NACK/Cmnt: [SRU][jammy][PATCH 0/6] Backport RDMA DMABUF

[Stefan Bader]

On 25.10.23 22:07, Ian May wrote:
> SRU Justification:
> 
> [Impact]
> 
> * From Nvidia:
> 
> "We are working on a high performance networking solution with real customers. That solution is being developed using the Ubuntu 22.04 LTS distro release and the distro kernel (lowlatency flavour). This “dma_buf” patchset consists of upstreamed patches that allow buffers to be shared between drivers thus enhancing performance while reducing copying of data.
> 
> Our team is currently engaged in the development of a high-performance networking solution tailored to meet the demands of real-world customers. This cutting-edge solution is being crafted on the foundation of Ubuntu 22.04 LTS, utilizing the distribution's kernel, specifically the lowlatency flavor.
> 
> At the heart of our innovation lies the transformative "dma_buf" patchset, comprising a series of patches that have been integrated into the upstream kernel in 5.16 and 5.17. These patches introduce a groundbreaking capability: enabling the seamless sharing of buffers among various drivers. This not only bolsters the solution's performance but also minimizes the need for data copying, effectively enhancing efficiency across the board.
> 
> The new functionality is isolated such that existing user will not execute these new code paths."
> 
> Upstream Reference
> 
> https://lore.kernel.org/all/20211012120903.96933-1-galpress@amazon.com/
> https://lore.kernel.org/all/0-v1-bd147097458e+ede-umem_dmabuf_jgg@nvidia.com/
> The patch "[PATCH 1/4] net/mlx5: Add IFC bits for mkey ATS" is already in Jammy and was included in:
> "2a1e6097e9b9 UBUNTU: SAUCE: RDMA/core: Updated ib_peer_memory"
> 
> [Test Plan]
> 
> * Testing instructions are outlined in the SF case and has been tested on in house hardware and externally by Nvidia.
> 
> [Where problems could occur?]
> 
> * This introduces new code paths so regression potential should be low.
> 
> [Other Info]
> 
> * SF#00370664
> 
> 
> Gal Pressman (3):
>    dma-buf: Fix pin callback comment
>    RDMA/umem: Allow pinned dmabuf umem usage
>    RDMA/efa: Add support for dmabuf memory regions
> 
> Jason Gunthorpe (3):
>    RDMA/core: Add UVERBS_ATTR_RAW_FD
>    RDMA/mlx5: Add support for dmabuf to devx umem
>    RDMA/mlx5: Enable ATS support for MRs and umems
> 
>   drivers/infiniband/core/umem_dmabuf.c    |  51 +++++++++
>   drivers/infiniband/core/uverbs_ioctl.c   |   8 ++
>   drivers/infiniband/hw/efa/efa.h          |   4 +
>   drivers/infiniband/hw/efa/efa_main.c     |   1 +
>   drivers/infiniband/hw/efa/efa_verbs.c    | 127 +++++++++++++++++------
>   drivers/infiniband/hw/mlx5/devx.c        |  54 +++++++---
>   drivers/infiniband/hw/mlx5/mlx5_ib.h     |  36 +++++++
>   drivers/infiniband/hw/mlx5/mr.c          |   5 +-
>   include/linux/dma-buf.h                  |   4 +-
>   include/rdma/ib_umem.h                   |  11 ++
>   include/rdma/uverbs_ioctl.h              |  13 +++
>   include/uapi/rdma/mlx5_user_ioctl_cmds.h |   1 +
>   12 files changed, 265 insertions(+), 50 deletions(-)
> 

Rejected for the following reasons:
This is to formally close the thread. This was retracted before but the 
thread somehow fell into cracks of being too busy.


-Stefan
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