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/*-
* Copyright (c) 2007 Pawel Jakub Dawidek <pjd@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.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHORS 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 AUTHORS 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 _OPENSOLARIS_SYS_RWLOCK_H_
#define _OPENSOLARIS_SYS_RWLOCK_H_
#include <sys/param.h>
#include <sys/proc.h>
#include <sys/lock.h>
#include <sys/sx.h>
#ifdef _KERNEL
typedef enum {
RW_DEFAULT = 4 /* kernel default rwlock */
} krw_type_t;
typedef enum {
RW_WRITER,
RW_READER
} krw_t;
typedef struct sx krwlock_t;
#ifndef DEBUG
#define RW_FLAGS (SX_DUPOK | SX_NOWITNESS)
#else
#define RW_FLAGS (SX_DUPOK)
#endif
#define RW_READ_HELD(x) (rw_read_held((x)))
#define RW_WRITE_HELD(x) (rw_write_held((x)))
#define RW_LOCK_HELD(x) (rw_lock_held((x)))
#define RW_ISWRITER(x) (rw_iswriter(x))
#define rw_init(lock, desc, type, arg) do { \
const char *_name; \
ASSERT((type) == 0 || (type) == RW_DEFAULT); \
KASSERT(((lock)->lock_object.lo_flags & LO_ALLMASK) != \
LO_EXPECTED, ("lock %s already initialized", #lock)); \
bzero((lock), sizeof(struct sx)); \
for (_name = #lock; *_name != '\0'; _name++) { \
if (*_name >= 'a' && *_name <= 'z') \
break; \
} \
if (*_name == '\0') \
_name = #lock; \
sx_init_flags((lock), _name, RW_FLAGS); \
} while (0)
#define rw_destroy(lock) sx_destroy(lock)
#define rw_enter(lock, how) do { \
if ((how) == RW_READER) \
sx_slock(lock); \
else /* if ((how) == RW_WRITER) */ \
sx_xlock(lock); \
} while (0)
#define rw_tryenter(lock, how) ((how) == RW_READER ? sx_try_slock(lock) : sx_try_xlock(lock))
#define rw_exit(lock) sx_unlock(lock)
#define rw_downgrade(lock) sx_downgrade(lock)
#define rw_tryupgrade(lock) sx_try_upgrade(lock)
#define rw_read_held(lock) ((lock)->sx_lock != SX_LOCK_UNLOCKED && ((lock)->sx_lock & SX_LOCK_SHARED))
#define rw_write_held(lock) sx_xlocked(lock)
#define rw_lock_held(lock) (rw_read_held(lock) || rw_write_held(lock))
#define rw_iswriter(lock) sx_xlocked(lock)
/* TODO: Change to sx_xholder() once it is moved from kern_sx.c to sx.h. */
#define rw_owner(lock) ((lock)->sx_lock & SX_LOCK_SHARED ? NULL : (struct thread *)SX_OWNER((lock)->sx_lock))
#endif /* defined(_KERNEL) */
#endif /* _OPENSOLARIS_SYS_RWLOCK_H_ */
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