Re: [PATCH v6 08/28] cxl: add functions for resource request/release by a driver

[Zhi Wang <zhiw@nvidia.com>]

On Mon, 2 Dec 2024 17:12:02 +0000
<alejandro.lucero-palau@amd.com> wrote:

LGTM. Reviewed-by: Zhi Wang <zhiw@nvidia.com>

> From: Alejandro Lucero <alucerop@amd.com>
> 
> Create accessors for an accel driver requesting and releasing a resource.
> 
> Signed-off-by: Alejandro Lucero <alucerop@amd.com>
> Reviewed-by: Ben Cheatham <benjamin.cheatham@amd.com>
> ---
>  drivers/cxl/core/memdev.c | 51 +++++++++++++++++++++++++++++++++++++++
>  include/cxl/cxl.h         |  2 ++
>  2 files changed, 53 insertions(+)
> 
> diff --git a/drivers/cxl/core/memdev.c b/drivers/cxl/core/memdev.c
> index 8257993562b6..1d43fa60525b 100644
> --- a/drivers/cxl/core/memdev.c
> +++ b/drivers/cxl/core/memdev.c
> @@ -744,6 +744,57 @@ int cxl_set_resource(struct cxl_dev_state *cxlds, struct resource res,
>  }
>  EXPORT_SYMBOL_NS_GPL(cxl_set_resource, CXL);
>  
> +int cxl_request_resource(struct cxl_dev_state *cxlds, enum cxl_resource type)
> +{
> +	int rc;
> +
> +	switch (type) {
> +	case CXL_RES_RAM:
> +		if (!resource_size(&cxlds->ram_res)) {
> +			dev_err(cxlds->dev,
> +				"resource request for ram with size 0\n");
> +			return -EINVAL;
> +		}
> +
> +		rc = request_resource(&cxlds->dpa_res, &cxlds->ram_res);
> +		break;
> +	case CXL_RES_PMEM:
> +		if (!resource_size(&cxlds->pmem_res)) {
> +			dev_err(cxlds->dev,
> +				"resource request for pmem with size 0\n");
> +			return -EINVAL;
> +		}
> +		rc = request_resource(&cxlds->dpa_res, &cxlds->pmem_res);
> +		break;
> +	default:
> +		dev_err(cxlds->dev, "unsupported resource type (%u)\n", type);
> +		return -EINVAL;
> +	}
> +
> +	return rc;
> +}
> +EXPORT_SYMBOL_NS_GPL(cxl_request_resource, CXL);
> +
> +int cxl_release_resource(struct cxl_dev_state *cxlds, enum cxl_resource type)
> +{
> +	int rc;
> +
> +	switch (type) {
> +	case CXL_RES_RAM:
> +		rc = release_resource(&cxlds->ram_res);
> +		break;
> +	case CXL_RES_PMEM:
> +		rc = release_resource(&cxlds->pmem_res);
> +		break;
> +	default:
> +		dev_err(cxlds->dev, "unknown resource type (%u)\n", type);
> +		return -EINVAL;
> +	}
> +
> +	return rc;
> +}
> +EXPORT_SYMBOL_NS_GPL(cxl_release_resource, CXL);
> +
>  static int cxl_memdev_release_file(struct inode *inode, struct file *file)
>  {
>  	struct cxl_memdev *cxlmd =
> diff --git a/include/cxl/cxl.h b/include/cxl/cxl.h
> index 18fb01adcf19..44664c9928a4 100644
> --- a/include/cxl/cxl.h
> +++ b/include/cxl/cxl.h
> @@ -42,4 +42,6 @@ bool cxl_pci_check_caps(struct cxl_dev_state *cxlds,
>  			unsigned long *expected_caps,
>  			unsigned long *current_caps);
>  int cxl_pci_accel_setup_regs(struct pci_dev *pdev, struct cxl_dev_state *cxlds);
> +int cxl_request_resource(struct cxl_dev_state *cxlds, enum cxl_resource type);
> +int cxl_release_resource(struct cxl_dev_state *cxlds, enum cxl_resource type);
>  #endif