linux/include/linux/poll.h

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _LINUX_POLL_H
#define _LINUX_POLL_H


#include <linux/compiler.h>
#include <linux/ktime.h>
#include <linux/wait.h>
#include <linux/string.h>
#include <linux/fs.h>
#include <linux/uaccess.h>
#include <uapi/linux/poll.h>
#include <uapi/linux/eventpoll.h>

/* ~832 bytes of stack space used max in sys_select/sys_poll before allocating
   additional memory. */
#define MAX_STACK_ALLOC …
#define FRONTEND_STACK_ALLOC …
#define SELECT_STACK_ALLOC …
#define POLL_STACK_ALLOC …
#define WQUEUES_STACK_ALLOC …
#define N_INLINE_POLL_ENTRIES …

#define DEFAULT_POLLMASK …

struct poll_table_struct;

/* 
 * structures and helpers for f_op->poll implementations
 */
poll_queue_proc;

/*
 * Do not touch the structure directly, use the access functions
 * poll_does_not_wait() and poll_requested_events() instead.
 */
poll_table;

static inline void poll_wait(struct file * filp, wait_queue_head_t * wait_address, poll_table *p)
{ … }

/*
 * Return true if it is guaranteed that poll will not wait. This is the case
 * if the poll() of another file descriptor in the set got an event, so there
 * is no need for waiting.
 */
static inline bool poll_does_not_wait(const poll_table *p)
{ … }

/*
 * Return the set of events that the application wants to poll for.
 * This is useful for drivers that need to know whether a DMA transfer has
 * to be started implicitly on poll(). You typically only want to do that
 * if the application is actually polling for POLLIN and/or POLLOUT.
 */
static inline __poll_t poll_requested_events(const poll_table *p)
{ … }

static inline void init_poll_funcptr(poll_table *pt, poll_queue_proc qproc)
{ … }

static inline bool file_can_poll(struct file *file)
{ … }

static inline __poll_t vfs_poll(struct file *file, struct poll_table_struct *pt)
{ … }

struct poll_table_entry { … };

/*
 * Structures and helpers for select/poll syscall
 */
struct poll_wqueues { … };

extern void poll_initwait(struct poll_wqueues *pwq);
extern void poll_freewait(struct poll_wqueues *pwq);
extern u64 select_estimate_accuracy(struct timespec64 *tv);

#define MAX_INT64_SECONDS …

extern int core_sys_select(int n, fd_set __user *inp, fd_set __user *outp,
			   fd_set __user *exp, struct timespec64 *end_time);

extern int poll_select_set_timeout(struct timespec64 *to, time64_t sec,
				   long nsec);

#define __MAP(v, from, to) …

static inline __u16 mangle_poll(__poll_t val)
{ … }

static inline __poll_t demangle_poll(u16 val)
{ … }
#undef __MAP


#endif /* _LINUX_POLL_H */