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