[1/2] cryptodev: add min headroom and tailroom requirement

  Enabling crypto devs to specify the minimum headroom and tailroom it
expects in the mbuf. For net PMDs, standard headroom has to be honoured
by applications, which is not strictly followed for crypto devs. This
prevents crypto devs from using free space in mbuf (available as
head/tailroom) for internal requirements in crypto operations. Addition
of head/tailroom requirement will help PMDs to communicate such
requirements to the application.

The availability and use of head/tailroom is an optimization if the
hardware supports use of head/tailroom for crypto-op info. For devices
that do not support using the head/tailroom, they can continue to operate
without any performance-drop.

Signed-off-by: Anoob Joseph <anoob.joseph@caviumnetworks.com>
---
 doc/guides/rel_notes/deprecation.rst | 4 ++++
 lib/librte_cryptodev/rte_cryptodev.h | 6 ++++++
 2 files changed, 10 insertions(+)
  

On 6/19/2018 11:56 AM, Anoob Joseph wrote:
> Enabling crypto devs to specify the minimum headroom and tailroom it
> expects in the mbuf. For net PMDs, standard headroom has to be honoured
> by applications, which is not strictly followed for crypto devs. This
> prevents crypto devs from using free space in mbuf (available as
> head/tailroom) for internal requirements in crypto operations. Addition
> of head/tailroom requirement will help PMDs to communicate such
> requirements to the application.
>
> The availability and use of head/tailroom is an optimization if the
> hardware supports use of head/tailroom for crypto-op info. For devices
> that do not support using the head/tailroom, they can continue to operate
> without any performance-drop.
>
> Signed-off-by: Anoob Joseph <anoob.joseph@caviumnetworks.com>
> ---
>   doc/guides/rel_notes/deprecation.rst | 4 ++++
>   lib/librte_cryptodev/rte_cryptodev.h | 6 ++++++
>   2 files changed, 10 insertions(+)
>
> diff --git a/doc/guides/rel_notes/deprecation.rst b/doc/guides/rel_notes/deprecation.rst
> index 1ce692e..a547289 100644
> --- a/doc/guides/rel_notes/deprecation.rst
> +++ b/doc/guides/rel_notes/deprecation.rst
> @@ -122,3 +122,7 @@ Deprecation Notices
>     - Function ``rte_cryptodev_get_private_session_size()`` will be deprecated
>       in 18.05, and it gets replaced with ``rte_cryptodev_sym_get_private_session_size()``.
>       It will be removed in 18.08.
> +  - New field, ``min_headroom_req``, added in ``rte_cryptodev_info`` structure. It will be
> +    added in 18.11.
> +  - New field, ``min_tailroom_req``, added in ``rte_cryptodev_info`` structure. It will be
> +    added in 18.11.

Is this targeted for 18.08 or 18.11?

> diff --git a/lib/librte_cryptodev/rte_cryptodev.h b/lib/librte_cryptodev/rte_cryptodev.h
> index 92ce6d4..fa944b8 100644
> --- a/lib/librte_cryptodev/rte_cryptodev.h
> +++ b/lib/librte_cryptodev/rte_cryptodev.h
> @@ -382,6 +382,12 @@ struct rte_cryptodev_info {
>   	unsigned max_nb_queue_pairs;
>   	/**< Maximum number of queues pairs supported by device. */
>   
> +	uint32_t min_headroom_req;
> +	/**< Minimum mbuf headroom required by device */
> +
> +	uint32_t min_tailroom_req;
> +	/**< Minimum mbuf tailroom required by device */
> +
>   	struct {
>   		unsigned max_nb_sessions;
>   		/**< Maximum number of sessions supported by device. */
  

Hi Akhil,

The change adds couple of entries in cryptodev_info structure. I was 
under the impression this will be an ABI change and would need one 
release cycle. If we can get this through in 18.08, it would be great. 
Do you want me to revise the patch stating it that way?

