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Date:   Fri, 4 Oct 2019 11:24:34 -0700
From:   Jerry Snitselaar <jsnitsel@redhat.com>
To:     James Bottomley <James.Bottomley@HansenPartnership.com>
Cc:     Mimi Zohar <zohar@linux.ibm.com>,
        Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>,
        linux-integrity@vger.kernel.org,
        Sumit Garg <sumit.garg@linaro.org>,
        Stefan Berger <stefanb@linux.vnet.ibm.com>,
        Peter Huewe <peterhuewe@gmx.de>,
        Jason Gunthorpe <jgg@ziepe.ca>, Arnd Bergmann <arnd@arndb.de>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        open list <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v3 2/2] tpm: Detach page allocation from tpm_buf
Message-ID: <20191004182434.tjwtfjzvamomybhr@cantor>
Reply-To: Jerry Snitselaar <jsnitsel@redhat.com>
Mail-Followup-To: James Bottomley <James.Bottomley@HansenPartnership.com>,
        Mimi Zohar <zohar@linux.ibm.com>,
        Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>,
        linux-integrity@vger.kernel.org, Sumit Garg <sumit.garg@linaro.org>,
        Stefan Berger <stefanb@linux.vnet.ibm.com>,
        Peter Huewe <peterhuewe@gmx.de>, Jason Gunthorpe <jgg@ziepe.ca>,
        Arnd Bergmann <arnd@arndb.de>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        open list <linux-kernel@vger.kernel.org>
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On Fri Oct 04 19, James Bottomley wrote:
>On Fri, 2019-10-04 at 13:37 -0400, Mimi Zohar wrote:
>> On Fri, 2019-10-04 at 09:37 -0700, James Bottomley wrote:
>> > On Thu, 2019-10-03 at 21:51 +0300, Jarkko Sakkinen wrote:
>> > > As has been seen recently, binding the buffer allocation and
>> > > tpm_buf
>> > > together is sometimes far from optimal.
>> >
>> > Can you elaborate on this a bit more?  I must have missed the
>> > discussion.
>>
>> Refer to e13cd21ffd50 ("tpm: Wrap the buffer from the caller to
>> tpm_buf in tpm_send()") for the details.
>
>Yes, I get that, but to my mind that calls for moving the
>tpm_init/destroy_buf into the callers of tpm_send (which, for the most
>part, already exist), which means there's no need to separate the buf
>and data lifetimes.
>
>James
>

Sumit has been working on a patchset that does this.  His patchset
converts both the asymmetric keys and trusted keys code to using the
tpm_buf manipulation functions.