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 /* 83 * Pull the __raw*() functions/declarations (UP-nondebug doesnt need them): 84 */ 85 #ifdef CONFIG_SMP 86 # include <asm/spinlock.h> 87 #else 88 # include <linux/spinlock_up.h> 89 #endif 90 91 #ifdef CONFIG_DEBUG_SPINLOCK 92 extern void __spin_lock_init(spinlock_t *lock, const char *name, 93 struct lock_class_key *key); 94 # define spin_lock_init(lock) \ 95 do { \ 96 static struct lock_class_key __key; \ 97 \ 98 __spin_lock_init((lock), #lock, &__key); \ 99 } while (0) 100 101 #else 102 # define spin_lock_init(lock) \ 103 do { *(lock) = __SPIN_LOCK_UNLOCKED(lock); } while (0) 104 #endif 105 106 #ifdef CONFIG_DEBUG_SPINLOCK 107 extern void __rwlock_init(rwlock_t *lock, const char *name, 108 struct lock_class_key *key); 109 # define rwlock_init(lock) \ 110 do { \ 111 static struct lock_class_key __key; \ 112 \ 113 __rwlock_init((lock), #lock, &__key); \ 114 } while (0) 115 #else 116 # define rwlock_init(lock) \ 117 do { *(lock) = __RW_LOCK_UNLOCKED(lock); } while (0) 118 #endif 119 120 #define spin_is_locked(lock) __raw_spin_is_locked(&(lock)->raw_lock) 121 122 #ifdef CONFIG_GENERIC_LOCKBREAK 123 #define spin_is_contended(lock) ((lock)->break_lock) 124 #else 125 126 #ifdef __raw_spin_is_contended 127 #define spin_is_contended(lock) __raw_spin_is_contended(&(lock)->raw_lock) 128 #else 129 #define spin_is_contended(lock) (((void)(lock), 0)) 130 #endif /*__raw_spin_is_contended*/ 131 #endif 132 133 /* The lock does not imply full memory barrier. */ 134 #ifndef ARCH_HAS_SMP_MB_AFTER_LOCK 135 static inline void smp_mb__after_lock(void) { smp_mb(); } 136 #endif 137 138 /** 139 * spin_unlock_wait - wait until the spinlock gets unlocked 140 * @lock: the spinlock in question. 141 */ 142 #define spin_unlock_wait(lock) __raw_spin_unlock_wait(&(lock)->raw_lock) 143 144 #ifdef CONFIG_DEBUG_SPINLOCK 145 extern void _raw_spin_lock(spinlock_t *lock); 146 #define _raw_spin_lock_flags(lock, flags) _raw_spin_lock(lock) 147 extern int _raw_spin_trylock(spinlock_t *lock); 148 extern void _raw_spin_unlock(spinlock_t *lock); 149 extern void _raw_read_lock(rwlock_t *lock); 150 #define _raw_read_lock_flags(lock, flags) _raw_read_lock(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 #define _raw_write_lock_flags(lock, flags) _raw_write_lock(lock) 155 extern int _raw_write_trylock(rwlock_t *lock); 156 extern void _raw_write_unlock(rwlock_t *lock); 157 #else 158 # define _raw_spin_lock(lock) __raw_spin_lock(&(lock)->raw_lock) 159 # define _raw_spin_lock_flags(lock, flags) \ 160 __raw_spin_lock_flags(&(lock)->raw_lock, *(flags)) 161 # define _raw_spin_trylock(lock) __raw_spin_trylock(&(lock)->raw_lock) 162 # define _raw_spin_unlock(lock) __raw_spin_unlock(&(lock)->raw_lock) 163 # define _raw_read_lock(rwlock) __raw_read_lock(&(rwlock)->raw_lock) 164 # define _raw_read_lock_flags(lock, flags) \ 165 __raw_read_lock_flags(&(lock)->raw_lock, *(flags)) 166 # define _raw_read_trylock(rwlock) __raw_read_trylock(&(rwlock)->raw_lock) 167 # define _raw_read_unlock(rwlock) __raw_read_unlock(&(rwlock)->raw_lock) 