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/config.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
  57 #include <asm/system.h>
  58
  59 /*
  60  * Must define these before including other files, inline functions need them
  61  */
  62 #define LOCK_SECTION_NAME ".text.lock."KBUILD_BASENAME
  63
  64 #define LOCK_SECTION_START(extra)               \
  65         ".subsection 1\n\t"                     \
  66         extra                                   \
  67         ".ifndef " LOCK_SECTION_NAME "\n\t"     \
  68         LOCK_SECTION_NAME ":\n\t"               \
  69         ".endif\n"
  70
  71 #define LOCK_SECTION_END                        \
  72         ".previous\n\t"
  73
  74 #define __lockfunc fastcall __attribute__((section(".spinlock.text")))
  75
  76 /*
  77  * Pull the raw_spinlock_t and raw_rwlock_t definitions:
  78  */
  79 #include <linux/spinlock_types.h>
  80
  81 extern int __lockfunc generic__raw_read_trylock(raw_rwlock_t *lock);
  82
  83 /*
  84  * Pull the __raw*() functions/declarations (UP-nondebug doesnt need them):
  85  */
  86 #if defined(CONFIG_SMP)
  87 # include <asm/spinlock.h>
  88 #else
  89 # include <linux/spinlock_up.h>
  90 #endif
  91
  92 #define spin_lock_init(lock)    do { *(lock) = SPIN_LOCK_UNLOCKED; } while (0)
  93 #define rwlock_init(lock)       do { *(lock) = RW_LOCK_UNLOCKED; } while (0)
  94
  95 #define spin_is_locked(lock)    __raw_spin_is_locked(&(lock)->raw_lock)
  96
  97 /**
  98  * spin_unlock_wait - wait until the spinlock gets unlocked
  99  * @lock: the spinlock in question.
 100  */
 101 #define spin_unlock_wait(lock)  __raw_spin_unlock_wait(&(lock)->raw_lock)
 102
 103 /*
 104  * Pull the _spin_*()/_read_*()/_write_*() functions/declarations:
 105  */
 106 #if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
 107 # include <linux/spinlock_api_smp.h>
 108 #else
 109 # include <linux/spinlock_api_up.h>
 110 #endif
 111
 112 #ifdef CONFIG_DEBUG_SPINLOCK
 113  extern void _raw_spin_lock(spinlock_t *lock);
 114 #define _raw_spin_lock_flags(lock, flags) _raw_spin_lock(lock)
 115  extern int _raw_spin_trylock(spinlock_t *lock);
 116  extern void _raw_spin_unlock(spinlock_t *lock);
 117
 118  extern void _raw_read_lock(rwlock_t *lock);
 119  extern int _raw_read_trylock(rwlock_t *lock);
 120  extern void _raw_read_unlock(rwlock_t *lock);
 121  extern void _raw_write_lock(rwlock_t *lock);
 122  extern int _raw_write_trylock(rwlock_t *lock);
 123  extern void _raw_write_unlock(rwlock_t *lock);
 124 #else
 125 # define _raw_spin_unlock(lock)         __raw_spin_unlock(&(lock)->raw_lock)
 126 # define _raw_spin_trylock(lock)        __raw_spin_trylock(&(lock)->raw_lock)
 127 # define _raw_spin_lock(lock)           __raw_spin_lock(&(lock)->raw_lock)
 128 # define _raw_spin_lock_flags(lock, flags) \
 129                 __raw_spin_lock_flags(&(lock)->raw_lock, *(flags))
 130 # define _raw_read_lock(rwlock)         __raw_read_lock(&(rwlock)->raw_lock)
 131 # define _raw_write_lock(rwlock)        __raw_write_lock(&(rwlock)->raw_lock)
 132 # define _raw_read_unlock(rwlock)       __raw_read_unlock(&(rwlock)->raw_lock)
 133 # define _raw_write_unlock(rwlock)      __raw_write_unlock(&(rwlock)->raw_lock)
 134 # define _raw_read_trylock(rwlock)      __raw_read_trylock(&(rwlock)->raw_lock)
 135 # define _raw_write_trylock(rwlock)     __raw_write_trylock(&(rwlock)->raw_lock)
 136 #endif
 137
 138 #define read_can_lock(rwlock)           __raw_read_can_lock(&(rwlock)->raw_lock)
 139 #define write_can_lock(rwlock)          __raw_write_can_lock(&(rwlock)->raw_lock)
 140
 141 /*
 142  * Define the various spin_lock and rw_lock methods.  Note we define these
 143  * regardless of whether CONFIG_SMP or CONFIG_PREEMPT are set. The various
 144  * methods are defined as nops in the case they are not required.
