Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next

Pull networking updates from David Miller:
 "Highlights:

   1) Steady transitioning of the BPF instructure to a generic spot so
      all kernel subsystems can make use of it, from Alexei Starovoitov.

   2) SFC driver supports busy polling, from Alexandre Rames.

   3) Take advantage of hash table in UDP multicast delivery, from David
      Held.

   4) Lighten locking, in particular by getting rid of the LRU lists, in
      inet frag handling.  From Florian Westphal.

   5) Add support for various RFC6458 control messages in SCTP, from
      Geir Ola Vaagland.

   6) Allow to filter bridge forwarding database dumps by device, from
      Jamal Hadi Salim.

   7) virtio-net also now supports busy polling, from Jason Wang.

   8) Some low level optimization tweaks in pktgen from Jesper Dangaard
      Brouer.

   9) Add support for ipv6 address generation modes, so that userland
      can have some input into the process.  From Jiri Pirko.

  10) Consolidate common TCP connection request code in ipv4 and ipv6,
      from Octavian Purdila.

  11) New ARP packet logger in netfilter, from Pablo Neira Ayuso.

  12) Generic resizable RCU hash table, with intial users in netlink and
      nftables.  From Thomas Graf.

  13) Maintain a name assignment type so that userspace can see where a
      network device name came from (enumerated by kernel, assigned
      explicitly by userspace, etc.) From Tom Gundersen.

  14) Automatic flow label generation on transmit in ipv6, from Tom
      Herbert.

  15) New packet timestamping facilities from Willem de Bruijn, meant to
      assist in measuring latencies going into/out-of the packet
      scheduler, latency from TCP data transmission to ACK, etc"

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next: (1536 commits)
  cxgb4 : Disable recursive mailbox commands when enabling vi
  net: reduce USB network driver config options.
  tg3: Modify tg3_tso_bug() to handle multiple TX rings
  amd-xgbe: Perform phy connect/disconnect at dev open/stop
  amd-xgbe: Use dma_set_mask_and_coherent to set DMA mask
  net: sun4i-emac: fix memory leak on bad packet
  sctp: fix possible seqlock seadlock in sctp_packet_transmit()
  Revert "net: phy: Set the driver when registering an MDIO bus device"
  cxgb4vf: Turn off SGE RX/TX Callback Timers and interrupts in PCI shutdown routine
  team: Simplify return path of team_newlink
  bridge: Update outdated comment on promiscuous mode
  net-timestamp: ACK timestamp for bytestreams
  net-timestamp: TCP timestamping
  net-timestamp: SCHED timestamp on entering packet scheduler
  net-timestamp: add key to disambiguate concurrent datagrams
  net-timestamp: move timestamp flags out of sk_flags
  net-timestamp: extend SCM_TIMESTAMPING ancillary data struct
  cxgb4i : Move stray CPL definitions to cxgb4 driver
  tcp: reduce spurious retransmits due to transient SACK reneging
  qlcnic: Initialize dcbnl_ops before register_netdev
  ...

1 files changed, 716 insertions, 145 deletions

diff --git a/net/mac80211/chan.c b/net/mac80211/chan.c
index a310e33972de..6d537f03c0ba 100644
--- a/net/mac80211/chan.c
+++ b/net/mac80211/chan.c
@@ -63,6 +63,20 @@ static bool ieee80211_can_create_new_chanctx(struct ieee80211_local *local)
 	return ieee80211_num_chanctx(local) < ieee80211_max_num_channels(local);
 }
 
+static struct ieee80211_chanctx *
+ieee80211_vif_get_chanctx(struct ieee80211_sub_if_data *sdata)
+{
+	struct ieee80211_local *local __maybe_unused = sdata->local;
+	struct ieee80211_chanctx_conf *conf;
+
+	conf = rcu_dereference_protected(sdata->vif.chanctx_conf,
+					 lockdep_is_held(&local->chanctx_mtx));
+	if (!conf)
+		return NULL;
+
+	return container_of(conf, struct ieee80211_chanctx, conf);
+}
+
 static const struct cfg80211_chan_def *
 ieee80211_chanctx_reserved_chandef(struct ieee80211_local *local,
 				   struct ieee80211_chanctx *ctx,
@@ -160,6 +174,9 @@ ieee80211_find_reservation_chanctx(struct ieee80211_local *local,
 		return NULL;
 
 	list_for_each_entry(ctx, &local->chanctx_list, list) {
+		if (ctx->replace_state == IEEE80211_CHANCTX_WILL_BE_REPLACED)
+			continue;
+
 		if (ctx->mode == IEEE80211_CHANCTX_EXCLUSIVE)
 			continue;
 
@@ -347,6 +364,9 @@ ieee80211_find_chanctx(struct ieee80211_local *local,
 	list_for_each_entry(ctx, &local->chanctx_list, list) {
 		const struct cfg80211_chan_def *compat;
 
+		if (ctx->replace_state != IEEE80211_CHANCTX_REPLACE_NONE)
+			continue;
+
 		if (ctx->mode == IEEE80211_CHANCTX_EXCLUSIVE)
 			continue;
 
