linux-kernel - [RFC PATCH v4 03/17] af_vsock: separate receive data loop

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Message-ID: <20210207151508.804615-1-arseny.krasnov@kaspersky.com>
Date:   Sun, 7 Feb 2021 18:15:05 +0300
From:   Arseny Krasnov <arseny.krasnov@...persky.com>
To:     Stefan Hajnoczi <stefanha@...hat.com>,
        Stefano Garzarella <sgarzare@...hat.com>,
        "Michael S. Tsirkin" <mst@...hat.com>,
        Jason Wang <jasowang@...hat.com>,
        "David S. Miller" <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>,
        Arseny Krasnov <arseny.krasnov@...persky.com>,
        Jorgen Hansen <jhansen@...are.com>,
        Colin Ian King <colin.king@...onical.com>,
        Andra Paraschiv <andraprs@...zon.com>,
        Jeff Vander Stoep <jeffv@...gle.com>
CC:     <kvm@...r.kernel.org>, <virtualization@...ts.linux-foundation.org>,
        <netdev@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <stsp2@...dex.ru>, <oxffffaa@...il.com>
Subject: [RFC PATCH v4 03/17] af_vsock: separate receive data loop

This moves STREAM specific data receive logic to dedicated function:
'__vsock_stream_recvmsg()', while checks that will be same for both
types of socket are in shared function: 'vsock_connectible_recvmsg()'.

Signed-off-by: Arseny Krasnov <arseny.krasnov@...persky.com>
---
 net/vmw_vsock/af_vsock.c | 117 +++++++++++++++++++++++----------------
 1 file changed, 68 insertions(+), 49 deletions(-)

diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
index 38927695786f..66c8a932f49b 100644
--- a/net/vmw_vsock/af_vsock.c
+++ b/net/vmw_vsock/af_vsock.c
@@ -1898,65 +1898,22 @@ static int vsock_wait_data(struct sock *sk, struct wait_queue_entry *wait,
 	return err;
 }
 
-static int
-vsock_connectible_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
-			  int flags)
+static int __vsock_stream_recvmsg(struct sock *sk, struct msghdr *msg,
+				  size_t len, int flags)
 {
-	struct sock *sk;
-	struct vsock_sock *vsk;
+	struct vsock_transport_recv_notify_data recv_data;
 	const struct vsock_transport *transport;
-	int err;
-	size_t target;
+	struct vsock_sock *vsk;
 	ssize_t copied;
+	size_t target;
 	long timeout;
-	struct vsock_transport_recv_notify_data recv_data;
+	int err;
 
 	DEFINE_WAIT(wait);
 
-	sk = sock->sk;
 	vsk = vsock_sk(sk);
-	err = 0;
-
-	lock_sock(sk);
-
 	transport = vsk->transport;
 
-	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
@@ -2020,6 +1977,68 @@ vsock_connectible_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
 	return err;
 }
 
+static int
+vsock_connectible_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;
+
+	DEFINE_WAIT(wait);
+
+	sk = sock->sk;
+	vsk = vsock_sk(sk);
+	err = 0;
+
+	lock_sock(sk);
+
+	transport = vsk->transport;
+
+	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 occurred 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;
+	}
+
+	err = __vsock_stream_recvmsg(sk, msg, len, flags);
+
+out:
+	release_sock(sk);
+	return err;
+}
+
 static const struct proto_ops vsock_stream_ops = {
 	.family = PF_VSOCK,
 	.owner = THIS_MODULE,
-- 
2.25.1