Merge branch 'v6v7' into devel

[linux/fpc-iii.git] / net / tipc / name_table.c

/*
 * net/tipc/name_table.c: TIPC name table code
 *
 * Copyright (c) 2000-2006, Ericsson AB
 * Copyright (c) 2004-2008, Wind River Systems
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the names of the copyright holders nor the names of its
 *    contributors may be used to endorse or promote products derived from
 *    this software without specific prior written permission.
 *
 * Alternatively, this software may be distributed under the terms of the
 * GNU General Public License ("GPL") version 2 as published by the Free
 * Software Foundation.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#include "core.h"
#include "config.h"
#include "name_table.h"
#include "name_distr.h"
#include "subscr.h"
#include "port.h"

static int tipc_nametbl_size = 1024;            /* must be a power of 2 */

/**
 * struct sub_seq - container for all published instances of a name sequence
 * @lower: name sequence lower bound
 * @upper: name sequence upper bound
 * @node_list: circular list of publications made by own node
 * @cluster_list: circular list of publications made by own cluster
 * @zone_list: circular list of publications made by own zone
 * @node_list_size: number of entries in "node_list"
 * @cluster_list_size: number of entries in "cluster_list"
 * @zone_list_size: number of entries in "zone_list"
 *
 * Note: The zone list always contains at least one entry, since all
 *       publications of the associated name sequence belong to it.
 *       (The cluster and node lists may be empty.)
 */

struct sub_seq {
        u32 lower;
        u32 upper;
        struct publication *node_list;
        struct publication *cluster_list;
        struct publication *zone_list;
        u32 node_list_size;
        u32 cluster_list_size;
        u32 zone_list_size;
};

/**
 * struct name_seq - container for all published instances of a name type
 * @type: 32 bit 'type' value for name sequence
 * @sseq: pointer to dynamically-sized array of sub-sequences of this 'type';
 *        sub-sequences are sorted in ascending order
 * @alloc: number of sub-sequences currently in array
 * @first_free: array index of first unused sub-sequence entry
 * @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
 */

struct name_seq {
        u32 type;
        struct sub_seq *sseqs;
        u32 alloc;
        u32 first_free;
        struct hlist_node ns_list;
        struct list_head subscriptions;
        spinlock_t lock;
};

/**
 * 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;
static atomic_t rsv_publ_ok = ATOMIC_INIT(0);
DEFINE_RWLOCK(tipc_nametbl_lock);


static int hash(int x)
{
        return x & (tipc_nametbl_size - 1);
}

/**
 * publ_create - create a publication structure
 */

static struct publication *publ_create(u32 type, u32 lower, u32 upper,
                                       u32 scope, u32 node, u32 port_ref,
                                       u32 key)
{
        struct publication *publ = kzalloc(sizeof(*publ), GFP_ATOMIC);
        if (publ == NULL) {
                warn("Publication creation failure, no memory\n");
                return NULL;
        }

        publ->type = type;
        publ->lower = lower;
        publ->upper = upper;
        publ->scope = scope;
        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;
}

/**
 * tipc_subseq_alloc - allocate a specified number of sub-sequence structures
 */

static struct sub_seq *tipc_subseq_alloc(u32 cnt)
{
        struct sub_seq *sseq = kcalloc(cnt, sizeof(struct sub_seq), GFP_ATOMIC);
        return sseq;
}

/**
 * tipc_nameseq_create - create a name sequence structure for the specified 'type'
 *
 * Allocates a single sub-sequence structure and sets it to all 0's.
 */

static struct name_seq *tipc_nameseq_create(u32 type, struct hlist_head *seq_head)
{
        struct name_seq *nseq = kzalloc(sizeof(*nseq), GFP_ATOMIC);
        struct sub_seq *sseq = tipc_subseq_alloc(1);

        if (!nseq || !sseq) {
                warn("Name sequence creation failed, no memory\n");
                kfree(nseq);
                kfree(sseq);
                return NULL;
        }

        spin_lock_init(&nseq->lock);
        nseq->type = type;
        nseq->sseqs = sseq;
        nseq->alloc = 1;
        INIT_HLIST_NODE(&nseq->ns_list);
        INIT_LIST_HEAD(&nseq->subscriptions);
        hlist_add_head(&nseq->ns_list, seq_head);
        return nseq;
}

