[PATCH 01/10] iommu/arm-smmu: Drop if with an always false condition

[Robin Murphy]

On 21/03/2023 8:41 am, Uwe Kleine-König wrote:
> The remove and shutdown callback are only called after probe completed
> successfully. In this case platform_set_drvdata() was called with a
> non-NULL argument and so smmu is never NULL. Other functions in this
> driver also don't check for smmu being non-NULL before using it.

Indeed, it seems this impossible condition has been here since day 1; 
shame on me for not paying more attention when Vladimir dutifully 
refactored it :)

Reviewed-by: Robin Murphy <robin.murphy at arm.com>

> Also note that returning an error code from a remove callback doesn't
> result in the device staying bound. It's still removed and devm allocated
> resources are freed (among others *smmu and the register mapping). So
> after an early exit to iommu device stayed around and using it probably
> oopses.
> 
> Signed-off-by: Uwe Kleine-König <u.kleine-koenig at pengutronix.de>
> ---
>   drivers/iommu/arm/arm-smmu/arm-smmu.c | 6 ------
>   1 file changed, 6 deletions(-)
> 
> diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu.c b/drivers/iommu/arm/arm-smmu/arm-smmu.c
> index 2ff7a72cf377..f4a36533ae47 100644
> --- a/drivers/iommu/arm/arm-smmu/arm-smmu.c
> +++ b/drivers/iommu/arm/arm-smmu/arm-smmu.c
> @@ -2195,9 +2195,6 @@ static void arm_smmu_device_shutdown(struct platform_device *pdev)
>   {
>   	struct arm_smmu_device *smmu = platform_get_drvdata(pdev);
>   
> -	if (!smmu)
> -		return;
> -
>   	if (!bitmap_empty(smmu->context_map, ARM_SMMU_MAX_CBS))
>   		dev_notice(&pdev->dev, "disabling translation\n");
>   
> @@ -2218,9 +2215,6 @@ static int arm_smmu_device_remove(struct platform_device *pdev)
>   {
>   	struct arm_smmu_device *smmu = platform_get_drvdata(pdev);
>   
> -	if (!smmu)
> -		return -ENODEV;
> -
>   	iommu_device_unregister(&smmu->iommu);
>   	iommu_device_sysfs_remove(&smmu->iommu);
>