RDS: split out connection specific state from rds_connection to rds_conn_path

In preparation for multipath RDS, split the rds_connection
structure into a base structure, and a per-path struct rds_conn_path.
The base structure tracks information and locks common to all
paths. The workqs for send/recv/shutdown etc are tracked per
rds_conn_path. Thus the workq callbacks now work with rds_conn_path.

This commit allows for one rds_conn_path per rds_connection, and will
be extended into multiple conn_paths in  subsequent commits.

Signed-off-by: Sowmini Varadhan <sowmini.varadhan@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 52 insertions, 40 deletions

diff --git a/net/rds/threads.c b/net/rds/threads.c
index 4a323045719b..6d0979b8dc63 100644
--- a/net/rds/threads.c
+++ b/net/rds/threads.c
@@ -71,30 +71,30 @@
 struct workqueue_struct *rds_wq;
 EXPORT_SYMBOL_GPL(rds_wq);
 
-void rds_connect_path_complete(struct rds_connection *conn, int curr)
+void rds_connect_path_complete(struct rds_conn_path *cp, int curr)
 {
-	if (!rds_conn_transition(conn, curr, RDS_CONN_UP)) {
+	if (!rds_conn_path_transition(cp, curr, RDS_CONN_UP)) {
 		printk(KERN_WARNING "%s: Cannot transition to state UP, "
 				"current state is %d\n",
 				__func__,
-				atomic_read(&conn->c_state));
-		rds_conn_drop(conn);
+				atomic_read(&cp->cp_state));
+		rds_conn_path_drop(cp);
 		return;
 	}
 
 	rdsdebug("conn %p for %pI4 to %pI4 complete\n",
-	  conn, &conn->c_laddr, &conn->c_faddr);
+	  cp->cp_conn, &cp->cp_conn->c_laddr, &cp->cp_conn->c_faddr);
 
-	conn->c_reconnect_jiffies = 0;
-	set_bit(0, &conn->c_map_queued);
-	queue_delayed_work(rds_wq, &conn->c_send_w, 0);
-	queue_delayed_work(rds_wq, &conn->c_recv_w, 0);
+	cp->cp_reconnect_jiffies = 0;
+	set_bit(0, &cp->cp_conn->c_map_queued);
+	queue_delayed_work(rds_wq, &cp->cp_send_w, 0);
+	queue_delayed_work(rds_wq, &cp->cp_recv_w, 0);
 }
 EXPORT_SYMBOL_GPL(rds_connect_path_complete);
 
 void rds_connect_complete(struct rds_connection *conn)
 {
-	rds_connect_path_complete(conn, RDS_CONN_CONNECTING);
+	rds_connect_path_complete(&conn->c_path[0], RDS_CONN_CONNECTING);
 }
 EXPORT_SYMBOL_GPL(rds_connect_complete);
 
@@ -116,46 +116,52 @@ EXPORT_SYMBOL_GPL(rds_connect_complete);
  * We should *always* start with a random backoff; otherwise a broken connection
  * will always take several iterations to be re-established.
  */
-void rds_queue_reconnect(struct rds_connection *conn)
+void rds_queue_reconnect(struct rds_conn_path *cp)
 {
 	unsigned long rand;
+	struct rds_connection *conn = cp->cp_conn;
 
 	rdsdebug("conn %p for %pI4 to %pI4 reconnect jiffies %lu\n",
 	  conn, &conn->c_laddr, &conn->c_faddr,
-	  conn->c_reconnect_jiffies);
+	  cp->cp_reconnect_jiffies);
 
-	set_bit(RDS_RECONNECT_PENDING, &conn->c_flags);
-	if (conn->c_reconnect_jiffies == 0) {
-		conn->c_reconnect_jiffies = rds_sysctl_reconnect_min_jiffies;
-		queue_delayed_work(rds_wq, &conn->c_conn_w, 0);
+	set_bit(RDS_RECONNECT_PENDING, &cp->cp_flags);
+	if (cp->cp_reconnect_jiffies == 0) {
+		cp->cp_reconnect_jiffies = rds_sysctl_reconnect_min_jiffies;
+		queue_delayed_work(rds_wq, &cp->cp_conn_w, 0);
 		return;
 	}
 
 	get_random_bytes(&rand, sizeof(rand));
 	rdsdebug("%lu delay %lu ceil conn %p for %pI4 -> %pI4\n",
-		 rand % conn->c_reconnect_jiffies, conn->c_reconnect_jiffies,
+		 rand % cp->cp_reconnect_jiffies, cp->cp_reconnect_jiffies,
 		 conn, &conn->c_laddr, &conn->c_faddr);
-	queue_delayed_work(rds_wq, &conn->c_conn_w,
-			   rand % conn->c_reconnect_jiffies);
+	queue_delayed_work(rds_wq, &cp->cp_conn_w,
+			   rand % cp->cp_reconnect_jiffies);
 
