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   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 arch_spinlock_t/arch_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 arch_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 arch_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 arch_spinlock_t and arch_rwlock_t definitions:
  79  */
  80 #include <linux/spinlock_types.h>
  81
  82 /*
  83  * Pull the arch_spin*() 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 __raw_spin_lock_init(raw_spinlock_t *lock, const char *name,
  93                                    struct lock_class_key *key);
  94 # define raw_spin_lock_init(lock)                               \
  95 do {                                                            \
  96         static struct lock_class_key __key;                     \
  97                                                                 \
  98         __raw_spin_lock_init((lock), #lock, &__key);            \
  99 } while (0)
 100
 101 #else
 102 # define raw_spin_lock_init(lock)                               \
 103         do { *(lock) = __RAW_SPIN_LOCK_UNLOCKED(lock); } while (0)
 104 #endif
 105
 106 #define raw_spin_is_locked(lock)        arch_spin_is_locked(&(lock)->raw_lock)
 107
 108 #ifdef CONFIG_GENERIC_LOCKBREAK
 109 #define raw_spin_is_contended(lock) ((lock)->break_lock)
 110 #else
 111
 112 #ifdef arch_spin_is_contended
 113 #define raw_spin_is_contended(lock)     arch_spin_is_contended(&(lock)->raw_lock)
 114 #else
 115 #define raw_spin_is_contended(lock)     (((void)(lock), 0))
 116 #endif /*arch_spin_is_contended*/
 117 #endif
 118
 119 /* The lock does not imply full memory barrier. */
 120 #ifndef ARCH_HAS_SMP_MB_AFTER_LOCK
 121 static inline void smp_mb__after_lock(void) { smp_mb(); }
 122 #endif
 123
 124 /**
 125  * raw_spin_unlock_wait - wait until the spinlock gets unlocked
 126  * @lock: the spinlock in question.
 127  */
 128 #define raw_spin_unlock_wait(lock)      arch_spin_unlock_wait(&(lock)->raw_lock)
 129
 130 #ifdef CONFIG_DEBUG_SPINLOCK
 131  extern void do_raw_spin_lock(raw_spinlock_t *lock);
 132 #define do_raw_spin_lock_flags(lock, flags) do_raw_spin_lock(lock)
 133  extern int do_raw_spin_trylock(raw_spinlock_t *lock);
 134  extern void do_raw_spin_unlock(raw_spinlock_t *lock);
 135 #else
 136 static inline void do_raw_spin_lock(raw_spinlock_t *lock)
 137 {
 138         arch_spin_lock(&lock->raw_lock);
 139 }
 140
 141 static inline void
 142 do_raw_spin_lock_flags(raw_spinlock_t *lock, unsigned long *flags)
 143 {
 144         arch_spin_lock_flags(&lock->raw_lock, *flags);
 145 }
 146
 147 static inline int do_raw_spin_trylock(raw_spinlock_t *lock)
 148 {
 149         return arch_spin_trylock(&(lock)->raw_lock);
 150 }
 151
 152 static inline void do_raw_spin_unlock(raw_spinlock_t *lock)
 153 {
 154         arch_spin_unlock(&lock->raw_lock);
 155 }
 156 #endif
 157
 158 /*
 159  * Define the various spin_lock methods.  Note we define these
 160  * regardless of whether CONFIG_SMP or CONFIG_PREEMPT are set. The
 161  * various methods are defined as nops in the case they are not
 162  * required.
