[PATCH v2] apei/ghes: correctly return NULL for ghes_get_devices()

[Li Yang]

Since 315bada690e0 ("EDAC: Check for GHES preference in the
chipset-specific EDAC drivers"), vendor specific EDAC driver will not
probe correctly when CONFIG_ACPI_APEI_GHES is enabled but no GHES device
is present.  Make ghes_get_devices() return NULL when the GHES device
list is empty to fix the problem.

Fixes: 9057a3f7ac36 ("EDAC/ghes: Prepare to make ghes_edac a proper module")
Signed-off-by: Li Yang <leoyang.li@xxxxxxx>
Cc: Jia He <justin.he@xxxxxxx>
---

V2: fix the fallthrough case in x86 path

 drivers/acpi/apei/ghes.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c
index 34ad071a64e9..4382fe13ee3e 100644
--- a/drivers/acpi/apei/ghes.c
+++ b/drivers/acpi/apei/ghes.c
@@ -1544,6 +1544,8 @@ struct list_head *ghes_get_devices(void)
 
 			pr_warn_once("Force-loading ghes_edac on an unsupported platform. You're on your own!\n");
 		}
+	} else if (list_empty(&ghes_devs)) {
+		return NULL;
 	}
 
 	return &ghes_devs;
-- 
2.38.0