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  * $FreeBSD$
30  */
31 #ifndef	_LINUX_SPINLOCK_H_
32 #define	_LINUX_SPINLOCK_H_
33 
34 #include <sys/param.h>
35 #include <sys/kernel.h>
36 #include <sys/lock.h>
37 #include <sys/mutex.h>
38 #include <sys/kdb.h>
39 
40 #include <linux/compiler.h>
41 #include <linux/rwlock.h>
42 #include <linux/bottom_half.h>
43 
44 typedef struct {
45 	struct mtx m;
46 } spinlock_t;
47 
48 /*
49  * By defining CONFIG_SPIN_SKIP LinuxKPI spinlocks and asserts will be
50  * skipped during panic(). By default it is disabled due to
51  * performance reasons.
52  */
53 #ifdef CONFIG_SPIN_SKIP
54 #define	SPIN_SKIP(void)	unlikely(SCHEDULER_STOPPED() || kdb_active)
55 #else
56 #define	SPIN_SKIP(void) 0
57 #endif
58 
59 #define	spin_lock(_l) do {			\
60 	if (SPIN_SKIP())			\
61 		break;				\
62 	mtx_lock(&(_l)->m);			\
63 	local_bh_disable();			\
64 } while (0)
65 
66 #define	spin_lock_bh(_l) do {			\
67 	spin_lock(_l);				\
68 } while (0)
69 
70 #define	spin_lock_irq(_l) do {			\
71 	spin_lock(_l);				\
72 } while (0)
73 
74 #define	spin_unlock(_l)	do {			\
75 	if (SPIN_SKIP())			\
76 		break;				\
77 	local_bh_enable();			\
78 	mtx_unlock(&(_l)->m);			\
79 } while (0)
80 
81 #define	spin_unlock_bh(_l) do {			\
82 	spin_unlock(_l);			\
83 } while (0)
84 
85 #define	spin_unlock_irq(_l) do {		\
86 	spin_unlock(_l);			\
87 } while (0)
88 
89 #define	spin_trylock(_l) ({			\
90 	int __ret;				\
91 	if (SPIN_SKIP()) {			\
92 		__ret = 1;			\
93 	} else {				\
94 		__ret = mtx_trylock(&(_l)->m);	\
95 		if (likely(__ret != 0))		\
96 			local_bh_disable();	\
97 	}					\
98 	__ret;					\
99 })
100 
101 #define	spin_lock_nested(_l, _n) do {		\
102 	if (SPIN_SKIP())			\
103 		break;				\
104 	mtx_lock_flags(&(_l)->m, MTX_DUPOK);	\
105 	local_bh_disable();			\
106 } while (0)
107 
108 #define	spin_lock_irqsave(_l, flags) do {	\
109 	(flags) = 0;				\
110 	spin_lock(_l);				\
111 } while (0)
112 
113 #define	spin_lock_irqsave_nested(_l, flags, _n) do {	\
114 	(flags) = 0;					\
115 	spin_lock_nested(_l, _n);			\
116 } while (0)
117 
118 #define	spin_unlock_irqrestore(_l, flags) do {		\
119 	spin_unlock(_l);				\
120 } while (0)
121 
122 #ifdef WITNESS_ALL
123 /* NOTE: the maximum WITNESS name is 64 chars */
124 #define	__spin_lock_name(name, file, line)		\
125 	(((const char *){file ":" #line "-" name}) + 	\
126 	(sizeof(file) > 16 ? sizeof(file) - 16 : 0))
127 #else
128 #define	__spin_lock_name(name, file, line)	name
129 #endif
130 #define	_spin_lock_name(...)		__spin_lock_name(__VA_ARGS__)
131 #define	spin_lock_name(name)		_spin_lock_name(name, __FILE__, __LINE__)
132 
133 #define	spin_lock_init(lock)	linux_spin_lock_init(lock, spin_lock_name("lnxspin"))
134 
135 static inline void
136 linux_spin_lock_init(spinlock_t *lock, const char *name)
137 {
138 
139 	memset(lock, 0, sizeof(*lock));
140 	mtx_init(&lock->m, name, NULL, MTX_DEF | MTX_NOWITNESS);
141 }
142 
143 static inline void
144 spin_lock_destroy(spinlock_t *lock)
145 {
146 
147        mtx_destroy(&lock->m);
148 }
149 
150 #define	DEFINE_SPINLOCK(lock)					\
151 	spinlock_t lock;					\
152 	MTX_SYSINIT(lock, &(lock).m, spin_lock_name("lnxspin"), MTX_DEF)
153 
154 #define	assert_spin_locked(_l) do {		\
155 	if (SPIN_SKIP())			\
156 		break;				\
157 	mtx_assert(&(_l)->m, MA_OWNED);		\
158 } while (0)
159 
160 #endif					/* _LINUX_SPINLOCK_H_ */
161