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-rw-r--r--Documentation/filesystems/sysfs.txt16
1 files changed, 9 insertions, 7 deletions
diff --git a/Documentation/filesystems/sysfs.txt b/Documentation/filesystems/sysfs.txt
index 5d1335faec2d..f806e50aaa63 100644
--- a/Documentation/filesystems/sysfs.txt
+++ b/Documentation/filesystems/sysfs.txt
@@ -39,10 +39,12 @@ userspace. Top-level directories in sysfs represent the common
ancestors of object hierarchies; i.e. the subsystems the objects
belong to.
-Sysfs internally stores the kobject that owns the directory in the
-->d_fsdata pointer of the directory's dentry. This allows sysfs to do
-reference counting directly on the kobject when the file is opened and
-closed.
+Sysfs internally stores a pointer to the kobject that implements a
+directory in the sysfs_dirent object associated with the directory. In
+the past this kobject pointer has been used by sysfs to do reference
+counting directly on the kobject whenever the file is opened or closed.
+With the current sysfs implementation the kobject reference count is
+only modified directly by the function sysfs_schedule_callback().
Attributes
@@ -208,9 +210,9 @@ Other notes:
is 4096.
- show() methods should return the number of bytes printed into the
- buffer. This is the return value of snprintf().
+ buffer. This is the return value of scnprintf().
-- show() should always use snprintf().
+- show() should always use scnprintf().
- store() should return the number of bytes used from the buffer. If the
entire buffer has been used, just return the count argument.
@@ -229,7 +231,7 @@ A very simple (and naive) implementation of a device attribute is:
static ssize_t show_name(struct device *dev, struct device_attribute *attr,
char *buf)
{
- return snprintf(buf, PAGE_SIZE, "%s\n", dev->name);
+ return scnprintf(buf, PAGE_SIZE, "%s\n", dev->name);
}
static ssize_t store_name(struct device *dev, struct device_attribute *attr,