Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755136Ab1BMWBs (ORCPT ); Sun, 13 Feb 2011 17:01:48 -0500 Received: from earthlight.etchedpixels.co.uk ([81.2.110.250]:38237 "EHLO www.etchedpixels.co.uk" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1754947Ab1BMWBm (ORCPT ); Sun, 13 Feb 2011 17:01:42 -0500 Date: Sun, 13 Feb 2011 22:06:08 +0000 From: Alan Cox To: Nikolaus Rath Cc: Brice Goglin , LKML Subject: Re: virt_to_page for userspace pointers Message-ID: <20110213220608.0c4b0cc2@lxorguk.ukuu.org.uk> In-Reply-To: <4D58537C.3020409@rath.org> References: <87k4hgn8qa.fsf@inspiron.ap.columbia.edu> <878vxuxkfr.fsf@inspiron.ap.columbia.edu> <4D4DC2D6.8030905@ens-lyon.org> <4D583E17.80606@rath.org> <4D5840F6.8030401@ens-lyon.org> <4D58537C.3020409@rath.org> X-Mailer: Claws Mail 3.7.8 (GTK+ 2.22.0; x86_64-redhat-linux-gnu) Face: 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 Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 693 Lines: 16 > > If you don't lock the page, you have no guarantee that it won't get > > swapped out or migrated while you look at the physical page. > > That's fine, I know that if the page is there at all then it has been > locked by a (different) kernel driver. Is there any way to find out what > I want? How do you know the other driver isn't in the middle of releasing the page ? Doing that deep in mm code without locking inversions will be fun. Alan -- 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/