[PATCH] dmaengine: tegra20: Fix runtime PM imbalance in tegra_dma_issue_pending

[PATCH] dmaengine: tegra20: Fix runtime PM imbalance in tegra_dma_issue_pending

[Dinghao Liu]

pm_runtime_get_sync() will increase the rumtime PM counter
even it returns an error. Thus a pairing decrement is needed
to prevent refcount leak. Fix this by replacing this API with
pm_runtime_resume_and_get(), which will not change the runtime
PM counter on error.

Signed-off-by: Dinghao Liu <dinghao.liu@zju.edu.cn>
---
 drivers/dma/tegra20-apb-dma.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/dma/tegra20-apb-dma.c b/drivers/dma/tegra20-apb-dma.c
index 71827d9b0aa1..73178afaf4c2 100644
--- a/drivers/dma/tegra20-apb-dma.c
+++ b/drivers/dma/tegra20-apb-dma.c
@@ -723,7 +723,7 @@ static void tegra_dma_issue_pending(struct dma_chan *dc)
 		goto end;
 	}
 	if (!tdc->busy) {
-		err = pm_runtime_get_sync(tdc->tdma->dev);
+		err = pm_runtime_resume_and_get(tdc->tdma->dev);
 		if (err < 0) {
 			dev_err(tdc2dev(tdc), "Failed to enable DMA\n");
 			goto end;
-- 
2.17.1

Re: [PATCH] dmaengine: tegra20: Fix runtime PM imbalance in tegra_dma_issue_pending

[Jon Hunter]

On 08/04/2021 08:11, Dinghao Liu wrote:
> pm_runtime_get_sync() will increase the rumtime PM counter
> even it returns an error. Thus a pairing decrement is needed
> to prevent refcount leak. Fix this by replacing this API with
> pm_runtime_resume_and_get(), which will not change the runtime
> PM counter on error.
> 
> Signed-off-by: Dinghao Liu <dinghao.liu@zju.edu.cn>
> ---
>  drivers/dma/tegra20-apb-dma.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/dma/tegra20-apb-dma.c b/drivers/dma/tegra20-apb-dma.c
> index 71827d9b0aa1..73178afaf4c2 100644
> --- a/drivers/dma/tegra20-apb-dma.c
> +++ b/drivers/dma/tegra20-apb-dma.c
> @@ -723,7 +723,7 @@ static void tegra_dma_issue_pending(struct dma_chan *dc)
>  		goto end;
>  	}
>  	if (!tdc->busy) {
> -		err = pm_runtime_get_sync(tdc->tdma->dev);
> +		err = pm_runtime_resume_and_get(tdc->tdma->dev);
>  		if (err < 0) {
>  			dev_err(tdc2dev(tdc), "Failed to enable DMA\n");
>  			goto end;
> 


Thanks! Looks like there are two instances of this that need fixing.

Cheers
Jon

-- 
nvpublic

Re: Re: [PATCH] dmaengine: tegra20: Fix runtime PM imbalance in tegra_dma_issue_pending

[dinghao.liu]

> On 08/04/2021 08:11, Dinghao Liu wrote:
> > pm_runtime_get_sync() will increase the rumtime PM counter
> > even it returns an error. Thus a pairing decrement is needed
> > to prevent refcount leak. Fix this by replacing this API with
> > pm_runtime_resume_and_get(), which will not change the runtime
> > PM counter on error.
> > 
> > Signed-off-by: Dinghao Liu <dinghao.liu@zju.edu.cn>
> > ---
> >  drivers/dma/tegra20-apb-dma.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/drivers/dma/tegra20-apb-dma.c b/drivers/dma/tegra20-apb-dma.c
> > index 71827d9b0aa1..73178afaf4c2 100644
> > --- a/drivers/dma/tegra20-apb-dma.c
> > +++ b/drivers/dma/tegra20-apb-dma.c
> > @@ -723,7 +723,7 @@ static void tegra_dma_issue_pending(struct dma_chan *dc)
> >  		goto end;
> >  	}
> >  	if (!tdc->busy) {
> > -		err = pm_runtime_get_sync(tdc->tdma->dev);
> > +		err = pm_runtime_resume_and_get(tdc->tdma->dev);
> >  		if (err < 0) {
> >  			dev_err(tdc2dev(tdc), "Failed to enable DMA\n");
> >  			goto end;
> > 
> 
> 
> Thanks! Looks like there are two instances of this that need fixing.
> 

Thanks for pointing out this! I will fix this and send a new patch soon.

Regards,
Dinghao