linux-kernel - Re: [PATCH] dmaengine: tegra20: Fix runtime PM imbalance in tegra_dma_issue

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Date:   Thu, 8 Apr 2021 13:33:00 +0100
From:   Jon Hunter <jonathanh@...dia.com>
To:     Dinghao Liu <dinghao.liu@....edu.cn>, <kjlu@....edu>
CC:     Laxman Dewangan <ldewangan@...dia.com>,
        Vinod Koul <vkoul@...nel.org>,
        Thierry Reding <thierry.reding@...il.com>,
        <dmaengine@...r.kernel.org>, <linux-tegra@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] dmaengine: tegra20: Fix runtime PM imbalance in
 tegra_dma_issue_pending


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@....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

-- 
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