linux/include/linux/spinlock.h
<<
>>
Prefs
   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
 128#ifdef __raw_spin_is_contended
 129#define spin_is_contended(lock) __raw_spin_is_contended(&(lock)->raw_lock)
 130#else
 131#define spin_is_contended(lock) (((void)(lock), 0))
 132#endif /*__raw_spin_is_contended*/
 133#endif
 134
 135/**
 136 * spin_unlock_wait - wait until the spinlock gets unlocked
 137 * @lock: the spinlock in question.
 138 */
 139#define spin_unlock_wait(lock)  __raw_spin_unlock_wait(&(lock)->raw_lock)
 140
 141/*
 142 * Pull the _spin_*()/_read_*()/_write_*() functions/declarations:
 143 */
 144#if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
 145# include <linux/spinlock_api_smp.h>
 146#else
 147# include <linux/spinlock_api_up.h>
 148#endif
 149
 150#ifdef CONFIG_DEBUG_SPINLOCK
 151 extern void _raw_spin_lock(spinlock_t *lock);
 152#define _raw_spin_lock_flags(lock, flags) _raw_spin_lock(lock)
 153 extern int _raw_spin_trylock(spinlock_t *lock);
 154 extern void _raw_spin_unlock(spinlock_t *lock);
 155 extern void _raw_read_lock(rwlock_t *lock);
 156 extern int _raw_read_trylock(rwlock_t *lock);
 157 extern void _raw_read_unlock(rwlock_t *lock);
 158 extern void _raw_write_lock(rwlock_t *lock);
 159 extern int _raw_write_trylock(rwlock_t *lock);
 160 extern void _raw_write_unlock(rwlock_t *lock);
 161#else
 162# define _raw_spin_lock(lock)           __raw_spin_lock(&(lock)->raw_lock)
 163# define _raw_spin_lock_flags(lock, flags) \
 164                __raw_spin_lock_flags(&(lock)->raw_lock, *(flags))
 165# define _raw_spin_trylock(lock)        __raw_spin_trylock(&(lock)->raw_lock)
 166# define _raw_spin_unlock(lock)         __raw_spin_unlock(&(lock)->raw_lock)
 167# define _raw_read_lock(rwlock)         __raw_read_lock(&(rwlock)->raw_lock)
 168# define _raw_read_trylock(rwlock)      __raw_read_trylock(&(rwlock)->raw_lock)
 169# define _raw_read_unlock(rwlock)       __raw_read_unlock(&(rwlock)->raw_lock)
 170# define _raw_write_lock(rwlock)        __raw_write_lock(&(rwlock)->raw_lock)
 171# define _raw_write_trylock(rwlock)     __raw_write_trylock(&(rwlock)->raw_lock)
 172# define _raw_write_unlock(rwlock)      __raw_write_unlock(&(rwlock)->raw_lock)
 173#endif
 174
 175#define read_can_lock(rwlock)           __raw_read_can_lock(&(rwlock)->raw_lock)
 176#define write_can_lock(rwlock)          __raw_write_can_lock(&(rwlock)->raw_lock)
 177
 178/*
 179 * Define the various spin_lock and rw_lock methods.  Note we define these
 180 * regardless of whether CONFIG_SMP or CONFIG_PREEMPT are set. The various
 181 * methods are defined as nops in the case they are not required.
