RDS: IB: split send completion handling and do batch ack

Similar to what we did with receive CQ completion handling, we split
the transmit completion handler so that it lets us implement batched
work completion handling.

We re-use the cq_poll routine and makes use of RDS_IB_SEND_OP to
identify the send vs receive completion event handler invocation.

Signed-off-by: Santosh Shilimkar <ssantosh@kernel.org>
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@oracle.com>
diff --git a/net/rds/send.c b/net/rds/send.c
index a081a64..ee49c25 100644
--- a/net/rds/send.c
+++ b/net/rds/send.c
@@ -432,6 +432,7 @@
 out:
 	return ret;
 }
+EXPORT_SYMBOL_GPL(rds_send_xmit);
 
 static void rds_send_sndbuf_remove(struct rds_sock *rs, struct rds_message *rm)
 {