From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Dumazet Subject: Re: [E1000-devel] [next:akpm 16/587] drivers/net/ethernet/intel/igb/igb_main.c:6231:2: error: call to '__compiletime_assert_6235' declared with attribute error: BUILD_BUG_ON failed: SKB_WITH_OVERHEAD(IGB_RX_BUFSZ) < (NET_SKB_PAD + NET_IP_ALIGN + IGB_TS_HDR_LEN + ETH... Date: Wed, 20 Feb 2013 13:42:40 -0800 Message-ID: <1361396560.19353.226.camel@edumazet-glaptop> References: <5122101a.nBjTqFyZXZ+WuzPr%fengguang.wu@intel.com> <20130219142708.b454d98a.akpm@linux-foundation.org> <804857E1F29AAC47BF68C404FC60A1844D0099DF@ORSMSX102.amr.corp.intel.com> <51251303.9030803@intel.com> <1361388156.19353.216.camel@edumazet-glaptop> <51253ED2.3050605@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: "Allan, Bruce W" , "e1000-devel@lists.sourceforge.net" , "netdev@vger.kernel.org" , "Brandeburg, Jesse" , Daniel Santos , Andrew Morton , "Wu, Fengguang" To: Alexander Duyck Return-path: Received: from mail-da0-f42.google.com ([209.85.210.42]:62448 "EHLO mail-da0-f42.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750977Ab3BTVmn (ORCPT ); Wed, 20 Feb 2013 16:42:43 -0500 Received: by mail-da0-f42.google.com with SMTP id z17so3761066dal.15 for ; Wed, 20 Feb 2013 13:42:43 -0800 (PST) In-Reply-To: <51253ED2.3050605@intel.com> Sender: netdev-owner@vger.kernel.org List-ID: On Wed, 2013-02-20 at 13:23 -0800, Alexander Duyck wrote: > NET_SKB_PAD is defined for the s390. It is already 32. If you look it > up we only have 2 definitions for NET_SKB_PAD, one specific to the s390 > architecture and the other one in skbuff.h. > Andrew traces disagree, as they were : >>> s390 allmodconfig: >>> >>> bool __cond = !(!(((2048) - (((sizeof(struct skb_shared_info)) + (256 - 1)) & >>> ~(256 - 1))) < (32 + 2 + 16 + 1514 + 4))); >>> So it might be only a cross-compile environment issue, I dont know. > From what I can tell we would have to drop the NET_SKB_PAD to 0 in order > to not trigger this error with igb since we still have to add 22 bytes > for igb's per packet timestamp header, IP alignment, and CRC. > > The simple fix is for us just to drop the BUILD_BUG_ON check for igb > since we already had a check for size check in igb_set_rx_buffer_len. > It just means that build_skb won't be available for standard MTU sizes > on s390. Yeah, probably nobody will notice ;)