From: Matthew Wilcox <willy@xxxxxxxxxxxxxxx>
Subject: 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@xxxxxxxxxxxxxxx>
Reviewed-by: Ross Zwisler <ross.zwisler@xxxxxxxxxxxxxxx>
Cc: Konstantin Khlebnikov <koct9i@xxxxxxxxx>
Cc: Kirill Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: Jan Kara <jack@xxxxxxxx>
Cc: Neil Brown <neilb@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
lib/radix-tree.c | 4 ++--
tools/testing/radix-tree/multiorder.c | 5 +++++
2 files changed, 7 insertions(+), 2 deletions(-)
diff -puN lib/radix-tree.c~radix-tree-fix-radix_tree_create-for-sibling-entries lib/radix-tree.c
--- a/lib/radix-tree.c~radix-tree-fix-radix_tree_create-for-sibling-entries
+++ a/lib/radix-tree.c
@@ -548,9 +548,9 @@ int __radix_tree_create(struct radix_tre
/* 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 -puN tools/testing/radix-tree/multiorder.c~radix-tree-fix-radix_tree_create-for-sibling-entries tools/testing/radix-tree/multiorder.c
--- a/tools/testing/radix-tree/multiorder.c~radix-tree-fix-radix_tree_create-for-sibling-entries
+++ a/tools/testing/radix-tree/multiorder.c
@@ -135,6 +135,11 @@ static void multiorder_check(unsigned lo
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);
_
--
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