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[198.145.64.163]) by smtp.gmail.com with ESMTPSA id d127sm3380122pfc.175.2020.08.26.08.13.30 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 26 Aug 2020 08:13:30 -0700 (PDT) Date: Wed, 26 Aug 2020 08:13:29 -0700 From: Kees Cook To: Dan Carpenter Cc: Allen Pais , James Bottomley , Ulf Hansson , linux-atm-general@lists.sourceforge.net, manohar.vanga@gmail.com, airlied@linux.ie, linux-hyperv@vger.kernel.org, dri-devel@lists.freedesktop.org, sre@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, linux-spi@vger.kernel.org, 3chas3@gmail.com, intel-gfx@lists.freedesktop.org, Jakub Kicinski , 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, Jens Axboe , linux-parisc@vger.kernel.org, netdev@vger.kernel.org, martyn@welchs.me.uk, dmitry.torokhov@gmail.com, linux-mmc@vger.kernel.org, Allen , linux-kernel@vger.kernel.org, alex.bou9@gmail.com, stefanr@s5r6.in-berlin.de, Daniel Vetter , linux-ntb@googlegroups.com, Romain Perier , shawnguo@kernel.org, David Miller Subject: Re: [PATCH] block: convert tasklets to use new tasklet_setup() API Message-ID: <202008260811.1CE425B5C2@keescook> References: <161b75f1-4e88-dcdf-42e8-b22504d7525c@kernel.dk> <202008171246.80287CDCA@keescook> <1597780833.3978.3.camel@HansenPartnership.com> <1597849185.3875.7.camel@HansenPartnership.com> <1597873172.4030.2.camel@HansenPartnership.com> <20200826095528.GX1793@kadam> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200826095528.GX1793@kadam> Sender: linux-hyperv-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-hyperv@vger.kernel.org On Wed, Aug 26, 2020 at 12:55:28PM +0300, Dan Carpenter wrote: > On Wed, Aug 26, 2020 at 07:21:35AM +0530, Allen Pais wrote: > > On Thu, Aug 20, 2020 at 3:09 AM James Bottomley > > wrote: > > > > > > On Wed, 2020-08-19 at 21:54 +0530, Allen wrote: > > > > > [...] > > > > > > > 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. > > > > > > > > > > Um, I thought it was exactly descriptive: you're casting to the > > > > > outer container. I thought about following the C++ dynamic casting > > > > > style, so out_cast(), but that seemed a bit pejorative. What about > > > > > outer_cast()? > > > > > > > > > > > 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. > > > > > > > > > > I'm not opposed to container_from() but it seems a little less > > > > > descriptive than outer_cast() but I don't really care. I always > > > > > have to look up container_of() when I'm using it so this would just > > > > > be another macro of that type ... > > > > > > > > > > > > > So far we have a few which have been suggested as replacement > > > > for from_tasklet() > > > > > > > > - out_cast() or outer_cast() > > > > - from_member(). > > > > - container_from() or from_container() > > > > > > > > from_container() sounds fine, would trimming it a bit work? like > > > > from_cont(). > > > > > > I'm fine with container_from(). It's the same form as container_of() > > > and I think we need urgent agreement to not stall everything else so > > > the most innocuous name is likely to get the widest acceptance. > > > > Kees, > > > > Will you be sending the newly proposed API to Linus? I have V2 > > which uses container_from() > > ready to be sent out. > > I liked that James swapped the first two arguments so that it matches > container_of(). Plus it's nice that when you have: > > struct whatever *foo = container_from(ptr, foo, member); > > Then it means that "ptr == &foo->member". I'm a bit stalled right now -- the merge window was keeping me busy, and this week is the Linux Plumbers Conference. This is on my list, but I haven't gotten back around to it. If you want, feel free to send the container_from() patch; you might be able to unblock this faster than me right now. :) -Kees -- Kees Cook