rbd: consolidate rbd_dev init in rbd_add()

Group the allocation and initialization of fields of the rbd device
structure created in rbd_add().  Move the grouped code down later in
the function, just prior to the call to rbd_dev_probe().  This is
for the most part simple code movement.

Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>

drivers/block/rbd.c

@@ -3232,29 +3232,16 @@ static ssize_t rbd_add(struct bus_type *bus,
 	if (!try_module_get(THIS_MODULE))
 		return -ENODEV;
 
-	rbd_dev = kzalloc(sizeof(*rbd_dev), GFP_KERNEL);
-	if (!rbd_dev)
-		return -ENOMEM;
-
-	/* static rbd_device initialization */
-	spin_lock_init(&rbd_dev->lock);
-	INIT_LIST_HEAD(&rbd_dev->node);
-	INIT_LIST_HEAD(&rbd_dev->snaps);
-	init_rwsem(&rbd_dev->header_rwsem);
-
 	/* parse add command */
 	rc = rbd_add_parse_args(buf, &ceph_opts, &rbd_opts, &spec);
 	if (rc < 0)
-		goto err_out_mem;
+		goto err_out_module;
-
-	rbd_dev->mapping.read_only = rbd_opts->read_only;
 
 	rbdc = rbd_get_client(ceph_opts);
 	if (IS_ERR(rbdc)) {
 		rc = PTR_ERR(rbdc);
 		goto err_out_args;
 	}
-	rbd_dev->rbd_client = rbdc;
 	ceph_opts = NULL;	/* ceph_opts now owned by rbd_dev client */
 
 	/* pick the pool */
@@ -3264,11 +3251,22 @@ static ssize_t rbd_add(struct bus_type *bus,
 		goto err_out_client;
 	spec->pool_id = (u64) rc;
 
+	rbd_dev = kzalloc(sizeof (*rbd_dev), GFP_KERNEL);
+	if (!rbd_dev)
+		goto err_out_client;
+
+	spin_lock_init(&rbd_dev->lock);
+	INIT_LIST_HEAD(&rbd_dev->node);
+	INIT_LIST_HEAD(&rbd_dev->snaps);
+	init_rwsem(&rbd_dev->header_rwsem);
+	rbd_dev->rbd_client = rbdc;
 	rbd_dev->spec = spec;
 
+	rbd_dev->mapping.read_only = rbd_opts->read_only;
+
 	rc = rbd_dev_probe(rbd_dev);
 	if (rc < 0)
-		goto err_out_client;
+		goto err_out_mem;
 
 	/* no need to lock here, as rbd_dev is not registered yet */
 	rc = rbd_dev_snaps_update(rbd_dev);
@@ -3348,19 +3346,20 @@ err_out_snaps:
 	rbd_remove_all_snaps(rbd_dev);
 err_out_probe:
 	rbd_header_free(&rbd_dev->header);
-err_out_client:
 	kfree(rbd_dev->header_name);
+err_out_mem:
+	kfree(rbd_dev);
+err_out_client:
 	rbd_put_client(rbdc);
 err_out_args:
 	if (ceph_opts)
 		ceph_destroy_options(ceph_opts);
 	kfree(rbd_opts);
 	rbd_spec_put(spec);
-err_out_mem:
+err_out_module:
-	kfree(rbd_dev);
+	module_put(THIS_MODULE);
 
 	dout("Error adding device %s\n", buf);
-	module_put(THIS_MODULE);
 
 	return (ssize_t) rc;
 }