mac80211: use channel context notifications

Channel context pointer will be accessible on
both assign and unassign events.

Signed-off-by: Michal Kazior <michal.kazior@tieto.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

net/mac80211/chan.c

@@ -5,6 +5,7 @@
 #include <linux/nl80211.h>
 #include <net/cfg80211.h>
 #include "ieee80211_i.h"
+#include "driver-ops.h"
 
 static enum ieee80211_chan_mode
 __ieee80211_get_channel_mode(struct ieee80211_local *local,
@@ -205,6 +206,7 @@ ieee80211_new_chanctx(struct ieee80211_local *local,
 		      enum ieee80211_chanctx_mode mode)
 {
 	struct ieee80211_chanctx *ctx;
+	int err;
 
 	lockdep_assert_held(&local->chanctx_mtx);
 
@@ -216,6 +218,12 @@ ieee80211_new_chanctx(struct ieee80211_local *local,
 	ctx->conf.channel_type = channel_type;
 	ctx->mode = mode;
 
+	err = drv_add_chanctx(local, ctx);
+	if (err) {
+		kfree(ctx);
+		return ERR_PTR(err);
+	}
+
 	list_add(&ctx->list, &local->chanctx_list);
 
 	return ctx;
@@ -228,6 +236,8 @@ static void ieee80211_free_chanctx(struct ieee80211_local *local,
 
 	WARN_ON_ONCE(ctx->refcount != 0);
 
+	drv_remove_chanctx(local, ctx);
+
 	list_del(&ctx->list);
 	kfree_rcu(ctx, rcu_head);
 }
@@ -235,10 +245,15 @@ static void ieee80211_free_chanctx(struct ieee80211_local *local,
 static int ieee80211_assign_vif_chanctx(struct ieee80211_sub_if_data *sdata,
 					struct ieee80211_chanctx *ctx)
 {
-	struct ieee80211_local *local __maybe_unused = sdata->local;
+	struct ieee80211_local *local = sdata->local;
+	int ret;
 
 	lockdep_assert_held(&local->chanctx_mtx);
 
+	ret = drv_assign_vif_chanctx(local, sdata, ctx);
+	if (ret)
+		return ret;
+
 	rcu_assign_pointer(sdata->vif.chanctx_conf, &ctx->conf);
 	ctx->refcount++;
 
@@ -248,12 +263,14 @@ static int ieee80211_assign_vif_chanctx(struct ieee80211_sub_if_data *sdata,
 static void ieee80211_unassign_vif_chanctx(struct ieee80211_sub_if_data *sdata,
 					   struct ieee80211_chanctx *ctx)
 {
-	struct ieee80211_local *local __maybe_unused = sdata->local;
+	struct ieee80211_local *local = sdata->local;
 
 	lockdep_assert_held(&local->chanctx_mtx);
 
 	ctx->refcount--;
 	rcu_assign_pointer(sdata->vif.chanctx_conf, NULL);
+
+	drv_unassign_vif_chanctx(local, sdata, ctx);
 }
 
 static void __ieee80211_vif_release_channel(struct ieee80211_sub_if_data *sdata)