poll.h 2.9 KB

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121
  1. #ifndef _LINUX_POLL_H
  2. #define _LINUX_POLL_H
  3. #include <asm/poll.h>
  4. #ifdef __KERNEL__
  5. #include <linux/compiler.h>
  6. #include <linux/wait.h>
  7. #include <linux/string.h>
  8. #include <linux/fs.h>
  9. #include <linux/sched.h>
  10. #include <asm/uaccess.h>
  11. /* ~832 bytes of stack space used max in sys_select/sys_poll before allocating
  12. additional memory. */
  13. #define MAX_STACK_ALLOC 832
  14. #define FRONTEND_STACK_ALLOC 256
  15. #define SELECT_STACK_ALLOC FRONTEND_STACK_ALLOC
  16. #define POLL_STACK_ALLOC FRONTEND_STACK_ALLOC
  17. #define WQUEUES_STACK_ALLOC (MAX_STACK_ALLOC - FRONTEND_STACK_ALLOC)
  18. #define N_INLINE_POLL_ENTRIES (WQUEUES_STACK_ALLOC / sizeof(struct poll_table_entry))
  19. struct poll_table_struct;
  20. /*
  21. * structures and helpers for f_op->poll implementations
  22. */
  23. typedef void (*poll_queue_proc)(struct file *, wait_queue_head_t *, struct poll_table_struct *);
  24. typedef struct poll_table_struct {
  25. poll_queue_proc qproc;
  26. } poll_table;
  27. static inline void poll_wait(struct file * filp, wait_queue_head_t * wait_address, poll_table *p)
  28. {
  29. if (p && wait_address)
  30. p->qproc(filp, wait_address, p);
  31. }
  32. static inline void init_poll_funcptr(poll_table *pt, poll_queue_proc qproc)
  33. {
  34. pt->qproc = qproc;
  35. }
  36. struct poll_table_entry {
  37. struct file * filp;
  38. wait_queue_t wait;
  39. wait_queue_head_t * wait_address;
  40. };
  41. /*
  42. * Structures and helpers for sys_poll/sys_poll
  43. */
  44. struct poll_wqueues {
  45. poll_table pt;
  46. struct poll_table_page * table;
  47. int error;
  48. int inline_index;
  49. struct poll_table_entry inline_entries[N_INLINE_POLL_ENTRIES];
  50. };
  51. extern void poll_initwait(struct poll_wqueues *pwq);
  52. extern void poll_freewait(struct poll_wqueues *pwq);
  53. /*
  54. * Scaleable version of the fd_set.
  55. */
  56. typedef struct {
  57. unsigned long *in, *out, *ex;
  58. unsigned long *res_in, *res_out, *res_ex;
  59. } fd_set_bits;
  60. /*
  61. * How many longwords for "nr" bits?
  62. */
  63. #define FDS_BITPERLONG (8*sizeof(long))
  64. #define FDS_LONGS(nr) (((nr)+FDS_BITPERLONG-1)/FDS_BITPERLONG)
  65. #define FDS_BYTES(nr) (FDS_LONGS(nr)*sizeof(long))
  66. /*
  67. * We do a VERIFY_WRITE here even though we are only reading this time:
  68. * we'll write to it eventually..
  69. *
  70. * Use "unsigned long" accesses to let user-mode fd_set's be long-aligned.
  71. */
  72. static inline
  73. int get_fd_set(unsigned long nr, void __user *ufdset, unsigned long *fdset)
  74. {
  75. nr = FDS_BYTES(nr);
  76. if (ufdset)
  77. return copy_from_user(fdset, ufdset, nr) ? -EFAULT : 0;
  78. memset(fdset, 0, nr);
  79. return 0;
  80. }
  81. static inline unsigned long __must_check
  82. set_fd_set(unsigned long nr, void __user *ufdset, unsigned long *fdset)
  83. {
  84. if (ufdset)
  85. return __copy_to_user(ufdset, fdset, FDS_BYTES(nr));
  86. return 0;
  87. }
  88. static inline
  89. void zero_fd_set(unsigned long nr, unsigned long *fdset)
  90. {
  91. memset(fdset, 0, FDS_BYTES(nr));
  92. }
  93. #define MAX_INT64_SECONDS (((s64)(~((u64)0)>>1)/HZ)-1)
  94. extern int do_select(int n, fd_set_bits *fds, s64 *timeout);
  95. extern int do_sys_poll(struct pollfd __user * ufds, unsigned int nfds,
  96. s64 *timeout);
  97. #endif /* KERNEL */
  98. #endif /* _LINUX_POLL_H */