Re: [PATCH net-next v5 1/5] vsock/virtio: split socket lookup from locked RX processing

[Stefano Garzarella <sgarzare@redhat.com>]

On Tue, Nov 03, 2026 at 12:11:30PM +0800, Jia Jia wrote:
>Split virtio_transport_recv_pkt() so socket lookup is separate from
>processing that occurs while holding the socket lock. This prepares the
>receive path to retain a looked-up socket across multiple packets in a
>later change.
>
>Keep virtio_transport_recv_pkt() on its existing per-packet locking path.
>Pass the caller-provided network namespace to the locked helper so reset
>handling retains its existing semantics. Preserve source validation and
>failure handling.
>
>Signed-off-by: Jia Jia <physicalmtea@gmail.com>
>---
> net/vmw_vsock/virtio_transport_common.c | 131 ++++++++++++++----------
> 1 file changed, 78 insertions(+), 53 deletions(-)
>
>diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c
>index f225f53ed4bab..43325d7aebbb1 100644
>--- a/net/vmw_vsock/virtio_transport_common.c
>+++ b/net/vmw_vsock/virtio_transport_common.c
>@@ -1774,6 +1774,80 @@ static bool virtio_transport_valid_type(u16 type)
> 	       (type == VIRTIO_VSOCK_TYPE_SEQPACKET);
> }
>
>+static struct sock *
>+virtio_transport_find_socket(struct sockaddr_vm *src,
>+			     struct sockaddr_vm *dst, struct net *net)
>+{
>+	struct sock *sk;
>+
>+	sk = vsock_find_connected_socket_net(src, dst, net);
>+	if (!sk)
>+		sk = vsock_find_bound_socket_net(dst, net);
>+
>+	return sk;
>+}
>+
>+/*
>+ * The caller holds sk's socket lock.
>+ */
>+static void
>+virtio_transport_recv_pkt_locked(struct virtio_transport *t,
>+				 struct sk_buff *skb, struct sock *sk,
>+				 struct net *net)
>+{
>+	struct virtio_vsock_hdr *hdr = virtio_vsock_hdr(skb);
>+	struct vsock_sock *vsk = vsock_sk(sk);
>+	struct sockaddr_vm src;
>+	bool space_available;
>+
>+	vsock_addr_init(&src, le64_to_cpu(hdr->src_cid),
>+			le32_to_cpu(hdr->src_port));
>+
>+	/*
>+	 * The socket may have been closed or reassigned after lookup but before
>+	 * its socket lock was acquired. Listener sockets have no assigned
>+	 * transport.
>+	 */
>+	if (sock_flag(sk, SOCK_DONE) ||
>+	    (sk->sk_state != TCP_LISTEN &&
>+	     !vsock_check_source(vsk, &t->transport, &src))) {
>+		(void)virtio_transport_reset_no_sock(t, skb, net);
>+		kfree_skb(skb);
>+		return;
>+	}
>+
>+	space_available = virtio_transport_space_update(sk, skb);
>+
>+	/* Update CID in case it has changed after a transport reset event */
>+	if (vsk->local_addr.svm_cid != VMADDR_CID_ANY)
>+		vsk->local_addr.svm_cid = le64_to_cpu(hdr->dst_cid);
>+
>+	if (space_available)
>+		sk->sk_write_space(sk);
>+
>+	switch (sk->sk_state) {
>+	case TCP_LISTEN:
>+		virtio_transport_recv_listen(sk, skb, t);
>+		kfree_skb(skb);
>+		break;
>+	case TCP_SYN_SENT:
>+		virtio_transport_recv_connecting(sk, skb);
>+		kfree_skb(skb);
>+		break;
>+	case TCP_ESTABLISHED:
>+		virtio_transport_recv_connected(sk, skb);
