[PATCH v2] dmaengine: Fix return value for dma_requrest_chan() in case of failure

[PATCH v2] dmaengine: Fix return value for dma_requrest_chan() in case of failure

[Marek Szyprowski]

Commit 71723a96b8b1 ("dmaengine: Create symlinks between DMA channels and
slaves") changed the dma_request_chan() function flow in such a way that
it always returns EPROBE_DEFER in case of channels that cannot be found.
This break the operation of the devices which have optional DMA channels
as it puts their drivers in endless deferred probe loop. Fix this by
propagating the proper error value.

Fixes: 71723a96b8b1 ("dmaengine: Create symlinks between DMA channels and slaves")
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
---
 drivers/dma/dmaengine.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c
index f3ef4edd4de1..7b1cefc3213a 100644
--- a/drivers/dma/dmaengine.c
+++ b/drivers/dma/dmaengine.c
@@ -759,7 +759,7 @@ struct dma_chan *dma_request_chan(struct device *dev, const char *name)
 	if (!IS_ERR_OR_NULL(chan))
 		goto found;
 
-	return ERR_PTR(-EPROBE_DEFER);
+	return chan ? chan : ERR_PTR(-EPROBE_DEFER);
 
 found:
 	chan->slave = dev;
-- 
2.17.1

Re: [PATCH v2] dmaengine: Fix return value for dma_requrest_chan() in case of failure

[Geert Uytterhoeven]

Hi Marek,

s/dma_requrest_chan/dma_request_chan/ in one-line summary.

On Thu, Jan 30, 2020 at 8:08 AM Marek Szyprowski
<m.szyprowski@samsung.com> wrote:
> Commit 71723a96b8b1 ("dmaengine: Create symlinks between DMA channels and
> slaves") changed the dma_request_chan() function flow in such a way that
> it always returns EPROBE_DEFER in case of channels that cannot be found.
> This break the operation of the devices which have optional DMA channels
> as it puts their drivers in endless deferred probe loop. Fix this by
> propagating the proper error value.
>
> Fixes: 71723a96b8b1 ("dmaengine: Create symlinks between DMA channels and slaves")
> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>

Sorry for breaking this, and thanks a lot for your fix!

Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

Re: [PATCH v2] dmaengine: Fix return value for dma_requrest_chan() in case of failure

[Vinod Koul]

On 30-01-20, 08:08, Marek Szyprowski wrote:
> Commit 71723a96b8b1 ("dmaengine: Create symlinks between DMA channels and
> slaves") changed the dma_request_chan() function flow in such a way that
> it always returns EPROBE_DEFER in case of channels that cannot be found.
> This break the operation of the devices which have optional DMA channels
> as it puts their drivers in endless deferred probe loop. Fix this by
> propagating the proper error value.

Fixed the title and Applied, thanks

-- 
~Vinod