Re: [PATCH] media: xilinx: Use dma_request_chan() instead dma_request_slave_channel()

From: Laurent Pinchart
Date: Thu Jan 09 2020 - 11:54:02 EST


Hello again,

On Thu, Jan 09, 2020 at 06:48:47PM +0200, Laurent Pinchart wrote:
> On Tue, Dec 17, 2019 at 12:42:35PM +0200, Peter Ujfalusi wrote:
> > dma_request_slave_channel() is a wrapper on top of dma_request_chan()
> > eating up the error code.
> >
> > By using dma_request_chan() directly the driver can support deferred
> > probing against DMA.
> >
> > Signed-off-by: Peter Ujfalusi <peter.ujfalusi@xxxxxx>
>
> Reviewed-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
>
> Vinod, could you please pick this up ?

I spoke too fast.

> > ---
> > drivers/media/platform/xilinx/xilinx-dma.c | 6 +++---
> > 1 file changed, 3 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/media/platform/xilinx/xilinx-dma.c b/drivers/media/platform/xilinx/xilinx-dma.c
> > index b211380a11f2..9ce515ff9c0a 100644
> > --- a/drivers/media/platform/xilinx/xilinx-dma.c
> > +++ b/drivers/media/platform/xilinx/xilinx-dma.c
> > @@ -725,10 +725,10 @@ int xvip_dma_init(struct xvip_composite_device *xdev, struct xvip_dma *dma,
> >
> > /* ... and the DMA channel. */
> > snprintf(name, sizeof(name), "port%u", port);
> > - dma->dma = dma_request_slave_channel(dma->xdev->dev, name);
> > - if (dma->dma == NULL) {
> > + dma->dma = dma_request_chan(dma->xdev->dev, name);
> > + if (IS_ERR(dma->dma)) {
> > dev_err(dma->xdev->dev, "no VDMA channel found\n");
> > - ret = -ENODEV;
> > + ret = PTR_ERR(dma->dma);
> > goto error;

At the error label, we have

error:
xvip_dma_cleanup(dma);
return ret;

and xvip_dma_cleanup() contains

if (dma->dma)
dma_release_channel(dma->dma);

You need to turn this into

if (!IS_ERR_OR_NULL(dma->dma))

or add a

dma->dma = NULL;

in the error case in xvip_dma_init().

> > }
> >

--
Regards,

Laurent Pinchart