Thanks,
Anoob
On 21-06-2018 19:54, Akhil Goyal wrote:
>
> On 6/19/2018 11:56 AM, Anoob Joseph wrote:
>> Enabling crypto devs to specify the minimum headroom and tailroom it
>> expects in the mbuf. For net PMDs, standard headroom has to be honoured
>> by applications, which is not strictly followed for crypto devs. This
>> prevents crypto devs from using free space in mbuf (available as
>> head/tailroom) for internal requirements in crypto operations. Addition
>> of head/tailroom requirement will help PMDs to communicate such
>> requirements to the application.
>>
>> The availability and use of head/tailroom is an optimization if the
>> hardware supports use of head/tailroom for crypto-op info. For devices
>> that do not support using the head/tailroom, they can continue to 
>> operate
>> without any performance-drop.
>>
>> Signed-off-by: Anoob Joseph <anoob.joseph@caviumnetworks.com>
>> ---
>>   doc/guides/rel_notes/deprecation.rst | 4 ++++
>>   lib/librte_cryptodev/rte_cryptodev.h | 6 ++++++
>>   2 files changed, 10 insertions(+)
>>
>> diff --git a/doc/guides/rel_notes/deprecation.rst 
>> b/doc/guides/rel_notes/deprecation.rst
>> index 1ce692e..a547289 100644
>> --- a/doc/guides/rel_notes/deprecation.rst
>> +++ b/doc/guides/rel_notes/deprecation.rst
>> @@ -122,3 +122,7 @@ Deprecation Notices
>>     - Function ``rte_cryptodev_get_private_session_size()`` will be 
>> deprecated
>>       in 18.05, and it gets replaced with 
>> ``rte_cryptodev_sym_get_private_session_size()``.
>>       It will be removed in 18.08.
>> +  - New field, ``min_headroom_req``, added in ``rte_cryptodev_info`` 
>> structure. It will be
>> +    added in 18.11.
>> +  - New field, ``min_tailroom_req``, added in ``rte_cryptodev_info`` 
>> structure. It will be
>> +    added in 18.11.
>
> Is this targeted for 18.08 or 18.11?
>
>> diff --git a/lib/librte_cryptodev/rte_cryptodev.h 
>> b/lib/librte_cryptodev/rte_cryptodev.h
>> index 92ce6d4..fa944b8 100644
>> --- a/lib/librte_cryptodev/rte_cryptodev.h
>> +++ b/lib/librte_cryptodev/rte_cryptodev.h
>> @@ -382,6 +382,12 @@ struct rte_cryptodev_info {
>>       unsigned max_nb_queue_pairs;
>>       /**< Maximum number of queues pairs supported by device. */
>>
>> +     uint32_t min_headroom_req;
>> +     /**< Minimum mbuf headroom required by device */
>> +
>> +     uint32_t min_tailroom_req;
>> +     /**< Minimum mbuf tailroom required by device */
>> +
>>       struct {
>>               unsigned max_nb_sessions;
>>               /**< Maximum number of sessions supported by device. */
>
  

Hi Anoob,


On 6/22/2018 12:22 PM, Joseph, Anoob wrote:
> Hi Akhil,
>
> The change adds couple of entries in cryptodev_info structure. I was 
> under the impression this will be an ABI change and would need one 
> release cycle. If we can get this through in 18.08, it would be great. 
> Do you want me to revise the patch stating it that way?

If you are adding a deprecation notice for next release, then you cannot add code in that release.

To add this in current release, I think Pablo can take a decision on this.


