From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794554819; b=hUPsP4DAsKFzAKwqERK3F8CQG28n27aVHONlmqGlkahA1dI69yFGpG8KNh3sn92uRQ/Y 7waeJN39KmlosIa7fDjKW978uUJZ3B/IHlNcy+o1OQtPrBHA0cSAZ7IazMwXYSSotZEqH ASSyO8iIYwXbH8iXg+UPeOgo8PI2o82xfkBwv9rv56N6sE4OAOKyp6vm31YrEzDzcMr3m tCJdGpBnjoQcd2AWxhk8JlYCYJGIXkQSyW+Kj+8876p9X57fqYryR3zdryTjbPYZc1y/7 H/6hkhJ5ccqpKDjLoBy/C0gqHlxl2EMn6Wu+gtce8bJwxWB6UaCLmW0xuSwIDLnEwdw== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794554819; h=Received:DKIM-Signature:Message-ID:From:Subject:Reply-To:To:Cc: In-Reply-To:References:Content-Type:Content-Transfer-Encoding:Date; bh=DYHniJB35d/WdQJtZVNf8qfDAJQcAmjOcwxAFZrGwPQ=; b=VsGNVaq8gmGTry0qkj7kYtgjz9d+dTDjxPJ3f08/2Ll/BOdpUp1cjbj4R4dsiCiDZhNm B8YkS9jwlE75Ce/DDVwk1R7wUYhVChjmLNRmRxEGkh4afcgWcTVi1yf5IUMM97APiRL7r MAWq57mPQSBkp5bKUSc1s+Z/399Jcw1hW7jlmDZhTCrFX1u7e8GUiAcGsKygJJo7fWkqe 1hmpLp+qpU88cElcS1DpLEf55bBQ0GKFhSBx6owaot+1Uno9UiMYItwdhm6yQf7JRTcts of4kJgSKIMRU30seeAFU5qAvRD++7FzjUgAyooogx92chBSxPNPktCWuMFxpCYNO2LA== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=BSKhSlXZ; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 465E0606A323 for ; Fri, 13 Nov 2026 07:26:59 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=BSKhSlXZ Received: by smtp.kernel.org (Postfix) with ESMTPSA id BC3D31F000C4; Fri, 13 Nov 2026 07:26:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794554818; bh=DYHniJB35d/WdQJtZVNf8qfDAJQcAmjOcwxAFZrGwPQ=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=BSKhSlXZFJ+mntgryqot32Ymz6nPmHR3dUgi+Qw0vW1AQ5vVYa6dxUoAtGzZTEmpE kxqjny7FlsiDpZ5+k0tpBF57XFij/Fn95ZeHWBfPw0v7YBJgVJwOpOL4L1z1VKjJNI W4+FYkg13umLf1iRQ1igl4Wl6Yl4aEzWlUljez8A+4e7z+Yk84/GuGsPTrO5Ay0Hbf LgXQ7ZEZTfPUpCHjV2nMJvutZcNUoFrgl5Os0UmeTkM0u9IYFDYJwLmQS09gd/awwb 49QSlR1Hl16YYSzhNmk8i38Z3d4JEA0IerCb212TFH3KiUa5FXhGABs9Os/WFc4N15 1kJ3jCNjzTVWw== Message-ID: From: sashiko-bot@kernel.org Subject: Re: [RFC PATCH v2 8/8] ext4: support dma-buf registered buffers for direct I/O Reply-To: sashiko-reviews@lists.linux.dev To: "Mengmeng Zhao" Cc: linux-ext4@vger.kernel.org, tytso@mit.edu In-Reply-To: <20261113070621.273953-9-mengmeng.zhao@linux.dev> References: <20261113070621.273953-1-mengmeng.zhao@linux.dev> <20261113070621.273953-9-mengmeng.zhao@linux.dev> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Fri, 13 Nov 2026 07:26:58 +0000 X-Mailing-List: linux-ext4@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list > From: Mengmeng Zhao >=20 > Advertise FMODE_CAN_DMABUF_IO for inodes that can support dma-buf I/O > and implement ->init_dma_buf_io_ctx() by registering the buffer against > the filesystem's block device. The capability follows > ext4_dio_alignment(), so an inode that can never do direct I/O - > fs-verity, data=3Djournal or inline data - is refused at open, and > encrypted inodes are refused on the inode flag, which is set even > without CONFIG_FS_ENCRYPTION. The inode is rechecked at registration > because DAX can be enabled after the file was opened. >=20 > A dma-buf iterator has no pages to copy from, so it must never reach the > page cache. ext4_buffered_read_iter() and ext4_buffered_write_iter() are > the single sinks of the buffered fallbacks and refuse it there; a short > direct I/O write still reports its progress, and the DAX write path > refuses at its entry instead of after starting a journal handle. >=20 > Signed-off-by: Mengmeng Zhao > Signed-off-by: Li Wang Sashiko has reviewed this patch and found no issues. --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20261113070621.2739= 53-1-mengmeng.zhao@linux.dev?part=3D8