[PATCHv3 1/9] nvme: Sync request queues on reset

[keith.busch@linux.intel.com (Keith Busch)]

On Thu, May 31, 2018@02:25:54AM +0300, Sagi Grimberg wrote:
> > > > At least in the current blk-mq timeout handling, returning RESET_TIMER
> > > > presents other challenges for the reset handler: the timer may have
> > > > reclaimed the request that reset_work is trying to complete.
> > > 
> > > why would that be true if BLK_EH_RESET_TIMER was returned ?
> > 
> > That return rearms the timer for triggering timeout handling, and
> > when that timeout handling triggers, your reset work won't be able to
> > complete the request. You're basically relying on the timer being high
> > enough that your reset work beats the timer to the completion. That may
> > be sufficient in practice most of the time.
> 
> Why? the timeout handler would reset the timer yet again.

Right, the timeout hanlder resets the timer on a request the driver believes
it already completed.