From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754132Ab0KBAqa (ORCPT ); Mon, 1 Nov 2010 20:46:30 -0400 Received: from bld-mail18.adl2.internode.on.net ([150.101.137.103]:35945 "EHLO mail.internode.on.net" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753523Ab0KBAq1 (ORCPT ); Mon, 1 Nov 2010 20:46:27 -0400 Date: Tue, 2 Nov 2010 11:45:45 +1100 From: Dave Chinner To: Mimi Zohar Cc: linux-kernel@vger.kernel.org, linux-security-module@vger.kernel.org, linux-fsdevel@vger.kernel.org, jmorris@namei.org, akpm@linux-foundation.org, torvalds@linux-foundation.org, eparis@redhat.com, viro@zeniv.linux.org.uk, Mimi Zohar Subject: Re: [PATCH v1.1 2/5] IMA: define readcount functions Message-ID: <20101102004545.GQ2715@dastard> References: <1288640739-3246-1-git-send-email-zohar@linux.vnet.ibm.com> <1288640739-3246-3-git-send-email-zohar@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1288640739-3246-3-git-send-email-zohar@linux.vnet.ibm.com> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Nov 01, 2010 at 03:45:36PM -0400, Mimi Zohar wrote: > Define iget/iput_readcount() functions to be called from the VFS layer. Can't say I like the function names. i_readcount_{inc,dec} seem more appropriate, especially so they don't get confused with inode reference counting... Cheers, Dave. > +void iput_readcount(struct inode *inode) > +{ > + spin_lock(&inode->i_lock); > + if (unlikely((atomic_read(&inode->i_readcount) == 0))) > + printk(KERN_INFO "i_readcount: imbalance ino %ld\n", > + inode->i_ino); > + else > + atomic_dec(&inode->i_readcount); > + spin_unlock(&inode->i_lock); > +} No need for the lock just to indicate an imbalance. You could just use: if (atomic_dec_return(&inode->i_readcount) < 0) { ..... } Given this is an integrity subsystem, I suspect the correct thing to do here is BUG(), not just issue an informational message that something is wrong with the integrity tracking.... Cheers, Dave. -- Dave Chinner david@fromorbit.com