vxlan: Allow vetoing of FDB notifications

Change vxlan_fdb_switchdev_call_notifiers() to return the result from
calling switchdev notifiers. Propagate the error number up the stack.

In vxlan_fdb_update_existing() and vxlan_fdb_update_create() add
rollbacks to clean up the work that was done before the veto.

Signed-off-by: Petr Machata <petrm@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/vxlan.c b/drivers/net/vxlan.c
index 1c8d8c8e09616004481f9e975aa99e3d0bb421e5..92904ee160537661f010b1d085c043f961e93017 100644 (file)
--- a/drivers/net/vxlan.c
+++ b/drivers/net/vxlan.c
@@ -375,32 +375,38 @@ static void vxlan_fdb_switchdev_notifier_info(const struct vxlan_dev *vxlan,
        fdb_info->added_by_user = fdb->flags & NTF_VXLAN_ADDED_BY_USER;
 }
 
-static void vxlan_fdb_switchdev_call_notifiers(struct vxlan_dev *vxlan,
-                                              struct vxlan_fdb *fdb,
-                                              struct vxlan_rdst *rd,
-                                              bool adding)
+static int vxlan_fdb_switchdev_call_notifiers(struct vxlan_dev *vxlan,
+                                             struct vxlan_fdb *fdb,
+                                             struct vxlan_rdst *rd,
+                                             bool adding)
 {
        struct switchdev_notifier_vxlan_fdb_info info;
        enum switchdev_notifier_type notifier_type;
+       int ret;
 
        if (WARN_ON(!rd))
-               return;
+               return 0;
 
        notifier_type = adding ? SWITCHDEV_VXLAN_FDB_ADD_TO_DEVICE
                               : SWITCHDEV_VXLAN_FDB_DEL_TO_DEVICE;
        vxlan_fdb_switchdev_notifier_info(vxlan, fdb, rd, &info);
-       call_switchdev_notifiers(notifier_type, vxlan->dev,
-                                &info.info);
+       ret = call_switchdev_notifiers(notifier_type, vxlan->dev,
+                                      &info.info);
+       return notifier_to_errno(ret);
 }
 
-static void vxlan_fdb_notify(struct vxlan_dev *vxlan, struct vxlan_fdb *fdb,
-                            struct vxlan_rdst *rd, int type, bool swdev_notify)
+static int vxlan_fdb_notify(struct vxlan_dev *vxlan, struct vxlan_fdb *fdb,
+                           struct vxlan_rdst *rd, int type, bool swdev_notify)
 {
+       int err;
+
        if (swdev_notify) {
                switch (type) {
                case RTM_NEWNEIGH:
-                       vxlan_fdb_switchdev_call_notifiers(vxlan, fdb, rd,
-                                                          true);
+                       err = vxlan_fdb_switchdev_call_notifiers(vxlan, fdb, rd,
+                                                                true);
+                       if (err)
+                               return err;
                        break;
                case RTM_DELNEIGH:
                        vxlan_fdb_switchdev_call_notifiers(vxlan, fdb, rd,
@@ -410,6 +416,7 @@ static void vxlan_fdb_notify(struct vxlan_dev *vxlan, struct vxlan_fdb *fdb,
        }
 
        __vxlan_fdb_notify(vxlan, fdb, rd, type);
+       return 0;
 }
 
 static void vxlan_ip_miss(struct net_device *dev, union vxlan_addr *ipa)
@@ -868,7 +875,8 @@ static int vxlan_fdb_update_existing(struct vxlan_dev *vxlan,
        struct vxlan_rdst *rd = NULL;
        struct vxlan_rdst oldrd;
        int notify = 0;
-       int rc;
+       int rc = 0;
+       int err;
 
        /* Do not allow an externally learned entry to take over an entry added
         * by the user.
@@ -915,10 +923,20 @@ static int vxlan_fdb_update_existing(struct vxlan_dev *vxlan,
                if (rd == NULL)
                        rd = first_remote_rtnl(f);
 
-               vxlan_fdb_notify(vxlan, f, rd, RTM_NEWNEIGH, swdev_notify);
+               err = vxlan_fdb_notify(vxlan, f, rd, RTM_NEWNEIGH,
+                                      swdev_notify);
+               if (err)
+                       goto err_notify;
        }
 
        return 0;
+
+err_notify:
+       if ((flags & NLM_F_REPLACE) && rc)
+               *rd = oldrd;
+       else if ((flags & NLM_F_APPEND) && rc)
+               list_del_rcu(&rd->list);
+       return err;
 }
 
 static int vxlan_fdb_update_create(struct vxlan_dev *vxlan,
@@ -943,9 +961,16 @@ static int vxlan_fdb_update_create(struct vxlan_dev *vxlan,
        if (rc < 0)
                return rc;
 
-       vxlan_fdb_notify(vxlan, f, first_remote_rtnl(f), RTM_NEWNEIGH,
-                        swdev_notify);
+       rc = vxlan_fdb_notify(vxlan, f, first_remote_rtnl(f), RTM_NEWNEIGH,
+                             swdev_notify);
+       if (rc)
+               goto err_notify;
+
        return 0;
+
+err_notify:
+       vxlan_fdb_destroy(vxlan, f, false, false);
+       return rc;
 }
 
 /* Add new entry to forwarding table -- assumes lock held */
@@ -3515,9 +3540,12 @@ static int __vxlan_dev_create(struct net *net, struct net_device *dev,
                goto errout;
 
        /* notify default fdb entry */
-       if (f)
-               vxlan_fdb_notify(vxlan, f, first_remote_rtnl(f), RTM_NEWNEIGH,
-                                true);
+       if (f) {
+               err = vxlan_fdb_notify(vxlan, f, first_remote_rtnl(f),
+                                      RTM_NEWNEIGH, true);
+               if (err)
+                       goto errout;
+       }
 
        list_add(&vxlan->next, &vn->vxlan_list);
        return 0;