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/*
* Copyright (C) 2007-2010 Lawrence Livermore National Security, LLC.
* Copyright (C) 2007 The Regents of the University of California.
* Produced at Lawrence Livermore National Laboratory (cf, DISCLAIMER).
* Written by Brian Behlendorf <behlendorf1@llnl.gov>.
* UCRL-CODE-235197
*
* This file is part of the SPL, Solaris Porting Layer.
* For details, see <http://zfsonlinux.org/>.
*
* The SPL is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version.
*
* The SPL is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* for more details.
*
* You should have received a copy of the GNU General Public License along
* with the SPL. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef _SPL_CONDVAR_H
#define _SPL_CONDVAR_H
#include <linux/module.h>
#include <sys/kmem.h>
#include <sys/mutex.h>
#include <sys/callo.h>
#include <sys/wait.h>
#include <sys/time.h>
/*
* cv_timedwait() is similar to cv_wait() except that it additionally expects
* a timeout value specified in ticks. When woken by cv_signal() or
* cv_broadcast() it returns 1, otherwise when the timeout is reached -1 is
* returned.
*
* cv_timedwait_sig() behaves the same as cv_timedwait() but blocks
* interruptibly and can be woken by a signal (EINTR, ERESTART). When
* this occurs 0 is returned.
*
* cv_timedwait_io() and cv_timedwait_sig_io() are variants of cv_timedwait()
* and cv_timedwait_sig() which should be used when waiting for outstanding
* IO to complete. They are responsible for updating the iowait accounting
* when this is supported by the platform.
*
* cv_timedwait_hires() and cv_timedwait_sig_hires() are high resolution
* versions of cv_timedwait() and cv_timedwait_sig(). They expect the timeout
* to be specified as a hrtime_t allowing for timeouts of less than a tick.
*
* N.B. The return values differ slightly from the illumos implementation
* which returns the time remaining, instead of 1, when woken. They both
* return -1 on timeout. Consumers which need to know the time remaining
* are responsible for tracking it themselves.
*/
/*
* The kcondvar_t struct is protected by mutex taken externally before
* calling any of the wait/signal funs, and passed into the wait funs.
*/
#define CV_MAGIC 0x346545f4
#define CV_DESTROY 0x346545f5
typedef struct {
int cv_magic;
spl_wait_queue_head_t cv_event;
spl_wait_queue_head_t cv_destroy;
atomic_t cv_refs;
atomic_t cv_waiters;
kmutex_t *cv_mutex;
} kcondvar_t;
typedef enum { CV_DEFAULT = 0, CV_DRIVER } kcv_type_t;
extern void __cv_init(kcondvar_t *, char *, kcv_type_t, void *);
extern void __cv_destroy(kcondvar_t *);
extern void __cv_wait(kcondvar_t *, kmutex_t *);
extern void __cv_wait_io(kcondvar_t *, kmutex_t *);
extern int __cv_wait_io_sig(kcondvar_t *, kmutex_t *);
extern int __cv_wait_sig(kcondvar_t *, kmutex_t *);
extern int __cv_timedwait(kcondvar_t *, kmutex_t *, clock_t);
extern int __cv_timedwait_io(kcondvar_t *, kmutex_t *, clock_t);
extern int __cv_timedwait_sig(kcondvar_t *, kmutex_t *, clock_t);
extern int cv_timedwait_hires(kcondvar_t *, kmutex_t *, hrtime_t,
hrtime_t res, int flag);
extern int cv_timedwait_sig_hires(kcondvar_t *, kmutex_t *, hrtime_t,
hrtime_t res, int flag);
extern void __cv_signal(kcondvar_t *);
extern void __cv_broadcast(kcondvar_t *c);
#define cv_init(cvp, name, type, arg) __cv_init(cvp, name, type, arg)
#define cv_destroy(cvp) __cv_destroy(cvp)
#define cv_wait(cvp, mp) __cv_wait(cvp, mp)
#define cv_wait_io(cvp, mp) __cv_wait_io(cvp, mp)
#define cv_wait_io_sig(cvp, mp) __cv_wait_io_sig(cvp, mp)
#define cv_wait_sig(cvp, mp) __cv_wait_sig(cvp, mp)
#define cv_signal(cvp) __cv_signal(cvp)
#define cv_broadcast(cvp) __cv_broadcast(cvp)
/*
* NB: There is no way to reliably distinguish between having been signalled
* and having timed out on Linux. If the client code needs to reliably
* distinguish between the two it should use the hires variant.
*/
#define cv_timedwait(cvp, mp, t) __cv_timedwait(cvp, mp, t)
#define cv_timedwait_io(cvp, mp, t) __cv_timedwait_io(cvp, mp, t)
#define cv_timedwait_sig(cvp, mp, t) __cv_timedwait_sig(cvp, mp, t)
#endif /* _SPL_CONDVAR_H */
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