Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754999Ab3EMTQJ (ORCPT ); Mon, 13 May 2013 15:16:09 -0400 Received: from mail-ie0-f171.google.com ([209.85.223.171]:48183 "EHLO mail-ie0-f171.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753994Ab3EMTQH (ORCPT ); Mon, 13 May 2013 15:16:07 -0400 MIME-Version: 1.0 In-Reply-To: <1368472300.3305.39.camel@bwh-desktop.uk.solarflarecom.com> References: <1368467297.3305.28.camel@bwh-desktop.uk.solarflarecom.com> <1368472300.3305.39.camel@bwh-desktop.uk.solarflarecom.com> Date: Mon, 13 May 2013 21:16:06 +0200 X-Google-Sender-Auth: UhKdEzifVf-lpCCJ_ur-F9zjG_U Message-ID: Subject: Re: [PATCH net] sfc: Reduce RX scatter buffer size to multiple of 256 From: Geert Uytterhoeven To: Ben Hutchings Cc: David Miller , Heiko Carstens , Solarflare linux maintainers , Linux Kernel Development , linux-s390@vger.kernel.org, "netdev@vger.kernel.org" Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1309 Lines: 37 On Mon, May 13, 2013 at 9:11 PM, Ben Hutchings wrote: >> error: BUILD_BUG_ON failed: sizeof(struct efx_rx_page_state) + >> EFX_PAGE_IP_ALIGN + EFX_RX_USR_BUF_SIZE > PAGE_SIZE / 2 >> make[4]: *** [drivers/net/ethernet/sfc/efx.o] Error 1 > > OK, this doesn't work because on s390 EFX_PAGE_IP_ALIGN == 2 (this macro Yeah, that's what I just discovered, too. #ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS #define EFX_PAGE_IP_ALIGN 0 #else #define EFX_PAGE_IP_ALIGN NET_IP_ALIGN #endif > is equivalent to NET_IP_ALIGN, though that wasn't always true). So DMA > is going to be misaligned on s390 anyway. Hmm, so it's making the choice between misaligned CPU and misaligned DMA? Sounds fishy... Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/