-	conn->c_reconnect_jiffies = min(conn->c_reconnect_jiffies * 2,
+	cp->cp_reconnect_jiffies = min(cp->cp_reconnect_jiffies * 2,
 					rds_sysctl_reconnect_max_jiffies);
 }
 
 void rds_connect_worker(struct work_struct *work)
 {
-	struct rds_connection *conn = container_of(work, struct rds_connection, c_conn_w.work);
+	struct rds_conn_path *cp = container_of(work,
+						struct rds_conn_path,
+						cp_conn_w.work);
+	struct rds_connection *conn = cp->cp_conn;
 	int ret;
 
-	clear_bit(RDS_RECONNECT_PENDING, &conn->c_flags);
-	if (rds_conn_transition(conn, RDS_CONN_DOWN, RDS_CONN_CONNECTING)) {
+	clear_bit(RDS_RECONNECT_PENDING, &cp->cp_flags);
+	if (rds_conn_path_transition(cp, RDS_CONN_DOWN, RDS_CONN_CONNECTING)) {
 		ret = conn->c_trans->conn_connect(conn);
 		rdsdebug("conn %p for %pI4 to %pI4 dispatched, ret %d\n",
 			conn, &conn->c_laddr, &conn->c_faddr, ret);
 
 		if (ret) {
-			if (rds_conn_transition(conn, RDS_CONN_CONNECTING, RDS_CONN_DOWN))
-				rds_queue_reconnect(conn);
+			if (rds_conn_path_transition(cp,
+						     RDS_CONN_CONNECTING,
+						     RDS_CONN_DOWN))
+				rds_queue_reconnect(cp);
 			else
 				rds_conn_error(conn, "RDS: connect failed\n");
 		}
@@ -164,22 +170,24 @@ void rds_connect_worker(struct work_struct *work)
 
 void rds_send_worker(struct work_struct *work)
 {
-	struct rds_connection *conn = container_of(work, struct rds_connection, c_send_w.work);
+	struct rds_conn_path *cp = container_of(work,
+						struct rds_conn_path,
+						cp_send_w.work);
 	int ret;
 
-	if (rds_conn_state(conn) == RDS_CONN_UP) {
-		clear_bit(RDS_LL_SEND_FULL, &conn->c_flags);
-		ret = rds_send_xmit(conn);
+	if (rds_conn_path_state(cp) == RDS_CONN_UP) {
+		clear_bit(RDS_LL_SEND_FULL, &cp->cp_flags);
+		ret = rds_send_xmit(cp->cp_conn);
 		cond_resched();
-		rdsdebug("conn %p ret %d\n", conn, ret);
+		rdsdebug("conn %p ret %d\n", cp->cp_conn, ret);
 		switch (ret) {
 		case -EAGAIN:
 			rds_stats_inc(s_send_immediate_retry);
-			queue_delayed_work(rds_wq, &conn->c_send_w, 0);
+			queue_delayed_work(rds_wq, &cp->cp_send_w, 0);
 			break;
 		case -ENOMEM:
 			rds_stats_inc(s_send_delayed_retry);
-			queue_delayed_work(rds_wq, &conn->c_send_w, 2);
+			queue_delayed_work(rds_wq, &cp->cp_send_w, 2);
 		default:
 			break;
 		}
@@ -188,20 +196,22 @@ void rds_send_worker(struct work_struct *work)
 
 void rds_recv_worker(struct work_struct *work)
 {
-	struct rds_connection *conn = container_of(work, struct rds_connection, c_recv_w.work);
+	struct rds_conn_path *cp = container_of(work,
+						struct rds_conn_path,
+						cp_recv_w.work);
 	int ret;
 
-	if (rds_conn_state(conn) == RDS_CONN_UP) {
-		ret = conn->c_trans->recv(conn);
-		rdsdebug("conn %p ret %d\n", conn, ret);
+	if (rds_conn_path_state(cp) == RDS_CONN_UP) {
+		ret = cp->cp_conn->c_trans->recv(cp->cp_conn);
+		rdsdebug("conn %p ret %d\n", cp->cp_conn, ret);
 		switch (ret) {
 		case -EAGAIN:
 			rds_stats_inc(s_recv_immediate_retry);
-			queue_delayed_work(rds_wq, &conn->c_recv_w, 0);
+			queue_delayed_work(rds_wq, &cp->cp_recv_w, 0);
 			break;
 		case -ENOMEM:
 			rds_stats_inc(s_recv_delayed_retry);
-			queue_delayed_work(rds_wq, &conn->c_recv_w, 2);
+			queue_delayed_work(rds_wq, &cp->cp_recv_w, 2);
 		default:
 			break;
 		}
@@ -210,9 +220,11 @@ void rds_recv_worker(struct work_struct *work)
 
 void rds_shutdown_worker(struct work_struct *work)
 {
-	struct rds_connection *conn = container_of(work, struct rds_connection, c_down_w);
+	struct rds_conn_path *cp = container_of(work,
+						struct rds_conn_path,
+						cp_down_w);
 
-	rds_conn_shutdown(conn);
+	rds_conn_shutdown(cp->cp_conn);
 }
 
 void rds_threads_exit(void)