Re: [PATCH RFC 06/18] accel/qda: Add memory manager for CB devices

[Dmitry Baryshkov]

On Tue, Feb 24, 2026 at 12:39:00AM +0530, Ekansh Gupta wrote:
> Introduce a per-device memory manager for the QDA driver that tracks
> IOMMU-capable compute context-bank (CB) devices. Each CB device is
> represented by a qda_iommu_device and registered with a central
> qda_memory_manager instance owned by qda_dev.
> 
> The memory manager maintains an xarray of devices and assigns a
> unique ID to each CB. It also provides basic lifetime management

Sounds like IDR.

> and a workqueue for deferred device removal. qda_cb_setup_device()

What is deferred device removal? Why do you need it?

> now allocates a qda_iommu_device for each CB and registers it with
> the memory manager after DMA configuration succeeds.
> 
> qda_init_device() is extended to allocate and initialize the memory
> manager, while qda_deinit_device() will tear it down in later
> patches. This prepares the QDA driver for fine-grained memory and
> IOMMU domain management tied to individual CB devices.
> 
> Signed-off-by: Ekansh Gupta <ekansh.gupta@xxxxxxxxxxxxxxxx>
> ---
>  drivers/accel/qda/Makefile             |   1 +
>  drivers/accel/qda/qda_cb.c             |  32 +++++++
>  drivers/accel/qda/qda_drv.c            |  46 ++++++++++
>  drivers/accel/qda/qda_drv.h            |   3 +
>  drivers/accel/qda/qda_memory_manager.c | 152 +++++++++++++++++++++++++++++++++
>  drivers/accel/qda/qda_memory_manager.h | 101 ++++++++++++++++++++++
>  6 files changed, 335 insertions(+)
> 

-- 
With best wishes
Dmitry