Hello, Alan, Petr.
On Wed, Sep 17, 2014 at 01:36:26PM -0400, Alan Stern wrote:
> > - /* If khubd ever becomes multithreaded, this will need a lock */
> > + /* If hub_wq ever becomes multithreaded, this will need a lock */
> > if (udev->wusb) {
> > devnum = udev->portnum + 1;
> > BUG_ON(test_bit(devnum, bus->devmap.devicemap));
>
> You probably didn't notice when changing this comment. But in fact,
> workqueues _are_ multithreaded. Therefore you need to add a lock to
> this routine.
Haven't read the code but if this function is called from a single
work_struct, workqueue guarantees that there's only single thread of
execution at any given time. A work item is never executed
concurrently no matter what.
Thanks.
--
tejun
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