Please format your commit message text to 80 columns.
Ok, no problem. I did not know that 80 columns limitation applies also for commit messages.
You should be instead preventing the transmit method from being invoked when it might be possible that a request cannot be satisfied. This means that at the end of a transmit request, you must stop the queue if a packet with the maximum number of possible descriptors cannot be satisfied. Then it is impossible for the transmit function to be invoked in a situation where it would need to fail for lack of available transmit descriptors. This is why drivers decided whether to stop their TX queues based upon calculations involving MAX_SKB_FRAGS.
Hmm, correct me if I'm wrong ... but the driver and hardware does not support scatter-gather DMA. So fragmented skbs can't be passed to ndo_start_xmit function and each skb passed to the function represents one packet and one descriptor in tx_ring. I do not think that in this caseit makes sense to to involve MAX_SKB_FRAGS in any calculation and the queue should be stopped in the moment when it gets full. But maybe I am missing something, I am no expert in this kind of stuff. -- Ondrej Puzman -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/