From: Lars Ellenberg Date: Mon, 28 Apr 2014 16:43:35 +0000 (+0200) Subject: drbd: use list_first_entry_or_null in first_peer_device/first_connection X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=ec4a340789be16831ae96be5f7552238a7a6e903;p=linux-beck.git 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 Signed-off-by: Lars Ellenberg Signed-off-by: Jens Axboe --- diff --git a/drivers/block/drbd/drbd_int.h b/drivers/block/drbd/drbd_int.h index 297ba406cc2b..a76ceb344d64 100644 --- a/drivers/block/drbd/drbd_int.h +++ b/drivers/block/drbd/drbd_int.h @@ -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); }