linux-kernel - Re: [PATCH -v3 5/8] fsnotify: unified filesystem notification backend

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <1227914568.3393.5.camel@localhost.localdomain>
Date:	Fri, 28 Nov 2008 18:22:48 -0500
From:	Eric Paris <eparis@...hat.com>
To:	Peter Zijlstra <a.p.zijlstra@...llo.nl>
Cc:	linux-kernel@...r.kernel.org, malware-list@...ts.printk.net,
	viro@...iv.linux.org.uk, akpm@...ux-foundation.org,
	alan@...rguk.ukuu.org.uk, arjan@...radead.org, hch@...radead.org
Subject: Re: [PATCH -v3 5/8] fsnotify: unified filesystem notification
 backend

On Thu, 2008-11-27 at 17:20 +0100, Peter Zijlstra wrote:
> On Tue, 2008-11-25 at 12:21 -0500, Eric Paris wrote:
> > +int fsnotify_check_notif_queue(struct fsnotify_group *group)
> > +{
> > +       mutex_lock(&group->notification_mutex);
> > +       if (!list_empty(&group->notification_list))
> > +               return 1;
> > +       mutex_unlock(&group->notification_mutex);
> > +       return 0;
> > +}
> 
> > +void fsnotify_clear_notif(struct fsnotify_group *group)
> > +{
> > +       struct fsnotify_event *event;
> > +
> > +       while (fsnotify_check_notif_queue(group)) {
> > +               event = get_event_from_notif(group);
> > +               fsnotify_put_event(event);
> > +               /* fsnotify_check_notif_queue() took this lock */
> > +               mutex_unlock(&group->notification_mutex);
> > +       }
> > +}
> 
> That is quite horrible, please just open code that to keep the locking
> symmetric.

While horrible, I use fsnotify_check_notif_queue in my fsnotify (not in
this series as this only includes dnotify) has

wait_event_interruptible(group->notification_waitq, fanotify_check_notif_queue(group));

So I wouldn't know how to open code that...  I can open code this
instance, but it's going to mean redoing all of that other code to
handle having thing not be present when we return.  Since I didn't
submit that as well I guess I'm not allowed to use it as a reason...

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/