[PATCH v2 6/6] gqa-win: get_pci_info: Replace 'while' with 2 calls of the function

[Kostiantyn Kostiuk <konstantin@daynix.com>]

Microsoft suggests this solution in the documentation:
https://docs.microsoft.com/en-us/windows/win32/api/setupapi/nf-setupapi-setupdigetdeviceinterfacedetaila

Signed-off-by: Kostiantyn Kostiuk <kkostiuk@redhat.com>
Signed-off-by: Kostiantyn Kostiuk <konstantin@daynix.com>
---
 qga/commands-win32.c | 30 ++++++++++++++++++++++++------
 1 file changed, 24 insertions(+), 6 deletions(-)

diff --git a/qga/commands-win32.c b/qga/commands-win32.c
index 3092566313..892082504f 100644
--- a/qga/commands-win32.c
+++ b/qga/commands-win32.c
@@ -636,10 +636,10 @@ static GuestPCIAddress *get_pci_info(int number, Error **errp)
         if (SetupDiEnumDeviceInterfaces(dev_info, &dev_info_data,
                                         &GUID_DEVINTERFACE_DISK, 0,
                                         &dev_iface_data)) {
-            while (!SetupDiGetDeviceInterfaceDetail(dev_info, &dev_iface_data,
-                                                    pdev_iface_detail_data,
-                                                    size, &size,
-                                                    &dev_info_data)) {
+            if (!SetupDiGetDeviceInterfaceDetail(dev_info, &dev_iface_data,
+                                                 pdev_iface_detail_data,
+                                                 size, &size,
+                                                 &dev_info_data)) {
                 if (GetLastError() == ERROR_INSUFFICIENT_BUFFER) {
                     pdev_iface_detail_data = g_malloc(size);
                     pdev_iface_detail_data->cbSize =
@@ -651,6 +651,16 @@ static GuestPCIAddress *get_pci_info(int number, Error **errp)
                 }
             }
 
+            if (!SetupDiGetDeviceInterfaceDetail(dev_info, &dev_iface_data,
+                                                 pdev_iface_detail_data,
+                                                 size, &size,
+                                                 &dev_info_data)) {
+                // pdev_iface_detail_data already is allocated
+                error_setg_win32(errp, GetLastError(),
+                                    "failed to get device interfaces");
+                goto end;
+            }
+
             dev_file = CreateFile(pdev_iface_detail_data->DevicePath, 0,
                                   FILE_SHARE_READ, NULL, OPEN_EXISTING, 0,
                                   NULL);
@@ -680,8 +690,8 @@ static GuestPCIAddress *get_pci_info(int number, Error **errp)
             ULONG dev_id_size = 0;
 
             size = 0;
-            while (!SetupDiGetDeviceInstanceId(dev_info, &dev_info_data,
-                                               parent_dev_id, size, &size)) {
+            if (!SetupDiGetDeviceInstanceId(dev_info, &dev_info_data,
+                                            parent_dev_id, size, &size)) {
                 if (GetLastError() == ERROR_INSUFFICIENT_BUFFER) {
                     parent_dev_id = g_malloc(size);
                 } else {
@@ -691,6 +701,14 @@ static GuestPCIAddress *get_pci_info(int number, Error **errp)
                 }
             }
 
+            if (!SetupDiGetDeviceInstanceId(dev_info, &dev_info_data,
+                                            parent_dev_id, size, &size)) {
+                // parent_dev_id already is allocated
+                error_setg_win32(errp, GetLastError(),
+                                    "failed to get device instance ID");
+                goto end;
+            }
+
             /*
              * CM API used here as opposed to
              * SetupDiGetDeviceProperty(..., DEVPKEY_Device_Parent, ...)
-- 
2.25.1