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rwsem.h
资源名称：linux-2.4.20.tar.gz　[点击查看]
上传用户：jlfgdled
上传日期：2013-04-10
资源大小：33168k
文件大小：2k
源码类别：

Linux/Unix编程

开发平台：

Unix_Linux

rwsem.h：源码内容
  1. /* rwsem.h: R/W semaphores, public interface
  2.  *
  3.  * Written by David Howells (dhowells@redhat.com).
  4.  * Derived from asm-i386/semaphore.h
  5.  *
  6.  * Trylock by Brian Watson (Brian.J.Watson@compaq.com).
  7.  */
  9. #ifndef _LINUX_RWSEM_H
  10. #define _LINUX_RWSEM_H
  12. #include <linux/linkage.h>
  14. #define RWSEM_DEBUG 0
  16. #ifdef __KERNEL__
  18. #include <linux/config.h>
  19. #include <linux/types.h>
  20. #include <linux/kernel.h>
  21. #include <asm/system.h>
  22. #include <asm/atomic.h>
  24. struct rw_semaphore;
  26. #ifdef CONFIG_RWSEM_GENERIC_SPINLOCK
  27. #include <linux/rwsem-spinlock.h> /* use a generic implementation */
  28. #else
  29. #include <asm/rwsem.h> /* use an arch-specific implementation */
  30. #endif
  32. #ifndef rwsemtrace
  33. #if RWSEM_DEBUG
  34. extern void FASTCALL(rwsemtrace(struct rw_semaphore *sem, const char *str));
  35. #else
  36. #define rwsemtrace(SEM,FMT)
  37. #endif
  38. #endif
  40. /*
  41.  * lock for reading
  42.  */
  43. static inline void down_read(struct rw_semaphore *sem)
  44. {
  45. rwsemtrace(sem,"Entering down_read");
  46. __down_read(sem);
  47. rwsemtrace(sem,"Leaving down_read");
  48. }
  50. /*
  51.  * trylock for reading -- returns 1 if successful, 0 if contention
  52.  */
  53. static inline int down_read_trylock(struct rw_semaphore *sem)
  54. {
  55. int ret;
  56. rwsemtrace(sem,"Entering down_read_trylock");
  57. ret = __down_read_trylock(sem);
  58. rwsemtrace(sem,"Leaving down_read_trylock");
  59. return ret;
  60. }
  62. /*
  63.  * lock for writing
  64.  */
  65. static inline void down_write(struct rw_semaphore *sem)
  66. {
  67. rwsemtrace(sem,"Entering down_write");
  68. __down_write(sem);
  69. rwsemtrace(sem,"Leaving down_write");
  70. }
  72. /*
  73.  * trylock for writing -- returns 1 if successful, 0 if contention
  74.  */
  75. static inline int down_write_trylock(struct rw_semaphore *sem)
  76. {
  77. int ret;
  78. rwsemtrace(sem,"Entering down_write_trylock");
  79. ret = __down_write_trylock(sem);
  80. rwsemtrace(sem,"Leaving down_write_trylock");
  81. return ret;
  82. }
  84. /*
  85.  * release a read lock
  86.  */
  87. static inline void up_read(struct rw_semaphore *sem)
  88. {
  89. rwsemtrace(sem,"Entering up_read");
  90. __up_read(sem);
  91. rwsemtrace(sem,"Leaving up_read");
  92. }
  94. /*
  95.  * release a write lock
  96.  */
  97. static inline void up_write(struct rw_semaphore *sem)
  98. {
  99. rwsemtrace(sem,"Entering up_write");
  100. __up_write(sem);
  101. rwsemtrace(sem,"Leaving up_write");
  102. }
  105. #endif /* __KERNEL__ */
  106. #endif /* _LINUX_RWSEM_H */