Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755095Ab0H0RvJ (ORCPT ); Fri, 27 Aug 2010 13:51:09 -0400 Received: from mail-vw0-f46.google.com ([209.85.212.46]:36273 "EHLO mail-vw0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751276Ab0H0RvI convert rfc822-to-8bit (ORCPT ); Fri, 27 Aug 2010 13:51:08 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:sender:in-reply-to:references:date :x-google-sender-auth:message-id:subject:from:to:cc:content-type :content-transfer-encoding; b=mebIqRECY/aJv1rTrM/CcXScvqGdugs+QrIjrnm6xWKxUd9Fv8LxXBM0pOk4xUVwXk C1ENgcdnvdKy7JvV6GvoiNfMHZhbyUyo2j08cpiRxXp8kYDCA+t2ZmXkGoq/+TzR3/VC /SciJy4ICIyYadJfhjncyGzNKL2CSJDb5e7VU= MIME-Version: 1.0 In-Reply-To: <20100827174313.GA26872@shell> References: <20100826200318.GA13636@shell> <20100827011436.GB3521@parisc-linux.org> <20100827174313.GA26872@shell> Date: Fri, 27 Aug 2010 13:51:06 -0400 X-Google-Sender-Auth: mvItC_kvfJBAn93aTuEmkImTmZQ Message-ID: Subject: Re: [PATCH] VFS: Sanity check mount flags passed to change_mnt_propagation() From: Bob Copeland To: Valerie Aurora Cc: Matthew Wilcox , Alexander Viro , Karel Zak , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1054 Lines: 29 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... -- Bob Copeland %% www.bobcopeland.com -- 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/