Merge branch 'bridge-make-setlink-dellink-notifications-more-accurate'

Nikolay Aleksandrov says:

====================
bridge: make setlink/dellink notifications more accurate

Before this set the bridge would generate a notification on vlan add or del
even if they didn't actually do any changes, which confuses listeners and
is generally not preferred. We could also lose notifications on actual
changes if one adds a range of vlans and there's an error in the middle.
The problem with just breaking and returning an error is that we could
break existing user-space scripts which rely on the vlan delete to clear
all existing entries in the specified range and ignore the non-existing
errors (typically used to clear the current vlan config).
So in order to make the notifications more accurate while keeping backwards
compatibility we add a boolean that tracks if anything actually changed
during the config calls.

The vlan add is more difficult to fix because it always returns 0 even if
nothing changed, but we cannot use a specific error because the drivers
can return anything and we may mask it, also we'd need to update all places
that directly return the add result, thus to signal that a vlan was created
or updated and in order not to break overlapping vlan range add we pass
down the new boolean that tracks changes to the add functions to check
if anything was actually updated.

v6: moved "changed" in else branch in br|nbp_vlan_add, thanks to
    Toshiaki Makita and retested everything again
v5: fix br_vlan_add return (v1 leftover) spotted by Toshiaki Makita
v4: set changed always to false in the non-vlan config case and retested
v3: rebased to latest net-next and fixed non-vlan config functions reported
    by kbuild test bot
v2: pass changed down to vlan add instead of masking errors
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

net/bridge/br_netlink.c

@@ -506,8 +506,9 @@ int br_getlink(struct sk_buff *skb, u32 pid, u32 seq,
 }
 
 static int br_vlan_info(struct net_bridge *br, struct net_bridge_port *p,
-			int cmd, struct bridge_vlan_info *vinfo)
+			int cmd, struct bridge_vlan_info *vinfo, bool *changed)
 {
+	bool curr_change;
 	int err = 0;
 
 	switch (cmd) {
@@ -516,22 +517,27 @@ static int br_vlan_info(struct net_bridge *br, struct net_bridge_port *p,
 			/* if the MASTER flag is set this will act on the global
 			 * per-VLAN entry as well
 			 */
-			err = nbp_vlan_add(p, vinfo->vid, vinfo->flags);
-			if (err)
-				break;
+			err = nbp_vlan_add(p, vinfo->vid, vinfo->flags,
+					   &curr_change);
 		} else {
 			vinfo->flags |= BRIDGE_VLAN_INFO_BRENTRY;
-			err = br_vlan_add(br, vinfo->vid, vinfo->flags);
+			err = br_vlan_add(br, vinfo->vid, vinfo->flags,
+					  &curr_change);
 		}
+		if (curr_change)
+			*changed = true;
 		break;
 
 	case RTM_DELLINK:
 		if (p) {
-			nbp_vlan_delete(p, vinfo->vid);
-			if (vinfo->flags & BRIDGE_VLAN_INFO_MASTER)
-				br_vlan_delete(p->br, vinfo->vid);
-		} else {
-			br_vlan_delete(br, vinfo->vid);
+			if (!nbp_vlan_delete(p, vinfo->vid))
+				*changed = true;
+
+			if ((vinfo->flags & BRIDGE_VLAN_INFO_MASTER) &&
+			    !br_vlan_delete(p->br, vinfo->vid))
+				*changed = true;
+		} else if (!br_vlan_delete(br, vinfo->vid)) {
+			*changed = true;
 		}
 		break;
 	}
@@ -542,7 +548,8 @@ static int br_vlan_info(struct net_bridge *br, struct net_bridge_port *p,
 static int br_process_vlan_info(struct net_bridge *br,
 				struct net_bridge_port *p, int cmd,
 				struct bridge_vlan_info *vinfo_curr,
-				struct bridge_vlan_info **vinfo_last)
+				struct bridge_vlan_info **vinfo_last,
+				bool *changed)
 {
 	if (!vinfo_curr->vid || vinfo_curr->vid >= VLAN_VID_MASK)
 		return -EINVAL;
@@ -572,7 +579,7 @@ static int br_process_vlan_info(struct net_bridge *br,
 		       sizeof(struct bridge_vlan_info));
 		for (v = (*vinfo_last)->vid; v <= vinfo_curr->vid; v++) {
 			tmp_vinfo.vid = v;
-			err = br_vlan_info(br, p, cmd, &tmp_vinfo);
+			err = br_vlan_info(br, p, cmd, &tmp_vinfo, changed);
 			if (err)
 				break;
 		}
@@ -581,13 +588,13 @@ static int br_process_vlan_info(struct net_bridge *br,
 		return err;
 	}
 
