freebsd-nq/sys/fs/devfs/devfs_int.h
Konstantin Belousov 82f4d64035 Implement the per-open file data for the cdev.
The patch does not change the cdevsw KBI. Management of the data is
provided by the functions
int	devfs_set_cdevpriv(void *priv, cdevpriv_dtr_t dtr);
int	devfs_get_cdevpriv(void **datap);
void	devfs_clear_cdevpriv(void);
All of the functions are supposed to be called from the cdevsw method
contexts.

- devfs_set_cdevpriv assigns the priv as private data for the file
  descriptor which is used to initiate currently performed driver
  operation. dtr is the function that will be called when either the
  last refernce to the file goes away, the device is destroyed  or
  devfs_clear_cdevpriv is called.
- devfs_get_cdevpriv is the obvious accessor.
- devfs_clear_cdevpriv allows to clear the private data for the still
  open file.

Implementation keeps the driver-supplied pointers in the struct
cdev_privdata, that is referenced both from the struct file and struct
cdev, and cannot outlive any of the referee.

Man pages will be provided after the KPI stabilizes.

Reviewed by:	jhb
Useful suggestions from:	jeff, antoine
Debugging help and tested by:	pho
MFC after:	1 month
2008-05-21 09:31:44 +00:00

87 lines
2.6 KiB
C

/*-
* Copyright (c) 2005 Poul-Henning Kamp. 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. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
*
* $FreeBSD$
*/
/*
* This file documents a private interface and it SHALL only be used
* by kern/kern_conf.c and fs/devfs/...
*/
#ifndef _FS_DEVFS_DEVFS_INT_H_
#define _FS_DEVFS_DEVFS_INT_H_
#include <sys/queue.h>
#ifdef _KERNEL
struct devfs_dirent;
struct cdev_privdata {
struct file *cdpd_fp;
void *cdpd_data;
void (*cdpd_dtr)(void *);
LIST_ENTRY(cdev_privdata) cdpd_list;
};
struct cdev_priv {
struct cdev cdp_c;
TAILQ_ENTRY(cdev_priv) cdp_list;
u_int cdp_inode;
u_int cdp_flags;
#define CDP_ACTIVE (1 << 0)
#define CDP_SCHED_DTR (1 << 1)
u_int cdp_inuse;
u_int cdp_maxdirent;
struct devfs_dirent **cdp_dirents;
struct devfs_dirent *cdp_dirent0;
TAILQ_ENTRY(cdev_priv) cdp_dtr_list;
void (*cdp_dtr_cb)(void *);
void *cdp_dtr_cb_arg;
LIST_HEAD(, cdev_privdata) cdp_fdpriv;
};
struct cdev *devfs_alloc(void);
void devfs_free(struct cdev *);
void devfs_create(struct cdev *dev);
void devfs_destroy(struct cdev *dev);
void devfs_destroy_cdevpriv(struct cdev_privdata *p);
extern struct unrhdr *devfs_inos;
extern struct mtx devmtx;
extern struct mtx devfs_de_interlock;
extern struct sx clone_drain_lock;
extern struct mtx cdevpriv_mtx;
extern TAILQ_HEAD(cdev_priv_list, cdev_priv) cdevp_list;
#endif /* _KERNEL */
#endif /* !_FS_DEVFS_DEVFS_INT_H_ */