diff options
| author | Sven Eckelmann | 2010-09-18 21:01:15 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman | 2010-09-21 01:29:49 +0200 |
| commit | af2ac7bfec4176cad5e04402d116b5242d759bf8 (patch) | |
| tree | 444bf4077836e828c8d882ddf7c06ef17b136a38 /drivers/staging | |
| parent | Staging: batman-adv: wait for call_rcu before unloading module (diff) | |
| download | kernel-qcow2-linux-af2ac7bfec4176cad5e04402d116b5242d759bf8.tar.gz kernel-qcow2-linux-af2ac7bfec4176cad5e04402d116b5242d759bf8.tar.xz kernel-qcow2-linux-af2ac7bfec4176cad5e04402d116b5242d759bf8.zip | |
Staging: batman-adv: Introduce if_list_lock to protect if_list
The update critical sections of if_list must be protected by a locking
primitive other than RCU. The iterator must also be protected by the
chosen locking mechanism.
The rtnl_lock in hardif_remove_interfaces must also be moved outside the
iterator primitive to ensure that we don't deadlock the kernel due to
differently nested locks in hardif_remove_interfaces and hard_if_event.
Signed-off-by: Sven Eckelmann <sven.eckelmann@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'drivers/staging')
| -rw-r--r-- | drivers/staging/batman-adv/hard-interface.c | 17 |
1 files changed, 15 insertions, 2 deletions
diff --git a/drivers/staging/batman-adv/hard-interface.c b/drivers/staging/batman-adv/hard-interface.c index a587da9c827e..35b198c6bad5 100644 --- a/drivers/staging/batman-adv/hard-interface.c +++ b/drivers/staging/batman-adv/hard-interface.c @@ -33,6 +33,9 @@ #define MIN(x, y) ((x) < (y) ? (x) : (y)) +/* protect update critical side of if_list - but not the content */ +static DEFINE_SPINLOCK(if_list_lock); + struct batman_if *get_batman_if_by_netdev(struct net_device *net_dev) { struct batman_if *batman_if; @@ -400,7 +403,11 @@ static struct batman_if *hardif_add_interface(struct net_device *net_dev) INIT_LIST_HEAD(&batman_if->list); check_known_mac_addr(batman_if->net_dev->dev_addr); + + spin_lock(&if_list_lock); list_add_tail_rcu(&batman_if->list, &if_list); + spin_unlock(&if_list_lock); + return batman_if; free_if: @@ -428,6 +435,8 @@ 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); sysfs_del_hardif(&batman_if->hardif_obj); dev_put(batman_if->net_dev); @@ -438,11 +447,13 @@ void hardif_remove_interfaces(void) { struct batman_if *batman_if, *batman_if_tmp; + rtnl_lock(); + spin_lock(&if_list_lock); list_for_each_entry_safe(batman_if, batman_if_tmp, &if_list, list) { - rtnl_lock(); hardif_remove_interface(batman_if); - rtnl_unlock(); } + spin_unlock(&if_list_lock); + rtnl_unlock(); } static int hard_if_event(struct notifier_block *this, @@ -467,7 +478,9 @@ static int hard_if_event(struct notifier_block *this, hardif_deactivate_interface(batman_if); break; case NETDEV_UNREGISTER: + spin_lock(&if_list_lock); hardif_remove_interface(batman_if); + spin_unlock(&if_list_lock); break; case NETDEV_CHANGEMTU: if (batman_if->soft_iface) |