix mlock() error
602 */
603 static int __mlock_posix_error_return(long retval)
604 {
605 if (retval == -EFAULT)
606 retval = -ENOMEM;
607 else if (retval == -ENOMEM)
608 retval = -EAGAIN;
609 return retval;
610 }
611
612 static __must_check int do_mlock(unsigned long start, size_t len, vm_flags_t flags)
613 {
614 unsigned long locked;
615 unsigned long lock_limit;
616 int error = -ENOMEM;
617
618 start = untagged_addr(start);
619
620 if (!can_do_mlock())
621 return -EPERM;
622
623 len = PAGE_ALIGN(len + (offset_in_page(start)));
624 start &= PAGE_MASK;
625
626 lock_limit = rlimit(RLIMIT_MEMLOCK);
627 lock_limit >>= PAGE_SHIFT;
628 locked = len >> PAGE_SHIFT;
629
630 if (mmap_write_lock_killable(current->mm))
631 return -EINTR;
632
633 locked += current->mm->locked_vm;
634 if ((locked > lock_limit) && (!capable(CAP_IPC_LOCK))) {
635 /*
636 * It is possible that the regions requested intersect with
637 * previously mlocked areas, that part area in "mm->locked_vm"
638 * should not be counted to new mlock increment count. So check
639 * and adjust locked count if necessary.
640 */
641 locked -= count_mm_mlocked_page_nr(current->mm,
642 start, len);
643 }
644
645 /* check against resource limits */
646 if ((locked <= lock_limit) || capable(CAP_IPC_LOCK))
647 error = apply_vma_lock_flags(start, len, flags);
648
649 mmap_write_unlock(current->mm);
650 if (error)
651 return error;
652
653 error = __mm_populate(start, len, 0);
654 if (error)
655 return __mlock_posix_error_return(error);
656 return 0;
657 }
658
659 SYSCALL_DEFINE2(mlock, unsigned long, start, size_t, len)
660 {
661 return do_mlock(start, len, VM_LOCKED);
662 }
663
664 SYSCALL_DEFINE3(mlock2, unsigned long, start, size_t, len, int, flags)
665 {
666 vm_flags_t vm_flags = VM_LOCKED;
667
668 if (flags & ~MLOCK_ONFAULT)
669 return -EINVAL;
670
671 if (flags & MLOCK_ONFAULT)
672 vm_flags |= VM_LOCKONFAULT;
673
674 return do_mlock(start, len, vm_flags);
675 }
676
677 SYSCALL_DEFINE2(munlock, unsigned long, start, size_t, len)
678 {
679 int ret;
680
681 start = untagged_addr(start);
682
683 len = PAGE_ALIGN(len + (offset_in_page(start)));
684 start &= PAGE_MASK;
685
686 if (mmap_write_lock_killable(current->mm))
687 return -EINTR;
688 ret = apply_vma_lock_flags(start, len, 0);
689 mmap_write_unlock(current->mm);
690
691 return ret;
692 }
693
694 /*
695 * Take the MCL_* flags passed into mlockall (or 0 if called from munlockall)
696 * and translate into the appropriate modifications to mm->def_flags and/or the
697 * flags for all current VMAs.
698 *
699 * There are a couple of subtleties with this. If mlockall() is called multiple
700 * times with different flags, the values do not necessarily stack. If mlockall
701 * is called once including the MCL_FUTURE flag and then a second time without
702 * it, VM_LOCKED and VM_LOCKONFAULT will be cleared from mm->def_flags.
