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/cleanup.h>
39 #include <linux/list.h>
40 #include <linux/spinlock.h>
41 #include <asm/atomic.h>
42
43 typedef struct mutex {
44 struct sx sx;
45 } mutex_t;
46
47 /*
48 * By defining CONFIG_NO_MUTEX_SKIP LinuxKPI mutexes and asserts will
49 * not be skipped during panic().
50 */
51 #ifdef CONFIG_NO_MUTEX_SKIP
52 #define MUTEX_SKIP(void) 0
53 #else
54 #define MUTEX_SKIP(void) unlikely(SCHEDULER_STOPPED() || kdb_active)
55 #endif
56
57 #define mutex_lock(_m) do { \
58 if (MUTEX_SKIP()) \
59 break; \
60 sx_xlock(&(_m)->sx); \
61 } while (0)
62
63 #define mutex_lock_nested(_m, _s) mutex_lock(_m)
64 #define mutex_lock_nest_lock(_m, _s) mutex_lock(_m)
65
66 #define mutex_lock_interruptible(_m) ({ \
67 MUTEX_SKIP() ? 0 : \
68 linux_mutex_lock_interruptible(_m); \
69 })
70
71 #define mutex_lock_interruptible_nested(m, c) mutex_lock_interruptible(m)
72
73 /*
74 * Reuse the interruptable method since the SX
75 * lock handles both signals and interrupts:
76 */
77 #define mutex_lock_killable(_m) ({ \
78 MUTEX_SKIP() ? 0 : \
79 linux_mutex_lock_interruptible(_m); \
80 })
81
82 #define mutex_lock_killable_nested(_m, _sub) \
83 mutex_lock_killable(_m)
84
85 #define mutex_unlock(_m) do { \
86 if (MUTEX_SKIP()) \
87 break; \
88 sx_xunlock(&(_m)->sx); \
89 } while (0)
90
91 #define mutex_trylock(_m) ({ \
92 MUTEX_SKIP() ? 1 : \
93 !!sx_try_xlock(&(_m)->sx); \
94 })
95
96 enum mutex_trylock_recursive_enum {
97 MUTEX_TRYLOCK_FAILED = 0,
98 MUTEX_TRYLOCK_SUCCESS = 1,
99 MUTEX_TRYLOCK_RECURSIVE = 2,
100 };
101
102 static inline __must_check enum mutex_trylock_recursive_enum
mutex_trylock_recursive(struct mutex * lock)103 mutex_trylock_recursive(struct mutex *lock)
104 {
105 if (unlikely(sx_xholder(&lock->sx) == curthread))
106 return (MUTEX_TRYLOCK_RECURSIVE);
107
108 return (mutex_trylock(lock));
109 }
110
111 #define mutex_init(_m) \
112 linux_mutex_init(_m, mutex_name(#_m), SX_NOWITNESS)
113
114 #define __mutex_init(_m, _n, _l) \
115 linux_mutex_init(_m, _n, SX_NOWITNESS)
116
117 #define mutex_init_witness(_m) \
118 linux_mutex_init(_m, mutex_name(#_m), SX_DUPOK)
119
120 #define mutex_destroy(_m) \
121 linux_mutex_destroy(_m)
122
123 static inline bool
mutex_is_locked(mutex_t * m)124 mutex_is_locked(mutex_t *m)
125 {
126 return ((struct thread *)SX_OWNER(m->sx.sx_lock) != NULL);
127 }
128
129 static inline bool
mutex_is_owned(mutex_t * m)130 mutex_is_owned(mutex_t *m)
131 {
132 return (sx_xlocked(&m->sx));
133 }
134
atomic_dec_and_mutex_lock(atomic_t * cnt,struct mutex * m)135 static inline int atomic_dec_and_mutex_lock(atomic_t *cnt, struct mutex *m)
136 {
137 if (atomic_dec_and_test(cnt)) {
138 mutex_lock(m);
139 return (1);
140 }
141
142 return (0);
143 }
144
145 #ifdef WITNESS_ALL
146 /* NOTE: the maximum WITNESS name is 64 chars */
147 #define __mutex_name(name, file, line) \
148 (((const char *){file ":" #line "-" name}) + \
149 (sizeof(file) > 16 ? sizeof(file) - 16 : 0))
150 #else
151 #define __mutex_name(name, file, line) name
152 #endif
153 #define _mutex_name(...) __mutex_name(__VA_ARGS__)
154 #define mutex_name(name) _mutex_name(name, __FILE__, __LINE__)
155
156 #define DEFINE_MUTEX(lock) \
157 mutex_t lock; \
158 SX_SYSINIT_FLAGS(lock, &(lock).sx, mutex_name(#lock), SX_DUPOK)
159
160 static inline void
linux_mutex_init(mutex_t * m,const char * name,int flags)161 linux_mutex_init(mutex_t *m, const char *name, int flags)
162 {
163 memset(m, 0, sizeof(*m));
164 sx_init_flags(&m->sx, name, flags);
165 }
166
167 static inline void
linux_mutex_destroy(mutex_t * m)168 linux_mutex_destroy(mutex_t *m)
169 {
170 if (mutex_is_owned(m))
171 mutex_unlock(m);
172 sx_destroy(&m->sx);
173 }
174
175 extern int linux_mutex_lock_interruptible(mutex_t *m);
176
177 #endif /* _LINUXKPI_LINUX_MUTEX_H_ */
178