From patchwork Wed Apr 6 21:21:22 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Matthew Wilcox X-Patchwork-Id: 8765981 Return-Path: X-Original-To: patchwork-linux-fsdevel@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 02EFBC0553 for ; Wed, 6 Apr 2016 21:28:05 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 97F4220123 for ; Wed, 6 Apr 2016 21:28:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BB6C22010F for ; Wed, 6 Apr 2016 21:28:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753992AbcDFVVz (ORCPT ); Wed, 6 Apr 2016 17:21:55 -0400 Received: from mga02.intel.com ([134.134.136.20]:17416 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753913AbcDFVVy (ORCPT ); Wed, 6 Apr 2016 17:21:54 -0400 Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by orsmga101.jf.intel.com with ESMTP; 06 Apr 2016 14:21:52 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.24,448,1455004800"; d="scan'208";a="939802024" Received: from rtnitta-mobl.amr.corp.intel.com (HELO thog.int.wil.cx) ([10.252.140.190]) by fmsmga001.fm.intel.com with SMTP; 06 Apr 2016 14:21:51 -0700 Received: by thog.int.wil.cx (Postfix, from userid 1000) id 67C9860322; Wed, 6 Apr 2016 17:21:48 -0400 (EDT) From: Matthew Wilcox To: linux-kernel@vger.kernel.org, Andrew Morton Cc: Matthew Wilcox , Ross Zwisler , linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, Konstantin Khlebnikov , Kirill Shutemov , Jan Kara , Neil Brown Subject: [PATCH 13/30] radix-tree: Introduce radix_tree_load_root() Date: Wed, 6 Apr 2016 17:21:22 -0400 Message-Id: <1459977699-2349-14-git-send-email-willy@linux.intel.com> X-Mailer: git-send-email 2.8.0.rc3 In-Reply-To: <1459977699-2349-1-git-send-email-willy@linux.intel.com> References: <1459977699-2349-1-git-send-email-willy@linux.intel.com> Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org X-Spam-Status: No, score=-7.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP All the tree walking functions start with some variant of this code; centralise it in one place so we're not chasing subtly different bugs everywhere. Signed-off-by: Matthew Wilcox Reviewed-by: Ross Zwisler --- lib/radix-tree.c | 23 +++++++++++++++++++++++ 1 file changed, 23 insertions(+) diff --git a/lib/radix-tree.c b/lib/radix-tree.c index f2a314cf42cc..b3a7e6cd5773 100644 --- a/lib/radix-tree.c +++ b/lib/radix-tree.c @@ -405,6 +405,29 @@ static inline unsigned long radix_tree_maxindex(unsigned int height) return height_to_maxindex[height]; } +static inline unsigned long node_maxindex(struct radix_tree_node *node) +{ + return radix_tree_maxindex(node->path & RADIX_TREE_HEIGHT_MASK); +} + +static unsigned radix_tree_load_root(struct radix_tree_root *root, + struct radix_tree_node **nodep, unsigned long *maxindex) +{ + struct radix_tree_node *node = rcu_dereference_raw(root->rnode); + + *nodep = node; + + if (likely(radix_tree_is_indirect_ptr(node))) { + node = indirect_to_ptr(node); + *maxindex = node_maxindex(node); + return (node->path & RADIX_TREE_HEIGHT_MASK) * + RADIX_TREE_MAP_SHIFT; + } + + *maxindex = 0; + return 0; +} + /* * Extend a radix tree so it can store key @index. */