qga/commands-posix: Rework build_guest_fsinfo_for_real_device() function

We are going to support non-PCI devices soon. For this we need to split
the generic GuestDiskAddress and GuestDiskAddressList memory allocation
and list chaining into a separate function first.

Signed-off-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>

qga/commands-posix.c

@@ -861,28 +861,30 @@ static int build_hosts(char const *syspath, char const *host, bool ata,
     return i;
 }
 
-/* Store disk device info specified by @sysfs into @fs */
+/*
-static void build_guest_fsinfo_for_real_device(char const *syspath,
+ * Store disk device info for devices on the PCI bus.
-                                               GuestFilesystemInfo *fs,
+ * Returns true if information has been stored, or false for failure.
-                                               Error **errp)
+ */
+static bool build_guest_fsinfo_for_pci_dev(char const *syspath,
+                                           GuestDiskAddress *disk,
+                                           Error **errp)
 {
     unsigned int pci[4], host, hosts[8], tgt[3];
     int i, nhosts = 0, pcilen;
-    GuestDiskAddress *disk;
+    GuestPCIAddress *pciaddr = disk->pci_controller;
-    GuestPCIAddress *pciaddr;
-    GuestDiskAddressList *list = NULL;
     bool has_ata = false, has_host = false, has_tgt = false;
     char *p, *q, *driver = NULL;
 #ifdef CONFIG_LIBUDEV
     struct udev *udev = NULL;
     struct udev_device *udevice = NULL;
 #endif
+    bool ret = false;
 
     p = strstr(syspath, "/devices/pci");
     if (!p || sscanf(p + 12, "%*x:%*x/%x:%x:%x.%x%n",
                      pci, pci + 1, pci + 2, pci + 3, &pcilen) < 4) {
         g_debug("only pci device is supported: sysfs path '%s'", syspath);
-        return;
+        return false;
     }
 
     p += 12 + pcilen;
@@ -903,7 +905,7 @@ static void build_guest_fsinfo_for_real_device(char const *syspath,
         }
 
         g_debug("unsupported driver or sysfs path '%s'", syspath);
-        return;
+        return false;
     }
 
     p = strstr(syspath, "/target");
@@ -929,18 +931,11 @@ static void build_guest_fsinfo_for_real_device(char const *syspath,
         }
     }
 
-    pciaddr = g_malloc0(sizeof(*pciaddr));
     pciaddr->domain = pci[0];
     pciaddr->bus = pci[1];
     pciaddr->slot = pci[2];
     pciaddr->function = pci[3];
 
-    disk = g_malloc0(sizeof(*disk));
-    disk->pci_controller = pciaddr;
-
-    list = g_malloc0(sizeof(*list));
-    list->value = disk;
-
 #ifdef CONFIG_LIBUDEV
     udev = udev_new();
     udevice = udev_device_new_from_syspath(udev, syspath);
@@ -1018,21 +1013,43 @@ static void build_guest_fsinfo_for_real_device(char const *syspath,
         goto cleanup;
     }
 
-    list->next = fs->disk;
+    ret = true;
-    fs->disk = list;
-    goto out;
 
 cleanup:
-    if (list) {
-        qapi_free_GuestDiskAddressList(list);
-    }
-out:
     g_free(driver);
 #ifdef CONFIG_LIBUDEV
     udev_unref(udev);
     udev_device_unref(udevice);
 #endif
-    return;
+    return ret;
+}
+
+/* Store disk device info specified by @sysfs into @fs */
+static void build_guest_fsinfo_for_real_device(char const *syspath,
+                                               GuestFilesystemInfo *fs,
+                                               Error **errp)
+{
+    GuestDiskAddress *disk;
+    GuestPCIAddress *pciaddr;
+    GuestDiskAddressList *list = NULL;
+    bool has_hwinf;
+
+    pciaddr = g_new0(GuestPCIAddress, 1);
+
+    disk = g_new0(GuestDiskAddress, 1);
+    disk->pci_controller = pciaddr;
+
+    list = g_new0(GuestDiskAddressList, 1);
+    list->value = disk;
+
+    has_hwinf = build_guest_fsinfo_for_pci_dev(syspath, disk, errp);
+
+    if (has_hwinf) {
+        list->next = fs->disk;
+        fs->disk = list;
+    } else {
+        qapi_free_GuestDiskAddressList(list);
+    }
 }
 
 static void build_guest_fsinfo_for_device(char const *devpath,