From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tom Tucker Subject: MLX4 Cq Question Date: Fri, 17 May 2013 14:25:44 -0500 Message-ID: <51968438.7070907@opengridcomputing.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Sender: linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: roland-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org Cc: "linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" List-Id: linux-rdma@vger.kernel.org Hi Roland, I'm looking at the Linux MLX4 net driver and found something that confuses me mightily. In particular in the file net/ethernet/mellanox/mlx4/cq.c, the mlx4_ib_completion function does not take any kind of lock when looking up the SW CQ in the radix tree, however, the mlx4_cq_event function does. In addition if I go look at the code paths where cq are removed from this tree, they are protected by spin_lock_irq. So I am baffled at this point as to what the locking strategy is and how this is supposed to work. I'm sure I'm missing something and would greatly appreciate it if someone would explain this. Thanks, Tom -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html