Re: [RFC PATCH v5 05/19] af_vsock: separate wait space loop

This moves loop that waits for space on send to separate function,
because it will be used for SEQ_BEGIN/SEQ_END sending before and
after data transmission. Waiting for SEQ_BEGIN/SEQ_END is needed
because such packets carries SEQPACKET header that couldn't be
fragmented by credit mechanism, so to avoid it, sender waits until
enough space will be ready.

Signed-off-by: Arseny Krasnov <redacted>
---
include/net/af_vsock.h   |  2 +
net/vmw_vsock/af_vsock.c | 99 +++++++++++++++++++++++++---------------
2 files changed, 63 insertions(+), 38 deletions(-)

diff --git a/include/net/af_vsock.h b/include/net/af_vsock.h
index 01563338cc03..6fbe88306403 100644
--- a/include/net/af_vsock.h
+++ b/include/net/af_vsock.h

@@ -205,6 +205,8 @@ void vsock_remove_sock(struct vsock_sock *vsk);

void vsock_for_each_connected_socket(void (*fn)(struct sock *sk));
int vsock_assign_transport(struct vsock_sock *vsk, struct vsock_sock *psk);
bool vsock_find_cid(unsigned int cid);
+int vsock_wait_space(struct sock *sk, size_t space, int flags,
+		     struct vsock_transport_send_notify_data *send_data);

/**** TAP ****/

diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
index b754927a556a..09b377422b1e 100644
--- a/net/vmw_vsock/af_vsock.c
+++ b/net/vmw_vsock/af_vsock.c

@@ -1692,6 +1692,65 @@ static int vsock_connectible_getsockopt(struct socket *sock,

	return 0;
}

+int vsock_wait_space(struct sock *sk, size_t space, int flags,
+		     struct vsock_transport_send_notify_data *send_data)
+{
+	const struct vsock_transport *transport;
+	struct vsock_sock *vsk;
+	long timeout;
+	int err;
+
+	DEFINE_WAIT_FUNC(wait, woken_wake_function);
+
+	vsk = vsock_sk(sk);
+	transport = vsk->transport;
+	timeout = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
+	err = 0;
+
+	add_wait_queue(sk_sleep(sk), &wait);
+
+	while (vsock_stream_has_space(vsk) < space &&
+	       sk->sk_err == 0 &&
+	       !(sk->sk_shutdown & SEND_SHUTDOWN) &&
+	       !(vsk->peer_shutdown & RCV_SHUTDOWN)) {
+
+		/* Don't wait for non-blocking sockets. */
+		if (timeout == 0) {
+			err = -EAGAIN;
+			goto out_err;
+		}
+
+		if (send_data) {
+			err = transport->notify_send_pre_block(vsk, send_data);
+			if (err < 0)
+				goto out_err;
+		}
+
+		release_sock(sk);
+		timeout = wait_woken(&wait, TASK_INTERRUPTIBLE, timeout);
+		lock_sock(sk);
+		if (signal_pending(current)) {
+			err = sock_intr_errno(timeout);
+			goto out_err;
+		} else if (timeout == 0) {
+			err = -EAGAIN;
+			goto out_err;
+		}
+	}
+
+	if (sk->sk_err) {
+		err = -sk->sk_err;
+	} else if ((sk->sk_shutdown & SEND_SHUTDOWN) ||
+		   (vsk->peer_shutdown & RCV_SHUTDOWN)) {
+		err = -EPIPE;
+	}
+
+out_err:
+	remove_wait_queue(sk_sleep(sk), &wait);
+	return err;
+}
+EXPORT_SYMBOL_GPL(vsock_wait_space);
+
static int vsock_connectible_sendmsg(struct socket *sock, struct msghdr *msg,
				     size_t len)
{

@@ -1699,10 +1758,8 @@ static int vsock_connectible_sendmsg(struct socket *sock, struct msghdr *msg,

	struct vsock_sock *vsk;
	const struct vsock_transport *transport;
	ssize_t total_written;
-	long timeout;
	int err;
	struct vsock_transport_send_notify_data send_data;
-	DEFINE_WAIT_FUNC(wait, woken_wake_function);

	sk = sock->sk;
	vsk = vsock_sk(sk);

@@ -1740,9 +1797,6 @@ static int vsock_connectible_sendmsg(struct socket *sock, struct msghdr *msg,

		goto out;
	}

-	/* Wait for room in the produce queue to enqueue our user's data. */
-	timeout = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
-
	err = transport->notify_send_init(vsk, &send_data);
	if (err < 0)
		goto out;

@@ -1750,39 +1804,8 @@ static int vsock_connectible_sendmsg(struct socket *sock, struct msghdr *msg,

	while (total_written < len) {
		ssize_t written;

-		add_wait_queue(sk_sleep(sk), &wait);
-		while (vsock_stream_has_space(vsk) == 0 &&
-		       sk->sk_err == 0 &&
-		       !(sk->sk_shutdown & SEND_SHUTDOWN) &&
-		       !(vsk->peer_shutdown & RCV_SHUTDOWN)) {
-
-			/* Don't wait for non-blocking sockets. */
-			if (timeout == 0) {
-				err = -EAGAIN;
-				remove_wait_queue(sk_sleep(sk), &wait);
-				goto out_err;
-			}
-
-			err = transport->notify_send_pre_block(vsk, &send_data);
-			if (err < 0) {
-				remove_wait_queue(sk_sleep(sk), &wait);
-				goto out_err;
-			}
-
-			release_sock(sk);
-			timeout = wait_woken(&wait, TASK_INTERRUPTIBLE, timeout);
-			lock_sock(sk);
-			if (signal_pending(current)) {
-				err = sock_intr_errno(timeout);
-				remove_wait_queue(sk_sleep(sk), &wait);
-				goto out_err;
-			} else if (timeout == 0) {
-				err = -EAGAIN;
-				remove_wait_queue(sk_sleep(sk), &wait);
-				goto out_err;
-			}
-		}
-		remove_wait_queue(sk_sleep(sk), &wait);
+		if (vsock_wait_space(sk, 1, msg->msg_flags, &send_data))
+			goto out_err;

		/* These checks occur both as part of and after the loop
		 * conditional since we need to check before and after
-- 
2.25.1