From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755250Ab1H2Xz3 (ORCPT ); Mon, 29 Aug 2011 19:55:29 -0400 Received: from waldorf.bytemark.co.uk ([212.110.162.22]:44483 "EHLO waldorf.bytemark.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753838Ab1H2Xz2 (ORCPT ); Mon, 29 Aug 2011 19:55:28 -0400 Date: Mon, 29 Aug 2011 19:55:08 -0400 From: "Emilio G. Cota" To: Greg KH , Manohar Vanga Cc: gregkh@suse.de, martyn.welch@ge.com, devel@driverdev.osuosl.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 2/3] staging: vme: add struct vme_dev for VME devices Message-ID: <20110829235508.GA30400@flamenco.cs.columbia.edu> References: <1314608570-32766-1-git-send-email-manohar.vanga@cern.ch> <1314608570-32766-3-git-send-email-manohar.vanga@cern.ch> <20110829175241.GC10250@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20110829175241.GC10250@kroah.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Aug 29, 2011 at 10:52:41 -0700, Greg KH wrote: > On Mon, Aug 29, 2011 at 11:02:49AM +0200, Manohar Vanga wrote: > > --- a/drivers/staging/vme/vme_bridge.h > > +++ b/drivers/staging/vme/vme_bridge.h > > @@ -115,9 +115,8 @@ struct vme_bridge { > > struct list_head bus_list; /* list of VME buses */ > > struct module *owner; /* module that owns the bridge */ > > > > - struct device dev[VME_SLOTS_MAX]; /* Device registered with > > - * device model on VME bus > > - */ > > + struct vme_dev dev[VME_SLOTS_MAX]; /* Device registered > > + * on VME bus */ > > Overall, this is the right way to go, using a vme_dev. > > BUT, you should never have a static list of devices, these should be > pointers, not actual structures here, otherwise your reference counting > just got all messed up and is wrong. > > And yes, I know you didn't create the code this way, but it needs to be > fixed _before_ you make this kind of a change. True, I overlooked this while reviewing >_< Manohar, have a look at vme_unregister_driver_ng() and __vme_register_driver_bus() in this patch: http://article.gmane.org/gmane.linux.kernel/1054046 Note that there's no kfree(vme_dev) in those functions. put_device(), which is also called from device_unregister(), decrements the underlying kobj's refcount. When this refcount reaches 0, kobject_release() is called. Eventually dev->release() gets called, which in this case is set to vme_dev_release_ng(); it's there (and only there) where vme_dev can be freed. Emilio