FreeBSD/Linux Kernel Cross Reference
sys/contrib/openzfs/include/os/linux/spl/sys/condvar.h

     /*
      *  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.
      *
     *  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 void __cv_wait_idle(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_idle(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 int cv_timedwait_idle_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_idle(cvp, mp)                   __cv_wait_idle(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)
   #define cv_timedwait_idle(cvp, mp, t)           __cv_timedwait_idle(cvp, mp, t)
   
   
   #endif /* _SPL_CONDVAR_H */

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