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b2441318 | 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
1da177e4 LT |
2 | #ifndef _LINUX_POLL_H |
3 | #define _LINUX_POLL_H | |
4 | ||
1da177e4 LT |
5 | |
6 | #include <linux/compiler.h> | |
a99bbaf5 | 7 | #include <linux/ktime.h> |
1da177e4 LT |
8 | #include <linux/wait.h> |
9 | #include <linux/string.h> | |
f23f6e08 | 10 | #include <linux/fs.h> |
9ff99339 | 11 | #include <linux/sysctl.h> |
7c0f6ba6 | 12 | #include <linux/uaccess.h> |
607ca46e | 13 | #include <uapi/linux/poll.h> |
1da177e4 | 14 | |
9ff99339 | 15 | extern struct ctl_table epoll_table[]; /* for sysctl */ |
70674f95 AK |
16 | /* ~832 bytes of stack space used max in sys_select/sys_poll before allocating |
17 | additional memory. */ | |
18 | #define MAX_STACK_ALLOC 832 | |
19 | #define FRONTEND_STACK_ALLOC 256 | |
20 | #define SELECT_STACK_ALLOC FRONTEND_STACK_ALLOC | |
21 | #define POLL_STACK_ALLOC FRONTEND_STACK_ALLOC | |
22 | #define WQUEUES_STACK_ALLOC (MAX_STACK_ALLOC - FRONTEND_STACK_ALLOC) | |
23 | #define N_INLINE_POLL_ENTRIES (WQUEUES_STACK_ALLOC / sizeof(struct poll_table_entry)) | |
24 | ||
dd23aae4 AD |
25 | #define DEFAULT_POLLMASK (POLLIN | POLLOUT | POLLRDNORM | POLLWRNORM) |
26 | ||
1da177e4 LT |
27 | struct poll_table_struct; |
28 | ||
29 | /* | |
30 | * structures and helpers for f_op->poll implementations | |
31 | */ | |
32 | typedef void (*poll_queue_proc)(struct file *, wait_queue_head_t *, struct poll_table_struct *); | |
33 | ||
626cf236 HV |
34 | /* |
35 | * Do not touch the structure directly, use the access functions | |
36 | * poll_does_not_wait() and poll_requested_events() instead. | |
37 | */ | |
1da177e4 | 38 | typedef struct poll_table_struct { |
626cf236 HV |
39 | poll_queue_proc _qproc; |
40 | unsigned long _key; | |
1da177e4 LT |
41 | } poll_table; |
42 | ||
43 | static inline void poll_wait(struct file * filp, wait_queue_head_t * wait_address, poll_table *p) | |
44 | { | |
626cf236 HV |
45 | if (p && p->_qproc && wait_address) |
46 | p->_qproc(filp, wait_address, p); | |
47 | } | |
48 | ||
49 | /* | |
50 | * Return true if it is guaranteed that poll will not wait. This is the case | |
51 | * if the poll() of another file descriptor in the set got an event, so there | |
52 | * is no need for waiting. | |
53 | */ | |
54 | static inline bool poll_does_not_wait(const poll_table *p) | |
55 | { | |
56 | return p == NULL || p->_qproc == NULL; | |
57 | } | |
58 | ||
59 | /* | |
60 | * Return the set of events that the application wants to poll for. | |
61 | * This is useful for drivers that need to know whether a DMA transfer has | |
62 | * to be started implicitly on poll(). You typically only want to do that | |
63 | * if the application is actually polling for POLLIN and/or POLLOUT. | |
64 | */ | |
65 | static inline unsigned long poll_requested_events(const poll_table *p) | |
66 | { | |
67 | return p ? p->_key : ~0UL; | |
1da177e4 LT |
68 | } |
69 | ||
70 | static inline void init_poll_funcptr(poll_table *pt, poll_queue_proc qproc) | |
71 | { | |
626cf236 HV |
72 | pt->_qproc = qproc; |
73 | pt->_key = ~0UL; /* all events enabled */ | |
1da177e4 LT |
74 | } |
75 | ||
70674f95 | 76 | struct poll_table_entry { |
5f820f64 | 77 | struct file *filp; |
4938d7e0 | 78 | unsigned long key; |
ac6424b9 | 79 | wait_queue_entry_t wait; |
5f820f64 | 80 | wait_queue_head_t *wait_address; |
70674f95 AK |
81 | }; |
82 | ||
1da177e4 | 83 | /* |
dac36dd8 | 84 | * Structures and helpers for select/poll syscall |
1da177e4 LT |
85 | */ |
86 | struct poll_wqueues { | |
87 | poll_table pt; | |
5f820f64 TH |
88 | struct poll_table_page *table; |
89 | struct task_struct *polling_task; | |
90 | int triggered; | |
1da177e4 | 91 | int error; |
70674f95 AK |
92 | int inline_index; |
93 | struct poll_table_entry inline_entries[N_INLINE_POLL_ENTRIES]; | |
1da177e4 LT |
94 | }; |
95 | ||
96 | extern void poll_initwait(struct poll_wqueues *pwq); | |
97 | extern void poll_freewait(struct poll_wqueues *pwq); | |
5f820f64 TH |
98 | extern int poll_schedule_timeout(struct poll_wqueues *pwq, int state, |
99 | ktime_t *expires, unsigned long slack); | |
766b9f92 | 100 | extern u64 select_estimate_accuracy(struct timespec64 *tv); |
95aac7b1 | 101 | |
9f72949f DW |
102 | #define MAX_INT64_SECONDS (((s64)(~((u64)0)>>1)/HZ)-1) |
103 | ||
a2dcb44c | 104 | extern int core_sys_select(int n, fd_set __user *inp, fd_set __user *outp, |
766b9f92 | 105 | fd_set __user *exp, struct timespec64 *end_time); |
1da177e4 | 106 | |
766b9f92 DD |
107 | extern int poll_select_set_timeout(struct timespec64 *to, time64_t sec, |
108 | long nsec); | |
b773ad40 | 109 | |
1da177e4 | 110 | #endif /* _LINUX_POLL_H */ |