Commit 05444118 authored Oct 15, 2019 by Tejun Heo Committed by Greg Kroah-Hartman Oct 29, 2019

blk-rq-qos: fix first node deletion of rq_qos_del()



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@kernel.org>
Cc: Josef Bacik <josef@toxicpanda.com>
Fixes: a7905043 ("blk-rq-qos: refactor out common elements of blk-wbt")
Cc: stable@vger.kernel.org # v4.19+
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent 2ada4030

block/blk-rq-qos.h

+5 −8

Original line number	Diff line number	Diff line
		@@ -80,16 +80,13 @@ static inline void rq_qos_add(struct request_queue q, struct rq_qos rqos)

		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;
		}
		}