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