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