xref: /titanic_50/usr/src/uts/common/sys/waitq.h (revision c97ad5cdc75eb73e3cc38542ca3ba783574b0a7a)
1*c97ad5cdSakolb /*
2*c97ad5cdSakolb  * CDDL HEADER START
3*c97ad5cdSakolb  *
4*c97ad5cdSakolb  * The contents of this file are subject to the terms of the
5*c97ad5cdSakolb  * Common Development and Distribution License (the "License").
6*c97ad5cdSakolb  * You may not use this file except in compliance with the License.
7*c97ad5cdSakolb  *
8*c97ad5cdSakolb  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9*c97ad5cdSakolb  * or http://www.opensolaris.org/os/licensing.
10*c97ad5cdSakolb  * See the License for the specific language governing permissions
11*c97ad5cdSakolb  * and limitations under the License.
12*c97ad5cdSakolb  *
13*c97ad5cdSakolb  * When distributing Covered Code, include this CDDL HEADER in each
14*c97ad5cdSakolb  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15*c97ad5cdSakolb  * If applicable, add the following below this CDDL HEADER, with the
16*c97ad5cdSakolb  * fields enclosed by brackets "[]" replaced with your own identifying
17*c97ad5cdSakolb  * information: Portions Copyright [yyyy] [name of copyright owner]
18*c97ad5cdSakolb  *
19*c97ad5cdSakolb  * CDDL HEADER END
20*c97ad5cdSakolb  */
21*c97ad5cdSakolb /*
22*c97ad5cdSakolb  * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
23*c97ad5cdSakolb  * Use is subject to license terms.
24*c97ad5cdSakolb  */
25*c97ad5cdSakolb 
26*c97ad5cdSakolb #ifndef _SYS_WAITQ_H
27*c97ad5cdSakolb #define	_SYS_WAITQ_H
28*c97ad5cdSakolb 
29*c97ad5cdSakolb #pragma ident	"%Z%%M%	%I%	%E% SMI"
30*c97ad5cdSakolb 
31*c97ad5cdSakolb #ifdef	__cplusplus
32*c97ad5cdSakolb extern "C" {
33*c97ad5cdSakolb #endif
34*c97ad5cdSakolb 
35*c97ad5cdSakolb #ifdef	_KERNEL
36*c97ad5cdSakolb 
37*c97ad5cdSakolb #include <sys/types.h>
38*c97ad5cdSakolb #include <sys/machlock.h>
39*c97ad5cdSakolb #include <sys/thread.h>
40*c97ad5cdSakolb 
41*c97ad5cdSakolb typedef struct waitq {
42*c97ad5cdSakolb 	disp_lock_t	wq_lock;	/* protects all fields */
43*c97ad5cdSakolb 	kthread_t	*wq_first;	/* first thread on the queue */
44*c97ad5cdSakolb 	int		wq_count;	/* number of threads on the queue */
45*c97ad5cdSakolb 	boolean_t	wq_blocked;	/* True if threads can't be enqueued */
46*c97ad5cdSakolb } waitq_t;
47*c97ad5cdSakolb 
48*c97ad5cdSakolb extern void		waitq_init(waitq_t *);
49*c97ad5cdSakolb extern void		waitq_fini(waitq_t *);
50*c97ad5cdSakolb 
51*c97ad5cdSakolb /*
52*c97ad5cdSakolb  * Place the thread on the wait queue. An attempt to enqueue a thread onto a
53*c97ad5cdSakolb  * blocked queue fails and returns zero. Successful enqueue returns non-zero
54*c97ad5cdSakolb  * value.
55*c97ad5cdSakolb  */
56*c97ad5cdSakolb extern int		waitq_enqueue(waitq_t *, kthread_t *);
57*c97ad5cdSakolb 
58*c97ad5cdSakolb /*
59*c97ad5cdSakolb  * Take thread off its wait queue and make it runnable.
60*c97ad5cdSakolb  */
61*c97ad5cdSakolb extern void		waitq_setrun(kthread_t *t);
62*c97ad5cdSakolb 
63*c97ad5cdSakolb /*
64*c97ad5cdSakolb  * Change priority for the thread on wait queue.
65*c97ad5cdSakolb  */
66*c97ad5cdSakolb extern void		waitq_change_pri(kthread_t *, pri_t);
67*c97ad5cdSakolb 
68*c97ad5cdSakolb /*
69*c97ad5cdSakolb  * Take the first thread off the wait queue and make it runnable.
70*c97ad5cdSakolb  */
71*c97ad5cdSakolb extern void		waitq_runone(waitq_t *);
72*c97ad5cdSakolb 
73*c97ad5cdSakolb /*
74*c97ad5cdSakolb  * Return True if there are no threads on the queue.
75*c97ad5cdSakolb  */
76*c97ad5cdSakolb extern boolean_t	waitq_isempty(waitq_t *);
77*c97ad5cdSakolb 
78*c97ad5cdSakolb /*
79*c97ad5cdSakolb  * Prevent and allow placing new threads on wait queue.
80*c97ad5cdSakolb  */
81*c97ad5cdSakolb extern void		waitq_block(waitq_t *);
82*c97ad5cdSakolb extern void		waitq_unblock(waitq_t *);
83*c97ad5cdSakolb 
84*c97ad5cdSakolb #endif	/* _KERNEL */
85*c97ad5cdSakolb 
86*c97ad5cdSakolb #ifdef	__cplusplus
87*c97ad5cdSakolb }
88*c97ad5cdSakolb #endif
89*c97ad5cdSakolb 
90*c97ad5cdSakolb #endif	/* _SYS_WAITQ_H */
91