1 #ifndef __LINUX_SPINLOCK_H 2 #define __LINUX_SPINLOCK_H 3 4 /* 5 * include/linux/spinlock.h - generic spinlock/rwlock declarations 6 * 7 * here's the role of the various spinlock/rwlock related include files: 8 * 9 * on SMP builds: 10 * 11 * asm/spinlock_types.h: contains the raw_spinlock_t/raw_rwlock_t and the 12 * initializers 13 * 14 * linux/spinlock_types.h: 15 * defines the generic type and initializers 16 * 17 * asm/spinlock.h: contains the __raw_spin_*()/etc. lowlevel 18 * implementations, mostly inline assembly code 19 * 20 * (also included on UP-debug builds:) 21 * 22 * linux/spinlock_api_smp.h: 23 * contains the prototypes for the _spin_*() APIs. 24 * 25 * linux/spinlock.h: builds the final spin_*() APIs. 26 * 27 * on UP builds: 28 * 29 * linux/spinlock_type_up.h: 30 * contains the generic, simplified UP spinlock type. 31 * (which is an empty structure on non-debug builds) 32 * 33 * linux/spinlock_types.h: 34 * defines the generic type and initializers 35 * 36 * linux/spinlock_up.h: 37 * contains the __raw_spin_*()/etc. version of UP 38 * builds. (which are NOPs on non-debug, non-preempt 39 * builds) 40 * 41 * (included on UP-non-debug builds:) 42 * 43 * linux/spinlock_api_up.h: 44 * builds the _spin_*() APIs. 45 * 46 * linux/spinlock.h: builds the final spin_*() APIs. 47 */ 48 49 #include <linux/preempt.h> 50 #include <linux/linkage.h> 51 #include <linux/compiler.h> 52 #include <linux/thread_info.h> 53 #include <linux/kernel.h> 54 #include <linux/stringify.h> 55 #include <linux/bottom_half.h> 56 57 #include <asm/system.h> 58 59 /* 60 * Must define these before including other files, inline functions need them 61 */ 62 #define LOCK_SECTION_NAME ".text.lock."KBUILD_BASENAME 63 64 #define LOCK_SECTION_START(extra) \ 65 ".subsection 1\n\t" \ 66 extra \ 67 ".ifndef " LOCK_SECTION_NAME "\n\t" \ 68 LOCK_SECTION_NAME ":\n\t" \ 69 ".endif\n" 70 71 #define LOCK_SECTION_END \ 72 ".previous\n\t" 73 74 #define __lockfunc fastcall __attribute__((section(".spinlock.text"))) 75 76 /* 77 * Pull the raw_spinlock_t and raw_rwlock_t definitions: 78 */ 79 #include <linux/spinlock_types.h> 80 81 extern int __lockfunc generic__raw_read_trylock(raw_rwlock_t *lock); 82 83 /* 84 * Pull the __raw*() functions/declarations (UP-nondebug doesnt need them): 85 */ 86 #ifdef CONFIG_SMP 87 # include <asm/spinlock.h> 88 #else 89 # include <linux/spinlock_up.h> 90 #endif 91 92 #ifdef CONFIG_DEBUG_SPINLOCK 93 extern void __spin_lock_init(spinlock_t *lock, const char *name, 94 struct lock_class_key *key); 95 # define spin_lock_init(lock) \ 96 do { \ 97 static struct lock_class_key __key; \ 98 \ 99 __spin_lock_init((lock), #lock, &__key); \ 100 } while (0) 101 102 #else 103 # define spin_lock_init(lock) \ 104 do { *(lock) = SPIN_LOCK_UNLOCKED; } while (0) 105 #endif 106 107 #ifdef CONFIG_DEBUG_SPINLOCK 108 extern void __rwlock_init(rwlock_t *lock, const char *name, 109 struct lock_class_key *key); 110 # define rwlock_init(lock) \ 111 do { \ 112 static struct lock_class_key __key; \ 113 \ 114 __rwlock_init((lock), #lock, &__key); \ 115 } while (0) 116 #else 117 # define rwlock_init(lock) \ 118 do { *(lock) = RW_LOCK_UNLOCKED; } while (0) 119 #endif 120 121 #define spin_is_locked(lock) __raw_spin_is_locked(&(lock)->raw_lock) 122 123 /** 124 * spin_unlock_wait - wait until the spinlock gets unlocked 125 * @lock: the spinlock in question. 