Re: [PATCH v3 0/8] RDMA: Enable operation with DMA debug enabled

[Marek Szyprowski]

Hi Leon,

On 17.03.2026 20:05, Leon Romanovsky wrote:
> On Mon, Mar 16, 2026 at 09:06:44PM +0200, Leon Romanovsky wrote:
>> Add a new DMA_ATTR_REQUIRE_COHERENT attribute to the DMA API to mark
>> mappings that must run on a DMA‑coherent system. Such buffers cannot
>> use the SWIOTLB path, may overlap with CPU caches, and do not depend on
>> explicit cache flushing.
>>
>> Mappings using this attribute are rejected on systems where cache
>> side‑effects could lead to data corruption, and therefore do not need
>> the cache‑overlap debugging logic. This series also includes fixes for
>> DMA_ATTR_CPU_CACHE_CLEAN handling.
>> Thanks.
> <...>
>
>> ---
>> Leon Romanovsky (8):
>>        dma-debug: Allow multiple invocations of overlapping entries
>>        dma-mapping: handle DMA_ATTR_CPU_CACHE_CLEAN in trace output
>>        dma-mapping: Clarify valid conditions for CPU cache line overlap
>>        dma-mapping: Introduce DMA require coherency attribute
>>        dma-direct: prevent SWIOTLB path when DMA_ATTR_REQUIRE_COHERENT is set
>>        iommu/dma: add support for DMA_ATTR_REQUIRE_COHERENT attribute
>>        RDMA/umem: Tell DMA mapping that UMEM requires coherency
>>        mm/hmm: Indicate that HMM requires DMA coherency
>>
>>   Documentation/core-api/dma-attributes.rst | 38 ++++++++++++++++++++++++-------
>>   drivers/infiniband/core/umem.c            |  5 ++--
>>   drivers/iommu/dma-iommu.c                 | 21 +++++++++++++----
>>   drivers/virtio/virtio_ring.c              | 10 ++++----
>>   include/linux/dma-mapping.h               | 15 ++++++++----
>>   include/trace/events/dma.h                |  4 +++-
>>   kernel/dma/debug.c                        |  9 ++++----
>>   kernel/dma/direct.h                       |  7 +++---
>>   kernel/dma/mapping.c                      |  6 +++++
>>   mm/hmm.c                                  |  4 ++--
>>   10 files changed, 86 insertions(+), 33 deletions(-)
> Marek,
>
> Despite the "RDMA ..." tag in the subject, the diffstat clearly shows that
> you are the appropriate person to take this patch.

I plan to take the first 2 patches to the dma-mapping-fixes branch 
(v7.0-rc) and the next to dma-mapping-for-next. Should I also take the 
RDMA and HMM patches, or do You want a stable branch for merging them 
via respective subsystem trees?

Best regards
-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland