usb: gadget: aspeed: 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/20220308171818.384491-17-jakobkoschel@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/gadget/udc/aspeed-vhub/epn.c b/drivers/usb/gadget/udc/aspeed-vhub/epn.c
index 917892c..b525288 100644 (file)
--- a/drivers/usb/gadget/udc/aspeed-vhub/epn.c
+++ b/drivers/usb/gadget/udc/aspeed-vhub/epn.c
@@ -466,19 +466,21 @@ static int ast_vhub_epn_dequeue(struct usb_ep* u_ep, struct usb_request *u_req)
 {
        struct ast_vhub_ep *ep = to_ast_ep(u_ep);
        struct ast_vhub *vhub = ep->vhub;
-       struct ast_vhub_req *req;
+       struct ast_vhub_req *req = NULL, *iter;
        unsigned long flags;
        int rc = -EINVAL;
 
        spin_lock_irqsave(&vhub->lock, flags);
 
        /* Make sure it's actually queued on this endpoint */
-       list_for_each_entry (req, &ep->queue, queue) {
-               if (&req->req == u_req)
-                       break;
+       list_for_each_entry(iter, &ep->queue, queue) {
+               if (&iter->req != u_req)
+                       continue;
+               req = iter;
+               break;
        }
 
-       if (&req->req == u_req) {
+       if (req) {
                EPVDBG(ep, "dequeue req @%p active=%d\n",
                       req, req->active);
                if (req->active)