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 2B94425C70D for ; Thu, 6 Nov 2025 04:40:53 +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=1762404054; cv=none; b=ZBRgT/aTiUvjhvXxW9ohyeihrfV/TESR75V1QMN8hvT4ccm08RWuZyAMAyg8imO+ckz12q1GgMZtBPXRSifQWzifH3Nu3aomi1WbN08t5Gy45mSxaxnu78+uUtuDRE+PNJj504zfsOINdGKTE6GuKCwhY+66oMpktxFnht9puWQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762404054; c=relaxed/simple; bh=Z2r7PThb4hJGpMVbTJZ/QgwyTAvBU/r2M3NW6kyUu/o=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=UkxyV9toMTvpuc1i920LGF7FyhiFdgd360MrR0PeSauihUbtLQ3DXwylym2KrtOMnAu2Lg2SfqyeiSuFjRx4nkXYibIJzfiWzMR7U+WDm0m5PHmv/4eHI5Gi4wHPo4iQGkNCbXZkpG4IXSXftKsPJNsZz1WcTxx8OuW2rKOqJxY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=TVDOIT3Q; 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="TVDOIT3Q" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7E36CC4CEF7; Thu, 6 Nov 2025 04:40:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1762404053; bh=Z2r7PThb4hJGpMVbTJZ/QgwyTAvBU/r2M3NW6kyUu/o=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=TVDOIT3Q99QCsurV4cHsZGtbSorfHvdw3k6CPLG3eVnVxy9SFd4gYXJZo9QjCdZmV NLylgL+kavruRjkigDNXsCFRyHAT7sHjTWEpfGdjucL3v2inSK9PEJqx9Y2wdyzg4J jBDUmiWR3Z5qli4/ih4vqItCSwN1ZS5KpYuziqcx2sRL8hOjq9yzvfpnLFP1AzLCyT d4nSBmB/nkUpik1cTAXsYoBBPTs7q3y7s1hVy/jxsa6l+hrHFn7wij2Spl8auKtnZJ 0ggeuhVLL6RzdxoTl5qdqm7OgYTi+bfuRlH8Vyyr0GvmyMIECgskvtUtEbf/wmKEPc CpunI120KKjGg== Date: Wed, 5 Nov 2025 21:40:51 -0700 From: Keith Busch To: Damien Le Moal Cc: Keith Busch , linux-block@vger.kernel.org, hch@lst.de, axboe@kernel.dk, hans.holmberg@wdc.com Subject: Re: [PATCHv2 4/4] null_blk: allow byte aligned memory offsets Message-ID: References: <20251106015447.1372926-1-kbusch@meta.com> <20251106015447.1372926-5-kbusch@meta.com> <57db9d0f-299b-4043-82ec-55d502642631@kernel.org> Precedence: bulk X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <57db9d0f-299b-4043-82ec-55d502642631@kernel.org> On Thu, Nov 06, 2025 at 01:31:24PM +0900, Damien Le Moal wrote: > > 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. Yeah, that sounds like it fits in with this limit: there are other similar limits paramaterized by null_blk, like the virtual boundary, so user defined dma alignment makes sense.