From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Kok, Auke" Subject: Re: [RFC] net: napi fix Date: Wed, 12 Dec 2007 10:41:59 -0800 Message-ID: <47602B77.2090202@intel.com> References: <47601A73.5010804@myri.com> <20071212.093819.205755031.davem@davemloft.net> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: gallatin@myri.com, joonwpark81@gmail.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, jgarzik@pobox.com, shemminger@linux-foundation.org, Jesse Brandeburg To: David Miller Return-path: Received: from mga03.intel.com ([143.182.124.21]:17060 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751563AbXLLSpC (ORCPT ); Wed, 12 Dec 2007 13:45:02 -0500 In-Reply-To: <20071212.093819.205755031.davem@davemloft.net> Sender: netdev-owner@vger.kernel.org List-ID: David Miller wrote: > From: Andrew Gallatin > 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