Re: [PATCH] dma-mapping: add unlikely hint to error path in dma_mapping_error

[Robin Murphy <robin.murphy@arm.com>]

On 2021-03-26 21:03, Heiner Kallweit wrote:
> Zillions of drivers use the unlikely() hint when checking the result of
> dma_mapping_error(). This is an inline function anyway, so we can move
> the hint into the function and remove it from drivers over time.

I'm pretty sure I reviewed this last time - please remember to pick up 
tags from previous versions when reposting.

Thanks,
Robin.

> Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
> ---
> This is a resend of a patch from Dec 2020 when I tried to do it
> tree-wide. Now start with the actual change, drivers can be changed
> afterwards, maybe per subsystem.
> ---
>   include/linux/dma-mapping.h | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
> index e9d19b974..183e7103a 100644
> --- a/include/linux/dma-mapping.h
> +++ b/include/linux/dma-mapping.h
> @@ -95,7 +95,7 @@ static inline int dma_mapping_error(struct device *dev, dma_addr_t dma_addr)
>   {
>   	debug_dma_mapping_error(dev, dma_addr);
>   
> -	if (dma_addr == DMA_MAPPING_ERROR)
> +	if (unlikely(dma_addr == DMA_MAPPING_ERROR))
>   		return -ENOMEM;
>   	return 0;
>   }
> 
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