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linux/net/tipc/port.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

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/*
* net/tipc/port.h: Include file for TIPC port code
*
* Copyright (c) 1994-2007, 2014, Ericsson AB
* Copyright (c) 2004-2007, 2010-2013, Wind River Systems
* 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_PORT_H
#define _TIPC_PORT_H
#include "ref.h"
#include "net.h"
#include "msg.h"
#include "node_subscr.h"
#define TIPC_CONNACK_INTV 256
#define TIPC_FLOWCTRL_WIN (TIPC_CONNACK_INTV * 2)
#define TIPC_CONN_OVERLOAD_LIMIT ((TIPC_FLOWCTRL_WIN * 2 + 1) * \
SKB_TRUESIZE(TIPC_MAX_USER_MSG_SIZE))
/**
* struct tipc_port - TIPC port structure
* @lock: pointer to spinlock for controlling access to port
* @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
* @published: non-zero if port has one or more associated names
* @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:
* @publications: list of publications for port
* @pub_count: total # of publications port has made during its lifetime
* @probing_state:
* @probing_interval:
* @timer_ref:
* @subscription: "node down" subscription used to terminate failed connections
*/
struct tipc_port {
spinlock_t *lock;
int connected;
u32 conn_type;
u32 conn_instance;
int published;
u32 max_pkt;
u32 ref;
struct tipc_msg phdr;
struct list_head port_list;
struct list_head wait_list;
u32 waiting_pkts;
struct list_head publications;
u32 pub_count;
u32 probing_state;
u32 probing_interval;
struct timer_list timer;
struct tipc_node_subscr subscription;
};
extern spinlock_t tipc_port_list_lock;
struct tipc_port_list;
/*
* TIPC port manipulation routines
*/
u32 tipc_port_init(struct tipc_port *p_ptr,
const unsigned int importance);
void tipc_acknowledge(u32 port_ref, u32 ack);
void tipc_port_destroy(struct tipc_port *p_ptr);
int tipc_publish(struct tipc_port *p_ptr, unsigned int scope,
struct tipc_name_seq const *name_seq);
int tipc_withdraw(struct tipc_port *p_ptr, unsigned int scope,
struct tipc_name_seq const *name_seq);
int tipc_port_connect(u32 portref, struct tipc_portid const *port);
int tipc_port_disconnect(u32 portref);
int tipc_port_shutdown(u32 ref);
/*
* The following routines require that the port be locked on entry
*/
int __tipc_port_disconnect(struct tipc_port *tp_ptr);
int __tipc_port_connect(u32 ref, struct tipc_port *p_ptr,
struct tipc_portid const *peer);
int tipc_port_peer_msg(struct tipc_port *p_ptr, struct tipc_msg *msg);
/*
* TIPC messaging routines
*/
int tipc_port_mcast_xmit(struct tipc_port *port,
struct tipc_name_seq const *seq,
struct iovec const *msg,
unsigned int len);
struct sk_buff *tipc_port_get_ports(void);
void tipc_port_mcast_rcv(struct sk_buff *buf, struct tipc_port_list *dp);
void tipc_port_reinit(void);
/**
* tipc_port_lock - lock port instance referred to and return its pointer
*/
static inline struct tipc_port *tipc_port_lock(u32 ref)
{
return (struct tipc_port *)tipc_ref_lock(ref);
}
/**
* tipc_port_unlock - unlock a port instance
*
* Can use pointer instead of tipc_ref_unlock() since port is already locked.
*/
static inline void tipc_port_unlock(struct tipc_port *p_ptr)
{
spin_unlock_bh(p_ptr->lock);
}
static inline u32 tipc_port_peernode(struct tipc_port *p_ptr)
{
return msg_destnode(&p_ptr->phdr);
}
static inline u32 tipc_port_peerport(struct tipc_port *p_ptr)
{
return msg_destport(&p_ptr->phdr);
}
static inline bool tipc_port_unreliable(struct tipc_port *port)
{
return msg_src_droppable(&port->phdr) != 0;
}
static inline void tipc_port_set_unreliable(struct tipc_port *port,
bool unreliable)
{
msg_set_src_droppable(&port->phdr, unreliable ? 1 : 0);
}
static inline bool tipc_port_unreturnable(struct tipc_port *port)
{
return msg_dest_droppable(&port->phdr) != 0;
}
static inline void tipc_port_set_unreturnable(struct tipc_port *port,
bool unreturnable)
{
msg_set_dest_droppable(&port->phdr, unreturnable ? 1 : 0);
}
static inline int tipc_port_importance(struct tipc_port *port)
{
return msg_importance(&port->phdr);
}
static inline void tipc_port_set_importance(struct tipc_port *port, int imp)
{
msg_set_importance(&port->phdr, (u32)imp);
}
#endif
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