[PATCH -next] dmaengine: mediatek:Fix PM usage reference leak of tegra

[AngeloGioacchino Del Regno]

Il 18/03/22 09:08, Zhang Qilong ha scritto:
> From: zhangqilong <zhangqilong3 at huawei.com>
> 
> pm_runtime_get_sync will increment pm usage counter even it failed.
> Forgetting to putting operation will result in reference leak here.
> We fix it:
> 1) Replacing it with pm_runtime_resume_and_get to keep usage counter
>     balanced.
> 2) Add putting operation before returning error.
> 
> Fixes:9135408c3ace4 ("dmaengine: mediatek: Add MediaTek UART APDMA support")
> Signed-off-by: Zhang Qilong <zhangqilong3 at huawei.com>

Hello Zhang,

I agree with this change, but the commit message is misleading, as this is not
Tegra.

Please fix it.

Regards,
Angelo

> ---
>   drivers/dma/mediatek/mtk-uart-apdma.c | 9 ++++++---
>   1 file changed, 6 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/dma/mediatek/mtk-uart-apdma.c b/drivers/dma/mediatek/mtk-uart-apdma.c
> index 375e7e647df6..a1517ef1f4a0 100644
> --- a/drivers/dma/mediatek/mtk-uart-apdma.c
> +++ b/drivers/dma/mediatek/mtk-uart-apdma.c
> @@ -274,7 +274,7 @@ static int mtk_uart_apdma_alloc_chan_resources(struct dma_chan *chan)
>   	unsigned int status;
>   	int ret;
>   
> -	ret = pm_runtime_get_sync(mtkd->ddev.dev);
> +	ret = pm_runtime_resume_and_get(mtkd->ddev.dev);
>   	if (ret < 0) {
>   		pm_runtime_put_noidle(chan->device->dev);
>   		return ret;
> @@ -288,18 +288,21 @@ static int mtk_uart_apdma_alloc_chan_resources(struct dma_chan *chan)
>   	ret = readx_poll_timeout(readl, c->base + VFF_EN,
>   			  status, !status, 10, 100);
>   	if (ret)
> -		return ret;
> +		goto err_pm;
>   
>   	ret = request_irq(c->irq, mtk_uart_apdma_irq_handler,
>   			  IRQF_TRIGGER_NONE, KBUILD_MODNAME, chan);
>   	if (ret < 0) {
>   		dev_err(chan->device->dev, "Can't request dma IRQ\n");
> -		return -EINVAL;
> +		ret = -EINVAL;
> +		goto err_pm;
>   	}
>   
>   	if (mtkd->support_33bits)
>   		mtk_uart_apdma_write(c, VFF_4G_SUPPORT, VFF_4G_SUPPORT_CLR_B);
>   
> +err_pm:
> +	pm_runtime_put_noidle(mtkd->ddev.dev);
>   	return ret;
>   }
>   
>