Re: need to pick a solution for dm-crypt IV generation and do it! [was: Re: dm: submit stacked requests in irq enabled context]

[Neeraj Soni]

Until we move to some latest stable kernel as Keith mentioned.

On 5/11/2017 11:22 AM, Neeraj Soni wrote:
Thanks for inputs folks. So shall i conclude that there is no remedy 
available that can be applied on 4.4 and reverting this patch is only 
way forward to solve the degradation?


Neeraj


On 5/10/2017 8:25 PM, Gilad Ben-Yossef wrote:
On Wed, May 10, 2017 at 5:45 PM, Mike Snitzer  
wrote:

On Wed, May 10 2017 at  9:37am -0400,
Gilad Ben-Yossef  wrote:

On Wed, May 10, 2017 at 11:49 AM, Neeraj Soni 
 wrote:

Hi Keith,

Request based dm (dm-req-crypt) is being used for Disk Encryption 
solution
in Android used by Google. Also as i mentioned reverting this fix  
improves
the RR/RW numbers so this proves the request based dm is coming 
into path

and is being used.

Sadly, that is an out of tree module.

Does it still use Qcom specific APIs in its implementation 
(qcrypto_* funcs)?

It did the last time I've checked - and the driver that implements
those is not upstream either...

It makes it difficult to help - which is a shame since I am interested
in enabling higher performance
of dm-crypt when using HW based crypto transformation myself.

I have absolutely no interest in request-based dm-crypt.  It is a hack
to work-around limitations in crypto IV generation.
I agree. This is why I've said I'm interested in a high performance 
dm-crypt,
not "request based dm-crypt". They are trying to solve the same 
problem but

with the wrong solution and doing so out of upstream.

As the parlance of our time seems to go... sad. :-)


Cheers,
Gilad

Re: need to pick a solution for dm-crypt IV generation and do it! [was: Re: dm: submit stacked requests in irq enabled context]

[Neeraj Soni]

Thanks for inputs folks. So shall i conclude that there is no remedy 
available that can be applied on 4.4 and reverting this patch is only 
way forward to solve the degradation?


Neeraj


On 5/10/2017 8:25 PM, Gilad Ben-Yossef wrote:

On Wed, May 10, 2017 at 5:45 PM, Mike Snitzer  wrote:

On Wed, May 10 2017 at  9:37am -0400,
Gilad Ben-Yossef  wrote:


On Wed, May 10, 2017 at 11:49 AM, Neeraj Soni  wrote:

Hi Keith,

Request based dm (dm-req-crypt) is being used for Disk Encryption solution
in Android used by Google. Also as i mentioned reverting this fix  improves
the RR/RW numbers so this proves the request based dm is coming into path
and is being used.

Sadly, that is an out of tree module.

Does it still use Qcom specific APIs in its implementation (qcrypto_* funcs)?
It did the last time I've checked - and the driver that implements
those is not upstream either...

It makes it difficult to help - which is a shame since I am interested
in enabling higher performance
of dm-crypt when using HW based crypto transformation myself.

I have absolutely no interest in request-based dm-crypt.  It is a hack
to work-around limitations in crypto IV generation.

I agree. This is why I've said I'm interested in a high performance dm-crypt,
not "request based dm-crypt". They are trying to solve the same problem but
with the wrong solution and doing so out of upstream.

As the parlance of our time seems to go... sad. :-)


Cheers,
Gilad

Re: need to pick a solution for dm-crypt IV generation and do it! [was: Re: dm: submit stacked requests in irq enabled context]

[Gilad Ben-Yossef]

On Wed, May 10, 2017 at 5:45 PM, Mike Snitzer  wrote:
> On Wed, May 10 2017 at  9:37am -0400,
> Gilad Ben-Yossef  wrote:
>
>> On Wed, May 10, 2017 at 11:49 AM, Neeraj Soni  
>> wrote:
>> > Hi Keith,
>> >
>> > Request based dm (dm-req-crypt) is being used for Disk Encryption solution
>> > in Android used by Google. Also as i mentioned reverting this fix  improves
>> > the RR/RW numbers so this proves the request based dm is coming into path
>> > and is being used.
>>
>> Sadly, that is an out of tree module.
>>
>> Does it still use Qcom specific APIs in its implementation (qcrypto_* funcs)?
>> It did the last time I've checked - and the driver that implements
>> those is not upstream either...
>>
>> It makes it difficult to help - which is a shame since I am interested
>> in enabling higher performance
>> of dm-crypt when using HW based crypto transformation myself.
>
> I have absolutely no interest in request-based dm-crypt.  It is a hack
> to work-around limitations in crypto IV generation.

I agree. This is why I've said I'm interested in a high performance dm-crypt,
not "request based dm-crypt". They are trying to solve the same problem but
with the wrong solution and doing so out of upstream.

As the parlance of our time seems to go... sad. :-)


Cheers,
Gilad


-- 
Gilad Ben-Yossef
Chief Coffee Drinker

"If you take a class in large-scale robotics, can you end up in a
situation where the homework eats your dog?"
 -- Jean-Baptiste Queru