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/typecheck.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 #include <linux/bottom_half.h>
  57
  58 #include <asm/system.h>
  59
  60 /*
  61  * Must define these before including other files, inline functions need them
  62  */
  63 #define LOCK_SECTION_NAME ".text.lock."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 __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 /*
  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(lock); } 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(lock); } while (0)
 118 #endif
 119
 120 #define spin_is_locked(lock)    __raw_spin_is_locked(&(lock)->raw_lock)
 121
 122 #ifdef CONFIG_GENERIC_LOCKBREAK
 123 #define spin_is_contended(lock) ((lock)->break_lock)
 124 #else
 125
 126 #ifdef __raw_spin_is_contended
 127 #define spin_is_contended(lock) __raw_spin_is_contended(&(lock)->raw_lock)
 128 #else
 129 #define spin_is_contended(lock) (((void)(lock), 0))
 130 #endif /*__raw_spin_is_contended*/
 131 #endif
 132
 133 /* The lock does not imply full memory barrier. */
 134 #ifndef ARCH_HAS_SMP_MB_AFTER_LOCK
 135 static inline void smp_mb__after_lock(void) { smp_mb(); }
 136 #endif
 137
 138 /**
 139  * spin_unlock_wait - wait until the spinlock gets unlocked
 140  * @lock: the spinlock in question.
 141  */
 142 #define spin_unlock_wait(lock)  __raw_spin_unlock_wait(&(lock)->raw_lock)
 143
 144 #ifdef CONFIG_DEBUG_SPINLOCK
 145  extern void _raw_spin_lock(spinlock_t *lock);
 146 #define _raw_spin_lock_flags(lock, flags) _raw_spin_lock(lock)
 147  extern int _raw_spin_trylock(spinlock_t *lock);
 148  extern void _raw_spin_unlock(spinlock_t *lock);
 149  extern void _raw_read_lock(rwlock_t *lock);
 150 #define _raw_read_lock_flags(lock, flags) _raw_read_lock(lock)
 151  extern int _raw_read_trylock(rwlock_t *lock);
 152  extern void _raw_read_unlock(rwlock_t *lock);
 153  extern void _raw_write_lock(rwlock_t *lock);
 154 #define _raw_write_lock_flags(lock, flags) _raw_write_lock(lock)
 155  extern int _raw_write_trylock(rwlock_t *lock);
 156  extern void _raw_write_unlock(rwlock_t *lock);
 157 #else
 158 # define _raw_spin_lock(lock)           __raw_spin_lock(&(lock)->raw_lock)
 159 # define _raw_spin_lock_flags(lock, flags) \
 160                 __raw_spin_lock_flags(&(lock)->raw_lock, *(flags))
 161 # define _raw_spin_trylock(lock)        __raw_spin_trylock(&(lock)->raw_lock)
 162 # define _raw_spin_unlock(lock)         __raw_spin_unlock(&(lock)->raw_lock)
 163 # define _raw_read_lock(rwlock)         __raw_read_lock(&(rwlock)->raw_lock)
 164 # define _raw_read_lock_flags(lock, flags) \
 165                 __raw_read_lock_flags(&(lock)->raw_lock, *(flags))
 166 # define _raw_read_trylock(rwlock)      __raw_read_trylock(&(rwlock)->raw_lock)
 167 # define _raw_read_unlock(rwlock)       __raw_read_unlock(&(rwlock)->raw_lock)
 168 # define _raw_write_lock(rwlock)        __raw_write_lock(&(rwlock)->raw_lock)
 169 # define _raw_write_lock_flags(lock, flags) \
 170                 __raw_write_lock_flags(&(lock)->raw_lock, *(flags))
 171 # define _raw_write_trylock(rwlock)     __raw_write_trylock(&(rwlock)->raw_lock)
 172 # define _raw_write_unlock(rwlock)      __raw_write_unlock(&(rwlock)->raw_lock)
 173 #endif
 174
 175 #define read_can_lock(rwlock)           __raw_read_can_lock(&(rwlock)->raw_lock)
 176 #define write_can_lock(rwlock)          __raw_write_can_lock(&(rwlock)->raw_lock)
 177
 178 /*
 179  * Define the various spin_lock and rw_lock methods.  Note we define these
 180  * regardless of whether CONFIG_SMP or CONFIG_PREEMPT are set. The various
 181  * methods are defined as nops in the case they are not required.
