usr/src/uts/common/sys/rwstlock.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, Version 1.0 only
   6  * (the "License").  You may not use this file except in compliance
   7  * with the License.
   8  *
   9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
  10  * or http://www.opensolaris.org/os/licensing.
  11  * See the License for the specific language governing permissions
  12  * and limitations under the License.
  13  *
  14  * When distributing Covered Code, include this CDDL HEADER in each
  15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  16  * If applicable, add the following below this CDDL HEADER, with the
  17  * fields enclosed by brackets "[]" replaced with your own identifying
  18  * information: Portions Copyright [yyyy] [name of copyright owner]
  19  *
  20  * CDDL HEADER END
  21  */
  22 /*
  23  * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
  24  * Use is subject to license terms.
  25  */
  26
  27 #ifndef _SYS_RWSTLOCK_H
  28 #define _SYS_RWSTLOCK_H
  29
  30 #pragma ident   "%Z%%M% %I%     %E% SMI"
  31
  32 /*
  33  * Alternate rwlock that is interruptible and can be released by a thread
  34  * other than the one that acquired the lock.
  35  */
  36
  37 #ifdef __cplusplus
  38 extern "C" {
  39 #endif
  40
  41 #include <sys/types.h>
  42 #include <sys/ksynch.h>
  43 #include <sys/rwlock.h>
  44
  45 typedef struct rwstlock {
  46         intptr_t        rwst_count;
  47         kcondvar_t      rwst_rcv;
  48         kcondvar_t      rwst_wcv;
  49         kmutex_t        rwst_lock;
  50 } rwstlock_t;
  51
  52 /*
  53  * The interfaces below are private to Sun Microsystems,
  54  * and these might change without notice.
  55  */
  56
  57 #define RWST_TRYENTER   0x01
  58 #define RWST_SIG        0x02
  59
  60 #define RWST_HELD(l)            ((l)->rwst_count != 0)
  61 #define RWST_READ_HELD(l)       ((l)->rwst_count > 0)
  62 #define RWST_WRITE_HELD(l)      ((l)->rwst_count < 0)
  63 #define RWST_WRITE_OWNER(l)     \
  64         ((l)->rwst_count == (LONG_MIN | (intptr_t)curthread))
  65 #define RWST_OWNER(l)           (RWST_WRITE_HELD(l) ? \
  66         ((struct _kthread *)((l)->rwst_count & ~LONG_MIN)) : NULL)
  67 #define RWST_READ_WANTED(l)     CV_HAS_WAITERS(&(l)->rwst_rcv)
  68 #define RWST_WRITE_WANTED(l)    CV_HAS_WAITERS(&(l)->rwst_wcv)
  69 #define RWST_WAIT(cv, lock, f)  \
  70         ((f) & RWST_SIG ? cv_wait_sig(cv, lock) : (cv_wait(cv, lock), 1))
  71 #define RWST_READ_WAIT(l, f)    RWST_WAIT(&(l)->rwst_rcv, &(l)->rwst_lock, f)
  72 #define RWST_WRITE_WAIT(l, f)   RWST_WAIT(&(l)->rwst_wcv, &(l)->rwst_lock, f)
  73 #define RWST_READ_WAKE_ALL(l)   cv_broadcast(&(l)->rwst_rcv)
  74 #define RWST_WRITE_WAKE_ONE(l)  cv_signal(&(l)->rwst_wcv)
  75 #define RWST_READ_ENTER(l)      (l)->rwst_count++
  76 #define RWST_WRITE_ENTER(l)     (l)->rwst_count = LONG_MIN | (intptr_t)curthread
  77 #define RWST_READ_EXIT(l)       (l)->rwst_count--
  78 #define RWST_WRITE_EXIT(l)      (l)->rwst_count = 0
  79
  80 extern void rwst_enter(rwstlock_t *, krw_t);
  81 extern int rwst_enter_sig(rwstlock_t *, krw_t);
  82 extern void rwst_exit(rwstlock_t *);
  83 extern void rwst_init(rwstlock_t *, char *, krw_type_t, void *);
  84 extern void rwst_destroy(rwstlock_t *);
  85 extern int rwst_lock_held(rwstlock_t *, krw_t);
  86 extern int rwst_tryenter(rwstlock_t *, krw_t);
  87 extern struct _kthread *rwst_owner(rwstlock_t *);
  88
  89 #ifdef __cplusplus
  90 }
  91 #endif
  92
  93 #endif /* _SYS_RWSTLOCK_H */