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8#include <linux/capability.h>
9#include <linux/mman.h>
10#include <linux/mm.h>
11#include <linux/sched/user.h>
12#include <linux/swap.h>
13#include <linux/swapops.h>
14#include <linux/pagemap.h>
15#include <linux/pagevec.h>
16#include <linux/mempolicy.h>
17#include <linux/syscalls.h>
18#include <linux/sched.h>
19#include <linux/export.h>
20#include <linux/rmap.h>
21#include <linux/mmzone.h>
22#include <linux/hugetlb.h>
23#include <linux/memcontrol.h>
24#include <linux/mm_inline.h>
25
26#include "internal.h"
27
28bool can_do_mlock(void)
29{
30 if (rlimit(RLIMIT_MEMLOCK) != 0)
31 return true;
32 if (capable(CAP_IPC_LOCK))
33 return true;
34 return false;
35}
36EXPORT_SYMBOL(can_do_mlock);
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58void clear_page_mlock(struct page *page)
59{
60 if (!TestClearPageMlocked(page))
61 return;
62
63 mod_zone_page_state(page_zone(page), NR_MLOCK,
64 -hpage_nr_pages(page));
65 count_vm_event(UNEVICTABLE_PGCLEARED);
66 if (!isolate_lru_page(page)) {
67 putback_lru_page(page);
68 } else {
69
70
71
72 if (PageUnevictable(page))
73 count_vm_event(UNEVICTABLE_PGSTRANDED);
74 }
75}
76
77
78
79
80
81void mlock_vma_page(struct page *page)
82{
83
84 BUG_ON(!PageLocked(page));
85
86 VM_BUG_ON_PAGE(PageTail(page), page);
87 VM_BUG_ON_PAGE(PageCompound(page) && PageDoubleMap(page), page);
88
89 if (!TestSetPageMlocked(page)) {
90 mod_zone_page_state(page_zone(page), NR_MLOCK,
91 hpage_nr_pages(page));
92 count_vm_event(UNEVICTABLE_PGMLOCKED);
93 if (!isolate_lru_page(page))
94 putback_lru_page(page);
95 }
96}
97
98
99
100
101
102static bool __munlock_isolate_lru_page(struct page *page, bool getpage)
103{
104 if (PageLRU(page)) {
105 struct lruvec *lruvec;
106
107 lruvec = mem_cgroup_page_lruvec(page, page_pgdat(page));
108 if (getpage)
109 get_page(page);
110 ClearPageLRU(page);
111 del_page_from_lru_list(page, lruvec, page_lru(page));
112 return true;
113 }
114
115 return false;
116}
117
118
119
120
121
122
123
124static void __munlock_isolated_page(struct page *page)
125{
126
127
128
129
130 if (page_mapcount(page) > 1)
131 try_to_munlock(page);
132
133
134 if (!PageMlocked(page))
135 count_vm_event(UNEVICTABLE_PGMUNLOCKED);
136
137 putback_lru_page(page);
138}
139
140
141
142
143
144
145
146
147
148
149static void __munlock_isolation_failed(struct page *page)
150{
151 if (PageUnevictable(page))
152 __count_vm_event(UNEVICTABLE_PGSTRANDED);
153 else
154 __count_vm_event(UNEVICTABLE_PGMUNLOCKED);
155}
156
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172
173
174
175unsigned int munlock_vma_page(struct page *page)
176{
177 int nr_pages;
178 struct zone *zone = page_zone(page);
179
180
181 BUG_ON(!PageLocked(page));
182
183 VM_BUG_ON_PAGE(PageTail(page), page);
184
185
186
187
188
189
190 spin_lock_irq(zone_lru_lock(zone));
191
192 if (!TestClearPageMlocked(page)) {
193
194 nr_pages = 1;
195 goto unlock_out;
196 }
197
198 nr_pages = hpage_nr_pages(page);
199 __mod_zone_page_state(zone, NR_MLOCK, -nr_pages);
200
201 if (__munlock_isolate_lru_page(page, true)) {
