Re: [PATCH] Prevent netpoll hanging when link is down

[Andi Kleen <ak@xxxxxxx>]

On Thu, Oct 07, 2004 at 10:44:22PM +0200, Colin Leroy wrote:
> On 07 Oct 2004 at 11h10, David S. Miller wrote:
> 
> Hi again, 
> 
> > So, netpoll needs to have the NETIF_F_LLTX stuff added to it.
> 
> This patch should do that. It works OK for me, but I'd like it checked
> before sent upstream...
> 
> However, it doesn't fix the hang. it looks like this hang is really
> coming from sungem.

IMHO it's not needed. Taking xmit_lock is harmless even when
the NETIF_F_LLTX flag is set. 

(or at least it was with my original patchkit. In theory it's 
possible someone changed their driver to take xmit_lock in hard_start_xmit,
but if they did that I would just consider it a driver bug) 

The only drawback is that there won't be a reply when the driver try
lock fails, but netpoll doesn't have a queue for that anyways. You could
probably poll then, but I'm not sure it's a good idea.

-Andi