xtensa: replace xtensa-specific _f{data,text} by _s{data,text}

[firefly-linux-kernel-4.4.55.git] / lib / radix-tree.c

diff --git a/lib/radix-tree.c b/lib/radix-tree.c
index 86516f5588e31782676087fd49fe45fd87538c03..e7964296fd50551020872d430009e890d0e97b5d 100644 (file)
--- a/lib/radix-tree.c
+++ b/lib/radix-tree.c
@@ -72,12 +72,25 @@ static unsigned long height_to_maxindex[RADIX_TREE_MAX_PATH + 1] __read_mostly;
  */
 static struct kmem_cache *radix_tree_node_cachep;
 
+/*
+ * The radix tree is variable-height, so an insert operation not only has
+ * to build the branch to its corresponding item, it also has to build the
+ * branch to existing items if the size has to be increased (by
+ * radix_tree_extend).
+ *
+ * The worst case is a zero height tree with just a single item at index 0,
+ * and then inserting an item at index ULONG_MAX. This requires 2 new branches
+ * of RADIX_TREE_MAX_PATH size to be created, with only the root node shared.
+ * Hence:
+ */
+#define RADIX_TREE_PRELOAD_SIZE (RADIX_TREE_MAX_PATH * 2 - 1)
+
 /*
  * Per-cpu pool of preloaded nodes
  */
 struct radix_tree_preload {
        int nr;
-       struct radix_tree_node *nodes[RADIX_TREE_MAX_PATH];
+       struct radix_tree_node *nodes[RADIX_TREE_PRELOAD_SIZE];
 };
 static DEFINE_PER_CPU(struct radix_tree_preload, radix_tree_preloads) = { 0, };
 
@@ -673,6 +686,9 @@ void **radix_tree_next_chunk(struct radix_tree_root *root,
         * during iterating; it can be zero only at the beginning.
         * And we cannot overflow iter->next_index in a single step,
         * because RADIX_TREE_MAP_SHIFT < BITS_PER_LONG.
+        *
+        * This condition also used by radix_tree_next_slot() to stop
+        * contiguous iterating, and forbid swithing to the next chunk.
         */
        index = iter->next_index;
        if (!index && iter->index)