usbip: use monotonic timestamps

This gets rid of the deprecated do_gettimeofday() function in usbip.
The comment above vgadget_get_frame() mentions that it suffers
from issues with the time jumps due to suspend and settimeofday,
so I'm changing it to use ktime_get_ts64() to use monotonic times
that don't have this problem.

I couldn't tell whether we should use CLOCK_MONOTONIC or
CLOCK_MONOTONIC_RAW here, the difference being the exact rate
when correcting for NTP. I picked monotonic time since it doesn't
change the speed to the existing code and should be better
synchronized with other machines we talk to.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Krzysztof Opasiak <k.opasiak@samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/usbip/vudc.h

@@ -105,7 +105,7 @@ struct vudc {
 
 	struct usbip_device ud;
 	struct transfer_timer tr_timer;
-	struct timeval start_time;
+	struct timespec64 start_time;
 
 	struct list_head urb_queue;
 

drivers/usb/usbip/vudc_dev.c

@@ -136,15 +136,14 @@ struct vep *vudc_find_endpoint(struct vudc *udc, u8 address)
 
 /* gadget ops */
 
-/* FIXME - this will probably misbehave when suspend/resume is added */
 static int vgadget_get_frame(struct usb_gadget *_gadget)
 {
-	struct timeval now;
+	struct timespec64 now;
 	struct vudc *udc = usb_gadget_to_vudc(_gadget);
 
-	do_gettimeofday(&now);
+	ktime_get_ts64(&now);
 	return ((now.tv_sec - udc->start_time.tv_sec) * 1000 +
-			(now.tv_usec - udc->start_time.tv_usec) / 1000)
+		(now.tv_nsec - udc->start_time.tv_nsec) / NSEC_PER_MSEC)
 			& 0x7FF;
 }
 

drivers/usb/usbip/vudc_sysfs.c

@@ -162,7 +162,7 @@ static ssize_t store_sockfd(struct device *dev, struct device_attribute *attr,
 		udc->ud.status = SDEV_ST_USED;
 		spin_unlock_irq(&udc->ud.lock);
 
-		do_gettimeofday(&udc->start_time);
+		ktime_get_ts64(&udc->start_time);
 		v_start_timer(udc);
 		udc->connected = 1;
 	} else {