mac80211: fix time-is-after bug in mlme

commit 7d73cd946d4bc7d44cdc5121b1c61d5d71425dea upstream.

The incorrect timeout check caused probing to happen when it did
not need to happen.  This in turn caused tx performance drop
for around 5 seconds in ath10k-ct driver.  Possibly that tx drop
is due to a secondary issue, but fixing the probe to not happen
when traffic is running fixes the symptom.

Signed-off-by: Ben Greear <greearb@candelatech.com>
Fixes: 9abf4e49830d ("mac80211: optimize station connection monitor")
Acked-by: Felix Fietkau <nbd@nbd.name>
Link: https://lore.kernel.org/r/20210330230749.14097-1-greearb@candelatech.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c
index 3f483e8..ef19c33 100644 (file)
--- a/net/mac80211/mlme.c
+++ b/net/mac80211/mlme.c
@@ -4660,7 +4660,10 @@ static void ieee80211_sta_conn_mon_timer(struct timer_list *t)
                timeout = sta->rx_stats.last_rx;
        timeout += IEEE80211_CONNECTION_IDLE_TIME;
 
-       if (time_is_before_jiffies(timeout)) {
+       /* If timeout is after now, then update timer to fire at
+        * the later date, but do not actually probe at this time.
+        */
+       if (time_is_after_jiffies(timeout)) {
                mod_timer(&ifmgd->conn_mon_timer, round_jiffies_up(timeout));
                return;
        }