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Date: Wed, 7 Jan 2026 17:01:51 +0100
From: Christoph Hellwig <hch@lst.de>
To: Christian =?iso-8859-1?Q?K=F6nig?= <christian.koenig@amd.com>
Cc: Ming Lei <ming.lei@redhat.com>, Christoph Hellwig <hch@lst.de>,
	Pavel Begunkov <asml.silence@gmail.com>,
	linux-block@vger.kernel.org, io-uring@vger.kernel.org,
	Vishal Verma <vishal1.verma@intel.com>, tushar.gohad@intel.com,
	Keith Busch <kbusch@kernel.org>, Jens Axboe <axboe@kernel.dk>,
	Sagi Grimberg <sagi@grimberg.me>,
	Alexander Viro <viro@zeniv.linux.org.uk>,
	Christian Brauner <brauner@kernel.org>,
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	linux-fsdevel@vger.kernel.org, linux-media@vger.kernel.org,
	dri-devel@lists.freedesktop.org, linaro-mm-sig@lists.linaro.org
Subject: Re: [RFC v2 01/11] file: add callback for pre-mapping dmabuf
Message-ID: <20260107160151.GA21887@lst.de>
References: <cover.1763725387.git.asml.silence@gmail.com> <74d689540fa200fe37f1a930165357a92fe9e68c.1763725387.git.asml.silence@gmail.com> <7b2017f4-02a3-482a-a173-bb16b895c0cb@amd.com> <20251204110709.GA22971@lst.de> <0571ca61-7b17-4167-83eb-4269bd0459fe@amd.com> <20251204131025.GA26860@lst.de> <aVnFnzRYWC_Y5zHg@fedora> <754b4cc9-20ab-4d87-85bf-eb56be058856@amd.com>
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On Wed, Jan 07, 2026 at 04:56:05PM +0100, Christian König wrote:
> > But I am wondering why not make it as one subsystem interface, such as nvme
> > ioctl, then the whole implementation can be simplified a lot. It is reasonable
> > because subsystem is exactly the side for consuming/importing the dma-buf.
> 
> Yeah that it might be better if it's more nvme specific came to me as well.

The feature is in no way nvme specific.  nvme is just the initial
underlying driver.  It makes total sense to support this for any high
performance block device, and to pass it through file systems.