1 files changed, 244 insertions, 280 deletions

diff --git a/net/netlink/genetlink.c b/net/netlink/genetlink.c
index 0c741cec4d0d..7dbc4f732c75 100644
--- a/net/netlink/genetlink.c
+++ b/net/netlink/genetlink.c
@@ -65,12 +65,24 @@ static struct list_head family_ht[GENL_FAM_TAB_SIZE];
  * To avoid an allocation at boot of just one unsigned long,
  * declare it global instead.
  * Bit 0 is marked as already used since group 0 is invalid.
+ * Bit 1 is marked as already used since the drop-monitor code
+ * abuses the API and thinks it can statically use group 1.
+ * That group will typically conflict with other groups that
+ * any proper users use.
+ * Bit 16 is marked as used since it's used for generic netlink
+ * and the code no longer marks pre-reserved IDs as used.
+ * Bit 17 is marked as already used since the VFS quota code
+ * also abused this API and relied on family == group ID, we
+ * cater to that by giving it a static family and group ID.
  */
-static unsigned long mc_group_start = 0x1;
+static unsigned long mc_group_start = 0x3 | BIT(GENL_ID_CTRL) |
+                                      BIT(GENL_ID_VFS_DQUOT);
 static unsigned long *mc_groups = &mc_group_start;
 static unsigned long mc_groups_longs = 1;
 
-static int genl_ctrl_event(int event, void *data);
+static int genl_ctrl_event(int event, struct genl_family *family,
+                           const struct genl_multicast_group *grp,
+                           int grp_id);
 
 static inline unsigned int genl_family_hash(unsigned int id)
 {
@@ -106,13 +118,13 @@ static struct genl_family *genl_family_find_byname(char *name)
         return NULL;
 }
 
-static struct genl_ops *genl_get_cmd(u8 cmd, struct genl_family *family)
+static const struct genl_ops *genl_get_cmd(u8 cmd, struct genl_family *family)
 {
-        struct genl_ops *ops;
+        int i;
 
-        list_for_each_entry(ops, &family->ops_list, ops_list)
-                if (ops->cmd == cmd)
-                        return ops;
+        for (i = 0; i < family->n_ops; i++)
+                if (family->ops[i].cmd == cmd)
+                        return &family->ops[i];
 
         return NULL;
 }
@@ -126,7 +138,8 @@ static u16 genl_generate_id(void)
         int i;
 
         for (i = 0; i <= GENL_MAX_ID - GENL_MIN_ID; i++) {
-                if (!genl_family_find_byid(id_gen_idx))
+                if (id_gen_idx != GENL_ID_VFS_DQUOT &&
+                    !genl_family_find_byid(id_gen_idx))
                         return id_gen_idx;
                 if (++id_gen_idx > GENL_MAX_ID)
                         id_gen_idx = GENL_MIN_ID;
@@ -135,62 +148,110 @@ static u16 genl_generate_id(void)
         return 0;
 }
 
-static struct genl_multicast_group notify_grp;
-
-/**
- * genl_register_mc_group - register a multicast group
- *
- * Registers the specified multicast group and notifies userspace
- * about the new group.
- *
- * Returns 0 on success or a negative error code.
- *
- * @family: The generic netlink family the group shall be registered for.
- * @grp: The group to register, must have a name.
- */
-int genl_register_mc_group(struct genl_family *family,
-                           struct genl_multicast_group *grp)
+static int genl_allocate_reserve_groups(int n_groups, int *first_id)
 {
-        int id;
         unsigned long *new_groups;
-        int err = 0;
+        int start = 0;
+        int i;
+        int id;
+        bool fits;
+
+        do {
+                if (start == 0)
+                        id = find_first_zero_bit(mc_groups,
+                                                 mc_groups_longs *
+                                                 BITS_PER_LONG);
+                else
+                        id = find_next_zero_bit(mc_groups,
+                                                mc_groups_longs * BITS_PER_LONG,
+                                                start);
+
+                fits = true;
+                for (i = id;
+                     i < min_t(int, id + n_groups,
+                               mc_groups_longs * BITS_PER_LONG);
+                     i++) {
+                        if (test_bit(i, mc_groups)) {
+                                start = i;
+                                fits = false;
+                                break;
+                        }
+                }
 
