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 _LINUXKPI_LINUX_MUTEX_H_ 32 #define _LINUXKPI_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/kernel.h> 40 #include <linux/list.h> 41 #include <linux/spinlock.h> 42 #include <asm/atomic.h> 43 44 typedef struct mutex { 45 struct sx sx; 46 } mutex_t; 47 48 /* 49 * By defining CONFIG_NO_MUTEX_SKIP LinuxKPI mutexes and asserts will 50 * not be skipped during panic(). 51 */ 52 #ifdef CONFIG_NO_MUTEX_SKIP 53 #define MUTEX_SKIP(void) 0 54 #else 55 #define MUTEX_SKIP(void) unlikely(SCHEDULER_STOPPED() || kdb_active) 56 #endif 57 58 #define mutex_lock(_m) do { \ 59 if (MUTEX_SKIP()) \ 60 break; \ 61 sx_xlock(&(_m)->sx); \ 62 } while (0) 63 64 #define mutex_lock_nested(_m, _s) mutex_lock(_m) 65 #define mutex_lock_nest_lock(_m, _s) mutex_lock(_m) 66 67 #define mutex_lock_interruptible(_m) ({ \ 68 MUTEX_SKIP() ? 0 : \ 69 linux_mutex_lock_interruptible(_m); \ 70 }) 71 72 #define mutex_lock_interruptible_nested(m, c) mutex_lock_interruptible(m) 73 74 /* 75 * Reuse the interruptable method since the SX 76 * lock handles both signals and interrupts: 77 */ 78 #define mutex_lock_killable(_m) ({ \ 79 MUTEX_SKIP() ? 0 : \ 80 linux_mutex_lock_interruptible(_m); \ 81 }) 82 83 #define mutex_lock_killable_nested(_m, _sub) \ 84 mutex_lock_killable(_m) 85 86 #define mutex_unlock(_m) do { \ 87 if (MUTEX_SKIP()) \ 88 break; \ 89 sx_xunlock(&(_m)->sx); \ 90 } while (0) 91 92 #define mutex_trylock(_m) ({ \ 93 MUTEX_SKIP() ? 1 : \ 94 !!sx_try_xlock(&(_m)->sx); \ 95 }) 96 97 enum mutex_trylock_recursive_enum { 98 MUTEX_TRYLOCK_FAILED = 0, 99 MUTEX_TRYLOCK_SUCCESS = 1, 100 MUTEX_TRYLOCK_RECURSIVE = 2, 101 }; 102 103 static inline __must_check enum mutex_trylock_recursive_enum 104 mutex_trylock_recursive(struct mutex *lock) 105 { 106 if (unlikely(sx_xholder(&lock->sx) == curthread)) 107 return (MUTEX_TRYLOCK_RECURSIVE); 108 109 return (mutex_trylock(lock)); 110 } 111 112 #define mutex_init(_m) \ 113 linux_mutex_init(_m, mutex_name(#_m), SX_NOWITNESS) 114 115 #define __mutex_init(_m, _n, _l) \ 116 linux_mutex_init(_m, _n, SX_NOWITNESS) 117 118 #define mutex_init_witness(_m) \ 119 linux_mutex_init(_m, mutex_name(#_m), SX_DUPOK) 120 121 #define mutex_destroy(_m) \ 122 linux_mutex_destroy(_m) 123 124 static inline bool 125 mutex_is_locked(mutex_t *m) 126 { 127 return ((struct thread *)SX_OWNER(m->sx.sx_lock) != NULL); 128 } 129 130 static inline bool 131 mutex_is_owned(mutex_t *m) 132 { 133 return (sx_xlocked(&m->sx)); 134 } 135 136 static inline int atomic_dec_and_mutex_lock(atomic_t *cnt, struct mutex *m) 137 { 138 if (atomic_dec_and_test(cnt)) { 139 mutex_lock(m); 140 return (1); 141 } 142 143 return (0); 144 } 145 146 #ifdef WITNESS_ALL 147 /* NOTE: the maximum WITNESS name is 64 chars */ 148 #define __mutex_name(name, file, line) \ 149 (((const char *){file ":" #line "-" name}) + \ 150 (sizeof(file) > 16 ? sizeof(file) - 16 : 0)) 151 #else 152 #define __mutex_name(name, file, line) name 153 #endif 154 #define _mutex_name(...) __mutex_name(__VA_ARGS__) 155 #define mutex_name(name) _mutex_name(name, __FILE__, __LINE__) 156 157 #define DEFINE_MUTEX(lock) \ 158 mutex_t lock; \ 159 SX_SYSINIT_FLAGS(lock, &(lock).sx, mutex_name(#lock), SX_DUPOK) 160 161 static inline void 162 linux_mutex_init(mutex_t *m, const char *name, int flags) 163 { 164 memset(m, 0, sizeof(*m)); 165 sx_init_flags(&m->sx, name, flags); 166 } 167 168 static inline void 169 linux_mutex_destroy(mutex_t *m) 170 { 171 if (mutex_is_owned(m)) 172 mutex_unlock(m); 173 sx_destroy(&m->sx); 174 } 175 176 extern int linux_mutex_lock_interruptible(mutex_t *m); 177 178 #endif /* _LINUXKPI_LINUX_MUTEX_H_ */ 179