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
26 struct poll_table_struct;
27
28 /*
29 * structures and helpers for f_op->poll implementations
30 */
31 typedef void (*poll_queue_proc)(struct file *, wait_queue_head_t *, struct poll_table_struct *);
32
33 typedef struct poll_table_struct {
34 poll_queue_proc qproc;
35 } poll_table;
36
37 static 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
43 static inline void init_poll_funcptr(poll_table *pt, poll_queue_proc qproc)
44 {
45 pt->qproc = qproc;
46 }
47
48 struct 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 */
57 struct 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
65 extern void poll_initwait(struct poll_wqueues *pwq);
66 extern void poll_freewait(struct poll_wqueues *pwq);
67
68 /*
69 * Scaleable version of the fd_set.
70 */
71
72 typedef 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 */
90 static inline
91 int 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
101 static inline unsigned long __must_check
102 set_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
109 static inline
110 void 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
117 extern int do_select(int n, fd_set_bits *fds, s64 *timeout);
118 extern int do_sys_poll(struct pollfd __user * ufds, unsigned int nfds,
119 s64 *timeout);
120
121 #endif /* KERNEL */
122
123 #endif /* _LINUX_POLL_H */
124
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