Re: [PATCH 3/4] dmaengine: ste_dma40: Remove unneeded ERROR and NULL check in ste_dma40

[Jiabing Wan]

On 2022/5/18 15:15, Krzysztof Kozlowski wrote:
> On 16/05/2022 10:41, Wan Jiabing wrote:
> > clk_put() already checks ERROR by using IS_ERR.
> > clk_disable_unprepare() already checks NULL by using IS_ERR_OR_NULL.
> > Remove unneeded NULL check for clk_ret and ERROR check for clk.
> >
> > Signed-off-by: Wan Jiabing <wanjiabing@xxxxxxxx>
> > ---
> >   drivers/dma/ste_dma40.c | 10 ++++------
> >   1 file changed, 4 insertions(+), 6 deletions(-)
> >
> > diff --git a/drivers/dma/ste_dma40.c b/drivers/dma/ste_dma40.c
> > index e1827393143f..7d1bf4ae4495 100644
> > --- a/drivers/dma/ste_dma40.c
> > +++ b/drivers/dma/ste_dma40.c
> > @@ -3119,7 +3119,7 @@ static struct d40_base * __init d40_hw_detect_init(struct platform_device *pdev)
> >   	clk = clk_get(&pdev->dev, NULL);
> >   	if (IS_ERR(clk)) {
> >   		d40_err(&pdev->dev, "No matching clock found\n");
> > -		goto check_prepare_enabled;
> > +		goto disable_unprepare;
> This should be rather return PTR_ERR. No need to jump to labels which
> are not relevant (even if harmless) for this case. It's a confusing code.
OK, I'll fix it.
> >   	}
> >   
> >   	clk_ret = clk_prepare_enable(clk);
> > @@ -3305,12 +3305,10 @@ static struct d40_base * __init d40_hw_detect_init(struct platform_device *pdev)
> >   	iounmap(virtbase);
> >    release_region:
> >   	release_mem_region(res->start, resource_size(res));
> > - check_prepare_enabled:
> > -	if (!clk_ret)
> >    disable_unprepare:
> > -		clk_disable_unprepare(clk);
> > -	if (!IS_ERR(clk))
> > -		clk_put(clk);

So this IS_ERR(clk) is also better than WARN_ON_ONCE(IS_ERR(clk)) in 
clk_put().

IS_ERR(clk) before  clk_put(clk) is needed for avoiding the unexpected warning.

> > +	clk_disable_unprepare(clk);
> > +	clk_put(clk);
> > +
> >   	return NULL;
> >   }
> >   
Thanks,
Wan Jiabing