Re: [PATCHv2 3/6] thermal: exynos: Check before clk_disable_unprepare() not needed

[Krzysztof Kozlowski]

On 15/05/2022 08:41, Anand Moon wrote:
> All code in clk_disable_unprepare() already checks the clk ptr using
> IS_ERR_OR_NULL so there is no need to check it again before calling it.
> A lot of other drivers already rely on this behaviour, so it's safe
> to do so here.
> 
> Cc: Bartlomiej Zolnierkiewicz <bzolnier@xxxxxxxxx>
> Signed-off-by: Anand Moon <linux.amoon@xxxxxxxxx>
> ---
> v1: improve the commit message
> ---
>  drivers/thermal/samsung/exynos_tmu.c | 12 ++++--------
>  1 file changed, 4 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/thermal/samsung/exynos_tmu.c b/drivers/thermal/samsung/exynos_tmu.c
> index 1ef90dc52c08..58ff1b577c47 100644
> --- a/drivers/thermal/samsung/exynos_tmu.c
> +++ b/drivers/thermal/samsung/exynos_tmu.c
> @@ -289,8 +289,7 @@ static int exynos_tmu_initialize(struct platform_device *pdev)
>  
>  	mutex_lock(&data->lock);
>  	clk_enable(data->clk);
> -	if (!IS_ERR(data->clk_sec))
> -		clk_enable(data->clk_sec);
> +	clk_enable(data->clk_sec);

You say that clk_enable() checks for IS_ERR_OR_NULL. Where? I see only
check for non-null case and then immediately taking clk prepare lock.

This looks buggy... did you test it?

Best regards,
Krzysztof