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 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 #ifdef CONFIG_SMP
  88 # include <asm/spinlock.h>
  89 #else
  90 # include <linux/spinlock_up.h>
  91 #endif
  92
  93 #ifdef CONFIG_DEBUG_SPINLOCK
  94   extern void __spin_lock_init(spinlock_t *lock, const char *name,
  95                                struct lock_class_key *key);
  96 # define spin_lock_init(lock)                                   \
  97 do {                                                            \
  98         static struct lock_class_key __key;                     \
  99                                                                 \
 100         __spin_lock_init((lock), #lock, &__key);                \
 101 } while (0)
 102
 103 #else
 104 # define spin_lock_init(lock)                                   \
 105         do { *(lock) = SPIN_LOCK_UNLOCKED; } while (0)
 106 #endif
 107
 108 #ifdef CONFIG_DEBUG_SPINLOCK
 109   extern void __rwlock_init(rwlock_t *lock, const char *name,
 110                             struct lock_class_key *key);
 111 # define rwlock_init(lock)                                      \
 112 do {                                                            \
 113         static struct lock_class_key __key;                     \
 114                                                                 \
 115         __rwlock_init((lock), #lock, &__key);                   \
 116 } while (0)
 117 #else
 118 # define rwlock_init(lock)                                      \
 119         do { *(lock) = RW_LOCK_UNLOCKED; } while (0)
 120 #endif
 121
 122 #define spin_is_locked(lock)    __raw_spin_is_locked(&(lock)->raw_lock)
 123
 124 #ifdef CONFIG_GENERIC_LOCKBREAK
 125 #define spin_is_contended(lock) ((lock)->break_lock)
 126 #else
 127
 128 #ifdef __raw_spin_is_contended
 129 #define spin_is_contended(lock) __raw_spin_is_contended(&(lock)->raw_lock)
 130 #else
 131 #define spin_is_contended(lock) (((void)(lock), 0))
 132 #endif /*__raw_spin_is_contended*/
 133 #endif
 134
 135 /* The lock does not imply full memory barrier. */
 136 #ifndef ARCH_HAS_SMP_MB_AFTER_LOCK
 137 static inline void smp_mb__after_lock(void) { smp_mb(); }
 138 #endif
 139
 140 /**
 141  * spin_unlock_wait - wait until the spinlock gets unlocked
 142  * @lock: the spinlock in question.
 143  */
 144 #define spin_unlock_wait(lock)  __raw_spin_unlock_wait(&(lock)->raw_lock)
 145
 146 #ifdef CONFIG_DEBUG_SPINLOCK
 147  extern void _raw_spin_lock(spinlock_t *lock);
 148 #define _raw_spin_lock_flags(lock, flags) _raw_spin_lock(lock)
 149  extern int _raw_spin_trylock(spinlock_t *lock);
 150  extern void _raw_spin_unlock(spinlock_t *lock);
 151  extern void _raw_read_lock(rwlock_t *lock);
 152 #define _raw_read_lock_flags(lock, flags) _raw_read_lock(lock)
 153  extern int _raw_read_trylock(rwlock_t *lock);
 154  extern void _raw_read_unlock(rwlock_t *lock);
 155  extern void _raw_write_lock(rwlock_t *lock);
 156 #define _raw_write_lock_flags(lock, flags) _raw_write_lock(lock)
 157  extern int _raw_write_trylock(rwlock_t *lock);
 158  extern void _raw_write_unlock(rwlock_t *lock);
 159 #else
 160 # define _raw_spin_lock(lock)           __raw_spin_lock(&(lock)->raw_lock)
 161 # define _raw_spin_lock_flags(lock, flags) \
 162                 __raw_spin_lock_flags(&(lock)->raw_lock, *(flags))
 163 # define _raw_spin_trylock(lock)        __raw_spin_trylock(&(lock)->raw_lock)
 164 # define _raw_spin_unlock(lock)         __raw_spin_unlock(&(lock)->raw_lock)
 165 # define _raw_read_lock(rwlock)         __raw_read_lock(&(rwlock)->raw_lock)
 166 # define _raw_read_lock_flags(lock, flags) \
 167                 __raw_read_lock_flags(&(lock)->raw_lock, *(flags))
 168 # define _raw_read_trylock(rwlock)      __raw_read_trylock(&(rwlock)->raw_lock)
 169 # define _raw_read_unlock(rwlock)       __raw_read_unlock(&(rwlock)->raw_lock)
 170 # define _raw_write_lock(rwlock)        __raw_write_lock(&(rwlock)->raw_lock)
 171 # define _raw_write_lock_flags(lock, flags) \
 172                 __raw_write_lock_flags(&(lock)->raw_lock, *(flags))
 173 # define _raw_write_trylock(rwlock)     __raw_write_trylock(&(rwlock)->raw_lock)
 174 # define _raw_write_unlock(rwlock)      __raw_write_unlock(&(rwlock)->raw_lock)
 175 #endif
 176
 177 #define read_can_lock(rwlock)           __raw_read_can_lock(&(rwlock)->raw_lock)
 178 #define write_can_lock(rwlock)          __raw_write_can_lock(&(rwlock)->raw_lock)
 179
 180 /*
 181  * Define the various spin_lock and rw_lock methods.  Note we define these
 182  * regardless of whether CONFIG_SMP or CONFIG_PREEMPT are set. The various
 183  * methods are defined as nops in the case they are not required.
