Re: [PATCH 04/14] memstick: core: fix device_register() errorhandling

From: Greg KH
Date: Wed Sep 22 2010 - 11:50:22 EST


On Wed, Sep 22, 2010 at 12:02:30PM +0200, Boaz Harrosh wrote:
> On 09/22/2010 10:53 AM, Kay Sievers wrote:
> > On Wed, Sep 22, 2010 at 00:49, Greg KH <greg@xxxxxxxxx> wrote:
> >
> >> int device_register(struct device *dev)
> >> {
> >> + int retval;
> >> +
> >> device_initialize(dev);
> >> - return device_add(dev);
> >> + retval = device_add(dev);
> >> + if (retval)
> >> + put_device(dev);
> >> + return retval;
> >> }
> >
> >> Kay, what am I missing here, why can't we just do this? Hm, the
> >> side-affect might be that if device_register() fails, NO ONE had better
> >> touch that device again, as it might have just been freed from the
> >> system. I wonder if that will cause problems...
> >
> > That looks right, besides that there might be callers already doing
> > this. Which needs to be checked.
> >
> > I never liked this pretty useless "convenience API", which just wraps
> > two simple functions and the first one can never fail anyway.
> >
> > We better remove that device_register() stuff entirely in the long
> > run, it's not doing any good. At the kobject level we killed the same
> > stuff already long ago.
> >
>
> That would be fine, and ping me when you do it, I'll help with my
> driver. But don't forget to let us have a way to embed a device inside
> a bigger structure.

That's what you should be doing anyway, so it shouldn't be a problem.

> For meanwhile Please check the patch James sent to add_device that cleans
> up the allocation of the kobj.name member. (And the comment made there)

See my other email why that isn't a good idea.

thanks,

greg k-h
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