[PATCH 12/26] usb: gadget: udc: net2280: remove usage of list iterator past the loop body

From: Jakob Koschel
Date: Sun Mar 06 2022 - 12:51:53 EST


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@xxxxxxxxx/
Signed-off-by: Jakob Koschel <jakobkoschel@xxxxxxxxx>
---
drivers/usb/gadget/udc/net2280.c | 11 +++++++----
1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/drivers/usb/gadget/udc/net2280.c b/drivers/usb/gadget/udc/net2280.c
index 16e7d2db6411..dbf5592dbcf0 100644
--- a/drivers/usb/gadget/udc/net2280.c
+++ b/drivers/usb/gadget/udc/net2280.c
@@ -1240,7 +1240,8 @@ static void nuke(struct net2280_ep *ep)
static int net2280_dequeue(struct usb_ep *_ep, struct usb_request *_req)
{
struct net2280_ep *ep;
- struct net2280_request *req;
+ struct net2280_request *req = NULL;
+ struct net2280_request *tmp;
unsigned long flags;
u32 dmactl;
int stopped;
@@ -1266,11 +1267,13 @@ static int net2280_dequeue(struct usb_ep *_ep, struct usb_request *_req)
}

/* make sure it's still queued on this endpoint */
- list_for_each_entry(req, &ep->queue, queue) {
- if (&req->req == _req)
+ list_for_each_entry(tmp, &ep->queue, queue) {
+ if (&tmp->req == _req) {
+ req = tmp;
break;
+ }
}
- if (&req->req != _req) {
+ if (!req) {
ep->stopped = stopped;
spin_unlock_irqrestore(&ep->dev->lock, flags);
ep_dbg(ep->dev, "%s: Request mismatch\n", __func__);
--
2.25.1