 163  */
 164 #define raw_spin_trylock(lock)          __cond_lock(lock, _spin_trylock(lock))
 165
 166 #define raw_spin_lock(lock)             _spin_lock(lock)
 167
 168 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 169 # define raw_spin_lock_nested(lock, subclass) _spin_lock_nested(lock, subclass)
 170 # define raw_spin_lock_nest_lock(lock, nest_lock)                       \
 171          do {                                                           \
 172                  typecheck(struct lockdep_map *, &(nest_lock)->dep_map);\
 173                  _spin_lock_nest_lock(lock, &(nest_lock)->dep_map);     \
 174          } while (0)
 175 #else
 176 # define raw_spin_lock_nested(lock, subclass)           _spin_lock(lock)
 177 # define raw_spin_lock_nest_lock(lock, nest_lock)       _spin_lock(lock)
 178 #endif
 179
 180 #if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
 181
 182 #define raw_spin_lock_irqsave(lock, flags)                      \
 183         do {                                            \
 184                 typecheck(unsigned long, flags);        \
 185                 flags = _spin_lock_irqsave(lock);       \
 186         } while (0)
 187
 188 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 189 #define raw_spin_lock_irqsave_nested(lock, flags, subclass)             \
 190         do {                                                            \
 191                 typecheck(unsigned long, flags);                        \
 192                 flags = _spin_lock_irqsave_nested(lock, subclass);      \
 193         } while (0)
 194 #else
 195 #define raw_spin_lock_irqsave_nested(lock, flags, subclass)             \
 196         do {                                                            \
 197                 typecheck(unsigned long, flags);                        \
 198                 flags = _spin_lock_irqsave(lock);                       \
 199         } while (0)
 200 #endif
 201
 202 #else
 203
 204 #define raw_spin_lock_irqsave(lock, flags)              \
 205         do {                                            \
 206                 typecheck(unsigned long, flags);        \
 207                 _spin_lock_irqsave(lock, flags);        \
 208         } while (0)
 209
 210 #define raw_spin_lock_irqsave_nested(lock, flags, subclass)     \
 211         raw_spin_lock_irqsave(lock, flags)
 212
 213 #endif
 214
 215 #define raw_spin_lock_irq(lock) _spin_lock_irq(lock)
 216 #define raw_spin_lock_bh(lock)          _spin_lock_bh(lock)
 217 #define raw_spin_unlock(lock)           _spin_unlock(lock)
 218 #define raw_spin_unlock_irq(lock)       _spin_unlock_irq(lock)
 219
 220 #define raw_spin_unlock_irqrestore(lock, flags)         \
 221         do {                                                    \
 222                 typecheck(unsigned long, flags);                \
 223                 _spin_unlock_irqrestore(lock, flags);   \
 224         } while (0)
 225 #define raw_spin_unlock_bh(lock)        _spin_unlock_bh(lock)
 226
 227 #define raw_spin_trylock_bh(lock)       __cond_lock(lock, _spin_trylock_bh(lock))
 228
 229 #define raw_spin_trylock_irq(lock) \
 230 ({ \
 231         local_irq_disable(); \
 232         raw_spin_trylock(lock) ? \
 233         1 : ({ local_irq_enable(); 0;  }); \
 234 })
 235
 236 #define raw_spin_trylock_irqsave(lock, flags) \
 237 ({ \
 238         local_irq_save(flags); \
 239         raw_spin_trylock(lock) ? \
 240         1 : ({ local_irq_restore(flags); 0; }); \
 241 })
 242
 243 /**
 244  * raw_spin_can_lock - would raw_spin_trylock() succeed?
 245  * @lock: the spinlock in question.
