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a900e28e | 1 | /* |
716154c5 BB |
2 | * Copyright (C) 2007-2010 Lawrence Livermore National Security, LLC. |
3 | * Copyright (C) 2007 The Regents of the University of California. | |
4 | * Produced at Lawrence Livermore National Laboratory (cf, DISCLAIMER). | |
5 | * Written by Brian Behlendorf <behlendorf1@llnl.gov>. | |
715f6251 | 6 | * UCRL-CODE-235197 |
7 | * | |
716154c5 | 8 | * This file is part of the SPL, Solaris Porting Layer. |
3d6af2dd | 9 | * For details, see <http://zfsonlinux.org/>. |
716154c5 BB |
10 | * |
11 | * The SPL is free software; you can redistribute it and/or modify it | |
12 | * under the terms of the GNU General Public License as published by the | |
13 | * Free Software Foundation; either version 2 of the License, or (at your | |
14 | * option) any later version. | |
715f6251 | 15 | * |
716154c5 | 16 | * The SPL is distributed in the hope that it will be useful, but WITHOUT |
715f6251 | 17 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
18 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
19 | * for more details. | |
20 | * | |
21 | * You should have received a copy of the GNU General Public License along | |
716154c5 | 22 | * with the SPL. If not, see <http://www.gnu.org/licenses/>. |
a900e28e | 23 | */ |
715f6251 | 24 | |
09b414e8 | 25 | #ifndef _SPL_MUTEX_H |
a900e28e | 26 | #define _SPL_MUTEX_H |
f1ca4da6 | 27 | |
f4b37741 | 28 | #include <sys/types.h> |
4d54fdee | 29 | #include <linux/mutex.h> |
22cd0f19 | 30 | #include <linux/compiler_compat.h> |
692ae8d3 | 31 | #include <linux/lockdep.h> |
4d54fdee BB |
32 | |
33 | typedef enum { | |
a900e28e BB |
34 | MUTEX_DEFAULT = 0, |
35 | MUTEX_SPIN = 1, | |
692ae8d3 OF |
36 | MUTEX_ADAPTIVE = 2, |
37 | MUTEX_NOLOCKDEP = 3 | |
4d54fdee | 38 | } kmutex_type_t; |
f1b59d26 | 39 | |
f1ca4da6 | 40 | typedef struct { |
a900e28e BB |
41 | struct mutex m_mutex; |
42 | spinlock_t m_lock; /* used for serializing mutex_exit */ | |
43 | kthread_t *m_owner; | |
692ae8d3 OF |
44 | #ifdef CONFIG_LOCKDEP |
45 | kmutex_type_t m_type; | |
46 | #endif /* CONFIG_LOCKDEP */ | |
f1ca4da6 | 47 | } kmutex_t; |
48 | ||
a900e28e | 49 | #define MUTEX(mp) (&((mp)->m_mutex)) |
ae26dd00 TC |
50 | |
51 | static inline void | |
52 | spl_mutex_set_owner(kmutex_t *mp) | |
53 | { | |
54 | mp->m_owner = current; | |
55 | } | |
56 | ||
57 | static inline void | |
58 | spl_mutex_clear_owner(kmutex_t *mp) | |
59 | { | |
60 | mp->m_owner = NULL; | |
61 | } | |
62 | ||
549423c0 | 63 | #define mutex_owner(mp) (ACCESS_ONCE((mp)->m_owner)) |
a900e28e BB |
64 | #define mutex_owned(mp) (mutex_owner(mp) == current) |
65 | #define MUTEX_HELD(mp) mutex_owned(mp) | |
66 | #define MUTEX_NOT_HELD(mp) (!MUTEX_HELD(mp)) | |
f1ca4da6 | 67 | |
692ae8d3 OF |
68 | #ifdef CONFIG_LOCKDEP |
69 | static inline void | |
70 | spl_mutex_set_type(kmutex_t *mp, kmutex_type_t type) | |
71 | { | |
72 | mp->m_type = type; | |
73 | } | |
74 | static inline void | |
75 | spl_mutex_lockdep_off_maybe(kmutex_t *mp) \ | |
76 | { \ | |
77 | if (mp && mp->m_type == MUTEX_NOLOCKDEP) \ | |
78 | lockdep_off(); \ | |
79 | } | |
80 | static inline void | |
81 | spl_mutex_lockdep_on_maybe(kmutex_t *mp) \ | |
82 | { \ | |
83 | if (mp && mp->m_type == MUTEX_NOLOCKDEP) \ | |
84 | lockdep_on(); \ | |
85 | } | |
86 | #else /* CONFIG_LOCKDEP */ | |
5461eefe BB |
87 | #define spl_mutex_set_type(mp, type) |
88 | #define spl_mutex_lockdep_off_maybe(mp) | |
89 | #define spl_mutex_lockdep_on_maybe(mp) | |
692ae8d3 OF |
90 | #endif /* CONFIG_LOCKDEP */ |
91 | ||
4d54fdee | 92 | /* |
5461eefe | 93 | * The following functions must be a #define and not static inline. |
4d54fdee BB |
94 | * This ensures that the native linux mutex functions (lock/unlock) |
95 | * will be correctly located in the users code which is important | |
