PM: Use 64-bit timekeeping

The freezer try_to_freeze_tasks uses 'struct timeval' for start and end times, tracking time taken to freeze tasks. 'struct timeval' on 32-bit systems will have its tv_sec overflow in year 2038 and beyond. This patches uses 'ktime_t' (which has 64 bit values for seconds) for start and end time.

Suggested-by Arnd Bergmann <[email protected]>

Signed-off-by Tina Ruchandani <[email protected]>

---
Changes in v2:
- Use ktime_t to be able to use ktime_ms_delta which is more efficient than timespec64 based methods.

---
 kernel/power/process.c | 12 +++++-------
 1 file changed, 5 insertions(+), 7 deletions(-)

kernel/power/process.c +0 -0

index 5a6ec86..52414dd 100644

kernel/power/process.c +4 -7

 /* 

@@ -30,13 +31,12 @@ static int try_to_freeze_tasks(bool user_only)
 	unsigned long end_time;
 	unsigned int todo;
 	bool wq_busy = false;
-	struct timeval start, end;
-	u64 elapsed_msecs64;
+	ktime_t start, end;
 	unsigned int elapsed_msecs;
 	bool wakeup = false;
 	int sleep_usecs = USEC_PER_MSEC;
 
-	do_gettimeofday(&start);
+	start = ktime_get();
 
 	end_time = jiffies + msecs_to_jiffies(freeze_timeout_msecs);
 

@@ -78,10 +78,8 @@ static int try_to_freeze_tasks(bool user_only)
 			sleep_usecs *= 2;
 	}
 
-	do_gettimeofday(&end);
-	elapsed_msecs64 = timeval_to_ns(&end) - timeval_to_ns(&start);
-	do_div(elapsed_msecs64, NSEC_PER_MSEC);
-	elapsed_msecs = elapsed_msecs64;
+	end = ktime_get();
+	elapsed_msecs = (unsigned int) ktime_ms_delta(end, start);
 
 	if (todo) {
 		printk("\n");