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From: Sven Eckelmann <sven@narfation.org>
To: b.a.t.m.a.n@lists.open-mesh.org
Subject: [B.A.T.M.A.N.] [PATCH 3/4] batman-adv: Correct rcu refcounting for batman_if
Date: Sun, 30 Jan 2011 02:52:58 +0100	[thread overview]
Message-ID: <1296352379-1546-4-git-send-email-sven@narfation.org> (raw)
In-Reply-To: <1296352379-1546-1-git-send-email-sven@narfation.org>

<TODO: write a long monologue about every problem we have or could have or
maybe never had and would have when we not have it>

Signed-off-by: Sven Eckelmann <sven@narfation.org>
---
 batman-adv/bat_sysfs.c      |   12 ++++++------
 batman-adv/hard-interface.c |   40 +++++++++++++++++++---------------------
 batman-adv/hard-interface.h |    9 ++++-----
 batman-adv/types.h          |    2 +-
 4 files changed, 30 insertions(+), 33 deletions(-)

diff --git a/batman-adv/bat_sysfs.c b/batman-adv/bat_sysfs.c
index f7b93a0..08f9251 100644
--- a/batman-adv/bat_sysfs.c
+++ b/batman-adv/bat_sysfs.c
@@ -450,7 +450,7 @@ static ssize_t show_mesh_iface(struct kobject *kobj, struct attribute *attr,
 	length = sprintf(buff, "%s\n", batman_if->if_status == IF_NOT_IN_USE ?
 			 "none" : batman_if->soft_iface->name);
 
-	kref_put(&batman_if->refcount, hardif_free_ref);
+	hardif_free_ref(batman_if);
 
 	return length;
 }
@@ -472,7 +472,7 @@ static ssize_t store_mesh_iface(struct kobject *kobj, struct attribute *attr,
 	if (strlen(buff) >= IFNAMSIZ) {
 		pr_err("Invalid parameter for 'mesh_iface' setting received: "
 		       "interface name too long '%s'\n", buff);
-		kref_put(&batman_if->refcount, hardif_free_ref);
+		hardif_free_ref(batman_if);
 		return -EINVAL;
 	}
 
@@ -483,7 +483,7 @@ static ssize_t store_mesh_iface(struct kobject *kobj, struct attribute *attr,
 
 	if ((batman_if->if_status == status_tmp) || ((batman_if->soft_iface) &&
 	    (strncmp(batman_if->soft_iface->name, buff, IFNAMSIZ) == 0))) {
-		kref_put(&batman_if->refcount, hardif_free_ref);
+		hardif_free_ref(batman_if);
 		return count;
 	}
 
@@ -491,7 +491,7 @@ static ssize_t store_mesh_iface(struct kobject *kobj, struct attribute *attr,
 		rtnl_lock();
 		hardif_disable_interface(batman_if);
 		rtnl_unlock();
-		kref_put(&batman_if->refcount, hardif_free_ref);
+		hardif_free_ref(batman_if);
 		return count;
 	}
 
@@ -503,7 +503,7 @@ static ssize_t store_mesh_iface(struct kobject *kobj, struct attribute *attr,
 	}
 
 	ret = hardif_enable_interface(batman_if, buff);
-	kref_put(&batman_if->refcount, hardif_free_ref);
+	hardif_free_ref(batman_if);
 
 	return ret;
 }
@@ -537,7 +537,7 @@ static ssize_t show_iface_status(struct kobject *kobj, struct attribute *attr,
 		break;
 	}
 
-	kref_put(&batman_if->refcount, hardif_free_ref);
+	hardif_free_ref(batman_if);
 
 	return length;
 }
diff --git a/batman-adv/hard-interface.c b/batman-adv/hard-interface.c
index e2b001a..3f59c52 100644
--- a/batman-adv/hard-interface.c
+++ b/batman-adv/hard-interface.c
@@ -40,13 +40,13 @@ static int batman_skb_recv(struct sk_buff *skb,
 			   struct packet_type *ptype,
 			   struct net_device *orig_dev);
 
