sysfs: Document sysfs_attr_init and sysfs_bin_attr_init

I have added a new requirement to the external sysfs interface
that dynamically allocated sysfs attributes must call sysfs_attr_init
if lockdep is enabled.  For the time being callying sysfs_attr_init
is only mandatory if lockdep is enabled, so we can live with a few
unconverted instances until we find them all.  As this is part of
the public interface of sysfs it is a good idea to document these
pseudo functions so someone inspeciting the code can find out
what has happened.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 20 insertions, 0 deletions

diff --git a/include/linux/sysfs.h b/include/linux/sysfs.h
index 006c359e63c0..5b8f80f5aca6 100644
--- a/include/linux/sysfs.h
+++ b/include/linux/sysfs.h
@@ -36,6 +36,16 @@ struct attribute {
 #endif
 };
 
+/**
+ *      sysfs_attr_init - initialize a dynamically allocated sysfs attribute
+ *      @attr: struct attribute to initialize
+ *
+ *      Initialize a dynamically allocated struct attribute so we can
+ *      make lockdep happy.  This is a new requirement for attributes
+ *      and initially this is only needed when lockdep is enabled.
+ *      Lockdep gives a nice error when your attribute is added to
+ *      sysfs if you don't have this.
+ */
 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 #define sysfs_attr_init(attr)                           \
 do {                                                    \
@@ -90,6 +100,16 @@ struct bin_attribute {
                     struct vm_area_struct *vma);
 };
 
+/**
+ *      sysfs_bin_attr_init - initialize a dynamically allocated bin_attribute
+ *      @attr: struct bin_attribute to initialize
+ *
+ *      Initialize a dynamically allocated struct bin_attribute so we
+ *      can make lockdep happy.  This is a new requirement for
+ *      attributes and initially this is only needed when lockdep is
+ *      enabled.  Lockdep gives a nice error when your attribute is
+ *      added to sysfs if you don't have this.
+ */
 #define sysfs_bin_attr_init(bin_attr) sysfs_attr_init(&bin_attr->attr)
 
 struct sysfs_ops {