From: Badari Pulavarty Subject: Re: [PATCH] direct-IO API change Date: Fri, 4 Oct 2002 16:56:45 -0700 (PDT) Sender: nfs-admin@lists.sourceforge.net Message-ID: <200210042356.g94NujG24693@eng2.beaverton.ibm.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: akpm@digeo.com (Andrew Morton), pbadari@us.ibm.com (Badari Pulavarty), janetmor@us.ibm.com (Janet Morgan), cel@citi.umich.edu (Chuck Lever), linux-kernel@vger.kernel.org (Linux Kernel Mailing List), nfs@lists.sourceforge.net (Linux NFS List) Return-path: Received: from e2.ny.us.ibm.com ([32.97.182.102]) by usw-sf-list1.sourceforge.net with esmtp (Cipher TLSv1:DES-CBC3-SHA:168) (Exim 3.31-VA-mm2 #1 (Debian)) id 17xcJd-0007j8-00 for ; Fri, 04 Oct 2002 16:57:05 -0700 To: torvalds@transmeta.com (Linus Torvalds) In-Reply-To: from "Linus Torvalds" at Oct 04, 2002 03:44:46 PM PST Errors-To: nfs-admin@lists.sourceforge.net List-Help: List-Post: List-Subscribe: , List-Id: Discussion of NFS under Linux development, interoperability, and testing. List-Unsubscribe: , List-Archive: > > > On Fri, 4 Oct 2002, Andrew Morton wrote: > > > > > Especially since I thought that O_DIRECT on the regular file (or block > > > device) performed about as well as raw does anyway these days? Or is that > > > just one of my LSD-induced flashbacks? > > > > > > > Now we're not holding i_sem for O_DIRECT writes to blockdevs, > > I don't think the raw driver offers any advantages at all. It's > > a compatibility thing to save people from having to add "|O_DIRECT" to > > their source and then typing `ln -s /dev/hda1 /dev/raw/raw0'. > > Maybe the raw driver could become a shell that just adds the O_DIRECT? > Unless it can do something more, of course.. > > Linus > > Only issue would be the alignment restriction on blockdev versus raw device. raw allows 512 byte alignment on userbuff, offset and length. blockdevice might need 1024/2048 byte alignment. If we get the alignment patch for DIO, this is not an issue. (alignment patch - in case of defualt alignment problem, go down to blkdev_hardsect_size() alignment.) - Badari ------------------------------------------------------- This sf.net email is sponsored by:ThinkGeek Welcome to geek heaven. http://thinkgeek.com/sf _______________________________________________ NFS maillist - NFS@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/nfs