From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933217AbcA3STt (ORCPT ); Sat, 30 Jan 2016 13:19:49 -0500 Received: from mx1.redhat.com ([209.132.183.28]:57721 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932418AbcA3STr (ORCPT ); Sat, 30 Jan 2016 13:19:47 -0500 From: Jarod Wilson To: linux-kernel@vger.kernel.org Cc: Jarod Wilson , Eric Dumazet , netdev@vger.kernel.org Subject: [PATCH net v2 1/4] net/core: relax BUILD_BUG_ON in netdev_stats_to_stats64 Date: Sat, 30 Jan 2016 13:19:42 -0500 Message-Id: <1454177982-32870-1-git-send-email-jarod@redhat.com> In-Reply-To: <1453996188-29965-1-git-send-email-jarod@redhat.com> References: <1453996188-29965-1-git-send-email-jarod@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The netdev_stats_to_stats64 function copies the deprecated net_device_stats format stats into rtnl_link_stats64 for legacy support purposes, but with the BUILD_BUG_ON as it was, it wasn't possible to extend rtnl_link_stats64 without also extending net_device_stats. Relax the BUILD_BUG_ON to only require that rtnl_link_stats64 is larger, and zero out all the stat counters that aren't present in net_device_stats. CC: Eric Dumazet CC: netdev@vger.kernel.org Signed-off-by: Jarod Wilson --- Re-re-sending, hopefully getting the patch to the right list this time. net/core/dev.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) diff --git a/net/core/dev.c b/net/core/dev.c index 8cba3d8..575a7df 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -7253,25 +7253,30 @@ void netdev_run_todo(void) } } -/* Convert net_device_stats to rtnl_link_stats64. They have the same - * fields in the same order, with only the type differing. +/* Convert net_device_stats to rtnl_link_stats64. rtnl_link_stats64 has + * all the same fields in the same order as net_device_stats, with only + * the type differing, but rtnl_link_stats64 may have additional fields + * at the end for newer counters. */ void netdev_stats_to_stats64(struct rtnl_link_stats64 *stats64, const struct net_device_stats *netdev_stats) { #if BITS_PER_LONG == 64 - BUILD_BUG_ON(sizeof(*stats64) != sizeof(*netdev_stats)); + BUILD_BUG_ON(sizeof(*stats64) < sizeof(*netdev_stats)); memcpy(stats64, netdev_stats, sizeof(*stats64)); #else size_t i, n = sizeof(*stats64) / sizeof(u64); const unsigned long *src = (const unsigned long *)netdev_stats; u64 *dst = (u64 *)stats64; - BUILD_BUG_ON(sizeof(*netdev_stats) / sizeof(unsigned long) != + BUILD_BUG_ON(sizeof(*netdev_stats) / sizeof(unsigned long) > sizeof(*stats64) / sizeof(u64)); for (i = 0; i < n; i++) dst[i] = src[i]; #endif + /* zero out counters that only exist in rtnl_link_stats64 */ + memset((char *)stats64 + sizeof(*netdev_stats), 0, + sizeof(*stats64) - sizeof(*netdev_stats)); } EXPORT_SYMBOL(netdev_stats_to_stats64); -- 1.8.3.1