[PATCH 10/17] cxl/cache, mem: Prevent RAS register mapping race

[Ben Cheatham <Benjamin.Cheatham@amd.com>]

CXL type 2 devices will register both a struct cxl_memdev and struct
cxl_cachedev, both of which will attempt to map the parent dport's RAS
registers in cxl_dport_init_ras_reporting(). While the immediate call
fails gracefully, an error is emitted in the dmesg log by
cxl_map_component_regs().

Avoid this error message by checking if the RAS registers are already
mapped while the port's device lock is held.

Signed-off-by: Ben Cheatham <Benjamin.Cheatham@amd.com>
---
 drivers/cxl/cache.c | 11 +++++++++++
 drivers/cxl/mem.c   |  5 +++--
 2 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/drivers/cxl/cache.c b/drivers/cxl/cache.c
index 630452d53acc..4c9280c0ea72 100644
--- a/drivers/cxl/cache.c
+++ b/drivers/cxl/cache.c
@@ -58,6 +58,7 @@ static int cxl_cache_probe(struct device *dev)
 {
 	struct cxl_cachedev *cxlcd = to_cxl_cachedev(dev);
 	struct cxl_dev_state *cxlds = cxlcd->cxlds;
+	struct device *endpoint_parent;
 	struct cxl_dport *dport;
 	int rc;
 
@@ -72,6 +73,16 @@ static int cxl_cache_probe(struct device *dev)
 		return -ENXIO;
 	}
 
+	if (dport->rch)
+		endpoint_parent = parent_port->uport_dev;
+	else
+		endpoint_parent = &parent_port->dev;
+
+	scoped_guard(device, endpoint_parent) {
+		if (!cxlds->cxlmd)
+			cxl_dport_init_ras_reporting(dport, dev);
+	}
+
 	return 0;
 }
 
diff --git a/drivers/cxl/mem.c b/drivers/cxl/mem.c
index 3b230f8c5925..35706ec1b7e1 100644
--- a/drivers/cxl/mem.c
+++ b/drivers/cxl/mem.c
@@ -129,9 +129,10 @@ static int cxl_mem_probe(struct device *dev)
 	else
 		endpoint_parent = &parent_port->dev;
 
-	cxl_dport_init_ras_reporting(dport, dev);
-
 	scoped_guard(device, endpoint_parent) {
+		if (!cxlds->cxlcd)
+			cxl_dport_init_ras_reporting(dport, dev);
+
 		if (!endpoint_parent->driver) {
 			dev_err(dev, "CXL port topology %s not enabled\n",
 				dev_name(endpoint_parent));
-- 
2.51.1