IB/iser: Re-adjust CQ and QP send ring sizes to HW limits

Re-adjust max CQEs per CQ and max send_wr per QP according
to the resource limits supported by underlying hardware.
Signed-off-by: Minh Tran <minhduc.tran@emulex.com>
Signed-off-by: Jayamohan Kallickal <jayamohan.kallickal@emulex.com>
Acked-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>

drivers/infiniband/ulp/iser/iscsi_iser.c

@@ -569,6 +569,7 @@ iscsi_iser_session_create(struct iscsi_endpoint *ep,
 	struct Scsi_Host *shost;
 	struct iser_conn *iser_conn = NULL;
 	struct ib_conn *ib_conn;
+	u16 max_cmds;
 
 	shost = iscsi_host_alloc(&iscsi_iser_sht, 0, 0);
 	if (!shost)
@@ -586,6 +587,7 @@ iscsi_iser_session_create(struct iscsi_endpoint *ep,
 	 */
 	if (ep) {
 		iser_conn = ep->dd_data;
+		max_cmds = iser_conn->max_cmds;
 		ib_conn = &iser_conn->ib_conn;
 		if (ib_conn->pi_support) {
 			u32 sig_caps = ib_conn->device->dev_attr.sig_prot_cap;
@@ -596,16 +598,18 @@ iscsi_iser_session_create(struct iscsi_endpoint *ep,
 			else
 				scsi_host_set_guard(shost, SHOST_DIX_GUARD_CRC);
 		}
+	} else {
+		max_cmds = ISER_DEF_XMIT_CMDS_MAX;
 	}
 
 	if (iscsi_host_add(shost, ep ?
 			   ib_conn->device->ib_device->dma_device : NULL))
 		goto free_host;
 
-	if (cmds_max > ISER_DEF_XMIT_CMDS_MAX) {
+	if (cmds_max > max_cmds) {
 		iser_info("cmds_max changed from %u to %u\n",
-			  cmds_max, ISER_DEF_XMIT_CMDS_MAX);
-		cmds_max = ISER_DEF_XMIT_CMDS_MAX;
+			  cmds_max, max_cmds);
+		cmds_max = max_cmds;
 	}
 
 	cls_session = iscsi_session_setup(&iscsi_iser_transport, shost,

drivers/infiniband/ulp/iser/iscsi_iser.h

@@ -144,6 +144,11 @@
 					ISER_MAX_TX_MISC_PDUS         + \
 					ISER_MAX_RX_MISC_PDUS)
 
+#define ISER_GET_MAX_XMIT_CMDS(send_wr) ((send_wr			\
+					 - ISER_MAX_TX_MISC_PDUS	\
+					 - ISER_MAX_RX_MISC_PDUS) /	\
+					 (1 + ISER_INFLIGHT_DATAOUTS))
+
 #define ISER_WC_BATCH_COUNT   16
 #define ISER_SIGNAL_CMD_COUNT 32
 
@@ -482,6 +487,7 @@ struct ib_conn {
  *                    to max number of post recvs
  * @qp_max_recv_dtos_mask: (qp_max_recv_dtos - 1)
  * @min_posted_rx:    (qp_max_recv_dtos >> 2)
+ * @max_cmds:         maximum cmds allowed for this connection
  * @name:             connection peer portal
  * @release_work:     deffered work for release job
  * @state_mutex:      protects iser onnection state
@@ -507,6 +513,7 @@ struct iser_conn {
 	unsigned		     qp_max_recv_dtos;
 	unsigned		     qp_max_recv_dtos_mask;
 	unsigned		     min_posted_rx;
+	u16                          max_cmds;
 	char 			     name[ISER_OBJECT_NAME_SIZE];
 	struct work_struct	     release_work;
 	struct mutex		     state_mutex;

drivers/infiniband/ulp/iser/iser_verbs.c

@@ -76,7 +76,7 @@ static void iser_event_handler(struct ib_event_handler *handler,
 static int iser_create_device_ib_res(struct iser_device *device)
 {
 	struct ib_device_attr *dev_attr = &device->dev_attr;
-	int ret, i;
+	int ret, i, max_cqe;
 
 	ret = ib_query_device(device->ib_device, dev_attr);
 	if (ret) {
@@ -106,9 +106,12 @@ static int iser_create_device_ib_res(struct iser_device *device)
 
 	device->comps_used = min(ISER_MAX_CQ,
 				 device->ib_device->num_comp_vectors);
-	iser_info("using %d CQs, device %s supports %d vectors\n",
+
+	max_cqe = min(ISER_MAX_CQ_LEN, dev_attr->max_cqe);
+
+	iser_info("using %d CQs, device %s supports %d vectors max_cqe %d\n",
 		  device->comps_used, device->ib_device->name,
-		  device->ib_device->num_comp_vectors);
+		  device->ib_device->num_comp_vectors, max_cqe);
 
 	device->pd = ib_alloc_pd(device->ib_device);
 	if (IS_ERR(device->pd))
@@ -122,7 +125,7 @@ static int iser_create_device_ib_res(struct iser_device *device)
 					iser_cq_callback,
 					iser_cq_event_callback,
 					(void *)comp,
-					ISER_MAX_CQ_LEN, i);
+					max_cqe, i);
 		if (IS_ERR(comp->cq)) {
 			comp->cq = NULL;
 			goto cq_err;
@@ -425,7 +428,10 @@ void iser_free_fastreg_pool(struct ib_conn *ib_conn)
  */
 static int iser_create_ib_conn_res(struct ib_conn *ib_conn)
 {
+	struct iser_conn *iser_conn = container_of(ib_conn, struct iser_conn,
+						   ib_conn);
 	struct iser_device	*device;
+	struct ib_device_attr *dev_attr;
 	struct ib_qp_init_attr	init_attr;
 	int			ret = -ENOMEM;
 	int index, min_index = 0;
@@ -433,6 +439,7 @@ static int iser_create_ib_conn_res(struct ib_conn *ib_conn)
 	BUG_ON(ib_conn->device == NULL);
 
 	device = ib_conn->device;
+	dev_attr = &device->dev_attr;
 
 	memset(&init_attr, 0, sizeof init_attr);
 
@@ -460,8 +467,20 @@ static int iser_create_ib_conn_res(struct ib_conn *ib_conn)
 	if (ib_conn->pi_support) {
 		init_attr.cap.max_send_wr = ISER_QP_SIG_MAX_REQ_DTOS + 1;
 		init_attr.create_flags |= IB_QP_CREATE_SIGNATURE_EN;
+		iser_conn->max_cmds =
+			ISER_GET_MAX_XMIT_CMDS(ISER_QP_SIG_MAX_REQ_DTOS);
 	} else {
+		if (dev_attr->max_qp_wr > ISER_QP_MAX_REQ_DTOS) {
 			init_attr.cap.max_send_wr  = ISER_QP_MAX_REQ_DTOS + 1;
+			iser_conn->max_cmds =
+				ISER_GET_MAX_XMIT_CMDS(ISER_QP_MAX_REQ_DTOS);
+		} else {
+			init_attr.cap.max_send_wr = dev_attr->max_qp_wr;
+			iser_conn->max_cmds =
+				ISER_GET_MAX_XMIT_CMDS(dev_attr->max_qp_wr);
+			iser_dbg("device %s supports max_send_wr %d\n",
+				 device->ib_device->name, dev_attr->max_qp_wr);
+		}
 	}
 
 	ret = rdma_create_qp(ib_conn->cma_id, device->pd, &init_attr);