Re: [RFC PATCH 2/3] blk-mq: Fix timeout and state order

Christoph Hellwig
2018-05-22T15:24:37Z

On Mon, May 21, 2018 at 05:11:30PM -0600, Keith Busch wrote:
> The block layer had been setting the state to in-flight prior to updating
> the timer. This is the wrong order since the timeout handler could observe
> the in-flight state with the older timeout, believing the request had
> expired when in fact it is just getting started.
>
> Signed-off-by: Keith Busch <keith.busch@intel.com>

The way I understood Barts comments to my comments on his patch we
actually need the two updates to be atomic. I haven't had much time
to follow up, but I'd like to hear Barts opinion. Either way we
clearly need to document our assumptions here in comments.