Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751103AbWJET5S (ORCPT ); Thu, 5 Oct 2006 15:57:18 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751110AbWJET5R (ORCPT ); Thu, 5 Oct 2006 15:57:17 -0400 Received: from cantor.suse.de ([195.135.220.2]:49039 "EHLO mx1.suse.de") by vger.kernel.org with ESMTP id S1751103AbWJET5Q (ORCPT ); Thu, 5 Oct 2006 15:57:16 -0400 To: Andrew Morton Cc: Joe Korty , Inaky Perez-Gonzalez , Paul Jackson , linux-kernel@vger.kernel.org Subject: Re: [PATCH] bitmap: separate bitmap parsing for user buffer and kernel buffer References: <200610041756.30528.reinette.chatre@linux.intel.com> <20061004181003.6dae6065.akpm@osdl.org> From: Andi Kleen Date: 05 Oct 2006 21:57:04 +0200 In-Reply-To: <20061004181003.6dae6065.akpm@osdl.org> Message-ID: User-Agent: Gnus/5.09 (Gnus v5.9.0) Emacs/21.3 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 808 Lines: 19 Andrew Morton writes: > On Wed, 4 Oct 2006 17:56:30 -0700 > Reinette Chatre wrote: > > > + if (is_user) { > > + if (__get_user(c, buf++)) > > + return -EFAULT; > > + } > > + else > > + c = *buf++; > > Is this actually needed? __get_user(kernel_address) works OK and (believe > it or not, given all the stuff it involves) boils down to a single instruction. It is needed on lots of architectures that use separate address spaces like sparc64, m68k, s390 (and on x86 with 4:4 patches) -Andi - 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/