-        BUG_ON(grp->name[0] == '\0');
-        BUG_ON(memchr(grp->name, '\0', GENL_NAMSIZ) == NULL);
+                if (id >= mc_groups_longs * BITS_PER_LONG) {
+                        unsigned long new_longs = mc_groups_longs +
+                                                  BITS_TO_LONGS(n_groups);
+                        size_t nlen = new_longs * sizeof(unsigned long);
+
+                        if (mc_groups == &mc_group_start) {
+                                new_groups = kzalloc(nlen, GFP_KERNEL);
+                                if (!new_groups)
+                                        return -ENOMEM;
+                                mc_groups = new_groups;
+                                *mc_groups = mc_group_start;
+                        } else {
+                                new_groups = krealloc(mc_groups, nlen,
+                                                      GFP_KERNEL);
+                                if (!new_groups)
+                                        return -ENOMEM;
+                                mc_groups = new_groups;
+                                for (i = 0; i < BITS_TO_LONGS(n_groups); i++)
+                                        mc_groups[mc_groups_longs + i] = 0;
+                        }
+                        mc_groups_longs = new_longs;
+                }
+        } while (!fits);
 
-        genl_lock_all();
+        for (i = id; i < id + n_groups; i++)
+                set_bit(i, mc_groups);
+        *first_id = id;
+        return 0;
+}
 
-        /* special-case our own group */
-        if (grp == &notify_grp)
-                id = GENL_ID_CTRL;
-        else
-                id = find_first_zero_bit(mc_groups,
-                                         mc_groups_longs * BITS_PER_LONG);
+static struct genl_family genl_ctrl;
 
+static int genl_validate_assign_mc_groups(struct genl_family *family)
+{
+        int first_id;
+        int n_groups = family->n_mcgrps;
+        int err, i;
+        bool groups_allocated = false;
 
-        if (id >= mc_groups_longs * BITS_PER_LONG) {
-                size_t nlen = (mc_groups_longs + 1) * sizeof(unsigned long);
+        if (!n_groups)
+                return 0;
 
-                if (mc_groups == &mc_group_start) {
-                        new_groups = kzalloc(nlen, GFP_KERNEL);
-                        if (!new_groups) {
-                                err = -ENOMEM;
-                                goto out;
-                        }
-                        mc_groups = new_groups;
-                        *mc_groups = mc_group_start;
-                } else {
-                        new_groups = krealloc(mc_groups, nlen, GFP_KERNEL);
-                        if (!new_groups) {
-                                err = -ENOMEM;
-                                goto out;
-                        }
-                        mc_groups = new_groups;
-                        mc_groups[mc_groups_longs] = 0;
-                }
-                mc_groups_longs++;
+        for (i = 0; i < n_groups; i++) {
+                const struct genl_multicast_group *grp = &family->mcgrps[i];
+
+                if (WARN_ON(grp->name[0] == '\0'))
+                        return -EINVAL;
+                if (WARN_ON(memchr(grp->name, '\0', GENL_NAMSIZ) == NULL))
+                        return -EINVAL;
+        }
+
+        /* special-case our own group and hacks */
+        if (family == &genl_ctrl) {
+                first_id = GENL_ID_CTRL;
+                BUG_ON(n_groups != 1);
+        } else if (strcmp(family->name, "NET_DM") == 0) {
+                first_id = 1;
+                BUG_ON(n_groups != 1);
+        } else if (strcmp(family->name, "VFS_DQUOT") == 0) {
+                first_id = GENL_ID_VFS_DQUOT;
+                BUG_ON(n_groups != 1);
+        } else {
+                groups_allocated = true;
+                err = genl_allocate_reserve_groups(n_groups, &first_id);
+                if (err)
+                        return err;
         }
 
