fsnotify: create helpers to get sb and connp from object

In preparation to passing an object pointer to add/remove/find mark
helpers, create helpers to get sb and connp by object type.
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Message-Id: <20240317184154.1200192-3-amir73il@gmail.com>

fs/notify/fsnotify.h

@@ -27,6 +27,21 @@ static inline struct super_block *fsnotify_conn_sb(
 	return container_of(conn->obj, struct super_block, s_fsnotify_marks);
 }
 
+static inline struct super_block *fsnotify_object_sb(void *obj,
+			enum fsnotify_obj_type obj_type)
+{
+	switch (obj_type) {
+	case FSNOTIFY_OBJ_TYPE_INODE:
+		return ((struct inode *)obj)->i_sb;
+	case FSNOTIFY_OBJ_TYPE_VFSMOUNT:
+		return ((struct vfsmount *)obj)->mnt_sb;
+	case FSNOTIFY_OBJ_TYPE_SB:
+		return (struct super_block *)obj;
+	default:
+		return NULL;
+	}
+}
+
 static inline struct super_block *fsnotify_connector_sb(
 				struct fsnotify_mark_connector *conn)
 {

fs/notify/mark.c

@@ -97,6 +97,21 @@ void fsnotify_get_mark(struct fsnotify_mark *mark)
 	refcount_inc(&mark->refcnt);
 }
 
+static fsnotify_connp_t *fsnotify_object_connp(void *obj,
+				enum fsnotify_obj_type obj_type)
+{
+	switch (obj_type) {
+	case FSNOTIFY_OBJ_TYPE_INODE:
+		return &((struct inode *)obj)->i_fsnotify_marks;
+	case FSNOTIFY_OBJ_TYPE_VFSMOUNT:
+		return &real_mount(obj)->mnt_fsnotify_marks;
+	case FSNOTIFY_OBJ_TYPE_SB:
+		return &((struct super_block *)obj)->s_fsnotify_marks;
+	default:
+		return NULL;
+	}
+}
+
 static __u32 *fsnotify_conn_mask_p(struct fsnotify_mark_connector *conn)
 {
 	if (conn->type == FSNOTIFY_OBJ_TYPE_INODE)