 182 */
 183#define spin_trylock(lock)              __cond_lock(lock, _spin_trylock(lock))
 184#define read_trylock(lock)              __cond_lock(lock, _read_trylock(lock))
 185#define write_trylock(lock)             __cond_lock(lock, _write_trylock(lock))
 186
 187#define spin_lock(lock)                 _spin_lock(lock)
 188
 189#ifdef CONFIG_DEBUG_LOCK_ALLOC
 190# define spin_lock_nested(lock, subclass) _spin_lock_nested(lock, subclass)
 191# define spin_lock_nest_lock(lock, nest_lock)                           \
 192         do {                                                           \
 193                 typecheck(struct lockdep_map *, &(nest_lock)->dep_map);\
 194                 _spin_lock_nest_lock(lock, &(nest_lock)->dep_map);     \
 195         } while (0)
 196#else
 197# define spin_lock_nested(lock, subclass) _spin_lock(lock)
 198# define spin_lock_nest_lock(lock, nest_lock) _spin_lock(lock)
 199#endif
 200
 201#define write_lock(lock)                _write_lock(lock)
 202#define read_lock(lock)                 _read_lock(lock)
 203
 204#if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
 205
 206#define spin_lock_irqsave(lock, flags)                  \
 207        do {                                            \
 208                typecheck(unsigned long, flags);        \
 209                flags = _spin_lock_irqsave(lock);       \
 210        } while (0)
 211#define read_lock_irqsave(lock, flags)                  \
 212        do {                                            \
 213                typecheck(unsigned long, flags);        \
 214                flags = _read_lock_irqsave(lock);       \
 215        } while (0)
 216#define write_lock_irqsave(lock, flags)                 \
 217        do {                                            \
 218                typecheck(unsigned long, flags);        \
 219                flags = _write_lock_irqsave(lock);      \
 220        } while (0)
 221
 222#ifdef CONFIG_DEBUG_LOCK_ALLOC
 223#define spin_lock_irqsave_nested(lock, flags, subclass)                 \
 224        do {                                                            \
 225                typecheck(unsigned long, flags);                        \
 226                flags = _spin_lock_irqsave_nested(lock, subclass);      \
 227        } while (0)
 228#else
 229#define spin_lock_irqsave_nested(lock, flags, subclass)                 \
 230        do {                                                            \
 231                typecheck(unsigned long, flags);                        \
 232                flags = _spin_lock_irqsave(lock);                       \
 233        } while (0)
 234#endif
 235
 236#else
 237
 238#define spin_lock_irqsave(lock, flags)                  \
 239        do {                                            \
 240                typecheck(unsigned long, flags);        \
 241                _spin_lock_irqsave(lock, flags);        \
 242        } while (0)
 243#define read_lock_irqsave(lock, flags)                  \
 244        do {                                            \
 245                typecheck(unsigned long, flags);        \
 246                _read_lock_irqsave(lock, flags);        \
 247        } while (0)
 248#define write_lock_irqsave(lock, flags)                 \
 249        do {                                            \
 250                typecheck(unsigned long, flags);        \
 251                _write_lock_irqsave(lock, flags);       \
 252        } while (0)
 253#define spin_lock_irqsave_nested(lock, flags, subclass) \
 254        spin_lock_irqsave(lock, flags)
 255
 256#endif
 257
 258#define spin_lock_irq(lock)             _spin_lock_irq(lock)
 259#define spin_lock_bh(lock)              _spin_lock_bh(lock)
 260
 261#define read_lock_irq(lock)             _read_lock_irq(lock)
 262#define read_lock_bh(lock)              _read_lock_bh(lock)
 263
 264#define write_lock_irq(lock)            _write_lock_irq(lock)
 265#define write_lock_bh(lock)             _write_lock_bh(lock)
 266
 267/*
 268 * We inline the unlock functions in the nondebug case:
 269 */
 270#if defined(CONFIG_DEBUG_SPINLOCK) || defined(CONFIG_PREEMPT) || \
 271        !defined(CONFIG_SMP)