-static void hardif_free_rcu(struct rcu_head *rcu)
+void hardif_free_rcu(struct rcu_head *rcu)
 {
 	struct batman_if *batman_if;
 
 	batman_if = container_of(rcu, struct batman_if, rcu);
 	dev_put(batman_if->net_dev);
-	kref_put(&batman_if->refcount, hardif_free_ref);
+	kfree(batman_if);
 }
 
 struct batman_if *get_batman_if_by_netdev(struct net_device *net_dev)
@@ -55,16 +55,14 @@ struct batman_if *get_batman_if_by_netdev(struct net_device *net_dev)
 
 	rcu_read_lock();
 	list_for_each_entry_rcu(batman_if, &if_list, list) {
-		if (batman_if->net_dev == net_dev)
+		if (batman_if->net_dev == net_dev &&
+		    atomic_inc_not_zero(&batman_if->refcount))
 			goto out;
 	}
 
 	batman_if = NULL;
 
 out:
-	if (batman_if)
-		kref_get(&batman_if->refcount);
-
 	rcu_read_unlock();
 	return batman_if;
 }
@@ -105,16 +103,14 @@ static struct batman_if *get_active_batman_if(struct net_device *soft_iface)
 		if (batman_if->soft_iface != soft_iface)
 			continue;
 
-		if (batman_if->if_status == IF_ACTIVE)
+		if (batman_if->if_status == IF_ACTIVE &&
+		    atomic_inc_not_zero(&batman_if->refcount))
 			goto out;
 	}
 
 	batman_if = NULL;
 
 out:
-	if (batman_if)
-		kref_get(&batman_if->refcount);
-
 	rcu_read_unlock();
 	return batman_if;
 }
@@ -137,14 +133,14 @@ static void set_primary_if(struct bat_priv *bat_priv,
 	struct batman_packet *batman_packet;
 	struct batman_if *old_if;
 
-	if (batman_if)
-		kref_get(&batman_if->refcount);
+	if (batman_if && !atomic_inc_not_zero(&batman_if->refcount))
+		batman_if = NULL;
 
 	old_if = bat_priv->primary_if;
 	bat_priv->primary_if = batman_if;
 
 	if (old_if)
-		kref_put(&old_if->refcount, hardif_free_ref);
+		hardif_free_ref(old_if);
 
 	if (!bat_priv->primary_if)
 		return;
@@ -290,6 +286,9 @@ int hardif_enable_interface(struct batman_if *batman_if, char *iface_name)
 	if (batman_if->if_status != IF_NOT_IN_USE)
 		goto out;
 
+	if (!atomic_inc_not_zero(&batman_if->refcount))
+		goto out;
+
 	batman_if->soft_iface = dev_get_by_name(&init_net, iface_name);
 
 	if (!batman_if->soft_iface) {
@@ -328,7 +327,6 @@ int hardif_enable_interface(struct batman_if *batman_if, char *iface_name)
 	batman_if->batman_adv_ptype.type = __constant_htons(ETH_P_BATMAN);
 	batman_if->batman_adv_ptype.func = batman_skb_recv;
 	batman_if->batman_adv_ptype.dev = batman_if->net_dev;
-	kref_get(&batman_if->refcount);
 	dev_add_pack(&batman_if->batman_adv_ptype);
 
 	atomic_set(&batman_if->seqno, 1);
@@ -371,6 +369,7 @@ out:
 	return 0;
 
 err:
+	hardif_free_ref(batman_if);
 	return -ENOMEM;
 }
 
@@ -387,7 +386,7 @@ void hardif_disable_interface(struct batman_if *batman_if)
 	bat_info(batman_if->soft_iface, "Removing interface: %s\n",
 		 batman_if->net_dev->name);
 	dev_remove_pack(&batman_if->batman_adv_ptype);
-	kref_put(&batman_if->refcount, hardif_free_ref);
+	hardif_free_ref(batman_if);
 
 	bat_priv->num_ifaces--;
 	orig_hash_del_if(batman_if, bat_priv->num_ifaces);
@@ -399,7 +398,7 @@ void hardif_disable_interface(struct batman_if *batman_if)
 		set_primary_if(bat_priv, new_if);
 
 		if (new_if)
-			kref_put(&new_if->refcount, hardif_free_ref);
+			hardif_free_ref(new_if);
 	}
 
 	kfree(batman_if->packet_buff);
@@ -445,7 +444,8 @@ static struct batman_if *hardif_add_interface(struct net_device *net_dev)
 	batman_if->soft_iface = NULL;
 	batman_if->if_status = IF_NOT_IN_USE;
 	INIT_LIST_HEAD(&batman_if->list);
-	kref_init(&batman_if->refcount);
+	/* extra reference for return */
+	atomic_set(&batman_if->refcount, 2);
 
 	check_known_mac_addr(batman_if->net_dev);
 
