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 B4CEB20330 for ; Mon, 16 Jun 2025 06:43:26 +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=1750056206; cv=none; b=RuXXKJiOCYABU+XhyZSlK5oIcB/bLe37s6mo25GBzvq8Yd2uJVK6HVR40N9/dXqMge8sxZhbP9APrzHdtf6+KfeMeYJIeAMdRnq1LgLksEBMLibCJ29/SkO0XZm6cLv067GlRqiCUCe+F2B6zLDQh2mEJPufy6WZdTZnr8C1QFU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750056206; c=relaxed/simple; bh=i8eZ5db7jwLf3O2OU4sJwtCvyGnyULzOXR46Z6sekOg=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=DBEbvo2/HI7mZzlD0TH/wQdwxFlLbP2cKq9+ucbggi8mzGoe8vNH8BzU9o2HQhBzBgCPUemmEQULFIjmGlSYcqGpda8np2h06yD3Uw4+sSt8aZ1RgfxTmZbuJlbCPQEUpqlealfg40ZpZKMzQKzOKI5qLRvtFqN5809kbZwdXb8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Ea2GD93o; 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="Ea2GD93o" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3DCCDC4CEEA; Mon, 16 Jun 2025 06:43:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1750056206; bh=i8eZ5db7jwLf3O2OU4sJwtCvyGnyULzOXR46Z6sekOg=; h=Date:Reply-To:Subject:To:Cc:References:From:In-Reply-To:From; b=Ea2GD93oQhfMVYrQqOBlhv16244neKYQsZ5tMJvqX4kKmN7Cu7dUxD6fMUJhdufGQ D6iPWyjHsx48zcXJTnZtaOuAupGhsUInQzo5yhmnnqm1VvfdYVdNCTlG4CRmnC594E cqI9WHBK0swPEqvw05iJgLssF6bWQUi3GLFIR31MO+9vGN6c2gR8zP7Jfsu3b4/v7V /IMHMQlqFoRNYu9BprdLtUt5hKiobkNmnPPokSQm0OcNOaWzE7XUQh2KXtb7FXIkw4 ROJrXWpn78imzqt/xuKQU0bgd/DbXvwHEWBCs7p96qNzE59E20ZLC/a1mrnde4DxT+ Rkj2ZwzBNG2uA== Message-ID: <2105172c-5540-40d0-9573-15001b745648@kernel.org> Date: Mon, 16 Jun 2025 08:43:22 +0200 Precedence: bulk X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Reply-To: Daniel Gomez Subject: Re: [PATCH 2/9] block: add scatterlist-less DMA mapping helpers To: Christoph Hellwig Cc: Jens Axboe , Keith Busch , Sagi Grimberg , Chaitanya Kulkarni , Kanchan Joshi , Leon Romanovsky , Nitesh Shetty , Logan Gunthorpe , linux-block@vger.kernel.org, linux-nvme@lists.infradead.org References: <20250610050713.2046316-1-hch@lst.de> <20250610050713.2046316-3-hch@lst.de> <20250616050247.GA860@lst.de> Content-Language: en-US From: Daniel Gomez Organization: kernel.org In-Reply-To: <20250616050247.GA860@lst.de> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 16/06/2025 07.02, Christoph Hellwig wrote: > On Wed, Jun 11, 2025 at 03:43:07PM +0200, Daniel Gomez wrote: >>> +struct blk_dma_iter { >>> + /* Output address range for this iteration */ >>> + dma_addr_t addr; >>> + u32 len; >>> + >>> + /* Status code. Only valid when blk_rq_dma_map_iter_* returned false */ >>> + blk_status_t status; >> >> This comment does not match with blk_rq_dma_map_iter_start(). It returns false >> and status is BLK_STS_INVAL. > > I went over you comment a few times and still don't understand it. The way I read the comment is that status is only valid when blk_rq_dma_map_iter_* returns false. But blk_rq_dma_map_iter_start() can return false and an invalid status (in the default switch case). Assuming the comment is the right thing, I'd expect a valid status for that case: --- a/block/blk-mq-dma.c +++ b/block/blk-mq-dma.c @@ -179,7 +179,6 @@ bool blk_rq_dma_map_iter_start(struct request *req, struct device *dma_dev, req->cmd_flags &= ~REQ_P2PDMA; break; default: - iter->status = BLK_STS_INVAL; return false; } }