include/os/freebsd/spl/sys/rwlock.h

   1 /*
   2  * Copyright (c) 2007 Pawel Jakub Dawidek <pjd@FreeBSD.org>
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  *
  14  * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
  15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
  18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  24  * SUCH DAMAGE.
  25  *
  26  * $FreeBSD$
  27  */
  28
  29 #ifndef _OPENSOLARIS_SYS_RWLOCK_H_
  30 #define _OPENSOLARIS_SYS_RWLOCK_H_
  31
  32 #include <sys/param.h>
  33 #include <sys/proc.h>
  34 #include <sys/lock.h>
  35 #include <sys/sx.h>
  36
  37 typedef enum {
  38         RW_DEFAULT = 4          /* kernel default rwlock */
  39 } krw_type_t;
  40
  41
  42 typedef enum {
  43         RW_NONE         = 0,
  44         RW_WRITER       = 1,
  45         RW_READER       = 2
  46 } krw_t;
  47
  48 typedef struct sx       krwlock_t;
  49
  50 #ifndef OPENSOLARIS_WITNESS
  51 #define RW_FLAGS        (SX_DUPOK | SX_NEW | SX_NOWITNESS)
  52 #else
  53 #define RW_FLAGS        (SX_DUPOK | SX_NEW)
  54 #endif
  55
  56 #define RW_READ_HELD(x)         (rw_read_held((x)))
  57 #define RW_WRITE_HELD(x)        (rw_write_held((x)))
  58 #define RW_LOCK_HELD(x)         (rw_lock_held((x)))
  59 #define RW_ISWRITER(x)          (rw_iswriter(x))
  60 #define rw_init(lock, desc, type, arg)  do {                            \
  61         const char *_name;                                              \
  62         ASSERT((type) == 0 || (type) == RW_DEFAULT);                    \
  63         for (_name = #lock; *_name != '\0'; _name++) {                  \
  64                 if (*_name >= 'a' && *_name <= 'z')                     \
  65                         break;                                          \
  66         }                                                               \
  67         if (*_name == '\0')                                             \
  68                 _name = #lock;                                          \
  69         sx_init_flags((lock), _name, RW_FLAGS);                         \
  70 } while (0)
  71 #define rw_destroy(lock)        sx_destroy(lock)
  72 #define rw_enter(lock, how)     do {                                    \
  73         if ((how) == RW_READER)                                         \
  74                 sx_slock(lock);                                         \
  75         else /* if ((how) == RW_WRITER) */                              \
  76                 sx_xlock(lock);                                         \
  77         } while (0)
  78
  79 #define rw_tryenter(lock, how)                     \
  80         ((how) == RW_READER ? sx_try_slock(lock) : sx_try_xlock(lock))
  81 #define rw_exit(lock)           sx_unlock(lock)
  82 #define rw_downgrade(lock)      sx_downgrade(lock)
  83 #define rw_tryupgrade(lock)     sx_try_upgrade(lock)
  84 #define rw_read_held(lock)                                        \
  85         ((lock)->sx_lock != SX_LOCK_UNLOCKED &&   \
  86             ((lock)->sx_lock & SX_LOCK_SHARED))
  87 #define rw_write_held(lock)     sx_xlocked(lock)
  88 #define rw_lock_held(lock)      (rw_read_held(lock) || rw_write_held(lock))
  89 #define rw_iswriter(lock)       sx_xlocked(lock)
  90 #define rw_owner(lock)          sx_xholder(lock)
  91
  92 #endif  /* _OPENSOLARIS_SYS_RWLOCK_H_ */