Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Date:   Mon, 17 Aug 2020 12:48:34 -0700
From:   Kees Cook <keescook@chromium.org>
To:     Jens Axboe <axboe@kernel.dk>
Cc:     Allen Pais <allen.cryptic@gmail.com>, 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, James.Bottomley@HansenPartnership.com,
        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 <allen.lkml@gmail.com>,
        Romain Perier <romain.perier@gmail.com>
Subject: Re: [PATCH] block: convert tasklets to use new tasklet_setup() API
Message-ID: <202008171246.80287CDCA@keescook>
References: <20200817091617.28119-1-allen.cryptic@gmail.com>
 <20200817091617.28119-2-allen.cryptic@gmail.com>
 <b5508ca4-0641-7265-2939-5f03cbfab2e2@kernel.dk>
 <202008171228.29E6B3BB@keescook>
 <161b75f1-4e88-dcdf-42e8-b22504d7525c@kernel.dk>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <161b75f1-4e88-dcdf-42e8-b22504d7525c@kernel.dk>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

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 <allen.lkml@gmail.com>
> >>>
> >>> 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
changes end up getting whole-release delays because of the need to have
the API in place for everyone before patches to do the changes can be
sent to multiple maintainers, etc.

-- 
Kees Cook