 184  */
 185 #define spin_trylock(lock)              __cond_lock(lock, _spin_trylock(lock))
 186 #define read_trylock(lock)              __cond_lock(lock, _read_trylock(lock))
 187 #define write_trylock(lock)             __cond_lock(lock, _write_trylock(lock))
 188
 189 #define spin_lock(lock)                 _spin_lock(lock)
 190
 191 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 192 # define spin_lock_nested(lock, subclass) _spin_lock_nested(lock, subclass)
 193 # define spin_lock_nest_lock(lock, nest_lock)                           \
 194          do {                                                           \
 195                  typecheck(struct lockdep_map *, &(nest_lock)->dep_map);\
 196                  _spin_lock_nest_lock(lock, &(nest_lock)->dep_map);     \
 197          } while (0)
 198 #else
 199 # define spin_lock_nested(lock, subclass) _spin_lock(lock)
 200 # define spin_lock_nest_lock(lock, nest_lock) _spin_lock(lock)
 201 #endif
 202
 203 #define write_lock(lock)                _write_lock(lock)
 204 #define read_lock(lock)                 _read_lock(lock)
 205
 206 #if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
 207
 208 #define spin_lock_irqsave(lock, flags)                  \
 209         do {                                            \
 210                 typecheck(unsigned long, flags);        \
 211                 flags = _spin_lock_irqsave(lock);       \
 212         } while (0)
 213 #define read_lock_irqsave(lock, flags)                  \
 214         do {                                            \
 215                 typecheck(unsigned long, flags);        \
 216                 flags = _read_lock_irqsave(lock);       \
 217         } while (0)
 218 #define write_lock_irqsave(lock, flags)                 \
 219         do {                                            \
 220                 typecheck(unsigned long, flags);        \
 221                 flags = _write_lock_irqsave(lock);      \
 222         } while (0)
 223
 224 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 225 #define spin_lock_irqsave_nested(lock, flags, subclass)                 \
 226         do {                                                            \
 227                 typecheck(unsigned long, flags);                        \
 228                 flags = _spin_lock_irqsave_nested(lock, subclass);      \
 229         } while (0)
 230 #else
 231 #define spin_lock_irqsave_nested(lock, flags, subclass)                 \
 232         do {                                                            \
 233                 typecheck(unsigned long, flags);                        \
 234                 flags = _spin_lock_irqsave(lock);                       \
 235         } while (0)
 236 #endif
 237
 238 #else
 239
 240 #define spin_lock_irqsave(lock, flags)                  \
 241         do {                                            \
 242                 typecheck(unsigned long, flags);        \
 243                 _spin_lock_irqsave(lock, flags);        \
 244         } while (0)
 245 #define read_lock_irqsave(lock, flags)                  \
 246         do {                                            \
 247                 typecheck(unsigned long, flags);        \
 248                 _read_lock_irqsave(lock, flags);        \
 249         } while (0)
 250 #define write_lock_irqsave(lock, flags)                 \
 251         do {                                            \
 252                 typecheck(unsigned long, flags);        \
 253                 _write_lock_irqsave(lock, flags);       \
 254         } while (0)
 255 #define spin_lock_irqsave_nested(lock, flags, subclass) \
