Re: [PATCH rdma-next 00/10] RDMA: Extend uverbs umem support for QP buffers and doorbell records

[Leon Romanovsky <leon@kernel.org>]

On Tue, Feb 03, 2026 at 09:49:52AM +0100, Jiri Pirko wrote:
> From: Jiri Pirko <jiri@nvidia.com>
> 
> This patchset extends the existing CQ umem buffer infrastructure to QP
> creation and adds doorbell record (DBR) umem support for both CQ and QP.
> 
> The kernel already supports CQ creation with externally provided umem
> buffers. This patchset:
> 
> 1. Adds umem reference counting to simplify memory lifecycle management.
> 2. Adds mlx5 driver implementation for the existing CQ buffer umem support.
> 3. Extends QP creation to support external SQ/RQ buffer umems.
> 4. Adds doorbell record umem support for both CQ and QP.
> 5. Implements all extensions in mlx5 driver.
> 
> This enables integration with dmabuf exporters for specialized memory
> types, such as GPU memory for GPU-direct RDMA scenarios.

What do you mean by that?

Are you referring to the RDMA dma‑buf exporter from Yishai?  
The GPU dma‑buf exporters already work correctly with the existing  
RDMA importer.

Thanks