tree 31bb2d5574adc10d342a01b2081c9907e917c554
parent 2c006994520f3a4bb1d47a6afe5c58ff856497ce
author Frank Li <Frank.Li@freescale.com> 1367935724 +0000
committer David S. Miller <davem@davemloft.net> 1368044010 -0700

net: fec: fix kernel oops when plug/unplug cable many times

reproduce steps
 1. flood ping from other machine
 	ping -f -s 41000 IP
 2. run below script
    while [ 1 ]; do ethtool -s eth0 autoneg off;
    sleep 3;ethtool -s eth0 autoneg on; sleep 4; done;

You can see oops in one hour.

The reason is fec_restart clear BD but NAPI may use it.
The solution is disable NAPI and stop xmit when reset BD.
disable NAPI may sleep, so fec_restart can't be call in
atomic context.

Signed-off-by: Frank Li <Frank.Li@freescale.com>
Reviewed-by: Lucas Stach <l.stach@pengutronix.de>
Tested-by: Lucas Stach <l.stach@pengutronix.de>
Signed-off-by: David S. Miller <davem@davemloft.net>