Re: e1000_netpoll(): disable_irq() triggers might_sleep() on linux-next

Bart Van Assche
2015-01-05T10:07:06Z

On 12/02/14 17:35, Sabrina Dubroca wrote:
> @@ -3751,10 +3753,8 @@ void e1000_update_stats(struct e1000_adapter *adapter)
> * @irq: interrupt number
> * @data: pointer to a network interface device structure
> **/
> -static irqreturn_t e1000_intr(int irq, void *data)
> +static irqreturn_t __e1000_intr(int irq, struct e1000_adapter *adapter)
> {
> - struct net_device *netdev = data;
> - struct e1000_adapter *adapter = netdev_priv(netdev);
> struct e1000_hw *hw = &adapter->hw;
> u32 icr = er32(ICR);
>
> @@ -3796,6 +3796,19 @@ static irqreturn_t e1000_intr(int irq, void *data)
> return IRQ_HANDLED;
> }
>
> +static irqreturn_t e1000_intr(int irq, void *data)
> +{
> + struct net_device *netdev = data;
> + struct e1000_adapter *adapter = netdev_priv(netdev);
> + irqreturn_t ret;
> +
> + netpoll_irq_lock(&adapter->netpoll_lock);
> + ret = __e1000_intr(irq, adapter);
> + netpoll_irq_unlock(&adapter->netpoll_lock);
> +
> + return ret;
> +}
> +
> /**
> * e1000_clean - NAPI Rx polling callback
> * @adapter: board private structure
> @@ -5220,9 +5233,7 @@ static void e1000_netpoll(struct net_device *netdev)
> {
> struct e1000_adapter *adapter = netdev_priv(netdev);
>
> - disable_irq(adapter->pdev->irq);
> e1000_intr(adapter->pdev->irq, netdev);
> - enable_irq(adapter->pdev->irq);
> }
> #endif

Sorry but this patch looks incorrect to me. Since e1000_netpoll() can be
called with interrupts disabled e1000_intr() must not enable interrupts
unconditionally. Shouldn't the save / restore variants be used in
e1000_intr() instead of spin_lock_irq() and spin_unlock_irq() ? See also
the invocation of call_console_drivers() in console_unlock().

Bart.