linux-kernel - Re: [PATCH v7 27/34] i2c: tegra: Check errors for both positive and negative values

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Date:   Thu, 17 Sep 2020 14:09:55 +0200
From:   Thierry Reding <thierry.reding@...il.com>
To:     Dmitry Osipenko <digetx@...il.com>
Cc:     Jonathan Hunter <jonathanh@...dia.com>,
        Laxman Dewangan <ldewangan@...dia.com>,
        Wolfram Sang <wsa@...-dreams.de>,
        Michał Mirosław <mirq-linux@...e.qmqm.pl>,
        Andy Shevchenko <andy.shevchenko@...il.com>,
        linux-i2c@...r.kernel.org, linux-tegra@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v7 27/34] i2c: tegra: Check errors for both positive and
 negative values

On Wed, Sep 09, 2020 at 01:39:59AM +0300, Dmitry Osipenko wrote:
> The driver's code is inconsistent in regards to the error values checking.
> The correct way should be to check both positive and negative values.
> This patch cleans up the error-checks in the code. Note that the
> pm_runtime_get_sync() could return positive value on success, hence only
> relevant parts of the code are changed by this patch.
> 
> Reviewed-by: Michał Mirosław <mirq-linux@...e.qmqm.pl>
> Signed-off-by: Dmitry Osipenko <digetx@...il.com>
> ---
>  drivers/i2c/busses/i2c-tegra.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)

Why? All of these functions "return 0 on success or a negative error
code on failure", don't they?

I would actually argue that all of the other checks are wrong. As you
mention yourself, some functions may decide to return positive values on
success to convey some extra information, so making this just check for
non-zero carries a risk of its own.

Thierry

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