From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S264537AbTLVWXg (ORCPT ); Mon, 22 Dec 2003 17:23:36 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S264538AbTLVWXg (ORCPT ); Mon, 22 Dec 2003 17:23:36 -0500 Received: from fw.osdl.org ([65.172.181.6]:63131 "EHLO mail.osdl.org") by vger.kernel.org with ESMTP id S264537AbTLVWXe (ORCPT ); Mon, 22 Dec 2003 17:23:34 -0500 Date: Mon, 22 Dec 2003 14:24:26 -0800 From: Andrew Morton To: Joe Korty Cc: rml@ximian.com, wli@holomorphy.com, albert@users.sourceforge.net, linux-kernel@vger.kernel.org Subject: Re: atomic copy_from_user? Message-Id: <20031222142426.24c8951e.akpm@osdl.org> In-Reply-To: <20031222215933.GA3189@rudolph.ccur.com> References: <1072054100.1742.156.camel@cube> <20031222150026.GD27687@holomorphy.com> <20031222182637.GA2659@rudolph.ccur.com> <1072126506.3318.31.camel@fur> <20031222212237.GA2865@rudolph.ccur.com> <1072129210.3318.34.camel@fur> <20031222215933.GA3189@rudolph.ccur.com> X-Mailer: Sylpheed version 0.9.7 (GTK+ 1.2.10; i586-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Joe Korty wrote: > > > inc_preempt_count() and dec_preempt_count() are for use when you > > _absolutely_ must manage the preemption counter, regardless of whether > > or not kernel preemption is enabled. > > > > They are used for things like atomic kmaps. > > Hi Robert, > I do not see why a non-preempt kernel would care at all about > the value of preempt_count. (kmap_atomic is obviously setting it, > where is the place in a non-preempt kernel where the set value > is being acted upon?). do_page_fault()'s in_atomic() test.