linux-kernel - Re: [PATCH v2 1/4] tpm: Implement tpm_chip_find() and tpm_chip

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Message-Id: <c74308ff-9fd1-1779-0432-e7cacbed769f@linux.vnet.ibm.com>
Date:   Thu, 21 Jun 2018 13:27:33 -0400
From:   Stefan Berger <stefanb@...ux.vnet.ibm.com>
To:     Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
Cc:     linux-integrity@...r.kernel.org, zohar@...ux.vnet.ibm.com,
        jgg@...pe.ca, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 1/4] tpm: Implement tpm_chip_find() and tpm_chip_put()
 for other subsystems

On 06/21/2018 01:15 PM, Jarkko Sakkinen wrote:
> On Wed, Jun 20, 2018 at 04:42:33PM -0400, Stefan Berger wrote:
>> Implement tpm_chip_find() for other subsystems to find a TPM chip and
>> get a reference to that chip. Once done with using the chip, the reference
>> is released using tpm_chip_put().
>>
>> Signed-off-by: Stefan Berger <stefanb@...ux.vnet.ibm.com>
> You should sort this out in a way that we don't end up with duplicate
> functions.

We cannot hold the ops_sem semaphore for a long time. So we need a 
function that gets us a reference and doesn't hold the ops semaphore and 
that's where this tpm_chip_find() comes from.

    Stefan

> /Jarkko
>