From patchwork Sun Aug 19 23:22:39 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Sven Eckelmann X-Patchwork-Id: 2243 Return-Path: Received: from v3-1039.vlinux.de (narfation.org [79.140.41.39]) by open-mesh.org (Postfix) with ESMTPS id BA5F56008CE for ; Mon, 20 Aug 2012 01:22:44 +0200 (CEST) Authentication-Results: open-mesh.org; dkim=pass reason="1024-bit key; insecure key" header.i=@narfation.org header.b=zOS9fQ2R; dkim-adsp=pass; dkim-atps=neutral Received: from sven-desktop.home.narfation.org (unknown [78.134.85.115]) by v3-1039.vlinux.de (Postfix) with ESMTPSA id 2E284940A0; Mon, 20 Aug 2012 01:22:44 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=narfation.org; s=20121; t=1345418564; bh=doUHRp9INXfCHkKCuszbD5nRC1+EtzA7n5EQGdhvR3c=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=zOS9fQ2RDW7IDPh8PEfylukycsowapE83NjysoLfD+bsbnOtv2GA1WnYOs3q+rIyA sKEV+2/rvW0L5Li+37d5CHlxAjfD60IWc6NbrPOUJYGdFt+FAN6vvTDTZtw9VYESbv 6iWQZHTdSGrUQ0056hr3WERveU3whrbub2meSiLQ= From: Sven Eckelmann To: b.a.t.m.a.n@lists.open-mesh.org Date: Mon, 20 Aug 2012 01:22:39 +0200 Message-Id: <1345418559-27150-1-git-send-email-sven@narfation.org> X-Mailer: git-send-email 1.7.10.4 In-Reply-To: <1345361393-8759-1-git-send-email-sven@narfation.org> References: <1345361393-8759-1-git-send-email-sven@narfation.org> MIME-Version: 1.0 Subject: [B.A.T.M.A.N.] [PATCH] batman-adv: Set special lockdep classes to avoid lockdep warning X-BeenThere: b.a.t.m.a.n@lists.open-mesh.org X-Mailman-Version: 2.1.15 Precedence: list Reply-To: The list for a Better Approach To Mobile Ad-hoc Networking List-Id: The list for a Better Approach To Mobile Ad-hoc Networking List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 19 Aug 2012 23:22:44 -0000 Transmissions over batman-adv devices always start another nested transmission over devices attached to the batman-adv interface. These devices usually use the ethernet lockdep class for the tx_queue lock which is also set by default for all batman-adv devices. Lockdep will detect a nested locking attempt of two locks with the same class and warn about a possible deadlock. This is the default and expected behavior and should not alarm the locking correctness prove mechanism. Therefore, the locks for all netdevice specific lock get a special batman-adv lock class to avoid a false positive for each transmission. Reported-by: Linus Lüssing Signed-off-by: Sven Eckelmann --- soft-interface.c | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+) diff --git a/soft-interface.c b/soft-interface.c index 1aee7db..513d50a 100644 --- a/soft-interface.c +++ b/soft-interface.c @@ -354,6 +354,27 @@ static const struct net_device_ops batadv_netdev_ops = { .ndo_validate_addr = eth_validate_addr }; +/* + * batman-adv network devices have devices nesting below it and are a special + * "super class" of normal network devices; split their locks off into a + * separate class since they always nest. + */ +static struct lock_class_key batadv_netdev_xmit_lock_key; +static struct lock_class_key batadv_netdev_addr_lock_key; + +static void batadv_set_lockdep_class_one(struct net_device *dev, + struct netdev_queue *txq, + void *_unused) +{ + lockdep_set_class(&txq->_xmit_lock, &batadv_netdev_xmit_lock_key); +} + +static void batadv_set_lockdep_class(struct net_device *dev) +{ + lockdep_set_class(&dev->addr_list_lock, &batadv_netdev_addr_lock_key); + netdev_for_each_tx_queue(dev, batadv_set_lockdep_class_one, NULL); +} + static void batadv_interface_setup(struct net_device *dev) { struct batadv_priv *priv = netdev_priv(dev); @@ -363,6 +384,7 @@ static void batadv_interface_setup(struct net_device *dev) dev->netdev_ops = &batadv_netdev_ops; dev->destructor = free_netdev; dev->tx_queue_len = 0; + batadv_set_lockdep_class(dev); /* can't call min_mtu, because the needed variables * have not been initialized yet