drivers/net: using spin_lock_irqsave() in net_send_packet()

spin_unlock_irq() will enable interrupt in net_send_packet(),
this patch changes it to spin_lock_irqsave/spin_lock_irqrestore,
so that it doesn't enable interrupts when already disabled,
and netconsole would work properly over cs89x0/isa-skeleton.

Call trace:
netconsole write_msg()
{
 ...
 -> spin_lock_irqsave();
        -> netpoll_send_udp()
          -> netpoll_send_skb()
            -> net_send_packet()
              ->...

 -> spin_unlock_irqrestore();
 ...
}

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

1 files changed, 3 insertions, 2 deletions

diff --git a/drivers/net/isa-skeleton.c b/drivers/net/isa-skeleton.c
index 73585fd8f29f..d12377b84358 100644
--- a/drivers/net/isa-skeleton.c
+++ b/drivers/net/isa-skeleton.c
@@ -430,7 +430,8 @@ static int net_send_packet(struct sk_buff *skb, struct net_device *dev)
          * hardware interrupt handler.  Queue flow control is
          * thus managed under this lock as well.
          */
-        spin_lock_irq(&np->lock);
+        unsigned long flags;
+        spin_lock_irqsave(&np->lock, flags);
 
         add_to_tx_ring(np, skb, length);
         dev->trans_start = jiffies;
@@ -446,7 +447,7 @@ static int net_send_packet(struct sk_buff *skb, struct net_device *dev)
          * is when the transmit statistics are updated.
          */
 
-        spin_unlock_irq(&np->lock);
+        spin_unlock_irqrestore(&np->lock, flags);
 #else
         /* This is the case for older hardware which takes
          * a single transmit buffer at a time, and it is