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[CPUFREQ] CPU hotplug, re-create sysfs directory and symlinks

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When we discover CPUs that are affected by each other's
frequency/voltage transitions, the first CPU gets a sysfs directory
created, and rest of the siblings get symlinks. Currently, when we
hotplug off only the first CPU, all of the symlinks and the sysfs
directory gets removed. Even though rest of the siblings are still
online and functional, they are orphaned, and no longer governed by
cpufreq.

This patch, given the above scenario, creates a sysfs directory for
the first sibling and symlinks for the rest of the siblings.

Please note the recursive call, it was rather too ugly to roll it
out. And the removal of redundant NULL setting (it is already taken
care of near the top of the function).

Signed-off-by: Jacob Shin <jacob.shin@amd.com>
Acked-by: Mark Langsdorf <mark.langsdorf@amd.com>
Reviewed-by: Thomas Renninger <trenn@suse.de>
Signed-off-by: Dave Jones <davej@redhat.com>
Cc: stable@kernel.org
This commit is contained in:
Jacob Shin 2011-04-27 13:32:11 -05:00 committed by Dave Jones
parent 904cc1e637
commit 27ecddc2a9
1 changed files with 18 additions and 2 deletions
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20
drivers/cpufreq/cpufreq.c
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@ -1208,12 +1208,28 @@ static int __cpufreq_remove_dev(struct sys_device *sys_dev)
cpufreq_driver->exit(data); cpufreq_driver->exit(data);
unlock_policy_rwsem_write(cpu); unlock_policy_rwsem_write(cpu);
cpufreq_debug_enable_ratelimit();
#ifdef CONFIG_HOTPLUG_CPU
/* when the CPU which is the parent of the kobj is hotplugged
* offline, check for siblings, and create cpufreq sysfs interface
* and symlinks
*/
if (unlikely(cpumask_weight(data->cpus) > 1)) {
/* first sibling now owns the new sysfs dir */
cpumask_clear_cpu(cpu, data->cpus);
cpufreq_add_dev(get_cpu_sysdev(cpumask_first(data->cpus)));
/* finally remove our own symlink */
lock_policy_rwsem_write(cpu);
__cpufreq_remove_dev(sys_dev);
}
#endif
free_cpumask_var(data->related_cpus); free_cpumask_var(data->related_cpus);
free_cpumask_var(data->cpus); free_cpumask_var(data->cpus);
kfree(data); kfree(data);
per_cpu(cpufreq_cpu_data, cpu) = NULL;
cpufreq_debug_enable_ratelimit();
return 0; return 0;
} }