From: Jason Gunthorpe <jgg@ziepe.ca>
To: Leon Romanovsky <leon@kernel.org>
Cc: "Marek Szyprowski" <m.szyprowski@samsung.com>,
"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>,
"Steven Rostedt" <rostedt@goodmis.org>,
"Masami Hiramatsu" <mhiramat@kernel.org>,
"Mathieu Desnoyers" <mathieu.desnoyers@efficios.com>,
"Joerg Roedel" <joro@8bytes.org>, "Will Deacon" <will@kernel.org>,
"Andrew Morton" <akpm@linux-foundation.org>,
iommu@lists.linux.dev, linux-kernel@vger.kernel.org,
linux-doc@vger.kernel.org, virtualization@lists.linux.dev,
linux-rdma@vger.kernel.org, linux-trace-kernel@vger.kernel.org,
linux-mm@kvack.org
Subject: Re: [PATCH v2 7/8] RDMA/umem: Tell DMA mapping that UMEM requires coherency
Date: Thu, 12 Mar 2026 09:22:18 -0300 [thread overview]
Message-ID: <20260312122218.GF1469476@ziepe.ca> (raw)
In-Reply-To: <20260311-dma-debug-overlap-v2-7-e00bc2ca346d@nvidia.com>
On Wed, Mar 11, 2026 at 09:08:50PM +0200, Leon Romanovsky wrote:
> From: Leon Romanovsky <leonro@nvidia.com>
>
> The RDMA subsystem exposes DMA regions through the verbs interface, which
> assumes a coherent system. Use the DMA_ATTR_REQUIRE_COHERENCE attribute to
> ensure coherency and avoid taking the SWIOTLB path.
>
> In addition, a given region may be exported multiple times, which will trigger
> warnings about cacheline overlaps. These warnings are suppressed when using
> the new attribute.
> Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
> ---
> drivers/infiniband/core/umem.c | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Jason
next prev parent reply other threads:[~2026-03-12 12:22 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-03-11 19:08 [PATCH v2 0/8] RDMA: Enable operation with DMA debug enabled Leon Romanovsky
2026-03-11 19:08 ` [PATCH v2 1/8] dma-debug: Allow multiple invocations of overlapping entries Leon Romanovsky
2026-03-11 19:08 ` [PATCH v2 2/8] dma-mapping: handle DMA_ATTR_CPU_CACHE_CLEAN in trace output Leon Romanovsky
2026-03-11 19:08 ` [PATCH v2 3/8] dma-mapping: Clarify valid conditions for CPU cache line overlap Leon Romanovsky
2026-03-11 19:08 ` [PATCH v2 4/8] dma-mapping: Introduce DMA require coherency attribute Leon Romanovsky
2026-03-12 12:19 ` Jason Gunthorpe
2026-03-12 16:46 ` Leon Romanovsky
2026-03-11 19:08 ` [PATCH v2 5/8] dma-direct: prevent SWIOTLB path when DMA_ATTR_REQUIRE_COHERENT is set Leon Romanovsky
2026-03-12 12:20 ` Jason Gunthorpe
2026-03-12 16:47 ` Leon Romanovsky
2026-03-11 19:08 ` [PATCH v2 6/8] iommu/dma: add support for DMA_ATTR_REQUIRE_COHERENT attribute Leon Romanovsky
2026-03-11 19:08 ` [PATCH v2 7/8] RDMA/umem: Tell DMA mapping that UMEM requires coherency Leon Romanovsky
2026-03-12 12:22 ` Jason Gunthorpe [this message]
2026-03-12 12:34 ` Jason Gunthorpe
2026-03-11 19:08 ` [PATCH v2 8/8] mm/hmm: Indicate that HMM requires DMA coherency Leon Romanovsky
2026-03-12 12:26 ` Jason Gunthorpe
2026-03-12 16:50 ` Leon Romanovsky
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