703 */
704 static int apply_mlockall_flags(int flags)
705 {
706 VMA_ITERATOR(vmi, current->mm, 0);
707 struct vm_area_struct *vma, *prev = NULL;
708 vm_flags_t to_add = 0;
709
710 current->mm->def_flags &= ~VM_LOCKED_MASK;
711 if (flags & MCL_FUTURE) {
712 current->mm->def_flags |= VM_LOCKED;
713
714 if (flags & MCL_ONFAULT)
715 current->mm->def_flags |= VM_LOCKONFAULT;
716
717 if (!(flags & MCL_CURRENT))
718 goto out;
719 }
720
721 if (flags & MCL_CURRENT) {
722 to_add |= VM_LOCKED;
723 if (flags & MCL_ONFAULT)
724 to_add |= VM_LOCKONFAULT;
725 }
726
727 for_each_vma(vmi, vma) {
728 vm_flags_t newflags;
729
730 newflags = vma->vm_flags & ~VM_LOCKED_MASK;
731 newflags |= to_add;
732
733 /* Ignore errors */
734 mlock_fixup(&vmi, vma, &prev, vma->vm_start, vma->vm_end,
735 newflags);
736 cond_resched();
737 }
738 out:
739 return 0;
740 }
741
742 SYSCALL_DEFINE1(mlockall, int, flags)
743 {
744 unsigned long lock_limit;
745 int ret;
746
747 if (!flags || (flags & ~(MCL_CURRENT | MCL_FUTURE | MCL_ONFAULT)) ||
748 flags == MCL_ONFAULT)
749 return -EINVAL;
750
751 if (!can_do_mlock())
752 return -EPERM;
753
754 lock_limit = rlimit(RLIMIT_MEMLOCK);
755 lock_limit >>= PAGE_SHIFT;
756
757 if (mmap_write_lock_killable(current->mm))
758 return -EINTR;
759
760 ret = -ENOMEM;
761 if (!(flags & MCL_CURRENT) || (current->mm->total_vm <= lock_limit) ||
762 capable(CAP_IPC_LOCK))
763 ret = apply_mlockall_flags(flags);
764 mmap_write_unlock(current->mm);
765 if (!ret && (flags & MCL_CURRENT))
766 mm_populate(0, TASK_SIZE);
767
768 return ret;
769 }
770
771 SYSCALL_DEFINE0(munlockall)
772 {
773 int ret;
774
775 if (mmap_write_lock_killable(current->mm))
776 return -EINTR;
777 ret = apply_mlockall_flags(0);
778 mmap_write_unlock(current->mm);
779 return ret;
780 }
781
782 /*
783 * Objects with different lifetime than processes (SHM_LOCK and SHM_HUGETLB
784 * shm segments) get accounted against the user_struct instead.
785 */
786 static DEFINE_SPINLOCK(shmlock_user_lock);
787
788 int user_shm_lock(size_t size, struct ucounts *ucounts)
789 {
790 unsigned long lock_limit, locked;
791 long memlock;
792 int allowed = 0;
793
794 locked = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
795 lock_limit = rlimit(RLIMIT_MEMLOCK);
796 if (lock_limit != RLIM_INFINITY)
797 lock_limit >>= PAGE_SHIFT;
798 spin_lock(&shmlock_user_lock);
799 memlock = inc_rlimit_ucounts(ucounts, UCOUNT_RLIMIT_MEMLOCK, locked);
800
801 if ((memlock == LONG_MAX || memlock > lock_limit) && !capable(CAP_IPC_LOCK)) {
802 dec_rlimit_ucounts(ucounts, UCOUNT_RLIMIT_MEMLOCK, locked);
803 goto out;
804 }
805 if (!get_ucounts(ucounts)) {
806 dec_rlimit_ucounts(ucounts, UCOUNT_RLIMIT_MEMLOCK, locked);
807 allowed = 0;
808 goto out;
809 }
810 allowed = 1;
811 out:
812 spin_unlock(&shmlock_user_lock);
813 return allowed;
814 }
815
816 void user_shm_unlock(size_t size, struct ucounts *ucounts)
817 {
818 spin_lock(&shmlock_user_lock);
819 dec_rlimit_ucounts(ucounts, UCOUNT_RLIMIT_MEMLOCK, (size + PAGE_SIZE - 1) >> PAGE_SHIFT);
820 spin_unlock(&shmlock_user_lock);
821 put_ucounts(ucounts);
822 }
823
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