Subject: Re: [PATCH v8 08/27] cxl: add functions for resource request/release by a driver

From: Jonathan Cameron <[email-masked]>
Date: Tue, 24 Dec 2024 17:25:35 +0000

On Mon, 16 Dec 2024 16:10:23 +0000
[email-masked] wrote:

> From: Alejandro Lucero <[email-masked]>
> 
> Create accessors for an accel driver requesting and releasing a resource.
> 
> Signed-off-by: Alejandro Lucero <[email-masked]>
> Reviewed-by: Ben Cheatham <[email-masked]>
> Reviewed-by: Zhi Wang <[email-masked]>
> Reviewed-by: Fan Ni <[email-masked]>
Hi Alejandro,

Minor comment inline. Either way
Reviewed-by: Jonathan Cameron <[email-masked]>

> ---
>  drivers/cxl/core/memdev.c | 45 +++++++++++++++++++++++++++++++++++++++
>  include/cxl/cxl.h         |  2 ++
>  2 files changed, 47 insertions(+)
> 
> diff --git a/drivers/cxl/core/memdev.c b/drivers/cxl/core/memdev.c
> index 99f533caae1e..c414b0fbbead 100644
> --- a/drivers/cxl/core/memdev.c
> +++ b/drivers/cxl/core/memdev.c
> @@ -744,6 +744,51 @@ 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)
> +{
> +	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;
> +		}
> +
> +		return request_resource(&cxlds->dpa_res, &cxlds->ram_res);
> +	case CXL_RES_PMEM:
> +		if (!resource_size(&cxlds->pmem_res)) {
> +			dev_err(cxlds->dev,
> +				"resource request for pmem with size 0\n");
> +			return -EINVAL;
> +		}
> +		return request_resource(&cxlds->dpa_res, &cxlds->pmem_res);
> +	default:
> +		dev_err(cxlds->dev, "unsupported resource type (%u)\n", type);
> +		return -EINVAL;
> +	}
> +}
> +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);
		return release_resource() unless a later
patch add something that happens after this...

> +		break;
> +	case CXL_RES_PMEM:
> +		rc = release_resource(&cxlds->pmem_res);
same

> +		break;
> +	default:
> +		dev_err(cxlds->dev, "unknown resource type (%u)\n", type);
> +		return -EINVAL;
> +	}
> +
> +	return rc;
With above, this isn't needed.
> +}
> +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