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Message-Id: <1460643410-30196-26-git-send-email-willy@linux.intel.com>
Date: Thu, 14 Apr 2016 10:16:46 -0400
From: Matthew Wilcox <willy@...ux.intel.com>
To: linux-kernel@...r.kernel.org,
Andrew Morton <akpm@...ux-foundation.org>
Cc: Matthew Wilcox <willy@...ux.intel.com>, linux-mm@...ck.org,
linux-fsdevel@...r.kernel.org,
Konstantin Khlebnikov <koct9i@...il.com>,
Kirill Shutemov <kirill.shutemov@...ux.intel.com>,
Jan Kara <jack@...e.com>, Neil Brown <neilb@...e.de>,
Ross Zwisler <ross.zwisler@...ux.intel.com>
Subject: [PATCH v2 25/29] radix-tree: Fix radix_tree_create for sibling entries
If the radix tree user attempted to insert a colliding entry with an
existing multiorder entry, then radix_tree_create() could encounter
a sibling entry when walking down the tree to look for a slot.
Use radix_tree_descend() to fix the problem, and add a test-case to make
sure the problem doesn't come back in future.
Signed-off-by: Matthew Wilcox <willy@...ux.intel.com>
Reviewed-by: Ross Zwisler <ross.zwisler@...ux.intel.com>
---
lib/radix-tree.c | 4 ++--
tools/testing/radix-tree/multiorder.c | 5 +++++
2 files changed, 7 insertions(+), 2 deletions(-)
diff --git a/lib/radix-tree.c b/lib/radix-tree.c
index b1ca744..9b5d8a9 100644
--- a/lib/radix-tree.c
+++ b/lib/radix-tree.c
@@ -548,9 +548,9 @@ int __radix_tree_create(struct radix_tree_root *root, unsigned long index,
/* Go a level down */
height--;
shift -= RADIX_TREE_MAP_SHIFT;
- offset = (index >> shift) & RADIX_TREE_MAP_MASK;
node = indirect_to_ptr(slot);
- slot = node->slots[offset];
+ offset = (index >> shift) & RADIX_TREE_MAP_MASK;
+ offset = radix_tree_descend(node, &slot, offset);
}
#ifdef CONFIG_RADIX_TREE_MULTIORDER
diff --git a/tools/testing/radix-tree/multiorder.c b/tools/testing/radix-tree/multiorder.c
index 1b6fc9b..fc93457 100644
--- a/tools/testing/radix-tree/multiorder.c
+++ b/tools/testing/radix-tree/multiorder.c
@@ -135,6 +135,11 @@ static void multiorder_check(unsigned long index, int order)
item_check_absent(&tree, i);
for (i = max; i < 2*max; i++)
item_check_absent(&tree, i);
+ for (i = min; i < max; i++) {
+ static void *entry = (void *)
+ (0xA0 | RADIX_TREE_EXCEPTIONAL_ENTRY);
+ assert(radix_tree_insert(&tree, i, entry) == -EEXIST);
+ }
assert(item_delete(&tree, index) != 0);
--
2.8.0.rc3
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