1 files changed, 229 insertions, 100 deletions

diff --git a/net/rds/connection.c b/net/rds/connection.c
index e3b118cae81d..f5058559bb08 100644
--- a/net/rds/connection.c
+++ b/net/rds/connection.c
@@ -95,14 +95,16 @@ static struct rds_connection *rds_conn_lookup(struct net *net,
  * and receiving over this connection again in the future.  It is up to
  * the transport to have serialized this call with its send and recv.
  */
-static void rds_conn_reset(struct rds_connection *conn)
+static void rds_conn_path_reset(struct rds_conn_path *cp)
 {
+	struct rds_connection *conn = cp->cp_conn;
+
 	rdsdebug("connection %pI4 to %pI4 reset\n",
 	  &conn->c_laddr, &conn->c_faddr);
 
 	rds_stats_inc(s_conn_reset);
-	rds_send_reset(conn);
-	conn->c_flags = 0;
+	rds_send_path_reset(cp);
+	cp->cp_flags = 0;
 
 	/* Do not clear next_rx_seq here, else we cannot distinguish
 	 * retransmitted packets from new packets, and will hand all
@@ -110,6 +112,32 @@ static void rds_conn_reset(struct rds_connection *conn)
 	 * reliability guarantees of RDS. */
 }
 
+static void __rds_conn_path_init(struct rds_connection *conn,
+				 struct rds_conn_path *cp, bool is_outgoing)
+{
+	spin_lock_init(&cp->cp_lock);
+	cp->cp_next_tx_seq = 1;
+	init_waitqueue_head(&cp->cp_waitq);
+	INIT_LIST_HEAD(&cp->cp_send_queue);
+	INIT_LIST_HEAD(&cp->cp_retrans);
+
+	cp->cp_conn = conn;
+	atomic_set(&cp->cp_state, RDS_CONN_DOWN);
+	cp->cp_send_gen = 0;
+	/* cp_outgoing is per-path. So we can only set it here
+	 * for the single-path transports.
+	 */
+	if (!conn->c_trans->t_mp_capable)
+		cp->cp_outgoing = (is_outgoing ? 1 : 0);
+	cp->cp_reconnect_jiffies = 0;
+	INIT_DELAYED_WORK(&cp->cp_send_w, rds_send_worker);
+	INIT_DELAYED_WORK(&cp->cp_recv_w, rds_recv_worker);
+	INIT_DELAYED_WORK(&cp->cp_conn_w, rds_connect_worker);
+	INIT_WORK(&cp->cp_down_w, rds_shutdown_worker);
+	mutex_init(&cp->cp_cm_lock);
+	cp->cp_flags = 0;
+}
+
 /*
  * There is only every one 'conn' for a given pair of addresses in the
  * system at a time.  They contain messages to be retransmitted and so
@@ -127,7 +155,7 @@ static struct rds_connection *__rds_conn_create(struct net *net,
 	struct hlist_head *head = rds_conn_bucket(laddr, faddr);
 	struct rds_transport *loop_trans;
 	unsigned long flags;
-	int ret;
+	int ret, i;
 
 	rcu_read_lock();
 	conn = rds_conn_lookup(net, head, laddr, faddr, trans);
@@ -153,13 +181,8 @@ static struct rds_connection *__rds_conn_create(struct net *net,
 	INIT_HLIST_NODE(&conn->c_hash_node);
 	conn->c_laddr = laddr;
 	conn->c_faddr = faddr;
-	spin_lock_init(&conn->c_lock);
-	conn->c_next_tx_seq = 1;
-	rds_conn_net_set(conn, net);
 
-	init_waitqueue_head(&conn->c_waitq);
-	INIT_LIST_HEAD(&conn->c_send_queue);
-	INIT_LIST_HEAD(&conn->c_retrans);
+	rds_conn_net_set(conn, net);
 
 	ret = rds_cong_get_maps(conn);
 	if (ret) {
@@ -188,6 +211,12 @@ static struct rds_connection *__rds_conn_create(struct net *net,
 
 	conn->c_trans = trans;
 
+	init_waitqueue_head(&conn->c_hs_waitq);
+	for (i = 0; i < RDS_MPATH_WORKERS; i++) {
+		__rds_conn_path_init(conn, &conn->c_path[i],
+				     is_outgoing);
+		conn->c_path[i].cp_index = i;
+	}
 	ret = trans->conn_alloc(conn, gfp);
 	if (ret) {
 		kmem_cache_free(rds_conn_slab, conn);
@@ -195,17 +224,6 @@ static struct rds_connection *__rds_conn_create(struct net *net,
 		goto out;
 	}
 
