diff options
Diffstat (limited to '')
-rw-r--r-- | mm/mlock.c | 782 |
1 files changed, 343 insertions, 439 deletions
diff --git a/mm/mlock.c b/mm/mlock.c index a72c1eeded77..7032f6dd0ce1 100644 --- a/mm/mlock.c +++ b/mm/mlock.c @@ -14,6 +14,7 @@ #include <linux/swapops.h> #include <linux/pagemap.h> #include <linux/pagevec.h> +#include <linux/pagewalk.h> #include <linux/mempolicy.h> #include <linux/syscalls.h> #include <linux/sched.h> @@ -23,9 +24,19 @@ #include <linux/hugetlb.h> #include <linux/memcontrol.h> #include <linux/mm_inline.h> +#include <linux/secretmem.h> #include "internal.h" +struct mlock_pvec { + local_lock_t lock; + struct pagevec vec; +}; + +static DEFINE_PER_CPU(struct mlock_pvec, mlock_pvec) = { + .lock = INIT_LOCAL_LOCK(lock), +}; + bool can_do_mlock(void) { if (rlimit(RLIMIT_MEMLOCK) != 0) @@ -45,465 +56,339 @@ EXPORT_SYMBOL(can_do_mlock); * be placed on the LRU "unevictable" list, rather than the [in]active lists. * The unevictable list is an LRU sibling list to the [in]active lists. * PageUnevictable is set to indicate the unevictable state. - * - * When lazy mlocking via vmscan, it is important to ensure that the - * vma's VM_LOCKED status is not concurrently being modified, otherwise we - * may have mlocked a page that is being munlocked. So lazy mlock must take - * the mmap_sem for read, and verify that the vma really is locked - * (see mm/rmap.c). */ -/* - * LRU accounting for clear_page_mlock() - */ -void clear_page_mlock(struct page *page) +static struct lruvec *__mlock_page(struct page *page, struct lruvec *lruvec) { - if (!TestClearPageMlocked(page)) - return; + /* There is nothing more we can do while it's off LRU */ + if (!TestClearPageLRU(page)) + return lruvec; - mod_zone_page_state(page_zone(page), NR_MLOCK, - -hpage_nr_pages(page)); - count_vm_event(UNEVICTABLE_PGCLEARED); - /* - * The previous TestClearPageMlocked() corresponds to the smp_mb() - * in __pagevec_lru_add_fn(). - * - * See __pagevec_lru_add_fn for more explanation. - */ - if (!isolate_lru_page(page)) { - putback_lru_page(page); - } else { + lruvec = folio_lruvec_relock_irq(page_folio(page), lruvec); + + if (unlikely(page_evictable(page))) { /* - * We lost the race. the page already moved to evictable list. + * This is a little surprising, but quite possible: + * PageMlocked must have got cleared already by another CPU. + * Could this page be on the Unevictable LRU? I'm not sure, + * but move it now if so. */ - if (PageUnevictable(page)) - count_vm_event(UNEVICTABLE_PGSTRANDED); + if (PageUnevictable(page)) { + del_page_from_lru_list(page, lruvec); + ClearPageUnevictable(page); + add_page_to_lru_list(page, lruvec); + __count_vm_events(UNEVICTABLE_PGRESCUED, + thp_nr_pages(page)); + } + goto out; } -} -/* - * Mark page as mlocked if not already. - * If page on LRU, isolate and putback to move to unevictable list. - */ -void mlock_vma_page(struct page *page) -{ - /* Serialize with page migration */ - BUG_ON(!PageLocked(page)); - - VM_BUG_ON_PAGE(PageTail(page), page); - VM_BUG_ON_PAGE(PageCompound(page) && PageDoubleMap(page), page); - - if (!TestSetPageMlocked(page)) { - mod_zone_page_state(page_zone(page), NR_MLOCK, - hpage_nr_pages(page)); - count_vm_event(UNEVICTABLE_PGMLOCKED); - if (!isolate_lru_page(page)) - putback_lru_page(page); + if (PageUnevictable(page)) { + if (PageMlocked(page)) + page->mlock_count++; + goto out; } + + del_page_from_lru_list(page, lruvec); + ClearPageActive(page); + SetPageUnevictable(page); + page->mlock_count = !!PageMlocked(page); + add_page_to_lru_list(page, lruvec); + __count_vm_events(UNEVICTABLE_PGCULLED, thp_nr_pages(page)); +out: + SetPageLRU(page); + return lruvec; } -/* - * Isolate a page from LRU with optional get_page() pin. - * Assumes lru_lock already held and page already pinned. - */ -static bool __munlock_isolate_lru_page(struct page *page, bool getpage) +static struct lruvec *__mlock_new_page(struct page *page, struct lruvec *lruvec) { - if (PageLRU(page)) { - struct lruvec *lruvec; - - lruvec = mem_cgroup_page_lruvec(page, page_pgdat(page)); - if (getpage) - get_page(page); - ClearPageLRU(page); - del_page_from_lru_list(page, lruvec, page_lru(page)); - return true; - } + VM_BUG_ON_PAGE(PageLRU(page), page); - return false; + lruvec = folio_lruvec_relock_irq(page_folio(page), lruvec); + + /* As above, this is a little surprising, but possible */ + if (unlikely(page_evictable(page))) + goto out; + + SetPageUnevictable(page); + page->mlock_count = !!PageMlocked(page); + __count_vm_events(UNEVICTABLE_PGCULLED, thp_nr_pages(page)); +out: + add_page_to_lru_list(page, lruvec); + SetPageLRU(page); + return lruvec; } -/* - * Finish munlock after successful page isolation - * - * Page must be locked. This is a wrapper for try_to_munlock() - * and putback_lru_page() with munlock accounting. - */ -static void __munlock_isolated_page(struct page *page) +static struct lruvec *__munlock_page(struct page *page, struct lruvec *lruvec) { - /* - * Optimization: if the page was mapped just once, that's our mapping - * and we don't need to check all the other vmas. - */ - if (page_mapcount(page) > 1) - try_to_munlock(page); + int nr_pages = thp_nr_pages(page); + bool isolated = false; + + if (!TestClearPageLRU(page)) + goto munlock; + + isolated = true; + lruvec = folio_lruvec_relock_irq(page_folio(page), lruvec); - /* Did try_to_unlock() succeed or punt? */ - if (!PageMlocked(page)) - count_vm_event(UNEVICTABLE_PGMUNLOCKED); + if (PageUnevictable(page)) { + /* Then mlock_count is maintained, but might undercount */ + if (page->mlock_count) + page->mlock_count--; + if (page->mlock_count) + goto out; + } + /* else assume that was the last mlock: reclaim will fix it if not */ + +munlock: + if (TestClearPageMlocked(page)) { + __mod_zone_page_state(page_zone(page), NR_MLOCK, -nr_pages); + if (isolated || !PageUnevictable(page)) + __count_vm_events(UNEVICTABLE_PGMUNLOCKED, nr_pages); + else + __count_vm_events(UNEVICTABLE_PGSTRANDED, nr_pages); + } - putback_lru_page(page); + /* page_evictable() has to be checked *after* clearing Mlocked */ + if (isolated && PageUnevictable(page) && page_evictable(page)) { + del_page_from_lru_list(page, lruvec); + ClearPageUnevictable(page); + add_page_to_lru_list(page, lruvec); + __count_vm_events(UNEVICTABLE_PGRESCUED, nr_pages); + } +out: + if (isolated) + SetPageLRU(page); + return lruvec; } /* - * Accounting for page isolation fail during munlock - * - * Performs accounting when page isolation fails in munlock. There is nothing - * else to do because it means some other task has already removed the page - * from the LRU. putback_lru_page() will take care of removing the page from - * the unevictable list, if necessary. vmscan [page_referenced()] will move - * the page back to the unevictable list if some other vma has it mlocked. + * Flags held in the low bits of a struct page pointer on the mlock_pvec. */ -static void __munlock_isolation_failed(struct page *page) +#define LRU_PAGE 0x1 +#define NEW_PAGE 0x2 +static inline struct page *mlock_lru(struct page *page) { - if (PageUnevictable(page)) - __count_vm_event(UNEVICTABLE_PGSTRANDED); - else - __count_vm_event(UNEVICTABLE_PGMUNLOCKED); + return (struct page *)((unsigned long)page + LRU_PAGE); } -/** - * munlock_vma_page - munlock a vma page - * @page: page to be unlocked, either a normal page or THP page head - * - * returns the size of the page as a page mask (0 for normal page, - * HPAGE_PMD_NR - 1 for THP head page) - * - * called from munlock()/munmap() path with page supposedly on the LRU. - * When we munlock a page, because the vma where we found the page is being - * munlock()ed or munmap()ed, we want to check whether other vmas hold the - * page locked so that we can leave it on the unevictable lru list and not - * bother vmscan with it. However, to walk the page's rmap list in - * try_to_munlock() we must isolate the page from the LRU. If some other - * task has removed the page from the LRU, we won't be able to do that. - * So we clear the PageMlocked as we might not get another chance. If we - * can't isolate the page, we leave it for putback_lru_page() and vmscan - * [page_referenced()/try_to_unmap()] to deal with. - */ -unsigned int munlock_vma_page(struct page *page) +static inline struct page *mlock_new(struct page *page) { - int nr_pages; - pg_data_t *pgdat = page_pgdat(page); - - /* For try_to_munlock() and to serialize with page migration */ - BUG_ON(!PageLocked(page)); - - VM_BUG_ON_PAGE(PageTail(page), page); + return (struct page *)((unsigned long)page + NEW_PAGE); +} - /* - * Serialize with any parallel __split_huge_page_refcount() which - * might otherwise copy PageMlocked to part of the tail pages before - * we clear it in the head page. It also stabilizes hpage_nr_pages(). - */ - spin_lock_irq(&pgdat->lru_lock); +/* + * mlock_pagevec() is derived from pagevec_lru_move_fn(): + * perhaps that can make use of such page pointer flags in future, + * but for now just keep it for mlock. We could use three separate + * pagevecs instead, but one feels better (munlocking a full pagevec + * does not need to drain mlocking pagevecs first). + */ +static void mlock_pagevec(struct pagevec *pvec) +{ + struct lruvec *lruvec = NULL; + unsigned long mlock; + struct page *page; + int i; - if (!TestClearPageMlocked(page)) { - /* Potentially, PTE-mapped THP: do not skip the rest PTEs */ - nr_pages = 1; - goto unlock_out; + for (i = 0; i < pagevec_count(pvec); i++) { + page = pvec->pages[i]; + mlock = (unsigned long)page & (LRU_PAGE | NEW_PAGE); + page = (struct page *)((unsigned long)page - mlock); + pvec->pages[i] = page; + + if (mlock & LRU_PAGE) + lruvec = __mlock_page(page, lruvec); + else if (mlock & NEW_PAGE) + lruvec = __mlock_new_page(page, lruvec); + else + lruvec = __munlock_page(page, lruvec); } - nr_pages = hpage_nr_pages(page); - __mod_zone_page_state(page_zone(page), NR_MLOCK, -nr_pages); + if (lruvec) + unlock_page_lruvec_irq(lruvec); + release_pages(pvec->pages, pvec->nr); + pagevec_reinit(pvec); +} - if (__munlock_isolate_lru_page(page, true)) { - spin_unlock_irq(&pgdat->lru_lock); - __munlock_isolated_page(page); - goto out; - } - __munlock_isolation_failed(page); +void mlock_page_drain_local(void) +{ + struct pagevec *pvec; -unlock_out: - spin_unlock_irq(&pgdat->lru_lock); + local_lock(&mlock_pvec.lock); + pvec = this_cpu_ptr(&mlock_pvec.vec); + if (pagevec_count(pvec)) + mlock_pagevec(pvec); + local_unlock(&mlock_pvec.lock); +} -out: - return nr_pages - 1; +void mlock_page_drain_remote(int cpu) +{ + struct pagevec *pvec; + + WARN_ON_ONCE(cpu_online(cpu)); + pvec = &per_cpu(mlock_pvec.vec, cpu); + if (pagevec_count(pvec)) + mlock_pagevec(pvec); } -/* - * convert get_user_pages() return value to posix mlock() error - */ -static int __mlock_posix_error_return(long retval) +bool need_mlock_page_drain(int cpu) { - if (retval == -EFAULT) - retval = -ENOMEM; - else if (retval == -ENOMEM) - retval = -EAGAIN; - return retval; + return pagevec_count(&per_cpu(mlock_pvec.vec, cpu)); } -/* - * Prepare page for fast batched LRU putback via putback_lru_evictable_pagevec() - * - * The fast path is available only for evictable pages with single mapping. - * Then we can bypass the per-cpu pvec and get better performance. - * when mapcount > 1 we need try_to_munlock() which can fail. - * when !page_evictable(), we need the full redo logic of putback_lru_page to - * avoid leaving evictable page in unevictable list. - * - * In case of success, @page is added to @pvec and @pgrescued is incremented - * in case that the page was previously unevictable. @page is also unlocked. +/** + * mlock_folio - mlock a folio already on (or temporarily off) LRU + * @folio: folio to be mlocked. */ -static bool __putback_lru_fast_prepare(struct page *page, struct pagevec *pvec, - int *pgrescued) +void mlock_folio(struct folio *folio) { - VM_BUG_ON_PAGE(PageLRU(page), page); - VM_BUG_ON_PAGE(!PageLocked(page), page); + struct pagevec *pvec; - if (page_mapcount(page) <= 1 && page_evictable(page)) { - pagevec_add(pvec, page); - if (TestClearPageUnevictable(page)) - (*pgrescued)++; - unlock_page(page); - return true; + local_lock(&mlock_pvec.lock); + pvec = this_cpu_ptr(&mlock_pvec.vec); + + if (!folio_test_set_mlocked(folio)) { + int nr_pages = folio_nr_pages(folio); + + zone_stat_mod_folio(folio, NR_MLOCK, nr_pages); + __count_vm_events(UNEVICTABLE_PGMLOCKED, nr_pages); } - return false; + folio_get(folio); + if (!pagevec_add(pvec, mlock_lru(&folio->page)) || + folio_test_large(folio) || lru_cache_disabled()) + mlock_pagevec(pvec); + local_unlock(&mlock_pvec.lock); } -/* - * Putback multiple evictable pages to the LRU - * - * Batched putback of evictable pages that bypasses the per-cpu pvec. Some of - * the pages might have meanwhile become unevictable but that is OK. +/** + * mlock_new_page - mlock a newly allocated page not yet on LRU + * @page: page to be mlocked, either a normal page or a THP head. */ -static void __putback_lru_fast(struct pagevec *pvec, int pgrescued) +void mlock_new_page(struct page *page) { - count_vm_events(UNEVICTABLE_PGMUNLOCKED, pagevec_count(pvec)); - /* - *__pagevec_lru_add() calls release_pages() so we don't call - * put_page() explicitly - */ - __pagevec_lru_add(pvec); - count_vm_events(UNEVICTABLE_PGRESCUED, pgrescued); + struct pagevec *pvec; + int nr_pages = thp_nr_pages(page); + + local_lock(&mlock_pvec.lock); + pvec = this_cpu_ptr(&mlock_pvec.vec); + SetPageMlocked(page); + mod_zone_page_state(page_zone(page), NR_MLOCK, nr_pages); + __count_vm_events(UNEVICTABLE_PGMLOCKED, nr_pages); + + get_page(page); + if (!pagevec_add(pvec, mlock_new(page)) || + PageHead(page) || lru_cache_disabled()) + mlock_pagevec(pvec); + local_unlock(&mlock_pvec.lock); } -/* - * Munlock a batch of pages from the same zone - * - * The work is split to two main phases. First phase clears the Mlocked flag - * and attempts to isolate the pages, all under a single zone lru lock. - * The second phase finishes the munlock only for pages where isolation - * succeeded. - * - * Note that the pagevec may be modified during the process. +/** + * munlock_page - munlock a page + * @page: page to be munlocked, either a normal page or a THP head. */ -static void __munlock_pagevec(struct pagevec *pvec, struct zone *zone) +void munlock_page(struct page *page) { - int i; - int nr = pagevec_count(pvec); - int delta_munlocked = -nr; - struct pagevec pvec_putback; - int pgrescued = 0; - - pagevec_init(&pvec_putback); - - /* Phase 1: page isolation */ - spin_lock_irq(&zone->zone_pgdat->lru_lock); - for (i = 0; i < nr; i++) { - struct page *page = pvec->pages[i]; - - if (TestClearPageMlocked(page)) { - /* - * We already have pin from follow_page_mask() - * so we can spare the get_page() here. - */ - if (__munlock_isolate_lru_page(page, false)) - continue; - else - __munlock_isolation_failed(page); - } else { - delta_munlocked++; - } - - /* - * We won't be munlocking this page in the next phase - * but we still need to release the follow_page_mask() - * pin. We cannot do it under lru_lock however. If it's - * the last pin, __page_cache_release() would deadlock. - */ - pagevec_add(&pvec_putback, pvec->pages[i]); - pvec->pages[i] = NULL; - } - __mod_zone_page_state(zone, NR_MLOCK, delta_munlocked); - spin_unlock_irq(&zone->zone_pgdat->lru_lock); - - /* Now we can release pins of pages that we are not munlocking */ - pagevec_release(&pvec_putback); - - /* Phase 2: page munlock */ - for (i = 0; i < nr; i++) { - struct page *page = pvec->pages[i]; - - if (page) { - lock_page(page); - if (!