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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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