include/os/linux/spl/sys/condvar.h

   1 /*
   2  *  Copyright (C) 2007-2010 Lawrence Livermore National Security, LLC.
   3  *  Copyright (C) 2007 The Regents of the University of California.
   4  *  Produced at Lawrence Livermore National Laboratory (cf, DISCLAIMER).
   5  *  Written by Brian Behlendorf <behlendorf1@llnl.gov>.
   6  *  UCRL-CODE-235197
   7  *
   8  *  This file is part of the SPL, Solaris Porting Layer.
   9  *
  10  *  The SPL is free software; you can redistribute it and/or modify it
  11  *  under the terms of the GNU General Public License as published by the
  12  *  Free Software Foundation; either version 2 of the License, or (at your
  13  *  option) any later version.
  14  *
  15  *  The SPL is distributed in the hope that it will be useful, but WITHOUT
  16  *  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  17  *  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  18  *  for more details.
  19  *
  20  *  You should have received a copy of the GNU General Public License along
  21  *  with the SPL.  If not, see <http://www.gnu.org/licenses/>.
  22  */
  23
  24 #ifndef _SPL_CONDVAR_H
  25 #define _SPL_CONDVAR_H
  26
  27 #include <linux/module.h>
  28 #include <sys/kmem.h>
  29 #include <sys/mutex.h>
  30 #include <sys/callo.h>
  31 #include <sys/wait.h>
  32 #include <sys/time.h>
  33
  34 /*
  35  * cv_timedwait() is similar to cv_wait() except that it additionally expects
  36  * a timeout value specified in ticks.  When woken by cv_signal() or
  37  * cv_broadcast() it returns 1, otherwise when the timeout is reached -1 is
  38  * returned.
  39  *
  40  * cv_timedwait_sig() behaves the same as cv_timedwait() but blocks
  41  * interruptibly and can be woken by a signal (EINTR, ERESTART).  When
  42  * this occurs 0 is returned.
  43  *
  44  * cv_timedwait_io() and cv_timedwait_sig_io() are variants of cv_timedwait()
  45  * and cv_timedwait_sig() which should be used when waiting for outstanding
  46  * IO to complete.  They are responsible for updating the iowait accounting
  47  * when this is supported by the platform.
  48  *
  49  * cv_timedwait_hires() and cv_timedwait_sig_hires() are high resolution
  50  * versions of cv_timedwait() and cv_timedwait_sig().  They expect the timeout
  51  * to be specified as a hrtime_t allowing for timeouts of less than a tick.
  52  *
  53  * N.B. The return values differ slightly from the illumos implementation
  54  * which returns the time remaining, instead of 1, when woken.  They both
  55  * return -1 on timeout. Consumers which need to know the time remaining
  56  * are responsible for tracking it themselves.
  57  */
  58
  59
  60 /*
  61  * The kcondvar_t struct is protected by mutex taken externally before
  62  * calling any of the wait/signal funs, and passed into the wait funs.
  63  */
  64 #define CV_MAGIC                        0x346545f4
  65 #define CV_DESTROY                      0x346545f5
  66
  67 typedef struct {
  68         int cv_magic;
  69         wait_queue_head_t cv_event;
  70         wait_queue_head_t cv_destroy;
  71         atomic_t cv_refs;
  72         atomic_t cv_waiters;
  73         kmutex_t *cv_mutex;
  74 } kcondvar_t;
  75
  76 typedef enum { CV_DEFAULT = 0, CV_DRIVER } kcv_type_t;
  77
  78 extern void __cv_init(kcondvar_t *, char *, kcv_type_t, void *);
  79 extern void __cv_destroy(kcondvar_t *);
  80 extern void __cv_wait(kcondvar_t *, kmutex_t *);
  81 extern void __cv_wait_io(kcondvar_t *, kmutex_t *);
  82 extern void __cv_wait_idle(kcondvar_t *, kmutex_t *);
  83 extern int __cv_wait_io_sig(kcondvar_t *, kmutex_t *);
  84 extern int __cv_wait_sig(kcondvar_t *, kmutex_t *);
  85 extern int __cv_timedwait(kcondvar_t *, kmutex_t *, clock_t);
  86 extern int __cv_timedwait_io(kcondvar_t *, kmutex_t *, clock_t);
  87 extern int __cv_timedwait_sig(kcondvar_t *, kmutex_t *, clock_t);
  88 extern int __cv_timedwait_idle(kcondvar_t *, kmutex_t *, clock_t);
  89 extern int cv_timedwait_hires(kcondvar_t *, kmutex_t *, hrtime_t,
  90     hrtime_t res, int flag);
  91 extern int cv_timedwait_sig_hires(kcondvar_t *, kmutex_t *, hrtime_t,
  92     hrtime_t res, int flag);
  93 extern int cv_timedwait_idle_hires(kcondvar_t *, kmutex_t *, hrtime_t,
  94     hrtime_t res, int flag);
  95 extern void __cv_signal(kcondvar_t *);
  96 extern void __cv_broadcast(kcondvar_t *c);
  97
  98 #define cv_init(cvp, name, type, arg)           __cv_init(cvp, name, type, arg)
  99 #define cv_destroy(cvp)                         __cv_destroy(cvp)
 100 #define cv_wait(cvp, mp)                        __cv_wait(cvp, mp)
 101 #define cv_wait_io(cvp, mp)                     __cv_wait_io(cvp, mp)
 102 #define cv_wait_idle(cvp, mp)                   __cv_wait_idle(cvp, mp)
 103 #define cv_wait_io_sig(cvp, mp)                 __cv_wait_io_sig(cvp, mp)
 104 #define cv_wait_sig(cvp, mp)                    __cv_wait_sig(cvp, mp)
 105 #define cv_signal(cvp)                          __cv_signal(cvp)
 106 #define cv_broadcast(cvp)                       __cv_broadcast(cvp)
 107
 108 /*
 109  * NB: There is no way to reliably distinguish between having been signalled
 110  * and having timed out on Linux. If the client code needs to reliably
 111  * distinguish between the two it should use the hires variant.
 112  */
 113 #define cv_timedwait(cvp, mp, t)                __cv_timedwait(cvp, mp, t)
 114 #define cv_timedwait_io(cvp, mp, t)             __cv_timedwait_io(cvp, mp, t)
 115 #define cv_timedwait_sig(cvp, mp, t)            __cv_timedwait_sig(cvp, mp, t)
 116 #define cv_timedwait_idle(cvp, mp, t)           __cv_timedwait_idle(cvp, mp, t)
 117
 118
 119 #endif /* _SPL_CONDVAR_H */