Re: [PATCH] bus: subsys: propagate errors from subsys interface's ->add_dev()

[Greg KH <gregkh@linuxfoundation.org>]

On Fri, Jun 26, 2015 at 02:32:47PM +0530, Viresh Kumar wrote:
> ->add_dev() may fail and the error returned from it can be useful for
> the caller.
> 
> For example, if some of the resources aren't ready yet and -EPROBE_DEFER
> is returned from ->add_dev(), then the owner of 'struct
> subsys_interface' may want to try probing again at a later point of
> time. And that requires a proper return value from ->add_dev().
> 
> Also, if we hit an error while registering subsys_interface, then we
> should stop proceeding further and rollback whatever has been done until
> then. Break part of subsys_interface_unregister() into another routine,
> which lets us call ->remove_dev() for all devices for which ->add_dev()
> is already called.
> 
> Cc: 3.3+ <stable@vger.kernel.org> # 3.3+
> Fixes: ca22e56debc5 ("driver-core: implement 'sysdev' functionality for regular devices and buses")

I don't see how this is a stable bug fix, what is resolved by it that
doesn't work today?  Is there some code that is expecting this
functionality that has never been present?

I'll go queue it up, but I don't think it is -stable material, but feel
free to change my mind.

greg k-h