/**
 * nameseq_find_subseq - find sub-sequence (if any) matching a name instance
 *
 * Very time-critical, so binary searches through sub-sequence array.
 */

static struct sub_seq *nameseq_find_subseq(struct name_seq *nseq,
                                           u32 instance)
{
        struct sub_seq *sseqs = nseq->sseqs;
        int low = 0;
        int high = nseq->first_free - 1;
        int mid;

        while (low <= high) {
                mid = (low + high) / 2;
                if (instance < sseqs[mid].lower)
                        high = mid - 1;
                else if (instance > sseqs[mid].upper)
                        low = mid + 1;
                else
                        return &sseqs[mid];
        }
        return NULL;
}

/**
 * nameseq_locate_subseq - determine position of name instance in sub-sequence
 *
 * Returns index in sub-sequence array of the entry that contains the specified
 * instance value; if no entry contains that value, returns the position
 * where a new entry for it would be inserted in the array.
 *
 * Note: Similar to binary search code for locating a sub-sequence.
 */

static u32 nameseq_locate_subseq(struct name_seq *nseq, u32 instance)
{
        struct sub_seq *sseqs = nseq->sseqs;
        int low = 0;
        int high = nseq->first_free - 1;
        int mid;

        while (low <= high) {
                mid = (low + high) / 2;
                if (instance < sseqs[mid].lower)
                        high = mid - 1;
                else if (instance > sseqs[mid].upper)
                        low = mid + 1;
                else
                        return mid;
        }
        return low;
}

/**
 * tipc_nameseq_insert_publ -
 */

static struct publication *tipc_nameseq_insert_publ(struct name_seq *nseq,
                                                    u32 type, u32 lower, u32 upper,
                                                    u32 scope, u32 node, u32 port, u32 key)
{
        struct subscription *s;
        struct subscription *st;
        struct publication *publ;
        struct sub_seq *sseq;
        int created_subseq = 0;

        sseq = nameseq_find_subseq(nseq, lower);
        if (sseq) {

                /* Lower end overlaps existing entry => need an exact match */

                if ((sseq->lower != lower) || (sseq->upper != upper)) {
                        warn("Cannot publish {%u,%u,%u}, overlap error\n",
                             type, lower, upper);
                        return NULL;
                }
        } else {
                u32 inspos;
                struct sub_seq *freesseq;

                /* Find where lower end should be inserted */

                inspos = nameseq_locate_subseq(nseq, lower);

                /* Fail if upper end overlaps into an existing entry */

                if ((inspos < nseq->first_free) &&
                    (upper >= nseq->sseqs[inspos].lower)) {
                        warn("Cannot publish {%u,%u,%u}, overlap error\n",
                             type, lower, upper);
                        return NULL;
                }

                /* Ensure there is space for new sub-sequence */

                if (nseq->first_free == nseq->alloc) {
                        struct sub_seq *sseqs = tipc_subseq_alloc(nseq->alloc * 2);

                        if (!sseqs) {
                                warn("Cannot publish {%u,%u,%u}, no memory\n",
                                     type, lower, upper);
                                return NULL;
                        }
                        memcpy(sseqs, nseq->sseqs,
                               nseq->alloc * sizeof(struct sub_seq));
                        kfree(nseq->sseqs);
                        nseq->sseqs = sseqs;
                        nseq->alloc *= 2;
                }

                /* Insert new sub-sequence */

                sseq = &nseq->sseqs[inspos];
                freesseq = &nseq->sseqs[nseq->first_free];
                memmove(sseq + 1, sseq, (freesseq - sseq) * sizeof(*sseq));
                memset(sseq, 0, sizeof(*sseq));
                nseq->first_free++;
                sseq->lower = lower;
                sseq->upper = upper;
                created_subseq = 1;
        }

