iommu/vt-d: fix PCI device reference leakage on error recovery path

Function dmar_parse_dev_scope() should release the PCI device reference
count gained in function dmar_parse_one_dev_scope() on error recovery,
otherwise it will cause PCI device object leakage.

This patch also introduces dmar_free_dev_scope(), which will be used
to support DMAR device hotplug.

Reviewed-by: Yijing Wang <wangyijing@huawei.com>
Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
Signed-off-by: Joerg Roedel <joro@8bytes.org>

1 files changed, 12 insertions, 2 deletions

diff --git a/drivers/iommu/dmar.c b/drivers/iommu/dmar.c
index fb35d1bd19e1..28d93b68ff02 100644
--- a/drivers/iommu/dmar.c
+++ b/drivers/iommu/dmar.c
@@ -100,7 +100,6 @@ static int __init dmar_parse_one_dev_scope(struct acpi_dmar_device_scope *scope,
         if (!pdev) {
                 pr_warn("Device scope device [%04x:%02x:%02x.%02x] not found\n",
                         segment, scope->bus, path->device, path->function);
-                *dev = NULL;
                 return 0;
         }
         if ((scope->entry_type == ACPI_DMAR_SCOPE_TYPE_ENDPOINT && \
@@ -151,7 +150,7 @@ int __init dmar_parse_dev_scope(void *start, void *end, int *cnt,
                         ret = dmar_parse_one_dev_scope(scope,
                                 &(*devices)[index], segment);
                         if (ret) {
-                                kfree(*devices);
+                                dmar_free_dev_scope(devices, cnt);
                                 return ret;
                         }
                         index ++;
@@ -162,6 +161,17 @@ int __init dmar_parse_dev_scope(void *start, void *end, int *cnt,
         return 0;
 }
 
+void dmar_free_dev_scope(struct pci_dev ***devices, int *cnt)
+{
+        if (*devices && *cnt) {
+                while (--*cnt >= 0)
+                        pci_dev_put((*devices)[*cnt]);
+                kfree(*devices);
+                *devices = NULL;
+                *cnt = 0;
+        }
+}
+
 /**
  * dmar_parse_one_drhd - parses exactly one DMA remapping hardware definition
  * structure which uniquely represent one DMA remapping hardware unit