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From: Leon Romanovsky <leonro@nvidia.com>
To: Christoph Hellwig <hch@lst.de>
Cc: Keith Busch <kbusch@kernel.org>,
	Ben Copeland <ben.copeland@linaro.org>,
	<linux-kernel@vger.kernel.org>, <lkft-triage@lists.linaro.org>,
	<regressions@lists.linux.dev>, <linux-nvme@lists.infradead.org>,
	"Dan Carpenter" <dan.carpenter@linaro.org>, <axboe@kernel.dk>,
	<sagi@grimberg.me>, <iommu@lists.linux.dev>
Subject: Re: next-20250627: IOMMU DMA warning during NVMe I/O completion after 06cae0e3f61c
Date: Tue, 1 Jul 2025 18:58:10 +0300	[thread overview]
Message-ID: <20250701155810.GE6278@unreal> (raw)
In-Reply-To: <20250701132936.GA18807@lst.de>

On Tue, Jul 01, 2025 at 03:29:36PM +0200, Christoph Hellwig wrote:
> On Mon, Jun 30, 2025 at 02:25:23PM -0600, Keith Busch wrote:
> > I think the PRP handling is broken. At the very least, handling the last
> > element is wrong if it appears at the end of the list, so I think we
> > need something like this:
> 
> Yeah.
> 
> > But even that, the PRP setup doesn't match the teardown. We're calling
> > dma_map_page() on each PRP even if consecutive PRP's came from the same
> > dma mapping segment. So even if it had been coalesced, but if the device
> > doesn't support SGLs, then it would use the prp unmap path.
> 
> Yes, that's broken, and I remember fixing it before.  A little digging
> shows that my fixes disappeared between the oct 30 version of Leon's
> dma-split branch and the latest one somewhere.

Oct, 30 belongs to RFC/first version of patches.

Thanks

  reply	other threads:[~2025-07-01 15:58 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <CGME20250630075218epcas5p1f3d467fffa468cac0ccd012c193e94df@epcas5p1.samsung.com>
2025-06-30  7:50 ` next-20250627: IOMMU DMA warning during NVMe I/O completion after 06cae0e3f61c Ben Copeland
2025-06-30 13:33   ` Christoph Hellwig
2025-06-30 19:51     ` Ben Copeland
2025-07-01 19:43       ` Keith Busch
2025-06-30 20:25     ` Keith Busch
2025-07-01  0:54       ` Keith Busch
2025-07-01 13:05       ` Ben Copeland
2025-07-01 14:20         ` Keith Busch
2025-07-01 13:29       ` Christoph Hellwig
2025-07-01 15:58         ` Leon Romanovsky [this message]
2025-07-01 21:00         ` Keith Busch
2025-07-03  9:30           ` Christoph Hellwig
2025-07-03 14:29             ` Keith Busch
2025-07-03 15:13               ` Ben Copeland
2025-07-03  5:54   ` Kanchan Joshi

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