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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B2A12C433F5 for ; Wed, 9 Feb 2022 21:52:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233931AbiBIVwC (ORCPT ); Wed, 9 Feb 2022 16:52:02 -0500 Received: from gmail-smtp-in.l.google.com ([23.128.96.19]:42010 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234068AbiBIVwA (ORCPT ); Wed, 9 Feb 2022 16:52:00 -0500 Received: from mail-ej1-x62a.google.com (mail-ej1-x62a.google.com [IPv6:2a00:1450:4864:20::62a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 07BBBDF498A4 for ; Wed, 9 Feb 2022 13:52:02 -0800 (PST) Received: by mail-ej1-x62a.google.com with SMTP id p15so10827732ejc.7 for ; Wed, 09 Feb 2022 13:52:01 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=RZ84TpOHexbTMnfVb02UAjOHGkMGSzUm5IbMzEHywhs=; b=Yngp9nolKlgTKdaDzf6CJbyRUPDr0kChoh0km0udJ+FBsTC4ro570A1nHI6IHUgWzY ggGUpPHmLqZgN9+C+y7J0OIM6G4kbyKknzxxfdx+VVHrkPwRVKaF2WHByxRKXnBQu9vF 5pKD0/rcwWs2qWmXGgtGRQca3nmuNBVetvB/MMvG/CtoFrtyILFWBJkarxGKo8xOxn5U v4OHXKxaXFYD9XGgrJ98T6YQ12+pxgJ5y8Sd4nZFTdGwlOJ0j5m54mGdsMQQh2MqOISg A5FEQSV+p6EjAgU4MKC3euAudjsFrgSPQxSr+bSE0vWsPS58nrA3PINLesDsMNaUUG1R g8Tw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=RZ84TpOHexbTMnfVb02UAjOHGkMGSzUm5IbMzEHywhs=; b=W86oQ2UsGQvlGl2m1TqLShokUfRj6ziocV7KwNCNrUm8KGPXv2o7M7X3BR1cn1sTwj OnlT+4hX9/JFPLs5Mq6zQuMei57xyJ8lJAzWy2+ZtNswWJVLjy9GAvmhFBhlmiMm+Wbi PZEsohdxhlhrEWbKvOk55yTWWF5qdtDco6DII35W4+dMH6toK8GbzlSul/PYFj3enRvF 2qlIu4lPzNBvSEmnJuG4f6FD0SZuCVJbXCQXa0V5OFBUc9apIqmr+46N/banRVcdFvBJ zGS8Ww6Wr0Rn8RGhfkcy9QiE0eNr2tTo8nZb3Km59RF9y8K118XfjgMqAzicJwspnpff Ph0Q== X-Gm-Message-State: AOAM530MEBIG42S8y4zwD4YMsLbkd/y4E61FaTiCeHk9UyCoI7xtzhWF Bj78iVLtG3FU/iPy2f6V+sy/MCVZ3fs= X-Google-Smtp-Source: ABdhPJzX90kAbKgdk7lZZcd7HgbmlPsWhJYOvaiNw9IZplS08KQWdAq1Yr/obyb1wPu+doqfpHlHFA== X-Received: by 2002:a17:907:1c97:: with SMTP id nb23mr3803834ejc.92.1644443520387; Wed, 09 Feb 2022 13:52:00 -0800 (PST) Received: from skbuf ([188.27.184.105]) by smtp.gmail.com with ESMTPSA id q5sm5631438eds.82.2022.02.09.13.51.58 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 09 Feb 2022 13:51:59 -0800 (PST) Date: Wed, 9 Feb 2022 23:51:58 +0200 From: Vladimir Oltean To: Luiz Angelo Daros de Luca Cc: netdev@vger.kernel.org, linus.walleij@linaro.org, andrew@lunn.ch, vivien.didelot@gmail.com, f.fainelli@gmail.com, davem@davemloft.net, kuba@kernel.org, alsi@bang-olufsen.dk, arinc.unal@arinc9.com Subject: Re: [PATCH net-next 1/2] net: dsa: tag_rtl8_4: add rtl8_4t tailing variant Message-ID: <20220209215158.qdjg7ko4epylwuv7@skbuf> References: <20220209211312.7242-1-luizluca@gmail.com> <20220209211312.7242-2-luizluca@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220209211312.7242-2-luizluca@gmail.com> Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Re: title. Tail or trailing? On Wed, Feb 09, 2022 at 06:13:11PM -0300, Luiz Angelo Daros de Luca wrote: > +static inline void rtl8_4_write_tag(struct sk_buff *skb, struct net_device *dev, > + char *tag) > { > struct dsa_port *dp = dsa_slave_to_port(dev); > - __be16 *tag; > - > - skb_push(skb, RTL8_4_TAG_LEN); > - > - dsa_alloc_etype_header(skb, RTL8_4_TAG_LEN); > - tag = dsa_etype_header_pos_tx(skb); > + __be16 *tag16 = (__be16 *)tag; Can the tail tag be aligned to an odd offset? In that case, should you access byte by byte, maybe? I'm not sure how arches handle this. > > /* Set Realtek EtherType */ > - tag[0] = htons(ETH_P_REALTEK); > + tag16[0] = htons(ETH_P_REALTEK); > > /* Set Protocol; zero REASON */ > - tag[1] = htons(FIELD_PREP(RTL8_4_PROTOCOL, RTL8_4_PROTOCOL_RTL8365MB)); > + tag16[1] = htons(FIELD_PREP(RTL8_4_PROTOCOL, RTL8_4_PROTOCOL_RTL8365MB)); > > /* Zero FID_EN, FID, PRI_EN, PRI, KEEP; set LEARN_DIS */ > - tag[2] = htons(FIELD_PREP(RTL8_4_LEARN_DIS, 1)); > + tag16[2] = htons(FIELD_PREP(RTL8_4_LEARN_DIS, 1)); > > /* Zero ALLOW; set RX (CPU->switch) forwarding port mask */ > - tag[3] = htons(FIELD_PREP(RTL8_4_RX, BIT(dp->index))); > + tag16[3] = htons(FIELD_PREP(RTL8_4_RX, BIT(dp->index))); > +} > + > +static struct sk_buff *rtl8_4_tag_xmit(struct sk_buff *skb, > + struct net_device *dev) > +{ > + skb_push(skb, RTL8_4_TAG_LEN); > + > + dsa_alloc_etype_header(skb, RTL8_4_TAG_LEN); > + > + rtl8_4_write_tag(skb, dev, dsa_etype_header_pos_tx(skb)); > > return skb; > } > > -static struct sk_buff *rtl8_4_tag_rcv(struct sk_buff *skb, > - struct net_device *dev) > +static struct sk_buff *rtl8_4t_tag_xmit(struct sk_buff *skb, > + struct net_device *dev) > +{ Why don't you want to add: if (skb->ip_summed == CHECKSUM_PARTIAL && skb_checksum_help(skb)) return NULL; and then you'll make this tagging protocol useful in production too. > + rtl8_4_write_tag(skb, dev, skb_put(skb, RTL8_4_TAG_LEN)); > + > + return skb; > +}