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mac80211: add ieee80211_iterate_active_interfaces_rtnl()

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If it is needed to disconnect multiple virtual interfaces after
(WoWLAN-) suspend, the most obvious approach would be to iterate
all interfaces by calling ieee80211_iterate_active_interfaces()
and then call ieee80211_resume_disconnect() for each one. This
is what the iwlmvm driver does.

Unfortunately, this causes a locking dependency from mac80211's
iflist_mtx to the key_mtx. This is problematic as the former is
intentionally never held while calling any driver operation to
allow drivers to iterate with their own locks held. The key_mtx
is held while installing a key into the driver though, so this
new lock dependency means drivers implementing the logic above
can no longer hold their own lock while iterating.

To fix this, add a new ieee80211_iterate_active_interfaces_rtnl()
function that iterates while the RTNL is already held. This is
true during suspend/resume, so that then the locking dependency
isn't introduced.

While at it, also refactor the various interface iterators and
keep only a single implementation called by the various cases.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
This commit is contained in:
Johannes Berg 2013-08-21 22:07:20 +02:00
parent 272b98c645
commit c7c71066c2
2 changed files with 66 additions and 50 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

19
include/net/mac80211.h
View file

@ -3919,6 +3919,25 @@ void ieee80211_iterate_active_interfaces_atomic(struct ieee80211_hw *hw,
struct ieee80211_vif *vif),
void *data);
/**
* ieee80211_iterate_active_interfaces_rtnl - iterate active interfaces
*
* This function iterates over the interfaces associated with a given
* hardware that are currently active and calls the callback for them.
* This version can only be used while holding the RTNL.
*
* @hw: the hardware struct of which the interfaces should be iterated over
* @iter_flags: iteration flags, see &enum ieee80211_interface_iteration_flags
* @iterator: the iterator function to call, cannot sleep
* @data: first argument of the iterator function
*/
void ieee80211_iterate_active_interfaces_rtnl(struct ieee80211_hw *hw,
u32 iter_flags,
void (*iterator)(void *data,
u8 *mac,
struct ieee80211_vif *vif),
void *data);
/**
* ieee80211_queue_work - add work onto the mac80211 workqueue
*

97
net/mac80211/util.c
View file

@ -567,58 +567,14 @@ void ieee80211_flush_queues(struct ieee80211_local *local,
IEEE80211_QUEUE_STOP_REASON_FLUSH);
}
void ieee80211_iterate_active_interfaces(
struct ieee80211_hw *hw, u32 iter_flags,
void (*iterator)(void *data, u8 *mac,
struct ieee80211_vif *vif),
void *data)
static void __iterate_active_interfaces(struct ieee80211_local *local,
u32 iter_flags,
void (*iterator)(void *data, u8 *mac,
struct ieee80211_vif *vif),
void *data)
{
struct ieee80211_local *local = hw_to_local(hw);
struct ieee80211_sub_if_data *sdata;
mutex_lock(&local->iflist_mtx);
list_for_each_entry(sdata, &local->interfaces, list) {
switch (sdata->vif.type) {
case NL80211_IFTYPE_MONITOR:
if (!(sdata->u.mntr_flags & MONITOR_FLAG_ACTIVE))
continue;
break;
case NL80211_IFTYPE_AP_VLAN:
continue;
default:
break;
}
if (!(iter_flags & IEEE80211_IFACE_ITER_RESUME_ALL) &&
!(sdata->flags & IEEE80211_SDATA_IN_DRIVER))
continue;
if (ieee80211_sdata_running(sdata))
iterator(data, sdata->vif.addr,
&sdata->vif);
}
sdata = rcu_dereference_protected(local->monitor_sdata,
lockdep_is_held(&local->iflist_mtx));
if (sdata &&
(iter_flags & IEEE80211_IFACE_ITER_RESUME_ALL ||
sdata->flags & IEEE80211_SDATA_IN_DRIVER))
iterator(data, sdata->vif.addr, &sdata->vif);
mutex_unlock(&local->iflist_mtx);
}
EXPORT_SYMBOL_GPL(ieee80211_iterate_active_interfaces);
void ieee80211_iterate_active_interfaces_atomic(
struct ieee80211_hw *hw, u32 iter_flags,
void (*iterator)(void *data, u8 *mac,
struct ieee80211_vif *vif),
void *data)
{
struct ieee80211_local *local = hw_to_local(hw);
struct ieee80211_sub_if_data *sdata;
rcu_read_lock();
list_for_each_entry_rcu(sdata, &local->interfaces, list) {
switch (sdata->vif.type) {
case NL80211_IFTYPE_MONITOR:
@ -638,16 +594,57 @@ void ieee80211_iterate_active_interfaces_atomic(
&sdata->vif);
}
sdata = rcu_dereference(local->monitor_sdata);
sdata = rcu_dereference_check(local->monitor_sdata,
lockdep_is_held(&local->iflist_mtx) ||
lockdep_rtnl_is_held());
if (sdata &&
(iter_flags & IEEE80211_IFACE_ITER_RESUME_ALL ||
sdata->flags & IEEE80211_SDATA_IN_DRIVER))
iterator(data, sdata->vif.addr, &sdata->vif);
}
void ieee80211_iterate_active_interfaces(
struct ieee80211_hw *hw, u32 iter_flags,
void (*iterator)(void *data, u8 *mac,
struct ieee80211_vif *vif),
void *data)
{
struct ieee80211_local *local = hw_to_local(hw);
mutex_lock(&local->iflist_mtx);
__iterate_active_interfaces(local, iter_flags, iterator, data);
mutex_unlock(&local->iflist_mtx);
}
EXPORT_SYMBOL_GPL(ieee80211_iterate_active_interfaces);
void ieee80211_iterate_active_interfaces_atomic(
struct ieee80211_hw *hw, u32 iter_flags,
void (*iterator)(void *data, u8 *mac,
struct ieee80211_vif *vif),
void *data)
{
struct ieee80211_local *local = hw_to_local(hw);
rcu_read_lock();
__iterate_active_interfaces(local, iter_flags, iterator, data);
rcu_read_unlock();
}
EXPORT_SYMBOL_GPL(ieee80211_iterate_active_interfaces_atomic);
void ieee80211_iterate_active_interfaces_rtnl(
struct ieee80211_hw *hw, u32 iter_flags,
void (*iterator)(void *data, u8 *mac,
struct ieee80211_vif *vif),
void *data)
{
struct ieee80211_local *local = hw_to_local(hw);
ASSERT_RTNL();
__iterate_active_interfaces(local, iter_flags, iterator, data);
}
EXPORT_SYMBOL_GPL(ieee80211_iterate_active_interfaces_rtnl);
/*
* Nothing should have been stuffed into the workqueue during
* the suspend->resume cycle. If this WARN is seen then there