We call a lot of the netdevice code when holding if_list_lock which will spin the whole time. This is not necessary because we only want to protect the access to the list to be serialized. An extra queue can be used which hold all interfaces which should be removed and then use that queue without any locks for netdevice cleanup.
Reported-by: Rafal Lesniak lesniak@eresi-project.org Signed-off-by: Sven Eckelmann sven.eckelmann@gmx.de --- drivers/staging/batman-adv/hard-interface.c | 19 +++++++++++++------ 1 files changed, 13 insertions(+), 6 deletions(-)
diff --git a/drivers/staging/batman-adv/hard-interface.c b/drivers/staging/batman-adv/hard-interface.c index b68a7e5..d85de82 100644 --- a/drivers/staging/batman-adv/hard-interface.c +++ b/drivers/staging/batman-adv/hard-interface.c @@ -463,9 +463,6 @@ static void hardif_remove_interface(struct batman_if *batman_if) return;
batman_if->if_status = IF_TO_BE_REMOVED; - - /* caller must take if_list_lock */ - list_del_rcu(&batman_if->list); synchronize_rcu(); sysfs_del_hardif(&batman_if->hardif_obj); hardif_put(batman_if); @@ -474,13 +471,21 @@ static void hardif_remove_interface(struct batman_if *batman_if) void hardif_remove_interfaces(void) { struct batman_if *batman_if, *batman_if_tmp; + struct list_head if_queue; + + INIT_LIST_HEAD(&if_queue);
- rtnl_lock(); spin_lock(&if_list_lock); list_for_each_entry_safe(batman_if, batman_if_tmp, &if_list, list) { - hardif_remove_interface(batman_if); + list_del_rcu(&batman_if->list); + list_add_tail(&batman_if->list, &if_queue); } spin_unlock(&if_list_lock); + + rtnl_lock(); + list_for_each_entry_safe(batman_if, batman_if_tmp, &if_queue, list) { + hardif_remove_interface(batman_if); + } rtnl_unlock(); }
@@ -507,8 +512,10 @@ static int hard_if_event(struct notifier_block *this, break; case NETDEV_UNREGISTER: spin_lock(&if_list_lock); - hardif_remove_interface(batman_if); + list_del_rcu(&batman_if->list); spin_unlock(&if_list_lock); + + hardif_remove_interface(batman_if); break; case NETDEV_CHANGEMTU: if (batman_if->soft_iface)