RDS: TCP: Enable multipath RDS for TCP
Use RDS probe-ping to compute how many paths may be used with
the peer, and to synchronously start the multiple paths. If mprds is
supported, hash outgoing traffic to one of multiple paths in rds_sendmsg()
when multipath RDS is supported by the transport.
CC: Santosh Shilimkar <santosh.shilimkar@oracle.com>
Signed-off-by: Sowmini Varadhan <sowmini.varadhan@oracle.com>
Acked-by: Santosh Shilimkar <santosh.shilimkar@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/rds/rds.h b/net/rds/rds.h
index 6ef07bd..b2d17f0 100644
--- a/net/rds/rds.h
+++ b/net/rds/rds.h
@@ -85,7 +85,9 @@
#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 @@
__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 @@
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 @@
#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 @@
__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 @@
/* 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)