From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932671AbcHNLAf (ORCPT ); Sun, 14 Aug 2016 07:00:35 -0400 Received: from mail-pa0-f47.google.com ([209.85.220.47]:33046 "EHLO mail-pa0-f47.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933183AbcHNLAc (ORCPT ); Sun, 14 Aug 2016 07:00:32 -0400 Date: Sat, 13 Aug 2016 11:35:59 -0700 From: Stephen Hemminger To: Vitaly Kuznetsov Cc: netdev@vger.kernel.org, devel@linuxdriverproject.org, linux-kernel@vger.kernel.org, Haiyang Zhang , "K. Y. Srinivasan" Subject: [RFC 1/2] netvsc: reference counting fix Message-ID: <20160813113559.617b7c55@xeon-e3> In-Reply-To: <1470913137-29167-3-git-send-email-vkuznets@redhat.com> References: <1470913137-29167-1-git-send-email-vkuznets@redhat.com> <1470913137-29167-3-git-send-email-vkuznets@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This is how I think it should be fixed, but not tested yet. Subjec: netvsc: use device not module reference counts Fix how the cross-device reference counting is handled. When VF is associated with the synthetic interface, the VF driver module should still be able to be unloaded. The module unload code will callback with NETDEV_UNREGISTER event which breaks the connection safely. (Fixes 9f4b5ba5db4 hv_netvsc: Implement support for VF drivers on Hyper-V) Signed-off-by: Stephen Hemminger --- a/drivers/net/hyperv/netvsc_drv.c 2016-08-13 11:25:40.243995863 -0700 +++ b/drivers/net/hyperv/netvsc_drv.c 2016-08-13 11:25:40.239995844 -0700 @@ -1220,10 +1220,8 @@ static int netvsc_register_vf(struct net return NOTIFY_DONE; netdev_info(ndev, "VF registering: %s\n", vf_netdev->name); - /* - * Take a reference on the module. - */ - try_module_get(THIS_MODULE); + + dev_hold(vf_netdev); netvsc_dev->vf_netdev = vf_netdev; return NOTIFY_OK; } @@ -1345,7 +1343,7 @@ static int netvsc_unregister_vf(struct n netdev_info(ndev, "VF unregistering: %s\n", vf_netdev->name); netvsc_dev->vf_netdev = NULL; - module_put(THIS_MODULE); + dev_put(vf_netdev); return NOTIFY_OK; }