usr/src/uts/common/sys/waitq.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 2007 Sun Microsystems, Inc.  All rights reserved.
  23  * Use is subject to license terms.
  24  */
  25
  26 #ifndef _SYS_WAITQ_H
  27 #define _SYS_WAITQ_H
  28
  29 #ifdef  __cplusplus
  30 extern "C" {
  31 #endif
  32
  33 #ifdef  _KERNEL
  34
  35 #include <sys/types.h>
  36 #include <sys/machlock.h>
  37 #include <sys/thread.h>
  38
  39 typedef struct waitq {
  40         disp_lock_t     wq_lock;        /* protects all fields */
  41         kthread_t       *wq_first;      /* first thread on the queue */
  42         int             wq_count;       /* number of threads on the queue */
  43         boolean_t       wq_blocked;     /* True if threads can't be enqueued */
  44 } waitq_t;
  45
  46 extern void             waitq_init(waitq_t *);
  47 extern void             waitq_fini(waitq_t *);
  48
  49 /*
  50  * Place the thread on the wait queue. An attempt to enqueue a thread onto a
  51  * blocked queue fails and returns zero. Successful enqueue returns non-zero
  52  * value.
  53  */
  54 extern int              waitq_enqueue(waitq_t *, kthread_t *);
  55
  56 /*
  57  * Take thread off its wait queue and make it runnable.
  58  */
  59 extern void             waitq_setrun(kthread_t *t);
  60
  61 /*
  62  * Change priority for the thread on wait queue.
  63  */
  64 extern void             waitq_change_pri(kthread_t *, pri_t);
  65
  66 /*
  67  * Take the first thread off the wait queue and make it runnable.
  68  */
  69 extern void             waitq_runone(waitq_t *);
  70
  71 /*
  72  * Return True if there are no threads on the queue.
  73  */
  74 extern boolean_t        waitq_isempty(waitq_t *);
  75
  76 /*
  77  * Prevent and allow placing new threads on wait queue.
  78  */
  79 extern void             waitq_block(waitq_t *);
  80 extern void             waitq_unblock(waitq_t *);
  81
  82 #endif  /* _KERNEL */
  83
  84 #ifdef  __cplusplus
  85 }
  86 #endif
  87
  88 #endif  /* _SYS_WAITQ_H */