iommu/vt-d: Unlink device if failed to add to group

mainline inclusion
from mainline-v5.5-rc6
commit f78947c4
category: bugfix
bugzilla: 96934
CVE: NA

-------------------------------------------------

If the device fails to be added to the group, make sure to unlink the
reference before returning.
Signed-off-by: NJon Derrick <jonathan.derrick@intel.com>
Fixes: 39ab9555 ("iommu: Add sysfs bindings for struct iommu_device")
Acked-by: NLu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: NJoerg Roedel <jroedel@suse.de>

Conflict:
	drivers/iommu/intel-iommu.c
Signed-off-by: NNanyong Sun <sunnanyong@huawei.com>
Reviewed-by: NKefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>

drivers/iommu/intel-iommu.c

@@ -5239,6 +5239,7 @@ static int intel_iommu_add_device(struct device *dev)
 	struct intel_iommu *iommu;
 	struct iommu_group *group;
 	u8 bus, devfn;
+	int ret;
 
 	iommu = device_to_iommu(dev, &bus, &devfn);
 	if (!iommu)
@@ -5248,11 +5249,17 @@ static int intel_iommu_add_device(struct device *dev)
 
 	group = iommu_group_get_for_dev(dev);
 
-	if (IS_ERR(group))
-		return PTR_ERR(group);
+	if (IS_ERR(group)) {
+		ret = PTR_ERR(group);
+		goto unlink;
+	}
 
 	iommu_group_put(group);
 	return 0;
+
+unlink:
+	iommu_device_unlink(&iommu->iommu, dev);
+	return ret;
 }
 
 static void intel_iommu_remove_device(struct device *dev)