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 #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)                                   \
  95 do {                                                            \
  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)                                      \
 110 do {                                                            \
 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(lock, _spin_trylock(lock))
 171 #define read_trylock(lock)              __cond_lock(lock, _read_trylock(lock))
 172 #define write_trylock(lock)             __cond_lock(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
 187 #define spin_lock_irqsave(lock, flags)  flags = _spin_lock_irqsave(lock)
 188 #define read_lock_irqsave(lock, flags)  flags = _read_lock_irqsave(lock)
 189 #define write_lock_irqsave(lock, flags) flags = _write_lock_irqsave(lock)
 190
 191 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 192 #define spin_lock_irqsave_nested(lock, flags, subclass) \
 193         flags = _spin_lock_irqsave_nested(lock, subclass)
 194 #else
 195 #define spin_lock_irqsave_nested(lock, flags, subclass) \
 196         flags = _spin_lock_irqsave(lock)
 197 #endif
 198
 199 #else
 200
 201 #define spin_lock_irqsave(lock, flags)  _spin_lock_irqsave(lock, flags)
 202 #define read_lock_irqsave(lock, flags)  _read_lock_irqsave(lock, flags)
 203 #define write_lock_irqsave(lock, flags) _write_lock_irqsave(lock, flags)
 204 #define spin_lock_irqsave_nested(lock, flags, subclass) \
 205         spin_lock_irqsave(lock, flags)
 206
 207 #endif
 208
 209 #define spin_lock_irq(lock)             _spin_lock_irq(lock)
 210 #define spin_lock_bh(lock)              _spin_lock_bh(lock)
 211
 212 #define read_lock_irq(lock)             _read_lock_irq(lock)
 213 #define read_lock_bh(lock)              _read_lock_bh(lock)
 214
 215 #define write_lock_irq(lock)            _write_lock_irq(lock)
 216 #define write_lock_bh(lock)             _write_lock_bh(lock)
 217
 218 /*
 219  * We inline the unlock functions in the nondebug case:
 220  */
 221 #if defined(CONFIG_DEBUG_SPINLOCK) || defined(CONFIG_PREEMPT) || \
 222         !defined(CONFIG_SMP)
 223 # define spin_unlock(lock)              _spin_unlock(lock)
 224 # define read_unlock(lock)              _read_unlock(lock)
 225 # define write_unlock(lock)             _write_unlock(lock)
 226 # define spin_unlock_irq(lock)          _spin_unlock_irq(lock)
 227 # define read_unlock_irq(lock)          _read_unlock_irq(lock)
 228 # define write_unlock_irq(lock)         _write_unlock_irq(lock)
 229 #else
 230 # define spin_unlock(lock)              __raw_spin_unlock(&(lock)->raw_lock)
 231 # define read_unlock(lock)              __raw_read_unlock(&(lock)->raw_lock)
 232 # define write_unlock(lock)             __raw_write_unlock(&(lock)->raw_lock)
 233 # define spin_unlock_irq(lock) \
 234     do { __raw_spin_unlock(&(lock)->raw_lock); local_irq_enable(); } while (0)
 235 # define read_unlock_irq(lock) \
 236     do { __raw_read_unlock(&(lock)->raw_lock); local_irq_enable(); } while (0)
 237 # define write_unlock_irq(lock) \
 238     do { __raw_write_unlock(&(lock)->raw_lock); local_irq_enable(); } while (0)
 239 #endif
 240
 241 #define spin_unlock_irqrestore(lock, flags) \
 242                                         _spin_unlock_irqrestore(lock, flags)
 243 #define spin_unlock_bh(lock)            _spin_unlock_bh(lock)
 244
 245 #define read_unlock_irqrestore(lock, flags) \
 246                                         _read_unlock_irqrestore(lock, flags)
 247 #define read_unlock_bh(lock)            _read_unlock_bh(lock)
 248
 249 #define write_unlock_irqrestore(lock, flags) \
 250                                         _write_unlock_irqrestore(lock, flags)
 251 #define write_unlock_bh(lock)           _write_unlock_bh(lock)
 252
 253 #define spin_trylock_bh(lock)   __cond_lock(lock, _spin_trylock_bh(lock))
 254
 255 #define spin_trylock_irq(lock) \
 256 ({ \
 257         local_irq_disable(); \
 258         spin_trylock(lock) ? \
 259         1 : ({ local_irq_enable(); 0;  }); \
 260 })
 261
 262 #define spin_trylock_irqsave(lock, flags) \
 263 ({ \
 264         local_irq_save(flags); \
 265         spin_trylock(lock) ? \
 266         1 : ({ local_irq_restore(flags); 0; }); \
 267 })
 268
 269 /*
 270  * Pull the atomic_t declaration:
 271  * (asm-mips/atomic.h needs above definitions)
 272  */
 273 #include <asm/atomic.h>
 274 /**
 275  * atomic_dec_and_lock - lock on reaching reference count zero
 276  * @atomic: the atomic counter
 277  * @lock: the spinlock in question
 278  */
 279 extern int _atomic_dec_and_lock(atomic_t *atomic, spinlock_t *lock);
 280 #define atomic_dec_and_lock(atomic, lock) \
 281                 __cond_lock(lock, _atomic_dec_and_lock(atomic, lock))
 282
 283 /**
 284  * spin_can_lock - would spin_trylock() succeed?
 285  * @lock: the spinlock in question.
 286  */
 287 #define spin_can_lock(lock)     (!spin_is_locked(lock))
 288
 289 #endif /* __LINUX_SPINLOCK_H */