e100: Fix the TX workqueue race

Nothing stops the workqueue being left to run in parallel with close or a
few other operations. This causes double unmaps and the like.

See kerneloops.org #1041230 for an example
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/e100.c

@@ -166,6 +166,7 @@
 #include <linux/ethtool.h>
 #include <linux/string.h>
 #include <linux/firmware.h>
+#include <linux/rtnetlink.h>
 #include <asm/unaligned.h>
 
 
@@ -2265,8 +2266,13 @@ static void e100_tx_timeout_task(struct work_struct *work)
 
 	DPRINTK(TX_ERR, DEBUG, "scb.status=0x%02X\n",
 		ioread8(&nic->csr->scb.status));
+
+	rtnl_lock();
+	if (netif_running(netdev)) {
 		e100_down(netdev_priv(netdev));
 		e100_up(netdev_priv(netdev));
+	}
+	rtnl_unlock();
 }
 
 static int e100_loopback_test(struct nic *nic, enum loopback loopback_mode)