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