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Date:   Wed, 24 Aug 2022 00:32:53 +0100
From:   Al Viro <viro@zeniv.linux.org.uk>
To:     "Fabio M. De Francesco" <fmdefrancesco@gmail.com>
Cc:     Christoph Hellwig <hch@lst.de>, Sagi Grimberg <sagi@grimberg.me>,
        Chaitanya Kulkarni <kch@nvidia.com>,
        James Smart <james.smart@broadcom.com>,
        Ira Weiny <ira.weiny@intel.com>,
        "Venkataramanan, Anirudh" <anirudh.venkataramanan@intel.com>,
        linux-nvme@lists.infradead.org, linux-kernel@vger.kernel.org,
        Chaitanya Kulkarni <chaitanyak@nvidia.com>,
        Keith Busch <kbusch@kernel.org>
Subject: Re: [PATCH v3 1/1] nvmet-tcp: Don't kmap() pages which can't come
 from HIGHMEM
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References: <20220822142438.5954-1-fmdefrancesco@gmail.com>
 <20220822142438.5954-2-fmdefrancesco@gmail.com>
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On Mon, Aug 22, 2022 at 04:24:38PM +0200, Fabio M. De Francesco wrote:

> Therefore, replace the kmap() of sg_page(sg) with a page_address() and
> delete the "nr_mapped" field from "nvmet_tcp_cmd" and instead pass a
> local variable to iov_iter_kvec() from the call site in
> nvmet_tcp_map_pdu_iovec().

I'd suggest looking into switching to ITER_BVEC...