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 raw_spinlock_t/raw_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 __raw_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 __raw_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 raw_spinlock_t and raw_rwlock_t definitions:
  79 */
  80#include <linux/spinlock_types.h>
  81
  82extern int __lockfunc generic__raw_read_trylock(raw_rwlock_t *lock);
  83
  84/*
  85 * Pull the __raw*() functions/declarations (UP-nondebug doesnt 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 __spin_lock_init(spinlock_t *lock, const char *name,
  95                               struct lock_class_key *key);
  96# define spin_lock_init(lock)                                   \
  97do {                                                            \
  98        static struct lock_class_key __key;                     \
  99                                                                \
 100        __spin_lock_init((lock), #lock, &__key);                \
 101} while (0)
 102
 103#else
 104# define spin_lock_init(lock)                                   \
 105        do { *(lock) = SPIN_LOCK_UNLOCKED; } while (0)
 106#endif
 107
 108#ifdef CONFIG_DEBUG_SPINLOCK
 109  extern void __rwlock_init(rwlock_t *lock, const char *name,
 110                            struct lock_class_key *key);
 111# define rwlock_init(lock)                                      \
 112do {                                                            \
 113        static struct lock_class_key __key;                     \
 114                                                                \
 115        __rwlock_init((lock), #lock, &__key);                   \
 116} while (0)
 117#else
 118# define rwlock_init(lock)                                      \
 119        do { *(lock) = RW_LOCK_UNLOCKED; } while (0)
 120#endif
 121
 122#define spin_is_locked(lock)    __raw_spin_is_locked(&(lock)->raw_lock)
 123
 124#ifdef CONFIG_GENERIC_LOCKBREAK
 125#define spin_is_contended(lock) ((lock)->break_lock)
 126#else
 127#define spin_is_contended(lock) __raw_spin_is_contended(&(lock)->raw_lock)
 128#endif
 129
 130/**
 131 * spin_unlock_wait - wait until the spinlock gets unlocked
 132 * @lock: the spinlock in question.
 133 */
 134#define spin_unlock_wait(lock)  __raw_spin_unlock_wait(&(lock)->raw_lock)
 135
 136/*
 137 * Pull the _spin_*()/_read_*()/_write_*() functions/declarations:
 138 */
 139#if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
 140# include <linux/spinlock_api_smp.h>
 141#else
 142# include <linux/spinlock_api_up.h>
 143#endif
 144
 145#ifdef CONFIG_DEBUG_SPINLOCK
 146 extern void _raw_spin_lock(spinlock_t *lock);
 147#define _raw_spin_lock_flags(lock, flags) _raw_spin_lock(lock)
 148 extern int _raw_spin_trylock(spinlock_t *lock);
 149 extern void _raw_spin_unlock(spinlock_t *lock);
 150 extern void _raw_read_lock(rwlock_t *lock);
 151 extern int _raw_read_trylock(rwlock_t *lock);
 152 extern void _raw_read_unlock(rwlock_t *lock);
 153 extern void _raw_write_lock(rwlock_t *lock);
 154 extern int _raw_write_trylock(rwlock_t *lock);
 155 extern void _raw_write_unlock(rwlock_t *lock);
 156#else
 157# define _raw_spin_lock(lock)           __raw_spin_lock(&(lock)->raw_lock)
 158# define _raw_spin_lock_flags(lock, flags) \
 159                __raw_spin_lock_flags(&(lock)->raw_lock, *(flags))
 160# define _raw_spin_trylock(lock)        __raw_spin_trylock(&(lock)->raw_lock)
 161# define _raw_spin_unlock(lock)         __raw_spin_unlock(&(lock)->raw_lock)
 162# define _raw_read_lock(rwlock)         __raw_read_lock(&(rwlock)->raw_lock)
 163# define _raw_read_trylock(rwlock)      __raw_read_trylock(&(rwlock)->raw_lock)
 164# define _raw_read_unlock(rwlock)       __raw_read_unlock(&(rwlock)->raw_lock)
 165# define _raw_write_lock(rwlock)        __raw_write_lock(&(rwlock)->raw_lock)
 166# define _raw_write_trylock(rwlock)     __raw_write_trylock(&(rwlock)->raw_lock)
 167# define _raw_write_unlock(rwlock)      __raw_write_unlock(&(rwlock)->raw_lock)
 168#endif
 169
 170#define read_can_lock(rwlock)           __raw_read_can_lock(&(rwlock)->raw_lock)
 171#define write_can_lock(rwlock)          __raw_write_can_lock(&(rwlock)->raw_lock)
 172
 173/*
 174 * Define the various spin_lock and rw_lock methods.  Note we define these
 175 * regardless of whether CONFIG_SMP or CONFIG_PREEMPT are set. The various
 176 * methods are defined as nops in the case they are not required.
