06/08/2019 20:17, Andrew Rybchenko:

On 8/6/19 5:56 PM, Matan Azrad wrote:

quoted

The API breakage is because the ``tso_segsz`` field was documented for
LRO.

The ``tso_segsz`` field in mbuf indicates the size of each segment in
the LRO packet in Rx path and should be provided by the LRO packet
port.

While the generic LRO packet may aggregate different segments sizes in
one packet, it is impossible to expose this information for each segment
by one field and it doesn't make sense to expose all the segments sizes
in the mbuf.

A new field may be added as union with the above field to expose the
number of segments aggregated in the LRO packet.

Signed-off-by: Matan Azrad <redacted>
---

--- a/doc/guides/rel_notes/deprecation.rst
+++ b/doc/guides/rel_notes/deprecation.rst
+* mbuf: Remove ``tso_segsz`` mbuf field providing for LRO support. Use union
+  block for the field memory to be shared with a new field ``lro_segs_n``
+  indicates the number of segments aggregated in the LRO packet.

I think that the number of segments is more logical in the case of LRO.
The question (already asked by Konstantin) is why it is needed at all
(statistics?). If so, it still makes sense.

Segment size is misleading here, since not all segments
could be the same size. So,

Acked-by: Andrew Rybchenko <redacted>

As far as I can see bnxt and qede do not fill it in.
mlx5 and vmxnet3 have the number of segments (vmxnet3 has segment
size sometimes and sometimes use a function to guess the value).
So both will win from the change.
It looks like virtio does not have number of segments. CC Maxime to
comment.

I support improving the API for LRO.
Unfortunately, the consensus is not strong enough at the moment.
Anyway we should avoid any API breakage in 19.11,
so I suggest to do only non-breaking additions in 19.11 if possible:
	- fill a new unioned field for LRO segments number
	- not set PKT_RX_LRO (which is still related to tso_segsz)