The patch titled
mm: clarify __add_to_swap_cache locking
has been removed from the -mm tree. Its filename was
mm-clarify-__add_to_swap_cache-locking.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
Subject: mm: clarify __add_to_swap_cache locking
From: Nick Piggin <npiggin@xxxxxxx>
__add_to_swap_cache unconditionally sets the page locked, which can be a bit
alarming to the unsuspecting reader: in the code paths where the page is
visible to other CPUs, the page should be (and is) already locked.
Instead, just add a check to ensure the page is locked here, and teach the one
path relying on the old behaviour to call SetPageLocked itself.
[hugh@xxxxxxxxxxx: locking fix]
Signed-off-by: Nick Piggin <npiggin@xxxxxxx>
Signed-off-by: Hugh Dickins <hugh@xxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/swap_state.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff -puN mm/swap_state.c~mm-clarify-__add_to_swap_cache-locking mm/swap_state.c
--- a/mm/swap_state.c~mm-clarify-__add_to_swap_cache-locking
+++ a/mm/swap_state.c
@@ -74,6 +74,7 @@ static int __add_to_swap_cache(struct pa
{
int error;
+ BUG_ON(!PageLocked(page));
BUG_ON(PageSwapCache(page));
BUG_ON(PagePrivate(page));
error = radix_tree_preload(gfp_mask);
@@ -83,7 +84,6 @@ static int __add_to_swap_cache(struct pa
entry.val, page);
if (!error) {
page_cache_get(page);
- SetPageLocked(page);
SetPageSwapCache(page);
set_page_private(page, entry.val);
total_swapcache_pages++;
@@ -99,15 +99,18 @@ static int add_to_swap_cache(struct page
{
int error;
+ BUG_ON(PageLocked(page));
if (!swap_duplicate(entry)) {
INC_CACHE_INFO(noent_race);
return -ENOENT;
}
+ SetPageLocked(page);
error = __add_to_swap_cache(page, entry, GFP_KERNEL);
/*
* Anon pages are already on the LRU, we don't run lru_cache_add here.
*/
if (error) {
+ ClearPageLocked(page);
swap_free(entry);
if (error == -EEXIST)
INC_CACHE_INFO(exist_race);
_
Patches currently in -mm which might be from npiggin@xxxxxxx are
origin.patch
mm-document-tree_lock-zonelock-lockorder.patch
fs-reiserfs-cleanups.patch
atomic_opstxt-has-incorrect-misleading-and-insufficient-information.patch
fs-introduce-write_begin-write_end-and-perform_write-aops-revoke.patch
fs-introduce-write_begin-write_end-and-perform_write-aops-revoke-fix.patch
bitops-introduce-lock-ops.patch
alpha-fix-bitops.patch
alpha-lock-bitops.patch
alpha-lock-bitops-fix.patch
ia64-lock-bitops.patch
mips-fix-bitops.patch
mips-lock-bitops.patch
powerpc-lock-bitops.patch
powerpc-lock-bitops-fix.patch
bit_spin_lock-use-lock-bitops.patch
reiser4-fix-for-new-aops-patches.patch
-
To unsubscribe from this list: send the line "unsubscribe mm-commits" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