202 spin_unlock_irq(zone_lru_lock(zone));
203 __munlock_isolated_page(page);
204 goto out;
205 }
206 __munlock_isolation_failed(page);
207
208unlock_out:
209 spin_unlock_irq(zone_lru_lock(zone));
210
211out:
212 return nr_pages - 1;
213}
214
215
216
217
218static int __mlock_posix_error_return(long retval)
219{
220 if (retval == -EFAULT)
221 retval = -ENOMEM;
222 else if (retval == -ENOMEM)
223 retval = -EAGAIN;
224 return retval;
225}
226
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237
238
239static bool __putback_lru_fast_prepare(struct page *page, struct pagevec *pvec,
240 int *pgrescued)
241{
242 VM_BUG_ON_PAGE(PageLRU(page), page);
243 VM_BUG_ON_PAGE(!PageLocked(page), page);
244
245 if (page_mapcount(page) <= 1 && page_evictable(page)) {
246 pagevec_add(pvec, page);
247 if (TestClearPageUnevictable(page))
248 (*pgrescued)++;
249 unlock_page(page);
250 return true;
251 }
252
253 return false;
254}
255
256
257
258
259
260
261
262static void __putback_lru_fast(struct pagevec *pvec, int pgrescued)
263{
264 count_vm_events(UNEVICTABLE_PGMUNLOCKED, pagevec_count(pvec));
265
266
267
268
269 __pagevec_lru_add(pvec);
270 count_vm_events(UNEVICTABLE_PGRESCUED, pgrescued);
271}
272
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279
280
281
282
283static void __munlock_pagevec(struct pagevec *pvec, struct zone *zone)
284{
285 int i;
286 int nr = pagevec_count(pvec);
287 int delta_munlocked = -nr;
288 struct pagevec pvec_putback;
289 int pgrescued = 0;
290
291 pagevec_init(&pvec_putback, 0);
292
293
294 spin_lock_irq(zone_lru_lock(zone));
295 for (i = 0; i < nr; i++) {
296 struct page *page = pvec->pages[i];
297
298 if (TestClearPageMlocked(page)) {
299
300
301
302
303 if (__munlock_isolate_lru_page(page, false))
304 continue;
305 else
306 __munlock_isolation_failed(page);
307 } else {
308 delta_munlocked++;
309 }
310
311
312
313
314
315
316
317 pagevec_add(&pvec_putback, pvec->pages[i]);
318 pvec->pages[i] = NULL;
319 }
320 __mod_zone_page_state(zone, NR_MLOCK, delta_munlocked);
321 spin_unlock_irq(zone_lru_lock(zone));
322
323
324 pagevec_release(&pvec_putback);
325
326
327 for (i = 0; i < nr; i++) {
328 struct page *page = pvec->pages[i];
329
330 if (page) {
331 lock_page(page);
332 if (!__putback_lru_fast_prepare(page, &pvec_putback,
333 &pgrescued)) {
334
335
336
337
338 get_page(page);
339 __munlock_isolated_page(page);
340 unlock_page(page);
341 put_page(page);
342 }
343 }
344 }
345
346
347
348
349
350 if (pagevec_count(&pvec_putback))
351 __putback_lru_fast(&pvec_putback, pgrescued);
352}
353
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365
366
367static unsigned long __munlock_pagevec_fill(struct pagevec *pvec,
368 struct vm_area_struct *vma, int zoneid, unsigned long start,
369 unsigned long end)
370{
371 pte_t *pte;
372 spinlock_t *ptl;
373
374
375
376
377
378
379 pte = get_locked_pte(vma->vm_mm, start, &ptl);
380
381 end = pgd_addr_end(start, end);
382 end = p4d_addr_end(start, end);
383 end = pud_addr_end(start, end);
384 end = pmd_addr_end(start, end);
385
386
387 start += PAGE_SIZE;
388 while (start < end) {
389 struct page *page = NULL;
390 pte++;
