Revision 3ddc76dfc786cc6f87852693227fb0b1f124f807 authored by Linus Torvalds on 25 December 2016, 22:30:04 UTC, committed by Linus Torvalds on 25 December 2016, 22:30:04 UTC
Pull timer type cleanups from Thomas Gleixner: "This series does a tree wide cleanup of types related to timers/timekeeping. - Get rid of cycles_t and use a plain u64. The type is not really helpful and caused more confusion than clarity - Get rid of the ktime union. The union has become useless as we use the scalar nanoseconds storage unconditionally now. The 32bit timespec alike storage got removed due to the Y2038 limitations some time ago. That leaves the odd union access around for no reason. Clean it up. Both changes have been done with coccinelle and a small amount of manual mopping up" * 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: ktime: Get rid of ktime_equal() ktime: Cleanup ktime_set() usage ktime: Get rid of the union clocksource: Use a plain u64 instead of cycle_t
kobject-example.c
/*
* Sample kobject implementation
*
* Copyright (C) 2004-2007 Greg Kroah-Hartman <greg@kroah.com>
* Copyright (C) 2007 Novell Inc.
*
* Released under the GPL version 2 only.
*
*/
#include <linux/kobject.h>
#include <linux/string.h>
#include <linux/sysfs.h>
#include <linux/module.h>
#include <linux/init.h>
/*
* This module shows how to create a simple subdirectory in sysfs called
* /sys/kernel/kobject-example In that directory, 3 files are created:
* "foo", "baz", and "bar". If an integer is written to these files, it can be
* later read out of it.
*/
static int foo;
static int baz;
static int bar;
/*
* The "foo" file where a static variable is read from and written to.
*/
static ssize_t foo_show(struct kobject *kobj, struct kobj_attribute *attr,
char *buf)
{
return sprintf(buf, "%d\n", foo);
}
static ssize_t foo_store(struct kobject *kobj, struct kobj_attribute *attr,
const char *buf, size_t count)
{
int ret;
ret = kstrtoint(buf, 10, &foo);
if (ret < 0)
return ret;
return count;
}
/* Sysfs attributes cannot be world-writable. */
static struct kobj_attribute foo_attribute =
__ATTR(foo, 0664, foo_show, foo_store);
/*
* More complex function where we determine which variable is being accessed by
* looking at the attribute for the "baz" and "bar" files.
*/
static ssize_t b_show(struct kobject *kobj, struct kobj_attribute *attr,
char *buf)
{
int var;
if (strcmp(attr->attr.name, "baz") == 0)
var = baz;
else
var = bar;
return sprintf(buf, "%d\n", var);
}
static ssize_t b_store(struct kobject *kobj, struct kobj_attribute *attr,
const char *buf, size_t count)
{
int var, ret;
ret = kstrtoint(buf, 10, &var);
if (ret < 0)
return ret;
if (strcmp(attr->attr.name, "baz") == 0)
baz = var;
else
bar = var;
return count;
}
static struct kobj_attribute baz_attribute =
__ATTR(baz, 0664, b_show, b_store);
static struct kobj_attribute bar_attribute =
__ATTR(bar, 0664, b_show, b_store);
/*
* Create a group of attributes so that we can create and destroy them all
* at once.
*/
static struct attribute *attrs[] = {
&foo_attribute.attr,
&baz_attribute.attr,
&bar_attribute.attr,
NULL, /* need to NULL terminate the list of attributes */
};
/*
* An unnamed attribute group will put all of the attributes directly in
* the kobject directory. If we specify a name, a subdirectory will be
* created for the attributes with the directory being the name of the
* attribute group.
*/
static struct attribute_group attr_group = {
.attrs = attrs,
};
static struct kobject *example_kobj;
static int __init example_init(void)
{
int retval;
/*
* Create a simple kobject with the name of "kobject_example",
* located under /sys/kernel/
*
* As this is a simple directory, no uevent will be sent to
* userspace. That is why this function should not be used for
* any type of dynamic kobjects, where the name and number are
* not known ahead of time.
*/
example_kobj = kobject_create_and_add("kobject_example", kernel_kobj);
if (!example_kobj)
return -ENOMEM;
/* Create the files associated with this kobject */
retval = sysfs_create_group(example_kobj, &attr_group);
if (retval)
kobject_put(example_kobj);
return retval;
}
static void __exit example_exit(void)
{
kobject_put(example_kobj);
}
module_init(example_init);
module_exit(example_exit);
MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("Greg Kroah-Hartman <greg@kroah.com>");
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