2022-03-07 03:36:20

by Jakob Koschel

[permalink] [raw]
Subject: [PATCH 06/26] usb: gadget: goku_udc: remove usage of list iterator past the loop body

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/[email protected]/
Signed-off-by: Jakob Koschel <[email protected]>
---
drivers/usb/gadget/udc/goku_udc.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/usb/gadget/udc/goku_udc.c b/drivers/usb/gadget/udc/goku_udc.c
index 3757a772a55e..62153e964655 100644
--- a/drivers/usb/gadget/udc/goku_udc.c
+++ b/drivers/usb/gadget/udc/goku_udc.c
@@ -809,7 +809,7 @@ static void nuke(struct goku_ep *ep, int status)
/* dequeue JUST ONE request */
static int goku_dequeue(struct usb_ep *_ep, struct usb_request *_req)
{
- struct goku_request *req;
+ struct goku_request *req = NULL, *tmp;
struct goku_ep *ep;
struct goku_udc *dev;
unsigned long flags;
@@ -833,11 +833,13 @@ static int goku_dequeue(struct usb_ep *_ep, struct usb_request *_req)
spin_lock_irqsave(&dev->lock, flags);

/* make sure it's actually 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) {
spin_unlock_irqrestore (&dev->lock, flags);
return -EINVAL;
}
--
2.25.1