Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932464AbcDNOWK (ORCPT ); Thu, 14 Apr 2016 10:22:10 -0400 Received: from mga09.intel.com ([134.134.136.24]:35979 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756590AbcDNOWD (ORCPT ); Thu, 14 Apr 2016 10:22:03 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.24,485,1455004800"; d="scan'208";a="686240908" From: Matthew Wilcox To: linux-kernel@vger.kernel.org, Andrew Morton Cc: Matthew Wilcox , linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, Konstantin Khlebnikov , Kirill Shutemov , Jan Kara , Neil Brown , Ross Zwisler Subject: [PATCH v2 14/29] radix-tree: Fix extending the tree for multi-order entries at offset 0 Date: Thu, 14 Apr 2016 10:16:35 -0400 Message-Id: <1460643410-30196-15-git-send-email-willy@linux.intel.com> X-Mailer: git-send-email 2.8.0.rc3 In-Reply-To: <1460643410-30196-1-git-send-email-willy@linux.intel.com> References: <1460643410-30196-1-git-send-email-willy@linux.intel.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2938 Lines: 92 The current code will insert entries at each level, as if we're going to add a new entry at the bottom level, so we then get an -EEXIST when we try to insert the entry into the tree. The best way to fix this is to not check 'order' when inserting into an empty tree. We still need to 'extend' the tree to the height necessary for the maximum index corresponding to this entry, so pass that value to radix_tree_extend() rather than the index we're asked to create, or we won't create a tree that's deep enough. Signed-off-by: Matthew Wilcox Reviewed-by: Ross Zwisler --- lib/radix-tree.c | 28 +++++++++++++++++----------- 1 file changed, 17 insertions(+), 11 deletions(-) diff --git a/lib/radix-tree.c b/lib/radix-tree.c index 272ce81..f13ddbb 100644 --- a/lib/radix-tree.c +++ b/lib/radix-tree.c @@ -432,7 +432,7 @@ static unsigned radix_tree_load_root(struct radix_tree_root *root, * Extend a radix tree so it can store key @index. */ static int radix_tree_extend(struct radix_tree_root *root, - unsigned long index, unsigned order) + unsigned long index) { struct radix_tree_node *node; struct radix_tree_node *slot; @@ -444,7 +444,7 @@ static int radix_tree_extend(struct radix_tree_root *root, while (index > radix_tree_maxindex(height)) height++; - if ((root->rnode == NULL) && (order == 0)) { + if (root->rnode == NULL) { root->height = height; goto out; } @@ -467,7 +467,7 @@ static int radix_tree_extend(struct radix_tree_root *root, node->count = 1; node->parent = NULL; slot = root->rnode; - if (radix_tree_is_indirect_ptr(slot) && newheight > 1) { + if (radix_tree_is_indirect_ptr(slot)) { slot = indirect_to_ptr(slot); slot->parent = node; slot = ptr_to_indirect(slot); @@ -478,7 +478,7 @@ static int radix_tree_extend(struct radix_tree_root *root, root->height = newheight; } while (height > root->height); out: - return 0; + return height * RADIX_TREE_MAP_SHIFT; } /** @@ -503,20 +503,26 @@ int __radix_tree_create(struct radix_tree_root *root, unsigned long index, void ***slotp) { struct radix_tree_node *node = NULL, *slot; + unsigned long maxindex; unsigned int height, shift, offset; - int error; + unsigned long max = index | ((1UL << order) - 1); + + shift = radix_tree_load_root(root, &slot, &maxindex); /* Make sure the tree is high enough. */ - if (index > radix_tree_maxindex(root->height)) { - error = radix_tree_extend(root, index, order); - if (error) + if (max > maxindex) { + int error = radix_tree_extend(root, max); + if (error < 0) return error; + shift = error; + slot = root->rnode; + if (order == shift) { + shift += RADIX_TREE_MAP_SHIFT; + root->height++; + } } - slot = root->rnode; - height = root->height; - shift = height * RADIX_TREE_MAP_SHIFT; offset = 0; /* uninitialised var warning */ while (shift > order) { -- 2.8.0.rc3