diff --git a/fs/cifs/smbdirect.c b/fs/cifs/smbdirect.c
index d785bc1..01bf418 100644
--- a/fs/cifs/smbdirect.c
+++ b/fs/cifs/smbdirect.c
@@ -17,6 +17,35 @@
 #include "smbdirect.h"
 #include "cifs_debug.h"
 
+static struct smbd_response *get_receive_buffer(
+		struct smbd_connection *info);
+static void put_receive_buffer(
+		struct smbd_connection *info,
+		struct smbd_response *response);
+static int allocate_receive_buffers(struct smbd_connection *info, int num_buf);
+static void destroy_receive_buffers(struct smbd_connection *info);
+
+static void enqueue_reassembly(
+		struct smbd_connection *info,
+		struct smbd_response *response, int data_length);
+static struct smbd_response *_get_first_reassembly(
+		struct smbd_connection *info);
+
+static int smbd_post_recv(
+		struct smbd_connection *info,
+		struct smbd_response *response);
+
+static int smbd_post_send_empty(struct smbd_connection *info);
+static int smbd_post_send_data(
+		struct smbd_connection *info,
+		struct kvec *iov, int n_vec, int remaining_data_length);
+static int smbd_post_send_page(struct smbd_connection *info,
+		struct page *page, unsigned long offset,
+		size_t size, int remaining_data_length);
+
+static void destroy_mr_list(struct smbd_connection *info);
+static int allocate_mr_list(struct smbd_connection *info);
+
 /* SMBD version number */
 #define SMBD_V1	0x0100
 
@@ -76,3 +105,2224 @@ static int max_frmr_depth = 2048;
 
 /* If payload is less than this byte, use RDMA send/recv not read/write */
 static int rdma_readwrite_threshold = 4096;
+
+/* Transport logging functions
+ * Logging are defined as classes. They can be OR'ed to define the actual
+ * logging level via module parameter smbd_logging_class
+ * e.g. cifs.smbd_logging_class=0x500 will log all log_rdma_recv() and
+ * log_rdma_event()
+ */
+#define LOG_CREDIT			0x1
+#define LOG_OUTGOING			0x2
+#define LOG_INCOMING			0x4
+#define LOG_RECEIVE_QUEUE		0x8
+#define LOG_REASSEMBLY_QUEUE		0x10
+#define LOG_READ			0x20
+#define LOG_WRITE			0x40
+#define LOG_RDMA_SEND			0x80
+#define LOG_RDMA_RECV			0x100
+#define LOG_KEEP_ALIVE			0x200
+#define LOG_RDMA_EVENT			0x400
+#define LOG_RDMA_MR			0X800
+
+static unsigned int smbd_logging_class = LOG_RDMA_MR;
+module_param(smbd_logging_class, uint, 0644);
+MODULE_PARM_DESC(smbd_logging_class,
+	"Logging class for SMBD transport 0x0 to 0xfff");
+
+#define log_rdma(class, fmt, args...)					\
+do {									\
+	if (class & smbd_logging_class)					\
+		cifs_dbg(VFS, "%s:%d " fmt, __func__, __LINE__, ##args);\
+} while (0)
+
+#define log_rdma_credit(fmt, args...)	log_rdma(LOG_CREDIT, fmt, ##args)
+#define log_outgoing(fmt, args...)	log_rdma(LOG_OUTGOING, fmt, ##args)
+#define log_incoming(fmt, args...)	log_rdma(LOG_INCOMING, fmt, ##args)
+#define log_receive_queue(fmt, args...)		\
+	log_rdma(LOG_RECEIVE_QUEUE, fmt, ##args)
+#define log_reassembly_queue(fmt, args...)	\
+		log_rdma(LOG_REASSEMBLY_QUEUE, fmt, ##args)
+#define log_read(fmt, args...)	log_rdma(LOG_READ, fmt, ##args)
+#define log_write(fmt, args...)	log_rdma(LOG_WRITE, fmt, ##args)
+#define log_rdma_send(fmt, args...)	log_rdma(LOG_RDMA_SEND, fmt, ##args)
+#define log_rdma_recv(fmt, args...)	log_rdma(LOG_RDMA_RECV, fmt, ##args)
+#define log_keep_alive(fmt, args...)	log_rdma(LOG_KEEP_ALIVE, fmt, ##args)
+#define log_rdma_event(fmt, args...)	log_rdma(LOG_RDMA_EVENT, fmt, ##args)
+#define log_rdma_mr(fmt, args...)	log_rdma(LOG_RDMA_MR, fmt, ##args)
+
+#define log_transport_credit(info)					\
+	log_rdma_credit("receive_credits %d receive_credit_target %d "	\
+			"send_credits %d send_credit_target %d\n",	\
+			atomic_read(&info->receive_credits),		\
+			info->receive_credit_target,			\
+			atomic_read(&info->send_credits),		\
+			info->send_credit_target)			\
+
+/*
+ * Destroy the transport and related RDMA and memory resources
+ * Need to go through all the pending counters and make sure on one is using
+ * the transport while it is destroyed
+ */
+static void smbd_destroy_rdma_work(struct work_struct *work)
+{
+	struct smbd_response *response;
+	struct smbd_connection *info =
+		container_of(work, struct smbd_connection, destroy_work);
+
+	log_rdma_event("cancelling all pending works\n");
+	cancel_delayed_work_sync(&info->idle_timer_work);
+	cancel_delayed_work_sync(&info->send_immediate_work);
+
+	ib_drain_qp(info->id->qp);
+	rdma_destroy_qp(info->id);
+
+	log_rdma_event("wait for all send or recv finish\n");
+	wait_event(info->wait_send_pending,
+		atomic_read(&info->send_pending) == 0);
+	wait_event(info->wait_send_payload_pending,
+		atomic_read(&info->send_payload_pending) == 0);
+	wait_event(info->wait_recv_pending,
+		atomic_read(&info->recv_pending) == 0);
+	wait_event(info->wait_read_pending,
+		atomic_read(&info->read_pending) == 0);
+	destroy_mr_list(info);
+
+	log_rdma_event("drain the reassembly queue\n");
+	do {
+		spin_lock(&info->reassembly_queue_lock);
