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 #include <asm/system.h>
  61
  62 /*
  63  * Must define these before including other files, inline functions need them
  64  */
  65 #define LOCK_SECTION_NAME ".text..lock."KBUILD_BASENAME
  66
  67 #define LOCK_SECTION_START(extra)               \
  68         ".subsection 1\n\t"                     \
  69         extra                                   \
  70         ".ifndef " LOCK_SECTION_NAME "\n\t"     \
  71         LOCK_SECTION_NAME ":\n\t"               \
  72         ".endif\n"
  73
  74 #define LOCK_SECTION_END                        \
  75         ".previous\n\t"
  76
  77 #define __lockfunc __attribute__((section(".spinlock.text")))
  78
  79 /*
  80  * Pull the arch_spinlock_t and arch_rwlock_t definitions:
  81  */
  82 #include <linux/spinlock_types.h>
  83
  84 /*
  85  * Pull the arch_spin*() functions/declarations (UP-nondebug doesn't 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 __raw_spin_lock_init(raw_spinlock_t *lock, const char *name,
  95                                    struct lock_class_key *key);
  96 # define raw_spin_lock_init(lock)                               \
  97 do {                                                            \
  98         static struct lock_class_key __key;                     \
  99                                                                 \
 100         __raw_spin_lock_init((lock), #lock, &__key);            \
 101 } while (0)
 102
 103 #else
 104 # define raw_spin_lock_init(lock)                               \
 105         do { *(lock) = __RAW_SPIN_LOCK_UNLOCKED(lock); } while (0)
 106 #endif
 107
 108 #define raw_spin_is_locked(lock)        arch_spin_is_locked(&(lock)->raw_lock)
 109
 110 #ifdef CONFIG_GENERIC_LOCKBREAK
 111 #define raw_spin_is_contended(lock) ((lock)->break_lock)
 112 #else
 113
 114 #ifdef arch_spin_is_contended
 115 #define raw_spin_is_contended(lock)     arch_spin_is_contended(&(lock)->raw_lock)
 116 #else
 117 #define raw_spin_is_contended(lock)     (((void)(lock), 0))
 118 #endif /*arch_spin_is_contended*/
 119 #endif
 120
 121 /* The lock does not imply full memory barrier. */
 122 #ifndef ARCH_HAS_SMP_MB_AFTER_LOCK
 123 static inline void smp_mb__after_lock(void) { smp_mb(); }
 124 #endif
 125
 126 /**
 127  * raw_spin_unlock_wait - wait until the spinlock gets unlocked
 128  * @lock: the spinlock in question.
 129  */
 130 #define raw_spin_unlock_wait(lock)      arch_spin_unlock_wait(&(lock)->raw_lock)
 131
 132 #ifdef CONFIG_DEBUG_SPINLOCK
 133  extern void do_raw_spin_lock(raw_spinlock_t *lock) __acquires(lock);
 134 #define do_raw_spin_lock_flags(lock, flags) do_raw_spin_lock(lock)
 135  extern int do_raw_spin_trylock(raw_spinlock_t *lock);
 136  extern void do_raw_spin_unlock(raw_spinlock_t *lock) __releases(lock);
 137 #else
 138 static inline void do_raw_spin_lock(raw_spinlock_t *lock) __acquires(lock)
 139 {
 140         __acquire(lock);
 141         arch_spin_lock(&lock->raw_lock);
 142 }
 143
 144 static inline void
 145 do_raw_spin_lock_flags(raw_spinlock_t *lock, unsigned long *flags) __acquires(lock)
 146 {
 147         __acquire(lock);
 148         arch_spin_lock_flags(&lock->raw_lock, *flags);
 149 }
 150
 151 static inline int do_raw_spin_trylock(raw_spinlock_t *lock)
 152 {
 153         return arch_spin_trylock(&(lock)->raw_lock);
 154 }
 155
 156 static inline void do_raw_spin_unlock(raw_spinlock_t *lock) __releases(lock)
 157 {
 158         arch_spin_unlock(&lock->raw_lock);
 159         __release(lock);
 160 }
 161 #endif
 162
 163 /*
 164  * Define the various spin_lock methods.  Note we define these
 165  * regardless of whether CONFIG_SMP or CONFIG_PREEMPT are set. The
 166  * various methods are defined as nops in the case they are not
 167  * required.
