linux-kernel - RE: [PATCH 1/2] dmaengine: fsl-edma: cleanup chan after dma_async_device

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Message-ID:
 <PAXPR04MB845988B45C8408112563764E88512@PAXPR04MB8459.eurprd04.prod.outlook.com>
Date: Mon, 4 Nov 2024 05:35:02 +0000
From: Peng Fan <peng.fan@....com>
To: Frank Li <frank.li@....com>, "Peng Fan (OSS)" <peng.fan@....nxp.com>
CC: Vinod Koul <vkoul@...nel.org>, "open list:FREESCALE eDMA DRIVER"
	<imx@...ts.linux.dev>, "open list:FREESCALE eDMA DRIVER"
	<dmaengine@...r.kernel.org>, open list <linux-kernel@...r.kernel.org>
Subject: RE: [PATCH 1/2] dmaengine: fsl-edma: cleanup chan after
 dma_async_device_unregister

> Subject: Re: [PATCH 1/2] dmaengine: fsl-edma: cleanup chan after
> dma_async_device_unregister
> 
> On Fri, Nov 01, 2024 at 06:14:09PM +0800, Peng Fan (OSS) wrote:
> > From: Peng Fan <peng.fan@....com>
> >
> > There is kernel dump when do module test:
> > sysfs: cannot create duplicate filename
> '/devices/platform/soc@...4000000.bus/44000000.dma-
> controller/dma/dma0chan0'
> >  __dma_async_device_channel_register+0x128/0x19c
> >  dma_async_device_register+0x150/0x454
> >  fsl_edma_probe+0x6cc/0x8a0
> >  platform_probe+0x68/0xc8
> >
> > Clean up chan after dma_async_device_unregister to address this.
> 
> Can you explan why move it after dma_async_device_unregiste() can
> fix this problem?

fsl_edma_cleanup_vchan will unlink vchan.chan.device_node,
while dma_async_device_unregister  needs the link to do
__dma_async_device_channel_unregister. So need move
fsl_edma_cleanup_vchan after dma_async_device_unregister
to make sure channel could be freed.

I will include this in V2 commit log.

Thanks,
Peng.

> 
> Frank
> >
> > Fixes: 6f93b93b2a1b ("dmaengine: fsl-edma: kill the tasklets upon
> > exit")
> > Signed-off-by: Peng Fan <peng.fan@....com>
> > ---
> >  drivers/dma/fsl-edma-main.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/dma/fsl-edma-main.c b/drivers/dma/fsl-edma-
> main.c
> > index f9f1eda79254..01bd5cb24a49 100644
> > --- a/drivers/dma/fsl-edma-main.c
> > +++ b/drivers/dma/fsl-edma-main.c
> > @@ -668,9 +668,9 @@ static void fsl_edma_remove(struct
> platform_device *pdev)
> >  	struct fsl_edma_engine *fsl_edma =
> platform_get_drvdata(pdev);
> >
> >  	fsl_edma_irq_exit(pdev, fsl_edma);
> > -	fsl_edma_cleanup_vchan(&fsl_edma->dma_dev);
> >  	of_dma_controller_free(np);
> >  	dma_async_device_unregister(&fsl_edma->dma_dev);
> > +	fsl_edma_cleanup_vchan(&fsl_edma->dma_dev);
> >  	fsl_disable_clocks(fsl_edma, fsl_edma->drvdata->dmamuxs);  }
> >
> > --
> > 2.37.1
> >