Greg Kroah-Hartman | b244131 | 2017-11-01 15:07:57 +0100 | [diff] [blame] | 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2 | #ifndef _LINUX_POLL_H |
| 3 | #define _LINUX_POLL_H |
| 4 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5 | |
| 6 | #include <linux/compiler.h> |
Alexey Dobriyan | a99bbaf | 2009-10-04 16:11:37 +0400 | [diff] [blame] | 7 | #include <linux/ktime.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 8 | #include <linux/wait.h> |
| 9 | #include <linux/string.h> |
Al Viro | f23f6e0 | 2006-10-20 15:17:02 -0400 | [diff] [blame] | 10 | #include <linux/fs.h> |
Dave Young | 9ff9933 | 2010-03-10 15:24:10 -0800 | [diff] [blame] | 11 | #include <linux/sysctl.h> |
Linus Torvalds | 7c0f6ba | 2016-12-24 11:46:01 -0800 | [diff] [blame] | 12 | #include <linux/uaccess.h> |
David Howells | 607ca46 | 2012-10-13 10:46:48 +0100 | [diff] [blame] | 13 | #include <uapi/linux/poll.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 14 | |
Dave Young | 9ff9933 | 2010-03-10 15:24:10 -0800 | [diff] [blame] | 15 | extern struct ctl_table epoll_table[]; /* for sysctl */ |
Andi Kleen | 70674f9 | 2006-03-28 01:56:33 -0800 | [diff] [blame] | 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 | |
Alexey Dobriyan | dd23aae | 2007-09-11 15:23:55 -0700 | [diff] [blame] | 25 | #define DEFAULT_POLLMASK (POLLIN | POLLOUT | POLLRDNORM | POLLWRNORM) |
| 26 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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 | |
Hans Verkuil | 626cf23 | 2012-03-23 15:02:27 -0700 | [diff] [blame] | 34 | /* |
| 35 | * Do not touch the structure directly, use the access functions |
| 36 | * poll_does_not_wait() and poll_requested_events() instead. |
| 37 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 38 | typedef struct poll_table_struct { |
Hans Verkuil | 626cf23 | 2012-03-23 15:02:27 -0700 | [diff] [blame] | 39 | poll_queue_proc _qproc; |
| 40 | unsigned long _key; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 41 | } poll_table; |
| 42 | |
| 43 | static inline void poll_wait(struct file * filp, wait_queue_head_t * wait_address, poll_table *p) |
| 44 | { |
Hans Verkuil | 626cf23 | 2012-03-23 15:02:27 -0700 | [diff] [blame] | 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; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 68 | } |
| 69 | |
| 70 | static inline void init_poll_funcptr(poll_table *pt, poll_queue_proc qproc) |
| 71 | { |
Hans Verkuil | 626cf23 | 2012-03-23 15:02:27 -0700 | [diff] [blame] | 72 | pt->_qproc = qproc; |
| 73 | pt->_key = ~0UL; /* all events enabled */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 74 | } |
| 75 | |
Andi Kleen | 70674f9 | 2006-03-28 01:56:33 -0800 | [diff] [blame] | 76 | struct poll_table_entry { |
Tejun Heo | 5f820f6 | 2009-01-06 14:40:59 -0800 | [diff] [blame] | 77 | struct file *filp; |
Eric Dumazet | 4938d7e | 2009-06-16 15:33:36 -0700 | [diff] [blame] | 78 | unsigned long key; |
Ingo Molnar | ac6424b | 2017-06-20 12:06:13 +0200 | [diff] [blame] | 79 | wait_queue_entry_t wait; |
Tejun Heo | 5f820f6 | 2009-01-06 14:40:59 -0800 | [diff] [blame] | 80 | wait_queue_head_t *wait_address; |
Andi Kleen | 70674f9 | 2006-03-28 01:56:33 -0800 | [diff] [blame] | 81 | }; |
| 82 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 83 | /* |
Namhyung Kim | dac36dd | 2010-12-10 01:57:07 +0900 | [diff] [blame] | 84 | * Structures and helpers for select/poll syscall |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 85 | */ |
| 86 | struct poll_wqueues { |
| 87 | poll_table pt; |
Tejun Heo | 5f820f6 | 2009-01-06 14:40:59 -0800 | [diff] [blame] | 88 | struct poll_table_page *table; |
| 89 | struct task_struct *polling_task; |
| 90 | int triggered; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 91 | int error; |
Andi Kleen | 70674f9 | 2006-03-28 01:56:33 -0800 | [diff] [blame] | 92 | int inline_index; |
| 93 | struct poll_table_entry inline_entries[N_INLINE_POLL_ENTRIES]; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 94 | }; |
| 95 | |
| 96 | extern void poll_initwait(struct poll_wqueues *pwq); |
| 97 | extern void poll_freewait(struct poll_wqueues *pwq); |
Tejun Heo | 5f820f6 | 2009-01-06 14:40:59 -0800 | [diff] [blame] | 98 | extern int poll_schedule_timeout(struct poll_wqueues *pwq, int state, |
| 99 | ktime_t *expires, unsigned long slack); |
Deepa Dinamani | 766b9f9 | 2016-05-19 17:09:05 -0700 | [diff] [blame] | 100 | extern u64 select_estimate_accuracy(struct timespec64 *tv); |
Shawn Bohrer | 95aac7b | 2010-10-27 15:34:54 -0700 | [diff] [blame] | 101 | |
David Woodhouse | 9f72949 | 2006-01-18 17:44:05 -0800 | [diff] [blame] | 102 | #define MAX_INT64_SECONDS (((s64)(~((u64)0)>>1)/HZ)-1) |
| 103 | |
Al Viro | a2dcb44 | 2008-04-23 14:05:15 -0400 | [diff] [blame] | 104 | extern int core_sys_select(int n, fd_set __user *inp, fd_set __user *outp, |
Deepa Dinamani | 766b9f9 | 2016-05-19 17:09:05 -0700 | [diff] [blame] | 105 | fd_set __user *exp, struct timespec64 *end_time); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 106 | |
Deepa Dinamani | 766b9f9 | 2016-05-19 17:09:05 -0700 | [diff] [blame] | 107 | extern int poll_select_set_timeout(struct timespec64 *to, time64_t sec, |
| 108 | long nsec); |
Thomas Gleixner | b773ad4 | 2008-08-31 08:16:57 -0700 | [diff] [blame] | 109 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 110 | #endif /* _LINUX_POLL_H */ |