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

[Burakov, Anatoly]

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 at 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