linux-kernel - Re: [PATCH 2/4] tpm: delete the TPM_TIS_CLK

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Message-ID: <1cde2001-9ec0-02b3-42cc-11e931c0b22a@redhat.com>
Date:   Wed, 20 Dec 2017 19:26:03 +0100
From:   Javier Martinez Canillas <javierm@...hat.com>
To:     Jason Gunthorpe <jgg@...pe.ca>,
        "Shaikh, Azhar" <azhar.shaikh@...el.com>
Cc:     "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        James Ettle <james@...le.org.uk>,
        Hans de Goede <hdegoede@...hat.com>,
        Arnd Bergmann <arnd@...db.de>,
        Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>,
        Peter Huewe <peterhuewe@....de>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        "linux-integrity@...r.kernel.org" <linux-integrity@...r.kernel.org>
Subject: Re: [PATCH 2/4] tpm: delete the TPM_TIS_CLK_ENABLE flag

On 12/20/2017 07:10 PM, Jason Gunthorpe wrote:
> On Wed, Dec 20, 2017 at 03:19:19PM +0000, Shaikh, Azhar wrote:
>>> This flag is only used to warn if CLKRUN_EN wasn't disabled on Braswell
>>> systems, but the only way this can happen is if the code is not correct.
>>>
>>> So it's an unnecessary check that just makes the code harder to read.
>>
>> This code was implemented as a suggestion from Jason on the previous patches. 
>> https://www.spinics.net/lists/linux-integrity/msg00827.html
> 
> The concept was to be like ASSERT_RTNL, maybe it just needs a suitably
> named static inline to addrress Javier's readability concerns?
>

I really think is not worth it and pollutes all the tpm_tcg_{read,write}
functions with those is_bsw() and flags checks. Your example is different
since is a core API used by in lot of places in the kernel, but it's not
the case here.

But I don't have a strong opinion either, it was Jarkko who questioned
the value of the flag so I can drop this patch too if you disagree with
the change. I'm mostly interested in PATCH 4/4 that's the actual fix.
 
> Jason
> 

Best regards,
-- 
Javier Martinez Canillas
Software Engineer - Desktop Hardware Enablement
Red Hat