>
> Thanks,
> Anoob
> On 21-06-2018 19:54, Akhil Goyal wrote:
>>
>> On 6/19/2018 11:56 AM, Anoob Joseph wrote:
>>> Enabling crypto devs to specify the minimum headroom and tailroom it
>>> expects in the mbuf. For net PMDs, standard headroom has to be honoured
>>> by applications, which is not strictly followed for crypto devs. This
>>> prevents crypto devs from using free space in mbuf (available as
>>> head/tailroom) for internal requirements in crypto operations. Addition
>>> of head/tailroom requirement will help PMDs to communicate such
>>> requirements to the application.
>>>
>>> The availability and use of head/tailroom is an optimization if the
>>> hardware supports use of head/tailroom for crypto-op info. For devices
>>> that do not support using the head/tailroom, they can continue to 
>>> operate
>>> without any performance-drop.
>>>
>>> Signed-off-by: Anoob Joseph <anoob.joseph@caviumnetworks.com>
>>> ---
>>>   doc/guides/rel_notes/deprecation.rst | 4 ++++
>>>   lib/librte_cryptodev/rte_cryptodev.h | 6 ++++++
>>>   2 files changed, 10 insertions(+)
>>>
>>> diff --git a/doc/guides/rel_notes/deprecation.rst 
>>> b/doc/guides/rel_notes/deprecation.rst
>>> index 1ce692e..a547289 100644
>>> --- a/doc/guides/rel_notes/deprecation.rst
>>> +++ b/doc/guides/rel_notes/deprecation.rst
>>> @@ -122,3 +122,7 @@ Deprecation Notices
>>>     - Function ``rte_cryptodev_get_private_session_size()`` will be 
>>> deprecated
>>>       in 18.05, and it gets replaced with 
>>> ``rte_cryptodev_sym_get_private_session_size()``.
>>>       It will be removed in 18.08.
>>> +  - New field, ``min_headroom_req``, added in 
>>> ``rte_cryptodev_info`` structure. It will be
>>> +    added in 18.11.
>>> +  - New field, ``min_tailroom_req``, added in 
>>> ``rte_cryptodev_info`` structure. It will be
>>> +    added in 18.11.
>>
>> Is this targeted for 18.08 or 18.11?
>>
>>> diff --git a/lib/librte_cryptodev/rte_cryptodev.h 
>>> b/lib/librte_cryptodev/rte_cryptodev.h
>>> index 92ce6d4..fa944b8 100644
>>> --- a/lib/librte_cryptodev/rte_cryptodev.h
>>> +++ b/lib/librte_cryptodev/rte_cryptodev.h
>>> @@ -382,6 +382,12 @@ struct rte_cryptodev_info {
>>>       unsigned max_nb_queue_pairs;
>>>       /**< Maximum number of queues pairs supported by device. */
>>>
>>> +     uint32_t min_headroom_req;
>>> +     /**< Minimum mbuf headroom required by device */
>>> +
>>> +     uint32_t min_tailroom_req;
>>> +     /**< Minimum mbuf tailroom required by device */
>>> +
>>>       struct {
>>>               unsigned max_nb_sessions;
>>>               /**< Maximum number of sessions supported by device. */
>>
>
  

On 19/06/2018 7:26 AM, Anoob Joseph wrote:
> Enabling crypto devs to specify the minimum headroom and tailroom it
> expects in the mbuf. For net PMDs, standard headroom has to be honoured
> by applications, which is not strictly followed for crypto devs. This

How is this done for NET PMDs, I don't see anything explicit in the 
ehtdev API for specification of headroom requirements.

> prevents crypto devs from using free space in mbuf (available as
> head/tailroom) for internal requirements in crypto operations. Addition
> of head/tailroom requirement will help PMDs to communicate such
> requirements to the application.
> 
> The availability and use of head/tailroom is an optimization if the
> hardware supports use of head/tailroom for crypto-op info. For devices
> that do not support using the head/tailroom, they can continue to operate
> without any performance-drop.
> 
Is there any variations in requirements for terms headroom/tailroom on a 
per algorithmic basis or is it purely for the device?

