if cdev_add() fails, do you need to "put" the cdev's kobject?

[Robert P. J. Day]

On Tue, 3 May 2011, Greg KH wrote:

> On Tue, May 03, 2011 at 05:46:05PM -0400, Robert P. J. Day wrote:
> >
> >   still perusing various drivers to use as examples in class, and i
> > ran across this snippet in the load routine of drivers/char/raw.c:
> >
> > ===== start excerpt =====
> >
> >         cdev_init(&raw_cdev, &raw_fops);
> >         ret = cdev_add(&raw_cdev, dev, MAX_RAW_MINORS);
> >         if (ret) {
> >                 kobject_put(&raw_cdev.kobj);
> >                 goto error_region;
> >         }
> >
> > ===== end =====
> >
> >   of course it's wise to check the return code from cdev_add() to make
> > sure it worked, but is it really necessary to call kobject_put()
> > there?
>
> No, that is wrong.  No one should ever mess with the kobject in a cdev.
> I want to call it something other than a kobject, as it's not really
> used as you would think of a kobject (it's used in the hash lookup of
> the object when userspace opens a chardev, it has nothing to do with
> sysfs.)

  so based on the code surrounding that snippet, a quick fix for now
would be to simply remove that call to kobject_put(), correct?  there
might be other cleanup but, for now, that removal would seem to be
obvious.  if so, i can submit a patch.

rday

-- 

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Robert P. J. Day                                 Ottawa, Ontario, CANADA
                        http://crashcourse.ca

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