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 #ifndef _SYS_RWLOCK_H
  27 #define _SYS_RWLOCK_H
  28
  29 #pragma ident   "%Z%%M% %I%     %E% SMI"
  30
  31 /*
  32  * Public interface to readers/writer locks.  See rwlock(9F) for details.
  33  */
  34
  35 #include <sys/types.h>
  36
  37 #ifdef  __cplusplus
  38 extern "C" {
  39 #endif
  40
  41 #ifndef _ASM
  42
  43 typedef enum {
  44         RW_DRIVER = 2,          /* driver (DDI) rwlock */
  45         RW_DEFAULT = 4          /* kernel default rwlock */
  46 } krw_type_t;
  47
  48 typedef enum {
  49         RW_WRITER,
  50         RW_READER
  51 } krw_t;
  52
  53 typedef struct _krwlock {
  54         void    *_opaque[1];
  55 } krwlock_t;
  56
  57 #if defined(_KERNEL)
  58
  59 #define RW_READ_HELD(x)         (rw_read_held((x)))
  60 #define RW_WRITE_HELD(x)        (rw_write_held((x)))
  61 #define RW_LOCK_HELD(x)         (rw_lock_held((x)))
  62 #define RW_ISWRITER(x)          (rw_iswriter(x))
  63
  64 extern  void    rw_init(krwlock_t *, char *, krw_type_t, void *);
  65 extern  void    rw_destroy(krwlock_t *);
  66 extern  void    rw_enter(krwlock_t *, krw_t);
  67 extern  int     rw_tryenter(krwlock_t *, krw_t);
  68 extern  void    rw_exit(krwlock_t *);
  69 extern  void    rw_downgrade(krwlock_t *);
  70 extern  int     rw_tryupgrade(krwlock_t *);
  71 extern  int     rw_read_held(krwlock_t *);
  72 extern  int     rw_write_held(krwlock_t *);
  73 extern  int     rw_lock_held(krwlock_t *);
  74 extern  int     rw_read_locked(krwlock_t *);
  75 extern  int     rw_iswriter(krwlock_t *);
  76 extern  struct _kthread *rw_owner(krwlock_t *);
  77 extern  uint_t (*rw_lock_backoff)(uint_t);
  78 extern  void (*rw_lock_delay)(uint_t);
  79
  80 #endif  /* defined(_KERNEL) */
  81
  82 #endif  /* _ASM */
  83
  84 #ifdef  __cplusplus
  85 }
  86 #endif
  87
  88 #endif  /* _SYS_RWLOCK_H */