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Subject[PATCH v2 11/26] usb: gadget: net2272: 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/net2272.c | 13 +++++++------
1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/drivers/usb/gadget/udc/net2272.c b/drivers/usb/gadget/udc/net2272.c
index 7c38057dcb4a..6a8884632273 100644
--- a/drivers/usb/gadget/udc/net2272.c
+++ b/drivers/usb/gadget/udc/net2272.c
@@ -926,7 +926,7 @@ static int
net2272_dequeue(struct usb_ep *_ep, struct usb_request *_req)
{
struct net2272_ep *ep;
- struct net2272_request *req;
+ struct net2272_request *req = NULL, *iter;
unsigned long flags;
int stopped;

@@ -939,11 +939,13 @@ net2272_dequeue(struct usb_ep *_ep, struct usb_request *_req)
ep->stopped = 1;

/* make sure it's still 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) {
ep->stopped = stopped;
spin_unlock_irqrestore(&ep->dev->lock, flags);
return -EINVAL;
@@ -954,7 +956,6 @@ net2272_dequeue(struct usb_ep *_ep, struct usb_request *_req)
dev_dbg(ep->dev->dev, "unlink (%s) pio\n", _ep->name);
net2272_done(ep, req, -ECONNRESET);
}
- req = NULL;
ep->stopped = stopped;

spin_unlock_irqrestore(&ep->dev->lock, flags);
--
2.25.1
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