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add something like pthread_once().

This commit is contained in:
yamt 2005-10-29 11:13:21 +00:00
parent 54f971f435
commit 8d3549ebb0
2 changed files with 114 additions and 0 deletions
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58
sys/kern/subr_once.c Normal file
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/* $NetBSD: subr_once.c,v 1.1 2005/10/29 11:13:21 yamt Exp $ */
/*-
* Copyright (c)2005 YAMAMOTO Takashi,
* 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 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.
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: subr_once.c,v 1.1 2005/10/29 11:13:21 yamt Exp $");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/proc.h>
#include <sys/once.h>
void
_run_once(once_t *o, void (*fn)(void))
{
simple_lock(&o->o_lock);
while ((o->o_flags & ONCE_RUNNING) != 0) {
ltsleep(o, PUSER, "runonce", 0, &o->o_lock);
}
if (o->o_flags & ONCE_DONE) {
goto done;
}
o->o_flags |= ONCE_RUNNING;
simple_unlock(&o->o_lock);
(*fn)();
simple_lock(&o->o_lock);
o->o_flags = ONCE_DONE;
wakeup(o);
done:
simple_unlock(&o->o_lock);
}

56
sys/sys/once.h Normal file
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/* $NetBSD: once.h,v 1.1 2005/10/29 11:13:21 yamt Exp $ */
/*-
* Copyright (c)2005 YAMAMOTO Takashi,
* 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 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.
*/
#if !defined(_SYS_ONCE_H_)
#define _SYS_ONCE_H_
#include <sys/lock.h>
typedef struct {
struct simplelock o_lock;
int o_flags;
#define ONCE_RUNNING 1
#define ONCE_DONE 2
} once_t;
void _run_once(once_t *, void (*)(void));
#define ONCE_DECL(o) \
once_t (o) = { \
.o_lock = SIMPLELOCK_INITIALIZER, \
.o_flags = 0, \
};
#define RUN_ONCE(o, fn) \
do { \
if (__predict_false(((o)->o_flags & ONCE_DONE) == 0)) { \
_run_once((o), (fn)); \
} \
} while (0 /* CONSTCOND */)
#endif /* !defined(_SYS_ONCE_H_) */