From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754705AbcBGTqz (ORCPT ); Sun, 7 Feb 2016 14:46:55 -0500 Received: from shards.monkeyblade.net ([149.20.54.216]:35945 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752918AbcBGTqy (ORCPT ); Sun, 7 Feb 2016 14:46:54 -0500 Date: Sun, 07 Feb 2016 14:46:48 -0500 (EST) Message-Id: <20160207.144648.750890874940574761.davem@davemloft.net> To: stephen@networkplumber.org Cc: jarod@redhat.com, linux-kernel@vger.kernel.org, edumazet@google.com, jiri@mellanox.com, daniel@iogearbox.net, tom@herbertland.com, j.vosburgh@gmail.com, vfalico@gmail.com, gospo@cumulusnetworks.com, netdev@vger.kernel.org Subject: Re: [PATCH net v3 2/4] net: add rx_nohandler stat counter From: David Miller In-Reply-To: <20160207113732.25a88cc4@xeon-e3> References: <1454370667-2328-1-git-send-email-jarod@redhat.com> <1454370667-2328-3-git-send-email-jarod@redhat.com> <20160207113732.25a88cc4@xeon-e3> X-Mailer: Mew version 6.7 on Emacs 24.5 / Mule 6.0 (HANACHIRUSATO) Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.5.12 (shards.monkeyblade.net [149.20.54.216]); Sun, 07 Feb 2016 11:46:53 -0800 (PST) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Stephen Hemminger Date: Sun, 7 Feb 2016 11:37:32 -0800 > On Mon, 1 Feb 2016 18:51:05 -0500 > Jarod Wilson wrote: > >> --- a/include/uapi/linux/if_link.h >> +++ b/include/uapi/linux/if_link.h >> @@ -35,6 +35,8 @@ struct rtnl_link_stats { >> /* for cslip etc */ >> __u32 rx_compressed; >> __u32 tx_compressed; >> + >> + __u32 rx_nohandler; /* dropped, no handler found */ >> }; >> >> /* The main device statistics structure */ >> @@ -68,6 +70,8 @@ struct rtnl_link_stats64 { >> /* for cslip etc */ >> __u64 rx_compressed; >> __u64 tx_compressed; >> + >> + __u64 rx_nohandler; /* dropped, no handler found */ >> }; > > Why was this userspace ABI change allowed? > The stats structure is exposed to user space via netlink > and changing the size of responses will break iproute2 commands. > > The code will be expecting one size and the response will vary and > break existing code. Yes, the code should check the size > of the response, but it doesn't and I am sure iproute2 is not > the only code that does this. Jarod, please look into this.