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
23 struct poll_table_struct;
24
25 /*
26 * structures and helpers for f_op->poll implementations
27 */
28 typedef void (*poll_queue_proc)(struct file *, wait_queue_head_t *, struct poll_table_struct *);
29
30 typedef struct poll_table_struct {
31 poll_queue_proc qproc;
32 } poll_table;
33
poll_wait(struct file * filp,wait_queue_head_t * wait_address,poll_table * p)34 static 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
init_poll_funcptr(poll_table * pt,poll_queue_proc qproc)40 static inline void init_poll_funcptr(poll_table *pt, poll_queue_proc qproc)
41 {
42 pt->qproc = qproc;
43 }
44
45 struct 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 */
54 struct 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
62 extern void poll_initwait(struct poll_wqueues *pwq);
63 extern void poll_freewait(struct poll_wqueues *pwq);
64
65 /*
66 * Scaleable version of the fd_set.
67 */
68
69 typedef 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 */
87 static inline
get_fd_set(unsigned long nr,void __user * ufdset,unsigned long * fdset)88 int 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
98 static inline unsigned long __must_check
set_fd_set(unsigned long nr,void __user * ufdset,unsigned long * fdset)99 set_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
106 static inline
zero_fd_set(unsigned long nr,unsigned long * fdset)107 void 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
114 extern int do_select(int n, fd_set_bits *fds, s64 *timeout);
115 extern 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