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        int error;
  61        int inline_index;
  62        struct poll_table_entry inline_entries[N_INLINE_POLL_ENTRIES];
  63};
  64
  65extern void poll_initwait(struct poll_wqueues *pwq);
  66extern void poll_freewait(struct poll_wqueues *pwq);
  67
  68/*
  69 * Scaleable version of the fd_set.
  70 */
  71
  72typedef struct {
  73        unsigned long *in, *out, *ex;
  74        unsigned long *res_in, *res_out, *res_ex;
  75} fd_set_bits;
  76
  77/*
  78 * How many longwords for "nr" bits?
  79 */
  80#define FDS_BITPERLONG  (8*sizeof(long))
  81#define FDS_LONGS(nr)   (((nr)+FDS_BITPERLONG-1)/FDS_BITPERLONG)
  82#define FDS_BYTES(nr)   (FDS_LONGS(nr)*sizeof(long))
  83
  84/*
  85 * We do a VERIFY_WRITE here even though we are only reading this time:
  86 * we'll write to it eventually..
  87 *
  88 * Use "unsigned long" accesses to let user-mode fd_set's be long-aligned.
  89 */
  90static inline
  91int get_fd_set(unsigned long nr, void __user *ufdset, unsigned long *fdset)
  92{
  93        nr = FDS_BYTES(nr);
  94        if (ufdset)
  95                return copy_from_user(fdset, ufdset, nr) ? -EFAULT : 0;
  96
  97        memset(fdset, 0, nr);
  98        return 0;
  99}
 100
 101static inline unsigned long __must_check
 102set_fd_set(unsigned long nr, void __user *ufdset, unsigned long *fdset)
 103{
 104        if (ufdset)
 105                return __copy_to_user(ufdset, fdset, FDS_BYTES(nr));
 106        return 0;
 107}
 108
 109static inline
 110void zero_fd_set(unsigned long nr, unsigned long *fdset)
 111{
 112        memset(fdset, 0, FDS_BYTES(nr));
 113}
 114
 115#define MAX_INT64_SECONDS (((s64)(~((u64)0)>>1)/HZ)-1)
 116
 117extern int do_select(int n, fd_set_bits *fds, s64 *timeout);
 118extern int do_sys_poll(struct pollfd __user * ufds, unsigned int nfds,
 119                       s64 *timeout);
 120extern int core_sys_select(int n, fd_set __user *inp, fd_set __user *outp,
 121                           fd_set __user *exp, s64 *timeout);
 122
 123#endif /* KERNEL */
 124
 125#endif /* _LINUX_POLL_H */
 126