wifi: mac80211: correctly check if CSA is active

[ Upstream commit db1d0b6 ]

We are not adding an interface if an existing one is doing CSA.
But the check won't work for MLO station interfaces, since for those,
vif->bss_conf is zeroed out.
Fix this by checking if any link of the vif has an active CSA.

Reviewed-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Miri Korenblit <miriam.rachel.korenblit@intel.com>
Link: https://patch.msgid.link/20260111191912.7ceff62fc561.Ia38d27f42684d1cfd82d930d232bd5dea6ab9282@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

Author: Miriam-Rachel

net/mac80211/iface.c

@@ -350,6 +350,8 @@ static int ieee80211_check_concurrent_iface(struct ieee80211_sub_if_data *sdata,
 	/* we hold the RTNL here so can safely walk the list */
 	list_for_each_entry(nsdata, &local->interfaces, list) {
 		if (nsdata != sdata && ieee80211_sdata_running(nsdata)) {
+			struct ieee80211_link_data *link;
+
 			/*
 			 * Only OCB and monitor mode may coexist
 			 */
@@ -376,8 +378,10 @@ static int ieee80211_check_concurrent_iface(struct ieee80211_sub_if_data *sdata,
 			 * will not add another interface while any channel
 			 * switch is active.
 			 */
-			if (nsdata->vif.bss_conf.csa_active)
-				return -EBUSY;
+			for_each_link_data(nsdata, link) {
+				if (link->conf->csa_active)
+					return -EBUSY;
+			}
 
 			/*
 			 * The remaining checks are only performed for interfaces