[Devel] [PATCH RH7 2/2] blk-cbt: fix in_use check in blk_cbt_release

[Pavel Tikhomirov]

Calling cpt_release_callback on cbt->count != 0 here is really strange
because cbt_page_alloc would anyway do it on decrementing count to zero,
but in opposite case where cbt->count == 0 we should call the callback
but we do not, let's fix it by reversing the condition.

We have a cbt->cache percpu allocation leak detected by kmemleak, which
might be caused by this uncalled release callback.

https://jira.sw.ru/browse/PSBM-141114

Signed-off-by: Pavel Tikhomirov <ptikhomirov at virtuozzo.com>
---
 block/blk-cbt.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/block/blk-cbt.c b/block/blk-cbt.c
index 2580ccabaa17..054c73c6ef9f 100644
--- a/block/blk-cbt.c
+++ b/block/blk-cbt.c
@@ -540,7 +540,7 @@ void blk_cbt_release(struct request_queue *q)
 	rcu_assign_pointer(q->cbt, NULL);
 	in_use = cbt->count;
 	spin_unlock(&cbt->lock);
-	if (in_use)
+	if (!in_use)
 		call_rcu(&cbt->rcu, &cbt_release_callback);
 }
 
-- 
2.37.3