sctp: apply rhashtable api to sctp procfs

Traversal the transport rhashtable, get the association only once through
the condition assoc->peer.primary_path != transport.
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/sctp/proc.c

@@ -281,63 +281,114 @@ void sctp_eps_proc_exit(struct net *net)
 	remove_proc_entry("eps", net->sctp.proc_net_sctp);
 }
 
+struct sctp_ht_iter {
+	struct seq_net_private p;
+	struct rhashtable_iter hti;
+};
 
-static void *sctp_assocs_seq_start(struct seq_file *seq, loff_t *pos)
+static struct sctp_transport *sctp_transport_get_next(struct seq_file *seq)
 {
-	if (*pos >= sctp_assoc_hashsize)
-		return NULL;
+	struct sctp_ht_iter *iter = seq->private;
+	struct sctp_transport *t;
 
-	if (*pos < 0)
-		*pos = 0;
+	t = rhashtable_walk_next(&iter->hti);
+	for (; t; t = rhashtable_walk_next(&iter->hti)) {
+		if (IS_ERR(t)) {
+			if (PTR_ERR(t) == -EAGAIN)
+				continue;
+			break;
+		}
 
-	if (*pos == 0)
-		seq_printf(seq, " ASSOC     SOCK   STY SST ST HBKT "
-				"ASSOC-ID TX_QUEUE RX_QUEUE UID INODE LPORT "
-				"RPORT LADDRS <-> RADDRS "
-				"HBINT INS OUTS MAXRT T1X T2X RTXC "
-				"wmema wmemq sndbuf rcvbuf\n");
+		if (net_eq(sock_net(t->asoc->base.sk), seq_file_net(seq)) &&
+		    t->asoc->peer.primary_path == t)
+			break;
+	}
 
-	return (void *)pos;
+	return t;
 }
 
-static void sctp_assocs_seq_stop(struct seq_file *seq, void *v)
+static struct sctp_transport *sctp_transport_get_idx(struct seq_file *seq,
+						     loff_t pos)
+{
+	void *obj;
+
+	while (pos && (obj = sctp_transport_get_next(seq)) && !IS_ERR(obj))
+		pos--;
+
+	return obj;
+}
+
+static int sctp_transport_walk_start(struct seq_file *seq)
+{
+	struct sctp_ht_iter *iter = seq->private;
+	int err;
+
+	err = rhashtable_walk_init(&sctp_transport_hashtable, &iter->hti);
+	if (err)
+		return err;
+
+	err = rhashtable_walk_start(&iter->hti);
+
+	return err == -EAGAIN ? 0 : err;
+}
+
+static void sctp_transport_walk_stop(struct seq_file *seq)
+{
+	struct sctp_ht_iter *iter = seq->private;
+
+	rhashtable_walk_stop(&iter->hti);
+	rhashtable_walk_exit(&iter->hti);
+}
+
+static void *sctp_assocs_seq_start(struct seq_file *seq, loff_t *pos)
 {
+	int err = sctp_transport_walk_start(seq);
+
+	if (err)
+		return ERR_PTR(err);
+
+	return *pos ? sctp_transport_get_idx(seq, *pos) : SEQ_START_TOKEN;
 }
 
+static void sctp_assocs_seq_stop(struct seq_file *seq, void *v)
+{
+	sctp_transport_walk_stop(seq);
+}
 
 static void *sctp_assocs_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 {
-	if (++*pos >= sctp_assoc_hashsize)
-		return NULL;
+	++*pos;
 
-	return pos;
+	return sctp_transport_get_next(seq);
 }
 
 /* Display sctp associations (/proc/net/sctp/assocs). */
 static int sctp_assocs_seq_show(struct seq_file *seq, void *v)
 {
-	struct sctp_hashbucket *head;
-	struct sctp_ep_common *epb;
+	struct sctp_transport *transport;
 	struct sctp_association *assoc;
+	struct sctp_ep_common *epb;
 	struct sock *sk;
-	int    hash = *(loff_t *)v;
 
-	if (hash >= sctp_assoc_hashsize)
-		return -ENOMEM;
+	if (v == SEQ_START_TOKEN) {
+		seq_printf(seq, " ASSOC     SOCK   STY SST ST HBKT "
+				"ASSOC-ID TX_QUEUE RX_QUEUE UID INODE LPORT "
+				"RPORT LADDRS <-> RADDRS "
+				"HBINT INS OUTS MAXRT T1X T2X RTXC "
+				"wmema wmemq sndbuf rcvbuf\n");
+		return 0;
+	}
 
