cfg80211: fix interface combinations check for ADHOC(IBSS)
partial of commit 8e8b41f9d8c8e63fc92f899ace8da91a490ac573 upstream.
As part of commit 463454b5dbd8 ("cfg80211: fix interface
combinations check"), this extra check was introduced:
if ((all_iftypes & used_iftypes) != used_iftypes)
goto cont;
However, most wireless NIC drivers did not advertise ADHOC in
wiphy.iface_combinations[i].limits[] and hence we'll get -EBUSY
when we bring up a ADHOC wlan with commands similar to:
# iwconfig wlan0 mode ad-hoc && ifconfig wlan0 up
In commit 8e8b41f9d8c8e ("cfg80211: enforce lack of interface
combinations"), the change below fixes the issue:
if (total == 1)
return 0;
But it also introduces other dependencies for stable. For example,
a full cherry pick of 8e8b41f9d8c8e would introduce additional
regressions unless we also start cherry picking driver specific
fixes like the following:
9b4760e ath5k: add possible wiphy interface combinations
1ae2fc2 mac80211_hwsim: advertise interface combinations
20c8e8d ath9k: add possible wiphy interface combinations
And the purpose of the 'if (total == 1)' is to cover the specific
use case (IBSS, adhoc) that was mentioned above. So we just pick
the specific part out from 8e8b41f9d8c8e here.
Doing so gives stable kernels a way to fix the change introduced
by 463454b5dbd8, without having to make cherry picks specific to
various NIC drivers.
Signed-off-by: Liang Li <liang.li@windriver.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/net/wireless/util.c b/net/wireless/util.c
index 63b37d3..d835377 100644
--- a/net/wireless/util.c
+++ b/net/wireless/util.c
@@ -974,6 +974,9 @@
}
mutex_unlock(&rdev->devlist_mtx);
+ if (total == 1)
+ return 0;
+
for (i = 0; i < rdev->wiphy.n_iface_combinations; i++) {
const struct ieee80211_iface_combination *c;
struct ieee80211_iface_limit *limits;