• David S. Miller's avatar
    [NET]: Fix interrupt semaphore corruption in Intel drivers. · 49d85c50
    David S. Miller authored
    Several of the Intel ethernet drivers keep an atomic counter used to
    manage when to actually hit the hardware with a disable or an enable.
    
    The way the net_rx_work() breakout logic works during a pending
    napi_disable() is that it simply unschedules the poll even if it
    still has work.
    
    This can potentially leave interrupts disabled, but that is OK
    because all of the drivers are about to disable interrupts
    anyways in all such code paths that do a napi_disable().
    
    Unfortunately, this trips up the semaphore used here in the Intel
    drivers.  If you hit this case, when you try to bring the interface
    back up it won't enable interrupts.  A reload of the driver module
    fixes it of course.
    
    So what we do is make sure all the sequences now go:
    
    	napi_disable();
    	atomic_set(&adapter->irq_sem, 0);
    	*_irq_disable();
    
    which makes sure the counter is always in the correct state.
    
    Reported by Robert Olsson.
    Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
    49d85c50
netdev.c 114 KB