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/cleanup.h>
40 #include <linux/compiler.h>
41 #include <linux/rwlock.h>
42 #include <linux/bottom_half.h>
43 #include <linux/lockdep.h>
44 #include <linux/preempt.h>
45
46 typedef struct mtx 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); \
63 local_bh_disable(); \
64 } while (0)
65
66 #define spin_lock_bh(_l) do { \
67 spin_lock(_l); \
68 local_bh_disable(); \
69 } while (0)
70
71 #define spin_lock_irq(_l) do { \
72 spin_lock(_l); \
73 } while (0)
74
75 #define spin_unlock(_l) do { \
76 if (SPIN_SKIP()) \
77 break; \
78 local_bh_enable(); \
79 mtx_unlock(_l); \
80 } while (0)
81
82 #define spin_unlock_bh(_l) do { \
83 local_bh_enable(); \
84 spin_unlock(_l); \
85 } while (0)
86
87 #define spin_unlock_irq(_l) do { \
88 spin_unlock(_l); \
89 } while (0)
90
91 #define spin_trylock(_l) ({ \
92 int __ret; \
93 if (SPIN_SKIP()) { \
94 __ret = 1; \
95 } else { \
96 __ret = mtx_trylock(_l); \
97 if (likely(__ret != 0)) \
98 local_bh_disable(); \
99 } \
100 __ret; \
101 })
102
103 #define spin_trylock_irq(_l) \
104 spin_trylock(_l)
105
106 #define spin_trylock_irqsave(_l, flags) ({ \
107 (flags) = 0; \
108 spin_trylock(_l); \
109 })
110
111 #define spin_lock_nested(_l, _n) do { \
112 if (SPIN_SKIP()) \
113 break; \
114 mtx_lock_flags(_l, MTX_DUPOK); \
115 local_bh_disable(); \
116 } while (0)
117
118 #define spin_lock_irqsave(_l, flags) do { \
119 (flags) = 0; \
120 spin_lock(_l); \
121 } while (0)
122
123 #define spin_lock_irqsave_nested(_l, flags, _n) do { \
124 (flags) = 0; \
125 spin_lock_nested(_l, _n); \
126 } while (0)
127
128 #define spin_unlock_irqrestore(_l, flags) do { \
129 (void)(flags); \
130 spin_unlock(_l); \
131 } while (0)
132
133 #ifdef WITNESS_ALL
134 /* NOTE: the maximum WITNESS name is 64 chars */
135 #define __spin_lock_name(name, file, line) \
136 (((const char *){file ":" #line "-" name}) + \
137 (sizeof(file) > 16 ? sizeof(file) - 16 : 0))
138 #else
139 #define __spin_lock_name(name, file, line) name
140 #endif
141 #define _spin_lock_name(...) __spin_lock_name(__VA_ARGS__)
142 #define spin_lock_name(name) _spin_lock_name(name, __FILE__, __LINE__)
143
144 #define spin_lock_init(lock) mtx_init(lock, spin_lock_name("lnxspin"), \
145 NULL, MTX_DEF | MTX_NOWITNESS | MTX_NEW)
146
147 #define spin_lock_destroy(_l) mtx_destroy(_l)
148
149 #define DEFINE_SPINLOCK(lock) \
150 spinlock_t lock; \
151 MTX_SYSINIT(lock, &lock, spin_lock_name("lnxspin"), MTX_DEF)
152
153 #define assert_spin_locked(_l) do { \
154 if (SPIN_SKIP()) \
155 break; \
156 mtx_assert(_l, MA_OWNED); \
157 } while (0)
158
159 #define local_irq_save(flags) do { \
160 (flags) = 0; \
161 } while (0)
162
163 #define local_irq_restore(flags) do { \
164 (void)(flags); \
165 } while (0)
166
167 #define atomic_dec_and_lock_irqsave(cnt, lock, flags) \
168 _atomic_dec_and_lock_irqsave(cnt, lock, &(flags))
169 static inline int
_atomic_dec_and_lock_irqsave(atomic_t * cnt,spinlock_t * lock,unsigned long * flags)170 _atomic_dec_and_lock_irqsave(atomic_t *cnt, spinlock_t *lock,
171 unsigned long *flags)
172 {
173 if (atomic_add_unless(cnt, -1, 1))
174 return (0);
175
176 spin_lock_irqsave(lock, *flags);
177 if (atomic_dec_and_test(cnt))
178 return (1);
179 spin_unlock_irqrestore(lock, *flags);
180 return (0);
181 }
182
183 /*
184 * struct raw_spinlock
185 */
186
187 typedef struct raw_spinlock {
188 struct mtx lock;
189 } raw_spinlock_t;
190
191 #define raw_spin_lock_init(rlock) \
192 mtx_init(&(rlock)->lock, spin_lock_name("lnxspin_raw"), \
193 NULL, MTX_DEF | MTX_NOWITNESS | MTX_NEW)
194
195 #define raw_spin_lock(rl) spin_lock(&(rl)->lock)
196 #define raw_spin_trylock(rl) spin_trylock(&(rl)->lock)
197 #define raw_spin_unlock(rl) spin_unlock(&(rl)->lock)
198
199 #define raw_spin_lock_irqsave(rl, f) spin_lock_irqsave(&(rl)->lock, (f))
200 #define raw_spin_trylock_irqsave(rl, f) spin_trylock_irqsave(&(rl)->lock, (f))
201 #define raw_spin_unlock_irqrestore(rl, f) spin_unlock_irqrestore(&(rl)->lock, (f))
202
203 /*
204 * cleanup.h related pre-defined cases.
205 */
206 DEFINE_LOCK_GUARD_1(spinlock_irqsave,
207 spinlock_t,
208 spin_lock_irqsave(_T->lock, _T->flags),
209 spin_unlock_irqrestore(_T->lock, _T->flags),
210 unsigned long flags)
211
212 #endif /* _LINUXKPI_LINUX_SPINLOCK_H_ */
213