[PATCH -next] iommu/arm-smmu: Fix missing unlock on error in arm_smmu_device_group()

[Will Deacon]

On Fri, Aug 20, 2021 at 03:49:49PM +0800, Yang Yingliang wrote:
> Add the missing unlock before return from function arm_smmu_device_group()
> in the error handling case.
> 
> Fixes: b1a1347912a7 ("iommu/arm-smmu: Fix race condition during iommu_group creation")
> Reported-by: Hulk Robot <hulkci at huawei.com>
> Signed-off-by: Yang Yingliang <yangyingliang at huawei.com>
> ---
>  drivers/iommu/arm/arm-smmu/arm-smmu.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu.c b/drivers/iommu/arm/arm-smmu/arm-smmu.c
> index 73893180ec7e..4bc75c4ce402 100644
> --- a/drivers/iommu/arm/arm-smmu/arm-smmu.c
> +++ b/drivers/iommu/arm/arm-smmu/arm-smmu.c
> @@ -1478,8 +1478,10 @@ static struct iommu_group *arm_smmu_device_group(struct device *dev)
>  	mutex_lock(&smmu->stream_map_mutex);
>  	for_each_cfg_sme(cfg, fwspec, i, idx) {
>  		if (group && smmu->s2crs[idx].group &&
> -		    group != smmu->s2crs[idx].group)
> +		    group != smmu->s2crs[idx].group) {
> +			mutex_unlock(&smmu->stream_map_mutex);
>  			return ERR_PTR(-EINVAL);
> +		}

Urgh, I should really have spotted that in review. Thanks:

Acked-by: Will Deacon <will at kernel.org>

Joerg -- please can you throw this on top?

Will