linux-kernel - Re: [PATCH] [v5] dmaengine: tegra210-adma: Fix runtime PM imbalance on error

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Date:   Wed, 24 Jun 2020 09:58:58 +0100
From:   Jon Hunter <jonathanh@...dia.com>
To:     Dinghao Liu <dinghao.liu@....edu.cn>, <kjlu@....edu>
CC:     Laxman Dewangan <ldewangan@...dia.com>,
        Dan Williams <dan.j.williams@...el.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] [v5] dmaengine: tegra210-adma: Fix runtime PM imbalance
 on error


On 24/06/2020 07:46, Dinghao Liu wrote:
> pm_runtime_get_sync() increments the runtime PM usage counter even
> when it returns an error code. Thus a pairing decrement is needed on
> the error handling path to keep the counter balanced.

I was hoping you would mention explicitly why we are using _noidle in
the changelog. However, let's not beat the dead horse any more and just
merge this. So ...

Reviewed-by: Jon Hunter <jonathanh@...dia.com>

Thanks
Jon

> Signed-off-by: Dinghao Liu <dinghao.liu@....edu.cn>
> ---
> 
> Changelog:
> 
> v2: - Merge two patches that fix runtime PM imbalance in
>       tegra_adma_probe() and tegra_adma_alloc_chan_resources()
>       respectively.
> 
> v3: - Use pm_runtime_put_noidle() instead of pm_runtime_put_sync()
>       in tegra_adma_alloc_chan_resources(). _noidle() is the simplest
>       one and it is sufficient for fixing this bug.
> 
> v4: - Use pm_runtime_put_noidle() instead of pm_runtime_put_sync()
>       in tegra_adma_probe(). _noidle() is the simplest one and it is
>       sufficient for fixing this bug.
> 
> v5: - Refine commit message.
> ---
>  drivers/dma/tegra210-adma.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/dma/tegra210-adma.c b/drivers/dma/tegra210-adma.c
> index db58d7e4f9fe..c5fa2ef74abc 100644
> --- a/drivers/dma/tegra210-adma.c
> +++ b/drivers/dma/tegra210-adma.c
> @@ -658,6 +658,7 @@ static int tegra_adma_alloc_chan_resources(struct dma_chan *dc)
>  
>  	ret = pm_runtime_get_sync(tdc2dev(tdc));
>  	if (ret < 0) {
> +		pm_runtime_put_noidle(tdc2dev(tdc));
>  		free_irq(tdc->irq, tdc);
>  		return ret;
>  	}
> @@ -869,8 +870,10 @@ static int tegra_adma_probe(struct platform_device *pdev)
>  	pm_runtime_enable(&pdev->dev);
>  
>  	ret = pm_runtime_get_sync(&pdev->dev);
> -	if (ret < 0)
> +	if (ret < 0) {
> +		pm_runtime_put_noidle(&pdev->dev);
>  		goto rpm_disable;
> +	}
>  
>  	ret = tegra_adma_init(tdma);
>  	if (ret)
> 

-- 
nvpublic