Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262588AbUJ0Sxx (ORCPT ); Wed, 27 Oct 2004 14:53:53 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262568AbUJ0Sxk (ORCPT ); Wed, 27 Oct 2004 14:53:40 -0400 Received: from holomorphy.com ([207.189.100.168]:8321 "EHLO holomorphy.com") by vger.kernel.org with ESMTP id S262637AbUJ0StU (ORCPT ); Wed, 27 Oct 2004 14:49:20 -0400 Date: Wed, 27 Oct 2004 11:48:36 -0700 From: William Lee Irwin III To: Jeff Garzik Cc: Christoph Hellwig , Linux Kernel , linux-mm@kvack.org, Bartlomiej Zolnierkiewicz , "Randy.Dunlap" , Jens Axboe , James Bottomley Subject: Re: news about IDE PIO HIGHMEM bug Message-ID: <20041027184836.GA12934@holomorphy.com> References: <58cb370e041027074676750027@mail.gmail.com> <417FBB6D.90401@pobox.com> <1246230000.1098892359@[10.10.2.4]> <1246750000.1098892883@[10.10.2.4]> <20041027180816.GA32436@infradead.org> <417FEA09.6080502@pobox.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <417FEA09.6080502@pobox.com> Organization: The Domain of Holomorphy User-Agent: Mutt/1.5.6+20040722i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1066 Lines: 24 Christoph Hellwig wrote: >> I think this is the wrong level of interface exposed. Just add two hepler >> kmap_atomic_sg/kunmap_atomic_sg that gurantee to map/unmap a sg list entry, >> even if it's bigger than a page. On Wed, Oct 27, 2004 at 02:33:45PM -0400, Jeff Garzik wrote: > Why bother mapping anything larger than a page, when none of the users > need it? > P.S. In your scheme you would need four helpers; you forgot kmap_sg() > and kunmap_sg(). This is all a non-issue. The page structure just represents little more than a physical address to the block layer in the context of merging, so the pfn_to_page(page_to_pfn(...) + ...) bits calculate this properly. There is just nothing interesting going on here. Generate the page structure for the piece of the segment, kmap_atomic() it, and it's done. -- wli - 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/