> Signed-off-by: Anoob Joseph <anoob.joseph@caviumnetworks.com>
> ---
>   doc/guides/rel_notes/deprecation.rst | 4 ++++
>   lib/librte_cryptodev/rte_cryptodev.h | 6 ++++++
>   2 files changed, 10 insertions(+)
> 
> diff --git a/doc/guides/rel_notes/deprecation.rst b/doc/guides/rel_notes/deprecation.rst
> index 1ce692e..a547289 100644
> --- a/doc/guides/rel_notes/deprecation.rst
> +++ b/doc/guides/rel_notes/deprecation.rst
> @@ -122,3 +122,7 @@ Deprecation Notices
>     - Function ``rte_cryptodev_get_private_session_size()`` will be deprecated
>       in 18.05, and it gets replaced with ``rte_cryptodev_sym_get_private_session_size()``.
>       It will be removed in 18.08.
> +  - New field, ``min_headroom_req``, added in ``rte_cryptodev_info`` structure. It will be
> +    added in 18.11.
> +  - New field, ``min_tailroom_req``, added in ``rte_cryptodev_info`` structure. It will be
> +    added in 18.11.
> diff --git a/lib/librte_cryptodev/rte_cryptodev.h b/lib/librte_cryptodev/rte_cryptodev.h
> index 92ce6d4..fa944b8 100644
> --- a/lib/librte_cryptodev/rte_cryptodev.h
> +++ b/lib/librte_cryptodev/rte_cryptodev.h
> @@ -382,6 +382,12 @@ struct rte_cryptodev_info {
>   	unsigned max_nb_queue_pairs;
>   	/**< Maximum number of queues pairs supported by device. */
>   
> +	uint32_t min_headroom_req;
> +	/**< Minimum mbuf headroom required by device */
> +
> +	uint32_t min_tailroom_req;
> +	/**< Minimum mbuf tailroom required by device */
> +
>   	struct {
>   		unsigned max_nb_sessions;
>   		/**< Maximum number of sessions supported by device. */
>
  

Hi Declan,

Please see inline.

Thanks,

Anoob


On 26-06-2018 15:42, Doherty, Declan wrote:
> External Email
>
> On 19/06/2018 7:26 AM, Anoob Joseph wrote:
>> Enabling crypto devs to specify the minimum headroom and tailroom it
>> expects in the mbuf. For net PMDs, standard headroom has to be honoured
>> by applications, which is not strictly followed for crypto devs. This
>
> How is this done for NET PMDs, I don't see anything explicit in the
> ehtdev API for specification of headroom requirements.
In rte_mbuf.h, the minimum size required for packets involved in rx/tx 
is specified and that considers headroom also. Applications usually use 
these default macros while creating mbufs which are involved in rx/tx.
https://git.dpdk.org/dpdk/tree/lib/librte_mbuf/rte_mbuf.h#n411
>
>> prevents crypto devs from using free space in mbuf (available as