        /* Insert a publication: */

        publ = publ_create(type, lower, upper, scope, node, port, key);
        if (!publ)
                return NULL;

        sseq->zone_list_size++;
        if (!sseq->zone_list)
                sseq->zone_list = publ->zone_list_next = publ;
        else {
                publ->zone_list_next = sseq->zone_list->zone_list_next;
                sseq->zone_list->zone_list_next = publ;
        }

        if (in_own_cluster(node)) {
                sseq->cluster_list_size++;
                if (!sseq->cluster_list)
                        sseq->cluster_list = publ->cluster_list_next = publ;
                else {
                        publ->cluster_list_next =
                        sseq->cluster_list->cluster_list_next;
                        sseq->cluster_list->cluster_list_next = publ;
                }
        }

        if (node == tipc_own_addr) {
                sseq->node_list_size++;
                if (!sseq->node_list)
                        sseq->node_list = publ->node_list_next = publ;
                else {
                        publ->node_list_next = sseq->node_list->node_list_next;
                        sseq->node_list->node_list_next = publ;
                }
        }

        /*
         * Any subscriptions waiting for notification?
         */
        list_for_each_entry_safe(s, st, &nseq->subscriptions, nameseq_list) {
                tipc_subscr_report_overlap(s,
                                           publ->lower,
                                           publ->upper,
                                           TIPC_PUBLISHED,
                                           publ->ref,
                                           publ->node,
                                           created_subseq);
        }
        return publ;
}

/**
 * tipc_nameseq_remove_publ -
 *
 * NOTE: There may be cases where TIPC is asked to remove a publication
 * that is not in the name table.  For example, if another node issues a
 * publication for a name sequence that overlaps an existing name sequence
 * the publication will not be recorded, which means the publication won't
 * be found when the name sequence is later withdrawn by that node.
 * A failed withdraw request simply returns a failure indication and lets the
 * caller issue any error or warning messages associated with such a problem.
 */

static struct publication *tipc_nameseq_remove_publ(struct name_seq *nseq, u32 inst,
                                                    u32 node, u32 ref, u32 key)
{
        struct publication *publ;
        struct publication *curr;
        struct publication *prev;
        struct sub_seq *sseq = nameseq_find_subseq(nseq, inst);
        struct sub_seq *free;
        struct subscription *s, *st;
        int removed_subseq = 0;

        if (!sseq)
                return NULL;

        /* Remove publication from zone scope list */

        prev = sseq->zone_list;
        publ = sseq->zone_list->zone_list_next;
        while ((publ->key != key) || (publ->ref != ref) ||
               (publ->node && (publ->node != node))) {
                prev = publ;
                publ = publ->zone_list_next;
                if (prev == sseq->zone_list) {

                        /* Prevent endless loop if publication not found */

                        return NULL;
                }
        }
        if (publ != sseq->zone_list)
                prev->zone_list_next = publ->zone_list_next;
        else if (publ->zone_list_next != publ) {
                prev->zone_list_next = publ->zone_list_next;
                sseq->zone_list = publ->zone_list_next;
        } else {
                sseq->zone_list = NULL;
        }
        sseq->zone_list_size--;

        /* Remove publication from cluster scope list, if present */

        if (in_own_cluster(node)) {
                prev = sseq->cluster_list;
                curr = sseq->cluster_list->cluster_list_next;
                while (curr != publ) {
                        prev = curr;
                        curr = curr->cluster_list_next;
                        if (prev == sseq->cluster_list) {

                                /* Prevent endless loop for malformed list */

                                err("Unable to de-list cluster publication\n"
                                    "{%u%u}, node=0x%x, ref=%u, key=%u)\n",
                                    publ->type, publ->lower, publ->node,
                                    publ->ref, publ->key);
                                goto end_cluster;
                        }
                }
                if (publ != sseq->cluster_list)
                        prev->cluster_list_next = publ->cluster_list_next;
                else if (publ->cluster_list_next != publ) {
                        prev->cluster_list_next = publ->cluster_list_next;
                        sseq->cluster_list = publ->cluster_list_next;
                } else {
                        sseq->cluster_list = NULL;
                }
                sseq->cluster_list_size--;
        }
end_cluster:

        /* Remove publication from node scope list, if present */

        if (node == tipc_own_addr) {
                prev = sseq->node_list;
                curr = sseq->node_list->node_list_next;
                while (curr != publ) {
                        prev = curr;
                        curr = curr->node_list_next;
                        if (prev == sseq->node_list) {

