From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754125Ab0IDKNT (ORCPT ); Sat, 4 Sep 2010 06:13:19 -0400 Received: from pfepa.post.tele.dk ([195.41.46.235]:41217 "EHLO pfepa.post.tele.dk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753558Ab0IDKNS (ORCPT ); Sat, 4 Sep 2010 06:13:18 -0400 Date: Sat, 4 Sep 2010 12:13:13 +0200 From: Sam Ravnborg To: FUJITA Tomonori Cc: akpm@linux-foundation.org, miklos@szeredi.hu, jdike@addtoit.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH -mm] uml: disable CONFIG_HAS_DMA Message-ID: <20100904101313.GA26489@merkur.ravnborg.org> References: <20100904181622P.fujita.tomonori@lab.ntt.co.jp> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20100904181622P.fujita.tomonori@lab.ntt.co.jp> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Sep 04, 2010 at 06:17:56PM +0900, FUJITA Tomonori wrote: > I think that it's better to detect DMA misuse at build time rather > than calling BUG_ON. Architectures that can't do DMA need to disable > CONFIG_HAS_DMA. > > Signed-off-by: FUJITA Tomonori > --- > arch/um/Kconfig.um | 3 + > arch/um/defconfig | 1 - > arch/um/include/asm/dma-mapping.h | 112 ------------------------------------- > 3 files changed, 3 insertions(+), 113 deletions(-) > delete mode 100644 arch/um/include/asm/dma-mapping.h > > diff --git a/arch/um/Kconfig.um b/arch/um/Kconfig.um > index ec2b8da..3de40b8 100644 > --- a/arch/um/Kconfig.um > +++ b/arch/um/Kconfig.um > @@ -147,3 +147,6 @@ config KERNEL_STACK_ORDER > This option determines the size of UML kernel stacks. They will > be 1 << order pages. The default is OK unless you're running Valgrind > on UML, in which case, set this to 3. > + > +config HAS_DMA > + def_bool n Other archs define NO_DMA to say they do not have DMA. We should do it the same way for um. Sam