X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=lib%2Fradix-tree.c;h=bd521716ab1a0498242e5dabc7021f1db7e0d91a;hb=faa6cfde747ba6d37a0889cbe85881c80806d355;hp=0eee4020a7be750a6d601c039ab2bca2a6c71111;hpb=c0bc9875b701c588e448302d41181995c21e8040;p=linux-2.6

diff --git a/lib/radix-tree.c b/lib/radix-tree.c
index 0eee4020a7..bd521716ab 100644
--- a/lib/radix-tree.c
+++ b/lib/radix-tree.c
@@ -60,9 +60,14 @@ struct radix_tree_path {
 };
 
 #define RADIX_TREE_INDEX_BITS  (8 /* CHAR_BIT */ * sizeof(unsigned long))
-#define RADIX_TREE_MAX_PATH (RADIX_TREE_INDEX_BITS/RADIX_TREE_MAP_SHIFT + 2)
+#define RADIX_TREE_MAX_PATH (DIV_ROUND_UP(RADIX_TREE_INDEX_BITS, \
+					  RADIX_TREE_MAP_SHIFT))
 
-static unsigned long height_to_maxindex[RADIX_TREE_MAX_PATH] __read_mostly;
+/*
+ * The height_to_maxindex array needs to be one deeper than the maximum
+ * path as height 0 holds only 1 entry.
+ */
+static unsigned long height_to_maxindex[RADIX_TREE_MAX_PATH + 1] __read_mostly;
 
 /*
  * Radix tree node cache.
@@ -90,13 +95,17 @@ static inline gfp_t root_gfp_mask(struct radix_tree_root *root)
 static struct radix_tree_node *
 radix_tree_node_alloc(struct radix_tree_root *root)
 {
-	struct radix_tree_node *ret;
+	struct radix_tree_node *ret = NULL;
 	gfp_t gfp_mask = root_gfp_mask(root);
 
-	ret = kmem_cache_alloc(radix_tree_node_cachep, gfp_mask);
-	if (ret == NULL && !(gfp_mask & __GFP_WAIT)) {
+	if (!(gfp_mask & __GFP_WAIT)) {
 		struct radix_tree_preload *rtp;
 
+		/*
+		 * Provided the caller has preloaded here, we will always
+		 * succeed in getting a node here (and never reach
+		 * kmem_cache_alloc)
+		 */
 		rtp = &__get_cpu_var(radix_tree_preloads);
 		if (rtp->nr) {
 			ret = rtp->nodes[rtp->nr - 1];
@@ -104,6 +113,9 @@ radix_tree_node_alloc(struct radix_tree_root *root)
 			rtp->nr--;
 		}
 	}
+	if (ret == NULL)
+		ret = kmem_cache_alloc(radix_tree_node_cachep, gfp_mask);
+
 	BUG_ON(radix_tree_is_indirect_ptr(ret));
 	return ret;
 }
@@ -492,7 +504,11 @@ 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_path path[RADIX_TREE_MAX_PATH], *pathp = path;
+	/*
+	 * The radix tree path needs to be one longer than the maximum path
+	 * since the "list" is null terminated.
+	 */
+	struct radix_tree_path path[RADIX_TREE_MAX_PATH + 1], *pathp = path;
 	struct radix_tree_node *slot = NULL;
 	unsigned int height, shift;
 
@@ -934,7 +950,11 @@ static inline void radix_tree_shrink(struct radix_tree_root *root)
  */
 void *radix_tree_delete(struct radix_tree_root *root, unsigned long index)
 {
-	struct radix_tree_path path[RADIX_TREE_MAX_PATH], *pathp = path;
+	/*
+	 * The radix tree path needs to be one longer than the maximum path
+	 * since the "list" is null terminated.
+	 */
+	struct radix_tree_path path[RADIX_TREE_MAX_PATH + 1], *pathp = path;
 	struct radix_tree_node *slot = NULL;
 	struct radix_tree_node *to_free;
 	unsigned int height, shift;
@@ -1027,19 +1047,21 @@ int radix_tree_tagged(struct radix_tree_root *root, unsigned int tag)
 EXPORT_SYMBOL(radix_tree_tagged);
 
 static void
-radix_tree_node_ctor(void *node, struct kmem_cache *cachep, unsigned long flags)
+radix_tree_node_ctor(struct kmem_cache *cachep, void *node)
 {
 	memset(node, 0, sizeof(struct radix_tree_node));
 }
 
 static __init unsigned long __maxindex(unsigned int height)
 {
-	unsigned int tmp = height * RADIX_TREE_MAP_SHIFT;
-	unsigned long index = (~0UL >> (RADIX_TREE_INDEX_BITS - tmp - 1)) >> 1;
-
-	if (tmp >= RADIX_TREE_INDEX_BITS)
-		index = ~0UL;
-	return index;
+	unsigned int width = height * RADIX_TREE_MAP_SHIFT;
+	int shift = RADIX_TREE_INDEX_BITS - width;
+
+	if (shift < 0)
+		return ~0UL;
+	if (shift >= BITS_PER_LONG)
+		return 0UL;
+	return ~0UL >> shift;
 }
 
 static __init void radix_tree_init_maxindex(void)
@@ -1074,7 +1096,8 @@ void __init radix_tree_init(void)
 {
 	radix_tree_node_cachep = kmem_cache_create("radix_tree_node",
 			sizeof(struct radix_tree_node), 0,
-			SLAB_PANIC, radix_tree_node_ctor);
+			SLAB_PANIC | SLAB_RECLAIM_ACCOUNT,
+			radix_tree_node_ctor);
 	radix_tree_init_maxindex();
 	hotcpu_notifier(radix_tree_callback, 0);
 }