usb: gadget: udc: max3420_udc: remove using list iterator after loop body as a ptr

If the list does not contain the expected element, the value of
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 list_for_each_entry() loop.

In preparation to limiting scope of a list iterator to the list traversal
loop, use a dedicated pointer to point to the found element [1].
Determining if an element was found is then simply checking if
the pointer is != NULL instead of using the potentially bogus pointer.

Link: https://lore.kernel.org/all/YhdfEIwI4EdtHdym@kroah.com/
Signed-off-by: Jakob Koschel <jakobkoschel@gmail.com>
Link: https://lore.kernel.org/r/20220308171818.384491-20-jakobkoschel@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/gadget/udc/max3420_udc.c b/drivers/usb/gadget/udc/max3420_udc.c
index d2a2b20..ac8a46b 100644 (file)
--- a/drivers/usb/gadget/udc/max3420_udc.c
+++ b/drivers/usb/gadget/udc/max3420_udc.c
@@ -1044,22 +1044,26 @@ static int max3420_ep_queue(struct usb_ep *_ep, struct usb_request *_req,
 
 static int max3420_ep_dequeue(struct usb_ep *_ep, struct usb_request *_req)
 {
-       struct max3420_req *t, *req = to_max3420_req(_req);
+       struct max3420_req *t = NULL;
+       struct max3420_req *req = to_max3420_req(_req);
+       struct max3420_req *iter;
        struct max3420_ep *ep = to_max3420_ep(_ep);
        unsigned long flags;
 
        spin_lock_irqsave(&ep->lock, flags);
 
        /* Pluck the descriptor from queue */
-       list_for_each_entry(t, &ep->queue, queue)
-               if (t == req) {
-                       list_del_init(&req->queue);
-                       break;
-               }
+       list_for_each_entry(iter, &ep->queue, queue) {
+               if (iter != req)
+                       continue;
+               list_del_init(&req->queue);
+               t = iter;
+               break;
+       }
 
        spin_unlock_irqrestore(&ep->lock, flags);
 
-       if (t == req)
+       if (t)
                max3420_req_done(req, -ECONNRESET);
 
        return 0;