sys/cddl/compat/opensolaris/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 #ifdef _KERNEL
  38
  39 typedef enum {
  40         RW_DEFAULT = 4          /* kernel default rwlock */
  41 } krw_type_t;
  42
  43 typedef enum {
  44         RW_WRITER,
  45         RW_READER
  46 } krw_t;
  47
  48 typedef struct sx       krwlock_t;
  49
  50 #ifndef OPENSOLARIS_WITNESS
  51 #define RW_FLAGS        (SX_DUPOK | SX_NOWITNESS)
  52 #else
  53 #define RW_FLAGS        (SX_DUPOK)
  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
  61 #define rw_init(lock, desc, type, arg)  do {                            \
  62         const char *_name;                                              \
  63         ASSERT((type) == 0 || (type) == RW_DEFAULT);                    \
  64         KASSERT(((lock)->lock_object.lo_flags & LO_ALLMASK) !=          \
  65             LO_EXPECTED, ("lock %s already initialized", #lock));       \
  66         bzero((lock), sizeof(struct sx));                               \
  67         for (_name = #lock; *_name != '\0'; _name++) {                  \
  68                 if (*_name >= 'a' && *_name <= 'z')                     \
  69                         break;                                          \
  70         }                                                               \
  71         if (*_name == '\0')                                             \
  72                 _name = #lock;                                          \
  73         sx_init_flags((lock), _name, RW_FLAGS);                         \
  74 } while (0)
  75 #define rw_destroy(lock)        sx_destroy(lock)
  76 #define rw_enter(lock, how)     do {                                    \
  77         if ((how) == RW_READER)                                         \
  78                 sx_slock(lock);                                         \
  79         else /* if ((how) == RW_WRITER) */                              \
  80                 sx_xlock(lock);                                         \
  81 } while (0)
  82 #define rw_tryenter(lock, how)  ((how) == RW_READER ? sx_try_slock(lock) : sx_try_xlock(lock))
  83 #define rw_exit(lock)           sx_unlock(lock)
  84 #define rw_downgrade(lock)      sx_downgrade(lock)
  85 #define rw_tryupgrade(lock)     sx_try_upgrade(lock)
  86 #define rw_read_held(lock)      ((lock)->sx_lock != SX_LOCK_UNLOCKED && ((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 /* TODO: Change to sx_xholder() once it is moved from kern_sx.c to sx.h. */
  91 #define rw_owner(lock)          ((lock)->sx_lock & SX_LOCK_SHARED ? NULL : (struct thread *)SX_OWNER((lock)->sx_lock))
  92
  93 #endif  /* defined(_KERNEL) */
  94
  95 #endif  /* _OPENSOLARIS_SYS_RWLOCK_H_ */