[PATCH RFC net-next v2 2/4] virtio/vsock: add VIRTIO_VSOCK_F_DGRAM feature bit

[Bobby Eshleman <bobby.eshleman@bytedance.com>]

This commit adds a feature bit for virtio vsock to support datagrams.
This commit should not be applied without first applying the commit
that implements datagrams for virtio.

Signed-off-by: Jiang Wang <jiang.wang@bytedance.com>
Signed-off-by: Bobby Eshleman <bobby.eshleman@bytedance.com>
---
 drivers/vhost/vsock.c             | 3 ++-
 include/uapi/linux/virtio_vsock.h | 1 +
 net/vmw_vsock/virtio_transport.c  | 8 ++++++--
 3 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c
index dff6ee1c479b..028cf079225e 100644
--- a/drivers/vhost/vsock.c
+++ b/drivers/vhost/vsock.c
@@ -32,7 +32,8 @@
 enum {
 	VHOST_VSOCK_FEATURES = VHOST_FEATURES |
 			       (1ULL << VIRTIO_F_ACCESS_PLATFORM) |
-			       (1ULL << VIRTIO_VSOCK_F_SEQPACKET)
+			       (1ULL << VIRTIO_VSOCK_F_SEQPACKET) |
+			       (1ULL << VIRTIO_VSOCK_F_DGRAM)
 };
 
 enum {
diff --git a/include/uapi/linux/virtio_vsock.h b/include/uapi/linux/virtio_vsock.h
index 331be28b1d30..0975b9c88292 100644
--- a/include/uapi/linux/virtio_vsock.h
+++ b/include/uapi/linux/virtio_vsock.h
@@ -40,6 +40,7 @@
 
 /* The feature bitmap for virtio vsock */
 #define VIRTIO_VSOCK_F_SEQPACKET	1	/* SOCK_SEQPACKET supported */
+#define VIRTIO_VSOCK_F_DGRAM		2	/* Host support dgram vsock */
 
 struct virtio_vsock_config {
 	__le64 guest_cid;
diff --git a/net/vmw_vsock/virtio_transport.c b/net/vmw_vsock/virtio_transport.c
index 582c6c0f788f..bb43eea9a6f9 100644
--- a/net/vmw_vsock/virtio_transport.c
+++ b/net/vmw_vsock/virtio_transport.c
@@ -29,6 +29,7 @@ static struct virtio_transport virtio_transport; /* forward declaration */
 struct virtio_vsock {
 	struct virtio_device *vdev;
 	struct virtqueue *vqs[VSOCK_VQ_MAX];
+	bool has_dgram;
 
 	/* Virtqueue processing is deferred to a workqueue */
 	struct work_struct tx_work;
@@ -640,7 +641,6 @@ static int virtio_vsock_probe(struct virtio_device *vdev)
 	}
 
 	vsock->vdev = vdev;
-
 	vsock->rx_buf_nr = 0;
 	vsock->rx_buf_max_nr = 0;
 	atomic_set(&vsock->queued_replies, 0);
@@ -657,6 +657,9 @@ static int virtio_vsock_probe(struct virtio_device *vdev)
 	if (virtio_has_feature(vdev, VIRTIO_VSOCK_F_SEQPACKET))
 		vsock->seqpacket_allow = true;
 
+	if (virtio_has_feature(vdev, VIRTIO_VSOCK_F_DGRAM))
+		vsock->has_dgram = true;
+
 	vdev->priv = vsock;
 
 	ret = virtio_vsock_vqs_init(vsock);
@@ -749,7 +752,8 @@ static struct virtio_device_id id_table[] = {
 };
 
 static unsigned int features[] = {
-	VIRTIO_VSOCK_F_SEQPACKET
+	VIRTIO_VSOCK_F_SEQPACKET,
+	VIRTIO_VSOCK_F_DGRAM
 };
 
 static struct virtio_driver virtio_vsock_driver = {

-- 
2.30.2