+        family->mcgrp_offset = first_id;
+
+        /* if still initializing, can't and don't need to to realloc bitmaps */
+        if (!init_net.genl_sock)
+                return 0;
+
         if (family->netnsok) {
                 struct net *net;
 
@@ -206,9 +267,7 @@ int genl_register_mc_group(struct genl_family *family,
                                  * number of _possible_ groups has been
                                  * increased on some sockets which is ok.
                                  */
-                                rcu_read_unlock();
-                                netlink_table_ungrab();
-                                goto out;
+                                break;
                         }
                 }
                 rcu_read_unlock();
@@ -216,152 +275,67 @@ int genl_register_mc_group(struct genl_family *family,
         } else {
                 err = netlink_change_ngroups(init_net.genl_sock,
                                              mc_groups_longs * BITS_PER_LONG);
-                if (err)
-                        goto out;
         }
 
-        grp->id = id;
-        set_bit(id, mc_groups);
-        list_add_tail(&grp->list, &family->mcast_groups);
-        grp->family = family;
+        if (groups_allocated && err) {
+                for (i = 0; i < family->n_mcgrps; i++)
+                        clear_bit(family->mcgrp_offset + i, mc_groups);
+        }
 
-        genl_ctrl_event(CTRL_CMD_NEWMCAST_GRP, grp);
- out:
-        genl_unlock_all();
         return err;
 }
-EXPORT_SYMBOL(genl_register_mc_group);
 
-static void __genl_unregister_mc_group(struct genl_family *family,
-                                       struct genl_multicast_group *grp)
+static void genl_unregister_mc_groups(struct genl_family *family)
 {
         struct net *net;
-        BUG_ON(grp->family != family);
+        int i;
 
         netlink_table_grab();
         rcu_read_lock();
-        for_each_net_rcu(net)
-                __netlink_clear_multicast_users(net->genl_sock, grp->id);
+        for_each_net_rcu(net) {
+                for (i = 0; i < family->n_mcgrps; i++)
+                        __netlink_clear_multicast_users(
+                                net->genl_sock, family->mcgrp_offset + i);
+        }
         rcu_read_unlock();
         netlink_table_ungrab();
 
-        clear_bit(grp->id, mc_groups);
-        list_del(&grp->list);
-        genl_ctrl_event(CTRL_CMD_DELMCAST_GRP, grp);
-        grp->id = 0;
-        grp->family = NULL;
-}
+        for (i = 0; i < family->n_mcgrps; i++) {
+                int grp_id = family->mcgrp_offset + i;
 
-/**
- * genl_unregister_mc_group - unregister a multicast group
- *
- * Unregisters the specified multicast group and notifies userspace
- * about it. All current listeners on the group are removed.
- *
- * Note: It is not necessary to unregister all multicast groups before
- *       unregistering the family, unregistering the family will cause
- *       all assigned multicast groups to be unregistered automatically.
- *
- * @family: Generic netlink family the group belongs to.
- * @grp: The group to unregister, must have been registered successfully
- *       previously.
- */
-void genl_unregister_mc_group(struct genl_family *family,
-                              struct genl_multicast_group *grp)
-{
-        genl_lock_all();
-        __genl_unregister_mc_group(family, grp);
-        genl_unlock_all();
+                if (grp_id != 1)
+                        clear_bit(grp_id, mc_groups);
+                genl_ctrl_event(CTRL_CMD_DELMCAST_GRP, family,
+                                &family->mcgrps[i], grp_id);
+        }
 }
-EXPORT_SYMBOL(genl_unregister_mc_group);
 
-static void genl_unregister_mc_groups(struct genl_family *family)
+static int genl_validate_ops(struct genl_family *family)
 {
-        struct genl_multicast_group *grp, *tmp;
+        const struct genl_ops *ops = family->ops;
+        unsigned int n_ops = family->n_ops;
+        int i, j;
 
