Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932356AbWEZLw5 (ORCPT ); Fri, 26 May 2006 07:52:57 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932364AbWEZLw5 (ORCPT ); Fri, 26 May 2006 07:52:57 -0400 Received: from smtp.ustc.edu.cn ([202.38.64.16]:60888 "HELO ustc.edu.cn") by vger.kernel.org with SMTP id S932356AbWEZLw4 (ORCPT ); Fri, 26 May 2006 07:52:56 -0400 Message-ID: <348644373.06563@ustc.edu.cn> X-EYOUMAIL-SMTPAUTH: wfg@mail.ustc.edu.cn Message-Id: <20060526115259.223408850@localhost.localdomain> References: <20060526113906.084341801@localhost.localdomain> Date: Fri, 26 May 2006 19:39:08 +0800 From: Wu Fengguang To: Andrew Morton Cc: linux-kernel@vger.kernel.org, Wu Fengguang , Nick Piggin , Christoph Lameter Subject: [PATCH 02/33] radixtree: introduce __radix_tree_lookup_parent() Content-Disposition: inline; filename=radixtree-lookup-parent.patch Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4485 Lines: 145 Introduce a general lookup function to radix tree. - __radix_tree_lookup_parent(root, index, level) Perform partial lookup, return the @level'th parent of the slot at @index. Signed-off-by: Christoph Lameter Signed-off-by: Wu Fengguang --- include/linux/radix-tree.h | 83 +++++++++++++++++++++++++++++++++++ lib/radix-tree.c | 104 ++++++++++++++++++++++++++++++++++----------- 2 files changed, 161 insertions(+), 26 deletions(-) --- linux-2.6.17-rc4-mm3.orig/include/linux/radix-tree.h +++ linux-2.6.17-rc4-mm3/include/linux/radix-tree.h @@ -49,7 +49,8 @@ do { \ } while (0) int radix_tree_insert(struct radix_tree_root *, unsigned long, void *); -void *radix_tree_lookup(struct radix_tree_root *, unsigned long); +void *__radix_tree_lookup_parent(struct radix_tree_root *, + unsigned long, unsigned int); void **radix_tree_lookup_slot(struct radix_tree_root *, unsigned long); void *radix_tree_delete(struct radix_tree_root *, unsigned long); unsigned int @@ -74,4 +75,17 @@ static inline void radix_tree_preload_en preempt_enable(); } +/** + * radix_tree_lookup - perform lookup operation on a radix tree + * @root: radix tree root + * @index: index key + * + * Lookup the item at the position @index in the radix tree @root. + */ +static inline void *radix_tree_lookup(struct radix_tree_root *root, + unsigned long index) +{ + return __radix_tree_lookup_parent(root, index, 0); +} + #endif /* _LINUX_RADIX_TREE_H */ --- linux-2.6.17-rc4-mm3.orig/lib/radix-tree.c +++ linux-2.6.17-rc4-mm3/lib/radix-tree.c @@ -309,36 +309,46 @@ int radix_tree_insert(struct radix_tree_ } EXPORT_SYMBOL(radix_tree_insert); -static inline void **__lookup_slot(struct radix_tree_root *root, - unsigned long index) +/** + * __radix_tree_lookup_parent - low level lookup routine + * @root: radix tree root + * @index: index key + * @level: stop at that many levels from the tree leaf + * + * Lookup the @level'th parent of the slot at @index in radix tree @root. + * The return value is: + * @level == 0: page at @index; + * @level == 1: the corresponding bottom level tree node; + * @level < height: (@level-1)th parent node of the bottom node + * that contains @index; + * @level >= height: the root node. + */ +void *__radix_tree_lookup_parent(struct radix_tree_root *root, + unsigned long index, unsigned int level) { unsigned int height, shift; - struct radix_tree_node **slot; + struct radix_tree_node *slot; height = root->height; if (index > radix_tree_maxindex(height)) return NULL; - if (height == 0 && root->rnode) - return (void **)&root->rnode; - shift = (height-1) * RADIX_TREE_MAP_SHIFT; - slot = &root->rnode; + slot = root->rnode; - while (height > 0) { - if (*slot == NULL) + while (height > level) { + if (slot == NULL) return NULL; - slot = (struct radix_tree_node **) - ((*slot)->slots + - ((index >> shift) & RADIX_TREE_MAP_MASK)); + slot = slot->slots[(index >> shift) & RADIX_TREE_MAP_MASK]; shift -= RADIX_TREE_MAP_SHIFT; height--; } - return (void **)slot; + return slot; } +EXPORT_SYMBOL(__radix_tree_lookup_parent); /** * radix_tree_lookup_slot - lookup a slot in a radix tree @@ -350,25 +360,15 @@ static inline void **__lookup_slot(struc */ void **radix_tree_lookup_slot(struct radix_tree_root *root, unsigned long index) { - return __lookup_slot(root, index); -} -EXPORT_SYMBOL(radix_tree_lookup_slot); + struct radix_tree_node *node; -/** - * radix_tree_lookup - perform lookup operation on a radix tree - * @root: radix tree root - * @index: index key - * - * Lookup the item at the position @index in the radix tree @root. - */ -void *radix_tree_lookup(struct radix_tree_root *root, unsigned long index) -{ - void **slot; + if (root->height == 0) + return &root->rnode; - slot = __lookup_slot(root, index); - return slot != NULL ? *slot : NULL; + node = __radix_tree_lookup_parent(root, index, 1); + return node ? node->slots + (index & RADIX_TREE_MAP_MASK) : NULL; } -EXPORT_SYMBOL(radix_tree_lookup); +EXPORT_SYMBOL(radix_tree_lookup_slot); /** * radix_tree_tag_set - set a tag on a radix tree node -- - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/