From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 86BF9C76190 for ; Fri, 26 Jul 2019 12:51:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 666EB2238C for ; Fri, 26 Jul 2019 12:51:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726346AbfGZMu4 (ORCPT ); Fri, 26 Jul 2019 08:50:56 -0400 Received: from relay7-d.mail.gandi.net ([217.70.183.200]:38407 "EHLO relay7-d.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726000AbfGZMu4 (ORCPT ); Fri, 26 Jul 2019 08:50:56 -0400 X-Originating-IP: 86.250.200.211 Received: from localhost (lfbn-1-17395-211.w86-250.abo.wanadoo.fr [86.250.200.211]) (Authenticated sender: antoine.tenart@bootlin.com) by relay7-d.mail.gandi.net (Postfix) with ESMTPSA id 89D6C20004; Fri, 26 Jul 2019 12:50:53 +0000 (UTC) Date: Fri, 26 Jul 2019 14:50:53 +0200 From: Antoine Tenart To: Matteo Croce Cc: netdev@vger.kernel.org, Antoine Tenart , Maxime Chevallier , Marcin Wojtas , Stefan Chulski , LKML Subject: Re: [PATCH net] mvpp2: refactor MTU change code Message-ID: <20190726125053.GA5031@kwain> References: <20190725231931.24073-1-mcroce@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20190725231931.24073-1-mcroce@redhat.com> User-Agent: Mutt/1.12.0 (2019-05-25) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Hi Matteo, On Fri, Jul 26, 2019 at 01:19:31AM +0200, Matteo Croce wrote: > The MTU change code can call napi_disable() with the device already down, > leading to a deadlock. Also, lot of code is duplicated unnecessarily. > > Rework mvpp2_change_mtu() to avoid the deadlock and remove duplicated code. > > Signed-off-by: Matteo Croce As this is a fix sent to net, you could add a Fixes: tag. Otherwise this looks good, Acked-by: Antoine Tenart Thanks! Antoine > --- > .../net/ethernet/marvell/mvpp2/mvpp2_main.c | 41 ++++++------------- > 1 file changed, 13 insertions(+), 28 deletions(-) > > diff --git a/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c b/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c > index 2f7286bd203b..60eb98f99571 100644 > --- a/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c > +++ b/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c > @@ -3612,6 +3612,7 @@ static int mvpp2_set_mac_address(struct net_device *dev, void *p) > static int mvpp2_change_mtu(struct net_device *dev, int mtu) > { > struct mvpp2_port *port = netdev_priv(dev); > + bool running = netif_running(dev); > int err; > > if (!IS_ALIGNED(MVPP2_RX_PKT_SIZE(mtu), 8)) { > @@ -3620,40 +3621,24 @@ static int mvpp2_change_mtu(struct net_device *dev, int mtu) > mtu = ALIGN(MVPP2_RX_PKT_SIZE(mtu), 8); > } > > - if (!netif_running(dev)) { > - err = mvpp2_bm_update_mtu(dev, mtu); > - if (!err) { > - port->pkt_size = MVPP2_RX_PKT_SIZE(mtu); > - return 0; > - } > - > - /* Reconfigure BM to the original MTU */ > - err = mvpp2_bm_update_mtu(dev, dev->mtu); > - if (err) > - goto log_error; > - } > - > - mvpp2_stop_dev(port); > + if (running) > + mvpp2_stop_dev(port); > > err = mvpp2_bm_update_mtu(dev, mtu); > - if (!err) { > + if (err) { > + netdev_err(dev, "failed to change MTU\n"); > + /* Reconfigure BM to the original MTU */ > + mvpp2_bm_update_mtu(dev, dev->mtu); > + } else { > port->pkt_size = MVPP2_RX_PKT_SIZE(mtu); > - goto out_start; > } > > - /* Reconfigure BM to the original MTU */ > - err = mvpp2_bm_update_mtu(dev, dev->mtu); > - if (err) > - goto log_error; > - > -out_start: > - mvpp2_start_dev(port); > - mvpp2_egress_enable(port); > - mvpp2_ingress_enable(port); > + if (running) { > + mvpp2_start_dev(port); > + mvpp2_egress_enable(port); > + mvpp2_ingress_enable(port); > + } > > - return 0; > -log_error: > - netdev_err(dev, "failed to change MTU\n"); > return err; > } > > -- > 2.21.0 > -- Antoine Ténart, Bootlin Embedded Linux and Kernel engineering https://bootlin.com