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_SPINLOCK_H_ 30 #define _LINUXKPI_LINUX_SPINLOCK_H_ 31 32 #include <asm/atomic.h> 33 #include <sys/param.h> 34 #include <sys/kernel.h> 35 #include <sys/lock.h> 36 #include <sys/mutex.h> 37 #include <sys/kdb.h> 38 39 #include <linux/compiler.h> 40 #include <linux/rwlock.h> 41 #include <linux/bottom_half.h> 42 #include <linux/lockdep.h> 43 44 typedef struct { 45 struct mtx m; 46 } spinlock_t; 47 48 /* 49 * By defining CONFIG_SPIN_SKIP LinuxKPI spinlocks and asserts will be 50 * skipped during panic(). By default it is disabled due to 51 * performance reasons. 52 */ 53 #ifdef CONFIG_SPIN_SKIP 54 #define SPIN_SKIP(void) unlikely(SCHEDULER_STOPPED() || kdb_active) 55 #else 56 #define SPIN_SKIP(void) 0 57 #endif 58 59 #define spin_lock(_l) do { \ 60 if (SPIN_SKIP()) \ 61 break; \ 62 mtx_lock(&(_l)->m); \ 63 local_bh_disable(); \ 64 } while (0) 65 66 #define spin_lock_bh(_l) do { \ 67 spin_lock(_l); \ 68 local_bh_disable(); \ 69 } while (0) 70 71 #define spin_lock_irq(_l) do { \ 72 spin_lock(_l); \ 73 } while (0) 74 75 #define spin_unlock(_l) do { \ 76 if (SPIN_SKIP()) \ 77 break; \ 78 local_bh_enable(); \ 79 mtx_unlock(&(_l)->m); \ 80 } while (0) 81 82 #define spin_unlock_bh(_l) do { \ 83 local_bh_enable(); \ 84 spin_unlock(_l); \ 85 } while (0) 86 87 #define spin_unlock_irq(_l) do { \ 88 spin_unlock(_l); \ 89 } while (0) 90 91 #define spin_trylock(_l) ({ \ 92 int __ret; \ 93 if (SPIN_SKIP()) { \ 94 __ret = 1; \ 95 } else { \ 96 __ret = mtx_trylock(&(_l)->m); \ 97 if (likely(__ret != 0)) \ 98 local_bh_disable(); \ 99 } \ 100 __ret; \ 101 }) 102 103 #define spin_trylock_irq(_l) \ 104 spin_trylock(_l) 105 106 #define spin_trylock_irqsave(_l, flags) ({ \ 107 (flags) = 0; \ 108 spin_trylock(_l); \ 109 }) 110 111 #define spin_lock_nested(_l, _n) do { \ 112 if (SPIN_SKIP()) \ 113 break; \ 114 mtx_lock_flags(&(_l)->m, MTX_DUPOK); \ 115 local_bh_disable(); \ 116 } while (0) 117 118 #define spin_lock_irqsave(_l, flags) do { \ 119 (flags) = 0; \ 120 spin_lock(_l); \ 121 } while (0) 122 123 #define spin_lock_irqsave_nested(_l, flags, _n) do { \ 124 (flags) = 0; \ 125 spin_lock_nested(_l, _n); \ 126 } while (0) 127 128 #define spin_unlock_irqrestore(_l, flags) do { \ 129 (void)(flags); \ 130 spin_unlock(_l); \ 131 } while (0) 132 133 #ifdef WITNESS_ALL 134 /* NOTE: the maximum WITNESS name is 64 chars */ 135 #define __spin_lock_name(name, file, line) \ 136 (((const char *){file ":" #line "-" name}) + \ 137 (sizeof(file) > 16 ? sizeof(file) - 16 : 0)) 138 #else 139 #define __spin_lock_name(name, file, line) name 140 #endif 141 #define _spin_lock_name(...) __spin_lock_name(__VA_ARGS__) 142 #define spin_lock_name(name) _spin_lock_name(name, __FILE__, __LINE__) 143 144 #define spin_lock_init(lock) linux_spin_lock_init(lock, spin_lock_name("lnxspin")) 145 146 static inline void 147 linux_spin_lock_init(spinlock_t *lock, const char *name) 148 { 149 150 memset(lock, 0, sizeof(*lock)); 151 mtx_init(&lock->m, name, NULL, MTX_DEF | MTX_NOWITNESS); 152 } 153 154 static inline void 155 spin_lock_destroy(spinlock_t *lock) 156 { 157 158 mtx_destroy(&lock->m); 159 } 160 161 #define DEFINE_SPINLOCK(lock) \ 162 spinlock_t lock; \ 163 MTX_SYSINIT(lock, &(lock).m, spin_lock_name("lnxspin"), MTX_DEF) 164 165 #define assert_spin_locked(_l) do { \ 166 if (SPIN_SKIP()) \ 167 break; \ 168 mtx_assert(&(_l)->m, MA_OWNED); \ 169 } while (0) 170 171 #define atomic_dec_and_lock_irqsave(cnt, lock, flags) \ 172 _atomic_dec_and_lock_irqsave(cnt, lock, &(flags)) 173 static inline int 174 _atomic_dec_and_lock_irqsave(atomic_t *cnt, spinlock_t *lock, 175 unsigned long *flags) 176 { 177 if (atomic_add_unless(cnt, -1, 1)) 178 return (0); 179 180 spin_lock_irqsave(lock, *flags); 181 if (atomic_dec_and_test(cnt)) 182 return (1); 183 spin_unlock_irqrestore(lock, *flags); 184 return (0); 185 } 186 187 #endif /* _LINUXKPI_LINUX_SPINLOCK_H_ */ 188