commit 5420f26507fc5c9853eb1076401a8658d72669da
Author: Jim Fehlig <jfehlig@suse.com>
Date:   Fri Jan 11 12:22:26 2013 +0000

    libxl: Set vfb and vkb devid if not done so by the caller
    
    Other devices set a sensible devid if the caller has not done so.
    Do the same for vfb and vkb.  While at it, factor out the common code
    used to determine a sensible devid, so it can be used by other
    libxl__device_*_add functions.
    
    Signed-off-by: Jim Fehlig <jfehlig@suse.com>
    Acked-by: Ian Campbell <ian.campbell@citrix.com>
    Committed-by: Ian Campbell <ian.campbell@citrix.com>

Index: xen-4.2.2-testing/tools/libxl/libxl.c
===================================================================
--- xen-4.2.2-testing.orig/tools/libxl/libxl.c
+++ xen-4.2.2-testing/tools/libxl/libxl.c
@@ -1710,6 +1710,26 @@ out:
     return;
 }
 
+/* common function to get next device id */
+static int libxl__device_nextid(libxl__gc *gc, uint32_t domid, char *device)
+{
+    char *dompath, **l;
+    unsigned int nb;
+    int nextid = -1;
+
+    if (!(dompath = libxl__xs_get_dompath(gc, domid)))
+        return nextid;
+
+    l = libxl__xs_directory(gc, XBT_NULL,
+                            GCSPRINTF("%s/device/%s", dompath, device), &nb);
+    if (l == NULL || nb == 0)
+        nextid = 0;
+    else
+        nextid = strtoul(l[nb - 1], NULL, 10) + 1;
+
+    return nextid;
+}
+
 /******************************************************************************/
 
 int libxl__device_disk_setdefault(libxl__gc *gc, libxl_device_disk *disk)
@@ -2549,8 +2569,7 @@ void libxl__device_nic_add(libxl__egc *e
     flexarray_t *front;
     flexarray_t *back;
     libxl__device *device;
-    char *dompath, **l;
-    unsigned int nb, rc;
+    unsigned int rc;
 
     rc = libxl__device_nic_setdefault(gc, nic, domid);
     if (rc) goto out;
@@ -2567,17 +2586,10 @@ void libxl__device_nic_add(libxl__egc *e
     }
 
     if (nic->devid == -1) {
-        if (!(dompath = libxl__xs_get_dompath(gc, domid))) {
+        if ((nic->devid = libxl__device_nextid(gc, domid, "vif") < 0)) {
             rc = ERROR_FAIL;
             goto out_free;
         }
-        if (!(l = libxl__xs_directory(gc, XBT_NULL,
-                                     libxl__sprintf(gc, "%s/device/vif", dompath), &nb)) ||
-            nb == 0) {
-            nic->devid = 0;
-        } else {
-            nic->devid = strtoul(l[nb - 1], NULL, 10) + 1;
-        }
     }
 
     GCNEW(device);
@@ -2964,6 +2976,13 @@ int libxl__device_vkb_add(libxl__gc *gc,
         goto out_free;
     }
 
+    if (vkb->devid == -1) {
+        if ((vkb->devid = libxl__device_nextid(gc, domid, "vkb") < 0)) {
+            rc = ERROR_FAIL;
+            goto out_free;
+        }
+    }
+
     rc = libxl__device_from_vkb(gc, domid, vkb, &device);
     if (rc != 0) goto out_free;
 
@@ -3065,6 +3084,13 @@ int libxl__device_vfb_add(libxl__gc *gc,
         goto out_free;
     }
 
+    if (vfb->devid == -1) {
+        if ((vfb->devid = libxl__device_nextid(gc, domid, "vfb") < 0)) {
+            rc = ERROR_FAIL;
+            goto out_free;
+        }
+    }
+
     rc = libxl__device_from_vfb(gc, domid, vfb, &device);
     if (rc != 0) goto out_free;