> -----Original Message-----
> From: Thomas Monjalon <tho...@monjalon.net>
> Sent: Thursday, November 25, 2021 15:07
> To: Andrew Rybchenko <andrew.rybche...@oktetlabs.ru>; Ajit Khaparde
> <ajit.khapa...@broadcom.com>; Somnath Kotur
> <somnath.ko...@broadcom.com>; Rahul Lakkireddy
> <rahul.lakkire...@chelsio.com>; Slava Ovsiienko <viachesl...@nvidia.com>;
> Ferruh Yigit <ferruh.yi...@intel.com>
> Cc: dev@dpdk.org; Ori Kam <or...@nvidia.com>
> Subject: Re: [PATCH v3] ethdev: deprecate header fields and metadata flow
> actions
>
> 25/11/2021 12:53, Ferruh Yigit:
> > On 11/24/2021 3:37 PM, Viacheslav Ovsiienko wrote:
> > > The generic RTE_FLOW_ACTION_TYPE_MODIFY_FIELD action was
> introduced
> > > by [1]. This action provides an unified way to perform various
> > > arithmetic and transfer operations over packet network header fields
> > > and packet metadata.
> > >
> > > [1] commit 641dbe4fb053 ("net/mlx5: support modify field flow
> > > action")
> > >
> > > On other side there are a bunch of multiple legacy actions, that can
> > > be superseded by the generic modify field action:
> > >
> > > RTE_FLOW_ACTION_TYPE_OF_SET_MPLS_TTL
> > > RTE_FLOW_ACTION_TYPE_OF_DEC_MPLS_TTL
> > > RTE_FLOW_ACTION_TYPE_OF_SET_NW_TTL
> > > RTE_FLOW_ACTION_TYPE_OF_DEC_NW_TTL sfc
> > > RTE_FLOW_ACTION_TYPE_OF_COPY_TTL_OUT
> > > RTE_FLOW_ACTION_TYPE_OF_COPY_TTL_IN
> > > RTE_FLOW_ACTION_TYPE_SET_IPV4_SRC bnxt, cxgbe, mlx5
> > > RTE_FLOW_ACTION_TYPE_SET_IPV4_DST bnxt, cxgbe, mlx5
> > > RTE_FLOW_ACTION_TYPE_SET_IPV6_SRC cxgbe, mlx5
> > > RTE_FLOW_ACTION_TYPE_SET_IPV6_DST cxgbe, mlx5
> > > RTE_FLOW_ACTION_TYPE_SET_TP_SRC cxgbe, mlx5
> > > RTE_FLOW_ACTION_TYPE_SET_TP_DST cxgbe, mlx5
> > > RTE_FLOW_ACTION_TYPE_DEC_TTL mlx5, sfc
> > > RTE_FLOW_ACTION_TYPE_SET_TTL mlx5
> > > RTE_FLOW_ACTION_TYPE_SET_MAC_SRC cxgbe, mlx5
> > > RTE_FLOW_ACTION_TYPE_SET_MAC_DST cxgbe, mlx5
> > > RTE_FLOW_ACTION_TYPE_INC_TCP_SEQ mlx5
> > > RTE_FLOW_ACTION_TYPE_DEC_TCP_SEQ mlx5
> > > RTE_FLOW_ACTION_TYPE_INC_TCP_ACK mlx5
> > > RTE_FLOW_ACTION_TYPE_DEC_TCP_ACK mlx5
> > > RTE_FLOW_ACTION_TYPE_SET_IPV4_DSCP mlx5
> > > RTE_FLOW_ACTION_TYPE_SET_IPV6_DSCP mlx5
> > > RTE_FLOW_ACTION_TYPE_OF_SET_VLAN_VID bnxt, cnxk, cxgbe, enic,
> > > mlx5, octeontx2, sfc
> > > RTE_FLOW_ACTION_TYPE_OF_SET_VLAN_PCP bnxt, cnxk, cxgbe, enic,
> > > mlx5, octeontx2, sfc
> > > RTE_FLOW_ACTION_TYPE_SET_TAG mlx5
> > > RTE_FLOW_ACTION_TYPE_SET_META mlx5
> > >
> > > This note deprecates the following RTE Flow actions:
> > > 1. As not supported by any of PMDs:
> > >
> > > RTE_FLOW_ACTION_TYPE_OF_SET_MPLS_TTL
> > > RTE_FLOW_ACTION_TYPE_OF_DEC_MPLS_TTL
> > > RTE_FLOW_ACTION_TYPE_OF_SET_NW_TTL
> > > RTE_FLOW_ACTION_TYPE_OF_COPY_TTL_OUT
> > > RTE_FLOW_ACTION_TYPE_OF_COPY_TTL_IN
> > >
> > > 2. As supposed to be replaced by generig field modify action:
> > > RTE_FLOW_ACTION_TYPE_OF_DEC_NW_TTL
> > > RTE_FLOW_ACTION_TYPE_SET_IPV4_SRC
> > > RTE_FLOW_ACTION_TYPE_SET_IPV4_DST
> > > RTE_FLOW_ACTION_TYPE_SET_IPV6_SRC
> > > RTE_FLOW_ACTION_TYPE_SET_IPV6_DST
