linux-kernel - Re: [PATCH 1/1] acpi: unbreak ACPI_HANDLE(), encapsulate fwnode

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Date:   Tue, 19 Sep 2017 10:44:00 +0300
From:   Mika Westerberg <mika.westerberg@...ux.intel.com>
To:     john.hubbard@...il.com
Cc:     LKML <linux-kernel@...r.kernel.org>, Rob Herring <robh@...nel.org>,
        Sakari Ailus <sakari.ailus@...ux.intel.com>,
        "Rafael J . Wysocki" <rafael.j.wysocki@...el.com>,
        John Hubbard <jhubbard@...dia.com>
Subject: Re: [PATCH 1/1] acpi: unbreak ACPI_HANDLE(), encapsulate
 fwnode_operations

On Fri, Sep 15, 2017 at 05:35:27PM -0700, john.hubbard@...il.com wrote:
> From: John Hubbard <jhubbard@...dia.com>
> 
> Due to commit db3e50f3234b ("device property: Get rid of struct
> fwnode_handle type field"), ACPI_HANDLE() inadvertently became
> a GPL-only call. The call path that led to that was:
> 
> ACPI_HANDLE()
>     ACPI_COMPANION()
>         to_acpi_device_node()
>             is_acpi_device_node()
>                 acpi_device_fwnode_ops
>                     DECLARE_ACPI_FWNODE_OPS(acpi_device_fwnode_ops);
> 
> ...and the new DECLARE_ACPI_FWNODE_OPS() includes
> EXPORT_SYMBOL_GPL, whereas previously it was a static struct.
> 
> In order to avoid changing any of that, let's instead provide ever
> so slightly better encapsulation of those struct fwnode_operations
> instances. Those do not really need to be directly used in
> inline function calls in header files. Simply moving two small
> functions (is_acpi_device_node and is_acpi_data_node) out of
> acpi_bus.h, and into a .c file, does that.
> 
> That leaves the internals of struct fwnode_operations as GPL-only
> (which I think was the intent all along), but un-breaks any driver
> code out there that relies on the ACPI subsystem's being (historically)
> an EXPORT_SYMBOL-usable system. By that, I mean, ACPI_HANDLE() and
> other basic ACPI calls were non-GPL-protected.
> 
> Also, while I'm there, remove a tiny bit of redundancy that was missed
> in the earlier commit, by having is_acpi_node() use the other two
> routines, instead of checking fwnode directly.
> 
> Signed-off-by: John Hubbard <jhubbard@...dia.com>

Acked-by: Mika Westerberg <mika.westerberg@...ux.intel.com>