The patch titled
mm: remove useless rcu lock-unlock from mapping_tagged()
has been added to the -mm tree. Its filename is
mm-remove-useless-rcu-lock-unlock-from-mapping_tagged.patch
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Subject: mm: remove useless rcu lock-unlock from mapping_tagged()
From: Konstantin Khlebnikov <khlebnikov@xxxxxxxxxx>
radix_tree_tagged() is lockless - it reads from a member of the raid-tree
root node. It does not require any protection.
Signed-off-by: Konstantin Khlebnikov <khlebnikov@xxxxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/page-writeback.c | 6 +-----
1 file changed, 1 insertion(+), 5 deletions(-)
diff -puN mm/page-writeback.c~mm-remove-useless-rcu-lock-unlock-from-mapping_tagged mm/page-writeback.c
--- a/mm/page-writeback.c~mm-remove-useless-rcu-lock-unlock-from-mapping_tagged
+++ a/mm/page-writeback.c
@@ -1611,10 +1611,6 @@ EXPORT_SYMBOL(test_set_page_writeback);
*/
int mapping_tagged(struct address_space *mapping, int tag)
{
- int ret;
- rcu_read_lock();
- ret = radix_tree_tagged(&mapping->page_tree, tag);
- rcu_read_unlock();
- return ret;
+ return radix_tree_tagged(&mapping->page_tree, tag);
}
EXPORT_SYMBOL(mapping_tagged);
_
Patches currently in -mm which might be from khlebnikov@xxxxxxxxxx are
mm-remove-useless-rcu-lock-unlock-from-mapping_tagged.patch
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