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/preempt.h>
  50#include <linux/linkage.h>
  51#include <linux/compiler.h>
  52#include <linux/thread_info.h>
  53#include <linux/kernel.h>
  54#include <linux/stringify.h>
  55
  56#include <asm/system.h>
  57
  58/*
  59 * Must define these before including other files, inline functions need them
  60 */
  61#define LOCK_SECTION_NAME ".text.lock."KBUILD_BASENAME
  62
  63#define LOCK_SECTION_START(extra)               \
  64        ".subsection 1\n\t"                     \
  65        extra                                   \
  66        ".ifndef " LOCK_SECTION_NAME "\n\t"     \
  67        LOCK_SECTION_NAME ":\n\t"               \
  68        ".endif\n"
  69
  70#define LOCK_SECTION_END                        \
  71        ".previous\n\t"
  72
  73#define __lockfunc fastcall __attribute__((section(".spinlock.text")))
  74
  75/*
  76 * Pull the raw_spinlock_t and raw_rwlock_t definitions:
  77 */
  78#include <linux/spinlock_types.h>
  79
  80extern int __lockfunc generic__raw_read_trylock(raw_rwlock_t *lock);
  81
  82/*
  83 * Pull the __raw*() 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 __spin_lock_init(spinlock_t *lock, const char *name,
  93                               struct lock_class_key *key);
  94# define spin_lock_init(lock)                                   \
  95do {                                                            \
  96        static struct lock_class_key __key;                     \
  97                                                                \
  98        __spin_lock_init((lock), #lock, &__key);                \
  99} while (0)
 100
 101#else
 102# define spin_lock_init(lock)                                   \
 103        do { *(lock) = SPIN_LOCK_UNLOCKED; } while (0)
 104#endif
 105
 106#ifdef CONFIG_DEBUG_SPINLOCK
 107  extern void __rwlock_init(rwlock_t *lock, const char *name,
 108                            struct lock_class_key *key);
 109# define rwlock_init(lock)                                      \
 110do {                                                            \
 111        static struct lock_class_key __key;                     \
 112                                                                \
 113        __rwlock_init((lock), #lock, &__key);                   \
 114} while (0)
 115#else
 116# define rwlock_init(lock)                                      \
 117        do { *(lock) = RW_LOCK_UNLOCKED; } while (0)
 118#endif
 119
 120#define spin_is_locked(lock)    __raw_spin_is_locked(&(lock)->raw_lock)
 121
 122/**
 123 * spin_unlock_wait - wait until the spinlock gets unlocked
 124 * @lock: the spinlock in question.
 125 */
 126#define spin_unlock_wait(lock)  __raw_spin_unlock_wait(&(lock)->raw_lock)
 127
 128/*
 129 * Pull the _spin_*()/_read_*()/_write_*() functions/declarations:
 130 */
 131#if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
 132# include <linux/spinlock_api_smp.h>
 133#else
 134# include <linux/spinlock_api_up.h>
 135#endif
 136
 137#ifdef CONFIG_DEBUG_SPINLOCK
 138 extern void _raw_spin_lock(spinlock_t *lock);
 139#define _raw_spin_lock_flags(lock, flags) _raw_spin_lock(lock)
 140 extern int _raw_spin_trylock(spinlock_t *lock);
 141 extern void _raw_spin_unlock(spinlock_t *lock);
 142 extern void _raw_read_lock(rwlock_t *lock);
 143 extern int _raw_read_trylock(rwlock_t *lock);
 144 extern void _raw_read_unlock(rwlock_t *lock);
 145 extern void _raw_write_lock(rwlock_t *lock);
 146 extern int _raw_write_trylock(rwlock_t *lock);
 147 extern void _raw_write_unlock(rwlock_t *lock);
 148#else
 149# define _raw_spin_lock(lock)           __raw_spin_lock(&(lock)->raw_lock)
 150# define _raw_spin_lock_flags(lock, flags) \
 151                __raw_spin_lock_flags(&(lock)->raw_lock, *(flags))
 152# define _raw_spin_trylock(lock)        __raw_spin_trylock(&(lock)->raw_lock)
 153# define _raw_spin_unlock(lock)         __raw_spin_unlock(&(lock)->raw_lock)
 154# define _raw_read_lock(rwlock)         __raw_read_lock(&(rwlock)->raw_lock)
 155# define _raw_read_trylock(rwlock)      __raw_read_trylock(&(rwlock)->raw_lock)
 156# define _raw_read_unlock(rwlock)       __raw_read_unlock(&(rwlock)->raw_lock)
 157# define _raw_write_lock(rwlock)        __raw_write_lock(&(rwlock)->raw_lock)
 158# define _raw_write_trylock(rwlock)     __raw_write_trylock(&(rwlock)->raw_lock)
 159# define _raw_write_unlock(rwlock)      __raw_write_unlock(&(rwlock)->raw_lock)
 160#endif
 161
 162#define read_can_lock(rwlock)           __raw_read_can_lock(&(rwlock)->raw_lock)
 163#define write_can_lock(rwlock)          __raw_write_can_lock(&(rwlock)->raw_lock)
 164
 165/*
 166 * Define the various spin_lock and rw_lock methods.  Note we define these
 167 * regardless of whether CONFIG_SMP or CONFIG_PREEMPT are set. The various
 168 * methods are defined as nops in the case they are not required.
