From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S265174AbUEYWa0 (ORCPT ); Tue, 25 May 2004 18:30:26 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S265140AbUEYW1K (ORCPT ); Tue, 25 May 2004 18:27:10 -0400 Received: from fw.osdl.org ([65.172.181.6]:59031 "EHLO mail.osdl.org") by vger.kernel.org with ESMTP id S265238AbUEYWY1 (ORCPT ); Tue, 25 May 2004 18:24:27 -0400 Date: Tue, 25 May 2004 15:24:12 -0700 (PDT) From: Linus Torvalds To: Benjamin Herrenschmidt cc: "David S. Miller" , wesolows@foobazco.org, willy@debian.org, Andrea Arcangeli , Andrew Morton , Linux Kernel list , mingo@elte.hu, bcrl@kvack.org, linux-mm@kvack.org, Linux Arch list Subject: Re: [PATCH] ppc64: Fix possible race with set_pte on a present PTE In-Reply-To: <1085523563.15281.136.camel@gaston> Message-ID: References: <1085369393.15315.28.camel@gaston> <1085371988.15281.38.camel@gaston> <1085373839.14969.42.camel@gaston> <20040525034326.GT29378@dualathlon.random> <20040525114437.GC29154@parcelfarce.linux.theplanet.co.uk> <20040525153501.GA19465@foobazco.org> <20040525102547.35207879.davem@redhat.com> <20040525105442.2ebdc355.davem@redhat.com> <1085521251.24948.127.camel@gaston> <1085523563.15281.136.camel@gaston> 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 On Wed, 26 May 2004, Benjamin Herrenschmidt wrote: > > > > So I think the code needs to invalidate the hash after having updated the > > pte. No? > > No, we'll take a hash fault, not a page fault. The hash fault is an asm > fast path, which in this case, will update the HPTE RW permission when > the PTE has PAGE_RW (and will set PAGE_DIRTY again, but that's fine). Ahh. Goodie. Then the "simple" atomic bitset probably works. Assuming I translated the asm/atomic.h stuff correctly. Linus