From 97ede29e80eead50d8bd533cf163401b88c027be Mon Sep 17 00:00:00 2001 From: Ying Xue Date: Tue, 2 Dec 2014 15:00:30 +0800 Subject: 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 Reviewed-by: Erik Hugne Reviewed-by: Jon Maloy Tested-by: Erik Hugne Signed-off-by: David S. Miller --- net/tipc/name_table.c | 87 +++++++++++++++++++++++++-------------------------- 1 file changed, 43 insertions(+), 44 deletions(-) (limited to 'net/tipc/name_table.c') 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 @@ 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) { @@ -166,7 +168,7 @@ 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; } @@ -451,7 +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; } @@ -498,10 +500,10 @@ struct publication *tipc_nametbl_remove_publ(u32 type, u32 lower, 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 @@ 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; @@ -590,7 +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; } @@ -616,7 +618,7 @@ 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; @@ -641,7 +643,7 @@ int tipc_nametbl_mc_translate(u32 type, u32 lower, u32 upper, u32 limit, } spin_unlock_bh(&seq->lock); exit: - read_unlock_bh(&tipc_nametbl_lock); + rcu_read_unlock(); return res; } @@ -654,11 +656,11 @@ struct publication *tipc_nametbl_publish(u32 type, u32 lower, u32 upper, 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 @@ 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); @@ -685,7 +687,7 @@ int tipc_nametbl_withdraw(u32 type, u32 lower, u32 ref, u32 key) 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 @@ int tipc_nametbl_withdraw(u32 type, u32 lower, u32 ref, u32 key) /* 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 @@ 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, @@ -730,7 +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); } /** @@ -740,24 +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); 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 @@ 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); @@ -896,7 +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, @@ -928,11 +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); @@ -974,13 +975,13 @@ static void tipc_purge_publications(struct name_seq *seq) 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 @@ 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); } @@ -1109,7 +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; @@ -1126,13 +1127,13 @@ 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); @@ -1165,8 +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; @@ -1179,8 +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; -- cgit v1.1