-	head = &sctp_assoc_hashtable[hash];
-	local_bh_disable();
-	read_lock(&head->lock);
-	sctp_for_each_hentry(epb, &head->chain) {
-		assoc = sctp_assoc(epb);
+	transport = (struct sctp_transport *)v;
+	assoc = transport->asoc;
+	epb = &assoc->base;
 	sk = epb->sk;
-		if (!net_eq(sock_net(sk), seq_file_net(seq)))
-			continue;
+
 	seq_printf(seq,
 		   "%8pK %8pK %-3d %-3d %-2d %-4d "
 		   "%4d %8d %8d %7u %5lu %-5d %5d ",
 		   assoc, sk, sctp_sk(sk)->type, sk->sk_state,
-			   assoc->state, hash,
+		   assoc->state, 0,
 		   assoc->assoc_id,
 		   assoc->sndbuf_used,
 		   atomic_read(&assoc->rmem_alloc),
@@ -360,9 +411,6 @@ static int sctp_assocs_seq_show(struct seq_file *seq, void *v)
 		sk->sk_sndbuf,
 		sk->sk_rcvbuf);
 	seq_printf(seq, "\n");
-	}
-	read_unlock(&head->lock);
-	local_bh_enable();
 
 	return 0;
 }
@@ -378,7 +426,7 @@ static const struct seq_operations sctp_assoc_ops = {
 static int sctp_assocs_seq_open(struct inode *inode, struct file *file)
 {
 	return seq_open_net(inode, file, &sctp_assoc_ops,
-			    sizeof(struct seq_net_private));
+			    sizeof(struct sctp_ht_iter));
 }
 
 static const struct file_operations sctp_assocs_seq_fops = {
@@ -409,61 +457,49 @@ void sctp_assocs_proc_exit(struct net *net)
 
 static void *sctp_remaddr_seq_start(struct seq_file *seq, loff_t *pos)
 {
-	if (*pos >= sctp_assoc_hashsize)
-		return NULL;
-
-	if (*pos < 0)
-		*pos = 0;
+	int err = sctp_transport_walk_start(seq);
 
-	if (*pos == 0)
-		seq_printf(seq, "ADDR ASSOC_ID HB_ACT RTO MAX_PATH_RTX "
-				"REM_ADDR_RTX START STATE\n");
+	if (err)
+		return ERR_PTR(err);
 
-	return (void *)pos;
+	return *pos ? sctp_transport_get_idx(seq, *pos) : SEQ_START_TOKEN;
 }
 
 static void *sctp_remaddr_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 {
-	if (++*pos >= sctp_assoc_hashsize)
-		return NULL;
+	++*pos;
 
-	return pos;
+	return sctp_transport_get_next(seq);
 }
 
 static void sctp_remaddr_seq_stop(struct seq_file *seq, void *v)
 {
+	sctp_transport_walk_stop(seq);
 }
 
 static int sctp_remaddr_seq_show(struct seq_file *seq, void *v)
 {
-	struct sctp_hashbucket *head;
-	struct sctp_ep_common *epb;
 	struct sctp_association *assoc;
 	struct sctp_transport *tsp;
-	int    hash = *(loff_t *)v;
 
-	if (hash >= sctp_assoc_hashsize)
-		return -ENOMEM;
+	if (v == SEQ_START_TOKEN) {
+		seq_printf(seq, "ADDR ASSOC_ID HB_ACT RTO MAX_PATH_RTX "
+				"REM_ADDR_RTX START STATE\n");
+		return 0;
+	}
+
+	tsp = (struct sctp_transport *)v;
+	assoc = tsp->asoc;
 
-	head = &sctp_assoc_hashtable[hash];
-	local_bh_disable();
-	read_lock(&head->lock);
-	rcu_read_lock();
-	sctp_for_each_hentry(epb, &head->chain) {
-		if (!net_eq(sock_net(epb->sk), seq_file_net(seq)))
-			continue;
-		assoc = sctp_assoc(epb);
 	list_for_each_entry_rcu(tsp, &assoc->peer.transport_addr_list,
 				transports) {
 		if (tsp->dead)
 			continue;
-
 		/*
 		 * The remote address (ADDR)
 		 */
 		tsp->af_specific->seq_dump_addr(seq, &tsp->ipaddr);
 		seq_printf(seq, " ");
-
 		/*
 		 * The association ID (ASSOC_ID)
 		 */
@@ -507,14 +543,8 @@ static int sctp_remaddr_seq_show(struct seq_file *seq, void *v)
 
 		seq_printf(seq, "\n");
 	}
-	}
-
-	rcu_read_unlock();
-	read_unlock(&head->lock);
-	local_bh_enable();
 
 	return 0;
-
 }
 
 static const struct seq_operations sctp_remaddr_ops = {
@@ -533,7 +563,7 @@ void sctp_remaddr_proc_exit(struct net *net)
 static int sctp_remaddr_seq_open(struct inode *inode, struct file *file)
 {
 	return seq_open_net(inode, file, &sctp_remaddr_ops,
-			    sizeof(struct seq_net_private));
+			    sizeof(struct sctp_ht_iter));
 }
 
 static const struct file_operations sctp_remaddr_seq_fops = {