From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933510AbXIKJ0r (ORCPT ); Tue, 11 Sep 2007 05:26:47 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1762225AbXIKJ0k (ORCPT ); Tue, 11 Sep 2007 05:26:40 -0400 Received: from brick.kernel.dk ([87.55.233.238]:17234 "EHLO kernel.dk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759490AbXIKJ0j (ORCPT ); Tue, 11 Sep 2007 05:26:39 -0400 Date: Tue, 11 Sep 2007 11:35:11 +0200 From: Jens Axboe To: Paul Mundt , Andrew Morton , David Howells , Greg Ungerer , linux-kernel@vger.kernel.org Subject: Re: [PATCH -mm] splice: Disable vmsplice on nommu. Message-ID: <20070911093510.GA15405@kernel.dk> References: <20070911082307.GB19495@linux-sh.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20070911082307.GB19495@linux-sh.org> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Sep 11 2007, Paul Mundt wrote: > The vmsplice rework in -mm breaks nommu: > > fs/built-in.o: In function `splice_setup_vma': > fs/splice.c:1272: undefined reference to `may_expand_vm' > fs/splice.c:1272: undefined reference to `protection_map' > fs/splice.c:1272: undefined reference to `insert_vm_struct' > fs/splice.c:1272: undefined reference to `vm_stat_account' > > This is going to be non-trivial to wire up properly on nommu, and > it's debateable whether there's even any point in trying. For now, > disable vmsplice if CONFIG_MMU=n and wire it up as a cond syscall > for the platforms that support both. It's a bit of a sledge hammer... Since get_user_pages() appears to work on nummu, we can just disable the vmsplice-to-userspace bits and leave the (working) vmsplice-from-userspace in place. I'm reworking this code anyway in the block branches, so I'll update and take CONFIG_MMU into consideration. -- Jens Axboe