Subject: Re: [PATCH v2 7/8] iommu/arm-smmu-v3: Improve add_device() error handling

From: Jonathan Cameron <[email-masked]>
Date: Mon, 11 Nov 2019 15:58:30 +0000

On Fri, 8 Nov 2019 16:25:07 +0100
Jean-Philippe Brucker <[email-masked]> wrote:

> Let add_device() clean up after itself. The iommu_bus_init() function
> does call remove_device() on error, but other sites (e.g. of_iommu) do
> not.
> 
> Don't free level-2 stream tables because we'd have to track if we
> allocated each of them or if they are used by other endpoints. It's not
> worth the hassle since they are managed resources.
> 
> Reviewed-by: Eric Auger <[email-masked]>
> Signed-off-by: Jean-Philippe Brucker <[email-masked]>

Potentially some fun around reordering of last few actions, but
doesn't seem there is any real connection between them so should be
fine.

Reviewed-by: Jonathan Cameron <[email-masked]>

> ---
>  drivers/iommu/arm-smmu-v3.c | 28 +++++++++++++++++++++-------
>  1 file changed, 21 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c
> index 82eac89ee187..88ec0bf33492 100644
> --- a/drivers/iommu/arm-smmu-v3.c
> +++ b/drivers/iommu/arm-smmu-v3.c
> @@ -2826,14 +2826,16 @@ static int arm_smmu_add_device(struct device *dev)
>  	for (i = 0; i < master->num_sids; i++) {
>  		u32 sid = master->sids[i];
>  
> -		if (!arm_smmu_sid_in_range(smmu, sid))
> -			return -ERANGE;
> +		if (!arm_smmu_sid_in_range(smmu, sid)) {
> +			ret = -ERANGE;
> +			goto err_free_master;
> +		}
>  
>  		/* Ensure l2 strtab is initialised */
>  		if (smmu->features & ARM_SMMU_FEAT_2_LVL_STRTAB) {
>  			ret = arm_smmu_init_l2_strtab(smmu, sid);
>  			if (ret)
> -				return ret;
> +				goto err_free_master;
>  		}
>  	}
>  
> @@ -2843,13 +2845,25 @@ static int arm_smmu_add_device(struct device *dev)
>  		master->ssid_bits = min_t(u8, master->ssid_bits,
>  					  CTXDESC_LINEAR_CDMAX);
>  
> +	ret = iommu_device_link(&smmu->iommu, dev);
> +	if (ret)
> +		goto err_free_master;
> +
>  	group = iommu_group_get_for_dev(dev);
> -	if (!IS_ERR(group)) {
> -		iommu_group_put(group);
> -		iommu_device_link(&smmu->iommu, dev);
> +	if (IS_ERR(group)) {
> +		ret = PTR_ERR(group);
> +		goto err_unlink;
>  	}
>  
> -	return PTR_ERR_OR_ZERO(group);
> +	iommu_group_put(group);
> +	return 0;
> +
> +err_unlink:
> +	iommu_device_unlink(&smmu->iommu, dev);
> +err_free_master:
> +	kfree(master);
> +	fwspec->iommu_priv = NULL;
> +	return ret;
>  }
>  
>  static void arm_smmu_remove_device(struct device *dev)

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