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/irqflags.h>
  54 #include <linux/thread_info.h>
  55 #include <linux/kernel.h>
  56 #include <linux/stringify.h>
  57 #include <linux/bottom_half.h>
  58 #include <asm/barrier.h>
  59
  60
  61 /*
  62  * Must define these before including other files, inline functions need them
  63  */
  64 #define LOCK_SECTION_NAME ".text..lock."KBUILD_BASENAME
  65
  66 #define LOCK_SECTION_START(extra)               \
  67         ".subsection 1\n\t"                     \
  68         extra                                   \
  69         ".ifndef " LOCK_SECTION_NAME "\n\t"     \
  70         LOCK_SECTION_NAME ":\n\t"               \
  71         ".endif\n"
  72
  73 #define LOCK_SECTION_END                        \
  74         ".previous\n\t"
  75
  76 #define __lockfunc __attribute__((section(".spinlock.text")))
  77
  78 /*
  79  * Pull the arch_spinlock_t and arch_rwlock_t definitions:
  80  */
  81 #include <linux/spinlock_types.h>
  82
  83 /*
  84  * Pull the arch_spin*() functions/declarations (UP-nondebug doesn't need them):
  85  */
  86 #ifdef CONFIG_SMP
  87 # include <asm/spinlock.h>
  88 #else
  89 # include <linux/spinlock_up.h>
  90 #endif
  91
  92 #ifdef CONFIG_DEBUG_SPINLOCK
  93   extern void __raw_spin_lock_init(raw_spinlock_t *lock, const char *name,
  94                                    struct lock_class_key *key);
  95 # define raw_spin_lock_init(lock)                               \
  96 do {                                                            \
  97         static struct lock_class_key __key;                     \
  98                                                                 \
  99         __raw_spin_lock_init((lock), #lock, &__key);            \
 100 } while (0)
 101
 102 #else
 103 # define raw_spin_lock_init(lock)                               \
 104         do { *(lock) = __RAW_SPIN_LOCK_UNLOCKED(lock); } while (0)
 105 #endif
 106
 107 #define raw_spin_is_locked(lock)        arch_spin_is_locked(&(lock)->raw_lock)
 108
 109 #ifdef CONFIG_GENERIC_LOCKBREAK
 110 #define raw_spin_is_contended(lock) ((lock)->break_lock)
 111 #else
 112
 113 #ifdef arch_spin_is_contended
 114 #define raw_spin_is_contended(lock)     arch_spin_is_contended(&(lock)->raw_lock)
 115 #else
 116 #define raw_spin_is_contended(lock)     (((void)(lock), 0))
 117 #endif /*arch_spin_is_contended*/
 118 #endif
 119
 120 /* The lock does not imply full memory barrier. */
 121 #ifndef ARCH_HAS_SMP_MB_AFTER_LOCK
 122 static inline void smp_mb__after_lock(void) { smp_mb(); }
 123 #endif
 124
 125 /**
 126  * raw_spin_unlock_wait - wait until the spinlock gets unlocked
 127  * @lock: the spinlock in question.
 128  */
 129 #define raw_spin_unlock_wait(lock)      arch_spin_unlock_wait(&(lock)->raw_lock)
 130
 131 #ifdef CONFIG_DEBUG_SPINLOCK
 132  extern void do_raw_spin_lock(raw_spinlock_t *lock) __acquires(lock);
 133 #define do_raw_spin_lock_flags(lock, flags) do_raw_spin_lock(lock)
 134  extern int do_raw_spin_trylock(raw_spinlock_t *lock);
 135  extern void do_raw_spin_unlock(raw_spinlock_t *lock) __releases(lock);
 136 #else
 137 static inline void do_raw_spin_lock(raw_spinlock_t *lock) __acquires(lock)
 138 {
 139         __acquire(lock);
 140         arch_spin_lock(&lock->raw_lock);
 141 }
 142
 143 static inline void
 144 do_raw_spin_lock_flags(raw_spinlock_t *lock, unsigned long *flags) __acquires(lock)
 145 {
 146         __acquire(lock);
 147         arch_spin_lock_flags(&lock->raw_lock, *flags);
 148 }
 149
 150 static inline int do_raw_spin_trylock(raw_spinlock_t *lock)
 151 {
 152         return arch_spin_trylock(&(lock)->raw_lock);
 153 }
 154
 155 static inline void do_raw_spin_unlock(raw_spinlock_t *lock) __releases(lock)
 156 {
 157         arch_spin_unlock(&lock->raw_lock);
 158         __release(lock);
 159 }
 160 #endif
 161
 162 /*
 163  * Define the various spin_lock methods.  Note we define these
 164  * regardless of whether CONFIG_SMP or CONFIG_PREEMPT are set. The
 165  * various methods are defined as nops in the case they are not
 166  * required.
