On 29/01/2020 18.35, 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.
>
> Fixes: 71723a96b8b1 ("dmaengine: Create symlinks between DMA channels and slaves")
> Signed-off-by: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>
> ---
> 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..27b64a665347 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;
It should be:
return chan ? chan : ERR_PTR(-EPROBE_DEFER);
dma_request_chan() should never return NULL, it either returns the
dma_chan, or ERR_PTR().
>
> found:
> chan->slave = dev;
>
- Péter
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