From patchwork Mon May 2 19:19:37 2011 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Sven Eckelmann X-Patchwork-Id: 1009 Return-Path: Received: from v3-1039.vlinux.de (narfation.org [79.140.41.39]) by open-mesh.org (Postfix) with ESMTPS id 0B424154214 for ; Mon, 2 May 2011 21:19:43 +0200 (CEST) Authentication-Results: open-mesh.org; dkim=pass (1024-bit key) header.i=@narfation.org; dkim-adsp=pass Received: from sven-desktop.home.narfation.org (i59F6B6B2.versanet.de [89.246.182.178]) by v3-1039.vlinux.de (Postfix) with ESMTPSA id F18FA940CF; Mon, 2 May 2011 21:19:54 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=narfation.org; s=mail; t=1304363995; bh=RbfOIWnh9SsXd82OYCt0jEoBmkkc/zzpNB8HEqcW89M=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version:Content-Type: Content-Transfer-Encoding; b=r75AE3Y3JaPko8anwY7sJFDKno1oX+R2GKqjp0eR64QvZwBtxbqEG8ni4l/vgg2nm PqGILXha8tIJkQpLnEmrLHbDKajmgGE7DsxxMgzGFlyRDJNecvKzl99QAvdo5RfyR2 8zng/vCH9XZCML9GHFcigfKghgDS5NVmarIkjO6M= From: Sven Eckelmann To: b.a.t.m.a.n@lists.open-mesh.org Date: Mon, 2 May 2011 21:19:37 +0200 Message-Id: <1304363978-16164-1-git-send-email-sven@narfation.org> X-Mailer: git-send-email 1.7.4.4 MIME-Version: 1.0 Subject: [B.A.T.M.A.N.] [PATCHv4 1/2] batman-adv: Remove unnecessary hardif_list_lock X-BeenThere: b.a.t.m.a.n@lists.open-mesh.org X-Mailman-Version: 2.1.13 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: Mon, 02 May 2011 19:19:43 -0000 hardif_list_lock is unneccessary because we already ensure that no multiple admin operations can take place through rtnl_lock. hardif_list_lock only adds additional overhead and complexity. Critical functions now check whether they are called with rtnl_lock using ASSERT_RTNL. It indirectly fixes the problem that orig_hash_del_if() expects that only one interface is deleted from hardif_list at a time, but hardif_remove_interfaces() removes all at once and then calls orig_hash_del_if(). Reported-by: Linus Lüssing Signed-off-by: Sven Eckelmann --- Addressed Linus' comments: * Merged patch 1/3 and 2/3 again * Ensure that primary_if_select is only called with rtnl_lock through hardif_enable_interface (was fixed in patch 3/3... but now in a patch earlier) * Add a comment above hardif_list to inform about needed locking bat_sysfs.c | 2 ++ hard-interface.c | 30 +++++++----------------------- main.c | 3 +++ 3 files changed, 12 insertions(+), 23 deletions(-) diff --git a/bat_sysfs.c b/bat_sysfs.c index e449bf6..85ba20d 100644 --- a/bat_sysfs.c +++ b/bat_sysfs.c @@ -502,7 +502,9 @@ static ssize_t store_mesh_iface(struct kobject *kobj, struct attribute *attr, rtnl_unlock(); } + rtnl_lock(); ret = hardif_enable_interface(hard_iface, buff); + rtnl_unlock(); out: hardif_free_ref(hard_iface); diff --git a/hard-interface.c b/hard-interface.c index 3e888f1..7e2f772 100644 --- a/hard-interface.c +++ b/hard-interface.c @@ -31,9 +31,6 @@ #include -/* protect update critical side of hardif_list - but not the content */ -static DEFINE_SPINLOCK(hardif_list_lock); - static int batman_skb_recv(struct sk_buff *skb, struct net_device *dev, @@ -136,7 +133,7 @@ static void primary_if_select(struct bat_priv *bat_priv, struct hard_iface *curr_hard_iface; struct batman_packet *batman_packet; - spin_lock_bh(&hardif_list_lock); + ASSERT_RTNL(); if (new_hard_iface && !atomic_inc_not_zero(&new_hard_iface->refcount)) new_hard_iface = NULL; @@ -148,7 +145,7 @@ static void primary_if_select(struct bat_priv *bat_priv, hardif_free_ref(curr_hard_iface); if (!new_hard_iface) - goto out; + return; batman_packet = (struct batman_packet *)(new_hard_iface->packet_buff); batman_packet->flags = PRIMARIES_FIRST_HOP; @@ -161,9 +158,6 @@ static void primary_if_select(struct bat_priv *bat_priv, * our new primary interface */ atomic_set(&bat_priv->hna_local_changed, 1); - -out: - spin_unlock_bh(&hardif_list_lock); } static bool hardif_is_iface_up(struct hard_iface *hard_iface) @@ -456,6 +450,8 @@ static struct hard_iface *hardif_add_interface(struct net_device *net_dev) struct hard_iface *hard_iface; int ret; + ASSERT_RTNL(); + ret = is_valid_iface(net_dev); if (ret != 1) goto out; @@ -482,10 +478,7 @@ static struct hard_iface *hardif_add_interface(struct net_device *net_dev) atomic_set(&hard_iface->refcount, 2); check_known_mac_addr(hard_iface->net_dev); - - spin_lock(&hardif_list_lock); list_add_tail_rcu(&hard_iface->list, &hardif_list); - spin_unlock(&hardif_list_lock); return hard_iface; @@ -499,6 +492,8 @@ out: static void hardif_remove_interface(struct hard_iface *hard_iface) { + ASSERT_RTNL(); + /* first deactivate interface */ if (hard_iface->if_status != IF_NOT_IN_USE) hardif_disable_interface(hard_iface); @@ -514,20 +509,11 @@ static void hardif_remove_interface(struct hard_iface *hard_iface) void hardif_remove_interfaces(void) { struct hard_iface *hard_iface, *hard_iface_tmp; - struct list_head if_queue; - INIT_LIST_HEAD(&if_queue); - - spin_lock(&hardif_list_lock); + rtnl_lock(); list_for_each_entry_safe(hard_iface, hard_iface_tmp, &hardif_list, list) { list_del_rcu(&hard_iface->list); - list_add_tail(&hard_iface->list, &if_queue); - } - spin_unlock(&hardif_list_lock); - - rtnl_lock(); - list_for_each_entry_safe(hard_iface, hard_iface_tmp, &if_queue, list) { hardif_remove_interface(hard_iface); } rtnl_unlock(); @@ -556,9 +542,7 @@ static int hard_if_event(struct notifier_block *this, hardif_deactivate_interface(hard_iface); break; case NETDEV_UNREGISTER: - spin_lock(&hardif_list_lock); list_del_rcu(&hard_iface->list); - spin_unlock(&hardif_list_lock); hardif_remove_interface(hard_iface); break; diff --git a/main.c b/main.c index 709b33b..39feb5a 100644 --- a/main.c +++ b/main.c @@ -33,6 +33,9 @@ #include "vis.h" #include "hash.h" + +/* List manipulations on hardif_list have to be rtnl_lock()'ed, + * list traversals just rcu-locked */ struct list_head hardif_list; unsigned char broadcast_addr[] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};