usb: gadget: tegra-xudc: 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/20220308171818.384491-21-jakobkoschel@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/gadget/udc/tegra-xudc.c b/drivers/usb/gadget/udc/tegra-xudc.c
index be76f89..d9c406b 100644 (file)
--- a/drivers/usb/gadget/udc/tegra-xudc.c
+++ b/drivers/usb/gadget/udc/tegra-xudc.c
@@ -1412,18 +1412,20 @@ __tegra_xudc_ep_dequeue(struct tegra_xudc_ep *ep,
                        struct tegra_xudc_request *req)
 {
        struct tegra_xudc *xudc = ep->xudc;
-       struct tegra_xudc_request *r;
+       struct tegra_xudc_request *r = NULL, *iter;
        struct tegra_xudc_trb *deq_trb;
        bool busy, kick_queue = false;
        int ret = 0;
 
        /* Make sure the request is actually queued to this endpoint. */
-       list_for_each_entry(r, &ep->queue, list) {
-               if (r == req)
-                       break;
+       list_for_each_entry(iter, &ep->queue, list) {
+               if (iter != req)
+                       continue;
+               r = iter;
+               break;
        }
 
-       if (r != req)
+       if (!r)
                return -EINVAL;
 
        /* Request hasn't been queued in the transfer ring yet. */