IB/mad: Allow tuning of QP0 and QP1 sizes

MADs are UD and can be dropped if there are no receives posted, so
allow receive queue size to be set with a module parameter in case the
queue needs to be lengthened.  Send side tuning is done for symmetry
with receive.
Signed-off-by: Hal Rosenstock <hal.rosenstock@gmail.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

drivers/infiniband/core/mad.c

@@ -2,6 +2,7 @@
  * Copyright (c) 2004-2007 Voltaire, Inc. All rights reserved.
  * Copyright (c) 2005 Intel Corporation.  All rights reserved.
  * Copyright (c) 2005 Mellanox Technologies Ltd.  All rights reserved.
+ * Copyright (c) 2009 HNR Consulting. All rights reserved.
  *
  * This software is available to you under a choice of one of two
  * licenses.  You may choose to be licensed under the terms of the GNU
@@ -45,6 +46,14 @@ MODULE_DESCRIPTION("kernel IB MAD API");
 MODULE_AUTHOR("Hal Rosenstock");
 MODULE_AUTHOR("Sean Hefty");
 
+int mad_sendq_size = IB_MAD_QP_SEND_SIZE;
+int mad_recvq_size = IB_MAD_QP_RECV_SIZE;
+
+module_param_named(send_queue_size, mad_sendq_size, int, 0444);
+MODULE_PARM_DESC(send_queue_size, "Size of send queue in number of work requests");
+module_param_named(recv_queue_size, mad_recvq_size, int, 0444);
+MODULE_PARM_DESC(recv_queue_size, "Size of receive queue in number of work requests");
+
 static struct kmem_cache *ib_mad_cache;
 
 static struct list_head ib_mad_port_list;
@@ -2736,8 +2745,8 @@ static int create_mad_qp(struct ib_mad_qp_info *qp_info,
 	qp_init_attr.send_cq = qp_info->port_priv->cq;
 	qp_init_attr.recv_cq = qp_info->port_priv->cq;
 	qp_init_attr.sq_sig_type = IB_SIGNAL_ALL_WR;
-	qp_init_attr.cap.max_send_wr = IB_MAD_QP_SEND_SIZE;
-	qp_init_attr.cap.max_recv_wr = IB_MAD_QP_RECV_SIZE;
+	qp_init_attr.cap.max_send_wr = mad_sendq_size;
+	qp_init_attr.cap.max_recv_wr = mad_recvq_size;
 	qp_init_attr.cap.max_send_sge = IB_MAD_SEND_REQ_MAX_SG;
 	qp_init_attr.cap.max_recv_sge = IB_MAD_RECV_REQ_MAX_SG;
 	qp_init_attr.qp_type = qp_type;
@@ -2752,8 +2761,8 @@ static int create_mad_qp(struct ib_mad_qp_info *qp_info,
 		goto error;
 	}
 	/* Use minimum queue sizes unless the CQ is resized */
-	qp_info->send_queue.max_active = IB_MAD_QP_SEND_SIZE;
-	qp_info->recv_queue.max_active = IB_MAD_QP_RECV_SIZE;
+	qp_info->send_queue.max_active = mad_sendq_size;
+	qp_info->recv_queue.max_active = mad_recvq_size;
 	return 0;
 
 error:
@@ -2792,7 +2801,7 @@ static int ib_mad_port_open(struct ib_device *device,
 	init_mad_qp(port_priv, &port_priv->qp_info[0]);
 	init_mad_qp(port_priv, &port_priv->qp_info[1]);
 
-	cq_size = (IB_MAD_QP_SEND_SIZE + IB_MAD_QP_RECV_SIZE) * 2;
+	cq_size = (mad_sendq_size + mad_recvq_size) * 2;
 	port_priv->cq = ib_create_cq(port_priv->device,
 				     ib_mad_thread_completion_handler,
 				     NULL, port_priv, cq_size, 0);
@@ -2984,6 +2993,12 @@ static int __init ib_mad_init_module(void)
 {
 	int ret;
 
+	mad_recvq_size = min(mad_recvq_size, IB_MAD_QP_MAX_SIZE);
+	mad_recvq_size = max(mad_recvq_size, IB_MAD_QP_MIN_SIZE);
+
+	mad_sendq_size = min(mad_sendq_size, IB_MAD_QP_MAX_SIZE);
+	mad_sendq_size = max(mad_sendq_size, IB_MAD_QP_MIN_SIZE);
+
 	spin_lock_init(&ib_mad_port_list_lock);
 
 	ib_mad_cache = kmem_cache_create("ib_mad",

drivers/infiniband/core/mad_priv.h

@@ -2,6 +2,7 @@
  * Copyright (c) 2004, 2005, Voltaire, Inc. All rights reserved.
  * Copyright (c) 2005 Intel Corporation. All rights reserved.
  * Copyright (c) 2005 Sun Microsystems, Inc. All rights reserved.
+ * Copyright (c) 2009 HNR Consulting. All rights reserved.
  *
  * This software is available to you under a choice of one of two
  * licenses.  You may choose to be licensed under the terms of the GNU
@@ -49,6 +50,8 @@
 /* QP and CQ parameters */
 #define IB_MAD_QP_SEND_SIZE	128
 #define IB_MAD_QP_RECV_SIZE	512
+#define IB_MAD_QP_MIN_SIZE	64
+#define IB_MAD_QP_MAX_SIZE	8192
 #define IB_MAD_SEND_REQ_MAX_SG	2
 #define IB_MAD_RECV_REQ_MAX_SG	1