 256         spin_lock_irqsave(lock, flags)
 257
 258 #endif
 259
 260 #define spin_lock_irq(lock)             _spin_lock_irq(lock)
 261 #define spin_lock_bh(lock)              _spin_lock_bh(lock)
 262 #define read_lock_irq(lock)             _read_lock_irq(lock)
 263 #define read_lock_bh(lock)              _read_lock_bh(lock)
 264 #define write_lock_irq(lock)            _write_lock_irq(lock)
 265 #define write_lock_bh(lock)             _write_lock_bh(lock)
 266 #define spin_unlock(lock)               _spin_unlock(lock)
 267 #define read_unlock(lock)               _read_unlock(lock)
 268 #define write_unlock(lock)              _write_unlock(lock)
 269 #define spin_unlock_irq(lock)           _spin_unlock_irq(lock)
 270 #define read_unlock_irq(lock)           _read_unlock_irq(lock)
 271 #define write_unlock_irq(lock)          _write_unlock_irq(lock)
 272
 273 #define spin_unlock_irqrestore(lock, flags)             \
 274         do {                                            \
 275                 typecheck(unsigned long, flags);        \
 276                 _spin_unlock_irqrestore(lock, flags);   \
 277         } while (0)
 278 #define spin_unlock_bh(lock)            _spin_unlock_bh(lock)
 279
 280 #define read_unlock_irqrestore(lock, flags)             \
 281         do {                                            \
 282                 typecheck(unsigned long, flags);        \
 283                 _read_unlock_irqrestore(lock, flags);   \
 284         } while (0)
 285 #define read_unlock_bh(lock)            _read_unlock_bh(lock)
 286
 287 #define write_unlock_irqrestore(lock, flags)            \
 288         do {                                            \
 289                 typecheck(unsigned long, flags);        \
 290                 _write_unlock_irqrestore(lock, flags);  \
 291         } while (0)
 292 #define write_unlock_bh(lock)           _write_unlock_bh(lock)
 293
 294 #define spin_trylock_bh(lock)   __cond_lock(lock, _spin_trylock_bh(lock))
 295
 296 #define spin_trylock_irq(lock) \
 297 ({ \
 298         local_irq_disable(); \
 299         spin_trylock(lock) ? \
 300         1 : ({ local_irq_enable(); 0;  }); \
 301 })
 302
 303 #define spin_trylock_irqsave(lock, flags) \
 304 ({ \
 305         local_irq_save(flags); \
 306         spin_trylock(lock) ? \
 307         1 : ({ local_irq_restore(flags); 0; }); \
 308 })
 309
 310 #define write_trylock_irqsave(lock, flags) \
 311 ({ \
 312         local_irq_save(flags); \
 313         write_trylock(lock) ? \
 314         1 : ({ local_irq_restore(flags); 0; }); \
 315 })
 316
 317 /*
 318  * Pull the atomic_t declaration:
 319  * (asm-mips/atomic.h needs above definitions)
 320  */
 321 #include <asm/atomic.h>
 322 /**
 323  * atomic_dec_and_lock - lock on reaching reference count zero
 324  * @atomic: the atomic counter
 325  * @lock: the spinlock in question
 326  *
 327  * Decrements @atomic by 1.  If the result is 0, returns true and locks
 328  * @lock.  Returns false for all other cases.
 329  */
 330 extern int _atomic_dec_and_lock(atomic_t *atomic, spinlock_t *lock);
 331 #define atomic_dec_and_lock(atomic, lock) \
 332                 __cond_lock(lock, _atomic_dec_and_lock(atomic, lock))
 333
 334 /**
 335  * spin_can_lock - would spin_trylock() succeed?
 336  * @lock: the spinlock in question.
 337  */
 338 #define spin_can_lock(lock)     (!spin_is_locked(lock))
 339
 340 /*
 341  * Pull the _spin_*()/_read_*()/_write_*() functions/declarations:
 342  */
 343 #if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
 344 # include <linux/spinlock_api_smp.h>
 345 #else
 346 # include <linux/spinlock_api_up.h>
 347 #endif
 348
 349 #endif /* __LINUX_SPINLOCK_H */