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    Subject[PATCH v2 14/26] usb: gadget: s3c-hsudc: 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/s3c-hsudc.c | 12 +++++++-----
    1 file changed, 7 insertions(+), 5 deletions(-)

    diff --git a/drivers/usb/gadget/udc/s3c-hsudc.c b/drivers/usb/gadget/udc/s3c-hsudc.c
    index 89f1f8c9f02e..bf803e013458 100644
    --- a/drivers/usb/gadget/udc/s3c-hsudc.c
    +++ b/drivers/usb/gadget/udc/s3c-hsudc.c
    @@ -877,7 +877,7 @@ static int s3c_hsudc_dequeue(struct usb_ep *_ep, struct usb_request *_req)
    {
    struct s3c_hsudc_ep *hsep = our_ep(_ep);
    struct s3c_hsudc *hsudc = hsep->dev;
    - struct s3c_hsudc_req *hsreq;
    + struct s3c_hsudc_req *hsreq = NULL, *iter;
    unsigned long flags;

    hsep = our_ep(_ep);
    @@ -886,11 +886,13 @@ static int s3c_hsudc_dequeue(struct usb_ep *_ep, struct usb_request *_req)

    spin_lock_irqsave(&hsudc->lock, flags);

    - list_for_each_entry(hsreq, &hsep->queue, queue) {
    - if (&hsreq->req == _req)
    - break;
    + list_for_each_entry(iter, &hsep->queue, queue) {
    + if (&iter->req != _req)
    + continue;
    + hsreq = iter;
    + break;
    }
    - if (&hsreq->req != _req) {
    + if (!hsreq) {
    spin_unlock_irqrestore(&hsudc->lock, flags);
    return -EINVAL;
    }
    --
    2.25.1
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