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Subject: Re: [PATCH v3 0/2] tpm: add support for nonblocking operation
To:     Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Cc:     jgg@ziepe.ca, linux-integrity@vger.kernel.org,
        linux-security-module@vger.kernel.org,
        linux-kernel@vger.kernel.org, philip.b.tricca@intel.com,
        James.Bottomley@HansenPartnership.com,
        "Dock, Deneen T" <deneen.t.dock@intel.com>
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 <20180619131046.GC5609@linux.intel.com>
 <e402d3d0-d9de-35a9-d434-d472d8f68e62@intel.com>
 <20180621171746.GJ11859@linux.intel.com>
From:   Tadeusz Struk <tadeusz.struk@intel.com>
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Date:   Thu, 21 Jun 2018 10:36:20 -0700
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On 06/21/2018 10:17 AM, Jarkko Sakkinen wrote:
> On Tue, Jun 19, 2018 at 05:45:35PM -0700, Tadeusz Struk wrote:
>> Hi Jarkko,
>> Thanks for reviewing the patch.
>> There are applications/frameworks where a worker thread is not an option.
>> Take for example the IoT use-cases and frameworks like IoT.js, or "Node.js for IoT".
>> They are all single threaded, event-driven frameworks, using non-blocking I/O as the base of their processing model.
>> Similarly embedded applications, which are basically just a single threaded event loop, quite often don't use threads because of resources constrains.
>>
>> If your concern is that user space will not adopt to this, I can say that TSS library [1] is currently blocked on this feature, and we can not enable some of the use-cases mentioned above because of this.
>>
>> Thanks,
>> Tadeusz
>>
>> [1] https://github.com/tpm2-software/tpm2-tss
> 
> I put this into "mathematical" terms. TPM is by nature is blocking. It
> does not scale this way so you are essentially just simulating
> non-blocking behaviour.
> 

That is correct, and this is exactly why we need this.
Thanks,
-- 
Tadeusz