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author | Joel Becker <joel.becker@oracle.com> | 2008-06-18 19:29:05 -0700 |
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committer | Mark Fasheh <mfasheh@suse.com> | 2008-07-31 16:21:13 -0700 |
commit | ecb3d28c7edd58b54f16838c434b342ba9195bec (patch) | |
tree | 2babdc068dde924a905b0b25e673be0ca7a7dccd /include/linux/configfs.h | |
parent | 70526b67443a980d5029d9cf06903bef731a4e96 (diff) | |
download | linux-stable-ecb3d28c7edd58b54f16838c434b342ba9195bec.tar.gz linux-stable-ecb3d28c7edd58b54f16838c434b342ba9195bec.tar.bz2 linux-stable-ecb3d28c7edd58b54f16838c434b342ba9195bec.zip |
[PATCH] configfs: Convenience macros for attribute definition.
Sysfs has the _ATTR() and _ATTR_RO() macros to make defining extended
form attributes easier. configfs should have something similiar.
- _CONFIGFS_ATTR() and _CONFIGFS_ATTR_RO() are the counterparts to the
sysfs macros.
- CONFIGFS_ATTR_STRUCT() creates the extended form attribute structure.
- CONFIGFS_ATTR_OPS() defines the show_attribute()/store_attribute()
operations that call the show()/store() operations of the extended
form configfs_attributes.
Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
Diffstat (limited to 'include/linux/configfs.h')
-rw-r--r-- | include/linux/configfs.h | 67 |
1 files changed, 65 insertions, 2 deletions
diff --git a/include/linux/configfs.h b/include/linux/configfs.h index 0a5491baf0bc..7f627775c947 100644 --- a/include/linux/configfs.h +++ b/include/linux/configfs.h @@ -130,8 +130,25 @@ struct configfs_attribute { /* * Users often need to create attribute structures for their configurable * attributes, containing a configfs_attribute member and function pointers - * for the show() and store() operations on that attribute. They can use - * this macro (similar to sysfs' __ATTR) to make defining attributes easier. + * for the show() and store() operations on that attribute. If they don't + * need anything else on the extended attribute structure, they can use + * this macro to define it The argument _item is the name of the + * config_item structure. + */ +#define CONFIGFS_ATTR_STRUCT(_item) \ +struct _item##_attribute { \ + struct configfs_attribute attr; \ + ssize_t (*show)(struct _item *, char *); \ + ssize_t (*store)(struct _item *, const char *, size_t); \ +} + +/* + * With the extended attribute structure, users can use this macro + * (similar to sysfs' __ATTR) to make defining attributes easier. + * An example: + * #define MYITEM_ATTR(_name, _mode, _show, _store) \ + * struct myitem_attribute childless_attr_##_name = \ + * __CONFIGFS_ATTR(_name, _mode, _show, _store) */ #define __CONFIGFS_ATTR(_name, _mode, _show, _store) \ { \ @@ -143,6 +160,52 @@ struct configfs_attribute { .show = _show, \ .store = _store, \ } +/* Here is a readonly version, only requiring a show() operation */ +#define __CONFIGFS_ATTR_RO(_name, _show) \ +{ \ + .attr = { \ + .ca_name = __stringify(_name), \ + .ca_mode = 0444, \ + .ca_owner = THIS_MODULE, \ + }, \ + .show = _show, \ +} + +/* + * With these extended attributes, the simple show_attribute() and + * store_attribute() operations need to call the show() and store() of the + * attributes. This is a common pattern, so we provide a macro to define + * them. The argument _item is the name of the config_item structure. + * This macro expects the attributes to be named "struct <name>_attribute" + * and the function to_<name>() to exist; + */ +#define CONFIGFS_ATTR_OPS(_item) \ +static ssize_t _item##_attr_show(struct config_item *item, \ + struct configfs_attribute *attr, \ + char *page) \ +{ \ + struct _item *_item = to_##_item(item); \ + struct _item##_attribute *_item##_attr = \ + container_of(attr, struct _item##_attribute, attr); \ + ssize_t ret = 0; \ + \ + if (_item##_attr->show) \ + ret = _item##_attr->show(_item, page); \ + return ret; \ +} \ +static ssize_t _item##_attr_store(struct config_item *item, \ + struct configfs_attribute *attr, \ + const char *page, size_t count) \ +{ \ + struct _item *_item = to_##_item(item); \ + struct _item##_attribute *_item##_attr = \ + container_of(attr, struct _item##_attribute, attr); \ + ssize_t ret = -EINVAL; \ + \ + if (_item##_attr->store) \ + ret = _item##_attr->store(_item, page, count); \ + return ret; \ +} /* * If allow_link() exists, the item can symlink(2) out to other |