Re: [PATCH 09/19] cxl/memdev: Formalize endpoint port linkage

[Dave Jiang <dave.jiang@intel.com>]

On 6/4/23 16:32, Dan Williams wrote:
> Move the endpoint port that the cxl_mem driver establishes from drvdata
> to a first class attribute. This is in preparation for device-memory
> drivers reusing the CXL core for memory region management. Those drivers
> need a type-safe method to retrieve their CXL port linkage. Leave
> drvdata for private usage of the cxl_mem driver not external consumers
> of a 'struct cxl_memdev' object.
>
> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
> ---
>   drivers/cxl/core/memdev.c |    4 ++--
>   drivers/cxl/core/pmem.c   |    2 +-
>   drivers/cxl/core/port.c   |    5 +++--
>   drivers/cxl/cxlmem.h      |    2 ++
>   4 files changed, 8 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/cxl/core/memdev.c b/drivers/cxl/core/memdev.c
> index 3f2d54f30548..65a685e5616f 100644
> --- a/drivers/cxl/core/memdev.c
> +++ b/drivers/cxl/core/memdev.c
> @@ -149,7 +149,7 @@ int cxl_trigger_poison_list(struct cxl_memdev *cxlmd)
>   	struct cxl_port *port;
>   	int rc;
>   
> -	port = dev_get_drvdata(&cxlmd->dev);
> +	port = cxlmd->endpoint;
>   	if (!port || !is_cxl_endpoint(port))
>   		return -EINVAL;
>   
> @@ -207,7 +207,7 @@ static struct cxl_region *cxl_dpa_to_region(struct cxl_memdev *cxlmd, u64 dpa)
>   	ctx = (struct cxl_dpa_to_region_context) {
>   		.dpa = dpa,
>   	};
> -	port = dev_get_drvdata(&cxlmd->dev);
> +	port = cxlmd->endpoint;
>   	if (port && is_cxl_endpoint(port) && port->commit_end != -1)
>   		device_for_each_child(&port->dev, &ctx, __cxl_dpa_to_region);
>   
> diff --git a/drivers/cxl/core/pmem.c b/drivers/cxl/core/pmem.c
> index f8c38d997252..fc94f5240327 100644
> --- a/drivers/cxl/core/pmem.c
> +++ b/drivers/cxl/core/pmem.c
> @@ -64,7 +64,7 @@ static int match_nvdimm_bridge(struct device *dev, void *data)
>   
>   struct cxl_nvdimm_bridge *cxl_find_nvdimm_bridge(struct cxl_memdev *cxlmd)
>   {
> -	struct cxl_port *port = find_cxl_root(dev_get_drvdata(&cxlmd->dev));
> +	struct cxl_port *port = find_cxl_root(cxlmd->endpoint);
>   	struct device *dev;
>   
>   	if (!port)
> diff --git a/drivers/cxl/core/port.c b/drivers/cxl/core/port.c
> index 71a7547a8d6f..6720ab22a494 100644
> --- a/drivers/cxl/core/port.c
> +++ b/drivers/cxl/core/port.c
> @@ -1167,7 +1167,7 @@ static struct device *grandparent(struct device *dev)
>   static void delete_endpoint(void *data)
>   {
>   	struct cxl_memdev *cxlmd = data;
> -	struct cxl_port *endpoint = dev_get_drvdata(&cxlmd->dev);
> +	struct cxl_port *endpoint = cxlmd->endpoint;
>   	struct cxl_port *parent_port;
>   	struct device *parent;
>   
> @@ -1182,6 +1182,7 @@ static void delete_endpoint(void *data)
>   		devm_release_action(parent, cxl_unlink_uport, endpoint);
>   		devm_release_action(parent, unregister_port, endpoint);
>   	}
> +	cxlmd->endpoint = NULL;
>   	device_unlock(parent);
>   	put_device(parent);
>   out:
> @@ -1193,7 +1194,7 @@ int cxl_endpoint_autoremove(struct cxl_memdev *cxlmd, struct cxl_port *endpoint)
>   	struct device *dev = &cxlmd->dev;
>   
>   	get_device(&endpoint->dev);
> -	dev_set_drvdata(dev, endpoint);
> +	cxlmd->endpoint = endpoint;
>   	cxlmd->depth = endpoint->depth;
>   	return devm_add_action_or_reset(dev, delete_endpoint, cxlmd);
>   }
> diff --git a/drivers/cxl/cxlmem.h b/drivers/cxl/cxlmem.h
> index b8bdf7490d2c..7ee78e79933c 100644
> --- a/drivers/cxl/cxlmem.h
> +++ b/drivers/cxl/cxlmem.h
> @@ -38,6 +38,7 @@
>    * @detach_work: active memdev lost a port in its ancestry
>    * @cxl_nvb: coordinate removal of @cxl_nvd if present
>    * @cxl_nvd: optional bridge to an nvdimm if the device supports pmem
> + * @endpoint: connection to the CXL port topology for this memory device
>    * @id: id number of this memdev instance.
>    * @depth: endpoint port depth
>    */
> @@ -48,6 +49,7 @@ struct cxl_memdev {
>   	struct work_struct detach_work;
>   	struct cxl_nvdimm_bridge *cxl_nvb;
>   	struct cxl_nvdimm *cxl_nvd;
> +	struct cxl_port *endpoint;
>   	int id;
>   	int depth;
>   };
>