Subject: Re: [PATCH][v2] powerpc: move epapr paravirt init of power_save to an initcall

From: Alexander Graf <[email-masked]>
Date: Wed, 30 Apr 2014 22:25:19 +0200

On 30.04.14 22:20, Stuart Yoder wrote:
> From: Stuart Yoder <[email-masked]>
>
> some restructuring of epapr paravirt init resulted in
> ppc_md.power_save being set, and then overwritten to
> NULL during machine_init.  This patch splits the
> initialization of ppc_md.power_save out into a postcore
> init call.
>
> Signed-off-by: Stuart Yoder <[email-masked]>

Looks pretty good to me and IMHO should get a CC on stable when it gets 
into the tree. One minor nit below.

We still need to clarify whether the omitted check on 
early_init_dt_scan_epapr() is on purpose and if not reintroduce it, but 
that's a separate issue.

> ---
>
> -v2: don't iterate over the entire DT, just look at
>   the hypervisor node
>
>   arch/powerpc/kernel/epapr_paravirt.c |   25 ++++++++++++++++++++-----
>   1 file changed, 20 insertions(+), 5 deletions(-)
>
> diff --git a/arch/powerpc/kernel/epapr_paravirt.c b/arch/powerpc/kernel/epapr_paravirt.c
> index 7898be9..a01df5e 100644
> --- a/arch/powerpc/kernel/epapr_paravirt.c
> +++ b/arch/powerpc/kernel/epapr_paravirt.c
> @@ -53,11 +53,6 @@ static int __init early_init_dt_scan_epapr(unsigned long node,
>   #endif
>   	}
>   
> -#if !defined(CONFIG_64BIT) || defined(CONFIG_PPC_BOOK3E_64)
> -	if (of_get_flat_dt_prop(node, "has-idle", NULL))
> -		ppc_md.power_save = epapr_ev_idle;
> -#endif
> -
>   	epapr_paravirt_enabled = true;
>   
>   	return 1;
> @@ -70,3 +65,23 @@ int __init epapr_paravirt_early_init(void)
>   	return 0;
>   }
>   

v

> +static int __init epapr_idle_init(void)
> +{
> +	struct device_node *node;
> +
> +	if (!epapr_paravirt_enabled)
> +		return 0;
> +
> +	node = of_find_node_by_path("/hypervisor");
> +	if (!node)
> +		return -ENODEV;
> +
> +#if !defined(CONFIG_64BIT) || defined(CONFIG_PPC_BOOK3E_64)

Please move the #if scope from v to ^. That way we don't waste space / 
time / anything on systems that don't bother with the idle hcall.

> +	if (of_get_property(node, "has-idle", NULL))
> +		ppc_md.power_save = epapr_ev_idle;
> +#endif
> +
> +	return 0;
> +}
> +
> +postcore_initcall(epapr_idle_init);

^

Alex