epoll: make epoll_wait() use the hrtimer range feature

This make epoll use hrtimers for the timeout value which prevents
epoll_wait() from timing out up to a millisecond early.

This mirrors the behavior of select() and poll().

Signed-off-by: Shawn Bohrer <shawn.bohrer@gmail.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Acked-by: Davide Libenzi <davidel@xmailserver.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 2 insertions, 0 deletions

diff --git a/include/linux/poll.h b/include/linux/poll.h
index 600cc1fde64d..56e76af78102 100644
--- a/include/linux/poll.h
+++ b/include/linux/poll.h
@@ -73,6 +73,8 @@ 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 long select_estimate_accuracy(struct timespec *tv);
+
 
 static inline int poll_schedule(struct poll_wqueues *pwq, int state)
 {