Date: Wed, 2 Sep 2009 17:05:06 -0700
From: Greg KH <greg@kroah.com>
To: Tejun Heo <tj@kernel.org>
Cc: Grant Grundler <grundler@parisc-linux.org>,
       Linux Kernel <linux-kernel@vger.kernel.org>, linux-pci@vger.kernel.org,
       Shane Huang <Shane.Huang@amd.com>
Subject: Re: [PATCH] pci: separate out pci_add_dynid()
Message-ID: <20090903000506.GA31897@kroah.com>
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 <4A9EF402.7090800@kernel.org>
 <4A9EF510.9080902@kernel.org>
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On Thu, Sep 03, 2009 at 07:43:28AM +0900, Tejun Heo wrote:
> Ummm... another thought.
> 
> Tejun Heo wrote:
> > It's one of the gripes I've had with the driver core interface.
> > Returning the object which had its reference bumped up is nice to do
> > do_something(get_driver(driver)); but it should have been made clear
> > that the return value always equals the input parameter.  IIRC, in the
> > early days of the current driver model and kref, there were intentions
> > to make kref somehow more capable and handle the last reference
> > problem from within it so that if (get_driver(driver)) test is
> > actually meaningful but that turned out to be not too feasible, so we
> > ended up with unnecessary if () around driver model get functions.  I
> > try to remove them whenever an affected piece of code is being
> > modified but there still are plenty left.  I'll update comment on
> > driver core get functions.
> 
> Greg, I think I suggested this before.  What do you think about just
> making those get functions return void?

I have no objection to that at all.

> The current interface combined with widespread if() around them is
> quite misleading.

I agree.

> Most device/driver structures are inherited and extended when actually
> in use, so the driver or its subsystem code usually can't do much with
> the return value other than checking for bogus error condition anyway.

I totally agree.

thanks,

greg k-h
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