[PATCH] driver core: Use the ktime_us_delta() helper

[Zenghui Yu]

Use the ktime_us_delta() helper to measure the driver probe time. Given the
helpers already returns an s64 value, let's drop the unnecessary casting to
s64 as well. There is no functional change.

Signed-off-by: Zenghui Yu <yuzeng...@huawei.com>
---
 drivers/base/dd.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/base/dd.c b/drivers/base/dd.c
index 3cefe89e94ca..0ef5b2f32932 100644
--- a/drivers/base/dd.c
+++ b/drivers/base/dd.c
@@ -618,15 +618,14 @@ static int really_probe(struct device *dev, struct 
device_driver *drv)
  */
 static int really_probe_debug(struct device *dev, struct device_driver *drv)
 {
-       ktime_t calltime, delta, rettime;
+       ktime_t calltime, rettime;
        int ret;
 
        calltime = ktime_get();
        ret = really_probe(dev, drv);
        rettime = ktime_get();
-       delta = ktime_sub(rettime, calltime);
        pr_debug("probe of %s returned %d after %lld usecs\n",
-                dev_name(dev), ret, (s64) ktime_to_us(delta));
+                dev_name(dev), ret, ktime_us_delta(rettime, calltime));
        return ret;
 }
 
-- 
2.19.1