1 files changed, 287 insertions, 95 deletions

diff --git a/net/tipc/name_table.c b/net/tipc/name_table.c
index 9d7d37d95187..c8df0223371a 100644
--- a/net/tipc/name_table.c
+++ b/net/tipc/name_table.c
@@ -1,8 +1,8 @@
 /*
  * net/tipc/name_table.c: TIPC name table code
  *
- * Copyright (c) 2000-2006, Ericsson AB
- * Copyright (c) 2004-2008, 2010-2011, Wind River Systems
+ * Copyright (c) 2000-2006, 2014, Ericsson AB
+ * Copyright (c) 2004-2008, 2010-2014, Wind River Systems
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -39,10 +39,15 @@
 #include "name_table.h"
 #include "name_distr.h"
 #include "subscr.h"
-#include "port.h"
 
 #define TIPC_NAMETBL_SIZE 1024          /* must be a power of 2 */
 
+static const struct nla_policy
+tipc_nl_name_table_policy[TIPC_NLA_NAME_TABLE_MAX + 1] = {
+        [TIPC_NLA_NAME_TABLE_UNSPEC]    = { .type = NLA_UNSPEC },
+        [TIPC_NLA_NAME_TABLE_PUBL]      = { .type = NLA_NESTED }
+};
+
 /**
  * struct name_info - name sequence publication info
  * @node_list: circular list of publications made by own node
@@ -87,6 +92,7 @@ struct sub_seq {
  * @ns_list: links to adjacent name sequences in hash chain
  * @subscriptions: list of subscriptions for this 'type'
  * @lock: spinlock controlling access to publication lists of all sub-sequences
+ * @rcu: RCU callback head used for deferred freeing
  */
 struct name_seq {
         u32 type;
@@ -96,21 +102,11 @@ struct name_seq {
         struct hlist_node ns_list;
         struct list_head subscriptions;
         spinlock_t lock;
+        struct rcu_head rcu;
 };
 
-/**
- * struct name_table - table containing all existing port name publications
- * @types: pointer to fixed-sized array of name sequence lists,
- *         accessed via hashing on 'type'; name sequence lists are *not* sorted
- * @local_publ_count: number of publications issued by this node
- */
-struct name_table {
-        struct hlist_head *types;
-        u32 local_publ_count;
-};
-
-static struct name_table table;
-DEFINE_RWLOCK(tipc_nametbl_lock);
+struct name_table *tipc_nametbl;
+DEFINE_SPINLOCK(tipc_nametbl_lock);
 
 static int hash(int x)
 {
@@ -137,9 +133,7 @@ static struct publication *publ_create(u32 type, u32 lower, u32 upper,
         publ->node = node;
         publ->ref = port_ref;
         publ->key = key;
-        INIT_LIST_HEAD(&publ->local_list);
         INIT_LIST_HEAD(&publ->pport_list);
-        INIT_LIST_HEAD(&publ->subscr.nodesub_list);
         return publ;
 }
 
@@ -174,22 +168,10 @@ static struct name_seq *tipc_nameseq_create(u32 type, struct hlist_head *seq_hea
         nseq->alloc = 1;
         INIT_HLIST_NODE(&nseq->ns_list);
         INIT_LIST_HEAD(&nseq->subscriptions);
-        hlist_add_head(&nseq->ns_list, seq_head);
+        hlist_add_head_rcu(&nseq->ns_list, seq_head);
         return nseq;
 }
 
-/*
- * nameseq_delete_empty - deletes a name sequence structure if now unused
- */
-static void nameseq_delete_empty(struct name_seq *seq)
-{
-        if (!seq->first_free && list_empty(&seq->subscriptions)) {
-                hlist_del_init(&seq->ns_list);
-                kfree(seq->sseqs);
-                kfree(seq);
-        }
-}
-
 /**
  * nameseq_find_subseq - find sub-sequence (if any) matching a name instance
  *
@@ -262,8 +244,6 @@ static struct publication *tipc_nameseq_insert_publ(struct name_seq *nseq,
 
                 /* Lower end overlaps existing entry => need an exact match */
                 if ((sseq->lower != lower) || (sseq->upper != upper)) {
-                        pr_warn("Cannot publish {%u,%u,%u}, overlap error\n",
-                                type, lower, upper);
                         return NULL;
                 }
 
