radix_tree_locate_item() is often returning the wrong index, causing
swapoff of shmem to hang because it cannot find the swap entry there.
__locate()'s use of base is bogus, it adds an offset twice into index.
Signed-off-by: Hugh Dickins <hughd@xxxxxxxxxx>
---
Fix to radix-tree-rewrite-radix_tree_locate_item.patch
lib/radix-tree.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
--- 4.6-rc5-mm1/lib/radix-tree.c 2016-04-30 22:55:06.067184898 -0700
+++ linux/lib/radix-tree.c 2016-05-01 18:52:06.668085420 -0700
@@ -1254,15 +1254,14 @@ struct locate_info {
static unsigned long __locate(struct radix_tree_node *slot, void *item,
unsigned long index, struct locate_info *info)
{
- unsigned long base, i;
+ unsigned long i;
do {
unsigned int shift = slot->shift;
- base = index & ~((1UL << shift) - 1);
for (i = (index >> shift) & RADIX_TREE_MAP_MASK;
i < RADIX_TREE_MAP_SIZE;
- i++, index = base + (i << shift)) {
+ i++, index += (1UL << shift)) {
struct radix_tree_node *node =
rcu_dereference_raw(slot->slots[i]);
if (node == RADIX_TREE_RETRY)
--
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