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From:   Bartosz Golaszewski <bgolaszewski@baylibre.com>
Date:   Thu, 20 May 2021 16:39:50 +0200
Message-ID: <CAMpxmJVy12at1+37iPiqTXe6mvodUpjDKCkFQO02Cu=u5_sp_A@mail.gmail.com>
Subject: Re: [PATCH v1 1/2] gpiolib: Never return internal error codes to user space
To:     Andy Shevchenko <andy.shevchenko@gmail.com>
Cc:     Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
        Kent Gibson <warthog618@gmail.com>,
        linux-gpio <linux-gpio@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Linus Walleij <linus.walleij@linaro.org>,
        Suresh Balakrishnan <suresh.balakrishnan@intel.com>
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On Thu, May 20, 2021 at 3:15 PM Andy Shevchenko
<andy.shevchenko@gmail.com> wrote:
>
> On Thu, May 20, 2021 at 4:08 PM Bartosz Golaszewski
> <bgolaszewski@baylibre.com> wrote:
> > On Wed, May 19, 2021 at 10:30 AM Andy Shevchenko
> > <andriy.shevchenko@linux.intel.com> wrote:
> > > On Wed, May 19, 2021 at 04:04:34PM +0800, Kent Gibson wrote:
> > > > On Wed, May 19, 2021 at 10:45:16AM +0300, Andy Shevchenko wrote:
> > > > > On Wed, May 19, 2021 at 07:24:51AM +0800, Kent Gibson wrote:
> > > > > > On Tue, May 18, 2021 at 06:50:12PM +0300, Andy Shevchenko wrote:
>
> ...
>
> > > > > > > Fixes: d7c51b47ac11 ("gpio: userspace ABI for reading/writing GPIO lines")
> > > > > > > Fixes: 61f922db7221 ("gpio: userspace ABI for reading GPIO line events")
> > > > > > > Fixes: 3c0d9c635ae2 ("gpiolib: cdev: support GPIO_V2_GET_LINE_IOCTL and GPIO_V2_LINE_GET_VALUES_IOCTL")
>
> ...
>
> > > > > > You immediately revert this patch in patch 2.
> > > > > > My understanding is that is not allowed within a patch set.
> > > > >
> > > > > > Why split the patches instead of going direct to the new helper?
> > > > >
> > > > > It's for backporting to make it easier. (I deliberately left the context above)
> > > > >
> > > > > I can fold them if maintainers think it's okay to do.
> > > > >
> > > >
> > > > Not sure what the constraints are on backporting, but wouldn't it be
> > > > simpler and cleaner to backport the new helper?
> > >
> > > Logically (and ideally) it would be three different patches:
> > >  1) introduce helper
> > >  2) use helper
> > >  3) fix places where it's needed to be done
> > >
> > > But the above scheme doesn't fit backporting idea (we don't backport new
> > > features and APIs without really necessity). So, the options left are:
> > >
> > > Option a: One patch (feels a bit like above)
> > > Option b: Two patches like in this series (yes, you are correct about
> > >           disadvantages)
> > >
> > > > But, as you say, it is the maintainers' call.
>
> > Third option is to backport this patch but apply the helper
> > immediately to master.
>
> If I got you correctly, you want to have two patches, one for
> backporting and one for current, correct? But how can we backport
> something which has never been upstreamed?
>

Well we would not technically backport anything - there would be one
patch for mainline and a separate fix for stable.

Bart