From: Johannes Berg <johannes.berg@intel.com>

The current link iteration macros for_each_sdata_link() and
for_each_sdata_link_rcu() are various nested for loops, but
because they iterate all sdata instances and then all links
inside, using 'break' inside the iteration doesn't actually
break out of the whole iteration.

Make it work by tracking whether or not the inner iteration
(over links) actually completed, if it broke out then given
list_for_each_entry() it still iterates all sdata instances
but won't go into them.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
---
 net/mac80211/ieee80211_i.h | 16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)

diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index 73fd86ec1bce..d8c7abf4bca5 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -1239,9 +1239,12 @@ struct ieee80211_sub_if_data *vif_to_sdata(struct ieee80211_vif *p)
 	for (struct ieee80211_sub_if_data *___sdata = NULL;		\
 	     !___sdata;							\
 	     ___sdata = (void *)~0 /* always stop */)			\
+	for (int ___link_id = ARRAY_SIZE(___sdata->link);		\
+	     ___link_id; ___link_id = 0 /* always stop */)		\
 	list_for_each_entry(___sdata, &(_local)->interfaces, list)	\
-	if (ieee80211_sdata_running(___sdata))				\
-	for (int ___link_id = 0;					\
+	if (___link_id == ARRAY_SIZE(___sdata->link) &&			\
+	    ieee80211_sdata_running(___sdata))				\
+	for (___link_id = 0;						\
 	     ___link_id < ARRAY_SIZE(___sdata->link);			\
 	     ___link_id++)						\
 	if ((_link = wiphy_dereference((_local)->hw.wiphy,		\
@@ -1255,9 +1258,12 @@ struct ieee80211_sub_if_data *vif_to_sdata(struct ieee80211_vif *p)
 	for (struct ieee80211_sub_if_data *___sdata = NULL;				\
 	     !___sdata;									\
 	     ___sdata = (void *)~0 /* always stop */)					\
-	list_for_each_entry_rcu(___sdata, &(_local)->interfaces, list)			\
-	if (ieee80211_sdata_running(___sdata))						\
-	for (int ___link_id = 0;							\
+	for (int ___link_id = ARRAY_SIZE(___sdata->link);		\
+	     ___link_id; ___link_id = 0 /* always stop */)		\
+	list_for_each_entry(___sdata, &(_local)->interfaces, list)	\
+	if (___link_id == ARRAY_SIZE(___sdata->link) &&			\
+	    ieee80211_sdata_running(___sdata))				\
+	for (___link_id = 0;						\
 	     ___link_id < ARRAY_SIZE((___sdata)->link);					\
 	     ___link_id++)								\
 	if ((_link = rcu_dereference((___sdata)->link[___link_id])))
-- 
2.51.1

From: Johannes Berg <johannes.berg@intel.com>

Each link can currently use a chanctx and have another one
reserved, and both of these are also tracked backwards in
the assigned_links and reserved_links lists. If we consider
that there aren't *that* many links, this duplicate book-
keeping isn't necessary.
(I think it used to be necessary before the wiphy locking
changes, when chanctx_mtx existed, because we couldn't do
any interface iterations while holding only chanctx_mtx.)

Additionally, for NAN, we're going to want to track which
chanctxs are in use by the (group of) NAN interfaces. For
those, links don't really make sense as such, so chanctxs
need to be assigned to a different data structure.

Thus, as a first step, remove those back-lists of users
(right now only links) of each channel context. This is a
very basic conversion, ieee80211_vif_use_reserved_switch()
should made to iterate smarter.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
---
 net/mac80211/chan.c        | 127 +++++++++++++++++++++----------------
 net/mac80211/ieee80211_i.h |   6 --
 net/mac80211/link.c        |   2 -
 net/mac80211/util.c        |  32 +++++-----
 4 files changed, 88 insertions(+), 79 deletions(-)

diff --git a/net/mac80211/chan.c b/net/mac80211/chan.c
index 57065714cf8c..b73b5a0f6e60 100644
--- a/net/mac80211/chan.c
+++ b/net/mac80211/chan.c
@@ -20,8 +20,10 @@ static int ieee80211_chanctx_num_assigned(struct ieee80211_local *local,
 
 	lockdep_assert_wiphy(local->hw.wiphy);
 
-	list_for_each_entry(link, &ctx->assigned_links, assigned_chanctx_list)
-		num++;
+	for_each_sdata_link(local, link) {
+		if (rcu_access_pointer(link->conf->chanctx_conf) == &ctx->conf)
+			num++;
+	}
 
 	return num;
 }
@@ -34,8 +36,10 @@ static int ieee80211_chanctx_num_reserved(struct ieee80211_local *local,
 
 	lockdep_assert_wiphy(local->hw.wiphy);
 
-	list_for_each_entry(link, &ctx->reserved_links, reserved_chanctx_list)
-		num++;
+	for_each_sdata_link(local, link) {
+		if (link->reserved_chanctx == ctx)
+			num++;
+	}
 
 	return num;
 }
@@ -43,8 +47,19 @@ static int ieee80211_chanctx_num_reserved(struct ieee80211_local *local,
 int ieee80211_chanctx_refcount(struct ieee80211_local *local,
 			       struct ieee80211_chanctx *ctx)
 {
-	return ieee80211_chanctx_num_assigned(local, ctx) +
-	       ieee80211_chanctx_num_reserved(local, ctx);
+	struct ieee80211_link_data *link;
+	int num = 0;
+
+	lockdep_assert_wiphy(local->hw.wiphy);
+
+	for_each_sdata_link(local, link) {
+		if (rcu_access_pointer(link->conf->chanctx_conf) == &ctx->conf)
+			num++;
+		if (link->reserved_chanctx == ctx)
+			num++;
+	}
+
+	return num;
 }
 
 static int ieee80211_num_chanctx(struct ieee80211_local *local, int radio_idx)
@@ -150,7 +165,10 @@ ieee80211_chanctx_reserved_chanreq(struct ieee80211_local *local,
 	if (WARN_ON(!req))
 		return NULL;
 
-	list_for_each_entry(link, &ctx->reserved_links, reserved_chanctx_list) {
+	for_each_sdata_link(local, link) {
+		if (link->reserved_chanctx != ctx)
+			continue;
+
 		req = ieee80211_chanreq_compatible(&link->reserved, req, tmp);
 		if (!req)
 			break;
@@ -170,9 +188,12 @@ ieee80211_chanctx_non_reserved_chandef(struct ieee80211_local *local,
 
 	lockdep_assert_wiphy(local->hw.wiphy);
 
-	list_for_each_entry(link, &ctx->assigned_links, assigned_chanctx_list) {
+	for_each_sdata_link(local, link) {
 		struct ieee80211_bss_conf *link_conf = link->conf;
 
+		if (rcu_access_pointer(link_conf->chanctx_conf) != &ctx->conf)
+			continue;
+
 		if (link->reserved_chanctx)
 			continue;
 
@@ -200,7 +221,7 @@ ieee80211_chanctx_can_reserve(struct ieee80211_local *local,
 	if (!ieee80211_chanctx_non_reserved_chandef(local, ctx, req, &tmp))
 		return false;
 
-	if (!list_empty(&ctx->reserved_links) &&
+	if (ieee80211_chanctx_num_reserved(local, ctx) != 0 &&
 	    ieee80211_chanctx_reserved_chanreq(local, ctx, req, &tmp))
 		return true;
 
