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[198.145.64.163]) by smtp.gmail.com with ESMTPSA id t25sm26530806pfl.198.2020.08.18.13.10.15 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 18 Aug 2020 13:10:15 -0700 (PDT) Date: Tue, 18 Aug 2020 13:10:14 -0700 From: Kees Cook To: James Bottomley Cc: Jens Axboe , Allen Pais , jdike@addtoit.com, richard@nod.at, anton.ivanov@cambridgegreys.com, 3chas3@gmail.com, stefanr@s5r6.in-berlin.de, airlied@linux.ie, daniel@ffwll.ch, sre@kernel.org, kys@microsoft.com, deller@gmx.de, dmitry.torokhov@gmail.com, jassisinghbrar@gmail.com, shawnguo@kernel.org, s.hauer@pengutronix.de, maximlevitsky@gmail.com, oakad@yahoo.com, ulf.hansson@linaro.org, mporter@kernel.crashing.org, alex.bou9@gmail.com, broonie@kernel.org, martyn@welchs.me.uk, manohar.vanga@gmail.com, mitch@sfgoth.com, davem@davemloft.net, kuba@kernel.org, linux-um@lists.infradead.org, linux-kernel@vger.kernel.org, linux-atm-general@lists.sourceforge.net, netdev@vger.kernel.org, linux-block@vger.kernel.org, linux-arm-kernel@lists.infradead.org, openipmi-developer@lists.sourceforge.net, linux1394-devel@lists.sourceforge.net, intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, linux-hyperv@vger.kernel.org, linux-parisc@vger.kernel.org, linux-input@vger.kernel.org, linux-mmc@vger.kernel.org, linux-ntb@googlegroups.com, linux-s390@vger.kernel.org, linux-spi@vger.kernel.org, devel@driverdev.osuosl.org, Allen Pais , Romain Perier Subject: Re: [PATCH] block: convert tasklets to use new tasklet_setup() API Message-ID: <202008181309.FD3940A2D5@keescook> 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: <1597780833.3978.3.camel@HansenPartnership.com> Sender: linux-hyperv-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-hyperv@vger.kernel.org On Tue, Aug 18, 2020 at 01:00:33PM -0700, 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. I like this! Shall I send this to Linus to see if this can land in -rc2 for use going forward? -- Kees Cook