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 alsa0.perex.cz (alsa0.perex.cz [77.48.224.243]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 380E6C4332F for ; Sat, 26 Nov 2022 08:14:43 +0000 (UTC) Received: from alsa1.perex.cz (alsa1.perex.cz [207.180.221.201]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by alsa0.perex.cz (Postfix) with ESMTPS id 63BC518D4; Sat, 26 Nov 2022 09:13:51 +0100 (CET) DKIM-Filter: OpenDKIM Filter v2.11.0 alsa0.perex.cz 63BC518D4 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=alsa-project.org; s=default; t=1669450481; bh=imibZHjJL9cpBpAGiGFcUllw5xFRNIsDuHu6Y+fwag4=; h=Date:From:To:Subject:References:In-Reply-To:Cc:List-Id: List-Unsubscribe:List-Archive:List-Post:List-Help:List-Subscribe: From; b=JK+lYxZGSvNgSB/6qM6Z63q2CS+PHILXJTADr0EJju3Iouap/Y3K4RG+knpAngdfr sSVaFdH+I0FNRaG9r0y5sqM2GwUsec0+68++D4Q6PrErHxpvTiWaayazct9b7sUbSR +BV6ySMIMzMiogJAeU2zYF9A+XZSYltjt6n1oEUo= Received: from alsa1.perex.cz (localhost.localdomain [127.0.0.1]) by alsa1.perex.cz (Postfix) with ESMTP id A9128F80718; Sat, 26 Nov 2022 08:59:31 +0100 (CET) Received: by alsa1.perex.cz (Postfix, from userid 50401) id 8D6AFF8025D; Wed, 23 Nov 2022 20:06:27 +0100 (CET) Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by alsa1.perex.cz (Postfix) with ESMTPS id 4042EF800BB for ; Wed, 23 Nov 2022 20:06:24 +0100 (CET) DKIM-Filter: OpenDKIM Filter v2.11.0 alsa1.perex.cz 4042EF800BB Authentication-Results: alsa1.perex.cz; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="V2GZdWHP" Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 16BBFB82405; Wed, 23 Nov 2022 19:06:24 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id D7968C433D6; Wed, 23 Nov 2022 19:06:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1669230382; bh=imibZHjJL9cpBpAGiGFcUllw5xFRNIsDuHu6Y+fwag4=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=V2GZdWHPvr+u9NV42kW3apisS1jk4Cp6h19MZ6qfaWIUGIVJV5gV2ha39zpYgwqP7 WIt60wd9b8FvKniDUGYZZUiLCvZQFxPf+YdmrcSFnI46/b/EWX33zlFDz2TQxA125f 2aOS9p5Y/Iiz28acyMaujccSu8U/Ol2yQw6Symkw= Date: Wed, 23 Nov 2022 20:06:20 +0100 From: Greg Kroah-Hartman To: Jason Gunthorpe Subject: Re: [PATCH 3/5] driver core: make struct device_type.uevent() take a const * Message-ID: References: <97be39ed-3cea-d55a-caa6-c2652baef399@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Mailman-Approved-At: Sat, 26 Nov 2022 08:58:53 +0100 Cc: Alexandre Belloni , Heikki Krogerus , Sean Young , "Rafael J. Wysocki" , alsa-devel@alsa-project.org, platform-driver-x86@vger.kernel.org, linux-i2c@vger.kernel.org, Andreas Noever , linux-i3c@lists.infradead.org, linux1394-devel@lists.sourceforge.net, Frank Rowand , Dan Williams , Andy Shevchenko , Bard Liao , Pierre-Louis Bossart , Matthew Wilcox , linux-acpi@vger.kernel.org, Alan Stern , linux-serial@vger.kernel.org, linux-input@vger.kernel.org, Won Chung , Len Brown , devicetree@vger.kernel.org, Chaitanya Kulkarni , Ira Weiny , Michael Jamet , Ming Lei , Mark Gross , Hans de Goede , Rob Herring , Jiri Slaby , Thomas Gleixner , Mauro Carvalho Chehab , Mika Westerberg , Jens Axboe , linux-block@vger.kernel.org, Jilin Yuan , "Martin K. Petersen" , Dmitry Torokhov , linux-kernel@vger.kernel.org, Wolfram Sang , Vinod Koul , Stefan Richter , Sakari Ailus , Yehezkel Bernat , Sanyog Kale , linux-media@vger.kernel.org, Maximilian Luz , linux-usb@vger.kernel.org X-BeenThere: alsa-devel@alsa-project.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: "Alsa-devel mailing list for ALSA developers - http://www.alsa-project.org" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: alsa-devel-bounces@alsa-project.org Sender: "Alsa-devel" On Wed, Nov 23, 2022 at 02:25:59PM -0400, Jason Gunthorpe wrote: > On Wed, Nov 23, 2022 at 07:10:49PM +0100, Greg Kroah-Hartman wrote: > > On Wed, Nov 23, 2022 at 05:49:36PM +0000, Matthew Wilcox wrote: > > > On Wed, Nov 23, 2022 at 01:29:56PM -0400, Jason Gunthorpe wrote: > > > > #define generic_container_of(in_type, in, out_type, out_member) \ > > > > _Generic(in, \ > > > > const in_type *: ((const out_type *)container_of(in, out_type, out_member)), \ > > > > in_type *: ((out_type *)container_of(in, out_type, out_member)) \ > > > > ) > > > > > > There's a neat trick I found in seqlock.h: > > > > > > #define generic_container_of(in_t, in, out_t, m) \ > > > _Generic(*(in), \ > > > const in_t: ((const out_t *)container_of(in, out_t, m)), \ > > > in_t: ((out_t *)container_of(in, out_type, m)) \ > > > ) > > > > > > and now it fits in 80 columns ;-) > > > > Nice trick! Dropping the inline functions is a bit different, let me > > see if that still gives a sane error if we pass an incorrect type or > > mess with the const * the wrong way. I'll run some tests tomorrow > > afternoon... > > The errors in some cases are very verbose, but it is somewhat > understandable - the worst is when _Generic fails to match anything, > but also at least clang partially expanded container_of and it throws > other assertions too. > > I also wonder if this could just be rolled into the normal > container_of. I think we might be able to now, my previous attempts with inline functions prevented that. I'll beat on that tomorrow... > in_type would have to be derived like: > > in_type = typeof((out_type *)NULL)->out_member) > > But I don't know if you can use typeof in a generic type matching expression.. Maybe that is what threw me before, I can't remember. I do know we tried a number of different attempts, can't recall the failed ones... thanks, greg k-h