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

[Keith Busch]

On Mon, Apr 19, 2021 at 10:27:42AM -0700, Yuanyuan Zhong wrote:
> On Mon, Apr 19, 2021 at 8:14 AM Keith Busch <kbusch at 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.

I'm not sure it can be turned into a common pattern. The callbacks are
implementation specific.
 
> > > >
> > > > > 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.

---
diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index b57157106cac..a0fb9ad132af 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -949,6 +949,9 @@ static void nvme_end_sync_rq(struct request *rq, blk_status_t error)
 	struct completion *waiting = rq->end_io_data;
 
 	rq->end_io_data = NULL;
+	if (error && !nvme_req(rq)->status)
+		nvme_req(rq)->status = blk_status_to_errno(error);
 	complete(waiting);
 }
 
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