>> head/tailroom) for internal requirements in crypto operations. Addition
>> of head/tailroom requirement will help PMDs to communicate such
>> requirements to the application.
>>
>> The availability and use of head/tailroom is an optimization if the
>> hardware supports use of head/tailroom for crypto-op info. For devices
>> that do not support using the head/tailroom, they can continue to 
>> operate
>> without any performance-drop.
>>
> Is there any variations in requirements for terms headroom/tailroom on a
> per algorithmic basis or is it purely for the device?
It is purely per device basis. The device can specify upper bounds for 
the head/tailroom. A device that even specified the room, may not even 
use the entire room in all cases. So it doesn't have to be algo specific.
>
>> Signed-off-by: Anoob Joseph <anoob.joseph@caviumnetworks.com>
>> ---
>>   doc/guides/rel_notes/deprecation.rst | 4 ++++
>>   lib/librte_cryptodev/rte_cryptodev.h | 6 ++++++
>>   2 files changed, 10 insertions(+)
>>
>> diff --git a/doc/guides/rel_notes/deprecation.rst 
>> b/doc/guides/rel_notes/deprecation.rst
>> index 1ce692e..a547289 100644
>> --- a/doc/guides/rel_notes/deprecation.rst
>> +++ b/doc/guides/rel_notes/deprecation.rst
>> @@ -122,3 +122,7 @@ Deprecation Notices
>>     - Function ``rte_cryptodev_get_private_session_size()`` will be 
>> deprecated
>>       in 18.05, and it gets replaced with 
>> ``rte_cryptodev_sym_get_private_session_size()``.
>>       It will be removed in 18.08.
>> +  - New field, ``min_headroom_req``, added in ``rte_cryptodev_info`` 
>> structure. It will be
>> +    added in 18.11.
>> +  - New field, ``min_tailroom_req``, added in ``rte_cryptodev_info`` 
>> structure. It will be
>> +    added in 18.11.
>> diff --git a/lib/librte_cryptodev/rte_cryptodev.h 
>> b/lib/librte_cryptodev/rte_cryptodev.h
>> index 92ce6d4..fa944b8 100644
>> --- a/lib/librte_cryptodev/rte_cryptodev.h
>> +++ b/lib/librte_cryptodev/rte_cryptodev.h
>> @@ -382,6 +382,12 @@ struct rte_cryptodev_info {
>>       unsigned max_nb_queue_pairs;
>>       /**< Maximum number of queues pairs supported by device. */
>>
>> +     uint32_t min_headroom_req;
>> +     /**< Minimum mbuf headroom required by device */
>> +
>> +     uint32_t min_tailroom_req;
>> +     /**< Minimum mbuf tailroom required by device */
>> +
>>       struct {
>>               unsigned max_nb_sessions;
>>               /**< Maximum number of sessions supported by device. */
>>
>
  

