xref: /illumos-gate/usr/src/lib/libfakekernel/common/mutex.c (revision 1ca4e8df0656724dae6eea0884d84d8d4c1aabb2)
1 /*
2  * This file and its contents are supplied under the terms of the
3  * Common Development and Distribution License ("CDDL"), version 1.0.
4  * You may only use this file in accordance with the terms of version
5  * 1.0 of the CDDL.
6  *
7  * A full copy of the text of the CDDL should have accompanied this
8  * source.  A copy of the CDDL is also available via the Internet at
9  * http://www.illumos.org/license/CDDL.
10  */
11 
12 /*
13  * Copyright 2018 Nexenta Systems, Inc.  All rights reserved.
14  * Copyright 2017 RackTop Systems.
15  */
16 
17 /*
18  * mutex(9f)
19  */
20 
21 /* This is the API we're emulating */
22 #include <sys/mutex.h>
23 
24 #include <sys/errno.h>
25 #include <sys/debug.h>
26 #include <sys/thread.h>
27 
28 int	_lwp_mutex_lock(lwp_mutex_t *);
29 int	_lwp_mutex_unlock(lwp_mutex_t *);
30 int	_lwp_mutex_trylock(lwp_mutex_t *);
31 
32 extern clock_t ddi_get_lbolt(void);
33 
34 /* See: head/synch.h ERRORCHECKMUTEX */
35 static const lwp_mutex_t default_mutex =
36 	{{0, 0, 0, {USYNC_THREAD|LOCK_ERRORCHECK}, _MUTEX_MAGIC},
37 	{{{0, 0, 0, 0, 0, 0, 0, 0}}}, 0};
38 
39 /* ARGSUSED */
40 void
41 kmutex_init(kmutex_t *mp, char *name, kmutex_type_t typ, void *arg)
42 {
43 	mp->m_lock = default_mutex;
44 	mp->m_owner = _KTHREAD_INVALID;
45 }
46 
47 /* ARGSUSED */
48 void
49 kmutex_destroy(kmutex_t *mp)
50 {
51 	mp->m_owner = _KTHREAD_INVALID;
52 }
53 
54 void
55 kmutex_enter(kmutex_t *mp)
56 {
57 	kthread_t *t = _curthread();
58 
59 	VERIFY(mp->m_owner != t);
60 	VERIFY(0 == _lwp_mutex_lock(&mp->m_lock));
61 	mp->m_owner = t;
62 }
63 
64 int
65 mutex_tryenter(kmutex_t *mp)
66 {
67 	int rc;
68 
69 	rc = _lwp_mutex_trylock(&mp->m_lock);
70 	if (rc == 0) {
71 		mp->m_owner = _curthread();
72 		return (1);
73 	}
74 	return (0);
75 }
76 
77 void
78 kmutex_exit(kmutex_t *mp)
79 {
80 	ASSERT(mp->m_owner == _curthread());
81 	mp->m_owner = _KTHREAD_INVALID;
82 	(void) _lwp_mutex_unlock(&mp->m_lock);
83 }
84 
85 /*
86  * Returns the kthread_t * of the owner.
87  */
88 void *
89 mutex_owner(const kmutex_t *mp)
90 {
91 	return (mp->m_owner);
92 }
93 
94 int
95 mutex_owned(const kmutex_t *mp)
96 {
97 	void *t = _curthread();
98 	return (t == mp->m_owner);
99 }
100