+		response = _get_first_reassembly(info);
+		if (response) {
+			list_del(&response->list);
+			spin_unlock(&info->reassembly_queue_lock);
+			put_receive_buffer(info, response);
+		}
+	} while (response);
+	spin_unlock(&info->reassembly_queue_lock);
+	info->reassembly_data_length = 0;
+	wake_up_interruptible(&info->wait_reassembly_queue);
+
+	log_rdma_event("free receive buffers\n");
+	destroy_receive_buffers(info);
+
+	ib_free_cq(info->send_cq);
+	ib_free_cq(info->recv_cq);
+	ib_dealloc_pd(info->pd);
+	rdma_destroy_id(info->id);
+
+	/* free mempools */
+	mempool_destroy(info->request_mempool);
+	kmem_cache_destroy(info->request_cache);
+
+	mempool_destroy(info->response_mempool);
+	kmem_cache_destroy(info->response_cache);
+
+	info->transport_status = SMBD_DESTROYED;
+	wake_up_all(&info->wait_destroy);
+}
+
+static int smbd_process_disconnected(struct smbd_connection *info)
+{
+	schedule_work(&info->destroy_work);
+	return 0;
+}
+
+static void smbd_disconnect_rdma_work(struct work_struct *work)
+{
+	struct smbd_connection *info =
+		container_of(work, struct smbd_connection, disconnect_work);
+
+	if (info->transport_status == SMBD_CONNECTED) {
+		info->transport_status = SMBD_DISCONNECTING;
+		rdma_disconnect(info->id);
+	}
+}
+
+static void smbd_disconnect_rdma_connection(struct smbd_connection *info)
+{
+	schedule_work(&info->disconnect_work);
+}
+
+/* Upcall from RDMA CM */
+static int smbd_conn_upcall(
+		struct rdma_cm_id *id, struct rdma_cm_event *event)
+{
+	struct smbd_connection *info = id->context;
+
+	log_rdma_event("event=%d status=%d\n", event->event, event->status);
+
+	switch (event->event) {
+	case RDMA_CM_EVENT_ADDR_RESOLVED:
+	case RDMA_CM_EVENT_ROUTE_RESOLVED:
+		info->ri_rc = 0;
+		complete(&info->ri_done);
+		break;
+
+	case RDMA_CM_EVENT_ADDR_ERROR:
+		info->ri_rc = -EHOSTUNREACH;
+		complete(&info->ri_done);
+		break;
+
+	case RDMA_CM_EVENT_ROUTE_ERROR:
+		info->ri_rc = -ENETUNREACH;
+		complete(&info->ri_done);
+		break;
+
+	case RDMA_CM_EVENT_ESTABLISHED:
+	case RDMA_CM_EVENT_CONNECT_ERROR:
+	case RDMA_CM_EVENT_UNREACHABLE:
+	case RDMA_CM_EVENT_REJECTED:
+	case RDMA_CM_EVENT_DEVICE_REMOVAL:
+		log_rdma_event("connected event=%d\n", event->event);
+		info->connect_state = event->event;
+		info->transport_status = SMBD_CONNECTED;
+		wake_up_interruptible(&info->conn_wait);
+		break;
+
+	case RDMA_CM_EVENT_DISCONNECTED:
+		info->transport_status = SMBD_DISCONNECTED;
+		smbd_process_disconnected(info);
+		break;
+
+	default:
+		break;
+	}
+
+	return 0;
+}
+
+/* Upcall from RDMA QP */
+static void
+smbd_qp_async_error_upcall(struct ib_event *event, void *context)
+{
+	struct smbd_connection *info = context;
+
+	log_rdma_event("%s on device %s info %p\n",
+		ib_event_msg(event->event), event->device->name, info);
+
+	switch (event->event) {
+	case IB_EVENT_CQ_ERR:
+	case IB_EVENT_QP_FATAL:
+		smbd_disconnect_rdma_connection(info);
+
+	default:
+		break;
+	}
+}
+
+static inline void *smbd_request_payload(struct smbd_request *request)
+{
+	return (void *)request->packet;
+}
+
+static inline void *smbd_response_payload(struct smbd_response *response)
+{
+	return (void *)response->packet;
+}
+
+/* Called when a RDMA send is done */
+static void send_done(struct ib_cq *cq, struct ib_wc *wc)
+{
+	int i;
+	struct smbd_request *request =
+		container_of(wc->wr_cqe, struct smbd_request, cqe);
+
+	log_rdma_send("smbd_request %p completed wc->status=%d\n",
+		request, wc->status);
+
+	if (wc->status != IB_WC_SUCCESS || wc->opcode != IB_WC_SEND) {
+		log_rdma_send("wc->status=%d wc->opcode=%d\n",
+			wc->status, wc->opcode);
+	}
+
+	for (i = 0; i < request->num_sge; i++)
+		ib_dma_unmap_single(request->info->id->device,
+			request->sge[i].addr,
+			request->sge[i].length,
+			DMA_TO_DEVICE);
+
+	if (request->has_payload) {
+		if (atomic_dec_and_test(&request->info->send_payload_pending))
+			wake_up(&request->info->wait_send_payload_pending);
+	} else {
+		if (atomic_dec_and_test(&request->info->send_pending))
+			wake_up(&request->info->wait_send_pending);
+	}
+
+	mempool_free(request, request->info->request_mempool);
+}
+
+static void dump_smbd_negotiate_resp(struct smbd_negotiate_resp *resp)
+{
+	log_rdma_event("resp message min_version %u max_version %u "
+		"negotiated_version %u credits_requested %u "
+		"credits_granted %u status %u max_readwrite_size %u "
+		"preferred_send_size %u max_receive_size %u "
+		"max_fragmented_size %u\n",
+		resp->min_version, resp->max_version, resp->negotiated_version,
+		resp->credits_requested, resp->credits_granted, resp->status,
+		resp->max_readwrite_size, resp->preferred_send_size,
+		resp->max_receive_size, resp->max_fragmented_size);
+}
+
+/*
+ * Process a negotiation response message, according to [MS-SMBD]3.1.5.7
+ * response, packet_length: the negotiation response message
+ * return value: true if negotiation is a success, false if failed
