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 #ifndef _LINUXKPI_LINUX_SPINLOCK_H_
30 #define _LINUXKPI_LINUX_SPINLOCK_H_
31
32 #include <asm/atomic.h>
33 #include <sys/param.h>
34 #include <sys/kernel.h>
35 #include <sys/lock.h>
36 #include <sys/mutex.h>
37 #include <sys/kdb.h>
38
39 #include <linux/compiler.h>
40 #include <linux/rwlock.h>
41 #include <linux/bottom_half.h>
42 #include <linux/lockdep.h>
43
44 typedef struct mtx spinlock_t;
45
46 /*
47 * By defining CONFIG_SPIN_SKIP LinuxKPI spinlocks and asserts will be
48 * skipped during panic(). By default it is disabled due to
49 * performance reasons.
50 */
51 #ifdef CONFIG_SPIN_SKIP
52 #define SPIN_SKIP(void) unlikely(SCHEDULER_STOPPED() || kdb_active)
53 #else
54 #define SPIN_SKIP(void) 0
55 #endif
56
57 #define spin_lock(_l) do { \
58 if (SPIN_SKIP()) \
59 break; \
60 mtx_lock(_l); \
61 local_bh_disable(); \
62 } while (0)
63
64 #define spin_lock_bh(_l) do { \
65 spin_lock(_l); \
66 local_bh_disable(); \
67 } while (0)
68
69 #define spin_lock_irq(_l) do { \
70 spin_lock(_l); \
71 } while (0)
72
73 #define spin_unlock(_l) do { \
74 if (SPIN_SKIP()) \
75 break; \
76 local_bh_enable(); \
77 mtx_unlock(_l); \
78 } while (0)
79
80 #define spin_unlock_bh(_l) do { \
81 local_bh_enable(); \
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); \
95 if (likely(__ret != 0)) \
96 local_bh_disable(); \
97 } \
98 __ret; \
99 })
100
101 #define spin_trylock_irq(_l) \
102 spin_trylock(_l)
103
104 #define spin_trylock_irqsave(_l, flags) ({ \
105 (flags) = 0; \
106 spin_trylock(_l); \
107 })
108
109 #define spin_lock_nested(_l, _n) do { \
110 if (SPIN_SKIP()) \
111 break; \
112 mtx_lock_flags(_l, MTX_DUPOK); \
113 local_bh_disable(); \
114 } while (0)
115
116 #define spin_lock_irqsave(_l, flags) do { \
117 (flags) = 0; \
118 spin_lock(_l); \
119 } while (0)
120
121 #define spin_lock_irqsave_nested(_l, flags, _n) do { \
122 (flags) = 0; \
123 spin_lock_nested(_l, _n); \
124 } while (0)
125
126 #define spin_unlock_irqrestore(_l, flags) do { \
127 (void)(flags); \
128 spin_unlock(_l); \
129 } while (0)
130
131 #ifdef WITNESS_ALL
132 /* NOTE: the maximum WITNESS name is 64 chars */
133 #define __spin_lock_name(name, file, line) \
134 (((const char *){file ":" #line "-" name}) + \
135 (sizeof(file) > 16 ? sizeof(file) - 16 : 0))
136 #else
137 #define __spin_lock_name(name, file, line) name
138 #endif
139 #define _spin_lock_name(...) __spin_lock_name(__VA_ARGS__)
140 #define spin_lock_name(name) _spin_lock_name(name, __FILE__, __LINE__)
141
142 #define spin_lock_init(lock) mtx_init(lock, spin_lock_name("lnxspin"), \
143 NULL, MTX_DEF | MTX_NOWITNESS | MTX_NEW)
144
145 #define spin_lock_destroy(_l) mtx_destroy(_l)
146
147 #define DEFINE_SPINLOCK(lock) \
148 spinlock_t lock; \
149 MTX_SYSINIT(lock, &lock, spin_lock_name("lnxspin"), MTX_DEF)
150
151 #define assert_spin_locked(_l) do { \
152 if (SPIN_SKIP()) \
153 break; \
154 mtx_assert(_l, MA_OWNED); \
155 } while (0)
156
157 #define atomic_dec_and_lock_irqsave(cnt, lock, flags) \
158 _atomic_dec_and_lock_irqsave(cnt, lock, &(flags))
159 static inline int
_atomic_dec_and_lock_irqsave(atomic_t * cnt,spinlock_t * lock,unsigned long * flags)160 _atomic_dec_and_lock_irqsave(atomic_t *cnt, spinlock_t *lock,
161 unsigned long *flags)
162 {
163 if (atomic_add_unless(cnt, -1, 1))
164 return (0);
165
166 spin_lock_irqsave(lock, *flags);
167 if (atomic_dec_and_test(cnt))
168 return (1);
169 spin_unlock_irqrestore(lock, *flags);
170 return (0);
171 }
172
173 #endif /* _LINUXKPI_LINUX_SPINLOCK_H_ */
174