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authorAndré Fabian Silva Delgado <emulatorman@parabola.nu>2016-01-20 14:01:31 -0300
committerAndré Fabian Silva Delgado <emulatorman@parabola.nu>2016-01-20 14:01:31 -0300
commitb4b7ff4b08e691656c9d77c758fc355833128ac0 (patch)
tree82fcb00e6b918026dc9f2d1f05ed8eee83874cc0 /Documentation/filesystems/configfs/configfs.txt
parent35acfa0fc609f2a2cd95cef4a6a9c3a5c38f1778 (diff)
Linux-libre 4.4-gnupck-4.4-gnu
Diffstat (limited to 'Documentation/filesystems/configfs/configfs.txt')
-rw-r--r--Documentation/filesystems/configfs/configfs.txt38
1 files changed, 11 insertions, 27 deletions
diff --git a/Documentation/filesystems/configfs/configfs.txt b/Documentation/filesystems/configfs/configfs.txt
index b40fec9d3..af68efdbb 100644
--- a/Documentation/filesystems/configfs/configfs.txt
+++ b/Documentation/filesystems/configfs/configfs.txt
@@ -160,12 +160,6 @@ among other things. For that, it needs a type.
struct configfs_item_operations {
void (*release)(struct config_item *);
- ssize_t (*show_attribute)(struct config_item *,
- struct configfs_attribute *,
- char *);
- ssize_t (*store_attribute)(struct config_item *,
- struct configfs_attribute *,
- const char *, size_t);
int (*allow_link)(struct config_item *src,
struct config_item *target);
int (*drop_link)(struct config_item *src,
@@ -183,9 +177,7 @@ The most basic function of a config_item_type is to define what
operations can be performed on a config_item. All items that have been
allocated dynamically will need to provide the ct_item_ops->release()
method. This method is called when the config_item's reference count
-reaches zero. Items that wish to display an attribute need to provide
-the ct_item_ops->show_attribute() method. Similarly, storing a new
-attribute value uses the store_attribute() method.
+reaches zero.
[struct configfs_attribute]
@@ -193,6 +185,8 @@ attribute value uses the store_attribute() method.
char *ca_name;
struct module *ca_owner;
umode_t ca_mode;
+ ssize_t (*show)(struct config_item *, char *);
+ ssize_t (*store)(struct config_item *, const char *, size_t);
};
When a config_item wants an attribute to appear as a file in the item's
@@ -202,10 +196,10 @@ config_item_type->ct_attrs. When the item appears in configfs, the
attribute file will appear with the configfs_attribute->ca_name
filename. configfs_attribute->ca_mode specifies the file permissions.
-If an attribute is readable and the config_item provides a
-ct_item_ops->show_attribute() method, that method will be called
-whenever userspace asks for a read(2) on the attribute. The converse
-will happen for write(2).
+If an attribute is readable and provides a ->show method, that method will
+be called whenever userspace asks for a read(2) on the attribute. If an
+attribute is writable and provides a ->store method, that method will be
+be called whenever userspace asks for a write(2) on the attribute.
[struct config_group]
@@ -311,20 +305,10 @@ the subsystem must be ready for it.
[An Example]
The best example of these basic concepts is the simple_children
-subsystem/group and the simple_child item in configfs_example_explicit.c
-and configfs_example_macros.c. It shows a trivial object displaying and
-storing an attribute, and a simple group creating and destroying these
-children.
-
-The only difference between configfs_example_explicit.c and
-configfs_example_macros.c is how the attributes of the childless item
-are defined. The childless item has extended attributes, each with
-their own show()/store() operation. This follows a convention commonly
-used in sysfs. configfs_example_explicit.c creates these attributes
-by explicitly defining the structures involved. Conversely
-configfs_example_macros.c uses some convenience macros from configfs.h
-to define the attributes. These macros are similar to their sysfs
-counterparts.
+subsystem/group and the simple_child item in
+samples/configfs/configfs_sample.c. It shows a trivial object displaying
+and storing an attribute, and a simple group creating and destroying
+these children.
[Hierarchy Navigation and the Subsystem Mutex]