Hi Anoob,

> -----Original Message-----
> From: Joseph, Anoob [mailto:Anoob.Joseph@caviumnetworks.com]
> Sent: Thursday, June 28, 2018 3:56 AM
> To: Doherty, Declan <declan.doherty@intel.com>; De Lara Guarch, Pablo
> <pablo.de.lara.guarch@intel.com>
> Cc: Akhil Goyal <akhil.goyal@nxp.com>; Ankur Dwivedi
> <ankur.dwivedi@caviumnetworks.com>; Jerin Jacob
> <jerin.jacob@caviumnetworks.com>; Narayana Prasad
> <narayanaprasad.athreya@caviumnetworks.com>; dev@dpdk.org
> Subject: Re: [PATCH 1/2] cryptodev: add min headroom and tailroom
> requirement
> 
> Hi Declan,
> 
> Please see inline.
> 
> Thanks,
> 
> Anoob
> 
> 
> On 26-06-2018 15:42, Doherty, Declan wrote:
> > External Email
> >
> > On 19/06/2018 7:26 AM, Anoob Joseph wrote:
> >> Enabling crypto devs to specify the minimum headroom and tailroom it
> >> expects in the mbuf. For net PMDs, standard headroom has to be
> >> honoured by applications, which is not strictly followed for crypto
> >> devs. This
> >
> > How is this done for NET PMDs, I don't see anything explicit in the
> > ehtdev API for specification of headroom requirements.
> In rte_mbuf.h, the minimum size required for packets involved in rx/tx is
> specified and that considers headroom also. Applications usually use these
> default macros while creating mbufs which are involved in rx/tx.
> https://git.dpdk.org/dpdk/tree/lib/librte_mbuf/rte_mbuf.h#n411
> >
> >> prevents crypto devs from using free space in mbuf (available as
> >> head/tailroom) for internal requirements in crypto operations.
> >> Addition of head/tailroom requirement will help PMDs to communicate
> >> such requirements to the application.
> >>
> >> The availability and use of head/tailroom is an optimization if the
> >> hardware supports use of head/tailroom for crypto-op info. For
> >> devices that do not support using the head/tailroom, they can
> >> continue to operate without any performance-drop.
> >>
> > Is there any variations in requirements for terms headroom/tailroom on
> > a per algorithmic basis or is it purely for the device?
> It is purely per device basis. The device can specify upper bounds for the
> head/tailroom. A device that even specified the room, may not even use the
> entire room in all cases. So it doesn't have to be algo specific.
> >
> >> Signed-off-by: Anoob Joseph <anoob.joseph@caviumnetworks.com>
> >> ---
> >>   doc/guides/rel_notes/deprecation.rst | 4 ++++
> >>   lib/librte_cryptodev/rte_cryptodev.h | 6 ++++++
> >>   2 files changed, 10 insertions(+)
> >>
> >> diff --git a/doc/guides/rel_notes/deprecation.rst
> >> b/doc/guides/rel_notes/deprecation.rst
> >> index 1ce692e..a547289 100644
> >> --- a/doc/guides/rel_notes/deprecation.rst
> >> +++ b/doc/guides/rel_notes/deprecation.rst
> >> @@ -122,3 +122,7 @@ Deprecation Notices
> >>     - Function ``rte_cryptodev_get_private_session_size()`` will be
> >> deprecated
> >>       in 18.05, and it gets replaced with
> >> ``rte_cryptodev_sym_get_private_session_size()``.
> >>       It will be removed in 18.08.
> >> +  - New field, ``min_headroom_req``, added in ``rte_cryptodev_info``
> >> structure. It will be
> >> +    added in 18.11.
> >> +  - New field, ``min_tailroom_req``, added in ``rte_cryptodev_info``
> >> structure. It will be
> >> +    added in 18.11.
> >> diff --git a/lib/librte_cryptodev/rte_cryptodev.h
> >> b/lib/librte_cryptodev/rte_cryptodev.h
> >> index 92ce6d4..fa944b8 100644
> >> --- a/lib/librte_cryptodev/rte_cryptodev.h
> >> +++ b/lib/librte_cryptodev/rte_cryptodev.h
> >> @@ -382,6 +382,12 @@ struct rte_cryptodev_info {
> >>       unsigned max_nb_queue_pairs;
> >>       /**< Maximum number of queues pairs supported by device. */
> >>
> >> +     uint32_t min_headroom_req;
> >> +     /**< Minimum mbuf headroom required by device */
> >> +
> >> +     uint32_t min_tailroom_req;
> >> +     /**< Minimum mbuf tailroom required by device */

