[RFC PATCH v2 6/8] virtio/vsock: enable zerocopy callback

[Arseniy Krasnov <AVKrasnov@xxxxxxxxxxxxxx>]

This adds zerocopy callback for virtio transport.

Signed-off-by: Arseniy Krasnov <AVKrasnov@xxxxxxxxxxxxxx>
---
 net/vmw_vsock/virtio_transport.c | 43 ++++++++++++++++++++++++++++++++
 1 file changed, 43 insertions(+)

diff --git a/net/vmw_vsock/virtio_transport.c b/net/vmw_vsock/virtio_transport.c
index 19909c1e9ba3..2e05b01caa94 100644
--- a/net/vmw_vsock/virtio_transport.c
+++ b/net/vmw_vsock/virtio_transport.c
@@ -64,6 +64,7 @@ struct virtio_vsock {
 
 	u32 guest_cid;
 	bool seqpacket_allow;
+	bool zerocopy_rx_on;
 };
 
 static u32 virtio_transport_get_local_cid(void)
@@ -455,6 +456,45 @@ static void virtio_vsock_rx_done(struct virtqueue *vq)
 
 static bool virtio_transport_seqpacket_allow(u32 remote_cid);
 
+static int
+virtio_transport_zerocopy_set(struct vsock_sock *vsk, bool enable)
+{
+	struct virtio_vsock *vsock;
+
+	rcu_read_lock();
+	vsock = rcu_dereference(the_virtio_vsock);
+
+	if (!vsock) {
+		rcu_read_unlock();
+		return -ENODEV;
+	}
+
+	vsock->zerocopy_rx_on = enable;
+	rcu_read_unlock();
+
+	return 0;
+}
+
+static int
+virtio_transport_zerocopy_get(struct vsock_sock *vsk)
+{
+	struct virtio_vsock *vsock;
+	bool res;
+
+	rcu_read_lock();
+	vsock = rcu_dereference(the_virtio_vsock);
+
+	if (!vsock) {
+		rcu_read_unlock();
+		return -ENODEV;
+	}
+
+	res = vsock->zerocopy_rx_on;
+	rcu_read_unlock();
+
+	return res;
+}
+
 static struct virtio_transport virtio_transport = {
 	.transport = {
 		.module                   = THIS_MODULE,
@@ -480,6 +520,9 @@ static struct virtio_transport virtio_transport = {
 		.stream_rcvhiwat          = virtio_transport_stream_rcvhiwat,
 		.stream_is_active         = virtio_transport_stream_is_active,
 		.stream_allow             = virtio_transport_stream_allow,
+		.zerocopy_dequeue         = virtio_transport_zerocopy_dequeue,
+		.rx_zerocopy_set	  = virtio_transport_zerocopy_set,
+		.rx_zerocopy_get	  = virtio_transport_zerocopy_get,
 
 		.seqpacket_dequeue        = virtio_transport_seqpacket_dequeue,
 		.seqpacket_enqueue        = virtio_transport_seqpacket_enqueue,
-- 
2.25.1