usr/src/uts/common/sys/rwlock.h

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or http://www.opensolaris.org/os/licensing.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21 /*
  22  * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
  23  * Use is subject to license terms.
  24  */
  25
  26 /*
  27  * Copyright (c) 2013, Joyent, Inc.  All rights reserved.
  28  */
  29
  30 #ifndef _SYS_RWLOCK_H
  31 #define _SYS_RWLOCK_H
  32
  33 /*
  34  * Public interface to readers/writer locks.  See rwlock(9F) for details.
  35  */
  36
  37 #include <sys/types.h>
  38
  39 #ifdef  __cplusplus
  40 extern "C" {
  41 #endif
  42
  43 #ifndef _ASM
  44
  45 typedef enum {
  46         RW_DRIVER = 2,          /* driver (DDI) rwlock */
  47         RW_DEFAULT = 4          /* kernel default rwlock */
  48 } krw_type_t;
  49
  50 typedef enum {
  51         RW_WRITER,
  52         RW_READER,
  53         RW_READER_STARVEWRITER
  54 } krw_t;
  55
  56 typedef struct _krwlock {
  57         void    *_opaque[1];
  58 } krwlock_t;
  59
  60 #if defined(_KERNEL)
  61
  62 #define RW_READ_HELD(x)         (rw_read_held((x)))
  63 #define RW_WRITE_HELD(x)        (rw_write_held((x)))
  64 #define RW_LOCK_HELD(x)         (rw_lock_held((x)))
  65 #define RW_ISWRITER(x)          (rw_iswriter(x))
  66
  67 extern  void    rw_init(krwlock_t *, char *, krw_type_t, void *);
  68 extern  void    rw_destroy(krwlock_t *);
  69 extern  void    rw_enter(krwlock_t *, krw_t);
  70 extern  int     rw_tryenter(krwlock_t *, krw_t);
  71 extern  void    rw_exit(krwlock_t *);
  72 extern  void    rw_downgrade(krwlock_t *);
  73 extern  int     rw_tryupgrade(krwlock_t *);
  74 extern  int     rw_read_held(krwlock_t *);
  75 extern  int     rw_write_held(krwlock_t *);
  76 extern  int     rw_lock_held(krwlock_t *);
  77 extern  int     rw_read_locked(krwlock_t *);
  78 extern  int     rw_iswriter(krwlock_t *);
  79 extern  struct _kthread *rw_owner(krwlock_t *);
  80 extern  uint_t (*rw_lock_backoff)(uint_t);
  81 extern  void (*rw_lock_delay)(uint_t);
  82
  83 #endif  /* defined(_KERNEL) */
  84
  85 #endif  /* _ASM */
  86
  87 #ifdef  __cplusplus
  88 }
  89 #endif
  90
  91 #endif  /* _SYS_RWLOCK_H */