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