[PATCH v2] doc: announce ABI change for cryptodev config

[Anoob Joseph <anoobj@marvell.com>]

Add new field ff_disable in rte_cryptodev_config. This enables
applications to control the features enabled on the crypto device.

Proposed new layout:

/** Crypto device configuration structure */
struct rte_cryptodev_config {
    int socket_id;            /**< Socket to allocate resources on */
    uint16_t nb_queue_pairs;
    /**< Number of queue pairs to configure on device */
+   uint64_t ff_disable;
+   /**< Feature flags to be disabled. Only the following features are
+    * allowed to be disabled,
+    *  - RTE_CRYPTODEV_FF_SYMMETRIC_CRYPTO
+    *  - RTE_CRYPTODEV_FF_ASYMMETRIC_CRYPTO
+    *  - RTE_CRYTPODEV_FF_SECURITY
+    */
};

For eth devices, rte_eth_conf.rx_mode.offloads and
rte_eth_conf.tx_mode.offloads fields are used by applications to
control the offloads enabled on the eth device. This proposal adds a
similar ability for the crypto device.

Signed-off-by: Anoob Joseph <anoobj@marvell.com>
---
v2:
* Renamed 'ff_enable' to 'ff_disable'

 doc/guides/rel_notes/deprecation.rst | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/doc/guides/rel_notes/deprecation.rst b/doc/guides/rel_notes/deprecation.rst
index 1b4fcb7..d0a60f9 100644
--- a/doc/guides/rel_notes/deprecation.rst
+++ b/doc/guides/rel_notes/deprecation.rst
@@ -75,3 +75,17 @@ Deprecation Notices
 
 * crypto/aesni_mb: the minimum supported intel-ipsec-mb library version will be
   changed from 0.49.0 to 0.52.0.
+
+* cryptodev: New member in ``rte_cryptodev_config`` to allow applications to
+  disable features supported by the crypto device. Only the following features
+  would be allowed to be disabled this way,
+
+  - ``RTE_CRYPTODEV_FF_SYMMETRIC_CRYPTO``
+  - ``RTE_CRYPTODEV_FF_ASYMMETRIC_CRYPTO``
+  - ``RTE_CRYPTODEV_FF_SECURITY``
+
+  Disabling unused features would facilitate efficient usage of HW/SW offload.
+
+  - Member ``uint64_t ff_disable`` in ``rte_cryptodev_config``
+
+  The field would be added in v19.08.
-- 
2.7.4