@@ -633,8 +654,6 @@ ieee80211_find_chanctx(struct ieee80211_local *local,
 		 * context to actually be removed.
 		 */
 		link->reserved_chanctx = ctx;
-		list_add(&link->reserved_chanctx_list,
-			 &ctx->reserved_links);
 
 		ieee80211_change_chanctx(local, ctx, ctx, compat);
 
@@ -705,8 +724,6 @@ ieee80211_alloc_chanctx(struct ieee80211_local *local,
 	if (!ctx)
 		return NULL;
 
-	INIT_LIST_HEAD(&ctx->assigned_links);
-	INIT_LIST_HEAD(&ctx->reserved_links);
 	ctx->conf.def = chanreq->oper;
 	ctx->conf.ap = chanreq->ap;
 	ctx->conf.rx_chains_static = 1;
@@ -904,7 +921,6 @@ static int ieee80211_assign_link_chanctx(struct ieee80211_link_data *link,
 
 		drv_unassign_vif_chanctx(local, sdata, link->conf, curr_ctx);
 		conf = NULL;
-		list_del(&link->assigned_chanctx_list);
 	}
 
 	if (new_ctx) {
@@ -919,9 +935,6 @@ static int ieee80211_assign_link_chanctx(struct ieee80211_link_data *link,
 
 			/* succeeded, so commit it to the data structures */
 			conf = &new_ctx->conf;
-			if (!local->in_reconfig)
-				list_add(&link->assigned_chanctx_list,
-					 &new_ctx->assigned_links);
 		}
 	} else {
 		ret = 0;
@@ -1108,7 +1121,6 @@ void ieee80211_link_unreserve_chanctx(struct ieee80211_link_data *link)
 	if (WARN_ON(!ctx))
 		return;
 
-	list_del(&link->reserved_chanctx_list);
 	link->reserved_chanctx = NULL;
 
 	if (ieee80211_chanctx_refcount(sdata->local, ctx) == 0) {
@@ -1142,9 +1154,9 @@ ieee80211_replace_chanctx(struct ieee80211_local *local,
 	struct wiphy *wiphy = local->hw.wiphy;
 	const struct wiphy_radio *radio;
 
-	if (!curr_ctx || (curr_ctx->replace_state ==
-			  IEEE80211_CHANCTX_WILL_BE_REPLACED) ||
-	    !list_empty(&curr_ctx->reserved_links)) {
+	if (!curr_ctx ||
+	    curr_ctx->replace_state == IEEE80211_CHANCTX_WILL_BE_REPLACED ||
+	    ieee80211_chanctx_num_reserved(local, curr_ctx) != 0) {
 		/*
 		 * Another link already requested this context for a
 		 * reservation. Find another one hoping all links assigned
@@ -1167,7 +1179,7 @@ ieee80211_replace_chanctx(struct ieee80211_local *local,
 			    IEEE80211_CHANCTX_REPLACE_NONE)
 				continue;
 
-			if (!list_empty(&ctx->reserved_links))
+			if (ieee80211_chanctx_num_reserved(local, ctx) != 0)
 				continue;
 
 			if (ctx->conf.radio_idx >= 0) {
@@ -1185,9 +1197,9 @@ ieee80211_replace_chanctx(struct ieee80211_local *local,
 	 * If that's true then all available contexts already have reservations
 	 * and cannot be used.
 	 */
-	if (!curr_ctx || (curr_ctx->replace_state ==
-			  IEEE80211_CHANCTX_WILL_BE_REPLACED) ||
-	    !list_empty(&curr_ctx->reserved_links))
+	if (!curr_ctx ||
+	    curr_ctx->replace_state == IEEE80211_CHANCTX_WILL_BE_REPLACED ||
+	    ieee80211_chanctx_num_reserved(local, curr_ctx) != 0)
 		return ERR_PTR(-EBUSY);
 
 	new_ctx = ieee80211_alloc_chanctx(local, chanreq, mode, -1);
@@ -1267,7 +1279,6 @@ int ieee80211_link_reserve_chanctx(struct ieee80211_link_data *link,
 			return PTR_ERR(new_ctx);
 	}
 
-	list_add(&link->reserved_chanctx_list, &new_ctx->reserved_links);
 	link->reserved_chanctx = new_ctx;
 	link->reserved = *chanreq;
 	link->reserved_radar_required = radar_required;
@@ -1381,7 +1392,6 @@ ieee80211_link_use_reserved_reassign(struct ieee80211_link_data *link)
 	vif_chsw[0].new_ctx = &new_ctx->conf;
 	vif_chsw[0].link_conf = link->conf;
 
-	list_del(&link->reserved_chanctx_list);
 	link->reserved_chanctx = NULL;
 
 	err = drv_switch_vif_chanctx(local, vif_chsw, 1,
@@ -1394,7 +1404,6 @@ ieee80211_link_use_reserved_reassign(struct ieee80211_link_data *link)
 	}
 
 	link->radar_required = link->reserved_radar_required;
-	list_move(&link->assigned_chanctx_list, &new_ctx->assigned_links);
 	rcu_assign_pointer(link_conf->chanctx_conf, &new_ctx->conf);
 
 	if (sdata->vif.type == NL80211_IFTYPE_AP)
@@ -1451,7 +1460,6 @@ ieee80211_link_use_reserved_assign(struct ieee80211_link_data *link)
 
 	ieee80211_change_chanctx(local, new_ctx, new_ctx, chanreq);
 
-	list_del(&link->reserved_chanctx_list);
 	link->reserved_chanctx = NULL;
 
 	err = ieee80211_assign_link_chanctx(link, new_ctx, false);
@@ -1517,8 +1525,10 @@ static int ieee80211_chsw_switch_vifs(struct ieee80211_local *local,
 			goto out;
 		}
 
-		list_for_each_entry(link, &ctx->reserved_links,
-				    reserved_chanctx_list) {
+		for_each_sdata_link(local, link) {
+			if (link->reserved_chanctx != ctx)
+				continue;
+
 			if (!ieee80211_link_has_in_place_reservation(link))
 				continue;
 
@@ -1551,7 +1561,7 @@ static int ieee80211_chsw_switch_ctxs(struct ieee80211_local *local)
 		if (ctx->replace_state != IEEE80211_CHANCTX_REPLACES_OTHER)
 			continue;
 
-		if (!list_empty(&ctx->replace_ctx->assigned_links))
+		if (ieee80211_chanctx_num_assigned(local, ctx) != 0)
 			continue;
 
 		ieee80211_del_chanctx(local, ctx->replace_ctx, false);
@@ -1568,7 +1578,7 @@ static int ieee80211_chsw_switch_ctxs(struct ieee80211_local *local)
 		if (ctx->replace_state != IEEE80211_CHANCTX_REPLACES_OTHER)
 			continue;
 
-		if (!list_empty(&ctx->replace_ctx->assigned_links))
+		if (ieee80211_chanctx_num_assigned(local, ctx) != 0)
 			continue;
 
 		ieee80211_del_chanctx(local, ctx, false);
@@ -1619,8 +1629,10 @@ static int ieee80211_vif_use_reserved_switch(struct ieee80211_local *local)
 		n_reserved = 0;
 		n_ready = 0;
 
