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_MUTEX_H_
30 #define _LINUXKPI_LINUX_MUTEX_H_
31
32 #include <sys/param.h>
33 #include <sys/proc.h>
34 #include <sys/lock.h>
35 #include <sys/sx.h>
36
37 #include <linux/kernel.h>
38 #include <linux/list.h>
39 #include <linux/spinlock.h>
40 #include <asm/atomic.h>
41
42 typedef struct mutex {
43 struct sx sx;
44 } mutex_t;
45
46 /*
47 * By defining CONFIG_NO_MUTEX_SKIP LinuxKPI mutexes and asserts will
48 * not be skipped during panic().
49 */
50 #ifdef CONFIG_NO_MUTEX_SKIP
51 #define MUTEX_SKIP(void) 0
52 #else
53 #define MUTEX_SKIP(void) unlikely(SCHEDULER_STOPPED() || kdb_active)
54 #endif
55
56 #define mutex_lock(_m) do { \
57 if (MUTEX_SKIP()) \
58 break; \
59 sx_xlock(&(_m)->sx); \
60 } while (0)
61
62 #define mutex_lock_nested(_m, _s) mutex_lock(_m)
63 #define mutex_lock_nest_lock(_m, _s) mutex_lock(_m)
64
65 #define mutex_lock_interruptible(_m) ({ \
66 MUTEX_SKIP() ? 0 : \
67 linux_mutex_lock_interruptible(_m); \
68 })
69
70 #define mutex_lock_interruptible_nested(m, c) mutex_lock_interruptible(m)
71
72 /*
73 * Reuse the interruptable method since the SX
74 * lock handles both signals and interrupts:
75 */
76 #define mutex_lock_killable(_m) ({ \
77 MUTEX_SKIP() ? 0 : \
78 linux_mutex_lock_interruptible(_m); \
79 })
80
81 #define mutex_lock_killable_nested(_m, _sub) \
82 mutex_lock_killable(_m)
83
84 #define mutex_unlock(_m) do { \
85 if (MUTEX_SKIP()) \
86 break; \
87 sx_xunlock(&(_m)->sx); \
88 } while (0)
89
90 #define mutex_trylock(_m) ({ \
91 MUTEX_SKIP() ? 1 : \
92 !!sx_try_xlock(&(_m)->sx); \
93 })
94
95 enum mutex_trylock_recursive_enum {
96 MUTEX_TRYLOCK_FAILED = 0,
97 MUTEX_TRYLOCK_SUCCESS = 1,
98 MUTEX_TRYLOCK_RECURSIVE = 2,
99 };
100
101 static inline __must_check enum mutex_trylock_recursive_enum
mutex_trylock_recursive(struct mutex * lock)102 mutex_trylock_recursive(struct mutex *lock)
103 {
104 if (unlikely(sx_xholder(&lock->sx) == curthread))
105 return (MUTEX_TRYLOCK_RECURSIVE);
106
107 return (mutex_trylock(lock));
108 }
109
110 #define mutex_init(_m) \
111 linux_mutex_init(_m, mutex_name(#_m), SX_NOWITNESS)
112
113 #define __mutex_init(_m, _n, _l) \
114 linux_mutex_init(_m, _n, SX_NOWITNESS)
115
116 #define mutex_init_witness(_m) \
117 linux_mutex_init(_m, mutex_name(#_m), SX_DUPOK)
118
119 #define mutex_destroy(_m) \
120 linux_mutex_destroy(_m)
121
122 static inline bool
mutex_is_locked(mutex_t * m)123 mutex_is_locked(mutex_t *m)
124 {
125 return ((struct thread *)SX_OWNER(m->sx.sx_lock) != NULL);
126 }
127
128 static inline bool
mutex_is_owned(mutex_t * m)129 mutex_is_owned(mutex_t *m)
130 {
131 return (sx_xlocked(&m->sx));
132 }
133
atomic_dec_and_mutex_lock(atomic_t * cnt,struct mutex * m)134 static inline int atomic_dec_and_mutex_lock(atomic_t *cnt, struct mutex *m)
135 {
136 if (atomic_dec_and_test(cnt)) {
137 mutex_lock(m);
138 return (1);
139 }
140
141 return (0);
142 }
143
144 #ifdef WITNESS_ALL
145 /* NOTE: the maximum WITNESS name is 64 chars */
146 #define __mutex_name(name, file, line) \
147 (((const char *){file ":" #line "-" name}) + \
148 (sizeof(file) > 16 ? sizeof(file) - 16 : 0))
149 #else
150 #define __mutex_name(name, file, line) name
151 #endif
152 #define _mutex_name(...) __mutex_name(__VA_ARGS__)
153 #define mutex_name(name) _mutex_name(name, __FILE__, __LINE__)
154
155 #define DEFINE_MUTEX(lock) \
156 mutex_t lock; \
157 SX_SYSINIT_FLAGS(lock, &(lock).sx, mutex_name(#lock), SX_DUPOK)
158
159 static inline void
linux_mutex_init(mutex_t * m,const char * name,int flags)160 linux_mutex_init(mutex_t *m, const char *name, int flags)
161 {
162 memset(m, 0, sizeof(*m));
163 sx_init_flags(&m->sx, name, flags);
164 }
165
166 static inline void
linux_mutex_destroy(mutex_t * m)167 linux_mutex_destroy(mutex_t *m)
168 {
169 if (mutex_is_owned(m))
170 mutex_unlock(m);
171 sx_destroy(&m->sx);
172 }
173
174 extern int linux_mutex_lock_interruptible(mutex_t *m);
175
176 #endif /* _LINUXKPI_LINUX_MUTEX_H_ */
177