Re: [RFC PATCH v5 02/19] af_vsock: separate wait data loop

[Stefano Garzarella <sgarzare@redhat.com>]

On Thu, Feb 18, 2021 at 08:36:33AM +0300, Arseny Krasnov wrote:
>This moves wait loop for data to dedicated function, because later
>it will be used by SEQPACKET data receive loop.

The patch LGTM, maybe just add a line in the commit message with 
something like this:

     While moving the code around, let's update an old comment.

Whit that fixed:

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

>
>Signed-off-by: Arseny Krasnov <arseny.krasnov@kaspersky.com>
>---
> net/vmw_vsock/af_vsock.c | 155 +++++++++++++++++++++------------------
> 1 file changed, 83 insertions(+), 72 deletions(-)
>
>diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
>index 656370e11707..6cf7bb977aa1 100644
>--- a/net/vmw_vsock/af_vsock.c
>+++ b/net/vmw_vsock/af_vsock.c
>@@ -1832,6 +1832,68 @@ static int vsock_connectible_sendmsg(struct socket *sock, struct msghdr *msg,
> 	return err;
> }
>
>+static int vsock_wait_data(struct sock *sk, struct wait_queue_entry *wait,
>+			   long timeout,
>+			   struct vsock_transport_recv_notify_data *recv_data,
>+			   size_t target)
>+{
>+	const struct vsock_transport *transport;
>+	struct vsock_sock *vsk;
>+	s64 data;
>+	int err;
>+
>+	vsk = vsock_sk(sk);
>+	err = 0;
>+	transport = vsk->transport;
>+	prepare_to_wait(sk_sleep(sk), wait, TASK_INTERRUPTIBLE);
>+
>+	while ((data = vsock_stream_has_data(vsk)) == 0) {
>+		if (sk->sk_err != 0 ||
>+		    (sk->sk_shutdown & RCV_SHUTDOWN) ||
>+		    (vsk->peer_shutdown & SEND_SHUTDOWN)) {
>+			break;
>+		}
>+
>+		/* Don't wait for non-blocking sockets. */
>+		if (timeout == 0) {
>+			err = -EAGAIN;
>+			break;
>+		}
>+
>+		if (recv_data) {
>+			err = transport->notify_recv_pre_block(vsk, target, recv_data);
>+			if (err < 0)
>+				break;
>+		}
>+
>+		release_sock(sk);
>+		timeout = schedule_timeout(timeout);
>+		lock_sock(sk);
>+
>+		if (signal_pending(current)) {
>+			err = sock_intr_errno(timeout);
>+			break;
>+		} else if (timeout == 0) {
>+			err = -EAGAIN;
>+			break;
>+		}
>+	}
>+
>+	finish_wait(sk_sleep(sk), wait);
>+
>+	if (err)
>+		return err;
>+
>+	/* Internal transport error when checking for available
>+	 * data. XXX This should be changed to a connection
>+	 * reset in a later change.
>+	 */
>+	if (data < 0)
>+		return -ENOMEM;
>+
>+	return data;
>+}
>+
> static int
> vsock_connectible_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
> 			  int flags)
>@@ -1911,85 +1973,34 @@ vsock_connectible_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
>
>
> 	while (1) {
>-		s64 ready;
>-
>-		prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
>-		ready = vsock_stream_has_data(vsk);
>-
>-		if (ready == 0) {
>-			if (sk->sk_err != 0 ||
>-			    (sk->sk_shutdown & RCV_SHUTDOWN) ||
>-			    (vsk->peer_shutdown & SEND_SHUTDOWN)) {
>-				finish_wait(sk_sleep(sk), &wait);
>-				break;
>-			}
>-			/* Don't wait for non-blocking sockets. */
>-			if (timeout == 0) {
>-				err = -EAGAIN;
>-				finish_wait(sk_sleep(sk), &wait);
>-				break;
>-			}
>+		ssize_t read;
>
>-			err = transport->notify_recv_pre_block(
>-					vsk, target, &recv_data);
>-			if (err < 0) {
>-				finish_wait(sk_sleep(sk), &wait);
>-				break;
>-			}
>-			release_sock(sk);
>-			timeout = schedule_timeout(timeout);
>-			lock_sock(sk);
>+		err = vsock_wait_data(sk, &wait, timeout, &recv_data, target);
>+		if (err <= 0)
>+			break;
>
>-			if (signal_pending(current)) {
>-				err = sock_intr_errno(timeout);
>-				finish_wait(sk_sleep(sk), &wait);
>-				break;
>-			} else if (timeout == 0) {
>-				err = -EAGAIN;
>-				finish_wait(sk_sleep(sk), &wait);
>-				break;
>-			}
>-		} else {
>-			ssize_t read;
>-
>-			finish_wait(sk_sleep(sk), &wait);
>-
>-			if (ready < 0) {
>-				/* Invalid queue pair content. XXX This should
>-				* be changed to a connection reset in a later
>-				* change.
>-				*/
>-
>-				err = -ENOMEM;
>-				goto out;
>-			}
>-
>-			err = transport->notify_recv_pre_dequeue(
>-					vsk, target, &recv_data);
>-			if (err < 0)
>-				break;
>+		err = transport->notify_recv_pre_dequeue(vsk, target,
>+							 &recv_data);
>+		if (err < 0)
>+			break;
>
>-			read = transport->stream_dequeue(
>-					vsk, msg,
>-					len - copied, flags);
>-			if (read < 0) {
>-				err = -ENOMEM;
>-				break;
>-			}
>+		read = transport->stream_dequeue(vsk, msg, len - copied, flags);
>+		if (read < 0) {
>+			err = -ENOMEM;
>+			break;
>+		}
>
>-			copied += read;
>+		copied += read;
>
>-			err = transport->notify_recv_post_dequeue(
>-					vsk, target, read,
>-					!(flags & MSG_PEEK), &recv_data);
>-			if (err < 0)
>-				goto out;
>+		err = transport->notify_recv_post_dequeue(vsk, target, read,
>+						!(flags & MSG_PEEK), &recv_data);
>+		if (err < 0)
>+			goto out;
>
>-			if (read >= target || flags & MSG_PEEK)
>-				break;
>+		if (read >= target || flags & MSG_PEEK)
>+			break;
>
>-			target -= read;
>-		}
>+		target -= read;
> 	}
>
> 	if (sk->sk_err)
>-- 
>2.25.1
>