spinlock.h 10 KB

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  1. #ifndef __LINUX_SPINLOCK_H
  2. #define __LINUX_SPINLOCK_H
  3. /*
  4. * include/linux/spinlock.h - generic spinlock/rwlock declarations
  5. *
  6. * here's the role of the various spinlock/rwlock related include files:
  7. *
  8. * on SMP builds:
  9. *
  10. * asm/spinlock_types.h: contains the arch_spinlock_t/arch_rwlock_t and the
  11. * initializers
  12. *
  13. * linux/spinlock_types.h:
  14. * defines the generic type and initializers
  15. *
  16. * asm/spinlock.h: contains the arch_spin_*()/etc. lowlevel
  17. * implementations, mostly inline assembly code
  18. *
  19. * (also included on UP-debug builds:)
  20. *
  21. * linux/spinlock_api_smp.h:
  22. * contains the prototypes for the _spin_*() APIs.
  23. *
  24. * linux/spinlock.h: builds the final spin_*() APIs.
  25. *
  26. * on UP builds:
  27. *
  28. * linux/spinlock_type_up.h:
  29. * contains the generic, simplified UP spinlock type.
  30. * (which is an empty structure on non-debug builds)
  31. *
  32. * linux/spinlock_types.h:
  33. * defines the generic type and initializers
  34. *
  35. * linux/spinlock_up.h:
  36. * contains the arch_spin_*()/etc. version of UP
  37. * builds. (which are NOPs on non-debug, non-preempt
  38. * builds)
  39. *
  40. * (included on UP-non-debug builds:)
  41. *
  42. * linux/spinlock_api_up.h:
  43. * builds the _spin_*() APIs.
  44. *
  45. * linux/spinlock.h: builds the final spin_*() APIs.
  46. */
  47. #include <linux/typecheck.h>
  48. #include <linux/preempt.h>
  49. #include <linux/linkage.h>
  50. #include <linux/compiler.h>
  51. #include <linux/irqflags.h>
  52. #include <linux/thread_info.h>
  53. #include <linux/kernel.h>
  54. #include <linux/stringify.h>
  55. #include <linux/bottom_half.h>
  56. #include <asm/barrier.h>
  57. /*
  58. * Must define these before including other files, inline functions need them
  59. */
  60. #define LOCK_SECTION_NAME ".text..lock."KBUILD_BASENAME
  61. #define LOCK_SECTION_START(extra) \
  62. ".subsection 1\n\t" \
  63. extra \
  64. ".ifndef " LOCK_SECTION_NAME "\n\t" \
  65. LOCK_SECTION_NAME ":\n\t" \
  66. ".endif\n"
  67. #define LOCK_SECTION_END \
  68. ".previous\n\t"
  69. #define __lockfunc __attribute__((section(".spinlock.text")))
  70. /*
  71. * Pull the arch_spinlock_t and arch_rwlock_t definitions:
  72. */
  73. #include <linux/spinlock_types.h>
  74. /*
  75. * Pull the arch_spin*() functions/declarations (UP-nondebug doesn't need them):
  76. */
  77. #ifdef CONFIG_SMP
  78. # include <asm/spinlock.h>
  79. #else
  80. # include <linux/spinlock_up.h>
  81. #endif
  82. #ifdef CONFIG_DEBUG_SPINLOCK
  83. extern void __raw_spin_lock_init(raw_spinlock_t *lock, const char *name,
  84. struct lock_class_key *key);
  85. # define raw_spin_lock_init(lock) \
  86. do { \
  87. static struct lock_class_key __key; \
  88. \
  89. __raw_spin_lock_init((lock), #lock, &__key); \
  90. } while (0)
  91. #else
  92. # define raw_spin_lock_init(lock) \
  93. do { *(lock) = __RAW_SPIN_LOCK_UNLOCKED(lock); } while (0)
  94. #endif
  95. #define raw_spin_is_locked(lock) arch_spin_is_locked(&(lock)->raw_lock)
  96. #ifdef CONFIG_GENERIC_LOCKBREAK
  97. #define raw_spin_is_contended(lock) ((lock)->break_lock)
  98. #else
  99. #ifdef arch_spin_is_contended
  100. #define raw_spin_is_contended(lock) arch_spin_is_contended(&(lock)->raw_lock)
  101. #else
  102. #define raw_spin_is_contended(lock) (((void)(lock), 0))
  103. #endif /*arch_spin_is_contended*/
  104. #endif
  105. /* The lock does not imply full memory barrier. */
  106. #ifndef ARCH_HAS_SMP_MB_AFTER_LOCK
  107. static inline void smp_mb__after_lock(void) { smp_mb(); }
  108. #endif
  109. /**
  110. * raw_spin_unlock_wait - wait until the spinlock gets unlocked
  111. * @lock: the spinlock in question.