@@ -622,6 +642,7 @@ static void __ieee80211_vif_release_channel(struct ieee80211_sub_if_data *sdata)
 	struct ieee80211_local *local = sdata->local;
 	struct ieee80211_chanctx_conf *conf;
 	struct ieee80211_chanctx *ctx;
+	bool use_reserved_switch = false;
 
 	lockdep_assert_held(&local->chanctx_mtx);
 
@@ -632,12 +653,23 @@ static void __ieee80211_vif_release_channel(struct ieee80211_sub_if_data *sdata)
 
 	ctx = container_of(conf, struct ieee80211_chanctx, conf);
 
-	if (sdata->reserved_chanctx)
+	if (sdata->reserved_chanctx) {
+		if (sdata->reserved_chanctx->replace_state ==
+		    IEEE80211_CHANCTX_REPLACES_OTHER &&
+		    ieee80211_chanctx_num_reserved(local,
+						   sdata->reserved_chanctx) > 1)
+			use_reserved_switch = true;
+
 		ieee80211_vif_unreserve_chanctx(sdata);
+	}
 
 	ieee80211_assign_vif_chanctx(sdata, NULL);
 	if (ieee80211_chanctx_refcount(local, ctx) == 0)
 		ieee80211_free_chanctx(local, ctx);
+
+	/* Unreserving may ready an in-place reservation. */
+	if (use_reserved_switch)
+		ieee80211_vif_use_reserved_switch(local);
 }
 
 void ieee80211_recalc_smps_chanctx(struct ieee80211_local *local,
@@ -787,70 +819,6 @@ int ieee80211_vif_use_channel(struct ieee80211_sub_if_data *sdata,
 	return ret;
 }
 
-static int __ieee80211_vif_change_channel(struct ieee80211_sub_if_data *sdata,
-					  struct ieee80211_chanctx *ctx,
-					  u32 *changed)
-{
-	struct ieee80211_local *local = sdata->local;
-	const struct cfg80211_chan_def *chandef = &sdata->csa_chandef;
-	u32 chanctx_changed = 0;
-
-	if (!cfg80211_chandef_usable(sdata->local->hw.wiphy, chandef,
-				     IEEE80211_CHAN_DISABLED))
-		return -EINVAL;
-
-	if (ieee80211_chanctx_refcount(local, ctx) != 1)
-		return -EINVAL;
-
-	if (sdata->vif.bss_conf.chandef.width != chandef->width) {
-		chanctx_changed = IEEE80211_CHANCTX_CHANGE_WIDTH;
-		*changed |= BSS_CHANGED_BANDWIDTH;
-	}
-
-	sdata->vif.bss_conf.chandef = *chandef;
-	ctx->conf.def = *chandef;
-
-	chanctx_changed |= IEEE80211_CHANCTX_CHANGE_CHANNEL;
-	drv_change_chanctx(local, ctx, chanctx_changed);
-
-	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);
-
-	return 0;
-}
-
-int ieee80211_vif_change_channel(struct ieee80211_sub_if_data *sdata,
-				 u32 *changed)
-{
-	struct ieee80211_local *local = sdata->local;
-	struct ieee80211_chanctx_conf *conf;
-	struct ieee80211_chanctx *ctx;
-	int ret;
-
-	lockdep_assert_held(&local->mtx);
-
-	/* should never be called if not performing a channel switch. */
-	if (WARN_ON(!sdata->vif.csa_active))
-		return -EINVAL;
-
-	mutex_lock(&local->chanctx_mtx);
-	conf = rcu_dereference_protected(sdata->vif.chanctx_conf,
-					 lockdep_is_held(&local->chanctx_mtx));
-	if (!conf) {
-		ret = -EINVAL;
-		goto out;
-	}
-
-	ctx = container_of(conf, struct ieee80211_chanctx, conf);
-
-	ret = __ieee80211_vif_change_channel(sdata, ctx, changed);
- out:
-	mutex_unlock(&local->chanctx_mtx);
-	return ret;
-}
-
 static void
 __ieee80211_vif_copy_chanctx_to_vlans(struct ieee80211_sub_if_data *sdata,
 				      bool clear)
@@ -905,8 +873,25 @@ int ieee80211_vif_unreserve_chanctx(struct ieee80211_sub_if_data *sdata)
 	list_del(&sdata->reserved_chanctx_list);
 	sdata->reserved_chanctx = NULL;
 
