[dpdk-dev] [PATCH 1/2] lib/cryptodev: add support to set session private data

[Gujjar, Abhinandan S]

Hi Akhil,

> -----Original Message-----
> From: Akhil Goyal [mailto:akhil.goyal at nxp.com]
> Sent: Tuesday, January 16, 2018 12:56 PM
> To: Gujjar, Abhinandan S <abhinandan.gujjar at intel.com>; Doherty, Declan
> <declan.doherty at intel.com>; Jacob, Jerin
> <Jerin.JacobKollanukkaran at cavium.com>
> Cc: dev at dpdk.org; Vangati, Narender <narender.vangati at intel.com>; Rao,
> Nikhil <nikhil.rao at intel.com>
> Subject: Re: [PATCH 1/2] lib/cryptodev: add support to set session private data
> 
> Hi Abhinandan,
> On 1/16/2018 12:35 PM, Gujjar, Abhinandan S wrote:
> > Hi Akhil,
> >
> >> -----Original Message-----
> >> From: Akhil Goyal [mailto:akhil.goyal at nxp.com]
> >> Sent: Tuesday, January 16, 2018 11:55 AM
> >> To: Gujjar, Abhinandan S <abhinandan.gujjar at intel.com>; Doherty,
> >> Declan <declan.doherty at intel.com>
> >> Cc: dev at dpdk.org; Vangati, Narender <narender.vangati at intel.com>;
> >> Rao, Nikhil <nikhil.rao at intel.com>
> >> Subject: Re: [PATCH 1/2] lib/cryptodev: add support to set session
> >> private data
> >>
> >> Hi Abhinandan,
> >> On 1/16/2018 11:39 AM, Gujjar, Abhinandan S wrote:
> >>>>> diff --git a/lib/librte_cryptodev/rte_crypto.h
> >>>>> b/lib/librte_cryptodev/rte_crypto.h
> >>>>> index bbc510d..3a98cbf 100644
> >>>>> --- a/lib/librte_cryptodev/rte_crypto.h
> >>>>> +++ b/lib/librte_cryptodev/rte_crypto.h
> >>>>> @@ -62,6 +62,18 @@ enum rte_crypto_op_sess_type {
> >>>>>     	RTE_CRYPTO_OP_SECURITY_SESSION	/**< Security session
> crypto
> >>>> operation */
> >>>>>     };
> >>>>>
> >>>>> +/** Private data types for cryptographic operation
> >>>>> + * @see rte_crypto_op::private_data_type */ enum
> >>>>> +rte_crypto_op_private_data_type {
> >>>>> +	RTE_CRYPTO_OP_PRIVATE_DATA_NONE,
> >>>>> +	/**< No private data */
> >>>>> +	RTE_CRYPTO_OP_PRIVATE_DATA_OP,
> >>>>> +	/**< Private data is part of rte_crypto_op and indicated by
> >>>>> +	 * private_data_offset */
> >>>>> +	RTE_CRYPTO_OP_PRIVATE_DATA_SESSION
> >>>>> +	/**< Private data is available at session */ };
> >>>>> +
> >>>> We may get away with this enum. If private_data_offset is "0", then
> >>>> we can check with the session if it has priv data or not.
> >>> Right now,  Application uses 'rte_crypto_op_private_data_type' to
> >>> indicate rte_cryptodev_sym_session_set_private_data()
> >>> was called to set the private data. Otherwise, how do you indicate
> >>> there is a
> >> private data associated with the session?
> >>> Any suggestions?
> >> For session based flows, the first choice to store the private data
> >> should be in the session. So RTE_CRYPTO_OP_WITH_SESSION or
> >> RTE_CRYPTO_OP_SECURITY_SESSION can be used to call
> >> rte_cryptodev_sym_session_set_private_data or
> >> rte_security_session_set_private_data.
> > Case 1: private_data_offset is "0" and sess_type =
> > RTE_CRYPTO_OP_WITH_SESSION -> usual case Case 2: private_data_offset
> > is "0" and sess_type = RTE_CRYPTO_OP_WITH_SESSION + event case (access
> > private data) Differentiating between case 1 & 2 will be done by checking
> rte_crypto_op_private_data_type ==
> RTE_CRYPTO_OP_PRIVATE_DATA_SESSION.
> 
> Consider this:
> if (sess_type == RTE_CRYPTO_OP_WITH_SESSION &&
> 		rte_cryptodev_sym_session_get_private_data == NULL)
> 	usual case.
> else if (sess_type = RTE_CRYPTO_OP_WITH_SESSION &&
> 		rte_cryptodev_sym_session_get_private_data != NULL)
> 	event case.
> else if (sess_type == RTE_CRYPTO_OP_SESSIONLESS &&
> 		private_data_offset != 0)
> 	event case for sessionless op.
> 
> I hope all cases can be handled in this way.
Memory allocated for private data will be continuation of session memory.
I think, rte_cryptodev_sym_session_get_private_data() will return a valid pointer.
It could be pointer to private data, in case application has allocated mempool with session + private data.
It could be again a pointer to a location(may be next session),  in case application has allocated mempool with session only.
Unless, there is a flag in the session data which will be set by rte_cryptodev_sym_session_set_private_data()
If this flag is not set, rte_cryptodev_sym_session_get_private_data() will return NULL.
I am not claiming, I have complete knowledge of different usage case of mempool setup for crypto.
I am wondering, whether I am missing anything here. Please let me know.
> 
> 
> -Akhil
-Abhinandan