-----Original Message-----
From: Ying Xue [mailto:ying.xue@windriver.com]
Sent: February-27-15 6:07 AM
To: viro@ZenIV.linux.org.uk; hch@lst.de; davem@davemloft.net
Cc: netdev@vger.kernel.org; Erik Hugne; Jon Maloy
Subject: [PATCH net-next 1/2] tipc: Don't use iocb argument in socket layer

Currently the iocb argument is used to idenfiy whether or not socket lock is
hold before tipc_sendmsg()/tipc_send_stream() is called. But this usage
prevents iocb argument from being dropped through sendmsg() at socket
common layer. Therefore, in the commit we introduce two new functions
called __tipc_sendmsg() and __tipc_send_stream(). When they are invoked,
it assumes that their callers have taken socket lock, thereby avoiding the
weird usage of iocb argument.

Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>
Reviewed-by: Erik Hugne <redacted>
Signed-off-by: Ying Xue <redacted>
---
 net/tipc/socket.c |   82 ++++++++++++++++++++++++++++--------------------
-----
 1 file changed, 44 insertions(+), 38 deletions(-)

diff --git a/net/tipc/socket.c b/net/tipc/socket.c index f73e975..c245ec3

100644

--- a/net/tipc/socket.c
+++ b/net/tipc/socket.c

@@ -114,6 +114,9 @@ static int tipc_sk_withdraw(struct tipc_sock *tsk, uint

scope,  static struct tipc_sock *tipc_sk_lookup(struct net *net, u32 portid);
static int tipc_sk_insert(struct tipc_sock *tsk);  static void
tipc_sk_remove(struct tipc_sock *tsk);
+static int __tipc_send_stream(struct socket *sock, struct msghdr *m,
+			      size_t dsz);
+static int __tipc_sendmsg(struct socket *sock, struct msghdr *m, size_t
+dsz);

 static const struct proto_ops packet_ops;  static const struct proto_ops
stream_ops; @@ -907,6 +910,18 @@ static int tipc_wait_for_sndmsg(struct
socket *sock, long *timeo_p)  static int tipc_sendmsg(struct kiocb *iocb,
struct socket *sock,
 			struct msghdr *m, size_t dsz)
 {
+	struct sock *sk = sock->sk;
+	int ret;

+	release_sock(sk);
+
+	return ret;
+}
+
+static int __tipc_sendmsg(struct socket *sock, struct msghdr *m, size_t
+dsz) {
 	DECLARE_SOCKADDR(struct sockaddr_tipc *, dest, m->msg_name);
 	struct sock *sk = sock->sk;
 	struct tipc_sock *tsk = tipc_sk(sk);

@@ -931,22 +946,13 @@ static int tipc_sendmsg(struct kiocb *iocb, struct

socket *sock,
 	if (dsz > TIPC_MAX_USER_MSG_SIZE)
 		return -EMSGSIZE;

-	if (iocb)
-		lock_sock(sk);
-
 	if (unlikely(sock->state != SS_READY)) {
-		if (sock->state == SS_LISTENING) {
-			rc = -EPIPE;
-			goto exit;
-		}
-		if (sock->state != SS_UNCONNECTED) {
-			rc = -EISCONN;
-			goto exit;
-		}
-		if (tsk->published) {
-			rc = -EOPNOTSUPP;
-			goto exit;
-		}
+		if (sock->state == SS_LISTENING)
+			return -EPIPE;
+		if (sock->state != SS_UNCONNECTED)
+			return -EISCONN;
+		if (tsk->published)
+			return -EOPNOTSUPP;
 		if (dest->addrtype == TIPC_ADDR_NAME) {
 			tsk->conn_type = dest->addr.name.name.type;
 			tsk->conn_instance = dest-

quoted

addr.name.name.instance; @@ -956,8 +962,7 @@ static int

tipc_sendmsg(struct kiocb *iocb, struct socket *sock,
 	timeo = sock_sndtimeo(sk, m->msg_flags & MSG_DONTWAIT);

 	if (dest->addrtype == TIPC_ADDR_MCAST) {
-		rc = tipc_sendmcast(sock, seq, m, dsz, timeo);
-		goto exit;
+		return tipc_sendmcast(sock, seq, m, dsz, timeo);
 	} else if (dest->addrtype == TIPC_ADDR_NAME) {
 		u32 type = dest->addr.name.name.type;
 		u32 inst = dest->addr.name.name.instance; @@ -972,10
+977,8 @@ static int tipc_sendmsg(struct kiocb *iocb, struct socket *sock,
 		dport = tipc_nametbl_translate(net, type, inst, &dnode);
 		msg_set_destnode(mhdr, dnode);
 		msg_set_destport(mhdr, dport);
-		if (unlikely(!dport && !dnode)) {
-			rc = -EHOSTUNREACH;
-			goto exit;
-		}
+		if (unlikely(!dport && !dnode))
+			return -EHOSTUNREACH;
 	} else if (dest->addrtype == TIPC_ADDR_ID) {
 		dnode = dest->addr.id.node;
 		msg_set_type(mhdr, TIPC_DIRECT_MSG);

