include/linux/spinlock.h

   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 arch_spinlock_t/arch_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 arch_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 arch_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 arch_spinlock_t and arch_rwlock_t definitions:
  79  */
  80 #include <linux/spinlock_types.h>
  81
  82 /*
  83  * Pull the arch_spin*() 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 __raw_spin_lock_init(raw_spinlock_t *lock, const char *name,
  93                                    struct lock_class_key *key);
  94 # define raw_spin_lock_init(lock)                               \
  95 do {                                                            \
  96         static struct lock_class_key __key;                     \
  97                                                                 \
  98         __raw_spin_lock_init((lock), #lock, &__key);            \
  99 } while (0)
 100
 101 #else
 102 # define raw_spin_lock_init(lock)                               \
 103         do { *(lock) = __RAW_SPIN_LOCK_UNLOCKED(lock); } while (0)
 104 #endif
 105
 106 #define raw_spin_is_locked(lock)        arch_spin_is_locked(&(lock)->raw_lock)
 107
 108 #ifdef CONFIG_GENERIC_LOCKBREAK
 109 #define raw_spin_is_contended(lock) ((lock)->break_lock)
 110 #else
 111
 112 #ifdef arch_spin_is_contended
 113 #define raw_spin_is_contended(lock)     arch_spin_is_contended(&(lock)->raw_lock)
 114 #else
 115 #define raw_spin_is_contended(lock)     (((void)(lock), 0))
 116 #endif /*arch_spin_is_contended*/
 117 #endif
 118
 119 /* The lock does not imply full memory barrier. */
 120 #ifndef ARCH_HAS_SMP_MB_AFTER_LOCK
 121 static inline void smp_mb__after_lock(void) { smp_mb(); }
 122 #endif
 123
 124 /**
 125  * raw_spin_unlock_wait - wait until the spinlock gets unlocked
 126  * @lock: the spinlock in question.
 127  */
 128 #define raw_spin_unlock_wait(lock)      arch_spin_unlock_wait(&(lock)->raw_lock)
 129
 130 #ifdef CONFIG_DEBUG_SPINLOCK
 131  extern void do_raw_spin_lock(raw_spinlock_t *lock);
 132 #define do_raw_spin_lock_flags(lock, flags) do_raw_spin_lock(lock)
 133  extern int do_raw_spin_trylock(raw_spinlock_t *lock);
 134  extern void do_raw_spin_unlock(raw_spinlock_t *lock);
 135 #else
 136 static inline void do_raw_spin_lock(raw_spinlock_t *lock)
 137 {
 138         arch_spin_lock(&lock->raw_lock);
 139 }
 140
 141 static inline void
 142 do_raw_spin_lock_flags(raw_spinlock_t *lock, unsigned long *flags)
 143 {
 144         arch_spin_lock_flags(&lock->raw_lock, *flags);
 145 }
 146
 147 static inline int do_raw_spin_trylock(raw_spinlock_t *lock)
 148 {
 149         return arch_spin_trylock(&(lock)->raw_lock);
 150 }
 151
 152 static inline void do_raw_spin_unlock(raw_spinlock_t *lock)
 153 {
 154         arch_spin_unlock(&lock->raw_lock);
 155 }
 156 #endif
 157
 158 /*
 159  * Define the various spin_lock methods.  Note we define these
 160  * regardless of whether CONFIG_SMP or CONFIG_PREEMPT are set. The
 161  * various methods are defined as nops in the case they are not
 162  * required.