-	return br_vlan_info(br, p, cmd, vinfo_curr);
+	return br_vlan_info(br, p, cmd, vinfo_curr, changed);
 }
 
 static int br_afspec(struct net_bridge *br,
 		     struct net_bridge_port *p,
 		     struct nlattr *af_spec,
-		     int cmd)
+		     int cmd, bool *changed)
 {
 	struct bridge_vlan_info *vinfo_curr = NULL;
 	struct bridge_vlan_info *vinfo_last = NULL;
@@ -607,7 +614,8 @@ static int br_afspec(struct net_bridge *br,
 				return err;
 			err = br_process_vlan_tunnel_info(br, p, cmd,
 							  &tinfo_curr,
-							  &tinfo_last);
+							  &tinfo_last,
+							  changed);
 			if (err)
 				return err;
 			break;
@@ -616,7 +624,7 @@ static int br_afspec(struct net_bridge *br,
 				return -EINVAL;
 			vinfo_curr = nla_data(attr);
 			err = br_process_vlan_info(br, p, cmd, vinfo_curr,
-						   &vinfo_last);
+						   &vinfo_last, changed);
 			if (err)
 				return err;
 			break;
@@ -804,6 +812,7 @@ int br_setlink(struct net_device *dev, struct nlmsghdr *nlh, u16 flags)
 	struct nlattr *afspec;
 	struct net_bridge_port *p;
 	struct nlattr *tb[IFLA_BRPORT_MAX + 1];
+	bool changed = false;
 	int err = 0;
 
 	protinfo = nlmsg_find_attr(nlh, sizeof(struct ifinfomsg), IFLA_PROTINFO);
@@ -839,14 +848,15 @@ int br_setlink(struct net_device *dev, struct nlmsghdr *nlh, u16 flags)
 		}
 		if (err)
 			goto out;
+		changed = true;
 	}
 
 	if (afspec) {
 		err = br_afspec((struct net_bridge *)netdev_priv(dev), p,
-				afspec, RTM_SETLINK);
+				afspec, RTM_SETLINK, &changed);
 	}
 
-	if (err == 0)
+	if (changed)
 		br_ifinfo_notify(RTM_NEWLINK, p);
 out:
 	return err;
@@ -857,6 +867,7 @@ int br_dellink(struct net_device *dev, struct nlmsghdr *nlh, u16 flags)
 {
 	struct nlattr *afspec;
 	struct net_bridge_port *p;
+	bool changed = false;
 	int err = 0;
 
 	afspec = nlmsg_find_attr(nlh, sizeof(struct ifinfomsg), IFLA_AF_SPEC);
@@ -869,8 +880,8 @@ int br_dellink(struct net_device *dev, struct nlmsghdr *nlh, u16 flags)
 		return -EINVAL;
 
 	err = br_afspec((struct net_bridge *)netdev_priv(dev), p,
-			afspec, RTM_DELLINK);
-	if (err == 0)
+			afspec, RTM_DELLINK, &changed);
+	if (changed)
 		/* Send RTM_NEWLINK because userspace
 		 * expects RTM_NEWLINK for vlan dels
 		 */

net/bridge/br_netlink_tunnel.c

@@ -198,7 +198,7 @@ static const struct nla_policy vlan_tunnel_policy[IFLA_BRIDGE_VLAN_TUNNEL_MAX +
 };
 
 static int br_vlan_tunnel_info(struct net_bridge_port *p, int cmd,
-			       u16 vid, u32 tun_id)
+			       u16 vid, u32 tun_id, bool *changed)
 {
 	int err = 0;
 