-	if (ieee80211_chanctx_refcount(sdata->local, ctx) == 0)
-		ieee80211_free_chanctx(sdata->local, ctx);
+	if (ieee80211_chanctx_refcount(sdata->local, ctx) == 0) {
+		if (ctx->replace_state == IEEE80211_CHANCTX_REPLACES_OTHER) {
+			if (WARN_ON(!ctx->replace_ctx))
+				return -EINVAL;
+
+			WARN_ON(ctx->replace_ctx->replace_state !=
+			        IEEE80211_CHANCTX_WILL_BE_REPLACED);
+			WARN_ON(ctx->replace_ctx->replace_ctx != ctx);
+
+			ctx->replace_ctx->replace_ctx = NULL;
+			ctx->replace_ctx->replace_state =
+					IEEE80211_CHANCTX_REPLACE_NONE;
+
+			list_del_rcu(&ctx->list);
+			kfree_rcu(ctx, rcu_head);
+		} else {
+			ieee80211_free_chanctx(sdata->local, ctx);
+		}
+	}
 
 	return 0;
 }
@@ -917,40 +902,84 @@ int ieee80211_vif_reserve_chanctx(struct ieee80211_sub_if_data *sdata,
 				  bool radar_required)
 {
 	struct ieee80211_local *local = sdata->local;
-	struct ieee80211_chanctx_conf *conf;
-	struct ieee80211_chanctx *new_ctx, *curr_ctx;
-	int ret = 0;
+	struct ieee80211_chanctx *new_ctx, *curr_ctx, *ctx;
 
-	mutex_lock(&local->chanctx_mtx);
-
-	conf = rcu_dereference_protected(sdata->vif.chanctx_conf,
-					 lockdep_is_held(&local->chanctx_mtx));
-	if (!conf) {
-		ret = -EINVAL;
-		goto out;
-	}
+	lockdep_assert_held(&local->chanctx_mtx);
 
-	curr_ctx = container_of(conf, struct ieee80211_chanctx, conf);
+	curr_ctx = ieee80211_vif_get_chanctx(sdata);
+	if (curr_ctx && local->use_chanctx && !local->ops->switch_vif_chanctx)
+		return -ENOTSUPP;
 
 	new_ctx = ieee80211_find_reservation_chanctx(local, chandef, mode);
 	if (!new_ctx) {
-		if (ieee80211_chanctx_refcount(local, curr_ctx) == 1 &&
-		    (local->hw.flags & IEEE80211_HW_CHANGE_RUNNING_CHANCTX)) {
-			/* if we're the only users of the chanctx and
-			 * the driver supports changing a running
-			 * context, reserve our current context
-			 */
-			new_ctx = curr_ctx;
-		} else if (ieee80211_can_create_new_chanctx(local)) {
-			/* create a new context and reserve it */
+		if (ieee80211_can_create_new_chanctx(local)) {
 			new_ctx = ieee80211_new_chanctx(local, chandef, mode);
-			if (IS_ERR(new_ctx)) {
-				ret = PTR_ERR(new_ctx);
-				goto out;
-			}
+			if (IS_ERR(new_ctx))
+				return PTR_ERR(new_ctx);
 		} else {
-			ret = -EBUSY;
-			goto out;
+			if (!curr_ctx ||
+			    (curr_ctx->replace_state ==
+			     IEEE80211_CHANCTX_WILL_BE_REPLACED) ||
+			    !list_empty(&curr_ctx->reserved_vifs)) {
+				/*
+				 * Another vif already requested this context
+				 * for a reservation. Find another one hoping
+				 * all vifs assigned to it will also switch
+				 * soon enough.
+				 *
+				 * TODO: This needs a little more work as some
+				 * cases (more than 2 chanctx capable devices)
+				 * may fail which could otherwise succeed
+				 * provided some channel context juggling was
+				 * performed.
+				 *
+				 * Consider ctx1..3, vif1..6, each ctx has 2
+				 * vifs. vif1 and vif2 from ctx1 request new
+				 * different chandefs starting 2 in-place
+				 * reserations with ctx4 and ctx5 replacing
+				 * ctx1 and ctx2 respectively. Next vif5 and
+				 * vif6 from ctx3 reserve ctx4. If vif3 and
+				 * vif4 remain on ctx2 as they are then this
+				 * fails unless `replace_ctx` from ctx5 is
+				 * replaced with ctx3.
+				 */
+				list_for_each_entry(ctx, &local->chanctx_list,
+						    list) {
+					if (ctx->replace_state !=
+					    IEEE80211_CHANCTX_REPLACE_NONE)
+						continue;
+
+					if (!list_empty(&ctx->reserved_vifs))
+						continue;
+
+					curr_ctx = ctx;
+					break;
+				}
+			}
+
+			/*
+			 * 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_vifs))
+				return -EBUSY;
+
+			new_ctx = ieee80211_alloc_chanctx(local, chandef, mode);
+			if (!new_ctx)
+				return -ENOMEM;
+
+			new_ctx->replace_ctx = curr_ctx;
+			new_ctx->replace_state =
+					IEEE80211_CHANCTX_REPLACES_OTHER;
+
+			curr_ctx->replace_ctx = new_ctx;
+			curr_ctx->replace_state =
+					IEEE80211_CHANCTX_WILL_BE_REPLACED;
+
+			list_add_rcu(&new_ctx->list, &local->chanctx_list);
 		}
 	}
 
@@ -958,82 +987,601 @@ int ieee80211_vif_reserve_chanctx(struct ieee80211_sub_if_data *sdata,
 	sdata->reserved_chanctx = new_ctx;
 	sdata->reserved_chandef = *chandef;
 	sdata->reserved_radar_required = radar_required;
-out:
-	mutex_unlock(&local->chanctx_mtx);
-	return ret;
+	sdata->reserved_ready = false;
+
+	return 0;
 }
 