                                /* Prevent endless loop for malformed list */

                                err("Unable to de-list node publication\n"
                                    "{%u%u}, node=0x%x, ref=%u, key=%u)\n",
                                    publ->type, publ->lower, publ->node,
                                    publ->ref, publ->key);
                                goto end_node;
                        }
                }
                if (publ != sseq->node_list)
                        prev->node_list_next = publ->node_list_next;
                else if (publ->node_list_next != publ) {
                        prev->node_list_next = publ->node_list_next;
                        sseq->node_list = publ->node_list_next;
                } else {
                        sseq->node_list = NULL;
                }
                sseq->node_list_size--;
        }
end_node:

        /* Contract subseq list if no more publications for that subseq */

        if (!sseq->zone_list) {
                free = &nseq->sseqs[nseq->first_free--];
                memmove(sseq, sseq + 1, (free - (sseq + 1)) * sizeof(*sseq));
                removed_subseq = 1;
        }

        /* Notify any waiting subscriptions */

        list_for_each_entry_safe(s, st, &nseq->subscriptions, nameseq_list) {
                tipc_subscr_report_overlap(s,
                                           publ->lower,
                                           publ->upper,
                                           TIPC_WITHDRAWN,
                                           publ->ref,
                                           publ->node,
                                           removed_subseq);
        }

        return publ;
}

/**
 * tipc_nameseq_subscribe: attach a subscription, and issue
 * the prescribed number of events if there is any sub-
 * sequence overlapping with the requested sequence
 */

static void tipc_nameseq_subscribe(struct name_seq *nseq, struct subscription *s)
{
        struct sub_seq *sseq = nseq->sseqs;

        list_add(&s->nameseq_list, &nseq->subscriptions);

        if (!sseq)
                return;

        while (sseq != &nseq->sseqs[nseq->first_free]) {
                struct publication *zl = sseq->zone_list;
                if (zl && tipc_subscr_overlap(s, sseq->lower, sseq->upper)) {
                        struct publication *crs = zl;
                        int must_report = 1;

                        do {
                                tipc_subscr_report_overlap(s,
                                                           sseq->lower,
                                                           sseq->upper,
                                                           TIPC_PUBLISHED,
                                                           crs->ref,
                                                           crs->node,
                                                           must_report);
                                must_report = 0;
                                crs = crs->zone_list_next;
                        } while (crs != zl);
                }
                sseq++;
        }
}

static struct name_seq *nametbl_find_seq(u32 type)
{
        struct hlist_head *seq_head;
        struct hlist_node *seq_node;
        struct name_seq *ns;

        seq_head = &table.types[hash(type)];
        hlist_for_each_entry(ns, seq_node, seq_head, ns_list) {
                if (ns->type == type)
                        return ns;
        }

        return NULL;
};

struct publication *tipc_nametbl_insert_publ(u32 type, u32 lower, u32 upper,
                                             u32 scope, u32 node, u32 port, u32 key)
{
        struct name_seq *seq = nametbl_find_seq(type);

        if (lower > upper) {
                warn("Failed to publish illegal {%u,%u,%u}\n",
                     type, lower, upper);
                return NULL;
        }

        if (!seq)
                seq = tipc_nameseq_create(type, &table.types[hash(type)]);
        if (!seq)
                return NULL;

        return tipc_nameseq_insert_publ(seq, type, lower, upper,
                                        scope, node, port, key);
}

struct publication *tipc_nametbl_remove_publ(u32 type, u32 lower,
                                             u32 node, u32 ref, u32 key)
{
        struct publication *publ;
        struct name_seq *seq = nametbl_find_seq(type);

        if (!seq)
                return NULL;

        publ = tipc_nameseq_remove_publ(seq, lower, node, ref, key);

        if (!seq->first_free && list_empty(&seq->subscriptions)) {
                hlist_del_init(&seq->ns_list);
                kfree(seq->sseqs);
                kfree(seq);
        }
        return publ;
}

/*
 * tipc_nametbl_translate - translate name to port id
 *
 * Note: on entry 'destnode' is the search domain used during translation;
 *       on exit it passes back the node address of the matching port (if any)
 */

u32 tipc_nametbl_translate(u32 type, u32 instance, u32 *destnode)
{
        struct sub_seq *sseq;
        struct publication *publ = NULL;
        struct name_seq *seq;
        u32 ref;

        if (!tipc_in_scope(*destnode, tipc_own_addr))
                return 0;

        read_lock_bh(&tipc_nametbl_lock);
        seq = nametbl_find_seq(type);
        if (unlikely(!seq))
                goto not_found;
        sseq = nameseq_find_subseq(seq, instance);
        if (unlikely(!sseq))
                goto not_found;
        spin_lock_bh(&seq->lock);

