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/typecheck.h> 50 #include <linux/preempt.h> 51 #include <linux/linkage.h> 52 #include <linux/compiler.h> 53 #include <linux/thread_info.h> 54 #include <linux/kernel.h> 55 #include <linux/stringify.h> 56 #include <linux/bottom_half.h> 57 58 #include <asm/system.h> 59 60 /* 61 * Must define these before including other files, inline functions need them 62 */ 63 #define LOCK_SECTION_NAME ".text.lock."KBUILD_BASENAME 64 65 #define LOCK_SECTION_START(extra) \ 66 ".subsection 1\n\t" \ 67 extra \ 68 ".ifndef " LOCK_SECTION_NAME "\n\t" \ 69 LOCK_SECTION_NAME ":\n\t" \ 70 ".endif\n" 71 72 #define LOCK_SECTION_END \ 73 ".previous\n\t" 74 75 #define __lockfunc __attribute__((section(".spinlock.text"))) 76 77 /* 78 * Pull the raw_spinlock_t and raw_rwlock_t definitions: 79 */ 80 #include <linux/spinlock_types.h> 81 82 extern int __lockfunc generic__raw_read_trylock(raw_rwlock_t *lock); 83 84 /* 85 * Pull the __raw*() functions/declarations (UP-nondebug doesnt need them): 86 */ 87 #ifdef CONFIG_SMP 88 # include <asm/spinlock.h> 89 #else 90 # include <linux/spinlock_up.h> 91 #endif 92 93 #ifdef CONFIG_DEBUG_SPINLOCK 94 extern void __spin_lock_init(spinlock_t *lock, const char *name, 95 struct lock_class_key *key); 96 # define spin_lock_init(lock) \ 97 do { \ 98 static struct lock_class_key __key; \ 99 \ 100 __spin_lock_init((lock), #lock, &__key); \ 101 } while (0) 102 103 #else 104 # define spin_lock_init(lock) \ 105 do { *(lock) = SPIN_LOCK_UNLOCKED; } while (0) 106 #endif 107 108 #ifdef CONFIG_DEBUG_SPINLOCK 109 extern void __rwlock_init(rwlock_t *lock, const char *name, 110 struct lock_class_key *key); 111 # define rwlock_init(lock) \ 112 do { \ 113 static struct lock_class_key __key; \ 114 \ 115 __rwlock_init((lock), #lock, &__key); \ 116 } while (0) 117 #else 118 # define rwlock_init(lock) \ 119 do { *(lock) = RW_LOCK_UNLOCKED; } while (0) 120 #endif 121 122 #define spin_is_locked(lock) __raw_spin_is_locked(&(lock)->raw_lock) 123 124 #ifdef CONFIG_GENERIC_LOCKBREAK 125 #define spin_is_contended(lock) ((lock)->break_lock) 126 #else 127 128 #ifdef __raw_spin_is_contended 129 #define spin_is_contended(lock) __raw_spin_is_contended(&(lock)->raw_lock) 130 #else 131 #define spin_is_contended(lock) (((void)(lock), 0)) 132 #endif /*__raw_spin_is_contended*/ 133 #endif 134 135 /* The lock does not imply full memory barrier. */ 136 #ifndef ARCH_HAS_SMP_MB_AFTER_LOCK 137 static inline void smp_mb__after_lock(void) { smp_mb(); } 138 #endif 139 140 /** 141 * spin_unlock_wait - wait until the spinlock gets unlocked 142 * @lock: the spinlock in question. 143 */ 144 #define spin_unlock_wait(lock) __raw_spin_unlock_wait(&(lock)->raw_lock) 145 146 /* 147 * Pull the _spin_*()/_read_*()/_write_*() functions/declarations: 148 */ 149 #if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK) 150 # include <linux/spinlock_api_smp.h> 151 #else 152 # include <linux/spinlock_api_up.h> 153 #endif 154 155 #ifdef CONFIG_DEBUG_SPINLOCK 156 extern void _raw_spin_lock(spinlock_t *lock); 157 #define _raw_spin_lock_flags(lock, flags) _raw_spin_lock(lock) 158 extern int _raw_spin_trylock(spinlock_t *lock); 159 extern void _raw_spin_unlock(spinlock_t *lock); 160 extern void _raw_read_lock(rwlock_t *lock); 161 #define _raw_read_lock_flags(lock, flags) _raw_read_lock(lock) 162 extern int _raw_read_trylock(rwlock_t *lock); 163 extern void _raw_read_unlock(rwlock_t *lock); 164 extern void _raw_write_lock(rwlock_t *lock); 165 #define _raw_write_lock_flags(lock, flags) _raw_write_lock(lock) 166 extern int _raw_write_trylock(rwlock_t *lock); 167 extern void _raw_write_unlock(rwlock_t *lock); 168 #else 169 # define _raw_spin_lock(lock) __raw_spin_lock(&(lock)->raw_lock) 170 # define _raw_spin_lock_flags(lock, flags) \ 171 __raw_spin_lock_flags(&(lock)->raw_lock, *(flags)) 172 # define _raw_spin_trylock(lock) __raw_spin_trylock(&(lock)->raw_lock) 173 # define _raw_spin_unlock(lock) __raw_spin_unlock(&(lock)->raw_lock) 174 # define _raw_read_lock(rwlock) __raw_read_lock(&(rwlock)->raw_lock) 175 # define _raw_read_lock_flags(lock, flags) \ 176 __raw_read_lock_flags(&(lock)->raw_lock, *(flags)) 177 # define _raw_read_trylock(rwlock) __raw_read_trylock(&(rwlock)->raw_lock) 178 # define _raw_read_unlock(rwlock) __raw_read_unlock(&(rwlock)->raw_lock) 179 # define _raw_write_lock(rwlock) __raw_write_lock(&(rwlock)->raw_lock) 180 # define _raw_write_lock_flags(lock, flags) \ 181 __raw_write_lock_flags(&(lock)->raw_lock, *(flags)) 182 # define _raw_write_trylock(rwlock) __raw_write_trylock(&(rwlock)->raw_lock) 183 # define _raw_write_unlock(rwlock) __raw_write_unlock(&(rwlock)->raw_lock) 184 #endif 185 186 #define read_can_lock(rwlock) __raw_read_can_lock(&(rwlock)->raw_lock) 187 #define write_can_lock(rwlock) __raw_write_can_lock(&(rwlock)->raw_lock) 188 189 /* 190 * Define the various spin_lock and rw_lock methods. Note we define these 191 * regardless of whether CONFIG_SMP or CONFIG_PREEMPT are set. The various 192 * methods are defined as nops in the case they are not required. 193 */ 194 #define spin_trylock(lock) __cond_lock(lock, _spin_trylock(lock)) 195 #define read_trylock(lock) __cond_lock(lock, _read_trylock(lock)) 196 #define write_trylock(lock) __cond_lock(lock, _write_trylock(lock)) 197 198 #define spin_lock(lock) _spin_lock(lock) 199 200 #ifdef CONFIG_DEBUG_LOCK_ALLOC 201 # define spin_lock_nested(lock, subclass) _spin_lock_nested(lock, subclass) 202 # define spin_lock_nest_lock(lock, nest_lock) \ 203 do { \ 204 typecheck(struct lockdep_map *, &(nest_lock)->dep_map);\ 205 _spin_lock_nest_lock(lock, &(nest_lock)->dep_map); \ 206 } while (0) 207 #else 208 # define spin_lock_nested(lock, subclass) _spin_lock(lock) 209 # define spin_lock_nest_lock(lock, nest_lock) _spin_lock(lock) 210 #endif 211 212 #define write_lock(lock) _write_lock(lock) 213 #define read_lock(lock) _read_lock(lock) 214 215 #if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK) 216 217 #define spin_lock_irqsave(lock, flags) \ 218 do { \ 219 typecheck(unsigned long, flags); \ 220 flags = _spin_lock_irqsave(lock); \ 221 } while (0) 222 #define read_lock_irqsave(lock, flags) \ 223 do { \ 224 typecheck(unsigned long, flags); \ 225 flags = _read_lock_irqsave(lock); \ 226 } while (0) 227 #define write_lock_irqsave(lock, flags) \ 228 do { \ 229 typecheck(unsigned long, flags); \ 230 flags = _write_lock_irqsave(lock); \ 231 } while (0) 232 233 #ifdef CONFIG_DEBUG_LOCK_ALLOC 234 #define spin_lock_irqsave_nested(lock, flags, subclass) \ 235 do { \ 236 typecheck(unsigned long, flags); \ 237 flags = _spin_lock_irqsave_nested(lock, subclass); \ 238 } while (0) 239 #else 240 #define spin_lock_irqsave_nested(lock, flags, subclass) \ 241 do { \ 242 typecheck(unsigned long, flags); \ 243 flags = _spin_lock_irqsave(lock); \ 244 } while (0) 245 #endif 246 247 #else 248 249 #define spin_lock_irqsave(lock, flags) \ 250 do { \ 251 typecheck(unsigned long, flags); \ 252 _spin_lock_irqsave(lock, flags); \ 253 } while (0) 254 #define read_lock_irqsave(lock, flags) \ 255 do { \ 256 typecheck(unsigned long, flags); \ 257 _read_lock_irqsave(lock, flags); \ 258 } while (0) 259 #define write_lock_irqsave(lock, flags) \ 260 do { \ 261 typecheck(unsigned long, flags); \ 262 _write_lock_irqsave(lock, flags); \ 263 } while (0) 264 #define spin_lock_irqsave_nested(lock, flags, subclass) \ 265 spin_lock_irqsave(lock, flags) 