-int ieee80211_vif_use_reserved_context(struct ieee80211_sub_if_data *sdata,
-				       u32 *changed)
+static void
+ieee80211_vif_chanctx_reservation_complete(struct ieee80211_sub_if_data *sdata)
 {
-	struct ieee80211_local *local = sdata->local;
-	struct ieee80211_chanctx *ctx;
-	struct ieee80211_chanctx *old_ctx;
-	struct ieee80211_chanctx_conf *conf;
-	int ret;
-	u32 tmp_changed = *changed;
+	switch (sdata->vif.type) {
+	case NL80211_IFTYPE_ADHOC:
+	case NL80211_IFTYPE_AP:
+	case NL80211_IFTYPE_MESH_POINT:
+		ieee80211_queue_work(&sdata->local->hw,
+				     &sdata->csa_finalize_work);
+		break;
+	case NL80211_IFTYPE_STATION:
+		ieee80211_queue_work(&sdata->local->hw,
+				     &sdata->u.mgd.chswitch_work);
+		break;
+	case NL80211_IFTYPE_UNSPECIFIED:
+	case NL80211_IFTYPE_AP_VLAN:
+	case NL80211_IFTYPE_WDS:
+	case NL80211_IFTYPE_MONITOR:
+	case NL80211_IFTYPE_P2P_CLIENT:
+	case NL80211_IFTYPE_P2P_GO:
+	case NL80211_IFTYPE_P2P_DEVICE:
+	case NUM_NL80211_IFTYPES:
+		WARN_ON(1);
+		break;
+	}
+}
 
-	/* TODO: need to recheck if the chandef is usable etc.? */
+static int
+ieee80211_vif_use_reserved_reassign(struct ieee80211_sub_if_data *sdata)
+{
+	struct ieee80211_local *local = sdata->local;
+	struct ieee80211_vif_chanctx_switch vif_chsw[1] = {};
+	struct ieee80211_chanctx *old_ctx, *new_ctx;
+	const struct cfg80211_chan_def *chandef;
+	u32 changed = 0;
+	int err;
 
 	lockdep_assert_held(&local->mtx);
+	lockdep_assert_held(&local->chanctx_mtx);
 
-	mutex_lock(&local->chanctx_mtx);
+	new_ctx = sdata->reserved_chanctx;
+	old_ctx = ieee80211_vif_get_chanctx(sdata);
 
-	ctx = sdata->reserved_chanctx;
-	if (WARN_ON(!ctx)) {
-		ret = -EINVAL;
-		goto out;
-	}
+	if (WARN_ON(!sdata->reserved_ready))
+		return -EBUSY;
+
+	if (WARN_ON(!new_ctx))
+		return -EINVAL;
+
+	if (WARN_ON(!old_ctx))
+		return -EINVAL;
+
+	if (WARN_ON(new_ctx->replace_state ==
+		    IEEE80211_CHANCTX_REPLACES_OTHER))
+		return -EINVAL;
+
+	chandef = ieee80211_chanctx_non_reserved_chandef(local, new_ctx,
+				&sdata->reserved_chandef);
+	if (WARN_ON(!chandef))
+		return -EINVAL;
+
+	vif_chsw[0].vif = &sdata->vif;
+	vif_chsw[0].old_ctx = &old_ctx->conf;
+	vif_chsw[0].new_ctx = &new_ctx->conf;
+
+	list_del(&sdata->reserved_chanctx_list);
+	sdata->reserved_chanctx = NULL;
+
+	err = drv_switch_vif_chanctx(local, vif_chsw, 1,
+				     CHANCTX_SWMODE_REASSIGN_VIF);
+	if (err) {
+		if (ieee80211_chanctx_refcount(local, new_ctx) == 0)
+			ieee80211_free_chanctx(local, new_ctx);
 
-	conf = rcu_dereference_protected(sdata->vif.chanctx_conf,
-					 lockdep_is_held(&local->chanctx_mtx));
-	if (!conf) {
-		ret = -EINVAL;
 		goto out;
 	}
 
-	old_ctx = container_of(conf, struct ieee80211_chanctx, conf);
+	list_move(&sdata->assigned_chanctx_list, &new_ctx->assigned_vifs);
+	rcu_assign_pointer(sdata->vif.chanctx_conf, &new_ctx->conf);
+
+	if (sdata->vif.type == NL80211_IFTYPE_AP)
+		__ieee80211_vif_copy_chanctx_to_vlans(sdata, false);
+
+	if (ieee80211_chanctx_refcount(local, old_ctx) == 0)
+		ieee80211_free_chanctx(local, old_ctx);
 
 	if (sdata->vif.bss_conf.chandef.width != sdata->reserved_chandef.width)
-		tmp_changed |= BSS_CHANGED_BANDWIDTH;
+		changed = BSS_CHANGED_BANDWIDTH;
 
 	sdata->vif.bss_conf.chandef = sdata->reserved_chandef;
 
