On Mon, 28 Jan 2013, Anton Tikhomirov wrote:
> Hello,
>
> In drivers/usb/core/hcd.c: usb_hcd_flush_endpoint() uses
> list_for_each_entry() to unlink URBs pending on
> endpoint. At the same time unlink1() calls usb_rh_urb_dequeue()
> where URB is removed from its endpoint queue:
>
> void usb_hcd_unlink_urb_from_ep(struct usb_hcd *hcd, struct urb *urb)
> {
> /* clear all state linking urb to this dev (and hcd) */
> spin_lock(&hcd_urb_list_lock);
> list_del_init(&urb->urb_list);
> spin_unlock(&hcd_urb_list_lock);
> }
>
> Shall we use safe version of list_for_each_entry() for cancelling URBs?
No. Read usb_hcd_flush_endpoint() more closely. After calling
unlink1() it restarts the loop from the beginning.
Alan Stern
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