usb: gadget: udc-xilinx: remove usage of list iterator past the loop body

If the list representing the request queue does not contain the expected
request, the value of the list_for_each_entry() iterator will not point
to a valid structure. To avoid type confusion in such case, the list
iterator scope will be limited to the list_for_each_entry() loop.

In preparation to limiting scope of the list iterator to the list traversal
loop, use a dedicated pointer to point to the found request object [1].

Link: https://lore.kernel.org/all/YhdfEIwI4EdtHdym@kroah.com/
Signed-off-by: Jakob Koschel <jakobkoschel@gmail.com>
Link: https://lore.kernel.org/r/20220308171818.384491-16-jakobkoschel@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/gadget/udc/udc-xilinx.c b/drivers/usb/gadget/udc/udc-xilinx.c
index 2907fad..428c755 100644 (file)
--- a/drivers/usb/gadget/udc/udc-xilinx.c
+++ b/drivers/usb/gadget/udc/udc-xilinx.c
@@ -1136,17 +1136,20 @@ static int xudc_ep_queue(struct usb_ep *_ep, struct usb_request *_req,
 static int xudc_ep_dequeue(struct usb_ep *_ep, struct usb_request *_req)
 {
        struct xusb_ep *ep      = to_xusb_ep(_ep);
-       struct xusb_req *req    = to_xusb_req(_req);
+       struct xusb_req *req    = NULL;
+       struct xusb_req *iter;
        struct xusb_udc *udc    = ep->udc;
        unsigned long flags;
 
        spin_lock_irqsave(&udc->lock, flags);
        /* Make sure it's actually queued on this endpoint */
-       list_for_each_entry(req, &ep->queue, queue) {
-               if (&req->usb_req == _req)
-                       break;
+       list_for_each_entry(iter, &ep->queue, queue) {
+               if (&iter->usb_req != _req)
+                       continue;
+               req = iter;
+               break;
        }
-       if (&req->usb_req != _req) {
+       if (!req) {
                spin_unlock_irqrestore(&udc->lock, flags);
                return -EINVAL;
        }