 272# define spin_unlock(lock)              _spin_unlock(lock)
 273# define read_unlock(lock)              _read_unlock(lock)
 274# define write_unlock(lock)             _write_unlock(lock)
 275# define spin_unlock_irq(lock)          _spin_unlock_irq(lock)
 276# define read_unlock_irq(lock)          _read_unlock_irq(lock)
 277# define write_unlock_irq(lock)         _write_unlock_irq(lock)
 278#else
 279# define spin_unlock(lock) \
 280    do {__raw_spin_unlock(&(lock)->raw_lock); __release(lock); } while (0)
 281# define read_unlock(lock) \
 282    do {__raw_read_unlock(&(lock)->raw_lock); __release(lock); } while (0)
 283# define write_unlock(lock) \
 284    do {__raw_write_unlock(&(lock)->raw_lock); __release(lock); } while (0)
 285# define spin_unlock_irq(lock)                  \
 286do {                                            \
 287        __raw_spin_unlock(&(lock)->raw_lock);   \
 288        __release(lock);                        \
 289        local_irq_enable();                     \
 290} while (0)
 291# define read_unlock_irq(lock)                  \
 292do {                                            \
 293        __raw_read_unlock(&(lock)->raw_lock);   \
 294        __release(lock);                        \
 295        local_irq_enable();                     \
 296} while (0)
 297# define write_unlock_irq(lock)                 \
 298do {                                            \
 299        __raw_write_unlock(&(lock)->raw_lock);  \
 300        __release(lock);                        \
 301        local_irq_enable();                     \
 302} while (0)
 303#endif
 304
 305#define spin_unlock_irqrestore(lock, flags)             \
 306        do {                                            \
 307                typecheck(unsigned long, flags);        \
 308                _spin_unlock_irqrestore(lock, flags);   \
 309        } while (0)
 310#define spin_unlock_bh(lock)            _spin_unlock_bh(lock)
 311
 312#define read_unlock_irqrestore(lock, flags)             \
 313        do {                                            \
 314                typecheck(unsigned long, flags);        \
 315                _read_unlock_irqrestore(lock, flags);   \
 316        } while (0)
 317#define read_unlock_bh(lock)            _read_unlock_bh(lock)
 318
 319#define write_unlock_irqrestore(lock, flags)            \
 320        do {                                            \
 321                typecheck(unsigned long, flags);        \
 322                _write_unlock_irqrestore(lock, flags);  \
 323        } while (0)
 324#define write_unlock_bh(lock)           _write_unlock_bh(lock)
 325
 326#define spin_trylock_bh(lock)   __cond_lock(lock, _spin_trylock_bh(lock))
 327
 328#define spin_trylock_irq(lock) \
 329({ \
 330        local_irq_disable(); \
 331        spin_trylock(lock) ? \
 332        1 : ({ local_irq_enable(); 0;  }); \
 333})
 334
 335#define spin_trylock_irqsave(lock, flags) \
 336({ \
 337        local_irq_save(flags); \
 338        spin_trylock(lock) ? \
 339        1 : ({ local_irq_restore(flags); 0; }); \
 340})
 341
 342#define write_trylock_irqsave(lock, flags) \
 343({ \
 344        local_irq_save(flags); \
 345        write_trylock(lock) ? \
 346        1 : ({ local_irq_restore(flags); 0; }); \
 347})
 348
 349/*
 350 * Pull the atomic_t declaration:
 351 * (asm-mips/atomic.h needs above definitions)
 352 */
 353#include <asm/atomic.h>
 354/**
 355 * atomic_dec_and_lock - lock on reaching reference count zero
 356 * @atomic: the atomic counter
 357 * @lock: the spinlock in question
 358 *
 359 * Decrements @atomic by 1.  If the result is 0, returns true and locks
 360 * @lock.  Returns false for all other cases.
 361 */
 362extern int _atomic_dec_and_lock(atomic_t *atomic, spinlock_t *lock);
 363#define atomic_dec_and_lock(atomic, lock) \
 364                __cond_lock(lock, _atomic_dec_and_lock(atomic, lock))
 365
 366/**
 367 * spin_can_lock - would spin_trylock() succeed?
 368 * @lock: the spinlock in question.
 369 */
 370#define spin_can_lock(lock)     (!spin_is_locked(lock))
 371
 372#endif /* __LINUX_SPINLOCK_H */
 373
lxr.linux.no kindly hosted by Redpill Linpro AS, provider of Linux consulting and operations services since 1995.