-		list_for_each_entry(link, &ctx->replace_ctx->assigned_links,
-				    assigned_chanctx_list) {
+		for_each_sdata_link(local, link) {
+			if (rcu_access_pointer(link->conf->chanctx_conf) != &ctx->conf)
+				continue;
+
 			n_assigned++;
 			if (link->reserved_chanctx) {
 				n_reserved++;
@@ -1641,8 +1653,10 @@ static int ieee80211_vif_use_reserved_switch(struct ieee80211_local *local)
 		}
 
 		ctx->conf.radar_enabled = false;
-		list_for_each_entry(link, &ctx->reserved_links,
-				    reserved_chanctx_list) {
+		for_each_sdata_link(local, link) {
+			if (link->reserved_chanctx != ctx)
+				continue;
+
 			if (ieee80211_link_has_in_place_reservation(link) &&
 			    !link->reserved_ready)
 				return -EAGAIN;
@@ -1683,8 +1697,10 @@ static int ieee80211_vif_use_reserved_switch(struct ieee80211_local *local)
 			goto err;
 		}
 
-		list_for_each_entry(link, &ctx->reserved_links,
-				    reserved_chanctx_list) {
+		for_each_sdata_link(local, link) {
+			if (link->reserved_chanctx != ctx)
+				continue;
+
 			if (!ieee80211_link_has_in_place_reservation(link))
 				continue;
 
@@ -1718,7 +1734,7 @@ static int ieee80211_vif_use_reserved_switch(struct ieee80211_local *local)
 	 * context(s).
 	 */
 	list_for_each_entry(ctx, &local->chanctx_list, list) {
-		struct ieee80211_link_data *link, *link_tmp;
+		struct ieee80211_link_data *link;
 
 		if (ctx->replace_state != IEEE80211_CHANCTX_REPLACES_OTHER)
 			continue;
@@ -1728,12 +1744,14 @@ static int ieee80211_vif_use_reserved_switch(struct ieee80211_local *local)
 			goto err;
 		}
 
-		list_for_each_entry(link, &ctx->reserved_links,
-				    reserved_chanctx_list) {
+		for_each_sdata_link(local, link) {
 			struct ieee80211_sub_if_data *sdata = link->sdata;
 			struct ieee80211_bss_conf *link_conf = link->conf;
 			u64 changed = 0;
 
+			if (link->reserved_chanctx != ctx)
+				continue;
+
 			if (!ieee80211_link_has_in_place_reservation(link))
 				continue;
 
@@ -1765,14 +1783,13 @@ static int ieee80211_vif_use_reserved_switch(struct ieee80211_local *local)
 		ieee80211_recalc_radar_chanctx(local, ctx);
 		ieee80211_recalc_chanctx_min_def(local, ctx, NULL, false);
 
-		list_for_each_entry_safe(link, link_tmp, &ctx->reserved_links,
-					 reserved_chanctx_list) {
+		for_each_sdata_link(local, link) {
+			if (link->reserved_chanctx != ctx)
+				continue;
+
 			if (ieee80211_link_get_chanctx(link) != ctx)
 				continue;
 
-			list_del(&link->reserved_chanctx_list);
-			list_move(&link->assigned_chanctx_list,
-				  &ctx->assigned_links);
 			link->reserved_chanctx = NULL;
 
 			ieee80211_link_chanctx_reservation_complete(link);
@@ -1786,12 +1803,11 @@ static int ieee80211_vif_use_reserved_switch(struct ieee80211_local *local)
 		 * reservation for originally requested interface has already
 		 * succeeded at this point.
 		 */
-		list_for_each_entry_safe(link, link_tmp, &ctx->reserved_links,
-					 reserved_chanctx_list) {
-			if (WARN_ON(ieee80211_link_has_in_place_reservation(link)))
+		for_each_sdata_link(local, link) {
+			if (link->reserved_chanctx != ctx)
 				continue;
 
-			if (WARN_ON(link->reserved_chanctx != ctx))
+			if (WARN_ON(ieee80211_link_has_in_place_reservation(link)))
 				continue;
 
 			if (!link->reserved_ready)
@@ -1834,13 +1850,15 @@ static int ieee80211_vif_use_reserved_switch(struct ieee80211_local *local)
 
 err:
 	list_for_each_entry(ctx, &local->chanctx_list, list) {
-		struct ieee80211_link_data *link, *link_tmp;
+		struct ieee80211_link_data *link;
 
 		if (ctx->replace_state != IEEE80211_CHANCTX_REPLACES_OTHER)
 			continue;
 
-		list_for_each_entry_safe(link, link_tmp, &ctx->reserved_links,
-					 reserved_chanctx_list) {
+		for_each_sdata_link(local, link) {
+			if (link->reserved_chanctx != ctx)
+				continue;
+
 			ieee80211_link_unreserve_chanctx(link);
 			ieee80211_link_chanctx_reservation_complete(link);
 		}
@@ -1949,7 +1967,6 @@ int _ieee80211_link_use_channel(struct ieee80211_link_data *link,
 		/* remove reservation */
 		WARN_ON(link->reserved_chanctx != ctx);
 		link->reserved_chanctx = NULL;
-		list_del(&link->reserved_chanctx_list);
 	}
 
 	if (ret) {
diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index d8c7abf4bca5..3381e6d6cfd7 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -916,9 +916,6 @@ struct ieee80211_chanctx {
 	struct list_head list;
 	struct rcu_head rcu_head;
 
-	struct list_head assigned_links;
-	struct list_head reserved_links;
-
 	enum ieee80211_chanctx_replace_state replace_state;
 	struct ieee80211_chanctx *replace_ctx;
 
@@ -1071,9 +1068,6 @@ struct ieee80211_link_data {
 	struct ieee80211_sub_if_data *sdata;
 	unsigned int link_id;
 
-	struct list_head assigned_chanctx_list; /* protected by wiphy mutex */
-	struct list_head reserved_chanctx_list; /* protected by wiphy mutex */
-
 	/* multicast keys only */
 	struct ieee80211_key __rcu *gtk[NUM_DEFAULT_KEYS +
 					NUM_DEFAULT_MGMT_KEYS +
diff --git a/net/mac80211/link.c b/net/mac80211/link.c
index d71eabe5abf8..c05d9c6aa8f2 100644
--- a/net/mac80211/link.c
+++ b/net/mac80211/link.c
@@ -119,8 +119,6 @@ void ieee80211_link_init(struct ieee80211_sub_if_data *sdata,
 			ieee80211_color_change_finalize_work);
 	wiphy_delayed_work_init(&link->color_collision_detect_work,
 				ieee80211_color_collision_detection_work);
-	INIT_LIST_HEAD(&link->assigned_chanctx_list);
-	INIT_LIST_HEAD(&link->reserved_chanctx_list);
 	wiphy_delayed_work_init(&link->dfs_cac_timer_work,
 				ieee80211_dfs_cac_timer_work);
 
diff --git a/net/mac80211/util.c b/net/mac80211/util.c
index c9931537f9d2..324d84d11cab 100644
--- a/net/mac80211/util.c
+++ b/net/mac80211/util.c
@@ -4016,23 +4016,23 @@ static u8 ieee80211_chanctx_radar_detect(struct ieee80211_local *local,
 	if (WARN_ON(ctx->replace_state == IEEE80211_CHANCTX_WILL_BE_REPLACED))
 		return 0;
 
