mptcp: drop WORKER_RUNNING status bit

Only mptcp_close() can actually cancel the workqueue,
no need to add and use this flag.

Reviewed-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net/mptcp/protocol.c

@@ -1862,7 +1862,6 @@ static void mptcp_worker(struct work_struct *work)
 	int state, ret;
 
 	lock_sock(sk);
-	set_bit(MPTCP_WORKER_RUNNING, &msk->flags);
 	state = sk->sk_state;
 	if (unlikely(state == TCP_CLOSE))
 		goto unlock;
@@ -1940,7 +1939,6 @@ static void mptcp_worker(struct work_struct *work)
 		mptcp_reset_timer(sk);
 
 unlock:
-	clear_bit(MPTCP_WORKER_RUNNING, &msk->flags);
 	release_sock(sk);
 	sock_put(sk);
 }
@@ -2011,11 +2009,7 @@ static void mptcp_cancel_work(struct sock *sk)
 {
 	struct mptcp_sock *msk = mptcp_sk(sk);
 
-	/* if called by the work itself, do not try to cancel the work, or
-	 * we will hang.
-	 */
-	if (!test_bit(MPTCP_WORKER_RUNNING, &msk->flags) &&
-	    cancel_work_sync(&msk->work))
+	if (cancel_work_sync(&msk->work))
 		__sock_put(sk);
 }
 

net/mptcp/protocol.h

@@ -91,7 +91,6 @@
 #define MPTCP_WORK_EOF		3
 #define MPTCP_FALLBACK_DONE	4
 #define MPTCP_WORK_CLOSE_SUBFLOW 5
-#define MPTCP_WORKER_RUNNING	6
 
 static inline bool before64(__u64 seq1, __u64 seq2)
 {