Re: [PATCH net-next V2 09/13] net/mlx5e: psp: Add an rx_decap steering table

On Tue, 2026-08-04 at 13:19 -0400, Daniel Zahka wrote:

On 8/4/26 4:35 AM, Tariq Toukan wrote:

quoted

From: Cosmin Ratiu <redacted>

Introduce an additional steering table for PSP transport mode
decapsulation, containing:
- one rule per supported PSP version which does:
   - transport mode decap (removes UDP+PSP headers and PSP trailer)
     - recomputes iph->tot_len
     - recomputes IP checksum
     - reparses packet headers
   - copy SPI into reg_b (which ends up as cqe.ft_metadata)
   - set a decap marker and the PSP version in the flow_tag, so the
RX
     handler can make sense of the packet
- default drop rule for unsupported PSP versions (per PSP spec).

Packets are forwarded to the previously added rx table, where:
- one rule forwards UDP traffic to the UDP default destination.
- default rule forwards traffic to the TTC table.

The reason is to avoid steering loops. If packets were to be
injected
into the TTC directly after rx_decap, it may be possible to create
a
steering loop with RX packets of the form IP|UDP|PSP|UDP|PSP...
The rx flow table guarantees that packets go through PSP steering
at
most once.

The steering mode is saved in a new field 'fs.decap_enabled'.
Updating the mode is done through accel_psp_fs_rx_reconfigure(),
which
creates the decap steering table if needed and possible. It then
uses an
atomic rule update to redirect traffic to the new table.
This is now invoked with decap_wanted == false.
The intention is for failures creating the new table to not block
feature
reconfig. A message is logged when table creation failed and PSP
for HW
GRO will not work in that case.
Nothing happens on HW without the ability to decapsulate PSP
transport.

An upcoming patch will add dynamic reconfiguration of PSP steering
based
on HW GRO.

Signed-off-by: Cosmin Ratiu <redacted>
Reviewed-by: Dragos Tatulea <dtatulea@nvidia.com>
Signed-off-by: Tariq Toukan <tariqt@nvidia.com>

Cosmin, can you TAL at 
https://lore.kernel.org/all/0d72c5b2-6d4c-40d4-8cbe-8cd95d61a230@gmail.com/ (local)
 
and let me know if this is an issue or not? I see the patch looks the
same, but wasn't sure if you didn't see my message or if it is a
false 
positive.

Apologies for this, I was on vacation and couldn't reply. And I think I
misled Tariq into thinking this wasn't a real issue, so he posted the
series again (Apologies, Tariq). As noted in V1, this will be addressed
in V3.

Cosmin.