tipc: convert name table read-write lock to RCU
Convert tipc name table read-write lock to RCU. After this change,
a new spin lock is used to protect name table on write side while
RCU is applied on read side.
Signed-off-by: Ying Xue <ying.xue@windriver.com>
Reviewed-by: Erik Hugne <erik.hugne@ericsson.com>
Reviewed-by: Jon Maloy <jon.maloy@ericsson.com>
Tested-by: Erik Hugne <erik.hugne@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/tipc/name_table.c b/net/tipc/name_table.c
index 3c2e0c3..aafa684c 100644
--- a/net/tipc/name_table.c
+++ b/net/tipc/name_table.c
@@ -92,6 +92,7 @@
* @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 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)
{
@@ -166,7 +168,7 @@
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;
}
@@ -451,7 +453,7 @@
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;
}
@@ -498,10 +500,10 @@
spin_lock_bh(&seq->lock);
publ = tipc_nameseq_remove_publ(seq, lower, node, ref, key);
if (!seq->first_free && list_empty(&seq->subscriptions)) {
- hlist_del_init(&seq->ns_list);
- spin_unlock_bh(&seq->lock);
+ hlist_del_init_rcu(&seq->ns_list);
kfree(seq->sseqs);
- kfree(seq);
+ spin_unlock_bh(&seq->lock);
+ kfree_rcu(seq, rcu);
return publ;
}
spin_unlock_bh(&seq->lock);
@@ -533,7 +535,7 @@
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;
@@ -590,7 +592,7 @@
no_match:
spin_unlock_bh(&seq->lock);
not_found:
- read_unlock_bh(&tipc_nametbl_lock);
+ rcu_read_unlock();
*destnode = node;
return ref;
}
@@ -616,7 +618,7 @@
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;
@@ -641,7 +643,7 @@
}
spin_unlock_bh(&seq->lock);
exit:
- read_unlock_bh(&tipc_nametbl_lock);
+ rcu_read_unlock();
return res;
}
@@ -654,11 +656,11 @@
struct publication *publ;
struct sk_buff *buf = NULL;
- write_lock_bh(&tipc_nametbl_lock);
+ 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);
- write_unlock_bh(&tipc_nametbl_lock);
+ spin_unlock_bh(&tipc_nametbl_lock);
return NULL;
}
@@ -670,7 +672,7 @@
/* 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);
@@ -685,7 +687,7 @@
struct publication *publ;
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--;
@@ -693,13 +695,13 @@
/* 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);
}
- write_unlock_bh(&tipc_nametbl_lock);
+ spin_unlock_bh(&tipc_nametbl_lock);
if (skb) {
named_cluster_distribute(skb);
@@ -717,7 +719,7 @@
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,
@@ -730,7 +732,7 @@
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);
}
/**
@@ -740,24 +742,23 @@
{
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);
if (!seq->first_free && list_empty(&seq->subscriptions)) {
- hlist_del_init(&seq->ns_list);
- spin_unlock_bh(&seq->lock);
+ hlist_del_init_rcu(&seq->ns_list);
kfree(seq->sseqs);
- kfree(seq);
+ 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
*/
@@ -880,7 +881,7 @@
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);
@@ -896,7 +897,7 @@
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,
@@ -928,11 +929,11 @@
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);
@@ -974,13 +975,13 @@
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(&seq->ns_list);
+ hlist_del_init_rcu(&seq->ns_list);
+ kfree(seq->sseqs);
spin_lock_bh(&seq->lock);
- kfree(seq->sseqs);
- kfree(seq);
+ kfree_rcu(seq, rcu);
}
void tipc_nametbl_stop(void)
@@ -988,22 +989,22 @@
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);
}
@@ -1109,7 +1110,7 @@
u32 *last_lower, u32 *last_publ)
{
struct hlist_head *seq_head;
- struct name_seq *seq;
+ struct name_seq *seq = NULL;
int err;
int i;
@@ -1126,13 +1127,13 @@
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);
@@ -1165,8 +1166,7 @@
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;
@@ -1179,8 +1179,7 @@
*/
cb->prev_seq = 1;
}
-
- read_unlock_bh(&tipc_nametbl_lock);
+ rcu_read_unlock();
cb->args[0] = last_type;
cb->args[1] = last_lower;