@@ -285,8 +265,6 @@ static struct publication *tipc_nameseq_insert_publ(struct name_seq *nseq,
                 /* Fail if upper end overlaps into an existing entry */
                 if ((inspos < nseq->first_free) &&
                     (upper >= nseq->sseqs[inspos].lower)) {
-                        pr_warn("Cannot publish {%u,%u,%u}, overlap error\n",
-                                type, lower, upper);
                         return NULL;
                 }
 
@@ -474,8 +452,8 @@ static struct name_seq *nametbl_find_seq(u32 type)
         struct hlist_head *seq_head;
         struct name_seq *ns;
 
-        seq_head = &table.types[hash(type)];
-        hlist_for_each_entry(ns, seq_head, ns_list) {
+        seq_head = &tipc_nametbl->seq_hlist[hash(type)];
+        hlist_for_each_entry_rcu(ns, seq_head, ns_list) {
                 if (ns->type == type)
                         return ns;
         }
@@ -486,7 +464,9 @@ static struct name_seq *nametbl_find_seq(u32 type)
 struct publication *tipc_nametbl_insert_publ(u32 type, u32 lower, u32 upper,
                                              u32 scope, u32 node, u32 port, u32 key)
 {
+        struct publication *publ;
         struct name_seq *seq = nametbl_find_seq(type);
+        int index = hash(type);
 
         if ((scope < TIPC_ZONE_SCOPE) || (scope > TIPC_NODE_SCOPE) ||
             (lower > upper)) {
@@ -496,12 +476,16 @@ struct publication *tipc_nametbl_insert_publ(u32 type, u32 lower, u32 upper,
         }
 
         if (!seq)
-                seq = tipc_nameseq_create(type, &table.types[hash(type)]);
+                seq = tipc_nameseq_create(type,
+                                          &tipc_nametbl->seq_hlist[index]);
         if (!seq)
                 return NULL;
 
-        return tipc_nameseq_insert_publ(seq, type, lower, upper,
+        spin_lock_bh(&seq->lock);
+        publ = tipc_nameseq_insert_publ(seq, type, lower, upper,
                                         scope, node, port, key);
+        spin_unlock_bh(&seq->lock);
+        return publ;
 }
 
 struct publication *tipc_nametbl_remove_publ(u32 type, u32 lower,
@@ -513,8 +497,16 @@ struct publication *tipc_nametbl_remove_publ(u32 type, u32 lower,
         if (!seq)
                 return NULL;
 
+        spin_lock_bh(&seq->lock);
         publ = tipc_nameseq_remove_publ(seq, lower, node, ref, key);
-        nameseq_delete_empty(seq);
+        if (!seq->first_free && list_empty(&seq->subscriptions)) {
+                hlist_del_init_rcu(&seq->ns_list);
+                kfree(seq->sseqs);
+                spin_unlock_bh(&seq->lock);
+                kfree_rcu(seq, rcu);
+                return publ;
+        }
+        spin_unlock_bh(&seq->lock);
         return publ;
 }
 
@@ -543,14 +535,14 @@ u32 tipc_nametbl_translate(u32 type, u32 instance, u32 *destnode)
         if (!tipc_in_scope(*destnode, tipc_own_addr))
                 return 0;
 
-        read_lock_bh(&tipc_nametbl_lock);
+        rcu_read_lock();
         seq = nametbl_find_seq(type);
         if (unlikely(!seq))
                 goto not_found;
+        spin_lock_bh(&seq->lock);
         sseq = nameseq_find_subseq(seq, instance);
         if (unlikely(!sseq))
-                goto not_found;
-        spin_lock_bh(&seq->lock);
+                goto no_match;
         info = sseq->info;
 
         /* Closest-First Algorithm */
@@ -600,7 +592,7 @@ u32 tipc_nametbl_translate(u32 type, u32 instance, u32 *destnode)
 no_match:
         spin_unlock_bh(&seq->lock);
 not_found:
-        read_unlock_bh(&tipc_nametbl_lock);
+        rcu_read_unlock();
         *destnode = node;
         return ref;
 }
@@ -626,13 +618,12 @@ int tipc_nametbl_mc_translate(u32 type, u32 lower, u32 upper, u32 limit,
         struct name_info *info;
         int res = 0;
 
