From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailout2.samsung.com (mailout2.samsung.com [203.254.224.25]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id DF70D344037 for ; Mon, 9 Feb 2026 10:04:53 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=203.254.224.25 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770631494; cv=none; b=DT6XDacD44FqGeHBMmp+IMfSWrKHN6IpOpg2Ggl9rGMUpCnZD+O2dgviaqpf/KeRz8sy+DHIW+FeTnUi9i4WZ3+knMo3D0azDpfdQu10T1W2RFiKpAzbZzzeGIqa8D2KVxJoahqFPdi++OmMQj8dBOQ2qyyPbdLmuvBg4oOPM+A= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770631494; c=relaxed/simple; bh=cFiRXRE0SoHVqgNVMPo+ew/Ov1wphdgz+R6dS43ENoY=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:From:In-Reply-To: Content-Type:References; b=DZYb14Zi0xY+TE3PUtdGSDyQpHN8YWbMsubcgDtwOLapwUMC/SSpPElReyJjAIexqv7jTw5mpJpTAbrl8amG+EynKb74SIG0/Glt3QqDRX7r8xNPaHXDCS7GCgt+myN87LDI9/DRb5wKUZt5ZGqScC0VC4M29AFVwepCq3Z2S14= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=samsung.com; spf=pass smtp.mailfrom=samsung.com; dkim=pass (1024-bit key) header.d=samsung.com header.i=@samsung.com header.b=M0PU4SJA; arc=none smtp.client-ip=203.254.224.25 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=samsung.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=samsung.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=samsung.com header.i=@samsung.com header.b="M0PU4SJA" Received: from epcas5p4.samsung.com (unknown [182.195.41.42]) by mailout2.samsung.com (KnoxPortal) with ESMTP id 20260209100451epoutp0238943c4866a2858505224ef72a81751b~Si-XXAIFG0885708857epoutp02h for ; Mon, 9 Feb 2026 10:04:51 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 mailout2.samsung.com 20260209100451epoutp0238943c4866a2858505224ef72a81751b~Si-XXAIFG0885708857epoutp02h DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=samsung.com; s=mail20170921; t=1770631491; bh=wt+xzp1ENYsfh++JT8pJEqjJy6IREEFFHEG8QaQpp2M=; h=Date:Subject:To:Cc:From:In-Reply-To:References:From; b=M0PU4SJAclY0eXdEEkxL7W3l4RdvfkAlxlzdKax8lupZZA9Cl/jrx3j6ZOZP25yX+ aEpRs8klxsOfPDog79GlTXng/MXN3vmtQU1Iyp+6hldb0cK5uuJbrbTaNyAdn1TzPn R54qbHwrhOful2d1/CJ51zzsOdS1N40jgdgoaZGY= Received: from epsnrtp01.localdomain (unknown [182.195.42.153]) by epcas5p1.samsung.com (KnoxPortal) with ESMTPS id 20260209100451epcas5p10e8d99b66259e22b08fab2a6a4df98a8~Si-W6nlVY0968409684epcas5p1Q; Mon, 9 Feb 2026 10:04:51 +0000 (GMT) Received: from epcas5p4.samsung.com (unknown [182.195.38.91]) by epsnrtp01.localdomain (Postfix) with ESMTP id 4f8gKY6xgMz6B9mB; Mon, 9 Feb 2026 10:04:49 +0000 (GMT) Received: from epsmtip2.samsung.com (unknown [182.195.34.31]) by epcas5p1.samsung.com (KnoxPortal) with ESMTPA id 20260209100448epcas5p11e31b66680677cd4399fd0efca35e6fe~Si-UuYSWS0968909689epcas5p1N; Mon, 9 Feb 2026 10:04:48 +0000 (GMT) Received: from [107.122.11.51] (unknown [107.122.11.51]) by epsmtip2.samsung.com (KnoxPortal) with ESMTPA id 20260209100444epsmtip2e68e1b03792622abf5a5c487565e1186~Si-Q3OchA2836828368epsmtip2M; Mon, 9 Feb 2026 10:04:44 +0000 (GMT) Message-ID: <0ddc5a14-26c3-4912-96a0-d619ca0fb36c@samsung.com> Date: Mon, 9 Feb 2026 15:34:43 +0530 Precedence: bulk X-Mailing-List: io-uring@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [LSF/MM/BPF TOPIC] dmabuf backed read/write To: Pavel Begunkov , linux-block@vger.kernel.org Cc: io-uring , "linux-nvme@lists.infradead.org" , =?UTF-8?Q?Christian_K=C3=B6nig?= , Christoph Hellwig , Anuj Gupta , Nitesh Shetty , "lsf-pc@lists.linux-foundation.org" Content-Language: en-US From: Kanchan Joshi In-Reply-To: <4796d2f7-5300-4884-bd2e-3fcc7fdd7cea@gmail.com> Content-Transfer-Encoding: 7bit X-CMS-MailID: 20260209100448epcas5p11e31b66680677cd4399fd0efca35e6fe X-Msg-Generator: CA Content-Type: text/plain; charset="utf-8" CMS-TYPE: 105P cpgsPolicy: CPGSC10-542,Y X-CFilter-Loop: Reflected X-CMS-RootMailID: 20260203143112epcas5p4eea9225d9378dad9151e1b843c0522ce References: <4796d2f7-5300-4884-bd2e-3fcc7fdd7cea@gmail.com> On 2/3/2026 7:59 PM, Pavel Begunkov wrote: > Good day everyone, > > dma-buf is a powerful abstraction for managing buffers and DMA mappings, > and there is growing interest in extending it to the read/write path to > enable device-to-device transfers without bouncing data through system > memory. I was encouraged to submit it to LSF/MM/BPF as that might be > useful to mull over details and what capabilities and features people > may need. Guilty as charged, I'm interested in the topic. Thanks for posting. We've had several attempts to move the DMA mapping cost out of the fast path; hopefully, this will be the final one.