 168  */
 169 #define raw_spin_trylock(lock)  __cond_lock(lock, _raw_spin_trylock(lock))
 170
 171 #define raw_spin_lock(lock)     _raw_spin_lock(lock)
 172
 173 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 174 # define raw_spin_lock_nested(lock, subclass) \
 175         _raw_spin_lock_nested(lock, subclass)
 176
 177 # define raw_spin_lock_nest_lock(lock, nest_lock)                       \
 178          do {                                                           \
 179                  typecheck(struct lockdep_map *, &(nest_lock)->dep_map);\
 180                  _raw_spin_lock_nest_lock(lock, &(nest_lock)->dep_map); \
 181          } while (0)
 182 #else
 183 # define raw_spin_lock_nested(lock, subclass)           _raw_spin_lock(lock)
 184 # define raw_spin_lock_nest_lock(lock, nest_lock)       _raw_spin_lock(lock)
 185 #endif
 186
 187 #if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
 188
 189 #define raw_spin_lock_irqsave(lock, flags)                      \
 190         do {                                            \
 191                 typecheck(unsigned long, flags);        \
 192                 flags = _raw_spin_lock_irqsave(lock);   \
 193         } while (0)
 194
 195 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 196 #define raw_spin_lock_irqsave_nested(lock, flags, subclass)             \
 197         do {                                                            \
 198                 typecheck(unsigned long, flags);                        \
 199                 flags = _raw_spin_lock_irqsave_nested(lock, subclass);  \
 200         } while (0)
 201 #else
 202 #define raw_spin_lock_irqsave_nested(lock, flags, subclass)             \
 203         do {                                                            \
 204                 typecheck(unsigned long, flags);                        \
 205                 flags = _raw_spin_lock_irqsave(lock);                   \
 206         } while (0)
 207 #endif
 208
 209 #else
 210
 211 #define raw_spin_lock_irqsave(lock, flags)              \
 212         do {                                            \
 213                 typecheck(unsigned long, flags);        \
 214                 _raw_spin_lock_irqsave(lock, flags);    \
 215         } while (0)
 216
 217 #define raw_spin_lock_irqsave_nested(lock, flags, subclass)     \
 218         raw_spin_lock_irqsave(lock, flags)
 219
 220 #endif
 221
 222 #define raw_spin_lock_irq(lock)         _raw_spin_lock_irq(lock)
 223 #define raw_spin_lock_bh(lock)          _raw_spin_lock_bh(lock)
 224 #define raw_spin_unlock(lock)           _raw_spin_unlock(lock)
 225 #define raw_spin_unlock_irq(lock)       _raw_spin_unlock_irq(lock)
 226
 227 #define raw_spin_unlock_irqrestore(lock, flags)         \
 228         do {                                                    \
 229                 typecheck(unsigned long, flags);                \
 230                 _raw_spin_unlock_irqrestore(lock, flags);       \
 231         } while (0)
 232 #define raw_spin_unlock_bh(lock)        _raw_spin_unlock_bh(lock)
 233
 234 #define raw_spin_trylock_bh(lock) \
 235         __cond_lock(lock, _raw_spin_trylock_bh(lock))
 236
 237 #define raw_spin_trylock_irq(lock) \
 238 ({ \
 239         local_irq_disable(); \
 240         raw_spin_trylock(lock) ? \
 241         1 : ({ local_irq_enable(); 0;  }); \
 242 })
 243
 244 #define raw_spin_trylock_irqsave(lock, flags) \
 245 ({ \
 246         local_irq_save(flags); \
 247         raw_spin_trylock(lock) ? \
 248         1 : ({ local_irq_restore(flags); 0; }); \
 249 })
 250
 251 /**
 252  * raw_spin_can_lock - would raw_spin_trylock() succeed?
 253  * @lock: the spinlock in question.
