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