drivers/net: fixed drivers that support netpoll use ndo_start_xmit()

The NETPOLL API requires that interrupts remain disabled in
netpoll_send_skb(). The use of "A functions set" in the NETPOLL API
callbacks causes the interrupts to get enabled and can lead to kernel
instability.

The solution is to use "B functions set" to prevent the irqs from
getting enabled while in netpoll_send_skb().

A functions set:
local_irq_disable()/local_irq_enable()
spin_lock_irq()/spin_unlock_irq()
spin_trylock_irq()/spin_unlock_irq()

B functions set:
local_irq_save()/local_irq_restore()
spin_lock_irqsave()/spin_unlock_irqrestore()
spin_trylock_irqsave()/spin_unlock_irqrestore()

Signed-off-by: Dongdong Deng <dongdong.deng@windriver.com>
Acked-by: Matt Mackall <mpm@selenic.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 3 insertions, 2 deletions

diff --git a/drivers/net/ixp2000/ixpdev.c b/drivers/net/ixp2000/ixpdev.c
index 2a0174b62e96..92fb8235c766 100644
--- a/drivers/net/ixp2000/ixpdev.c
+++ b/drivers/net/ixp2000/ixpdev.c
@@ -41,6 +41,7 @@ static int ixpdev_xmit(struct sk_buff *skb, struct net_device *dev)
         struct ixpdev_priv *ip = netdev_priv(dev);
         struct ixpdev_tx_desc *desc;
         int entry;
+        unsigned long flags;
 
         if (unlikely(skb->len > PAGE_SIZE)) {
                 /* @@@ Count drops.  */
@@ -63,11 +64,11 @@ static int ixpdev_xmit(struct sk_buff *skb, struct net_device *dev)
 
         dev->trans_start = jiffies;
 
-        local_irq_disable();
+        local_irq_save(flags);
         ip->tx_queue_entries++;
         if (ip->tx_queue_entries == TX_BUF_COUNT_PER_CHAN)
                 netif_stop_queue(dev);
-        local_irq_enable();
+        local_irq_restore(flags);
 
         return 0;
 }