-	/* unref our reservation */
-	sdata->reserved_chanctx = NULL;
-	sdata->radar_required = sdata->reserved_radar_required;
+	if (changed)
+		ieee80211_bss_info_change_notify(sdata, changed);
+
+out:
+	ieee80211_vif_chanctx_reservation_complete(sdata);
+	return err;
+}
+
+static int
+ieee80211_vif_use_reserved_assign(struct ieee80211_sub_if_data *sdata)
+{
+	struct ieee80211_local *local = sdata->local;
+	struct ieee80211_chanctx *old_ctx, *new_ctx;
+	const struct cfg80211_chan_def *chandef;
+	int err;
+
+	old_ctx = ieee80211_vif_get_chanctx(sdata);
+	new_ctx = sdata->reserved_chanctx;
+
+	if (WARN_ON(!sdata->reserved_ready))
+		return -EINVAL;
+
+	if (WARN_ON(old_ctx))
+		return -EINVAL;
+
+	if (WARN_ON(!new_ctx))
+		return -EINVAL;
+
+	if (WARN_ON(new_ctx->replace_state ==
+		    IEEE80211_CHANCTX_REPLACES_OTHER))
+		return -EINVAL;
+
+	chandef = ieee80211_chanctx_non_reserved_chandef(local, new_ctx,
+				&sdata->reserved_chandef);
+	if (WARN_ON(!chandef))
+		return -EINVAL;
+
 	list_del(&sdata->reserved_chanctx_list);
+	sdata->reserved_chanctx = NULL;
 
-	if (old_ctx == ctx) {
-		/* This is our own context, just change it */
-		ret = __ieee80211_vif_change_channel(sdata, old_ctx,
-						     &tmp_changed);
-		if (ret)
-			goto out;
-	} else {
-		ret = ieee80211_assign_vif_chanctx(sdata, ctx);
-		if (ieee80211_chanctx_refcount(local, old_ctx) == 0)
-			ieee80211_free_chanctx(local, old_ctx);
-		if (ret) {
-			/* if assign fails refcount stays the same */
-			if (ieee80211_chanctx_refcount(local, ctx) == 0)
-				ieee80211_free_chanctx(local, ctx);
+	err = ieee80211_assign_vif_chanctx(sdata, new_ctx);
+	if (err) {
+		if (ieee80211_chanctx_refcount(local, new_ctx) == 0)
+			ieee80211_free_chanctx(local, new_ctx);
+
+		goto out;
+	}
+
+out:
+	ieee80211_vif_chanctx_reservation_complete(sdata);
+	return err;
+}
+
+static bool
+ieee80211_vif_has_in_place_reservation(struct ieee80211_sub_if_data *sdata)
+{
+	struct ieee80211_chanctx *old_ctx, *new_ctx;
+
+	lockdep_assert_held(&sdata->local->chanctx_mtx);
+
+	new_ctx = sdata->reserved_chanctx;
+	old_ctx = ieee80211_vif_get_chanctx(sdata);
+
+	if (!old_ctx)
+		return false;
+
+	if (WARN_ON(!new_ctx))
+		return false;
+
+	if (old_ctx->replace_state != IEEE80211_CHANCTX_WILL_BE_REPLACED)
+		return false;
+
+	if (new_ctx->replace_state != IEEE80211_CHANCTX_REPLACES_OTHER)
+		return false;
+
+	return true;
+}
+
+static int ieee80211_chsw_switch_hwconf(struct ieee80211_local *local,
+					struct ieee80211_chanctx *new_ctx)
+{
+	const struct cfg80211_chan_def *chandef;
+
+	lockdep_assert_held(&local->mtx);
+	lockdep_assert_held(&local->chanctx_mtx);
+
+	chandef = ieee80211_chanctx_reserved_chandef(local, new_ctx, NULL);
+	if (WARN_ON(!chandef))
+		return -EINVAL;
+
+	local->hw.conf.radar_enabled = new_ctx->conf.radar_enabled;
+	local->_oper_chandef = *chandef;
+	ieee80211_hw_config(local, 0);
+
+	return 0;
+}
+
+static int ieee80211_chsw_switch_vifs(struct ieee80211_local *local,
+				      int n_vifs)
+{
+	struct ieee80211_vif_chanctx_switch *vif_chsw;
+	struct ieee80211_sub_if_data *sdata;
+	struct ieee80211_chanctx *ctx, *old_ctx;
+	int i, err;
+
+	lockdep_assert_held(&local->mtx);
+	lockdep_assert_held(&local->chanctx_mtx);
+
+	vif_chsw = kzalloc(sizeof(vif_chsw[0]) * n_vifs, GFP_KERNEL);
+	if (!vif_chsw)
+		return -ENOMEM;
+
+	i = 0;
+	list_for_each_entry(ctx, &local->chanctx_list, list) {
+		if (ctx->replace_state != IEEE80211_CHANCTX_REPLACES_OTHER)
+			continue;
+
+		if (WARN_ON(!ctx->replace_ctx)) {
+			err = -EINVAL;
 			goto out;
 		}
 
