Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1161001AbVIBGas (ORCPT ); Fri, 2 Sep 2005 02:30:48 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1161002AbVIBGar (ORCPT ); Fri, 2 Sep 2005 02:30:47 -0400 Received: from smtp207.mail.sc5.yahoo.com ([216.136.129.97]:36943 "HELO smtp207.mail.sc5.yahoo.com") by vger.kernel.org with SMTP id S1161001AbVIBGaq (ORCPT ); Fri, 2 Sep 2005 02:30:46 -0400 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=yahoo.com.au; h=Received:Message-ID:Date:From:User-Agent:X-Accept-Language:MIME-Version:To:Subject:References:In-Reply-To:Content-Type; b=wC2M79PYvioXhDGvVOynPrkpSLt332ckY8lKQmVK35ho+ppyGiPk8/0Lj1j7hAX2uLdl0h2Po4BbhBkqjVPFcEGsN+XcRCTVpSD+7g/r79+skkL/6JVNHLOJBBg+9nxYEcLT6m/LpU9/piRHPPHhOIZkRJYLzLDOKvHEXRm2kdc= ; Message-ID: <4317F1A2.8030605@yahoo.com.au> Date: Fri, 02 Sep 2005 16:30:58 +1000 From: Nick Piggin User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7.10) Gecko/20050802 Debian/1.7.10-1 X-Accept-Language: en MIME-Version: 1.0 To: Linux Memory Management , linux-kernel Subject: [PATCH 2.6.13] lockless pagecache 4/7 References: <4317F071.1070403@yahoo.com.au> <4317F0F9.1080602@yahoo.com.au> <4317F136.4040601@yahoo.com.au> <4317F17F.5050306@yahoo.com.au> In-Reply-To: <4317F17F.5050306@yahoo.com.au> Content-Type: multipart/mixed; boundary="------------090202060603040101050109" Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3403 Lines: 106 This is a multi-part message in MIME format. --------------090202060603040101050109 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit 4/7 -- SUSE Labs, Novell Inc. --------------090202060603040101050109 Content-Type: text/plain; name="radix-tree-lookup_slot.patch" Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="radix-tree-lookup_slot.patch" From: Hans Reiser Reiser4 uses radix trees to solve a trouble reiser4_readdir has serving nfs requests. Unfortunately, radix tree api lacks an operation suitable for modifying existing entry. This patch adds radix_tree_lookup_slot which returns pointer to found item within the tree. That location can be then updated. Index: linux-2.6/include/linux/radix-tree.h =================================================================== --- linux-2.6.orig/include/linux/radix-tree.h +++ linux-2.6/include/linux/radix-tree.h @@ -46,6 +46,7 @@ do { \ 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_slot(struct radix_tree_root *, unsigned long); void *radix_tree_delete(struct radix_tree_root *, unsigned long); unsigned int radix_tree_gang_lookup(struct radix_tree_root *root, void **results, Index: linux-2.6/lib/radix-tree.c =================================================================== --- linux-2.6.orig/lib/radix-tree.c +++ linux-2.6/lib/radix-tree.c @@ -276,14 +276,8 @@ int radix_tree_insert(struct radix_tree_ } EXPORT_SYMBOL(radix_tree_insert); -/** - * 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) +static inline void **__lookup_slot(struct radix_tree_root *root, + unsigned long index) { unsigned int height, shift; struct radix_tree_node **slot; @@ -306,7 +300,36 @@ void *radix_tree_lookup(struct radix_tre height--; } - return *slot; + return (void **)slot; +} + +/** + * radix_tree_lookup_slot - lookup a slot in a radix tree + * @root: radix tree root + * @index: index key + * + * Lookup the slot corresponding to the position @index in the radix tree + * @root. This is useful for update-if-exists operations. + */ +void **radix_tree_lookup_slot(struct radix_tree_root *root, unsigned long index) +{ + return __lookup_slot(root, index); +} +EXPORT_SYMBOL(radix_tree_lookup_slot); + +/** + * 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; + + slot = __lookup_slot(root, index); + return slot != NULL ? *slot : NULL; } EXPORT_SYMBOL(radix_tree_lookup); --------------090202060603040101050109-- Send instant messages to your online friends http://au.messenger.yahoo.com - 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/