[PATCH v4 3/3] driver-core: print bus registration error value

[Florian Schmaus]

Signed-off-by: Florian Schmaus <flo@xxxxxxxxxxxx>
---

Notes:
    - Use correct member name 'bus_register_error'
    - Only print out error code if it is non-zero

 drivers/base/bus.c    |  4 +++-
 drivers/base/driver.c | 13 ++++++++++---
 2 files changed, 13 insertions(+), 4 deletions(-)

diff --git a/drivers/base/bus.c b/drivers/base/bus.c
index dce677dddba4..5814ecb07648 100644
--- a/drivers/base/bus.c
+++ b/drivers/base/bus.c
@@ -849,8 +849,10 @@ int bus_register(struct bus_type *bus)
 	struct lock_class_key *key = &bus->lock_key;
 
 	priv = kzalloc(sizeof(struct subsys_private), GFP_KERNEL);
-	if (!priv)
+	if (!priv) {
+		bus->bus_register_error = -ENOMEM;
 		return -ENOMEM;
+	}
 
 	priv->bus = bus;
 	bus->p = priv;
diff --git a/drivers/base/driver.c b/drivers/base/driver.c
index 203fa731e3ee..a798aeae08c7 100644
--- a/drivers/base/driver.c
+++ b/drivers/base/driver.c
@@ -149,9 +149,16 @@ int driver_register(struct device_driver *drv)
 	struct device_driver *other;
 
 	if (!drv->bus->p) {
-		pr_err("Driver '%s' was unable to register with bus_type '%s'"
-			   " because it was not initialized.\n",
-			   drv->name, drv->bus->name);
+		if (drv->bus->bus_register_error) {
+			pr_err("Driver '%s' was unable to register with bus_type '%s'",
+				   " (error: %d).\n",
+				   drv->name, drv->bus->name,
+				   drv->bus->bus_register_error);
+		} else {
+			pr_err("Driver '%s' was unable to register with bus_type '%s'",
+				   " because it was not initialized.\n",
+				   drv->name, drv->bus->name);
+		}
 		return -EINVAL;
 	}
 
-- 
2.16.1