timekeeping: Make the conversion call chain consistently unsigned

Propagating a unsigned value through signed variables and functions makes
absolutely no sense and is just prone to (re)introduce subtle signed
vs. unsigned issues as happened recently.

Clean it up.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Parit Bhargava <prarit@redhat.com>
Cc: Laurent Vivier <lvivier@redhat.com>
Cc: "Christopher S. Hall" <christopher.s.hall@intel.com>
Cc: Chris Metcalf <cmetcalf@mellanox.com>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Liav Rehana <liavr@mellanox.com>
Cc: John Stultz <john.stultz@linaro.org>
Link: http://lkml.kernel.org/r/20161208204228.765843099@linutronix.deSigned-off-by: Thomas Gleixner <tglx@linutronix.de>

kernel/time/timekeeping.c

@@ -311,7 +311,7 @@ static inline u64 timekeeping_delta_to_ns(struct tk_read_base *tkr,
 	return nsec + arch_gettimeoffset();
 }
 
-static inline s64 timekeeping_get_ns(struct tk_read_base *tkr)
+static inline u64 timekeeping_get_ns(struct tk_read_base *tkr)
 {
 	cycle_t delta;
 
@@ -319,8 +319,8 @@ static inline s64 timekeeping_get_ns(struct tk_read_base *tkr)
 	return timekeeping_delta_to_ns(tkr, delta);
 }
 
-static inline s64 timekeeping_cycles_to_ns(struct tk_read_base *tkr,
-					    cycle_t cycles)
+static inline u64 timekeeping_cycles_to_ns(struct tk_read_base *tkr,
+					   cycle_t cycles)
 {
 	cycle_t delta;
 
@@ -652,7 +652,7 @@ static void timekeeping_forward_now(struct timekeeper *tk)
 {
 	struct clocksource *clock = tk->tkr_mono.clock;
 	cycle_t cycle_now, delta;
-	s64 nsec;
+	u64 nsec;
 
 	cycle_now = tk->tkr_mono.read(clock);
 	delta = clocksource_delta(cycle_now, tk->tkr_mono.cycle_last, tk->tkr_mono.mask);
@@ -681,7 +681,7 @@ int __getnstimeofday64(struct timespec64 *ts)
 {
 	struct timekeeper *tk = &tk_core.timekeeper;
 	unsigned long seq;
-	s64 nsecs = 0;
+	u64 nsecs;
 
 	do {
 		seq = read_seqcount_begin(&tk_core.seq);
@@ -721,7 +721,7 @@ ktime_t ktime_get(void)
 	struct timekeeper *tk = &tk_core.timekeeper;
 	unsigned int seq;
 	ktime_t base;
-	s64 nsecs;
+	u64 nsecs;
 
 	WARN_ON(timekeeping_suspended);
 
@@ -764,7 +764,7 @@ ktime_t ktime_get_with_offset(enum tk_offsets offs)
 	struct timekeeper *tk = &tk_core.timekeeper;
 	unsigned int seq;
 	ktime_t base, *offset = offsets[offs];
-	s64 nsecs;
+	u64 nsecs;
 
 	WARN_ON(timekeeping_suspended);
 
@@ -808,7 +808,7 @@ ktime_t ktime_get_raw(void)
 	struct timekeeper *tk = &tk_core.timekeeper;
 	unsigned int seq;
 	ktime_t base;
-	s64 nsecs;
+	u64 nsecs;
 
 	do {
 		seq = read_seqcount_begin(&tk_core.seq);
@@ -833,8 +833,8 @@ void ktime_get_ts64(struct timespec64 *ts)
 {
 	struct timekeeper *tk = &tk_core.timekeeper;
 	struct timespec64 tomono;
-	s64 nsec;
 	unsigned int seq;
+	u64 nsec;
 
 	WARN_ON(timekeeping_suspended);
 
@@ -922,8 +922,8 @@ void ktime_get_snapshot(struct system_time_snapshot *systime_snapshot)
 	unsigned long seq;
 	ktime_t base_raw;
 	ktime_t base_real;
-	s64 nsec_raw;
-	s64 nsec_real;
+	u64 nsec_raw;
+	u64 nsec_real;
 	cycle_t now;
 
 	WARN_ON_ONCE(timekeeping_suspended);
@@ -1081,7 +1081,7 @@ int get_device_system_crosststamp(int (*get_time_fn)
 	cycle_t cycles, now, interval_start;
 	unsigned int clock_was_set_seq = 0;
 	ktime_t base_real, base_raw;
-	s64 nsec_real, nsec_raw;
+	u64 nsec_real, nsec_raw;
 	u8 cs_was_changed_seq;
 	unsigned long seq;
 	bool do_interp;
@@ -1394,7 +1394,7 @@ void getrawmonotonic64(struct timespec64 *ts)
 	struct timekeeper *tk = &tk_core.timekeeper;
 	struct timespec64 ts64;
 	unsigned long seq;
-	s64 nsecs;
+	u64 nsecs;
 
 	do {
 		seq = read_seqcount_begin(&tk_core.seq);