freebsd-skq/sys/sys/rmlock.h
mlaier 2ef34e9086 rmlock(9) two additions and one change/fix:
- add rm_try_rlock().
 - add RM_SLEEPABLE to use sx(9) as the back-end lock in order to sleep while
   holding the write lock.
 - change rm_noreadtoken to a cpu bitmask to indicate which CPUs need to go
   through the lock/unlock in order to synchronize.  As a side effect, this
   also avoids IPI to CPUs without any readers during rm_wlock.

Discussed with:		ups@, rwatson@ on arch@
Sponsored by:		Isilon Systems, Inc.
2010-09-01 19:50:03 +00:00

128 lines
4.4 KiB
C

/*-
* Copyright (c) 2007 Stephan Uphoff <ups@FreeBSD.org>
* 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 name of the author nor the names of any co-contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
*
* $FreeBSD$
*/
#ifndef _SYS_RMLOCK_H_
#define _SYS_RMLOCK_H_
#include <sys/mutex.h>
#include <sys/sx.h>
#include <sys/_lock.h>
#include <sys/_rmlock.h>
#ifdef _KERNEL
/*
* Flags passed to rm_init(9).
*/
#define RM_NOWITNESS 0x00000001
#define RM_RECURSE 0x00000002
#define RM_SLEEPABLE 0x00000004
void rm_init(struct rmlock *rm, const char *name);
void rm_init_flags(struct rmlock *rm, const char *name, int opts);
void rm_destroy(struct rmlock *rm);
int rm_wowned(struct rmlock *rm);
void rm_sysinit(void *arg);
void rm_sysinit_flags(void *arg);
void _rm_wlock_debug(struct rmlock *rm, const char *file, int line);
void _rm_wunlock_debug(struct rmlock *rm, const char *file, int line);
int _rm_rlock_debug(struct rmlock *rm, struct rm_priotracker *tracker,
int trylock, const char *file, int line);
void _rm_runlock_debug(struct rmlock *rm, struct rm_priotracker *tracker,
const char *file, int line);
void _rm_wlock(struct rmlock *rm);
void _rm_wunlock(struct rmlock *rm);
int _rm_rlock(struct rmlock *rm, struct rm_priotracker *tracker,
int trylock);
void _rm_runlock(struct rmlock *rm, struct rm_priotracker *tracker);
/*
* Public interface for lock operations.
*/
#ifndef LOCK_DEBUG
#error LOCK_DEBUG not defined, include <sys/lock.h> before <sys/rmlock.h>
#endif
#if LOCK_DEBUG > 0
#define rm_wlock(rm) _rm_wlock_debug((rm), LOCK_FILE, LOCK_LINE)
#define rm_wunlock(rm) _rm_wunlock_debug((rm), LOCK_FILE, LOCK_LINE)
#define rm_rlock(rm,tracker) \
((void)_rm_rlock_debug((rm),(tracker), 0, LOCK_FILE, LOCK_LINE ))
#define rm_try_rlock(rm,tracker) \
_rm_rlock_debug((rm),(tracker), 1, LOCK_FILE, LOCK_LINE )
#define rm_runlock(rm,tracker) \
_rm_runlock_debug((rm), (tracker), LOCK_FILE, LOCK_LINE )
#else
#define rm_wlock(rm) _rm_wlock((rm))
#define rm_wunlock(rm) _rm_wunlock((rm))
#define rm_rlock(rm,tracker) ((void)_rm_rlock((rm),(tracker), 0))
#define rm_try_rlock(rm,tracker) _rm_rlock((rm),(tracker), 1)
#define rm_runlock(rm,tracker) _rm_runlock((rm), (tracker))
#endif
struct rm_args {
struct rmlock *ra_rm;
const char *ra_desc;
};
struct rm_args_flags {
struct rmlock *ra_rm;
const char *ra_desc;
int ra_opts;
};
#define RM_SYSINIT(name, rm, desc) \
static struct rm_args name##_args = { \
(rm), \
(desc), \
}; \
SYSINIT(name##_rm_sysinit, SI_SUB_LOCK, SI_ORDER_MIDDLE, \
rm_sysinit, &name##_args); \
SYSUNINIT(name##_rm_sysuninit, SI_SUB_LOCK, SI_ORDER_MIDDLE, \
rm_destroy, (rm))
#define RM_SYSINIT_FLAGS(name, rm, desc, opts) \
static struct rm_args name##_args = { \
(rm), \
(desc), \
(opts), \
}; \
SYSINIT(name##_rm_sysinit, SI_SUB_LOCK, SI_ORDER_MIDDLE, \
rm_sysinit_flags, &name##_args); \
SYSUNINIT(name##_rm_sysuninit, SI_SUB_LOCK, SI_ORDER_MIDDLE, \
rm_destroy, (rm))
#endif /* _KERNEL */
#endif /* !_SYS_RMLOCK_H_ */