From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Wed, 27 Oct 2004 11:48:36 -0700 From: William Lee Irwin III 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> Sender: owner-linux-mm@kvack.org Return-Path: To: Jeff Garzik Cc: Christoph Hellwig , Linux Kernel , linux-mm@kvack.org, Bartlomiej Zolnierkiewicz , "Randy.Dunlap" , Jens Axboe , James Bottomley List-ID: 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, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: aart@kvack.org