-        list_for_each_entry_safe(grp, tmp, &family->mcast_groups, list)
-                __genl_unregister_mc_group(family, grp);
-}
-
-/**
- * genl_register_ops - register generic netlink operations
- * @family: generic netlink family
- * @ops: operations to be registered
- *
- * Registers the specified operations and assigns them to the specified
- * family. Either a doit or dumpit callback must be specified or the
- * operation will fail. Only one operation structure per command
- * identifier may be registered.
- *
- * See include/net/genetlink.h for more documenation on the operations
- * structure.
- *
- * Returns 0 on success or a negative error code.
- */
-int genl_register_ops(struct genl_family *family, struct genl_ops *ops)
-{
-        int err = -EINVAL;
+        if (WARN_ON(n_ops && !ops))
+                return -EINVAL;
 
-        if (ops->dumpit == NULL && ops->doit == NULL)
-                goto errout;
+        if (!n_ops)
+                return 0;
 
-        if (genl_get_cmd(ops->cmd, family)) {
-                err = -EEXIST;
-                goto errout;
+        for (i = 0; i < n_ops; i++) {
+                if (ops[i].dumpit == NULL && ops[i].doit == NULL)
+                        return -EINVAL;
+                for (j = i + 1; j < n_ops; j++)
+                        if (ops[i].cmd == ops[j].cmd)
+                                return -EINVAL;
         }
 
-        if (ops->dumpit)
-                ops->flags |= GENL_CMD_CAP_DUMP;
-        if (ops->doit)
-                ops->flags |= GENL_CMD_CAP_DO;
-        if (ops->policy)
-                ops->flags |= GENL_CMD_CAP_HASPOL;
+        /* family is not registered yet, so no locking needed */
+        family->ops = ops;
+        family->n_ops = n_ops;
 
-        genl_lock_all();
-        list_add_tail(&ops->ops_list, &family->ops_list);
-        genl_unlock_all();
-
-        genl_ctrl_event(CTRL_CMD_NEWOPS, ops);
-        err = 0;
-errout:
-        return err;
-}
-EXPORT_SYMBOL(genl_register_ops);
-
-/**
- * genl_unregister_ops - unregister generic netlink operations
- * @family: generic netlink family
- * @ops: operations to be unregistered
- *
- * Unregisters the specified operations and unassigns them from the
- * specified family. The operation blocks until the current message
- * processing has finished and doesn't start again until the
- * unregister process has finished.
- *
- * Note: It is not necessary to unregister all operations before
- *       unregistering the family, unregistering the family will cause
- *       all assigned operations to be unregistered automatically.
- *
- * Returns 0 on success or a negative error code.
- */
-int genl_unregister_ops(struct genl_family *family, struct genl_ops *ops)
-{
-        struct genl_ops *rc;
-
-        genl_lock_all();
-        list_for_each_entry(rc, &family->ops_list, ops_list) {
-                if (rc == ops) {
-                        list_del(&ops->ops_list);
-                        genl_unlock_all();
-                        genl_ctrl_event(CTRL_CMD_DELOPS, ops);
-                        return 0;
-                }
-        }
-        genl_unlock_all();
-
-        return -ENOENT;
+        return 0;
 }
-EXPORT_SYMBOL(genl_unregister_ops);
 
 /**
  * __genl_register_family - register a generic netlink family
@@ -372,11 +346,14 @@ EXPORT_SYMBOL(genl_unregister_ops);
  * The family id may equal GENL_ID_GENERATE causing an unique id to
  * be automatically generated and assigned.
  *
+ * The family's ops array must already be assigned, you can use the
+ * genl_register_family_with_ops() helper function.
+ *
  * Return 0 on success or a negative error code.
  */
 int __genl_register_family(struct genl_family *family)
 {
-        int err = -EINVAL;
+        int err = -EINVAL, i;
 
         if (family->id && family->id < GENL_MIN_ID)
                 goto errout;
@@ -384,8 +361,9 @@ int __genl_register_family(struct genl_family *family)
         if (family->id > GENL_MAX_ID)
                 goto errout;
 
