select: add poll_select_set_timeout() and poll_select_copy_remaining() helpers
This patch adds 2 helpers that will be used for the hrtimer based select/poll:
poll_select_set_timeout() is a helper that takes a timeout (as a second, nanosecond
pair) and turns that into a "struct timespec" that represents the absolute end time.
This is a common operation in the many select() and poll() variants and needs various,
common, sanity checks.
poll_select_copy_remaining() is a helper that takes care of copying the remaining
time to userspace, as select(), pselect() and ppoll() do. This function comes in
both a natural and a compat implementation (due to datastructure differences).
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
diff --git a/include/linux/poll.h b/include/linux/poll.h
index ef45382..f65de51 100644
--- a/include/linux/poll.h
+++ b/include/linux/poll.h
@@ -120,6 +120,8 @@
extern int core_sys_select(int n, fd_set __user *inp, fd_set __user *outp,
fd_set __user *exp, s64 *timeout);
+extern int poll_select_set_timeout(struct timespec *to, long sec, long nsec);
+
#endif /* KERNEL */
#endif /* _LINUX_POLL_H */