Re: [PATCH 5/5] checkpatch: fix false EXPORT_SYMBOL warning

[Andy Whitcroft <apw@canonical.com>]

On Mon, Sep 21, 2009 at 07:14:51PM -0700, Daniel Walker wrote:
> Ingo reported that the following lines triggered a false warning,
> 
> static struct lock_class_key rcu_lock_key;
> struct lockdep_map rcu_lock_map =
>         STATIC_LOCKDEP_MAP_INIT("rcu_read_lock", &rcu_lock_key);
> EXPORT_SYMBOL_GPL(rcu_lock_map);
> 
> from kernel/rcutree.c , and the false warning looked like this,
> 
> WARNING: EXPORT_SYMBOL(foo); should immediately follow its
> function/variable
> +EXPORT_SYMBOL_GPL(rcu_lock_map);
> 
> This change corrects this. It was caused because checkpatch doesn't check
> more than one line above the "EXPORT_SYMBOL" for additional context (ie.
> variable name, or initializer). Things are somewhat more complicated
> because STATIC_LOCKDEP_MAP_INIT() doesn't accept the variable name that
> is being initialized. I just added another check that checks two lines
> above "EXPORT_SYMBOL" for the variable declaration.

In theory the thing we are exporting can be an arbitrary number of lines
prior to the EXPORT_SYMBOL statement.  We actually want to look at the
statement before the EXPORT_*. 

I had a go at doing it this way and it seems to work on my test sets.
Perhaps you could test the version at the url below:

  http://www.kernel.org/pub/linux/kernel/people/apw/checkpatch/checkpatch.pl-testing

NOTE: you want at least version 0.29-5-* which is in the process of 
mirroring out.

-apw