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Commit 97ede29e authored by Ying Xue's avatar Ying Xue Committed by David S. Miller
Browse files

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: default avatarYing Xue <ying.xue@windriver.com>
Reviewed-by: default avatarErik Hugne <erik.hugne@ericsson.com>
Reviewed-by: default avatarJon Maloy <jon.maloy@ericsson.com>
Tested-by: default avatarErik Hugne <erik.hugne@ericsson.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 834caafa

include/linux/rculist.h

+9 −0
Original line number Diff line number Diff line
@@ -542,6 +542,15 @@ static inline void hlist_add_behind_rcu(struct hlist_node *n, 
	     pos = hlist_entry_safe(rcu_dereference_bh((pos)->member.next),\

			typeof(*(pos)), member))



/**

 * hlist_for_each_entry_from_rcu - iterate over a hlist continuing from current point

 * @pos:	the type * to use as a loop cursor.

 * @member:	the name of the hlist_node within the struct.

 */

#define hlist_for_each_entry_from_rcu(pos, member)			\

	for (; pos;							\

	     pos = hlist_entry_safe(rcu_dereference((pos)->member.next),\

			typeof(*(pos)), member))



#endif	/* __KERNEL__ */

#endif

net/tipc/name_distr.c

+14 −14
Original line number Diff line number Diff line
@@ -113,7 +113,7 @@ struct sk_buff *tipc_named_publish(struct publication *publ) 
	struct sk_buff *buf;

	struct distr_item *item;



	list_add_tail(&publ->local_list,

	list_add_tail_rcu(&publ->local_list,

			  &tipc_nametbl->publ_list[publ->scope]);



	if (publ->scope == TIPC_NODE_SCOPE)
@@ -208,12 +208,12 @@ void tipc_named_node_up(u32 dnode) 


	__skb_queue_head_init(&head);



	read_lock_bh(&tipc_nametbl_lock);

	rcu_read_lock();

	named_distribute(&head, dnode,

			 &tipc_nametbl->publ_list[TIPC_CLUSTER_SCOPE]);

	named_distribute(&head, dnode,

			 &tipc_nametbl->publ_list[TIPC_ZONE_SCOPE]);

	read_unlock_bh(&tipc_nametbl_lock);

	rcu_read_unlock();



	tipc_link_xmit(&head, dnode, dnode);

}
@@ -260,12 +260,12 @@ static void tipc_publ_purge(struct publication *publ, u32 addr) 
{

	struct publication *p;



	write_lock_bh(&tipc_nametbl_lock);

	spin_lock_bh(&tipc_nametbl_lock);

	p = tipc_nametbl_remove_publ(publ->type, publ->lower,

				     publ->node, publ->ref, publ->key);

	if (p)

		tipc_publ_unsubscribe(p, addr);

	write_unlock_bh(&tipc_nametbl_lock);

	spin_unlock_bh(&tipc_nametbl_lock);



	if (p != publ) {

		pr_err("Unable to remove publication from failed node\n"
@@ -274,7 +274,7 @@ static void tipc_publ_purge(struct publication *publ, u32 addr) 
		       publ->key);

	}



	kfree(p);

	kfree_rcu(p, rcu);

}



void tipc_publ_notify(struct list_head *nsub_list, u32 addr)
@@ -311,7 +311,7 @@ static bool tipc_update_nametbl(struct distr_item *i, u32 node, u32 dtype) 
						ntohl(i->key));

		if (publ) {

			tipc_publ_unsubscribe(publ, node);

			kfree(publ);

			kfree_rcu(publ, rcu);

			return true;

		}

	} else {
@@ -376,14 +376,14 @@ void tipc_named_rcv(struct sk_buff *buf) 
	u32 count = msg_data_sz(msg) / ITEM_SIZE;

	u32 node = msg_orignode(msg);



	write_lock_bh(&tipc_nametbl_lock);

	spin_lock_bh(&tipc_nametbl_lock);

	while (count--) {

		if (!tipc_update_nametbl(item, node, msg_type(msg)))

			tipc_named_add_backlog(item, msg_type(msg), node);

		item++;

	}

	tipc_named_process_backlog();

	write_unlock_bh(&tipc_nametbl_lock);

	spin_unlock_bh(&tipc_nametbl_lock);

	kfree_skb(buf);

}
@@ -399,12 +399,12 @@ void tipc_named_reinit(void) 
	struct publication *publ;

	int scope;



	write_lock_bh(&tipc_nametbl_lock);

	spin_lock_bh(&tipc_nametbl_lock);



	for (scope = TIPC_ZONE_SCOPE; scope <= TIPC_NODE_SCOPE; scope++)

		list_for_each_entry(publ, &tipc_nametbl->publ_list[scope],

		list_for_each_entry_rcu(publ, &tipc_nametbl->publ_list[scope],

					local_list)

			publ->node = tipc_own_addr;



	write_unlock_bh(&tipc_nametbl_lock);

	spin_unlock_bh(&tipc_nametbl_lock);

}

net/tipc/name_table.c

+43 −44
Original line number Diff line number Diff line
@@ -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;

net/tipc/name_table.h

+3 −1
Original line number Diff line number Diff line
@@ -62,6 +62,7 @@ struct tipc_port_list; 
 * @node_list: adjacent matching name seq publications with >= node scope

 * @cluster_list: adjacent matching name seq publications with >= cluster scope

 * @zone_list: adjacent matching name seq publications with >= zone scope

 * @rcu: RCU callback head used for deferred freeing

 *

 * Note that the node list, cluster list, and zone list are circular lists.

 */
@@ -79,6 +80,7 @@ struct publication { 
	struct list_head node_list;

	struct list_head cluster_list;

	struct list_head zone_list;

	struct rcu_head rcu;

};



/**
@@ -93,7 +95,7 @@ struct name_table { 
	u32 local_publ_count;

};



extern rwlock_t tipc_nametbl_lock;

extern spinlock_t tipc_nametbl_lock;

extern struct name_table *tipc_nametbl;



int tipc_nl_name_table_dump(struct sk_buff *skb, struct netlink_callback *cb);