From patchwork Tue May 10 09:40:13 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Felix Fietkau X-Patchwork-Id: 12844735 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 412A7C433F5 for ; Tue, 10 May 2022 09:41:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:Message-Id:Date:Subject:Cc :To:From:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:References: List-Owner; bh=0EKnbHyMhb+RbQB5PKTbjD+vBjAOevsOupyyPKhf8Cc=; b=0I4eoBcsDQ/kqv ZTBC3AkdFqQqJAkQ9vl9H51kcCRVoCF04A4YBEjsqFbdbnsV2zL6nJSBWVqKi5Hj4emCz9FfRPfpW GKRGzEEkDMXGCzJ2lJVHShhK8FyCdgxowDyi2B2tXzi5FBAQLnBiYXXGv5R4VgsVwBCk6M9UP3iSB wh+/5HxDT2L3RjqU5FFL2YftYEGPq1oSZ7DXNw7CA8bUeBZ+IFOib+dnOUatBmxpcC5W98sy0JsqA O0unSlKBIzPRfRcr5ok9nm9LD+9iBWJ72QtRkVszszkryfsF5hDFwqqd9Oi7amW0nB7cvQBqVbEPZ V3Y0U3Q+qeFRYtNQJgug==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1noMMj-000uFN-Q4; Tue, 10 May 2022 09:41:13 +0000 Received: from nbd.name ([2a01:4f8:221:3d45::2]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1noMMG-000tzY-6Y; Tue, 10 May 2022 09:40:45 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=nbd.name; s=20160729; h=Content-Transfer-Encoding:MIME-Version:Message-Id:Date:Subject :Cc:To:From:Sender:Reply-To:Content-Type:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: In-Reply-To:References:List-Id:List-Help:List-Unsubscribe:List-Subscribe: List-Post:List-Owner:List-Archive; bh=mCs9O3RJG01sw6qsZslsu692hG4UQ4nY/c7ZXZYpQ7k=; b=YA/qQ9JBLeM2/t9UBwl7vdtyKP fPVHEg/CLYnZKaPDVcnlMphhcN657ekRTJ5EvsJc4XP6wroRqsrh4D0TdYh71PLCDeP32jCRU/GK4 GEK0f7TrBABDVp/03sBk8odbSJHkMolZz+RgOLtmeLy+bASDC9ja//Hnt7T6tiyeUs5c=; Received: from [217.114.218.19] (helo=localhost.localdomain) by ds12 with esmtpsa (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.89) (envelope-from ) id 1noMLu-0005SZ-MI; Tue, 10 May 2022 11:40:22 +0200 From: Felix Fietkau To: Sean Wang , Landen Chao , DENG Qingfang , Andrew Lunn , Vivien Didelot , Florian Fainelli , Vladimir Oltean , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Matthias Brugger Cc: netdev@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mediatek@lists.infradead.org, linux-kernel@vger.kernel.org Subject: [PATCH v2] net: dsa: tag_mtk: add padding for tx packets Date: Tue, 10 May 2022 11:40:13 +0200 Message-Id: <20220510094014.68440-1-nbd@nbd.name> X-Mailer: git-send-email 2.36.1 MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220510_024044_564803_E8762E40 X-CRM114-Status: GOOD ( 11.93 ) X-BeenThere: linux-mediatek@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "Linux-mediatek" Errors-To: linux-mediatek-bounces+linux-mediatek=archiver.kernel.org@lists.infradead.org Padding for transmitted packets needs to account for the special tag. With not enough padding, garbage bytes are inserted by the switch at the end of small packets. Fixes: 5cd8985a1909 ("net-next: dsa: add Mediatek tag RX/TX handler") Signed-off-by: Felix Fietkau --- net/dsa/tag_mtk.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/net/dsa/tag_mtk.c b/net/dsa/tag_mtk.c index 415d8ece242a..1d1f9dbd9e93 100644 --- a/net/dsa/tag_mtk.c +++ b/net/dsa/tag_mtk.c @@ -25,6 +25,14 @@ static struct sk_buff *mtk_tag_xmit(struct sk_buff *skb, u8 xmit_tpid; u8 *mtk_tag; + /* The Ethernet switch we are interfaced with needs packets to be at + * least 64 bytes (including FCS) otherwise their padding might be + * corrupted. With tags enabled, we need to make sure that packets are + * at least 68 bytes (including FCS and tag). + */ + if (__skb_put_padto(skb, ETH_ZLEN + MTK_HDR_LEN, false)) + return NULL; + /* Build the special tag after the MAC Source Address. If VLAN header * is present, it's required that VLAN header and special tag is * being combined. Only in this way we can allow the switch can parse