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 /** 136 * spin_unlock_wait - wait until the spinlock gets unlocked 137 * @lock: the spinlock in question. 138 */ 139 #define spin_unlock_wait(lock) __raw_spin_unlock_wait(&(lock)->raw_lock) 140 141 /* 142 * Pull the _spin_*()/_read_*()/_write_*() functions/declarations: 143 */ 144 #if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK) 145 # include <linux/spinlock_api_smp.h> 146 #else 147 # include <linux/spinlock_api_up.h> 148 #endif 149 150 #ifdef CONFIG_DEBUG_SPINLOCK 151 extern void _raw_spin_lock(spinlock_t *lock); 152 #define _raw_spin_lock_flags(lock, flags) _raw_spin_lock(lock) 153 extern int _raw_spin_trylock(spinlock_t *lock); 154 extern void _raw_spin_unlock(spinlock_t *lock); 155 extern void _raw_read_lock(rwlock_t *lock); 156 #define _raw_read_lock_flags(lock, flags) _raw_read_lock(lock) 157 extern int _raw_read_trylock(rwlock_t *lock); 158 extern void _raw_read_unlock(rwlock_t *lock); 159 extern void _raw_write_lock(rwlock_t *lock); 160 #define _raw_write_lock_flags(lock, flags) _raw_write_lock(lock) 161 extern int _raw_write_trylock(rwlock_t *lock); 162 extern void _raw_write_unlock(rwlock_t *lock); 163 #else 164 # define _raw_spin_lock(lock) __raw_spin_lock(&(lock)->raw_lock) 165 # define _raw_spin_lock_flags(lock, flags) \ 166 __raw_spin_lock_flags(&(lock)->raw_lock, *(flags)) 167 # define _raw_spin_trylock(lock) __raw_spin_trylock(&(lock)->raw_lock) 168 # define _raw_spin_unlock(lock) __raw_spin_unlock(&(lock)->raw_lock) 169 # define _raw_read_lock(rwlock) __raw_read_lock(&(rwlock)->raw_lock) 170 # define _raw_read_lock_flags(lock, flags) \ 171 __raw_read_lock_flags(&(lock)->raw_lock, *(flags)) 172 # define _raw_read_trylock(rwlock) __raw_read_trylock(&(rwlock)->raw_lock) 173 # define _raw_read_unlock(rwlock) __raw_read_unlock(&(rwlock)->raw_lock) 174 # define _raw_write_lock(rwlock) __raw_write_lock(&(rwlock)->raw_lock) 175 # define _raw_write_lock_flags(lock, flags) \ 176 __raw_write_lock_flags(&(lock)->raw_lock, *(flags)) 177 # define _raw_write_trylock(rwlock) __raw_write_trylock(&(rwlock)->raw_lock) 178 # define _raw_write_unlock(rwlock) __raw_write_unlock(&(rwlock)->raw_lock) 179 #endif 180 181 #define read_can_lock(rwlock) __raw_read_can_lock(&(rwlock)->raw_lock) 182 #define write_can_lock(rwlock) __raw_write_can_lock(&(rwlock)->raw_lock) 183 184 /* 185 * Define the various spin_lock and rw_lock methods. Note we define these 186 * regardless of whether CONFIG_SMP or CONFIG_PREEMPT are set. The various 187 * methods are defined as nops in the case they are not required. 188 */ 189 #define spin_trylock(lock) __cond_lock(lock, _spin_trylock(lock)) 190 #define read_trylock(lock) __cond_lock(lock, _read_trylock(lock)) 191 #define write_trylock(lock) __cond_lock(lock, _write_trylock(lock)) 192 193 #define spin_lock(lock) _spin_lock(lock) 194 195 #ifdef CONFIG_DEBUG_LOCK_ALLOC 196 # define spin_lock_nested(lock, subclass) _spin_lock_nested(lock, subclass) 197 # define spin_lock_nest_lock(lock, nest_lock) \ 198 do { \ 199 typecheck(struct lockdep_map *, &(nest_lock)->dep_map);\ 200 _spin_lock_nest_lock(lock, &(nest_lock)->dep_map); \ 201 } while (0) 202 #else 203 # define spin_lock_nested(lock, subclass) _spin_lock(lock) 204 # define spin_lock_nest_lock(lock, nest_lock) _spin_lock(lock) 205 #endif 206 207 #define write_lock(lock) _write_lock(lock) 208 #define read_lock(lock) _read_lock(lock) 209 210 #if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK) 211 212 #define spin_lock_irqsave(lock, flags) \ 213 do { \ 214 typecheck(unsigned long, flags); \ 215 flags = _spin_lock_irqsave(lock); \ 216 } while (0) 217 #define read_lock_irqsave(lock, flags) \ 218 do { \ 219 typecheck(unsigned long, flags); \ 220 flags = _read_lock_irqsave(lock); \ 221 } while (0) 222 #define write_lock_irqsave(lock, flags) \ 223 do { \ 224 typecheck(unsigned long, flags); \ 225 flags = _write_lock_irqsave(lock); \ 226 } while (0) 227 228 #ifdef CONFIG_DEBUG_LOCK_ALLOC 229 #define spin_lock_irqsave_nested(lock, flags, subclass) \ 230 do { \ 231 typecheck(unsigned long, flags); \ 232 flags = _spin_lock_irqsave_nested(lock, subclass); \ 233 } while (0) 234 #else 235 #define spin_lock_irqsave_nested(lock, flags, subclass) \ 236 do { \ 237 typecheck(unsigned long, flags); \ 238 flags = _spin_lock_irqsave(lock); \ 239 } while (0) 240 #endif 241 242 #else 243 244 #define spin_lock_irqsave(lock, flags) \ 245 do { \ 246 typecheck(unsigned long, flags); \ 247 _spin_lock_irqsave(lock, flags); \ 248 } while (0) 249 #define read_lock_irqsave(lock, flags) \ 250 do { \ 251 typecheck(unsigned long, flags); \ 252 _read_lock_irqsave(lock, flags); \ 253 } while (0) 254 #define write_lock_irqsave(lock, flags) \ 255 do { \ 256 typecheck(unsigned long, flags); \ 257 _write_lock_irqsave(lock, flags); \ 258 } while (0) 259 #define spin_lock_irqsave_nested(lock, flags, subclass) \ 260 spin_lock_irqsave(lock, flags) 261 262 #endif 263 264 #define spin_lock_irq(lock) _spin_lock_irq(lock) 265 #define spin_lock_bh(lock) _spin_lock_bh(lock) 266 267 #define read_lock_irq(lock) _read_lock_irq(lock) 268 #define read_lock_bh(lock) _read_lock_bh(lock) 269 270 #define write_lock_irq(lock) _write_lock_irq(lock) 271 #define write_lock_bh(lock) _write_lock_bh(lock) 272 273 /* 274 * We inline the unlock functions in the nondebug case: 275 */ 276 #if defined(CONFIG_DEBUG_SPINLOCK) || defined(CONFIG_PREEMPT) || \ 277 !defined(CONFIG_SMP) 278 # define spin_unlock(lock) _spin_unlock(lock) 279 # define read_unlock(lock) _read_unlock(lock) 280 # define write_unlock(lock) _write_unlock(lock) 281 # define spin_unlock_irq(lock) _spin_unlock_irq(lock) 282 # define read_unlock_irq(lock) _read_unlock_irq(lock) 283 # define write_unlock_irq(lock) _write_unlock_irq(lock) 284 #else 285 # define spin_unlock(lock) \ 286 do {__raw_spin_unlock(&(lock)->raw_lock); __release(lock); } while (0) 287 # define read_unlock(lock) \ 288 do {__raw_read_unlock(&(lock)->raw_lock); __release(lock); } while (0) 289 # define write_unlock(lock) \ 290 do {__raw_write_unlock(&(lock)->raw_lock); __release(lock); } while (0) 291 # define spin_unlock_irq(lock) \ 292 do { \ 293 __raw_spin_unlock(&(lock)->raw_lock); \ 294 __release(lock); \ 295 local_irq_enable(); \ 296 } while (0) 297 # define read_unlock_irq(lock) \ 298 do { \ 299 __raw_read_unlock(&(lock)->raw_lock); \ 300 __release(lock); \ 301 local_irq_enable(); \ 302 } while (0) 303 # define write_unlock_irq(lock) \ 304 do { \ 305 __raw_write_unlock(&(lock)->raw_lock); \ 306 __release(lock); \ 307 local_irq_enable(); \ 308 } while (0) 309 #endif 310 311 #define spin_unlock_irqrestore(lock, flags) \ 312 do { \ 313 typecheck(unsigned long, flags); \ 314 _spin_unlock_irqrestore(lock, flags); \ 315 } while (0) 316 #define spin_unlock_bh(lock) _spin_unlock_bh(lock) 317 318 #define read_unlock_irqrestore(lock, flags) \ 319 do { \ 320 typecheck(unsigned long, flags); \ 321 _read_unlock_irqrestore(lock, flags); \ 322 } while (0) 323 #define read_unlock_bh(lock) _read_unlock_bh(lock) 324 325 #define write_unlock_irqrestore(lock, flags) \ 326 do { \ 327 typecheck(unsigned long, flags); \ 328 _write_unlock_irqrestore(lock, flags); \ 329 } while (0) 330 #define write_unlock_bh(lock) _write_unlock_bh(lock) 331 332 #define spin_trylock_bh(lock) __cond_lock(lock, _spin_trylock_bh(lock)) 333 334 #define spin_trylock_irq(lock) \ 335 ({ \ 336 local_irq_disable(); \ 337 spin_trylock(lock) ? \ 338 1 : ({ local_irq_enable(); 0; }); \ 339 }) 340 341 #define spin_trylock_irqsave(lock, flags) \ 342 ({ \ 343 local_irq_save(flags); \ 344 spin_trylock(lock) ? \ 345 1 : ({ local_irq_restore(flags); 0; }); \ 346 }) 347 348 #define write_trylock_irqsave(lock, flags) \ 349 ({ \ 350 local_irq_save(flags); \ 351 write_trylock(lock) ? \ 352 1 : ({ local_irq_restore(flags); 0; }); \ 353 }) 354 355 /* 356 * Pull the atomic_t declaration: 357 * (asm-mips/atomic.h needs above definitions) 358 */ 359 #include <asm/atomic.h> 360 /** 361 * atomic_dec_and_lock - lock on reaching reference count zero 362 * @atomic: the atomic counter 363 * @lock: the spinlock in question 364 * 365 * Decrements @atomic by 1. If the result is 0, returns true and locks 366 * @lock. Returns false for all other cases. 367 */ 368 extern int _atomic_dec_and_lock(atomic_t *atomic, spinlock_t *lock); 369 #define atomic_dec_and_lock(atomic, lock) \ 370 __cond_lock(lock, _atomic_dec_and_lock(atomic, lock)) 371 372 /** 373 * spin_can_lock - would spin_trylock() succeed? 374 * @lock: the spinlock in question. 375 */ 376 #define spin_can_lock(lock) (!spin_is_locked(lock)) 377 378 #endif /* __LINUX_SPINLOCK_H */ 379