virtio_net: use control_buf for coalesce params

Commit 699b045a ("net: virtio_net: notifications coalescing
support") added coalescing command support for virtio_net. However,
the coalesce commands are using buffers on the stack, which is causing
the device to see DMA errors. There should also be a complaint from
check_for_stack() in debug_dma_map_xyz(). Fix this by adding and using
coalesce params from the control_buf struct, which aligns with other
commands.

Cc: stable@vger.kernel.org
Fixes: 699b045a ("net: virtio_net: notifications coalescing support")
Reviewed-by: Shannon Nelson <shannon.nelson@amd.com>
Signed-off-by: Allen Hubbe <allen.hubbe@amd.com>
Signed-off-by: Brett Creeley <brett.creeley@amd.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Reviewed-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Link: https://lore.kernel.org/r/20230605195925.51625-1-brett.creeley@amd.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/virtio_net.c

@@ -205,6 +205,8 @@ struct control_buf {
 	__virtio16 vid;
 	__virtio64 offloads;
 	struct virtio_net_ctrl_rss rss;
+	struct virtio_net_ctrl_coal_tx coal_tx;
+	struct virtio_net_ctrl_coal_rx coal_rx;
 };
 
 struct virtnet_info {
@@ -2934,12 +2936,10 @@ static int virtnet_send_notf_coal_cmds(struct virtnet_info *vi,
 				       struct ethtool_coalesce *ec)
 {
 	struct scatterlist sgs_tx, sgs_rx;
-	struct virtio_net_ctrl_coal_tx coal_tx;
-	struct virtio_net_ctrl_coal_rx coal_rx;
 
-	coal_tx.tx_usecs = cpu_to_le32(ec->tx_coalesce_usecs);
-	coal_tx.tx_max_packets = cpu_to_le32(ec->tx_max_coalesced_frames);
-	sg_init_one(&sgs_tx, &coal_tx, sizeof(coal_tx));
+	vi->ctrl->coal_tx.tx_usecs = cpu_to_le32(ec->tx_coalesce_usecs);
+	vi->ctrl->coal_tx.tx_max_packets = cpu_to_le32(ec->tx_max_coalesced_frames);
+	sg_init_one(&sgs_tx, &vi->ctrl->coal_tx, sizeof(vi->ctrl->coal_tx));
 
 	if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_NOTF_COAL,
 				  VIRTIO_NET_CTRL_NOTF_COAL_TX_SET,
@@ -2950,9 +2950,9 @@ static int virtnet_send_notf_coal_cmds(struct virtnet_info *vi,
 	vi->tx_usecs = ec->tx_coalesce_usecs;
 	vi->tx_max_packets = ec->tx_max_coalesced_frames;
 
-	coal_rx.rx_usecs = cpu_to_le32(ec->rx_coalesce_usecs);
-	coal_rx.rx_max_packets = cpu_to_le32(ec->rx_max_coalesced_frames);
-	sg_init_one(&sgs_rx, &coal_rx, sizeof(coal_rx));
+	vi->ctrl->coal_rx.rx_usecs = cpu_to_le32(ec->rx_coalesce_usecs);
+	vi->ctrl->coal_rx.rx_max_packets = cpu_to_le32(ec->rx_max_coalesced_frames);
+	sg_init_one(&sgs_rx, &vi->ctrl->coal_rx, sizeof(vi->ctrl->coal_rx));
 
 	if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_NOTF_COAL,
 				  VIRTIO_NET_CTRL_NOTF_COAL_RX_SET,