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Commit 3fe6c5ce authored by Satyam Sharma's avatar Satyam Sharma Committed by Mark Fasheh
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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
  3168b078 manually resolved. --Mark ]

Signed-off-by: default avatarSatyam Sharma <ssatyam@cse.iitk.ac.in>
Cc: David Teigland <teigland@redhat.com>
Signed-off-by: default avatarJoel Becker <joel.becker@oracle.com>
Signed-off-by: default avatarMark Fasheh <mark.fasheh@oracle.com>
parent 9b1d9aa4

fs/configfs/item.c

+8 −10
Original line number Diff line number Diff line
@@ -183,23 +183,21 @@ void config_group_init(struct config_group *group) 
	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,

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) &&
@@ -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);

fs/dlm/config.c

+1 −1
Original line number Diff line number Diff line
@@ -752,7 +752,7 @@ static struct space *get_space(char *name) 
		return NULL;



	down(&space_list->cg_subsys->su_sem);

	i = config_group_find_obj(space_list, name);

	i = config_group_find_item(space_list, name);

	up(&space_list->cg_subsys->su_sem);



	return to_space(i);

include/linux/configfs.h

+2 −5
Original line number Diff line number Diff line
@@ -86,12 +86,10 @@ 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;
@@ -99,13 +97,11 @@ 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;
@@ -121,7 +117,8 @@ static inline void config_group_put(struct config_group *group) 
	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 {