fs: poll/select/recvmmsg: use timespec64 for timeout events

struct timespec is not y2038 safe.  Even though timespec might be
sufficient to represent timeouts, use struct timespec64 here as the plan
is to get rid of all timespec reference in the kernel.

The patch transitions the common functions: poll_select_set_timeout()
and select_estimate_accuracy() to use timespec64.  And, all the syscalls
that use these functions are transitioned in the same patch.

The restart block parameters for poll uses monotonic time.  Use
timespec64 here as well to assign timeout value.  This parameter in the
restart block need not change because this only holds the monotonic
timestamp at which timeout should occur.  And, unsigned long data type
should be big enough for this timestamp.

The system call interfaces will be handled in a separate series.

Compat interfaces need not change as timespec64 is an alias to struct
timespec on a 64 bit system.

Link: http://lkml.kernel.org/r/1461947989-21926-3-git-send-email-deepa.kernel@gmail.com
Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com>
Acked-by: John Stultz <john.stultz@linaro.org>
Acked-by: David S. Miller <davem@davemloft.net>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/linux/poll.h b/include/linux/poll.h
index 9fb4f40..37b057b 100644
--- a/include/linux/poll.h
+++ b/include/linux/poll.h
@@ -96,7 +96,7 @@
 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 timespec *tv);
+extern u64 select_estimate_accuracy(struct timespec64 *tv);
 
 
 static inline int poll_schedule(struct poll_wqueues *pwq, int state)
@@ -153,12 +153,13 @@
 
 #define MAX_INT64_SECONDS (((s64)(~((u64)0)>>1)/HZ)-1)
 
-extern int do_select(int n, fd_set_bits *fds, struct timespec *end_time);
+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 timespec *end_time);
+		       struct timespec64 *end_time);
 extern int core_sys_select(int n, fd_set __user *inp, fd_set __user *outp,
-			   fd_set __user *exp, struct timespec *end_time);
+			   fd_set __user *exp, struct timespec64 *end_time);
 
-extern int poll_select_set_timeout(struct timespec *to, long sec, long nsec);
+extern int poll_select_set_timeout(struct timespec64 *to, time64_t sec,
+				   long nsec);
 
 #endif /* _LINUX_POLL_H */