 167  */
 168 #define raw_spin_trylock(lock)  __cond_lock(lock, _raw_spin_trylock(lock))
 169
 170 #define raw_spin_lock(lock)     _raw_spin_lock(lock)
 171
 172 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 173 # define raw_spin_lock_nested(lock, subclass) \
 174         _raw_spin_lock_nested(lock, subclass)
 175
 176 # define raw_spin_lock_nest_lock(lock, nest_lock)                       \
 177          do {                                                           \
 178                  typecheck(struct lockdep_map *, &(nest_lock)->dep_map);\
 179                  _raw_spin_lock_nest_lock(lock, &(nest_lock)->dep_map); \
 180          } while (0)
 181 #else
 182 # define raw_spin_lock_nested(lock, subclass)           _raw_spin_lock(lock)
 183 # define raw_spin_lock_nest_lock(lock, nest_lock)       _raw_spin_lock(lock)
 184 #endif
 185
 186 #if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
 187
 188 #define raw_spin_lock_irqsave(lock, flags)                      \
 189         do {                                            \
 190                 typecheck(unsigned long, flags);        \
 191                 flags = _raw_spin_lock_irqsave(lock);   \
 192         } while (0)
 193
 194 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 195 #define raw_spin_lock_irqsave_nested(lock, flags, subclass)             \
 196         do {                                                            \
 197                 typecheck(unsigned long, flags);                        \
 198                 flags = _raw_spin_lock_irqsave_nested(lock, subclass);  \
 199         } while (0)
 200 #else
 201 #define raw_spin_lock_irqsave_nested(lock, flags, subclass)             \
 202         do {                                                            \
 203                 typecheck(unsigned long, flags);                        \
 204                 flags = _raw_spin_lock_irqsave(lock);                   \
 205         } while (0)
 206 #endif
 207
 208 #else
 209
 210 #define raw_spin_lock_irqsave(lock, flags)              \
 211         do {                                            \
 212                 typecheck(unsigned long, flags);        \
 213                 _raw_spin_lock_irqsave(lock, flags);    \
 214         } while (0)
 215
 216 #define raw_spin_lock_irqsave_nested(lock, flags, subclass)     \
 217         raw_spin_lock_irqsave(lock, flags)
 218
 219 #endif
 220
 221 #define raw_spin_lock_irq(lock)         _raw_spin_lock_irq(lock)
 222 #define raw_spin_lock_bh(lock)          _raw_spin_lock_bh(lock)
 223 #define raw_spin_unlock(lock)           _raw_spin_unlock(lock)
 224 #define raw_spin_unlock_irq(lock)       _raw_spin_unlock_irq(lock)
 225
 226 #define raw_spin_unlock_irqrestore(lock, flags)         \
 227         do {                                                    \
 228                 typecheck(unsigned long, flags);                \
 229                 _raw_spin_unlock_irqrestore(lock, flags);       \
 230         } while (0)
 231 #define raw_spin_unlock_bh(lock)        _raw_spin_unlock_bh(lock)
 232
 233 #define raw_spin_trylock_bh(lock) \
 234         __cond_lock(lock, _raw_spin_trylock_bh(lock))
 235
 236 #define raw_spin_trylock_irq(lock) \
 237 ({ \
 238         local_irq_disable(); \
 239         raw_spin_trylock(lock) ? \
 240         1 : ({ local_irq_enable(); 0;  }); \
 241 })
 242
 243 #define raw_spin_trylock_irqsave(lock, flags) \
 244 ({ \
 245         local_irq_save(flags); \
 246         raw_spin_trylock(lock) ? \
 247         1 : ({ local_irq_restore(flags); 0; }); \
 248 })
 249
 250 /**
 251  * raw_spin_can_lock - would raw_spin_trylock() succeed?
 252  * @lock: the spinlock in question.
