wifi: cfg80211: Add link_id to cfg80211_ch_switch_started_notify()

Add link_id parameter to cfg80211_ch_switch_started_notify() to allow
driver to indicate on which link channel switch started on MLD.

Send the data to userspace so it knows as well.
Signed-off-by: Veerendranath Jakkam <quic_vjakkam@quicinc.com>
Link: https://lore.kernel.org/r/20220722131143.3438042-1-quic_vjakkam@quicinc.com
Link: https://lore.kernel.org/r/20220722131143.3438042-2-quic_vjakkam@quicinc.com
[squash two patches]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

include/net/cfg80211.h

@@ -8281,6 +8281,7 @@ void cfg80211_ch_switch_notify(struct net_device *dev,
  * cfg80211_ch_switch_started_notify - notify channel switch start
  * @dev: the device on which the channel switch started
  * @chandef: the future channel definition
+ * @link_id: the link ID for MLO, must be 0 for non-MLO
  * @count: the number of TBTTs until the channel switch happens
  * @quiet: whether or not immediate quiet was requested by the AP
  *
@@ -8290,7 +8291,8 @@ void cfg80211_ch_switch_notify(struct net_device *dev,
  */
 void cfg80211_ch_switch_started_notify(struct net_device *dev,
 				       struct cfg80211_chan_def *chandef,
-				       u8 count, bool quiet);
+				       unsigned int link_id, u8 count,
+				       bool quiet);
 
 /**
  * ieee80211_operating_class_to_band - convert operating class to band

net/mac80211/cfg.c

@@ -3815,7 +3815,7 @@ __ieee80211_channel_switch(struct wiphy *wiphy, struct net_device *dev,
 					  IEEE80211_QUEUE_STOP_REASON_CSA);
 
 	cfg80211_ch_switch_started_notify(sdata->dev,
-					  &sdata->deflink.csa_chandef,
+					  &sdata->deflink.csa_chandef, 0,
 					  params->count, params->block_tx);
 
 	if (changed) {

net/mac80211/mlme.c

@@ -1911,7 +1911,7 @@ ieee80211_sta_process_chanswitch(struct ieee80211_link_data *link,
 					  IEEE80211_QUEUE_STOP_REASON_CSA);
 	mutex_unlock(&local->mtx);
 
-	cfg80211_ch_switch_started_notify(sdata->dev, &csa_ie.chandef,
+	cfg80211_ch_switch_started_notify(sdata->dev, &csa_ie.chandef, 0,
 					  csa_ie.count, csa_ie.mode);
 
 	if (local->ops->channel_switch) {

net/wireless/nl80211.c

@@ -18932,11 +18932,13 @@ EXPORT_SYMBOL(cfg80211_pmksa_candidate_notify);
 
 static void nl80211_ch_switch_notify(struct cfg80211_registered_device *rdev,
 				     struct net_device *netdev,
+				     unsigned int link_id,
 				     struct cfg80211_chan_def *chandef,
 				     gfp_t gfp,
 				     enum nl80211_commands notif,
 				     u8 count, bool quiet)
 {
+	struct wireless_dev *wdev = netdev->ieee80211_ptr;
 	struct sk_buff *msg;
 	void *hdr;
 
@@ -18953,6 +18955,10 @@ static void nl80211_ch_switch_notify(struct cfg80211_registered_device *rdev,
 	if (nla_put_u32(msg, NL80211_ATTR_IFINDEX, netdev->ifindex))
 		goto nla_put_failure;
 
+	if (wdev->valid_links &&
+	    nla_put_u8(msg, NL80211_ATTR_MLO_LINK_ID, link_id))
+		goto nla_put_failure;
+
 	if (nl80211_send_chandef(msg, chandef))
 		goto nla_put_failure;
 
@@ -19012,22 +19018,26 @@ void cfg80211_ch_switch_notify(struct net_device *dev,
 
 	cfg80211_sched_dfs_chan_update(rdev);
 
-	nl80211_ch_switch_notify(rdev, dev, chandef, GFP_KERNEL,
+	nl80211_ch_switch_notify(rdev, dev, link_id, chandef, GFP_KERNEL,
 				 NL80211_CMD_CH_SWITCH_NOTIFY, 0, false);
 }
 EXPORT_SYMBOL(cfg80211_ch_switch_notify);
 
 void cfg80211_ch_switch_started_notify(struct net_device *dev,
 				       struct cfg80211_chan_def *chandef,
-				       u8 count, bool quiet)
+				       unsigned int link_id, u8 count,
+				       bool quiet)
 {
 	struct wireless_dev *wdev = dev->ieee80211_ptr;
 	struct wiphy *wiphy = wdev->wiphy;
 	struct cfg80211_registered_device *rdev = wiphy_to_rdev(wiphy);
 
-	trace_cfg80211_ch_switch_started_notify(dev, chandef);
+	ASSERT_WDEV_LOCK(wdev);
+	WARN_INVALID_LINK_ID(wdev, link_id);
+
+	trace_cfg80211_ch_switch_started_notify(dev, chandef, link_id);
 
-	nl80211_ch_switch_notify(rdev, dev, chandef, GFP_KERNEL,
+	nl80211_ch_switch_notify(rdev, dev, link_id, chandef, GFP_KERNEL,
 				 NL80211_CMD_CH_SWITCH_STARTED_NOTIFY,
 				 count, quiet);
 }

net/wireless/trace.h

@@ -3263,18 +3263,21 @@ TRACE_EVENT(cfg80211_ch_switch_notify,
 
 TRACE_EVENT(cfg80211_ch_switch_started_notify,
 	TP_PROTO(struct net_device *netdev,
-		 struct cfg80211_chan_def *chandef),
-	TP_ARGS(netdev, chandef),
+		 struct cfg80211_chan_def *chandef,
+		 unsigned int link_id),
+	TP_ARGS(netdev, chandef, link_id),
 	TP_STRUCT__entry(
 		NETDEV_ENTRY
 		CHAN_DEF_ENTRY
+		__field(unsigned int, link_id)
 	),
 	TP_fast_assign(
 		NETDEV_ASSIGN;
 		CHAN_DEF_ASSIGN(chandef);
+		__entry->link_id = link_id;
 	),
-	TP_printk(NETDEV_PR_FMT ", " CHAN_DEF_PR_FMT,
-		  NETDEV_PR_ARG, CHAN_DEF_PR_ARG)
+	TP_printk(NETDEV_PR_FMT ", " CHAN_DEF_PR_FMT ", link:%d",
+		  NETDEV_PR_ARG, CHAN_DEF_PR_ARG, __entry->link_id)
 );
 
 TRACE_EVENT(cfg80211_radar_event,