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From: "Luis R. Rodriguez" <lrodriguez@atheros.com>
Date: Sun, 20 Sep 2009 07:43:17 -0700
Message-ID: <43e72e890909200743h74934657nc056c9e6dcb14e90@mail.gmail.com>
Subject: Re: [RFC] compat-2.6: mangle symbols for driver-select
To: tim.gardner@canonical.com
Cc: linux-wireless@vger.kernel.org, Greg KH <greg@kroah.com>,
	Johannes Berg <johannes@sipsolutions.net>
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Sender: linux-wireless-owner@vger.kernel.org

On Sat, Sep 19, 2009 at 8:46 PM, Tim Gardner <tim.gardner@canonical.com> wrote:
> Luis R. Rodriguez wrote:
>>
>> Today at the summit we spoke about mangling symbols for driver-slect.
>> Here's a quick nasty take on this but without doing this for driver-select
>> specifically just for testing. It seems to compile, but someone more
>> motivated
>> may want to test and make this apply somehow only for driver-select or
>> perhaps
>> when a -D define is used.
>>
>> Reason for this is to help distributions / OEMs / ODMs who want to replace
>> just *one* driver with compat-wireless.
>>
>
> I think it would be better to generate the list of mangled symbols
> dynamically.

Agreed, that is the part I left out, as a TODO to someone interested.

> In older Ubuntu releases (before depmod behavior was
> corrected), we have to run a 'munge' script to preface all of the exported
> symbols so that a compat-wireless driver references the compat-wireless
> protocol stack symbols. See the attached munge script for compat-wireless on
> 2.6.24.

Please correct me if I'm wrong but I believe the script seems to do
what I did just that it actually edited the files with the changes, I
prefer the way I did this as it requires less work to maintain and
understand IMHO.

> We can either do something like this for compat-wireless, or we
> could use a subset of this logic to generate the list of symbols contained
> within the '#ifdef CONFIG_COMPAT_WIRELESS_MANGLE' clause.

So I was under the impression you would use this only if you are using
./scripts/driver-select to select one driver out of the whole tree,
but it seems you actually use this for all the drivers on
compat-wireless for the Ubuntu linux-backports-modules package. I take
it you put lbm stuff then into some /lib/modules/$(uname)/compat/ and
use a sort of /etc/depmod.d/01-compat.conf to prefer compat over
updates/ or kernel/ ?

  Luis