+ */
+static bool process_negotiation_response(
+		struct smbd_response *response, int packet_length)
+{
+	struct smbd_connection *info = response->info;
+	struct smbd_negotiate_resp *packet = smbd_response_payload(response);
+
+	if (packet_length < sizeof(struct smbd_negotiate_resp)) {
+		log_rdma_event("error: packet_length=%d\n", packet_length);
+		return false;
+	}
+
+	if (le16_to_cpu(packet->negotiated_version) != SMBD_V1) {
+		log_rdma_event("error: negotiated_version=%x\n",
+			le16_to_cpu(packet->negotiated_version));
+		return false;
+	}
+	info->protocol = le16_to_cpu(packet->negotiated_version);
+
+	if (packet->credits_requested == 0) {
+		log_rdma_event("error: credits_requested==0\n");
+		return false;
+	}
+	info->receive_credit_target = le16_to_cpu(packet->credits_requested);
+
+	if (packet->credits_granted == 0) {
+		log_rdma_event("error: credits_granted==0\n");
+		return false;
+	}
+	atomic_set(&info->send_credits, le16_to_cpu(packet->credits_granted));
+
+	atomic_set(&info->receive_credits, 0);
+
+	if (le32_to_cpu(packet->preferred_send_size) > info->max_receive_size) {
+		log_rdma_event("error: preferred_send_size=%d\n",
+			le32_to_cpu(packet->preferred_send_size));
+		return false;
+	}
+	info->max_receive_size = le32_to_cpu(packet->preferred_send_size);
+
+	if (le32_to_cpu(packet->max_receive_size) < SMBD_MIN_RECEIVE_SIZE) {
+		log_rdma_event("error: max_receive_size=%d\n",
+			le32_to_cpu(packet->max_receive_size));
+		return false;
+	}
+	info->max_send_size = min_t(int, info->max_send_size,
+					le32_to_cpu(packet->max_receive_size));
+
+	if (le32_to_cpu(packet->max_fragmented_size) <
+			SMBD_MIN_FRAGMENTED_SIZE) {
+		log_rdma_event("error: max_fragmented_size=%d\n",
+			le32_to_cpu(packet->max_fragmented_size));
+		return false;
+	}
+	info->max_fragmented_send_size =
+		le32_to_cpu(packet->max_fragmented_size);
+	info->rdma_readwrite_threshold =
+		rdma_readwrite_threshold > info->max_fragmented_send_size ?
+		info->max_fragmented_send_size :
+		rdma_readwrite_threshold;
+
+
+	info->max_readwrite_size = min_t(u32,
+			le32_to_cpu(packet->max_readwrite_size),
+			info->max_frmr_depth * PAGE_SIZE);
+	info->max_frmr_depth = info->max_readwrite_size / PAGE_SIZE;
+
+	return true;
+}
+
+/*
+ * Check and schedule to send an immediate packet
+ * This is used to extend credtis to remote peer to keep the transport busy
+ */
+static void check_and_send_immediate(struct smbd_connection *info)
+{
+	if (info->transport_status != SMBD_CONNECTED)
+		return;
+
+	info->send_immediate = true;
+
+	/*
+	 * Promptly send a packet if our peer is running low on receive
+	 * credits
+	 */
+	if (atomic_read(&info->receive_credits) <
+		info->receive_credit_target - 1)
+		queue_delayed_work(
+			info->workqueue, &info->send_immediate_work, 0);
+}
+
+/* Called from softirq, when recv is done */
+static void recv_done(struct ib_cq *cq, struct ib_wc *wc)
+{
+	struct smbd_data_transfer *data_transfer;
+	struct smbd_response *response =
+		container_of(wc->wr_cqe, struct smbd_response, cqe);
+	struct smbd_connection *info = response->info;
+
+	log_rdma_recv("response=%p type=%d wc status=%d wc opcode %d "
+		      "byte_len=%d pkey_index=%x\n",
+		response, response->type, wc->status, wc->opcode,
+		wc->byte_len, wc->pkey_index);
+
+	if (wc->status != IB_WC_SUCCESS || wc->opcode != IB_WC_RECV) {
+		log_rdma_recv("wc->status=%d opcode=%d\n",
+			wc->status, wc->opcode);
+		goto error;
+	}
+
+	ib_dma_sync_single_for_cpu(
+		wc->qp->device,
+		response->sge.addr,
+		response->sge.length,
+		DMA_FROM_DEVICE);
+
+	switch (response->type) {
+	/* SMBD negotiation response */
+	case SMBD_NEGOTIATE_RESP:
+		dump_smbd_negotiate_resp(smbd_response_payload(response));
+		info->full_packet_received = true;
+		info->negotiate_done =
+			process_negotiation_response(response, wc->byte_len);
+		complete(&info->negotiate_completion);
+		break;
+
+	/* SMBD data transfer packet */
+	case SMBD_TRANSFER_DATA:
+		data_transfer = smbd_response_payload(response);
+		atomic_dec(&info->receive_credits);
+		info->receive_credit_target =
+			le16_to_cpu(data_transfer->credits_requested);
+		atomic_add(le16_to_cpu(data_transfer->credits_granted),
+			&info->send_credits);
+
+		log_incoming("data flags %d data_offset %d data_length %d "
+			     "remaining_data_length %d\n",
+			le16_to_cpu(data_transfer->flags),
+			le32_to_cpu(data_transfer->data_offset),
+			le32_to_cpu(data_transfer->data_length),
+			le32_to_cpu(data_transfer->remaining_data_length));
+
+		log_transport_credit(info);
+
+		/*
+		 * We may have new send credits granted from remote peer
+		 * If any sender is blcoked on lack of credets, unblock it
+		 */
+		if (atomic_read(&info->send_credits))
+			wake_up_interruptible(&info->wait_send_queue);
+
+		/* Send a KEEP_ALIVE response right away if requested */
+		info->keep_alive_requested = KEEP_ALIVE_NONE;
