samples/kobject: Use sysfs_emit instead of sprintf

sysfs_emit() is preferred over sprintf() when formatting the value to be
returned to user space in show() functions, because it knows about sysfs
buffer specifics and has sanity checks.

Signed-off-by: Nguyen Dinh Phi <phind.uet@gmail.com>
Link: https://lore.kernel.org/r/20220303183618.1342358-1-phind.uet@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: phi-nguyendp

samples/kobject/kobject-example.c

@@ -28,7 +28,7 @@ static int bar;
 static ssize_t foo_show(struct kobject *kobj, struct kobj_attribute *attr,
 			char *buf)
 {
-	return sprintf(buf, "%d\n", foo);
+	return sysfs_emit(buf, "%d\n", foo);
 }
 
 static ssize_t foo_store(struct kobject *kobj, struct kobj_attribute *attr,
@@ -60,7 +60,7 @@ static ssize_t b_show(struct kobject *kobj, struct kobj_attribute *attr,
 		var = baz;
 	else
 		var = bar;
-	return sprintf(buf, "%d\n", var);
+	return sysfs_emit(buf, "%d\n", var);
 }
 
 static ssize_t b_store(struct kobject *kobj, struct kobj_attribute *attr,

samples/kobject/kset-example.c

@@ -112,7 +112,7 @@ static void foo_release(struct kobject *kobj)
 static ssize_t foo_show(struct foo_obj *foo_obj, struct foo_attribute *attr,
 			char *buf)
 {
-	return sprintf(buf, "%d\n", foo_obj->foo);
+	return sysfs_emit(buf, "%d\n", foo_obj->foo);
 }
 
 static ssize_t foo_store(struct foo_obj *foo_obj, struct foo_attribute *attr,
@@ -144,7 +144,7 @@ static ssize_t b_show(struct foo_obj *foo_obj, struct foo_attribute *attr,
 		var = foo_obj->baz;
 	else
 		var = foo_obj->bar;
-	return sprintf(buf, "%d\n", var);
+	return sysfs_emit(buf, "%d\n", var);
 }
 
 static ssize_t b_store(struct foo_obj *foo_obj, struct foo_attribute *attr,