From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jiri Pirko Subject: Re: [PATCH net-next v11 1/4] net netlink: Add new type NLA_BITFIELD_32 Date: Fri, 28 Jul 2017 16:08:40 +0200 Message-ID: <20170728140840.GC1857@nanopsycho> References: <1500860146-26970-1-git-send-email-jhs@emojatatu.com> <1500860146-26970-2-git-send-email-jhs@emojatatu.com> <1a2578ca-35c6-884e-1daf-fcc47e5eb618@gmail.com> <7c17a575-53bb-1f25-4a9a-7418f99660f2@mojatatu.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: David Ahern , davem@davemloft.net, netdev@vger.kernel.org, xiyou.wangcong@gmail.com, eric.dumazet@gmail.com, mrv@mojatatu.com, simon.horman@netronome.com, alex.aring@gmail.com To: Jamal Hadi Salim Return-path: Received: from mail-wr0-f195.google.com ([209.85.128.195]:34744 "EHLO mail-wr0-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751804AbdG1OIn (ORCPT ); Fri, 28 Jul 2017 10:08:43 -0400 Received: by mail-wr0-f195.google.com with SMTP id o33so19159287wrb.1 for ; Fri, 28 Jul 2017 07:08:43 -0700 (PDT) Content-Disposition: inline In-Reply-To: <7c17a575-53bb-1f25-4a9a-7418f99660f2@mojatatu.com> Sender: netdev-owner@vger.kernel.org List-ID: Fri, Jul 28, 2017 at 03:51:41PM CEST, jhs@mojatatu.com wrote: >On 17-07-25 10:41 AM, David Ahern wrote: >> On 7/23/17 7:35 PM, Jamal Hadi Salim wrote: >> > In the most basic form, the user specifies the attribute policy as: >> > [ATTR_GOO] = { .type = NLA_BITFIELD_32, .validation_data = &myvalidflags }, >> > >> > where myvalidflags is the bit mask of the flags the kernel understands. >> > >> > If the user _does not_ provide myvalidflags then the attribute will >> > also be rejected. >> >> No other netlink attribute has this requirement. > >This is the first one where we have to inspect content. We add things >when we need them - as in this case. > >> Users of the attributes >> are the only ones that know if a value is valid or not (e.g, attribute >> passing a device index) and those are always checked in line. > >It doesnt make sense that every user of the API has to repeat that >validation code. Same principle as someone specifying that a type is >u32 and have the nla validation check it. At some point we never had >the u32 validation code. Then it was factored out because everyone >repeats the same boilerplate code. >I see this in the same spirit. Agreed.