From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.14]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 361A7390C9C; Tue, 17 Mar 2026 07:34:29 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=192.198.163.14 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773732871; cv=none; b=AT8U6GzwRrmL4oGkjVdeNcm+qZAvIiSPqIRwqbmN+TzKdkEzqwkTm3v1vpGJKIdpcafFHVyqhdKg/NEX3uwXOOmcIf6tW9HR3teeXXRIdXD3hBGCo5r5iY0DtatlF2VGi+Mauiu0K6B+KuGBwkpRoQVE6JBueylRTl2UOFDa8cU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773732871; c=relaxed/simple; bh=1OJtUNEamh5vO3iFIrEXYFak4q7SIt7T2aherzADZ/g=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=sJin+WTo6SOAFIl4SwBBsbdIFKa9iBGCt2nHp6VhL5V85uqBwzYYvY/ihKKrjGztu0gUI4eZx6rsxeqTSqcC8jji5t+EPv5ZQYztB362MPiwAbgoKrqdmp291Q44HSfO4DPJwVu97EbvDCSvFtwFcA4D7Vy30c2u4KuWdplLKRo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com; spf=pass smtp.mailfrom=linux.intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=M47DaaOu; arc=none smtp.client-ip=192.198.163.14 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="M47DaaOu" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1773732868; x=1805268868; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=1OJtUNEamh5vO3iFIrEXYFak4q7SIt7T2aherzADZ/g=; b=M47DaaOuSzsQO328WpCScWltYGD4pdgiPUxorGYboWTN4VdJ5bhV5HgK ycgZqRjShABovIRAl9mbB1rplIl4VcZupB+COiK3gbIxCgaUvmCnRiLDW 14oPfBjsouJXU622gvO2BQcktn4jsCUgI8WY8nTWT5cqZTi+f8aJ2OIuu laCc4bSV3biqHi/7v+LEiaHEwyolHZvj23jbbfU5KQWTc9OpxHY//aR+G lg/1CmDhYBl0urV5JR+H+jn+fRM9jt7SZPoa74dmem/uDtsUDXX9ZPqP5 GsoD2FLbVK4j3eSdEXvncyrXjHlj8mzrZGGe8l0511L8OqNoGdwFv64PQ A==; X-CSE-ConnectionGUID: 7mzbjog+TL636KIKxK2VyA== X-CSE-MsgGUID: RpLqQNvZTX2I+PG++Vj5oA== X-IronPort-AV: E=McAfee;i="6800,10657,11731"; a="74835520" X-IronPort-AV: E=Sophos;i="6.23,124,1770624000"; d="scan'208";a="74835520" Received: from orviesa003.jf.intel.com ([10.64.159.143]) by fmvoesa108.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 17 Mar 2026 00:34:27 -0700 X-CSE-ConnectionGUID: l6i/QyKCQ2+Qh0zbsAMaDQ== X-CSE-MsgGUID: E2hgBnOgTvOTItdc81+GLQ== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.23,124,1770624000"; d="scan'208";a="226306582" Received: from abityuts-desk.ger.corp.intel.com (HELO localhost) ([10.245.245.97]) by ORVIESA003-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 17 Mar 2026 00:34:20 -0700 Date: Tue, 17 Mar 2026 09:34:17 +0200 From: Andy Shevchenko To: Wolfram Sang Cc: Douglas Anderson , Greg Kroah-Hartman , "Rafael J . Wysocki" , Danilo Krummrich , stable@vger.kernel.org, Andrew Lunn , Daniel Scally , "David S. Miller" , Eric Dumazet , Fabio Estevam , Frank Li , Heikki Krogerus , Heiner Kallweit , Jakub Kicinski , Len Brown , Mark Brown , Paolo Abeni , Pengutronix Kernel Team , Rob Herring , Russell King , Sakari Ailus , Saravana Kannan , Sascha Hauer , devicetree@vger.kernel.org, driver-core@lists.linux.dev, imx@lists.linux.dev, linux-acpi@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-i2c@vger.kernel.org, linux-kernel@vger.kernel.org, linux-spi@vger.kernel.org, netdev@vger.kernel.org Subject: Re: [PATCH] device property: Make modifications of fwnode "flags" thread safe Message-ID: References: <20260316154159.1.I0a4d03104ecd5103df3d76f66c8d21b1d15a2e38@changeid> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Organization: Intel Finland Oy - BIC 0357606-4 - c/o Alberga Business Park, 6 krs, Bertel Jungin Aukio 5, 02600 Espoo On Tue, Mar 17, 2026 at 08:26:53AM +0100, Wolfram Sang wrote: ... > Thanks for tackling this issue! I agree it should be fixed, just > wondered about one thing: > > > While flags are often modified while under the "fwnode_link_lock", > > this is not universally true. > > Is it a possibility to use the lock in all code paths instead? > Because... > > > struct list_head consumers; > > - u8 flags; > > + unsigned long flags; > > ... this change costs some memory on every system. Maybe it can be > avoided? How much memory does it cost? On most 64-bit architectures is +4 bytes, rarely +0 bytes, on m68k it might be +2bytes. On 32-bit it most likely +0 bytes. I expect that 64-bit machines will cope with this bump. -- With Best Regards, Andy Shevchenko