Merge tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso...
[deliverable/linux.git] / net / tipc / name_table.c
index df3da2924fc7e3d47dfcceb2cf26b123f86fea33..c8df0223371a7b86f971093fee1ac1ba47bffb26 100644 (file)
@@ -92,6 +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;
@@ -101,10 +102,11 @@ struct name_seq {
        struct hlist_node ns_list;
        struct list_head subscriptions;
        spinlock_t lock;
+       struct rcu_head rcu;
 };
 
 struct name_table *tipc_nametbl;
-DEFINE_RWLOCK(tipc_nametbl_lock);
+DEFINE_SPINLOCK(tipc_nametbl_lock);
 
 static int hash(int x)
 {
@@ -131,9 +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->nodesub_list);
        return publ;
 }
 
@@ -168,22 +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
  *
@@ -465,7 +453,7 @@ static struct name_seq *nametbl_find_seq(u32 type)
        struct name_seq *ns;
 
        seq_head = &tipc_nametbl->seq_hlist[hash(type)];
-       hlist_for_each_entry(ns, seq_head, ns_list) {
+       hlist_for_each_entry_rcu(ns, seq_head, ns_list) {
                if (ns->type == type)
                        return ns;
        }
@@ -476,6 +464,7 @@ 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);
 
@@ -492,8 +481,11 @@ struct publication *tipc_nametbl_insert_publ(u32 type, u32 lower, u32 upper,
        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,
@@ -505,8 +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;
 }
 
@@ -535,14 +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 */
@@ -592,7 +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;
 }
@@ -618,13 +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++) {
@@ -642,10 +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;
 }
 
@@ -658,13 +656,14 @@ struct publication *tipc_nametbl_publish(u32 type, u32 lower, u32 upper,
        struct publication *publ;
        struct sk_buff *buf = NULL;
 
+       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)) {
@@ -673,7 +672,7 @@ struct publication *tipc_nametbl_publish(u32 type, u32 lower, u32 upper,
                /* 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);
@@ -686,27 +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)) {
                tipc_nametbl->local_publ_count--;
-               buf = tipc_named_withdraw(publ);
+               skb = tipc_named_withdraw(publ);
                /* Any pending external events? */
                tipc_named_process_backlog();
-               write_unlock_bh(&tipc_nametbl_lock);
                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;
 }
 
@@ -719,7 +719,7 @@ void tipc_nametbl_subscribe(struct tipc_subscription *s)
        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,
@@ -732,7 +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);
 }
 
 /**
@@ -742,18 +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
  */
@@ -876,7 +881,7 @@ static int nametbl_list(char *buf, int len, u32 depth_info,
                upbound = ~0;
                for (i = 0; i < TIPC_NAMETBL_SIZE; i++) {
                        seq_head = &tipc_nametbl->seq_hlist[i];
-                       hlist_for_each_entry(seq, seq_head, ns_list) {
+                       hlist_for_each_entry_rcu(seq, seq_head, ns_list) {
                                ret += nameseq_list(seq, buf + ret, len - ret,
                                                   depth, seq->type,
                                                   lowbound, upbound, i);
@@ -892,7 +897,7 @@ static int nametbl_list(char *buf, int len, u32 depth_info,
                ret += nametbl_header(buf + ret, len - ret, depth);
                i = hash(type);
                seq_head = &tipc_nametbl->seq_hlist[i];
-               hlist_for_each_entry(seq, seq_head, ns_list) {
+               hlist_for_each_entry_rcu(seq, seq_head, ns_list) {
                        if (seq->type == type) {
                                ret += nameseq_list(seq, buf + ret, len - ret,
                                                   depth, type,
@@ -924,11 +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);
@@ -964,17 +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)
@@ -982,22 +989,22 @@ 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(&tipc_nametbl->seq_hlist[i]))
                        continue;
                seq_head = &tipc_nametbl->seq_hlist[i];
-               hlist_for_each_entry_safe(seq, safe, seq_head, ns_list) {
+               hlist_for_each_entry_rcu(seq, seq_head, ns_list) {
                        tipc_purge_publications(seq);
                }
        }
-       write_unlock_bh(&tipc_nametbl_lock);
+       spin_unlock_bh(&tipc_nametbl_lock);
 
+       synchronize_net();
        kfree(tipc_nametbl);
 
 }
@@ -1103,7 +1110,7 @@ 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;
+       struct name_seq *seq = NULL;
        int err;
        int i;
 
@@ -1120,15 +1127,14 @@ static int __tipc_nl_seq_list(struct tipc_nl_msg *msg, u32 *last_type,
                        if (!seq)
                                return -EPIPE;
                } else {
-                       seq = hlist_entry_safe((seq_head)->first,
-                                              struct name_seq, ns_list);
+                       hlist_for_each_entry_rcu(seq, seq_head, ns_list)
+                               break;
                        if (!seq)
                                continue;
                }
 
-               hlist_for_each_entry_from(seq, ns_list) {
+               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);
 
@@ -1160,8 +1166,7 @@ int tipc_nl_name_table_dump(struct sk_buff *skb, struct netlink_callback *cb)
        msg.portid = NETLINK_CB(cb->skb).portid;
        msg.seq = cb->nlh->nlmsg_seq;
 
-       read_lock_bh(&tipc_nametbl_lock);
-
+       rcu_read_lock();
        err = __tipc_nl_seq_list(&msg, &last_type, &last_lower, &last_publ);
        if (!err) {
                done = 1;
@@ -1174,8 +1179,7 @@ int tipc_nl_name_table_dump(struct sk_buff *skb, struct netlink_callback *cb)
                 */
                cb->prev_seq = 1;
        }
-
-       read_unlock_bh(&tipc_nametbl_lock);
+       rcu_read_unlock();
 
        cb->args[0] = last_type;
        cb->args[1] = last_lower;
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