@@ -990,7 +993,7 @@ new_mtu:
 	mtu = tipc_node_get_mtu(net, dnode, tsk->portid);
 	rc = tipc_msg_build(mhdr, m, 0, dsz, mtu, pktchain);
 	if (rc < 0)
-		goto exit;
+		return rc;

 	do {
 		skb = skb_peek(pktchain);

@@ -1013,9 +1016,6 @@ new_mtu:
 		if (rc)
 			__skb_queue_purge(pktchain);
 	} while (!rc);
-exit:
-	if (iocb)
-		release_sock(sk);

 	return rc;
 }

@@ -1066,6 +1066,18 @@ static int tipc_send_stream(struct kiocb *iocb,

struct socket *sock,
 			    struct msghdr *m, size_t dsz)
 {
 	struct sock *sk = sock->sk;
+	int ret;
+
+	lock_sock(sk);
+	ret = __tipc_send_stream(sock, m, dsz);
+	release_sock(sk);
+
+	return ret;
+}
+
+static int __tipc_send_stream(struct socket *sock, struct msghdr *m,
+size_t dsz) {
+	struct sock *sk = sock->sk;
 	struct net *net = sock_net(sk);
 	struct tipc_sock *tsk = tipc_sk(sk);
 	struct tipc_msg *mhdr = &tsk->phdr;

@@ -1080,7 +1092,7 @@ static int tipc_send_stream(struct kiocb *iocb,

struct socket *sock,

 	/* Handle implied connection establishment */
 	if (unlikely(dest)) {
-		rc = tipc_sendmsg(iocb, sock, m, dsz);
+		rc = __tipc_sendmsg(sock, m, dsz);
 		if (dsz && (dsz == rc))
 			tsk->sent_unacked = 1;
 		return rc;

@@ -1088,15 +1100,11 @@ static int tipc_send_stream(struct kiocb *iocb,

struct socket *sock,
 	if (dsz > (uint)INT_MAX)
 		return -EMSGSIZE;

-	if (iocb)
-		lock_sock(sk);
-
 	if (unlikely(sock->state != SS_CONNECTED)) {
 		if (sock->state == SS_DISCONNECTING)
-			rc = -EPIPE;
+			return -EPIPE;
 		else
-			rc = -ENOTCONN;
-		goto exit;
+			return -ENOTCONN;
 	}

 	timeo = sock_sndtimeo(sk, m->msg_flags & MSG_DONTWAIT); @@
-1108,7 +1116,7 @@ next:
 	send = min_t(uint, dsz - sent, TIPC_MAX_USER_MSG_SIZE);
 	rc = tipc_msg_build(mhdr, m, sent, send, mtu, pktchain);
 	if (unlikely(rc < 0))
-		goto exit;
+		return rc;
 	do {
 		if (likely(!tsk_conn_cong(tsk))) {
 			rc = tipc_link_xmit(net, pktchain, dnode, portid); @@
-1133,9 +1141,7 @@ next:
 		if (rc)
 			__skb_queue_purge(pktchain);
 	} while (!rc);
-exit:
-	if (iocb)
-		release_sock(sk);
+
 	return sent ? sent : rc;
 }

@@ -1947,7 +1953,7 @@ static int tipc_connect(struct socket *sock, struct

sockaddr *dest,
 		if (!timeout)
 			m.msg_flags = MSG_DONTWAIT;

-		res = tipc_sendmsg(NULL, sock, &m, 0);
+		res = __tipc_sendmsg(sock, &m, 0);
 		if ((res < 0) && (res != -EWOULDBLOCK))
 			goto exit;

@@ -2103,7 +2109,7 @@ static int tipc_accept(struct socket *sock, struct

socket *new_sock, int flags)
 		struct msghdr m = {NULL,};

 		tsk_advance_rx_queue(sk);
-		tipc_send_packet(NULL, new_sock, &m, 0);
+		__tipc_send_stream(new_sock, &m, 0);
 	} else {
 		__skb_dequeue(&sk->sk_receive_queue);
 		__skb_queue_head(&new_sk->sk_receive_queue, buf);
--
1.7.9.5