drbd: use list_first_entry_or_null in first_peer_device/first_connection

If there are no peer_devices or connections, I'd rather have NULL
than some "arbitrary" address pretending to point to a struct.

Helps to avoid hard to debug symptoms, in case we ever try to use
and dereference a drbd_connection or drbd_peer_device
where we in fact don't have any connection at all.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
This commit is contained in:
Lars Ellenberg 2014-04-28 18:43:35 +02:00 committed by Jens Axboe
parent babea49ebe
commit ec4a340789

View File

@ -853,7 +853,7 @@ static inline struct drbd_device *minor_to_device(unsigned int minor)
static inline struct drbd_peer_device *first_peer_device(struct drbd_device *device)
{
return list_first_entry(&device->peer_devices, struct drbd_peer_device, peer_devices);
return list_first_entry_or_null(&device->peer_devices, struct drbd_peer_device, peer_devices);
}
#define for_each_resource(resource, _resources) \
@ -2222,7 +2222,7 @@ static inline void drbd_md_flush(struct drbd_device *device)
static inline struct drbd_connection *first_connection(struct drbd_resource *resource)
{
return list_first_entry(&resource->connections,
return list_first_entry_or_null(&resource->connections,
struct drbd_connection, connections);
}