From patchwork Wed Mar 6 18:40:57 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Eduardo Habkost X-Patchwork-Id: 1052468 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (mailfrom) smtp.mailfrom=nongnu.org (client-ip=209.51.188.17; helo=lists.gnu.org; envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org; receiver=) Authentication-Results: ozlabs.org; dmarc=fail (p=none dis=none) header.from=redhat.com Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 44F2n72Jnvz9sB3 for ; Thu, 7 Mar 2019 05:47:22 +1100 (AEDT) Received: from localhost ([127.0.0.1]:37659 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1h1bZV-0004m7-JU for incoming@patchwork.ozlabs.org; Wed, 06 Mar 2019 13:47:17 -0500 Received: from eggs.gnu.org ([209.51.188.92]:38664) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1h1bYv-0004lr-Qr for qemu-devel@nongnu.org; Wed, 06 Mar 2019 13:46:42 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1h1bYu-00029T-RE for qemu-devel@nongnu.org; Wed, 06 Mar 2019 13:46:41 -0500 Received: from mx1.redhat.com ([209.132.183.28]:51621) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1h1bYu-00028N-3N for qemu-devel@nongnu.org; Wed, 06 Mar 2019 13:46:40 -0500 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 503A13092658; Wed, 6 Mar 2019 18:41:05 +0000 (UTC) Received: from localhost (ovpn-116-90.gru2.redhat.com [10.97.116.90]) by smtp.corp.redhat.com (Postfix) with ESMTP id CF94B5D707; Wed, 6 Mar 2019 18:41:04 +0000 (UTC) From: Eduardo Habkost To: Peter Maydell , qemu-devel@nongnu.org Date: Wed, 6 Mar 2019 15:40:57 -0300 Message-Id: <20190306184101.9974-2-ehabkost@redhat.com> In-Reply-To: <20190306184101.9974-1-ehabkost@redhat.com> References: <20190306184101.9974-1-ehabkost@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.43]); Wed, 06 Mar 2019 18:41:05 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PULL 1/5] qdev/core: fix qbus_is_full() X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Tony Krowiak Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-devel" From: Tony Krowiak The qbus_is_full(BusState *bus) function (qdev_monitor.c) compares the max_index value of the BusState structure with the max_dev value of the BusClass structure to determine whether the maximum number of children has been reached for the bus. The problem is, the max_index field of the BusState structure does not necessarily reflect the number of devices that have been plugged into the bus. Whenever a child device is plugged into the bus, the bus's max_index value is assigned to the child device and then incremented. If the child is subsequently unplugged, the value of the max_index does not change and no longer reflects the number of children. When the bus's max_index value reaches the maximum number of devices allowed for the bus (i.e., the max_dev field in the BusClass structure), attempts to plug another device will be rejected claiming that the bus is full -- even if the bus is actually empty. To resolve the problem, a new 'num_children' field is being added to the BusState structure to keep track of the number of children plugged into the bus. It will be incremented when a child is plugged, and decremented when a child is unplugged. Signed-off-by: Tony Krowiak Reviewed-by: Pierre Morel Reviewed-by: Halil Pasic Message-Id: <1545062250-7573-1-git-send-email-akrowiak@linux.ibm.com> Reviewed-by: Igor Mammedov Signed-off-by: Eduardo Habkost --- include/hw/qdev-core.h | 1 + hw/core/qdev.c | 3 +++ qdev-monitor.c | 2 +- 3 files changed, 5 insertions(+), 1 deletion(-) diff --git a/include/hw/qdev-core.h b/include/hw/qdev-core.h index e70a4bfa49..35b8154e8b 100644 --- a/include/hw/qdev-core.h +++ b/include/hw/qdev-core.h @@ -206,6 +206,7 @@ struct BusState { HotplugHandler *hotplug_handler; int max_index; bool realized; + int num_children; QTAILQ_HEAD(, BusChild) children; QLIST_ENTRY(BusState) sibling; }; diff --git a/hw/core/qdev.c b/hw/core/qdev.c index d59071b8ed..00a5a39c76 100644 --- a/hw/core/qdev.c +++ b/hw/core/qdev.c @@ -59,6 +59,8 @@ static void bus_remove_child(BusState *bus, DeviceState *child) snprintf(name, sizeof(name), "child[%d]", kid->index); QTAILQ_REMOVE(&bus->children, kid, sibling); + bus->num_children--; + /* This gives back ownership of kid->child back to us. */ object_property_del(OBJECT(bus), name, NULL); object_unref(OBJECT(kid->child)); @@ -73,6 +75,7 @@ static void bus_add_child(BusState *bus, DeviceState *child) char name[32]; BusChild *kid = g_malloc0(sizeof(*kid)); + bus->num_children++; kid->index = bus->max_index++; kid->child = child; object_ref(OBJECT(kid->child)); diff --git a/qdev-monitor.c b/qdev-monitor.c index 07147c63bf..45a8ba4964 100644 --- a/qdev-monitor.c +++ b/qdev-monitor.c @@ -414,7 +414,7 @@ static DeviceState *qbus_find_dev(BusState *bus, char *elem) static inline bool qbus_is_full(BusState *bus) { BusClass *bus_class = BUS_GET_CLASS(bus); - return bus_class->max_dev && bus->max_index >= bus_class->max_dev; + return bus_class->max_dev && bus->num_children >= bus_class->max_dev; } /*