wifi: iwlwifi: mld: avoid selecting bad links

Currently, we don't select a link that wasn't heared in the last 5
seconds.
But if the link started to suffer from missed beacons more recent than
that, we might select this link even we really shouldn't,
leading to a disconnection instead of a link switch.

Fix this by checking if a link was heared in the last MLO scan,
if not - don't include it in the link selection.
Since we do an MLO scan on missed beacons, we will not hear that link in
that scan, and won't select it.

Signed-off-by: Miri Korenblit <miriam.rachel.korenblit@intel.com>
Reviewed-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Link: https://patch.msgid.link/20250309073442.8f950497219e.I51306021fe9231a8184e89c23707be47d3c05241@changeid
[replace cast with ULL constant]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

3 files changed, 11 insertions, 8 deletions

diff --git a/drivers/net/wireless/intel/iwlwifi/mld/mlo.c b/drivers/net/wireless/intel/iwlwifi/mld/mlo.c
index 99ba4018fb24..a5b1d373922a 100644
--- a/drivers/net/wireless/intel/iwlwifi/mld/mlo.c
+++ b/drivers/net/wireless/intel/iwlwifi/mld/mlo.c
@@ -704,10 +704,9 @@ iwl_mld_set_link_sel_data(struct iwl_mld *mld,
 		if (WARN_ON_ONCE(!link_conf))
 			continue;
 
-		/* Ignore any BSS that was not seen in the last 5 seconds */
+		/* Ignore any BSS that was not seen in the last MLO scan */
 		if (ktime_before(link_conf->bss->ts_boottime,
-				 ktime_sub_ns(ktime_get_boottime_ns(),
-					      (u64)5 * NSEC_PER_SEC)))
+				 mld->scan.last_mlo_scan_time))
 			continue;
 
 		data[n_data].link_id = link_id;
@@ -819,8 +818,9 @@ static void _iwl_mld_select_links(struct iwl_mld *mld,
 	if (!mld_vif->authorized || hweight16(usable_links) <= 1)
 		return;
 
-	if (WARN(time_before(mld->scan.last_mlo_scan_jiffies,
-			     jiffies - IWL_MLD_SCAN_EXPIRE_TIME),
+	if (WARN(ktime_before(mld->scan.last_mlo_scan_time,
+			      ktime_sub_ns(ktime_get_boottime_ns(),
+					   5ULL * NSEC_PER_SEC)),
 		"Last MLO scan was too long ago, can't select links\n"))
 		return;
 
diff --git a/drivers/net/wireless/intel/iwlwifi/mld/scan.c b/drivers/net/wireless/intel/iwlwifi/mld/scan.c
index 5f4ede92028b..7ec04318ec2f 100644
--- a/drivers/net/wireless/intel/iwlwifi/mld/scan.c
+++ b/drivers/net/wireless/intel/iwlwifi/mld/scan.c
@@ -1794,6 +1794,9 @@ static void iwl_mld_int_mlo_scan_start(struct iwl_mld *mld,
 	ret = _iwl_mld_single_scan_start(mld, vif, req, &ies,
 					 IWL_MLD_SCAN_INT_MLO);
 
+	if (!ret)
+		mld->scan.last_mlo_scan_time = ktime_get_boottime_ns();
+
 	IWL_DEBUG_SCAN(mld, "Internal MLO scan: ret=%d\n", ret);
 }
 
@@ -1922,7 +1925,6 @@ void iwl_mld_handle_scan_complete_notif(struct iwl_mld *mld,
 		mld->scan.pass_all_sched_res = SCHED_SCAN_PASS_ALL_STATE_DISABLED;
 	} else if (mld->scan.uid_status[uid] == IWL_MLD_SCAN_INT_MLO) {
 		IWL_DEBUG_SCAN(mld, "Internal MLO scan completed\n");
-		mld->scan.last_mlo_scan_jiffies = jiffies;
 
 		/*
 		 * We limit link selection to internal MLO scans as otherwise
diff --git a/drivers/net/wireless/intel/iwlwifi/mld/scan.h b/drivers/net/wireless/intel/iwlwifi/mld/scan.h
index cb589e002319..3ae940d55065 100644
--- a/drivers/net/wireless/intel/iwlwifi/mld/scan.h
+++ b/drivers/net/wireless/intel/iwlwifi/mld/scan.h
@@ -108,7 +108,8 @@ enum iwl_mld_traffic_load {
  *	in jiffies.
  * @last_start_time_jiffies: stores the last start time in jiffies
  *	(interface up/reset/resume).
- * @last_mlo_scan_jiffies: end time of the last MLO scan in jiffies.
+ * @last_mlo_scan_time: start time of the last MLO scan in nanoseconds since
+ *	boot.
  */
 struct iwl_mld_scan {
 	/* Add here fields that need clean up on restart */
@@ -129,7 +130,7 @@ struct iwl_mld_scan {
 	void *cmd;
 	unsigned long last_6ghz_passive_jiffies;
 	unsigned long last_start_time_jiffies;
-	unsigned long last_mlo_scan_jiffies;
+	unsigned long last_mlo_scan_time;
 };
 
 #endif /* __iwl_mld_scan_h__ */