@@ -208,9 +208,12 @@ static int br_vlan_tunnel_info(struct net_bridge_port *p, int cmd,
 	switch (cmd) {
 	case RTM_SETLINK:
 		err = nbp_vlan_tunnel_info_add(p, vid, tun_id);
+		if (!err)
+			*changed = true;
 		break;
 	case RTM_DELLINK:
-		nbp_vlan_tunnel_info_delete(p, vid);
+		if (!nbp_vlan_tunnel_info_delete(p, vid))
+			*changed = true;
 		break;
 	}
 
@@ -254,7 +257,8 @@ int br_parse_vlan_tunnel_info(struct nlattr *attr,
 int br_process_vlan_tunnel_info(struct net_bridge *br,
 				struct net_bridge_port *p, int cmd,
 				struct vtunnel_info *tinfo_curr,
-				struct vtunnel_info *tinfo_last)
+				struct vtunnel_info *tinfo_last,
+				bool *changed)
 {
 	int err;
 
@@ -272,7 +276,7 @@ int br_process_vlan_tunnel_info(struct net_bridge *br,
 			return -EINVAL;
 		t = tinfo_last->tunid;
 		for (v = tinfo_last->vid; v <= tinfo_curr->vid; v++) {
-			err = br_vlan_tunnel_info(p, cmd, v, t);
+			err = br_vlan_tunnel_info(p, cmd, v, t, changed);
 			if (err)
 				return err;
 			t++;
@@ -283,7 +287,7 @@ int br_process_vlan_tunnel_info(struct net_bridge *br,
 		if (tinfo_last->flags)
 			return -EINVAL;
 		err = br_vlan_tunnel_info(p, cmd, tinfo_curr->vid,
-					  tinfo_curr->tunid);
+					  tinfo_curr->tunid, changed);
 		if (err)
 			return err;
 		memset(tinfo_last, 0, sizeof(struct vtunnel_info));

net/bridge/br_private.h

@@ -803,7 +803,8 @@ struct sk_buff *br_handle_vlan(struct net_bridge *br,
 			       const struct net_bridge_port *port,
 			       struct net_bridge_vlan_group *vg,
 			       struct sk_buff *skb);
-int br_vlan_add(struct net_bridge *br, u16 vid, u16 flags);
+int br_vlan_add(struct net_bridge *br, u16 vid, u16 flags,
+		bool *changed);
 int br_vlan_delete(struct net_bridge *br, u16 vid);
 void br_vlan_flush(struct net_bridge *br);
 struct net_bridge_vlan *br_vlan_find(struct net_bridge_vlan_group *vg, u16 vid);
@@ -816,7 +817,8 @@ int br_vlan_set_stats(struct net_bridge *br, unsigned long val);
 int br_vlan_init(struct net_bridge *br);
 int br_vlan_set_default_pvid(struct net_bridge *br, unsigned long val);
 int __br_vlan_set_default_pvid(struct net_bridge *br, u16 pvid);
-int nbp_vlan_add(struct net_bridge_port *port, u16 vid, u16 flags);
+int nbp_vlan_add(struct net_bridge_port *port, u16 vid, u16 flags,
+		 bool *changed);
 int nbp_vlan_delete(struct net_bridge_port *port, u16 vid);
 void nbp_vlan_flush(struct net_bridge_port *port);
 int nbp_vlan_init(struct net_bridge_port *port);
@@ -903,8 +905,10 @@ static inline struct sk_buff *br_handle_vlan(struct net_bridge *br,
 	return skb;
 }
 
