From: Stephen Hemminger <shemminger@linux-foundation.org>
Date: Mon, 23 Mar 2009 15:45:17 -0700

quoted text
> So you dynamically compute the additional space but if the space was
> an awkward size, could it cause driver to breaks alignment assumptions?

Yes, you'd need to 16-byte align or something like that.

quoted text
> And you didn't fixup the skb that is about to gag in the skb to make
> more space, so transmitting device driver (gfar) is going to overwrite or die.

This particular instance will do the headroom reallocation,
that's unavoidable during the size transition event.

The headroom checks can't ever be removed, but we won't hit
them in the fast path after the adjustment is made by my
patch.
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html