usb: gadget: bdc: 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/20220308171818.384491-3-jakobkoschel@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/gadget/udc/bdc/bdc_ep.c b/drivers/usb/gadget/udc/bdc/bdc_ep.c
index 8e2f20b..fa88f21 100644 (file)
--- a/drivers/usb/gadget/udc/bdc/bdc_ep.c
+++ b/drivers/usb/gadget/udc/bdc/bdc_ep.c
@@ -1757,6 +1757,7 @@ static int bdc_gadget_ep_dequeue(struct usb_ep *_ep,
                                  struct usb_request *_req)
 {
        struct bdc_req *req;
+       struct bdc_req *iter;
        unsigned long flags;
        struct bdc_ep *ep;
        struct bdc *bdc;
@@ -1771,12 +1772,16 @@ static int bdc_gadget_ep_dequeue(struct usb_ep *_ep,
        dev_dbg(bdc->dev, "%s ep:%s req:%p\n", __func__, ep->name, req);
        bdc_dbg_bd_list(bdc, ep);
        spin_lock_irqsave(&bdc->lock, flags);
+
+       req = NULL;
        /* make sure it's still 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(&bdc->lock, flags);
                dev_err(bdc->dev, "usb_req !=req n");
                return -EINVAL;