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 #define spin_is_contended(lock) __raw_spin_is_contended(&(lock)->raw_lock) 128 #endif 129 130 /** 131 * spin_unlock_wait - wait until the spinlock gets unlocked 132 * @lock: the spinlock in question. 133 */ 134 #define spin_unlock_wait(lock) __raw_spin_unlock_wait(&(lock)->raw_lock) 135 136 /* 137 * Pull the _spin_*()/_read_*()/_write_*() functions/declarations: 138 */ 139 #if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK) 140 # include <linux/spinlock_api_smp.h> 141 #else 142 # include <linux/spinlock_api_up.h> 143 #endif 144 145 #ifdef CONFIG_DEBUG_SPINLOCK 146 extern void _raw_spin_lock(spinlock_t *lock); 147 #define _raw_spin_lock_flags(lock, flags) _raw_spin_lock(lock) 148 extern int _raw_spin_trylock(spinlock_t *lock); 149 extern void _raw_spin_unlock(spinlock_t *lock); 150 extern void _raw_read_lock(rwlock_t *lock); 151 extern int _raw_read_trylock(rwlock_t *lock); 152 extern void _raw_read_unlock(rwlock_t *lock); 153 extern void _raw_write_lock(rwlock_t *lock); 154 extern int _raw_write_trylock(rwlock_t *lock); 155 extern void _raw_write_unlock(rwlock_t *lock); 156 #else 157 # define _raw_spin_lock(lock) __raw_spin_lock(&(lock)->raw_lock) 158 # define _raw_spin_lock_flags(lock, flags) \ 159 __raw_spin_lock_flags(&(lock)->raw_lock, *(flags)) 160 # define _raw_spin_trylock(lock) __raw_spin_trylock(&(lock)->raw_lock) 161 # define _raw_spin_unlock(lock) __raw_spin_unlock(&(lock)->raw_lock) 162 # define _raw_read_lock(rwlock) __raw_read_lock(&(rwlock)->raw_lock) 163 # define _raw_read_trylock(rwlock) __raw_read_trylock(&(rwlock)->raw_lock) 164 # define _raw_read_unlock(rwlock) __raw_read_unlock(&(rwlock)->raw_lock) 165 # define _raw_write_lock(rwlock) __raw_write_lock(&(rwlock)->raw_lock) 166 # define _raw_write_trylock(rwlock) __raw_write_trylock(&(rwlock)->raw_lock) 167 # define _raw_write_unlock(rwlock) __raw_write_unlock(&(rwlock)->raw_lock) 168 #endif 169 170 #define read_can_lock(rwlock) __raw_read_can_lock(&(rwlock)->raw_lock) 171 #define write_can_lock(rwlock) __raw_write_can_lock(&(rwlock)->raw_lock) 172 173 /* 174 * Define the various spin_lock and rw_lock methods. Note we define these 175 * regardless of whether CONFIG_SMP or CONFIG_PREEMPT are set. The various 176 * methods are defined as nops in the case they are not required. 177 */ 178 #define spin_trylock(lock) __cond_lock(lock, _spin_trylock(lock)) 179 #define read_trylock(lock) __cond_lock(lock, _read_trylock(lock)) 180 #define write_trylock(lock) __cond_lock(lock, _write_trylock(lock)) 181 182 #define spin_lock(lock) _spin_lock(lock) 183 184 #ifdef CONFIG_DEBUG_LOCK_ALLOC 185 # define spin_lock_nested(lock, subclass) _spin_lock_nested(lock, subclass) 186 #else 187 # define spin_lock_nested(lock, subclass) _spin_lock(lock) 188 #endif 189 190 #define write_lock(lock) _write_lock(lock) 191 #define read_lock(lock) _read_lock(lock) 192 193 #if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK) 194 195 #define spin_lock_irqsave(lock, flags) \ 196 do { \ 197 typecheck(unsigned long, flags); \ 198 flags = _spin_lock_irqsave(lock); \ 199 } while (0) 200 #define read_lock_irqsave(lock, flags) \ 201 do { \ 202 typecheck(unsigned long, flags); \ 203 flags = _read_lock_irqsave(lock); \ 204 } while (0) 205 #define write_lock_irqsave(lock, flags) \ 206 do { \ 207 typecheck(unsigned long, flags); \ 208 flags = _write_lock_irqsave(lock); \ 209 } while (0) 210 211 #ifdef CONFIG_DEBUG_LOCK_ALLOC 212 #define spin_lock_irqsave_nested(lock, flags, subclass) \ 213 do { \ 214 typecheck(unsigned long, flags); \ 215 flags = _spin_lock_irqsave_nested(lock, subclass); \ 216 } while (0) 217 #else 218 #define spin_lock_irqsave_nested(lock, flags, subclass) \ 219 do { \ 220 typecheck(unsigned long, flags); \ 221 flags = _spin_lock_irqsave(lock); \ 222 } while (0) 223 #endif 224 225 #else 226 227 #define spin_lock_irqsave(lock, flags) \ 228 do { \ 229 typecheck(unsigned long, flags); \ 230 _spin_lock_irqsave(lock, flags); \ 231 } while (0) 232 #define read_lock_irqsave(lock, flags) \ 