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

[Florian Schmaus]

Signed-off-by: Florian Schmaus <f...@geekplace.eu>
---

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