+		if (le16_to_cpu(data_transfer->flags) &
+				le16_to_cpu(SMB_DIRECT_RESPONSE_REQUESTED)) {
+			info->keep_alive_requested = KEEP_ALIVE_PENDING;
+		}
+
+		/*
+		 * Check if we need to send something to remote peer to
+		 * grant more credits or respond to KEEP_ALIVE packet
+		 */
+		check_and_send_immediate(info);
+
+		/*
+		 * If this is a packet with data playload place the data in
+		 * reassembly queue and wake up the reading thread
+		 */
+		if (le32_to_cpu(data_transfer->data_length)) {
+			if (info->full_packet_received)
+				response->first_segment = true;
+
+			if (le32_to_cpu(data_transfer->remaining_data_length))
+				info->full_packet_received = false;
+			else
+				info->full_packet_received = true;
+
+			enqueue_reassembly(
+				info,
+				response,
+				le32_to_cpu(data_transfer->data_length));
+
+			wake_up_interruptible(&info->wait_reassembly_queue);
+			goto queue_done;
+		}
+
+		/* This is an empty packet, finish it */
+		break;
+
+	default:
+		log_rdma_recv("unexpected response type=%d\n", response->type);
+	}
+
+error:
+	put_receive_buffer(info, response);
+
+queue_done:
+	if (atomic_dec_and_test(&info->recv_pending))
+		wake_up(&info->wait_recv_pending);
+}
+
+static struct rdma_cm_id *smbd_create_id(
+		struct smbd_connection *info,
+		struct sockaddr *dstaddr, int port)
+{
+	struct rdma_cm_id *id;
+	int rc;
+	__be16 *sport;
+
+	id = rdma_create_id(&init_net, smbd_conn_upcall, info,
+		RDMA_PS_TCP, IB_QPT_RC);
+	if (IS_ERR(id)) {
+		rc = PTR_ERR(id);
+		log_rdma_event("rdma_create_id() failed %i\n", rc);
+		return id;
+	}
+
+	if (dstaddr->sa_family == AF_INET6)
+		sport = &((struct sockaddr_in6 *)dstaddr)->sin6_port;
+	else
+		sport = &((struct sockaddr_in *)dstaddr)->sin_port;
+
+	*sport = htons(port);
+
+	init_completion(&info->ri_done);
+	info->ri_rc = -ETIMEDOUT;
+
+	rc = rdma_resolve_addr(id, NULL, (struct sockaddr *)dstaddr,
+		RDMA_RESOLVE_TIMEOUT);
+	if (rc) {
+		log_rdma_event("rdma_resolve_addr() failed %i\n", rc);
+		goto out;
+	}
+	wait_for_completion_interruptible_timeout(
+		&info->ri_done, msecs_to_jiffies(RDMA_RESOLVE_TIMEOUT));
+	rc = info->ri_rc;
+	if (rc) {
+		log_rdma_event("rdma_resolve_addr() completed %i\n", rc);
+		goto out;
+	}
+
+	info->ri_rc = -ETIMEDOUT;
+	rc = rdma_resolve_route(id, RDMA_RESOLVE_TIMEOUT);
+	if (rc) {
+		log_rdma_event("rdma_resolve_route() failed %i\n", rc);
+		goto out;
+	}
+	wait_for_completion_interruptible_timeout(
+		&info->ri_done, msecs_to_jiffies(RDMA_RESOLVE_TIMEOUT));
+	rc = info->ri_rc;
+	if (rc) {
+		log_rdma_event("rdma_resolve_route() completed %i\n", rc);
+		goto out;
+	}
+
+	return id;
+
+out:
+	rdma_destroy_id(id);
+	return ERR_PTR(rc);
+}
+
+/*
+ * Test if FRWR (Fast Registration Work Requests) is supported on the device
+ * This implementation requries FRWR on RDMA read/write
+ * return value: true if it is supported
+ */
+static bool frwr_is_supported(struct ib_device_attr *attrs)
+{
+	if (!(attrs->device_cap_flags & IB_DEVICE_MEM_MGT_EXTENSIONS))
+		return false;
+	if (attrs->max_fast_reg_page_list_len == 0)
+		return false;
+	return true;
+}
+
+static int smbd_ia_open(
+		struct smbd_connection *info,
+		struct sockaddr *dstaddr, int port)
+{
+	int rc;
+
+	info->id = smbd_create_id(info, dstaddr, port);
+	if (IS_ERR(info->id)) {
+		rc = PTR_ERR(info->id);
+		goto out1;
+	}
+
+	if (!frwr_is_supported(&info->id->device->attrs)) {
+		log_rdma_event(
+			"Fast Registration Work Requests "
+			"(FRWR) is not supported\n");
+		log_rdma_event(
+			"Device capability flags = %llx "
+			"max_fast_reg_page_list_len = %u\n",
+			info->id->device->attrs.device_cap_flags,
+			info->id->device->attrs.max_fast_reg_page_list_len);
+		rc = -EPROTONOSUPPORT;
+		goto out2;
+	}
+	info->max_frmr_depth = min_t(int,
+		max_frmr_depth,
+		info->id->device->attrs.max_fast_reg_page_list_len);
+	info->mr_type = IB_MR_TYPE_MEM_REG;
+	if (info->id->device->attrs.device_cap_flags & IB_DEVICE_SG_GAPS_REG)
+		info->mr_type = IB_MR_TYPE_SG_GAPS;
+
+	info->pd = ib_alloc_pd(info->id->device, 0);
+	if (IS_ERR(info->pd)) {
+		rc = PTR_ERR(info->pd);
+		log_rdma_event("ib_alloc_pd() returned %d\n", rc);
+		goto out2;
+	}
+
+	return 0;
+
+out2:
+	rdma_destroy_id(info->id);
+	info->id = NULL;
+
+out1:
+	return rc;
+}
+
+/*
+ * Send a negotiation request message to the peer
+ * The negotiation procedure is in [MS-SMBD] 3.1.5.2 and 3.1.5.3
+ * After negotiation, the transport is connected and ready for
+ * carrying upper layer SMB payload
+ */
+static int smbd_post_send_negotiate_req(struct smbd_connection *info)
+{
+	struct ib_send_wr send_wr, *send_wr_fail;
+	int rc = -ENOMEM;
+	struct smbd_request *request;
+	struct smbd_negotiate_req *packet;
+
+	request = mempool_alloc(info->request_mempool, GFP_KERNEL);
+	if (!request)
+		return rc;
+
+	request->info = info;
+
+	packet = smbd_request_payload(request);
+	packet->min_version = cpu_to_le16(SMBD_V1);
