Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758738AbXK1IKe (ORCPT ); Wed, 28 Nov 2007 03:10:34 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753026AbXK1IKY (ORCPT ); Wed, 28 Nov 2007 03:10:24 -0500 Received: from mx1.riseup.net ([204.13.164.18]:34634 "EHLO mx1.riseup.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751726AbXK1IKY (ORCPT ); Wed, 28 Nov 2007 03:10:24 -0500 Date: Wed, 28 Nov 2007 09:10:31 +0100 From: Matthias Kaehlcke To: Larry Finger Cc: LKML Subject: Re: Question regarding mutex locking Message-ID: <20071128081031.GF20238@traven> Mail-Followup-To: Matthias Kaehlcke , Larry Finger , LKML References: <474CF06C.8020208@lwfinger.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <474CF06C.8020208@lwfinger.net> User-Agent: Mutt/1.5.16 (2007-06-11) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1180 Lines: 33 El Tue, Nov 27, 2007 at 10:37:00PM -0600 Larry Finger ha dit: > If a particular routine needs to lock a mutex, but it may be entered with that mutex already locked, > would the following code be SMP safe? > > hold_lock = mutex_trylock() > > ... > > if (hold_lock) > mutex_unlock() this is wont work, a mutex must not be released from another context than the one that acquired it. -- Matthias Kaehlcke Linux Application Developer Barcelona Don't walk behind me, I may not lead Don't walk in front of me, I may not follow Just walk beside me and be my friend (Albert Camus) .''`. using free software / Debian GNU/Linux | http://debian.org : :' : `. `'` gpg --keyserver pgp.mit.edu --recv-keys 47D8E5D4 `- - 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/