mptcp: fix bogus sendmsg() return code under pressure

In case of memory pressure, mptcp_sendmsg() may call sk_stream_wait_memory() after succesfully xmitting some bytes. If the latter fails we currently return to the user-space the error code, ignoring the succeful xmit. Address the issue always checking for the xmitted bytes before mptcp_sendmsg() completes. Fixes: f296234 ("mptcp: Add handling of incoming MP_JOIN requests") Reviewed-by: Matthieu Baerts <[email protected]> Signed-off-by: Paolo Abeni <[email protected]> Signed-off-by: David S. Miller <[email protected]>
devinus · Aug 4, 2020 · 8555c6b · 8555c6b
1 parent f8deaea
commit 8555c6b
Showing 1 changed file with 1 addition and 2 deletions.
diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
@@ -984,7 +984,6 @@ static int mptcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 
 	mptcp_set_timeout(sk, ssk);
 	if (copied) {
-		ret = copied;
 		tcp_push(ssk, msg->msg_flags, mss_now, tcp_sk(ssk)->nonagle,
 			 size_goal);
 
@@ -997,7 +996,7 @@ static int mptcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 	release_sock(ssk);
 out:
 	release_sock(sk);
-	return ret;
+	return copied ? : ret;
 }
 
 static void mptcp_wait_data(struct sock *sk, long *timeo)