+	packet->max_version = cpu_to_le16(SMBD_V1);
+	packet->reserved = 0;
+	packet->credits_requested = cpu_to_le16(info->send_credit_target);
+	packet->preferred_send_size = cpu_to_le32(info->max_send_size);
+	packet->max_receive_size = cpu_to_le32(info->max_receive_size);
+	packet->max_fragmented_size =
+		cpu_to_le32(info->max_fragmented_recv_size);
+
+	request->num_sge = 1;
+	request->sge[0].addr = ib_dma_map_single(
+				info->id->device, (void *)packet,
+				sizeof(*packet), DMA_TO_DEVICE);
+	if (ib_dma_mapping_error(info->id->device, request->sge[0].addr)) {
+		rc = -EIO;
+		goto dma_mapping_failed;
+	}
+
+	request->sge[0].length = sizeof(*packet);
+	request->sge[0].lkey = info->pd->local_dma_lkey;
+
+	ib_dma_sync_single_for_device(
+		info->id->device, request->sge[0].addr,
+		request->sge[0].length, DMA_TO_DEVICE);
+
+	request->cqe.done = send_done;
+
+	send_wr.next = NULL;
+	send_wr.wr_cqe = &request->cqe;
+	send_wr.sg_list = request->sge;
+	send_wr.num_sge = request->num_sge;
+	send_wr.opcode = IB_WR_SEND;
+	send_wr.send_flags = IB_SEND_SIGNALED;
+
+	log_rdma_send("sge addr=%llx length=%x lkey=%x\n",
+		request->sge[0].addr,
+		request->sge[0].length, request->sge[0].lkey);
+
+	request->has_payload = false;
+	atomic_inc(&info->send_pending);
+	rc = ib_post_send(info->id->qp, &send_wr, &send_wr_fail);
+	if (!rc)
+		return 0;
+
+	/* if we reach here, post send failed */
+	log_rdma_send("ib_post_send failed rc=%d\n", rc);
+	atomic_dec(&info->send_pending);
+	ib_dma_unmap_single(info->id->device, request->sge[0].addr,
+		request->sge[0].length, DMA_TO_DEVICE);
+
+dma_mapping_failed:
+	mempool_free(request, info->request_mempool);
+	return rc;
+}
+
+/*
+ * Extend the credits to remote peer
+ * This implements [MS-SMBD] 3.1.5.9
+ * The idea is that we should extend credits to remote peer as quickly as
+ * it's allowed, to maintain data flow. We allocate as much receive
+ * buffer as possible, and extend the receive credits to remote peer
+ * return value: the new credtis being granted.
+ */
+static int manage_credits_prior_sending(struct smbd_connection *info)
+{
+	int ret = 0;
+	struct smbd_response *response;
+	int rc;
+
+	if (info->receive_credit_target > atomic_read(&info->receive_credits)) {
+		while (true) {
+			response = get_receive_buffer(info);
+			if (!response)
+				break;
+
+			response->type = SMBD_TRANSFER_DATA;
+			response->first_segment = false;
+			rc = smbd_post_recv(info, response);
+			if (rc) {
+				log_rdma_recv("post_recv failed rc=%d\n", rc);
+				put_receive_buffer(info, response);
+				break;
+			}
+
+			ret++;
+		}
+	}
+
+	atomic_add(ret, &info->receive_credits);
+	log_transport_credit(info);
+
+	if (ret)
+		info->send_immediate = false;
+
+	return ret;
+}
+
+/*
+ * Check if we need to send a KEEP_ALIVE message
+ * The idle connection timer triggers a KEEP_ALIVE message when expires
+ * SMB_DIRECT_RESPONSE_REQUESTED is set in the message flag to have peer send
+ * back a response.
+ * return value:
+ * 1 if SMB_DIRECT_RESPONSE_REQUESTED needs to be set
+ * 0: otherwise
+ */
+static int manage_keep_alive_before_sending(struct smbd_connection *info)
+{
+	if (info->keep_alive_requested == KEEP_ALIVE_PENDING) {
+		info->keep_alive_requested = KEEP_ALIVE_SENT;
+		return 1;
+	}
+	return 0;
+}
+
+/*
+ * Build and prepare the SMBD packet header
+ * This function waits for avaialbe send credits and build a SMBD packet
+ * header. The caller then optional append payload to the packet after
+ * the header
+ * intput values
+ * size: the size of the payload
+ * remaining_data_length: remaining data to send if this is part of a
+ * fragmented packet
+ * output values
+ * request_out: the request allocated from this function
+ * return values: 0 on success, otherwise actual error code returned
+ */
+static int smbd_create_header(struct smbd_connection *info,
+		int size, int remaining_data_length,
+		struct smbd_request **request_out)
+{
+	struct smbd_request *request;
+	struct smbd_data_transfer *packet;
+	int header_length;
+	int rc;
+
+	if (info->transport_status != SMBD_CONNECTED) {
+		log_outgoing("disconnected not sending\n");
+		return -ENOENT;
+	}
+
+	/* Wait for send credits. A SMBD packet needs one credit */
+	rc = wait_event_interruptible(info->wait_send_queue,
+		atomic_read(&info->send_credits) > 0);
+	if (rc)
+		return rc;
+	atomic_dec(&info->send_credits);
+
+	request = mempool_alloc(info->request_mempool, GFP_KERNEL);
+	if (!request) {
+		rc = -ENOMEM;
+		goto err;
+	}
+
+	request->info = info;
+
+	/* Fill in the packet header */
+	packet = smbd_request_payload(request);
+	packet->credits_requested = cpu_to_le16(info->send_credit_target);
+	packet->credits_granted =
+		cpu_to_le16(manage_credits_prior_sending(info));
+
+	packet->flags = 0;
+	if (manage_keep_alive_before_sending(info))
+		packet->flags |= cpu_to_le16(SMB_DIRECT_RESPONSE_REQUESTED);
