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mac80211: explicitly copy channels to VLANs where needed

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Currently the code assigns channel contexts to VLANs
(for use by the TX/RX code) when the AP master gets
its channel context assigned. This works fine, but
in the upcoming radar detection work the VLANs don't
require a channel context (during radar detection)
and assigning one to them anyway causes issues with
locking and also inconsistencies -- a VLAN interface
that is added before radar detection would get the
channel context, while one added during it wouldn't.

Fix these issues moving the channel context copying
to a new explicit operation that will not be used
in the radar detection code.

Acked-by: Simon Wunderlich <siwu@hrz.tu-chemnitz.de>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
This commit is contained in:
Johannes Berg 2013-02-08 12:07:44 +01:00
parent 757af6fefd
commit 1f4ac5a63f
3 changed files with 38 additions and 18 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
net/mac80211/cfg.c
View File

@ -933,6 +933,7 @@ static int ieee80211_start_ap(struct wiphy *wiphy, struct net_device *dev,
IEEE80211_CHANCTX_SHARED);
if (err)
return err;
ieee80211_vif_copy_chanctx_to_vlans(sdata, false);
/*
* Apply control port protocol, this allows us to
@ -1047,6 +1048,7 @@ static int ieee80211_stop_ap(struct wiphy *wiphy, struct net_device *dev)
local->total_ps_buffered -= skb_queue_len(&sdata->u.ap.ps.bc_buf);
skb_queue_purge(&sdata->u.ap.ps.bc_buf);
ieee80211_vif_copy_chanctx_to_vlans(sdata, true);
ieee80211_vif_release_channel(sdata);
return 0;

52
net/mac80211/chan.c
View File

@ -198,15 +198,6 @@ static void __ieee80211_vif_release_channel(struct ieee80211_sub_if_data *sdata)
ctx = container_of(conf, struct ieee80211_chanctx, conf);
if (sdata->vif.type == NL80211_IFTYPE_AP) {
struct ieee80211_sub_if_data *vlan;
/* for the VLAN list */
ASSERT_RTNL();
list_for_each_entry(vlan, &sdata->u.ap.vlans, u.vlan.list)
rcu_assign_pointer(vlan->vif.chanctx_conf, NULL);
}
ieee80211_unassign_vif_chanctx(sdata, ctx);
if (ctx->refcount == 0)
ieee80211_free_chanctx(local, ctx);
@ -326,15 +317,6 @@ int ieee80211_vif_use_channel(struct ieee80211_sub_if_data *sdata,
goto out;
}
if (sdata->vif.type == NL80211_IFTYPE_AP) {
struct ieee80211_sub_if_data *vlan;
/* for the VLAN list */
ASSERT_RTNL();
list_for_each_entry(vlan, &sdata->u.ap.vlans, u.vlan.list)
rcu_assign_pointer(vlan->vif.chanctx_conf, &ctx->conf);
}
ieee80211_recalc_smps_chanctx(local, ctx);
out:
mutex_unlock(&local->chanctx_mtx);
@ -369,6 +351,40 @@ void ieee80211_vif_vlan_copy_chanctx(struct ieee80211_sub_if_data *sdata)
mutex_unlock(&local->chanctx_mtx);
}
void ieee80211_vif_copy_chanctx_to_vlans(struct ieee80211_sub_if_data *sdata,
bool clear)
{
struct ieee80211_local *local = sdata->local;
struct ieee80211_sub_if_data *vlan;
struct ieee80211_chanctx_conf *conf;
ASSERT_RTNL();
if (WARN_ON(sdata->vif.type != NL80211_IFTYPE_AP))
return;
mutex_lock(&local->chanctx_mtx);
/*
* Check that conf exists, even when clearing this function
* must be called with the AP's channel context still there
* as it would otherwise cause VLANs to have an invalid
* channel context pointer for a while, possibly pointing
* to a channel context that has already been freed.
*/
conf = rcu_dereference_protected(sdata->vif.chanctx_conf,
lockdep_is_held(&local->chanctx_mtx));
WARN_ON(!conf);
if (clear)
conf = NULL;
list_for_each_entry(vlan, &sdata->u.ap.vlans, u.vlan.list)
rcu_assign_pointer(vlan->vif.chanctx_conf, conf);
mutex_unlock(&local->chanctx_mtx);
}
void ieee80211_iter_chan_contexts_atomic(
struct ieee80211_hw *hw,
void (*iter)(struct ieee80211_hw *hw,

2
net/mac80211/ieee80211_i.h
View File

@ -1605,6 +1605,8 @@ ieee80211_vif_use_channel(struct ieee80211_sub_if_data *sdata,
enum ieee80211_chanctx_mode mode);
void ieee80211_vif_release_channel(struct ieee80211_sub_if_data *sdata);
void ieee80211_vif_vlan_copy_chanctx(struct ieee80211_sub_if_data *sdata);
void ieee80211_vif_copy_chanctx_to_vlans(struct ieee80211_sub_if_data *sdata,
bool clear);
void ieee80211_recalc_smps_chanctx(struct ieee80211_local *local,
struct ieee80211_chanctx *chanctx);