-	atomic_set(&conn->c_state, RDS_CONN_DOWN);
-	conn->c_send_gen = 0;
-	conn->c_outgoing = (is_outgoing ? 1 : 0);
-	conn->c_reconnect_jiffies = 0;
-	INIT_DELAYED_WORK(&conn->c_send_w, rds_send_worker);
-	INIT_DELAYED_WORK(&conn->c_recv_w, rds_recv_worker);
-	INIT_DELAYED_WORK(&conn->c_conn_w, rds_connect_worker);
-	INIT_WORK(&conn->c_down_w, rds_shutdown_worker);
-	mutex_init(&conn->c_cm_lock);
-	conn->c_flags = 0;
-
 	rdsdebug("allocated conn %p for %pI4 -> %pI4 over %s %s\n",
 	  conn, &laddr, &faddr,
 	  trans->t_name ? trans->t_name : "[unknown]",
@@ -222,7 +240,7 @@ static struct rds_connection *__rds_conn_create(struct net *net,
 	if (parent) {
 		/* Creating passive conn */
 		if (parent->c_passive) {
-			trans->conn_free(conn->c_transport_data);
+			trans->conn_free(conn->c_path[0].cp_transport_data);
 			kmem_cache_free(rds_conn_slab, conn);
 			conn = parent->c_passive;
 		} else {
@@ -236,7 +254,18 @@ static struct rds_connection *__rds_conn_create(struct net *net,
 
 		found = rds_conn_lookup(net, head, laddr, faddr, trans);
 		if (found) {
-			trans->conn_free(conn->c_transport_data);
+			struct rds_conn_path *cp;
+			int i;
+
+			for (i = 0; i < RDS_MPATH_WORKERS; i++) {
+				cp = &conn->c_path[i];
+				/* The ->conn_alloc invocation may have
+				 * allocated resource for all paths, so all
+				 * of them may have to be freed here.
+				 */
+				if (cp->cp_transport_data)
+					trans->conn_free(cp->cp_transport_data);
+			}
 			kmem_cache_free(rds_conn_slab, conn);
 			conn = found;
 		} else {
@@ -267,10 +296,12 @@ struct rds_connection *rds_conn_create_outgoing(struct net *net,
 }
 EXPORT_SYMBOL_GPL(rds_conn_create_outgoing);
 
-void rds_conn_shutdown(struct rds_connection *conn)
+void rds_conn_shutdown(struct rds_conn_path *cp)
 {
+	struct rds_connection *conn = cp->cp_conn;
+
 	/* shut it down unless it's down already */
-	if (!rds_conn_transition(conn, RDS_CONN_DOWN, RDS_CONN_DOWN)) {
+	if (!rds_conn_path_transition(cp, RDS_CONN_DOWN, RDS_CONN_DOWN)) {
 		/*
 		 * Quiesce the connection mgmt handlers before we start tearing
 		 * things down. We don't hold the mutex for the entire
@@ -278,35 +309,38 @@ void rds_conn_shutdown(struct rds_connection *conn)
 		 * deadlocking with the CM handler. Instead, the CM event
 		 * handler is supposed to check for state DISCONNECTING
 		 */
-		mutex_lock(&conn->c_cm_lock);
-		if (!rds_conn_transition(conn, RDS_CONN_UP, RDS_CONN_DISCONNECTING)
-		 && !rds_conn_transition(conn, RDS_CONN_ERROR, RDS_CONN_DISCONNECTING)) {
-			rds_conn_error(conn, "shutdown called in state %d\n",
-					atomic_read(&conn->c_state));
-			mutex_unlock(&conn->c_cm_lock);
+		mutex_lock(&cp->cp_cm_lock);
+		if (!rds_conn_path_transition(cp, RDS_CONN_UP,
+					      RDS_CONN_DISCONNECTING) &&
+		    !rds_conn_path_transition(cp, RDS_CONN_ERROR,
+					      RDS_CONN_DISCONNECTING)) {
+			rds_conn_path_error(cp,
+					    "shutdown called in state %d\n",
+					    atomic_read(&cp->cp_state));
+			mutex_unlock(&cp->cp_cm_lock);
 			return;
 		}
-		mutex_unlock(&conn->c_cm_lock);
+		mutex_unlock(&cp->cp_cm_lock);
 
-		wait_event(conn->c_waitq,
-			   !test_bit(RDS_IN_XMIT, &conn->c_flags));
-		wait_event(conn->c_waitq,
-			   !test_bit(RDS_RECV_REFILL, &conn->c_flags));
+		wait_event(cp->cp_waitq,
+			   !test_bit(RDS_IN_XMIT, &cp->cp_flags));
+		wait_event(cp->cp_waitq,
+			   !test_bit(RDS_RECV_REFILL, &cp->cp_flags));
 
