iommu: Fix error handling in probe_acpi_namespace_devices()

hulk inclusion
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I65QZY

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

Fix smatch error in probe_acpi_namespace_devices().

In probe_acpi_namespace_devices(), if device_to_iommu() returns NULL,
unlock operation is needed before return.

Fixes: d6602228 ("iommu/vt-d:Add support for detecting ACPI device, in RMRR")
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>
Reviewed-by: NXiongfeng Wang <wangxiongfeng2@huawei.com>
Reviewed-by: NHanjun Guo <guohanjun@huawei.com>

drivers/iommu/intel/iommu.c

@@ -4995,8 +4995,10 @@ static int __init probe_acpi_namespace_devices(void)
 				}
 
 				iommu = device_to_iommu(dev, &bus, &devfn);
-				if (!iommu)
-					return -ENODEV;
+				if (!iommu) {
+					ret = -ENODEV;
+					goto unlock;
+				}
 				info = dmar_search_domain_by_dev_info(iommu->segment, bus, devfn);
 				if (!info) {
 					pn->dev->bus->iommu_ops = &intel_iommu_ops;
@@ -5011,8 +5013,10 @@ static int __init probe_acpi_namespace_devices(void)
 			}
 			if (!pn_dev) {
 				iommu = device_to_iommu(dev, &bus, &devfn);
-				if (!iommu)
-					return -ENODEV;
+				if (!iommu) {
+					ret = -ENODEV;
+					goto unlock;
+				}
 				info = dmar_search_domain_by_dev_info(iommu->segment, bus, devfn);
 				if (!info) {
 					dev->bus->iommu_ops = &intel_iommu_ops;