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) __acquires(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) __releases(lock);
 135 #else
 136 static inline void do_raw_spin_lock(raw_spinlock_t *lock) __acquires(lock)
 137 {
 138         __acquire(lock);
 139         arch_spin_lock(&lock->raw_lock);
 140 }
 141
 142 static inline void
 143 do_raw_spin_lock_flags(raw_spinlock_t *lock, unsigned long *flags) __acquires(lock)
 144 {
 145         __acquire(lock);
 146         arch_spin_lock_flags(&lock->raw_lock, *flags);
 147 }
 148
 149 static inline int do_raw_spin_trylock(raw_spinlock_t *lock)
 150 {
 151         return arch_spin_trylock(&(lock)->raw_lock);
 152 }
 153
 154 static inline void do_raw_spin_unlock(raw_spinlock_t *lock) __releases(lock)
 155 {
 156         arch_spin_unlock(&lock->raw_lock);
 157         __release(lock);
 158 }
 159 #endif
 160
 161 /*
 162  * Define the various spin_lock methods.  Note we define these
 163  * regardless of whether CONFIG_SMP or CONFIG_PREEMPT are set. The
 164  * various methods are defined as nops in the case they are not
 165  * required.
 166  */
 167 #define raw_spin_trylock(lock)  __cond_lock(lock, _raw_spin_trylock(lock))
 168
 169 #define raw_spin_lock(lock)     _raw_spin_lock(lock)
 170
 171 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 172 # define raw_spin_lock_nested(lock, subclass) \
 173         _raw_spin_lock_nested(lock, subclass)
 174
 175 # define raw_spin_lock_nest_lock(lock, nest_lock)                       \
 176          do {                                                           \
 177                  typecheck(struct lockdep_map *, &(nest_lock)->dep_map);\
 178                  _raw_spin_lock_nest_lock(lock, &(nest_lock)->dep_map); \
 179          } while (0)
 180 #else
 181 # define raw_spin_lock_nested(lock, subclass)           _raw_spin_lock(lock)
 182 # define raw_spin_lock_nest_lock(lock, nest_lock)       _raw_spin_lock(lock)
 183 #endif
 184
 185 #if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
 186
 187 #define raw_spin_lock_irqsave(lock, flags)                      \
 188         do {                                            \
 189                 typecheck(unsigned long, flags);        \
 190                 flags = _raw_spin_lock_irqsave(lock);   \
 191         } while (0)
 192
 193 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 194 #define raw_spin_lock_irqsave_nested(lock, flags, subclass)             \
 195         do {                                                            \
 196                 typecheck(unsigned long, flags);                        \
 197                 flags = _raw_spin_lock_irqsave_nested(lock, subclass);  \
 198         } while (0)
 199 #else
 200 #define raw_spin_lock_irqsave_nested(lock, flags, subclass)             \
 201         do {                                                            \
 202                 typecheck(unsigned long, flags);                        \
 203                 flags = _raw_spin_lock_irqsave(lock);                   \
 204         } while (0)
 205 #endif
 206
 207 #else
 208
 209 #define raw_spin_lock_irqsave(lock, flags)              \
 210         do {                                            \
 211                 typecheck(unsigned long, flags);        \
 212                 _raw_spin_lock_irqsave(lock, flags);    \
 213         } while (0)
 214
 215 #define raw_spin_lock_irqsave_nested(lock, flags, subclass)     \
 216         raw_spin_lock_irqsave(lock, flags)
 217
 218 #endif
 219
 220 #define raw_spin_lock_irq(lock)         _raw_spin_lock_irq(lock)
 221 #define raw_spin_lock_bh(lock)          _raw_spin_lock_bh(lock)
 222 #define raw_spin_unlock(lock)           _raw_spin_unlock(lock)
 223 #define raw_spin_unlock_irq(lock)       _raw_spin_unlock_irq(lock)
 224
 225 #define raw_spin_unlock_irqrestore(lock, flags)         \
 226         do {                                                    \
 227                 typecheck(unsigned long, flags);                \
 228                 _raw_spin_unlock_irqrestore(lock, flags);       \
 229         } while (0)
 230 #define raw_spin_unlock_bh(lock)        _raw_spin_unlock_bh(lock)
 231
 232 #define raw_spin_trylock_bh(lock) \
 233         __cond_lock(lock, _raw_spin_trylock_bh(lock))
 234
 235 #define raw_spin_trylock_irq(lock) \
 236 ({ \
 237         local_irq_disable(); \
 238         raw_spin_trylock(lock) ? \
 239         1 : ({ local_irq_enable(); 0;  }); \
 240 })
 241
 242 #define raw_spin_trylock_irqsave(lock, flags) \
 243 ({ \
 244         local_irq_save(flags); \
 245         raw_spin_trylock(lock) ? \
 246         1 : ({ local_irq_restore(flags); 0; }); \
 247 })
 248
 249 /**
 250  * raw_spin_can_lock - would raw_spin_trylock() succeed?
 251  * @lock: the spinlock in question.
