radix-tree: add gang_lookup_slot, gang_lookup_slot_tag

Introduce gang_lookup_slot() and gang_lookup_slot_tag() functions, which
are used by lockless pagecache.

Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Hugh Dickins <hugh@veritas.com>
Cc: "Paul E. McKenney" <paulmck@us.ibm.com>
Reviewed-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 11 insertions, 1 deletions

diff --git a/include/linux/radix-tree.h b/include/linux/radix-tree.h
index b8ce2b444bb5..a916c6660dfa 100644
--- a/include/linux/radix-tree.h
+++ b/include/linux/radix-tree.h
@@ -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.
@@ -159,6 +162,9 @@ 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);
 int radix_tree_preload(gfp_t gfp_mask);
@@ -173,6 +179,10 @@ 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)