Hi Leon,

On 17.03.2026 20:05, Leon Romanovsky wrote:

On Mon, Mar 16, 2026 at 09:06:44PM +0200, Leon Romanovsky wrote:

quoted

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.

<...>

quoted

---
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