__putback_lru_fast_prepare(page, &pvec_putback, - &pgrescued)) { - /* - * Slow path. We don't want to lose the last - * pin before unlock_page() - */ - get_page(page); /* for putback_lru_page() */ - __munlock_isolated_page(page); - unlock_page(page); - put_page(page); /* from follow_page_mask() */ - } - } - } + struct pagevec *pvec; + local_lock(&mlock_pvec.lock); + pvec = this_cpu_ptr(&mlock_pvec.vec); /* - * Phase 3: page putback for pages that qualified for the fast path - * This will also call put_page() to return pin from follow_page_mask() + * TestClearPageMlocked(page) must be left to __munlock_page(), + * which will check whether the page is multiply mlocked. */ - if (pagevec_count(&pvec_putback)) - __putback_lru_fast(&pvec_putback, pgrescued); + + get_page(page); + if (!pagevec_add(pvec, page) || + PageHead(page) || lru_cache_disabled()) + mlock_pagevec(pvec); + local_unlock(&mlock_pvec.lock); } -/* - * Fill up pagevec for __munlock_pagevec using pte walk - * - * The function expects that the struct page corresponding to @start address is - * a non-TPH page already pinned and in the @pvec, and that it belongs to @zone. - * - * The rest of @pvec is filled by subsequent pages within the same pmd and same - * zone, as long as the pte's are present and vm_normal_page() succeeds. These - * pages also get pinned. - * - * Returns the address of the next page that should be scanned. This equals - * @start + PAGE_SIZE when no page could be added by the pte walk. - */ -static unsigned long __munlock_pagevec_fill(struct pagevec *pvec, - struct vm_area_struct *vma, struct zone *zone, - unsigned long start, unsigned long end) +static int mlock_pte_range(pmd_t *pmd, unsigned long addr, + unsigned long end, struct mm_walk *walk) + { - pte_t *pte; + struct vm_area_struct *vma = walk->vma; spinlock_t *ptl; + pte_t *start_pte, *pte; + struct page *page; - /* - * Initialize pte walk starting at the already pinned page where we - * are sure that there is a pte, as it was pinned under the same - * mmap_sem write op. - */ - pte = get_locked_pte(vma->vm_mm, start, &ptl); - /* Make sure we do not cross the page table boundary */ - end = pgd_addr_end(start, end); - end = p4d_addr_end(start, end); - end = pud_addr_end(start, end); - end = pmd_addr_end(start, end); - - /* The page next to the pinned page is the first we will try to get */ - start += PAGE_SIZE; - while (start < end) { - struct page *page = NULL; - pte++; - if (pte_present(*pte)) - page = vm_normal_page(vma, start, *pte); - /* - * Break if page could not be obtained or the page's node+zone does not - * match - */ - if (!page || page_zone(page) != zone) - break; + ptl = pmd_trans_huge_lock(pmd, vma); + if (ptl) { + if (!pmd_present(*pmd)) + goto out; + if (is_huge_zero_pmd(*pmd)) + goto out; + page = pmd_page(*pmd); + if (vma->vm_flags & VM_LOCKED) + mlock_folio(page_folio(page)); + else + munlock_page(page); + goto out; + } - /* - * Do not use pagevec for PTE-mapped THP, - * munlock_vma_pages_range() will handle them. - */ + start_pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl); + for (pte = start_pte; addr != end; pte++, addr += PAGE_SIZE) { + if (!pte_present(*pte)) + continue; + page = vm_normal_page(vma, addr, *pte); + if (!page || is_zone_device_page(page)) + continue; if (PageTransCompound(page)) - break; - - get_page(page); - /* - * Increase the address that will be returned *before* the - * eventual break due to pvec becoming full by adding the page - */ - start += PAGE_SIZE; - if (pagevec_add(pvec, page) == 0) - break; + continue; + if (vma->vm_flags & VM_LOCKED) + mlock_folio(page_folio(page)); + else + munlock_page(page); } - pte_unmap_unlock(pte, ptl); - return start; + pte_unmap(start_pte); +out: + spin_unlock(ptl); + cond_resched(); + return 0; } /* - * munlock_vma_pages_range() - munlock all pages in the vma range.' - * @vma - vma containing range to be munlock()ed. + * mlock_vma_pages_range() - mlock any pages already