diff options
Diffstat (limited to 'mm')
-rw-r--r-- | mm/filemap.c | 13 | ||||
-rw-r--r-- | mm/swapfile.c | 2 |
2 files changed, 6 insertions, 9 deletions
diff --git a/mm/filemap.c b/mm/filemap.c index a1ddd2557af2..e1b23fda48de 100644 --- a/mm/filemap.c +++ b/mm/filemap.c | |||
@@ -573,17 +573,14 @@ EXPORT_SYMBOL(wait_on_page_bit); | |||
573 | * mechananism between PageLocked pages and PageWriteback pages is shared. | 573 | * mechananism between PageLocked pages and PageWriteback pages is shared. |
574 | * But that's OK - sleepers in wait_on_page_writeback() just go back to sleep. | 574 | * But that's OK - sleepers in wait_on_page_writeback() just go back to sleep. |
575 | * | 575 | * |
576 | * The first mb is necessary to safely close the critical section opened by the | 576 | * The mb is necessary to enforce ordering between the clear_bit and the read |
577 | * test_and_set_bit() to lock the page; the second mb is necessary to enforce | 577 | * of the waitqueue (to avoid SMP races with a parallel wait_on_page_locked()). |
578 | * ordering between the clear_bit and the read of the waitqueue (to avoid SMP | ||
579 | * races with a parallel wait_on_page_locked()). | ||
580 | */ | 578 | */ |
581 | void unlock_page(struct page *page) | 579 | void unlock_page(struct page *page) |
582 | { | 580 | { |
583 | smp_mb__before_clear_bit(); | 581 | VM_BUG_ON(!PageLocked(page)); |
584 | if (!test_and_clear_bit(PG_locked, &page->flags)) | 582 | clear_bit_unlock(PG_locked, &page->flags); |
585 | BUG(); | 583 | smp_mb__after_clear_bit(); |
586 | smp_mb__after_clear_bit(); | ||
587 | wake_up_page(page, PG_locked); | 584 | wake_up_page(page, PG_locked); |
588 | } | 585 | } |
589 | EXPORT_SYMBOL(unlock_page); | 586 | EXPORT_SYMBOL(unlock_page); |
diff --git a/mm/swapfile.c b/mm/swapfile.c index 2a97fafa3d89..90cb67a5417c 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c | |||
@@ -422,7 +422,7 @@ void free_swap_and_cache(swp_entry_t entry) | |||
422 | if (p) { | 422 | if (p) { |
423 | if (swap_entry_free(p, swp_offset(entry)) == 1) { | 423 | if (swap_entry_free(p, swp_offset(entry)) == 1) { |
424 | page = find_get_page(&swapper_space, entry.val); | 424 | page = find_get_page(&swapper_space, entry.val); |
425 | if (page && unlikely(!trylock_page(page))) { | 425 | if (page && !trylock_page(page)) { |
426 | page_cache_release(page); | 426 | page_cache_release(page); |
427 | page = NULL; | 427 | page = NULL; |
428 | } | 428 | } |