drivers/net: use tasklet_kill in device remove/close process

Some driver uses tasklet_disable in device remove/close process,
tasklet_disable will inc tasklet->count and return. If the tasklet
is not handled yet because some softirq pressure, the tasklet will
placed on the tasklet_vec, never have a chance to excute. This might
lead to ksoftirqd heavy loaded, wakeup with pending_softirq, but
tasklet is disabled. tasklet_kill should be used in this case.

Signed-off-by: Xiaotian Feng <dannyfeng@tencent.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: netdev@vger.kernel.org
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/micrel/ksz884x.c

@@ -5407,8 +5407,8 @@ static int netdev_close(struct net_device *dev)
 		/* Delay for receive task to stop scheduling itself. */
 		msleep(2000 / HZ);
 
-		tasklet_disable(&hw_priv->rx_tasklet);
-		tasklet_disable(&hw_priv->tx_tasklet);
+		tasklet_kill(&hw_priv->rx_tasklet);
+		tasklet_kill(&hw_priv->tx_tasklet);
 		free_irq(dev->irq, hw_priv->dev);
 
 		transmit_cleanup(hw_priv, 0);