-	list_for_each_entry(link, &ctx->reserved_links, reserved_chanctx_list)
-		if (link->reserved_radar_required)
+	for_each_sdata_link(local, link) {
+		if (rcu_access_pointer(link->conf->chanctx_conf) == &ctx->conf) {
+			/*
+			 * An in-place reservation context should not have any
+			 * assigned links until it replaces the other context.
+			 */
+			WARN_ON(ctx->replace_state ==
+				IEEE80211_CHANCTX_REPLACES_OTHER);
+
+			if (link->radar_required)
+				radar_detect |=
+					BIT(link->conf->chanreq.oper.width);
+		}
+
+		if (link->reserved_chanctx == ctx &&
+		    link->reserved_radar_required)
 			radar_detect |= BIT(link->reserved.oper.width);
-
-	/*
-	 * An in-place reservation context should not have any assigned vifs
-	 * until it replaces the other context.
-	 */
-	WARN_ON(ctx->replace_state == IEEE80211_CHANCTX_REPLACES_OTHER &&
-		!list_empty(&ctx->assigned_links));
-
-	list_for_each_entry(link, &ctx->assigned_links, assigned_chanctx_list) {
-		if (!link->radar_required)
-			continue;
-
-		radar_detect |=
-			BIT(link->conf->chanreq.oper.width);
 	}
 
 	return radar_detect;
-- 
2.51.1

From: Johannes Berg <johannes.berg@intel.com>

ieee80211_recalc_chanctx_min_def() is used outside the chandef
code, but then should/is always used with NULL/false for the
two last arguments. Remove them, and create another level of
indirection for use inside the file.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
---
 net/mac80211/chan.c        | 46 ++++++++++++++++++++++----------------
 net/mac80211/he.c          |  6 ++---
 net/mac80211/ieee80211_i.h |  4 +---
 net/mac80211/util.c        |  2 +-
 4 files changed, 32 insertions(+), 26 deletions(-)

diff --git a/net/mac80211/chan.c b/net/mac80211/chan.c
index b73b5a0f6e60..e4f765d1e879 100644
--- a/net/mac80211/chan.c
+++ b/net/mac80211/chan.c
@@ -410,10 +410,10 @@ ieee80211_get_chanctx_max_required_bw(struct ieee80211_local *local,
  * channel context.
  */
 static u32
-_ieee80211_recalc_chanctx_min_def(struct ieee80211_local *local,
-				  struct ieee80211_chanctx *ctx,
-				  struct ieee80211_link_data *rsvd_for,
-				  bool check_reserved)
+__ieee80211_recalc_chanctx_min_def(struct ieee80211_local *local,
+				   struct ieee80211_chanctx *ctx,
+				   struct ieee80211_link_data *rsvd_for,
+				   bool check_reserved)
 {
 	enum nl80211_chan_width max_bw;
 	struct cfg80211_chan_def min_def;
@@ -518,13 +518,14 @@ static void ieee80211_chan_bw_change(struct ieee80211_local *local,
  * the max of min required widths of all the interfaces bound to this
  * channel context.
  */
-void ieee80211_recalc_chanctx_min_def(struct ieee80211_local *local,
-				      struct ieee80211_chanctx *ctx,
-				      struct ieee80211_link_data *rsvd_for,
-				      bool check_reserved)
+static void
+_ieee80211_recalc_chanctx_min_def(struct ieee80211_local *local,
+				  struct ieee80211_chanctx *ctx,
+				  struct ieee80211_link_data *rsvd_for,
+				  bool check_reserved)
 {
-	u32 changed = _ieee80211_recalc_chanctx_min_def(local, ctx, rsvd_for,
-							check_reserved);
+	u32 changed = __ieee80211_recalc_chanctx_min_def(local, ctx, rsvd_for,
+							 check_reserved);
 
 	if (!changed)
 		return;
@@ -538,6 +539,12 @@ void ieee80211_recalc_chanctx_min_def(struct ieee80211_local *local,
 	ieee80211_chan_bw_change(local, ctx, false, false);
 }
 
+void ieee80211_recalc_chanctx_min_def(struct ieee80211_local *local,
+				      struct ieee80211_chanctx *ctx)
+{
+	_ieee80211_recalc_chanctx_min_def(local, ctx, NULL, false);
+}
+
 static void _ieee80211_change_chanctx(struct ieee80211_local *local,
 				      struct ieee80211_chanctx *ctx,
 				      struct ieee80211_chanctx *old_ctx,
@@ -572,7 +579,7 @@ static void _ieee80211_change_chanctx(struct ieee80211_local *local,
 	ieee80211_chan_bw_change(local, old_ctx, false, true);
 
 	if (ieee80211_chanreq_identical(&ctx_req, chanreq)) {
-		ieee80211_recalc_chanctx_min_def(local, ctx, rsvd_for, false);
+		_ieee80211_recalc_chanctx_min_def(local, ctx, rsvd_for, false);
 		return;
 	}
 
@@ -593,7 +600,8 @@ static void _ieee80211_change_chanctx(struct ieee80211_local *local,
 	ctx->conf.ap = chanreq->ap;
 
 	/* check if min chanctx also changed */
-	changed |= _ieee80211_recalc_chanctx_min_def(local, ctx, rsvd_for, false);
+	changed |= __ieee80211_recalc_chanctx_min_def(local, ctx, rsvd_for,
+						      false);
 
 	ieee80211_add_wbrf(local, &ctx->conf.def);
 
@@ -732,7 +740,7 @@ ieee80211_alloc_chanctx(struct ieee80211_local *local,
 	ctx->conf.radar_enabled = false;
 	ctx->conf.radio_idx = radio_idx;
 	ctx->radar_detected = false;
-	_ieee80211_recalc_chanctx_min_def(local, ctx, NULL, false);
+	__ieee80211_recalc_chanctx_min_def(local, ctx, NULL, false);
 
 	return ctx;
 }
@@ -925,7 +933,7 @@ static int ieee80211_assign_link_chanctx(struct ieee80211_link_data *link,
 
 	if (new_ctx) {
 		/* recalc considering the link we'll use it for now */
-		ieee80211_recalc_chanctx_min_def(local, new_ctx, link, false);
+		_ieee80211_recalc_chanctx_min_def(local, new_ctx, link, false);
 
 		ret = drv_assign_vif_chanctx(local, sdata, link->conf, new_ctx);
 		if (assign_on_failure || !ret) {
@@ -946,12 +954,12 @@ static int ieee80211_assign_link_chanctx(struct ieee80211_link_data *link,
 		ieee80211_recalc_chanctx_chantype(local, curr_ctx);
 		ieee80211_recalc_smps_chanctx(local, curr_ctx);
 		ieee80211_recalc_radar_chanctx(local, curr_ctx);
-		ieee80211_recalc_chanctx_min_def(local, curr_ctx, NULL, false);
+		ieee80211_recalc_chanctx_min_def(local, curr_ctx);
 	}
 
 	if (new_ctx && ieee80211_chanctx_num_assigned(local, new_ctx) > 0) {
 		ieee80211_recalc_txpower(link, false);
-		ieee80211_recalc_chanctx_min_def(local, new_ctx, NULL, false);
+		ieee80211_recalc_chanctx_min_def(local, new_ctx);
 	}
 
 	if (conf) {
@@ -1414,7 +1422,7 @@ ieee80211_link_use_reserved_reassign(struct ieee80211_link_data *link)
 	if (ieee80211_chanctx_refcount(local, old_ctx) == 0)
 		ieee80211_free_chanctx(local, old_ctx, false);
 
