include/linux/spinlock.h

   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
  80 extern 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 #if defined(CONFIG_SMP)
  86 # include <asm/spinlock.h>
  87 #else
  88 # include <linux/spinlock_up.h>
  89 #endif
  90
  91 #define spin_lock_init(lock)    do { *(lock) = SPIN_LOCK_UNLOCKED; } while (0)
  92 #define rwlock_init(lock)       do { *(lock) = RW_LOCK_UNLOCKED; } while (0)
  93
  94 #define spin_is_locked(lock)    __raw_spin_is_locked(&(lock)->raw_lock)
  95
  96 /**
  97  * spin_unlock_wait - wait until the spinlock gets unlocked
  98  * @lock: the spinlock in question.
  99  */
 100 #define spin_unlock_wait(lock)  __raw_spin_unlock_wait(&(lock)->raw_lock)
 101
 102 /*
 103  * Pull the _spin_*()/_read_*()/_write_*() functions/declarations:
 104  */
 105 #if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
 106 # include <linux/spinlock_api_smp.h>
 107 #else
 108 # include <linux/spinlock_api_up.h>
 109 #endif
 110
 111 #ifdef CONFIG_DEBUG_SPINLOCK
 112  extern void _raw_spin_lock(spinlock_t *lock);
 113 #define _raw_spin_lock_flags(lock, flags) _raw_spin_lock(lock)
 114  extern int _raw_spin_trylock(spinlock_t *lock);
 115  extern void _raw_spin_unlock(spinlock_t *lock);
 116
 117  extern void _raw_read_lock(rwlock_t *lock);
 118  extern int _raw_read_trylock(rwlock_t *lock);
 119  extern void _raw_read_unlock(rwlock_t *lock);
 120  extern void _raw_write_lock(rwlock_t *lock);
 121  extern int _raw_write_trylock(rwlock_t *lock);
 122  extern void _raw_write_unlock(rwlock_t *lock);
 123 #else
 124 # define _raw_spin_unlock(lock)         __raw_spin_unlock(&(lock)->raw_lock)
 125 # define _raw_spin_trylock(lock)        __raw_spin_trylock(&(lock)->raw_lock)
 126 # define _raw_spin_lock(lock)           __raw_spin_lock(&(lock)->raw_lock)
 127 # define _raw_spin_lock_flags(lock, flags) \
 128                 __raw_spin_lock_flags(&(lock)->raw_lock, *(flags))
 129 # define _raw_read_lock(rwlock)         __raw_read_lock(&(rwlock)->raw_lock)
 130 # define _raw_write_lock(rwlock)        __raw_write_lock(&(rwlock)->raw_lock)
 131 # define _raw_read_unlock(rwlock)       __raw_read_unlock(&(rwlock)->raw_lock)
 132 # define _raw_write_unlock(rwlock)      __raw_write_unlock(&(rwlock)->raw_lock)
 133 # define _raw_read_trylock(rwlock)      __raw_read_trylock(&(rwlock)->raw_lock)
 134 # define _raw_write_trylock(rwlock)     __raw_write_trylock(&(rwlock)->raw_lock)
 135 #endif
 136
 137 #define read_can_lock(rwlock)           __raw_read_can_lock(&(rwlock)->raw_lock)
 138 #define write_can_lock(rwlock)          __raw_write_can_lock(&(rwlock)->raw_lock)
 139
 140 /*
 141  * Define the various spin_lock and rw_lock methods.  Note we define these
 142  * regardless of whether CONFIG_SMP or CONFIG_PREEMPT are set. The various
 143  * methods are defined as nops in the case they are not required.
