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Date: Wed, 25 Oct 2017 09:18:59 -0600
From: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
To: PrasannaKumar Muralidharan <prasannatsmkumar@gmail.com>
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>,
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        "open list:KEYS-TRUSTED" <keyrings@vger.kernel.org>,
        "open list:HARDWARE RANDOM NUMBER GENERATOR CORE" 
        <linux-crypto@vger.kernel.org>,
        James Morris <james.l.morris@oracle.com>,
        Matt Mackall <mpm@selenic.com>, David Safford <safford@us.ibm.com>,
        Mimi Zohar <zohar@linux.vnet.ibm.com>,
        "Serge E. Hallyn" <serge@hallyn.com>
Subject: Re: [PATCH] tpm: Move Linux RNG connection to hwrng
Message-ID: <20171025151859.GB15557@obsidianresearch.com>
References: <20171024184235.GC1806@obsidianresearch.com>
 <CANc+2y5q78g1Ow1JQ7kO0SkPrgNtbRV=COkB4YLHbSraTQH7aQ@mail.gmail.com>
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On Wed, Oct 25, 2017 at 08:15:09PM +0530, PrasannaKumar Muralidharan
wrote:

> > +static int tpm_add_hwrng(struct tpm_chip *chip)
> > +{
> > +       if (!IS_ENABLED(CONFIG_HW_RANDOM_TPM))
> > +               return 0;
> 
> Can #ifndef CONFIG_HW_RANDOM_TPM be used instead? That way an if
> condition can be avoided.

Generally speaking IS_ENABLED is prefered over #ifdef as it reduces the
set of compilation combinations.

Jason