Re: [PATCH] powerpc: use device_online/offline() instead of cpu_up/down()

[Nathan Fontenot <nfont@linux.vnet.ibm.com>]

On 10/31/2014 02:41 PM, Dan Streetman wrote:
> In powerpc pseries platform dlpar operations, Use device_online() and
> device_offline() instead of cpu_up() and cpu_down().
> 
> Calling cpu_up/down directly does not update the cpu device offline
> field, which is used to online/offline a cpu from sysfs.  Calling
> device_online/offline instead keeps the sysfs cpu online value correct.
> The hotplug lock, which is required to be held when calling
> device_online/offline, is already held when dlpar_online/offline_cpu
> are called, since they are called only from cpu_probe|release_store.
> 
> This patch fixes errors on PowerVM systems that have cpu(s) added/removed
> using dlpar operations; without this patch, the
> /sys/devices/system/cpu/cpuN/online nodes do not correctly show the
> online state of added/removed cpus.
> 
> Signed-off-by: Dan Streetman <ddstreet@ieee.org>
> Cc: Nathan Fontenot <nfont@linux.vnet.ibm.com>

Acked-by: Nathan Fontenot <nfont@linux.vnet.ibm.com>

> ---
> 
> Previous discussion for this:
> https://lkml.org/lkml/2014/10/29/839
> 
>  arch/powerpc/platforms/pseries/dlpar.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/powerpc/platforms/pseries/dlpar.c b/arch/powerpc/platforms/pseries/dlpar.c
> index 6ad83bd..c22bb1b 100644
> --- a/arch/powerpc/platforms/pseries/dlpar.c
> +++ b/arch/powerpc/platforms/pseries/dlpar.c
> @@ -382,7 +382,7 @@ static int dlpar_online_cpu(struct device_node *dn)
>  			BUG_ON(get_cpu_current_state(cpu)
>  					!= CPU_STATE_OFFLINE);
>  			cpu_maps_update_done();
> -			rc = cpu_up(cpu);
> +			rc = device_online(get_cpu_device(cpu));
>  			if (rc)
>  				goto out;
>  			cpu_maps_update_begin();
> @@ -467,7 +467,7 @@ static int dlpar_offline_cpu(struct device_node *dn)
>  			if (get_cpu_current_state(cpu) == CPU_STATE_ONLINE) {
>  				set_preferred_offline_state(cpu, CPU_STATE_OFFLINE);
>  				cpu_maps_update_done();
> -				rc = cpu_down(cpu);
> +				rc = device_offline(get_cpu_device(cpu));
>  				if (rc)
>  					goto out;
>  				cpu_maps_update_begin();
>