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 B8720C636D6 for ; Tue, 7 Feb 2023 13:51:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231258AbjBGNv0 (ORCPT ); Tue, 7 Feb 2023 08:51:26 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34046 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229565AbjBGNvY (ORCPT ); Tue, 7 Feb 2023 08:51:24 -0500 X-Greylist: delayed 60 seconds by postgrey-1.37 at lindbergh.monkeyblade.net; Tue, 07 Feb 2023 05:51:20 PST Received: from smtpcmd03116.aruba.it (smtpcmd03116.aruba.it [62.149.158.116]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 733D8EF8B for ; Tue, 7 Feb 2023 05:51:20 -0800 (PST) Received: from [192.168.1.189] ([213.215.163.55]) by Aruba Outgoing Smtp with ESMTPSA id POMRpOrLjQC6APOMSpnlcj; Tue, 07 Feb 2023 14:50:17 +0100 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=aruba.it; s=a1; t=1675777817; bh=NcFSD1+hQkDyhML9faTlgcz6QoKVti5xKqEWWp0kIPQ=; h=Subject:From:To:Date:Content-Type:MIME-Version; b=GQ4ZVZoTUQiZ0bHywdXm2iNKSQwKGsDqoXPfhrLNIpC+Pvlv2g3MAbGgF5kd0zkJv 9YT/wWJtNSgp1iNoihuXViqU/eolc+MZ0BpcbUuBDljIPLfglQ6sEz+i5FU2OO7z3A wlk+JcPHxoVl+aZP4hkikqQvasQ6g7wkKdELTgQSvA+zYdoCNCsu0Z/JOWhdjwZIRS on/kUbqElLF3h4g17M5O4nreU2JMcOxNtWASrt4Rg5b0KwueOpNok8j3Z05Wu0wBiP +K8f6Q+ZH71jxTzg+Xc2t/N4nF9ZxwOQFwqqbTR9MZNYBPv9OlC+2pCNx3pWWLHZv5 ZHN/3Rvca0WqA== Message-ID: <1ae01ab918876941dc57d01d4c2f1d7376dda87b.camel@egluetechnologies.com> Subject: Re: [PATCH v2] can: j1939: do not wait 250 ms if the same addr was already claimed From: Devid Antonio Filoni To: Oleksij Rempel , Robin van der Gracht , Oliver Hartkopp , Marc Kleine-Budde Cc: Oleksij Rempel , kernel@pengutronix.de, "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , linux-can@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Date: Tue, 07 Feb 2023 14:50:15 +0100 In-Reply-To: <20221126102840.GA21761@pengutronix.de> References: <20221124051611.GA7870@pengutronix.de> <20221125170418.34575-1-devid.filoni@egluetechnologies.com> <20221126102840.GA21761@pengutronix.de> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.44.4-0ubuntu1 MIME-Version: 1.0 X-CMAE-Envelope: MS4xfHjTsmG/3kzQnWEX/yQougaeflBWS+XaKBGWU4V8UDcseLaVHyFCE9JSBHXVmUsVWEPWtvKkARZggLEfHIuv4nJf7v4bOEMxFgXQcKoN//sqtcKHNzrA Zv7AkeePhZKn9JrhUmqKhQbmTzg9uXS9N6SEwrz6gyNAdC4Vlug/cbL3LkcVfdcOmbZLJI7te/K3uU4FTAbiJQFEE/kX5ocDXTUejTmodZZeUi5wRXiPqhsb OeZkBLZAAijGiCZoTXdH/I4J+d/12pqU2O0KmUZSIB3NQQkXlAPIeQIvLo/w0IFe5Z8Qo/wkNNcZgVDJh+enPklAqbZxmBWrdgl2D6YiOmtY+tc59JeJqKXO Hb+hcluVAaPVxLOoBpkp+sGnysQq1OAaKIS0Aazw3ucCu2vmTMFoUuAqw5u/hg7VDTT6MKoIjE2rbmA0s9Gwid6z21QE3IcWh2IIa5DxcJeqChroebYssoWS BGyIEXAM7l374FVzt8bz5+8QTSbijvD4fn3rqvzVeCJfeM6smlTsMxW4PM9FCzFhdLIrDS44ebdwKRLfnxvYHKFg1+S+y/TSMmsFXDxxauwb3CweVMxRf+qM M2dd8JdgyXytwouHxjqH2FB5 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, 2022-11-26 at 11:28 +0100, Oleksij Rempel wrote: > On Fri, Nov 25, 2022 at 06:04:18PM +0100, Devid Antonio Filoni wrote: > > The ISO 11783-5 standard, in "4.5.2 - Address claim requirements", stat= es: > > d) No CF shall begin, or resume, transmission on the network until 25= 0 > > ms after it has successfully claimed an address except when > > responding to a request for address-claimed. > >=20 > > But "Figure 6" and "Figure 7" in "4.5.4.2 - Address-claim > > prioritization" show that the CF begins the transmission after 250 ms > > from the first AC (address-claimed) message even if it sends another AC > > message during that time window to resolve the address contention with > > another CF. > >=20 > > As stated in "4.4.2.3 - Address-claimed message": > > In