-static inline int br_vlan_add(struct net_bridge *br, u16 vid, u16 flags)
+static inline int br_vlan_add(struct net_bridge *br, u16 vid, u16 flags,
+			      bool *changed)
 {
+	*changed = false;
 	return -EOPNOTSUPP;
 }
 
@@ -926,8 +930,10 @@ static inline int br_vlan_init(struct net_bridge *br)
 	return 0;
 }
 
-static inline int nbp_vlan_add(struct net_bridge_port *port, u16 vid, u16 flags)
+static inline int nbp_vlan_add(struct net_bridge_port *port, u16 vid, u16 flags,
+			       bool *changed)
 {
+	*changed = false;
 	return -EOPNOTSUPP;
 }
 

net/bridge/br_private_tunnel.h

@@ -26,7 +26,8 @@ int br_process_vlan_tunnel_info(struct net_bridge *br,
 				struct net_bridge_port *p,
 				int cmd,
 				struct vtunnel_info *tinfo_curr,
-				struct vtunnel_info *tinfo_last);
+				struct vtunnel_info *tinfo_last,
+				bool *changed);
 int br_get_vlan_tunnel_info_size(struct net_bridge_vlan_group *vg);
 int br_fill_vlan_tunnel_info(struct sk_buff *skb,
 			     struct net_bridge_vlan_group *vg);

net/bridge/br_vlan.c

@@ -32,27 +32,34 @@ static struct net_bridge_vlan *br_vlan_lookup(struct rhashtable *tbl, u16 vid)
 	return rhashtable_lookup_fast(tbl, &vid, br_vlan_rht_params);
 }
 
-static void __vlan_add_pvid(struct net_bridge_vlan_group *vg, u16 vid)
+static bool __vlan_add_pvid(struct net_bridge_vlan_group *vg, u16 vid)
 {
 	if (vg->pvid == vid)
-		return;
+		return false;
 
 	smp_wmb();
 	vg->pvid = vid;
+
+	return true;
 }
 
-static void __vlan_delete_pvid(struct net_bridge_vlan_group *vg, u16 vid)
+static bool __vlan_delete_pvid(struct net_bridge_vlan_group *vg, u16 vid)
 {
 	if (vg->pvid != vid)
-		return;
+		return false;
 
 	smp_wmb();
 	vg->pvid = 0;
+
+	return true;
 }
 
-static void __vlan_add_flags(struct net_bridge_vlan *v, u16 flags)
+/* return true if anything changed, false otherwise */
+static bool __vlan_add_flags(struct net_bridge_vlan *v, u16 flags)
 {
 	struct net_bridge_vlan_group *vg;
+	u16 old_flags = v->flags;
+	bool ret;
 
 	if (br_vlan_is_master(v))
 		vg = br_vlan_group(v->br);
@@ -60,14 +67,16 @@ static void __vlan_add_flags(struct net_bridge_vlan *v, u16 flags)
 		vg = nbp_vlan_group(v->port);
 
 	if (flags & BRIDGE_VLAN_INFO_PVID)
-		__vlan_add_pvid(vg, v->vid);
+		ret = __vlan_add_pvid(vg, v->vid);
 	else
-		__vlan_delete_pvid(vg, v->vid);
+		ret = __vlan_delete_pvid(vg, v->vid);
 
 	if (flags & BRIDGE_VLAN_INFO_UNTAGGED)
 		v->flags |= BRIDGE_VLAN_INFO_UNTAGGED;
 	else
 		v->flags &= ~BRIDGE_VLAN_INFO_UNTAGGED;
+
+	return ret || !!(old_flags ^ v->flags);
 }
 
 static int __vlan_vid_add(struct net_device *dev, struct net_bridge *br,
@@ -151,8 +160,10 @@ static struct net_bridge_vlan *br_vlan_get_master(struct net_bridge *br, u16 vid
 	vg = br_vlan_group(br);
 	masterv = br_vlan_find(vg, vid);
 	if (!masterv) {
+		bool changed;
+
 		/* missing global ctx, create it now */
-		if (br_vlan_add(br, vid, 0))
+		if (br_vlan_add(br, vid, 0, &changed))
 			return NULL;
 		masterv = br_vlan_find(vg, vid);
 		if (WARN_ON(!masterv))
@@ -232,8 +243,11 @@ static int __vlan_add(struct net_bridge_vlan *v, u16 flags)
 