 254  */
 255 #define raw_spin_can_lock(lock) (!raw_spin_is_locked(lock))
 256
 257 /* Include rwlock functions */
 258 #include <linux/rwlock.h>
 259
 260 /*
 261  * Pull the _spin_*()/_read_*()/_write_*() functions/declarations:
 262  */
 263 #if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
 264 # include <linux/spinlock_api_smp.h>
 265 #else
 266 # include <linux/spinlock_api_up.h>
 267 #endif
 268
 269 /*
 270  * Map the spin_lock functions to the raw variants for PREEMPT_RT=n
 271  */
 272
 273 static inline raw_spinlock_t *spinlock_check(spinlock_t *lock)
 274 {
 275         return &lock->rlock;
 276 }
 277
 278 #define spin_lock_init(_lock)                           \
 279 do {                                                    \
 280         spinlock_check(_lock);                          \
 281         raw_spin_lock_init(&(_lock)->rlock);            \
 282 } while (0)
 283
 284 static inline void spin_lock(spinlock_t *lock)
 285 {
 286         raw_spin_lock(&lock->rlock);
 287 }
 288
 289 static inline void spin_lock_bh(spinlock_t *lock)
 290 {
 291         raw_spin_lock_bh(&lock->rlock);
 292 }
 293
 294 static inline int spin_trylock(spinlock_t *lock)
 295 {
 296         return raw_spin_trylock(&lock->rlock);
 297 }
 298
 299 #define spin_lock_nested(lock, subclass)                        \
 300 do {                                                            \
 301         raw_spin_lock_nested(spinlock_check(lock), subclass);   \
 302 } while (0)
 303
 304 #define spin_lock_nest_lock(lock, nest_lock)                            \
 305 do {                                                                    \
 306         raw_spin_lock_nest_lock(spinlock_check(lock), nest_lock);       \
 307 } while (0)
 308
 309 static inline void spin_lock_irq(spinlock_t *lock)
 310 {
 311         raw_spin_lock_irq(&lock->rlock);
 312 }
 313
 314 #define spin_lock_irqsave(lock, flags)                          \
 315 do {                                                            \
 316         raw_spin_lock_irqsave(spinlock_check(lock), flags);     \
 317 } while (0)
 318
 319 #define spin_lock_irqsave_nested(lock, flags, subclass)                 \
 320 do {                                                                    \
 321         raw_spin_lock_irqsave_nested(spinlock_check(lock), flags, subclass); \
 322 } while (0)
 323
 324 static inline void spin_unlock(spinlock_t *lock)
 325 {
 326         raw_spin_unlock(&lock->rlock);
 327 }
 328
 329 static inline void spin_unlock_bh(spinlock_t *lock)
 330 {
 331         raw_spin_unlock_bh(&lock->rlock);
 332 }
 333
 334 static inline void spin_unlock_irq(spinlock_t *lock)
 335 {
 336         raw_spin_unlock_irq(&lock->rlock);
 337 }
 338
 339 static inline void spin_unlock_irqrestore(spinlock_t *lock, unsigned long flags)
 340 {
 341         raw_spin_unlock_irqrestore(&lock->rlock, flags);
 342 }
 343
 344 static inline int spin_trylock_bh(spinlock_t *lock)
 345 {
 346         return raw_spin_trylock_bh(&lock->rlock);
 347 }
 348
 349 static inline int spin_trylock_irq(spinlock_t *lock)
 350 {
 351         return raw_spin_trylock_irq(&lock->rlock);
 352 }
 353
 354 #define spin_trylock_irqsave(lock, flags)                       \
 355 ({                                                              \
 356         raw_spin_trylock_irqsave(spinlock_check(lock), flags); \
 357 })
 358
 359 static inline void spin_unlock_wait(spinlock_t *lock)
 360 {
 361         raw_spin_unlock_wait(&lock->rlock);
 362 }
 363
 364 static inline int spin_is_locked(spinlock_t *lock)
 365 {
 366         return raw_spin_is_locked(&lock->rlock);
 367 }
 368
 369 static inline int spin_is_contended(spinlock_t *lock)
 370 {
 371         return raw_spin_is_contended(&lock->rlock);
 372 }
 373
 374 static inline int spin_can_lock(spinlock_t *lock)
 375 {
 376         return raw_spin_can_lock(&lock->rlock);
 377 }
 378
 379 static inline void assert_spin_locked(spinlock_t *lock)
 380 {
 381         assert_raw_spin_locked(&lock->rlock);
 382 }
 383
 384 /*
 385  * Pull the atomic_t declaration:
 386  * (asm-mips/atomic.h needs above definitions)
 387  */
 388 #include <linux/atomic.h>
 389 /**
 390  * atomic_dec_and_lock - lock on reaching reference count zero
 391  * @atomic: the atomic counter
 392  * @lock: the spinlock in question
 393  *
 394  * Decrements @atomic by 1.  If the result is 0, returns true and locks
 395  * @lock.  Returns false for all other cases.
 396  */
 397 extern int _atomic_dec_and_lock(atomic_t *atomic, spinlock_t *lock);
 398 #define atomic_dec_and_lock(atomic, lock) \
 399                 __cond_lock(lock, _atomic_dec_and_lock(atomic, lock))
 400
 401 #endif /* __LINUX_SPINLOCK_H */