linux/net/tipc/socket.h
Jon Paul Maloy 60120526c2 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>
2014-06-27 12:50:56 -07:00

89 lines
3.2 KiB
C

/* net/tipc/socket.h: Include file for TIPC socket code
*
* Copyright (c) 2014, Ericsson AB
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the names of the copyright holders nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* Alternatively, this software may be distributed under the terms of the
* GNU General Public License ("GPL") version 2 as published by the Free
* Software Foundation.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef _TIPC_SOCK_H
#define _TIPC_SOCK_H
#include "port.h"
#include <net/sock.h>
#define TIPC_CONN_OK 0
#define TIPC_CONN_PROBING 1
/**
* struct tipc_sock - TIPC socket structure
* @sk: socket - interacts with 'port' and with user via the socket API
* @port: port - interacts with 'sk' and with the rest of the TIPC stack
* @peer_name: the peer of the connection, if any
* @conn_timeout: the time we can wait for an unresponded setup request
* @dupl_rcvcnt: number of bytes counted twice, in both backlog and rcv queue
* @link_cong: non-zero if owner must sleep because of link congestion
* @sent_unacked: # messages sent by socket, and not yet acked by peer
* @rcv_unacked: # messages read by user, but not yet acked back to peer
*/
struct tipc_sock {
struct sock sk;
struct tipc_port port;
unsigned int conn_timeout;
atomic_t dupl_rcvcnt;
int link_cong;
uint sent_unacked;
uint rcv_unacked;
};
static inline struct tipc_sock *tipc_sk(const struct sock *sk)
{
return container_of(sk, struct tipc_sock, sk);
}
static inline struct tipc_sock *tipc_port_to_sock(const struct tipc_port *port)
{
return container_of(port, struct tipc_sock, port);
}
static inline void tipc_sock_wakeup(struct tipc_sock *tsk)
{
tsk->sk.sk_write_space(&tsk->sk);
}
static inline int tipc_sk_conn_cong(struct tipc_sock *tsk)
{
return tsk->sent_unacked >= TIPC_FLOWCTRL_WIN;
}
int tipc_sk_rcv(struct sk_buff *buf);
#endif