From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751580AbbCNE7h (ORCPT ); Sat, 14 Mar 2015 00:59:37 -0400 Received: from mail-ig0-f177.google.com ([209.85.213.177]:33253 "EHLO mail-ig0-f177.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750841AbbCNE7f (ORCPT ); Sat, 14 Mar 2015 00:59:35 -0400 Message-ID: <5503C03F.8020903@plumgrid.com> Date: Fri, 13 Mar 2015 21:59:43 -0700 From: Alexei Starovoitov User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.8; rv:31.0) Gecko/20100101 Thunderbird/31.5.0 MIME-Version: 1.0 To: Daniel Borkmann , "David S. Miller" CC: Thomas Graf , linux-api@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 net-next 1/2] bpf: allow extended BPF programs access skb fields References: <1426273064-4837-1-git-send-email-ast@plumgrid.com> <1426273064-4837-2-git-send-email-ast@plumgrid.com> <550392F7.9040308@iogearbox.net> <550397B0.5070409@iogearbox.net> <5503981C.6000801@plumgrid.com> <55039A0D.20000@iogearbox.net> <55039C9D.6010602@plumgrid.com> In-Reply-To: <55039C9D.6010602@plumgrid.com> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 3/13/15 7:27 PM, Alexei Starovoitov wrote: > On 3/13/15 7:16 PM, Daniel Borkmann wrote: >> On 03/14/2015 03:08 AM, Alexei Starovoitov wrote: >>> On 3/13/15 7:06 PM, Daniel Borkmann wrote: >>>> On 03/14/2015 02:46 AM, Daniel Borkmann wrote: >>>> ... >>>>> Previously, it was much more consistent, which I like better. And only >>>>> because of the simple BUILD_BUG_ON()? :/ >>>> >>>> Alternative is to move all of them into a central place, something like >>>> in twsk_build_assert() or __mld2_query_bugs[]. >>> >>> nope. that defeats the purpose of bug_on. >> >> Well, it doesn't. ;) It throws a build error thus the user is forced to >> investigate that further. > > according to this distorted logic all build_bug_on can be in one file > across the whole tree, since 'user is forced to investigate' ?! also note that this case and twsk_build_assert are different. twsk_build_assert has no other choice then to have one function that covers logic in the whole file, whereas in this patch: + BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, mark) != 4); + *insn++ = BPF_LDX_MEM(BPF_W, dst_reg, src_reg, + offsetof(struct sk_buff, mark)); the build_bug_on protect the line directly below. Separating them just doesn't make sense at all.