On Wed, Mar 18, 2026 at 09:03:00AM +0100, Marek Szyprowski wrote: > 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?
I suggest taking all patches into the -fixes branch, as the "RDMA/..." patch also resolves the dmesg splat. With -fixes, there is no need to worry about a shared branch since we do not expect merge conflicts in that area. If you still prefer to split the series between -fixes and -next, it would be better to use a shared branch in that case. There are patches on the RDMA list targeted for -next that touch ib_umem_get(). Thanks > > Best regards > -- > Marek Szyprowski, PhD > Samsung R&D Institute Poland > >
