From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 04653D1F9BC for ; Thu, 4 Dec 2025 11:07:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To: Content-Transfer-Encoding:Content-Type:MIME-Version:References:Message-ID: Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=Sb2xGsKMUQpHqTU6d6wbwOW9imPiiQCMhOD+8gvlZqM=; b=U8EmYBtyC61BadGjaz5c1TPUwe TtdXZngYtmn9MVsRqFQl+tVzcLyM9zvGpaqwqpm9v4xOSsBYeHLKGwyRcVNPBoj8S1EFqJ23BhR2B t/Icplsd8iw5U49kzgJUH+s65V3TV0A/xqEVqHSeYC0NfE5MDpsC9BaxflF/nEnmBAe3/Q3fPaCq7 7RUeKvL6jJQtrHiYuoxt7DdjaUNjjBIiav8luxIXCYDmxVr4e5kawEbD00AQ7S8K2iy+ILxKh25Cx /MOAieeowmYZLs2XbbT/QjMapwLaTSsd1izYCPxlen93wqGfBYRDvti+lGsNrP7MwB+TUlsQ4WWnx IMGtozQA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vR7B8-00000007tez-1Ate; Thu, 04 Dec 2025 11:07:18 +0000 Received: from verein.lst.de ([213.95.11.211]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1vR7B6-00000007tea-2Jww for linux-nvme@lists.infradead.org; Thu, 04 Dec 2025 11:07:17 +0000 Received: by verein.lst.de (Postfix, from userid 2407) id A036F68B05; Thu, 4 Dec 2025 12:07:09 +0100 (CET) Date: Thu, 4 Dec 2025 12:07:09 +0100 From: Christoph Hellwig To: Christian =?iso-8859-1?Q?K=F6nig?= Cc: Pavel Begunkov , linux-block@vger.kernel.org, io-uring@vger.kernel.org, Vishal Verma , tushar.gohad@intel.com, Keith Busch , Jens Axboe , Christoph Hellwig , Sagi Grimberg , Alexander Viro , Christian Brauner , Andrew Morton , Sumit Semwal , linux-kernel@vger.kernel.org, linux-nvme@lists.infradead.org, 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: <20251204110709.GA22971@lst.de> References: <74d689540fa200fe37f1a930165357a92fe9e68c.1763725387.git.asml.silence@gmail.com> <7b2017f4-02a3-482a-a173-bb16b895c0cb@amd.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <7b2017f4-02a3-482a-a173-bb16b895c0cb@amd.com> User-Agent: Mutt/1.5.17 (2007-11-01) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20251204_030716_756009_599FE2BA X-CRM114-Status: GOOD ( 15.35 ) X-BeenThere: linux-nvme@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "Linux-nvme" Errors-To: linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org On Thu, Dec 04, 2025 at 11:46:45AM +0100, Christian König wrote: > On 11/23/25 23:51, Pavel Begunkov wrote: > > Add a file callback that maps a dmabuf for the given file and returns > > an opaque token of type struct dma_token representing the mapping. > > I'm really scratching my head what you mean with that? > > And why the heck would we need to pass a DMA-buf to a struct file? I find the naming pretty confusing a well. But what this does is to tell the file system/driver that it should expect a future read_iter/write_iter operation that takes data from / puts data into the dmabuf passed to this operation.