blob: 37b057b63b465afa0edf3e372cb561d7670a3089 [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 <asm/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_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);
static inline int poll_schedule(struct poll_wqueues *pwq, int state)
return poll_schedule_timeout(pwq, state, NULL, 0);
* Scalable version of the fd_set.
typedef struct {
unsigned long *in, *out, *ex;
unsigned long *res_in, *res_out, *res_ex;
} fd_set_bits;
* How many longwords for "nr" bits?
#define FDS_BITPERLONG (8*sizeof(long))
#define FDS_BYTES(nr) (FDS_LONGS(nr)*sizeof(long))
* We do a VERIFY_WRITE here even though we are only reading this time:
* we'll write to it eventually..
* Use "unsigned long" accesses to let user-mode fd_set's be long-aligned.
static inline
int get_fd_set(unsigned long nr, void __user *ufdset, unsigned long *fdset)
nr = FDS_BYTES(nr);
if (ufdset)
return copy_from_user(fdset, ufdset, nr) ? -EFAULT : 0;
memset(fdset, 0, nr);
return 0;
static inline unsigned long __must_check
set_fd_set(unsigned long nr, void __user *ufdset, unsigned long *fdset)
if (ufdset)
return __copy_to_user(ufdset, fdset, FDS_BYTES(nr));
return 0;
static inline
void zero_fd_set(unsigned long nr, unsigned long *fdset)
memset(fdset, 0, FDS_BYTES(nr));
#define MAX_INT64_SECONDS (((s64)(~((u64)0)>>1)/HZ)-1)
extern int do_select(int n, fd_set_bits *fds, struct timespec64 *end_time);
extern int do_sys_poll(struct pollfd __user * ufds, unsigned int nfds,
struct timespec64 *end_time);
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 */