tipc: simplify connection congestion handling

As a consequence of the recently introduced serialized access
to the socket in commit 8d94168a761819d10252bab1f8de6d7b202c3baa
("tipc: same receive code path for connection protocol and data
messages") we can make a number of simplifications in the
detection and handling of connection congestion situations.

- We don't need to keep two counters, one for sent messages and one
  for acked messages. There is no longer any risk for races between
  acknowledge messages arriving in BH and data message sending
  running in user context. So we merge this into one counter,
  'sent_unacked', which is incremented at sending and subtracted
  from at acknowledge reception.

- We don't need to set the 'congested' field in tipc_port to
  true before we sent the message, and clear it when sending
  is successful. (As a matter of fact, it was never necessary;
  the field was set in link_schedule_port() before any wakeup
  could arrive anyway.)

- We keep the conditions for link congestion and connection connection
  congestion separated. There would otherwise be a risk that an arriving
  acknowledge message may wake up a user sleeping because of link
  congestion.

- We can simplify reception of acknowledge messages.

We also make some cosmetic/structural changes:

- We rename the 'congested' field to the more correct 'link_cong´.

- We rename 'conn_unacked' to 'rcv_unacked'

- We move the above mentioned fields from struct tipc_port to
  struct tipc_sock.

Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Reviewed-by: Erik Hugne <erik.hugne@ericsson.com>
Reviewed-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 0 insertions, 16 deletions

diff --git a/net/tipc/port.h b/net/tipc/port.h
index 3a4f808..0e47052 100644
--- a/net/tipc/port.h
+++ b/net/tipc/port.h
@@ -53,17 +53,13 @@
  * @connected: non-zero if port is currently connected to a peer port
  * @conn_type: TIPC type used when connection was established
  * @conn_instance: TIPC instance used when connection was established
- * @conn_unacked: number of unacknowledged messages received from peer port
  * @published: non-zero if port has one or more associated names
- * @congested: non-zero if cannot send because of link or port congestion
  * @max_pkt: maximum packet size "hint" used when building messages sent by port
  * @ref: unique reference to port in TIPC object registry
  * @phdr: preformatted message header used when sending messages
  * @port_list: adjacent ports in TIPC's global list of ports
  * @wait_list: adjacent ports in list of ports waiting on link congestion
  * @waiting_pkts:
- * @sent: # of non-empty messages sent by port
- * @acked: # of non-empty message acknowledgements from connected port's peer
  * @publications: list of publications for port
  * @pub_count: total # of publications port has made during its lifetime
  * @probing_state:
@@ -76,17 +72,13 @@ struct tipc_port {
 	int connected;
 	u32 conn_type;
 	u32 conn_instance;
-	u32 conn_unacked;
 	int published;
-	u32 congested;
 	u32 max_pkt;
 	u32 ref;
 	struct tipc_msg phdr;
 	struct list_head port_list;
 	struct list_head wait_list;
 	u32 waiting_pkts;
-	u32 sent;
-	u32 acked;
 	struct list_head publications;
 	u32 pub_count;
 	u32 probing_state;
@@ -120,8 +112,6 @@ int tipc_port_disconnect(u32 portref);
 
 int tipc_port_shutdown(u32 ref);
 
-void tipc_port_wakeup(struct tipc_port *port);
-
 /*
  * The following routines require that the port be locked on entry
  */
@@ -161,12 +151,6 @@ static inline void tipc_port_unlock(struct tipc_port *p_ptr)
 	spin_unlock_bh(p_ptr->lock);
 }
 
-static inline int tipc_port_congested(struct tipc_port *p_ptr)
-{
-	return ((p_ptr->sent - p_ptr->acked) >= TIPC_FLOWCTRL_WIN);
-}
-
-
 static inline u32 tipc_port_peernode(struct tipc_port *p_ptr)
 {
 	return msg_destnode(&p_ptr->phdr);