linux-kernel - Re: [PATCH v2 04/15] spi: Replace open coded spi_controller_xfer

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Message-ID: <dafdb3d9-572f-49d3-82d7-f0d7667df5dd@sirena.org.uk>
Date:   Tue, 11 Jul 2023 16:49:54 +0100
From:   Mark Brown <broonie@...nel.org>
To:     Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Cc:     Cristian Ciocaltea <cristian.ciocaltea@...labora.com>,
        Yang Yingliang <yangyingliang@...wei.com>,
        Amit Kumar Mahapatra via Alsa-devel 
        <alsa-devel@...a-project.org>,
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        Tharun Kumar P <tharunkumar.pasumarthi@...rochip.com>,
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        Uwe Kleine-König 
        <u.kleine-koenig@...gutronix.de>, linux-spi@...r.kernel.org,
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Subject: Re: [PATCH v2 04/15] spi: Replace open coded
 spi_controller_xfer_timeout()

On Tue, Jul 11, 2023 at 06:30:06PM +0300, Andy Shevchenko wrote:
> On Tue, Jul 11, 2023 at 03:14:54PM +0100, Mark Brown wrote:

> > Like I say we *should* be fine with the refactoring without this, or at
> > least if it's an issue we should improve the validation.

> For the speeds < 1000 Hz, this change will lead to the div by 0 crash.
> It seems that the current code which this one removes is better than
> the spi_controller_xfer_timeout() provides.

> If anything, the spi_controller_xfer_timeout() should be improved first.
> So, for now I drop this for sure. Maybe in the future we can come back
> to it.

I don't think this is the only thing that might fall over without a
speed, what we've generally been doing (and do try to do with speeds, we
already need to default in the controller's speed and so on) is to
sanitise input on the way into the subsystem rather than trying to
ensure that all the users are handling everything.

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