IB/isert: Support the remote invalidation exception

We'll use remote invalidate, according to negotiation result
during connection establishment. If the initiator declared that
it supports the remote invalidate exception and the local HCA
supports IB_DEVICE_MEM_MGT_EXTENSIONS then the target will
use IB_WR_SEND_WITH_INV with the correct rkey for the response.

Signed-off-by: Jenny Derzhavetz <jennyf@mellanox.com>
Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Doug Ledford <dledford@redhat.com>

drivers/infiniband/ulp/isert/ib_isert.c

@@ -653,6 +653,32 @@ out_login_buf:
 	return ret;
 }
 
+static void
+isert_set_nego_params(struct isert_conn *isert_conn,
+		      struct rdma_conn_param *param)
+{
+	struct ib_device_attr *attr = &isert_conn->device->ib_device->attrs;
+
+	/* Set max inflight RDMA READ requests */
+	isert_conn->initiator_depth = min_t(u8, param->initiator_depth,
+				attr->max_qp_init_rd_atom);
+	isert_dbg("Using initiator_depth: %u\n", isert_conn->initiator_depth);
+
+	if (param->private_data) {
+		u8 flags = *(u8 *)param->private_data;
+
+		/*
+		 * use remote invalidation if the both initiator
+		 * and the HCA support it
+		 */
+		isert_conn->snd_w_inv = !(flags & ISER_SEND_W_INV_NOT_SUP) &&
+					  (attr->device_cap_flags &
+					   IB_DEVICE_MEM_MGT_EXTENSIONS);
+		if (isert_conn->snd_w_inv)
+			isert_info("Using remote invalidation\n");
+	}
+}
+
 static int
 isert_connect_request(struct rdma_cm_id *cma_id, struct rdma_cm_event *event)
 {
@@ -691,11 +717,7 @@ isert_connect_request(struct rdma_cm_id *cma_id, struct rdma_cm_event *event)
 	}
 	isert_conn->device = device;
 
-	/* Set max inflight RDMA READ requests */
-	isert_conn->initiator_depth = min_t(u8,
-				event->param.conn.initiator_depth,
-				device->ib_device->attrs.max_qp_init_rd_atom);
-	isert_dbg("Using initiator_depth: %u\n", isert_conn->initiator_depth);
+	isert_set_nego_params(isert_conn, &event->param.conn);
 
 	ret = isert_conn_setup_qp(isert_conn, cma_id);
 	if (ret)
@@ -1074,7 +1096,14 @@ isert_init_send_wr(struct isert_conn *isert_conn, struct isert_cmd *isert_cmd,
 
 	isert_cmd->rdma_wr.iser_ib_op = ISER_IB_SEND;
 	send_wr->wr_id = (uintptr_t)&isert_cmd->tx_desc;
-	send_wr->opcode = IB_WR_SEND;
+
+	if (isert_conn->snd_w_inv && isert_cmd->inv_rkey) {
+		send_wr->opcode  = IB_WR_SEND_WITH_INV;
+		send_wr->ex.invalidate_rkey = isert_cmd->inv_rkey;
+	} else {
+		send_wr->opcode = IB_WR_SEND;
+	}
+
 	send_wr->sg_list = &tx_desc->tx_sg[0];
 	send_wr->num_sge = isert_cmd->tx_desc.num_sge;
 	send_wr->send_flags = IB_SEND_SIGNALED;
@@ -1463,6 +1492,7 @@ isert_rx_opcode(struct isert_conn *isert_conn, struct iser_rx_desc *rx_desc,
 		isert_cmd->read_va = read_va;
 		isert_cmd->write_stag = write_stag;
 		isert_cmd->write_va = write_va;
+		isert_cmd->inv_rkey = read_stag ? read_stag : write_stag;
 
 		ret = isert_handle_scsi_cmd(isert_conn, isert_cmd, cmd,
 					rx_desc, (unsigned char *)hdr);
@@ -3080,7 +3110,9 @@ isert_rdma_accept(struct isert_conn *isert_conn)
 	cp.rnr_retry_count = 7;
 
 	memset(&rsp_hdr, 0, sizeof(rsp_hdr));
-	rsp_hdr.flags = (ISERT_ZBVA_NOT_USED | ISERT_SEND_W_INV_NOT_USED);
+	rsp_hdr.flags = ISERT_ZBVA_NOT_USED;
+	if (!isert_conn->snd_w_inv)
+		rsp_hdr.flags = rsp_hdr.flags | ISERT_SEND_W_INV_NOT_USED;
 	cp.private_data = (void *)&rsp_hdr;
 	cp.private_data_len = sizeof(rsp_hdr);
 

drivers/infiniband/ulp/isert/ib_isert.h

@@ -163,6 +163,7 @@ struct isert_cmd {
 	uint32_t		write_stag;
 	uint64_t		read_va;
 	uint64_t		write_va;
+	uint32_t		inv_rkey;
 	u64			pdu_buf_dma;
 	u32			pdu_buf_len;
 	struct isert_conn	*conn;
@@ -210,6 +211,7 @@ struct isert_conn {
 	struct work_struct	release_work;
 	struct ib_recv_wr       beacon;
 	bool                    logout_posted;
+	bool                    snd_w_inv;
 };
 
 #define ISERT_MAX_CQ 64