Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Date:   Fri, 9 Aug 2019 20:22:17 +0200
From:   Christian Brauner <christian.brauner@ubuntu.com>
To:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc:     Hridya Valsaraju <hridya@google.com>,
        Arve =?utf-8?B?SGrDuG5uZXbDpWc=?= <arve@android.com>,
        Todd Kjos <tkjos@android.com>,
        Martijn Coenen <maco@android.com>,
        Joel Fernandes <joel@joelfernandes.org>,
        devel@driverdev.osuosl.org, linux-kernel@vger.kernel.org,
        kernel-team@android.com
Subject: Re: [PATCH v3 1/2] binder: Add default binder devices through
 binderfs when configured
Message-ID: <20190809182216.5xzx6tss6fh42mso@wittgenstein>
References: <20190808222727.132744-1-hridya@google.com>
 <20190808222727.132744-2-hridya@google.com>
 <20190809145016.GB16262@kroah.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Disposition: inline
In-Reply-To: <20190809145016.GB16262@kroah.com>
User-Agent: NeoMutt/20180716
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Fri, Aug 09, 2019 at 04:50:16PM +0200, Greg Kroah-Hartman wrote:
> On Thu, Aug 08, 2019 at 03:27:25PM -0700, Hridya Valsaraju wrote:
> > Currently, since each binderfs instance needs its own
> > private binder devices, every time a binderfs instance is
> > mounted, all the default binder devices need to be created
> > via the BINDER_CTL_ADD IOCTL.
> 
> Wasn't that a design goal of binderfs?

Sure, but if you solely rely binderfs to be used to provide binder
devices having them pre-created on each mount makes quite some sense,
imho.

> 
> > This patch aims to
> > add a solution to automatically create the default binder
> > devices for each binderfs instance that gets mounted.
> > To achieve this goal, when CONFIG_ANDROID_BINDERFS is set,
> > the default binder devices specified by CONFIG_ANDROID_BINDER_DEVICES
> > are created in each binderfs instance instead of global devices
> > being created by the binder driver.
> 
> This is going to change how things work today, what is going to break
> because of this change?
> 
> I don't object to this, except for the worry of changing the default
> behavior.

This is something that Hridya and Todd can speak better to given that
they suggested this change. :)
From my perspective, binderfs binder devices and the regular binder
driver are mostly used mutually exclusive in practice atm so that this
change has little chance of breaking anyone.

Now I really need to go back to vacation time - which I suck at
apparently. :)

Christian