-		conn->c_trans->conn_shutdown(conn);
-		rds_conn_reset(conn);
+		conn->c_trans->conn_path_shutdown(cp);
+		rds_conn_path_reset(cp);
 
-		if (!rds_conn_transition(conn, RDS_CONN_DISCONNECTING, RDS_CONN_DOWN)) {
+		if (!rds_conn_path_transition(cp, RDS_CONN_DISCONNECTING,
+					      RDS_CONN_DOWN)) {
 			/* This can happen - eg when we're in the middle of tearing
 			 * down the connection, and someone unloads the rds module.
 			 * Quite reproduceable with loopback connections.
 			 * Mostly harmless.
 			 */
-			rds_conn_error(conn,
-				"%s: failed to transition to state DOWN, "
-				"current state is %d\n",
-				__func__,
-				atomic_read(&conn->c_state));
+			rds_conn_path_error(cp, "%s: failed to transition "
+					    "to state DOWN, current state "
+					    "is %d\n", __func__,
+					    atomic_read(&cp->cp_state));
 			return;
 		}
 	}
@@ -315,18 +349,47 @@ void rds_conn_shutdown(struct rds_connection *conn)
 	 * The passive side of an IB loopback connection is never added
 	 * to the conn hash, so we never trigger a reconnect on this
 	 * conn - the reconnect is always triggered by the active peer. */
-	cancel_delayed_work_sync(&conn->c_conn_w);
+	cancel_delayed_work_sync(&cp->cp_conn_w);
 	rcu_read_lock();
 	if (!hlist_unhashed(&conn->c_hash_node)) {
 		rcu_read_unlock();
-		if (conn->c_trans->t_type != RDS_TRANS_TCP ||
-		    conn->c_outgoing == 1)
-			rds_queue_reconnect(conn);
+		rds_queue_reconnect(cp);
 	} else {
 		rcu_read_unlock();
 	}
 }
 
+/* destroy a single rds_conn_path. rds_conn_destroy() iterates over
+ * all paths using rds_conn_path_destroy()
+ */
+static void rds_conn_path_destroy(struct rds_conn_path *cp)
+{
+	struct rds_message *rm, *rtmp;
+
+	if (!cp->cp_transport_data)
+		return;
+
+	rds_conn_path_drop(cp);
+	flush_work(&cp->cp_down_w);
+
+	/* make sure lingering queued work won't try to ref the conn */
+	cancel_delayed_work_sync(&cp->cp_send_w);
+	cancel_delayed_work_sync(&cp->cp_recv_w);
+
+	/* tear down queued messages */
+	list_for_each_entry_safe(rm, rtmp,
+				 &cp->cp_send_queue,
+				 m_conn_item) {
+		list_del_init(&rm->m_conn_item);
+		BUG_ON(!list_empty(&rm->m_sock_item));
+		rds_message_put(rm);
+	}
+	if (cp->cp_xmit_rm)
+		rds_message_put(cp->cp_xmit_rm);
+
+	cp->cp_conn->c_trans->conn_free(cp->cp_transport_data);
+}
+
 /*
  * Stop and free a connection.
  *
@@ -336,8 +399,9 @@ void rds_conn_shutdown(struct rds_connection *conn)
  */
 void rds_conn_destroy(struct rds_connection *conn)
 {
-	struct rds_message *rm, *rtmp;
 	unsigned long flags;
+	int i;
+	struct rds_conn_path *cp;
 
 	rdsdebug("freeing conn %p for %pI4 -> "
 		 "%pI4\n", conn, &conn->c_laddr,
@@ -350,25 +414,11 @@ void rds_conn_destroy(struct rds_connection *conn)
 	synchronize_rcu();
 
 	/* shut the connection down */
-	rds_conn_drop(conn);
-	flush_work(&conn->c_down_w);
-
-	/* make sure lingering queued work won't try to ref the conn */
-	cancel_delayed_work_sync(&conn->c_send_w);
-	cancel_delayed_work_sync(&conn->c_recv_w);
-
-	/* tear down queued messages */
-	list_for_each_entry_safe(rm, rtmp,
-				 &conn->c_send_queue,
-				 m_conn_item) {
-		list_del_init(&rm->m_conn_item);
-		BUG_ON(!list_empty(&rm->m_sock_item));
-		rds_message_put(rm);
+	for (i = 0; i < RDS_MPATH_WORKERS; i++) {
+		cp = &conn->c_path[i];
+		rds_conn_path_destroy(cp);
+		BUG_ON(!list_empty(&cp->cp_retrans));
 	}
-	if (conn->c_xmit_rm)
-		rds_message_put(conn->c_xmit_rm);
-
-	conn->c_trans->conn_free(conn->c_transport_data);
 
