mutex.h revision 329955 
1/*-
2 * Copyright (c) 2010 Isilon Systems, Inc.
3 * Copyright (c) 2010 iX Systems, Inc.
4 * Copyright (c) 2010 Panasas, Inc.
5 * Copyright (c) 2013-2017 Mellanox Technologies, Ltd.
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice unmodified, this list of conditions, and the following
13 *    disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 *    notice, this list of conditions and the following disclaimer in the
16 *    documentation and/or other materials provided with the distribution.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
19 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
20 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
21 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
22 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
23 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
24 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
25 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
26 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
27 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28 *
29 * $FreeBSD: stable/11/sys/compat/linuxkpi/common/include/linux/mutex.h 329955 2018-02-25 10:19:44Z hselasky $
30 */
31#ifndef	_LINUX_MUTEX_H_
32#define	_LINUX_MUTEX_H_
33
34#include <sys/param.h>
35#include <sys/proc.h>
36#include <sys/lock.h>
37#include <sys/sx.h>
38
39#include <linux/spinlock.h>
40
41typedef struct mutex {
42	struct sx sx;
43} mutex_t;
44
45/*
46 * By defining CONFIG_NO_MUTEX_SKIP LinuxKPI mutexes and asserts will
47 * not be skipped during panic().
48 */
49#ifdef CONFIG_NO_MUTEX_SKIP
50#define	MUTEX_SKIP(void) 0
51#else
52#define	MUTEX_SKIP(void) unlikely(SCHEDULER_STOPPED() || kdb_active)
53#endif
54
55#define	mutex_lock(_m) do {			\
56	if (MUTEX_SKIP())			\
57		break;				\
58	sx_xlock(&(_m)->sx);			\
59} while (0)
60
61#define	mutex_lock_nested(_m, _s)	mutex_lock(_m)
62#define	mutex_lock_nest_lock(_m, _s)	mutex_lock(_m)
63
64#define	mutex_lock_interruptible(_m) ({		\
65	MUTEX_SKIP() ? 0 :			\
66	(sx_xlock_sig(&(_m)->sx) ? -EINTR : 0);	\
67})
68
69#define	mutex_unlock(_m) do {			\
70	if (MUTEX_SKIP())			\
71		break;				\
72	sx_xunlock(&(_m)->sx);			\
73} while (0)
74
75#define	mutex_trylock(_m) ({			\
76	MUTEX_SKIP() ? 1 :			\
77	!!sx_try_xlock(&(_m)->sx);		\
78})
79
80enum mutex_trylock_recursive_enum {
81	MUTEX_TRYLOCK_FAILED = 0,
82	MUTEX_TRYLOCK_SUCCESS = 1,
83	MUTEX_TRYLOCK_RECURSIVE = 2,
84};
85
86static inline __must_check enum mutex_trylock_recursive_enum
87mutex_trylock_recursive(struct mutex *lock)
88{
89	if (unlikely(sx_xholder(&lock->sx) == curthread))
90		return (MUTEX_TRYLOCK_RECURSIVE);
91
92	return (mutex_trylock(lock));
93}
94
95#define	mutex_init(_m) \
96	linux_mutex_init(_m, mutex_name(#_m), SX_NOWITNESS)
97
98#define	mutex_init_witness(_m) \
99	linux_mutex_init(_m, mutex_name(#_m), SX_DUPOK)
100
101#define	mutex_destroy(_m) \
102	linux_mutex_destroy(_m)
103
104static inline bool
105mutex_is_locked(mutex_t *m)
106{
107	return ((struct thread *)SX_OWNER(m->sx.sx_lock) != NULL);
108}
109
110static inline bool
111mutex_is_owned(mutex_t *m)
112{
113	return (sx_xlocked(&m->sx));
114}
115
116#ifdef WITNESS_ALL
117/* NOTE: the maximum WITNESS name is 64 chars */
118#define	__mutex_name(name, file, line)		\
119	(((const char *){file ":" #line "-" name}) + 	\
120	(sizeof(file) > 16 ? sizeof(file) - 16 : 0))
121#else
122#define	__mutex_name(name, file, line)	name
123#endif
124#define	_mutex_name(...)	__mutex_name(__VA_ARGS__)
125#define	mutex_name(name)	_mutex_name(name, __FILE__, __LINE__)
126
127#define	DEFINE_MUTEX(lock)						\
128	mutex_t lock;							\
129	SX_SYSINIT_FLAGS(lock, &(lock).sx, mutex_name(#lock), SX_DUPOK)
130
131static inline void
132linux_mutex_init(mutex_t *m, const char *name, int flags)
133{
134	memset(m, 0, sizeof(*m));
135	sx_init_flags(&m->sx, name, flags);
136}
137
138static inline void
139linux_mutex_destroy(mutex_t *m)
140{
141	if (mutex_is_owned(m))
142		mutex_unlock(m);
143	sx_destroy(&m->sx);
144}
145
146#endif					/* _LINUX_MUTEX_H_ */
147