ethdev: hide internal structures

[Tyler Retzlaff]

hi folks,

I don't understand the text of this change.  would you mind explaining?

    commit f9bdee267ab84fd12dc288419aba341310b6ae08
    Author: Konstantin Ananyev <konstantin.ananyev at intel.com>
    Date:   Wed Oct 13 14:37:04 2021 +0100
    ethdev: hide internal structures                        

+* ethdev: Made ``rte_eth_dev``, ``rte_eth_dev_data``, ``rte_eth_rxtx_callback``           +  private data structures.  ``rte_eth_devices[]`` can't be accessed directly
+  by user any more. While it is an ABI breakage, this change is intended
+  to be transparent for both users (no changes in user app is required) and               +  PMD developers (no changes in PMD is required).


if it is an ABI break (and it is also an API break) how is it that
this change could be "transparent" to the user application?

* existing binaries will not run. (they need to be recompiled)
* existing code will not compile. (code changes are required)

in order to cope with this change an application will have to have the
code modified and will need to be re-compiled. so i don't understand how
that is transparent?

thanks