> > > RTE_FLOW_ACTION_TYPE_SET_TP_SRC
> > > RTE_FLOW_ACTION_TYPE_SET_TP_DST
> > > RTE_FLOW_ACTION_TYPE_DEC_TTL
> > > RTE_FLOW_ACTION_TYPE_SET_TTL
> > > RTE_FLOW_ACTION_TYPE_SET_MAC_SRC
> > > RTE_FLOW_ACTION_TYPE_SET_MAC_DST
> > > RTE_FLOW_ACTION_TYPE_INC_TCP_SEQ
> > > RTE_FLOW_ACTION_TYPE_DEC_TCP_SEQ
> > > RTE_FLOW_ACTION_TYPE_INC_TCP_ACK
> > > RTE_FLOW_ACTION_TYPE_DEC_TCP_ACK
> > > RTE_FLOW_ACTION_TYPE_SET_IPV4_DSCP
> > > RTE_FLOW_ACTION_TYPE_SET_IPV6_DSCP
> > > RTE_FLOW_ACTION_TYPE_SET_TAG
> > > RTE_FLOW_ACTION_TYPE_SET_META
> > >
> > > The VLAN set actions are interrelated to VLAN header
> > > insertion/removal and supported by multiple PMDs and supposed to be
> > > just deprecated but not be removed in 22.11.
> > >
> >
> > Why not remove them for v22.11? Do you think PMDs can't change the
> > existing implementation until 22.11?
> >
> > > Signed-off-by: Viacheslav Ovsiienko <viachesl...@nvidia.com>
> > >
> > > --
> > > v2 - deprecation.rst is updated
> > > v3 - doc comments addressed
> > > - commit message comments addressed
> > > - SET_VLAN_VID and SET_VLAN_PCP actions deprecated, but will not
> > > be removed in 22.11
> >
> > Deprecated symbols are to prevent new code using them, but for this
> > case there is no alternative, since PMDs still don't support
> > 'RTE_FLOW_ACTION_TYPE_MODIFY_FIELD' yet.
>
> This patch is not preventing new code using old actions, there are just
> comments to point to the new direction.
>
> > This patch is forcing users to use deprecated actions (except from mlx).
>
> I don't get it.
> It is encouraging to use the new generic action, which is supported only by
> mlx5 for now.
>
>
> > What about a slight change:
> > 1- In this release, update header/document as
> 'RTE_FLOW_ACTION_TYPE_MODIFY_FIELD'
> > is preferred way if supported. Instead of deprecating old ones.
>
> Deprecation is just a comment, clearly showing that it may be removed in
> future.
> In my opinion, it makes the message simple and clear.
>
>
> > 2- Have an agreement with PMD maintainers to switch to new action before
> v22.11,
> > and don't accept old action implementation in PMDs anymore.
> > Based on agreement update 'deprecation.rst' in this release to note that
> > old actions will be removed on v22.11.
> > (It would be good to have a check to prevent old actions merged
> > during that time.)
>
> Not sure I get it.
> You want to remove VLAN actions? I think it is premature.
>
> > 3- In v22.11, remove old actions, the PMDs that don't support
> MODIFY_FIELD
> > action will lose the feature.
>
> The VLAN actions are probably already used a lot in the field.
> I would consider removing them only if it becomes a burden to maintain.
+1
Dropping VLAN might trigger an avalanche of changes in applications - it is
supported by multiple PMDs and should be widely engaged.
Other legacy actions are supported by very limited set of drivers and usage
area should be smaller, I would say risk is moderate.
With best regards,
Slava