 177 */
 178#define spin_trylock(lock)              __cond_lock(lock, _spin_trylock(lock))
 179#define read_trylock(lock)              __cond_lock(lock, _read_trylock(lock))
 180#define write_trylock(lock)             __cond_lock(lock, _write_trylock(lock))
 181
 182#define spin_lock(lock)                 _spin_lock(lock)
 183
 184#ifdef CONFIG_DEBUG_LOCK_ALLOC
 185# define spin_lock_nested(lock, subclass) _spin_lock_nested(lock, subclass)
 186# define spin_lock_nest_lock(lock, nest_lock)                           \
 187         do {                                                           \
 188                 typecheck(struct lockdep_map *, &(nest_lock)->dep_map);\
 189                 _spin_lock_nest_lock(lock, &(nest_lock)->dep_map);     \
 190         } while (0)
 191#else
 192# define spin_lock_nested(lock, subclass) _spin_lock(lock)
 193# define spin_lock_nest_lock(lock, nest_lock) _spin_lock(lock)
 194#endif
 195
 196#define write_lock(lock)                _write_lock(lock)
 197#define read_lock(lock)                 _read_lock(lock)
 198
 199#if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
 200
 201#define spin_lock_irqsave(lock, flags)                  \
 202        do {                                            \
 203                typecheck(unsigned long, flags);        \
 204                flags = _spin_lock_irqsave(lock);       \
 205        } while (0)
 206#define read_lock_irqsave(lock, flags)                  \
 207        do {                                            \
 208                typecheck(unsigned long, flags);        \
 209                flags = _read_lock_irqsave(lock);       \
 210        } while (0)
 211#define write_lock_irqsave(lock, flags)                 \
 212        do {                                            \
 213                typecheck(unsigned long, flags);        \
 214                flags = _write_lock_irqsave(lock);      \
 215        } while (0)
 216
 217#ifdef CONFIG_DEBUG_LOCK_ALLOC
 218#define spin_lock_irqsave_nested(lock, flags, subclass)                 \
 219        do {                                                            \
 220                typecheck(unsigned long, flags);                        \
 221                flags = _spin_lock_irqsave_nested(lock, subclass);      \
 222        } while (0)
 223#else
 224#define spin_lock_irqsave_nested(lock, flags, subclass)                 \
 225        do {                                                            \
 226                typecheck(unsigned long, flags);                        \
 227                flags = _spin_lock_irqsave(lock);                       \
 228        } while (0)
 229#endif
 230
 231#else
 232
 233#define spin_lock_irqsave(lock, flags)                  \
 234        do {                                            \
 235                typecheck(unsigned long, flags);        \
 236                _spin_lock_irqsave(lock, flags);        \
 237        } while (0)
 238#define read_lock_irqsave(lock, flags)                  \
 239        do {                                            \
 240                typecheck(unsigned long, flags);        \
 241                _read_lock_irqsave(lock, flags);        \
 242        } while (0)
 243#define write_lock_irqsave(lock, flags)                 \
 244        do {                                            \
 245                typecheck(unsigned long, flags);        \
 246                _write_lock_irqsave(lock, flags);       \
 247        } while (0)
 248#define spin_lock_irqsave_nested(lock, flags, subclass) \
 249        spin_lock_irqsave(lock, flags)
 250
 251#endif
 252
 253#define spin_lock_irq(lock)             _spin_lock_irq(lock)
 254#define spin_lock_bh(lock)              _spin_lock_bh(lock)
 255
 256#define read_lock_irq(lock)             _read_lock_irq(lock)
 257#define read_lock_bh(lock)              _read_lock_bh(lock)
 258
 259#define write_lock_irq(lock)            _write_lock_irq(lock)
 260#define write_lock_bh(lock)             _write_lock_bh(lock)
 261
 262/*
 263 * We inline the unlock functions in the nondebug case:
 264 */
 265#if defined(CONFIG_DEBUG_SPINLOCK) || defined(CONFIG_PREEMPT) || \
