Re: [PATCH] iommu/arm-smmu-v3: fix resource_size check

[Robin Murphy]

On 26/12/2019 9:50 am, Masahiro Yamada wrote:
> This is an off-by-one mistake.
>
> resource_size() returns res->end - res->start + 1.

Heh, despite the optimism of "Avoid one-off errors by introducing a 
resource_size() function", life finds a way...

Reviewed-by: Robin Murphy <robin.murphy@xxxxxxx>

> Signed-off-by: Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx>
> ---
>
>   drivers/iommu/arm-smmu-v3.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c
> index d9e0d9c19b4f..b463599559d2 100644
> --- a/drivers/iommu/arm-smmu-v3.c
> +++ b/drivers/iommu/arm-smmu-v3.c
> @@ -3599,7 +3599,7 @@ static int arm_smmu_device_probe(struct platform_device *pdev)
>   
>   	/* Base address */
>   	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> -	if (resource_size(res) + 1 < arm_smmu_resource_size(smmu)) {
> +	if (resource_size(res) < arm_smmu_resource_size(smmu)) {
>   		dev_err(dev, "MMIO region too small (%pr)\n", res);
>   		return -EINVAL;
>   	}