-        read_lock_bh(&tipc_nametbl_lock);
+        rcu_read_lock();
         seq = nametbl_find_seq(type);
         if (!seq)
                 goto exit;
 
         spin_lock_bh(&seq->lock);
-
         sseq = seq->sseqs + nameseq_locate_subseq(seq, lower);
         sseq_stop = seq->sseqs + seq->first_free;
         for (; sseq != sseq_stop; sseq++) {
@@ -650,10 +641,9 @@ int tipc_nametbl_mc_translate(u32 type, u32 lower, u32 upper, u32 limit,
                 if (info->cluster_list_size != info->node_list_size)
                         res = 1;
         }
-
         spin_unlock_bh(&seq->lock);
 exit:
-        read_unlock_bh(&tipc_nametbl_lock);
+        rcu_read_unlock();
         return res;
 }
 
@@ -666,20 +656,23 @@ struct publication *tipc_nametbl_publish(u32 type, u32 lower, u32 upper,
         struct publication *publ;
         struct sk_buff *buf = NULL;
 
-        if (table.local_publ_count >= TIPC_MAX_PUBLICATIONS) {
+        spin_lock_bh(&tipc_nametbl_lock);
+        if (tipc_nametbl->local_publ_count >= TIPC_MAX_PUBLICATIONS) {
                 pr_warn("Publication failed, local publication limit reached (%u)\n",
                         TIPC_MAX_PUBLICATIONS);
+                spin_unlock_bh(&tipc_nametbl_lock);
                 return NULL;
         }
 
-        write_lock_bh(&tipc_nametbl_lock);
         publ = tipc_nametbl_insert_publ(type, lower, upper, scope,
                                    tipc_own_addr, port_ref, key);
         if (likely(publ)) {
-                table.local_publ_count++;
+                tipc_nametbl->local_publ_count++;
                 buf = tipc_named_publish(publ);
+                /* Any pending external events? */
+                tipc_named_process_backlog();
         }
-        write_unlock_bh(&tipc_nametbl_lock);
+        spin_unlock_bh(&tipc_nametbl_lock);
 
         if (buf)
                 named_cluster_distribute(buf);
@@ -692,25 +685,28 @@ struct publication *tipc_nametbl_publish(u32 type, u32 lower, u32 upper,
 int tipc_nametbl_withdraw(u32 type, u32 lower, u32 ref, u32 key)
 {
         struct publication *publ;
-        struct sk_buff *buf;
+        struct sk_buff *skb = NULL;
 
-        write_lock_bh(&tipc_nametbl_lock);
+        spin_lock_bh(&tipc_nametbl_lock);
         publ = tipc_nametbl_remove_publ(type, lower, tipc_own_addr, ref, key);
         if (likely(publ)) {
-                table.local_publ_count--;
-                buf = tipc_named_withdraw(publ);
-                write_unlock_bh(&tipc_nametbl_lock);
+                tipc_nametbl->local_publ_count--;
+                skb = tipc_named_withdraw(publ);
+                /* Any pending external events? */
+                tipc_named_process_backlog();
                 list_del_init(&publ->pport_list);
-                kfree(publ);
+                kfree_rcu(publ, rcu);
+        } else {
+                pr_err("Unable to remove local publication\n"
+                       "(type=%u, lower=%u, ref=%u, key=%u)\n",
+                       type, lower, ref, key);
+        }
+        spin_unlock_bh(&tipc_nametbl_lock);
 
-                if (buf)
-                        named_cluster_distribute(buf);
+        if (skb) {
+                named_cluster_distribute(skb);
                 return 1;
         }
-        write_unlock_bh(&tipc_nametbl_lock);
-        pr_err("Unable to remove local publication\n"
-               "(type=%u, lower=%u, ref=%u, key=%u)\n",
-               type, lower, ref, key);
         return 0;
 }
 
@@ -720,12 +716,14 @@ int tipc_nametbl_withdraw(u32 type, u32 lower, u32 ref, u32 key)
 void tipc_nametbl_subscribe(struct tipc_subscription *s)
 {
         u32 type = s->seq.type;
+        int index = hash(type);
         struct name_seq *seq;
 
-        write_lock_bh(&tipc_nametbl_lock);
+        spin_lock_bh(&tipc_nametbl_lock);
         seq = nametbl_find_seq(type);
         if (!seq)
-                seq = tipc_nameseq_create(type, &table.types[hash(type)]);
+                seq = tipc_nameseq_create(type,
+                                          &tipc_nametbl->seq_hlist[index]);
         if (seq) {
                 spin_lock_bh(&seq->lock);
                 tipc_nameseq_subscribe(seq, s);
@@ -734,7 +732,7 @@ void tipc_nametbl_subscribe(struct tipc_subscription *s)
                 pr_warn("Failed to create subscription for {%u,%u,%u}\n",
                         s->seq.type, s->seq.lower, s->seq.upper);
         }
-        write_unlock_bh(&tipc_nametbl_lock);
+        spin_unlock_bh(&tipc_nametbl_lock);
 }
 