>+		break;
>+	case TCP_CLOSING:
>+		virtio_transport_recv_disconnecting(sk, skb);
>+		kfree_skb(skb);
>+		break;
>+	default:
>+		(void)virtio_transport_reset_no_sock(t, skb, net);
>+		kfree_skb(skb);
>+		break;
>+	}
>+}
>+
> /* We are under the virtio-vsock's vsock->rx_lock or vhost-vsock's vq->mutex
>  * lock.
>  */
>@@ -1782,9 +1856,7 @@ void virtio_transport_recv_pkt(struct virtio_transport *t,
> {
> 	struct virtio_vsock_hdr *hdr = virtio_vsock_hdr(skb);
> 	struct sockaddr_vm src, dst;
>-	struct vsock_sock *vsk;
> 	struct sock *sk;
>-	bool space_available;
>
> 	vsock_addr_init(&src, le64_to_cpu(hdr->src_cid),
> 			le32_to_cpu(hdr->src_port));
>@@ -1808,13 +1880,10 @@ void virtio_transport_recv_pkt(struct virtio_transport *t,
> 	/* The socket must be in connected or bound table
> 	 * otherwise send reset back
> 	 */
>-	sk = vsock_find_connected_socket_net(&src, &dst, net);
>+	sk = virtio_transport_find_socket(&src, &dst, net);
> 	if (!sk) {
>-		sk = vsock_find_bound_socket_net(&dst, net);
>-		if (!sk) {
>-			(void)virtio_transport_reset_no_sock(t, skb, net);
>-			goto free_pkt;
>-		}
>+		(void)virtio_transport_reset_no_sock(t, skb, net);
>+		goto free_pkt;
> 	}
>
> 	if (virtio_transport_get_type(sk) != le16_to_cpu(hdr->type)) {
>@@ -1828,52 +1897,8 @@ void virtio_transport_recv_pkt(struct virtio_transport *t,
> 		goto free_pkt;
> 	}
>
>-	vsk = vsock_sk(sk);
>-
> 	lock_sock(sk);
>-
>-	/* Check if sk has been closed or assigned to another transport before
>-	 * lock_sock (note: listener sockets are not assigned to any transport)
>-	 */
>-	if (sock_flag(sk, SOCK_DONE) ||
>-	    (sk->sk_state != TCP_LISTEN &&
>-	     !vsock_check_source(vsk, &t->transport, &src))) {
>-		(void)virtio_transport_reset_no_sock(t, skb, net);
>-		release_sock(sk);
>-		sock_put(sk);
>-		goto free_pkt;
>-	}
>-
>-	space_available = virtio_transport_space_update(sk, skb);
>-
>-	/* Update CID in case it has changed after a transport reset event */
>-	if (vsk->local_addr.svm_cid != VMADDR_CID_ANY)
>-		vsk->local_addr.svm_cid = dst.svm_cid;
>-
>-	if (space_available)
>-		sk->sk_write_space(sk);
>-
>-	switch (sk->sk_state) {
>-	case TCP_LISTEN:
>-		virtio_transport_recv_listen(sk, skb, t);
>-		kfree_skb(skb);
>-		break;
>-	case TCP_SYN_SENT:
>-		virtio_transport_recv_connecting(sk, skb);
>-		kfree_skb(skb);
>-		break;
>-	case TCP_ESTABLISHED:
>-		virtio_transport_recv_connected(sk, skb);
>-		break;
>-	case TCP_CLOSING:
>-		virtio_transport_recv_disconnecting(sk, skb);
>-		kfree_skb(skb);
>-		break;
>-	default:
>-		(void)virtio_transport_reset_no_sock(t, skb, net);
>-		kfree_skb(skb);
>-		break;
>-	}
>+	virtio_transport_recv_pkt_locked(t, skb, sk, net);
>

nit: if you need to resend, please remove this blank line or add a blank 
line after lock_sock().

The rest LGTM:

Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>


> 	release_sock(sk);
>
>-- 
>2.53.0
>