 182  */
 183 #define spin_trylock(lock)              __cond_lock(lock, _spin_trylock(lock))
 184 #define read_trylock(lock)              __cond_lock(lock, _read_trylock(lock))
 185 #define write_trylock(lock)             __cond_lock(lock, _write_trylock(lock))
 186
 187 #define spin_lock(lock)                 _spin_lock(lock)
 188
 189 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 190 # define spin_lock_nested(lock, subclass) _spin_lock_nested(lock, subclass)
 191 # define spin_lock_nest_lock(lock, nest_lock)                           \
 192          do {                                                           \
 193                  typecheck(struct lockdep_map *, &(nest_lock)->dep_map);\
 194                  _spin_lock_nest_lock(lock, &(nest_lock)->dep_map);     \
 195          } while (0)
 196 #else
 197 # define spin_lock_nested(lock, subclass) _spin_lock(lock)
 198 # define spin_lock_nest_lock(lock, nest_lock) _spin_lock(lock)
 199 #endif
 200
 201 #define write_lock(lock)                _write_lock(lock)
 202 #define read_lock(lock)                 _read_lock(lock)
 203
 204 #if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
 205
 206 #define spin_lock_irqsave(lock, flags)                  \
 207         do {                                            \
 208                 typecheck(unsigned long, flags);        \
 209                 flags = _spin_lock_irqsave(lock);       \
 210         } while (0)
 211 #define read_lock_irqsave(lock, flags)                  \
 212         do {                                            \
 213                 typecheck(unsigned long, flags);        \
 214                 flags = _read_lock_irqsave(lock);       \
 215         } while (0)
 216 #define write_lock_irqsave(lock, flags)                 \
 217         do {                                            \
 218                 typecheck(unsigned long, flags);        \
 219                 flags = _write_lock_irqsave(lock);      \
 220         } while (0)
 221
 222 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 223 #define spin_lock_irqsave_nested(lock, flags, subclass)                 \
 224         do {                                                            \
 225                 typecheck(unsigned long, flags);                        \
 226                 flags = _spin_lock_irqsave_nested(lock, subclass);      \
 227         } while (0)
 228 #else
 229 #define spin_lock_irqsave_nested(lock, flags, subclass)                 \
 230         do {                                                            \
 231                 typecheck(unsigned long, flags);                        \
 232                 flags = _spin_lock_irqsave(lock);                       \
 233         } while (0)
 234 #endif
 235
 236 #else
 237
 238 #define spin_lock_irqsave(lock, flags)                  \
 239         do {                                            \
 240                 typecheck(unsigned long, flags);        \
 241                 _spin_lock_irqsave(lock, flags);        \
 242         } while (0)
 243 #define read_lock_irqsave(lock, flags)                  \
 244         do {                                            \
 245                 typecheck(unsigned long, flags);        \
 246                 _read_lock_irqsave(lock, flags);        \
 247         } while (0)
 248 #define write_lock_irqsave(lock, flags)                 \
 249         do {                                            \
 250                 typecheck(unsigned long, flags);        \
 251                 _write_lock_irqsave(lock, flags);       \
 252         } while (0)
 253 #define spin_lock_irqsave_nested(lock, flags, subclass) \
