usb: gadget: goku_udc: 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/20220308171818.384491-7-jakobkoschel@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/gadget/udc/goku_udc.c b/drivers/usb/gadget/udc/goku_udc.c
index 3757a77..bdc56b2 100644 (file)
--- a/drivers/usb/gadget/udc/goku_udc.c
+++ b/drivers/usb/gadget/udc/goku_udc.c
@@ -809,7 +809,7 @@ static void nuke(struct goku_ep *ep, int status)
 /* dequeue JUST ONE request */
 static int goku_dequeue(struct usb_ep *_ep, struct usb_request *_req)
 {
-       struct goku_request     *req;
+       struct goku_request     *req = NULL, *iter;
        struct goku_ep          *ep;
        struct goku_udc         *dev;
        unsigned long           flags;
@@ -833,11 +833,13 @@ static int goku_dequeue(struct usb_ep *_ep, struct usb_request *_req)
        spin_lock_irqsave(&dev->lock, flags);
 
        /* make sure it's actually queued on this endpoint */
-       list_for_each_entry (req, &ep->queue, queue) {
-               if (&req->req == _req)
-                       break;
+       list_for_each_entry(iter, &ep->queue, queue) {
+               if (&iter->req != _req)
+                       continue;
+               req = iter;
+               break;
        }
-       if (&req->req != _req) {
+       if (!req) {
                spin_unlock_irqrestore (&dev->lock, flags);
                return -EINVAL;
        }