admin/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux.git synced 2025-12-07 20:06:24 +00:00
Code Issues Packages Projects Releases Wiki Activity

samples/kobject: constify 'struct foo_attribute'

Browse Source 
Showcase and test the new 'struct attribute' constification facilities.

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Link: https://patch.msgid.link/20251029-sysfs-const-attr-prep-v5-6-ea7d745acff4@weissschuh.net
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Thomas Weißschuh
2025-10-29 09:12:15 +01:00
committed by Greg Kroah-Hartman
parent c301a2e2d7
commit 2d76fdc1c9
1 changed files with 17 additions and 16 deletions
Download Patch File Download Diff File Expand all files Collapse all files

33
samples/kobject/kset-example.c
View File

@@ -37,10 +37,11 @@ struct foo_obj {
/* a custom attribute that works just for a struct foo_obj. */
struct foo_attribute {
struct attribute attr;
ssize_t (*show)(struct foo_obj *foo, struct foo_attribute *attr, char *buf);
ssize_t (*store)(struct foo_obj *foo, struct foo_attribute *attr, const char *buf, size_t count);
ssize_t (*show)(struct foo_obj *foo, const struct foo_attribute *attr, char *buf);
ssize_t (*store)(struct foo_obj *foo, const struct foo_attribute *attr,
const char *buf, size_t count);
};
#define to_foo_attr(x) container_of(x, struct foo_attribute, attr)
#define to_foo_attr(x) container_of_const(x, struct foo_attribute, attr)
/*
* The default show function that must be passed to sysfs. This will be
@@ -53,7 +54,7 @@ static ssize_t foo_attr_show(struct kobject *kobj,
struct attribute *attr,
char *buf)
{
struct foo_attribute *attribute;
const struct foo_attribute *attribute;
struct foo_obj *foo;
attribute = to_foo_attr(attr);
@@ -73,7 +74,7 @@ static ssize_t foo_attr_store(struct kobject *kobj,
struct attribute *attr,
const char *buf, size_t len)
{
struct foo_attribute *attribute;
const struct foo_attribute *attribute;
struct foo_obj *foo;
attribute = to_foo_attr(attr);
@@ -109,13 +110,13 @@ static void foo_release(struct kobject *kobj)
/*
* The "foo" file where the .foo variable is read from and written to.
*/
static ssize_t foo_show(struct foo_obj *foo_obj, struct foo_attribute *attr,
static ssize_t foo_show(struct foo_obj *foo_obj, const struct foo_attribute *attr,
char *buf)
{
return sysfs_emit(buf, "%d\n", foo_obj->foo);
}
static ssize_t foo_store(struct foo_obj *foo_obj, struct foo_attribute *attr,
static ssize_t foo_store(struct foo_obj *foo_obj, const struct foo_attribute *attr,
const char *buf, size_t count)
{
int ret;
@@ -128,14 +129,14 @@ static ssize_t foo_store(struct foo_obj *foo_obj, struct foo_attribute *attr,
}
/* Sysfs attributes cannot be world-writable. */
static struct foo_attribute foo_attribute =
static const struct foo_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 foo_obj *foo_obj, struct foo_attribute *attr,
static ssize_t b_show(struct foo_obj *foo_obj, const struct foo_attribute *attr,
char *buf)
{
int var;
@@ -147,7 +148,7 @@ static ssize_t b_show(struct foo_obj *foo_obj, struct foo_attribute *attr,
return sysfs_emit(buf, "%d\n", var);
}
static ssize_t b_store(struct foo_obj *foo_obj, struct foo_attribute *attr,
static ssize_t b_store(struct foo_obj *foo_obj, const struct foo_attribute *attr,
const char *buf, size_t count)
{
int var, ret;
@@ -163,16 +164,16 @@ static ssize_t b_store(struct foo_obj *foo_obj, struct foo_attribute *attr,
return count;
}
static struct foo_attribute baz_attribute =
static const struct foo_attribute baz_attribute =
__ATTR(baz, 0664, b_show, b_store);
static struct foo_attribute bar_attribute =
static const struct foo_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 *foo_default_attrs[] = {
static const struct attribute *const foo_default_attrs[] = {
&foo_attribute.attr,
&baz_attribute.attr,
&bar_attribute.attr,
@@ -180,7 +181,7 @@ static struct attribute *foo_default_attrs[] = {
};
static umode_t foo_default_attrs_is_visible(struct kobject *kobj,
struct attribute *attr,
const struct attribute *attr,
int n)
{
/* Hide attributes with the same name as the kobject. */
@@ -190,8 +191,8 @@ static umode_t foo_default_attrs_is_visible(struct kobject *kobj,
}
static const struct attribute_group foo_default_group = {
.attrs = foo_default_attrs,
.is_visible = foo_default_attrs_is_visible,
.attrs_const = foo_default_attrs,
.is_visible_const = foo_default_attrs_is_visible,
};
__ATTRIBUTE_GROUPS(foo_default);