[PATCH AUTOSEL 6.10 09/13] virtio-net: check feature before configuring the vq coalescing command

[Sasha Levin <sashal@kernel.org>]

From: Heng Qi <hengqi@linux.alibaba.com>

[ Upstream commit b50f2af9fbc5c00103ca8b72752b15310bd77762 ]

Virtio spec says:

	The driver MUST have negotiated the VIRTIO_NET_F_VQ_NOTF_COAL
	feature when issuing commands VIRTIO_NET_CTRL_NOTF_COAL_VQ_SET
	and VIRTIO_NET_CTRL_NOTF_COAL_VQ_GET.

So we add the feature negotiation check to
virtnet_send_{r,t}x_ctrl_coal_vq_cmd as a basis for the next bugfix patch.

Suggested-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Heng Qi <hengqi@linux.alibaba.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/net/virtio_net.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 5161e7efda2cb..08a83944dcc0a 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -3172,6 +3172,9 @@ static int virtnet_send_rx_ctrl_coal_vq_cmd(struct virtnet_info *vi,
 {
 	int err;
 
+	if (!virtio_has_feature(vi->vdev, VIRTIO_NET_F_VQ_NOTF_COAL))
+		return -EOPNOTSUPP;
+
 	err = virtnet_send_ctrl_coal_vq_cmd(vi, rxq2vq(queue),
 					    max_usecs, max_packets);
 	if (err)
@@ -3189,6 +3192,9 @@ static int virtnet_send_tx_ctrl_coal_vq_cmd(struct virtnet_info *vi,
 {
 	int err;
 
+	if (!virtio_has_feature(vi->vdev, VIRTIO_NET_F_VQ_NOTF_COAL))
+		return -EOPNOTSUPP;
+
 	err = virtnet_send_ctrl_coal_vq_cmd(vi, txq2vq(queue),
 					    max_usecs, max_packets);
 	if (err)
-- 
2.43.0