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radix-tree: rewrite radix_tree_tag_get 

Use the new multi-order support functions to rewrite
radix_tree_tag_get()

Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Kirill Shutemov <kirill.shutemov@linux.intel.com>
Cc: Jan Kara <jack@suse.com>
Cc: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Ross Zwisler 2016-05-20 17:02:38 -07:00 committed by Linus Torvalds
parent 00f47b5811
commit 4589ba6d0f
1 changed files with 20 additions and 28 deletions
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48
lib/radix-tree.c
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@ -831,45 +831,37 @@ EXPORT_SYMBOL(radix_tree_tag_clear);
int radix_tree_tag_get(struct radix_tree_root *root,
unsigned long index, unsigned int tag)
{
unsigned int height, shift;
struct radix_tree_node *node;
struct radix_tree_node *node, *parent;
unsigned long maxindex;
unsigned int shift;
/* check the root's tag bit */
if (!root_tag_get(root, tag))
return 0;
node = rcu_dereference_raw(root->rnode);
shift = radix_tree_load_root(root, &node, &maxindex);
if (index > maxindex)
return 0;
if (node == NULL)
return 0;
if (!radix_tree_is_indirect_ptr(node))
return (index == 0);
node = indirect_to_ptr(node);
height = node->path & RADIX_TREE_HEIGHT_MASK;
if (index > radix_tree_maxindex(height))
return 0;
shift = (height - 1) * RADIX_TREE_MAP_SHIFT;
for ( ; ; ) {
while (radix_tree_is_indirect_ptr(node)) {
int offset;
if (node == NULL)
return 0;
node = indirect_to_ptr(node);
offset = (index >> shift) & RADIX_TREE_MAP_MASK;
if (!tag_get(node, tag, offset))
return 0;
if (height == 1)
return 1;
node = rcu_dereference_raw(node->slots[offset]);
if (!radix_tree_is_indirect_ptr(node))
return 1;
shift -= RADIX_TREE_MAP_SHIFT;
height--;
offset = (index >> shift) & RADIX_TREE_MAP_MASK;
parent = indirect_to_ptr(node);
offset = radix_tree_descend(parent, &node, offset);
if (!node)
return 0;
if (!tag_get(parent, tag, offset))
return 0;
if (node == RADIX_TREE_RETRY)
break;
}
return 1;
}
EXPORT_SYMBOL(radix_tree_tag_get);