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/*
* Copyright (C) 2001 Jason Evans <jasone@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(s), this list of conditions and the following disclaimer as
* the first lines of this file unmodified other than the possible
* addition of one or more copyright notices.
* 2. Redistributions in binary form must reproduce the above copyright
* notice(s), 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 COPYRIGHT HOLDER(S) ``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 COPYRIGHT HOLDER(S) 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_SX_H_
#define _SYS_SX_H_
#ifndef LOCORE
#include <sys/_lock.h>
#include <sys/_mutex.h>
#include <sys/condvar.h> /* XXX */
struct sx {
struct lock_object sx_object; /* Common lock properties. */
struct mtx sx_lock; /* General protection lock. */
int sx_cnt; /* -1: xlock, > 0: slock count. */
struct cv sx_shrd_cv; /* slock waiters. */
int sx_shrd_wcnt; /* Number of slock waiters. */
struct cv sx_excl_cv; /* xlock waiters. */
int sx_excl_wcnt; /* Number of xlock waiters. */
struct proc *sx_xholder; /* Thread presently holding xlock. */
};
#ifdef _KERNEL
void sx_init(struct sx *sx, const char *description);
void sx_destroy(struct sx *sx);
void _sx_slock(struct sx *sx, const char *file, int line);
void _sx_xlock(struct sx *sx, const char *file, int line);
int _sx_try_slock(struct sx *sx, const char *file, int line);
int _sx_try_xlock(struct sx *sx, const char *file, int line);
void _sx_sunlock(struct sx *sx, const char *file, int line);
void _sx_xunlock(struct sx *sx, const char *file, int line);
int _sx_try_upgrade(struct sx *sx, const char *file, int line);
void _sx_downgrade(struct sx *sx, const char *file, int line);
#define sx_slock(sx) _sx_slock((sx), __FILE__, __LINE__)
#define sx_xlock(sx) _sx_xlock((sx), __FILE__, __LINE__)
#define sx_try_slock(sx) _sx_try_slock((sx), __FILE__, __LINE__)
#define sx_try_xlock(sx) _sx_try_xlock((sx), __FILE__, __LINE__)
#define sx_sunlock(sx) _sx_sunlock((sx), __FILE__, __LINE__)
#define sx_xunlock(sx) _sx_xunlock((sx), __FILE__, __LINE__)
#define sx_try_upgrade(sx) _sx_try_upgrade((sx), __FILE__, __LINE__)
#define sx_downgrade(sx) _sx_downgrade((sx), __FILE__, __LINE__)
#ifdef INVARIANTS
/*
* In the non-WITNESS case, SX_ASSERT_LOCKED() and SX_ASSERT_SLOCKED()
* can only detect that at least *some* thread owns an slock, but it cannot
* guarantee that *this* thread owns an slock.
*/
#ifdef WITNESS
#define _SX_ASSERT_LOCKED(sx, file, line) \
witness_assert(&(sx)->sx_object, LA_LOCKED, file, line)
#define _SX_ASSERT_SLOCKED(sx, file, line) \
witness_assert(&(sx)->sx_object, LA_SLOCKED, file, line)
#else
#define _SX_ASSERT_LOCKED(sx, file, line) do { \
KASSERT(((sx)->sx_cnt > 0 || (sx)->sx_xholder == curproc), \
("Lock %s not locked @ %s:%d", (sx)->sx_object.lo_name, \
file, line)); \
} while (0)
#define _SX_ASSERT_SLOCKED(sx, file, line) do { \
KASSERT(((sx)->sx_cnt > 0), ("Lock %s not share locked @ %s:%d",\
(sx)->sx_object.lo_name, file, line)); \
} while (0)
#endif
#define SX_ASSERT_LOCKED(sx) _SX_ASSERT_LOCKED((sx), __FILE__, __LINE__)
#define SX_ASSERT_SLOCKED(sx) _SX_ASSERT_SLOCKED((sx), __FILE__, __LINE__)
/*
* SX_ASSERT_XLOCKED() detects and guarantees that *we* own the xlock.
*/
#define _SX_ASSERT_XLOCKED(sx, file, line) do { \
KASSERT(((sx)->sx_xholder == curproc), \
("Lock %s not exclusively locked @ %s:%d", \
(sx)->sx_object.lo_name, file, line)); \
} while (0)
#define SX_ASSERT_XLOCKED(sx) _SX_ASSERT_XLOCKED((sx), __FILE__, __LINE__)
#else /* INVARIANTS */
#define SX_ASSERT_SLOCKED(sx)
#define SX_ASSERT_XLOCKED(sx)
#define _SX_ASSERT_SLOCKED(sx, file, line)
#define _SX_ASSERT_XLOCKED(sx, file, line)
#endif /* INVARIANTS */
#endif /* _KERNEL */
#endif /* !LOCORE */
#endif /* _SYS_SX_H_ */
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