[PATCH v2 20/26] usb: gadget: tegra-xudc: remove using list iterator after loop body as a ptr

[Jakob Koschel]

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@xxxxxxxxx/
Signed-off-by: Jakob Koschel <jakobkoschel@xxxxxxxxx>
---
 drivers/usb/gadget/udc/tegra-xudc.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/drivers/usb/gadget/udc/tegra-xudc.c b/drivers/usb/gadget/udc/tegra-xudc.c
index 43f1b0d461c1..1ad616d81c96 100644
--- a/drivers/usb/gadget/udc/tegra-xudc.c
+++ b/drivers/usb/gadget/udc/tegra-xudc.c
@@ -1413,18 +1413,20 @@ __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. */
-- 
2.25.1