RDS: TCP: Enable multipath RDS for TCP

[cascardo/linux.git] / net / rds / rds.h

diff --git a/net/rds/rds.h b/net/rds/rds.h
index 6ef07bd..b2d17f0 100644 (file)
--- a/net/rds/rds.h
+++ b/net/rds/rds.h
@@ -85,7 +85,9 @@ enum {
 #define RDS_RECV_REFILL                3
 
 /* Max number of multipaths per RDS connection. Must be a power of 2 */
-#define        RDS_MPATH_WORKERS       1
+#define        RDS_MPATH_WORKERS       8
+#define        RDS_MPATH_HASH(rs, n) (jhash_1word((rs)->rs_bound_port, \
+                              (rs)->rs_hash_initval) & ((n) - 1))
 
 /* Per mpath connection state */
 struct rds_conn_path {
@@ -131,7 +133,8 @@ struct rds_connection {
        __be32                  c_laddr;
        __be32                  c_faddr;
        unsigned int            c_loopback:1,
-                               c_pad_to_32:31;
+                               c_ping_triggered:1,
+                               c_pad_to_32:30;
        int                     c_npaths;
        struct rds_connection   *c_passive;
        struct rds_transport    *c_trans;
@@ -147,6 +150,7 @@ struct rds_connection {
        unsigned long           c_map_queued;
 
        struct rds_conn_path    c_path[RDS_MPATH_WORKERS];
+       wait_queue_head_t       c_hs_waitq; /* handshake waitq */
 };
 
 static inline
@@ -166,6 +170,17 @@ void rds_conn_net_set(struct rds_connection *conn, struct net *net)
 #define RDS_FLAG_RETRANSMITTED 0x04
 #define RDS_MAX_ADV_CREDIT     255
 
+/* RDS_FLAG_PROBE_PORT is the reserved sport used for sending a ping
+ * probe to exchange control information before establishing a connection.
+ * Currently the control information that is exchanged is the number of
+ * supported paths. If the peer is a legacy (older kernel revision) peer,
+ * it would return a pong message without additional control information
+ * that would then alert the sender that the peer was an older rev.
+ */
+#define RDS_FLAG_PROBE_PORT    1
+#define        RDS_HS_PROBE(sport, dport) \
+               ((sport == RDS_FLAG_PROBE_PORT && dport == 0) || \
+                (sport == 0 && dport == RDS_FLAG_PROBE_PORT))
 /*
  * Maximum space available for extension headers.
  */
@@ -225,6 +240,11 @@ struct rds_ext_header_rdma_dest {
        __be32                  h_rdma_offset;
 };
 
+/* Extension header announcing number of paths.
+ * Implicit length = 2 bytes.
+ */
+#define RDS_EXTHDR_NPATHS      4
+
 #define __RDS_EXTHDR_MAX       16 /* for now */
 
 struct rds_incoming {
@@ -545,6 +565,7 @@ struct rds_sock {
        /* Socket options - in case there will be more */
        unsigned char           rs_recverr,
                                rs_cong_monitor;
+       u32                     rs_hash_initval;
 };
 
 static inline struct rds_sock *rds_sk_to_rs(const struct sock *sk)