linux/drivers/base/topology.c
Heiko Carstens 06a4bcae1f cpu topology: consider sysfs_create_group return value
Take return value of sysfs_create_group() into account.  That function got
called in case of CPU_ONLINE notification.  Since callbacks are not allowed
to fail on CPU_ONLINE notification do the sysfs group creation on
CPU_UP_PREPARE notification.

Also remember if creation succeeded in a bitmask.  So it's possible to know
whether it's legal to call sysfs_remove_group or not.

In addition some other minor stuff:

- since CPU_UP_PREPARE might fail add CPU_UP_CANCELED handling as well.
- use hotcpu_notifier instead of register_hotcpu_notifier.
- #ifdef code that isn't needed in the !CONFIG_HOTPLUG_CPU case.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2006-12-01 14:52:01 -08:00

157 lines
3.9 KiB
C

/*
* driver/base/topology.c - Populate sysfs with cpu topology information
*
* Written by: Zhang Yanmin, Intel Corporation
*
* Copyright (C) 2006, Intel Corp.
*
* All rights reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
* NON INFRINGEMENT. See the GNU General Public License for more
* details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*
*/
#include <linux/sysdev.h>
#include <linux/init.h>
#include <linux/mm.h>
#include <linux/cpu.h>
#include <linux/module.h>
#include <linux/topology.h>
#define define_one_ro(_name) \
static SYSDEV_ATTR(_name, 0444, show_##_name, NULL)
#define define_id_show_func(name) \
static ssize_t show_##name(struct sys_device *dev, char *buf) \
{ \
unsigned int cpu = dev->id; \
return sprintf(buf, "%d\n", topology_##name(cpu)); \
}
#define define_siblings_show_func(name) \
static ssize_t show_##name(struct sys_device *dev, char *buf) \
{ \
ssize_t len = -1; \
unsigned int cpu = dev->id; \
len = cpumask_scnprintf(buf, NR_CPUS+1, topology_##name(cpu)); \
return (len + sprintf(buf + len, "\n")); \
}
#ifdef topology_physical_package_id
define_id_show_func(physical_package_id);
define_one_ro(physical_package_id);
#define ref_physical_package_id_attr &attr_physical_package_id.attr,
#else
#define ref_physical_package_id_attr
#endif
#ifdef topology_core_id
define_id_show_func(core_id);
define_one_ro(core_id);
#define ref_core_id_attr &attr_core_id.attr,
#else
#define ref_core_id_attr
#endif
#ifdef topology_thread_siblings
define_siblings_show_func(thread_siblings);
define_one_ro(thread_siblings);
#define ref_thread_siblings_attr &attr_thread_siblings.attr,
#else
#define ref_thread_siblings_attr
#endif
#ifdef topology_core_siblings
define_siblings_show_func(core_siblings);
define_one_ro(core_siblings);
#define ref_core_siblings_attr &attr_core_siblings.attr,
#else
#define ref_core_siblings_attr
#endif
static struct attribute *default_attrs[] = {
ref_physical_package_id_attr
ref_core_id_attr
ref_thread_siblings_attr
ref_core_siblings_attr
NULL
};
static struct attribute_group topology_attr_group = {
.attrs = default_attrs,
.name = "topology"
};
static cpumask_t topology_dev_map = CPU_MASK_NONE;
/* Add/Remove cpu_topology interface for CPU device */
static int __cpuinit topology_add_dev(unsigned int cpu)
{
int rc;
struct sys_device *sys_dev = get_cpu_sysdev(cpu);
rc = sysfs_create_group(&sys_dev->kobj, &topology_attr_group);
if (!rc)
cpu_set(cpu, topology_dev_map);
return rc;
}
#ifdef CONFIG_HOTPLUG_CPU
static void __cpuinit topology_remove_dev(unsigned int cpu)
{
struct sys_device *sys_dev = get_cpu_sysdev(cpu);
if (!cpu_isset(cpu, topology_dev_map))
return;
cpu_clear(cpu, topology_dev_map);
sysfs_remove_group(&sys_dev->kobj, &topology_attr_group);
}
static int __cpuinit topology_cpu_callback(struct notifier_block *nfb,
unsigned long action, void *hcpu)
{
unsigned int cpu = (unsigned long)hcpu;
int rc = 0;
switch (action) {
case CPU_UP_PREPARE:
rc = topology_add_dev(cpu);
break;
case CPU_UP_CANCELED:
case CPU_DEAD:
topology_remove_dev(cpu);
break;
}
return rc ? NOTIFY_BAD : NOTIFY_OK;
}
#endif
static int __cpuinit topology_sysfs_init(void)
{
int cpu;
int rc;
for_each_online_cpu(cpu) {
rc = topology_add_dev(cpu);
if (rc)
return rc;
}
hotcpu_notifier(topology_cpu_callback, 0);
return 0;
}
device_initcall(topology_sysfs_init);