 		/* need to work on the master vlan too */
 		if (flags & BRIDGE_VLAN_INFO_MASTER) {
-			err = br_vlan_add(br, v->vid, flags |
-						      BRIDGE_VLAN_INFO_BRENTRY);
+			bool changed;
+
+			err = br_vlan_add(br, v->vid,
+					  flags | BRIDGE_VLAN_INFO_BRENTRY,
+					  &changed);
 			if (err)
 				goto out_filt;
 		}
@@ -550,8 +564,9 @@ bool br_should_learn(struct net_bridge_port *p, struct sk_buff *skb, u16 *vid)
 
 /* Must be protected by RTNL.
  * Must be called with vid in range from 1 to 4094 inclusive.
+ * changed must be true only if the vlan was created or updated
  */
-int br_vlan_add(struct net_bridge *br, u16 vid, u16 flags)
+int br_vlan_add(struct net_bridge *br, u16 vid, u16 flags, bool *changed)
 {
 	struct net_bridge_vlan_group *vg;
 	struct net_bridge_vlan *vlan;
@@ -559,6 +574,7 @@ int br_vlan_add(struct net_bridge *br, u16 vid, u16 flags)
 
 	ASSERT_RTNL();
 
+	*changed = false;
 	vg = br_vlan_group(br);
 	vlan = br_vlan_find(vg, vid);
 	if (vlan) {
@@ -576,8 +592,11 @@ int br_vlan_add(struct net_bridge *br, u16 vid, u16 flags)
 			refcount_inc(&vlan->refcnt);
 			vlan->flags |= BRIDGE_VLAN_INFO_BRENTRY;
 			vg->num_vlans++;
+			*changed = true;
 		}
-		__vlan_add_flags(vlan, flags);
+		if (__vlan_add_flags(vlan, flags))
+			*changed = true;
+
 		return 0;
 	}
 
@@ -600,6 +619,8 @@ int br_vlan_add(struct net_bridge *br, u16 vid, u16 flags)
 	if (ret) {
 		free_percpu(vlan->stats);
 		kfree(vlan);
+	} else {
+		*changed = true;
 	}
 
 	return ret;
@@ -824,9 +845,10 @@ int __br_vlan_set_default_pvid(struct net_bridge *br, u16 pvid)
 	const struct net_bridge_vlan *pvent;
 	struct net_bridge_vlan_group *vg;
 	struct net_bridge_port *p;
+	unsigned long *changed;
+	bool vlchange;
 	u16 old_pvid;
 	int err = 0;
-	unsigned long *changed;
 
 	if (!pvid) {
 		br_vlan_disable_default_pvid(br);
@@ -850,7 +872,8 @@ int __br_vlan_set_default_pvid(struct net_bridge *br, u16 pvid)
 		err = br_vlan_add(br, pvid,
 				  BRIDGE_VLAN_INFO_PVID |
 				  BRIDGE_VLAN_INFO_UNTAGGED |
-				  BRIDGE_VLAN_INFO_BRENTRY);
+				  BRIDGE_VLAN_INFO_BRENTRY,
+				  &vlchange);
 		if (err)
 			goto out;
 		br_vlan_delete(br, old_pvid);
@@ -869,7 +892,8 @@ int __br_vlan_set_default_pvid(struct net_bridge *br, u16 pvid)
 
 		err = nbp_vlan_add(p, pvid,
 				   BRIDGE_VLAN_INFO_PVID |
-				   BRIDGE_VLAN_INFO_UNTAGGED);
+				   BRIDGE_VLAN_INFO_UNTAGGED,
+				   &vlchange);
 		if (err)
 			goto err_port;
 		nbp_vlan_delete(p, old_pvid);
@@ -890,7 +914,8 @@ err_port:
 		if (old_pvid)
 			nbp_vlan_add(p, old_pvid,
 				     BRIDGE_VLAN_INFO_PVID |
-				     BRIDGE_VLAN_INFO_UNTAGGED);
+				     BRIDGE_VLAN_INFO_UNTAGGED,
+				     &vlchange);
 		nbp_vlan_delete(p, pvid);
 	}
 
