drbd: Turn no-tcp-cork into tcp-cork={yes|no}

Change the --no-tcp-cork drbdsetup command line option as well as
the no_cork netlink packet.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

drivers/block/drbd/drbd_receiver.c

@@ -5040,7 +5040,7 @@ int drbd_asender(struct drbd_thread *thi)
 	int expect   = header_size;
 	bool ping_timeout_active = false;
 	struct net_conf *nc;
-	int ping_timeo, no_cork, ping_int;
+	int ping_timeo, tcp_cork, ping_int;
 
 	current->policy = SCHED_RR;  /* Make this a realtime task! */
 	current->rt_priority = 2;    /* more important than all other tasks */
@@ -5051,7 +5051,7 @@ int drbd_asender(struct drbd_thread *thi)
 		rcu_read_lock();
 		nc = rcu_dereference(tconn->net_conf);
 		ping_timeo = nc->ping_timeo;
-		no_cork = nc->no_cork;
+		tcp_cork = nc->tcp_cork;
 		ping_int = nc->ping_int;
 		rcu_read_unlock();
 
@@ -5066,14 +5066,14 @@ int drbd_asender(struct drbd_thread *thi)
 
 		/* TODO: conditionally cork; it may hurt latency if we cork without
 		   much to send */
-		if (!no_cork)
+		if (tcp_cork)
 			drbd_tcp_cork(tconn->meta.socket);
 		if (tconn_finish_peer_reqs(tconn)) {
 			conn_err(tconn, "tconn_finish_peer_reqs() failed\n");
 			goto reconnect;
 		}
 		/* but unconditionally uncork unless disabled */
-		if (!no_cork)
+		if (tcp_cork)
 			drbd_tcp_uncork(tconn->meta.socket);
 
 		/* short circuit, recv_msg would return EINTR anyways. */

drivers/block/drbd/drbd_worker.c

@@ -1694,7 +1694,7 @@ int drbd_worker(struct drbd_thread *thi)
 
 			rcu_read_lock();
 			nc = rcu_dereference(tconn->net_conf);
-			cork = nc ? !nc->no_cork : 0;
+			cork = nc ? nc->tcp_cork : 0;
 			rcu_read_unlock();
 
 			if (tconn->data.socket && cork)

include/linux/drbd_genl.h

@@ -162,7 +162,7 @@ GENL_struct(DRBD_NLA_NET_CONF, 5, net_conf,
 	__u32_field_def(25,	GENLA_F_MANDATORY,	cong_extents, DRBD_CONG_EXTENTS_DEF)
 	__flg_field_def(26, GENLA_F_MANDATORY,	two_primaries, 0)
 	__flg_field(27, GENLA_F_MANDATORY | GENLA_F_INVARIANT,	want_lose)
-	__flg_field_def(28, GENLA_F_MANDATORY,	no_cork, 0)
+	__flg_field_def(28, GENLA_F_MANDATORY,	tcp_cork, 1)
 	__flg_field_def(29, GENLA_F_MANDATORY,	always_asbp, 0)
 	__flg_field(30, GENLA_F_MANDATORY | GENLA_F_INVARIANT,	dry_run)
 	__flg_field_def(31,	GENLA_F_MANDATORY,	use_rle, 0)