Re: [RFC PATCH 1/1] virtio-blk: process block layer timedout request

[Stefan Hajnoczi]

On Mon, 8 Jan 2024 at 22:33, Chaitanya Kulkarni <chaitanyak@xxxxxxxxxx> wrote:
> On 11/30/23 17:25, Stefan Hajnoczi wrote:
> > On Wed, Nov 29, 2023 at 11:01:33PM -0800, Chaitanya Kulkarni wrote:
> >> diff --git a/include/uapi/linux/virtio_blk.h b/include/uapi/linux/virtio_blk.h
> >> index 3744e4da1b2a..ed864195ab26 100644
> >> --- a/include/uapi/linux/virtio_blk.h
> >> +++ b/include/uapi/linux/virtio_blk.h
> >> @@ -317,6 +317,7 @@ struct virtio_scsi_inhdr {
> >>   #define VIRTIO_BLK_S_OK            0
> >>   #define VIRTIO_BLK_S_IOERR 1
> >>   #define VIRTIO_BLK_S_UNSUPP        2
> >> +#define VIRTIO_BLK_S_TIMEOUT        3
> > The structs and constants in this header file come from the VIRTIO
> > specification. Anything changed in this file must first be accepted into
> > the VIRTIO spec because this is the hardware interface definition.
> >
> > VIRTIO_BLK_S_TIMEOUT seems to be synthetic value that is purely used by
> > software, not the device. Maybe there is no need to update the spec.
> > Just avoid using in_hdr.status to signal timeouts and use a separate
> > flag/field instead in a block layer or virtio_blk driver request struct.
>
> It is a specific error hence I've added that on the similar lines,
> do you have a specific field in mind that you would prefer ?

I didn't have a specific flag or field in mind, but it's probably no
longer necessary in v2 because the code needs to wait for the device
to complete the request anyway.

Stefan