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 <epere...@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