Subject: Re: [ofa-general] NetEffect, iw_nes and kernel warning

From: Stephen Hemminger <[email-masked]>
Date: Tue, 27 Jan 2009 16:17:09 -0800

On Tue, 27 Jan 2009 16:07:50 -0800 (PST)
David Miller <[email-masked]> wrote:

> From: Roland Dreier <[email-masked]>
> Date: Tue, 27 Jan 2009 15:53:16 -0800
> 
> > but actually I still don't see how it's safe for a net driver to
> > call skb_linearize() from its transmit routine, since there's a
> > chance that that will unconditionally enable BHs?
> 
> It's simply not allowed.
> 
> dev_queue_xmit() at a higher level can do __skb_linearize()
> because it does so before doing the rcu_read_lock_bh().

If the device driver can't handle non-linear SKB's then it should
not set NETIF_F_SG.