mptcp: move __mptcp_error_report in protocol.c

This will simplify the next patch ("mptcp: process pending subflow error
on close").

No functional change intended.

Cc: stable@vger.kernel.org # v5.12+
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

Author: Paolo Abeni

net/mptcp/protocol.c

@@ -770,6 +770,42 @@ static bool __mptcp_ofo_queue(struct mptcp_sock *msk)
 	return moved;
 }
 
+void __mptcp_error_report(struct sock *sk)
+{
+	struct mptcp_subflow_context *subflow;
+	struct mptcp_sock *msk = mptcp_sk(sk);
+
+	mptcp_for_each_subflow(msk, subflow) {
+		struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
+		int err = sock_error(ssk);
+		int ssk_state;
+
+		if (!err)
+			continue;
+
+		/* only propagate errors on fallen-back sockets or
+		 * on MPC connect
+		 */
+		if (sk->sk_state != TCP_SYN_SENT && !__mptcp_check_fallback(msk))
+			continue;
+
+		/* We need to propagate only transition to CLOSE state.
+		 * Orphaned socket will see such state change via
+		 * subflow_sched_work_if_closed() and that path will properly
+		 * destroy the msk as needed.
+		 */
+		ssk_state = inet_sk_state_load(ssk);
+		if (ssk_state == TCP_CLOSE && !sock_flag(sk, SOCK_DEAD))
+			inet_sk_state_store(sk, ssk_state);
+		WRITE_ONCE(sk->sk_err, -err);
+
+		/* This barrier is coupled with smp_rmb() in mptcp_poll() */
+		smp_wmb();
+		sk_error_report(sk);
+		break;
+	}
+}
+
 /* In most cases we will be able to lock the mptcp socket.  If its already
  * owned, we need to defer to the work queue to avoid ABBA deadlock.
  */

net/mptcp/subflow.c

@@ -1362,42 +1362,6 @@ void mptcp_space(const struct sock *ssk, int *space, int *full_space)
 	*full_space = mptcp_win_from_space(sk, READ_ONCE(sk->sk_rcvbuf));
 }
 
-void __mptcp_error_report(struct sock *sk)
-{
-	struct mptcp_subflow_context *subflow;
-	struct mptcp_sock *msk = mptcp_sk(sk);
-
-	mptcp_for_each_subflow(msk, subflow) {
-		struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
-		int err = sock_error(ssk);
-		int ssk_state;
-
-		if (!err)
-			continue;
-
-		/* only propagate errors on fallen-back sockets or
-		 * on MPC connect
-		 */
-		if (sk->sk_state != TCP_SYN_SENT && !__mptcp_check_fallback(msk))
-			continue;
-
-		/* We need to propagate only transition to CLOSE state.
-		 * Orphaned socket will see such state change via
-		 * subflow_sched_work_if_closed() and that path will properly
-		 * destroy the msk as needed.
-		 */
-		ssk_state = inet_sk_state_load(ssk);
-		if (ssk_state == TCP_CLOSE && !sock_flag(sk, SOCK_DEAD))
-			inet_sk_state_store(sk, ssk_state);
-		WRITE_ONCE(sk->sk_err, -err);
-
-		/* This barrier is coupled with smp_rmb() in mptcp_poll() */
-		smp_wmb();
-		sk_error_report(sk);
-		break;
-	}
-}
-
 static void subflow_error_report(struct sock *ssk)
 {
 	struct sock *sk = mptcp_subflow_ctx(ssk)->conn;