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=-3.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=no 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 D2AAFC433DF for ; Wed, 19 Aug 2020 13:11:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A6740206FA for ; Wed, 19 Aug 2020 13:11:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1597842710; bh=vxq1i+5+rO8RGMcDRwl1Kl6llTi6GXYX5kfyPA4jblo=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=Tx0Fa7I+ZkG8KFu1UWuyJr1TjvhV+TJd5LKDUPdqU+ly9dJjeqGMK71WubvUTyHE3 vzf78yUlJBTryHlCYASDW6mcXmleyumZWCsCCta7Jd5du0eHsz9GtHLfeajBfHKyun 9MpdEQcyKqQFpcJM32cyHXS9ged2jroWVBQNFmGA= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728358AbgHSNLq (ORCPT ); Wed, 19 Aug 2020 09:11:46 -0400 Received: from mail.kernel.org ([198.145.29.99]:56402 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728149AbgHSNLh (ORCPT ); Wed, 19 Aug 2020 09:11:37 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 6BC432065F; Wed, 19 Aug 2020 13:11:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1597842695; bh=vxq1i+5+rO8RGMcDRwl1Kl6llTi6GXYX5kfyPA4jblo=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=skOvnyoi/s8DCceKzmupkt1jYOaWtFdAAqlQ/MFXOrVpqmMQl+hsMEEjs4HBhOLQu 0c0ztyi4uXIKad6aYvYHUv3AbWF2jtioPUcwcQoAVMj74KG+/FMhByNjrec9UmAV0D o/Yb0Ae9Hr3NDLzjtRMcTZ4PqnDnfMAucqQAMsmk= Date: Wed, 19 Aug 2020 15:11:58 +0200 From: Greg KH To: Jens Axboe Cc: James Bottomley , Kees Cook , ulf.hansson@linaro.org, linux-atm-general@lists.sourceforge.net, manohar.vanga@gmail.com, airlied@linux.ie, Allen Pais , linux-hyperv@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, anton.ivanov@cambridgegreys.com, devel@driverdev.osuosl.org, linux-s390@vger.kernel.org, linux1394-devel@lists.sourceforge.net, maximlevitsky@gmail.com, richard@nod.at, deller@gmx.de, jassisinghbrar@gmail.com, 3chas3@gmail.com, intel-gfx@lists.freedesktop.org, kuba@kernel.org, mporter@kernel.crashing.org, jdike@addtoit.com, oakad@yahoo.com, s.hauer@pengutronix.de, linux-input@vger.kernel.org, linux-um@lists.infradead.org, linux-block@vger.kernel.org, broonie@kernel.org, openipmi-developer@lists.sourceforge.net, mitch@sfgoth.com, linux-arm-kernel@lists.infradead.org, linux-parisc@vger.kernel.org, netdev@vger.kernel.org, martyn@welchs.me.uk, dmitry.torokhov@gmail.com, linux-mmc@vger.kernel.org, sre@kernel.org, linux-spi@vger.kernel.org, alex.bou9@gmail.com, Allen Pais , stefanr@s5r6.in-berlin.de, daniel@ffwll.ch, linux-ntb@googlegroups.com, Romain Perier , shawnguo@kernel.org, davem@davemloft.net Subject: Re: [PATCH] block: convert tasklets to use new tasklet_setup() API Message-ID: <20200819131158.GA2591006@kroah.com> References: <20200817091617.28119-1-allen.cryptic@gmail.com> <20200817091617.28119-2-allen.cryptic@gmail.com> <202008171228.29E6B3BB@keescook> <161b75f1-4e88-dcdf-42e8-b22504d7525c@kernel.dk> <202008171246.80287CDCA@keescook> <1597780833.3978.3.camel@HansenPartnership.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Aug 19, 2020 at 07:00:53AM -0600, Jens Axboe wrote: > On 8/18/20 1:00 PM, James Bottomley wrote: > > On Mon, 2020-08-17 at 13:02 -0700, Jens Axboe wrote: > >> On 8/17/20 12:48 PM, Kees Cook wrote: > >>> On Mon, Aug 17, 2020 at 12:44:34PM -0700, Jens Axboe wrote: > >>>> On 8/17/20 12:29 PM, Kees Cook wrote: > >>>>> On Mon, Aug 17, 2020 at 06:56:47AM -0700, Jens Axboe wrote: > >>>>>> On 8/17/20 2:15 AM, Allen Pais wrote: > >>>>>>> From: Allen Pais > >>>>>>> > >>>>>>> In preparation for unconditionally passing the > >>>>>>> struct tasklet_struct pointer to all tasklet > >>>>>>> callbacks, switch to using the new tasklet_setup() > >>>>>>> and from_tasklet() to pass the tasklet pointer explicitly. > >>>>>> > >>>>>> Who came up with the idea to add a macro 'from_tasklet' that > >>>>>> is just container_of? container_of in the code would be > >>>>>> _much_ more readable, and not leave anyone guessing wtf > >>>>>> from_tasklet is doing. > >>>>>> > >>>>>> I'd fix that up now before everything else goes in... > >>>>> > >>>>> As I mentioned in the other thread, I think this makes things > >>>>> much more readable. It's the same thing that the timer_struct > >>>>> conversion did (added a container_of wrapper) to avoid the > >>>>> ever-repeating use of typeof(), long lines, etc. > >>>> > >>>> But then it should use a generic name, instead of each sub-system > >>>> using some random name that makes people look up exactly what it > >>>> does. I'm not huge fan of the container_of() redundancy, but > >>>> adding private variants of this doesn't seem like the best way > >>>> forward. Let's have a generic helper that does this, and use it > >>>> everywhere. > >>> > >>> I'm open to suggestions, but as things stand, these kinds of > >>> treewide > >> > >> On naming? Implementation is just as it stands, from_tasklet() is > >> totally generic which is why I objected to it. from_member()? Not > >> great with naming... But I can see this going further and then we'll > >> suddenly have tons of these. It's not good for readability. > > > > Since both threads seem to have petered out, let me suggest in > > kernel.h: > > > > #define cast_out(ptr, container, member) \ > > container_of(ptr, typeof(*container), member) > > > > It does what you want, the argument order is the same as container_of > > with the only difference being you name the containing structure > > instead of having to specify its type. > > Not to incessantly bike shed on the naming, but I don't like cast_out, > it's not very descriptive. And it has connotations of getting rid of > something, which isn't really true. I agree, if we want to bike shed, I don't like this color either. > FWIW, I like the from_ part of the original naming, as it has some clues > as to what is being done here. Why not just from_container()? That > should immediately tell people what it does without having to look up > the implementation, even before this becomes a part of the accepted > coding norm. Why are people hating on the well-known and used container_of()? If you really hate to type the type and want a new macro, what about 'container_from()'? (noun/verb is nicer to sort symbols by...) But really, why is this even needed? thanks, greg k-h