cpuidle: Make cpuidle's sysfs directory dynamically allocated

The cpuidle sysfs code is designed to have a single instance of per
CPU cpuidle directory.  It is not possible to remove the sysfs entry
and create it again.  This is not a problem with the current code but
future changes will add CPU hotplug support to enable/disable the
device, so it will need to remove the sysfs entry like other
subsystems do.  That won't be possible without this change, because
the kobj is a static object which can't be reused for
kobj_init_and_add().

Add cpuidle_device_kobj to be allocated dynamically when
adding/removing a sysfs entry which is consistent with the other
cpuidle's sysfs entries.

An added benefit is that the sysfs code is now more self-contained
and the includes needed for sysfs can be moved from cpuidle.h
directly into sysfs.c so as to reduce the total number of headers
dragged along with cpuidle.h.

[rjw: Changelog]
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

1 files changed, 48 insertions, 15 deletions

diff --git a/drivers/cpuidle/sysfs.c b/drivers/cpuidle/sysfs.c
index 7d4448a9fbbd..8739cc05228c 100644
--- a/drivers/cpuidle/sysfs.c
+++ b/drivers/cpuidle/sysfs.c
@@ -11,8 +11,10 @@
 #include <linux/sysfs.h>
 #include <linux/slab.h>
 #include <linux/cpu.h>
+#include <linux/completion.h>
 #include <linux/capability.h>
 #include <linux/device.h>
+#include <linux/kobject.h>
 
 #include "cpuidle.h"
 
@@ -167,14 +169,27 @@ struct cpuidle_attr {
 #define define_one_rw(_name, show, store) \
         static struct cpuidle_attr attr_##_name = __ATTR(_name, 0644, show, store)
 
-#define kobj_to_cpuidledev(k) container_of(k, struct cpuidle_device, kobj)
 #define attr_to_cpuidleattr(a) container_of(a, struct cpuidle_attr, attr)
 
+struct cpuidle_device_kobj {
+        struct cpuidle_device *dev;
+        struct completion kobj_unregister;
+        struct kobject kobj;
+};
+
+static inline struct cpuidle_device *to_cpuidle_device(struct kobject *kobj)
+{
+        struct cpuidle_device_kobj *kdev =
+                container_of(kobj, struct cpuidle_device_kobj, kobj);
+
+        return kdev->dev;
+}
+
 static ssize_t cpuidle_show(struct kobject *kobj, struct attribute *attr,
                             char *buf)
 {
         int ret = -EIO;
-        struct cpuidle_device *dev = kobj_to_cpuidledev(kobj);
+        struct cpuidle_device *dev = to_cpuidle_device(kobj);
         struct cpuidle_attr *cattr = attr_to_cpuidleattr(attr);
 
         if (cattr->show) {
@@ -189,7 +204,7 @@ static ssize_t cpuidle_store(struct kobject *kobj, struct attribute *attr,
                              const char *buf, size_t count)
 {
         int ret = -EIO;
-        struct cpuidle_device *dev = kobj_to_cpuidledev(kobj);
+        struct cpuidle_device *dev = to_cpuidle_device(kobj);
         struct cpuidle_attr *cattr = attr_to_cpuidleattr(attr);
 
         if (cattr->store) {
@@ -207,9 +222,10 @@ static const struct sysfs_ops cpuidle_sysfs_ops = {
 
 static void cpuidle_sysfs_release(struct kobject *kobj)
 {
-        struct cpuidle_device *dev = kobj_to_cpuidledev(kobj);
+        struct cpuidle_device_kobj *kdev =
+                container_of(kobj, struct cpuidle_device_kobj, kobj);
 
-        complete(&dev->kobj_unregister);
+        complete(&kdev->kobj_unregister);
 }
 
 static struct kobj_type ktype_cpuidle = {
@@ -377,6 +393,7 @@ static int cpuidle_add_state_sysfs(struct cpuidle_device *device)
 {
         int i, ret = -ENOMEM;
         struct cpuidle_state_kobj *kobj;
+        struct cpuidle_device_kobj *kdev = device->kobj_dev;
         struct cpuidle_driver *drv = cpuidle_get_cpu_driver(device);
 
         /* state statistics */
@@ -389,7 +406,7 @@ static int cpuidle_add_state_sysfs(struct cpuidle_device *device)
                 init_completion(&kobj->kobj_unregister);
 
                 ret = kobject_init_and_add(&kobj->kobj, &ktype_state_cpuidle,
-                                           &device->kobj, "state%d", i);
+                                           &kdev->kobj, "state%d", i);
                 if (ret) {
                         kfree(kobj);
                         goto error_state;
@@ -506,6 +523,7 @@ static struct kobj_type ktype_driver_cpuidle = {
 static int cpuidle_add_driver_sysfs(struct cpuidle_device *dev)
 {
         struct cpuidle_driver_kobj *kdrv;
+        struct cpuidle_device_kobj *kdev = dev->kobj_dev;
         struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev);
         int ret;
 
@@ -517,7 +535,7 @@ static int cpuidle_add_driver_sysfs(struct cpuidle_device *dev)
         init_completion(&kdrv->kobj_unregister);
 
         ret = kobject_init_and_add(&kdrv->kobj, &ktype_driver_cpuidle,
-                                   &dev->kobj, "driver");
+                                   &kdev->kobj, "driver");
         if (ret) {
                 kfree(kdrv);
                 return ret;
@@ -586,16 +604,28 @@ void cpuidle_remove_device_sysfs(struct cpuidle_device *device)
  */
 int cpuidle_add_sysfs(struct cpuidle_device *dev)
 {
+        struct cpuidle_device_kobj *kdev;
         struct device *cpu_dev = get_cpu_device((unsigned long)dev->cpu);
         int error;
 
-        init_completion(&dev->kobj_unregister);
+        kdev = kzalloc(sizeof(*kdev), GFP_KERNEL);
+        if (!kdev)
+                return -ENOMEM;
+        kdev->dev = dev;
+        dev->kobj_dev = kdev;
+
+        init_completion(&kdev->kobj_unregister);
+
+        error = kobject_init_and_add(&kdev->kobj, &ktype_cpuidle, &cpu_dev->kobj,
+                                   "cpuidle");
+        if (error) {
+                kfree(kdev);
+                return error;
+        }
 
-        error = kobject_init_and_add(&dev->kobj, &ktype_cpuidle, &cpu_dev->kobj,
-                                     "cpuidle");
-        if (!error)
-                kobject_uevent(&dev->kobj, KOBJ_ADD);
-        return error;
+        kobject_uevent(&kdev->kobj, KOBJ_ADD);
+
+        return 0;
 }
 
 /**
@@ -604,6 +634,9 @@ int cpuidle_add_sysfs(struct cpuidle_device *dev)
  */
 void cpuidle_remove_sysfs(struct cpuidle_device *dev)
 {
-        kobject_put(&dev->kobj);
-        wait_for_completion(&dev->kobj_unregister);
+        struct cpuidle_device_kobj *kdev = dev->kobj_dev;
+
+        kobject_put(&kdev->kobj);
+        wait_for_completion(&kdev->kobj_unregister);
+        kfree(kdev);
 }