Re: [PATCH for 8.1 v2 4/6] vdpa: return errno in vhost_vdpa_get_vring_group error

[Stefano Garzarella <sgarzare@redhat.com>]

On Thu, Mar 23, 2023 at 08:54:02PM +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.
>
>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.  Also, next patches return properly an errp instead of
>printing with error_report.
>
>Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
>---
> net/vhost-vdpa.c | 9 +++++++++
> 1 file changed, 9 insertions(+)

Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>

>
>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
>