[PATCH] usb: cdns2: fix memory double free in cdns2_gadget_giveback

[ReBeating <rebeating@163.com>]

A patch similar to commit 5fd9e45f1ebc("usb: cdns3: fix memory double
 free when handle zero packet").

As 5fd9e45f1ebc points out, the cdns2_gadget_giveback() function also has
the same memory double free issue when handling zero-length packets.

Add check for usb_gadget_giveback_request() to avoid double free of memory.
If it's additional zero length packet request, do not call 
usb_gadget_giveback_request().

Signed-off-by: ReBeating <rebeating@163.com>
---
 drivers/usb/gadget/udc/cdns2/cdns2-gadget.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/usb/gadget/udc/cdns2/cdns2-gadget.c b/drivers/usb/gadget/udc/cdns2/cdns2-gadget.c
index 7e69944ef18a..4f7898c2e364 100644
--- a/drivers/usb/gadget/udc/cdns2/cdns2-gadget.c
+++ b/drivers/usb/gadget/udc/cdns2/cdns2-gadget.c
@@ -253,7 +253,7 @@ void cdns2_gadget_giveback(struct cdns2_endpoint *pep,
 
 	trace_cdns2_request_giveback(preq);
 
-	if (request->complete) {
+	if (request->complete && request->buf != pdev->zlp_buf) {
 		spin_unlock(&pdev->lock);
 		usb_gadget_giveback_request(&pep->endpoint, request);
 		spin_lock(&pdev->lock);
-- 
2.34.1