usb: gadget: udc: at91: 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/20220308171818.384491-6-jakobkoschel@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/gadget/udc/at91_udc.c b/drivers/usb/gadget/udc/at91_udc.c
index 9040a05..7289872 100644 (file)
--- a/drivers/usb/gadget/udc/at91_udc.c
+++ b/drivers/usb/gadget/udc/at91_udc.c
@@ -704,7 +704,7 @@ done:
 static int at91_ep_dequeue(struct usb_ep *_ep, struct usb_request *_req)
 {
        struct at91_ep          *ep;
-       struct at91_request     *req;
+       struct at91_request     *req = NULL, *iter;
        unsigned long           flags;
        struct at91_udc         *udc;
 
@@ -717,11 +717,13 @@ static int at91_ep_dequeue(struct usb_ep *_ep, struct usb_request *_req)
        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->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(&udc->lock, flags);
                return -EINVAL;
        }