From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751154AbdKTKlV (ORCPT ); Mon, 20 Nov 2017 05:41:21 -0500 Received: from mx1.redhat.com ([209.132.183.28]:42390 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750952AbdKTKlU (ORCPT ); Mon, 20 Nov 2017 05:41:20 -0500 From: Eduardo Otubo To: xen-devel@lists.xenproject.org Cc: netdev@vger.kernel.org, paul.durrant@citrix.com, wei.liu2@citrix.com, linux-kernel@vger.kernel.org, vkuznets@redhat.com, cavery@redhat.com, cheshi@redhat.com, mgamal@redhat.com, Eduardo Otubo Subject: [PATCH] xen-netfront: remove warning when unloading module Date: Mon, 20 Nov 2017 11:41:09 +0100 Message-Id: <20171120104109.11585-1-otubo@redhat.com> X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.28]); Mon, 20 Nov 2017 10:41:20 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When unloading module xen_netfront from guest, dmesg would output warning messages like below: [ 105.236836] xen:grant_table: WARNING: g.e. 0x903 still in use! [ 105.236839] deferring g.e. 0x903 (pfn 0x35805) This problem relies on netfront and netback being out of sync. By the time netfront revokes the g.e.'s netback didn't have enough time to free all of them, hence displaying the warnings on dmesg. The trick here is to make netfront to wait until netback frees all the g.e.'s and only then continue to cleanup for the module removal, and this is done by manipulating both device states. Signed-off-by: Eduardo Otubo --- drivers/net/xen-netfront.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/drivers/net/xen-netfront.c b/drivers/net/xen-netfront.c index 8b8689c6d887..b948e2a1ce40 100644 --- a/drivers/net/xen-netfront.c +++ b/drivers/net/xen-netfront.c @@ -2130,6 +2130,17 @@ static int xennet_remove(struct xenbus_device *dev) dev_dbg(&dev->dev, "%s\n", dev->nodename); + xenbus_switch_state(dev, XenbusStateClosing); + while (xenbus_read_driver_state(dev->otherend) != XenbusStateClosing){ + cpu_relax(); + schedule(); + } + xenbus_switch_state(dev, XenbusStateClosed); + while (dev->xenbus_state != XenbusStateClosed){ + cpu_relax(); + schedule(); + } + xennet_disconnect_backend(info); unregister_netdev(info->netdev); -- 2.13.6