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	[PATCH] configfs+dlm: Rename config_group_find_obj and state semantics clearly
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. --Joel ]
[ Conflict in fs/dlm/config.c with commit
  3168b0780d manually resolved. --Mark ]
Signed-off-by: Satyam Sharma <ssatyam@cse.iitk.ac.in>
Cc: David Teigland <teigland@redhat.com>
Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
			
			
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					 3 changed files with 11 additions and 16 deletions
				
			
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					@ -183,23 +183,21 @@ void config_group_init(struct config_group *group)
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	INIT_LIST_HEAD(&group->cg_children);
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						INIT_LIST_HEAD(&group->cg_children);
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}
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					}
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/**
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					/**
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 *	config_group_find_obj - search for item in group.
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					 *	config_group_find_item - search for item in group.
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 *	@group:	group we're looking in.
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					 *	@group:	group we're looking in.
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 *	@name:	item's name.
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					 *	@name:	item's name.
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 *
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					 *
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 *	Lock group via @group->cg_subsys, and iterate over @group->cg_list,
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					 *	Iterate over @group->cg_list, looking for a matching config_item.
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 *	looking for a matching config_item. If matching item is found
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					 *	If matching item is found take a reference and return the item.
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 *	take a reference and return the item.
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					 *	Caller must have locked group via @group->cg_subsys->su_mtx.
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 */
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					 */
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struct config_item *config_group_find_obj(struct config_group *group,
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					struct config_item *config_group_find_item(struct config_group *group,
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					   const char *name)
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										   const char *name)
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{
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					{
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	struct list_head * entry;
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						struct list_head * entry;
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	struct config_item * ret = NULL;
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						struct config_item * ret = NULL;
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        /* XXX LOCKING! */
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	list_for_each(entry,&group->cg_children) {
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						list_for_each(entry,&group->cg_children) {
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		struct config_item * item = to_item(entry);
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							struct config_item * item = to_item(entry);
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		if (config_item_name(item) &&
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							if (config_item_name(item) &&
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					@ -215,4 +213,4 @@ EXPORT_SYMBOL(config_item_init);
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EXPORT_SYMBOL(config_group_init);
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					EXPORT_SYMBOL(config_group_init);
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EXPORT_SYMBOL(config_item_get);
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					EXPORT_SYMBOL(config_item_get);
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EXPORT_SYMBOL(config_item_put);
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					EXPORT_SYMBOL(config_item_put);
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EXPORT_SYMBOL(config_group_find_obj);
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					EXPORT_SYMBOL(config_group_find_item);
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					@ -752,7 +752,7 @@ static struct space *get_space(char *name)
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		return NULL;
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							return NULL;
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	down(&space_list->cg_subsys->su_sem);
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						down(&space_list->cg_subsys->su_sem);
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	i = config_group_find_obj(space_list, name);
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						i = config_group_find_item(space_list, name);
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	up(&space_list->cg_subsys->su_sem);
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						up(&space_list->cg_subsys->su_sem);
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	return to_space(i);
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						return to_space(i);
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					@ -86,12 +86,10 @@ struct config_item_type {
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	struct configfs_attribute		**ct_attrs;
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						struct configfs_attribute		**ct_attrs;
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};
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					};
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/**
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					/**
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 *	group - a group of config_items of a specific type, belonging
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					 *	group - a group of config_items of a specific type, belonging
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 *	to a specific subsystem.
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					 *	to a specific subsystem.
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 */
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					 */
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struct config_group {
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					struct config_group {
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	struct config_item		cg_item;
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						struct config_item		cg_item;
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	struct list_head		cg_children;
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						struct list_head		cg_children;
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					@ -99,13 +97,11 @@ struct config_group {
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	struct config_group		**default_groups;
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						struct config_group		**default_groups;
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};
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					};
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extern void config_group_init(struct config_group *group);
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					extern void config_group_init(struct config_group *group);
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extern void config_group_init_type_name(struct config_group *group,
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					extern void config_group_init_type_name(struct config_group *group,
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					const char *name,
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										const char *name,
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					struct config_item_type *type);
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										struct config_item_type *type);
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static inline struct config_group *to_config_group(struct config_item *item)
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					static inline struct config_group *to_config_group(struct config_item *item)
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{
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					{
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	return item ? container_of(item,struct config_group,cg_item) : NULL;
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						return item ? container_of(item,struct config_group,cg_item) : NULL;
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					@ -121,7 +117,8 @@ static inline void config_group_put(struct config_group *group)
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	config_item_put(&group->cg_item);
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						config_item_put(&group->cg_item);
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}
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					}
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extern struct config_item *config_group_find_obj(struct config_group *, const char *);
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					extern struct config_item *config_group_find_item(struct config_group *,
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											  const char *);
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struct configfs_attribute {
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					struct configfs_attribute {
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