in the range, + * or munlock all pages in the range. + * @vma - vma containing range to be mlock()ed or munlock()ed * @start - start address in @vma of the range - * @end - end of range in @vma. - * - * For mremap(), munmap() and exit(). - * - * Called with @vma VM_LOCKED. - * - * Returns with VM_LOCKED cleared. Callers must be prepared to - * deal with this. + * @end - end of range in @vma + * @newflags - the new set of flags for @vma. * - * We don't save and restore VM_LOCKED here because pages are - * still on lru. In unmap path, pages might be scanned by reclaim - * and re-mlocked by try_to_{munlock|unmap} before we unmap and - * free them. This will result in freeing mlocked pages. + * Called for mlock(), mlock2() and mlockall(), to set @vma VM_LOCKED; + * called for munlock() and munlockall(), to clear VM_LOCKED from @vma. */ -void munlock_vma_pages_range(struct vm_area_struct *vma, - unsigned long start, unsigned long end) +static void mlock_vma_pages_range(struct vm_area_struct *vma, + unsigned long start, unsigned long end, vm_flags_t newflags) { - vma->vm_flags &= VM_LOCKED_CLEAR_MASK; + static const struct mm_walk_ops mlock_walk_ops = { + .pmd_entry = mlock_pte_range, + }; - while (start < end) { - struct page *page; - unsigned int page_mask = 0; - unsigned long page_increm; - struct pagevec pvec; - struct zone *zone; + /* + * There is a slight chance that concurrent page migration, + * or page reclaim finding a page of this now-VM_LOCKED vma, + * will call mlock_vma_page() and raise page's mlock_count: + * double counting, leaving the page unevictable indefinitely. + * Communicate this danger to mlock_vma_page() with VM_IO, + * which is a VM_SPECIAL flag not allowed on VM_LOCKED vmas. + * mmap_lock is held in write mode here, so this weird + * combination should not be visible to other mmap_lock users; + * but WRITE_ONCE so rmap walkers must see VM_IO if VM_LOCKED. + */ + if (newflags & VM_LOCKED) + newflags |= VM_IO; + WRITE_ONCE(vma->vm_flags, newflags); - pagevec_init(&pvec); - /* - * Although FOLL_DUMP is intended for get_dump_page(), - * it just so happens that its special treatment of the - * ZERO_PAGE (returning an error instead of doing get_page) - * suits munlock very well (and if somehow an abnormal page - * has sneaked into the range, we won't oops here: great). - */ - page = follow_page(vma, start, FOLL_GET | FOLL_DUMP); - - if (page && !IS_ERR(page)) { - if (PageTransTail(page)) { - VM_BUG_ON_PAGE(PageMlocked(page), page); - put_page(page); /* follow_page_mask() */ - } else if (PageTransHuge(page)) { - lock_page(page); - /* - * Any THP page found by follow_page_mask() may - * have gotten split before reaching - * munlock_vma_page(), so we need to compute - * the page_mask here instead. - */ - page_mask = munlock_vma_page(page); - unlock_page(page); - put_page(page); /* follow_page_mask() */ - } else { - /* - * Non-huge pages are handled in batches via - * pagevec. The pin from follow_page_mask() - * prevents them from collapsing by THP. - */ - pagevec_add(&pvec, page); - zone = page_zone(page); - - /* - * Try to fill the rest of pagevec using fast - * pte walk. This will also update start to - * the next page to process. Then munlock the - * pagevec. - */ - start = __munlock_pagevec_fill(&pvec, vma, - zone, start, end); - __munlock_pagevec(&pvec, zone); - goto next; - } - } - page_increm = 1 + page_mask; - start += page_increm * PAGE_SIZE; -next: - cond_resched(); + lru_add_drain(); + walk_page_range(vma->vm_mm, start, end, &mlock_walk_ops, NULL); + lru_add_drain(); + + if (newflags & VM_IO) { + newflags &= ~VM_IO; + WRITE_ONCE(vma->vm_flags, newflags); } } @@ -523,19 +408,18 @@ static int mlock_fixup(struct vm_area_struct *vma, struct vm_area_struct **prev, pgoff_t pgoff; int nr_pages; int ret = 0; - int lock = !!