From: Trond Myklebust Subject: Re: [PATCH 5/5] sunrpc/auth_gss: Call rcu_barrier() on module unload. Date: Mon, 08 Jun 2009 13:00:49 -0400 Message-ID: <1244480449.5040.4.camel@heimdal.trondhjem.org> References: <20090608130959.10052.54590.stgit@localhost> <20090608131148.10052.39869.stgit@localhost> <20090608162656.GF6961@linux.vnet.ibm.com> Mime-Version: 1.0 Content-Type: text/plain Cc: Jesper Dangaard Brouer , "David S. Miller" , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, urs.thuermann-l29pVbxQd1IUtdQbppsyvg@public.gmane.org, oliver.hartkopp-l29pVbxQd1IUtdQbppsyvg@public.gmane.org, wg-5Yr1BZd7O62+XT7JhA+gdA@public.gmane.org, vladislav.yasevich@hp.com, sri@us.ibm.com, linux-sctp@vger.kernel.org, linux-nfs@vger.kernel.org, netfilter-devel@vger.kernel.org To: paulmck@linux.vnet.ibm.com Return-path: Received: from mx2.netapp.com ([216.240.18.37]:11181 "EHLO mx2.netapp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755960AbZFHRBQ (ORCPT ); Mon, 8 Jun 2009 13:01:16 -0400 In-Reply-To: <20090608162656.GF6961@linux.vnet.ibm.com> Sender: linux-nfs-owner@vger.kernel.org List-ID: On Mon, 2009-06-08 at 09:26 -0700, Paul E. McKenney wrote: > On Mon, Jun 08, 2009 at 03:11:48PM +0200, Jesper Dangaard Brouer wrote: > > As the module uses rcu_call() we should make sure that all > > rcu callback has been completed before removing the code. > > Good improvement!!! Assuming that gss_svc_shutdown() and > rpcauth_unregister() prevent any future RCU callbacks to be registered, > this patch will fix things up. > > Acked-by: Paul E. McKenney > > > Signed-off-by: Jesper Dangaard Brouer > > --- > > > > net/sunrpc/auth_gss/auth_gss.c | 1 + > > 1 files changed, 1 insertions(+), 0 deletions(-) > > > > diff --git a/net/sunrpc/auth_gss/auth_gss.c b/net/sunrpc/auth_gss/auth_gss.c > > index e630b38..66d458f 100644 > > --- a/net/sunrpc/auth_gss/auth_gss.c > > +++ b/net/sunrpc/auth_gss/auth_gss.c > > @@ -1548,6 +1548,7 @@ static void __exit exit_rpcsec_gss(void) > > { > > gss_svc_shutdown(); > > rpcauth_unregister(&authgss_ops); > > + rcu_barrier(); /* Wait for completion of call_rcu()'s */ > > } > > > > MODULE_LICENSE("GPL"); > > Hmm... If this is about ensuring that all the call_rcu() callbacks complete before we remove the module, then don't we also need similar barriers in net/sunrpc/sunrpc_syms.c:cleanup_sunrpc() and in fs/nfs/inode.c:exit_nfs_fs()? Cheers Trond -- Trond Myklebust Linux NFS client maintainer NetApp Trond.Myklebust@netapp.com www.netapp.com