From: Scott Moser <smoser@redhat.com>
Date: Tue, 20 Nov 2007 17:29:38 -0500
Subject: [ppc64] sysfs: support for add/remove cpu sysfs attr
Message-id: 11955977801330-do-send-email-smoser@redhat.com
O-Subject: [PATCH RHEL5u2] bz279171 Cell/B.E. Power and Thermal Management [3/4]
Bugzilla: 279171

commit 0344c6c5387ba335bba5a66fd44714b94c98573f

Subject: sysfs: add support for adding/removing cpu sysfs attribute groups

From: Christian Krafft <krafft@linux.ibm.com>
This patch adds two functions to create and remove sysfs attribute groups to
all cpus.  That allows to register sysfs attributes in a subdirectory like:
/sys/devices/system/cpu/cpuX/group_name/what_ever

This will be used by cbe_thermal to group all attributes dealing with
thermal support in one directory.

Signed-of-by: Christian Krafft <krafft@de.ibm.com>

--
 arch/powerpc/kernel/sysfs.c |   40 ++++++++++++++++++++++++++++++++++++++
 include/linux/cpu.h         |    4 +++
 2 files changed, 44 insertions(+)

Acked-by: David Howells <dhowells@redhat.com>

diff --git a/arch/powerpc/kernel/sysfs.c b/arch/powerpc/kernel/sysfs.c
index c615575..b1ca7e2 100644
--- a/arch/powerpc/kernel/sysfs.c
+++ b/arch/powerpc/kernel/sysfs.c
@@ -299,6 +299,46 @@ static struct notifier_block __cpuinitdata sysfs_cpu_nb = {
 	.notifier_call	= sysfs_cpu_notify,
 };
 
+static DEFINE_MUTEX(cpu_mutex);
+
+int cpu_add_sysdev_attr_group(struct attribute_group *attrs)
+{
+        int cpu;
+        struct sys_device *sysdev;
+        int error = 0, rc = 0;
+
+        mutex_lock(&cpu_mutex);
+
+        for_each_possible_cpu(cpu) {
+                sysdev = get_cpu_sysdev(cpu);
+                error = sysfs_create_group(&sysdev->kobj, attrs);
+
+		if(error)
+			rc = error;
+        }
+
+        mutex_unlock(&cpu_mutex);
+        return rc;
+}
+EXPORT_SYMBOL_GPL(cpu_add_sysdev_attr_group);
+
+void cpu_remove_sysdev_attr_group(struct attribute_group *attrs)
+{
+        int cpu;
+        struct sys_device *sysdev;
+
+        mutex_lock(&cpu_mutex);
+
+        for_each_possible_cpu(cpu) {
+                sysdev = get_cpu_sysdev(cpu);
+                sysfs_remove_group(&sysdev->kobj, attrs);
+        }
+
+        mutex_unlock(&cpu_mutex);
+}
+EXPORT_SYMBOL_GPL(cpu_remove_sysdev_attr_group);
+
+
 /* NUMA stuff */
 
 #ifdef CONFIG_NUMA
diff --git a/include/linux/cpu.h b/include/linux/cpu.h
index 3fef7d6..c0e1682 100644
--- a/include/linux/cpu.h
+++ b/include/linux/cpu.h
@@ -33,6 +33,10 @@ struct cpu {
 
 extern int register_cpu(struct cpu *cpu, int num);
 extern struct sys_device *get_cpu_sysdev(unsigned cpu);
+
+extern int cpu_add_sysdev_attr_group(struct attribute_group *attrs);
+extern void cpu_remove_sysdev_attr_group(struct attribute_group *attrs);
+
 #ifdef CONFIG_HOTPLUG_CPU
 extern void unregister_cpu(struct cpu *cpu);
 #endif