On Wed, Oct 26, 2022 at 09:55:21AM +0800, Ming Lei wrote:
> @@ -1564,8 +1571,13 @@ static bool blk_mq_check_expired(struct request *rq, void *priv)
> * it was completed and reallocated as a new request after returning
> * from blk_mq_check_expired().
> */
> - if (blk_mq_req_expired(rq, next))
> + if (blk_mq_req_expired(rq, expired)) {
> + if (expired->check_only) {
> + expired->has_timedout_rq = true;
> + return false;
> + }
> blk_mq_rq_timed_out(rq);
> + }
> return true;
> }
>
> @@ -1573,7 +1585,10 @@ static void blk_mq_timeout_work(struct work_struct *work)
> {
> struct request_queue *q =
> container_of(work, struct request_queue, timeout_work);
> - unsigned long next = 0;
> + struct blk_expired_data expired = {
> + .check_only = true,
> + .timeout_start = jiffies,
> + };
> struct blk_mq_hw_ctx *hctx;
> unsigned long i;
>
> @@ -1593,10 +1608,24 @@ static void blk_mq_timeout_work(struct work_struct *work)
> if (!percpu_ref_tryget(&q->q_usage_counter))
> return;
>
> - blk_mq_queue_tag_busy_iter(q, blk_mq_check_expired, &next);
> + /* check if there is any timed-out request */
> + blk_mq_queue_tag_busy_iter(q, blk_mq_check_expired, &expired);
> + if (expired.has_timedout_rq) {
> + /*
> + * Before walking tags, we must ensure any submit started
> + * before the current time has finished. Since the submit
> + * uses srcu or rcu, wait for a synchronization point to
> + * ensure all running submits have finished
> + */
> + blk_mq_wait_quiesce_done(q);
> +
> + expired.check_only = false;
> + expired.next = 0;
> + blk_mq_queue_tag_busy_iter(q, blk_mq_check_expired, &expired);
I think it would be easier to follow with separate callbacks instead of
special casing for 'check_only'. One callback for checking timeouts, and
a different one for handling them?
