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Subject[PATCH -mm 3/3] configfs+dlm: Rename config_group_find_obj and state semantics clearly
From: Satyam Sharma <ssatyam@cse.iitk.ac.in>

[3/3] configfs+dlm: Rename config_group_find_obj and state semantics clearly

[ Ok, this might sound like a gratuitous patch, but I believe there are
good reasons for it. ]

Configfs being based upon sysfs code, config_group_find_obj() is probably
so named because of the similar kset_find_obj() in sysfs. However,
"kobject"s in sysfs become "config_item"s in configfs, so let's call it
config_group_find_item() instead, for sake of uniformity, and make
corresponding change in the users of this function.

BTW a crucial difference between kset_find_obj and config_group_find_item
is in locking expectations. kset_find_obj does its locking by itself, but
config_group_find_item expects the *caller* to do the locking. The reason
for this: kset's have their own locks, config_group's don't but instead
rely on the subsystem mutex. And, subsystem needn't necessarily be around
when config_group_find_item() is called.

So let's state these locking semantics explicitly, and rectify the comment,
otherwise bugs could continue to occur in future, as they did in the past
(refer commit d82b8191e238 in gfs2-2.6-fixes.git).

[ I also took the opportunity to fix some bad whitespace and
double-empty lines. ]

Signed-off-by: Satyam Sharma <ssatyam@cse.iitk.ac.in>
Cc: Joel Becker <joel.becker@oracle.com>
Cc: David Teigland <teigland@redhat.com>

---
fs/configfs/item.c | 18 ++++++++----------
fs/dlm/config.c | 2 +-
include/linux/configfs.h | 8 ++------
3 files changed, 11 insertions(+), 17 deletions(-)
---
diff -ruNp a/fs/configfs/item.c b/fs/configfs/item.c
--- a/fs/configfs/item.c 2007-06-28 17:32:57.000000000 +0530
+++ b/fs/configfs/item.c 2007-07-03 19:42:00.000000000 +0530
@@ -183,27 +183,25 @@ void config_group_init(struct config_gro
INIT_LIST_HEAD(&group->cg_children);
}

-
/**
- * config_group_find_obj - search for item in group.
+ * config_group_find_item - search for item in group.
* @group: group we're looking in.
* @name: item's name.
*
- * Lock group via @group->cg_subsys, and iterate over @group->cg_list,
- * looking for a matching config_item. If matching item is found
- * take a reference and return the item.
+ * Iterate over @group->cg_list, looking for a matching config_item.
+ * If matching item is found take a reference and return the item.
+ * Caller must have locked group via @group->cg_subsys->su_mtx.
*/
-struct config_item *config_group_find_obj(struct config_group *group,
- const char * name)
+struct config_item *config_group_find_item(struct config_group *group,
+ const char *name)
{
struct list_head * entry;
struct config_item * ret = NULL;

- /* XXX LOCKING! */
list_for_each(entry,&group->cg_children) {
struct config_item * item = to_item(entry);
if (config_item_name(item) &&
- !strcmp(config_item_name(item), name)) {
+ !strcmp(config_item_name(item), name)) {
ret = config_item_get(item);
break;
}
@@ -215,4 +213,4 @@ EXPORT_SYMBOL(config_item_init);
EXPORT_SYMBOL(config_group_init);
EXPORT_SYMBOL(config_item_get);
EXPORT_SYMBOL(config_item_put);
-EXPORT_SYMBOL(config_group_find_obj);
+EXPORT_SYMBOL(config_group_find_item);
diff -ruNp a/fs/dlm/config.c b/fs/dlm/config.c
--- a/fs/dlm/config.c 2007-07-03 18:52:25.000000000 +0530
+++ b/fs/dlm/config.c 2007-07-03 19:43:57.000000000 +0530
@@ -752,7 +752,7 @@ static struct space *get_space(char *nam
return NULL;

mutex_lock(&space_list->cg_subsys->su_mtx);
- i = config_group_find_obj(space_list, name);
+ i = config_group_find_item(space_list, name);
mutex_unlock(&space_list->cg_subsys->su_mtx);

return to_space(i);
diff -ruNp a/include/linux/configfs.h b/include/linux/configfs.h
--- a/include/linux/configfs.h 2007-07-03 18:52:25.000000000 +0530
+++ b/include/linux/configfs.h 2007-07-03 19:46:56.000000000 +0530
@@ -85,12 +85,10 @@ struct config_item_type {
struct configfs_attribute **ct_attrs;
};

-
/**
* group - a group of config_items of a specific type, belonging
* to a specific subsystem.
*/
-
struct config_group {
struct config_item cg_item;
struct list_head cg_children;
@@ -98,13 +96,11 @@ struct config_group {
struct config_group **default_groups;
};

-
extern void config_group_init(struct config_group *group);
extern void config_group_init_type_name(struct config_group *group,
const char *name,
struct config_item_type *type);

-
static inline struct config_group *to_config_group(struct config_item *item)
{
return item ? container_of(item,struct config_group,cg_item) : NULL;
@@ -120,8 +116,8 @@ static inline void config_group_put(stru
config_item_put(&group->cg_item);
}

-extern struct config_item *config_group_find_obj(struct config_group *, const char *);
-
+extern struct config_item *config_group_find_item(struct config_group *,
+ const char *);

struct configfs_attribute {
const char *ca_name;
-
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