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From: Christoph Hellwig <hch@lst.de>
To: Keith Busch <kbusch@kernel.org>
Cc: Christoph Hellwig <hch@lst.de>, Keith Busch <kbusch@meta.com>,
	linux-block@vger.kernel.org, linux-nvme@lists.infradead.org,
	axboe@kernel.dk, leonro@nvidia.com
Subject: Re: [PATCHv2 7/7] nvme: convert metadata mapping to dma iter
Date: Tue, 22 Jul 2025 07:49:40 +0200	[thread overview]
Message-ID: <20250722054940.GA13634@lst.de> (raw)
In-Reply-To: <aH49fa1qH4HN5P7w@kbusch-mbp>

On Mon, Jul 21, 2025 at 07:15:41AM -0600, Keith Busch wrote:
> > This should probably just set up the linear metadata pointer instead
> > of a single-segment SGL.
> 
> Okay, but we should still use SGL with user passthrough commands for
> memory safety. Even if we have an iommu protecting access, there's still
> a possibility of corrupting adjacent iova's if using MPTR.

True.

> In this patch, the nr_meta_descriptors value matches the sg_list length.
> The only real reason I need this 'nr_' value is to distinguish the
> single data descriptor condition from the segment descriptor use, but I
> can just add an iod flag for that too and save some space.

Yes, that would be great.


      reply	other threads:[~2025-07-22  5:54 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-07-20 18:40 [PATCHv2 0/7] blk dma iter for metadata Keith Busch
2025-07-20 18:40 ` [PATCHv2 1/7] blk-mq-dma: move the bio and bvec_iter to blk_dma_iter Keith Busch
2025-07-21  7:37   ` Christoph Hellwig
2025-07-21  7:42   ` Christoph Hellwig
2025-07-22  2:33     ` Keith Busch
2025-07-22  5:53       ` Christoph Hellwig
2025-07-20 18:40 ` [PATCHv2 2/7] blk-mq-dma: set the bvec being iterated Keith Busch
2025-07-21  7:38   ` Christoph Hellwig
2025-07-20 18:40 ` [PATCHv2 3/7] blk-mq-dma: require unmap caller provide p2p map type Keith Busch
2025-07-21  7:39   ` Christoph Hellwig
2025-07-20 18:40 ` [PATCHv2 4/7] blk-mq: remove REQ_P2PDMA flag Keith Busch
2025-07-21  7:39   ` Christoph Hellwig
2025-07-20 18:40 ` [PATCHv2 5/7] blk-mq-dma: move common dma start code to a helper Keith Busch
2025-07-21  7:40   ` Christoph Hellwig
2025-07-20 18:40 ` [PATCHv2 6/7] blk-mq-dma: add support for mapping integrity metadata Keith Busch
2025-07-20 22:51   ` kernel test robot
2025-07-21  3:18   ` kernel test robot
2025-07-21  7:46   ` Christoph Hellwig
2025-07-20 18:40 ` [PATCHv2 7/7] nvme: convert metadata mapping to dma iter Keith Busch
2025-07-21  7:50   ` Christoph Hellwig
2025-07-21 13:15     ` Keith Busch
2025-07-22  5:49       ` Christoph Hellwig [this message]

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