391 if (pte_present(*pte))
392 page = vm_normal_page(vma, start, *pte);
393
394
395
396
397 if (!page || page_zone_id(page) != zoneid)
398 break;
399
400
401
402
403
404 if (PageTransCompound(page))
405 break;
406
407 get_page(page);
408
409
410
411
412 start += PAGE_SIZE;
413 if (pagevec_add(pvec, page) == 0)
414 break;
415 }
416 pte_unmap_unlock(pte, ptl);
417 return start;
418}
419
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436
437
438void munlock_vma_pages_range(struct vm_area_struct *vma,
439 unsigned long start, unsigned long end)
440{
441 vma->vm_flags &= VM_LOCKED_CLEAR_MASK;
442
443 while (start < end) {
444 struct page *page;
445 unsigned int page_mask = 0;
446 unsigned long page_increm;
447 struct pagevec pvec;
448 struct zone *zone;
449 int zoneid;
450
451 pagevec_init(&pvec, 0);
452
453
454
455
456
457
458
459 page = follow_page(vma, start, FOLL_GET | FOLL_DUMP);
460
461 if (page && !IS_ERR(page)) {
462 if (PageTransTail(page)) {
463 VM_BUG_ON_PAGE(PageMlocked(page), page);
464 put_page(page);
465 } else if (PageTransHuge(page)) {
466 lock_page(page);
467
468
469
470
471
472
473 page_mask = munlock_vma_page(page);
474 unlock_page(page);
475 put_page(page);
476 } else {
477
478
479
480
481
482 pagevec_add(&pvec, page);
483 zone = page_zone(page);
484 zoneid = page_zone_id(page);
485
486
487
488
489
490
491
492 start = __munlock_pagevec_fill(&pvec, vma,
493 zoneid, start, end);
494 __munlock_pagevec(&pvec, zone);
495 goto next;
496 }
497 }
498 page_increm = 1 + page_mask;
499 start += page_increm * PAGE_SIZE;
500next:
501 cond_resched();
502 }
503}
504
505
506
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508
509
510
511
512
513
514static int mlock_fixup(struct vm_area_struct *vma, struct vm_area_struct **prev,
515 unsigned long start, unsigned long end, vm_flags_t newflags)
516{
517 struct mm_struct *mm = vma->vm_mm;
518 pgoff_t pgoff;
519 int nr_pages;
520 int ret = 0;
521 int lock = !!(newflags & VM_LOCKED);
522 vm_flags_t old_flags = vma->vm_flags;
523
524 if (newflags == vma->vm_flags || (vma->vm_flags & VM_SPECIAL) ||
525 is_vm_hugetlb_page(vma) || vma == get_gate_vma(current->mm))
526
527 goto out;
528
529 pgoff = vma->vm_pgoff + ((start - vma->vm_start) >> PAGE_SHIFT);
530 *prev = vma_merge(mm, *prev, start, end, newflags, vma->anon_vma,
531 vma->vm_file, pgoff, vma_policy(vma),
532 vma->vm_userfaultfd_ctx);
533 if (*prev) {
534 vma = *prev;
535 goto success;
536 }
537
538 if (start != vma->vm_start) {
539 ret = split_vma(mm, vma, start, 1);
540 if (ret)
541 goto out;
542 }
543
544 if (end != vma->vm_end) {
545 ret = split_vma(mm, vma, end, 0);
546 if (ret)
547 goto out;
548 }
549
550success:
551
552
553
554 nr_pages = (end - start) >> PAGE_SHIFT;
555 if (!lock)
556 nr_pages = -nr_pages;
557 else if (old_flags & VM_LOCKED)
558 nr_pages = 0;
559 mm->locked_vm += nr_pages;
560
561
562
563
564
565
566
567 if (lock)
568 vma->vm_flags = newflags;
569 else
570 munlock_vma_pages_range(vma, start, end);
571
572out:
573 *prev = vma;
574 return ret;
575}
576
577static int apply_vma_lock_flags(unsigned long start, size_t len,
578 vm_flags_t flags)
579{
580 unsigned long nstart, end, tmp;
581 struct vm_area_struct * vma, * prev;
582 int error;
583
584 VM_BUG_ON(offset_in_page(start));
585 VM_BUG_ON(len != PAGE_ALIGN(len));
586 end = start + len;
587 if (end < start)
588 return -EINVAL;
589 if (end == start)
590 return 0;
591 vma = find_vma(current->mm, start);
592 if (!vma || vma->vm_start > start)
593 return -ENOMEM;
594
595 prev = vma->vm_prev;
596 if (start > vma->vm_start)
597 prev = vma;
598
599 for (nstart = start ; ; ) {
600 vm_flags_t newflags = vma->vm_flags & VM_LOCKED_CLEAR_MASK;
601
602 newflags |= flags;
603
604
605 tmp = vma->vm_end;
606 if (tmp > end)
607 tmp = end;
608 error = mlock_fixup(vma, &prev, nstart, tmp, newflags);
609 if (error)
610 break;
611 nstart = tmp;
612 if (nstart < prev->vm_end)
613 nstart = prev->vm_end;
614 if (nstart >= end)
615 break;
616
617 vma = prev->vm_next;
618 if (!vma || vma->vm_start != nstart) {
619 error = -ENOMEM;
620 break;
621 }
622 }
623 return error;
624}
625
626
627
628
629
630
631
632
633static int count_mm_mlocked_page_nr(struct mm_struct *mm,
634 unsigned long start, size_t len)
635{
636 struct vm_area_struct *vma;
637 int count = 0;
638
639 if (mm == NULL)
640 mm = current->mm;
641
642 vma = find_vma(mm, start);
643 if (vma == NULL)
644 vma = mm->mmap;
645
646 for (; vma ; vma = vma->vm_next) {
647 if (start >= vma->vm_end)
648 continue;
649 if (start + len <= vma->vm_start)
650 break;
651 if (vma->vm_flags & VM_LOCKED) {
652 if (start > vma->vm_start)
653 count -= (start - vma->vm_start);
654 if (start + len < vma->vm_end) {
655 count += start + len - vma->vm_start;
656 break;
657 }
658 count += vma->vm_end - vma->vm_start;
659 }
660 }
661
662 return count >> PAGE_SHIFT;
663}
664
665static __must_check int do_mlock(unsigned long start, size_t len, vm_flags_t flags)
666{
667 unsigned long locked;
668 unsigned long lock_limit;
669 int error = -ENOMEM;
670
671 if (!can_do_mlock())
672 return -EPERM;
673
674 lru_add_drain_all();
675
676 len = PAGE_ALIGN(len + (offset_in_page(start)));
677 start &= PAGE_MASK;
678
679 lock_limit = rlimit(RLIMIT_MEMLOCK);
680 lock_limit >>= PAGE_SHIFT;
681 locked = len >> PAGE_SHIFT;
682
683 if (down_write_killable(¤t->mm->mmap_sem))
684 return -EINTR;
685
686 locked += current->mm->locked_vm;
687 if ((locked > lock_limit) && (!capable(CAP_IPC_LOCK))) {
688
689
690
691
692
693
694 locked -= count_mm_mlocked_page_nr(current->mm,
695 start, len);
696 }
697
698
699 if ((locked <= lock_limit) || capable(CAP_IPC_LOCK))
700 error = apply_vma_lock_flags(start, len, flags);
701
702 up_write(¤t->mm->mmap_sem);
703 if (error)
704 return error;
705
706 error = __mm_populate(start, len, 0);
707 if (error)
708 return __mlock_posix_error_return(error);
709 return 0;
710}
711
712SYSCALL_DEFINE2(mlock, unsigned long, start, size_t, len)
713{
714 return do_mlock(start, len, VM_LOCKED);
715}
716
717SYSCALL_DEFINE3(mlock2, unsigned long, start, size_t, len, int, flags)
718{
719 vm_flags_t vm_flags = VM_LOCKED;
720
721 if (flags & ~MLOCK_ONFAULT)
722 return -EINVAL;
723
724 if (flags & MLOCK_ONFAULT)
725 vm_flags |= VM_LOCKONFAULT;
