mptcp: move subflow close loop after sk close check

In case mptcp socket is already dead the entire mptcp socket
will be freed. We can avoid the close check in this case.

Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: Florian Westphal <fw@strlen.de>

net/mptcp/protocol.c

@@ -2242,9 +2242,6 @@ static void mptcp_worker(struct work_struct *work)
 
 	mptcp_check_fastclose(msk);
 
-	if (test_and_clear_bit(MPTCP_WORK_CLOSE_SUBFLOW, &msk->flags))
-		__mptcp_close_subflow(msk);
-
 	if (msk->pm.status)
 		mptcp_pm_nl_work(msk);
 
@@ -2266,6 +2263,9 @@ static void mptcp_worker(struct work_struct *work)
 		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;