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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id BF42CC4332F for ; Thu, 14 Dec 2023 15:11:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230187AbjLNPLT (ORCPT ); Thu, 14 Dec 2023 10:11:19 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60462 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1573703AbjLNPKW (ORCPT ); Thu, 14 Dec 2023 10:10:22 -0500 Received: from mgamail.intel.com (mgamail.intel.com [192.55.52.88]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7CE27111; Thu, 14 Dec 2023 07:10:28 -0800 (PST) X-IronPort-AV: E=McAfee;i="6600,9927,10924"; a="426261795" X-IronPort-AV: E=Sophos;i="6.04,275,1695711600"; d="scan'208";a="426261795" Received: from orsmga002.jf.intel.com ([10.7.209.21]) by fmsmga101.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 14 Dec 2023 07:10:28 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10924"; a="774400393" X-IronPort-AV: E=Sophos;i="6.04,275,1695711600"; d="scan'208";a="774400393" Received: from smile.fi.intel.com ([10.237.72.54]) by orsmga002.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 14 Dec 2023 07:10:26 -0800 Received: from andy by smile.fi.intel.com with local (Exim 4.97) (envelope-from ) id 1rDnLz-00000005sIR-1rWc; Thu, 14 Dec 2023 17:10:23 +0200 Date: Thu, 14 Dec 2023 17:10:23 +0200 From: Andy Shevchenko To: Kent Gibson Cc: linux-kernel@vger.kernel.org, linux-gpio@vger.kernel.org, brgl@bgdev.pl, linus.walleij@linaro.org Subject: Re: [PATCH v2 4/5] gpiolib: cdev: reduce locking in gpio_desc_to_lineinfo() Message-ID: References: <20231214095814.132400-1-warthog618@gmail.com> <20231214095814.132400-5-warthog618@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20231214095814.132400-5-warthog618@gmail.com> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Dec 14, 2023 at 05:58:13PM +0800, Kent Gibson wrote: > Reduce the time holding the gpio_lock by snapshotting the desc flags, > rather than testing them individually while holding the lock. > > Accept that the calculation of the used field is inherently racy, and > only check the availability of the line from pinctrl if other checks > pass, so avoiding the check for lines that are otherwise in use. ... > - spin_lock_irqsave(&gpio_lock, flags); Shouldn't this be covered by patch 1 (I mean conversion to scoped_guard() instead of spinlock)? -- With Best Regards, Andy Shevchenko