fs/notify/inotify: decrement user inotify count on close

The per-user inotify_devs value is incremented each time a new file is
allocated, but never decremented. This led to inotify_init failing after a
limited number of calls.

Signed-off-by: Keith Packard <[e-mail]>
Signed-off-by: Eric Paris <[e-mail]>

fs/notify/inotify/inotify_user.c

···
 static int inotify_release(struct inode *ignored, struct file *file)
 {
 	struct fsnotify_group *group = file->private_data;
+	struct user_struct *user = group->inotify_data.user;
 
 	fsnotify_clear_marks_by_group(group);
 
 	/* free this group, matching get was inotify_init->fsnotify_obtain_group */
 	fsnotify_put_group(group);
+
+	atomic_dec(&user->inotify_devs);
 
 	return 0;
 }