xref: /linux-6.15/include/linux/poll.h (revision 4bedea94)
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 struct poll_table_struct;
15 
16 /*
17  * structures and helpers for f_op->poll implementations
18  */
19 typedef void (*poll_queue_proc)(struct file *, wait_queue_head_t *, struct poll_table_struct *);
20 
21 typedef struct poll_table_struct {
22 	poll_queue_proc qproc;
23 } poll_table;
24 
25 static inline void poll_wait(struct file * filp, wait_queue_head_t * wait_address, poll_table *p)
26 {
27 	if (p && wait_address)
28 		p->qproc(filp, wait_address, p);
29 }
30 
31 static inline void init_poll_funcptr(poll_table *pt, poll_queue_proc qproc)
32 {
33 	pt->qproc = qproc;
34 }
35 
36 /*
37  * Structures and helpers for sys_poll/sys_poll
38  */
39 struct poll_wqueues {
40 	poll_table pt;
41 	struct poll_table_page * table;
42 	int error;
43 };
44 
45 extern void poll_initwait(struct poll_wqueues *pwq);
46 extern void poll_freewait(struct poll_wqueues *pwq);
47 
48 /*
49  * Scaleable version of the fd_set.
50  */
51 
52 typedef struct {
53 	unsigned long *in, *out, *ex;
54 	unsigned long *res_in, *res_out, *res_ex;
55 } fd_set_bits;
56 
57 /*
58  * How many longwords for "nr" bits?
59  */
60 #define FDS_BITPERLONG	(8*sizeof(long))
61 #define FDS_LONGS(nr)	(((nr)+FDS_BITPERLONG-1)/FDS_BITPERLONG)
62 #define FDS_BYTES(nr)	(FDS_LONGS(nr)*sizeof(long))
63 
64 /*
65  * We do a VERIFY_WRITE here even though we are only reading this time:
66  * we'll write to it eventually..
67  *
68  * Use "unsigned long" accesses to let user-mode fd_set's be long-aligned.
69  */
70 static inline
71 int get_fd_set(unsigned long nr, void __user *ufdset, unsigned long *fdset)
72 {
73 	nr = FDS_BYTES(nr);
74 	if (ufdset)
75 		return copy_from_user(fdset, ufdset, nr) ? -EFAULT : 0;
76 
77 	memset(fdset, 0, nr);
78 	return 0;
79 }
80 
81 static inline unsigned long __must_check
82 set_fd_set(unsigned long nr, void __user *ufdset, unsigned long *fdset)
83 {
84 	if (ufdset)
85 		return __copy_to_user(ufdset, fdset, FDS_BYTES(nr));
86 	return 0;
87 }
88 
89 static inline
90 void zero_fd_set(unsigned long nr, unsigned long *fdset)
91 {
92 	memset(fdset, 0, FDS_BYTES(nr));
93 }
94 
95 extern int do_select(int n, fd_set_bits *fds, long *timeout);
96 
97 #endif /* KERNEL */
98 
99 #endif /* _LINUX_POLL_H */
100