[v3,03/14] cxl/mem: Cache port created by the mem dev

Commit Message

Ben Widawsky Jan. 28, 2022, 12:26 a.m. UTC

Since region programming sees all components in the topology as a port,
it's required that endpoints are treated equally. The easiest way to go
from endpoint to port is to simply cache it at creation time.

Signed-off-by: Ben Widawsky <[e-mail]>

---
Changes since v2:
- Rebased on Dan's latest port/mem changes
- Keep a reference to the port until the memdev goes away
- add action to release device reference for the port
---
 drivers/cxl/cxlmem.h |  2 ++
 drivers/cxl/mem.c    | 35 ++++++++++++++++++++++++++++-------
 2 files changed, 30 insertions(+), 7 deletions(-)

Comments

Dan Williams Feb. 17, 2022, 1:20 a.m. UTC | #1

On Thu, Jan 27, 2022 at 4:27 PM Ben Widawsky <[e-mail]> wrote:
>
> Since region programming sees all components in the topology as a port,
> it's required that endpoints are treated equally. The easiest way to go
> from endpoint to port is to simply cache it at creation time.

As of 8dd2bc0f8e02 ("cxl/mem: Add the cxl_mem driver"),
cxl_endpoint_autoremove() already sets cxlmd drvdata to @endpoint, so
this patch isn't needed.

Patch

diff --git a/drivers/cxl/cxlmem.h b/drivers/cxl/cxlmem.h
index 7ba0edb4a1ab..2b8c66616d4e 100644
--- a/drivers/cxl/cxlmem.h
+++ b/drivers/cxl/cxlmem.h
@@ -37,6 +37,7 @@ 
  * @id: id number of this memdev instance.
  * @detach_work: active memdev lost a port in its ancestry
  * @component_reg_phys: register base of component registers
+ * @port: The port created by this device
  */
 struct cxl_memdev {
 	struct device dev;
@@ -44,6 +45,7 @@  struct cxl_memdev {
 	struct cxl_dev_state *cxlds;
 	struct work_struct detach_work;
 	int id;
+	struct cxl_port *port;
 };
 
 static inline struct cxl_memdev *to_cxl_memdev(struct device *dev)
diff --git a/drivers/cxl/mem.c b/drivers/cxl/mem.c
index 27f9dd0d55b6..c36219193886 100644
--- a/drivers/cxl/mem.c
+++ b/drivers/cxl/mem.c
@@ -45,26 +45,31 @@  static int wait_for_media(struct cxl_memdev *cxlmd)
 	return 0;
 }
 
-static int create_endpoint(struct cxl_memdev *cxlmd,
-			   struct cxl_port *parent_port)
+static struct cxl_port *create_endpoint(struct cxl_memdev *cxlmd,
+					struct cxl_port *parent_port)
 {
 	struct cxl_dev_state *cxlds = cxlmd->cxlds;
 	struct cxl_port *endpoint;
+	int rc;
 
 	endpoint = devm_cxl_add_port(&parent_port->dev, &cxlmd->dev,
 				     cxlds->component_reg_phys, parent_port);
 	if (IS_ERR(endpoint))
-		return PTR_ERR(endpoint);
+		return endpoint;
 
 	dev_dbg(&cxlmd->dev, "add: %s\n", dev_name(&endpoint->dev));
 
 	if (!endpoint->dev.driver) {
 		dev_err(&cxlmd->dev, "%s failed probe\n",
 			dev_name(&endpoint->dev));
-		return -ENXIO;
+		return ERR_PTR(-ENXIO);
 	}
 
-	return cxl_endpoint_autoremove(cxlmd, endpoint);
+	rc = cxl_endpoint_autoremove(cxlmd, endpoint);
+	if (rc)
+		return ERR_PTR(rc);
+
+	return endpoint;
 }
 
 /**
@@ -127,11 +132,18 @@  __mock bool cxl_dvsec_decode_init(struct cxl_dev_state *cxlds)
 	return do_hdm_init;
 }
 
+static void delete_memdev(void *dev)
+{
+	struct cxl_memdev *cxlmd = dev;
+
+	put_device(&cxlmd->port->dev);
+}
+
 static int cxl_mem_probe(struct device *dev)
 {
 	struct cxl_memdev *cxlmd = to_cxl_memdev(dev);
 	struct cxl_dev_state *cxlds = cxlmd->cxlds;
-	struct cxl_port *parent_port;
+	struct cxl_port *parent_port, *ep_port;
 	int rc;
 
 	/*
@@ -201,7 +213,16 @@  static int cxl_mem_probe(struct device *dev)
 		goto out;
 	}
 
-	rc = create_endpoint(cxlmd, parent_port);
+	ep_port = create_endpoint(cxlmd, parent_port);
+	if (IS_ERR(ep_port)) {
+		rc = PTR_ERR(ep_port);
+		goto out;
+	}
+
+	get_device(&ep_port->dev);
+	cxlmd->port = ep_port;
+
+	rc = devm_add_action_or_reset(dev, delete_memdev, cxlmd);
 out:
 	cxl_device_unlock(&parent_port->dev);
 	put_device(&parent_port->dev);