mptcp: factor out __mptcp_retrans helper()

Will simplify the following patch, no functional change
intended.

Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

net/mptcp/protocol.c

@@ -2255,59 +2255,23 @@ static void mptcp_check_fastclose(struct mptcp_sock *msk)
 	mptcp_close_wake_up(sk);
 }
 
-static void mptcp_worker(struct work_struct *work)
+static void __mptcp_retrans(struct sock *sk)
 {
-	struct mptcp_sock *msk = container_of(work, struct mptcp_sock, work);
-	struct sock *ssk, *sk = &msk->sk.icsk_inet.sk;
+	struct mptcp_sock *msk = mptcp_sk(sk);
 	struct mptcp_sendmsg_info info = {};
 	struct mptcp_data_frag *dfrag;
 	size_t copied = 0;
-	int state, ret;
-
-	lock_sock(sk);
-	state = sk->sk_state;
-	if (unlikely(state == TCP_CLOSE))
-		goto unlock;
-
-	mptcp_check_data_fin_ack(sk);
-	__mptcp_flush_join_list(msk);
-
-	mptcp_check_fastclose(msk);
-
-	if (msk->pm.status)
-		mptcp_pm_nl_work(msk);
-
-	if (test_and_clear_bit(MPTCP_WORK_EOF, &msk->flags))
-		mptcp_check_for_eof(msk);
-
-	__mptcp_check_send_data_fin(sk);
-	mptcp_check_data_fin(sk);
-
-	/* There is no point in keeping around an orphaned sk timedout or
-	 * closed, but we need the msk around to reply to incoming DATA_FIN,
-	 * even if it is orphaned and in FIN_WAIT2 state
-	 */
-	if (sock_flag(sk, SOCK_DEAD) &&
-	    (mptcp_check_close_timeout(sk) || sk->sk_state == TCP_CLOSE)) {
-		inet_sk_state_store(sk, TCP_CLOSE);
-		__mptcp_destroy_sock(sk);
-		goto unlock;
-	}
-
-	if (test_and_clear_bit(MPTCP_WORK_CLOSE_SUBFLOW, &msk->flags))
-		__mptcp_close_subflow(msk);
-
-	if (!test_and_clear_bit(MPTCP_WORK_RTX, &msk->flags))
-		goto unlock;
+	struct sock *ssk;
+	int ret;
 
 	__mptcp_clean_una(sk);
 	dfrag = mptcp_rtx_head(sk);
 	if (!dfrag)
-		goto unlock;
+		return;
 
 	ssk = mptcp_subflow_get_retrans(msk);
 	if (!ssk)
-		goto reset_unlock;
+		goto reset_timer;
 
 	lock_sock(ssk);
 
@@ -2333,9 +2297,52 @@ static void mptcp_worker(struct work_struct *work)
 	mptcp_set_timeout(sk, ssk);
 	release_sock(ssk);
 
-reset_unlock:
+reset_timer:
 	if (!mptcp_timer_pending(sk))
 		mptcp_reset_timer(sk);
+}
+
+static void mptcp_worker(struct work_struct *work)
+{
+	struct mptcp_sock *msk = container_of(work, struct mptcp_sock, work);
+	struct sock *sk = &msk->sk.icsk_inet.sk;
+	int state;
+
+	lock_sock(sk);
+	state = sk->sk_state;
+	if (unlikely(state == TCP_CLOSE))
+		goto unlock;
+
+	mptcp_check_data_fin_ack(sk);
+	__mptcp_flush_join_list(msk);
+
+	mptcp_check_fastclose(msk);
+
+	if (msk->pm.status)
+		mptcp_pm_nl_work(msk);
+
+	if (test_and_clear_bit(MPTCP_WORK_EOF, &msk->flags))
+		mptcp_check_for_eof(msk);
+
+	__mptcp_check_send_data_fin(sk);
+	mptcp_check_data_fin(sk);
+
+	/* There is no point in keeping around an orphaned sk timedout or
+	 * closed, but we need the msk around to reply to incoming DATA_FIN,
+	 * even if it is orphaned and in FIN_WAIT2 state
+	 */
+	if (sock_flag(sk, SOCK_DEAD) &&
+	    (mptcp_check_close_timeout(sk) || sk->sk_state == TCP_CLOSE)) {
+		inet_sk_state_store(sk, TCP_CLOSE);
+		__mptcp_destroy_sock(sk);
+		goto unlock;
+	}
+
+	if (test_and_clear_bit(MPTCP_WORK_CLOSE_SUBFLOW, &msk->flags))
+		__mptcp_close_subflow(msk);
+
+	if (test_and_clear_bit(MPTCP_WORK_RTX, &msk->flags))
+		__mptcp_retrans(sk);
 
 unlock:
 	release_sock(sk);