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

From: Fan Ni <fan.ni@samsung.com>
To: Dan Williams <dan.j.williams@intel.com>
Cc: "linux-cxl@vger.kernel.org" <linux-cxl@vger.kernel.org>,
	"ira.weiny@intel.com" <ira.weiny@intel.com>,
	"navneet.singh@intel.com" <navneet.singh@intel.com>
Subject: Re: [PATCH 09/19] cxl/memdev: Formalize endpoint port linkage
Date: Wed, 7 Jun 2023 16:47:55 +0000	[thread overview]
Message-ID: <20230607164748.GA2354150@bgt-140510-bm03> (raw)
In-Reply-To: <168592154692.1948938.3074738916245299862.stgit@dwillia2-xfh.jf.intel.com>

On Sun, Jun 04, 2023 at 04:32:27PM -0700, 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: Fan Ni <fan.ni@samsung.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;
>  };
> 
>