From mboxrd@z Thu Jan 1 00:00:00 1970 From: Valerie Aurora Subject: Re: [PATCH] VFS: Sanity check mount flags passed to change_mnt_propagation() Date: Fri, 27 Aug 2010 14:12:05 -0400 Message-ID: <20100827181205.GD26872@shell> References: <20100826200318.GA13636@shell> <20100827011436.GB3521@parisc-linux.org> <20100827174313.GA26872@shell> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Matthew Wilcox , Alexander Viro , Karel Zak , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org To: Bob Copeland Return-path: Received: from mx1.redhat.com ([209.132.183.28]:28717 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751392Ab0H0SMd (ORCPT ); Fri, 27 Aug 2010 14:12:33 -0400 Content-Disposition: inline In-Reply-To: Sender: linux-fsdevel-owner@vger.kernel.org List-ID: On Fri, Aug 27, 2010 at 01:51:06PM -0400, Bob Copeland wrote: > On Fri, Aug 27, 2010 at 1:43 PM, Valerie Aurora wrote: > > On Thu, Aug 26, 2010 at 07:14:36PM -0600, Matthew Wilcox wrote: > >> Hrm. ?I think we can do this a bit more pithily. > >> > >> ? ? ? /* Only one propagation flag should be set, and no others */ > >> ? ? ? if (hweight32(type) != 1 && > >> ? ? ? ? ? (type & ~(MS_SHARED | MS_PRIVATE | MS_SLAVE | MS_UNBINDABLE)) > >> ? ? ? ? ? ? ? return 0; > >> > >> Too clever? > > > > I was hoping someone would go find the best bitop for me, thanks. :) > > hweight32() is an awkward name but the comment makes it clear. ?I'm > > happy with either. > > > > Thanks for the help, > > Didn't read surrounding code, but is that supposed to be '||'? > > Otherwise the case where only a single non-propagation flag is > set no longer returns 0... Yes, thanks! I'll run the test program again before resubmitting. :) -VAL