[PATCH 04/21] driver core: bus: convert bus_create/remove_file to be constant

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

bus_create_file() and bus_remove_file() can be made to take a constant
bus pointer, as it should not be modifying anything in the bus
structure.  Make this change and move the functions to use the internal
subsys_get/put() logic as well, to prevent the use of the back-pointer
in struct bus_type.

Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/base/bus.c         | 28 +++++++++++++++++-----------
 include/linux/device/bus.h |  5 ++---
 2 files changed, 19 insertions(+), 14 deletions(-)

diff --git a/drivers/base/bus.c b/drivers/base/bus.c
index 7949302663f9..8debbe00b4ca 100644
--- a/drivers/base/bus.c
+++ b/drivers/base/bus.c
@@ -175,24 +175,30 @@ static const struct sysfs_ops bus_sysfs_ops = {
 	.store	= bus_attr_store,
 };
 
-int bus_create_file(struct bus_type *bus, struct bus_attribute *attr)
+int bus_create_file(const struct bus_type *bus, struct bus_attribute *attr)
 {
+	struct subsys_private *sp = bus_to_subsys(bus);
 	int error;
-	if (bus_get(bus)) {
-		error = sysfs_create_file(&bus->p->subsys.kobj, &attr->attr);
-		bus_put(bus);
-	} else
-		error = -EINVAL;
+
+	if (!sp)
+		return -EINVAL;
+
+	error = sysfs_create_file(&sp->subsys.kobj, &attr->attr);
+
+	subsys_put(sp);
 	return error;
 }
 EXPORT_SYMBOL_GPL(bus_create_file);
 
-void bus_remove_file(struct bus_type *bus, struct bus_attribute *attr)
+void bus_remove_file(const struct bus_type *bus, struct bus_attribute *attr)
 {
-	if (bus_get(bus)) {
-		sysfs_remove_file(&bus->p->subsys.kobj, &attr->attr);
-		bus_put(bus);
-	}
+	struct subsys_private *sp = bus_to_subsys(bus);
+
+	if (!sp)
+		return;
+
+	sysfs_remove_file(&sp->subsys.kobj, &attr->attr);
+	subsys_put(sp);
 }
 EXPORT_SYMBOL_GPL(bus_remove_file);
 
diff --git a/include/linux/device/bus.h b/include/linux/device/bus.h
index f0c8bf91b07a..f6537f5fc535 100644
--- a/include/linux/device/bus.h
+++ b/include/linux/device/bus.h
@@ -135,9 +135,8 @@ struct bus_attribute {
 #define BUS_ATTR_WO(_name) \
 	struct bus_attribute bus_attr_##_name = __ATTR_WO(_name)
 
-extern int __must_check bus_create_file(struct bus_type *,
-					struct bus_attribute *);
-extern void bus_remove_file(struct bus_type *, struct bus_attribute *);
+int __must_check bus_create_file(const struct bus_type *bus, struct bus_attribute *attr);
+void bus_remove_file(const struct bus_type *bus, struct bus_attribute *attr);
 
 /* Generic device matching functions that all busses can use to match with */
 int device_match_name(struct device *dev, const void *name);
-- 
2.39.1