Current e1000_xmit_frame spews raw interrupt disabled nag messages when
used with RT kernel patches.  This patch uses spin_trylock_irqsave,
which allows RT patches to properly manage the irq semantics.
Signed-off-by: Mark Huth <mhuth@mvista.com>
Signed-off-by: Auke Kok <auke-jan.h.kok@intel.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
            (adapter->hw.mac_type == e1000_82573))
                e1000_transfer_dhcp_info(adapter, skb);
 
-       local_irq_save(flags);
-       if (!spin_trylock(&tx_ring->tx_lock)) {
+       if (!spin_trylock_irqsave(&tx_ring->tx_lock, flags))
                /* Collision - tell upper layer to requeue */
-               local_irq_restore(flags);
                return NETDEV_TX_LOCKED;
-       }
 
        /* need: count + 2 desc gap to keep tail from touching
         * head, otherwise try next time */