-	ieee80211_recalc_chanctx_min_def(local, new_ctx, NULL, false);
+	ieee80211_recalc_chanctx_min_def(local, new_ctx);
 	ieee80211_recalc_smps_chanctx(local, new_ctx);
 	ieee80211_recalc_radar_chanctx(local, new_ctx);
 
@@ -1709,7 +1717,7 @@ static int ieee80211_vif_use_reserved_switch(struct ieee80211_local *local)
 						 true, true);
 		}
 
-		ieee80211_recalc_chanctx_min_def(local, ctx, NULL, true);
+		_ieee80211_recalc_chanctx_min_def(local, ctx, NULL, true);
 	}
 
 	/*
@@ -1781,7 +1789,7 @@ static int ieee80211_vif_use_reserved_switch(struct ieee80211_local *local)
 		ieee80211_recalc_chanctx_chantype(local, ctx);
 		ieee80211_recalc_smps_chanctx(local, ctx);
 		ieee80211_recalc_radar_chanctx(local, ctx);
-		ieee80211_recalc_chanctx_min_def(local, ctx, NULL, false);
+		ieee80211_recalc_chanctx_min_def(local, ctx);
 
 		for_each_sdata_link(local, link) {
 			if (link->reserved_chanctx != ctx)
diff --git a/net/mac80211/he.c b/net/mac80211/he.c
index 5792ef77e986..f7b05e59374c 100644
--- a/net/mac80211/he.c
+++ b/net/mac80211/he.c
@@ -3,7 +3,7 @@
  * HE handling
  *
  * Copyright(c) 2017 Intel Deutschland GmbH
- * Copyright(c) 2019 - 2024 Intel Corporation
+ * Copyright(c) 2019-2025 Intel Corporation
  */
 
 #include "ieee80211_i.h"
@@ -313,7 +313,7 @@ bool ieee80211_prepare_rx_omi_bw(struct ieee80211_link_sta *pub_link_sta,
 		ieee80211_link_sta_rc_update_omi(link, link_sta);
 	} else {
 		link_sta->rx_omi_bw_rx = bw;
-		ieee80211_recalc_chanctx_min_def(local, chanctx, NULL, false);
+		ieee80211_recalc_chanctx_min_def(local, chanctx);
 	}
 
 	link_sta->rx_omi_bw_staging = bw;
@@ -359,7 +359,7 @@ void ieee80211_finalize_rx_omi_bw(struct ieee80211_link_sta *pub_link_sta)
 		/* channel context in finalize only when narrowing bandwidth */
 		WARN_ON(link_sta->rx_omi_bw_rx < link_sta->rx_omi_bw_staging);
 		link_sta->rx_omi_bw_rx = link_sta->rx_omi_bw_staging;
-		ieee80211_recalc_chanctx_min_def(local, chanctx, NULL, false);
+		ieee80211_recalc_chanctx_min_def(local, chanctx);
 	}
 
 	trace_api_return_void(local);
diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index 3381e6d6cfd7..751ac32c2b55 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -2768,9 +2768,7 @@ int ieee80211_chanctx_refcount(struct ieee80211_local *local,
 void ieee80211_recalc_smps_chanctx(struct ieee80211_local *local,
 				   struct ieee80211_chanctx *chanctx);
 void ieee80211_recalc_chanctx_min_def(struct ieee80211_local *local,
-				      struct ieee80211_chanctx *ctx,
-				      struct ieee80211_link_data *rsvd_for,
-				      bool check_reserved);
+				      struct ieee80211_chanctx *ctx);
 bool ieee80211_is_radar_required(struct ieee80211_local *local,
 				 struct cfg80211_scan_request *req);
 bool ieee80211_is_radio_idx_in_scan_req(struct wiphy *wiphy,
diff --git a/net/mac80211/util.c b/net/mac80211/util.c
index 324d84d11cab..1a128f7aae82 100644
--- a/net/mac80211/util.c
+++ b/net/mac80211/util.c
@@ -2347,7 +2347,7 @@ void ieee80211_recalc_min_chandef(struct ieee80211_sub_if_data *sdata,
 
 		chanctx = container_of(chanctx_conf, struct ieee80211_chanctx,
 				       conf);
-		ieee80211_recalc_chanctx_min_def(local, chanctx, NULL, false);
+		ieee80211_recalc_chanctx_min_def(local, chanctx);
 	}
 }
 
-- 
2.51.1

From: Johannes Berg <johannes.berg@intel.com>

In preparation for NAN interfaces using multiple channel
contexts, add an iterator macro that iterates all users
of a given channel context.

The logic during reserved assign/reassign handling the
bandwidth in ieee80211_get_chanctx_max_required_bw() is
a bit more complicated and should be cleaned up, so it
isn't yet converted.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
---
 net/mac80211/chan.c | 342 +++++++++++++++++++++++++-------------------
 1 file changed, 195 insertions(+), 147 deletions(-)

diff --git a/net/mac80211/chan.c b/net/mac80211/chan.c
index e4f765d1e879..e3081e2fa772 100644
--- a/net/mac80211/chan.c
+++ b/net/mac80211/chan.c
@@ -12,18 +12,132 @@
 #include "driver-ops.h"
 #include "rate.h"
 
