Unregister watch in error path.

Signed-off-by: Christian Limpach <Christian.Limpach@cl.cam.ac.uk>

diff --git a/linux-2.6-xen-sparse/drivers/xen/blkback/xenbus.c b/linux-2.6-xen-sparse/drivers/xen/blkback/xenbus.c
index 2a445a39838faffe3762ecda84f66bef119891e8..9d255aefd893b414e149e30112e5f765a6c2cea0 100644 (file)
--- a/linux-2.6-xen-sparse/drivers/xen/blkback/xenbus.c
+++ b/linux-2.6-xen-sparse/drivers/xen/blkback/xenbus.c
@@ -201,21 +201,8 @@ static int blkback_probe(struct xenbus_device *dev,
                xenbus_dev_error(dev, -ENOMEM, "allocating backend structure");
                return -ENOMEM;
        }
-
        memset(be, 0, sizeof(*be));
 
-       be->dev = dev;
-       be->backend_watch.node = dev->nodename;
-       be->backend_watch.callback = backend_changed;
-       err = register_xenbus_watch(&be->backend_watch);
-       if (err) {
-               xenbus_dev_error(dev, err, "adding backend watch on %s",
-                                dev->nodename);
-               goto free_be;
-       }
-
-       dev->data = be;
-
        frontend = NULL;
        err = xenbus_gather(dev->nodename,
                            "frontend-id", "%li", &be->frontend_id,
@@ -223,17 +210,28 @@ static int blkback_probe(struct xenbus_device *dev,
                            NULL);
        if (XENBUS_EXIST_ERR(err))
                goto free_be;
-       if (frontend &&
-           (strlen(frontend) == 0 || !xenbus_exists(frontend, ""))) {
+       if (err < 0) {
+               xenbus_dev_error(dev, err,
+                                "reading %s/frontend or frontend-id",
+                                dev->nodename);
+               goto free_be;
+       }
+       if (strlen(frontend) == 0 || !xenbus_exists(frontend, "")) {
                /* If we can't get a frontend path and a frontend-id,
                 * then our bus-id is no longer valid and we need to
                 * destroy the backend device.
                 */
+               err = -ENOENT;
                goto free_be;
        }
-       if (err < 0) {
-               xenbus_dev_error(dev, err,
-                                "reading %s/frontend or frontend-id",
+
+       be->dev = dev;
+       be->backend_watch.node = dev->nodename;
+       be->backend_watch.callback = backend_changed;
+       err = register_xenbus_watch(&be->backend_watch);
+       if (err) {
+               be->backend_watch.node = NULL;
+               xenbus_dev_error(dev, err, "adding backend watch on %s",
                                 dev->nodename);
                goto free_be;
        }
@@ -250,10 +248,14 @@ static int blkback_probe(struct xenbus_device *dev,
                goto free_be;
        }
 
+       dev->data = be;
+
        backend_changed(&be->backend_watch, dev->nodename);
-       return err;
+       return 0;
 
  free_be:
+       if (be->backend_watch.node)
+               unregister_xenbus_watch(&be->backend_watch);
        if (frontend)
                kfree(frontend);
        kfree(be);