 144  */
 145 #define spin_trylock(lock)              __cond_lock(_spin_trylock(lock))
 146 #define read_trylock(lock)              __cond_lock(_read_trylock(lock))
 147 #define write_trylock(lock)             __cond_lock(_write_trylock(lock))
 148
 149 #define spin_lock(lock)                 _spin_lock(lock)
 150 #define write_lock(lock)                _write_lock(lock)
 151 #define read_lock(lock)                 _read_lock(lock)
 152
 153 #if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
 154 #define spin_lock_irqsave(lock, flags)  flags = _spin_lock_irqsave(lock)
 155 #define read_lock_irqsave(lock, flags)  flags = _read_lock_irqsave(lock)
 156 #define write_lock_irqsave(lock, flags) flags = _write_lock_irqsave(lock)
 157 #else
 158 #define spin_lock_irqsave(lock, flags)  _spin_lock_irqsave(lock, flags)
 159 #define read_lock_irqsave(lock, flags)  _read_lock_irqsave(lock, flags)
 160 #define write_lock_irqsave(lock, flags) _write_lock_irqsave(lock, flags)
 161 #endif
 162
 163 #define spin_lock_irq(lock)             _spin_lock_irq(lock)
 164 #define spin_lock_bh(lock)              _spin_lock_bh(lock)
 165
 166 #define read_lock_irq(lock)             _read_lock_irq(lock)
 167 #define read_lock_bh(lock)              _read_lock_bh(lock)
 168
 169 #define write_lock_irq(lock)            _write_lock_irq(lock)
 170 #define write_lock_bh(lock)             _write_lock_bh(lock)
 171
 172 /*
 173  * We inline the unlock functions in the nondebug case:
 174  */
 175 #if defined(CONFIG_DEBUG_SPINLOCK) || defined(CONFIG_PREEMPT) || !defined(CONFIG_SMP)
 176 # define spin_unlock(lock)              _spin_unlock(lock)
 177 # define read_unlock(lock)              _read_unlock(lock)
 178 # define write_unlock(lock)             _write_unlock(lock)
 179 #else
 180 # define spin_unlock(lock)              __raw_spin_unlock(&(lock)->raw_lock)
 181 # define read_unlock(lock)              __raw_read_unlock(&(lock)->raw_lock)
 182 # define write_unlock(lock)             __raw_write_unlock(&(lock)->raw_lock)
 183 #endif
 184
 185 #if defined(CONFIG_DEBUG_SPINLOCK) || defined(CONFIG_PREEMPT) || !defined(CONFIG_SMP)
 186 # define spin_unlock_irq(lock)          _spin_unlock_irq(lock)
 187 # define read_unlock_irq(lock)          _read_unlock_irq(lock)
 188 # define write_unlock_irq(lock)         _write_unlock_irq(lock)
 189 #else
 190 # define spin_unlock_irq(lock) \
 191     do { __raw_spin_unlock(&(lock)->raw_lock); local_irq_enable(); } while (0)
 192 # define read_unlock_irq(lock) \
 193     do { __raw_read_unlock(&(lock)->raw_lock); local_irq_enable(); } while (0)
 194 # define write_unlock_irq(lock) \
 195     do { __raw_write_unlock(&(lock)->raw_lock); local_irq_enable(); } while (0)
 196 #endif
 197
 198 #define spin_unlock_irqrestore(lock, flags) \
 199                                         _spin_unlock_irqrestore(lock, flags)
 200 #define spin_unlock_bh(lock)            _spin_unlock_bh(lock)
 201
 202 #define read_unlock_irqrestore(lock, flags) \
 203                                         _read_unlock_irqrestore(lock, flags)
 204 #define read_unlock_bh(lock)            _read_unlock_bh(lock)
 205
 206 #define write_unlock_irqrestore(lock, flags) \
 207                                         _write_unlock_irqrestore(lock, flags)
 208 #define write_unlock_bh(lock)           _write_unlock_bh(lock)
 209
 210 #define spin_trylock_bh(lock)           __cond_lock(_spin_trylock_bh(lock))
 211
 212 #define spin_trylock_irq(lock) \
 213 ({ \
 214         local_irq_disable(); \
 215         _spin_trylock(lock) ? \
 216         1 : ({ local_irq_enable(); 0;  }); \
 217 })
 218
 219 #define spin_trylock_irqsave(lock, flags) \
 220 ({ \
 221         local_irq_save(flags); \
 222         _spin_trylock(lock) ? \
 223         1 : ({ local_irq_restore(flags); 0; }); \
 224 })
 225
 226 /*
 227  * Pull the atomic_t declaration:
 228  * (asm-mips/atomic.h needs above definitions)
 229  */
 230 #include <asm/atomic.h>
 231 /**
 232  * atomic_dec_and_lock - lock on reaching reference count zero
 233  * @atomic: the atomic counter
 234  * @lock: the spinlock in question
 235  */
 236 extern int _atomic_dec_and_lock(atomic_t *atomic, spinlock_t *lock);
 237 #define atomic_dec_and_lock(atomic, lock) \
 238                 __cond_lock(_atomic_dec_and_lock(atomic, lock))
 239
 240 /**
 241  * spin_can_lock - would spin_trylock() succeed?
 242  * @lock: the spinlock in question.
 243  */
 244 #define spin_can_lock(lock)     (!spin_is_locked(lock))
 245
 246 #endif /* __LINUX_SPINLOCK_H */