From: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Subject: Re: [tpmdd-devel] [PATCH] tpm: remove chip_num parameter from
 in-kernel API
Date: Tue, 24 Oct 2017 11:46:37 -0600
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Cc: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>,
        Stefan Berger <stefanb@linux.vnet.ibm.com>,
        linux-integrity@vger.kernel.org,
        David Howells <dhowells@redhat.com>,
        Herbert Xu <herbert@gondor.apana.org.au>,
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        <linux-ima-user@lists.sourceforge.net>,
        Dmitry Kasatkin <dmitry.kasatkin@gmail.com>,
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        linux-security-module@vger.kernel.org,
        "moderated list:TPM DEVICE DRIVER"
        <tpmdd-devel@lists.sourceforge.net>,
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        <linux-crypto@vger.kernel.org>,
        James Morris <james.l.morris@oracle.com>,
        Matt Mackall <mpm@selenic.com>,
        "open list:INTEGRITY MEASUREMENT ARCHITECTURE IMA"
To: PrasannaKumar Muralidharan <prasannatsmkumar@gmail.com>
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On Tue, Oct 24, 2017 at 09:44:30PM +0530, PrasannaKumar Muralidharan wrote:

> I am wondering why it is wrong. Isn't the chip id valid till it is
> unregistered? If so the rfc is correct. Please explain, may be I am
> missing something.

The lifetime is a bit complicated, but the general rule in the kernel
for things like this it to use pointers, not ids, and certainly not
string ids.

For that patch it could just use container_of to get the chip..

Jason