Subject: Re: [RFC] net: napi fix

From: "Kok, Auke" <[email-masked]>
Date: Wed, 12 Dec 2007 10:41:59 -0800

David Miller wrote:
> From: Andrew Gallatin <[email-masked]>
> Date: Wed, 12 Dec 2007 12:29:23 -0500
> 
>> Is the netif_running() check even required?
> 
> No, it is not.
> 
> When a device is brought down, one of the first things
> that happens is that we wait for all pending NAPI polls
> to complete, then block any new polls from starting.

I think this was previously (pre-2.6.24) not the case, which is why e1000 et al
has this check as well and that's exactly what is causing most of the
net_rx_action oopses in the first place. Without the netif_running() check
previously the drivers were just unusable with NAPI and prone to many races with
down (i.e. touching some ethtool ioctl which wants to do a reset while routing
small packets at high numbers). that's why we added the netif_running() check in
the first place :)

There might be more drivers lurking that need this change...

Auke