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 65B26CD4F54 for ; Tue, 19 May 2026 06:57:05 +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-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=FqC/pq2ruIeDK/7zUEWdRi+U7XrUn4PcVEGHi+HaQw4=; b=si0t2h9J+DW0BmM3CXw8rwjiQg 2XjxSy9iSXJWOGHbYVJk6xqvMdKaGvSoT/kO+xOacdEcKjRO1p3c2kxhm0mJo5r9zJOj5ChPC3k0W 7Ks1fK60l6ndnHjfU3G2vR/ycomIzrxWdNQZkVWEsoj9wc8x0UH8Hk9yc+rBK64GV1Vcmf/v8wQTN uS94papvMUirqEnDNs4c1SFRh5ikput3l3FC/KMAWCFrs+5b3BguaRXcWrFeR5uvcyCYnnaJfLLYz VrKmh/ti6+edxeC5TnAm2sWz/BUeyCHoKlK+YR2TSOWCPbl1sR6ywED2Eyiqg+Nvzn0qp9UZahCED F48klHrw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1wPENz-00000000QF3-3bk3; Tue, 19 May 2026 06:57:03 +0000 Received: from verein.lst.de ([213.95.11.211]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1wPENx-00000000QEA-1m51 for linux-nvme@lists.infradead.org; Tue, 19 May 2026 06:57:02 +0000 Received: by verein.lst.de (Postfix, from userid 2407) id F393168AFE; Tue, 19 May 2026 08:56:53 +0200 (CEST) Date: Tue, 19 May 2026 08:56:53 +0200 From: Christoph Hellwig To: Pavel Begunkov Cc: Christoph Hellwig , Jens Axboe , Keith Busch , Sagi Grimberg , Alexander Viro , Christian Brauner , Andrew Morton , Sumit Semwal , Christian =?iso-8859-1?Q?K=F6nig?= , linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, linux-nvme@lists.infradead.org, linux-fsdevel@vger.kernel.org, io-uring@vger.kernel.org, linux-media@vger.kernel.org, dri-devel@lists.freedesktop.org, linaro-mm-sig@lists.linaro.org, Nitesh Shetty , Kanchan Joshi , Anuj Gupta , Tushar Gohad , William Power , Phil Cayton , Jason Gunthorpe Subject: Re: [PATCH v3 05/10] lib: add dmabuf token infrastructure Message-ID: <20260519065653.GB8173@lst.de> References: <20260513082431.GA6461@lst.de> <20260518125326.GA5754@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.17 (2007-11-01) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260518_235701_605697_712B418A X-CRM114-Status: GOOD ( 23.33 ) 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 Mon, May 18, 2026 at 03:23:53PM +0100, Pavel Begunkov wrote: > To be fair, it's not that dma-buf specific. This lib/ code only > does some resv locking, fence waiting and queuing fences, But all the dma resv/fence stuff is pretty tied into the dma-buf ecosystem. I don't think it would really apply to something not doing DMA at all. > otherwise > all the attaching is done by the driver behind callbacks. Switching > it to some memfd could be pretty simple. But The main thing it'd > need to share is iterator handling like forwarding in the block > layer, and it should be fine as it's already passed as a completely > opaque object with no knowledge about pages / dma / etc. for the > middle layers. But none of that really sits in the current lib/ code anyway? >> lib/ is most certainly the wrong place for something that absolutely >> is not library functionality but directly interacts with a few >> subsystems. > > It only interacts with dma-buf, and even for dma-buf attachments > are created by the driver. Block, nvme, io_uring are users, either > using the helpers or implementing callbacks. > > Ok. Let's assume for the argument's sake it's not dma-buf > specific, if not lib/, where would you put it? I was also > assuming that dma-buf being under drivers/ is rather a relic > of the past rather than the desired location, hmm? drivers/dma-buf is a pretty natural place for it, I could not thing where else you'd place dma-buffers. I'm not sure how hmm has anything to do with it. > > > -- > Pavel Begunkov ---end quoted text---