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=-13.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 186F4C2BB48 for ; Tue, 15 Dec 2020 16:49:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C3C62207AD for ; Tue, 15 Dec 2020 16:49:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731194AbgLOQs4 (ORCPT ); Tue, 15 Dec 2020 11:48:56 -0500 Received: from relay2-d.mail.gandi.net ([217.70.183.194]:40859 "EHLO relay2-d.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728896AbgLOQsn (ORCPT ); Tue, 15 Dec 2020 11:48:43 -0500 X-Originating-IP: 86.202.109.140 Received: from localhost (lfbn-lyo-1-13-140.w86-202.abo.wanadoo.fr [86.202.109.140]) (Authenticated sender: alexandre.belloni@bootlin.com) by relay2-d.mail.gandi.net (Postfix) with ESMTPSA id C19DE40002; Tue, 15 Dec 2020 16:47:56 +0000 (UTC) Date: Tue, 15 Dec 2020 17:47:56 +0100 From: Alexandre Belloni To: Vladimir Oltean Cc: Tobias Waldekranz , "David S . Miller" , Jakub Kicinski , netdev@vger.kernel.org, UNGLinuxDriver@microchip.com, Andrew Lunn , Florian Fainelli , Vivien Didelot , Claudiu Manoil Subject: Re: [RFC PATCH net-next 08/16] net: mscc: ocelot: avoid unneeded "lp" variable in LAG join Message-ID: <20201215164756.GL1781038@piout.net> References: <20201208120802.1268708-1-vladimir.oltean@nxp.com> <20201208120802.1268708-9-vladimir.oltean@nxp.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201208120802.1268708-9-vladimir.oltean@nxp.com> Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On 08/12/2020 14:07:54+0200, Vladimir Oltean wrote: > The index of the LAG is equal to the logical port ID that all the > physical port members have, which is further equal to the index of the > first physical port that is a member of the LAG. > > The code gets a bit carried away with logic like this: > > if (a == b) > c = a; > else > c = b; > > which can be simplified, of course, into: > > c = b; > > (with a being port, b being lp, c being lag) > > This further makes the "lp" variable redundant, since we can use "lag" > everywhere where "lp" (logical port) was used. So instead of a "c = b" > assignment, we can do a complete deletion of b. Only one comment here: > > if (bond_mask) { > lp = __ffs(bond_mask); > ocelot->lags[lp] = 0; > } > > lp was clobbered before, because it was used as a temporary variable to > hold the new smallest port ID from the bond. Now that we don't have "lp" > any longer, we'll just avoid the temporary variable and zeroize the > bonding mask directly. > > Signed-off-by: Vladimir Oltean Reviewed-by: Alexandre Belloni > --- > drivers/net/ethernet/mscc/ocelot.c | 16 ++++++---------- > 1 file changed, 6 insertions(+), 10 deletions(-) > > diff --git a/drivers/net/ethernet/mscc/ocelot.c b/drivers/net/ethernet/mscc/ocelot.c > index 30dee1f957d1..080fd4ce37ea 100644 > --- a/drivers/net/ethernet/mscc/ocelot.c > +++ b/drivers/net/ethernet/mscc/ocelot.c > @@ -1291,28 +1291,24 @@ int ocelot_port_lag_join(struct ocelot *ocelot, int port, > struct net_device *bond) > { > u32 bond_mask = 0; > - int lag, lp; > + int lag; > > ocelot->ports[port]->bond = bond; > > bond_mask = ocelot_get_bond_mask(ocelot, bond); > > - lp = __ffs(bond_mask); > + lag = __ffs(bond_mask); > > /* If the new port is the lowest one, use it as the logical port from > * now on > */ > - if (port == lp) { > - lag = port; > + if (port == lag) { > ocelot->lags[port] = bond_mask; > bond_mask &= ~BIT(port); > - if (bond_mask) { > - lp = __ffs(bond_mask); > - ocelot->lags[lp] = 0; > - } > + if (bond_mask) > + ocelot->lags[__ffs(bond_mask)] = 0; > } else { > - lag = lp; > - ocelot->lags[lp] |= BIT(port); > + ocelot->lags[lag] |= BIT(port); > } > > ocelot_setup_lag(ocelot, lag); > -- > 2.25.1 > -- Alexandre Belloni, Bootlin Embedded Linux and Kernel engineering https://bootlin.com