xen: pcpu: Use static attribute groups for sysfs entry
Instead of manual calls of device_create_file() and
device_remove_file(), assign the static attribute groups to the device
to register. The conditional build of sysfs is done in is_visible
callback instead.
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
diff --git a/drivers/xen/pcpu.c b/drivers/xen/pcpu.c
index 0aac403..49e88f2 100644
--- a/drivers/xen/pcpu.c
+++ b/drivers/xen/pcpu.c
@@ -132,6 +132,33 @@
}
static DEVICE_ATTR(online, S_IRUGO | S_IWUSR, show_online, store_online);
+static struct attribute *pcpu_dev_attrs[] = {
+ &dev_attr_online.attr,
+ NULL
+};
+
+static umode_t pcpu_dev_is_visible(struct kobject *kobj,
+ struct attribute *attr, int idx)
+{
+ struct device *dev = kobj_to_dev(kobj);
+ /*
+ * Xen never offline cpu0 due to several restrictions
+ * and assumptions. This basically doesn't add a sys control
+ * to user, one cannot attempt to offline BSP.
+ */
+ return dev->id ? attr->mode : 0;
+}
+
+static const struct attribute_group pcpu_dev_group = {
+ .attrs = pcpu_dev_attrs,
+ .is_visible = pcpu_dev_is_visible,
+};
+
+static const struct attribute_group *pcpu_dev_groups[] = {
+ &pcpu_dev_group,
+ NULL
+};
+
static bool xen_pcpu_online(uint32_t flags)
{
return !!(flags & XEN_PCPU_FLAGS_ONLINE);
@@ -181,9 +208,6 @@
return;
dev = &pcpu->dev;
- if (dev->id)
- device_remove_file(dev, &dev_attr_online);
-
/* pcpu remove would be implicitly done */
device_unregister(dev);
}
@@ -200,6 +224,7 @@
dev->bus = &xen_pcpu_subsys;
dev->id = pcpu->cpu_id;
dev->release = pcpu_release;
+ dev->groups = pcpu_dev_groups;
err = device_register(dev);
if (err) {
@@ -207,19 +232,6 @@
return err;
}
- /*
- * Xen never offline cpu0 due to several restrictions
- * and assumptions. This basically doesn't add a sys control
- * to user, one cannot attempt to offline BSP.
- */
- if (dev->id) {
- err = device_create_file(dev, &dev_attr_online);
- if (err) {
- device_unregister(dev);
- return err;
- }
- }
-
return 0;
}