233 do { \ 234 typecheck(unsigned long, flags); \ 235 _read_lock_irqsave(lock, flags); \ 236 } while (0) 237 #define write_lock_irqsave(lock, flags) \ 238 do { \ 239 typecheck(unsigned long, flags); \ 240 _write_lock_irqsave(lock, flags); \ 241 } while (0) 242 #define spin_lock_irqsave_nested(lock, flags, subclass) \ 243 spin_lock_irqsave(lock, flags) 244 245 #endif 246 247 #define spin_lock_irq(lock) _spin_lock_irq(lock) 248 #define spin_lock_bh(lock) _spin_lock_bh(lock) 249 250 #define read_lock_irq(lock) _read_lock_irq(lock) 251 #define read_lock_bh(lock) _read_lock_bh(lock) 252 253 #define write_lock_irq(lock) _write_lock_irq(lock) 254 #define write_lock_bh(lock) _write_lock_bh(lock) 255 256 /* 257 * We inline the unlock functions in the nondebug case: 258 */ 259 #if defined(CONFIG_DEBUG_SPINLOCK) || defined(CONFIG_PREEMPT) || \ 260 !defined(CONFIG_SMP) 261 # define spin_unlock(lock) _spin_unlock(lock) 262 # define read_unlock(lock) _read_unlock(lock) 263 # define write_unlock(lock) _write_unlock(lock) 264 # define spin_unlock_irq(lock) _spin_unlock_irq(lock) 265 # define read_unlock_irq(lock) _read_unlock_irq(lock) 266 # define write_unlock_irq(lock) _write_unlock_irq(lock) 267 #else 268 # define spin_unlock(lock) \ 269 do {__raw_spin_unlock(&(lock)->raw_lock); __release(lock); } while (0) 270 # define read_unlock(lock) \ 271 do {__raw_read_unlock(&(lock)->raw_lock); __release(lock); } while (0) 272 # define write_unlock(lock) \ 273 do {__raw_write_unlock(&(lock)->raw_lock); __release(lock); } while (0) 274 # define spin_unlock_irq(lock) \ 275 do { \ 276 __raw_spin_unlock(&(lock)->raw_lock); \ 277 __release(lock); \ 278 local_irq_enable(); \ 279 } while (0) 280 # define read_unlock_irq(lock) \ 281 do { \ 282 __raw_read_unlock(&(lock)->raw_lock); \ 283 __release(lock); \ 284 local_irq_enable(); \ 285 } while (0) 286 # define write_unlock_irq(lock) \ 287 do { \ 288 __raw_write_unlock(&(lock)->raw_lock); \ 289 __release(lock); \ 290 local_irq_enable(); \ 291 } while (0) 292 #endif 293 294 #define spin_unlock_irqrestore(lock, flags) \ 295 do { \ 296 typecheck(unsigned long, flags); \ 297 _spin_unlock_irqrestore(lock, flags); \ 298 } while (0) 299 #define spin_unlock_bh(lock) _spin_unlock_bh(lock) 300 301 #define read_unlock_irqrestore(lock, flags) \ 302 do { \ 303 typecheck(unsigned long, flags); \ 304 _read_unlock_irqrestore(lock, flags); \ 305 } while (0) 306 #define read_unlock_bh(lock) _read_unlock_bh(lock) 307 308 #define write_unlock_irqrestore(lock, flags) \ 309 do { \ 310 typecheck(unsigned long, flags); \ 311 _write_unlock_irqrestore(lock, flags); \ 312 } while (0) 313 #define write_unlock_bh(lock) _write_unlock_bh(lock) 314 315 #define spin_trylock_bh(lock) __cond_lock(lock, _spin_trylock_bh(lock)) 316 317 #define spin_trylock_irq(lock) \ 318 ({ \ 319 local_irq_disable(); \ 320 spin_trylock(lock) ? \ 321 1 : ({ local_irq_enable(); 0; }); \ 322 }) 323 324 #define spin_trylock_irqsave(lock, flags) \ 325 ({ \ 326 local_irq_save(flags); \ 327 spin_trylock(lock) ? \ 328 1 : ({ local_irq_restore(flags); 0; }); \ 329 }) 330 331 #define write_trylock_irqsave(lock, flags) \ 332 ({ \ 333 local_irq_save(flags); \ 334 write_trylock(lock) ? \ 335 1 : ({ local_irq_restore(flags); 0; }); \ 336 }) 337 338 /* 339 * Pull the atomic_t declaration: 340 * (asm-mips/atomic.h needs above definitions) 341 */ 342 #include <asm/atomic.h> 343 /** 344 * atomic_dec_and_lock - lock on reaching reference count zero 345 * @atomic: the atomic counter 346 * @lock: the spinlock in question 347 * 348 * Decrements @atomic by 1. If the result is 0, returns true and locks 349 * @lock. Returns false for all other cases. 350 */ 351 extern int _atomic_dec_and_lock(atomic_t *atomic, spinlock_t *lock); 352 #define atomic_dec_and_lock(atomic, lock) \ 353 __cond_lock(lock, _atomic_dec_and_lock(atomic, lock)) 354 355 /** 356 * spin_can_lock - would spin_trylock() succeed? 357 * @lock: the spinlock in question. 358 */ 359 #define spin_can_lock(lock) (!spin_is_locked(lock)) 360 361 #endif /* __LINUX_SPINLOCK_H */ 362