From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 A815529A1 for ; Thu, 6 Nov 2025 04:35:18 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762403718; cv=none; b=uIDKly+NV9ArO8c08FKwsvCBQxVPPdHMO7JUan81hxtlMpogPX2gA+nlchl9CofQjbX4R3OzolHU6CKYbs/K8STFCkhmV5BZKKfGufaGT7gNmC9f572UTdV8/gKKqdnCKNXOteimcyIajiLuWH7dq/HPZvD8Xqs6iVC/ED9uaxQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762403718; c=relaxed/simple; bh=0NKkoXcj12kuxL014ecN1w6NAn33C9rghjSJpEtZHOQ=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=eZz3iffGQrB7KBdHgS/aLtqQHPBhcSe0LB4jfqf+wU9ETEmgrLzjkSLqxZE3+NfoeilsXCoy43MYuq0X0WscYv7sdTdmthpMIobgNMepv+NuaWNwlc927AZxK42vfAq4Yeu6BGF+LBdvTk7T4odBke1W6PU1b9UuDfqH3h4YUvw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=SRhxtk6g; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="SRhxtk6g" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 40DB4C4CEFB; Thu, 6 Nov 2025 04:35:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1762403718; bh=0NKkoXcj12kuxL014ecN1w6NAn33C9rghjSJpEtZHOQ=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=SRhxtk6gfU1muu+tMgG1D8XEc0ewEnfV04V0exyom2RoBQhZcQOjEMqkNWSvu0Vs8 peSoVNT6VYaf1COyMVHSoExN2wH66ClRS2sx4HzihyGsCagH/Cqthxev+3u+Jm/Svq wZD27M2UyZmmM+fxTAMxFSC/+NT39285Adiorm6ACfmMWtkLXbn91oKIlc/lyWchUT xKXEgr+1XNZCklVA6iRbxd5KhO/9wD1QSTIccf+9oHDNLXkSJsxgXsbvaMOBPkmtmw IYZF1cHciX2VqkKw+fgsteejQEEUy4ANlWBJoboaiZ1KcjmU86BhDmRF199gzihRKq tTYHiIXLSmlTQ== Message-ID: <57db9d0f-299b-4043-82ec-55d502642631@kernel.org> Date: Thu, 6 Nov 2025 13:31:24 +0900 Precedence: bulk X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCHv2 4/4] null_blk: allow byte aligned memory offsets To: Keith Busch , linux-block@vger.kernel.org, hch@lst.de, axboe@kernel.dk, hans.holmberg@wdc.com Cc: Keith Busch References: <20251106015447.1372926-1-kbusch@meta.com> <20251106015447.1372926-5-kbusch@meta.com> From: Damien Le Moal Content-Language: en-US Organization: Western Digital Research In-Reply-To: <20251106015447.1372926-5-kbusch@meta.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 11/6/25 10:54 AM, Keith Busch wrote: > From: Keith Busch > > Allowing byte aligned memory provides a nice testing ground for .dma_alignment = 1 means a minimum of 2-bytes alignment, no ? > direct-io. > > Signed-off-by: Keith Busch Looks good. Reviewed-by: Damien Le Moal Note: on top of this, for testing, I think it would be nice to add a config parameter to allow changing dma_alignment to higher values, and check requests when processing them against that alignment. That could allow testing corner cases or emulate devices with weird DMA alignment constraints. -- Damien Le Moal Western Digital Research