168 # define _raw_write_lock(rwlock) __raw_write_lock(&(rwlock)->raw_lock) 169 # define _raw_write_lock_flags(lock, flags) \ 170 __raw_write_lock_flags(&(lock)->raw_lock, *(flags)) 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 #define read_lock_irq(lock) _read_lock_irq(lock) 261 #define read_lock_bh(lock) _read_lock_bh(lock) 262 #define write_lock_irq(lock) _write_lock_irq(lock) 263 #define write_lock_bh(lock) _write_lock_bh(lock) 264 #define spin_unlock(lock) _spin_unlock(lock) 265 #define read_unlock(lock) _read_unlock(lock) 266 #define write_unlock(lock) _write_unlock(lock) 267 #define spin_unlock_irq(lock) _spin_unlock_irq(lock) 268 #define read_unlock_irq(lock) _read_unlock_irq(lock) 269 #define write_unlock_irq(lock) _write_unlock_irq(lock) 270 271 #define spin_unlock_irqrestore(lock, flags) \ 272 do { \ 273 typecheck(unsigned long, flags); \ 274 _spin_unlock_irqrestore(lock, flags); \ 275 } while (0) 276 #define spin_unlock_bh(lock) _spin_unlock_bh(lock) 277 278 #define read_unlock_irqrestore(lock, flags) \ 279 do { \ 280 typecheck(unsigned long, flags); \ 281 _read_unlock_irqrestore(lock, flags); \ 282 } while (0) 283 #define read_unlock_bh(lock) _read_unlock_bh(lock) 284 285 #define write_unlock_irqrestore(lock, flags) \ 286 do { \ 287 typecheck(unsigned long, flags); \ 288 _write_unlock_irqrestore(lock, flags); \ 289 } while (0) 290 #define write_unlock_bh(lock) _write_unlock_bh(lock) 291 292 #define spin_trylock_bh(lock) __cond_lock(lock, _spin_trylock_bh(lock)) 293 294 #define spin_trylock_irq(lock) \ 295 ({ \ 296 local_irq_disable(); \ 297 spin_trylock(lock) ? \ 298 1 : ({ local_irq_enable(); 0; }); \ 299 }) 300 301 #define spin_trylock_irqsave(lock, flags) \ 302 ({ \ 303 local_irq_save(flags); \ 304 spin_trylock(lock) ? \ 305 1 : ({ local_irq_restore(flags); 0; }); \ 306 }) 307 308 #define write_trylock_irqsave(lock, flags) \ 309 ({ \ 310 local_irq_save(flags); \ 311 write_trylock(lock) ? \ 312 1 : ({ local_irq_restore(flags); 0; }); \ 313 }) 314 315 /* 316 * Pull the atomic_t declaration: 317 * (asm-mips/atomic.h needs above definitions) 318 */ 319 #include <asm/atomic.h> 320 /** 321 * atomic_dec_and_lock - lock on reaching reference count zero 322 * @atomic: the atomic counter 323 * @lock: the spinlock in question 324 * 325 * Decrements @atomic by 1. If the result is 0, returns true and locks 326 * @lock. Returns false for all other cases. 327 */ 328 extern int _atomic_dec_and_lock(atomic_t *atomic, spinlock_t *lock); 329 #define atomic_dec_and_lock(atomic, lock) \ 330 __cond_lock(lock, _atomic_dec_and_lock(atomic, lock)) 331 332 /** 333 * spin_can_lock - would spin_trylock() succeed? 334 * @lock: the spinlock in question. 335 */ 336 #define spin_can_lock(lock) (!spin_is_locked(lock)) 337 338 /* 339 * Pull the _spin_*()/_read_*()/_write_*() functions/declarations: 340 */ 341 #if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK) 342 # include <linux/spinlock_api_smp.h> 343 #else 344 # include <linux/spinlock_api_up.h> 345 #endif 346 347 #endif /* __LINUX_SPINLOCK_H */ 348