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Date: Mon, 20 May 2013 10:09:29 +0530
From: Viresh Kumar <viresh.kumar@...aro.org>
To: Francesco Lavra <francescolavra.fl@...il.com>
Cc: rjw@...k.pl, robin.randhawa@....com, linux-pm@...r.kernel.org,
patches@...aro.org, Liviu.Dudau@....com,
linux-kernel@...r.kernel.org, cpufreq@...r.kernel.org,
linaro-kernel@...ts.linaro.org, Steve.Bannister@....com,
arvind.chauhan@....com, charles.garcia-tobin@....com
Subject: Re: [PATCH 2/2] cpufreq: Don't create empty /sys/devices/system/cpu/cpufreq
directory
On 20 May 2013 00:13, Francesco Lavra <francescolavra.fl@...il.com> wrote:
> On 05/17/2013 01:26 PM, Viresh Kumar wrote:
>> +EXPORT_SYMBOL(get_cpufreq_global_kobject);
>> +EXPORT_SYMBOL(put_cpufreq_global_kobject);
>
> Global symbol names should begin with a sensible prefix; in this case,
> it looks like cpufreq_get_global_kobject and cpufreq_put_global_kobject
> would be more appropriate names.
Please see if V2 looks fine. Attached too for applying.
------------x--------------------x------------------
From: Viresh Kumar <viresh.kumar@...aro.org>
Date: Fri, 17 May 2013 16:09:09 +0530
Subject: [PATCH V2] cpufreq: Don't create empty /sys/devices/system/cpu/cpufreq
directory
When we don't have any file in cpu/cpufreq directory we shouldn't create it.
Specially with the introduction of per-policy governor instance patchset, even
governors are moved to cpu/cpu*/cpufreq/governor-name directory and so this
directory is just not required.
Lets have it only when required.
Signed-off-by: Viresh Kumar <viresh.kumar@...aro.org>
---
V1->V2: Replace: {get|put}_cpufreq_global_kobject with
cpufreq_{get|put}_global_kobject.
drivers/cpufreq/acpi-cpufreq.c | 4 ++--
drivers/cpufreq/cpufreq.c | 48 ++++++++++++++++++++++++++++++++++----
drivers/cpufreq/cpufreq_governor.c | 6 +++++
include/linux/cpufreq.h | 4 ++++
4 files changed, 56 insertions(+), 6 deletions(-)
diff --git a/drivers/cpufreq/acpi-cpufreq.c b/drivers/cpufreq/acpi-cpufreq.c
index ce28c34..ae0918d 100644
--- a/drivers/cpufreq/acpi-cpufreq.c
+++ b/drivers/cpufreq/acpi-cpufreq.c
@@ -947,7 +947,7 @@ static void __init acpi_cpufreq_boost_init(void)
/* We create the boost file in any case, though for systems without
* hardware support it will be read-only and hardwired to return 0.