 246  */
 247 #define raw_spin_can_lock(lock) (!raw_spin_is_locked(lock))
 248
 249 /* Include rwlock functions */
 250 #include <linux/rwlock.h>
 251
 252 /*
 253  * Pull the _spin_*()/_read_*()/_write_*() functions/declarations:
 254  */
 255 #if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
 256 # include <linux/spinlock_api_smp.h>
 257 #else
 258 # include <linux/spinlock_api_up.h>
 259 #endif
 260
 261 /*
 262  * Map the spin_lock functions to the raw variants for PREEMPT_RT=n
 263  */
 264
 265 static inline raw_spinlock_t *spinlock_check(spinlock_t *lock)
 266 {
 267         return &lock->rlock;
 268 }
 269
 270 #define spin_lock_init(_lock)                           \
 271 do {                                                    \
 272         spinlock_check(_lock);                          \
 273         raw_spin_lock_init(&(_lock)->rlock);            \
 274 } while (0)
 275
 276 static inline void spin_lock(spinlock_t *lock)
 277 {
 278         raw_spin_lock(&lock->rlock);
 279 }
 280
 281 static inline void spin_lock_bh(spinlock_t *lock)
 282 {
 283         raw_spin_lock_bh(&lock->rlock);
 284 }
 285
 286 static inline int spin_trylock(spinlock_t *lock)
 287 {
 288         return raw_spin_trylock(&lock->rlock);
 289 }
 290
 291 #define spin_lock_nested(lock, subclass)                        \
 292 do {                                                            \
 293         raw_spin_lock_nested(spinlock_check(lock), subclass);   \
 294 } while (0)
 295
 296 #define spin_lock_nest_lock(lock, nest_lock)                            \
 297 do {                                                                    \
 298         raw_spin_lock_nest_lock(spinlock_check(lock), nest_lock);       \
 299 } while (0)
 300
 301 static inline void spin_lock_irq(spinlock_t *lock)
 302 {
 303         raw_spin_lock_irq(&lock->rlock);
 304 }
 305
 306 #define spin_lock_irqsave(lock, flags)                          \
 307 do {                                                            \
 308         raw_spin_lock_irqsave(spinlock_check(lock), flags);     \
 309 } while (0)
 310
 311 #define spin_lock_irqsave_nested(lock, flags, subclass)                 \
 312 do {                                                                    \
 313         raw_spin_lock_irqsave_nested(spinlock_check(lock), flags, subclass); \
 314 } while (0)
 315
 316 static inline void spin_unlock(spinlock_t *lock)
 317 {
 318         raw_spin_unlock(&lock->rlock);
 319 }
 320
 321 static inline void spin_unlock_bh(spinlock_t *lock)
 322 {
 323         raw_spin_unlock_bh(&lock->rlock);
 324 }
 325
 326 static inline void spin_unlock_irq(spinlock_t *lock)
 327 {
 328         raw_spin_unlock_irq(&lock->rlock);
 329 }
 330
 331 static inline void spin_unlock_irqrestore(spinlock_t *lock, unsigned long flags)
 332 {
 333         raw_spin_unlock_irqrestore(&lock->rlock, flags);
 334 }
 335
 336 static inline int spin_trylock_bh(spinlock_t *lock)
 337 {
 338         return raw_spin_trylock_bh(&lock->rlock);
 339 }
 340
 341 static inline int spin_trylock_irq(spinlock_t *lock)
 342 {
 343         return raw_spin_trylock_irq(&lock->rlock);
 344 }
 345
 346 #define spin_trylock_irqsave(lock, flags)                       \
 347 ({                                                              \
 348         raw_spin_trylock_irqsave(spinlock_check(lock), flags); \
 349 })
 350
 351 static inline void spin_unlock_wait(spinlock_t *lock)
 352 {
 353         raw_spin_unlock_wait(&lock->rlock);
 354 }
 355
 356 static inline int spin_is_locked(spinlock_t *lock)
 357 {
 358         return raw_spin_is_locked(&lock->rlock);
 359 }
 360
 361 static inline int spin_is_contended(spinlock_t *lock)
 362 {
 363         return raw_spin_is_contended(&lock->rlock);
 364 }
 365
 366 static inline int spin_can_lock(spinlock_t *lock)
 367 {
 368         return raw_spin_can_lock(&lock->rlock);
 369 }
 370
 371 static inline void assert_spin_locked(spinlock_t *lock)
 372 {
 373         assert_raw_spin_locked(&lock->rlock);
 374 }
 375
 376 /*
 377  * Pull the atomic_t declaration:
 378  * (asm-mips/atomic.h needs above definitions)
 379  */
 380 #include <asm/atomic.h>
 381 /**
 382  * atomic_dec_and_lock - lock on reaching reference count zero
 383  * @atomic: the atomic counter
 384  * @lock: the spinlock in question
 385  *
 386  * Decrements @atomic by 1.  If the result is 0, returns true and locks
 387  * @lock.  Returns false for all other cases.
 388  */
 389 extern int _atomic_dec_and_lock(atomic_t *atomic, spinlock_t *lock);
 390 #define atomic_dec_and_lock(atomic, lock) \
 391                 __cond_lock(lock, _atomic_dec_and_lock(atomic, lock))
 392
 393 #endif /* __LINUX_SPINLOCK_H */