-		if (sdata->vif.type == NL80211_IFTYPE_AP)
-			__ieee80211_vif_copy_chanctx_to_vlans(sdata, false);
+		list_for_each_entry(sdata, &ctx->reserved_vifs,
+				    reserved_chanctx_list) {
+			if (!ieee80211_vif_has_in_place_reservation(
+					sdata))
+				continue;
+
+			old_ctx = ieee80211_vif_get_chanctx(sdata);
+			vif_chsw[i].vif = &sdata->vif;
+			vif_chsw[i].old_ctx = &old_ctx->conf;
+			vif_chsw[i].new_ctx = &ctx->conf;
+
+			i++;
+		}
 	}
 
-	*changed = tmp_changed;
+	err = drv_switch_vif_chanctx(local, vif_chsw, n_vifs,
+				     CHANCTX_SWMODE_SWAP_CONTEXTS);
 
-	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);
 out:
-	mutex_unlock(&local->chanctx_mtx);
-	return ret;
+	kfree(vif_chsw);
+	return err;
+}
+
+static int ieee80211_chsw_switch_ctxs(struct ieee80211_local *local)
+{
+	struct ieee80211_chanctx *ctx;
+	int err;
+
+	lockdep_assert_held(&local->mtx);
+	lockdep_assert_held(&local->chanctx_mtx);
+
+	list_for_each_entry(ctx, &local->chanctx_list, list) {
+		if (ctx->replace_state != IEEE80211_CHANCTX_REPLACES_OTHER)
+			continue;
+
+		if (!list_empty(&ctx->replace_ctx->assigned_vifs))
+			continue;
+
+		ieee80211_del_chanctx(local, ctx->replace_ctx);
+		err = ieee80211_add_chanctx(local, ctx);
+		if (err)
+			goto err;
+	}
+
+	return 0;
+
+err:
+	WARN_ON(ieee80211_add_chanctx(local, ctx));
+	list_for_each_entry_continue_reverse(ctx, &local->chanctx_list, list) {
+		if (ctx->replace_state != IEEE80211_CHANCTX_REPLACES_OTHER)
+			continue;
+
+		if (!list_empty(&ctx->replace_ctx->assigned_vifs))
+			continue;
+
+		ieee80211_del_chanctx(local, ctx);
+		WARN_ON(ieee80211_add_chanctx(local, ctx->replace_ctx));
+	}
+
+	return err;
+}
+
+int
+ieee80211_vif_use_reserved_switch(struct ieee80211_local *local)
+{
+	struct ieee80211_sub_if_data *sdata, *sdata_tmp;
+	struct ieee80211_chanctx *ctx, *ctx_tmp, *old_ctx;
+	struct ieee80211_chanctx *new_ctx = NULL;
+	int i, err, n_assigned, n_reserved, n_ready;
+	int n_ctx = 0, n_vifs_switch = 0, n_vifs_assign = 0, n_vifs_ctxless = 0;
+
+	lockdep_assert_held(&local->mtx);
+	lockdep_assert_held(&local->chanctx_mtx);
+
+	/*
+	 * If there are 2 independent pairs of channel contexts performing
+	 * cross-switch of their vifs this code will still wait until both are
+	 * ready even though it could be possible to switch one before the
+	 * other is ready.
+	 *
+	 * For practical reasons and code simplicity just do a single huge
+	 * switch.
+	 */
+
+	/*
+	 * Verify if the reservation is still feasible.
+	 *  - if it's not then disconnect
+	 *  - if it is but not all vifs necessary are ready then defer
+	 */
+
+	list_for_each_entry(ctx, &local->chanctx_list, list) {
+		if (ctx->replace_state != IEEE80211_CHANCTX_REPLACES_OTHER)
+			continue;
+
+		if (WARN_ON(!ctx->replace_ctx)) {
+			err = -EINVAL;
+			goto err;
+		}
+
+		if (!local->use_chanctx)
+			new_ctx = ctx;
+
+		n_ctx++;
+
+		n_assigned = 0;
+		n_reserved = 0;
+		n_ready = 0;
+
+		list_for_each_entry(sdata, &ctx->replace_ctx->assigned_vifs,
+				    assigned_chanctx_list) {
+			n_assigned++;
+			if (sdata->reserved_chanctx) {
+				n_reserved++;
+				if (sdata->reserved_ready)
+					n_ready++;
+			}
+		}
+
+		if (n_assigned != n_reserved) {
+			if (n_ready == n_reserved) {
+				wiphy_info(local->hw.wiphy,
+					   "channel context reservation cannot be finalized because some interfaces aren't switching\n");
+				err = -EBUSY;
+				goto err;
+			}
+
+			return -EAGAIN;
+		}
+
+		ctx->conf.radar_enabled = false;
+		list_for_each_entry(sdata, &ctx->reserved_vifs,
+				    reserved_chanctx_list) {
+			if (ieee80211_vif_has_in_place_reservation(sdata) &&
+			    !sdata->reserved_ready)
+				return -EAGAIN;
+
+			old_ctx = ieee80211_vif_get_chanctx(sdata);
+			if (old_ctx) {
+				if (old_ctx->replace_state ==
+				    IEEE80211_CHANCTX_WILL_BE_REPLACED)
+					n_vifs_switch++;
+				else
+					n_vifs_assign++;
+			} else {
+				n_vifs_ctxless++;
+			}
+
+			if (sdata->reserved_radar_required)
+				ctx->conf.radar_enabled = true;
+		}
+	}
+
+	if (WARN_ON(n_ctx == 0) ||
+	    WARN_ON(n_vifs_switch == 0 &&
+		    n_vifs_assign == 0 &&
+		    n_vifs_ctxless == 0) ||
+	    WARN_ON(n_ctx > 1 && !local->use_chanctx) ||
+	    WARN_ON(!new_ctx && !local->use_chanctx)) {
+		err = -EINVAL;
+		goto err;
+	}
+
+	/*
+	 * All necessary vifs are ready. Perform the switch now depending on
+	 * reservations and driver capabilities.
+	 */
+
+	if (local->use_chanctx) {
+		if (n_vifs_switch > 0) {
+			err = ieee80211_chsw_switch_vifs(local, n_vifs_switch);
+			if (err)
+				goto err;
+		}
+
+		if (n_vifs_assign > 0 || n_vifs_ctxless > 0) {
+			err = ieee80211_chsw_switch_ctxs(local);
+			if (err)
+				goto err;
+		}
+	} else {
+		err = ieee80211_chsw_switch_hwconf(local, new_ctx);
+		if (err)
+			goto err;
+	}
+
+	/*
+	 * Update all structures, values and pointers to point to new channel
+	 * context(s).
+	 */
+
+	i = 0;
+	list_for_each_entry(ctx, &local->chanctx_list, list) {
