Re: [PATCH] net/idpf: handle Tx of mbuf segments larger than 16k

["Burakov, Anatoly" <anatoly.burakov@intel.com>]

> CodeRabbit picked up on something here, and I think it's worth 
> highlighting.
> 
> When we're splitting segments, we assign txe->mbuf to the first segment...
> 
> <snip>
> 
>> +                txe = &sw_ring[sw_id];
>> +                /* sub-descriptor slots do not own the mbuf */
>> +                txe->mbuf = NULL;
> 
> ...then set subsequent segments to NULL...
> 
>> +            }
>> -            /* Setup TX descriptor */
>> -            txd->buf_addr =
>> -                rte_cpu_to_le_64(rte_mbuf_data_iova(tx_pkt));
>> -            cmd_dtype |= IDPF_TX_DESC_DTYPE_FLEX_FLOW_SCHE;
>> +            /* Write the final (or only) descriptor for this segment */
>> +            txd = &txr[tx_id];
>> +            txd->buf_addr = rte_cpu_to_le_64(buf_dma_addr);
>>               txd->qw1.cmd_dtype = cmd_dtype;
>> -            txd->qw1.rxr_bufsize = tx_pkt->data_len;
>> +            txd->qw1.rxr_bufsize = slen;
>>               txd->qw1.compl_tag = sw_id;
> 
> ...and we're supposed to write the final descriptor here, but we've 
> stored the mbuf pointer in the *first* descriptor, not in the *last* 
> one, which means when this descriptor gets to processing completions, 
> the mbuf pointer of that descriptor will be NULL? Is that intended?

Actually, digging in, I don't see where we free mbufs at all in splitq 
path? Am I missing something here?

-- 
Thanks,
Anatoly