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 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 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 129 mutex_is_owned(mutex_t *m) 130 { 131 return (sx_xlocked(&m->sx)); 132 } 133 134 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 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 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