From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965471AbcCJJMN (ORCPT ); Thu, 10 Mar 2016 04:12:13 -0500 Received: from mout.kundenserver.de ([212.227.17.13]:62064 "EHLO mout.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S935229AbcCJJLx (ORCPT ); Thu, 10 Mar 2016 04:11:53 -0500 From: Arnd Bergmann To: Alexei Starovoitov Subject: Re: [PATCH] bpf: make bpf_stackmap_copy conditionally called Date: Thu, 10 Mar 2016 10:11:10 +0100 User-Agent: KMail/1.12.2 (Linux/3.19.0-54-generic; KDE/4.3.2; x86_64; ; ) Cc: Alexei Starovoitov , "David S. Miller" , Daniel Borkmann , netdev@vger.kernel.org, linux-kernel@vger.kernel.org References: <1457574245-2998842-1-git-send-email-arnd@arndb.de> <20160310033845.GA62491@ast-mbp.thefacebook.com> In-Reply-To: <20160310033845.GA62491@ast-mbp.thefacebook.com> MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Message-Id: <201603101011.11010.arnd@arndb.de> X-Provags-ID: V03:K0:5RfupMeJD5EnurVms4Lr8Lb1r8IGaWpfcMDbj3wNmBAD1l7KrOs J3kAmu7ElZMHFNnLB0x/F5iJoRF8kXhsfWrfHu74pjPTBxIx5KB0WTdeA93scKghHwVWYD9 aJE0bi1msfzS0V6vCluZdbFOgVqPGPOB9lToc7+pXJxv6nXv8FpdiMu/tFPMgsvGeHcFHfh MpDctaBx4RBrbp7Qc/IhQ== X-UI-Out-Filterresults: notjunk:1;V01:K0:7yOQ2Eb4lLk=:JdFW4SlE0dfe7V6Qaiwn6Y R6ctu/uThaFoI2VfNifYhWIWW0AsJifa6MdPo0pJ9IyZv4eo/5d6LwXp1LFchz0GNwkPvEKld +zMyuDS/5FYhg0nKOEPBrDBb0CiNdVGLsfsCrNEj4JymqhGoZ8yGCte8Kz3FMR9D/D4sur1Qb +z4vHXv/QTPB3CRdYjA8HN6Gai2EL0svXutD7U+3BjF9lPGcmzsSUKBVKx0ZzcY4zIXXV/4Ez jk6T66SiaI41Fwbj8LDnxBOJEmLUP5sruNjuBUjDZL6AwsfET6VjD/9ayu5NTgrEvbXL4rAq5 4H52G7Zi0o5GMjXXkUtz3duLEBgNX+zQWKYWYj1J6X75a3rk2LIn8qX4cs23nnBMtJOe/BwFz g4/KdUH7yC+jykFso3jjWQrDMQBcDuHnSXOq+jtQf7wRQvkY2n7E96Qu4+8hDhOry6kEA2kAE xNNlOs4rRR3/VTQ9qPavqFHAX09fjCuYo0TLloo/Huf7IKmdsaOT40zkLQ6ckj30I5tS1TEz6 WCUrpX6BaKhlUhd6bCauiPQ/4Gw/lDtd/tpsUZckeOAltABMqZiRFMs9cqk9oTlten2j0IdSL Q/da/1NSVaTcXJav55tP+ew5G32mw7/SROAINmxmLrbHltgBImNoi2LE2sf8VQENvdi9DLyYX FV/E18C42kFiNFCELN/K2ITqFVpAr7MGZt3lHud06ECZWBfSyiHexXhwiQM1z0p32pvKKgBqa iIgojzyWsjQwE7Xs Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thursday 10 March 2016, Alexei Starovoitov wrote: > yes. this is also ok-ish fix. > I've sent different version already: > http://patchwork.ozlabs.org/patch/595617/ > > I considered the option like yours but it's relying on gcc doing > dead code elimination of 'if (false) {}' branch and though kernel > is never compiled with -O0. I didn't want to take the risk. > I'm fine with either approach though. Ok, and I see yours is already applied, so that's fine. In general, I don't like __weak symbols in the kernel as they make it less clear what is actually getting called, and I think my version would have been safe, we rely on building with -O2 or -Os in a lot of places because of similar things. Arnd