2022-05-15 14:24:30

by Krzysztof Kozlowski

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

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 <[email protected]>
> Signed-off-by: Anand Moon <[email protected]>
> ---
> 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

2022-05-18 04:48:22

by Anand Moon

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

Hi Krzysztof,

On Sun, 15 May 2022 at 15:13, Krzysztof Kozlowski
<[email protected]> wrote:
>
> 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 <[email protected]>
> > Signed-off-by: Anand Moon <[email protected]>
> > ---
> > 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?

Thanks for your review comments
Yes have tested the changes, this was last-minute changes
will drop this in the next version.

>
> Best regards,
> Krzysztof

Thanks & Regards


-Anand