Re: [PATCH v2] mptcp: do not drop partial packets

[Paolo Abeni <pabeni@redhat.com>]

On 4/22/26 4:39 PM, Shardul Bankar wrote:
> When a packet arrives with map_seq < ack_seq < end_seq, the beginning
> of the packet has already been acknowledged but the end contains new
> data.  Currently the entire packet is dropped as "old data," forcing
> the sender to retransmit.
> 
> Instead, skip the already-acked bytes by adjusting the skb offset and
> enqueue only the new portion.  Update bytes_received and ack_seq to
> reflect the new data consumed.
> 
> A previous attempt at this fix (commit 1d2ce718811a ("mptcp: do not
> drop partial packets"), reverted in commit bf39160c4218 ("Revert
> "mptcp: do not drop partial packets"")) also added a zero-window
> check and changed rcv_wnd_sent initialization, which caused test
> regressions.  This version addresses only the partial packet handling
> without modifying receive window accounting.
> 
> Fixes: ab174ad8ef76 ("mptcp: move ooo skbs into msk out of order queue.")
> Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/600
> Signed-off-by: Shardul Bankar <shardul.b@mpiricsoftware.com>

It would be great if you could send a v3 addressing the AI comment.

If you don't have time or capacity, please LMK, I can send v3 with your
SoB and the needed editing.

Thanks,

Paolo