(newflags & VM_LOCKED); - vm_flags_t old_flags = vma->vm_flags; + vm_flags_t oldflags = vma->vm_flags; - if (newflags == vma->vm_flags || (vma->vm_flags & VM_SPECIAL) || + if (newflags == oldflags || (oldflags & VM_SPECIAL) || is_vm_hugetlb_page(vma) || vma == get_gate_vma(current->mm) || - vma_is_dax(vma)) + vma_is_dax(vma) || vma_is_secretmem(vma)) /* don't set VM_LOCKED or VM_LOCKONFAULT and don't count */ goto out; pgoff = vma->vm_pgoff + ((start - vma->vm_start) >> PAGE_SHIFT); *prev = vma_merge(mm, *prev, start, end, newflags, vma->anon_vma, vma->vm_file, pgoff, vma_policy(vma), - vma->vm_userfaultfd_ctx); + vma->vm_userfaultfd_ctx, anon_vma_name(vma)); if (*prev) { vma = *prev; goto success; @@ -558,23 +442,24 @@ success: * Keep track of amount of locked VM. */ nr_pages = (end - start) >> PAGE_SHIFT; - if (!lock) + if (!(newflags & VM_LOCKED)) nr_pages = -nr_pages; - else if (old_flags & VM_LOCKED) + else if (oldflags & VM_LOCKED) nr_pages = 0; mm->locked_vm += nr_pages; /* - * vm_flags is protected by the mmap_sem held in write mode. + * vm_flags is protected by the mmap_lock held in write mode. * It's okay if try_to_unmap_one unmaps a page just after we * set VM_LOCKED, populate_vma_page_range will bring it back. */ - if (lock) + if ((newflags & VM_LOCKED) && (oldflags & VM_LOCKED)) { + /* No work to do, and mlocking twice would be wrong */ vma->vm_flags = newflags; - else - munlock_vma_pages_range(vma, start, end); - + } else { + mlock_vma_pages_range(vma, start, end, newflags); + } out: *prev = vma; return ret; @@ -584,8 +469,9 @@ static int apply_vma_lock_flags(unsigned long start, size_t len, vm_flags_t flags) { unsigned long nstart, end, tmp; - struct vm_area_struct * vma, * prev; + struct vm_area_struct *vma, *prev; int error; + MA_STATE(mas, ¤t->mm->mm_mt, start, start); VM_BUG_ON(offset_in_page(start)); VM_BUG_ON(len != PAGE_ALIGN(len)); @@ -594,13 +480,14 @@ static int apply_vma_lock_flags(unsigned long start, size_t len, return -EINVAL; if (end == start) return 0; - vma = find_vma(current->mm, start); - if (!vma || vma->vm_start > start) + vma = mas_walk(&mas); + if (!vma) return -ENOMEM; - prev = vma->vm_prev; if (start > vma->vm_start) prev = vma; + else + prev = mas_prev(&mas, 0); for (nstart = start ; ; ) { vm_flags_t newflags = vma->vm_flags & VM_LOCKED_CLEAR_MASK; @@ -620,7 +507,7 @@ static int apply_vma_lock_flags(unsigned long start, size_t len, if (nstart >= end) break; - vma = prev->vm_next; + vma = find_vma(prev->vm_mm, prev->vm_end); if (!vma || vma->vm_start != nstart) { error = -ENOMEM; break; @@ -641,24 +528,21 @@ static unsigned long count_mm_mlocked_page_nr(struct mm_struct *mm, { struct vm_area_struct *vma; unsigned long count = 0; + unsigned long end; + VMA_ITERATOR(vmi, mm, start); - if (mm == NULL) - mm = current->mm; - - vma = find_vma(mm, start); - if (vma == NULL) - vma = mm->mmap; + /* Don't overflow past ULONG_MAX */ + if (unlikely(ULONG_MAX - len < start)) + end = ULONG_MAX; + else + end = start + len; - for (; vma ; vma = vma->vm_next) { - if (start >= vma->vm_end) - continue; - if (start + len <= vma->vm_start) - break; + for_each_vma_range(vmi, vma, end) { if (vma->vm_flags & VM_LOCKED) { if (start > vma->vm_start) count -= (start - vma->vm_start); - if (start + len < vma->vm_end) { - count += start + len - vma->vm_start; + if (end < vma->vm_end) { + count += end - vma->vm_start; break; } count += vma->vm_end - vma->vm_start; @@ -668,6 +552,18 @@ static unsigned long count_mm_mlocked_page_nr(struct mm_struct *mm, return count >> PAGE_SHIFT; } +/* + * convert get_user_pages() return value to posix mlock() error + */ +static int __mlock_posix_error_return(long retval) +{ + if (retval == -EFAULT) + retval = -ENOMEM; + else if (retval == -ENOMEM) + retval = -EAGAIN; + return retval; +} + static __must_check int do_mlock(unsigned long start, size_t len, vm_flags_t flags) { unsigned long locked; @@ -686,7 +582,7 @@ static __must_check int do_mlock(unsigned long start, size_t