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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>
This commit is contained in:
Takashi Iwai 2015-02-05 21:38:58 +01:00 committed by David Vrabel
parent 06e5801b8c
commit 4644e5ab06
1 changed files with 28 additions and 16 deletions
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44
drivers/xen/pcpu.c
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@ -132,6 +132,33 @@ static ssize_t __ref store_online(struct device *dev,
}
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 @@ static void unregister_and_remove_pcpu(struct pcpu *pcpu)
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 @@ static int register_pcpu(struct pcpu *pcpu)
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 @@ static int register_pcpu(struct pcpu *pcpu)
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;
}