        /* Closest-First Algorithm: */
        if (likely(!*destnode)) {
                publ = sseq->node_list;
                if (publ) {
                        sseq->node_list = publ->node_list_next;
found:
                        ref = publ->ref;
                        *destnode = publ->node;
                        spin_unlock_bh(&seq->lock);
                        read_unlock_bh(&tipc_nametbl_lock);
                        return ref;
                }
                publ = sseq->cluster_list;
                if (publ) {
                        sseq->cluster_list = publ->cluster_list_next;
                        goto found;
                }
                publ = sseq->zone_list;
                if (publ) {
                        sseq->zone_list = publ->zone_list_next;
                        goto found;
                }
        }

        /* Round-Robin Algorithm: */
        else if (*destnode == tipc_own_addr) {
                publ = sseq->node_list;
                if (publ) {
                        sseq->node_list = publ->node_list_next;
                        goto found;
                }
        } else if (in_own_cluster(*destnode)) {
                publ = sseq->cluster_list;
                if (publ) {
                        sseq->cluster_list = publ->cluster_list_next;
                        goto found;
                }
        } else {
                publ = sseq->zone_list;
                if (publ) {
                        sseq->zone_list = publ->zone_list_next;
                        goto found;
                }
        }
        spin_unlock_bh(&seq->lock);
not_found:
        read_unlock_bh(&tipc_nametbl_lock);
        return 0;
}

/**
 * tipc_nametbl_mc_translate - find multicast destinations
 *
 * Creates list of all local ports that overlap the given multicast address;
 * also determines if any off-node ports overlap.
 *
 * Note: Publications with a scope narrower than 'limit' are ignored.
 * (i.e. local node-scope publications mustn't receive messages arriving
 * from another node, even if the multcast link brought it here)
 *
 * Returns non-zero if any off-node ports overlap
 */

int tipc_nametbl_mc_translate(u32 type, u32 lower, u32 upper, u32 limit,
                              struct port_list *dports)
{
        struct name_seq *seq;
        struct sub_seq *sseq;
        struct sub_seq *sseq_stop;
        int res = 0;

        read_lock_bh(&tipc_nametbl_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++) {
                struct publication *publ;

                if (sseq->lower > upper)
                        break;

                publ = sseq->node_list;
                if (publ) {
                        do {
                                if (publ->scope <= limit)
                                        tipc_port_list_add(dports, publ->ref);
                                publ = publ->node_list_next;
                        } while (publ != sseq->node_list);
                }

                if (sseq->cluster_list_size != sseq->node_list_size)
                        res = 1;
        }

        spin_unlock_bh(&seq->lock);
exit:
        read_unlock_bh(&tipc_nametbl_lock);
        return res;
}

/**
 * tipc_nametbl_publish_rsv - publish port name using a reserved name type
 */

int tipc_nametbl_publish_rsv(u32 ref, unsigned int scope,
                        struct tipc_name_seq const *seq)
{
        int res;

        atomic_inc(&rsv_publ_ok);
        res = tipc_publish(ref, scope, seq);
        atomic_dec(&rsv_publ_ok);
        return res;
}

/**
 * tipc_nametbl_publish - add name publication to network name tables
 */

struct publication *tipc_nametbl_publish(u32 type, u32 lower, u32 upper,
                                    u32 scope, u32 port_ref, u32 key)
{
        struct publication *publ;

        if (table.local_publ_count >= tipc_max_publications) {
                warn("Publication failed, local publication limit reached (%u)\n",
                     tipc_max_publications);
                return NULL;
        }
        if ((type < TIPC_RESERVED_TYPES) && !atomic_read(&rsv_publ_ok)) {
                warn("Publication failed, reserved name {%u,%u,%u}\n",
                     type, lower, upper);
                return NULL;
        }

        write_lock_bh(&tipc_nametbl_lock);
        table.local_publ_count++;
        publ = tipc_nametbl_insert_publ(type, lower, upper, scope,
                                   tipc_own_addr, port_ref, key);
        if (publ && (scope != TIPC_NODE_SCOPE))
                tipc_named_publish(publ);
        write_unlock_bh(&tipc_nametbl_lock);
        return publ;
}

