From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 777D8606A331 for ; Mon, 9 Nov 2026 02:54:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=linux.dev header.i=@linux.dev header.a=rsa-sha256 header.s=key1 header.b=tN54d4fE Received: by kanga.kvack.org (Postfix) id 6A39E6B05B3; Sun, 8 Nov 2026 21:54:33 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 654C46B05B4; Sun, 8 Nov 2026 21:54:33 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 56A156B05B5; Sun, 8 Nov 2026 21:54:33 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id 3211D6B05B3 for ; Sun, 8 Nov 2026 21:54:33 -0500 (EST) Received: from smtpin28.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay09.hostedemail.com (Postfix) with ESMTP id 9BE8A80279 for ; Mon, 9 Nov 2026 02:54:32 +0000 (UTC) X-FDA: 85414062384.28.C4588A8 Received: from mta1.migadu.com (out-137.mta1.migadu.com [95.215.58.137]) by imf16.hostedemail.com (Postfix) with ESMTP id 932FF180002 for ; Mon, 9 Nov 2026 02:54:30 +0000 (UTC) Authentication-Results: imf16.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=tN54d4fE; spf=pass (imf16.hostedemail.com: domain of mengmeng.zhao@linux.dev designates 95.215.58.137 as permitted sender) smtp.mailfrom=mengmeng.zhao@linux.dev; dmarc=pass (policy=none) header.from=linux.dev ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1794192871; b=O3DVRg9AC/FRBzAWjfuLchWlwo02EjE1CvQRkudUfKe55NB06gCfx3qEDGlrruYCcDFaYQ hPIAvBs/Pfh35N/WxdDaUfmjuAPR824sliMtqrYCkHgnbcrKxKmrxVDtiX6c+XskY1vAkx mS5AgBhMSCQptzTzlxF00syiIr+SzhU= ARC-Authentication-Results: i=1; imf16.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=tN54d4fE; spf=pass (imf16.hostedemail.com: domain of mengmeng.zhao@linux.dev designates 95.215.58.137 as permitted sender) smtp.mailfrom=mengmeng.zhao@linux.dev; dmarc=pass (policy=none) header.from=linux.dev ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1794192871; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=eoxX5hhnrVdnCsiEYxw4rUS1B0+rsEN339m2Nai3htg=; b=QzbMpGVHgmn09mGSSE8m2nLIrJmeL+l+qA236Yt3VMZq8yDfXe8cTzjdtDWMI79NEvOx2h o+nN+jdQshPlN/qmo6ytrapfVNXZj2FDw2U/fkloupPttnt2lga8e3DbRl6zePsmYhuF2L cf/c36YvMFMWcajXZBf0Xr7SIRwWPuw= X-Envelope-To: linux-mm@kvack.org DKIM-Signature: a=rsa-sha256; bh=8GZA7yXccoOl25ncF5WoFStP/OWge7+wGkdg+7Q22+4=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1794192869; v=1; x=1794797669; b=tN54d4fELbTw1iziAe++lO07fZ5SAh4ue1naK2/9LPEFWsB9OLEZ7IIGwvMwJvNf7ENjDX9l QF+x5znsrYZqBLXzHYLOEerlPhB46/CjWVcI55sfgyCGnVuArQb6b6zkWJJxnh0Q7RS+EamCd8D JxPzlZh1L1SF3JmB2gcgkYPc= X-Envelope-To: linux-mm@kvack.org Received: by smtp.migadu.com with ESMTPS id 197dc3b85a73d5c0; Mon, 09 Nov 2026 02:54:28 +0000 X-Mizu-Trace-ID: 197dc3b85a73d5c0 X-Migadu-Flow: FLOW_OUT Message-ID: Date: Mon, 9 Nov 2026 10:54:14 +0800 X-Archived-By: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [RFC 2/6] mm/filemap: refuse dmabuf iterators in the generic read/write copy paths To: Christoph Hellwig Cc: Jens Axboe , Dan Williams , Matthew Wilcox , Jan Kara , Alexander Viro , Christian Brauner , tytso@mit.edu, Andreas Dilger , Baokun Li , Ojaswin Mujoo , "Ritesh Harjani (IBM)" , Zhang Yi , "Darrick J. Wong" , Andrew Morton , asml.silence@gmail.com, Anuj Gupta , linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, nvdimm@lists.linux.dev, linux-ext4@vger.kernel.org, linux-xfs@vger.kernel.org, linux-mm@kvack.org, Li Wang References: <20261105065847.196540-1-mengmeng.zhao@linux.dev> <20261105065847.196540-3-mengmeng.zhao@linux.dev> <20261106104205.GB5668@lst.de> From: Mengmeng Zhao In-Reply-To: <20261106104205.GB5668@lst.de> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Stat-Signature: 6y714fzhrwrawyfwezrwfuzif6jp4j6c X-Rspam-User: X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 932FF180002 X-Spam-Status: No, score=-7.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_PASS,SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=4.0.1 X-HE-Tag: 1794192870-496789 X-HE-Meta: U2FsdGVkX1/nlT48lDcNeM1oSWU++aLxgp5PRvuALMjOG7BnmcdUXU5TCbSVSTHPW9cP1dJjYnZUNUcbM33kLiO2h3Ae7Pv1RwbDOSfTORmbLfVUGz11jfqGX7fXWuD5e6IhCD+VaFcBsVASxNh6IAeiBOL33tRgU3azZyT1dMmcSNvo5L2tYQWH5o7fY1T/VXTcBIFO7mLDYOkOkQLCH6cX2nbpif+UC+q4GhXh0XOQEFilEQJkoq2XUF5vpMO/2STIt+z+jKUxvNPMdD3ixTkGAKlhjmPlIPh4gNTdmDE0ATU1Wvt9EhOl5rBxsdPejt5iP37sWF12y3yXg2CDe9NsxhzRRmBoCLjTwqpEYMBcJ6vSNEVlFqSrMl+3YTbY8ZHawDIchKR1EPPpU5uvtunS7avvv3xjF1G1bYVQTGfXpQoYdROBK+9QU9u8srt3v9U4wWApSQq0dPLrEwaAa1ha/y0m4UgYupVSwQLyFrSJCcVA08tHxsG3RupfB9iuJcUggiMQ2z9wKhJIs1YNXjcQDn2f376L+AvMvldPcQig5O0XMT1SuyGkNwRmc+XKkigNax/ZbZLZ+UHlN4BGBmqqmlFl95OrX2lWDskSQ59qB6YVS+7d9TZl6FS3pHU3zbcIBfCBxMKb/rjgC/lYg+JA0oZ1CYhe6XV7E4IfoHl407lNXYzPdClg2fEdpDSqDnw8wspiO+IjQMPUcGRGeG12x4J8EqjiVSX7vI4XDdIG4Z0K/OAtunxYqBJGE7Hx7AsExiljwd7mSScU0h/C0sBlsmQklQ0hzuGpZmSqXVA/HSBojcS1lLjsxhmyYiVzgBgTSAlUivXUayZqmEMeiVLa4s2L0rEb1gA0A/NH78JfzqlLTHT6GYKiUfc3WqSNGkVPzEsaMNdpp/wHzPzNBljLYVepniiJqcP+BQ417EXjAaIRBQLDffkP8moOQtoKjsBpzV4OKwEoFtVNChY ldhWVA87 VjbvvZYh69A2HBRZoe1cqxxCNJGTfq6TY232XPcmqL4NHaU2hYrc4NW6n8If5a2XITLcVByYxNtGhBbe0ZjdW9sNvvCcvN/mRn9QbsFxHBuTdMF6f+KpvvvCcYG6REIQ43U9xySAOpxP5xkEcqmufzLflxPUHPbhG0LJ8GxnkUTh8PQWPG8SoSbi0qlaYvifL0x5NdIa1Pj/zEmotYVGZ3RcU/XqL1I2DsSu6mfNoZUBw6Cu3pDTaQNV103dgPw4CLcQy4R7QL5KmIrmfXYn6UHYV+ANGZzmnRlSyI0fTsA/teFGKgor4dQwNGYYhYrkD4I1it3ZNsYctGyMA7wsBiIQIvUILk6GfqCYQ Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 On 11/6/26 18:42, Christoph Hellwig wrote: > On Thu, Nov 05, 2026 at 02:58:43PM +0800, Mengmeng Zhao wrote: >> From: Mengmeng Zhao >> >> The generic copy helpers cannot touch device memory. > > Which generic copy helpers? This doesn't seem to touch copy_file_range > at all. > Sorry for the inaccuracy, it refers to the buffered io patch in generic_file_read_iter() and __generic_file_write_uter(). >> Refuse a >> dmabuf iterator in generic_perform_write() and the filemap_read() >> fallback while keeping any direct-I/O progress, and report a busy >> folio from generic_file_direct_write() as -EAGAIN instead of asking >> for the buffered fallback such an iterator cannot take. > > I suspect the fallback code in the callers might be a better stop > for this. > Ok, I will put it in the callers side.