[PATCH v2 02/13] iommu/amd: Drop unnecessary checks in amd_iommu_attach_device()

[PATCH v2 02/13] iommu/amd: Drop unnecessary checks in amd_iommu_attach_device()

[Nicolin Chen]

The same checks are done in amd_iommu_probe_device(). If any of them fails
there, then the device won't get a group, so there's no way for it to even
reach amd_iommu_attach_device any more.

Suggested-by: Robin Murphy <robin.murphy@arm.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
---
 drivers/iommu/amd/iommu.c | 12 ++----------
 1 file changed, 2 insertions(+), 10 deletions(-)

diff --git a/drivers/iommu/amd/iommu.c b/drivers/iommu/amd/iommu.c
index 828672a46a3d..930d9946b9f7 100644
--- a/drivers/iommu/amd/iommu.c
+++ b/drivers/iommu/amd/iommu.c
@@ -2135,21 +2135,13 @@ static void amd_iommu_detach_device(struct iommu_domain *dom,
 static int amd_iommu_attach_device(struct iommu_domain *dom,
 				   struct device *dev)
 {
+	struct iommu_dev_data *dev_data = dev_iommu_priv_get(dev);
 	struct protection_domain *domain = to_pdomain(dom);
-	struct iommu_dev_data *dev_data;
-	struct amd_iommu *iommu;
+	struct amd_iommu *iommu = rlookup_amd_iommu(dev);
 	int ret;
 
-	if (!check_device(dev))
-		return -EINVAL;
-
-	dev_data = dev_iommu_priv_get(dev);
 	dev_data->defer_attach = false;
 
-	iommu = rlookup_amd_iommu(dev);
-	if (!iommu)
-		return -EINVAL;
-
 	if (dev_data->domain)
 		detach_device(dev);
 
-- 
2.17.1

Re: [PATCH v2 02/13] iommu/amd: Drop unnecessary checks in amd_iommu_attach_device()

[Vasant Hegde]

On 9/14/2022 10:44 AM, Nicolin Chen wrote:
> The same checks are done in amd_iommu_probe_device(). If any of them fails
> there, then the device won't get a group, so there's no way for it to even
> reach amd_iommu_attach_device any more.
> 
> Suggested-by: Robin Murphy <robin.murphy@arm.com>
> Cc: Joerg Roedel <joro@8bytes.org>
> Cc: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
> Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>

Looks good to me.

Reviewed-by: Vasant Hegde <vasant.hegde@amd.com>

-Vasant

> ---
>  drivers/iommu/amd/iommu.c | 12 ++----------
>  1 file changed, 2 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/iommu/amd/iommu.c b/drivers/iommu/amd/iommu.c
> index 828672a46a3d..930d9946b9f7 100644
> --- a/drivers/iommu/amd/iommu.c
> +++ b/drivers/iommu/amd/iommu.c
> @@ -2135,21 +2135,13 @@ static void amd_iommu_detach_device(struct iommu_domain *dom,
>  static int amd_iommu_attach_device(struct iommu_domain *dom,
>  				   struct device *dev)
>  {
> +	struct iommu_dev_data *dev_data = dev_iommu_priv_get(dev);
>  	struct protection_domain *domain = to_pdomain(dom);
> -	struct iommu_dev_data *dev_data;
> -	struct amd_iommu *iommu;
> +	struct amd_iommu *iommu = rlookup_amd_iommu(dev);
>  	int ret;
>  
> -	if (!check_device(dev))
> -		return -EINVAL;
> -
> -	dev_data = dev_iommu_priv_get(dev);
>  	dev_data->defer_attach = false;
>  
> -	iommu = rlookup_amd_iommu(dev);
> -	if (!iommu)
> -		return -EINVAL;
> -
>  	if (dev_data->domain)
>  		detach_device(dev);
>