From daff89f324755f87a060d5125a205c0755811ea9 Mon Sep 17 00:00:00 2001 From: Jonathan Corbet Date: Sat, 25 Mar 2006 03:08:05 -0800 Subject: [PATCH] radix-tree documentation cleanups Documentation changes to help radix tree users avoid overrunning the tags array. RADIX_TREE_TAGS moves to linux/radix-tree.h and is now known as RADIX_TREE_MAX_TAGS (Nick Piggin's idea). Tag parameters are changed to unsigned, and some comments are updated. Signed-off-by: Jonathan Corbet Cc: Nick Piggin Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- lib/radix-tree.c | 49 +++++++++++++++++++++++++++---------------------- 1 file changed, 27 insertions(+), 22 deletions(-) (limited to 'lib') diff --git a/lib/radix-tree.c b/lib/radix-tree.c index 1e5b17dc7e3d..7097bb239e40 100644 --- a/lib/radix-tree.c +++ b/lib/radix-tree.c @@ -37,7 +37,6 @@ #else #define RADIX_TREE_MAP_SHIFT 3 /* For more stressful testing */ #endif -#define RADIX_TREE_TAGS 2 #define RADIX_TREE_MAP_SIZE (1UL << RADIX_TREE_MAP_SHIFT) #define RADIX_TREE_MAP_MASK (RADIX_TREE_MAP_SIZE-1) @@ -48,7 +47,7 @@ struct radix_tree_node { unsigned int count; void *slots[RADIX_TREE_MAP_SIZE]; - unsigned long tags[RADIX_TREE_TAGS][RADIX_TREE_TAG_LONGS]; + unsigned long tags[RADIX_TREE_MAX_TAGS][RADIX_TREE_TAG_LONGS]; }; struct radix_tree_path { @@ -135,17 +134,20 @@ out: return ret; } -static inline void tag_set(struct radix_tree_node *node, int tag, int offset) +static inline void tag_set(struct radix_tree_node *node, unsigned int tag, + int offset) { __set_bit(offset, node->tags[tag]); } -static inline void tag_clear(struct radix_tree_node *node, int tag, int offset) +static inline void tag_clear(struct radix_tree_node *node, unsigned int tag, + int offset) { __clear_bit(offset, node->tags[tag]); } -static inline int tag_get(struct radix_tree_node *node, int tag, int offset) +static inline int tag_get(struct radix_tree_node *node, unsigned int tag, + int offset) { return test_bit(offset, node->tags[tag]); } @@ -154,7 +156,7 @@ static inline int tag_get(struct radix_tree_node *node, int tag, int offset) * Returns 1 if any slot in the node has this tag set. * Otherwise returns 0. */ -static inline int any_tag_set(struct radix_tree_node *node, int tag) +static inline int any_tag_set(struct radix_tree_node *node, unsigned int tag) { int idx; for (idx = 0; idx < RADIX_TREE_TAG_LONGS; idx++) { @@ -180,7 +182,7 @@ static int radix_tree_extend(struct radix_tree_root *root, unsigned long index) { struct radix_tree_node *node; unsigned int height; - char tags[RADIX_TREE_TAGS]; + char tags[RADIX_TREE_MAX_TAGS]; int tag; /* Figure out what the height should be. */ @@ -197,7 +199,7 @@ static int radix_tree_extend(struct radix_tree_root *root, unsigned long index) * Prepare the tag status of the top-level node for propagation * into the newly-pushed top-level node(s) */ - for (tag = 0; tag < RADIX_TREE_TAGS; tag++) { + for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) { tags[tag] = 0; if (any_tag_set(root->rnode, tag)) tags[tag] = 1; @@ -211,7 +213,7 @@ static int radix_tree_extend(struct radix_tree_root *root, unsigned long index) node->slots[0] = root->rnode; /* Propagate the aggregated tag info into the new root */ - for (tag = 0; tag < RADIX_TREE_TAGS; tag++) { + for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) { if (tags[tag]) tag_set(node, tag, 0); } @@ -349,14 +351,15 @@ EXPORT_SYMBOL(radix_tree_lookup); * @index: index key * @tag: tag index * - * Set the search tag corresponging to @index in the radix tree. From + * Set the search tag (which must be < RADIX_TREE_MAX_TAGS) + * corresponding to @index in the radix tree. From * the root all the way down to the leaf node. * * Returns the address of the tagged item. Setting a tag on a not-present * item is a bug. */ void *radix_tree_tag_set(struct radix_tree_root *root, - unsigned long index, int tag) + unsigned long index, unsigned int tag) { unsigned int height, shift; struct radix_tree_node *slot; @@ -390,7 +393,8 @@ EXPORT_SYMBOL(radix_tree_tag_set); * @index: index key * @tag: tag index * - * Clear the search tag corresponging to @index in the radix tree. If + * Clear the search tag (which must be < RADIX_TREE_MAX_TAGS) + * corresponding to @index in the radix tree. If * this causes the leaf node to have no tags set then clear the tag in the * next-to-leaf node, etc. * @@ -398,7 +402,7 @@ EXPORT_SYMBOL(radix_tree_tag_set); * has the same return value and semantics as radix_tree_lookup(). */ void *radix_tree_tag_clear(struct radix_tree_root *root, - unsigned long index, int tag) + unsigned long index, unsigned int tag) { struct radix_tree_path path[RADIX_TREE_MAX_PATH], *pathp = path; struct radix_tree_node *slot; @@ -450,7 +454,7 @@ EXPORT_SYMBOL(radix_tree_tag_clear); * radix_tree_tag_get - get a tag on a radix tree node * @root: radix tree root * @index: index key - * @tag: tag index + * @tag: tag index (< RADIX_TREE_MAX_TAGS) * * Return values: * @@ -459,7 +463,7 @@ EXPORT_SYMBOL(radix_tree_tag_clear); * -1: tag present, unset */ int radix_tree_tag_get(struct radix_tree_root *root, - unsigned long index, int tag) + unsigned long index, unsigned int tag) { unsigned int height, shift; struct radix_tree_node *slot; @@ -592,7 +596,7 @@ EXPORT_SYMBOL(radix_tree_gang_lookup); */ static unsigned int __lookup_tag(struct radix_tree_root *root, void **results, unsigned long index, - unsigned int max_items, unsigned long *next_index, int tag) + unsigned int max_items, unsigned long *next_index, unsigned int tag) { unsigned int nr_found = 0; unsigned int shift; @@ -646,7 +650,7 @@ out: * @results: where the results of the lookup are placed * @first_index: start the lookup from this key * @max_items: place up to this many items at *results - * @tag: the tag index + * @tag: the tag index (< RADIX_TREE_MAX_TAGS) * * Performs an index-ascending scan of the tree for present items which * have the tag indexed by @tag set. Places the items at *@results and @@ -654,7 +658,8 @@ out: */ unsigned int radix_tree_gang_lookup_tag(struct radix_tree_root *root, void **results, - unsigned long first_index, unsigned int max_items, int tag) + unsigned long first_index, unsigned int max_items, + unsigned int tag) { const unsigned long max_index = radix_tree_maxindex(root->height); unsigned long cur_index = first_index; @@ -716,7 +721,7 @@ void *radix_tree_delete(struct radix_tree_root *root, unsigned long index) struct radix_tree_node *slot; unsigned int height, shift; void *ret = NULL; - char tags[RADIX_TREE_TAGS]; + char tags[RADIX_TREE_MAX_TAGS]; int nr_cleared_tags; int tag; int offset; @@ -751,7 +756,7 @@ void *radix_tree_delete(struct radix_tree_root *root, unsigned long index) * Clear all tags associated with the just-deleted item */ nr_cleared_tags = 0; - for (tag = 0; tag < RADIX_TREE_TAGS; tag++) { + for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) { tags[tag] = 1; if (tag_get(pathp->node, tag, pathp->offset)) { tag_clear(pathp->node, tag, pathp->offset); @@ -763,7 +768,7 @@ void *radix_tree_delete(struct radix_tree_root *root, unsigned long index) } for (pathp--; nr_cleared_tags && pathp->node; pathp--) { - for (tag = 0; tag < RADIX_TREE_TAGS; tag++) { + for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) { if (tags[tag]) continue; @@ -801,7 +806,7 @@ EXPORT_SYMBOL(radix_tree_delete); * @root: radix tree root * @tag: tag to test */ -int radix_tree_tagged(struct radix_tree_root *root, int tag) +int radix_tree_tagged(struct radix_tree_root *root, unsigned int tag) { struct radix_tree_node *rnode; rnode = root->rnode; -- cgit v1.2.3