radix_tree: clean away saw_unset_tag leftovers (3fa36acb) · Commits · 戴 / test

radix_tree_tag_get()'s BUG (when it sees a tag after saw_unset_tag) was unsafe and removed in 2.6.34, but the pointless saw_unset_tag left behind. Remove it now, and return 0 as soon as we see unset tag - we already rely upon the root tag to be correct, returning 0 immediately if it's not set. Signed-off-by:

Hugh Dickins <hughd@google.com> Signed-off-by:

Andrew Morton <akpm@linux-foundation.org> Signed-off-by:

Linus Torvalds <torvalds@linux-foundation.org>

lib/radix-tree.c

+2 −8

Original line number	Diff line number	Diff line
		@@ -576,7 +576,6 @@ int radix_tree_tag_get(struct radix_tree_root *root,
		{
		unsigned int height, shift;
		struct radix_tree_node *node;
		int saw_unset_tag = 0;

		/* check the root's tag bit */
		if (!root_tag_get(root, tag))
		@@ -603,15 +602,10 @@ int radix_tree_tag_get(struct radix_tree_root *root,
		return 0;

		offset = (index >> shift) & RADIX_TREE_MAP_MASK;

		/*
		* This is just a debug check. Later, we can bale as soon as
		* we see an unset tag.
		*/
		if (!tag_get(node, tag, offset))
		saw_unset_tag = 1;
		return 0;
		if (height == 1)
		return !!tag_get(node, tag, offset);
		return 1;
		node = rcu_dereference_raw(node->slots[offset]);
		shift -= RADIX_TREE_MAP_SHIFT;
		height--;

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