Hi Guys,

Sorry for disturbing you. I have one small question regarding the min_mbuf_head/tailroom_req in rte_cryptodev_info.

I saw you were the people who discussed, reviewed and added that two fields.

IIUC, the two fields provided a hint to the PMD that HW can use(modify) the headroom and tailroom space to improve the performance.

But regarding the space(e.g. headroom) user reserved, should the data offset(sym_op->aead.data.offset) in struct rte_crypto_op also be taken into account?

e.g. if the mbuf in the operation is something like below:

|---headroom--|----op offset---|---payload to process---|---tailroom---|

In that case, what is the headroom mean to HW? Start from real mbuf headroom before op offset or the offset before payload?

Thanks,

Suanming Mou