int mc32_send_packet (struct sk_buff * skb, struct net_device * dev);
Transmit a buffer. This normally means throwing the buffer onto the transmit queue as the queue is quite large. If the queue is full then we set tx_busy and return. Once the interrupt handler gets messages telling it to reclaim transmit queue entries we will clear tx_busy and the kernel will start calling this again.
We use cli rather than spinlocks. Since I have no access to an SMP MCA machine I don't plan to change it. It is probably the top performance hit for this driver on SMP however.