linux-kernel - Re: [PATCH] Regulator: Suppress compiler warnings

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Date:	Tue, 1 Sep 2015 09:52:13 +0900
From:	Krzysztof Kozlowski <k.kozlowski@...sung.com>
To:	Keith Busch <keith.busch@...el.com>
Cc:	linux-kernel@...r.kernel.org, Liam Girdwood <lgirdwood@...il.com>,
	Mark Brown <broonie@...nel.org>
Subject: Re: [PATCH] Regulator: Suppress compiler warnings

2015-09-01 1:41 GMT+09:00 Keith Busch <keith.busch@...el.com>:
> Some compilers complain of possible uninitialized variable usage, like
> the following:
>
>   drivers/regulator/helpers.c: In function ‘regulator_get_bypass_regmap’:
>   drivers/regulator/helpers.c:463:16: warning: ‘val’ may be used uninitialized in this function [-Wuninitialized]
>
> The code is safe though, and only uses the variables if they were
> successfully set, so suppressing the warning with uninitialized_val.
>
> Signed-off-by: Keith Busch <keith.busch@...el.com>
> ---
>  drivers/regulator/helpers.c |    6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/regulator/helpers.c b/drivers/regulator/helpers.c
> index 3bbb326..bb5b22a 100644
> --- a/drivers/regulator/helpers.c
> +++ b/drivers/regulator/helpers.c
> @@ -30,7 +30,7 @@
>   */
>  int regulator_is_enabled_regmap(struct regulator_dev *rdev)
>  {
> -       unsigned int val;
> +       unsigned int uninitialized_var(val);
>         int ret;
>
>         ret = regmap_read(rdev->regmap, rdev->desc->enable_reg, &val);

This is quite common pattern so such work-around should be added to
many other functions leading to code obfuscation. Which compiler do
you have in mind?

Best regards,
Krzysztof

> @@ -114,7 +114,7 @@ EXPORT_SYMBOL_GPL(regulator_disable_regmap);
>   */
>  int regulator_get_voltage_sel_regmap(struct regulator_dev *rdev)
>  {
> -       unsigned int val;
> +       unsigned int uninitialized_var(val);
>         int ret;
>
>         ret = regmap_read(rdev->regmap, rdev->desc->vsel_reg, &val);
> @@ -453,7 +453,7 @@ EXPORT_SYMBOL_GPL(regulator_set_bypass_regmap);
>   */
>  int regulator_get_bypass_regmap(struct regulator_dev *rdev, bool *enable)
>  {
> -       unsigned int val;
> +       unsigned int uninitialized_var(val);
>         int ret;
>
>         ret = regmap_read(rdev->regmap, rdev->desc->bypass_reg, &val);
> --
> 1.7.10.4
>
> --
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