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From: Jason Gunthorpe <jgg@ziepe.ca>
To: Stefan Berger <stefanb@linux.vnet.ibm.com>
Cc: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>,
	linux-integrity@vger.kernel.org, zohar@linux.vnet.ibm.com,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 1/4] tpm: Implement tpm_chip_find() and tpm_chip_put() for other subsystems
Date: Thu, 21 Jun 2018 11:56:01 -0600	[thread overview]
Message-ID: <20180621175601.GC19270@ziepe.ca> (raw)
In-Reply-To: <95b2970f-b71b-4cfc-c188-7ae7e8cb94c5@linux.vnet.ibm.com>

On Thu, Jun 21, 2018 at 01:45:03PM -0400, Stefan Berger wrote:
> 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@linux.vnet.ibm.com>
> >You should sort this out in a way that we don't end up with duplicate
> >functions.
> 
> Do you want me to create a function *like* tpm_chip_find_get() that takes an
> additional parameter whether to get the ops semaphore and have that function
> called by the existing tpm_chip_find_get() and the new tpm_chip_find(). The
> latter would then not get the ops semphore. I didn't want to do this since
> one time the function returns with a lock held and the other time not.

Another option, and I haven't looked, is to revise the callers of
tpm_chip_find_get to not require it to hold the ops semaphore for
them.

Either by giving them an API to do it, or revising the TPM entry
points to do it.

I didn't look, but how did the ops semaphore get grabbed in your
revised patches? They do grab it, right?

Jason

  reply	other threads:[~2018-06-21 17:56 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-06-20 20:42 [PATCH v2 0/4] Have IMA find and use a tpm_chip until system shutdown Stefan Berger
2018-06-20 20:42 ` [PATCH v2 1/4] tpm: Implement tpm_chip_find() and tpm_chip_put() for other subsystems Stefan Berger
2018-06-20 20:50   ` Jason Gunthorpe
2018-06-20 21:13     ` Stefan Berger
2018-06-21 17:13     ` Jarkko Sakkinen
2018-06-21 17:15   ` Jarkko Sakkinen
2018-06-21 17:27     ` Stefan Berger
2018-06-21 17:45     ` Stefan Berger
2018-06-21 17:56       ` Jason Gunthorpe [this message]
2018-06-21 18:19         ` Stefan Berger
2018-06-21 19:06           ` Jason Gunthorpe
2018-06-21 20:14             ` Stefan Berger
2018-06-21 20:51               ` Jason Gunthorpe
2018-06-20 20:42 ` [PATCH v2 2/4] ima: Implement ima_shutdown and register it as a reboot_notifier Stefan Berger
2018-06-20 20:42 ` [PATCH v2 3/4] ima: Use tpm_chip_find() and access TPM functions using it Stefan Berger
2018-06-21 20:53   ` Mimi Zohar
2018-06-21 20:59     ` Stefan Berger
2018-06-22  3:25       ` Jason Gunthorpe
2018-06-22 11:40         ` Stefan Berger
2018-06-22 14:19           ` Jason Gunthorpe
2018-06-20 20:42 ` [PATCH v2 4/4] ima: Get rid of ima_used_chip and use ima_tpm_chip != NULL instead Stefan Berger

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