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=-21.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham 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 B60EDC433DB for ; Mon, 11 Jan 2021 14:23:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 906702242A for ; Mon, 11 Jan 2021 14:23:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725988AbhAKOWu (ORCPT ); Mon, 11 Jan 2021 09:22:50 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36024 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728262AbhAKOWu (ORCPT ); Mon, 11 Jan 2021 09:22:50 -0500 Received: from metis.ext.pengutronix.de (metis.ext.pengutronix.de [IPv6:2001:67c:670:201:290:27ff:fe1d:cc33]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B324CC06179F for ; Mon, 11 Jan 2021 06:22:09 -0800 (PST) Received: from gallifrey.ext.pengutronix.de ([2001:67c:670:201:5054:ff:fe8d:eefb] helo=bjornoya.blackshift.org) by metis.ext.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1kyy5A-0007aK-77 for linux-can@vger.kernel.org; Mon, 11 Jan 2021 15:22:08 +0100 Received: from dspam.blackshift.org (localhost [127.0.0.1]) by bjornoya.blackshift.org (Postfix) with SMTP id 22B9E5C0FB5 for ; Mon, 11 Jan 2021 14:19:41 +0000 (UTC) Received: from hardanger.blackshift.org (unknown [172.20.34.65]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-384) server-signature RSA-PSS (4096 bits) server-digest SHA256) (Client did not present a certificate) by bjornoya.blackshift.org (Postfix) with ESMTPS id E92C05C0F94; Mon, 11 Jan 2021 14:19:38 +0000 (UTC) Received: from blackshift.org (localhost [::1]) by hardanger.blackshift.org (OpenSMTPD) with ESMTP id e71e1a34; Mon, 11 Jan 2021 14:19:32 +0000 (UTC) From: Marc Kleine-Budde To: linux-can@vger.kernel.org Cc: Oliver Hartkopp , Vincent Mailhol , Marc Kleine-Budde Subject: [net-next v3 15/15] can: dev: add software tx timestamps Date: Mon, 11 Jan 2021 15:19:30 +0100 Message-Id: <20210111141930.693847-16-mkl@pengutronix.de> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20210111141930.693847-1-mkl@pengutronix.de> References: <20210111141930.693847-1-mkl@pengutronix.de> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-SA-Exim-Connect-IP: 2001:67c:670:201:5054:ff:fe8d:eefb X-SA-Exim-Mail-From: mkl@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-can@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-can@vger.kernel.org From: Vincent Mailhol Call skb_tx_timestamp() within can_put_echo_skb() so that a software tx timestamp gets attached on the skb. There two main reasons to include this call in can_put_echo_skb(): * It easily allow to enable the tx timestamp on all devices with just one small change. * According to Documentation/networking/timestamping.rst, the tx timestamps should be generated in the device driver as close as possible, but always prior to passing the packet to the network interface. During the call to can_put_echo_skb(), the skb gets cloned meaning that the driver should not dereference the skb variable anymore after can_put_echo_skb() returns. This makes can_put_echo_skb() the very last place we can use the skb without having to access the echo_skb[] array. Remarks: * By default, skb_tx_timestamp() does nothing. It needs to be activated by passing the SOF_TIMESTAMPING_TX_SOFTWARE flag either through socket options or control messages. * The hardware rx timestamp of a local loopback message is the hardware tx timestamp. This means that there are no needs to implement SOF_TIMESTAMPING_TX_HARDWARE for CAN sockets. References: Support for the error queue in CAN RAW sockets (which is needed for tx timestamps) was introduced in: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=eb88531bdbfaafb827192d1fc6c5a3fcc4fadd96 Put the call to skb_tx_timestamp() just before adding it to the array: https://lkml.org/lkml/2021/1/10/54 Signed-off-by: Vincent Mailhol Link: https://lore.kernel.org/r/20210110124903.109773-2-mailhol.vincent@wanadoo.fr Signed-off-by: Marc Kleine-Budde --- drivers/net/can/dev/skb.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/net/can/dev/skb.c b/drivers/net/can/dev/skb.c index 53683d4312f1..6a64fe410987 100644 --- a/drivers/net/can/dev/skb.c +++ b/drivers/net/can/dev/skb.c @@ -65,6 +65,8 @@ int can_put_echo_skb(struct sk_buff *skb, struct net_device *dev, /* save frame_len to reuse it when transmission is completed */ can_skb_prv(skb)->frame_len = frame_len; + skb_tx_timestamp(skb); + /* save this skb for tx interrupt echo handling */ priv->echo_skb[idx] = skb; } else { -- 2.29.2