From: Johannes Berg <johannes.berg@intel.com>
Date: Wed, 6 Jul 2022 08:09:57 +0000 (+0200)
Subject: wifi: mac80211: tighten locking check
X-Git-Tag: v6.6.17~6916^2~64^2~105
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=939c4c7e823b161701637720016999ef1f4ae4db;p=platform%2Fkernel%2Flinux-rpi.git

wifi: mac80211: tighten locking check

When we remove a link that doesn't have a channel context,
we don't really need the local->mtx locking. Tighten the
check here.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
---

diff --git a/net/mac80211/chan.c b/net/mac80211/chan.c
index 92fe405..5ab2107 100644
--- a/net/mac80211/chan.c
+++ b/net/mac80211/chan.c
@@ -1991,10 +1991,11 @@ void ieee80211_link_release_channel(struct ieee80211_link_data *link)
 
 	WARN_ON(sdata->dev && netif_carrier_ok(sdata->dev));
 
-	lockdep_assert_held(&sdata->local->mtx);
-
 	mutex_lock(&sdata->local->chanctx_mtx);
-	__ieee80211_link_release_channel(link);
+	if (rcu_access_pointer(link->conf->chanctx_conf)) {
+		lockdep_assert_held(&sdata->local->mtx);
+		__ieee80211_link_release_channel(link);
+	}
 	mutex_unlock(&sdata->local->chanctx_mtx);
 }