 254         spin_lock_irqsave(lock, flags)
 255
 256 #endif
 257
 258 #define spin_lock_irq(lock)             _spin_lock_irq(lock)
 259 #define spin_lock_bh(lock)              _spin_lock_bh(lock)
 260 #define read_lock_irq(lock)             _read_lock_irq(lock)
 261 #define read_lock_bh(lock)              _read_lock_bh(lock)
 262 #define write_lock_irq(lock)            _write_lock_irq(lock)
 263 #define write_lock_bh(lock)             _write_lock_bh(lock)
 264 #define spin_unlock(lock)               _spin_unlock(lock)
 265 #define read_unlock(lock)               _read_unlock(lock)
 266 #define write_unlock(lock)              _write_unlock(lock)
 267 #define spin_unlock_irq(lock)           _spin_unlock_irq(lock)
 268 #define read_unlock_irq(lock)           _read_unlock_irq(lock)
 269 #define write_unlock_irq(lock)          _write_unlock_irq(lock)
 270
 271 #define spin_unlock_irqrestore(lock, flags)             \
 272         do {                                            \
 273                 typecheck(unsigned long, flags);        \
 274                 _spin_unlock_irqrestore(lock, flags);   \
 275         } while (0)
 276 #define spin_unlock_bh(lock)            _spin_unlock_bh(lock)
 277
 278 #define read_unlock_irqrestore(lock, flags)             \
 279         do {                                            \
 280                 typecheck(unsigned long, flags);        \
 281                 _read_unlock_irqrestore(lock, flags);   \
 282         } while (0)
 283 #define read_unlock_bh(lock)            _read_unlock_bh(lock)
 284
 285 #define write_unlock_irqrestore(lock, flags)            \
 286         do {                                            \
 287                 typecheck(unsigned long, flags);        \
 288                 _write_unlock_irqrestore(lock, flags);  \
 289         } while (0)
 290 #define write_unlock_bh(lock)           _write_unlock_bh(lock)
 291
 292 #define spin_trylock_bh(lock)   __cond_lock(lock, _spin_trylock_bh(lock))
 293
 294 #define spin_trylock_irq(lock) \
 295 ({ \
 296         local_irq_disable(); \
 297         spin_trylock(lock) ? \
 298         1 : ({ local_irq_enable(); 0;  }); \
 299 })
 300
 301 #define spin_trylock_irqsave(lock, flags) \
 302 ({ \
 303         local_irq_save(flags); \
 304         spin_trylock(lock) ? \
 305         1 : ({ local_irq_restore(flags); 0; }); \
 306 })
 307
 308 #define write_trylock_irqsave(lock, flags) \
 309 ({ \
 310         local_irq_save(flags); \
 311         write_trylock(lock) ? \
 312         1 : ({ local_irq_restore(flags); 0; }); \
 313 })
 314
 315 /*
 316  * Pull the atomic_t declaration:
 317  * (asm-mips/atomic.h needs above definitions)
 318  */
 319 #include <asm/atomic.h>
 320 /**
 321  * atomic_dec_and_lock - lock on reaching reference count zero
 322  * @atomic: the atomic counter
 323  * @lock: the spinlock in question
 324  *
 325  * Decrements @atomic by 1.  If the result is 0, returns true and locks
 326  * @lock.  Returns false for all other cases.
 327  */
 328 extern int _atomic_dec_and_lock(atomic_t *atomic, spinlock_t *lock);
 329 #define atomic_dec_and_lock(atomic, lock) \
 330                 __cond_lock(lock, _atomic_dec_and_lock(atomic, lock))
 331
 332 /**
 333  * spin_can_lock - would spin_trylock() succeed?
 334  * @lock: the spinlock in question.
 335  */
 336 #define spin_can_lock(lock)     (!spin_is_locked(lock))
 337
 338 /*
 339  * Pull the _spin_*()/_read_*()/_write_*() functions/declarations:
 340  */
 341 #if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
 342 # include <linux/spinlock_api_smp.h>
 343 #else
 344 # include <linux/spinlock_api_up.h>
 345 #endif
 346
 347 #endif /* __LINUX_SPINLOCK_H */