 /**
@@ -744,18 +742,23 @@ void tipc_nametbl_unsubscribe(struct tipc_subscription *s)
 {
         struct name_seq *seq;
 
-        write_lock_bh(&tipc_nametbl_lock);
+        spin_lock_bh(&tipc_nametbl_lock);
         seq = nametbl_find_seq(s->seq.type);
         if (seq != NULL) {
                 spin_lock_bh(&seq->lock);
                 list_del_init(&s->nameseq_list);
-                spin_unlock_bh(&seq->lock);
-                nameseq_delete_empty(seq);
+                if (!seq->first_free && list_empty(&seq->subscriptions)) {
+                        hlist_del_init_rcu(&seq->ns_list);
+                        kfree(seq->sseqs);
+                        spin_unlock_bh(&seq->lock);
+                        kfree_rcu(seq, rcu);
+                } else {
+                        spin_unlock_bh(&seq->lock);
+                }
         }
-        write_unlock_bh(&tipc_nametbl_lock);
+        spin_unlock_bh(&tipc_nametbl_lock);
 }
 
-
 /**
  * subseq_list - print specified sub-sequence contents into the given buffer
  */
@@ -877,8 +880,8 @@ static int nametbl_list(char *buf, int len, u32 depth_info,
                 lowbound = 0;
                 upbound = ~0;
                 for (i = 0; i < TIPC_NAMETBL_SIZE; i++) {
-                        seq_head = &table.types[i];
-                        hlist_for_each_entry(seq, seq_head, ns_list) {
+                        seq_head = &tipc_nametbl->seq_hlist[i];
+                        hlist_for_each_entry_rcu(seq, seq_head, ns_list) {
                                 ret += nameseq_list(seq, buf + ret, len - ret,
                                                    depth, seq->type,
                                                    lowbound, upbound, i);
@@ -893,8 +896,8 @@ static int nametbl_list(char *buf, int len, u32 depth_info,
                 }
                 ret += nametbl_header(buf + ret, len - ret, depth);
                 i = hash(type);
-                seq_head = &table.types[i];
-                hlist_for_each_entry(seq, seq_head, ns_list) {
+                seq_head = &tipc_nametbl->seq_hlist[i];
+                hlist_for_each_entry_rcu(seq, seq_head, ns_list) {
                         if (seq->type == type) {
                                 ret += nameseq_list(seq, buf + ret, len - ret,
                                                    depth, type,
@@ -926,11 +929,11 @@ struct sk_buff *tipc_nametbl_get(const void *req_tlv_area, int req_tlv_space)
         pb = TLV_DATA(rep_tlv);
         pb_len = ULTRA_STRING_MAX_LEN;
         argv = (struct tipc_name_table_query *)TLV_DATA(req_tlv_area);
-        read_lock_bh(&tipc_nametbl_lock);
+        rcu_read_lock();
         str_len = nametbl_list(pb, pb_len, ntohl(argv->depth),
                                ntohl(argv->type),
                                ntohl(argv->lowbound), ntohl(argv->upbound));
-        read_unlock_bh(&tipc_nametbl_lock);
+        rcu_read_unlock();
         str_len += 1;   /* for "\0" */
         skb_put(buf, TLV_SPACE(str_len));
         TLV_SET(rep_tlv, TIPC_TLV_ULTRA_STRING, NULL, str_len);
@@ -940,12 +943,18 @@ struct sk_buff *tipc_nametbl_get(const void *req_tlv_area, int req_tlv_space)
 
 int tipc_nametbl_init(void)
 {
-        table.types = kcalloc(TIPC_NAMETBL_SIZE, sizeof(struct hlist_head),
-                              GFP_ATOMIC);
-        if (!table.types)
+        int i;
+
+        tipc_nametbl = kzalloc(sizeof(*tipc_nametbl), GFP_ATOMIC);
+        if (!tipc_nametbl)
                 return -ENOMEM;
 
-        table.local_publ_count = 0;
+        for (i = 0; i < TIPC_NAMETBL_SIZE; i++)
+                INIT_HLIST_HEAD(&tipc_nametbl->seq_hlist[i]);
+
+        INIT_LIST_HEAD(&tipc_nametbl->publ_list[TIPC_ZONE_SCOPE]);
+        INIT_LIST_HEAD(&tipc_nametbl->publ_list[TIPC_CLUSTER_SCOPE]);
+        INIT_LIST_HEAD(&tipc_nametbl->publ_list[TIPC_NODE_SCOPE]);
         return 0;
 }
 
