From: Theodore Tso Subject: Re: [PATCH 01/10] ext4: Use rcu_barrier() on module unload. Date: Sun, 5 Jul 2009 22:31:13 -0400 Message-ID: <20090706023113.GE6706@mit.edu> References: <20090623150330.22490.87327.stgit@localhost> <20090623150358.22490.24818.stgit@localhost> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: "David S. Miller" , "Paul E. McKenney" , netdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, dougthompson-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org, bluesmoke-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org, axboe-tSWWG44O7X1aa/9Udqfwiw@public.gmane.org, Patrick McHardy , christine.caulfield-gM/Ye1E23mwN+BqQ9rBEUg@public.gmane.org, Trond.Myklebust-HgOvQuBEEgTQT0dZR+AlfA@public.gmane.org, linux-wireless-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, johannes-cdvu00un1VgdHxzADdlk8Q@public.gmane.org, yoshfuji-VfPWfsRibaP+Ru+s062T9g@public.gmane.org, shemminger-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org, linux-nfs-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, bfields-uC3wQj2KruNg9hUCZPvPmw@public.gmane.org, neilb-l3A5Bk7waGM@public.gmane.org, linux-ext4-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, adilger-xsfywfwIY+M@public.gmane.org, netfilter-devel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Jesper Dangaard Brouer Return-path: Content-Disposition: inline In-Reply-To: <20090623150358.22490.24818.stgit@localhost> Sender: linux-nfs-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-ext4.vger.kernel.org On Tue, Jun 23, 2009 at 05:03:59PM +0200, Jesper Dangaard Brouer wrote: > The ext4 module uses rcu_call() thus it should use rcu_barrier()on > module unload. > > The kmem cache ext4_pspace_cachep is sometimes free'ed using > call_rcu() callbacks. Thus, we must wait for completion of call_rcu() > before doing kmem_cache_destroy(). > > I have difficult determining if no new call_rcu() callbacks can be envoked. > Would the maintainer please verify this? Yes, that's correct. Thanks; I've included this in the ext4 patch queue. - Ted -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html