Re: RFR: new SiS gige driver

[Ben Greear <greearb@xxxxxxxxxxxxxxx>]

Jeff Garzik wrote:
> Andi Kleen wrote:
>
> > * netif_stop_queue in hard_start_xmit is not protected against the 
> > interrupt by the spinlock. That's racy, isn't it?
>
> Shouldn't be, if done right.  If the interrupt runs a TX completion 
> cycle, it will run the code
>     if (work_done && netif_queue_stopped(dev))
>         netif_wake_queue(dev)
> Since ->hard_start_xmit is guaranteed never to be called if the queue is 
> stopped, you also guaranteed that netif_wake_queue and ->hard_start_xmit 
> are mutually exclusive.
Is this really guaranteed?  What if the queue is stopped between the check
to see if it's stopped and the call to hard_start_xmit?

Ben


--
Ben Greear <greearb@xxxxxxxxxxxxxxx>
Candela Technologies Inc  http://www.candelatech.com