@@ -960,17 +969,19 @@ static void tipc_purge_publications(struct name_seq *seq)
         struct sub_seq *sseq;
         struct name_info *info;
 
-        if (!seq->sseqs) {
-                nameseq_delete_empty(seq);
-                return;
-        }
+        spin_lock_bh(&seq->lock);
         sseq = seq->sseqs;
         info = sseq->info;
         list_for_each_entry_safe(publ, safe, &info->zone_list, zone_list) {
                 tipc_nametbl_remove_publ(publ->type, publ->lower, publ->node,
                                          publ->ref, publ->key);
-                kfree(publ);
+                kfree_rcu(publ, rcu);
         }
+        hlist_del_init_rcu(&seq->ns_list);
+        kfree(seq->sseqs);
+        spin_unlock_bh(&seq->lock);
+
+        kfree_rcu(seq, rcu);
 }
 
 void tipc_nametbl_stop(void)
@@ -978,21 +989,202 @@ void tipc_nametbl_stop(void)
         u32 i;
         struct name_seq *seq;
         struct hlist_head *seq_head;
-        struct hlist_node *safe;
 
         /* Verify name table is empty and purge any lingering
          * publications, then release the name table
          */
-        write_lock_bh(&tipc_nametbl_lock);
+        spin_lock_bh(&tipc_nametbl_lock);
         for (i = 0; i < TIPC_NAMETBL_SIZE; i++) {
-                if (hlist_empty(&table.types[i]))
+                if (hlist_empty(&tipc_nametbl->seq_hlist[i]))
                         continue;
-                seq_head = &table.types[i];
-                hlist_for_each_entry_safe(seq, safe, seq_head, ns_list) {
+                seq_head = &tipc_nametbl->seq_hlist[i];
+                hlist_for_each_entry_rcu(seq, seq_head, ns_list) {
                         tipc_purge_publications(seq);
                 }
         }
-        kfree(table.types);
-        table.types = NULL;
-        write_unlock_bh(&tipc_nametbl_lock);
+        spin_unlock_bh(&tipc_nametbl_lock);
+
+        synchronize_net();
+        kfree(tipc_nametbl);
+
+}
+
+static int __tipc_nl_add_nametable_publ(struct tipc_nl_msg *msg,
+                                        struct name_seq *seq,
+                                        struct sub_seq *sseq, u32 *last_publ)
+{
+        void *hdr;
+        struct nlattr *attrs;
+        struct nlattr *publ;
+        struct publication *p;
+
+        if (*last_publ) {
+                list_for_each_entry(p, &sseq->info->zone_list, zone_list)
+                        if (p->key == *last_publ)
+                                break;
+                if (p->key != *last_publ)
+                        return -EPIPE;
+        } else {
+                p = list_first_entry(&sseq->info->zone_list, struct publication,
+                                     zone_list);
+        }
+
+        list_for_each_entry_from(p, &sseq->info->zone_list, zone_list) {
+                *last_publ = p->key;
+
+                hdr = genlmsg_put(msg->skb, msg->portid, msg->seq,
+                                  &tipc_genl_v2_family, NLM_F_MULTI,
+                                  TIPC_NL_NAME_TABLE_GET);
+                if (!hdr)
+                        return -EMSGSIZE;
+
+                attrs = nla_nest_start(msg->skb, TIPC_NLA_NAME_TABLE);
+                if (!attrs)
+                        goto msg_full;
+
+                publ = nla_nest_start(msg->skb, TIPC_NLA_NAME_TABLE_PUBL);
+                if (!publ)
+                        goto attr_msg_full;
+
+                if (nla_put_u32(msg->skb, TIPC_NLA_PUBL_TYPE, seq->type))
+                        goto publ_msg_full;
+                if (nla_put_u32(msg->skb, TIPC_NLA_PUBL_LOWER, sseq->lower))
+                        goto publ_msg_full;
+                if (nla_put_u32(msg->skb, TIPC_NLA_PUBL_UPPER, sseq->upper))
+                        goto publ_msg_full;
+                if (nla_put_u32(msg->skb, TIPC_NLA_PUBL_SCOPE, p->scope))
+                        goto publ_msg_full;
+                if (nla_put_u32(msg->skb, TIPC_NLA_PUBL_NODE, p->node))
+                        goto publ_msg_full;
+                if (nla_put_u32(msg->skb, TIPC_NLA_PUBL_REF, p->ref))
+                        goto publ_msg_full;
