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Subject[PATCH 19/26] usb: gadget: udc: max3420_udc: remove using list iterator after loop body as a ptr
Date
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>
---
drivers/usb/gadget/udc/max3420_udc.c | 11 +++++++----
1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/drivers/usb/gadget/udc/max3420_udc.c b/drivers/usb/gadget/udc/max3420_udc.c
index d2a2b20cc1ad..d1b010b5f4a0 100644
--- a/drivers/usb/gadget/udc/max3420_udc.c
+++ b/drivers/usb/gadget/udc/max3420_udc.c
@@ -1044,22 +1044,25 @@ static int max3420_ep_queue(struct usb_ep *_ep, struct usb_request *_req,

static int max3420_ep_dequeue(struct usb_ep *_ep, struct usb_request *_req)
{
- struct max3420_req *t, *req = to_max3420_req(_req);
+ struct max3420_req *t = NULL;
+ struct max3420_req *req = to_max3420_req(_req);
+ struct max3420_req *tmp;
struct max3420_ep *ep = to_max3420_ep(_ep);
unsigned long flags;

spin_lock_irqsave(&ep->lock, flags);

/* Pluck the descriptor from queue */
- list_for_each_entry(t, &ep->queue, queue)
- if (t == req) {
+ list_for_each_entry(tmp, &ep->queue, queue)
+ if (tmp == req) {
list_del_init(&req->queue);
+ t = tmp;
break;
}

spin_unlock_irqrestore(&ep->lock, flags);

- if (t == req)
+ if (t)
max3420_req_done(req, -ECONNRESET);

return 0;
--
2.25.1
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