*/
- if (sysfs_create_file(cpufreq_global_kobject, &(global_boost.attr)))
+ if (cpufreq_sysfs_create_file(&(global_boost.attr)))
pr_warn(PFX "could not register global boost sysfs file\n");
else
pr_debug("registered global boost sysfs file\n");
@@ -955,7 +955,7 @@ static void __init acpi_cpufreq_boost_init(void)
static void __exit acpi_cpufreq_boost_exit(void)
{
- sysfs_remove_file(cpufreq_global_kobject, &(global_boost.attr));
+ cpufreq_sysfs_remove_file(&(global_boost.attr));
if (msrs) {
unregister_cpu_notifier(&boost_nb);
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index e3d7112..74a1a60 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -678,9 +678,6 @@ static struct attribute *default_attrs[] = {
NULL
};
-struct kobject *cpufreq_global_kobject;
-EXPORT_SYMBOL(cpufreq_global_kobject);
-
#define to_policy(k) container_of(k, struct cpufreq_policy, kobj)
#define to_attr(a) container_of(a, struct freq_attr, attr)
@@ -751,6 +748,49 @@ static struct kobj_type ktype_cpufreq = {
.release = cpufreq_sysfs_release,
};
+struct kobject *cpufreq_global_kobject;
+EXPORT_SYMBOL(cpufreq_global_kobject);
+
+static int cpufreq_global_kobject_usage;
+
+int cpufreq_get_global_kobject(void)
+{
+ if (!cpufreq_global_kobject_usage++)
+ return kobject_add(cpufreq_global_kobject,
+ &cpu_subsys.dev_root->kobj, "%s", "cpufreq");
+
+ return 0;
+}
+EXPORT_SYMBOL(cpufreq_get_global_kobject);
+
+void cpufreq_put_global_kobject(void)
+{
+ if (!--cpufreq_global_kobject_usage)
+ kobject_del(cpufreq_global_kobject);
+}
+EXPORT_SYMBOL(cpufreq_put_global_kobject);
+
+int cpufreq_sysfs_create_file(const struct attribute *attr)
+{
+ int ret = cpufreq_get_global_kobject();
+
+ if (!ret) {
+ ret = sysfs_create_file(cpufreq_global_kobject, attr);
+ if (ret)
+ cpufreq_put_global_kobject();
+ }
+
+ return ret;
+}
+EXPORT_SYMBOL(cpufreq_sysfs_create_file);
+
+void cpufreq_sysfs_remove_file(const struct attribute *attr)
+{
+ sysfs_remove_file(cpufreq_global_kobject, attr);
+ cpufreq_put_global_kobject();
+}
+EXPORT_SYMBOL(cpufreq_sysfs_remove_file);
+
/* symlink affected CPUs */
static int cpufreq_add_dev_symlink(unsigned int cpu,
struct cpufreq_policy *policy)
@@ -2022,7 +2062,7 @@ static int __init cpufreq_core_init(void)
init_rwsem(&per_cpu(cpu_policy_rwsem, cpu));
}
- cpufreq_global_kobject = kobject_create_and_add("cpufreq",
&cpu_subsys.dev_root->kobj);
+ cpufreq_global_kobject = kobject_create();
BUG_ON(!cpufreq_global_kobject);
register_syscore_ops(&cpufreq_syscore_ops);
diff --git a/drivers/cpufreq/cpufreq_governor.c
b/drivers/cpufreq/cpufreq_governor.c
index b6cfd55..7532570 100644
--- a/drivers/cpufreq/cpufreq_governor.c
+++ b/drivers/cpufreq/cpufreq_governor.c
@@ -231,6 +231,9 @@ int cpufreq_governor_dbs(struct cpufreq_policy *policy,
return rc;
}
+ if (!have_governor_per_policy())
+ WARN_ON(cpufreq_get_global_kobject());
+
rc = sysfs_create_group(get_governor_parent_kobj(policy),
get_sysfs_attr(dbs_data));
if (rc) {
@@ -269,6 +272,9 @@ int cpufreq_governor_dbs(struct cpufreq_policy *policy,
sysfs_remove_group(get_governor_parent_kobj(policy),
get_sysfs_attr(dbs_data));
+ if (!have_governor_per_policy())
+ cpufreq_put_global_kobject();
+
if ((dbs_data->cdata->governor == GOV_CONSERVATIVE) &&
(policy->governor->initialized == 1)) {
struct cs_ops *cs_ops = dbs_data->cdata->gov_ops;
diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h
index cbdf5a4..b97d99b 100644
--- a/include/linux/cpufreq.h
+++ b/include/linux/cpufreq.h
@@ -71,6 +71,10 @@ struct cpufreq_governor;
/* /sys/devices/system/cpu/cpufreq: entry point for global variables */
extern struct kobject *cpufreq_global_kobject;
+int cpufreq_get_global_kobject(void);
+void cpufreq_put_global_kobject(void);
+int cpufreq_sysfs_create_file(const struct attribute *attr);
+void cpufreq_sysfs_remove_file(const struct attribute *attr);
#define CPUFREQ_ETERNAL (-1)
struct cpufreq_cpuinfo {
Download attachment "0001-cpufreq-Don-t-create-empty-sys-devices-system-cpu-cp.patch" of type "application/octet-stream" (5537 bytes)
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