mac80211: check add_chanctx callback before use in ieee80211_reconfig

During testing our mac80211 driver a fatal error occurred which was
signalled to mac80211. Upon performing the reconfiguration of the
device a WARN_ON was triggered. This warning checked the return value
of drv_add_chanctx(). However, this returns -EOPNOTSUPP when the
driver does not provide the callback. As the callback is optional
better check it is defined before calling drv_add_chanctx().

Signed-off-by: Arend van Spriel <arend@broadcom.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

1 files changed, 6 insertions, 4 deletions

diff --git a/net/mac80211/util.c b/net/mac80211/util.c
index 5bad758abfb3..7fb55bf6561e 100644
--- a/net/mac80211/util.c
+++ b/net/mac80211/util.c
@@ -1417,10 +1417,12 @@ int ieee80211_reconfig(struct ieee80211_local *local)
         }
 
         /* add channel contexts */
-        mutex_lock(&local->chanctx_mtx);
-        list_for_each_entry(ctx, &local->chanctx_list, list)
-                WARN_ON(drv_add_chanctx(local, ctx));
-        mutex_unlock(&local->chanctx_mtx);
+        if (local->use_chanctx) {
+                mutex_lock(&local->chanctx_mtx);
+                list_for_each_entry(ctx, &local->chanctx_list, list)
+                        WARN_ON(drv_add_chanctx(local, ctx));
+                mutex_unlock(&local->chanctx_mtx);
+        }
 
         list_for_each_entry(sdata, &local->interfaces, list) {
                 struct ieee80211_chanctx_conf *ctx_conf;