[PATCH 3.16 042/254] can: kvaser_usb: Fix comparison bug in kvaser_usb_read_bulk_callback()

[Ben Hutchings]

3.16.55-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Jimmy Assarsson <jimmyassarsson@xxxxxxxxx>

commit e84f44eb5523401faeb9cc1c97895b68e3cfb78d upstream.

The conditon in the while-loop becomes true when actual_length is less than
2 (MSG_HEADER_LEN). In best case we end up with a former, already
dispatched msg, that got msg->len greater than actual_length. This will
result in a "Format error" error printout.

Problem seen when unplugging a Kvaser USB device connected to a vbox guest.

warning: comparison between signed and unsigned integer expressions
[-Wsign-compare]

Signed-off-by: Jimmy Assarsson <jimmyassarsson@xxxxxxxxx>
Signed-off-by: Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx>
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
 drivers/net/can/usb/kvaser_usb.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/net/can/usb/kvaser_usb.c
+++ b/drivers/net/can/usb/kvaser_usb.c
@@ -983,7 +983,7 @@ static void kvaser_usb_read_bulk_callbac
 		goto resubmit_urb;
 	}
 
-	while (pos <= urb->actual_length - MSG_HEADER_LEN) {
+	while (pos <= (int)(urb->actual_length - MSG_HEADER_LEN)) {
 		msg = urb->transfer_buffer + pos;
 
 		/* The Kvaser firmware can only read and write messages that