fsnotify: remove group_num altogether

The original fsnotify interface has a group-num which was intended to be
able to find a group after it was added.  I no longer think this is a
necessary thing to do and so we remove the group_num.

Signed-off-by: Eric Paris <eparis@redhat.com>

3 files changed, 4 insertions, 58 deletions

diff --git a/fs/notify/dnotify/dnotify.c b/fs/notify/dnotify/dnotify.c
index a213b83a59c..1f46aeac338 100644
--- a/fs/notify/dnotify/dnotify.c
+++ b/fs/notify/dnotify/dnotify.c
@@ -433,8 +433,7 @@ static int __init dnotify_init(void)
 	dnotify_struct_cache = KMEM_CACHE(dnotify_struct, SLAB_PANIC);
 	dnotify_mark_entry_cache = KMEM_CACHE(dnotify_mark_entry, SLAB_PANIC);
 
-	dnotify_group = fsnotify_obtain_group(DNOTIFY_GROUP_NUM,
-					      0, &dnotify_fsnotify_ops);
+	dnotify_group = fsnotify_obtain_group(0, &dnotify_fsnotify_ops);
 	if (IS_ERR(dnotify_group))
 		panic("unable to allocate fsnotify group for dnotify\n");
 	return 0;
diff --git a/fs/notify/group.c b/fs/notify/group.c
index 777ca821225..62fb8961a57 100644
--- a/fs/notify/group.c
+++ b/fs/notify/group.c
@@ -78,15 +78,6 @@ void fsnotify_recalc_group_mask(struct fsnotify_group *group)
 }
 
 /*
- * Take a reference to a group so things found under the fsnotify_grp_mutex
- * can't get freed under us
- */
-static void fsnotify_get_group(struct fsnotify_group *group)
-{
-	atomic_inc(&group->refcnt);
-}
-
-/*
  * Final freeing of a group
  */
 void fsnotify_final_destroy_group(struct fsnotify_group *group)
@@ -171,40 +162,14 @@ void fsnotify_put_group(struct fsnotify_group *group)
 }
 
 /*
- * Simply run the fsnotify_groups list and find a group which matches
- * the given parameters.  If a group is found we take a reference to that
- * group.
- */
-static struct fsnotify_group *fsnotify_find_group(unsigned int group_num, __u32 mask,
-						  const struct fsnotify_ops *ops)
-{
-	struct fsnotify_group *group_iter;
-	struct fsnotify_group *group = NULL;
-
-	BUG_ON(!mutex_is_locked(&fsnotify_grp_mutex));
-
-	list_for_each_entry_rcu(group_iter, &fsnotify_groups, group_list) {
-		if (group_iter->group_num == group_num) {
-			if ((group_iter->mask == mask) &&
-			    (group_iter->ops == ops)) {
-				fsnotify_get_group(group_iter);
-				group = group_iter;
-			} else
-				group = ERR_PTR(-EEXIST);
-		}
-	}
-	return group;
-}
-
-/*
  * Either finds an existing group which matches the group_num, mask, and ops or
  * creates a new group and adds it to the global group list.  In either case we
  * take a reference for the group returned.
  */
-struct fsnotify_group *fsnotify_obtain_group(unsigned int group_num, __u32 mask,
+struct fsnotify_group *fsnotify_obtain_group(__u32 mask,
 					     const struct fsnotify_ops *ops)
 {
-	struct fsnotify_group *group, *tgroup;
+	struct fsnotify_group *group;
 
 	/* very low use, simpler locking if we just always alloc */
 	group = kzalloc(sizeof(struct fsnotify_group), GFP_KERNEL);
@@ -214,7 +179,6 @@ struct fsnotify_group *fsnotify_obtain_group(unsigned int group_num, __u32 mask,
 	atomic_set(&group->refcnt, 1);
 
 	group->on_group_list = 0;
-	group->group_num = group_num;
 	group->mask = mask;
 
 	mutex_init(&group->notification_mutex);
@@ -230,14 +194,6 @@ struct fsnotify_group *fsnotify_obtain_group(unsigned int group_num, __u32 mask,
 	group->ops = ops;
 
 	mutex_lock(&fsnotify_grp_mutex);
-	tgroup = fsnotify_find_group(group_num, mask, ops);
-	if (tgroup) {
-		/* group already exists */
-		mutex_unlock(&fsnotify_grp_mutex);
-		/* destroy the new one we made */
-		fsnotify_put_group(group);
-		return tgroup;
-	}
 
 	/* group not found, add a new one */
 	list_add_rcu(&group->group_list, &fsnotify_groups);
diff --git a/fs/notify/inotify/inotify_user.c b/fs/notify/inotify/inotify_user.c
index cbe16df326f..cae317f5bd9 100644
--- a/fs/notify/inotify/inotify_user.c
+++ b/fs/notify/inotify/inotify_user.c
@@ -51,12 +51,6 @@ int inotify_max_user_watches __read_mostly;
 static struct kmem_cache *inotify_inode_mark_cachep __read_mostly;
 struct kmem_cache *event_priv_cachep __read_mostly;
 
-/*
- * When inotify registers a new group it increments this and uses that
- * value as an offset to set the fsnotify group "name" and priority.
- */
-static atomic_t inotify_grp_num;
-
 #ifdef CONFIG_SYSCTL
 
 #include <linux/sysctl.h>
@@ -700,11 +694,8 @@ retry:
 static struct fsnotify_group *inotify_new_group(struct user_struct *user, unsigned int max_events)
 {
 	struct fsnotify_group *group;
-	unsigned int grp_num;
 
-	/* fsnotify_obtain_group took a reference to group, we put this when we kill the file in the end */
-	grp_num = (INOTIFY_GROUP_NUM - atomic_inc_return(&inotify_grp_num));
-	group = fsnotify_obtain_group(grp_num, 0, &inotify_fsnotify_ops);
+	group = fsnotify_obtain_group(0, &inotify_fsnotify_ops);
 	if (IS_ERR(group))
 		return group;