diff options
Diffstat (limited to 'Documentation/filesystems/sysfs.txt')
| -rw-r--r-- | Documentation/filesystems/sysfs.txt | 16 |
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, |