+struct ieee80211_chanctx_user_iter {
+	struct ieee80211_chan_req *chanreq;
+	struct ieee80211_sub_if_data *sdata;
+	struct ieee80211_link_data *link;
+	enum nl80211_iftype iftype;
+	bool reserved, radar_required, done;
+	enum {
+		CHANCTX_ITER_POS_ASSIGNED,
+		CHANCTX_ITER_POS_RESERVED,
+		CHANCTX_ITER_POS_DONE,
+	} per_link;
+};
+
+enum ieee80211_chanctx_iter_type {
+	CHANCTX_ITER_ALL,
+	CHANCTX_ITER_RESERVED,
+	CHANCTX_ITER_ASSIGNED,
+};
+
+static void ieee80211_chanctx_user_iter_next(struct ieee80211_local *local,
+					     struct ieee80211_chanctx *ctx,
+					     struct ieee80211_chanctx_user_iter *iter,
+					     enum ieee80211_chanctx_iter_type type,
+					     bool start)
+{
+	lockdep_assert_wiphy(local->hw.wiphy);
+
+	if (start) {
+		memset(iter, 0, sizeof(*iter));
+		goto next_interface;
+	}
+
+next_link:
+	for (int link_id = iter->link ? iter->link->link_id : 0;
+	     link_id < ARRAY_SIZE(iter->sdata->link);
+	     link_id++) {
+		struct ieee80211_link_data *link;
+
+		link = sdata_dereference(iter->sdata->link[link_id],
+					 iter->sdata);
+		if (!link)
+			continue;
+
+		switch (iter->per_link) {
+		case CHANCTX_ITER_POS_ASSIGNED:
+			iter->per_link = CHANCTX_ITER_POS_RESERVED;
+			if (type != CHANCTX_ITER_RESERVED &&
+			    rcu_access_pointer(link->conf->chanctx_conf) == &ctx->conf) {
+				iter->link = link;
+				iter->reserved = false;
+				iter->radar_required = link->radar_required;
+				iter->chanreq = &link->conf->chanreq;
+				return;
+			}
+			fallthrough;
+		case CHANCTX_ITER_POS_RESERVED:
+			iter->per_link = CHANCTX_ITER_POS_DONE;
+			if (type != CHANCTX_ITER_ASSIGNED &&
+			    link->reserved_chanctx == ctx) {
+				iter->link = link;
+				iter->reserved = true;
+				iter->radar_required =
+					link->reserved_radar_required;
+
+				iter->chanreq = &link->reserved;
+				return;
+			}
+			fallthrough;
+		case CHANCTX_ITER_POS_DONE:
+			iter->per_link = CHANCTX_ITER_POS_ASSIGNED;
+			continue;
+		}
+	}
+
+next_interface:
+	/* next (or first) interface */
+	iter->sdata = list_prepare_entry(iter->sdata, &local->interfaces, list);
+	list_for_each_entry_continue(iter->sdata, &local->interfaces, list) {
+		/* AP_VLAN has a chanctx pointer but follows AP */
+		if (iter->sdata->vif.type == NL80211_IFTYPE_AP_VLAN)
+			continue;
+
+		iter->link = NULL;
+		iter->per_link = CHANCTX_ITER_POS_ASSIGNED;
+		iter->iftype = iter->sdata->vif.type;
+		goto next_link;
+	}
+
+	iter->done = true;
+}
+
+#define for_each_chanctx_user_assigned(local, ctx, iter)		\
+	for (ieee80211_chanctx_user_iter_next(local, ctx, iter,		\
+					      CHANCTX_ITER_ASSIGNED,	\
+					      true);			\
+	     !((iter)->done);						\
+	     ieee80211_chanctx_user_iter_next(local, ctx, iter,		\
+					      CHANCTX_ITER_ASSIGNED,	\
+					      false))
+
+#define for_each_chanctx_user_reserved(local, ctx, iter)		\
+	for (ieee80211_chanctx_user_iter_next(local, ctx, iter,		\
+					      CHANCTX_ITER_RESERVED,	\
+					      true);			\
+	     !((iter)->done);						\
+	     ieee80211_chanctx_user_iter_next(local, ctx, iter,		\
+					      CHANCTX_ITER_RESERVED,	\
+					      false))
+
+#define for_each_chanctx_user_all(local, ctx, iter)			\
+	for (ieee80211_chanctx_user_iter_next(local, ctx, iter,		\
+					      CHANCTX_ITER_ALL,		\
+					      true);			\
+	     !((iter)->done);						\
+	     ieee80211_chanctx_user_iter_next(local, ctx, iter,		\
+					      CHANCTX_ITER_ALL,		\
+					      false))
+
 static int ieee80211_chanctx_num_assigned(struct ieee80211_local *local,
 					  struct ieee80211_chanctx *ctx)
 {
-	struct ieee80211_link_data *link;
+	struct ieee80211_chanctx_user_iter iter;
 	int num = 0;
 
-	lockdep_assert_wiphy(local->hw.wiphy);
-
-	for_each_sdata_link(local, link) {
-		if (rcu_access_pointer(link->conf->chanctx_conf) == &ctx->conf)
-			num++;
-	}
+	for_each_chanctx_user_assigned(local, ctx, &iter)
+		num++;
 
 	return num;
 }
@@ -31,15 +145,11 @@ static int ieee80211_chanctx_num_assigned(struct ieee80211_local *local,
 static int ieee80211_chanctx_num_reserved(struct ieee80211_local *local,
 					  struct ieee80211_chanctx *ctx)
 {
-	struct ieee80211_link_data *link;
+	struct ieee80211_chanctx_user_iter iter;
 	int num = 0;
 
-	lockdep_assert_wiphy(local->hw.wiphy);
-
-	for_each_sdata_link(local, link) {
-		if (link->reserved_chanctx == ctx)
-			num++;
-	}
+	for_each_chanctx_user_reserved(local, ctx, &iter)
+		num++;
 
 	return num;
 }
@@ -47,17 +157,11 @@ static int ieee80211_chanctx_num_reserved(struct ieee80211_local *local,
 int ieee80211_chanctx_refcount(struct ieee80211_local *local,
 			       struct ieee80211_chanctx *ctx)
 {
-	struct ieee80211_link_data *link;
+	struct ieee80211_chanctx_user_iter iter;
 	int num = 0;
 
-	lockdep_assert_wiphy(local->hw.wiphy);
-
-	for_each_sdata_link(local, link) {
-		if (rcu_access_pointer(link->conf->chanctx_conf) == &ctx->conf)
-			num++;
-		if (link->reserved_chanctx == ctx)
-			num++;
-	}
+	for_each_chanctx_user_all(local, ctx, &iter)
+		num++;
 
 	return num;
 }
@@ -158,18 +262,15 @@ ieee80211_chanctx_reserved_chanreq(struct ieee80211_local *local,
 				   const struct ieee80211_chan_req *req,
 				   struct ieee80211_chan_req *tmp)
 {
-	struct ieee80211_link_data *link;
+	struct ieee80211_chanctx_user_iter iter;
 
 	lockdep_assert_wiphy(local->hw.wiphy);
 
 	if (WARN_ON(!req))
 		return NULL;
 
-	for_each_sdata_link(local, link) {
-		if (link->reserved_chanctx != ctx)
-			continue;
-
-		req = ieee80211_chanreq_compatible(&link->reserved, req, tmp);
+	for_each_chanctx_user_reserved(local, ctx, &iter) {
+		req = ieee80211_chanreq_compatible(iter.chanreq, req, tmp);
 		if (!req)
 			break;
 	}
@@ -183,21 +284,16 @@ ieee80211_chanctx_non_reserved_chandef(struct ieee80211_local *local,
 				       const struct ieee80211_chan_req *compat,
 				       struct ieee80211_chan_req *tmp)
 {
-	struct ieee80211_link_data *link;
 	const struct ieee80211_chan_req *comp_def = compat;
+	struct ieee80211_chanctx_user_iter iter;
 
 	lockdep_assert_wiphy(local->hw.wiphy);
 
-	for_each_sdata_link(local, link) {
-		struct ieee80211_bss_conf *link_conf = link->conf;
-
-		if (rcu_access_pointer(link_conf->chanctx_conf) != &ctx->conf)
+	for_each_chanctx_user_assigned(local, ctx, &iter) {
+		if (iter.link->reserved_chanctx)
 			continue;
 
-		if (link->reserved_chanctx)
-			continue;
-
-		comp_def = ieee80211_chanreq_compatible(&link_conf->chanreq,
+		comp_def = ieee80211_chanreq_compatible(iter.chanreq,
 							comp_def, tmp);
 		if (!comp_def)
 			break;
@@ -702,17 +798,13 @@ static bool
 ieee80211_chanctx_radar_required(struct ieee80211_local *local,
 				 struct ieee80211_chanctx *ctx)
 {
-	struct ieee80211_chanctx_conf *conf = &ctx->conf;
-	struct ieee80211_link_data *link;
+	struct ieee80211_chanctx_user_iter iter;
 
 	lockdep_assert_wiphy(local->hw.wiphy);
 
-	for_each_sdata_link(local, link) {
-		if (rcu_access_pointer(link->conf->chanctx_conf) != conf)
-			continue;
-		if (!link->radar_required)
-			continue;
-		return true;
+	for_each_chanctx_user_assigned(local, ctx, &iter) {
+		if (iter.radar_required)
+			return true;
 	}
 
 	return false;
@@ -829,27 +921,17 @@ void ieee80211_recalc_chanctx_chantype(struct ieee80211_local *local,
 {
 	struct ieee80211_chanctx_conf *conf = &ctx->conf;
 	const struct ieee80211_chan_req *compat = NULL;
-	struct ieee80211_link_data *link;
+	struct ieee80211_chanctx_user_iter iter;
 	struct ieee80211_chan_req tmp;
 	struct sta_info *sta;
 
 	lockdep_assert_wiphy(local->hw.wiphy);
 
