Re: [PATCH v12 18/23] cxl: allow region creation by type2 drivers

[Jonathan Cameron <Jonathan.Cameron@huawei.com>]

On Mon, 31 Mar 2025 15:45:50 +0100
<alejandro.lucero-palau@amd.com> wrote:

> From: Alejandro Lucero <alucerop@amd.com>
> 
> Creating a CXL region requires userspace intervention through the cxl
> sysfs files. Type2 support should allow accelerator drivers to create
> such cxl region from kernel code.
> 
> Adding that functionality and integrating it with current support for
> memory expanders.
> 
> Based on https://lore.kernel.org/linux-cxl/168592159835.1948938.1647215579839222774.stgit@dwillia2-xfh.jf.intel.com/
> 
> Signed-off-by: Alejandro Lucero <alucerop@amd.com>
> ---
>  drivers/cxl/core/region.c | 135 +++++++++++++++++++++++++++++++++++---
>  drivers/cxl/port.c        |   5 +-
>  include/cxl/cxl.h         |   4 ++
>  3 files changed, 135 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c
> index 892fb799bf46..f2e1d5719a70 100644
> --- a/drivers/cxl/core/region.c
> +++ b/drivers/cxl/core/region.c
> @@ -2310,6 +2310,17 @@ static int cxl_region_detach(struct cxl_endpoint_decoder *cxled)
>  	return rc;
>  }
>  
> +int cxl_accel_region_detach(struct cxl_endpoint_decoder *cxled)
> +{
> +	int rc;
> +
> +	guard(rwsem_write)(&cxl_region_rwsem);
> +	cxled->part = -1;
> +	rc = cxl_region_detach(cxled);
> +	return rc;
`	return cxl_region_detach()

Check for any other cases of this.  If we don't clean them up now we'll
just get patches form those who run scripts to find these and that's
just noise upstream that I'd rather avoid.

> +}
> +EXPORT_SYMBOL_NS_GPL(cxl_accel_region_detach, "CXL");