Patch "staging: greybus: loopback: fix broken udelay" has been added to the 4.10-stable tree

This is a note to let you know that I've just added the patch titled

staging: greybus: loopback: fix broken udelay

to the 4.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
staging-greybus-loopback-fix-broken-udelay.patch
and it can be found in the queue-4.10 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Johan Hovold <[email protected]>
Date: Thu, 26 Jan 2017 12:37:32 +0100
Subject: staging: greybus: loopback: fix broken udelay

From: Johan Hovold <[email protected]>

commit 33b8807a6fe10d0e675e0704444373a6fad93188 upstream.

The loopback driver allows the user to set a minimum delay of up to one second to be inserted between test iterations (i.e. request submissions). The delay is currently specified in microseconds and is implemented using udelay.

Busy looping for long periods is not just anti-social; udelay must not be used for delays longer than a few milliseconds due to the risk of integer overflow.

Replace the broken udelay with a usleep_range with a 100 us range for short delays (< 20 ms) and otherwise revert to using msleep.

---
 drivers/staging/greybus/loopback.c |    9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

@@ -1051,8 +1051,13 @@ static int gb_loopback_fn(void *data)
 			gb_loopback_calculate_stats(gb, !!error);
 		}
 		gb->send_count++;
-		if (us_wait)
-			udelay(us_wait);
+
+		if (us_wait) {
+			if (us_wait < 20000)
+				usleep_range(us_wait, us_wait + 100);
+			else
+				msleep(us_wait / 1000);
+		}
 	}
 
 	gb_pm_runtime_put_autosuspend(bundle);

Patches currently in stable-queue which might be from [email protected] are

queue-4.10/staging-greybus-loopback-fix-broken-udelay.patch