From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Nicholas A. Bellinger" Subject: Re: [RFC 22/22] tcm_loop: Add multi-fabric Linux/SCSI LLD fabric module Date: Sun, 05 Sep 2010 23:01:01 -0700 Message-ID: <1283752861.556.200.camel@haakon2.linux-iscsi.org> References: <1283160203-6981-1-git-send-email-nab@linux-iscsi.org> <20100905203006.GD18411@core.coreip.homeip.net> <1283723479.556.135.camel@haakon2.linux-iscsi.org> <20100906050816.GD17212@core.coreip.homeip.net> <20100906051703.GA2891@suse.de> <1283750480.556.196.camel@haakon2.linux-iscsi.org> <20100906053845.GG17212@core.coreip.homeip.net> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Return-path: Received: from smtp104.sbc.mail.ne1.yahoo.com ([98.138.84.215]:32409 "HELO smtp104.sbc.mail.ne1.yahoo.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1752439Ab0IFGFC (ORCPT ); Mon, 6 Sep 2010 02:05:02 -0400 In-Reply-To: <20100906053845.GG17212@core.coreip.homeip.net> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: Dmitry Torokhov Cc: Greg KH , linux-scsi , linux-kernel , FUJITA Tomonori , Mike Christie , Christoph Hellwig , Hannes Reinecke , James Bottomley , Jens Axboe , Boaz Harrosh On Sun, 2010-09-05 at 22:38 -0700, Dmitry Torokhov wrote: > On Sun, Sep 05, 2010 at 10:21:20PM -0700, Nicholas A. Bellinger wrote: > > On Sun, 2010-09-05 at 22:17 -0700, Greg KH wrote: > > > On Sun, Sep 05, 2010 at 10:08:16PM -0700, Dmitry Torokhov wrote: > > > > On Sun, Sep 05, 2010 at 02:51:19PM -0700, Nicholas A. Bellinger wrote: > > > > > On Sun, 2010-09-05 at 13:30 -0700, Dmitry Torokhov wrote: > > > > > > On Mon, Aug 30, 2010 at 02:23:23AM -0700, Nicholas A. Bellinger wrote: > > > > > > > + > > > > > > > +static void tcm_loop_primary_release(struct device *dev) > > > > > > > +{ > > > > > > > + return; > > > > > > > +} > > > > > > > + > > > > > > > +static struct device tcm_loop_primary = { > > > > > > > + .init_name = "tcm_loop_0", > > > > > > > + .release = tcm_loop_primary_release, > > > > > > > +}; > > > > > > > + > > > > > > > > > > > > No, you can not have statically allocated devices and dummy release > > > > > > functions. > > > > > > > > > > > > > > > > Last time I checked this is still what mainline > > > > > drivers/scsi/scsi_debug.c is doing for struct device pseudo_primary: > > > > > > > > > > static void pseudo_0_release(struct device *dev) > > > > > { > > > > > if (SCSI_DEBUG_OPT_NOISE & scsi_debug_opts) > > > > > printk(KERN_INFO "scsi_debug: pseudo_0_release() called\n"); > > > > > } > > > > > > > > > > static struct device pseudo_primary = { > > > > > .init_name = "pseudo_0", > > > > > .release = pseudo_0_release, > > > > > }; > > > > > > > > > > so for these type of things in TCM_Loop I tend to follow what scsi_debug does, > > > > > so I don't exactly see a issue here atm. Anybody else have comments..? > > > > > > > > The kobject embedded in the device structure is refcounted and it's > > > > lifetime may be different from lifetime of your module. If somebody > > > > happen to hold reference to the driver while your module is being > > > > unloaded bad things will happen. > > > > > > > > I am sure Greg has something on this topic ready for cut-and-paste. > > > > > > Documentation/kobject.txt :) > > > > I still don't get it..? Does this mean that scsi_debug and TCM_Loop are > > currently broken wrt to this item or not..? > > > > Yes they are broken. Hi Dmitry and Greg, Would you mind giving a bit more specific idea as to what a patch to fix this issue would involve for an emulated struct device usage..? I would be happy to generate patches for scsi_debug and TCM_loop to resolve this issue, but I need a bit more information what I should be looking at. Thanks, --nab