-        INIT_LIST_HEAD(&family->ops_list);
-        INIT_LIST_HEAD(&family->mcast_groups);
+        err = genl_validate_ops(family);
+        if (err)
+                return err;
 
         genl_lock_all();
 
@@ -418,10 +396,18 @@ int __genl_register_family(struct genl_family *family)
         } else
                 family->attrbuf = NULL;
 
+        err = genl_validate_assign_mc_groups(family);
+        if (err)
+                goto errout_locked;
+
         list_add_tail(&family->family_list, genl_family_chain(family->id));
         genl_unlock_all();
 
-        genl_ctrl_event(CTRL_CMD_NEWFAMILY, family);
+        /* send all events */
+        genl_ctrl_event(CTRL_CMD_NEWFAMILY, family, NULL, 0);
+        for (i = 0; i < family->n_mcgrps; i++)
+                genl_ctrl_event(CTRL_CMD_NEWMCAST_GRP, family,
+                                &family->mcgrps[i], family->mcgrp_offset + i);
 
         return 0;
 
@@ -433,52 +419,6 @@ errout:
 EXPORT_SYMBOL(__genl_register_family);
 
 /**
- * __genl_register_family_with_ops - register a generic netlink family
- * @family: generic netlink family
- * @ops: operations to be registered
- * @n_ops: number of elements to register
- *
- * Registers the specified family and operations from the specified table.
- * Only one family may be registered with the same family name or identifier.
- *
- * The family id may equal GENL_ID_GENERATE causing an unique id to
- * be automatically generated and assigned.
- *
- * Either a doit or dumpit callback must be specified for every registered
- * operation or the function will fail. Only one operation structure per
- * command identifier may be registered.
- *
- * See include/net/genetlink.h for more documenation on the operations
- * structure.
- *
- * This is equivalent to calling genl_register_family() followed by
- * genl_register_ops() for every operation entry in the table taking
- * care to unregister the family on error path.
- *
- * Return 0 on success or a negative error code.
- */
-int __genl_register_family_with_ops(struct genl_family *family,
-        struct genl_ops *ops, size_t n_ops)
-{
-        int err, i;
-
-        err = __genl_register_family(family);
-        if (err)
-                return err;
-
-        for (i = 0; i < n_ops; ++i, ++ops) {
-                err = genl_register_ops(family, ops);
-                if (err)
-                        goto err_out;
-        }
-        return 0;
-err_out:
-        genl_unregister_family(family);
-        return err;
-}
-EXPORT_SYMBOL(__genl_register_family_with_ops);
-
-/**
  * genl_unregister_family - unregister generic netlink family
  * @family: generic netlink family
  *
@@ -499,11 +439,11 @@ int genl_unregister_family(struct genl_family *family)
                         continue;
 
                 list_del(&rc->family_list);
-                INIT_LIST_HEAD(&family->ops_list);
+                family->n_ops = 0;
                 genl_unlock_all();
 
                 kfree(family->attrbuf);
-                genl_ctrl_event(CTRL_CMD_DELFAMILY, family);
+                genl_ctrl_event(CTRL_CMD_DELFAMILY, family, NULL, 0);
                 return 0;
         }
 
@@ -546,7 +486,8 @@ EXPORT_SYMBOL(genlmsg_put);
 
 static int genl_lock_dumpit(struct sk_buff *skb, struct netlink_callback *cb)
 {
-        struct genl_ops *ops = cb->data;
+        /* our ops are always const - netlink API doesn't propagate that */
+        const struct genl_ops *ops = cb->data;
         int rc;
 
         genl_lock();
@@ -557,7 +498,8 @@ static int genl_lock_dumpit(struct sk_buff *skb, struct netlink_callback *cb)
 
