USB: usbtest: use URB_ZERO_PACKET for BULK-OUT transfers

Executing
| testusb -a -c 1 -t 3 -v 421 -s 2048

does not complete on the gadget side.
g_zero enqueues a 4096 bytes long buffer. The host sends 2048bytes which
is a multiple of wMaxPacketSize (either 64 or 512 bytes). The host is
done with sending data but the gadget waits for more.
Since the protocol does not include transfer-length-field sending a
terminating zero packet seems the only way out.

Reviewed-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 3 insertions, 1 deletions

diff --git a/drivers/usb/misc/usbtest.c b/drivers/usb/misc/usbtest.c
index bb10846affc3..bd715006b056 100644
--- a/drivers/usb/misc/usbtest.c
+++ b/drivers/usb/misc/usbtest.c
@@ -359,8 +359,10 @@ static int simple_io(
         urb->context = &completion;
         while (retval == 0 && iterations-- > 0) {
                 init_completion(&completion);
-                if (usb_pipeout(urb->pipe))
+                if (usb_pipeout(urb->pipe)) {
                         simple_fill_buf(urb);
+                        urb->transfer_flags |= URB_ZERO_PACKET;
+                }
                 retval = usb_submit_urb(urb, GFP_KERNEL);
                 if (retval != 0)
                         break;