/**
 * tipc_nametbl_withdraw - withdraw name publication from network name tables
 */

int tipc_nametbl_withdraw(u32 type, u32 lower, u32 ref, u32 key)
{
        struct publication *publ;

        write_lock_bh(&tipc_nametbl_lock);
        publ = tipc_nametbl_remove_publ(type, lower, tipc_own_addr, ref, key);
        if (likely(publ)) {
                table.local_publ_count--;
                if (publ->scope != TIPC_NODE_SCOPE)
                        tipc_named_withdraw(publ);
                write_unlock_bh(&tipc_nametbl_lock);
                list_del_init(&publ->pport_list);
                kfree(publ);
                return 1;
        }
        write_unlock_bh(&tipc_nametbl_lock);
        err("Unable to remove local publication\n"
            "(type=%u, lower=%u, ref=%u, key=%u)\n",
            type, lower, ref, key);
        return 0;
}

/**
 * tipc_nametbl_subscribe - add a subscription object to the name table
 */

void tipc_nametbl_subscribe(struct subscription *s)
{
        u32 type = s->seq.type;
        struct name_seq *seq;

        write_lock_bh(&tipc_nametbl_lock);
        seq = nametbl_find_seq(type);
        if (!seq)
                seq = tipc_nameseq_create(type, &table.types[hash(type)]);
        if (seq) {
                spin_lock_bh(&seq->lock);
                tipc_nameseq_subscribe(seq, s);
                spin_unlock_bh(&seq->lock);
        } else {
                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);
}

/**
 * tipc_nametbl_unsubscribe - remove a subscription object from name table
 */

void tipc_nametbl_unsubscribe(struct subscription *s)
{
        struct name_seq *seq;

        write_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);
                if ((seq->first_free == 0) && list_empty(&seq->subscriptions)) {
                        hlist_del_init(&seq->ns_list);
                        kfree(seq->sseqs);
                        kfree(seq);
                }
        }
        write_unlock_bh(&tipc_nametbl_lock);
}


/**
 * subseq_list: print specified sub-sequence contents into the given buffer
 */

static void subseq_list(struct sub_seq *sseq, struct print_buf *buf, u32 depth,
                        u32 index)
{
        char portIdStr[27];
        const char *scope_str[] = {"", " zone", " cluster", " node"};
        struct publication *publ = sseq->zone_list;

        tipc_printf(buf, "%-10u %-10u ", sseq->lower, sseq->upper);

        if (depth == 2 || !publ) {
                tipc_printf(buf, "\n");
                return;
        }

        do {
                sprintf(portIdStr, "<%u.%u.%u:%u>",
                         tipc_zone(publ->node), tipc_cluster(publ->node),
                         tipc_node(publ->node), publ->ref);
                tipc_printf(buf, "%-26s ", portIdStr);
                if (depth > 3) {
                        tipc_printf(buf, "%-10u %s", publ->key,
                                    scope_str[publ->scope]);
                }

                publ = publ->zone_list_next;
                if (publ == sseq->zone_list)
                        break;

                tipc_printf(buf, "\n%33s", " ");
        } while (1);

        tipc_printf(buf, "\n");
}

/**
 * nameseq_list: print specified name sequence contents into the given buffer
 */

static void nameseq_list(struct name_seq *seq, struct print_buf *buf, u32 depth,
                         u32 type, u32 lowbound, u32 upbound, u32 index)
{
        struct sub_seq *sseq;
        char typearea[11];

        if (seq->first_free == 0)
                return;

        sprintf(typearea, "%-10u", seq->type);

        if (depth == 1) {
                tipc_printf(buf, "%s\n", typearea);
                return;
        }

        for (sseq = seq->sseqs; sseq != &seq->sseqs[seq->first_free]; sseq++) {
                if ((lowbound <= sseq->upper) && (upbound >= sseq->lower)) {
                        tipc_printf(buf, "%s ", typearea);
                        spin_lock_bh(&seq->lock);
                        subseq_list(sseq, buf, depth, index);
                        spin_unlock_bh(&seq->lock);
                        sprintf(typearea, "%10s", " ");
                }
        }
}

