On 12/18/18 1:09 AM, Ming Lei wrote: > On Tue, Dec 18, 2018 at 07:47:39AM +0100, Christoph Hellwig wrote: >> On Mon, Dec 17, 2018 at 09:34:55PM -0700, Jens Axboe wrote: >>> On 12/17/18 9:15 PM, Ming Lei wrote: >>>> The queue mapping of type poll only exists when set->map[HCTX_TYPE_POLL].nr_queues >>>> is bigger than zero, so enhance the constraint by checking .nr_queues of type poll >>>> before enabling IO poll. >>>> >>>> Otherwise IO race & timeout can be observed when running block/007. >>> >>> Looks good to me, but we might consider having a helper for this, since >>> we have this check in 3 places now. But for now this is good, thanks >>> Ming. >> >> Jens, if you want this I can drop the nvme patch to set nr_maps to 2 >> as it wouldn't be needed. Not sure which one is more elegant, but >> I guess Mings version is a little more fool proof. > > For READ queue type, its .nr_maps can be 3 and .nr_queues is zero, so > if check on the two queue type is kept as consistent, we may get good > code readability, IMO. > > As Jens mentioned, we may introduce blk_mq_queue_type_supported() helper > to cover both. I think that would be preferable. -- Jens Axboe
