From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 8135F3859D7 for ; Fri, 18 Sep 2026 09:26:49 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789723610; cv=none; b=mJaBqNHNLdmmomh7lRPml0XAWEEl3UiSSaYUcntziF/dojgsJMY3LNsrkXpZlw3YdP/T7femZt49NYymV89yDmNMtzipXvPCvcR4ErIyg9d3tOTde4NaxFHGTzSvENw4oQwQfs1PX9C4JJw66X0zDOHsfah4nxT/9gGNzKgT9IE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789723610; c=relaxed/simple; bh=NcT0edn5Hh6sGcazFXdJmlIVzx0UQ4v7e3TC9wJS+qw=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=jrAPD0kMnVUEIXO9h+w6o52oNaAuWj8j6ll8SRRm3UGUG3KIiZcNAHe3nYAAWE2FHGBiRm383fmMUHYTzrrdXjxbR8A/1xvtImbAk+wlEDx8HvED9m3ZK3zBA30jO/d3sQeyf58TniQ8JHTqThInBrosXid2Rlx85KnyDFrir1U= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=GM0bEtNg; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="GM0bEtNg" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 612E01F000FF; Fri, 18 Sep 2026 09:26:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789723609; bh=dfg26xIbqNSEIuifg+ZnaXT1R/Q/4Ny4ZcICa+zT48A=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=GM0bEtNgRqqp8uqp0uyn2hfNkO3JS0noyol9FSmtrQM/ETvjJ0UA0O5+u/511EOgY 3PtyWexS5gxQ51FAH534wKD8scFcaOp3AlLhrwjtqcLtIDj9Ggw1m1qoK7CZWKjT7H BgNwJ2nZD89O8kZGIUE0xOg/EEeVDYTcabqv5jGxGC9LwRikVUUt8AX4GG3gnjNV2G hz9dVgXRBSfzvwphdFjlPskb/WSlZ11RCfjNXFmiDVlQJwMNGirlSFcEwc6YbifZm6 zEi/d2fmLDNOb42/rTkipG3+Y5O+VqZh43eoJtbCPIqhUjLHnFTICZMVTr5Udr5RB4 CHKwVOQq1CNig== Message-ID: <7bb73c96-fc2a-4cbe-ba17-b68646393922@kernel.org> Date: Fri, 18 Sep 2026 16:26:45 +0700 Precedence: bulk X-Mailing-List: linux-scsi@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v4 02/10] scsi: scsi_debug: Make atomic writes and ZBC emulation mutually exclusive To: Niklas Cassel , "James E.J. Bottomley" , "Martin K. Petersen" Cc: linux-scsi@vger.kernel.org, John Garry References: <20260918062910.1709791-12-cassel@kernel.org> <20260918062910.1709791-14-cassel@kernel.org> From: Damien Le Moal Content-Language: en-US Organization: Western Digital Research In-Reply-To: <20260918062910.1709791-14-cassel@kernel.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 2026/09/18 13:29, Niklas Cassel wrote: > There are no SMR drives that support atomic writes. Emulating a device > that supports both is emulating something that a user cannot encounter, > rather than the drives that exist, and it means maintaining the zone > handling of a command that no zoned device implements. > > Nothing in the standards forbids the combination. For what would be by > far the most common case, a host managed SMR drive whose logical block > size equals its physical block size, there is no problem in the two > features being combined: the drive vendor only has to give atomic > writes an alignment that makes sense with regards to ZBC, for instance > equal to the physical block size. This is therefore a choice not to > complicate scsi_debug, rather than a restriction that the standards > impose. > > Refuse the combination at initialisation. If SMR drives that support > atomic writes ever become a thing, this can be changed back. > > Suggested-by: Damien Le Moal > Assisted-by: LLM > Signed-off-by: Niklas Cassel Looks good. Reviewed-by: Damien Le Moal -- Damien Le Moal Western Digital Research