i40e: Move the mutex lock in i40e_client_unregister

We need to lock the client list around the i40e_client_release call to
prevent the release from interrupting the client instances while they are
being added.

Change-Id: I99993f20179aaf8730207833e7d0869d2ccffa1d
Signed-off-by: Catherine Sullivan <catherine.sullivan@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

drivers/net/ethernet/intel/i40e/i40e_client.c

@@ -980,13 +980,13 @@ int i40e_unregister_client(struct i40e_client *client)
 	 * a close for each of the client instances that were opened.
 	 * client_release function is called to handle this.
 	 */
+	mutex_lock(&i40e_client_mutex);
 	if (!client || i40e_client_release(client)) {
 		ret = -EIO;
 		goto out;
 	}
 
 	/* TODO: check if device is in reset, or if that matters? */
-	mutex_lock(&i40e_client_mutex);
 	if (!i40e_client_is_registered(client)) {
 		pr_info("i40e: Client %s has not been registered\n",
 			client->name);
@@ -1005,8 +1005,8 @@ int i40e_unregister_client(struct i40e_client *client)
 		       client->name);
 	}
 
-	mutex_unlock(&i40e_client_mutex);
 out:
+	mutex_unlock(&i40e_client_mutex);
 	return ret;
 }
 EXPORT_SYMBOL(i40e_unregister_client);