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From:   Arseny Krasnov <arseny.krasnov@kaspersky.com>
To:     Stefan Hajnoczi <stefanha@redhat.com>,
        Stefano Garzarella <sgarzare@redhat.com>,
        "Michael S. Tsirkin" <mst@redhat.com>,
        Jason Wang <jasowang@redhat.com>,
        "David S. Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>,
        Arseny Krasnov <arseny.krasnov@kaspersky.com>,
        Jorgen Hansen <jhansen@vmware.com>,
        Andra Paraschiv <andraprs@amazon.com>,
        Colin Ian King <colin.king@canonical.com>,
        Jeff Vander Stoep <jeffv@google.com>
CC:     <kvm@vger.kernel.org>, <virtualization@lists.linux-foundation.org>,
        <netdev@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
        <stsp2@yandex.ru>, <oxffffaa@gmail.com>
Subject: [RFC PATCH v2 04/13] af_vsock: replace previous stream rx loop.
Date:   Fri, 15 Jan 2021 08:41:38 +0300
Message-ID: <20210115054141.1456019-1-arseny.krasnov@kaspersky.com>
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This removes previous 'vsock_stream_recvmsg()' and uses newly implemented
receive loops. Moved to separate patch to make review easier.

Signed-off-by: Arseny Krasnov <arseny.krasnov@kaspersky.com>
---
 net/vmw_vsock/af_vsock.c | 184 +++------------------------------------
 1 file changed, 12 insertions(+), 172 deletions(-)

diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
index 38afaa90d141..5bf887190881 100644
--- a/net/vmw_vsock/af_vsock.c
+++ b/net/vmw_vsock/af_vsock.c
@@ -2072,178 +2072,6 @@ static int __vsock_stream_recvmsg(struct sock *sk, struct msghdr *msg,
 	return err;
 }
 
-static int
-vsock_stream_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
-		     int flags)
-{
-	struct sock *sk;
-	struct vsock_sock *vsk;
-	const struct vsock_transport *transport;
-	int err;
-	size_t target;
-	ssize_t copied;
-	long timeout;
-	struct vsock_transport_recv_notify_data recv_data;
-
-	DEFINE_WAIT(wait);
-
-	sk = sock->sk;
-	vsk = vsock_sk(sk);
-	transport = vsk->transport;
-	err = 0;
-
-	lock_sock(sk);
-
-	if (!transport || sk->sk_state != TCP_ESTABLISHED) {
-		/* Recvmsg is supposed to return 0 if a peer performs an
-		 * orderly shutdown. Differentiate between that case and when a
-		 * peer has not connected or a local shutdown occured with the
-		 * SOCK_DONE flag.
-		 */
-		if (sock_flag(sk, SOCK_DONE))
-			err = 0;
-		else
-			err = -ENOTCONN;
-
-		goto out;
-	}
-
-	if (flags & MSG_OOB) {
-		err = -EOPNOTSUPP;
-		goto out;
-	}
-
-	/* We don't check peer_shutdown flag here since peer may actually shut
-	 * down, but there can be data in the queue that a local socket can
-	 * receive.
-	 */
-	if (sk->sk_shutdown & RCV_SHUTDOWN) {
-		err = 0;
-		goto out;
-	}
-
-	/* It is valid on Linux to pass in a zero-length receive buffer.  This
-	 * is not an error.  We may as well bail out now.
-	 */
-	if (!len) {
-		err = 0;
-		goto out;
-	}
-
-	/* We must not copy less than target bytes into the user's buffer
-	 * before returning successfully, so we wait for the consume queue to
-	 * have that much data to consume before dequeueing.  Note that this
-	 * makes it impossible to handle cases where target is greater than the
-	 * queue size.
-	 */
-	target = sock_rcvlowat(sk, flags & MSG_WAITALL, len);
-	if (target >= transport->stream_rcvhiwat(vsk)) {
-		err = -ENOMEM;
-		goto out;
-	}
-	timeout = sock_rcvtimeo(sk, flags & MSG_DONTWAIT);
-	copied = 0;
-
-	err = transport->notify_recv_init(vsk, target, &recv_data);
-	if (err < 0)
-		goto out;
-
-
-	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;
-			}
-
-			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);
-
-			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;
-
-			read = transport->stream_dequeue(
-					vsk, msg,
-					len - copied, flags);
-			if (read < 0) {
-				err = -ENOMEM;
-				break;
-			}
-
-			copied += read;
-
-			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;
-
-			target -= read;
-		}
-	}
-
-	if (sk->sk_err)
-		err = -sk->sk_err;
-	else if (sk->sk_shutdown & RCV_SHUTDOWN)
-		err = 0;
-
-	if (copied > 0)
-		err = copied;
-
-out:
-	release_sock(sk);
-	return err;
-}
-
 static int vsock_connectible_recvmsg(struct socket *sock, struct msghdr *msg,
 				     size_t len, int flags)
 {
@@ -2299,6 +2127,18 @@ static int vsock_connectible_recvmsg(struct socket *sock, struct msghdr *msg,
 	return err;
 }
 
+static int vsock_seqpacket_recvmsg(struct socket *sock, struct msghdr *msg,
+				   size_t len, int flags)
+{
+	return vsock_connectible_recvmsg(sock, msg, len, flags);
+}
+
+static int vsock_stream_recvmsg(struct socket *sock, struct msghdr *msg,
+				size_t len, int flags)
+{
+	return vsock_connectible_recvmsg(sock, msg, len, flags);
+}
+
 static const struct proto_ops vsock_stream_ops = {
 	.family = PF_VSOCK,
 	.owner = THIS_MODULE,
-- 
2.25.1