+
+	packet->reserved = 0;
+	if (!size)
+		packet->data_offset = 0;
+	else
+		packet->data_offset = cpu_to_le32(24);
+	packet->data_length = cpu_to_le32(size);
+	packet->remaining_data_length = cpu_to_le32(remaining_data_length);
+	packet->padding = 0;
+
+	log_outgoing("credits_requested=%d credits_granted=%d data_offset=%d "
+		     "data_length=%d remaining_data_length=%d\n",
+		le16_to_cpu(packet->credits_requested),
+		le16_to_cpu(packet->credits_granted),
+		le32_to_cpu(packet->data_offset),
+		le32_to_cpu(packet->data_length),
+		le32_to_cpu(packet->remaining_data_length));
+
+	/* Map the packet to DMA */
+	header_length = sizeof(struct smbd_data_transfer);
+	/* If this is a packet without payload, don't send padding */
+	if (!size)
+		header_length = offsetof(struct smbd_data_transfer, padding);
+
+	request->num_sge = 1;
+	request->sge[0].addr = ib_dma_map_single(info->id->device,
+						 (void *)packet,
+						 header_length,
+						 DMA_BIDIRECTIONAL);
+	if (ib_dma_mapping_error(info->id->device, request->sge[0].addr)) {
+		mempool_free(request, info->request_mempool);
+		rc = -EIO;
+		goto err;
+	}
+
+	request->sge[0].length = header_length;
+	request->sge[0].lkey = info->pd->local_dma_lkey;
+
+	*request_out = request;
+	return 0;
+
+err:
+	atomic_inc(&info->send_credits);
+	return rc;
+}
+
+static void smbd_destroy_header(struct smbd_connection *info,
+		struct smbd_request *request)
+{
+
+	ib_dma_unmap_single(info->id->device,
+			    request->sge[0].addr,
+			    request->sge[0].length,
+			    DMA_TO_DEVICE);
+	mempool_free(request, info->request_mempool);
+	atomic_inc(&info->send_credits);
+}
+
+/* Post the send request */
+static int smbd_post_send(struct smbd_connection *info,
+		struct smbd_request *request, bool has_payload)
+{
+	struct ib_send_wr send_wr, *send_wr_fail;
+	int rc, i;
+
+	for (i = 0; i < request->num_sge; i++) {
+		log_rdma_send("rdma_request sge[%d] addr=%llu legnth=%u\n",
+			i, request->sge[0].addr, request->sge[0].length);
+		ib_dma_sync_single_for_device(
+			info->id->device,
+			request->sge[i].addr,
+			request->sge[i].length,
+			DMA_TO_DEVICE);
+	}
+
+	request->cqe.done = send_done;
+
+	send_wr.next = NULL;
+	send_wr.wr_cqe = &request->cqe;
+	send_wr.sg_list = request->sge;
+	send_wr.num_sge = request->num_sge;
+	send_wr.opcode = IB_WR_SEND;
+	send_wr.send_flags = IB_SEND_SIGNALED;
+
+	if (has_payload) {
+		request->has_payload = true;
+		atomic_inc(&info->send_payload_pending);
+	} else {
+		request->has_payload = false;
+		atomic_inc(&info->send_pending);
+	}
+
+	rc = ib_post_send(info->id->qp, &send_wr, &send_wr_fail);
+	if (rc) {
+		log_rdma_send("ib_post_send failed rc=%d\n", rc);
+		if (has_payload) {
+			if (atomic_dec_and_test(&info->send_payload_pending))
+				wake_up(&info->wait_send_payload_pending);
+		} else {
+			if (atomic_dec_and_test(&info->send_pending))
+				wake_up(&info->wait_send_pending);
+		}
+	} else
+		/* Reset timer for idle connection after packet is sent */
+		mod_delayed_work(info->workqueue, &info->idle_timer_work,
+			info->keep_alive_interval*HZ);
+
+	return rc;
+}
+
+/*
+ * Send a page
+ * page: the page to send
+ * offset: offset in the page to send
+ * size: length in the page to send
+ * remaining_data_length: remaining data to send in this payload
+ */
+static int smbd_post_send_page(struct smbd_connection *info, struct page *page,
+		unsigned long offset, size_t size, int remaining_data_length)
+{
+	struct smbd_request *request;
+	int rc;
+
+	rc = smbd_create_header(info, size, remaining_data_length, &request);
+	if (rc)
+		return rc;
+
+	/* Add payload to packet */
+	request->num_sge++;
+	request->sge[1].addr = ib_dma_map_page(info->id->device, page,
+					       offset, size, DMA_BIDIRECTIONAL);
+	if (ib_dma_mapping_error(info->id->device, request->sge[1].addr)) {
+		smbd_destroy_header(info, request);
+		return -EIO;
+	}
+	request->sge[1].length = size;
+	request->sge[1].lkey = info->pd->local_dma_lkey;
+
+	rc = smbd_post_send(info, request, true);
+	if (rc) {
+		ib_dma_unmap_single(info->id->device,
+			    request->sge[1].addr,
+			    request->sge[1].length,
+			    DMA_TO_DEVICE);
+		smbd_destroy_header(info, request);
+
+	}
+	return rc;
+}
+
+/*
+ * Send an empty message
+ * Empty message is used to extend credits to peer to for keep live
+ * while there is no upper layer payload to send at the time
+ */
+static int smbd_post_send_empty(struct smbd_connection *info)
+{
+	struct smbd_request *request;
+	int rc;
+
+	rc = smbd_create_header(info, 0, 0, &request);
+	if (rc)
+		return rc;
+
+	info->count_send_empty++;
+	rc = smbd_post_send(info, request, false);
+	if (rc)
+		smbd_destroy_header(info, request);
+
+	return rc;
+}
+
+/*
+ * Send a data buffer
+ * iov: the iov array describing the data buffers
+ * n_vec: number of iov array
+ * remaining_data_length: remaining data to send following this packet
