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=-5.0 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 7DAF7FA372A for ; Wed, 16 Oct 2019 12:03:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 53BAF2067B for ; Wed, 16 Oct 2019 12:03:49 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=lunn.ch header.i=@lunn.ch header.b="r3/LAoaD" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388547AbfJPMDs (ORCPT ); Wed, 16 Oct 2019 08:03:48 -0400 Received: from vps0.lunn.ch ([185.16.172.187]:48160 "EHLO vps0.lunn.ch" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726845AbfJPMDs (ORCPT ); Wed, 16 Oct 2019 08:03:48 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lunn.ch; s=20171124; h=In-Reply-To:Content-Type:MIME-Version:References:Message-ID: Subject:Cc:To:From:Date:Sender:Reply-To:Content-Transfer-Encoding:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Id:List-Help:List-Unsubscribe:List-Subscribe: List-Post:List-Owner:List-Archive; bh=NBc8vNMTMHQOQr0qJqJ1ykg36+K8LkXUK+za7gCE8KM=; b=r3/LAoaD96vbDU2j+fvPIFoD20 SGEOx5nSaf0Ts1XkiSI0c4QtBHAi5E2p/7fvmhYK18KKifoC6D6/42VS/1xilxmI/n9GD9KuFHOVq eloXC0prcgrF1TWl49J3B7JCgz54XjEObpPRSiY6Z9bOiuiRtgyQWymKFJwjqQQXbnco=; Received: from andrew by vps0.lunn.ch with local (Exim 4.92.2) (envelope-from ) id 1iKi1p-0007DI-GX; Wed, 16 Oct 2019 14:03:45 +0200 Date: Wed, 16 Oct 2019 14:03:45 +0200 From: Andrew Lunn To: Marek Vasut Cc: netdev@vger.kernel.org, "David S . Miller" , Florian Fainelli , George McCollister , Tristram Ha , Woojung Huh Subject: Re: [PATCH V2 2/2] net: dsa: microchip: Add shared regmap mutex Message-ID: <20191016120345.GC4780@lunn.ch> References: <20191013193238.1638-1-marex@denx.de> <20191013193238.1638-2-marex@denx.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20191013193238.1638-2-marex@denx.de> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Sun, Oct 13, 2019 at 09:32:38PM +0200, Marek Vasut wrote: > The KSZ driver uses one regmap per register width (8/16/32), each with > it's own lock, but accessing the same set of registers. In theory, it > is possible to create a race condition between these regmaps, although > the underlying bus (SPI or I2C) locking should assure nothing bad will > really happen and the accesses would be correct. > > To make the driver do the right thing, add one single shared mutex for > all the regmaps used by the driver instead. This assures that even if > some future hardware is on a bus which does not serialize the accesses > the same way SPI or I2C does, nothing bad will happen. > > Note that the status_mutex was unused and only initied, hence it was > renamed and repurposed as the regmap mutex. > > Signed-off-by: Marek Vasut Apart from the reverse Christmas tree: Reviewed-by: Andrew Lunn Andrew