[PATCH] sky2: Lock transmit queue while disabling device

[Mike McCormack <mikem@ring3k.org>]

netif_device_detach() does not take the tx_lock, so it's
 possible that a call to sky2_xmit_frame is still in
 progress after netif_device_detach() is complete.

Take netif_tx_lock() to make sure all transmits have
 stopped while we're disabling the devices and that
 no other CPU is still transmitting a frame after
 we've disabling the device.

Proposed fix for "sky2 panic under load" reported by Berck E. Nash.

Signed-off-by: Mike McCormack <mikem@ring3k.org>
---
 drivers/net/sky2.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/drivers/net/sky2.c b/drivers/net/sky2.c
index faa4841..8ae8520 100644
--- a/drivers/net/sky2.c
+++ b/drivers/net/sky2.c
@@ -3176,7 +3176,9 @@ static void sky2_reset(struct sky2_hw *hw)
 static void sky2_detach(struct net_device *dev)
 {
 	if (netif_running(dev)) {
+		netif_tx_lock(dev);
 		netif_device_detach(dev);	/* stop txq */
+		netif_tx_unlock(dev);
 		sky2_down(dev);
 	}
 }
-- 
1.5.6.5