diff options
| -rw-r--r-- | include/linux/swap.h | 4 | ||||
| -rw-r--r-- | mm/swapfile.c | 23 |
2 files changed, 21 insertions, 6 deletions
diff --git a/include/linux/swap.h b/include/linux/swap.h index b489bd77bbdc..f02fb5db8914 100644 --- a/include/linux/swap.h +++ b/include/linux/swap.h @@ -266,6 +266,10 @@ struct swap_info_struct { * both locks need hold, hold swap_lock * first. */ + spinlock_t cont_lock; /* + * protect swap count continuation page + * list. + */ struct work_struct discard_work; /* discard worker */ struct swap_cluster_list discard_clusters; /* discard clusters list */ }; diff --git a/mm/swapfile.c b/mm/swapfile.c index bf91dc9e7a79..e47a21e64764 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -2869,6 +2869,7 @@ static struct swap_info_struct *alloc_swap_info(void) p->flags = SWP_USED; spin_unlock(&swap_lock); spin_lock_init(&p->lock); + spin_lock_init(&p->cont_lock); return p; } @@ -3545,6 +3546,7 @@ int add_swap_count_continuation(swp_entry_t entry, gfp_t gfp_mask) head = vmalloc_to_page(si->swap_map + offset); offset &= ~PAGE_MASK; + spin_lock(&si->cont_lock); /* * Page allocation does not initialize the page's lru field, * but it does always reset its private field. @@ -3564,7 +3566,7 @@ int add_swap_count_continuation(swp_entry_t entry, gfp_t gfp_mask) * a continuation page, free our allocation and use this one. */ if (!(count & COUNT_CONTINUED)) - goto out; + goto out_unlock_cont; map = kmap_atomic(list_page) + offset; count = *map; @@ -3575,11 +3577,13 @@ int add_swap_count_continuation(swp_entry_t entry, gfp_t gfp_mask) * free our allocation and use this one. */ if ((count & ~COUNT_CONTINUED) != SWAP_CONT_MAX) - goto out; + goto out_unlock_cont; } list_add_tail(&page->lru, &head->lru); page = NULL; /* now it's attached, don't free it */ +out_unlock_cont: + spin_unlock(&si->cont_lock); out: unlock_cluster(ci); spin_unlock(&si->lock); @@ -3604,6 +3608,7 @@ static bool swap_count_continued(struct swap_info_struct *si, struct page *head; struct page *page; unsigned char *map; + bool ret; head = vmalloc_to_page(si->swap_map + offset); if (page_private(head) != SWP_CONTINUED) { @@ -3611,6 +3616,7 @@ static bool swap_count_continued(struct swap_info_struct *si, return false; /* need to add count continuation */ } + spin_lock(&si->cont_lock); offset &= ~PAGE_MASK; page = list_entry(head->lru.next, struct page, lru); map = kmap_atomic(page) + offset; @@ -3631,8 +3637,10 @@ static bool swap_count_continued(struct swap_info_struct *si, if (*map == SWAP_CONT_MAX) { kunmap_atomic(map); page = list_entry(page->lru.next, struct page, lru); - if (page == head) - return false; /* add count continuation */ + if (page == head) { + ret = false; /* add count continuation */ + goto out; + } map = kmap_atomic(page) + offset; init_map: *map = 0; /* we didn't zero the page */ } @@ -3645,7 +3653,7 @@ init_map: *map = 0; /* we didn't zero the page */ kunmap_atomic(map); page = list_entry(page->lru.prev, struct page, lru); } - return true; /* incremented */ + ret = true; /* incremented */ } else { /* decrementing */ /* @@ -3671,8 +3679,11 @@ init_map: *map = 0; /* we didn't zero the page */ kunmap_atomic(map); page = list_entry(page->lru.prev, struct page, lru); } - return count == COUNT_CONTINUED; + ret = count == COUNT_CONTINUED; } +out: + spin_unlock(&si->cont_lock); + return ret; } /* |