From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ben Hutchings Subject: Re: [v1 PATCH] ucc_geth: fix ethtool set ring param bug Date: Wed, 01 Sep 2010 14:42:30 +0100 Message-ID: <1283348550.2268.7.camel@achroite.uk.solarflarecom.com> References: <1283179677-21262-1-git-send-email-liang.li@windriver.com> <1283305429-8426-1-git-send-email-liang.li@windriver.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: leoli@freescale.com, davem@davemloft.net, avorontsov@ru.mvista.com, netdev@vger.kernel.org, linuxppc-dev@ozlabs.org To: Liang Li Return-path: Received: from mail.solarflare.com ([216.237.3.220]:10148 "EHLO exchange.solarflare.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753617Ab0IANmd (ORCPT ); Wed, 1 Sep 2010 09:42:33 -0400 In-Reply-To: <1283305429-8426-1-git-send-email-liang.li@windriver.com> Sender: netdev-owner@vger.kernel.org List-ID: On Wed, 2010-09-01 at 09:43 +0800, Liang Li wrote: > It's common sense that when we should do change to driver ring > desc/buffer etc only after 'stop/shutdown' the device. When we > do change while devices/driver is running, kernel oops occur: [...] > - ug_info->bdRingLenRx[queue] = ring->rx_pending; > - ug_info->bdRingLenTx[queue] = ring->tx_pending; > - > if (netif_running(netdev)) { > - /* FIXME: restart automatically */ > - printk(KERN_INFO > - "Please re-open the interface.\n"); > + u16 rx_t; > + u16 tx_t; > + printk(KERN_INFO "Stopping interface %s.\n", netdev->name); > + ucc_geth_close(netdev); > + > + rx_t = ug_info->bdRingLenRx[queue]; > + tx_t = ug_info->bdRingLenTx[queue]; > + > + ug_info->bdRingLenRx[queue] = ring->rx_pending; > + ug_info->bdRingLenTx[queue] = ring->tx_pending; > + > + printk(KERN_INFO "Reactivating interface %s.\n", netdev->name); > + ret = ucc_geth_open(netdev); > + if (ret) { > + printk(KERN_WARNING "uec_set_ringparam: set ring param for running" > + " interface %s failed. Please try to make the interface " > + " down, then try again.\n", netdev->name); > + ug_info->bdRingLenRx[queue] = rx_t; > + ug_info->bdRingLenTx[queue] = tx_t; > + } [...] Bringing the interface down will call ucc_geth_close(), which will try to free resources that have not been allocated! If you cannot roll back a failed change then at least use dev_close() and dev_open() rather than calling ucc_geth_{close,open}() directly, so that the interface state is updated correctly. Or just refuse to make the change if the interface is up. Ben. -- Ben Hutchings, Senior Software Engineer, Solarflare Communications Not speaking for my employer; that's the marketing department's job. They asked us to note that Solarflare product names are trademarked.