From: Jason Gunthorpe <jgg@ziepe.ca>
To: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: "Leon Romanovsky" <leon@kernel.org>,
"Robin Murphy" <robin.murphy@arm.com>,
"Michael S. Tsirkin" <mst@redhat.com>,
"Petr Tesarik" <ptesarik@suse.com>,
"Jonathan Corbet" <corbet@lwn.net>,
"Shuah Khan" <skhan@linuxfoundation.org>,
"Jason Wang" <jasowang@redhat.com>,
"Xuan Zhuo" <xuanzhuo@linux.alibaba.com>,
"Eugenio Pérez" <eperezma@redhat.com>,
iommu@lists.linux.dev, linux-kernel@vger.kernel.org,
linux-doc@vger.kernel.org, virtualization@lists.linux.dev,
linux-rdma@vger.kernel.org
Subject: Re: [PATCH 2/3] dma-mapping: Clarify valid conditions for CPU cache line overlap
Date: Mon, 9 Mar 2026 10:20:38 -0300 [thread overview]
Message-ID: <20260309132038.GL1687929@ziepe.ca> (raw)
In-Reply-To: <c1d058f3-f864-4ed7-9f7a-683d6f4bf1ce@samsung.com>
On Mon, Mar 09, 2026 at 01:30:24PM +0100, Marek Szyprowski wrote:
> My question here is if RDMA works on any non-coherent DMA systems?
The in kernel components do work, like storage, nvme over fabrics, netdev.
The user API (uverbs) does not work at all, and has never worked.
I think DRM has similar issues too where most of their DMA API usage
is OK but some places where they interact win pin_user_pages() have
the same issues as RDMA.
This is why I'd like a new attribute DMA_ATTR_REQUIRE_COHERENCE that
these special cases can use to fail instead of data corrupt.
Jason
next prev parent reply other threads:[~2026-03-09 13:20 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-03-07 16:49 [PATCH 0/3] RDMA: Enable runs with DMA debug enabled Leon Romanovsky
2026-03-07 16:49 ` [PATCH 1/3] dma-debug: Allow multiple invocations of overlapping entries Leon Romanovsky
2026-03-07 16:49 ` [PATCH 2/3] dma-mapping: Clarify valid conditions for CPU cache line overlap Leon Romanovsky
2026-03-08 18:19 ` Jason Gunthorpe
2026-03-08 18:49 ` Leon Romanovsky
2026-03-08 23:09 ` Jason Gunthorpe
2026-03-09 9:03 ` Leon Romanovsky
2026-03-09 12:30 ` Marek Szyprowski
2026-03-09 13:20 ` Jason Gunthorpe [this message]
2026-03-09 15:05 ` Leon Romanovsky
2026-03-09 15:13 ` Jason Gunthorpe
2026-03-10 9:45 ` Marek Szyprowski
2026-03-10 12:34 ` Jason Gunthorpe
2026-03-10 18:27 ` Leon Romanovsky
2026-03-10 21:08 ` Marek Szyprowski
2026-03-10 23:34 ` Jason Gunthorpe
2026-03-07 16:49 ` [PATCH 3/3] RDMA/umem: Tell DMA debug that cacheline overlap is expected Leon Romanovsky
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