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Subject: Re: [PATCH] powerpc: Export __spin_yield
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: "Suresh E. Warrier" <warrier@linux.vnet.ibm.com>
Date: Tue, 24 Feb 2015 14:38:39 +1100
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On Mon, 2015-02-23 at 18:10 -0600, Suresh E. Warrier wrote:
> Export __spin_yield so that the arch_spin_unlock() function
> can be invoked from a module.

Make it EXPORT_SYMBOL_GPL. Also explain why a module might need it

> Signed-off-by: Suresh Warrier <warrier@linux.vnet.ibm.com>
> ---
>  arch/powerpc/lib/locks.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/arch/powerpc/lib/locks.c b/arch/powerpc/lib/locks.c
> index bb7cfec..d100de8 100644
> --- a/arch/powerpc/lib/locks.c
> +++ b/arch/powerpc/lib/locks.c
> @@ -41,6 +41,7 @@ void __spin_yield(arch_spinlock_t *lock)
>  	plpar_hcall_norets(H_CONFER,
>  		get_hard_smp_processor_id(holder_cpu), yield_count);
>  }
> +EXPORT_SYMBOL(__spin_yield);
> 
>  /*
>   * Waiting for a read lock or a write lock on a rwlock...