From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793106724; b=raMoHuk0r1xyfm43dSVH83VtIXTbsbeeRFbZjZTWlcIIiHtcti0OedTy4svm4ebci71r XM2IKu/QoZgCW07SL2AUhPIPLJ8d3FwyvZQpvQJrGIAuCOb53r2li+C7Ntsc62remB5HZ tcbPp0Gg3RxEaQUgJC3UKMv9vwKte3O+YwWN+wdbgbPDFPQvkX7uFgSqOOExOVwaqJn6Z 7yMplBTv6S5HKDfmMqtILC1kgmkqUEp3maHQMmWCy5jD5r4tZ4ilHdreIVivSD7ejjZrv bLnHz0NTISffRHp5eq7KOZnOJPyqcZS8JtmmHN951XRcWFBviPtypJfLBTBg9U3XzFQ== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793106724; h=Received:DKIM-Signature:Date:From:To:Cc:Subject:Message-ID: References:MIME-Version:Content-Type:Content-Disposition:In-Reply-To; bh=2MMXzSmivNiYm7xgnDiu+/n7gX5wknAWsvpVij8nk9k=; b=lAHU3ValCwT9R9l0QtuwsKs5O38clUhmXtnzCkCntMTwwIgMXPTqi2KydYirEByUz7Xl GdOJu0rjAhJLeY2L+OspW3e2De5qzNxswmFlsmYTzWL8mltMR3lEHoqXuLIDHiXG9NsR7 2d0EDYqZcjuvQgir+7z59akfxjw8ZmwKAvV4Z9JKwLkwV9ZUG5G5YzjAR1nKouTFLx943 4b/2AlucQXXT1oLeasKETY8uxBgmRXiihNgCN6ogGCss3dHnonuxkb1Em5vOMSHOUKdwG 7yyiqQEHj4aYiNjdaY6fInXOjRuQIQvFb/3a5qUEzoDloTdra5kUParj94waB1I/9Eg== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=m1KbTfFL; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id DA931606A31A; Tue, 27 Oct 2026 13:12:03 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=m1KbTfFL Received: by smtp.kernel.org (Postfix) with ESMTPSA id DB63E1F01825; Tue, 27 Oct 2026 13:12:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1793106723; bh=2MMXzSmivNiYm7xgnDiu+/n7gX5wknAWsvpVij8nk9k=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=m1KbTfFLRc6URg44I7EPyv0n3lBQykW7ConS/2FmF//DD57D5lAAvGm7YoCwnlX6a NQpq2Lv9L0WXiUDPKew+8VQzU660fmYwkQyBoKJbgvEb6eObZnAAWqqV+5Eq4U7i0P xUxp4GsKmpTs9AyY1CUbZM/JFyZrwvqvkPYtIZf4= Date: Tue, 27 Oct 2026 14:12:02 +0100 From: Greg Kroah-Hartman To: Jens Axboe Cc: Li Wang , Arnd Bergmann , Sumit Semwal , Christian =?iso-8859-1?Q?K=F6nig?= , Pavel Begunkov , linux-media@vger.kernel.org, dri-devel@lists.freedesktop.org, linaro-mm-sig@lists.linaro.org, io-uring@vger.kernel.org, linux-kernel@vger.kernel.org, Mengmeng Zhao Subject: Re: [RFC PATCH v2 1/1] misc: fgds: introduce GPU-File direct I/O via dma-buf Message-ID: <2026102734-booting-playtime-557d@gregkh> References: <20260908131545.105987-1-liwang@kylinos.cn> <20261027090853.30099-1-liwang@kylinos.cn> <20261027090853.30099-2-liwang@kylinos.cn> X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Tue, Oct 27, 2026 at 07:03:29AM -0600, Jens Axboe wrote: > On 10/27/26 3:08 AM, Li Wang wrote: > > From: Mengmeng Zhao > > > > This patch introduces a driver that allows moving data between a GPU > > dma-buf and a regular file on NVME without staging it through the page > > cache. Userspace registers the GPU dma-buf with the device, then issues > > read and write requests via the device's ioctls. Each transfer is direct > > I/O: an ITER_DMABUF_MAP iterator is passed to the file's read_iter or > > write_iter, and the filesystem's iomap path submits REQ_DMABUF bios that > > already carry the dma addresses. > > > > Signed-off-by: Mengmeng Zhao > > Signed-off-by: Li Wang > > --- > > .../userspace-api/ioctl/ioctl-number.rst | 2 + > > drivers/dma-buf/dma-buf-io.c | 3 + > > drivers/misc/Kconfig | 16 + > > drivers/misc/Makefile | 1 + > > drivers/misc/fgds.c | 506 ++++++++++++++++++ > > fs/iomap/buffered-io.c | 11 + > > fs/iomap/direct-io.c | 23 +- > > fs/xfs/xfs_file.c | 4 + > > include/linux/iov_iter.h | 4 + > > include/uapi/linux/fgds.h | 124 +++++ > > lib/iov_iter.c | 1 + > > mm/filemap.c | 22 +- > > 12 files changed, 713 insertions(+), 4 deletions(-) > > create mode 100644 drivers/misc/fgds.c > > create mode 100644 include/uapi/linux/fgds.h > > What's the point of this, when you can just use io_uring to do > the same?! Agreed, I thought that the summary of the last round of reviews was "this isn't needed at all". Li, what changed from that? thanks, greg k-h