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linux-next/include/linux/connector.h
Patrick McHardy 04f482faf5 connector: convert to synchronous netlink message processing
Commits 01a16b21 (netlink: kill eff_cap from struct netlink_skb_parms)
and c53fa1ed (netlink: kill loginuid/sessionid/sid members from struct
netlink_skb_parms) removed some members from struct netlink_skb_parms
that depend on the current context, all netlink users are now required
to do synchronous message processing.

connector however queues received messages and processes them in a work
queue, which is not valid anymore. This patch converts connector to do
synchronous message processing by invoking the registered callback handler
directly from the netlink receive function.

In order to avoid invoking the callback with connector locks held, a
reference count is added to struct cn_callback_entry, the reference
is taken when finding a matching callback entry on the device's queue_list
and released after the callback handler has been invoked.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Acked-by: Evgeniy Polyakov <zbr@ioremap.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2011-03-30 17:14:33 -07:00

141 lines
3.4 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 <linux/types.h>
/*
* 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_IDX_V86D 0x4
#define CN_VAL_V86D_UVESAFB 0x1
#define CN_IDX_BB 0x5 /* BlackBoard, from the TSP GPL sampling framework */
#define CN_DST_IDX 0x6
#define CN_DST_VAL 0x1
#define CN_IDX_DM 0x7 /* Device Mapper */
#define CN_VAL_DM_USERSPACE_LOG 0x1
#define CN_IDX_DRBD 0x8
#define CN_VAL_DRBD 0x1
#define CN_KVP_IDX 0x9 /* HyperV KVP */
#define CN_NETLINK_USERS 9
/*
* Maximum connector's message size.
*/
#define CONNECTOR_MAX_MSG_SIZE 16384
/*
* 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];
};
#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 list_head queue_list;
spinlock_t queue_lock;
struct sock *nls;
};
struct cn_callback_id {
unsigned char name[CN_CBQ_NAMELEN];
struct cb_id id;
};
struct cn_callback_entry {
struct list_head callback_entry;
atomic_t refcnt;
struct cn_queue_dev *pdev;
struct cn_callback_id id;
void (*callback) (struct cn_msg *, struct netlink_skb_parms *);
u32 seq, group;
};
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 *id, const char *name,
void (*callback)(struct cn_msg *, struct netlink_skb_parms *));
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, const char *name,
struct cb_id *id,
void (*callback)(struct cn_msg *, struct netlink_skb_parms *));
void cn_queue_del_callback(struct cn_queue_dev *dev, struct cb_id *id);
void cn_queue_release_callback(struct cn_callback_entry *);
struct cn_queue_dev *cn_queue_alloc_dev(const char *name, struct sock *);
void cn_queue_free_dev(struct cn_queue_dev *dev);
int cn_cb_equal(struct cb_id *, struct cb_id *);
#endif /* __KERNEL__ */
#endif /* __CONNECTOR_H */