blob: 2889f09a1c6080523ebf7179d337868d4610763b [file] [log] [blame]
#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/sysctl.h>
#include <linux/uaccess.h>
#include <uapi/linux/poll.h>
extern struct ctl_table epoll_table[]; /* for sysctl */
/* ~832 bytes of stack space used max in sys_select/sys_poll before allocating
additional memory. */
#define MAX_STACK_ALLOC 832
#define N_INLINE_POLL_ENTRIES (WQUEUES_STACK_ALLOC / sizeof(struct poll_table_entry))
struct poll_table_struct;
* structures and helpers for f_op->poll implementations
typedef void (*poll_queue_proc)(struct file *, wait_queue_head_t *, struct poll_table_struct *);
* Do not touch the structure directly, use the access functions
* poll_does_not_wait() and poll_requested_events() instead.
typedef struct poll_table_struct {
poll_queue_proc _qproc;
unsigned long _key;
} poll_table;
static inline void poll_wait(struct file * filp, wait_queue_head_t * wait_address, poll_table *p)
if (p && p->_qproc && wait_address)
p->_qproc(filp, wait_address, 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 p == NULL || p->_qproc == NULL;
* 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 unsigned long poll_requested_events(const poll_table *p)
return p ? p->_key : ~0UL;
static inline void init_poll_funcptr(poll_table *pt, poll_queue_proc qproc)
pt->_qproc = qproc;
pt->_key = ~0UL; /* all events enabled */
struct poll_table_entry {
struct file *filp;
unsigned long key;
wait_queue_entry_t wait;
wait_queue_head_t *wait_address;
* Structures and helpers for select/poll syscall
struct poll_wqueues {
poll_table pt;
struct poll_table_page *table;
struct task_struct *polling_task;
int triggered;
int error;
int inline_index;
struct poll_table_entry inline_entries[N_INLINE_POLL_ENTRIES];
extern void poll_initwait(struct poll_wqueues *pwq);
extern void poll_freewait(struct poll_wqueues *pwq);
extern int poll_schedule_timeout(struct poll_wqueues *pwq, int state,
ktime_t *expires, unsigned long slack);
extern u64 select_estimate_accuracy(struct timespec64 *tv);
#define MAX_INT64_SECONDS (((s64)(~((u64)0)>>1)/HZ)-1)
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);
#endif /* _LINUX_POLL_H */