+For inline protocol offloaded ingress traffic, the application can register a
+pointer, ``userdata`` , in the security session. When the packet is received,
+``rte_security_get_userdata()`` would return the userdata registered for the
+security session which processed the packet.
+
+.. note::
+
+ In case of inline processed packets, ``rte_mbuf.udata64`` field would be
+ used by the driver to relay information on the security processing
+ associated with the packet. In ingress, the driver would set this in Rx
+ path while in egress, ``rte_security_set_pkt_metadata()`` would perform a
+ similar operation. The application is expected not to modify the field
+ when it has relevant info. For ingress, this device-specific 64 bit value
+ is required to derive other information (like userdata), required for
+ identifying the security processing done on the packet.
+