[PATCH 0/4] dmaengine: Remove unneeded ERROR checks before clk_xxx

[PATCH 0/4] dmaengine: Remove unneeded ERROR checks before clk_xxx

[Wan Jiabing]

This patch set tries to remove unneeded ERROR check before clk_xxx.
clk_put() already uses !clk and IS_ERR(clk) to check ERROR or NULL.
clk_disable_unprepare() already checks ERROR by using IS_ERR_OR_NULL.

Remove unneeded ERROR or NULL check before them.

Wan Jiabing (4):
  dmaengine: ep93xx_dma: Remove unneeded ERROR check before clk_put
  dmaengine: sprd-dma: Remove unneeded ERROR check before clk_disable_unprepare
  dmaengine: ste_dma40: Remove unneeded ERROR and NULL check in ste_dma40
  dmaengine: xgene-dma: Remove unneeded ERROR check before clk_disable_unprepare

 drivers/dma/ep93xx_dma.c |  3 +--
 drivers/dma/sprd-dma.c   |  7 +------
 drivers/dma/ste_dma40.c  | 10 ++++------
 drivers/dma/xgene-dma.c  |  6 ++----
 4 files changed, 8 insertions(+), 18 deletions(-)

-- 
2.36.1

[PATCH 1/4] dmaengine: ep93xx_dma: Remove unneeded ERROR check before clk_put

[Wan Jiabing]

clk_put() already uses !clk and IS_ERR(clk) to check ERROR or NULL.
Remove unneeded ERROR or NULL check for edmac->clk.

Signed-off-by: Wan Jiabing <wanjiabing@vivo.com>
---
 drivers/dma/ep93xx_dma.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/dma/ep93xx_dma.c b/drivers/dma/ep93xx_dma.c
index 971ff5f9ae84..60dc7b3f3d0d 100644
--- a/drivers/dma/ep93xx_dma.c
+++ b/drivers/dma/ep93xx_dma.c
@@ -1398,8 +1398,7 @@ static int __init ep93xx_dma_probe(struct platform_device *pdev)
 	if (unlikely(ret)) {
 		for (i = 0; i < edma->num_channels; i++) {
 			struct ep93xx_dma_chan *edmac = &edma->channels[i];
-			if (!IS_ERR_OR_NULL(edmac->clk))
-				clk_put(edmac->clk);
+			clk_put(edmac->clk);
 		}
 		kfree(edma);
 	} else {
-- 
2.36.1

[PATCH 2/4] dmaengine: sprd-dma: Remove unneeded ERROR check before clk_disable_unprepare

[Wan Jiabing]

clk_disable_unprepare() already checks ERROR by using IS_ERR_OR_NULL.
Remove unneeded ERROR check for sdev->ashb_clk.

Signed-off-by: Wan Jiabing <wanjiabing@vivo.com>
---
 drivers/dma/sprd-dma.c | 7 +------
 1 file changed, 1 insertion(+), 6 deletions(-)

diff --git a/drivers/dma/sprd-dma.c b/drivers/dma/sprd-dma.c
index 7f158ef5672d..bf5ad879b5e2 100644
--- a/drivers/dma/sprd-dma.c
+++ b/drivers/dma/sprd-dma.c
@@ -279,12 +279,7 @@ static int sprd_dma_enable(struct sprd_dma_dev *sdev)
 static void sprd_dma_disable(struct sprd_dma_dev *sdev)
 {
 	clk_disable_unprepare(sdev->clk);
-
-	/*
-	 * Need to check if we need disable the optional ashb_clk for AGCP DMA.
-	 */
-	if (!IS_ERR(sdev->ashb_clk))
-		clk_disable_unprepare(sdev->ashb_clk);
+	clk_disable_unprepare(sdev->ashb_clk);
 }
 
 static void sprd_dma_set_uid(struct sprd_dma_chn *schan)
-- 
2.36.1

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

[Wan Jiabing]

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@vivo.com>
---
 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;
 	}
 
 	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);
+	clk_disable_unprepare(clk);
+	clk_put(clk);
+
 	return NULL;
 }
 
-- 
2.36.1

[PATCH 4/4] dmaengine: xgene-dma: Remove unneeded ERROR check before clk_disable_unprepare

[Wan Jiabing]

clk_disable_unprepare() already checks ERROR by using IS_ERR_OR_NULL.
Remove unneeded ERROR check for pdma->clk.