-	for_each_sdata_link(local, link) {
-		struct ieee80211_bss_conf *link_conf;
-
-		if (link->sdata->vif.type == NL80211_IFTYPE_AP_VLAN)
-			continue;
-
-		link_conf = link->conf;
-
-		if (rcu_access_pointer(link_conf->chanctx_conf) != conf)
-			continue;
-
+	for_each_chanctx_user_assigned(local, ctx, &iter) {
 		if (!compat)
-			compat = &link_conf->chanreq;
+			compat = iter.chanreq;
 
-		compat = ieee80211_chanreq_compatible(&link_conf->chanreq,
+		compat = ieee80211_chanreq_compatible(iter.chanreq,
 						      compat, &tmp);
 		if (WARN_ON_ONCE(!compat))
 			return;
@@ -862,6 +944,7 @@ void ieee80211_recalc_chanctx_chantype(struct ieee80211_local *local,
 	list_for_each_entry(sta, &local->sta_list, list) {
 		struct ieee80211_sub_if_data *sdata = sta->sdata;
 		struct ieee80211_chan_req tdls_chanreq = {};
+		struct ieee80211_link_data *link;
 		int tdls_link_id;
 
 		if (!sta->uploaded ||
@@ -992,21 +1075,21 @@ static int ieee80211_assign_link_chanctx(struct ieee80211_link_data *link,
 void ieee80211_recalc_smps_chanctx(struct ieee80211_local *local,
 				   struct ieee80211_chanctx *chanctx)
 {
+	struct ieee80211_chanctx_user_iter iter;
 	struct ieee80211_sub_if_data *sdata;
 	u8 rx_chains_static, rx_chains_dynamic;
-	struct ieee80211_link_data *link;
 
 	lockdep_assert_wiphy(local->hw.wiphy);
 
 	rx_chains_static = 1;
 	rx_chains_dynamic = 1;
 
-	for_each_sdata_link(local, link) {
+	for_each_chanctx_user_assigned(local, chanctx, &iter) {
 		u8 needed_static, needed_dynamic;
 
-		switch (link->sdata->vif.type) {
+		switch (iter.iftype) {
 		case NL80211_IFTYPE_STATION:
-			if (!link->sdata->u.mgd.associated)
+			if (!iter.sdata->u.mgd.associated)
 				continue;
 			break;
 		case NL80211_IFTYPE_MONITOR:
@@ -1022,26 +1105,23 @@ void ieee80211_recalc_smps_chanctx(struct ieee80211_local *local,
 			continue;
 		}
 
-		if (rcu_access_pointer(link->conf->chanctx_conf) != &chanctx->conf)
-			continue;
-
-		if (link->sdata->vif.type == NL80211_IFTYPE_MONITOR) {
+		if (iter.iftype == NL80211_IFTYPE_MONITOR) {
 			rx_chains_dynamic = rx_chains_static = local->rx_chains;
 			break;
 		}
 
-		switch (link->smps_mode) {
+		switch (iter.link->smps_mode) {
 		default:
 			WARN_ONCE(1, "Invalid SMPS mode %d\n",
-				  link->smps_mode);
+				  iter.link->smps_mode);
 			fallthrough;
 		case IEEE80211_SMPS_OFF:
-			needed_static = link->needed_rx_chains;
-			needed_dynamic = link->needed_rx_chains;
+			needed_static = iter.link->needed_rx_chains;
+			needed_dynamic = iter.link->needed_rx_chains;
 			break;
 		case IEEE80211_SMPS_DYNAMIC:
 			needed_static = 1;
-			needed_dynamic = link->needed_rx_chains;
+			needed_dynamic = iter.link->needed_rx_chains;
 			break;
 		case IEEE80211_SMPS_STATIC:
 			needed_static = 1;
@@ -1513,7 +1593,6 @@ static int ieee80211_chsw_switch_vifs(struct ieee80211_local *local,
 				      int n_vifs)
 {
 	struct ieee80211_vif_chanctx_switch *vif_chsw;
-	struct ieee80211_link_data *link;
 	struct ieee80211_chanctx *ctx, *old_ctx;
 	int i, err;
 
@@ -1525,6 +1604,8 @@ static int ieee80211_chsw_switch_vifs(struct ieee80211_local *local,
 
 	i = 0;
 	list_for_each_entry(ctx, &local->chanctx_list, list) {
+		struct ieee80211_chanctx_user_iter iter;
+
 		if (ctx->replace_state != IEEE80211_CHANCTX_REPLACES_OTHER)
 			continue;
 
@@ -1533,18 +1614,15 @@ static int ieee80211_chsw_switch_vifs(struct ieee80211_local *local,
 			goto out;
 		}
 
-		for_each_sdata_link(local, link) {
-			if (link->reserved_chanctx != ctx)
+		for_each_chanctx_user_reserved(local, ctx, &iter) {
+			if (!ieee80211_link_has_in_place_reservation(iter.link))
 				continue;
 
-			if (!ieee80211_link_has_in_place_reservation(link))
-				continue;
-
-			old_ctx = ieee80211_link_get_chanctx(link);
-			vif_chsw[i].vif = &link->sdata->vif;
+			old_ctx = ieee80211_link_get_chanctx(iter.link);
+			vif_chsw[i].vif = &iter.sdata->vif;
 			vif_chsw[i].old_ctx = &old_ctx->conf;
 			vif_chsw[i].new_ctx = &ctx->conf;
-			vif_chsw[i].link_conf = link->conf;
+			vif_chsw[i].link_conf = iter.link->conf;
 
 			i++;
 		}
@@ -1621,7 +1699,7 @@ static int ieee80211_vif_use_reserved_switch(struct ieee80211_local *local)
 	 */
 
 	list_for_each_entry(ctx, &local->chanctx_list, list) {
-		struct ieee80211_link_data *link;
+		struct ieee80211_chanctx_user_iter iter;
 
 		if (ctx->replace_state != IEEE80211_CHANCTX_REPLACES_OTHER)
 			continue;
@@ -1637,14 +1715,11 @@ static int ieee80211_vif_use_reserved_switch(struct ieee80211_local *local)
 		n_reserved = 0;
 		n_ready = 0;
 
-		for_each_sdata_link(local, link) {
-			if (rcu_access_pointer(link->conf->chanctx_conf) != &ctx->conf)
-				continue;
-
+		for_each_chanctx_user_assigned(local, ctx, &iter) {
 			n_assigned++;
-			if (link->reserved_chanctx) {
+			if (iter.link->reserved_chanctx) {
 				n_reserved++;
-				if (link->reserved_ready)
+				if (iter.link->reserved_ready)
 					n_ready++;
 			}
 		}
@@ -1661,15 +1736,12 @@ static int ieee80211_vif_use_reserved_switch(struct ieee80211_local *local)
 		}
 
 		ctx->conf.radar_enabled = false;
-		for_each_sdata_link(local, link) {
-			if (link->reserved_chanctx != ctx)
-				continue;
-
-			if (ieee80211_link_has_in_place_reservation(link) &&
-			    !link->reserved_ready)
+		for_each_chanctx_user_reserved(local, ctx, &iter) {
+			if (ieee80211_link_has_in_place_reservation(iter.link) &&
+			    !iter.link->reserved_ready)
 				return -EAGAIN;
 