96 | * for the built in kernel lock analysis tools | |
97 | */ | |
9ab1ac14 | 98 | #undef mutex_init |
a900e28e BB |
99 | #define mutex_init(mp, name, type, ibc) \ |
100 | { \ | |
101 | static struct lock_class_key __key; \ | |
692ae8d3 | 102 | ASSERT(type == MUTEX_DEFAULT || type == MUTEX_NOLOCKDEP); \ |
a900e28e | 103 | \ |
79a0056e | 104 | __mutex_init(MUTEX(mp), (name) ? (#name) : (#mp), &__key); \ |
a900e28e | 105 | spin_lock_init(&(mp)->m_lock); \ |
ae26dd00 | 106 | spl_mutex_clear_owner(mp); \ |
692ae8d3 | 107 | spl_mutex_set_type(mp, type); \ |
a900e28e | 108 | } |
4d54fdee | 109 | |
9ab1ac14 | 110 | #undef mutex_destroy |
a900e28e BB |
111 | #define mutex_destroy(mp) \ |
112 | { \ | |
113 | VERIFY3P(mutex_owner(mp), ==, NULL); \ | |
114 | } | |
d61e12af | 115 | |
5461eefe | 116 | /* BEGIN CSTYLED */ |
a900e28e BB |
117 | #define mutex_tryenter(mp) \ |
118 | ({ \ | |
119 | int _rc_; \ | |
120 | \ | |
692ae8d3 | 121 | spl_mutex_lockdep_off_maybe(mp); \ |
ae26dd00 TC |
122 | if ((_rc_ = mutex_trylock(MUTEX(mp))) == 1) \ |
123 | spl_mutex_set_owner(mp); \ | |
692ae8d3 | 124 | spl_mutex_lockdep_on_maybe(mp); \ |
a900e28e BB |
125 | \ |
126 | _rc_; \ | |
9ab1ac14 | 127 | }) |
5461eefe | 128 | /* END CSTYLED */ |
f1ca4da6 | 129 | |
79a0056e TC |
130 | #ifdef CONFIG_DEBUG_LOCK_ALLOC |
131 | #define mutex_enter_nested(mp, subclass) \ | |
132 | { \ | |
133 | ASSERT3P(mutex_owner(mp), !=, current); \ | |
692ae8d3 | 134 | spl_mutex_lockdep_off_maybe(mp); \ |
79a0056e | 135 | mutex_lock_nested(MUTEX(mp), (subclass)); \ |
692ae8d3 | 136 | spl_mutex_lockdep_on_maybe(mp); \ |
ae26dd00 | 137 | spl_mutex_set_owner(mp); \ |
79a0056e TC |
138 | } |
139 | #else /* CONFIG_DEBUG_LOCK_ALLOC */ | |
140 | #define mutex_enter_nested(mp, subclass) \ | |
a900e28e BB |
141 | { \ |
142 | ASSERT3P(mutex_owner(mp), !=, current); \ | |
692ae8d3 | 143 | spl_mutex_lockdep_off_maybe(mp); \ |
a900e28e | 144 | mutex_lock(MUTEX(mp)); \ |
692ae8d3 | 145 | spl_mutex_lockdep_on_maybe(mp); \ |
ae26dd00 | 146 | spl_mutex_set_owner(mp); \ |
a900e28e | 147 | } |
79a0056e TC |
148 | #endif /* CONFIG_DEBUG_LOCK_ALLOC */ |
149 | ||
150 | #define mutex_enter(mp) mutex_enter_nested((mp), 0) | |
4d54fdee | 151 | |
5f920fbe BB |
152 | /* |
153 | * The reason for the spinlock: | |
154 | * | |
155 | * The Linux mutex is designed with a fast-path/slow-path design such that it | |
156 | * does not guarantee serialization upon itself, allowing a race where latter | |
157 | * acquirers finish mutex_unlock before former ones. | |
158 | * | |
159 | * The race renders it unsafe to be used for serializing the freeing of an | |
160 | * object in which the mutex is embedded, where the latter acquirer could go | |
161 | * on to free the object while the former one is still doing mutex_unlock and | |
162 | * causing memory corruption. | |
163 | * | |
164 | * However, there are many places in ZFS where the mutex is used for | |
165 | * serializing object freeing, and the code is shared among other OSes without | |
166 | * this issue. Thus, we need the spinlock to force the serialization on | |
167 | * mutex_exit(). | |
168 | * | |
169 | * See http://lwn.net/Articles/575477/ for the information about the race. | |
170 | */ | |
a900e28e BB |
171 | #define mutex_exit(mp) \ |
172 | { \ | |
ae26dd00 | 173 | spl_mutex_clear_owner(mp); \ |
261a3151 GN |
174 | spin_lock(&(mp)->m_lock); \ |
175 | spl_mutex_lockdep_off_maybe(mp); \ | |
a900e28e | 176 | mutex_unlock(MUTEX(mp)); \ |
692ae8d3 | 177 | spl_mutex_lockdep_on_maybe(mp); \ |
261a3151 GN |
178 | spin_unlock(&(mp)->m_lock); \ |
179 | /* NOTE: do not dereference mp after this point */ \ | |
a900e28e | 180 | } |
4d54fdee | 181 | |
4d54fdee BB |
182 | int spl_mutex_init(void); |
183 | void spl_mutex_fini(void); | |
184 | ||
185 | #endif /* _SPL_MUTEX_H */ |