[PATCH v5 2/3] driver-core: record error on bus registration

[Florian Schmaus <flo@geekplace.eu>]

If bus_register() fails on a driver then record the error code so that
it can be inspected later on.

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

Notes:
    - Also record ENOMEM error code.

 drivers/base/bus.c     | 6 +++++-
 include/linux/device.h | 1 +
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/base/bus.c b/drivers/base/bus.c
index ef6183306b40..5814ecb07648 100644
--- a/drivers/base/bus.c
+++ b/drivers/base/bus.c
@@ -152,6 +152,7 @@ static void bus_release(struct kobject *kobj)
 
 	kfree(priv);
 	bus->p = NULL;
+	bus->bus_register_error = 0;
 }
 
 static struct kobj_type bus_ktype = {
@@ -848,8 +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;
@@ -915,6 +918,7 @@ int bus_register(struct bus_type *bus)
 out:
 	kfree(bus->p);
 	bus->p = NULL;
+	bus->bus_register_error = retval;
 	return retval;
 }
 EXPORT_SYMBOL_GPL(bus_register);
diff --git a/include/linux/device.h b/include/linux/device.h
index 0059b99e1f25..5b1f3c08bebe 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -135,6 +135,7 @@ struct bus_type {
 	const struct iommu_ops *iommu_ops;
 
 	struct subsys_private *p;
+	int bus_register_error;
 	struct lock_class_key lock_key;
 
 	bool force_dma;
-- 
2.16.1