Re: [Bug] double ->queue_rq() because of timeout in ->queue_rq()

[Bart Van Assche <bvanassche@acm.org>]

On 10/20/22 02:10, Ming Lei wrote:
 > [ ... ]

Hi Ming,

Fixing this in the block layer seems fine to me. A few comments:

> +	/* 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
> +	 */

Should the above comment follow the style of other comments in the block 
layer?

> +	blk_mq_wait_quiesce_done(q);
> +
> +	blk_mq_queue_tag_busy_iter(q, blk_mq_check_expired, &expired);

The above doesn't look sufficient to me since .queue_rq() may be called 
while blk_mq_queue_tag_busy_iter() is in progress. How about moving the 
blk_mq_wait_quiesce_done() call into blk_mq_check_expired() and 
preventing new .queue_rq() calls before the timeout handler is called?

Thanks,

Bart.