dm ioctl: introduce __get_dev_cell

Move logic to find device based on major/minor number to a separate
function __get_dev_cell (similar to __get_uuid_cell and __get_name_cell).
This makes the function __find_device_hash_cell more straightforward.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>

drivers/md/dm-ioctl.c

@@ -128,6 +128,24 @@ static struct hash_cell *__get_uuid_cell(const char *str)
 	return NULL;
 }
 
+static struct hash_cell *__get_dev_cell(uint64_t dev)
+{
+	struct mapped_device *md;
+	struct hash_cell *hc;
+
+	md = dm_get_md(huge_decode_dev(dev));
+	if (!md)
+		return NULL;
+
+	hc = dm_get_mdptr(md);
+	if (!hc) {
+		dm_put(md);
+		return NULL;
+	}
+
+	return hc;
+}
+
 /*-----------------------------------------------------------------
  * Inserting, removing and renaming a device.
  *---------------------------------------------------------------*/
@@ -718,34 +736,23 @@ static int dev_create(struct dm_ioctl *param, size_t param_size)
  */
 static struct hash_cell *__find_device_hash_cell(struct dm_ioctl *param)
 {
-	struct mapped_device *md;
 	struct hash_cell *hc = NULL;
 
 	if (*param->uuid) {
 		hc = __get_uuid_cell(param->uuid);
 		if (!hc)
 			return NULL;
-		goto fill_params;
-	}
-
-	if (*param->name) {
+	} else if (*param->name) {
 		hc = __get_name_cell(param->name);
 		if (!hc)
 			return NULL;
-		goto fill_params;
-	}
-
-	md = dm_get_md(huge_decode_dev(param->dev));
-	if (!md)
+	} else if (param->dev) {
+		hc = __get_dev_cell(param->dev);
+		if (!hc)
 			return NULL;
-
-	hc = dm_get_mdptr(md);
-	if (!hc) {
-		dm_put(md);
+	} else
 		return NULL;
-	}
 
-fill_params:
 	/*
 	 * Sneakily write in both the name and the uuid
 	 * while we have the cell.