On 2/25/2020 3:51 PM, Andrew Rybchenko wrote:
> On 2/25/20 3:44 PM, Ferruh Yigit wrote:
>> For the ABI compatibility it is better to hide internal data structures
>> from the application as much as possible. But because of some inline
>> functions 'struct eth_dev_ops' can't be hidden completely.
>>
>> Plan is to split the 'struct eth_dev_ops' into two as ones used by
>> inline functions and ones not used, and hide the second part that not
>> used by inline functions completely to the application.
>>
>> Signed-off-by: Ferruh Yigit <ferruh.yi...@intel.com>
>> Acked-by: Jerin Jacob <jer...@marvell.com>
>> ---
>> Cc: David Marchand <david.march...@redhat.com>
>> Cc: Thomas Monjalon <tho...@monjalon.net>
>> Cc: Andrew Rybchenko <arybche...@solarflare.com>
>>
>> v2:
>> * Add target date for the work
>> * Give more detail on what will be done
>> ---
>> doc/guides/rel_notes/deprecation.rst | 11 +++++++++++
>> 1 file changed, 11 insertions(+)
>>
>> diff --git a/doc/guides/rel_notes/deprecation.rst
>> b/doc/guides/rel_notes/deprecation.rst
>> index 99d81564a..ff612a615 100644
>> --- a/doc/guides/rel_notes/deprecation.rst
>> +++ b/doc/guides/rel_notes/deprecation.rst
>> @@ -86,6 +86,17 @@ Deprecation Notices
>> In 19.11 PMDs will still update the field even when the offload is not
>> enabled.
>>
>> +* ethdev: Split the ``struct eth_dev_ops`` struct to hide it as much as
>> possible.
>> + Currently the ``struct eth_dev_ops`` struct is accessible by the
>> application
>> + because some inline functions, like ``rte_eth_tx_descriptor_status()``,
>> + access the struct directly. The struct will be separate in two, the ops
>> used
>> + by inline functions still will be accessible to user but rest will be
>> hidden.
>> + Initial split will be done in 20.05 with adding reserved fields for the
>> struct
>> + used by inline functions, and by putting new struct reference into public
>> one
>> + to not increase the size of ``struct rte_eth_dev``, proper split will be
>> done
>> + in 20.11 by moving inline dev_ops function to next to Rx/Tx burst
>> functions and
>> + hiding rest.
>> +
>> * cryptodev: support for using IV with all sizes is added, J0 still can
>> be used but only when IV length in following structs
>> ``rte_crypto_auth_xform``,
>> ``rte_crypto_aead_xform`` is set to zero. When IV length is greater or
>> equal
>
> I'd like to understand why do we need an intermediate solution first.
We don't need it really, we may prefer to postpone the update to 20.11.
> Also rereading above few times I've failed to fully understand what
> will be done and why it does not break API/ABI.
>
Agree it wasn't very clear, but I mean something like below, I hope it
clarifies:
Previously:
struct rte_eth_dev
+--------+
| | *dev_ops struct eth_dev_ops
| |
| +-------------->+--------+
| | | |
| | | |
| | | |
| | | |
+--------+ | |
| |
| |
| |
+--------+
Proposed:
struct rte_eth_dev
+--------+
| | struct eth_dev_ops
| |
|*dev_ops+-------------->+--------+
| | | |
| | | Reserv |
| | | |
| | | |
+--------+ | |
+--------+
| inline |
| de^_ops| struct eth_dev_ops
+--------+
| *priv +------------->+--------+
+--------+ | |
| |
| |
| |
| |
| |
| |
| |
+--------+
This is only to keep ABI compatibility [1] while separating the struct.
[1]
- The offset of some functions in the dev_ops struct should be same
- The size of the "struct rte_eth_dev" should be same
