rwlock.h 4.2 KB

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  1. #ifndef __LINUX_RWLOCK_H
  2. #define __LINUX_RWLOCK_H
  3. #ifndef __LINUX_INSIDE_SPINLOCK_H
  4. # error "please don't include this file directly"
  5. #endif
  6. /*
  7. * rwlock related methods
  8. *
  9. * split out from spinlock.h
  10. *
  11. * portions Copyright 2005, Red Hat, Inc., Ingo Molnar
  12. * Released under the General Public License (GPL).
  13. */
  14. #ifdef CONFIG_DEBUG_SPINLOCK
  15. extern void __rwlock_init(rwlock_t *lock, const char *name,
  16. struct lock_class_key *key);
  17. # define rwlock_init(lock) \
  18. do { \
  19. static struct lock_class_key __key; \
  20. \
  21. __rwlock_init((lock), #lock, &__key); \
  22. } while (0)
  23. #else
  24. # define rwlock_init(lock) \
  25. do { *(lock) = __RW_LOCK_UNLOCKED(lock); } while (0)
  26. #endif
  27. #ifdef CONFIG_DEBUG_SPINLOCK
  28. extern void do_raw_read_lock(rwlock_t *lock) __acquires(lock);
  29. extern int do_raw_read_trylock(rwlock_t *lock);
  30. extern void do_raw_read_unlock(rwlock_t *lock) __releases(lock);
  31. extern void do_raw_write_lock(rwlock_t *lock) __acquires(lock);
  32. extern int do_raw_write_trylock(rwlock_t *lock);
  33. extern void do_raw_write_unlock(rwlock_t *lock) __releases(lock);
  34. #else
  35. # define do_raw_read_lock(rwlock) do {__acquire(lock); arch_read_lock(&(rwlock)->raw_lock); } while (0)
  36. # define do_raw_read_trylock(rwlock) arch_read_trylock(&(rwlock)->raw_lock)
  37. # define do_raw_read_unlock(rwlock) do {arch_read_unlock(&(rwlock)->raw_lock); __release(lock); } while (0)
  38. # define do_raw_write_lock(rwlock) do {__acquire(lock); arch_write_lock(&(rwlock)->raw_lock); } while (0)
  39. # define do_raw_write_trylock(rwlock) arch_write_trylock(&(rwlock)->raw_lock)
  40. # define do_raw_write_unlock(rwlock) do {arch_write_unlock(&(rwlock)->raw_lock); __release(lock); } while (0)
  41. #endif
  42. /*
  43. * Define the various rw_lock methods. Note we define these
  44. * regardless of whether CONFIG_SMP or CONFIG_PREEMPT are set. The various
  45. * methods are defined as nops in the case they are not required.
  46. */
  47. #define read_trylock(lock) __cond_lock(lock, _raw_read_trylock(lock))
  48. #define write_trylock(lock) __cond_lock(lock, _raw_write_trylock(lock))
  49. #define write_lock(lock) _raw_write_lock(lock)
  50. #define read_lock(lock) _raw_read_lock(lock)
  51. #ifdef CONFIG_DEBUG_LOCK_ALLOC
  52. #define write_lock_nested(lock, subclass) _raw_write_lock_nested(lock, subclass)
  53. #else
  54. #define write_lock_nested(lock, subclass) _raw_write_lock(lock)
  55. #endif
  56. #if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
  57. #define read_lock_irqsave(lock, flags) \
  58. do { \
  59. typecheck(unsigned long, flags); \
  60. flags = _raw_read_lock_irqsave(lock); \
  61. } while (0)
  62. #define write_lock_irqsave(lock, flags) \
  63. do { \
  64. typecheck(unsigned long, flags); \
  65. flags = _raw_write_lock_irqsave(lock); \
  66. } while (0)
  67. #else
  68. #define read_lock_irqsave(lock, flags) \
  69. do { \
  70. typecheck(unsigned long, flags); \
  71. _raw_read_lock_irqsave(lock, flags); \
  72. } while (0)
  73. #define write_lock_irqsave(lock, flags) \
  74. do { \
  75. typecheck(unsigned long, flags); \
  76. _raw_write_lock_irqsave(lock, flags); \
  77. } while (0)
  78. #endif
  79. #define read_lock_irq(lock) _raw_read_lock_irq(lock)
  80. #define read_lock_bh(lock) _raw_read_lock_bh(lock)
  81. #define write_lock_irq(lock) _raw_write_lock_irq(lock)
  82. #define write_lock_bh(lock) _raw_write_lock_bh(lock)
  83. #define read_unlock(lock) _raw_read_unlock(lock)
  84. #define write_unlock(lock) _raw_write_unlock(lock)
  85. #define read_unlock_irq(lock) _raw_read_unlock_irq(lock)
  86. #define write_unlock_irq(lock) _raw_write_unlock_irq(lock)
  87. #define read_unlock_irqrestore(lock, flags) \
  88. do { \
  89. typecheck(unsigned long, flags); \
  90. _raw_read_unlock_irqrestore(lock, flags); \
  91. } while (0)
  92. #define read_unlock_bh(lock) _raw_read_unlock_bh(lock)
  93. #define write_unlock_irqrestore(lock, flags) \
  94. do { \
  95. typecheck(unsigned long, flags); \
  96. _raw_write_unlock_irqrestore(lock, flags); \
  97. } while (0)
  98. #define write_unlock_bh(lock) _raw_write_unlock_bh(lock)
  99. #define write_trylock_irqsave(lock, flags) \
  100. ({ \
  101. local_irq_save(flags); \
  102. write_trylock(lock) ? \
  103. 1 : ({ local_irq_restore(flags); 0; }); \
  104. })
  105. #ifdef arch_rwlock_is_contended
  106. #define rwlock_is_contended(lock) \
  107. arch_rwlock_is_contended(&(lock)->raw_lock)
  108. #else
  109. #define rwlock_is_contended(lock) ((void)(lock), 0)
  110. #endif /* arch_rwlock_is_contended */
  111. #endif /* __LINUX_RWLOCK_H */