On Thu, Jan 2, 2014 at 2:41 PM, David Miller [off-list ref] wrote:

Yes, something like the following untested patch.

I did that initially too, but that doesn't work, because the code
inside the skb_queue_walk() loop ends up calling irlap_send_i_frame()
which calls irlap_queue_xmit(), which does dev_queue_xmit().

Which will do a bh_disable/bh_enable() (as part of spin_[un]lock_bh(), iirc).

So you can't use "spin_lock_irqsave()", because it doesn't nest around
a softirq-disable.

You could use spin_lock_bh(), but if it's true that it's all in a
softirq context, I think it should be safe to just do "spin_lock()".
Afaik, there is nothing that actually does anything in real hardirq
context in there. I *think* all the network _rcv() functions are
called from softirqs, right?

             Linus