# Re: \[PATCH v5 net-next 01/36\] net: Introduce direct data placement tcp offload

- From: Boris Pismenny \<hidden\>
- Date: 2021-07-22 14:03:26 
- List: netdev
- Page: https://ratatoskr.run/netdev/2021/07/6570968
- Thread: https://ratatoskr.run/linux-nvme/2021/07/6570924/t.md

```text
On 22/07/2021 16:39, Eric Dumazet wrote:
> On Thu, Jul 22, 2021 at 3:33 PM Boris Pismenny [ref] wrote:
> 
>> Sorry. My response above was about skb_condense which I've confused with
>> tcp_collapse.
>>
>> In tcp_collapse, we could allow the copy, but the problem is CRC, which
>> like TLS's skb->decrypted marks that the data passed the digest
>> validation in the NIC. If we allow collapsing SKBs with mixed marks, we
>> will need to force software copy+crc verification. As TCP collapse is
>> indeed rare and the offload is opportunistic in nature, we can make this
>> change and submit another version, but I'm confused; why was it OK for
>> TLS, while it is not OK for DDP+CRC?
>>
> 
> Ah.... I guess I was focused on the DDP part, while all your changes
> are really about the CRC part.
> 
> Perhaps having an accessor to express the CRC status (and not be
> confused by the DDP part)
>  could help the intent of the code.
> 

An accessor function sounds like a great idea for readability, thanks Eric!

We will re-spin the series and add it to v6.
```