linux-kernel - [PATCH] powerpc: use device_online/offline() instead of cpu

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Date:	Fri, 31 Oct 2014 15:41:34 -0400
From:	Dan Streetman <ddstreet@...e.org>
To:	Nathan Fontenot <nfont@...ux.vnet.ibm.com>,
	Benjamin Herrenschmidt <benh@...nel.crashing.org>,
	Michael Ellerman <mpe@...erman.id.au>,
	Tyrel Datwyler <tyreld@...ux.vnet.ibm.com>
Cc:	Dan Streetman <ddstreet@...e.org>,
	Paul Mackerras <paulus@...ba.org>,
	Thomas Falcon <tlfalcon@...ux.vnet.ibm.com>,
	Grant Likely <grant.likely@...aro.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Daniel Walter <dwalter@...gle.com>,
	Bharata B Rao <bharata@...ux.vnet.ibm.com>,
	"Rafael J. Wysocki" <rafael.j.wysocki@...el.com>,
	"Rafael J. Wysocki" <rjw@...ysocki.net>,
	Neil Zhang <zhangwm@...vell.com>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	linuxppc-dev@...ts.ozlabs.org, linux-kernel@...r.kernel.org
Subject: [PATCH] powerpc: use device_online/offline() instead of cpu_up/down()

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@...e.org>
Cc: Nathan Fontenot <nfont@...ux.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();
-- 
1.8.3.1

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