126 */ 127 #define spin_unlock_wait(lock) __raw_spin_unlock_wait(&(lock)->raw_lock) 128 129 /* 130 * Pull the _spin_*()/_read_*()/_write_*() functions/declarations: 131 */ 132 #if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK) 133 # include <linux/spinlock_api_smp.h> 134 #else 135 # include <linux/spinlock_api_up.h> 136 #endif 137 138 #ifdef CONFIG_DEBUG_SPINLOCK 139 extern void _raw_spin_lock(spinlock_t *lock); 140 #define _raw_spin_lock_flags(lock, flags) _raw_spin_lock(lock) 141 extern int _raw_spin_trylock(spinlock_t *lock); 142 extern void _raw_spin_unlock(spinlock_t *lock); 143 extern void _raw_read_lock(rwlock_t *lock); 144 extern int _raw_read_trylock(rwlock_t *lock); 145 extern void _raw_read_unlock(rwlock_t *lock); 146 extern void _raw_write_lock(rwlock_t *lock); 147 extern int _raw_write_trylock(rwlock_t *lock); 148 extern void _raw_write_unlock(rwlock_t *lock); 149 #else 150 # define _raw_spin_lock(lock) __raw_spin_lock(&(lock)->raw_lock) 151 # define _raw_spin_lock_flags(lock, flags) \ 152 __raw_spin_lock_flags(&(lock)->raw_lock, *(flags)) 153 # define _raw_spin_trylock(lock) __raw_spin_trylock(&(lock)->raw_lock) 154 # define _raw_spin_unlock(lock) __raw_spin_unlock(&(lock)->raw_lock) 155 # define _raw_read_lock(rwlock) __raw_read_lock(&(rwlock)->raw_lock) 156 # define _raw_read_trylock(rwlock) __raw_read_trylock(&(rwlock)->raw_lock) 157 # define _raw_read_unlock(rwlock) __raw_read_unlock(&(rwlock)->raw_lock) 158 # define _raw_write_lock(rwlock) __raw_write_lock(&(rwlock)->raw_lock) 159 # define _raw_write_trylock(rwlock) __raw_write_trylock(&(rwlock)->raw_lock) 160 # define _raw_write_unlock(rwlock) __raw_write_unlock(&(rwlock)->raw_lock) 161 #endif 162 163 #define read_can_lock(rwlock) __raw_read_can_lock(&(rwlock)->raw_lock) 164 #define write_can_lock(rwlock) __raw_write_can_lock(&(rwlock)->raw_lock) 165 166 /* 167 * Define the various spin_lock and rw_lock methods. Note we define these 168 * regardless of whether CONFIG_SMP or CONFIG_PREEMPT are set. The various 169 * methods are defined as nops in the case they are not required. 170 */ 171 #define spin_trylock(lock) __cond_lock(lock, _spin_trylock(lock)) 172 #define read_trylock(lock) __cond_lock(lock, _read_trylock(lock)) 173 #define write_trylock(lock) __cond_lock(lock, _write_trylock(lock)) 174 175 #define spin_lock(lock) _spin_lock(lock) 176 177 #ifdef CONFIG_DEBUG_LOCK_ALLOC 178 # define spin_lock_nested(lock, subclass) _spin_lock_nested(lock, subclass) 179 #else 180 # define spin_lock_nested(lock, subclass) _spin_lock(lock) 181 #endif 182 183 #define write_lock(lock) _write_lock(lock) 184 #define read_lock(lock) _read_lock(lock) 185 186 #if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK) 187 188 #define spin_lock_irqsave(lock, flags) flags = _spin_lock_irqsave(lock) 189 #define read_lock_irqsave(lock, flags) flags = _read_lock_irqsave(lock) 190 #define write_lock_irqsave(lock, flags) flags = _write_lock_irqsave(lock) 191 192 #ifdef CONFIG_DEBUG_LOCK_ALLOC 193 #define spin_lock_irqsave_nested(lock, flags, subclass) \ 194 flags = _spin_lock_irqsave_nested(lock, subclass) 195 #else 196 #define spin_lock_irqsave_nested(lock, flags, subclass) \ 197 flags = _spin_lock_irqsave(lock) 198 #endif 199 200 #else 201 202 #define spin_lock_irqsave(lock, flags) _spin_lock_irqsave(lock, flags) 203 #define read_lock_irqsave(lock, flags) _read_lock_irqsave(lock, flags) 204 #define write_lock_irqsave(lock, flags) _write_lock_irqsave(lock, flags) 205 #define spin_lock_irqsave_nested(lock, flags, subclass) \ 206 spin_lock_irqsave(lock, flags) 207 208 #endif 209 210 #define spin_lock_irq(lock) _spin_lock_irq(lock) 211 #define spin_lock_bh(lock) _spin_lock_bh(lock) 212 213 #define read_lock_irq(lock) _read_lock_irq(lock) 214 #define read_lock_bh(lock) _read_lock_bh(lock) 215 216 #define write_lock_irq(lock) _write_lock_irq(lock) 217 #define write_lock_bh(lock) _write_lock_bh(lock) 218 219 /* 220 * We