Subject: Re: [PATCH] drivers/net: remove network drivers' last few uses of IRQF_SAMPLE_RANDOM

From: Jeff Garzik <[email-masked]>
Date: Thu, 15 May 2008 18:42:06 -0400

Brandeburg, Jesse wrote:
> we've been hearing rumblings of big customers wanting (maybe requiring)
> wired network drivers from Intel to  advertise this flag.  Jeff have you
> heard of such?
> 
> I think the argument is that a headless system (no keyboard/mouse, no
> soundcard, probably no video) with a libata based driver and a network
> driver without IRQF_SAMPLE_RANDOM has *no* sources of entropy.  In this
> case the argument is very strong for at least *some* source of entropy
> from interrupts so that randomness can get some external input.  Just
> try rebuilding a kernel RPM over an ssh session and you'll see what I
> mean.
> 
> In short, I agree with Alan's IRQF_SAMPLE_DUBIOUS, and know of Linux
> customers who also want the same.

So I guess a good message for customers might be:

Don't depend on an entropy source whose volume decreases as workload and 
network traffic increase.

	Jeff