Subject: Re: [RFC] New kobject/kset/ktype documentation and example code
From: Kay Sievers <kay.sievers@vrfy.org>
To: Alan Stern <stern@rowland.harvard.edu>
Cc: Greg KH <greg@kroah.com>,
       Kernel development list <linux-kernel@vger.kernel.org>,
       Jonathan Corbet <corbet@lwn.net>,
       Randy Dunlap <randy.dunlap@oracle.com>,
       Cornelia Huck <cornelia.huck@de.ibm.com>
In-Reply-To: <Pine.LNX.4.44L0.0711281432290.5566-100000@iolanthe.rowland.org>
References: <Pine.LNX.4.44L0.0711281432290.5566-100000@iolanthe.rowland.org>
Content-Type: text/plain
Date: Wed, 28 Nov 2007 20:46:12 +0100
Message-Id: <1196279172.3242.119.camel@lov.site>
Mime-Version: 1.0
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 1518
Lines: 36

On Wed, 2007-11-28 at 14:36 -0500, Alan Stern wrote:
> On Wed, 28 Nov 2007, Kay Sievers wrote:
> 
> > > Actually the current code doesn't seem to check whether kobj->ktype is
> > > NULL or to use the value of kobj->kset->kobj.ktype.  Is this an oversight?
> > 
> > We just require the ktype.
> 
> No -- we should but we don't.  Look at the code for kobject_init() and
> kobject_add() in Greg's tree and you'll see.  Neither of them checks
> that kobj->ktype is set.

Yeah, it was another "magic" that was built into the core, the code even
tried to find sysfs_ops for completely untyped kobjects. That is gone
now, and we should just require a ktype, I think.

> > > If there is no containing kset, the parent remains NULL.  What happens
> > > then?  Does the kobject show up in the sysfs top-level directory?
> > 
> > "If the kobject belonging to a kset has no parent kobject set, it will
> > be added to the kset's directory. Not all members of a kset do
> > necessarily live in the kset directory. If an explicit parent kobject is
> > assigned before the kobject is added, the kobject is registered with the
> > kset, but added below the parent kobject."
> 
> Yes, but what if neither kobj->parent nor kobj->kset is set?

It will show up in the root of sysfs, yes.

Kay

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/