Signed-off-by: Wan Jiabing <wanjiabing@vivo.com>
---
 drivers/dma/xgene-dma.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/drivers/dma/xgene-dma.c b/drivers/dma/xgene-dma.c
index 3589b4ef50b8..7f0088b09714 100644
--- a/drivers/dma/xgene-dma.c
+++ b/drivers/dma/xgene-dma.c
@@ -1769,8 +1769,7 @@ static int xgene_dma_probe(struct platform_device *pdev)
 
 err_dma_mask:
 err_clk_enable:
-	if (!IS_ERR(pdma->clk))
-		clk_disable_unprepare(pdma->clk);
+	clk_disable_unprepare(pdma->clk);
 
 	return ret;
 }
@@ -1794,8 +1793,7 @@ static int xgene_dma_remove(struct platform_device *pdev)
 		xgene_dma_delete_chan_rings(chan);
 	}
 
-	if (!IS_ERR(pdma->clk))
-		clk_disable_unprepare(pdma->clk);
+	clk_disable_unprepare(pdma->clk);
 
 	return 0;
 }
-- 
2.36.1

Re: [PATCH 2/4] dmaengine: sprd-dma: Remove unneeded ERROR check before clk_disable_unprepare

[Krzysztof Kozlowski]

On 16/05/2022 10:41, Wan Jiabing wrote:
> clk_disable_unprepare() already checks ERROR by using IS_ERR_OR_NULL.

Hmm, maybe I am looking at different sources, but which commit
introduced IS_ERR_OR_NULL() check? Where is it in the sources?



Best regards,
Krzysztof

Re: [PATCH 2/4] dmaengine: sprd-dma: Remove unneeded ERROR check before clk_disable_unprepare

[Jiabing Wan]

Hi,

On 2022/5/17 23:13, Krzysztof Kozlowski wrote:
> On 16/05/2022 10:41, Wan Jiabing wrote:
>> clk_disable_unprepare() already checks ERROR by using IS_ERR_OR_NULL.
> Hmm, maybe I am looking at different sources, but which commit
> introduced IS_ERR_OR_NULL() check? Where is it in the sources?
>
In commit 4dff95dc9477a, IS_ERR_OR_NULL check is added in clk_disable() 
and clk_unprepare().
And clk_disable_unprepare() just calls clk_disable() and clk_unprepare():

static inline void clk_disable_unprepare(struct clk *clk)
{
      clk_disable(clk);
      clk_unprepare(clk);
}
>
> Best regards,
> Krzysztof

Thanks,
Wan Jiabing

Re: [PATCH 2/4] dmaengine: sprd-dma: Remove unneeded ERROR check before clk_disable_unprepare

[Krzysztof Kozlowski]

On 18/05/2022 04:44, Jiabing Wan wrote:
> Hi,
> 
> On 2022/5/17 23:13, Krzysztof Kozlowski wrote:
>> On 16/05/2022 10:41, Wan Jiabing wrote:
>>> clk_disable_unprepare() already checks ERROR by using IS_ERR_OR_NULL.
>> Hmm, maybe I am looking at different sources, but which commit
>> introduced IS_ERR_OR_NULL() check? Where is it in the sources?
>>
> In commit 4dff95dc9477a, IS_ERR_OR_NULL check is added in clk_disable() 
> and clk_unprepare().
> And clk_disable_unprepare() just calls clk_disable() and clk_unprepare():

Thank you, indeed, I was mislead a bit by clk_prepare() which is not
symmetric.



Best regards,
Krzysztof

Re: [PATCH 1/4] dmaengine: ep93xx_dma: Remove unneeded ERROR check before clk_put

[Krzysztof Kozlowski]

On 16/05/2022 10:41, Wan Jiabing wrote:
> clk_put() already uses !clk and IS_ERR(clk) to check ERROR or NULL.
> Remove unneeded ERROR or NULL check for edmac->clk.
> 
> Signed-off-by: Wan Jiabing <wanjiabing@vivo.com>
> ---
>  drivers/dma/ep93xx_dma.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/drivers/dma/ep93xx_dma.c b/drivers/dma/ep93xx_dma.c
> index 971ff5f9ae84..60dc7b3f3d0d 100644
> --- a/drivers/dma/ep93xx_dma.c
> +++ b/drivers/dma/ep93xx_dma.c
> @@ -1398,8 +1398,7 @@ static int __init ep93xx_dma_probe(struct platform_device *pdev)
>  	if (unlikely(ret)) {
>  		for (i = 0; i < edma->num_channels; i++) {
>  			struct ep93xx_dma_chan *edmac = &edma->channels[i];
> -			if (!IS_ERR_OR_NULL(edmac->clk))
> -				clk_put(edmac->clk);
> +			clk_put(edmac->clk);

clk_put() which calls __clk_put() seems to print warning on IS_ERR, so
this does not look equivalent code.


Best regards,
Krzysztof

Re: [PATCH 2/4] dmaengine: sprd-dma: Remove unneeded ERROR check before clk_disable_unprepare

[Krzysztof Kozlowski]

On 16/05/2022 10:41, Wan Jiabing wrote:
> clk_disable_unprepare() already checks ERROR by using IS_ERR_OR_NULL.
> Remove unneeded ERROR check for sdev->ashb_clk.
> 
> Signed-off-by: Wan Jiabing <wanjiabing@vivo.com>


Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>


Best regards,
Krzysztof

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

[Krzysztof Kozlowski]

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@vivo.com>
> ---
>  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.

>  	}
>  
>  	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);
> +	clk_disable_unprepare(clk);
> +	clk_put(clk);
> +
>  	return NULL;
>  }
>  


Best regards,
Krzysztof

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@vivo.com>
>> ---
>>   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