Re: [PATCH v4 06/35] net/ice: refactor context descriptor handling

Burakov, Anatoly
2026-02-10T12:42:30Z

On 2/9/2026 5:45 PM, Bruce Richardson wrote:
> Create a single function to manage all context descriptor handling,
> which returns either 0 or 1 depending on whether a descriptor is needed
> or not, as well as returning directly the descriptor contents if
> relevant.
>
> Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
> ---

<snip>

> +static __rte_always_inline uint16_t
> +get_context_desc(uint64_t ol_flags, const struct rte_mbuf *tx_pkt,
> + const union ci_tx_offload *tx_offload, const struct ci_tx_queue *txq,
> + uint64_t *qw0, uint64_t *qw1)
> +{
> + uint16_t cd_l2tag2 = 0;
> + uint64_t cd_type_cmd_tso_mss = ICE_TX_DESC_DTYPE_CTX;
> + uint32_t cd_tunneling_params = 0;
> + uint64_t ptp_tx_index = txq->ice_vsi->adapter->ptp_tx_index;
> +
> + if (ice_calc_context_desc(ol_flags) == 0)
> + return 0;
> +
> + if (ol_flags & RTE_MBUF_F_TX_TUNNEL_MASK)
> + ice_parse_tunneling_params(ol_flags, *tx_offload, &cd_tunneling_params);
> +
> + if (ol_flags & (RTE_MBUF_F_TX_TCP_SEG | RTE_MBUF_F_TX_UDP_SEG))
> + cd_type_cmd_tso_mss |= ice_set_tso_ctx(ol_flags, tx_pkt, *tx_offload);
> + else if (ol_flags & RTE_MBUF_F_TX_IEEE1588_TMST)
> + cd_type_cmd_tso_mss |=
> + ((uint64_t)CI_TX_CTX_DESC_TSYN << CI_TXD_QW1_CMD_S) |
> + ((ptp_tx_index << ICE_TXD_CTX_QW1_TSYN_S) & ICE_TXD_CTX_QW1_TSYN_M);

It's tangentially related to this commit but it caught my attention that
TSO and timestamping are mutually exclusive here. They *are* mutually
exclusive as far as the driver is concerned so that part is fine, but I
couldn't find any signs of us enforcing this limitation anywhere in our
configuration path, so a well behaved application could theoretically
arrive at this combination of mbuf flags without breaking anything.

(if I understand things correctly, this applies to both ice and i40e)

--
Thanks,
Anatoly