[PATCH 3.16.y-ckt 054/144] mac80211: count interfaces correctly for combination checks

[Luis Henriques]

3.16.7-ckt10 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: Andrei Otcheretianski <andrei.otcheretianski at intel.com>

commit 0f611d28fc2e13cfec64e1c544c16a086886805a upstream.

Since moving the interface combination checks to mac80211, it's
broken because it now only considers interfaces with an assigned
channel context, so for example any interface that isn't active
can still be up, which is clearly an issue; also, in particular
P2P-Device wdevs are an issue since they never have a chanctx.

Fix this by counting running interfaces instead the ones with a
channel context assigned.

Fixes: 73de86a38962b ("cfg80211/mac80211: move interface counting for combination check to mac80211")
Signed-off-by: Andrei Otcheretianski <andrei.otcheretianski at intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach at intel.com>
[rewrite commit message, dig out the commit it fixes]
Signed-off-by: Johannes Berg <johannes.berg at intel.com>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 net/mac80211/util.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/mac80211/util.c b/net/mac80211/util.c
index a6cda52ed920..01fe82e9d1b0 100644
--- a/net/mac80211/util.c
+++ b/net/mac80211/util.c
@@ -2896,7 +2896,7 @@ int ieee80211_check_combinations(struct ieee80211_sub_if_data *sdata,
 		wdev_iter = &sdata_iter->wdev;
 
 		if (sdata_iter == sdata ||
-		    rcu_access_pointer(sdata_iter->vif.chanctx_conf) == NULL ||
+		    !ieee80211_sdata_running(sdata_iter) ||
 		    local->hw.wiphy->software_iftypes & BIT(wdev_iter->iftype))
 			continue;