linux/include/linux/spinlock.h
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   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)                               \
  95do {                                                            \
  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
 121static 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
 136static 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
 142static inline void
 143do_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
 149static inline int do_raw_spin_trylock(raw_spinlock_t *lock)
 150{
 151        return arch_spin_trylock(&(lock)->raw_lock);
 152}
 153
 154static 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
 271static inline raw_spinlock_t *spinlock_check(spinlock_t *lock)
 272{
 273        return &lock->rlock;
 274}
 275
 276#define spin_lock_init(_lock)                           \
 277do {                                                    \
 278        spinlock_check(_lock);                          \
 279        raw_spin_lock_init(&(_lock)->rlock);            \
 280} while (0)
 281
 282static inline void spin_lock(spinlock_t *lock)
 283{
 284        raw_spin_lock(&lock->rlock);
 285}
 286
 287static inline void spin_lock_bh(spinlock_t *lock)
 288{
 289        raw_spin_lock_bh(&lock->rlock);
 290}
 291
 292static inline int spin_trylock(spinlock_t *lock)
 293{
 294        return raw_spin_trylock(&lock->rlock);
 295}
 296
 297#define spin_lock_nested(lock, subclass)                        \
 298do {                                                            \
 299        raw_spin_lock_nested(spinlock_check(lock), subclass);   \
 300} while (0)
 301
 302#define spin_lock_nest_lock(lock, nest_lock)                            \
 303do {                                                                    \
 304        raw_spin_lock_nest_lock(spinlock_check(lock), nest_lock);       \
 305} while (0)
 306
 307static 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)                          \
 313do {                                                            \
 314        raw_spin_lock_irqsave(spinlock_check(lock), flags);     \
 315} while (0)
 316
 317#define spin_lock_irqsave_nested(lock, flags, subclass)                 \
 318do {                                                                    \
 319        raw_spin_lock_irqsave_nested(spinlock_check(lock), flags, subclass); \
 320} while (0)
 321
 322static inline void spin_unlock(spinlock_t *lock)
 323{
 324        raw_spin_unlock(&lock->rlock);
 325}
 326
 327static inline void spin_unlock_bh(spinlock_t *lock)
 328{
 329        raw_spin_unlock_bh(&lock->rlock);
 330}
 331
 332static inline void spin_unlock_irq(spinlock_t *lock)
 333{
 334        raw_spin_unlock_irq(&lock->rlock);
 335}
 336
 337static inline void spin_unlock_irqrestore(spinlock_t *lock, unsigned long flags)
 338{
 339        raw_spin_unlock_irqrestore(&lock->rlock, flags);
 340}
 341
 342static inline int spin_trylock_bh(spinlock_t *lock)
 343{
 344        return raw_spin_trylock_bh(&lock->rlock);
 345}
 346
 347static 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
 357static inline void spin_unlock_wait(spinlock_t *lock)
 358{
 359        raw_spin_unlock_wait(&lock->rlock);
 360}
 361
 362static inline int spin_is_locked(spinlock_t *lock)
 363{
 364        return raw_spin_is_locked(&lock->rlock);
 365}
 366
 367static inline int spin_is_contended(spinlock_t *lock)
 368{
 369        return raw_spin_is_contended(&lock->rlock);
 370}
 371
 372static inline int spin_can_lock(spinlock_t *lock)
 373{
 374        return raw_spin_can_lock(&lock->rlock);
 375}
 376
 377static 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 */
 395extern 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 */
 400
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