@@ -453,8 +453,6 @@ static struct batman_if *hardif_add_interface(struct net_device *net_dev)
 	list_add_tail_rcu(&batman_if->list, &if_list);
 	spin_unlock(&if_list_lock);
 
-	/* extra reference for return */
-	kref_get(&batman_if->refcount);
 	return batman_if;
 
 free_if:
@@ -476,7 +474,7 @@ static void hardif_remove_interface(struct batman_if *batman_if)
 
 	batman_if->if_status = IF_TO_BE_REMOVED;
 	sysfs_del_hardif(&batman_if->hardif_obj);
-	call_rcu(&batman_if->rcu, hardif_free_rcu);
+	hardif_free_ref(batman_if);
 }
 
 void hardif_remove_interfaces(void)
@@ -548,7 +546,7 @@ static int hard_if_event(struct notifier_block *this,
 	};
 
 hardif_put:
-	kref_put(&batman_if->refcount, hardif_free_ref);
+	hardif_free_ref(batman_if);
 out:
 	return NOTIFY_DONE;
 }
diff --git a/batman-adv/hard-interface.h b/batman-adv/hard-interface.h
index ad19543..e488b90 100644
--- a/batman-adv/hard-interface.h
+++ b/batman-adv/hard-interface.h
@@ -37,13 +37,12 @@ void hardif_disable_interface(struct batman_if *batman_if);
 void hardif_remove_interfaces(void);
 int hardif_min_mtu(struct net_device *soft_iface);
 void update_min_mtu(struct net_device *soft_iface);
+void hardif_free_rcu(struct rcu_head *rcu);
 
-static inline void hardif_free_ref(struct kref *refcount)
+static inline void hardif_free_ref(struct batman_if *batman_if)
 {
-	struct batman_if *batman_if;
-
-	batman_if = container_of(refcount, struct batman_if, refcount);
-	kfree(batman_if);
+	if (atomic_dec_and_test(&batman_if->refcount))
+		call_rcu(&batman_if->rcu, hardif_free_rcu);
 }
 
 #endif /* _NET_BATMAN_ADV_HARD_INTERFACE_H_ */
diff --git a/batman-adv/types.h b/batman-adv/types.h
index 8df6d9d..317ede8 100644
--- a/batman-adv/types.h
+++ b/batman-adv/types.h
@@ -43,7 +43,7 @@ struct batman_if {
 	unsigned char *packet_buff;
 	int packet_len;
 	struct kobject *hardif_obj;
-	struct kref refcount;
+	atomic_t refcount;
 	struct packet_type batman_adv_ptype;
 	struct net_device *soft_iface;
 	struct rcu_head rcu;
-- 
1.7.2.3


  parent reply	other threads:[~2011-01-30  1:52 UTC|newest]

