Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753810Ab3IJRQM (ORCPT ); Tue, 10 Sep 2013 13:16:12 -0400 Received: from mail-wi0-f171.google.com ([209.85.212.171]:33665 "EHLO mail-wi0-f171.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752728Ab3IJRQK (ORCPT ); Tue, 10 Sep 2013 13:16:10 -0400 MIME-Version: 1.0 In-Reply-To: References: <1378688580-11935-1-git-send-email-linux@roeck-us.net> <20130909015945.GA4029@kroah.com> <20130909134012.GA24738@infradead.org> <20130909163902.GA28685@kroah.com> <20130909170819.GA22764@roeck-us.net> <20130909172232.GA10029@kroah.com> <20130909200610.GA28416@roeck-us.net> From: Peng Tao Date: Wed, 11 Sep 2013 01:15:49 +0800 Message-ID: Subject: Re: [PATCH] staging: Disable lustre file system for MIPS, SH, and XTENSA To: Geert Uytterhoeven Cc: Guenter Roeck , Greg Kroah-Hartman , "David S. Miller" , Christoph Hellwig , "linux-kernel@vger.kernel.org" , driverdevel 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: 1814 Lines: 45 On Tue, Sep 10, 2013 at 4:49 PM, Geert Uytterhoeven wrote: > On Mon, Sep 9, 2013 at 10:06 PM, Guenter Roeck wrote: >>> [*] Why does m68k allmodconfig still succeed on kissb??? >>> It does fail for me, as m68k's copy_from_user_page() calls >>> flush_icache_user_range(), which is not exported. >>> >> I don't see a build failure in m68k:allmodconfig either. >> >> flush_icache_user_range() is called from copy_to_user_page(), not from >> copy_from_user_page(). copy_from_user_page() calls flush_cache_page() >> which calls __flush_cache_030(). The first is inline, the second is >> assembler, so I would expect it to work. Which doesn't answer >> the question why it fails for you. > > Sorry, I meant copy_to_user_page(). > > I tried with 2.6.3 from crosstool, and it succeeded, too. > > Turns out cfs_access_process_vm() is called with write=0 only. > Gcc 2.6.3 optimizes away the write != 0 branch (which calls copy_to_user_page() > and thus flush_icache_user_range()), while gcc 4.1.2 doesn't do that. > Mystery solved. > Thanks for chasing down the root cause. I was also wondering why I didn't see this when building on MIPS some time ago. Thanks, Tao > 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/