 145  */
 146 #define spin_trylock(lock)              __cond_lock(_spin_trylock(lock))
 147 #define read_trylock(lock)              __cond_lock(_read_trylock(lock))
 148 #define write_trylock(lock)             __cond_lock(_write_trylock(lock))
 149
 150 #define spin_lock(lock)                 _spin_lock(lock)
 151 #define write_lock(lock)                _write_lock(lock)
 152 #define read_lock(lock)                 _read_lock(lock)
 153
 154 #if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
 155 #define spin_lock_irqsave(lock, flags)  flags = _spin_lock_irqsave(lock)
 156 #define read_lock_irqsave(lock, flags)  flags = _read_lock_irqsave(lock)
 157 #define write_lock_irqsave(lock, flags) flags = _write_lock_irqsave(lock)
 158 #else
 159 #define spin_lock_irqsave(lock, flags)  _spin_lock_irqsave(lock, flags)
 160 #define read_lock_irqsave(lock, flags)  _read_lock_irqsave(lock, flags)
 161 #define write_lock_irqsave(lock, flags) _write_lock_irqsave(lock, flags)
 162 #endif
 163
 164 #define spin_lock_irq(lock)             _spin_lock_irq(lock)
 165 #define spin_lock_bh(lock)              _spin_lock_bh(lock)
 166
 167 #define read_lock_irq(lock)             _read_lock_irq(lock)
 168 #define read_lock_bh(lock)              _read_lock_bh(lock)
 169
 170 #define write_lock_irq(lock)            _write_lock_irq(lock)
 171 #define write_lock_bh(lock)             _write_lock_bh(lock)
 172
 173 /*
 174  * We inline the unlock functions in the nondebug case:
 175  */
 176 #if defined(CONFIG_DEBUG_SPINLOCK) || defined(CONFIG_PREEMPT) || !defined(CONFIG_SMP)
 177 # define spin_unlock(lock)              _spin_unlock(lock)
 178 # define read_unlock(lock)              _read_unlock(lock)
 179 # define write_unlock(lock)             _write_unlock(lock)
 180 #else
 181 # define spin_unlock(lock)              __raw_spin_unlock(&(lock)->raw_lock)
 182 # define read_unlock(lock)              __raw_read_unlock(&(lock)->raw_lock)
 183 # define write_unlock(lock)             __raw_write_unlock(&(lock)->raw_lock)
 184 #endif
 185
 186 #if defined(CONFIG_DEBUG_SPINLOCK) || defined(CONFIG_PREEMPT) || !defined(CONFIG_SMP)
 187 # define spin_unlock_irq(lock)          _spin_unlock_irq(lock)
 188 # define read_unlock_irq(lock)          _read_unlock_irq(lock)
 189 # define write_unlock_irq(lock)         _write_unlock_irq(lock)
 190 #else
 191 # define spin_unlock_irq(lock) \
 192     do { __raw_spin_unlock(&(lock)->raw_lock); local_irq_enable(); } while (0)
 193 # define read_unlock_irq(lock) \
 194     do { __raw_read_unlock(&(lock)->raw_lock); local_irq_enable(); } while (0)
 195 # define write_unlock_irq(lock) \
 196     do { __raw_write_unlock(&(lock)->raw_lock); local_irq_enable(); } while (0)
 197 #endif
 198
 199 #define spin_unlock_irqrestore(lock, flags) \
 200                                         _spin_unlock_irqrestore(lock, flags)
 201 #define spin_unlock_bh(lock)            _spin_unlock_bh(lock)
 202
 203 #define read_unlock_irqrestore(lock, flags) \
 204                                         _read_unlock_irqrestore(lock, flags)
 205 #define read_unlock_bh(lock)            _read_unlock_bh(lock)
 206
 207 #define write_unlock_irqrestore(lock, flags) \
 208                                         _write_unlock_irqrestore(lock, flags)
 209 #define write_unlock_bh(lock)           _write_unlock_bh(lock)
 210
 211 #define spin_trylock_bh(lock)           __cond_lock(_spin_trylock_bh(lock))
 212
 213 #define spin_trylock_irq(lock) \
 214 ({ \
 215         local_irq_disable(); \
 216         _spin_trylock(lock) ? \
 217         1 : ({ local_irq_enable(); 0;  }); \
 218 })
 219
 220 #define spin_trylock_irqsave(lock, flags) \
 221 ({ \
 222         local_irq_save(flags); \
 223         _spin_trylock(lock) ? \
 224         1 : ({ local_irq_restore(flags); 0; }); \
 225 })
 226
 227 /*
 228  * Pull the atomic_t declaration:
 229  * (asm-mips/atomic.h needs above definitions)
 230  */
 231 #include <asm/atomic.h>
 232 /**
 233  * atomic_dec_and_lock - lock on reaching reference count zero
 234  * @atomic: the atomic counter
 235  * @lock: the spinlock in question
 236  */
 237 extern int _atomic_dec_and_lock(atomic_t *atomic, spinlock_t *lock);
 238 #define atomic_dec_and_lock(atomic, lock) \
 239                 __cond_lock(_atomic_dec_and_lock(atomic, lock))
 240
 241 /**
 242  * spin_can_lock - would spin_trylock() succeed?
 243  * @lock: the spinlock in question.
 244  */
 245 #define spin_can_lock(lock)     (!spin_is_locked(lock))
 246
 247 #endif /* __LINUX_SPINLOCK_H */