sctp: adjust some codes in a better order in sctp_sendmsg

sctp_sendmsg_new_asoc and SCTP_ADDR_OVER check is only necessary
when daddr is set, so move them up to if (daddr) statement.
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/sctp/socket.c

@@ -1936,26 +1936,15 @@ static int sctp_sendmsg(struct sock *sk, struct msghdr *msg, size_t msg_len)
 
 	lock_sock(sk);
 
-	/* If a msg_name has been specified, assume this is to be used.  */
+	/* Get and check or create asoc */
 	if (daddr) {
-		/* Look for a matching association on the endpoint. */
 		asoc = sctp_endpoint_lookup_assoc(ep, daddr, &transport);
-	} else {
-		asoc = sctp_id2assoc(sk, sinfo->sinfo_assoc_id);
-		if (!asoc) {
-			err = -EPIPE;
-			goto out_unlock;
-		}
-	}
-
 		if (asoc) {
-		err = sctp_sendmsg_check_sflags(asoc, sflags, msg, msg_len);
+			err = sctp_sendmsg_check_sflags(asoc, sflags, msg,
+							msg_len);
 			if (err <= 0)
 				goto out_unlock;
-	}
-
-	/* Do we need to create the association?  */
-	if (!asoc) {
+		} else {
 			err = sctp_sendmsg_new_asoc(sk, sflags, &cmsgs, daddr,
 						    &transport);
 			if (err)
@@ -1967,6 +1956,17 @@ static int sctp_sendmsg(struct sock *sk, struct msghdr *msg, size_t msg_len)
 
 		if (!sctp_style(sk, TCP) && !(sflags & SCTP_ADDR_OVER))
 			transport = NULL;
+	} else {
+		asoc = sctp_id2assoc(sk, sinfo->sinfo_assoc_id);
+		if (!asoc) {
+			err = -EPIPE;
+			goto out_unlock;
+		}
+
+		err = sctp_sendmsg_check_sflags(asoc, sflags, msg, msg_len);
+		if (err <= 0)
+			goto out_unlock;
+	}
 
 	/* Update snd_info with the asoc */
 	sctp_sendmsg_update_sinfo(asoc, sinfo, &cmsgs);