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Commit 7c7a9bcc authored by Roland Dreier's avatar Roland Dreier
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IB/cm: Fix infiniband_cm class kobject ref counting 



Commit 9af57b7a ("IB/cm: Add basic performance counters") introduced a
bug in how the reference count for cm_class.subsys.kobj was handled:
the path that released a device did a kobject_put() on that kobject, but
there was no kobject_get() in the path the handles adding a device.  So
the reference count ended up too low, which leads to bad things.  Fix up
and simplify the reference counting to avoid this.

(Actually, I introduced the bug when fixing the patch up to match some
of Greg's kobject changes, but who's counting)

Signed-off-by: default avatarRoland Dreier <rolandd@cisco.com>
parent ab64b960

drivers/infiniband/core/cm.c

+8 −14
Original line number Diff line number Diff line
@@ -3612,18 +3612,12 @@ struct class cm_class = { 
};

EXPORT_SYMBOL(cm_class);



static void cm_remove_fs_obj(struct kobject *obj)

{

	kobject_put(obj->parent);

	kobject_put(obj);

}



static int cm_create_port_fs(struct cm_port *port)

{

	int i, ret;



	ret = kobject_init_and_add(&port->port_obj, &cm_port_obj_type,

				   kobject_get(&port->cm_dev->dev_obj),

				   &port->cm_dev->dev_obj,

				   "%d", port->port_num);

	if (ret) {

		kfree(port);
@@ -3633,7 +3627,7 @@ static int cm_create_port_fs(struct cm_port *port) 
	for (i = 0; i < CM_COUNTER_GROUPS; i++) {

		ret = kobject_init_and_add(&port->counter_group[i].obj,

					   &cm_counter_obj_type,

					   kobject_get(&port->port_obj),

					   &port->port_obj,

					   "%s", counter_group_names[i]);

		if (ret)

			goto error;
@@ -3643,8 +3637,8 @@ static int cm_create_port_fs(struct cm_port *port) 


error:

	while (i--)

		cm_remove_fs_obj(&port->counter_group[i].obj);

	cm_remove_fs_obj(&port->port_obj);

		kobject_put(&port->counter_group[i].obj);

	kobject_put(&port->port_obj);

	return ret;



}
@@ -3654,9 +3648,9 @@ static void cm_remove_port_fs(struct cm_port *port) 
	int i;



	for (i = 0; i < CM_COUNTER_GROUPS; i++)

		cm_remove_fs_obj(&port->counter_group[i].obj);

		kobject_put(&port->counter_group[i].obj);



	cm_remove_fs_obj(&port->port_obj);

	kobject_put(&port->port_obj);

}



static void cm_add_one(struct ib_device *device)
@@ -3740,7 +3734,7 @@ static void cm_add_one(struct ib_device *device) 
		ib_unregister_mad_agent(port->mad_agent);

		cm_remove_port_fs(port);

	}

	cm_remove_fs_obj(&cm_dev->dev_obj);

	kobject_put(&cm_dev->dev_obj);

}



static void cm_remove_one(struct ib_device *device)
@@ -3767,7 +3761,7 @@ static void cm_remove_one(struct ib_device *device) 
		ib_unregister_mad_agent(port->mad_agent);

		cm_remove_port_fs(port);

	}

	cm_remove_fs_obj(&cm_dev->dev_obj);

	kobject_put(&cm_dev->dev_obj);

}



static int __init ib_cm_init(void)