From mboxrd@z Thu Jan  1 00:00:00 1970
From: jamie@jamieiles.com (Jamie Iles)
Date: Tue, 18 Oct 2011 15:56:49 +0100
Subject: [PATCH 2/6] drivers/base: add bus for System-on-Chip devices
In-Reply-To: <201110181653.09425.arnd@arndb.de>
References: <1318852378-14180-1-git-send-email-lee.jones@linaro.org>
	<201110181605.12512.arnd@arndb.de> <20111018141520.GA10054@totoro>
	<201110181653.09425.arnd@arndb.de>
Message-ID: <20111018145649.GB10054@totoro>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

On Tue, Oct 18, 2011 at 04:53:09PM +0200, Arnd Bergmann wrote:
> On Tuesday 18 October 2011, Jamie Iles wrote:
> > Also, (and I'm right at the edge of my knowledge here!) wouldn't you 
> > also need to add reference counting of the module when 
> > creating/destroying a soc device to prevent the module and bus 
> > disappearing whilst you had devices with a reference to it?
> 
> No, that's not necessary in a case like this: The bus module remains
> pinned by the reference of the module calling it on each exported
> symbol that is referenced. The reference counting is only needed
> if driver module provides function pointers to the bus module
> that might be in the middle of getting called while the driver is
> removed. We have this case with the ux500_get_process function
> that may be called through sysfs, so that would be a bug if the
> code calling device_create_file() was in a module.

Ahh, okay that makes sense.  Thanks for the explanation Arnd.

Jamie