From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Hemminger Subject: Re: [RFC] net: napi fix Date: Thu, 13 Dec 2007 10:22:33 -0800 Message-ID: <20071213102233.3727e9a0@freepuppy.rosehill> References: <47602B77.2090202@intel.com> <47613E22.6060705@myri.com> <20071213.061938.86541759.davem@davemloft.net> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: gallatin@myri.com, joonwpark81@gmail.com, auke-jan.h.kok@intel.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, jgarzik@pobox.com, jesse.brandeburg@intel.com To: David Miller Return-path: Received: from smtp2.linux-foundation.org ([207.189.120.14]:35769 "EHLO smtp2.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752611AbXLMSaN (ORCPT ); Thu, 13 Dec 2007 13:30:13 -0500 In-Reply-To: <20071213.061938.86541759.davem@davemloft.net> Sender: netdev-owner@vger.kernel.org List-ID: On Thu, 13 Dec 2007 06:19:38 -0800 (PST) David Miller wrote: > From: Andrew Gallatin > Date: Thu, 13 Dec 2007 09:13:54 -0500 > > > If the netif_running() check is indeed required to make a device break > > out of napi polling and respond to an ifconfig down, then I think the > > netif_running() check should be moved up into net_rx_action() to avoid > > potential for driver complexity and bugs like the ones you found. > > That, or something like it, definitely sounds reasonable and much > better than putting the check into every driver :-) > -- > 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 It is not possible to do netif_running() check in generic code as currently written because of the case of devices where a single NAPI object is being used to handle two devices. The association between napi and netdevice is M to N. There are cases like niu that have multiple NAPI's and one netdevice; and devices like sky2 that can have one NAPI and 2 netdevice's. The existing pointer from napi to netdevice is only used by netconsole now. For devices like sky2 it means that netconsole can't work on the the second port which is a not a big problem. But adding a netif_running() check would be a big issue. -- Stephen Hemminger