From patchwork Tue Nov 17 13:04:44 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 328057 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=-12.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT 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 1B5E3C64E7D for ; Tue, 17 Nov 2020 13:59:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BBE1D20829 for ; Tue, 17 Nov 2020 13:59:38 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="FfELSIec" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729837AbgKQN72 (ORCPT ); Tue, 17 Nov 2020 08:59:28 -0500 Received: from mail.kernel.org ([198.145.29.99]:50132 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730596AbgKQNRr (ORCPT ); Tue, 17 Nov 2020 08:17:47 -0500 Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 13DE02463D; Tue, 17 Nov 2020 13:17:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1605619066; bh=0iwJuiQzlg0IcIRmnTjdvR37SNEbZGygc+Kl6YTufgk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=FfELSIec9AR3G9Yw2CSO7F3/GK148jlnE3lj9n0PByJsxwrX96UNAtgSiAFLG7b+d oafsoRl3aUeJkaXVVVIqGkTe/+WE5OAzGTAbMU6ByZNe2CM1IWRWAQjMLcoFxTs2oV wxh8hQIz31wOcGpPhYBJA/Q/vhMD1xWIAi+yiyxE= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Vincent Mailhol , Oliver Hartkopp , Marc Kleine-Budde , Sasha Levin Subject: [PATCH 4.19 017/101] can: dev: __can_get_echo_skb(): fix real payload length return value for RTR frames Date: Tue, 17 Nov 2020 14:04:44 +0100 Message-Id: <20201117122113.934953076@linuxfoundation.org> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201117122113.128215851@linuxfoundation.org> References: <20201117122113.128215851@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Oliver Hartkopp [ Upstream commit ed3320cec279407a86bc4c72edc4a39eb49165ec ] The can_get_echo_skb() function returns the number of received bytes to be used for netdev statistics. In the case of RTR frames we get a valid (potential non-zero) data length value which has to be passed for further operations. But on the wire RTR frames have no payload length. Therefore the value to be used in the statistics has to be zero for RTR frames. Reported-by: Vincent Mailhol Signed-off-by: Oliver Hartkopp Link: https://lore.kernel.org/r/20201020064443.80164-1-socketcan@hartkopp.net Fixes: cf5046b309b3 ("can: dev: let can_get_echo_skb() return dlc of CAN frame") Signed-off-by: Marc Kleine-Budde Signed-off-by: Sasha Levin --- drivers/net/can/dev.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/drivers/net/can/dev.c b/drivers/net/can/dev.c index be532eb64baa2..1950b13f22dfc 100644 --- a/drivers/net/can/dev.c +++ b/drivers/net/can/dev.c @@ -493,9 +493,13 @@ struct sk_buff *__can_get_echo_skb(struct net_device *dev, unsigned int idx, u8 */ struct sk_buff *skb = priv->echo_skb[idx]; struct canfd_frame *cf = (struct canfd_frame *)skb->data; - u8 len = cf->len; - *len_ptr = len; + /* get the real payload length for netdev statistics */ + if (cf->can_id & CAN_RTR_FLAG) + *len_ptr = 0; + else + *len_ptr = cf->len; + priv->echo_skb[idx] = NULL; return skb;