From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pj1-x1042.google.com ([2607:f8b0:4864:20::1042]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1k8NiB-0001o7-Kk for linux-um@lists.infradead.org; Wed, 19 Aug 2020 13:01:04 +0000 Received: by mail-pj1-x1042.google.com with SMTP id c10so1140168pjn.1 for ; Wed, 19 Aug 2020 06:01:00 -0700 (PDT) Subject: Re: [PATCH] block: convert tasklets to use new tasklet_setup() API 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> From: Jens Axboe Message-ID: Date: Wed, 19 Aug 2020 07:00:53 -0600 MIME-Version: 1.0 In-Reply-To: <1597780833.3978.3.camel@HansenPartnership.com> Content-Language: en-US List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-um" Errors-To: linux-um-bounces+geert=linux-m68k.org@lists.infradead.org To: James Bottomley , Kees Cook Cc: 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, kys@microsoft.com, 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 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. 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. -- Jens Axboe _______________________________________________ linux-um mailing list linux-um@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-um