-			old_ctx = ieee80211_link_get_chanctx(link);
+			old_ctx = ieee80211_link_get_chanctx(iter.link);
 			if (old_ctx) {
 				if (old_ctx->replace_state ==
 				    IEEE80211_CHANCTX_WILL_BE_REPLACED)
@@ -1680,7 +1752,7 @@ static int ieee80211_vif_use_reserved_switch(struct ieee80211_local *local)
 				n_vifs_ctxless++;
 			}
 
-			if (link->reserved_radar_required)
+			if (iter.radar_required)
 				ctx->conf.radar_enabled = true;
 		}
 	}
@@ -1695,7 +1767,7 @@ static int ieee80211_vif_use_reserved_switch(struct ieee80211_local *local)
 
 	/* update station rate control and min width before switch */
 	list_for_each_entry(ctx, &local->chanctx_list, list) {
-		struct ieee80211_link_data *link;
+		struct ieee80211_chanctx_user_iter iter;
 
 		if (ctx->replace_state != IEEE80211_CHANCTX_REPLACES_OTHER)
 			continue;
@@ -1705,15 +1777,12 @@ static int ieee80211_vif_use_reserved_switch(struct ieee80211_local *local)
 			goto err;
 		}
 
-		for_each_sdata_link(local, link) {
-			if (link->reserved_chanctx != ctx)
-				continue;
-
-			if (!ieee80211_link_has_in_place_reservation(link))
+		for_each_chanctx_user_reserved(local, ctx, &iter) {
+			if (!ieee80211_link_has_in_place_reservation(iter.link))
 				continue;
 
 			ieee80211_chan_bw_change(local,
-						 ieee80211_link_get_chanctx(link),
+						 ieee80211_link_get_chanctx(iter.link),
 						 true, true);
 		}
 
@@ -1742,7 +1811,7 @@ static int ieee80211_vif_use_reserved_switch(struct ieee80211_local *local)
 	 * context(s).
 	 */
 	list_for_each_entry(ctx, &local->chanctx_list, list) {
-		struct ieee80211_link_data *link;
+		struct ieee80211_chanctx_user_iter iter;
 
 		if (ctx->replace_state != IEEE80211_CHANCTX_REPLACES_OTHER)
 			continue;
@@ -1752,14 +1821,12 @@ static int ieee80211_vif_use_reserved_switch(struct ieee80211_local *local)
 			goto err;
 		}
 
-		for_each_sdata_link(local, link) {
-			struct ieee80211_sub_if_data *sdata = link->sdata;
+		for_each_chanctx_user_reserved(local, ctx, &iter) {
+			struct ieee80211_link_data *link = iter.link;
+			struct ieee80211_sub_if_data *sdata = iter.sdata;
 			struct ieee80211_bss_conf *link_conf = link->conf;
 			u64 changed = 0;
 
-			if (link->reserved_chanctx != ctx)
-				continue;
-
 			if (!ieee80211_link_has_in_place_reservation(link))
 				continue;
 
@@ -1772,9 +1839,9 @@ static int ieee80211_vif_use_reserved_switch(struct ieee80211_local *local)
 
 			ieee80211_check_fast_xmit_iface(sdata);
 
-			link->radar_required = link->reserved_radar_required;
+			link->radar_required = iter.radar_required;
 
-			if (link_conf->chanreq.oper.width != link->reserved.oper.width)
+			if (link_conf->chanreq.oper.width != iter.chanreq->oper.width)
 				changed = BSS_CHANGED_BANDWIDTH;
 
 			ieee80211_link_update_chanreq(link, &link->reserved);
@@ -1791,16 +1858,13 @@ static int ieee80211_vif_use_reserved_switch(struct ieee80211_local *local)
 		ieee80211_recalc_radar_chanctx(local, ctx);
 		ieee80211_recalc_chanctx_min_def(local, ctx);
 
-		for_each_sdata_link(local, link) {
-			if (link->reserved_chanctx != ctx)
+		for_each_chanctx_user_reserved(local, ctx, &iter) {
+			if (ieee80211_link_get_chanctx(iter.link) != ctx)
 				continue;
 
-			if (ieee80211_link_get_chanctx(link) != ctx)
-				continue;
+			iter.link->reserved_chanctx = NULL;
 
-			link->reserved_chanctx = NULL;
-
-			ieee80211_link_chanctx_reservation_complete(link);
+			ieee80211_link_chanctx_reservation_complete(iter.link);
 			ieee80211_chan_bw_change(local, ctx, false, false);
 		}
 
@@ -1811,9 +1875,8 @@ static int ieee80211_vif_use_reserved_switch(struct ieee80211_local *local)
 		 * reservation for originally requested interface has already
 		 * succeeded at this point.
 		 */
-		for_each_sdata_link(local, link) {
-			if (link->reserved_chanctx != ctx)
-				continue;
+		for_each_chanctx_user_reserved(local, ctx, &iter) {
+			struct ieee80211_link_data *link = iter.link;
 
 			if (WARN_ON(ieee80211_link_has_in_place_reservation(link)))
 				continue;
@@ -1858,17 +1921,14 @@ static int ieee80211_vif_use_reserved_switch(struct ieee80211_local *local)
 
 err:
 	list_for_each_entry(ctx, &local->chanctx_list, list) {
-		struct ieee80211_link_data *link;
+		struct ieee80211_chanctx_user_iter iter;
 
 		if (ctx->replace_state != IEEE80211_CHANCTX_REPLACES_OTHER)
 			continue;
 
-		for_each_sdata_link(local, link) {
-			if (link->reserved_chanctx != ctx)
-				continue;
-
-			ieee80211_link_unreserve_chanctx(link);
-			ieee80211_link_chanctx_reservation_complete(link);
+		for_each_chanctx_user_reserved(local, ctx, &iter) {
+			ieee80211_link_unreserve_chanctx(iter.link);
+			ieee80211_link_chanctx_reservation_complete(iter.link);
 		}
 	}
 
@@ -2071,29 +2131,17 @@ ieee80211_chanctx_recheck(struct ieee80211_local *local,
 			  struct ieee80211_chan_req *tmp)
 {
 	const struct ieee80211_chan_req *ret = req;
-	struct ieee80211_link_data *link;
+	struct ieee80211_chanctx_user_iter iter;
 
 	lockdep_assert_wiphy(local->hw.wiphy);
 
-	for_each_sdata_link(local, link) {
-		if (link == skip_link)
+	for_each_chanctx_user_all(local, ctx, &iter) {
+		if (iter.link == skip_link)
 			continue;
 
-		if (rcu_access_pointer(link->conf->chanctx_conf) == &ctx->conf) {
-			ret = ieee80211_chanreq_compatible(ret,
-							   &link->conf->chanreq,
-							   tmp);
-			if (!ret)
-				return NULL;
-		}
-
-		if (link->reserved_chanctx == ctx) {
-			ret = ieee80211_chanreq_compatible(ret,
-							   &link->reserved,
-							   tmp);
-			if (!ret)
-				return NULL;
-		}
+		ret = ieee80211_chanreq_compatible(ret, iter.chanreq, tmp);
+		if (!ret)
+			return NULL;
 	}
 
 	*tmp = *ret;
-- 
2.51.1