[PATCH 10/30] radix-tree: Fix sibling entry insertion

Matthew Wilcox
2016-04-06T21:31:04Z

The subtraction was the wrong way round, leading to undefined behaviour
(shift by an amount larger than the size of the type).

Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com>
---
lib/radix-tree.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/lib/radix-tree.c b/lib/radix-tree.c
index 40343f28a705..42a0492b2ba2 100644
--- a/lib/radix-tree.c
+++ b/lib/radix-tree.c
@@ -526,8 +526,8 @@ int __radix_tree_create(struct radix_tree_root *root, unsigned long index,

#ifdef CONFIG_RADIX_TREE_MULTIORDER
/* Insert pointers to the canonical entry */
- if ((shift - order) > 0) {
- int i, n = 1 << (shift - order);
+ if (order > shift) {
+ int i, n = 1 << (order - shift);
offset = offset & ~(n - 1);
slot = ptr_to_indirect(&node->slots[offset]);
for (i = 0; i < n; i++) {
--
2.8.0.rc3