[PATCH 23/30] radix-tree: Rewrite radix_tree_tag_clear

Matthew Wilcox
2016-04-06T21:25:58Z

From: Ross Zwisler <ross.zwisler@linux.intel.com>

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

Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
---
lib/radix-tree.c | 44 ++++++++++++++++++++------------------------
1 file changed, 20 insertions(+), 24 deletions(-)

diff --git a/lib/radix-tree.c b/lib/radix-tree.c
index 6d9b328705a1..aca7b2814d26 100644
--- a/lib/radix-tree.c
+++ b/lib/radix-tree.c
@@ -775,44 +775,40 @@ EXPORT_SYMBOL(radix_tree_tag_set);
void *radix_tree_tag_clear(struct radix_tree_root *root,
unsigned long index, unsigned int tag)
{
- struct radix_tree_node *node = NULL;
- struct radix_tree_node *slot = NULL;
- unsigned int height, shift;
+ struct radix_tree_node *node, *parent;
+ unsigned long maxindex;
+ unsigned int shift;
int uninitialized_var(offset);

- height = root->height;
- if (index > radix_tree_maxindex(height))
- goto out;
-
- shift = height * RADIX_TREE_MAP_SHIFT;
- slot = root->rnode;
+ shift = radix_tree_load_root(root, &node, &maxindex);
+ if (index > maxindex)
+ return NULL;

- while (shift) {
- if (slot == NULL)
- goto out;
- if (!radix_tree_is_indirect_ptr(slot))
- break;
- slot = indirect_to_ptr(slot);
+ parent = NULL;

+ while (radix_tree_is_indirect_ptr(node)) {
shift -= RADIX_TREE_MAP_SHIFT;
offset = (index >> shift) & RADIX_TREE_MAP_MASK;
- node = slot;
- slot = slot->slots[offset];
+
+ parent = indirect_to_ptr(node);
+ offset = radix_tree_descend(parent, &node, offset);
}

- if (slot == NULL)
+ if (node == NULL)
goto out;

- while (node) {
- if (!tag_get(node, tag, offset))
+ index >>= shift;
+
+ while (parent) {
+ if (!tag_get(parent, tag, offset))
goto out;
- tag_clear(node, tag, offset);
- if (any_tag_set(node, tag))
+ tag_clear(parent, tag, offset);
+ if (any_tag_set(parent, tag))
goto out;

index >>= RADIX_TREE_MAP_SHIFT;
offset = index & RADIX_TREE_MAP_MASK;
- node = node->parent;
+ parent = parent->parent;
}

/* clear the root's tag bit */
@@ -820,7 +816,7 @@ void *radix_tree_tag_clear(struct radix_tree_root *root,
root_tag_clear(root, tag);

out:
- return slot;
+ return node;
}
EXPORT_SYMBOL(radix_tree_tag_clear);

--
2.8.0.rc3