Commit 72c47832 authored Jul 25, 2011 by Konstantin Khlebnikov Committed by Linus Torvalds Jul 25, 2011

mm: remove useless rcu lock-unlock from mapping_tagged()



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@openvz.org>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 76d3fbf8

mm/page-writeback.c

+1 −5

Original line number	Diff line number	Diff line
		@@ -1405,10 +1405,6 @@ 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);