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-rw-r--r--include/linux/swap.h7
-rw-r--r--mm/shmem.c2
-rw-r--r--mm/swap_state.c11
-rw-r--r--mm/swapfile.c19
-rw-r--r--mm/vmscan.c3
5 files changed, 33 insertions, 9 deletions
diff --git a/include/linux/swap.h b/include/linux/swap.h
index f30c06908f09..259e96c150ef 100644
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -282,8 +282,10 @@ extern void si_swapinfo(struct sysinfo *);
extern swp_entry_t get_swap_page(void);
extern swp_entry_t get_swap_page_of_type(int);
extern int swap_duplicate(swp_entry_t);
+extern int swapcache_prepare(swp_entry_t);
extern int valid_swaphandles(swp_entry_t, unsigned long *);
extern void swap_free(swp_entry_t);
+extern void swapcache_free(swp_entry_t, struct page *page);
extern int free_swap_and_cache(swp_entry_t);
extern int swap_type_of(dev_t, sector_t, struct block_device **);
extern unsigned int count_swap_pages(int, int);
@@ -352,11 +354,16 @@ static inline void show_swap_cache_info(void)
#define free_swap_and_cache(swp) is_migration_entry(swp)
#define swap_duplicate(swp) is_migration_entry(swp)
+#define swapcache_prepare(swp) is_migration_entry(swp)
static inline void swap_free(swp_entry_t swp)
{
}
+static inline void swapcache_free(swp_entry_t swp, struct page *page)
+{
+}
+
static inline struct page *swapin_readahead(swp_entry_t swp, gfp_t gfp_mask,
struct vm_area_struct *vma, unsigned long addr)
{
diff --git a/mm/shmem.c b/mm/shmem.c
index 0132fbd45a23..47ab19182287 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -1097,7 +1097,7 @@ static int shmem_writepage(struct page *page, struct writeback_control *wbc)
shmem_swp_unmap(entry);
unlock:
spin_unlock(&info->lock);
- swap_free(swap);
+ swapcache_free(swap, NULL);
redirty:
set_page_dirty(page);
if (wbc->for_reclaim)
diff --git a/mm/swap_state.c b/mm/swap_state.c
index 1416e7e9e02d..19bdf3017a9e 100644
--- a/mm/swap_state.c
+++ b/mm/swap_state.c
@@ -162,11 +162,11 @@ int add_to_swap(struct page *page)
return 1;
case -EEXIST:
/* Raced with "speculative" read_swap_cache_async */
- swap_free(entry);
+ swapcache_free(entry, NULL);
continue;
default:
/* -ENOMEM radix-tree allocation failure */
- swap_free(entry);
+ swapcache_free(entry, NULL);
return 0;
}
}
@@ -188,8 +188,7 @@ void delete_from_swap_cache(struct page *page)
__delete_from_swap_cache(page);
spin_unlock_irq(&swapper_space.tree_lock);
- mem_cgroup_uncharge_swapcache(page, entry);
- swap_free(entry);
+ swapcache_free(entry, page);
page_cache_release(page);
}
@@ -293,7 +292,7 @@ struct page *read_swap_cache_async(swp_entry_t entry, gfp_t gfp_mask,
/*
* Swap entry may have been freed since our caller observed it.
*/
- if (!swap_duplicate(entry))
+ if (!swapcache_prepare(entry))
break;
/*
@@ -317,7 +316,7 @@ struct page *read_swap_cache_async(swp_entry_t entry, gfp_t gfp_mask,
}
ClearPageSwapBacked(new_page);
__clear_page_locked(new_page);
- swap_free(entry);
+ swapcache_free(entry, NULL);
} while (err != -ENOMEM);
if (new_page)
diff --git a/mm/swapfile.c b/mm/swapfile.c
index 312fafe0ab6e..3187079903fd 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -510,6 +510,16 @@ void swap_free(swp_entry_t entry)
}
/*
+ * Called after dropping swapcache to decrease refcnt to swap entries.
+ */
+void swapcache_free(swp_entry_t entry, struct page *page)
+{
+ if (page)
+ mem_cgroup_uncharge_swapcache(page, entry);
+ return swap_free(entry);
+}
+
+/*
* How many references to page are currently swapped out?
*/
static inline int page_swapcount(struct page *page)
@@ -1979,6 +1989,15 @@ bad_file:
goto out;
}
+/*
+ * Called when allocating swap cache for exising swap entry,
+ */
+int swapcache_prepare(swp_entry_t entry)
+{
+ return swap_duplicate(entry);
+}
+
+
struct swap_info_struct *
get_swap_info_struct(unsigned type)
{
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 2c4b945b011f..52339dd7bf85 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -470,8 +470,7 @@ static int __remove_mapping(struct address_space *mapping, struct page *page)
swp_entry_t swap = { .val = page_private(page) };
__delete_from_swap_cache(page);
spin_unlock_irq(&mapping->tree_lock);
- mem_cgroup_uncharge_swapcache(page, swap);
- swap_free(swap);
+ swapcache_free(swap, page);
} else {
__remove_from_page_cache(page);
spin_unlock_irq(&mapping->tree_lock);