From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1424842AbcBREn0 (ORCPT ); Wed, 17 Feb 2016 23:43:26 -0500 Received: from shards.monkeyblade.net ([149.20.54.216]:34538 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1424516AbcBREnZ (ORCPT ); Wed, 17 Feb 2016 23:43:25 -0500 Date: Wed, 17 Feb 2016 23:43:21 -0500 (EST) Message-Id: <20160217.234321.1202099534402079240.davem@davemloft.net> To: gregory.clement@free-electrons.com Cc: linux-kernel@vger.kernel.org, netdev@vger.kernel.org, thomas.petazzoni@free-electrons.com, f.fainelli@gmail.com, jason@lakedaemon.net, andrew@lunn.ch, sebastian.hesselbarth@gmail.com, linux-arm-kernel@lists.infradead.org, alior@marvell.com, nadavh@marvell.com, mw@semihalf.com, simon.guinot@sequanux.org, linux@arm.linux.org.uk, w@1wt.eu, timork@marvell.com, nitroshift@yahoo.com Subject: Re: [PATCH v2 net-next 6/8] net: mvneta: bm: add support for hardware buffer management From: David Miller In-Reply-To: <1455636823-14470-7-git-send-email-gregory.clement@free-electrons.com> References: <1455636823-14470-1-git-send-email-gregory.clement@free-electrons.com> <1455636823-14470-7-git-send-email-gregory.clement@free-electrons.com> X-Mailer: Mew version 6.7 on Emacs 24.5 / Mule 6.0 (HANACHIRUSATO) Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.5.12 (shards.monkeyblade.net [149.20.54.216]); Wed, 17 Feb 2016 20:43:24 -0800 (PST) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Gregory CLEMENT Date: Tue, 16 Feb 2016 16:33:41 +0100 > pp->dev = dev; > SET_NETDEV_DEV(dev, &pdev->dev); > > + dev->features = NETIF_F_SG | NETIF_F_IP_CSUM | NETIF_F_TSO; > + dev->hw_features |= dev->features; > + dev->vlan_features |= dev->features; > + dev->priv_flags |= IFF_UNICAST_FLT; > + dev->gso_max_segs = MVNETA_MAX_TSO_SEGS; > + > + err = register_netdev(dev); > + if (err < 0) { > + dev_err(&pdev->dev, "failed to register\n"); > + goto err_free_stats; > + } > + > + pp->id = dev->ifindex; > + > + /* Obtain access to BM resources if enabled and already initialized */ > + bm_node = of_parse_phandle(dn, "buffer-manager", 0); > + if (bm_node && bm_node->data) { This set of changes has a lot of problems. First, the exact moment you call register_netdev() your device must be fully initialized because ->open() can be invoked immediately. This means you must take care of all of this buffer manager stuff before calling register_netdev(). It must precisely be the last thing you invoke in your probe function for this reason. Also you are now adding conditionalized code to every fastpath in your driver, that is rediculous and is going to hurt performance. Add seperate code paths for the HWBM vs SWBM, and register a unique set of netdev_ops as appropriate.