freebsd-dev/sys/fs/devfs/devfs_int.h
Konstantin Belousov de10ffa527 Since rev. 1.199 of sys/kern/kern_conf.c, the thread that calls
destroy_dev() from d_close() cdev method would self-deadlock.
devfs_close() bump device thread reference counter, and destroy_dev()
sleeps, waiting for si_threadcount to reach zero for cdev without
d_purge method.

destroy_dev_sched() could be used instead from d_close(), to
schedule execution of destroy_dev() in another context. The
destroy_dev_sched_drain() function can be used to drain the scheduled
calls to destroy_dev_sched(). Similarly, drain_dev_clone_events() drains
the events clone to make sure no lingering devices are left after
dev_clone event handler deregistered.

make_dev_credf(MAKEDEV_REF) function should be used from dev_clone
event handlers instead of make_dev()/make_dev_cred() to ensure that created
device has reference counter bumped before cdev mutex is dropped inside
make_dev().

Reviewed by:	tegge (early versions), njl (programming interface)
Debugging help and testing by:	Peter Holm
Approved by:	re (kensmith)
2007-07-03 17:42:37 +00:00

76 lines
2.3 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_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;
};
struct cdev *devfs_alloc(void);
void devfs_free(struct cdev *);
void devfs_create(struct cdev *dev);
void devfs_destroy(struct cdev *dev);
extern struct unrhdr *devfs_inos;
extern struct mtx devmtx;
extern struct mtx devfs_de_interlock;
extern struct sx clone_drain_lock;
extern TAILQ_HEAD(cdev_priv_list, cdev_priv) cdevp_list;
#endif /* _KERNEL */
#endif /* !_FS_DEVFS_DEVFS_INT_H_ */