+ * in segmented SMBD packet
+ */
+static int smbd_post_send_data(
+	struct smbd_connection *info, struct kvec *iov, int n_vec,
+	int remaining_data_length)
+{
+	struct smbd_request *request;
+	int rc, i;
+	u32 data_length = 0;
+
+	for (i = 0; i < n_vec; i++)
+		data_length += iov[i].iov_len;
+	rc = smbd_create_header(
+		info, data_length, remaining_data_length, &request);
+	if (rc)
+		return rc;
+
+	for (i = 0; i < n_vec; i++) {
+		request->sge[i+1].addr =
+			ib_dma_map_single(info->id->device, iov[i].iov_base,
+				iov[i].iov_len, DMA_BIDIRECTIONAL);
+		if (ib_dma_mapping_error(
+				info->id->device, request->sge[i+1].addr)) {
+			rc = -EIO;
+			request->sge[i+1].addr = 0;
+			goto dma_mapping_failure;
+		}
+		request->sge[i+1].length = iov[i].iov_len;
+		request->sge[i+1].lkey = info->pd->local_dma_lkey;
+		request->num_sge++;
+	}
+
+	rc = smbd_post_send(info, request, true);
+	if (!rc)
+		return 0;
+
+dma_mapping_failure:
+	for (i = 1; i < request->num_sge; i++)
+		if (request->sge[i].addr)
+			ib_dma_unmap_single(info->id->device,
+					    request->sge[i].addr,
+					    request->sge[i].length,
+					    DMA_TO_DEVICE);
+	smbd_destroy_header(info, request);
+	return rc;
+}
+
+/*
+ * Post a receive request to the transport
+ * The remote peer can only send data when a receive request is posted
+ * The interaction is controlled by send/receive credit system
+ */
+static int smbd_post_recv(
+		struct smbd_connection *info, struct smbd_response *response)
+{
+	struct ib_recv_wr recv_wr, *recv_wr_fail = NULL;
+	int rc = -EIO;
+
+	response->sge.addr = ib_dma_map_single(
+				info->id->device, response->packet,
+				info->max_receive_size, DMA_FROM_DEVICE);
+	if (ib_dma_mapping_error(info->id->device, response->sge.addr))
+		return rc;
+
+	response->sge.length = info->max_receive_size;
+	response->sge.lkey = info->pd->local_dma_lkey;
+
+	response->cqe.done = recv_done;
+
+	recv_wr.wr_cqe = &response->cqe;
+	recv_wr.next = NULL;
+	recv_wr.sg_list = &response->sge;
+	recv_wr.num_sge = 1;
+
+	atomic_inc(&info->recv_pending);
+	rc = ib_post_recv(info->id->qp, &recv_wr, &recv_wr_fail);
+	if (rc) {
+		ib_dma_unmap_single(info->id->device, response->sge.addr,
+				    response->sge.length, DMA_FROM_DEVICE);
+
+		log_rdma_recv("ib_post_recv failed rc=%d\n", rc);
+		atomic_dec(&info->recv_pending);
+	}
+
+	return rc;
+}
+
+/* Perform SMBD negotiate according to [MS-SMBD] 3.1.5.2 */
+static int smbd_negotiate(struct smbd_connection *info)
+{
+	int rc;
+	struct smbd_response *response = get_receive_buffer(info);
+
+	response->type = SMBD_NEGOTIATE_RESP;
+	rc = smbd_post_recv(info, response);
+	log_rdma_event("smbd_post_recv rc=%d iov.addr=%llx iov.length=%x "
+		       "iov.lkey=%x\n",
+		rc, response->sge.addr,
+		response->sge.length, response->sge.lkey);
+	if (rc)
+		return rc;
+
+	init_completion(&info->negotiate_completion);
+	info->negotiate_done = false;
+	rc = smbd_post_send_negotiate_req(info);
+	if (rc)
+		return rc;
+
+	rc = wait_for_completion_interruptible_timeout(
+		&info->negotiate_completion, SMBD_NEGOTIATE_TIMEOUT * HZ);
+	log_rdma_event("wait_for_completion_timeout rc=%d\n", rc);
+
+	if (info->negotiate_done)
+		return 0;
+
+	if (rc == 0)
+		rc = -ETIMEDOUT;
+	else if (rc == -ERESTARTSYS)
+		rc = -EINTR;
+	else
+		rc = -ENOTCONN;
+
+	return rc;
+}
+
+/*
+ * Implement Connection.FragmentReassemblyBuffer defined in [MS-SMBD] 3.1.1.1
+ * This is a queue for reassembling upper layer payload and present to upper
+ * layer. All the inncoming payload go to the reassembly queue, regardless of
+ * if reassembly is required. The uuper layer code reads from the queue for all
+ * incoming payloads.
+ * Put a received packet to the reassembly queue
+ * response: the packet received
+ * data_length: the size of payload in this packet
+ */
+static void enqueue_reassembly(
+	struct smbd_connection *info,
+	struct smbd_response *response,
+	int data_length)
+{
+	spin_lock(&info->reassembly_queue_lock);
+	list_add_tail(&response->list, &info->reassembly_queue);
+	info->reassembly_data_length += data_length;
+	log_reassembly_queue("info->reassembly_data_length=%d\n",
+			info->reassembly_data_length);
+	info->count_reassembly_queue++;
+	info->count_enqueue_reassembly_queue++;
+	spin_unlock(&info->reassembly_queue_lock);
+}
+
+/*
+ * Get the first entry at the front of reassembly queue
+ * Caller is responsible for locking
+ * return value: the first entry if any, NULL if queue is empty
+ */
+static struct smbd_response *_get_first_reassembly(struct smbd_connection *info)
+{
+	struct smbd_response *ret = NULL;
+
+	if (!list_empty(&info->reassembly_queue)) {
+		ret = list_first_entry(
+			&info->reassembly_queue,
+			struct smbd_response, list);
+	}
+	return ret;
+}
+
+/*
+ * Get a receive buffer
+ * For each remote send, we need to post a receive. The receive buffers are
+ * pre-allocated in advance.
