Short answer: say Y.
+config TCP_ZERO_COPY_TRANSFER_COMPLETION_NOTIFICATION
+ bool "TCP/IP zero-copy transfer completion notification"
+ depends on INET
+ default SCST_ISCSI
+ ---help---
+ Adds support for sending a notification upon completion of a
+ zero-copy TCP/IP transfer. This can speed up certain TCP/IP
+ software. Currently this is only used by the iSCSI target driver
+ iSCSI-SCST.
+
+ If unsure, say N.
+
if INET
source "net/ipv4/Kconfig"
source "net/ipv6/Kconfig"