LXR linux/include/linux/poll.h

   1#ifndef _LINUX_POLL_H
   2#define _LINUX_POLL_H
   3
   4#include <asm/poll.h>
   5
   6#ifdef __KERNEL__
   7
   8#include <linux/compiler.h>
   9#include <linux/wait.h>
  10#include <linux/string.h>
  11#include <linux/mm.h>
  12#include <asm/uaccess.h>
  13
  14/* ~832 bytes of stack space used max in sys_select/sys_poll before allocating
  15   additional memory. */
  16#define MAX_STACK_ALLOC 832
  17#define FRONTEND_STACK_ALLOC    256
  18#define SELECT_STACK_ALLOC      FRONTEND_STACK_ALLOC
  19#define POLL_STACK_ALLOC        FRONTEND_STACK_ALLOC
  20#define WQUEUES_STACK_ALLOC     (MAX_STACK_ALLOC - FRONTEND_STACK_ALLOC)
  21#define N_INLINE_POLL_ENTRIES   (WQUEUES_STACK_ALLOC / sizeof(struct poll_table_entry))
  22
  23struct poll_table_struct;
  24
  25/* 
  26 * structures and helpers for f_op->poll implementations
  27 */
  28typedef void (*poll_queue_proc)(struct file *, wait_queue_head_t *, struct poll_table_struct *);
  29
  30typedef struct poll_table_struct {
  31        poll_queue_proc qproc;
  32} poll_table;
  33
  34static inline void poll_wait(struct file * filp, wait_queue_head_t * wait_address, poll_table *p)
  35{
  36        if (p && wait_address)
  37                p->qproc(filp, wait_address, p);
  38}
  39
  40static inline void init_poll_funcptr(poll_table *pt, poll_queue_proc qproc)
  41{
  42        pt->qproc = qproc;
  43}
  44
  45struct poll_table_entry {
  46        struct file * filp;
  47        wait_queue_t wait;
  48        wait_queue_head_t * wait_address;
  49};
  50
  51/*
  52 * Structures and helpers for sys_poll/sys_poll
  53 */
  54struct poll_wqueues {
  55        poll_table pt;
  56        struct poll_table_page * table;
  57        int error;
  58        int inline_index;
  59        struct poll_table_entry inline_entries[N_INLINE_POLL_ENTRIES];
  60};
  61
  62extern void poll_initwait(struct poll_wqueues *pwq);
  63extern void poll_freewait(struct poll_wqueues *pwq);
  64
  65/*
  66 * Scaleable version of the fd_set.
  67 */
  68
  69typedef struct {
  70        unsigned long *in, *out, *ex;
  71        unsigned long *res_in, *res_out, *res_ex;
  72} fd_set_bits;
  73
  74/*
  75 * How many longwords for "nr" bits?
  76 */
  77#define FDS_BITPERLONG  (8*sizeof(long))
  78#define FDS_LONGS(nr)   (((nr)+FDS_BITPERLONG-1)/FDS_BITPERLONG)
  79#define FDS_BYTES(nr)   (FDS_LONGS(nr)*sizeof(long))
  80
  81/*
  82 * We do a VERIFY_WRITE here even though we are only reading this time:
  83 * we'll write to it eventually..
  84 *
  85 * Use "unsigned long" accesses to let user-mode fd_set's be long-aligned.
  86 */
  87static inline
  88int get_fd_set(unsigned long nr, void __user *ufdset, unsigned long *fdset)
  89{
  90        nr = FDS_BYTES(nr);
  91        if (ufdset)
  92                return copy_from_user(fdset, ufdset, nr) ? -EFAULT : 0;
  93
  94        memset(fdset, 0, nr);
  95        return 0;
  96}
  97
  98static inline unsigned long __must_check
  99set_fd_set(unsigned long nr, void __user *ufdset, unsigned long *fdset)
 100{
 101        if (ufdset)
 102                return __copy_to_user(ufdset, fdset, FDS_BYTES(nr));
 103        return 0;
 104}
 105
 106static inline
 107void zero_fd_set(unsigned long nr, unsigned long *fdset)
 108{
 109        memset(fdset, 0, FDS_BYTES(nr));
 110}
 111
 112#define MAX_INT64_SECONDS (((s64)(~((u64)0)>>1)/HZ)-1)
 113
 114extern int do_select(int n, fd_set_bits *fds, s64 *timeout);
 115extern int do_sys_poll(struct pollfd __user * ufds, unsigned int nfds,
 116                       s64 *timeout);
 117
 118#endif /* KERNEL */
 119
 120#endif /* _LINUX_POLL_H */
 121