 163  */
 164 #define raw_spin_trylock(lock)  __cond_lock(lock, _raw_spin_trylock(lock))
 165
 166 #define raw_spin_lock(lock)     _raw_spin_lock(lock)
 167
 168 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 169 # define raw_spin_lock_nested(lock, subclass) \
 170         _raw_spin_lock_nested(lock, subclass)
 171
 172 # define raw_spin_lock_nest_lock(lock, nest_lock)                       \
 173          do {                                                           \
 174                  typecheck(struct lockdep_map *, &(nest_lock)->dep_map);\
 175                  _raw_spin_lock_nest_lock(lock, &(nest_lock)->dep_map); \
 176          } while (0)
 177 #else
 178 # define raw_spin_lock_nested(lock, subclass)           _raw_spin_lock(lock)
 179 # define raw_spin_lock_nest_lock(lock, nest_lock)       _raw_spin_lock(lock)
 180 #endif
 181
 182 #if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
 183
 184 #define raw_spin_lock_irqsave(lock, flags)                      \
 185         do {                                            \
 186                 typecheck(unsigned long, flags);        \
 187                 flags = _raw_spin_lock_irqsave(lock);   \
 188         } while (0)
 189
 190 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 191 #define raw_spin_lock_irqsave_nested(lock, flags, subclass)             \
 192         do {                                                            \
 193                 typecheck(unsigned long, flags);                        \
 194                 flags = _raw_spin_lock_irqsave_nested(lock, subclass);  \
 195         } while (0)
 196 #else
 197 #define raw_spin_lock_irqsave_nested(lock, flags, subclass)             \
 198         do {                                                            \
 199                 typecheck(unsigned long, flags);                        \
 200                 flags = _raw_spin_lock_irqsave(lock);                   \
 201         } while (0)
 202 #endif
 203
 204 #else
 205
 206 #define raw_spin_lock_irqsave(lock, flags)              \
 207         do {                                            \
 208                 typecheck(unsigned long, flags);        \
 209                 _raw_spin_lock_irqsave(lock, flags);    \
 210         } while (0)
 211
 212 #define raw_spin_lock_irqsave_nested(lock, flags, subclass)     \
 213         raw_spin_lock_irqsave(lock, flags)
 214
 215 #endif
 216
 217 #define raw_spin_lock_irq(lock)         _raw_spin_lock_irq(lock)
 218 #define raw_spin_lock_bh(lock)          _raw_spin_lock_bh(lock)
 219 #define raw_spin_unlock(lock)           _raw_spin_unlock(lock)
 220 #define raw_spin_unlock_irq(lock)       _raw_spin_unlock_irq(lock)
 221
 222 #define raw_spin_unlock_irqrestore(lock, flags)         \
 223         do {                                                    \
 224                 typecheck(unsigned long, flags);                \
 225                 _raw_spin_unlock_irqrestore(lock, flags);       \
 226         } while (0)
 227 #define raw_spin_unlock_bh(lock)        _raw_spin_unlock_bh(lock)
 228
 229 #define raw_spin_trylock_bh(lock) \
 230         __cond_lock(lock, _raw_spin_trylock_bh(lock))
 231
 232 #define raw_spin_trylock_irq(lock) \
 233 ({ \
 234         local_irq_disable(); \
 235         raw_spin_trylock(lock) ? \
 236         1 : ({ local_irq_enable(); 0;  }); \
 237 })
 238
 239 #define raw_spin_trylock_irqsave(lock, flags) \
 240 ({ \
 241         local_irq_save(flags); \
 242         raw_spin_trylock(lock) ? \
 243         1 : ({ local_irq_restore(flags); 0; }); \
 244 })
 245
 246 /**
 247  * raw_spin_can_lock - would raw_spin_trylock() succeed?
 248  * @lock: the spinlock in question.