@@ -899,7 +924,8 @@ err_port:
 			br_vlan_add(br, old_pvid,
 				    BRIDGE_VLAN_INFO_PVID |
 				    BRIDGE_VLAN_INFO_UNTAGGED |
-				    BRIDGE_VLAN_INFO_BRENTRY);
+				    BRIDGE_VLAN_INFO_BRENTRY,
+				    &vlchange);
 		br_vlan_delete(br, pvid);
 	}
 	goto out;
@@ -931,6 +957,7 @@ int br_vlan_init(struct net_bridge *br)
 {
 	struct net_bridge_vlan_group *vg;
 	int ret = -ENOMEM;
+	bool changed;
 
 	vg = kzalloc(sizeof(*vg), GFP_KERNEL);
 	if (!vg)
@@ -947,7 +974,7 @@ int br_vlan_init(struct net_bridge *br)
 	rcu_assign_pointer(br->vlgrp, vg);
 	ret = br_vlan_add(br, 1,
 			  BRIDGE_VLAN_INFO_PVID | BRIDGE_VLAN_INFO_UNTAGGED |
-			  BRIDGE_VLAN_INFO_BRENTRY);
+			  BRIDGE_VLAN_INFO_BRENTRY, &changed);
 	if (ret)
 		goto err_vlan_add;
 
@@ -992,9 +1019,12 @@ int nbp_vlan_init(struct net_bridge_port *p)
 	INIT_LIST_HEAD(&vg->vlan_list);
 	rcu_assign_pointer(p->vlgrp, vg);
 	if (p->br->default_pvid) {
+		bool changed;
+
 		ret = nbp_vlan_add(p, p->br->default_pvid,
 				   BRIDGE_VLAN_INFO_PVID |
-				   BRIDGE_VLAN_INFO_UNTAGGED);
+				   BRIDGE_VLAN_INFO_UNTAGGED,
+				   &changed);
 		if (ret)
 			goto err_vlan_add;
 	}
@@ -1016,8 +1046,10 @@ err_vlan_enabled:
 
 /* Must be protected by RTNL.
  * Must be called with vid in range from 1 to 4094 inclusive.
+ * changed must be true only if the vlan was created or updated
  */
-int nbp_vlan_add(struct net_bridge_port *port, u16 vid, u16 flags)
+int nbp_vlan_add(struct net_bridge_port *port, u16 vid, u16 flags,
+		 bool *changed)
 {
 	struct switchdev_obj_port_vlan v = {
 		.obj.orig_dev = port->dev,
@@ -1031,13 +1063,15 @@ int nbp_vlan_add(struct net_bridge_port *port, u16 vid, u16 flags)
 
 	ASSERT_RTNL();
 
+	*changed = false;
 	vlan = br_vlan_find(nbp_vlan_group(port), vid);
 	if (vlan) {
 		/* Pass the flags to the hardware bridge */
 		ret = switchdev_port_obj_add(port->dev, &v.obj);
 		if (ret && ret != -EOPNOTSUPP)
 			return ret;
-		__vlan_add_flags(vlan, flags);
+		*changed = __vlan_add_flags(vlan, flags);
+
 		return 0;
 	}
 
@@ -1050,6 +1084,8 @@ int nbp_vlan_add(struct net_bridge_port *port, u16 vid, u16 flags)
 	ret = __vlan_add(vlan, flags);
 	if (ret)
 		kfree(vlan);
+	else
+		*changed = true;
 
 	return ret;
 }