Re: [RFC PATCH 3/3] blk-mq: Remove generation seqeunce

Keith Busch
2018-07-18T21:33:21Z

On Wed, Jul 18, 2018 at 09:30:11PM +0000, Bart Van Assche wrote:
> On Wed, 2018-07-18 at 15:17 -0600, Keith Busch wrote:
> > There are not that many blk-mq drivers, so we can go through them all.
>
> I'm not sure that's the right approach. I think it is the responsibility of
> the block layer to handle races between completion handling and timeout
> handling and that this is not the responsibility of e.g. a block driver. If
> you look at e.g. the legacy block layer then you will see that it takes care
> of this race and that legacy block drivers do not have to worry about this
> race.

Reverting doesn't handle the race at all. It just ignores completions
and puts the responsibility on the drivers to handle the race because
that's what scsi wants to happen.