linux-kernel - Re: [PATCH] kobject: make sure kobj->ktype is set before kobject

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Date:	Thu, 29 Nov 2007 20:51:23 +0100
From:	Kay Sievers <kay.sievers@...y.org>
To:	Alan Stern <stern@...land.harvard.edu>
Cc:	Cornelia Huck <cornelia.huck@...ibm.com>, Greg KH <greg@...ah.com>,
	Kernel development list <linux-kernel@...r.kernel.org>,
	Jonathan Corbet <corbet@....net>,
	Randy Dunlap <randy.dunlap@...cle.com>
Subject: Re: [PATCH] kobject: make sure kobj->ktype is set before
	kobject_init

On Thu, 2007-11-29 at 14:05 -0500, Alan Stern wrote:
> On Thu, 29 Nov 2007, Kay Sievers wrote:
> 
> > Your error scenario confirmed my initial concern about suggesting
> > kobject_put() to clean up an initialized kobject.
> > 
> > We should probably make kobject_cleanup() free only the resources taken
> > by kobject_init(), and use kobject_cleanup() instead of kobject_put()?
> 
> My conclusion is different.  We should make kobject_init() not consume
> any resources at all; just initialize various fields.  That way it
> would be okay to call either kfree() or kobject_put() on an initialized
> kobject.  And then when something like device_register() fails, the
> caller would know the proper thing to do would be to call the put()  
> routine, always.
> 
> Of course, once the name has been assigned, only kobject_put() should
> be used.

Now we just move the exactly the same problem from _init() to
_set_name(). To free the name of an unregistered we would need to call
_put() which free()'s the whole object again. :) 

> There's another good reason for not assigning the name in
> kobject_init(): Code that uses kobjects (like the driver core) doesn't
> set the name until later.

That can be done at any stage, I guess. We will rip out the name in the
struct device anyway.

Kay

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