/**
 * nametbl_header - print name table header into the given buffer
 */

static void nametbl_header(struct print_buf *buf, u32 depth)
{
        const char *header[] = {
                "Type       ",
                "Lower      Upper      ",
                "Port Identity              ",
                "Publication Scope"
        };

        int i;

        if (depth > 4)
                depth = 4;
        for (i = 0; i < depth; i++)
                tipc_printf(buf, header[i]);
        tipc_printf(buf, "\n");
}

/**
 * nametbl_list - print specified name table contents into the given buffer
 */

static void nametbl_list(struct print_buf *buf, u32 depth_info,
                         u32 type, u32 lowbound, u32 upbound)
{
        struct hlist_head *seq_head;
        struct hlist_node *seq_node;
        struct name_seq *seq;
        int all_types;
        u32 depth;
        u32 i;

        all_types = (depth_info & TIPC_NTQ_ALLTYPES);
        depth = (depth_info & ~TIPC_NTQ_ALLTYPES);

        if (depth == 0)
                return;

        if (all_types) {
                /* display all entries in name table to specified depth */
                nametbl_header(buf, depth);
                lowbound = 0;
                upbound = ~0;
                for (i = 0; i < tipc_nametbl_size; i++) {
                        seq_head = &table.types[i];
                        hlist_for_each_entry(seq, seq_node, seq_head, ns_list) {
                                nameseq_list(seq, buf, depth, seq->type,
                                             lowbound, upbound, i);
                        }
                }
        } else {
                /* display only the sequence that matches the specified type */
                if (upbound < lowbound) {
                        tipc_printf(buf, "invalid name sequence specified\n");
                        return;
                }
                nametbl_header(buf, depth);
                i = hash(type);
                seq_head = &table.types[i];
                hlist_for_each_entry(seq, seq_node, seq_head, ns_list) {
                        if (seq->type == type) {
                                nameseq_list(seq, buf, depth, type,
                                             lowbound, upbound, i);
                                break;
                        }
                }
        }
}

#define MAX_NAME_TBL_QUERY 32768

struct sk_buff *tipc_nametbl_get(const void *req_tlv_area, int req_tlv_space)
{
        struct sk_buff *buf;
        struct tipc_name_table_query *argv;
        struct tlv_desc *rep_tlv;
        struct print_buf b;
        int str_len;

        if (!TLV_CHECK(req_tlv_area, req_tlv_space, TIPC_TLV_NAME_TBL_QUERY))
                return tipc_cfg_reply_error_string(TIPC_CFG_TLV_ERROR);

        buf = tipc_cfg_reply_alloc(TLV_SPACE(MAX_NAME_TBL_QUERY));
        if (!buf)
                return NULL;

        rep_tlv = (struct tlv_desc *)buf->data;
        tipc_printbuf_init(&b, TLV_DATA(rep_tlv), MAX_NAME_TBL_QUERY);
        argv = (struct tipc_name_table_query *)TLV_DATA(req_tlv_area);
        read_lock_bh(&tipc_nametbl_lock);
        nametbl_list(&b, ntohl(argv->depth), ntohl(argv->type),
                     ntohl(argv->lowbound), ntohl(argv->upbound));
        read_unlock_bh(&tipc_nametbl_lock);
        str_len = tipc_printbuf_validate(&b);

        skb_put(buf, TLV_SPACE(str_len));
        TLV_SET(rep_tlv, TIPC_TLV_ULTRA_STRING, NULL, str_len);

        return buf;
}

int tipc_nametbl_init(void)
{
        table.types = kcalloc(tipc_nametbl_size, sizeof(struct hlist_head),
                              GFP_ATOMIC);
        if (!table.types)
                return -ENOMEM;

        table.local_publ_count = 0;
        return 0;
}

void tipc_nametbl_stop(void)
{
        u32 i;

        if (!table.types)
                return;

        /* Verify name table is empty, then release it */

        write_lock_bh(&tipc_nametbl_lock);
        for (i = 0; i < tipc_nametbl_size; i++) {
                if (!hlist_empty(&table.types[i]))
                        err("tipc_nametbl_stop(): hash chain %u is non-null\n", i);
        }
        kfree(table.types);
        table.types = NULL;
        write_unlock_bh(&tipc_nametbl_lock);
}