configfs: switch ->default groups to a linked list

Replace the current NULL-terminated array of default groups with a linked
list.  This gets rid of lots of nasty code to size and/or dynamically
allocate the array.

While we're at it also provide a conveniant helper to remove the default
groups.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Felipe Balbi <balbi@kernel.org>		[drivers/usb/gadget]
Acked-by: Joel Becker <jlbec@evilplan.org>
Acked-by: Nicholas Bellinger <nab@linux-iscsi.org>
Reviewed-by: Sagi Grimberg <sagig@mellanox.com>

2 files changed, 21 insertions, 24 deletions

diff --git a/fs/configfs/dir.c b/fs/configfs/dir.c
index f419519ec41f..b51ce6778145 100644
--- a/fs/configfs/dir.c
+++ b/fs/configfs/dir.c
@@ -701,23 +701,29 @@ static int populate_groups(struct config_group *group)
 {
         struct config_group *new_group;
         int ret = 0;
-        int i;
-
-        if (group->default_groups) {
-                for (i = 0; group->default_groups[i]; i++) {
-                        new_group = group->default_groups[i];
 
-                        ret = create_default_group(group, new_group);
-                        if (ret) {
-                                detach_groups(group);
-                                break;
-                        }
+        list_for_each_entry(new_group, &group->default_groups, group_entry) {
+                ret = create_default_group(group, new_group);
+                if (ret) {
+                        detach_groups(group);
+                        break;
                 }
         }
 
         return ret;
 }
 
+void configfs_remove_default_groups(struct config_group *group)
+{
+        struct config_group *g, *n;
+
+        list_for_each_entry_safe(g, n, &group->default_groups, group_entry) {
+                list_del(&g->group_entry);
+                config_item_put(&g->cg_item);
+        }
+}
+EXPORT_SYMBOL(configfs_remove_default_groups);
+
 /*
  * All of link_obj/unlink_obj/link_group/unlink_group require that
  * subsys->su_mutex is held.
@@ -766,15 +772,10 @@ static void link_obj(struct config_item *parent_item, struct config_item *item)
 
 static void unlink_group(struct config_group *group)
 {
-        int i;
         struct config_group *new_group;
 
-        if (group->default_groups) {
-                for (i = 0; group->default_groups[i]; i++) {
-                        new_group = group->default_groups[i];
-                        unlink_group(new_group);
-                }
-        }
+        list_for_each_entry(new_group, &group->default_groups, group_entry)
+                unlink_group(new_group);
 
         group->cg_subsys = NULL;
         unlink_obj(&group->cg_item);
@@ -782,7 +783,6 @@ static void unlink_group(struct config_group *group)
 
 static void link_group(struct config_group *parent_group, struct config_group *group)
 {
-        int i;
         struct config_group *new_group;
         struct configfs_subsystem *subsys = NULL; /* gcc is a turd */
 
@@ -796,12 +796,8 @@ static void link_group(struct config_group *parent_group, struct config_group *g
                 BUG();
         group->cg_subsys = subsys;
 
-        if (group->default_groups) {
-                for (i = 0; group->default_groups[i]; i++) {
-                        new_group = group->default_groups[i];
-                        link_group(group, new_group);
-                }
-        }
+        list_for_each_entry(new_group, &group->default_groups, group_entry)
+                link_group(group, new_group);
 }
 
 /*
diff --git a/fs/configfs/item.c b/fs/configfs/item.c
index b863a09cd2f1..8b2a994042dd 100644
--- a/fs/configfs/item.c
+++ b/fs/configfs/item.c
@@ -182,6 +182,7 @@ void config_group_init(struct config_group *group)
 {
         config_item_init(&group->cg_item);
         INIT_LIST_HEAD(&group->cg_children);
+        INIT_LIST_HEAD(&group->default_groups);
 }
 EXPORT_SYMBOL(config_group_init);