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From: David Lechner <dlechner@baylibre.com>
Date: Tue, 13 Feb 2024 13:20:31 -0600
Message-ID: <CAMknhBHc5LnaOOYoeCvtDvUcSXzPnHUtkheYMt73Uv5512dJVg@mail.gmail.com>
Subject: Re: [PATCH 1/5] spi: add spi_optimize_message() APIs
To: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Mark Brown <broonie@kernel.org>, Martin Sperl <kernel@martin.sperl.org>, 
	David Jander <david@protonic.nl>, Jonathan Cameron <jic23@kernel.org>, 
	Michael Hennerich <michael.hennerich@analog.com>, =?UTF-8?B?TnVubyBTw6E=?= <nuno.sa@analog.com>, 
	Alain Volmat <alain.volmat@foss.st.com>, Maxime Coquelin <mcoquelin.stm32@gmail.com>, 
	Alexandre Torgue <alexandre.torgue@foss.st.com>, linux-spi@vger.kernel.org, 
	linux-kernel@vger.kernel.org, linux-stm32@st-md-mailman.stormreply.com, 
	linux-arm-kernel@lists.infradead.org, linux-iio@vger.kernel.org
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On Tue, Feb 13, 2024 at 11:25=E2=80=AFAM Jonathan Cameron
<Jonathan.Cameron@huawei.com> wrote:
>
>
> I thought about suggesting splitting this into an initial patch that just=
 does
> the bits without the controller callbacks. Maybe it would work better tha=
t way
> with that introduced after the validate and splitting of transfers (so mo=
st
> of patches 1 and 2) as a patch 3 prior to the stm32 additions?

Unless anyone else feels the same way, I'm inclined to avoid the extra
work of splitting it up.


> > +static void __spi_unoptimize_message(struct spi_message *msg)
> > +{
> > +     struct spi_controller *ctlr =3D msg->spi->controller;
> > +
> > +     if (ctlr->unoptimize_message)
> > +             ctlr->unoptimize_message(msg);
> > +
> > +     msg->optimized =3D false;
> > +     msg->opt_state =3D NULL;
> > +}
>
> Seems misbalanced that this doesn't take a pre_optimized flag in but
> __spi_optimize does. I'd move handling that to outside the call in both c=
ases.
>
>

Agreed.


> > @@ -4331,10 +4463,15 @@ static int __spi_sync(struct spi_device *spi, s=
truct spi_message *message)
> >               return -ESHUTDOWN;
> >       }
> >
> > -     status =3D __spi_validate(spi, message);
> > -     if (status !=3D 0)
> > +     status =3D spi_maybe_optimize_message(spi, message);
> > +     if (status)
> >               return status;
> >
> > +     /*
> > +      * NB: all return paths after this point must ensure that
> > +      * spi_finalize_current_message() is called to avoid leaking reso=
urces.
>
> I'm not sure a catch all like that makes sense. Not sufficient to call
> the finer grained spi_maybe_unoptimize_message()  ?

Hmm... this is my bias from a previous fix showing through. Maybe this
comment doesn't belong in this patch. The short answer to your
question is "it's complicated".