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/ktime.h>
  10#include <linux/wait.h>
  11#include <linux/string.h>
  12#include <linux/fs.h>
  13#include <linux/sysctl.h>
  14#include <asm/uaccess.h>
  15
  16extern struct ctl_table epoll_table[]; /* for sysctl */
  17/* ~832 bytes of stack space used max in sys_select/sys_poll before allocating
  18   additional memory. */
  19#define MAX_STACK_ALLOC 832
  20#define FRONTEND_STACK_ALLOC    256
  21#define SELECT_STACK_ALLOC      FRONTEND_STACK_ALLOC
  22#define POLL_STACK_ALLOC        FRONTEND_STACK_ALLOC
  23#define WQUEUES_STACK_ALLOC     (MAX_STACK_ALLOC - FRONTEND_STACK_ALLOC)
  24#define N_INLINE_POLL_ENTRIES   (WQUEUES_STACK_ALLOC / sizeof(struct poll_table_entry))
  25
  26#define DEFAULT_POLLMASK (POLLIN | POLLOUT | POLLRDNORM | POLLWRNORM)
  27
  28struct poll_table_struct;
  29
  30/* 
  31 * structures and helpers for f_op->poll implementations
  32 */
  33typedef void (*poll_queue_proc)(struct file *, wait_queue_head_t *, struct poll_table_struct *);
  34
  35typedef struct poll_table_struct {
  36        poll_queue_proc qproc;
  37        unsigned long key;
  38} poll_table;
  39
  40static inline void poll_wait(struct file * filp, wait_queue_head_t * wait_address, poll_table *p)
  41{
  42        if (p && wait_address)
  43                p->qproc(filp, wait_address, p);
  44}
  45
  46static inline void init_poll_funcptr(poll_table *pt, poll_queue_proc qproc)
  47{
  48        pt->qproc = qproc;
  49        pt->key   = ~0UL; /* all events enabled */
  50}
  51
  52struct poll_table_entry {
  53        struct file *filp;
  54        unsigned long key;
  55        wait_queue_t wait;
  56        wait_queue_head_t *wait_address;
  57};
  58
  59/*
  60 * Structures and helpers for select/poll syscall
  61 */
  62struct poll_wqueues {
  63        poll_table pt;
  64        struct poll_table_page *table;
  65        struct task_struct *polling_task;
  66        int triggered;
  67        int error;
  68        int inline_index;
  69        struct poll_table_entry inline_entries[N_INLINE_POLL_ENTRIES];
  70};
  71
  72extern void poll_initwait(struct poll_wqueues *pwq);
  73extern void poll_freewait(struct poll_wqueues *pwq);
  74extern int poll_schedule_timeout(struct poll_wqueues *pwq, int state,
  75                                 ktime_t *expires, unsigned long slack);
  76extern long select_estimate_accuracy(struct timespec *tv);
  77
  78
  79static inline int poll_schedule(struct poll_wqueues *pwq, int state)
  80{
  81        return poll_schedule_timeout(pwq, state, NULL, 0);
  82}
  83
  84/*
  85 * Scalable version of the fd_set.
  86 */
  87
  88typedef struct {
  89        unsigned long *in, *out, *ex;
  90        unsigned long *res_in, *res_out, *res_ex;
  91} fd_set_bits;
  92
  93/*
  94 * How many longwords for "nr" bits?
  95 */
  96#define FDS_BITPERLONG  (8*sizeof(long))
  97#define FDS_LONGS(nr)   (((nr)+FDS_BITPERLONG-1)/FDS_BITPERLONG)
  98#define FDS_BYTES(nr)   (FDS_LONGS(nr)*sizeof(long))
  99
 100/*
 101 * We do a VERIFY_WRITE here even though we are only reading this time:
 102 * we'll write to it eventually..
 103 *
 104 * Use "unsigned long" accesses to let user-mode fd_set's be long-aligned.
 105 */
 106static inline
 107int get_fd_set(unsigned long nr, void __user *ufdset, unsigned long *fdset)
 108{
 109        nr = FDS_BYTES(nr);
 110        if (ufdset)
 111                return copy_from_user(fdset, ufdset, nr) ? -EFAULT : 0;
 112
 113        memset(fdset, 0, nr);
 114        return 0;
 115}
 116
 117static inline unsigned long __must_check
 118set_fd_set(unsigned long nr, void __user *ufdset, unsigned long *fdset)
 119{
 120        if (ufdset)
 121                return __copy_to_user(ufdset, fdset, FDS_BYTES(nr));
 122        return 0;
 123}
 124
 125static inline
 126void zero_fd_set(unsigned long nr, unsigned long *fdset)
 127{
 128        memset(fdset, 0, FDS_BYTES(nr));
 129}
 130
 131#define MAX_INT64_SECONDS (((s64)(~((u64)0)>>1)/HZ)-1)
 132
 133extern int do_select(int n, fd_set_bits *fds, struct timespec *end_time);
 134extern int do_sys_poll(struct pollfd __user * ufds, unsigned int nfds,
 135                       struct timespec *end_time);
 136extern int core_sys_select(int n, fd_set __user *inp, fd_set __user *outp,
 137                           fd_set __user *exp, struct timespec *end_time);
 138
 139extern int poll_select_set_timeout(struct timespec *to, long sec, long nsec);
 140
 141#endif /* KERNEL */
 142
 143#endif /* _LINUX_POLL_H */
 144