+		if (ctx->replace_state != IEEE80211_CHANCTX_REPLACES_OTHER)
+			continue;
+
+		if (WARN_ON(!ctx->replace_ctx)) {
+			err = -EINVAL;
+			goto err;
+		}
+
+		list_for_each_entry(sdata, &ctx->reserved_vifs,
+				    reserved_chanctx_list) {
+			u32 changed = 0;
+
+			if (!ieee80211_vif_has_in_place_reservation(sdata))
+				continue;
+
+			rcu_assign_pointer(sdata->vif.chanctx_conf, &ctx->conf);
+
+			if (sdata->vif.type == NL80211_IFTYPE_AP)
+				__ieee80211_vif_copy_chanctx_to_vlans(sdata,
+								      false);
+
+			sdata->radar_required = sdata->reserved_radar_required;
+
+			if (sdata->vif.bss_conf.chandef.width !=
+			    sdata->reserved_chandef.width)
+				changed = BSS_CHANGED_BANDWIDTH;
+
+			sdata->vif.bss_conf.chandef = sdata->reserved_chandef;
+			if (changed)
+				ieee80211_bss_info_change_notify(sdata,
+								 changed);
+
+			ieee80211_recalc_txpower(sdata);
+		}
+
+		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);
+
+		list_for_each_entry_safe(sdata, sdata_tmp, &ctx->reserved_vifs,
+					 reserved_chanctx_list) {
+			if (ieee80211_vif_get_chanctx(sdata) != ctx)
+				continue;
+
+			list_del(&sdata->reserved_chanctx_list);
+			list_move(&sdata->assigned_chanctx_list,
+				  &new_ctx->assigned_vifs);
+			sdata->reserved_chanctx = NULL;
+
+			ieee80211_vif_chanctx_reservation_complete(sdata);
+		}
+
+		/*
+		 * This context might have been a dependency for an already
+		 * ready re-assign reservation interface that was deferred. Do
+		 * not propagate error to the caller though. The in-place
+		 * reservation for originally requested interface has already
+		 * succeeded at this point.
+		 */
+		list_for_each_entry_safe(sdata, sdata_tmp, &ctx->reserved_vifs,
+					 reserved_chanctx_list) {
+			if (WARN_ON(ieee80211_vif_has_in_place_reservation(
+					sdata)))
+				continue;
+
+			if (WARN_ON(sdata->reserved_chanctx != ctx))
+				continue;
+
+			if (!sdata->reserved_ready)
+				continue;
+
+			if (ieee80211_vif_get_chanctx(sdata))
+				err = ieee80211_vif_use_reserved_reassign(
+						sdata);
+			else
+				err = ieee80211_vif_use_reserved_assign(sdata);
+
+			if (err) {
+				sdata_info(sdata,
+					   "failed to finalize (re-)assign reservation (err=%d)\n",
+					   err);
+				ieee80211_vif_unreserve_chanctx(sdata);
+				cfg80211_stop_iface(local->hw.wiphy,
+						    &sdata->wdev,
+						    GFP_KERNEL);
+			}
+		}
+	}
+
+	/*
+	 * Finally free old contexts
+	 */
+
+	list_for_each_entry_safe(ctx, ctx_tmp, &local->chanctx_list, list) {
+		if (ctx->replace_state != IEEE80211_CHANCTX_WILL_BE_REPLACED)
+			continue;
+
+		ctx->replace_ctx->replace_ctx = NULL;
+		ctx->replace_ctx->replace_state =
+				IEEE80211_CHANCTX_REPLACE_NONE;
+
+		list_del_rcu(&ctx->list);
+		kfree_rcu(ctx, rcu_head);
+	}
+
+	return 0;
+
+err:
+	list_for_each_entry(ctx, &local->chanctx_list, list) {
+		if (ctx->replace_state != IEEE80211_CHANCTX_REPLACES_OTHER)
+			continue;
+
+		list_for_each_entry_safe(sdata, sdata_tmp, &ctx->reserved_vifs,
+					 reserved_chanctx_list) {
+			ieee80211_vif_unreserve_chanctx(sdata);
+			ieee80211_vif_chanctx_reservation_complete(sdata);
+		}
+	}
+
+	return err;
+}
+
+int ieee80211_vif_use_reserved_context(struct ieee80211_sub_if_data *sdata)
+{
+	struct ieee80211_local *local = sdata->local;
+	struct ieee80211_chanctx *new_ctx;
+	struct ieee80211_chanctx *old_ctx;
+	int err;
+
+	lockdep_assert_held(&local->mtx);
+	lockdep_assert_held(&local->chanctx_mtx);
+
+	new_ctx = sdata->reserved_chanctx;
+	old_ctx = ieee80211_vif_get_chanctx(sdata);
+
+	if (WARN_ON(!new_ctx))
+		return -EINVAL;
+
+	if (WARN_ON(new_ctx->replace_state ==
+		    IEEE80211_CHANCTX_WILL_BE_REPLACED))
+		return -EINVAL;
+
+	if (WARN_ON(sdata->reserved_ready))
+		return -EINVAL;
+
+	sdata->reserved_ready = true;
+
+	if (new_ctx->replace_state == IEEE80211_CHANCTX_REPLACE_NONE) {
+		if (old_ctx)
+			err = ieee80211_vif_use_reserved_reassign(sdata);
+		else
+			err = ieee80211_vif_use_reserved_assign(sdata);
+
+		if (err)
+			return err;
+	}
+
+	/*
+	 * In-place reservation may need to be finalized now either if:
+	 *  a) sdata is taking part in the swapping itself and is the last one
+	 *  b) sdata has switched with a re-assign reservation to an existing
+	 *     context readying in-place switching of old_ctx
+	 *
+	 * In case of (b) do not propagate the error up because the requested
+	 * sdata already switched successfully. Just spill an extra warning.
+	 * The ieee80211_vif_use_reserved_switch() already stops all necessary
+	 * interfaces upon failure.
+	 */
+	if ((old_ctx &&
+	     old_ctx->replace_state == IEEE80211_CHANCTX_WILL_BE_REPLACED) ||
+	    new_ctx->replace_state == IEEE80211_CHANCTX_REPLACES_OTHER) {
+		err = ieee80211_vif_use_reserved_switch(local);
+		if (err && err != -EAGAIN) {
+			if (new_ctx->replace_state ==
+			    IEEE80211_CHANCTX_REPLACES_OTHER)
+				return err;
+
+			wiphy_info(local->hw.wiphy,
+				   "depending in-place reservation failed (err=%d)\n",
+				   err);
+		}
+	}
+
+	return 0;
 }
 