 static int genl_lock_done(struct netlink_callback *cb)
 {
-        struct genl_ops *ops = cb->data;
+        /* our ops are always const - netlink API doesn't propagate that */
+        const struct genl_ops *ops = cb->data;
         int rc = 0;
 
         if (ops->done) {
@@ -572,7 +514,7 @@ static int genl_family_rcv_msg(struct genl_family *family,
                                struct sk_buff *skb,
                                struct nlmsghdr *nlh)
 {
-        struct genl_ops *ops;
+        const struct genl_ops *ops;
         struct net *net = sock_net(skb->sk);
         struct genl_info info;
         struct genlmsghdr *hdr = nlmsg_data(nlh);
@@ -604,7 +546,8 @@ static int genl_family_rcv_msg(struct genl_family *family,
                 if (!family->parallel_ops) {
                         struct netlink_dump_control c = {
                                 .module = family->module,
-                                .data = ops,
+                                /* we have const, but the netlink API doesn't */
+                                .data = (void *)ops,
                                 .dump = genl_lock_dumpit,
                                 .done = genl_lock_done,
                         };
@@ -726,24 +669,32 @@ static int ctrl_fill_info(struct genl_family *family, u32 portid, u32 seq,
             nla_put_u32(skb, CTRL_ATTR_MAXATTR, family->maxattr))
                 goto nla_put_failure;
 
-        if (!list_empty(&family->ops_list)) {
+        if (family->n_ops) {
                 struct nlattr *nla_ops;
-                struct genl_ops *ops;
-                int idx = 1;
+                int i;
 
                 nla_ops = nla_nest_start(skb, CTRL_ATTR_OPS);
                 if (nla_ops == NULL)
                         goto nla_put_failure;
 
-                list_for_each_entry(ops, &family->ops_list, ops_list) {
+                for (i = 0; i < family->n_ops; i++) {
                         struct nlattr *nest;
+                        const struct genl_ops *ops = &family->ops[i];
+                        u32 op_flags = ops->flags;
 
-                        nest = nla_nest_start(skb, idx++);
+                        if (ops->dumpit)
+                                op_flags |= GENL_CMD_CAP_DUMP;
+                        if (ops->doit)
+                                op_flags |= GENL_CMD_CAP_DO;
+                        if (ops->policy)
+                                op_flags |= GENL_CMD_CAP_HASPOL;
+
+                        nest = nla_nest_start(skb, i + 1);
                         if (nest == NULL)
                                 goto nla_put_failure;
 
                         if (nla_put_u32(skb, CTRL_ATTR_OP_ID, ops->cmd) ||
-                            nla_put_u32(skb, CTRL_ATTR_OP_FLAGS, ops->flags))
+                            nla_put_u32(skb, CTRL_ATTR_OP_FLAGS, op_flags))
                                 goto nla_put_failure;
 
                         nla_nest_end(skb, nest);
@@ -752,23 +703,26 @@ static int ctrl_fill_info(struct genl_family *family, u32 portid, u32 seq,
                 nla_nest_end(skb, nla_ops);
         }
 
-        if (!list_empty(&family->mcast_groups)) {
-                struct genl_multicast_group *grp;
+        if (family->n_mcgrps) {
                 struct nlattr *nla_grps;
-                int idx = 1;
+                int i;
 
                 nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS);
                 if (nla_grps == NULL)
                         goto nla_put_failure;
 
-                list_for_each_entry(grp, &family->mcast_groups, list) {
+                for (i = 0; i < family->n_mcgrps; i++) {
                         struct nlattr *nest;
+                        const struct genl_multicast_group *grp;
+
+                        grp = &family->mcgrps[i];
 
-                        nest = nla_nest_start(skb, idx++);
+                        nest = nla_nest_start(skb, i + 1);
                         if (nest == NULL)
                                 goto nla_put_failure;
 
-                        if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID, grp->id) ||
+                        if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID,
+                                        family->mcgrp_offset + i) ||
                             nla_put_string(skb, CTRL_ATTR_MCAST_GRP_NAME,
                                            grp->name))
                                 goto nla_put_failure;
@@ -785,9 +739,10 @@ nla_put_failure:
         return -EMSGSIZE;
 }
 
