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.
Signed-off-by: Sven Eckelmann sven@narfation.org --- hard-interface.c | 23 +++++------------------ 1 files changed, 5 insertions(+), 18 deletions(-)
diff --git a/hard-interface.c b/hard-interface.c index b3058e4..ebd7ef0 100644 --- a/hard-interface.c +++ b/hard-interface.c @@ -31,9 +31,6 @@
#include <linux/if_arp.h>
-/* 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, @@ -432,6 +429,8 @@ 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; @@ -458,10 +457,7 @@ 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;
@@ -475,6 +471,8 @@ 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); @@ -490,20 +488,11 @@ 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(); @@ -531,9 +520,7 @@ 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;
The hard_if_event is called by the notifier with rtnl_lock and tries to remove sysfs entries when a NETDEV_UNREGISTER event is received. This will automatically take the s_active lock.
The s_active lock is also used when a new interface is added to a meshif through sysfs. In that situation we cannot wait for the rntl_lock before creating the actual batman-adv interface to prevent a deadlock. It is still possible to try to get the rtnl_lock and immediately abort the current operation when the trylock call failed.
Signed-off-by: Sven Eckelmann sven@narfation.org --- bat_sysfs.c | 13 ++++++++----- soft-interface.c | 2 +- 2 files changed, 9 insertions(+), 6 deletions(-)
diff --git a/bat_sysfs.c b/bat_sysfs.c index e449bf6..908ed5f 100644 --- a/bat_sysfs.c +++ b/bat_sysfs.c @@ -488,22 +488,25 @@ static ssize_t store_mesh_iface(struct kobject *kobj, struct attribute *attr, (strncmp(hard_iface->soft_iface->name, buff, IFNAMSIZ) == 0)) goto out;
+ if (!rtnl_trylock()) { + ret = -ERESTARTSYS; + goto out; + } + if (status_tmp == IF_NOT_IN_USE) { - rtnl_lock(); hardif_disable_interface(hard_iface); - rtnl_unlock(); - goto out; + goto unlock; }
/* if the interface already is in use */ if (hard_iface->if_status != IF_NOT_IN_USE) { - rtnl_lock(); hardif_disable_interface(hard_iface); - rtnl_unlock(); }
ret = hardif_enable_interface(hard_iface, buff);
+unlock: + rtnl_unlock(); out: hardif_free_ref(hard_iface); return ret; diff --git a/soft-interface.c b/soft-interface.c index f4d80ad..bf53aa3 100644 --- a/soft-interface.c +++ b/soft-interface.c @@ -613,7 +613,7 @@ struct net_device *softif_create(char *name) goto out; }
- ret = register_netdev(soft_iface); + ret = register_netdevice(soft_iface); if (ret < 0) { pr_err("Unable to register the batman interface '%s': %i\n", name, ret);
b.a.t.m.a.n@lists.open-mesh.org
-
Sven Eckelmann