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-rw-r--r--include/linux/radix-tree.h1
-rw-r--r--lib/radix-tree.c31
2 files changed, 28 insertions, 4 deletions
diff --git a/include/linux/radix-tree.h b/include/linux/radix-tree.h
index 403940787be1..1bf0a9c388d9 100644
--- a/include/linux/radix-tree.h
+++ b/include/linux/radix-tree.h
@@ -219,6 +219,7 @@ static inline void radix_tree_replace_slot(void **pslot, void *item)
int radix_tree_insert(struct radix_tree_root *, unsigned long, void *);
void *radix_tree_lookup(struct radix_tree_root *, unsigned long);
void **radix_tree_lookup_slot(struct radix_tree_root *, unsigned long);
+void *radix_tree_delete_item(struct radix_tree_root *, unsigned long, void *);
void *radix_tree_delete(struct radix_tree_root *, unsigned long);
unsigned int
radix_tree_gang_lookup(struct radix_tree_root *root, void **results,
diff --git a/lib/radix-tree.c b/lib/radix-tree.c
index bd4a8dfdf0b8..d832117e7d94 100644
--- a/lib/radix-tree.c
+++ b/lib/radix-tree.c
@@ -1337,15 +1337,18 @@ static inline void radix_tree_shrink(struct radix_tree_root *root)
}
/**
- * radix_tree_delete - delete an item from a radix tree
+ * radix_tree_delete_item - delete an item from a radix tree
* @root: radix tree root
* @index: index key
+ * @item: expected item
*
- * Remove the item at @index from the radix tree rooted at @root.
+ * Remove @item at @index from the radix tree rooted at @root.
*
- * Returns the address of the deleted item, or NULL if it was not present.
+ * Returns the address of the deleted item, or NULL if it was not present
+ * or the entry at the given @index was not @item.
*/
-void *radix_tree_delete(struct radix_tree_root *root, unsigned long index)
+void *radix_tree_delete_item(struct radix_tree_root *root,
+ unsigned long index, void *item)
{
struct radix_tree_node *node = NULL;
struct radix_tree_node *slot = NULL;
@@ -1380,6 +1383,11 @@ void *radix_tree_delete(struct radix_tree_root *root, unsigned long index)
if (slot == NULL)
goto out;
+ if (item && slot != item) {
+ slot = NULL;
+ goto out;
+ }
+
/*
* Clear all tags associated with the item to be deleted.
* This way of doing it would be inefficient, but seldom is any set.
@@ -1424,6 +1432,21 @@ void *radix_tree_delete(struct radix_tree_root *root, unsigned long index)
out:
return slot;
}
+EXPORT_SYMBOL(radix_tree_delete_item);
+
+/**
+ * radix_tree_delete - delete an item from a radix tree
+ * @root: radix tree root
+ * @index: index key
+ *
+ * Remove the item at @index from the radix tree rooted at @root.
+ *
+ * Returns the address of the deleted item, or NULL if it was not present.
+ */
+void *radix_tree_delete(struct radix_tree_root *root, unsigned long index)
+{
+ return radix_tree_delete_item(root, index, NULL);
+}
EXPORT_SYMBOL(radix_tree_delete);
/**