266 267 #endif 268 269 #define spin_lock_irq(lock) _spin_lock_irq(lock) 270 #define spin_lock_bh(lock) _spin_lock_bh(lock) 271 272 #define read_lock_irq(lock) _read_lock_irq(lock) 273 #define read_lock_bh(lock) _read_lock_bh(lock) 274 275 #define write_lock_irq(lock) _write_lock_irq(lock) 276 #define write_lock_bh(lock) _write_lock_bh(lock) 277 278 /* 279 * We inline the unlock functions in the nondebug case: 280 */ 281 #if defined(CONFIG_DEBUG_SPINLOCK) || defined(CONFIG_PREEMPT) || \ 282 !defined(CONFIG_SMP) 283 # define spin_unlock(lock) _spin_unlock(lock) 284 # define read_unlock(lock) _read_unlock(lock) 285 # define write_unlock(lock) _write_unlock(lock) 286 # define spin_unlock_irq(lock) _spin_unlock_irq(lock) 287 # define read_unlock_irq(lock) _read_unlock_irq(lock) 288 # define write_unlock_irq(lock) _write_unlock_irq(lock) 289 #else 290 # define spin_unlock(lock) \ 291 do {__raw_spin_unlock(&(lock)->raw_lock); __release(lock); } while (0) 292 # define read_unlock(lock) \ 293 do {__raw_read_unlock(&(lock)->raw_lock); __release(lock); } while (0) 294 # define write_unlock(lock) \ 295 do {__raw_write_unlock(&(lock)->raw_lock); __release(lock); } while (0) 296 # define spin_unlock_irq(lock) \ 297 do { \ 298 __raw_spin_unlock(&(lock)->raw_lock); \ 299 __release(lock); \ 300 local_irq_enable(); \ 301 } while (0) 302 # define read_unlock_irq(lock) \ 303 do { \ 304 __raw_read_unlock(&(lock)->raw_lock); \ 305 __release(lock); \ 306 local_irq_enable(); \ 307 } while (0) 308 # define write_unlock_irq(lock) \ 309 do { \ 310 __raw_write_unlock(&(lock)->raw_lock); \ 311 __release(lock); \ 312 local_irq_enable(); \ 313 } while (0) 314 #endif 315 316 #define spin_unlock_irqrestore(lock, flags) \ 317 do { \ 318 typecheck(unsigned long, flags); \ 319 _spin_unlock_irqrestore(lock, flags); \ 320 } while (0) 321 #define spin_unlock_bh(lock) _spin_unlock_bh(lock) 322 323 #define read_unlock_irqrestore(lock, flags) \ 324 do { \ 325 typecheck(unsigned long, flags); \ 326 _read_unlock_irqrestore(lock, flags); \ 327 } while (0) 328 #define read_unlock_bh(lock) _read_unlock_bh(lock) 329 330 #define write_unlock_irqrestore(lock, flags) \ 331 do { \ 332 typecheck(unsigned long, flags); \ 333 _write_unlock_irqrestore(lock, flags); \ 334 } while (0) 335 #define write_unlock_bh(lock) _write_unlock_bh(lock) 336 337 #define spin_trylock_bh(lock) __cond_lock(lock, _spin_trylock_bh(lock)) 338 339 #define spin_trylock_irq(lock) \ 340 ({ \ 341 local_irq_disable(); \ 342 spin_trylock(lock) ? \ 343 1 : ({ local_irq_enable(); 0; }); \ 344 }) 345 346 #define spin_trylock_irqsave(lock, flags) \ 347 ({ \ 348 local_irq_save(flags); \ 349 spin_trylock(lock) ? \ 350 1 : ({ local_irq_restore(flags); 0; }); \ 351 }) 352 353 #define write_trylock_irqsave(lock, flags) \ 354 ({ \ 355 local_irq_save(flags); \ 356 write_trylock(lock) ? \ 357 1 : ({ local_irq_restore(flags); 0; }); \ 358 }) 359 360 /* 361 * Pull the atomic_t declaration: 362 * (asm-mips/atomic.h needs above definitions) 363 */ 364 #include <asm/atomic.h> 365 /** 366 * atomic_dec_and_lock - lock on reaching reference count zero 367 * @atomic: the atomic counter 368 * @lock: the spinlock in question 369 * 370 * Decrements @atomic by 1. If the result is 0, returns true and locks 371 * @lock. Returns false for all other cases. 372 */ 373 extern int _atomic_dec_and_lock(atomic_t *atomic, spinlock_t *lock); 374 #define atomic_dec_and_lock(atomic, lock) \ 375 __cond_lock(lock, _atomic_dec_and_lock(atomic, lock)) 376 377 /** 378 * spin_can_lock - would spin_trylock() succeed? 379 * @lock: the spinlock in question. 380 */ 381 #define spin_can_lock(lock) (!spin_is_locked(lock)) 382 383 #endif /* __LINUX_SPINLOCK_H */ 384