 	/*
 	 * The congestion maps aren't freed up here.  They're
@@ -377,7 +427,6 @@ void rds_conn_destroy(struct rds_connection *conn)
 	 */
 	rds_cong_remove_conn(conn);
 
-	BUG_ON(!list_empty(&conn->c_retrans));
 	kmem_cache_free(rds_conn_slab, conn);
 
 	spin_lock_irqsave(&rds_conn_lock, flags);
@@ -398,6 +447,7 @@ static void rds_conn_message_info(struct socket *sock, unsigned int len,
 	unsigned int total = 0;
 	unsigned long flags;
 	size_t i;
+	int j;
 
 	len /= sizeof(struct rds_info_message);
 
@@ -406,23 +456,32 @@ static void rds_conn_message_info(struct socket *sock, unsigned int len,
 	for (i = 0, head = rds_conn_hash; i < ARRAY_SIZE(rds_conn_hash);
 	     i++, head++) {
 		hlist_for_each_entry_rcu(conn, head, c_hash_node) {
-			if (want_send)
-				list = &conn->c_send_queue;
-			else
-				list = &conn->c_retrans;
-
-			spin_lock_irqsave(&conn->c_lock, flags);
-
-			/* XXX too lazy to maintain counts.. */
-			list_for_each_entry(rm, list, m_conn_item) {
-				total++;
-				if (total <= len)
-					rds_inc_info_copy(&rm->m_inc, iter,
-							  conn->c_laddr,
-							  conn->c_faddr, 0);
+			struct rds_conn_path *cp;
+
+			for (j = 0; j < RDS_MPATH_WORKERS; j++) {
+				cp = &conn->c_path[j];
+				if (want_send)
+					list = &cp->cp_send_queue;
+				else
+					list = &cp->cp_retrans;
+
+				spin_lock_irqsave(&cp->cp_lock, flags);
+
+				/* XXX too lazy to maintain counts.. */
+				list_for_each_entry(rm, list, m_conn_item) {
+					total++;
+					if (total <= len)
+						rds_inc_info_copy(&rm->m_inc,
+								  iter,
+								  conn->c_laddr,
+								  conn->c_faddr,
+								  0);
+				}
+
+				spin_unlock_irqrestore(&cp->cp_lock, flags);
+				if (!conn->c_trans->t_mp_capable)
+					break;
 			}
-
-			spin_unlock_irqrestore(&conn->c_lock, flags);
 		}
 	}
 	rcu_read_unlock();
@@ -484,27 +543,72 @@ void rds_for_each_conn_info(struct socket *sock, unsigned int len,
 }
 EXPORT_SYMBOL_GPL(rds_for_each_conn_info);
 
-static int rds_conn_info_visitor(struct rds_connection *conn,
-				  void *buffer)
+void rds_walk_conn_path_info(struct socket *sock, unsigned int len,
+			     struct rds_info_iterator *iter,
+			     struct rds_info_lengths *lens,
+			     int (*visitor)(struct rds_conn_path *, void *),
+			     size_t item_len)
+{
+	u64  buffer[(item_len + 7) / 8];
+	struct hlist_head *head;
+	struct rds_connection *conn;
+	size_t i;
+	int j;
+
+	rcu_read_lock();
+
+	lens->nr = 0;
+	lens->each = item_len;
+
+	for (i = 0, head = rds_conn_hash; i < ARRAY_SIZE(rds_conn_hash);
+	     i++, head++) {
+		hlist_for_each_entry_rcu(conn, head, c_hash_node) {
+			struct rds_conn_path *cp;
+
+			for (j = 0; j < RDS_MPATH_WORKERS; j++) {
+				cp = &conn->c_path[j];
+
+				/* XXX no cp_lock usage.. */
+				if (!visitor(cp, buffer))
+					continue;
+				if (!conn->c_trans->t_mp_capable)
+					break;
+			}
+
+			/* We copy as much as we can fit in the buffer,
+			 * but we count all items so that the caller
+			 * can resize the buffer.
+			 */
+			if (len >= item_len) {
+				rds_info_copy(iter, buffer, item_len);
+				len -= item_len;
+			}
+			lens->nr++;
+		}
+	}
+	rcu_read_unlock();
+}
+
+static int rds_conn_info_visitor(struct rds_conn_path *cp, void *buffer)
 {
 	struct rds_info_connection *cinfo = buffer;
 
