Re: [RFC PATCH for 8.1 4/6] vdpa: return errno in vhost_vdpa_get_vring_group error

[Stefano Garzarella]

On Fri, Mar 17, 2023 at 03:55:40PM +0100, Eugenio Pérez wrote:
> We need to tell in the caller, as some errors are expected in a normal
> workflow.  In particular, parent drivers in recent kernels with
> VHOST_BACKEND_F_IOTLB_ASID may not support vring groups.  In that case,
> -ENOTSUP is returned.

So, should we also avoid the error_report if we expect a failure?

Thanks,
Stefano

> This is the case of vp_vdpa in Linux 6.2.
>
> Next patches in this series will use that information to know if it must
> abort or not.
>
> Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
> ---
> net/vhost-vdpa.c | 9 +++++++++
> 1 file changed, 9 insertions(+)
>
> diff --git a/net/vhost-vdpa.c b/net/vhost-vdpa.c
> index 99904a0da7..4397c0d4b3 100644
> --- a/net/vhost-vdpa.c
> +++ b/net/vhost-vdpa.c
> @@ -361,6 +361,14 @@ static NetClientInfo net_vhost_vdpa_info = {
>         .check_peer_type = vhost_vdpa_check_peer_type,
> };
>
> +/**
> + * Get vring virtqueue group
> + *
> + * @device_fd  vdpa device fd
> + * @vq_index   Virtqueue index
> + *
> + * Return -errno in case of error, or vq group if success.
> + */
> static int64_t vhost_vdpa_get_vring_group(int device_fd, unsigned vq_index)
> {
>     struct vhost_vring_state state = {
> @@ -369,6 +377,7 @@ static int64_t vhost_vdpa_get_vring_group(int device_fd, 
> unsigned vq_index)
>     int r = ioctl(device_fd, VHOST_VDPA_GET_VRING_GROUP, &state);
>
>     if (unlikely(r < 0)) {
> +        r = -errno;
>         error_report("Cannot get VQ %u group: %s", vq_index,
>                      g_strerror(errno));
>         return r;
> --
> 2.31.1