[PATCH] cxl/acpi: Add Null check for adev

[Chenyuan Yang <chenyuan0y@gmail.com>]

Not all devices have an ACPI companion fwnode, so adev might be NULL.
This is similar to the commit cd2fd6eab480
("platform/x86: int3472: Check for adev == NULL").

Add a check for adev not being set and return -ENODEV in that case to
avoid a possible NULL pointer deref in cxl_acpi_probe().

Signed-off-by: Chenyuan Yang <chenyuan0y@gmail.com>
---
 drivers/cxl/acpi.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/cxl/acpi.c b/drivers/cxl/acpi.c
index cb14829bb9be..9195001db3c1 100644
--- a/drivers/cxl/acpi.c
+++ b/drivers/cxl/acpi.c
@@ -823,6 +823,9 @@ static int cxl_acpi_probe(struct platform_device *pdev)
 	struct acpi_device *adev = ACPI_COMPANION(host);
 	struct cxl_cfmws_context ctx;
 
+	if (!adev)
+		return -ENODEV;
+
 	device_lock_set_class(&pdev->dev, &cxl_root_key);
 	rc = devm_add_action_or_reset(&pdev->dev, cxl_acpi_lock_reset_class,
 				      &pdev->dev);
-- 
2.34.1