-	cinfo->next_tx_seq = conn->c_next_tx_seq;
-	cinfo->next_rx_seq = conn->c_next_rx_seq;
-	cinfo->laddr = conn->c_laddr;
-	cinfo->faddr = conn->c_faddr;
-	strncpy(cinfo->transport, conn->c_trans->t_name,
+	cinfo->next_tx_seq = cp->cp_next_tx_seq;
+	cinfo->next_rx_seq = cp->cp_next_rx_seq;
+	cinfo->laddr = cp->cp_conn->c_laddr;
+	cinfo->faddr = cp->cp_conn->c_faddr;
+	strncpy(cinfo->transport, cp->cp_conn->c_trans->t_name,
 		sizeof(cinfo->transport));
 	cinfo->flags = 0;
 
-	rds_conn_info_set(cinfo->flags, test_bit(RDS_IN_XMIT, &conn->c_flags),
+	rds_conn_info_set(cinfo->flags, test_bit(RDS_IN_XMIT, &cp->cp_flags),
 			  SENDING);
 	/* XXX Future: return the state rather than these funky bits */
 	rds_conn_info_set(cinfo->flags,
-			  atomic_read(&conn->c_state) == RDS_CONN_CONNECTING,
+			  atomic_read(&cp->cp_state) == RDS_CONN_CONNECTING,
 			  CONNECTING);
 	rds_conn_info_set(cinfo->flags,
-			  atomic_read(&conn->c_state) == RDS_CONN_UP,
+			  atomic_read(&cp->cp_state) == RDS_CONN_UP,
 			  CONNECTED);
 	return 1;
 }
@@ -513,7 +617,7 @@ static void rds_conn_info(struct socket *sock, unsigned int len,
 			  struct rds_info_iterator *iter,
 			  struct rds_info_lengths *lens)
 {
-	rds_for_each_conn_info(sock, len, iter, lens,
+	rds_walk_conn_path_info(sock, len, iter, lens,
 				rds_conn_info_visitor,
 				sizeof(struct rds_info_connection));
 }
@@ -553,10 +657,17 @@ void rds_conn_exit(void)
 /*
  * Force a disconnect
  */
+void rds_conn_path_drop(struct rds_conn_path *cp)
+{
+	atomic_set(&cp->cp_state, RDS_CONN_ERROR);
+	queue_work(rds_wq, &cp->cp_down_w);
+}
+EXPORT_SYMBOL_GPL(rds_conn_path_drop);
+
 void rds_conn_drop(struct rds_connection *conn)
 {
-	atomic_set(&conn->c_state, RDS_CONN_ERROR);
-	queue_work(rds_wq, &conn->c_down_w);
+	WARN_ON(conn->c_trans->t_mp_capable);
+	rds_conn_path_drop(&conn->c_path[0]);
 }
 EXPORT_SYMBOL_GPL(rds_conn_drop);
 
@@ -564,11 +675,17 @@ EXPORT_SYMBOL_GPL(rds_conn_drop);
  * If the connection is down, trigger a connect. We may have scheduled a
  * delayed reconnect however - in this case we should not interfere.
  */
+void rds_conn_path_connect_if_down(struct rds_conn_path *cp)
+{
+	if (rds_conn_path_state(cp) == RDS_CONN_DOWN &&
+	    !test_and_set_bit(RDS_RECONNECT_PENDING, &cp->cp_flags))
+		queue_delayed_work(rds_wq, &cp->cp_conn_w, 0);
+}
+
 void rds_conn_connect_if_down(struct rds_connection *conn)
 {
-	if (rds_conn_state(conn) == RDS_CONN_DOWN &&
-	    !test_and_set_bit(RDS_RECONNECT_PENDING, &conn->c_flags))
-		queue_delayed_work(rds_wq, &conn->c_conn_w, 0);
+	WARN_ON(conn->c_trans->t_mp_capable);
+	rds_conn_path_connect_if_down(&conn->c_path[0]);
 }
 EXPORT_SYMBOL_GPL(rds_conn_connect_if_down);
 
@@ -586,3 +703,15 @@ __rds_conn_error(struct rds_connection *conn, const char *fmt, ...)
 
 	rds_conn_drop(conn);
 }
+
+void
+__rds_conn_path_error(struct rds_conn_path *cp, const char *fmt, ...)
+{
+	va_list ap;
+
+	va_start(ap, fmt);
+	vprintk(fmt, ap);
+	va_end(ap);
+
+	rds_conn_path_drop(cp);
+}