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