order to successfully claim an address, the CF sending an address > > claimed message shall not receive a contending claim from another CF > > for at least 250 ms. > >=20 > > As stated in "4.4.3.2 - NAME management (NM) message": > > 1) A commanding CF can > > d) request that a CF with a specified NAME transmit the address- > > claimed message with its current NAME. > > 2) A target CF shall > > d) send an address-claimed message in response to a request for a > > matching NAME > >=20 > > Taking the above arguments into account, the 250 ms wait is requested > > only during network initialization. > >=20 > > Do not restart the timer on AC message if both the NAME and the address > > match and so if the address has already been claimed (timer has expired= ) > > or the AC message has been sent to resolve the contention with another > > CF (timer is still running). > >=20 > > Signed-off-by: Devid Antonio Filoni >=20 > Acked-by: Oleksij Rempel >=20 > > --- > > v1 -> v2: Added ISO 11783-5 standard references > >=20 > > net/can/j1939/address-claim.c | 40 +++++++++++++++++++++++++++++++++++ > > 1 file changed, 40 insertions(+) > >=20 > > diff --git a/net/can/j1939/address-claim.c b/net/can/j1939/address-clai= m.c > > index f33c47327927..ca4ad6cdd5cb 100644 > > --- a/net/can/j1939/address-claim.c > > +++ b/net/can/j1939/address-claim.c > > @@ -165,6 +165,46 @@ static void j1939_ac_process(struct j1939_priv *pr= iv, struct sk_buff *skb) > > * leaving this function. > > */ > > ecu =3D j1939_ecu_get_by_name_locked(priv, name); > > + > > + if (ecu && ecu->addr =3D=3D skcb->addr.sa) { > > + /* The ISO 11783-5 standard, in "4.5.2 - Address claim > > + * requirements", states: > > + * d) No CF shall begin, or resume, transmission on the > > + * network until 250 ms after it has successfully claimed > > + * an address except when responding to a request for > > + * address-claimed. > > + * > > + * But "Figure 6" and "Figure 7" in "4.5.4.2 - Address-claim > > + * prioritization" show that the CF begins the transmission > > + * after 250 ms from the first AC (address-claimed) message > > + * even if it sends another AC message during that time window > > + * to resolve the address contention with another CF. > > + * > > + * As stated in "4.4.2.3 - Address-claimed message": > > + * In order to successfully claim an address, the CF sending > > + * an address claimed message shall not receive a contending > > + * claim from another CF for at least 250 ms. > > + * > > + * As stated in "4.4.3.2 - NAME management (NM) message": > > + * 1) A commanding CF can > > + * d) request that a CF with a specified NAME transmit > > + * the address-claimed message with its current NAME. > > + * 2) A target CF shall > > + * d) send an address-claimed message in response to a > > + * request for a matching NAME > > + * > > + * Taking the above arguments into account, the 250 ms wait is > > + * requested only during network initialization. > > + * > > + * Do not restart the timer on AC message if both the NAME and > > + * the address match and so if the address has already been > > + * claimed (timer has expired) or the AC message has been sent > > + * to resolve the contention with another CF (timer is still > > + * running). > > + */ > > + goto out_ecu_put; > > + } > > + > > if (!ecu && j1939_address_is_unicast(skcb->addr.sa)) > > ecu =3D j1939_ecu_create_locked(priv, name); > > =20 > > --=20 > > 2.34.1 > >=20 > >=20 >=20 Hello, I noticed that this patch has not been integrated in upstream yet. Are there problems with it? Thank you, Devid