On Wed, 2018-04-11 at 10:11 +0800, Ming Lei wrote:
> On Tue, Apr 10, 2018 at 03:01:57PM -0600, Bart Van Assche wrote:
> > The blk-mq timeout handling code ignores completions that occur after
> > blk_mq_check_expired() has been called and before blk_mq_rq_timed_out()
> > has reset rq->aborted_gstate. If a block driver timeout handler always
> > returns BLK_EH_RESET_TIMER then the result will be that the request
> > never terminates.
>
> Under this situation:
>
> IMO, if this request has been handled by driver's irq handler, and if
> driver's .timeout still returns BLK_EH_RESET_TIMER, it is driver's bug,
> and the correct return value should be BLK_EH_HANDLED.
Maybe. In the virtio-scsi driver I found the following:
/*
* The host guarantees to respond to each command, although I/O
* latencies might be higher than on bare metal. Reset the timer
* unconditionally to give the host a chance to perform EH.
*/
static enum blk_eh_timer_return virtscsi_eh_timed_out(struct scsi_cmnd *scmnd)
{
return BLK_EH_RESET_TIMER;
}
Bart.