wifi: mac80211: remove link before AP

If the AP removal timer is long, we don't really want to
remove the link immediately. However, we really should do
it _before_ the AP removes it (which happens at or after
count reaches 0), so subtract 1 from the countdown when
scheduling the timer. This causes the link removal work
to run just after the beacon with value 1 is received. If
the counter is already zero, do it immediately.

This fixes an issue where we do the removal too late and
receive a beacon from the AP that's no longer associated
with the MLD, but thus removed EHT and ML elements, and
then we disconnect instead from the whole MLD, since one
of the associated APs changed mode from EHT to HE.

Fixes: 8eb8dd2ffbbb ("wifi: mac80211: Support link removal using Reconfiguration ML element")
Reviewed-by: Ilan Peer <ilan.peer@intel.com>
Reviewed-by: Miriam Rachel Korenblit <miriam.rachel.korenblit@intel.com>
Link: https://msgid.link/20240418105220.03ac4a09fa74.Ifb8c8d38e3402721a81ce5981568f47b5c5889cb@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c
index 502c34d52fbec78b1617aba6a1a086aabda0ed63..6f0880ec89da047fb8517c7c1aae0849621ab448 100644 (file)
--- a/net/mac80211/mlme.c
+++ b/net/mac80211/mlme.c
@@ -5844,8 +5844,11 @@ static void ieee80211_ml_reconfiguration(struct ieee80211_sub_if_data *sdata,
                        continue;
                }
 
-               link_delay = link_conf->beacon_int *
-                       link_removal_timeout[link_id];
+               if (link_removal_timeout[link_id] < 1)
+                       link_delay = 0;
+               else
+                       link_delay = link_conf->beacon_int *
+                               (link_removal_timeout[link_id] - 1);
 
                if (!delay)
                        delay = link_delay;