Thread overview: 44+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-01-30  1:52 [B.A.T.M.A.N.] Reordered rcu refcounting Sven Eckelmann
2011-01-30  1:52 ` [B.A.T.M.A.N.] [PATCH 1/4] batman-adv: Correct rcu refcounting for gw_node Sven Eckelmann
2011-02-02 17:37   ` [B.A.T.M.A.N.] [PATCH] " Linus Lüssing
2011-02-02 19:49     ` Marek Lindner
2011-02-02 20:43       ` Linus Lüssing
2011-02-02 21:42     ` Sven Eckelmann
2011-02-03  0:19       ` Marek Lindner
2011-02-03  9:55       ` Linus Lüssing
2011-02-03 10:01         ` Sven Eckelmann
2011-02-03 14:43     ` [B.A.T.M.A.N.] [PATCH 1/3] " Linus Lüssing
2011-02-03 17:56       ` Sven Eckelmann
2011-02-03 14:43     ` [B.A.T.M.A.N.] [PATCH 2/3] batman-adv: add __rcu annotations " Linus Lüssing
2011-02-03 14:43     ` [B.A.T.M.A.N.] [PATCH 3/3] batman-adv: Increase orig_node refcount before releasing rcu read lock Linus Lüssing
2011-01-30  1:52 ` [B.A.T.M.A.N.] [PATCH 2/4] batman-adv: Correct rcu refcounting for softif_neigh Sven Eckelmann
2011-01-30  1:52 ` Sven Eckelmann [this message]
2011-01-30  1:52 ` [B.A.T.M.A.N.] [PATCH 4/4] batman-adv: Correct rcu refcounting for neigh_node Sven Eckelmann
2011-01-30 15:20   ` [B.A.T.M.A.N.] [PATCHv2 " Sven Eckelmann
2011-02-03 17:02 ` [B.A.T.M.A.N.] Reordered rcu refcounting Marek Lindner
2011-02-03 17:03   ` [B.A.T.M.A.N.] [PATCH 1/4] batman-adv: Correct rcu refcounting for gw_node Marek Lindner
2011-02-03 17:03   ` [B.A.T.M.A.N.] [PATCH 2/4] batman-adv: Correct rcu refcounting for softif_neigh Marek Lindner
2011-02-03 17:03   ` [B.A.T.M.A.N.] [PATCH 3/4] batman-adv: Correct rcu refcounting for batman_if Marek Lindner
2011-02-03 17:03   ` [B.A.T.M.A.N.] [PATCH 4/4] batman-adv: Correct rcu refcounting for neigh_node Marek Lindner
2011-02-04 12:59     ` [B.A.T.M.A.N.] [PATCHv2 " Marek Lindner
2011-02-04 15:21   ` [B.A.T.M.A.N.] Reordered rcu refcounting, v3 Linus Lüssing
2011-02-04 15:21   ` [B.A.T.M.A.N.] [PATCH 1/7] batman-adv: Correct rcu refcounting for gw_node Linus Lüssing
2011-02-10 11:01     ` Linus Lüssing
2011-02-04 15:21   ` [B.A.T.M.A.N.] [PATCH 2/7] batman-adv: Correct rcu refcounting for softif_neigh Linus Lüssing
2011-02-10 12:45     ` Linus Lüssing
2011-02-10 13:57       ` Marek Lindner
2011-02-12 21:23         ` Linus Lüssing
2011-02-04 15:21   ` [B.A.T.M.A.N.] [PATCH 3/7] batman-adv: Correct rcu refcounting for batman_if Linus Lüssing
2011-02-04 15:21   ` [B.A.T.M.A.N.] [PATCH 4/7] batman-adv: Correct rcu refcounting for neigh_node Linus Lüssing
2011-02-04 15:21   ` [B.A.T.M.A.N.] [PATCH 5/7] batman-adv: Make bat_priv->curr_gw an rcu protected pointer Linus Lüssing
2011-02-08 13:18     ` Marek Lindner
2011-02-10 10:42       ` Linus Lüssing
2011-02-10 14:25         ` Marek Lindner
2011-02-12 21:21           ` Linus Lüssing
2011-02-12 21:21           ` [B.A.T.M.A.N.] [PATCHv2 " Linus Lüssing
2011-02-13 21:09             ` Marek Lindner
2011-02-04 15:21   ` [B.A.T.M.A.N.] [PATCH 6/7] batman-adv: add __rcu annotations for gw_node Linus Lüssing
2011-02-13 21:10     ` Marek Lindner
2011-02-04 15:21   ` [B.A.T.M.A.N.] [PATCH 7/7] batman-adv: Increase orig_node refcount before releasing rcu read lock Linus Lüssing
2011-02-04 16:33     ` [B.A.T.M.A.N.] [PATCHv2 " Linus Lüssing
2011-02-13 21:11     ` [B.A.T.M.A.N.] [PATCH " Marek Lindner

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