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);
 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
 136static inline void do_raw_spin_lock(raw_spinlock_t *lock)
 137{
 138        arch_spin_lock(&lock->raw_lock);
 139}
 140
 141static inline void
 142do_raw_spin_lock_flags(raw_spinlock_t *lock, unsigned long *flags)
 143{
 144        arch_spin_lock_flags(&lock->raw_lock, *flags);
 145}
 146
 147static inline int do_raw_spin_trylock(raw_spinlock_t *lock)
 148{
 149        return arch_spin_trylock(&(lock)->raw_lock);
 150}
 151
 152static 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
 268static inline raw_spinlock_t *spinlock_check(spinlock_t *lock)
 269{
 270        return &lock->rlock;
 271}
 272
 273#define spin_lock_init(_lock)                           \
 274do {                                                    \
 275        spinlock_check(_lock);                          \
 276        raw_spin_lock_init(&(_lock)->rlock);            \
 277} while (0)
 278
 279static inline void spin_lock(spinlock_t *lock)
 280{
 281        raw_spin_lock(&lock->rlock);
 282}
 283
 284static inline void spin_lock_bh(spinlock_t *lock)
 285{
 286        raw_spin_lock_bh(&lock->rlock);
 287}
 288
 289static inline int spin_trylock(spinlock_t *lock)
 290{
 291        return raw_spin_trylock(&lock->rlock);
 292}
 293
 294#define spin_lock_nested(lock, subclass)                        \
 295do {                                                            \
 296        raw_spin_lock_nested(spinlock_check(lock), subclass);   \
 297} while (0)
 298
 299#define spin_lock_nest_lock(lock, nest_lock)                            \
 300do {                                                                    \
 301        raw_spin_lock_nest_lock(spinlock_check(lock), nest_lock);       \
 302} while (0)
 303
 304static 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)                          \
 310do {                                                            \
 311        raw_spin_lock_irqsave(spinlock_check(lock), flags);     \
 312} while (0)
 313
 314#define spin_lock_irqsave_nested(lock, flags, subclass)                 \
 315do {                                                                    \
 316        raw_spin_lock_irqsave_nested(spinlock_check(lock), flags, subclass); \
 317} while (0)
 318
 319static inline void spin_unlock(spinlock_t *lock)
 320{
 321        raw_spin_unlock(&lock->rlock);
 322}
 323
 324static inline void spin_unlock_bh(spinlock_t *lock)
 325{
 326        raw_spin_unlock_bh(&lock->rlock);
 327}
 328
 329static inline void spin_unlock_irq(spinlock_t *lock)
 330{
 331        raw_spin_unlock_irq(&lock->rlock);
 332}
 333
 334static inline void spin_unlock_irqrestore(spinlock_t *lock, unsigned long flags)
 335{
 336        raw_spin_unlock_irqrestore(&lock->rlock, flags);
 337}
 338
 339static inline int spin_trylock_bh(spinlock_t *lock)
 340{
 341        return raw_spin_trylock_bh(&lock->rlock);
 342}
 343
 344static 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
 354static inline void spin_unlock_wait(spinlock_t *lock)
 355{
 356        raw_spin_unlock_wait(&lock->rlock);
 357}
 358
 359static inline int spin_is_locked(spinlock_t *lock)
 360{
 361        return raw_spin_is_locked(&lock->rlock);
 362}
 363
 364static inline int spin_is_contended(spinlock_t *lock)
 365{
 366        return raw_spin_is_contended(&lock->rlock);
 367}
 368
 369static inline int spin_can_lock(spinlock_t *lock)
 370{
 371        return raw_spin_can_lock(&lock->rlock);
 372}
 373
 374static 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 */
 392extern 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 */
 397
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