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Date: Tue, 22 Sep 2026 15:20:16 +0200
From: Christoph Hellwig <hch@lst.de>
To: Pavel Begunkov <asml.silence@gmail.com>
Cc: linux-block@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-media@vger.kernel.org, dri-devel@lists.freedesktop.org,
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	Sumit Semwal <sumit.semwal@linaro.org>,
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	Keith Busch <kbusch@kernel.org>, Sagi Grimberg <sagi@grimberg.me>,
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	Mikulas Patocka <mpatocka@redhat.com>,
	Benjamin Marzinski <bmarzins@redhat.com>, dm-devel@lists.linux.dev
Subject: Re: [PATCH v6 06/13] nvme-pci: implement dma-buf backed requests
Message-ID: <20260922132016.GA30684@lst.de>
References: <cover.1789997898.git.asml.silence@gmail.com> <e80c3b1e0de004eaca6c51a2a86115ac9ed36381.1789997898.git.asml.silence@gmail.com>
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User-Agent: Mutt/1.5.17 (2007-11-01)

On Mon, Sep 21, 2026 at 02:38:50PM +0100, Pavel Begunkov wrote:
> Enable BIO_DMABUF_MAP backed requests. On registration we map the

This is now REQ_DMABUF.

Sashiko had a few comments, which I think are correct - if we use
dma_map_sg to map the data, we need to use the sync_sg APIs to
transfer ownership.  That only matters on non-coherent architectures
with MMU, but we need to get it right.

And the reset deadlock also looks plausible.