-static int ctrl_fill_mcgrp_info(struct genl_multicast_group *grp, u32 portid,
-                                u32 seq, u32 flags, struct sk_buff *skb,
-                                u8 cmd)
+static int ctrl_fill_mcgrp_info(struct genl_family *family,
+                                const struct genl_multicast_group *grp,
+                                int grp_id, u32 portid, u32 seq, u32 flags,
+                                struct sk_buff *skb, u8 cmd)
 {
         void *hdr;
         struct nlattr *nla_grps;
@@ -797,8 +752,8 @@ static int ctrl_fill_mcgrp_info(struct genl_multicast_group *grp, u32 portid,
         if (hdr == NULL)
                 return -1;
 
-        if (nla_put_string(skb, CTRL_ATTR_FAMILY_NAME, grp->family->name) ||
-            nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, grp->family->id))
+        if (nla_put_string(skb, CTRL_ATTR_FAMILY_NAME, family->name) ||
+            nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, family->id))
                 goto nla_put_failure;
 
         nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS);
@@ -809,7 +764,7 @@ static int ctrl_fill_mcgrp_info(struct genl_multicast_group *grp, u32 portid,
         if (nest == NULL)
                 goto nla_put_failure;
 
-        if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID, grp->id) ||
+        if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID, grp_id) ||
             nla_put_string(skb, CTRL_ATTR_MCAST_GRP_NAME,
                            grp->name))
                 goto nla_put_failure;
@@ -875,8 +830,10 @@ static struct sk_buff *ctrl_build_family_msg(struct genl_family *family,
         return skb;
 }
 
-static struct sk_buff *ctrl_build_mcgrp_msg(struct genl_multicast_group *grp,
-                                            u32 portid, int seq, u8 cmd)
+static struct sk_buff *
+ctrl_build_mcgrp_msg(struct genl_family *family,
+                     const struct genl_multicast_group *grp,
+                     int grp_id, u32 portid, int seq, u8 cmd)
 {
         struct sk_buff *skb;
         int err;
@@ -885,7 +842,8 @@ static struct sk_buff *ctrl_build_mcgrp_msg(struct genl_multicast_group *grp,
         if (skb == NULL)
                 return ERR_PTR(-ENOBUFS);
 
-        err = ctrl_fill_mcgrp_info(grp, portid, seq, 0, skb, cmd);
+        err = ctrl_fill_mcgrp_info(family, grp, grp_id, portid,
+                                   seq, 0, skb, cmd);
         if (err < 0) {
                 nlmsg_free(skb);
                 return ERR_PTR(err);
@@ -947,11 +905,11 @@ static int ctrl_getfamily(struct sk_buff *skb, struct genl_info *info)
         return genlmsg_reply(msg, info);
 }
 
-static int genl_ctrl_event(int event, void *data)
+static int genl_ctrl_event(int event, struct genl_family *family,
+                           const struct genl_multicast_group *grp,
+                           int grp_id)
 {
         struct sk_buff *msg;
-        struct genl_family *family;
-        struct genl_multicast_group *grp;
 
         /* genl is still initialising */
         if (!init_net.genl_sock)
@@ -960,14 +918,13 @@ static int genl_ctrl_event(int event, void *data)
         switch (event) {
         case CTRL_CMD_NEWFAMILY:
         case CTRL_CMD_DELFAMILY:
-                family = data;
+                WARN_ON(grp);
                 msg = ctrl_build_family_msg(family, 0, 0, event);
                 break;
         case CTRL_CMD_NEWMCAST_GRP:
         case CTRL_CMD_DELMCAST_GRP:
-                grp = data;
-                family = grp->family;
-                msg = ctrl_build_mcgrp_msg(data, 0, 0, event);
+                BUG_ON(!grp);
+                msg = ctrl_build_mcgrp_msg(family, grp, grp_id, 0, 0, event);
                 break;
         default:
                 return -EINVAL;
@@ -977,26 +934,29 @@ static int genl_ctrl_event(int event, void *data)
                 return PTR_ERR(msg);
 
