From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932504AbcDVPmI (ORCPT ); Fri, 22 Apr 2016 11:42:08 -0400 Received: from host.76.145.23.62.rev.coltfrance.com ([62.23.145.76]:53662 "EHLO proxy.6wind.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932471AbcDVPmC (ORCPT ); Fri, 22 Apr 2016 11:42:02 -0400 From: Nicolas Dichtel To: netdev@vger.kernel.org Cc: davem@davemloft.net, linux-kernel@vger.kernel.org, linux-wpan@vger.kernel.org, aar@pengutronix.de, pablo@netfilter.org, kaber@trash.net, kadlec@blackhole.kfki.hu, pshelar@nicira.com, kuznet@ms2.inr.ac.ru, jmorris@namei.org, yoshfuji@linux-ipv6.org, netfilter-devel@vger.kernel.org, dev@openvswitch.org, steffen.klassert@secunet.com, herbert@gondor.apana.org.au, bsingharora@gmail.com, Nicolas Dichtel Subject: [PATCH net-next 9/9] taskstats: use the libnl API to align nlattr on 64-bit Date: Fri, 22 Apr 2016 17:31:24 +0200 Message-Id: <1461339084-3849-10-git-send-email-nicolas.dichtel@6wind.com> X-Mailer: git-send-email 2.8.1 In-Reply-To: <1461339084-3849-1-git-send-email-nicolas.dichtel@6wind.com> References: <1461339084-3849-1-git-send-email-nicolas.dichtel@6wind.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Goal of this patch is to use the new libnl API to align netlink attribute when needed. The layout of the netlink message will be a bit different after the patch, because the padattr (TASKSTATS_TYPE_STATS) will be inside the nested attribute instead of before it. Signed-off-by: Nicolas Dichtel --- kernel/taskstats.c | 37 +++++-------------------------------- 1 file changed, 5 insertions(+), 32 deletions(-) diff --git a/kernel/taskstats.c b/kernel/taskstats.c index 21f82c29c914..b3f05ee20d18 100644 --- a/kernel/taskstats.c +++ b/kernel/taskstats.c @@ -357,10 +357,6 @@ static int parse(struct nlattr *na, struct cpumask *mask) return ret; } -#if defined(CONFIG_64BIT) && !defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) -#define TASKSTATS_NEEDS_PADDING 1 -#endif - static struct taskstats *mk_reply(struct sk_buff *skb, int type, u32 pid) { struct nlattr *na, *ret; @@ -370,29 +366,6 @@ static struct taskstats *mk_reply(struct sk_buff *skb, int type, u32 pid) ? TASKSTATS_TYPE_AGGR_PID : TASKSTATS_TYPE_AGGR_TGID; - /* - * The taskstats structure is internally aligned on 8 byte - * boundaries but the layout of the aggregrate reply, with - * two NLA headers and the pid (each 4 bytes), actually - * force the entire structure to be unaligned. This causes - * the kernel to issue unaligned access warnings on some - * architectures like ia64. Unfortunately, some software out there - * doesn't properly unroll the NLA packet and assumes that the start - * of the taskstats structure will always be 20 bytes from the start - * of the netlink payload. Aligning the start of the taskstats - * structure breaks this software, which we don't want. So, for now - * the alignment only happens on architectures that require it - * and those users will have to update to fixed versions of those - * packages. Space is reserved in the packet only when needed. - * This ifdef should be removed in several years e.g. 2012 once - * we can be confident that fixed versions are installed on most - * systems. We add the padding before the aggregate since the - * aggregate is already a defined type. - */ -#ifdef TASKSTATS_NEEDS_PADDING - if (nla_put(skb, TASKSTATS_TYPE_NULL, 0, NULL) < 0) - goto err; -#endif na = nla_nest_start(skb, aggr); if (!na) goto err; @@ -401,7 +374,8 @@ static struct taskstats *mk_reply(struct sk_buff *skb, int type, u32 pid) nla_nest_cancel(skb, na); goto err; } - ret = nla_reserve(skb, TASKSTATS_TYPE_STATS, sizeof(struct taskstats)); + ret = nla_reserve_64bit(skb, TASKSTATS_TYPE_STATS, + sizeof(struct taskstats), TASKSTATS_TYPE_NULL); if (!ret) { nla_nest_cancel(skb, na); goto err; @@ -500,10 +474,9 @@ static size_t taskstats_packet_size(void) size_t size; size = nla_total_size(sizeof(u32)) + - nla_total_size(sizeof(struct taskstats)) + nla_total_size(0); -#ifdef TASKSTATS_NEEDS_PADDING - size += nla_total_size(0); /* Padding for alignment */ -#endif + nla_total_size_64bit(sizeof(struct taskstats)) + + nla_total_size(0); + return size; } -- 2.8.1