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

Auger Eric
2019-07-08T07:58:34Z

Hi Jean,

On 6/10/19 8:47 PM, Jean-Philippe Brucker wrote:
> Let add_device() clean up behind 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.
>
> Signed-off-by: Jean-Philippe Brucker <jean-philippe.brucker@arm.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>

Thanks

Eric
> ---
> 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 633d829f246f..972bfb80f964 100644
> --- a/drivers/iommu/arm-smmu-v3.c
> +++ b/drivers/iommu/arm-smmu-v3.c
> @@ -2398,14 +2398,16 @@ 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;
> }
> }
>
> @@ -2419,13 +2421,25 @@ static int arm_smmu_add_device(struct device *dev)
> if (!(smmu->features & ARM_SMMU_FEAT_2_LVL_CDTAB))
> master->ssid_bits = min(master->ssid_bits, 10U);
>
> + 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)
>