inline the unlock functions in the nondebug case: 221 */ 222 #if defined(CONFIG_DEBUG_SPINLOCK) || defined(CONFIG_PREEMPT) || \ 223 !defined(CONFIG_SMP) 224 # define spin_unlock(lock) _spin_unlock(lock) 225 # define read_unlock(lock) _read_unlock(lock) 226 # define write_unlock(lock) _write_unlock(lock) 227 # define spin_unlock_irq(lock) _spin_unlock_irq(lock) 228 # define read_unlock_irq(lock) _read_unlock_irq(lock) 229 # define write_unlock_irq(lock) _write_unlock_irq(lock) 230 #else 231 # define spin_unlock(lock) \ 232 do {__raw_spin_unlock(&(lock)->raw_lock); __release(lock); } while (0) 233 # define read_unlock(lock) \ 234 do {__raw_read_unlock(&(lock)->raw_lock); __release(lock); } while (0) 235 # define write_unlock(lock) \ 236 do {__raw_write_unlock(&(lock)->raw_lock); __release(lock); } while (0) 237 # define spin_unlock_irq(lock) \ 238 do { \ 239 __raw_spin_unlock(&(lock)->raw_lock); \ 240 __release(lock); \ 241 local_irq_enable(); \ 242 } while (0) 243 # define read_unlock_irq(lock) \ 244 do { \ 245 __raw_read_unlock(&(lock)->raw_lock); \ 246 __release(lock); \ 247 local_irq_enable(); \ 248 } while (0) 249 # define write_unlock_irq(lock) \ 250 do { \ 251 __raw_write_unlock(&(lock)->raw_lock); \ 252 __release(lock); \ 253 local_irq_enable(); \ 254 } while (0) 255 #endif 256 257 #define spin_unlock_irqrestore(lock, flags) \ 258 _spin_unlock_irqrestore(lock, flags) 259 #define spin_unlock_bh(lock) _spin_unlock_bh(lock) 260 261 #define read_unlock_irqrestore(lock, flags) \ 262 _read_unlock_irqrestore(lock, flags) 263 #define read_unlock_bh(lock) _read_unlock_bh(lock) 264 265 #define write_unlock_irqrestore(lock, flags) \ 266 _write_unlock_irqrestore(lock, flags) 267 #define write_unlock_bh(lock) _write_unlock_bh(lock) 268 269 #define spin_trylock_bh(lock) __cond_lock(lock, _spin_trylock_bh(lock)) 270 271 #define spin_trylock_irq(lock) \ 272 ({ \ 273 local_irq_disable(); \ 274 spin_trylock(lock) ? \ 275 1 : ({ local_irq_enable(); 0; }); \ 276 }) 277 278 #define spin_trylock_irqsave(lock, flags) \ 279 ({ \ 280 local_irq_save(flags); \ 281 spin_trylock(lock) ? \ 282 1 : ({ local_irq_restore(flags); 0; }); \ 283 }) 284 285 /* 286 * Locks two spinlocks l1 and l2. 287 * l1_first indicates if spinlock l1 should be taken first. 288 */ 289 static inline void double_spin_lock(spinlock_t *l1, spinlock_t *l2, 290 bool l1_first) 291 __acquires(l1) 292 __acquires(l2) 293 { 294 if (l1_first) { 295 spin_lock(l1); 296 spin_lock(l2); 297 } else { 298 spin_lock(l2); 299 spin_lock(l1); 300 } 301 } 302 303 /* 304 * Unlocks two spinlocks l1 and l2. 305 * l1_taken_first indicates if spinlock l1 was taken first and therefore 306 * should be released after spinlock l2. 307 */ 308 static inline void double_spin_unlock(spinlock_t *l1, spinlock_t *l2, 309 bool l1_taken_first) 310 __releases(l1) 311 __releases(l2) 312 { 313 if (l1_taken_first) { 314 spin_unlock(l2); 315 spin_unlock(l1); 316 } else { 317 spin_unlock(l1); 318 spin_unlock(l2); 319 } 320 } 321 322 /* 323 * Pull the atomic_t declaration: 324 * (asm-mips/atomic.h needs above definitions) 325 */ 326 #include <asm/atomic.h> 327 /** 328 * atomic_dec_and_lock - lock on reaching reference count zero 329 * @atomic: the atomic counter 330 * @lock: the spinlock in question 331 */ 332 extern int _atomic_dec_and_lock(atomic_t *atomic, spinlock_t *lock); 333 #define atomic_dec_and_lock(atomic, lock) \ 334 __cond_lock(lock, _atomic_dec_and_lock(atomic, lock)) 335 336 /** 337 * spin_can_lock - would spin_trylock() succeed? 338 * @lock: the spinlock in question. 339 */ 340 #define spin_can_lock(lock) (!spin_is_locked(lock)) 341 342 #endif /* __LINUX_SPINLOCK_H */ 343