I would add the word "mbuf" here, in the variable names (e.g. min_mbuf_headroom_req),
to be more explicit.

Also, just let you know that we are currently modifying the info structure in this release.
Therefore, I think we could make these changes in now and then you don't need to add deprecation notices on this,
but better to add the API Change in release notes.
  

Hi Pablo,

On 28-06-2018 17:11, De Lara Guarch, Pablo wrote:
> External Email
>
> Hi Anoob,
>
>> -----Original Message-----
>> From: Joseph, Anoob [mailto:Anoob.Joseph@caviumnetworks.com]
>> Sent: Thursday, June 28, 2018 3:56 AM
>> To: Doherty, Declan <declan.doherty@intel.com>; De Lara Guarch, Pablo
>> <pablo.de.lara.guarch@intel.com>
>> Cc: Akhil Goyal <akhil.goyal@nxp.com>; Ankur Dwivedi
>> <ankur.dwivedi@caviumnetworks.com>; Jerin Jacob
>> <jerin.jacob@caviumnetworks.com>; Narayana Prasad
>> <narayanaprasad.athreya@caviumnetworks.com>; dev@dpdk.org
>> Subject: Re: [PATCH 1/2] cryptodev: add min headroom and tailroom
>> requirement
>>
>> Hi Declan,
>>
>> Please see inline.
>>
>> Thanks,
>>
>> Anoob
>>
>>
>> On 26-06-2018 15:42, Doherty, Declan wrote:
>>> External Email
>>>
>>> On 19/06/2018 7:26 AM, Anoob Joseph wrote:
>>>> Enabling crypto devs to specify the minimum headroom and tailroom it
>>>> expects in the mbuf. For net PMDs, standard headroom has to be
>>>> honoured by applications, which is not strictly followed for crypto
>>>> devs. This
>>> How is this done for NET PMDs, I don't see anything explicit in the
>>> ehtdev API for specification of headroom requirements.
>> In rte_mbuf.h, the minimum size required for packets involved in rx/tx is
>> specified and that considers headroom also. Applications usually use these
>> default macros while creating mbufs which are involved in rx/tx.
>> https://git.dpdk.org/dpdk/tree/lib/librte_mbuf/rte_mbuf.h#n411
>>>> prevents crypto devs from using free space in mbuf (available as
>>>> head/tailroom) for internal requirements in crypto operations.
>>>> Addition of head/tailroom requirement will help PMDs to communicate
>>>> such requirements to the application.
>>>>
>>>> The availability and use of head/tailroom is an optimization if the
>>>> hardware supports use of head/tailroom for crypto-op info. For
>>>> devices that do not support using the head/tailroom, they can
>>>> continue to operate without any performance-drop.
>>>>
>>> Is there any variations in requirements for terms headroom/tailroom on
>>> a per algorithmic basis or is it purely for the device?
>> It is purely per device basis. The device can specify upper bounds for the
>> head/tailroom. A device that even specified the room, may not even use the
>> entire room in all cases. So it doesn't have to be algo specific.
>>>> Signed-off-by: Anoob Joseph <anoob.joseph@caviumnetworks.com>
>>>> ---
>>>>    doc/guides/rel_notes/deprecation.rst | 4 ++++
>>>>    lib/librte_cryptodev/rte_cryptodev.h | 6 ++++++
>>>>    2 files changed, 10 insertions(+)
>>>>
>>>> diff --git a/doc/guides/rel_notes/deprecation.rst
>>>> b/doc/guides/rel_notes/deprecation.rst
>>>> index 1ce692e..a547289 100644
>>>> --- a/doc/guides/rel_notes/deprecation.rst
>>>> +++ b/doc/guides/rel_notes/deprecation.rst
>>>> @@ -122,3 +122,7 @@ Deprecation Notices
>>>>      - Function ``rte_cryptodev_get_private_session_size()`` will be
>>>> deprecated
>>>>        in 18.05, and it gets replaced with
>>>> ``rte_cryptodev_sym_get_private_session_size()``.
>>>>        It will be removed in 18.08.
>>>> +  - New field, ``min_headroom_req``, added in ``rte_cryptodev_info``
>>>> structure. It will be
>>>> +    added in 18.11.
>>>> +  - New field, ``min_tailroom_req``, added in ``rte_cryptodev_info``
>>>> structure. It will be
>>>> +    added in 18.11.
>>>> diff --git a/lib/librte_cryptodev/rte_cryptodev.h
>>>> b/lib/librte_cryptodev/rte_cryptodev.h
>>>> index 92ce6d4..fa944b8 100644
>>>> --- a/lib/librte_cryptodev/rte_cryptodev.h
>>>> +++ b/lib/librte_cryptodev/rte_cryptodev.h
>>>> @@ -382,6 +382,12 @@ struct rte_cryptodev_info {
>>>>        unsigned max_nb_queue_pairs;
>>>>        /**< Maximum number of queues pairs supported by device. */
>>>>
>>>> +     uint32_t min_headroom_req;
>>>> +     /**< Minimum mbuf headroom required by device */
>>>> +
>>>> +     uint32_t min_tailroom_req;
>>>> +     /**< Minimum mbuf tailroom required by device */
> I would add the word "mbuf" here, in the variable names (e.g. min_mbuf_headroom_req),
> to be more explicit.
Will revise the patch with this change.
>
> Also, just let you know that we are currently modifying the info structure in this release.
> Therefore, I think we could make these changes in now and then you don't need to add deprecation notices on this,
> but better to add the API Change in release notes.
Will do so.

Thanks,
Anoob