  112. */
  113. #define raw_spin_unlock_wait(lock) arch_spin_unlock_wait(&(lock)->raw_lock)
  114. #ifdef CONFIG_DEBUG_SPINLOCK
  115. extern void do_raw_spin_lock(raw_spinlock_t *lock) __acquires(lock);
  116. #define do_raw_spin_lock_flags(lock, flags) do_raw_spin_lock(lock)
  117. extern int do_raw_spin_trylock(raw_spinlock_t *lock);
  118. extern void do_raw_spin_unlock(raw_spinlock_t *lock) __releases(lock);
  119. #else
  120. static inline void do_raw_spin_lock(raw_spinlock_t *lock) __acquires(lock)
  121. {
  122. __acquire(lock);
  123. arch_spin_lock(&lock->raw_lock);
  124. }
  125. static inline void
  126. do_raw_spin_lock_flags(raw_spinlock_t *lock, unsigned long *flags) __acquires(lock)
  127. {
  128. __acquire(lock);
  129. arch_spin_lock_flags(&lock->raw_lock, *flags);
  130. }
  131. static inline int do_raw_spin_trylock(raw_spinlock_t *lock)
  132. {
  133. return arch_spin_trylock(&(lock)->raw_lock);
  134. }
  135. static inline void do_raw_spin_unlock(raw_spinlock_t *lock) __releases(lock)
  136. {
  137. arch_spin_unlock(&lock->raw_lock);
  138. __release(lock);
  139. }
  140. #endif
  141. /*
  142. * Define the various spin_lock methods. Note we define these
  143. * regardless of whether CONFIG_SMP or CONFIG_PREEMPT are set. The
  144. * various methods are defined as nops in the case they are not
  145. * required.
  146. */
  147. #define raw_spin_trylock(lock) __cond_lock(lock, _raw_spin_trylock(lock))
  148. #define raw_spin_lock(lock) _raw_spin_lock(lock)
  149. #ifdef CONFIG_DEBUG_LOCK_ALLOC
  150. # define raw_spin_lock_nested(lock, subclass) \
  151. _raw_spin_lock_nested(lock, subclass)
  152. # define raw_spin_lock_nest_lock(lock, nest_lock) \
  153. do { \
  154. typecheck(struct lockdep_map *, &(nest_lock)->dep_map);\
  155. _raw_spin_lock_nest_lock(lock, &(nest_lock)->dep_map); \
  156. } while (0)
  157. #else
  158. # define raw_spin_lock_nested(lock, subclass) _raw_spin_lock(lock)
  159. # define raw_spin_lock_nest_lock(lock, nest_lock) _raw_spin_lock(lock)
  160. #endif
  161. #if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
  162. #define raw_spin_lock_irqsave(lock, flags) \
  163. do { \
  164. typecheck(unsigned long, flags); \
  165. flags = _raw_spin_lock_irqsave(lock); \
  166. } while (0)
  167. #ifdef CONFIG_DEBUG_LOCK_ALLOC
  168. #define raw_spin_lock_irqsave_nested(lock, flags, subclass) \
  169. do { \
  170. typecheck(unsigned long, flags); \
  171. flags = _raw_spin_lock_irqsave_nested(lock, subclass); \
  172. } while (0)
  173. #else
  174. #define raw_spin_lock_irqsave_nested(lock, flags, subclass) \
  175. do { \
  176. typecheck(unsigned long, flags); \
  177. flags = _raw_spin_lock_irqsave(lock); \
  178. } while (0)
  179. #endif
  180. #else
  181. #define raw_spin_lock_irqsave(lock, flags) \
  182. do { \
  183. typecheck(unsigned long, flags); \
  184. _raw_spin_lock_irqsave(lock, flags); \
  185. } while (0)
  186. #define raw_spin_lock_irqsave_nested(lock, flags, subclass) \
  187. raw_spin_lock_irqsave(lock, flags)
  188. #endif
  189. #define raw_spin_lock_irq(lock) _raw_spin_lock_irq(lock)
  190. #define raw_spin_lock_bh(lock) _raw_spin_lock_bh(lock)
  191. #define raw_spin_unlock(lock) _raw_spin_unlock(lock)
  192. #define raw_spin_unlock_irq(lock) _raw_spin_unlock_irq(lock)
  193. #define raw_spin_unlock_irqrestore(lock, flags) \
  194. do { \
  195. typecheck(unsigned long, flags); \
  196. _raw_spin_unlock_irqrestore(lock, flags); \
  197. } while (0)
  198. #define raw_spin_unlock_bh(lock) _raw_spin_unlock_bh(lock)
  199. #define raw_spin_trylock_bh(lock) \
  200. __cond_lock(lock, _raw_spin_trylock_bh(lock))
  201. #define raw_spin_trylock_irq(lock) \
  202. ({ \
  203. local_irq_disable(); \
  204. raw_spin_trylock(lock) ? \
  205. 1 : ({ local_irq_enable(); 0; }); \
  206. })
  207. #define raw_spin_trylock_irqsave(lock, flags) \
  208. ({ \
  209. local_irq_save(flags); \
  210. raw_spin_trylock(lock) ? \
  211. 1 : ({ local_irq_restore(flags); 0; }); \
  212. })
  213. /**
  214. * raw_spin_can_lock - would raw_spin_trylock() succeed?