 266        !defined(CONFIG_SMP)
 267# define spin_unlock(lock)              _spin_unlock(lock)
 268# define read_unlock(lock)              _read_unlock(lock)
 269# define write_unlock(lock)             _write_unlock(lock)
 270# define spin_unlock_irq(lock)          _spin_unlock_irq(lock)
 271# define read_unlock_irq(lock)          _read_unlock_irq(lock)
 272# define write_unlock_irq(lock)         _write_unlock_irq(lock)
 273#else
 274# define spin_unlock(lock) \
 275    do {__raw_spin_unlock(&(lock)->raw_lock); __release(lock); } while (0)
 276# define read_unlock(lock) \
 277    do {__raw_read_unlock(&(lock)->raw_lock); __release(lock); } while (0)
 278# define write_unlock(lock) \
 279    do {__raw_write_unlock(&(lock)->raw_lock); __release(lock); } while (0)
 280# define spin_unlock_irq(lock)                  \
 281do {                                            \
 282        __raw_spin_unlock(&(lock)->raw_lock);   \
 283        __release(lock);                        \
 284        local_irq_enable();                     \
 285} while (0)
 286# define read_unlock_irq(lock)                  \
 287do {                                            \
 288        __raw_read_unlock(&(lock)->raw_lock);   \
 289        __release(lock);                        \
 290        local_irq_enable();                     \
 291} while (0)
 292# define write_unlock_irq(lock)                 \
 293do {                                            \
 294        __raw_write_unlock(&(lock)->raw_lock);  \
 295        __release(lock);                        \
 296        local_irq_enable();                     \
 297} while (0)
 298#endif
 299
 300#define spin_unlock_irqrestore(lock, flags)             \
 301        do {                                            \
 302                typecheck(unsigned long, flags);        \
 303                _spin_unlock_irqrestore(lock, flags);   \
 304        } while (0)
 305#define spin_unlock_bh(lock)            _spin_unlock_bh(lock)
 306
 307#define read_unlock_irqrestore(lock, flags)             \
 308        do {                                            \
 309                typecheck(unsigned long, flags);        \
 310                _read_unlock_irqrestore(lock, flags);   \
 311        } while (0)
 312#define read_unlock_bh(lock)            _read_unlock_bh(lock)
 313
 314#define write_unlock_irqrestore(lock, flags)            \
 315        do {                                            \
 316                typecheck(unsigned long, flags);        \
 317                _write_unlock_irqrestore(lock, flags);  \
 318        } while (0)
 319#define write_unlock_bh(lock)           _write_unlock_bh(lock)
 320
 321#define spin_trylock_bh(lock)   __cond_lock(lock, _spin_trylock_bh(lock))
 322
 323#define spin_trylock_irq(lock) \
 324({ \
 325        local_irq_disable(); \
 326        spin_trylock(lock) ? \
 327        1 : ({ local_irq_enable(); 0;  }); \
 328})
 329
 330#define spin_trylock_irqsave(lock, flags) \
 331({ \
 332        local_irq_save(flags); \
 333        spin_trylock(lock) ? \
 334        1 : ({ local_irq_restore(flags); 0; }); \
 335})
 336
 337#define write_trylock_irqsave(lock, flags) \
 338({ \
 339        local_irq_save(flags); \
 340        write_trylock(lock) ? \
 341        1 : ({ local_irq_restore(flags); 0; }); \
 342})
 343
 344/*
 345 * Pull the atomic_t declaration:
 346 * (asm-mips/atomic.h needs above definitions)
 347 */
 348#include <asm/atomic.h>
 349/**
 350 * atomic_dec_and_lock - lock on reaching reference count zero
 351 * @atomic: the atomic counter
 352 * @lock: the spinlock in question
 353 *
 354 * Decrements @atomic by 1.  If the result is 0, returns true and locks
 355 * @lock.  Returns false for all other cases.
 356 */
 357extern int _atomic_dec_and_lock(atomic_t *atomic, spinlock_t *lock);
 358#define atomic_dec_and_lock(atomic, lock) \
 359                __cond_lock(lock, _atomic_dec_and_lock(atomic, lock))
 360
 361/**
 362 * spin_can_lock - would spin_trylock() succeed?
 363 * @lock: the spinlock in question.
 364 */
 365#define spin_can_lock(lock)     (!spin_is_locked(lock))
 366
 367#endif /* __LINUX_SPINLOCK_H */
 368
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