 249  */
 250 #define raw_spin_can_lock(lock) (!raw_spin_is_locked(lock))
 251
 252 /* Include rwlock functions */
 253 #include <linux/rwlock.h>
 254
 255 /*
 256  * Pull the _spin_*()/_read_*()/_write_*() functions/declarations:
 257  */
 258 #if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
 259 # include <linux/spinlock_api_smp.h>
 260 #else
 261 # include <linux/spinlock_api_up.h>
 262 #endif
 263
 264 /*
 265  * Map the spin_lock functions to the raw variants for PREEMPT_RT=n
 266  */
 267
 268 static inline raw_spinlock_t *spinlock_check(spinlock_t *lock)
 269 {
 270         return &lock->rlock;
 271 }
 272
 273 #define spin_lock_init(_lock)                           \
 274 do {                                                    \
 275         spinlock_check(_lock);                          \
 276         raw_spin_lock_init(&(_lock)->rlock);            \
 277 } while (0)
 278
 279 static inline void spin_lock(spinlock_t *lock)
 280 {
 281         raw_spin_lock(&lock->rlock);
 282 }
 283
 284 static inline void spin_lock_bh(spinlock_t *lock)
 285 {
 286         raw_spin_lock_bh(&lock->rlock);
 287 }
 288
 289 static inline int spin_trylock(spinlock_t *lock)
 290 {
 291         return raw_spin_trylock(&lock->rlock);
 292 }
 293
 294 #define spin_lock_nested(lock, subclass)                        \
 295 do {                                                            \
 296         raw_spin_lock_nested(spinlock_check(lock), subclass);   \
 297 } while (0)
 298
 299 #define spin_lock_nest_lock(lock, nest_lock)                            \
 300 do {                                                                    \
 301         raw_spin_lock_nest_lock(spinlock_check(lock), nest_lock);       \
 302 } while (0)
 303
 304 static inline void spin_lock_irq(spinlock_t *lock)
 305 {
 306         raw_spin_lock_irq(&lock->rlock);
 307 }
 308
 309 #define spin_lock_irqsave(lock, flags)                          \
 310 do {                                                            \
 311         raw_spin_lock_irqsave(spinlock_check(lock), flags);     \
 312 } while (0)
 313
 314 #define spin_lock_irqsave_nested(lock, flags, subclass)                 \
 315 do {                                                                    \
 316         raw_spin_lock_irqsave_nested(spinlock_check(lock), flags, subclass); \
 317 } while (0)
 318
 319 static inline void spin_unlock(spinlock_t *lock)
 320 {
 321         raw_spin_unlock(&lock->rlock);
 322 }
 323
 324 static inline void spin_unlock_bh(spinlock_t *lock)
 325 {
 326         raw_spin_unlock_bh(&lock->rlock);
 327 }
 328
 329 static inline void spin_unlock_irq(spinlock_t *lock)
 330 {
 331         raw_spin_unlock_irq(&lock->rlock);
 332 }
 333
 334 static inline void spin_unlock_irqrestore(spinlock_t *lock, unsigned long flags)
 335 {
 336         raw_spin_unlock_irqrestore(&lock->rlock, flags);
 337 }
 338
 339 static inline int spin_trylock_bh(spinlock_t *lock)
 340 {
 341         return raw_spin_trylock_bh(&lock->rlock);
 342 }
 343
 344 static inline int spin_trylock_irq(spinlock_t *lock)
 345 {
 346         return raw_spin_trylock_irq(&lock->rlock);
 347 }
 348
 349 #define spin_trylock_irqsave(lock, flags)                       \
 350 ({                                                              \
 351         raw_spin_trylock_irqsave(spinlock_check(lock), flags); \
 352 })
 353
 354 static inline void spin_unlock_wait(spinlock_t *lock)
 355 {
 356         raw_spin_unlock_wait(&lock->rlock);
 357 }
 358
 359 static inline int spin_is_locked(spinlock_t *lock)
 360 {
 361         return raw_spin_is_locked(&lock->rlock);
 362 }
 363
 364 static inline int spin_is_contended(spinlock_t *lock)
 365 {
 366         return raw_spin_is_contended(&lock->rlock);
 367 }
 368
 369 static inline int spin_can_lock(spinlock_t *lock)
 370 {
 371         return raw_spin_can_lock(&lock->rlock);
 372 }
 373
 374 static inline void assert_spin_locked(spinlock_t *lock)
 375 {
 376         assert_raw_spin_locked(&lock->rlock);
 377 }
 378
 379 /*
 380  * Pull the atomic_t declaration:
 381  * (asm-mips/atomic.h needs above definitions)
 382  */
 383 #include <asm/atomic.h>
 384 /**
 385  * atomic_dec_and_lock - lock on reaching reference count zero
 386  * @atomic: the atomic counter
 387  * @lock: the spinlock in question
 388  *
 389  * Decrements @atomic by 1.  If the result is 0, returns true and locks
 390  * @lock.  Returns false for all other cases.
 391  */
 392 extern int _atomic_dec_and_lock(atomic_t *atomic, spinlock_t *lock);
 393 #define atomic_dec_and_lock(atomic, lock) \
 394                 __cond_lock(lock, _atomic_dec_and_lock(atomic, lock))
 395
 396 #endif /* __LINUX_SPINLOCK_H */