[PATCH] doc: announce ethdev operation struct changes

[Morten Brørup]

> From: Thomas Monjalon [mailto:thomas at monjalon.net]
> Sent: Friday, 28 July 2023 16.57
> 
> 04/07/2023 10:10, Feifei Wang:
> > To support mbufs recycle mode, announce the coming ABI changes
> > from DPDK 23.11.
> >
> > Signed-off-by: Feifei Wang <feifei.wang2 at arm.com>
> > Reviewed-by: Ruifeng Wang <ruifeng.wang at arm.com>
> > ---
> >  doc/guides/rel_notes/deprecation.rst | 4 ++++
> >  1 file changed, 4 insertions(+)
> >
> > diff --git a/doc/guides/rel_notes/deprecation.rst
> b/doc/guides/rel_notes/deprecation.rst
> > index 66431789b0..c7e1ffafb2 100644
> > --- a/doc/guides/rel_notes/deprecation.rst
> > +++ b/doc/guides/rel_notes/deprecation.rst
> > @@ -118,6 +118,10 @@ Deprecation Notices
> >    The legacy actions should be removed
> >    once ``MODIFY_FIELD`` alternative is implemented in drivers.
> >
> > +* ethdev: The Ethernet device data structure ``struct rte_eth_dev`` and
> > +  the fast-path ethdev flat array ``struct rte_eth_fp_ops`` will be updated
> > +  with new fields to support mbufs recycle mode from DPDK 23.11.

Existing fields will also be moved around [1]:

@@ -83,15 +90,17 @@  struct rte_eth_fp_ops {
 	 * Rx fast-path functions and related data.
 	 * 64-bit systems: occupies first 64B line
 	 */
+	/** Rx queues data. */
+	struct rte_ethdev_qdata rxq;
 	/** PMD receive function. */
 	eth_rx_burst_t rx_pkt_burst;
 	/** Get the number of used Rx descriptors. */
 	eth_rx_queue_count_t rx_queue_count;
 	/** Check the status of a Rx descriptor. */
 	eth_rx_descriptor_status_t rx_descriptor_status;
-	/** Rx queues data. */
-	struct rte_ethdev_qdata rxq;
-	uintptr_t reserved1[3];
+	/** Refill Rx descriptors with the recycling mbufs. */
+	eth_recycle_rx_descriptors_refill_t recycle_rx_descriptors_refill;
+	uintptr_t reserved1[2];
 	/**@}*/
 
 	/**@{*/
@@ -99,15 +108,17 @@  struct rte_eth_fp_ops {
 	 * Tx fast-path functions and related data.
 	 * 64-bit systems: occupies second 64B line
 	 */
+	/** Tx queues data. */
+	struct rte_ethdev_qdata txq;
 	/** PMD transmit function. */
 	eth_tx_burst_t tx_pkt_burst;
 	/** PMD transmit prepare function. */
 	eth_tx_prep_t tx_pkt_prepare;
 	/** Check the status of a Tx descriptor. */
 	eth_tx_descriptor_status_t tx_descriptor_status;
-	/** Tx queues data. */
-	struct rte_ethdev_qdata txq;
-	uintptr_t reserved2[3];
+	/** Copy used mbufs from Tx mbuf ring into Rx. */
+	eth_recycle_tx_mbufs_reuse_t recycle_tx_mbufs_reuse;
+	uintptr_t reserved2[2];
 	/**@}*/

[1]: https://patchwork.dpdk.org/project/dpdk/patch/20230706095004.1848199-2-feifei.wang2@arm.com/

> 
> It does seem to be an impacting change for existing applications,
> except that it is allowed only during ABI breakage window.
> 
> I think my patch should be enough:
> https://patches.dpdk.org/project/dpdk/patch/20230728142946.1201459-1-
> thomas at monjalon.net/
>