Re: [PATCH v7 12/14] iommu/arm-smmu-v3: Introduce struct arm_smmu_vmaster

[Jason Gunthorpe]

On Mon, Feb 24, 2025 at 03:45:33PM -0800, Nicolin Chen wrote:

> --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-iommufd.c
> +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-iommufd.c
> @@ -95,8 +95,6 @@ int arm_smmu_attach_prepare_vmaster(struct arm_smmu_attach_state *state,
>  
>  	iommu_group_mutex_assert(state->master->dev);
>  
> -	if (domain->type != IOMMU_DOMAIN_NESTED)
> -		return 0;
>  	nested_domain = to_smmu_nested_domain(domain);
>  
>  	/* Skip invalid vSTE */
> @@ -122,19 +120,9 @@ void arm_smmu_attach_commit_vmaster(struct arm_smmu_attach_state *state)
>  {
>  	struct arm_smmu_master *master = state->master;
>  
> -	mutex_lock(&master->smmu->streams_mutex);
> -	if (state->vmaster != master->vmaster) {
> -		kfree(master->vmaster);
> -		master->vmaster = state->vmaster;
> -	}
> -	mutex_unlock(&master->smmu->streams_mutex);
> -}
> -
> -void arm_smmu_master_clear_vmaster(struct arm_smmu_master *master)
> -{
>  	mutex_lock(&master->smmu->streams_mutex);
>  	kfree(master->vmaster);
> -	master->vmaster = NULL;
> +	master->vmaster = state->vmaster;
>  	mutex_unlock(&master->smmu->streams_mutex);
>  }

I'd leave the clear_vmaster just for clarity. Commit should not be
unpaired with prepare in the other functions.

It looks fine with this on top too

Reviewed-by: Jason Gunthorpe <jgg@xxxxxxxxxx>

Jason