wifi: mac80211: add ieee80211_vif_link_active() helper

We sometimes need to check if a link is active, and this
is complicated by the fact that active_links has no bits
set when the vif isn't (acting as) an MLD. Add a small
new helper ieee80211_vif_link_active() to make that a bit
easier, and use it in a few places.

Reviewed-by: Ilan Peer <ilan.peer@intel.com>
Reviewed-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Reviewed-by: Miriam Rachel Korenblit <miriam.rachel.korenblit@intel.com>
Link: https://msgid.link/20240228094901.688760aff5f7.I06892a503f5ecb9563fbd678d35d08daf7a044b0@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

include/net/mac80211.h

@@ -2011,6 +2011,21 @@ static inline bool ieee80211_vif_is_mld(const struct ieee80211_vif *vif)
 	return vif->valid_links != 0;
 }
 
+/**
+ * ieee80211_vif_link_active - check if a given link is active
+ * @vif: the vif
+ * @link_id: the link ID to check
+ * Return: %true if the vif is an MLD and the link is active, or if
+ *	the vif is not an MLD and the link ID is 0; %false otherwise.
+ */
+static inline bool ieee80211_vif_link_active(const struct ieee80211_vif *vif,
+					     unsigned int link_id)
+{
+	if (!ieee80211_vif_is_mld(vif))
+		return link_id == 0;
+	return vif->active_links & BIT(link_id);
+}
+
 #define for_each_vif_active_link(vif, link, link_id)				\
 	for (link_id = 0; link_id < ARRAY_SIZE((vif)->link_conf); link_id++)	\
 		if ((!(vif)->active_links ||					\

net/mac80211/cfg.c

@@ -3189,8 +3189,7 @@ int __ieee80211_request_smps_mgd(struct ieee80211_sub_if_data *sdata,
 	if (WARN_ON_ONCE(sdata->vif.type != NL80211_IFTYPE_STATION))
 		return -EINVAL;
 
-	if (ieee80211_vif_is_mld(&sdata->vif) &&
-	    !(sdata->vif.active_links & BIT(link->link_id)))
+	if (!ieee80211_vif_link_active(&sdata->vif, link->link_id))
 		return 0;
 
 	old_req = link->u.mgd.req_smps;

net/mac80211/chan.c

@@ -1701,8 +1701,7 @@ int ieee80211_link_use_channel(struct ieee80211_link_data *link,
 
 	lockdep_assert_wiphy(local->hw.wiphy);
 
-	if (sdata->vif.active_links &&
-	    !(sdata->vif.active_links & BIT(link->link_id))) {
+	if (!ieee80211_vif_link_active(&sdata->vif, link->link_id)) {
 		ieee80211_link_update_chanreq(link, chanreq);
 		return 0;
 	}

net/mac80211/driver-ops.c

@@ -1,7 +1,7 @@
 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * Copyright 2015 Intel Deutschland GmbH
- * Copyright (C) 2022-2023 Intel Corporation
+ * Copyright (C) 2022-2024 Intel Corporation
  */
 #include <net/mac80211.h>
 #include "ieee80211_i.h"
@@ -214,8 +214,7 @@ int drv_conf_tx(struct ieee80211_local *local,
 	if (!check_sdata_in_driver(sdata))
 		return -EIO;
 
-	if (sdata->vif.active_links &&
-	    !(sdata->vif.active_links & BIT(link->link_id)))
+	if (!ieee80211_vif_link_active(&sdata->vif, link->link_id))
 		return 0;
 
 	if (params->cw_min == 0 || params->cw_min > params->cw_max) {
@@ -315,8 +314,7 @@ int drv_assign_vif_chanctx(struct ieee80211_local *local,
 	if (!check_sdata_in_driver(sdata))
 		return -EIO;
 
-	if (sdata->vif.active_links &&
-	    !(sdata->vif.active_links & BIT(link_conf->link_id)))
+	if (!ieee80211_vif_link_active(&sdata->vif, link_conf->link_id))
 		return 0;
 
 	trace_drv_assign_vif_chanctx(local, sdata, link_conf, ctx);
@@ -343,8 +341,7 @@ void drv_unassign_vif_chanctx(struct ieee80211_local *local,
 	if (!check_sdata_in_driver(sdata))
 		return;
 
-	if (sdata->vif.active_links &&
-	    !(sdata->vif.active_links & BIT(link_conf->link_id)))
+	if (!ieee80211_vif_link_active(&sdata->vif, link_conf->link_id))
 		return;
 
 	trace_drv_unassign_vif_chanctx(local, sdata, link_conf, ctx);
@@ -461,8 +458,7 @@ void drv_link_info_changed(struct ieee80211_local *local,
 	if (!check_sdata_in_driver(sdata))
 		return;
 
-	if (sdata->vif.active_links &&
-	    !(sdata->vif.active_links & BIT(link_id)))
+	if (!ieee80211_vif_link_active(&sdata->vif, link_id))
 		return;
 
 	trace_drv_link_info_changed(local, sdata, info, changed);

net/mac80211/util.c

@@ -1935,8 +1935,7 @@ int ieee80211_reconfig(struct ieee80211_local *local)
 		for (link_id = 0;
 		     link_id < ARRAY_SIZE(sdata->vif.link_conf);
 		     link_id++) {
-			if (ieee80211_vif_is_mld(&sdata->vif) &&
-			    !(sdata->vif.active_links & BIT(link_id)))
+			if (!ieee80211_vif_link_active(&sdata->vif, link_id))
 				continue;
 
 			link = sdata_dereference(sdata->link[link_id], sdata);