radix-tree: add radix_tree_prev_hole()

[safe/jmp/linux-2.6] / include / linux / radix-tree.h

diff --git a/include/linux/radix-tree.h b/include/linux/radix-tree.h
index b6116b4..c5da749 100644 (file)
--- a/include/linux/radix-tree.h
+++ b/include/linux/radix-tree.h
@@ -91,7 +91,7 @@ do {                                                                  \
  *
  * For API usage, in general,
  * - any function _modifying_ the tree or tags (inserting or deleting
- *   items, setting or clearing tags must exclude other modifications, and
+ *   items, setting or clearing tags) must exclude other modifications, and
  *   exclude any functions reading the tree.
  * - any function _reading_ the tree or tags (looking up items or tags,
  *   gang lookups) must exclude modifications to the tree, but may occur
@@ -99,12 +99,15 @@ do {                                                                        \
  *
  * The notable exceptions to this rule are the following functions:
  * radix_tree_lookup
+ * radix_tree_lookup_slot
  * radix_tree_tag_get
  * radix_tree_gang_lookup
+ * radix_tree_gang_lookup_slot
  * radix_tree_gang_lookup_tag
+ * radix_tree_gang_lookup_tag_slot
  * radix_tree_tagged
  *
- * The first 4 functions are able to be called locklessly, using RCU. The
+ * The first 7 functions are able to be called locklessly, using RCU. The
  * caller must ensure calls to these functions are made within rcu_read_lock()
  * regions. Other readers (lock-free or otherwise) and modifications may be
  * running concurrently.
@@ -133,7 +136,7 @@ do {                                                                        \
  */
 static inline void *radix_tree_deref_slot(void **pslot)
 {
-       void *ret = *pslot;
+       void *ret = rcu_dereference(*pslot);
        if (unlikely(radix_tree_is_indirect_ptr(ret)))
                ret = RADIX_TREE_RETRY;
        return ret;
@@ -159,8 +162,13 @@ void *radix_tree_delete(struct radix_tree_root *, unsigned long);
 unsigned int
 radix_tree_gang_lookup(struct radix_tree_root *root, void **results,
                        unsigned long first_index, unsigned int max_items);
+unsigned int
+radix_tree_gang_lookup_slot(struct radix_tree_root *root, void ***results,
+                       unsigned long first_index, unsigned int max_items);
 unsigned long radix_tree_next_hole(struct radix_tree_root *root,
                                unsigned long index, unsigned long max_scan);
+unsigned long radix_tree_prev_hole(struct radix_tree_root *root,
+                               unsigned long index, unsigned long max_scan);
 int radix_tree_preload(gfp_t gfp_mask);
 void radix_tree_init(void);
 void *radix_tree_tag_set(struct radix_tree_root *root,
@@ -173,6 +181,10 @@ unsigned int
 radix_tree_gang_lookup_tag(struct radix_tree_root *root, void **results,
                unsigned long first_index, unsigned int max_items,
                unsigned int tag);
+unsigned int
+radix_tree_gang_lookup_tag_slot(struct radix_tree_root *root, void ***results,
+               unsigned long first_index, unsigned int max_items,
+               unsigned int tag);
 int radix_tree_tagged(struct radix_tree_root *root, unsigned int tag);
 
 static inline void radix_tree_preload_end(void)