len, vm_flags_t fla lock_limit >>= PAGE_SHIFT; locked = len >> PAGE_SHIFT; - if (down_write_killable(¤t->mm->mmap_sem)) + if (mmap_write_lock_killable(current->mm)) return -EINTR; locked += current->mm->locked_vm; @@ -705,7 +601,7 @@ static __must_check int do_mlock(unsigned long start, size_t len, vm_flags_t fla if ((locked <= lock_limit) || capable(CAP_IPC_LOCK)) error = apply_vma_lock_flags(start, len, flags); - up_write(¤t->mm->mmap_sem); + mmap_write_unlock(current->mm); if (error) return error; @@ -742,10 +638,10 @@ SYSCALL_DEFINE2(munlock, unsigned long, start, size_t, len) len = PAGE_ALIGN(len + (offset_in_page(start))); start &= PAGE_MASK; - if (down_write_killable(¤t->mm->mmap_sem)) + if (mmap_write_lock_killable(current->mm)) return -EINTR; ret = apply_vma_lock_flags(start, len, 0); - up_write(¤t->mm->mmap_sem); + mmap_write_unlock(current->mm); return ret; } @@ -762,7 +658,8 @@ SYSCALL_DEFINE2(munlock, unsigned long, start, size_t, len) */ static int apply_mlockall_flags(int flags) { - struct vm_area_struct * vma, * prev = NULL; + MA_STATE(mas, ¤t->mm->mm_mt, 0, 0); + struct vm_area_struct *vma, *prev = NULL; vm_flags_t to_add = 0; current->mm->def_flags &= VM_LOCKED_CLEAR_MASK; @@ -782,7 +679,7 @@ static int apply_mlockall_flags(int flags) to_add |= VM_LOCKONFAULT; } - for (vma = current->mm->mmap; vma ; vma = prev->vm_next) { + mas_for_each(&mas, vma, ULONG_MAX) { vm_flags_t newflags; newflags = vma->vm_flags & VM_LOCKED_CLEAR_MASK; @@ -790,6 +687,7 @@ static int apply_mlockall_flags(int flags) /* Ignore errors */ mlock_fixup(vma, &prev, vma->vm_start, vma->vm_end, newflags); + mas_pause(&mas); cond_resched(); } out: @@ -811,14 +709,14 @@ SYSCALL_DEFINE1(mlockall, int, flags) lock_limit = rlimit(RLIMIT_MEMLOCK); lock_limit >>= PAGE_SHIFT; - if (down_write_killable(¤t->mm->mmap_sem)) + if (mmap_write_lock_killable(current->mm)) return -EINTR; ret = -ENOMEM; if (!(flags & MCL_CURRENT) || (current->mm->total_vm <= lock_limit) || capable(CAP_IPC_LOCK)) ret = apply_mlockall_flags(flags); - up_write(¤t->mm->mmap_sem); + mmap_write_unlock(current->mm); if (!ret && (flags & MCL_CURRENT)) mm_populate(0, TASK_SIZE); @@ -829,10 +727,10 @@ SYSCALL_DEFINE0(munlockall) { int ret; - if (down_write_killable(¤t->mm->mmap_sem)) + if (mmap_write_lock_killable(current->mm)) return -EINTR; ret = apply_mlockall_flags(0); - up_write(¤t->mm->mmap_sem); + mmap_write_unlock(current->mm); return ret; } @@ -842,32 +740,38 @@ SYSCALL_DEFINE0(munlockall) */ static DEFINE_SPINLOCK(shmlock_user_lock); -int user_shm_lock(size_t size, struct user_struct *user) +int user_shm_lock(size_t size, struct ucounts *ucounts) { unsigned long lock_limit, locked; + long memlock; int allowed = 0; locked = (size + PAGE_SIZE - 1) >> PAGE_SHIFT; lock_limit = rlimit(RLIMIT_MEMLOCK); - if (lock_limit == RLIM_INFINITY) - allowed = 1; - lock_limit >>= PAGE_SHIFT; + if (lock_limit != RLIM_INFINITY) + lock_limit >>= PAGE_SHIFT; spin_lock(&shmlock_user_lock); - if (!allowed && - locked + user->locked_shm > lock_limit && !capable(CAP_IPC_LOCK)) + memlock = inc_rlimit_ucounts(ucounts, UCOUNT_RLIMIT_MEMLOCK, locked); + + if ((memlock == LONG_MAX || memlock > lock_limit) && !capable(CAP_IPC_LOCK)) { + dec_rlimit_ucounts(ucounts, UCOUNT_RLIMIT_MEMLOCK, locked); goto out; - get_uid(user); - user->locked_shm += locked; + } + if (!get_ucounts(ucounts)) { + dec_rlimit_ucounts(ucounts, UCOUNT_RLIMIT_MEMLOCK, locked); + allowed = 0; + goto out; + } allowed = 1; out: spin_unlock(&shmlock_user_lock); return allowed; } -void user_shm_unlock(size_t size, struct user_struct *user) +void user_shm_unlock(size_t size, struct ucounts *ucounts) { spin_lock(&shmlock_user_lock); - user->locked_shm -= (size + PAGE_SIZE - 1) >> PAGE_SHIFT; + dec_rlimit_ucounts(ucounts, UCOUNT_RLIMIT_MEMLOCK, (size + PAGE_SIZE - 1) >> PAGE_SHIFT); spin_unlock(&shmlock_user_lock); - free_uid(user); + put_ucounts(ucounts); } |