 int ieee80211_vif_change_bandwidth(struct ieee80211_sub_if_data *sdata,
@@ -1043,6 +1591,7 @@ int ieee80211_vif_change_bandwidth(struct ieee80211_sub_if_data *sdata,
 	struct ieee80211_local *local = sdata->local;
 	struct ieee80211_chanctx_conf *conf;
 	struct ieee80211_chanctx *ctx;
+	const struct cfg80211_chan_def *compat;
 	int ret;
 
 	if (!cfg80211_chandef_usable(sdata->local->hw.wiphy, chandef,
@@ -1069,11 +1618,33 @@ int ieee80211_vif_change_bandwidth(struct ieee80211_sub_if_data *sdata,
 	}
 
 	ctx = container_of(conf, struct ieee80211_chanctx, conf);
-	if (!cfg80211_chandef_compatible(&conf->def, chandef)) {
+
+	compat = cfg80211_chandef_compatible(&conf->def, chandef);
+	if (!compat) {
 		ret = -EINVAL;
 		goto out;
 	}
 
+	switch (ctx->replace_state) {
+	case IEEE80211_CHANCTX_REPLACE_NONE:
+		if (!ieee80211_chanctx_reserved_chandef(local, ctx, compat)) {
+			ret = -EBUSY;
+			goto out;
+		}
+		break;
+	case IEEE80211_CHANCTX_WILL_BE_REPLACED:
+		/* TODO: Perhaps the bandwith change could be treated as a
+		 * reservation itself? */
+		ret = -EBUSY;
+		goto out;
+	case IEEE80211_CHANCTX_REPLACES_OTHER:
+		/* channel context that is going to replace another channel
+		 * context doesn't really exist and shouldn't be assigned
+		 * anywhere yet */
+		WARN_ON(1);
+		break;
+	}
+
 	sdata->vif.bss_conf.chandef = *chandef;
 
 	ieee80211_recalc_chanctx_chantype(local, ctx);