Re: [PATCH 2/2] nvme: use return value from blk_execute_rq()

[Yuanyuan Zhong <yzhong@purestorage.com>]

On Mon, Apr 19, 2021 at 8:14 AM Keith Busch <kbusch@kernel.org> wrote:
>
> On Mon, Apr 19, 2021 at 09:16:05AM +0200, Christoph Hellwig wrote:
> > On Sat, Apr 17, 2021 at 02:17:35AM +0900, Keith Busch wrote:
> > > On Fri, Apr 16, 2021 at 10:12:11AM -0700, Yuanyuan Zhong wrote:
> > > > >         if (poll)
> > > > >                 nvme_execute_rq_polled(req->q, NULL, req, at_head);
> > > > You may need to audit other completion handlers for blk_execute_rq_nowait().
> > >
> > > Why? Those callers already provide their own callback that directly get
> > > the error.

See below clarification. I was wondering whether the way you were going to
propose for nvme_end_sync_rq() would establish new convention for other
blk_execute_rq_nowait() completion handlers implementation.

> > >
> > > > How to get error ret from polled rq?
> > >
> > > Please see nvme_end_sync_rq() for that driver's polled handler callback.
> > > It already has the error.
> >
> > But it never looks at it..
>
> The question was how to get ret. I didn't mean to imply the example was
> actually using it. :)

The question was how to let nvme_end_sync_rq() propagate the blk_status_t
error to the ret for __nvme_submit_sync_cmd(). That's part of the problem
here: __nvme_submit_sync_cmd() may return success for a command that
failed submission.

-- 
Regards,
Yuanyuan Zhong