         if (!family->netnsok) {
-                genlmsg_multicast_netns(&init_net, msg, 0,
-                                        GENL_ID_CTRL, GFP_KERNEL);
+                genlmsg_multicast_netns(&genl_ctrl, &init_net, msg, 0,
+                                        0, GFP_KERNEL);
         } else {
                 rcu_read_lock();
-                genlmsg_multicast_allns(msg, 0, GENL_ID_CTRL, GFP_ATOMIC);
+                genlmsg_multicast_allns(&genl_ctrl, msg, 0,
+                                        0, GFP_ATOMIC);
                 rcu_read_unlock();
         }
 
         return 0;
 }
 
-static struct genl_ops genl_ctrl_ops = {
-        .cmd            = CTRL_CMD_GETFAMILY,
-        .doit           = ctrl_getfamily,
-        .dumpit         = ctrl_dumpfamily,
-        .policy         = ctrl_policy,
+static struct genl_ops genl_ctrl_ops[] = {
+        {
+                .cmd            = CTRL_CMD_GETFAMILY,
+                .doit           = ctrl_getfamily,
+                .dumpit         = ctrl_dumpfamily,
+                .policy         = ctrl_policy,
+        },
 };
 
-static struct genl_multicast_group notify_grp = {
-        .name           = "notify",
+static struct genl_multicast_group genl_ctrl_groups[] = {
+        { .name = "notify", },
 };
 
 static int __net_init genl_pernet_init(struct net *net)
@@ -1036,7 +996,8 @@ static int __init genl_init(void)
         for (i = 0; i < GENL_FAM_TAB_SIZE; i++)
                 INIT_LIST_HEAD(&family_ht[i]);
 
-        err = genl_register_family_with_ops(&genl_ctrl, &genl_ctrl_ops, 1);
+        err = genl_register_family_with_ops_groups(&genl_ctrl, genl_ctrl_ops,
+                                                   genl_ctrl_groups);
         if (err < 0)
                 goto problem;
 
@@ -1044,10 +1005,6 @@ static int __init genl_init(void)
         if (err)
                 goto problem;
 
-        err = genl_register_mc_group(&genl_ctrl, &notify_grp);
-        if (err < 0)
-                goto problem;
-
         return 0;
 
 problem:
@@ -1085,14 +1042,18 @@ static int genlmsg_mcast(struct sk_buff *skb, u32 portid, unsigned long group,
         return err;
 }
 
-int genlmsg_multicast_allns(struct sk_buff *skb, u32 portid, unsigned int group,
-                            gfp_t flags)
+int genlmsg_multicast_allns(struct genl_family *family, struct sk_buff *skb,
+                            u32 portid, unsigned int group, gfp_t flags)
 {
+        if (group >= family->n_mcgrps)
+                return -EINVAL;
+        group = family->mcgrp_offset + group;
         return genlmsg_mcast(skb, portid, group, flags);
 }
 EXPORT_SYMBOL(genlmsg_multicast_allns);
 
-void genl_notify(struct sk_buff *skb, struct net *net, u32 portid, u32 group,
+void genl_notify(struct genl_family *family,
+                 struct sk_buff *skb, struct net *net, u32 portid, u32 group,
                  struct nlmsghdr *nlh, gfp_t flags)
 {
         struct sock *sk = net->genl_sock;
@@ -1101,6 +1062,9 @@ void genl_notify(struct sk_buff *skb, struct net *net, u32 portid, u32 group,
         if (nlh)
                 report = nlmsg_report(nlh);
 
+        if (group >= family->n_mcgrps)
+                return;
+        group = family->mcgrp_offset + group;
         nlmsg_notify(sk, skb, portid, group, report, flags);
 }
 EXPORT_SYMBOL(genl_notify);