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