Query on new ethtool RSS hashing options

Hi,

We have a requirement where in we want RSS hashing to be done on packet fields
which are not currently supported by the ethtool.

Current options:
ehtool -n <dev> rx-flow-hash
tcp4|udp4|ah4|esp4|sctp4|tcp6|udp6|ah6|esp6|sctp6 m|v|t|s|d|f|n|r

Specifically our requirement is to calculate hash with DSA tag (which
is inserted by switch) plus the TCP/UDP 4-tuple as input.

Is it okay to add such options to the ethtool ?
or will it be better to add a generic option to take pkt data offset
and number of bytes ?

Something like
ethtool -n <dev> rx-flow-hash tcp4 sdfn off <offset in the pkt> num
<number of bytes/bits>

Any comments, please.

Thanks,
Sunil.