From mboxrd@z Thu Jan 1 00:00:00 1970 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.subspace.kernel.org (Postfix) with ESMTPS id C439130100; Tue, 3 Jun 2025 13:00:57 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.137.202.133 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1748955659; cv=none; b=c8m3+icGzDnIYmZhXIEbzzluyF4d4gr3gamGj6/pFB2W4Kxi16A5CwPfURQatHsI5EVDejor3LaP+4BNBlos0CNIpN7m5bzCHndfPveG4wAYouUDY5JvyWZiG+SMZn08td5u/6AjnTITpCgg54fHSpVadkNqrHCF72mryPVvP9w= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1748955659; c=relaxed/simple; bh=jCb8MjzKqnSSvBISyPEr68pWSxze6cYxQdDQYeMGOwc=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=iDK28Rz5h9NVXg//jqCaxfOBqosDV9CAyX7Dhns5RhtBRYxQiYh2H31a82mXkESUnTjoKvG4u2+wS1Tr6EpAUzGj3fYw3VzOL63X0+xIO7fe/PBho20t+mSHpDzxCbhjxbg8Cu5HxyciUqx0RUwn0a6huwT3QsP9zL4mN7xiXqk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=bombadil.srs.infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=IPmsxnFJ; arc=none smtp.client-ip=198.137.202.133 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=bombadil.srs.infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="IPmsxnFJ" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=k1XPNptp9fZRgF5DPHVBqQdEmjS4I5KaqBv2b545vMo=; b=IPmsxnFJvpQV/07pXtCij5n7+B dFvjHtMPi4nMCn+YxfA9D4q9Mo8YX4qbhw9zesK8Ye1oTQFfXOQZ/IA9OTm0ofT2D1sgqFw43T4hL t8XZQGHRymH3mU/lN+Upl0Igc/rCnrDLMNshOBwuZUtJ1LHLchLQtozjfj5mzVUeg8cD6mSy5Nh0p zbvkyHiVp/2iCP4XT81nCh1MtbWZzZ4rqlF4c2CZyQIU/QqowJP/EvfXW0UDpU8D3v8iVKN1pCE5A IYie6a2i83wKfvsj7leN7vjLIHruu6zzcxDvLTGGBgxgEYC3HBCEueUdJ/FNW7uw9voCx/Tgzd17j emTU48WA==; Received: from hch by bombadil.infradead.org with local (Exim 4.98.2 #2 (Red Hat Linux)) id 1uMRG1-0000000Aypb-1Zk1; Tue, 03 Jun 2025 13:00:45 +0000 Date: Tue, 3 Jun 2025 06:00:45 -0700 From: Christoph Hellwig To: wangtao Cc: sumit.semwal@linaro.org, christian.koenig@amd.com, kraxel@redhat.com, vivek.kasireddy@intel.com, viro@zeniv.linux.org.uk, brauner@kernel.org, hughd@google.com, akpm@linux-foundation.org, amir73il@gmail.com, benjamin.gaignard@collabora.com, Brian.Starkey@arm.com, jstultz@google.com, tjmercier@google.com, jack@suse.cz, baolin.wang@linux.alibaba.com, linux-media@vger.kernel.org, dri-devel@lists.freedesktop.org, linaro-mm-sig@lists.linaro.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, bintian.wang@honor.com, yipengxiang@honor.com, liulu.liu@honor.com, feng.han@honor.com Subject: Re: [PATCH v4 0/4] Implement dmabuf direct I/O via copy_file_range Message-ID: References: <20250603095245.17478-1-tao.wangtao@honor.com> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250603095245.17478-1-tao.wangtao@honor.com> X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html This is a really weird interface. No one has yet to explain why dmabuf is so special that we can't support direct I/O to it when we can support it to otherwise exotic mappings like PCI P2P ones.