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From:   <Peter.Huewe@infineon.com>
To:     <jarkko@kernel.org>, <LinoSanfilippo@gmx.de>
CC:     <peterhuewe@gmx.de>, <jgg@ziepe.ca>, <stefanb@linux.vnet.ibm.com>,
        <James.Bottomley@hansenpartnership.com>, <keescook@chromium.org>,
        <jsnitsel@redhat.com>, <ml.linux@elloe.vision>,
        <linux-integrity@vger.kernel.org>, <linux-kernel@vger.kernel.org>
Subject: RE: [PATCH v2 2/4] tpm: Simplify locality handling
Thread-Topic: [PATCH v2 2/4] tpm: Simplify locality handling
Thread-Index: AQHXOi2MFFLqon71SkOYPqoVcMwIWKrI6e6AgACci5A=
Date:   Wed, 28 Apr 2021 07:13:28 +0000
Message-ID: <42097d7cc31c4cf495d1f8b46b3587af@infineon.com>
References: <1619394440-30646-1-git-send-email-LinoSanfilippo@gmx.de>
 <1619394440-30646-3-git-send-email-LinoSanfilippo@gmx.de>
 <YIii8RQR/Mcc7PKJ@kernel.org>
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On Mon, Apr 26, 2021 at 01:47:18AM +0200, Lino Sanfilippo wrote:
> Currently the TPM (default) locality is claimed and released for each=20
> access to the TPM registers which require a claimed locality. This=20
> results in locality claim/release combos at various code places. For=20
> interrupt handling we also need such a combo in the interrupt handler=20
> (for clearing the interrupts) which makes the locality handling even=20
> more complicated since now we also have to synchronize concurrent=20
> accesses in process and in interrupt context.
>
> Since currently the driver uses only one locality anyway, avoid the=20
> increasing complexity by claiming it once at driver startup and only=20
> releasing it at driver shutdown.
>
> Due to the simplifications the functions tpm_request_locality() and
> tpm_relinquish_locality() are not needed any more an can be removed.
>

+1
I like the idea, as it also improves performance a bit.
Peter