 253  */
 254 #define raw_spin_can_lock(lock) (!raw_spin_is_locked(lock))
 255
 256 /* Include rwlock functions */
 257 #include <linux/rwlock.h>
 258
 259 /*
 260  * Pull the _spin_*()/_read_*()/_write_*() functions/declarations:
 261  */
 262 #if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
 263 # include <linux/spinlock_api_smp.h>
 264 #else
 265 # include <linux/spinlock_api_up.h>
 266 #endif
 267
 268 /*
 269  * Map the spin_lock functions to the raw variants for PREEMPT_RT=n
 270  */
 271
 272 static inline raw_spinlock_t *spinlock_check(spinlock_t *lock)
 273 {
 274         return &lock->rlock;
 275 }
 276
 277 #define spin_lock_init(_lock)                           \
 278 do {                                                    \
 279         spinlock_check(_lock);                          \
 280         raw_spin_lock_init(&(_lock)->rlock);            \
 281 } while (0)
 282
 283 static inline void spin_lock(spinlock_t *lock)
 284 {
 285         raw_spin_lock(&lock->rlock);
 286 }
 287
 288 static inline void spin_lock_bh(spinlock_t *lock)
 289 {
 290         raw_spin_lock_bh(&lock->rlock);
 291 }
 292
 293 static inline int spin_trylock(spinlock_t *lock)
 294 {
 295         return raw_spin_trylock(&lock->rlock);
 296 }
 297
 298 #define spin_lock_nested(lock, subclass)                        \
 299 do {                                                            \
 300         raw_spin_lock_nested(spinlock_check(lock), subclass);   \
 301 } while (0)
 302
 303 #define spin_lock_nest_lock(lock, nest_lock)                            \
 304 do {                                                                    \
 305         raw_spin_lock_nest_lock(spinlock_check(lock), nest_lock);       \
 306 } while (0)
 307
 308 static inline void spin_lock_irq(spinlock_t *lock)
 309 {
 310         raw_spin_lock_irq(&lock->rlock);
 311 }
 312
 313 #define spin_lock_irqsave(lock, flags)                          \
 314 do {                                                            \
 315         raw_spin_lock_irqsave(spinlock_check(lock), flags);     \
 316 } while (0)
 317
 318 #define spin_lock_irqsave_nested(lock, flags, subclass)                 \
 319 do {                                                                    \
 320         raw_spin_lock_irqsave_nested(spinlock_check(lock), flags, subclass); \
 321 } while (0)
 322
 323 static inline void spin_unlock(spinlock_t *lock)
 324 {
 325         raw_spin_unlock(&lock->rlock);
 326 }
 327
 328 static inline void spin_unlock_bh(spinlock_t *lock)
 329 {
 330         raw_spin_unlock_bh(&lock->rlock);
 331 }
 332
 333 static inline void spin_unlock_irq(spinlock_t *lock)
 334 {
 335         raw_spin_unlock_irq(&lock->rlock);
 336 }
 337
 338 static inline void spin_unlock_irqrestore(spinlock_t *lock, unsigned long flags)
 339 {
 340         raw_spin_unlock_irqrestore(&lock->rlock, flags);
 341 }
 342
 343 static inline int spin_trylock_bh(spinlock_t *lock)
 344 {
 345         return raw_spin_trylock_bh(&lock->rlock);
 346 }
 347
 348 static inline int spin_trylock_irq(spinlock_t *lock)
 349 {
 350         return raw_spin_trylock_irq(&lock->rlock);
 351 }
 352
 353 #define spin_trylock_irqsave(lock, flags)                       \
 354 ({                                                              \
 355         raw_spin_trylock_irqsave(spinlock_check(lock), flags); \
 356 })
 357
 358 static inline void spin_unlock_wait(spinlock_t *lock)
 359 {
 360         raw_spin_unlock_wait(&lock->rlock);
 361 }
 362
 363 static inline int spin_is_locked(spinlock_t *lock)
 364 {
 365         return raw_spin_is_locked(&lock->rlock);
 366 }
 367
 368 static inline int spin_is_contended(spinlock_t *lock)
 369 {
 370         return raw_spin_is_contended(&lock->rlock);
 371 }
 372
 373 static inline int spin_can_lock(spinlock_t *lock)
 374 {
 375         return raw_spin_can_lock(&lock->rlock);
 376 }
 377
 378 #define assert_spin_locked(lock)        assert_raw_spin_locked(&(lock)->rlock)
 379
 380 /*
 381  * Pull the atomic_t declaration:
 382  * (asm-mips/atomic.h needs above definitions)
 383  */
 384 #include <linux/atomic.h>
 385 /**
 386  * atomic_dec_and_lock - lock on reaching reference count zero
 387  * @atomic: the atomic counter
 388  * @lock: the spinlock in question
 389  *
 390  * Decrements @atomic by 1.  If the result is 0, returns true and locks
 391  * @lock.  Returns false for all other cases.
 392  */
 393 extern int _atomic_dec_and_lock(atomic_t *atomic, spinlock_t *lock);
 394 #define atomic_dec_and_lock(atomic, lock) \
 395                 __cond_lock(lock, _atomic_dec_and_lock(atomic, lock))
 396
 397 #endif /* __LINUX_SPINLOCK_H */