 169 */
 170#define spin_trylock(lock)              __cond_lock(_spin_trylock(lock))
 171#define read_trylock(lock)              __cond_lock(_read_trylock(lock))
 172#define write_trylock(lock)             __cond_lock(_write_trylock(lock))
 173
 174#define spin_lock(lock)                 _spin_lock(lock)
 175
 176#ifdef CONFIG_DEBUG_LOCK_ALLOC
 177# define spin_lock_nested(lock, subclass) _spin_lock_nested(lock, subclass)
 178#else
 179# define spin_lock_nested(lock, subclass) _spin_lock(lock)
 180#endif
 181
 182#define write_lock(lock)                _write_lock(lock)
 183#define read_lock(lock)                 _read_lock(lock)
 184
 185#if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
 186#define spin_lock_irqsave(lock, flags)  flags = _spin_lock_irqsave(lock)
 187#define read_lock_irqsave(lock, flags)  flags = _read_lock_irqsave(lock)
 188#define write_lock_irqsave(lock, flags) flags = _write_lock_irqsave(lock)
 189#else
 190#define spin_lock_irqsave(lock, flags)  _spin_lock_irqsave(lock, flags)
 191#define read_lock_irqsave(lock, flags)  _read_lock_irqsave(lock, flags)
 192#define write_lock_irqsave(lock, flags) _write_lock_irqsave(lock, flags)
 193#endif
 194
 195#define spin_lock_irq(lock)             _spin_lock_irq(lock)
 196#define spin_lock_bh(lock)              _spin_lock_bh(lock)
 197
 198#define read_lock_irq(lock)             _read_lock_irq(lock)
 199#define read_lock_bh(lock)              _read_lock_bh(lock)
 200
 201#define write_lock_irq(lock)            _write_lock_irq(lock)
 202#define write_lock_bh(lock)             _write_lock_bh(lock)
 203
 204/*
 205 * We inline the unlock functions in the nondebug case:
 206 */
 207#if defined(CONFIG_DEBUG_SPINLOCK) || defined(CONFIG_PREEMPT) || \
 208        !defined(CONFIG_SMP)
 209# define spin_unlock(lock)              _spin_unlock(lock)
 210# define read_unlock(lock)              _read_unlock(lock)
 211# define write_unlock(lock)             _write_unlock(lock)
 212# define spin_unlock_irq(lock)          _spin_unlock_irq(lock)
 213# define read_unlock_irq(lock)          _read_unlock_irq(lock)
 214# define write_unlock_irq(lock)         _write_unlock_irq(lock)
 215#else
 216# define spin_unlock(lock)              __raw_spin_unlock(&(lock)->raw_lock)
 217# define read_unlock(lock)              __raw_read_unlock(&(lock)->raw_lock)
 218# define write_unlock(lock)             __raw_write_unlock(&(lock)->raw_lock)
 219# define spin_unlock_irq(lock) \
 220    do { __raw_spin_unlock(&(lock)->raw_lock); local_irq_enable(); } while (0)
 221# define read_unlock_irq(lock) \
 222    do { __raw_read_unlock(&(lock)->raw_lock); local_irq_enable(); } while (0)
 223# define write_unlock_irq(lock) \
 224    do { __raw_write_unlock(&(lock)->raw_lock); local_irq_enable(); } while (0)
 225#endif
 226
 227#define spin_unlock_irqrestore(lock, flags) \
 228                                        _spin_unlock_irqrestore(lock, flags)
 229#define spin_unlock_bh(lock)            _spin_unlock_bh(lock)
 230
 231#define read_unlock_irqrestore(lock, flags) \
 232                                        _read_unlock_irqrestore(lock, flags)
 233#define read_unlock_bh(lock)            _read_unlock_bh(lock)
 234
 235#define write_unlock_irqrestore(lock, flags) \
 236                                        _write_unlock_irqrestore(lock, flags)
 237#define write_unlock_bh(lock)           _write_unlock_bh(lock)
 238
 239#define spin_trylock_bh(lock)           __cond_lock(_spin_trylock_bh(lock))
 240
 241#define spin_trylock_irq(lock) \
 242({ \
 243        local_irq_disable(); \
 244        _spin_trylock(lock) ? \
 245        1 : ({ local_irq_enable(); 0;  }); \
 246})
 247
 248#define spin_trylock_irqsave(lock, flags) \
 249({ \
 250        local_irq_save(flags); \
 251        _spin_trylock(lock) ? \
 252        1 : ({ local_irq_restore(flags); 0; }); \
 253})
 254
 255/*
 256 * Pull the atomic_t declaration:
 257 * (asm-mips/atomic.h needs above definitions)
 258 */
 259#include <asm/atomic.h>
 260/**
 261 * atomic_dec_and_lock - lock on reaching reference count zero
 262 * @atomic: the atomic counter
 263 * @lock: the spinlock in question
 264 */
 265extern int _atomic_dec_and_lock(atomic_t *atomic, spinlock_t *lock);
 266#define atomic_dec_and_lock(atomic, lock) \
 267                __cond_lock(_atomic_dec_and_lock(atomic, lock))
 268
 269/**
 270 * spin_can_lock - would spin_trylock() succeed?
 271 * @lock: the spinlock in question.
 272 */
 273#define spin_can_lock(lock)     (!spin_is_locked(lock))
 274
 275#endif /* __LINUX_SPINLOCK_H */
 276
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