Merge branch 'mptcp-cleanups'

Mat Martineau says:

====================
MPTCP: Cleanup and address advertisement fixes

This patch series contains cleanup and fixes we have been testing in the
MPTCP tree. MPTCP uses TCP option headers to advertise additional
address information after an initial connection is established. The main
fixes here deal with making those advertisements more reliable and
improving the way subflows are created after an advertisement is
received.

Patches 1, 2, 4, 10, and 12 are for various cleanup or refactoring.

Patch 3 skips an extra connection attempt if there's already a subflow
connection for the newly received advertisement.

Patches 5, 6, and 7 make sure that the next address is advertised when
there are multiple addresses to share, the advertisement has been
retried, and the peer has not echoed the advertisement. Self tests are
updated.

Patches 8 and 9 fix a problem similar to 5/6/7, but covers a case where
the failure was due to a subflow connection not completing.

Patches 11 and 13 send a bare ack to revoke an advertisement rather than
waiting for other activity to trigger a packet send. This mirrors the
way acks are sent for new advertisements. Self test is included.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 11 insertions, 31 deletions

diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index 1590b9d4cde2..171b77537dcb 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -2047,28 +2047,21 @@ out_err:
 	return copied;
 }
 
-static void mptcp_retransmit_handler(struct sock *sk)
-{
-	struct mptcp_sock *msk = mptcp_sk(sk);
-
-	set_bit(MPTCP_WORK_RTX, &msk->flags);
-	mptcp_schedule_work(sk);
-}
-
 static void mptcp_retransmit_timer(struct timer_list *t)
 {
 	struct inet_connection_sock *icsk = from_timer(icsk, t,
 						       icsk_retransmit_timer);
 	struct sock *sk = &icsk->icsk_inet.sk;
+	struct mptcp_sock *msk = mptcp_sk(sk);
 
 	bh_lock_sock(sk);
 	if (!sock_owned_by_user(sk)) {
-		mptcp_retransmit_handler(sk);
+		/* we need a process context to retransmit */
+		if (!test_and_set_bit(MPTCP_WORK_RTX, &msk->flags))
+			mptcp_schedule_work(sk);
 	} else {
 		/* delegate our work to tcp_release_cb() */
-		if (!test_and_set_bit(TCP_WRITE_TIMER_DEFERRED,
-				      &sk->sk_tsq_flags))
-			sock_hold(sk);
+		set_bit(MPTCP_RETRANSMIT, &msk->flags);
 	}
 	bh_unlock_sock(sk);
 	sock_put(sk);
@@ -2958,17 +2951,16 @@ void __mptcp_check_push(struct sock *sk, struct sock *ssk)
 	}
 }
 
-#define MPTCP_DEFERRED_ALL (TCPF_WRITE_TIMER_DEFERRED)
-
 /* processes deferred events and flush wmem */
 static void mptcp_release_cb(struct sock *sk)
 {
-	unsigned long flags, nflags;
-
 	for (;;) {
-		flags = 0;
+		unsigned long flags = 0;
+
 		if (test_and_clear_bit(MPTCP_PUSH_PENDING, &mptcp_sk(sk)->flags))
 			flags |= BIT(MPTCP_PUSH_PENDING);
+		if (test_and_clear_bit(MPTCP_RETRANSMIT, &mptcp_sk(sk)->flags))
+			flags |= BIT(MPTCP_RETRANSMIT);
 		if (!flags)
 			break;
 
@@ -2983,6 +2975,8 @@ static void mptcp_release_cb(struct sock *sk)
 		spin_unlock_bh(&sk->sk_lock.slock);
 		if (flags & BIT(MPTCP_PUSH_PENDING))
 			__mptcp_push_pending(sk, 0);
+		if (flags & BIT(MPTCP_RETRANSMIT))
+			__mptcp_retrans(sk);
 
 		cond_resched();
 		spin_lock_bh(&sk->sk_lock.slock);
@@ -2998,20 +2992,6 @@ static void mptcp_release_cb(struct sock *sk)
 	 */
 	__mptcp_update_wmem(sk);
 	__mptcp_update_rmem(sk);
-
-	do {
-		flags = sk->sk_tsq_flags;
-		if (!(flags & MPTCP_DEFERRED_ALL))
-			return;
-		nflags = flags & ~MPTCP_DEFERRED_ALL;
-	} while (cmpxchg(&sk->sk_tsq_flags, flags, nflags) != flags);
-
-	sock_release_ownership(sk);
-
-	if (flags & TCPF_WRITE_TIMER_DEFERRED) {
-		mptcp_retransmit_handler(sk);
-		__sock_put(sk);
-	}
 }
 
 void mptcp_subflow_process_delegated(struct sock *ssk)