usb: cdns3: change place of 'priv_ep' assignment in cdns3_gadget_ep_dequeue(),...

usb: cdns3: change place of 'priv_ep' assignment in cdns3_gadget_ep_dequeue(), cdns3_gadget_ep_enable()

If 'ep' is NULL, result of ep_to_cdns3_ep(ep) is invalid pointer
and its dereference with priv_ep->cdns3_dev may cause panic.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Fixes: 7733f6c3 ("usb: cdns3: Add Cadence USB3 DRD Driver")
Acked-by: Peter Chen <peter.chen@kernel.org>
Signed-off-by: Andrey Strachuk <strochuk@ispras.ru>
Link: https://lore.kernel.org/r/20220718160052.4188-1-strochuk@ispras.ruSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/cdns3/cdns3-gadget.c

@@ -2285,14 +2285,15 @@ static int cdns3_gadget_ep_enable(struct usb_ep *ep,
 	int val;
 
 	priv_ep = ep_to_cdns3_ep(ep);
-	priv_dev = priv_ep->cdns3_dev;
-	comp_desc = priv_ep->endpoint.comp_desc;
 
 	if (!ep || !desc || desc->bDescriptorType != USB_DT_ENDPOINT) {
 		dev_dbg(priv_dev->dev, "usbss: invalid parameters\n");
 		return -EINVAL;
 	}
 
+	comp_desc = priv_ep->endpoint.comp_desc;
+	priv_dev = priv_ep->cdns3_dev;
+
 	if (!desc->wMaxPacketSize) {
 		dev_err(priv_dev->dev, "usbss: missing wMaxPacketSize\n");
 		return -EINVAL;
@@ -2600,7 +2601,7 @@ int cdns3_gadget_ep_dequeue(struct usb_ep *ep,
 			    struct usb_request *request)
 {
 	struct cdns3_endpoint *priv_ep = ep_to_cdns3_ep(ep);
-	struct cdns3_device *priv_dev = priv_ep->cdns3_dev;
+	struct cdns3_device *priv_dev;
 	struct usb_request *req, *req_temp;
 	struct cdns3_request *priv_req;
 	struct cdns3_trb *link_trb;
@@ -2611,6 +2612,8 @@ int cdns3_gadget_ep_dequeue(struct usb_ep *ep,
 	if (!ep || !request || !ep->desc)
 		return -EINVAL;
 
+	priv_dev = priv_ep->cdns3_dev;
+
 	spin_lock_irqsave(&priv_dev->lock, flags);
 
 	priv_req = to_cdns3_request(request);