From: Tejun Heo <tj@xxxxxxxxxx>
commit 307f4065b9d7c1e887e8bdfb2487e4638559fea1 upstream.
rq_qos_del() incorrectly assigns the node being deleted to the head if
it was the first on the list in the !prev path. Fix it by iterating
with ** instead.
Signed-off-by: Tejun Heo <tj@xxxxxxxxxx>
Cc: Josef Bacik <josef@xxxxxxxxxxxxxx>
Fixes: a79050434b45 ("blk-rq-qos: refactor out common elements of blk-wbt")
Cc: stable@xxxxxxxxxxxxxxx # v4.19+
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
block/blk-rq-qos.h | 13 +++++--------
1 file changed, 5 insertions(+), 8 deletions(-)
--- a/block/blk-rq-qos.h
+++ b/block/blk-rq-qos.h
@@ -103,16 +103,13 @@ static inline void rq_qos_add(struct req
static inline void rq_qos_del(struct request_queue *q, struct rq_qos *rqos)
{
- struct rq_qos *cur, *prev = NULL;
- for (cur = q->rq_qos; cur; cur = cur->next) {
- if (cur == rqos) {
- if (prev)
- prev->next = rqos->next;
- else
- q->rq_qos = cur;
+ struct rq_qos **cur;
+
+ for (cur = &q->rq_qos; *cur; cur = &(*cur)->next) {
+ if (*cur == rqos) {
+ *cur = rqos->next;
break;
}
- prev = cur;
}
blk_mq_debugfs_unregister_rqos(rqos);
