linux-kernel - Re: [PATCH] regulator: core: fix error path for regulator_set_voltage

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Date:   Mon, 18 Mar 2019 19:03:19 +0300
From:   Dmitry Osipenko <digetx@...il.com>
To:     Steve Twiss <stwiss.opensource@...semi.com>,
        Liam Girdwood <lgirdwood@...il.com>,
        Mark Brown <broonie@...nel.org>
Cc:     LKML <linux-kernel@...r.kernel.org>,
        Maciej Purski <m.purski@...subg.com>,
        Support Opensource <support.opensource@...semi.com>
Subject: Re: [PATCH] regulator: core: fix error path for
 regulator_set_voltage_unlocked

18.03.2019 18:32, Steve Twiss пишет:
> During several error paths in the function
> regulator_set_voltage_unlocked() the value of 'ret' can take on negative
> error values. However, in calls that go through the 'goto out' statement,
> this return value is lost and return 0 is used instead, indicating a
> 'pass'.
> 
> There are several cases where this function should legitimately return a
> fail instead of a pass: one such case includes constraints check during
> voltage selection in the call to regulator_check_voltage(), which can
> have -EINVAL for the case when an unsupported voltage is incorrectly
> requested. In that case, -22 is expected as the return value, not 0.
> 
> Fixes: 9243a195be7a ("regulator: core: Change voltage setting path")
> Signed-off-by: Steve Twiss <stwiss.opensource@...semi.com>
> ---
>  drivers/regulator/core.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
> index 68473d0..caf8743 100644
> --- a/drivers/regulator/core.c
> +++ b/drivers/regulator/core.c
> @@ -3326,7 +3326,7 @@ static int regulator_set_voltage_unlocked(struct regulator *regulator,
>  		goto out2;
>  
>  out:
> -	return 0;
> +	return ret;
>  out2:
>  	voltage->min_uV = old_min_uV;
>  	voltage->max_uV = old_max_uV;
> 

Looks like a good catch.

Probably will be a bit better to write this as:

        /* for not coupled regulators this will just set the voltage */
        ret = regulator_balance_voltage(rdev, state);
-       if (ret < 0)
-               goto out2;
-
+       if (ret < 0) {
+               voltage->min_uV = old_min_uV;
+               voltage->max_uV = old_max_uV;
+       }
 out:
-       return 0;
-out2:
-       voltage->min_uV = old_min_uV;
-       voltage->max_uV = old_max_uV;
-
        return ret;
 }