From: Jesper Dangaard Brouer Subject: Re: [PATCH 07/10] decnet: Use rcu_barrier() on module unload. Date: Sat, 27 Jun 2009 09:35:04 +0200 Message-ID: <1246088104.29340.5.camel@localhost.localdomain> References: <1245845367.24921.3.camel@localhost.localdomain> <5A680E0A-EFEB-44EA-9F06-F338E6CBD6D1@googlemail.com> <1245930729.24921.67.camel@localhost.localdomain> <20090625.161046.19938291.davem@davemloft.net> Mime-Version: 1.0 Content-Type: text/plain Cc: Jesper Dangaard Brouer , David Miller , paulmck@linux.vnet.ibm.com, netdev , LKML , Patrick McHardy , yoshfuji@linux-ipv6.org, linux-nfs@vger.kernel.org, linux-ext4@vger.kernel.org, catalin.marinas@gmail.com To: Christian Kujau Return-path: In-Reply-To: Sender: linux-ext4-owner@vger.kernel.org List-ID: On Fri, 2009-06-26 at 20:15 -0700, Christian Kujau wrote: > On Fri, 26 Jun 2009, Jesper Dangaard Brouer wrote: > > I'll resubmit the patches to you and netdev, to limit the spam effect... > > Out of curiosity: why was linux-ext4 Cc'ed on these rcu_barrier patches > (but not other fs-lists but linux-nfs)? I did not see any ../fs/ext4/ > changes. There was a ../fs/ext4/ change in patch [01/10]. Titled: "ext4: Use rcu_barrier() on module unload" git show --stat d6a4ea73b7e8779607dd48735d9a9c521c890857 commit d6a4ea73b7e8779607dd48735d9a9c521c890857 Author: Jesper Dangaard Brouer Date: Tue Jun 23 15:40:54 2009 +0200 ext4: Use rcu_barrier() on module unload. 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? Signed-off-by: Jesper Dangaard Brouer fs/ext4/mballoc.c | 4 +++- 1 files changed, 3 insertions(+), 1 deletions(-) -- Med venlig hilsen / Best regards Jesper Brouer ComX Networks A/S Linux Network developer Cand. Scient Datalog / MSc. Author of http://adsl-optimizer.dk LinkedIn: http://www.linkedin.com/in/brouer