  215. * @lock: the spinlock in question.
  216. */
  217. #define raw_spin_can_lock(lock) (!raw_spin_is_locked(lock))
  218. /* Include rwlock functions */
  219. #include <linux/rwlock.h>
  220. /*
  221. * Pull the _spin_*()/_read_*()/_write_*() functions/declarations:
  222. */
  223. #if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
  224. # include <linux/spinlock_api_smp.h>
  225. #else
  226. # include <linux/spinlock_api_up.h>
  227. #endif
  228. /*
  229. * Map the spin_lock functions to the raw variants for PREEMPT_RT=n
  230. */
  231. static inline raw_spinlock_t *spinlock_check(spinlock_t *lock)
  232. {
  233. return &lock->rlock;
  234. }
  235. #define spin_lock_init(_lock) \
  236. do { \
  237. spinlock_check(_lock); \
  238. raw_spin_lock_init(&(_lock)->rlock); \
  239. } while (0)
  240. static inline void spin_lock(spinlock_t *lock)
  241. {
  242. raw_spin_lock(&lock->rlock);
  243. }
  244. static inline void spin_lock_bh(spinlock_t *lock)
  245. {
  246. raw_spin_lock_bh(&lock->rlock);
  247. }
  248. static inline int spin_trylock(spinlock_t *lock)
  249. {
  250. return raw_spin_trylock(&lock->rlock);
  251. }
  252. #define spin_lock_nested(lock, subclass) \
  253. do { \
  254. raw_spin_lock_nested(spinlock_check(lock), subclass); \
  255. } while (0)
  256. #define spin_lock_nest_lock(lock, nest_lock) \
  257. do { \
  258. raw_spin_lock_nest_lock(spinlock_check(lock), nest_lock); \
  259. } while (0)
  260. static inline void spin_lock_irq(spinlock_t *lock)
  261. {
  262. raw_spin_lock_irq(&lock->rlock);
  263. }
  264. #define spin_lock_irqsave(lock, flags) \
  265. do { \
  266. raw_spin_lock_irqsave(spinlock_check(lock), flags); \
  267. } while (0)
  268. #define spin_lock_irqsave_nested(lock, flags, subclass) \
  269. do { \
  270. raw_spin_lock_irqsave_nested(spinlock_check(lock), flags, subclass); \
  271. } while (0)
  272. static inline void spin_unlock(spinlock_t *lock)
  273. {
  274. raw_spin_unlock(&lock->rlock);
  275. }
  276. static inline void spin_unlock_bh(spinlock_t *lock)
  277. {
  278. raw_spin_unlock_bh(&lock->rlock);
  279. }
  280. static inline void spin_unlock_irq(spinlock_t *lock)
  281. {
  282. raw_spin_unlock_irq(&lock->rlock);
  283. }
  284. static inline void spin_unlock_irqrestore(spinlock_t *lock, unsigned long flags)
  285. {
  286. raw_spin_unlock_irqrestore(&lock->rlock, flags);
  287. }
  288. static inline int spin_trylock_bh(spinlock_t *lock)
  289. {
  290. return raw_spin_trylock_bh(&lock->rlock);
  291. }
  292. static inline int spin_trylock_irq(spinlock_t *lock)
  293. {
  294. return raw_spin_trylock_irq(&lock->rlock);
  295. }
  296. #define spin_trylock_irqsave(lock, flags) \
  297. ({ \
  298. raw_spin_trylock_irqsave(spinlock_check(lock), flags); \
  299. })
  300. static inline void spin_unlock_wait(spinlock_t *lock)
  301. {
  302. raw_spin_unlock_wait(&lock->rlock);
  303. }
  304. static inline int spin_is_locked(spinlock_t *lock)
  305. {
  306. return raw_spin_is_locked(&lock->rlock);
  307. }
  308. static inline int spin_is_contended(spinlock_t *lock)
  309. {
  310. return raw_spin_is_contended(&lock->rlock);
  311. }
  312. static inline int spin_can_lock(spinlock_t *lock)
  313. {
  314. return raw_spin_can_lock(&lock->rlock);
  315. }
  316. #define assert_spin_locked(lock) assert_raw_spin_locked(&(lock)->rlock)
  317. /*
  318. * Pull the atomic_t declaration:
  319. * (asm-mips/atomic.h needs above definitions)
  320. */
  321. #include <linux/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. #endif /* __LINUX_SPINLOCK_H */