726
727 return do_mlock(start, len, vm_flags);
728}
729
730SYSCALL_DEFINE2(munlock, unsigned long, start, size_t, len)
731{
732 int ret;
733
734 len = PAGE_ALIGN(len + (offset_in_page(start)));
735 start &= PAGE_MASK;
736
737 if (down_write_killable(¤t->mm->mmap_sem))
738 return -EINTR;
739 ret = apply_vma_lock_flags(start, len, 0);
740 up_write(¤t->mm->mmap_sem);
741
742 return ret;
743}
744
745
746
747
748
749
750
751
752
753
754
755static int apply_mlockall_flags(int flags)
756{
757 struct vm_area_struct * vma, * prev = NULL;
758 vm_flags_t to_add = 0;
759
760 current->mm->def_flags &= VM_LOCKED_CLEAR_MASK;
761 if (flags & MCL_FUTURE) {
762 current->mm->def_flags |= VM_LOCKED;
763
764 if (flags & MCL_ONFAULT)
765 current->mm->def_flags |= VM_LOCKONFAULT;
766
767 if (!(flags & MCL_CURRENT))
768 goto out;
769 }
770
771 if (flags & MCL_CURRENT) {
772 to_add |= VM_LOCKED;
773 if (flags & MCL_ONFAULT)
774 to_add |= VM_LOCKONFAULT;
775 }
776
777 for (vma = current->mm->mmap; vma ; vma = prev->vm_next) {
778 vm_flags_t newflags;
779
780 newflags = vma->vm_flags & VM_LOCKED_CLEAR_MASK;
781 newflags |= to_add;
782
783
784 mlock_fixup(vma, &prev, vma->vm_start, vma->vm_end, newflags);
785 cond_resched_rcu_qs();
786 }
787out:
788 return 0;
789}
790
791SYSCALL_DEFINE1(mlockall, int, flags)
792{
793 unsigned long lock_limit;
794 int ret;
795
796 if (!flags || (flags & ~(MCL_CURRENT | MCL_FUTURE | MCL_ONFAULT)))
797 return -EINVAL;
798
799 if (!can_do_mlock())
800 return -EPERM;
801
802 if (flags & MCL_CURRENT)
803 lru_add_drain_all();
804
805 lock_limit = rlimit(RLIMIT_MEMLOCK);
806 lock_limit >>= PAGE_SHIFT;
807
808 if (down_write_killable(¤t->mm->mmap_sem))
809 return -EINTR;
810
811 ret = -ENOMEM;
812 if (!(flags & MCL_CURRENT) || (current->mm->total_vm <= lock_limit) ||
813 capable(CAP_IPC_LOCK))
814 ret = apply_mlockall_flags(flags);
815 up_write(¤t->mm->mmap_sem);
816 if (!ret && (flags & MCL_CURRENT))
817 mm_populate(0, TASK_SIZE);
818
819 return ret;
820}
821
822SYSCALL_DEFINE0(munlockall)
823{
824 int ret;
825
826 if (down_write_killable(¤t->mm->mmap_sem))
827 return -EINTR;
828 ret = apply_mlockall_flags(0);
829 up_write(¤t->mm->mmap_sem);
830 return ret;
831}
832
833
834
835
836
837static DEFINE_SPINLOCK(shmlock_user_lock);
838
839int user_shm_lock(size_t size, struct user_struct *user)
840{
841 unsigned long lock_limit, locked;
842 int allowed = 0;
843
844 locked = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
845 lock_limit = rlimit(RLIMIT_MEMLOCK);
846 if (lock_limit == RLIM_INFINITY)
847 allowed = 1;
848 lock_limit >>= PAGE_SHIFT;
849 spin_lock(&shmlock_user_lock);
850 if (!allowed &&
851 locked + user->locked_shm > lock_limit && !capable(CAP_IPC_LOCK))
852 goto out;
853 get_uid(user);
854 user->locked_shm += locked;
855 allowed = 1;
856out:
857 spin_unlock(&shmlock_user_lock);
858 return allowed;
859}
860
861void user_shm_unlock(size_t size, struct user_struct *user)
862{
863 spin_lock(&shmlock_user_lock);
864 user->locked_shm -= (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
865 spin_unlock(&shmlock_user_lock);
866 free_uid(user);
867}
868