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Subject[PATCH v2 08/26] usb: gadget: lpc32xx_udc: remove usage of list iterator past the loop body
Date
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@kroah.com/
Signed-off-by: Jakob Koschel <jakobkoschel@gmail.com>
---
drivers/usb/gadget/udc/lpc32xx_udc.c | 12 +++++++-----
1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/drivers/usb/gadget/udc/lpc32xx_udc.c b/drivers/usb/gadget/udc/lpc32xx_udc.c
index a25d01c89564..6117ae8e7242 100644
--- a/drivers/usb/gadget/udc/lpc32xx_udc.c
+++ b/drivers/usb/gadget/udc/lpc32xx_udc.c
@@ -1830,7 +1830,7 @@ static int lpc32xx_ep_queue(struct usb_ep *_ep,
static int lpc32xx_ep_dequeue(struct usb_ep *_ep, struct usb_request *_req)
{
struct lpc32xx_ep *ep;
- struct lpc32xx_request *req;
+ struct lpc32xx_request *req = NULL, *iter;
unsigned long flags;

ep = container_of(_ep, struct lpc32xx_ep, ep);
@@ -1840,11 +1840,13 @@ static int lpc32xx_ep_dequeue(struct usb_ep *_ep, struct usb_request *_req)
spin_lock_irqsave(&ep->udc->lock, flags);

/* make sure it's actually queued on this endpoint */
- list_for_each_entry(req, &ep->queue, queue) {
- if (&req->req == _req)
- break;
+ list_for_each_entry(iter, &ep->queue, queue) {
+ if (&iter->req != _req)
+ continue;
+ req = iter;
+ break;
}
- if (&req->req != _req) {
+ if (!req) {
spin_unlock_irqrestore(&ep->udc->lock, flags);
return -EINVAL;
}
--
2.25.1
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