HID: usbhid: Fix flood of "control queue full" messages

[patch description by Alan Stern]

Commit 7652dd2c5c ("USB: core: Check buffer length matches wLength
for control transfers") causes control URB submissions to fail if the
transfer_buffer_length value disagrees with the setup packet's wLength
valuel.  Unfortunately, it turns out that the usbhid can trigger this
failure mode when it submits a control request for an input report: It
pads the transfer buffer size to a multiple of the maxpacket value but
does not increase wLength correspondingly.

These failures have caused problems for people using an APS UPC, in
the form of a flood of log messages resembling:

	hid-generic 0003:051D:0002.0002: control queue full

This patch fixes the problem by setting the wLength value equal to the
padded transfer_buffer_length value in hid_submit_ctrl().  As a nice
bonus, the code which stores the transfer_buffer_length value is now
shared between the two branches of an "if" statement, so it can be
de-duplicated.

Signed-off-by: Michal Kubecek <mkubecek@suse.cz>
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Fixes: 7652dd2c5c ("USB: core: Check buffer length matches wLength for control transfers")
Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name>
Tested-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Acked-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

drivers/hid/usbhid/hid-core.c

@@ -377,27 +377,26 @@ static int hid_submit_ctrl(struct hid_device *hid)
 	len = hid_report_len(report);
 	if (dir == USB_DIR_OUT) {
 		usbhid->urbctrl->pipe = usb_sndctrlpipe(hid_to_usb_dev(hid), 0);
-		usbhid->urbctrl->transfer_buffer_length = len;
 		if (raw_report) {
 			memcpy(usbhid->ctrlbuf, raw_report, len);
 			kfree(raw_report);
 			usbhid->ctrl[usbhid->ctrltail].raw_report = NULL;
 		}
 	} else {
-		int maxpacket, padlen;
+		int maxpacket;
 
 		usbhid->urbctrl->pipe = usb_rcvctrlpipe(hid_to_usb_dev(hid), 0);
 		maxpacket = usb_maxpacket(hid_to_usb_dev(hid),
 					  usbhid->urbctrl->pipe, 0);
 		if (maxpacket > 0) {
-			padlen = DIV_ROUND_UP(len, maxpacket);
-			padlen *= maxpacket;
-			if (padlen > usbhid->bufsize)
-				padlen = usbhid->bufsize;
+			len = DIV_ROUND_UP(len, maxpacket);
+			len *= maxpacket;
+			if (len > usbhid->bufsize)
+				len = usbhid->bufsize;
 		} else
-			padlen = 0;
-		usbhid->urbctrl->transfer_buffer_length = padlen;
+			len = 0;
 	}
+	usbhid->urbctrl->transfer_buffer_length = len;
 	usbhid->urbctrl->dev = hid_to_usb_dev(hid);
 
 	usbhid->cr->bRequestType = USB_TYPE_CLASS | USB_RECIP_INTERFACE | dir;