Re: [PATCH v3 06/20] cxl: add functions for resource request/release by a driver

Jonathan Cameron
2024-09-13T17:35:24Z

On Sat, 7 Sep 2024 09:18:22 +0100
alejandro.lucero-palau@amd.com wrote:

> From: Alejandro Lucero <alucerop@amd.com>
>
> Create accessors for an accel driver requesting and
> releaseing a resource.
>
> Signed-off-by: Alejandro Lucero <alucerop@amd.com>
> ---
> drivers/cxl/core/memdev.c | 40 ++++++++++++++++++++++++++++++
> drivers/net/ethernet/sfc/efx_cxl.c | 7 ++++++
> include/linux/cxl/cxl.h | 2 ++
> 3 files changed, 49 insertions(+)
>
> diff --git a/drivers/cxl/core/memdev.c b/drivers/cxl/core/memdev.c
> index 10c0a6990f9a..a7d8daf4a59b 100644
> --- a/drivers/cxl/core/memdev.c
> +++ b/drivers/cxl/core/memdev.c
> @@ -744,6 +744,46 @@ 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_ACCEL_RES_RAM:
> + rc = request_resource(&cxlds->dpa_res, &cxlds->ram_res);
> + break;
> + case CXL_ACCEL_RES_PMEM:
> + rc = request_resource(&cxlds->dpa_res, &cxlds->pmem_res);
> + break;

return request_resource()

> + default:
> + dev_err(cxlds->dev, "unknown resource type (%u)\n", type);

No unknown. We know exactly what it is (DPA) but we don't have it.
Unexpected maybe?

> + 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_ACCEL_RES_RAM:
> + rc = release_resource(&cxlds->ram_res);
> + break;
> + case CXL_ACCEL_RES_PMEM:
> + rc = release_resource(&cxlds->pmem_res);
return ..

> + break;
> + default:
> + dev_err(cxlds->dev, "unknown resource type (%u)\n", type);

As above. Probably know what we got, it it unexpected not unknown.

> + 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/drivers/net/ethernet/sfc/efx_cxl.c b/drivers/net/ethernet/sfc/efx_cxl.c
> index fee143e94c1f..80259c8317fd 100644
> --- a/drivers/net/ethernet/sfc/efx_cxl.c
> +++ b/drivers/net/ethernet/sfc/efx_cxl.c
> @@ -72,6 +72,12 @@ int efx_cxl_init(struct efx_nic *efx)
> goto err;
> }
>
> + rc = cxl_request_resource(cxl->cxlds, CXL_ACCEL_RES_RAM);
> + if (rc) {
> + pci_err(pci_dev, "CXL request resource failed");
> + goto err;
> + }
> +
> return 0;
> err:
> kfree(cxl->cxlds);
> @@ -84,6 +90,7 @@ int efx_cxl_init(struct efx_nic *efx)
> void efx_cxl_exit(struct efx_nic *efx)
> {
> if (efx->cxl) {
> + cxl_release_resource(efx->cxl->cxlds, CXL_ACCEL_RES_RAM);
> kfree(efx->cxl->cxlds);
> kfree(efx->cxl);
> }
> diff --git a/include/linux/cxl/cxl.h b/include/linux/cxl/cxl.h
> index f2dcba6cdc22..22912b2d9bb2 100644
> --- a/include/linux/cxl/cxl.h
> +++ b/include/linux/cxl/cxl.h
> @@ -52,4 +52,6 @@ int cxl_set_resource(struct cxl_dev_state *cxlds, struct resource res,
> bool cxl_pci_check_caps(struct cxl_dev_state *cxlds, u32 expected_caps,
> u32 *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