kernel-ark/include/linux/connector.h
Denis V. Lunev cd40b7d398 [NET]: make netlink user -> kernel interface synchronious
This patch make processing netlink user -> kernel messages synchronious.
This change was inspired by the talk with Alexey Kuznetsov about current
netlink messages processing. He says that he was badly wrong when introduced 
asynchronious user -> kernel communication.

The call netlink_unicast is the only path to send message to the kernel
netlink socket. But, unfortunately, it is also used to send data to the
user.

Before this change the user message has been attached to the socket queue
and sk->sk_data_ready was called. The process has been blocked until all
pending messages were processed. The bad thing is that this processing
may occur in the arbitrary process context.

This patch changes nlk->data_ready callback to get 1 skb and force packet
processing right in the netlink_unicast.

Kernel -> user path in netlink_unicast remains untouched.

EINTR processing for in netlink_run_queue was changed. It forces rtnl_lock
drop, but the process remains in the cycle until the message will be fully
processed. So, there is no need to use this kludges now.

Signed-off-by: Denis V. Lunev <den@openvz.org>
Acked-by: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
Signed-off-by: David S. Miller <davem@davemloft.net>
2007-10-10 21:15:29 -07:00

179 lines
3.8 KiB
C

/*
* connector.h
*
* 2004-2005 Copyright (c) Evgeniy Polyakov <johnpol@2ka.mipt.ru>
* All rights reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#ifndef __CONNECTOR_H
#define __CONNECTOR_H
#include <asm/types.h>
#define CN_IDX_CONNECTOR 0xffffffff
#define CN_VAL_CONNECTOR 0xffffffff
/*
* Process Events connector unique ids -- used for message routing
*/
#define CN_IDX_PROC 0x1
#define CN_VAL_PROC 0x1
#define CN_IDX_CIFS 0x2
#define CN_VAL_CIFS 0x1
#define CN_W1_IDX 0x3 /* w1 communication */
#define CN_W1_VAL 0x1
#define CN_NETLINK_USERS 4
/*
* Maximum connector's message size.
*/
#define CONNECTOR_MAX_MSG_SIZE 1024
/*
* idx and val are unique identifiers which
* are used for message routing and
* must be registered in connector.h for in-kernel usage.
*/
struct cb_id {
__u32 idx;
__u32 val;
};
struct cn_msg {
struct cb_id id;
__u32 seq;
__u32 ack;
__u16 len; /* Length of the following data */
__u16 flags;
__u8 data[0];
};
/*
* Notify structure - requests notification about
* registering/unregistering idx/val in range [first, first+range].
*/
struct cn_notify_req {
__u32 first;
__u32 range;
};
/*
* Main notification control message
* *_notify_num - number of appropriate cn_notify_req structures after
* this struct.
* group - notification receiver's idx.
* len - total length of the attached data.
*/
struct cn_ctl_msg {
__u32 idx_notify_num;
__u32 val_notify_num;
__u32 group;
__u32 len;
__u8 data[0];
};
#ifdef __KERNEL__
#include <asm/atomic.h>
#include <linux/list.h>
#include <linux/workqueue.h>
#include <net/sock.h>
#define CN_CBQ_NAMELEN 32
struct cn_queue_dev {
atomic_t refcnt;
unsigned char name[CN_CBQ_NAMELEN];
struct workqueue_struct *cn_queue;
struct list_head queue_list;
spinlock_t queue_lock;
int netlink_groups;
struct sock *nls;
};
struct cn_callback_id {
unsigned char name[CN_CBQ_NAMELEN];
struct cb_id id;
};
struct cn_callback_data {
void (*destruct_data) (void *);
void *ddata;
void *callback_priv;
void (*callback) (void *);
void *free;
};
struct cn_callback_entry {
struct list_head callback_entry;
struct cn_callback *cb;
struct work_struct work;
struct cn_queue_dev *pdev;
struct cn_callback_id id;
struct cn_callback_data data;
int seq, group;
struct sock *nls;
};
struct cn_ctl_entry {
struct list_head notify_entry;
struct cn_ctl_msg *msg;
};
struct cn_dev {
struct cb_id id;
u32 seq, groups;
struct sock *nls;
void (*input) (struct sk_buff *skb);
struct cn_queue_dev *cbdev;
};
int cn_add_callback(struct cb_id *, char *, void (*callback) (void *));
void cn_del_callback(struct cb_id *);
int cn_netlink_send(struct cn_msg *, u32, gfp_t);
int cn_queue_add_callback(struct cn_queue_dev *dev, char *name, struct cb_id *id, void (*callback)(void *));
void cn_queue_del_callback(struct cn_queue_dev *dev, struct cb_id *id);
struct cn_queue_dev *cn_queue_alloc_dev(char *name, struct sock *);
void cn_queue_free_dev(struct cn_queue_dev *dev);
int cn_cb_equal(struct cb_id *, struct cb_id *);
void cn_queue_wrapper(struct work_struct *work);
extern int cn_already_initialized;
#endif /* __KERNEL__ */
#endif /* __CONNECTOR_H */