From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=91.218.175.41 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794553725; b=WUC5VQ/1nHqMmm8Ifurjcgx6y2SFrJ+oEYE9SYx3ocrJVv10+k4lBQRXbMuoW/yYVhrg lIkoJcr3DsZSKajWxBabCut4wQSOYV1iPhnxaKIQjdokvV9eYPNXr6x6V3wKKaCqCUgaS DIkUBZBDXdc8TtCyUQ0VxWuddGHXwtwasmW3b4hxZd41FSwsTYE03IcAqfThpkUqy6QB4 SLMXuIxizQrFsBZLOi0HLC2/PzboU58pk3z3IBaIb4+kT6EJ4ZJb6JI1m66vdkG6IkZZ+ ZjnGElhKvazls9XGvUDfGKayM1FIKQTnXZ3vy4uJ3VAbiD6/k1V71yb7CcnqiAqjzNg== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794553725; h=DMARC-Filter:X-Envelope-To:DKIM-Signature:X-Envelope-To:Received: X-Mizu-Trace-ID:X-Migadu-Flow:From:To:Cc:Subject:Date:Message-ID: X-Mailer:In-Reply-To:References:MIME-Version: Content-Transfer-Encoding; bh=XYDjtxaf0lVfH8OsewVAiM2b9d3+k+o70NuMLB1ofvM=; b=DLyGnfsNfJq2yL4wgzMufaziYHmSe4UPwHz6vwA7MYoWXI9uGFi3lcwAyjVWiGkoLRez wr+r5V9M85goZKF+Mjj0VrMWcrGeFA0J3CLABYjb88bfwpXw1PbjcrRfNCgavaLyVBQDz LyhWiajgxSjY4ssauANVsXnTAmixjaIQaBo4VJIDTrOpj3I1ShZAgm0NOiBadvC6Xaqht /8LooovRBHUpKxADnq6MMwIxdfrspGIjkx7oOaNBH5V0VNVoeyAkLG+Umju99++93q1TH qJ9/ARRgIjVWPineQDCpc0S6Tr8/Nq10CxRz6vC2sJd32gftuXByJ4s47KP3CumRz/A== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass header.d=linux.dev header.i=@linux.dev header.a=rsa-sha256 header.s=key1 header.b="D/kJqV7U"; arc=none smtp.remote-ip=91.218.175.41 Received: from mta0.migadu.com (out-41.mta0.migadu.com [91.218.175.41]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5F7A9606A8B9 for ; Fri, 13 Nov 2026 07:08:44 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org 5F7A9606A8B9 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev 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=D/kJqV7U X-Envelope-To: linux-doc@vger.kernel.org DKIM-Signature: a=rsa-sha256; bh=CjYG6lLCB1BYJrLcL7BR63FCu2vQ5oxiLdcSaVMwGGM=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1794553722; v=1; x=1795158522; b=D/kJqV7UQLV4kqW3cK/Wgu7CpSKD4Itj3W/PwPZ6JnlXfORvwpwwHWER7A/3RZ5fFZf0jRsk uolfbh5zwcaM5SDlpzrZKMndoJH6ubVZsg+nhwga8JW/08XSKdcRP2l4Tct40ySKJBhbWIzqIhY /xmbysyUIU1KIdQaamOFWA+Q= X-Envelope-To: linux-doc@vger.kernel.org Received: by smtp.migadu.com with ESMTPS id 0eecb32ce231a7d3; Fri, 13 Nov 2026 07:08:41 +0000 X-Mizu-Trace-ID: 0eecb32ce231a7d3 X-Migadu-Flow: FLOW_OUT From: Mengmeng Zhao To: Christoph Hellwig , Anuj Gupta , Nitesh Shetty , Jens Axboe , Sumit Semwal , christian.koenig@amd.com, Philipp Stanner , Dan Williams , Matthew Wilcox , Jan Kara , Alexander Viro , Christian Brauner , tytso@mit.edu, Andreas Dilger , Baokun Li , Ojaswin Mujoo , "Ritesh Harjani (IBM)" , Zhang Yi , asml.silence@gmail.com, Jonathan Corbet , Shuah Khan , Randy Dunlap Cc: 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-doc@vger.kernel.org, linux-media@vger.kernel.org, dri-devel@lists.freedesktop.org, linaro-mm-sig@lists.linaro.org, Li Wang , Mengmeng Zhao Subject: [RFC PATCH v2 7/8] dax: refuse dma-buf iterators in dax_iomap_rw() Date: Fri, 13 Nov 2026 15:06:20 +0800 Message-ID: <20261113070621.273953-8-mengmeng.zhao@linux.dev> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20261113070621.273953-1-mengmeng.zhao@linux.dev> References: <20261113070621.273953-1-mengmeng.zhao@linux.dev> X-Mailing-List: linux-doc@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Mengmeng Zhao DAX copies data through the CPU, so a dma-buf iterator has no meaning in the DAX I/O path and must be refused. A DAX inode does not get FMODE_CAN_DMABUF_IO at open time, but DAX can be enabled later, so check per I/O. Signed-off-by: Mengmeng Zhao Signed-off-by: Li Wang --- fs/dax.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/fs/dax.c b/fs/dax.c index 94ba41273347..84d24db5ed35 100644 --- a/fs/dax.c +++ b/fs/dax.c @@ -1752,6 +1752,10 @@ dax_iomap_rw(struct kiocb *iocb, struct iov_iter *iter, if (!iomi.len) return 0; + /* a dma-buf iterator has no CPU-visible pages to copy through */ + if (iov_iter_is_dmabuf_map(iter)) + return -EOPNOTSUPP; + if (iov_iter_rw(iter) == WRITE) { lockdep_assert_held_write(&iomi.inode->i_rwsem); iomi.flags |= IOMAP_WRITE; -- 2.43.0