From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andi Kleen Subject: Re: [PATCH] [13/21] Use blk_q_mask/get_pages_mask in sg driver Date: Mon, 17 Nov 2008 11:22:28 +0100 Message-ID: <20081117102227.GG6703@one.firstfloor.org> References: <20081115231113.8F2AF3E6618@basil.firstfloor.org> <491F8148.9000003@interlog.com> <20081116221722.GB6703@one.firstfloor.org> <20081117141240X.fujita.tomonori@lab.ntt.co.jp> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from one.firstfloor.org ([213.235.205.2]:34726 "EHLO one.firstfloor.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750922AbYKQKMw (ORCPT ); Mon, 17 Nov 2008 05:12:52 -0500 Content-Disposition: inline In-Reply-To: <20081117141240X.fujita.tomonori@lab.ntt.co.jp> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: FUJITA Tomonori Cc: andi@firstfloor.org, dgilbert@interlog.com, James.Bottomley@HansenPartnership.com, axboe@kernel.dk, linux-scsi@vger.kernel.org On Mon, Nov 17, 2008 at 02:11:51PM +0900, FUJITA Tomonori wrote: > On Sun, 16 Nov 2008 23:17:22 +0100 > Andi Kleen wrote: > > > On Sat, Nov 15, 2008 at 09:11:20PM -0500, Douglas Gilbert wrote: > > > Andi Kleen wrote: > > > >Instead of using GFP_DMA directly. > > > > > > > >Also I stubbed SG_SET_FORCE_LOW_DMA ioctls which don't make any sense > > > >because the kernel should always use the correct values on its own. > > > > > > You propose removing a define from a public interface and thereby > > > might break existing code. A comment in sg.h might be appropriate. > > > > Hmm, I assume those SG_SET_FORCE_* defines are only used > > in the kernel. > > I don't think so. They are exported to userspace, the sg ioctl > interface. There may be applications that use them. I doubt it. For what would they use it? And when exactly should an application know that some device has a 16MB limit when the kernel driver doesn't know about that? For me it looks more like a really old debugging interface. > Well, I don't think that they are useful or a nice feature. They would > become pointless when you finish your dma allocation rework. But I > don't think that we can remove the existing API exported to userspace. Ok I'll restore the defines. But readding the ioctls would be messy. Do you really think that is needed? I would rather prefer to fix the driver to always GFP_DMA, but I am not aware of any driver who needs it. Are you? -Andi