+                if (nla_put_u32(msg->skb, TIPC_NLA_PUBL_KEY, p->key))
+                        goto publ_msg_full;
+
+                nla_nest_end(msg->skb, publ);
+                nla_nest_end(msg->skb, attrs);
+                genlmsg_end(msg->skb, hdr);
+        }
+        *last_publ = 0;
+
+        return 0;
+
+publ_msg_full:
+        nla_nest_cancel(msg->skb, publ);
+attr_msg_full:
+        nla_nest_cancel(msg->skb, attrs);
+msg_full:
+        genlmsg_cancel(msg->skb, hdr);
+
+        return -EMSGSIZE;
+}
+
+static int __tipc_nl_subseq_list(struct tipc_nl_msg *msg, struct name_seq *seq,
+                                 u32 *last_lower, u32 *last_publ)
+{
+        struct sub_seq *sseq;
+        struct sub_seq *sseq_start;
+        int err;
+
+        if (*last_lower) {
+                sseq_start = nameseq_find_subseq(seq, *last_lower);
+                if (!sseq_start)
+                        return -EPIPE;
+        } else {
+                sseq_start = seq->sseqs;
+        }
+
+        for (sseq = sseq_start; sseq != &seq->sseqs[seq->first_free]; sseq++) {
+                err = __tipc_nl_add_nametable_publ(msg, seq, sseq, last_publ);
+                if (err) {
+                        *last_lower = sseq->lower;
+                        return err;
+                }
+        }
+        *last_lower = 0;
+
+        return 0;
+}
+
+static int __tipc_nl_seq_list(struct tipc_nl_msg *msg, u32 *last_type,
+                              u32 *last_lower, u32 *last_publ)
+{
+        struct hlist_head *seq_head;
+        struct name_seq *seq = NULL;
+        int err;
+        int i;
+
+        if (*last_type)
+                i = hash(*last_type);
+        else
+                i = 0;
+
+        for (; i < TIPC_NAMETBL_SIZE; i++) {
+                seq_head = &tipc_nametbl->seq_hlist[i];
+
+                if (*last_type) {
+                        seq = nametbl_find_seq(*last_type);
+                        if (!seq)
+                                return -EPIPE;
+                } else {
+                        hlist_for_each_entry_rcu(seq, seq_head, ns_list)
+                                break;
+                        if (!seq)
+                                continue;
+                }
+
+                hlist_for_each_entry_from_rcu(seq, ns_list) {
+                        spin_lock_bh(&seq->lock);
+                        err = __tipc_nl_subseq_list(msg, seq, last_lower,
+                                                    last_publ);
+
+                        if (err) {
+                                *last_type = seq->type;
+                                spin_unlock_bh(&seq->lock);
+                                return err;
+                        }
+                        spin_unlock_bh(&seq->lock);
+                }
+                *last_type = 0;
+        }
+        return 0;
+}
+
+int tipc_nl_name_table_dump(struct sk_buff *skb, struct netlink_callback *cb)
+{
+        int err;
+        int done = cb->args[3];
+        u32 last_type = cb->args[0];
+        u32 last_lower = cb->args[1];
+        u32 last_publ = cb->args[2];
+        struct tipc_nl_msg msg;
+
+        if (done)
+                return 0;
+
+        msg.skb = skb;
+        msg.portid = NETLINK_CB(cb->skb).portid;
+        msg.seq = cb->nlh->nlmsg_seq;
+
+        rcu_read_lock();
+        err = __tipc_nl_seq_list(&msg, &last_type, &last_lower, &last_publ);
+        if (!err) {
+                done = 1;
+        } else if (err != -EMSGSIZE) {
+                /* We never set seq or call nl_dump_check_consistent() this
+                 * means that setting prev_seq here will cause the consistence
+                 * check to fail in the netlink callback handler. Resulting in
+                 * the NLMSG_DONE message having the NLM_F_DUMP_INTR flag set if
+                 * we got an error.
+                 */
+                cb->prev_seq = 1;
+        }
+        rcu_read_unlock();
+
+        cb->args[0] = last_type;
+        cb->args[1] = last_lower;
+        cb->args[2] = last_publ;
+        cb->args[3] = done;
+
+        return skb->len;
 }