Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
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
24struct poll_table_struct;
25
26/*
27 * structures and helpers for f_op->poll implementations
28 */
29typedef void (*poll_queue_proc)(struct file *, wait_queue_head_t *, struct poll_table_struct *);
30
31typedef struct poll_table_struct {
32 poll_queue_proc qproc;
33} poll_table;
34
35static inline void poll_wait(struct file * filp, wait_queue_head_t * wait_address, poll_table *p)
36{
37 if (p && wait_address)
38 p->qproc(filp, wait_address, p);
39}
40
41static inline void init_poll_funcptr(poll_table *pt, poll_queue_proc qproc)
42{
43 pt->qproc = qproc;
44}
45
46struct poll_table_entry {
47 struct file * filp;
48 wait_queue_t wait;
49 wait_queue_head_t * wait_address;
50};
51
52/*
53 * Structures and helpers for sys_poll/sys_poll
54 */
55struct poll_wqueues {
56 poll_table pt;
57 struct poll_table_page * table;
58 int error;
59 int inline_index;
60 struct poll_table_entry inline_entries[N_INLINE_POLL_ENTRIES];
61};
62
63extern void poll_initwait(struct poll_wqueues *pwq);
64extern void poll_freewait(struct poll_wqueues *pwq);
65
66/*
67 * Scaleable version of the fd_set.
68 */
69
70typedef struct {
71 unsigned long *in, *out, *ex;
72 unsigned long *res_in, *res_out, *res_ex;
73} fd_set_bits;
74
75/*
76 * How many longwords for "nr" bits?
77 */
78#define FDS_BITPERLONG (8*sizeof(long))
79#define FDS_LONGS(nr) (((nr)+FDS_BITPERLONG-1)/FDS_BITPERLONG)
80#define FDS_BYTES(nr) (FDS_LONGS(nr)*sizeof(long))
81
82/*
83 * We do a VERIFY_WRITE here even though we are only reading this time:
84 * we'll write to it eventually..
85 *
86 * Use "unsigned long" accesses to let user-mode fd_set's be long-aligned.
87 */
88static inline
89int get_fd_set(unsigned long nr, void __user *ufdset, unsigned long *fdset)
90{
91 nr = FDS_BYTES(nr);
92 if (ufdset)
93 return copy_from_user(fdset, ufdset, nr) ? -EFAULT : 0;
94
95 memset(fdset, 0, nr);
96 return 0;
97}
98
99static inline unsigned long __must_check
100set_fd_set(unsigned long nr, void __user *ufdset, unsigned long *fdset)
101{
102 if (ufdset)
103 return __copy_to_user(ufdset, fdset, FDS_BYTES(nr));
104 return 0;
105}
106
107static inline
108void zero_fd_set(unsigned long nr, unsigned long *fdset)
109{
110 memset(fdset, 0, FDS_BYTES(nr));
111}
112
113#define MAX_INT64_SECONDS (((s64)(~((u64)0)>>1)/HZ)-1)
114
115extern int do_select(int n, fd_set_bits *fds, s64 *timeout);
116extern int do_sys_poll(struct pollfd __user * ufds, unsigned int nfds,
117 s64 *timeout);
118
119#endif /* KERNEL */
120
121#endif /* _LINUX_POLL_H */