 252  */
 253 #define raw_spin_can_lock(lock) (!raw_spin_is_locked(lock))
 254
 255 /* Include rwlock functions */
 256 #include <linux/rwlock.h>
 257
 258 /*
 259  * Pull the _spin_*()/_read_*()/_write_*() functions/declarations:
 260  */
 261 #if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
 262 # include <linux/spinlock_api_smp.h>
 263 #else
 264 # include <linux/spinlock_api_up.h>
 265 #endif
 266
 267 /*
 268  * Map the spin_lock functions to the raw variants for PREEMPT_RT=n
 269  */
 270
 271 static inline raw_spinlock_t *spinlock_check(spinlock_t *lock)
 272 {
 273         return &lock->rlock;
 274 }
 275
 276 #define spin_lock_init(_lock)                           \
 277 do {                                                    \
 278         spinlock_check(_lock);                          \
 279         raw_spin_lock_init(&(_lock)->rlock);            \
 280 } while (0)
 281
 282 static inline void spin_lock(spinlock_t *lock)
 283 {
 284         raw_spin_lock(&lock->rlock);
 285 }
 286
 287 static inline void spin_lock_bh(spinlock_t *lock)
 288 {
 289         raw_spin_lock_bh(&lock->rlock);
 290 }
 291
 292 static inline int spin_trylock(spinlock_t *lock)
 293 {
 294         return raw_spin_trylock(&lock->rlock);
 295 }
 296
 297 #define spin_lock_nested(lock, subclass)                        \
 298 do {                                                            \
 299         raw_spin_lock_nested(spinlock_check(lock), subclass);   \
 300 } while (0)
 301
 302 #define spin_lock_nest_lock(lock, nest_lock)                            \
 303 do {                                                                    \
 304         raw_spin_lock_nest_lock(spinlock_check(lock), nest_lock);       \
 305 } while (0)
 306
 307 static inline void spin_lock_irq(spinlock_t *lock)
 308 {
 309         raw_spin_lock_irq(&lock->rlock);
 310 }
 311
 312 #define spin_lock_irqsave(lock, flags)                          \
 313 do {                                                            \
 314         raw_spin_lock_irqsave(spinlock_check(lock), flags);     \
 315 } while (0)
 316
 317 #define spin_lock_irqsave_nested(lock, flags, subclass)                 \
 318 do {                                                                    \
 319         raw_spin_lock_irqsave_nested(spinlock_check(lock), flags, subclass); \
 320 } while (0)
 321
 322 static inline void spin_unlock(spinlock_t *lock)
 323 {
 324         raw_spin_unlock(&lock->rlock);
 325 }
 326
 327 static inline void spin_unlock_bh(spinlock_t *lock)
 328 {
 329         raw_spin_unlock_bh(&lock->rlock);
 330 }
 331
 332 static inline void spin_unlock_irq(spinlock_t *lock)
 333 {
 334         raw_spin_unlock_irq(&lock->rlock);
 335 }
 336
 337 static inline void spin_unlock_irqrestore(spinlock_t *lock, unsigned long flags)
 338 {
 339         raw_spin_unlock_irqrestore(&lock->rlock, flags);
 340 }
 341
 342 static inline int spin_trylock_bh(spinlock_t *lock)
 343 {
 344         return raw_spin_trylock_bh(&lock->rlock);
 345 }
 346
 347 static inline int spin_trylock_irq(spinlock_t *lock)
 348 {
 349         return raw_spin_trylock_irq(&lock->rlock);
 350 }
 351
 352 #define spin_trylock_irqsave(lock, flags)                       \
 353 ({                                                              \
 354         raw_spin_trylock_irqsave(spinlock_check(lock), flags); \
 355 })
 356
 357 static inline void spin_unlock_wait(spinlock_t *lock)
 358 {
 359         raw_spin_unlock_wait(&lock->rlock);
 360 }
 361
 362 static inline int spin_is_locked(spinlock_t *lock)
 363 {
 364         return raw_spin_is_locked(&lock->rlock);
 365 }
 366
 367 static inline int spin_is_contended(spinlock_t *lock)
 368 {
 369         return raw_spin_is_contended(&lock->rlock);
 370 }
 371
 372 static inline int spin_can_lock(spinlock_t *lock)
 373 {
 374         return raw_spin_can_lock(&lock->rlock);
 375 }
 376
 377 static inline void assert_spin_locked(spinlock_t *lock)
 378 {
 379         assert_raw_spin_locked(&lock->rlock);
 380 }
 381
 382 /*
 383  * Pull the atomic_t declaration:
 384  * (asm-mips/atomic.h needs above definitions)
 385  */
 386 #include <asm/atomic.h>
 387 /**
 388  * atomic_dec_and_lock - lock on reaching reference count zero
 389  * @atomic: the atomic counter
 390  * @lock: the spinlock in question
 391  *
 392  * Decrements @atomic by 1.  If the result is 0, returns true and locks
 393  * @lock.  Returns false for all other cases.
 394  */
 395 extern int _atomic_dec_and_lock(atomic_t *atomic, spinlock_t *lock);
 396 #define atomic_dec_and_lock(atomic, lock) \
 397                 __cond_lock(lock, _atomic_dec_and_lock(atomic, lock))
 398
 399 #endif /* __LINUX_SPINLOCK_H */