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Date:   Mon, 7 Oct 2019 16:43:23 -0700
From:   Jerry Snitselaar <jsnitsel@redhat.com>
To:     James Bottomley <jejb@linux.ibm.com>
Cc:     Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>,
        linux-integrity@vger.kernel.org, Peter Huewe <peterhuewe@gmx.de>,
        Jason Gunthorpe <jgg@ziepe.ca>, Arnd Bergmann <arnd@arndb.de>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        open list <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v3 1/2] tpm: Use GFP_KERNEL for allocating struct tpm_buf
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Reply-To: Jerry Snitselaar <jsnitsel@redhat.com>
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        Jason Gunthorpe <jgg@ziepe.ca>, Arnd Bergmann <arnd@arndb.de>,
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On Mon Oct 07 19, James Bottomley wrote:
>From: James Bottomley <James.Bottomley@HansenPartnership.com>
>Subject: [PATCH] tpm: use GFP kernel for tpm_buf allocations
>
>The current code uses GFP_HIGHMEM, which is wrong because GFP_HIGHMEM
>(on 32 bit systems) is memory ordinarily inaccessible to the kernel
>and should only be used for allocations affecting userspace.  In order
>to make highmem visible to the kernel on 32 bit it has to be kmapped,
>which consumes valuable entries in the kmap region.  Since the tpm_buf
>is only ever used in the kernel, switch to using a GFP_KERNEL
>allocation so as not to waste kmap space on 32 bits.
>
>Fixes: a74f8b36352e (tpm: introduce tpm_buf)
>Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
>---

Reviewed-by: Jerry Snitselaar <jsnitsel@redhat.com>