+ * return value: the receive buffer, NULL if none is available
+ */
+static struct smbd_response *get_receive_buffer(struct smbd_connection *info)
+{
+	struct smbd_response *ret = NULL;
+
+	spin_lock(&info->receive_queue_lock);
+	if (!list_empty(&info->receive_queue)) {
+		ret = list_first_entry(
+			&info->receive_queue,
+			struct smbd_response, list);
+		list_del(&ret->list);
+		info->count_receive_buffer--;
+		info->count_get_receive_buffer++;
+	}
+	spin_unlock(&info->receive_queue_lock);
+
+	return ret;
+}
+
+/*
+ * Return a receive buffer
+ * Upon returning of a receive buffer, we can post new receive and extend
+ * more receive credits to remote peer. This is done immediately after a
+ * receive buffer is returned.
+ */
+static void put_receive_buffer(
+	struct smbd_connection *info, struct smbd_response *response)
+{
+	ib_dma_unmap_single(info->id->device, response->sge.addr,
+		response->sge.length, DMA_FROM_DEVICE);
+
+	spin_lock(&info->receive_queue_lock);
+	list_add_tail(&response->list, &info->receive_queue);
+	info->count_receive_buffer++;
+	info->count_put_receive_buffer++;
+	spin_unlock(&info->receive_queue_lock);
+
+	/* Check if we can post new receive and grant credits to peer */
+	check_and_send_immediate(info);
+}
+
+/* Preallocate all receive buffer on transport establishment */
+static int allocate_receive_buffers(struct smbd_connection *info, int num_buf)
+{
+	int i;
+	struct smbd_response *response;
+
+	INIT_LIST_HEAD(&info->reassembly_queue);
+	spin_lock_init(&info->reassembly_queue_lock);
+	info->reassembly_data_length = 0;
+
+	INIT_LIST_HEAD(&info->receive_queue);
+	spin_lock_init(&info->receive_queue_lock);
+
+	for (i = 0; i < num_buf; i++) {
+		response = mempool_alloc(info->response_mempool, GFP_KERNEL);
+		if (!response)
+			goto allocate_failed;
+
+		response->info = info;
+		list_add_tail(&response->list, &info->receive_queue);
+		info->count_receive_buffer++;
+	}
+
+	return 0;
+
+allocate_failed:
+	while (!list_empty(&info->receive_queue)) {
+		response = list_first_entry(
+				&info->receive_queue,
+				struct smbd_response, list);
+		list_del(&response->list);
+		info->count_receive_buffer--;
+
+		mempool_free(response, info->response_mempool);
+	}
+	return -ENOMEM;
+}
+
+static void destroy_receive_buffers(struct smbd_connection *info)
+{
+	struct smbd_response *response;
+
+	while ((response = get_receive_buffer(info)))
+		mempool_free(response, info->response_mempool);
+}
+
+/*
+ * Check and send an immediate or keep alive packet
+ * The condition to send those packets are defined in [MS-SMBD] 3.1.1.1
+ * Connection.KeepaliveRequested and Connection.SendImmediate
+ * The idea is to extend credits to server as soon as it becomes available
+ */
+static void send_immediate_work(struct work_struct *work)
+{
+	struct smbd_connection *info = container_of(
+					work, struct smbd_connection,
+					send_immediate_work.work);
+
+	if (info->keep_alive_requested == KEEP_ALIVE_PENDING ||
+	    info->send_immediate) {
+		log_keep_alive("send an empty message\n");
+		smbd_post_send_empty(info);
+	}
+}
+
+/* Implement idle connection timer [MS-SMBD] 3.1.6.2 */
+static void idle_connection_timer(struct work_struct *work)
+{
+	struct smbd_connection *info = container_of(
+					work, struct smbd_connection,
+					idle_timer_work.work);
+
+	if (info->keep_alive_requested != KEEP_ALIVE_NONE) {
+		log_keep_alive("error status info->keep_alive_requested=%d\n",
+				info->keep_alive_requested);
+		smbd_disconnect_rdma_connection(info);
+	}
+
+	log_keep_alive("about to send an empty idle message\n");
+	smbd_post_send_empty(info);
+
+	/* Setup the next idle timeout work */
+	queue_delayed_work(info->workqueue, &info->idle_timer_work,
+				info->keep_alive_interval*HZ);
+}
+
+/* Destroy this SMBD connection, called from upper layer */
+void smbd_destroy(struct smbd_connection *info)
+{
+	log_rdma_event("destroying rdma session\n");
+
+	/* Kick off the disconnection process */
+	if (info->transport_status == SMBD_CONNECTED)
+		rdma_disconnect(info->id);
+
+	info->server_info->tcpStatus = CifsExiting;
+
+	log_rdma_event("wait for transport being destroyed\n");
+	wait_event(info->wait_destroy,
+		info->transport_status == SMBD_DESTROYED);
+}
+
+/*
+ * Reconnect this SMBD connection, called from upper layer
+ * return value: 0 on success, or actual error code
+ */
+int smbd_reconnect(struct TCP_Server_Info *server)
+{
+	log_rdma_event("reconnecting rdma session\n");
+
+	/* why reconnect while it is still connected? */
+	if (server->smbd_conn->transport_status == SMBD_CONNECTED) {
+		log_rdma_event("still connected, not reconnecting\n");
+		return -EINVAL;
+	}
+
+	/* wait until the transport is destroyed */
+	wait_event(server->smbd_conn->wait_destroy,
+		server->smbd_conn->transport_status == SMBD_DESTROYED);
+
+	kfree(server->smbd_conn);
+
+	log_rdma_event("creating rdma session\n");
+	server->smbd_conn = smbd_get_connection(
+		server, (struct sockaddr *) &server->dstaddr);
+
+	return server->smbd_conn ? 0 : -ENOENT;
+}
+
+#define MAX_NAME_LEN	80
+static int allocate_caches_and_workqueue(struct smbd_connection *info)
+{
+	char name[MAX_NAME_LEN];
+
+	snprintf(name, MAX_NAME_LEN, "smbd_request_%p", info);
+	info->request_cache =
+		kmem_cache_create(
+			name,
+			sizeof(struct smbd_request) +
+				sizeof(struct smbd_data_transfer),
+			0, SLAB_HWCACHE_ALIGN, NULL);
+	if (!info->request_cache)
+		return -ENOMEM;
+
+	info->request_mempool =
+		mempool_create(info->send_credit_target, mempool_alloc_slab,
+			mempool_free_slab, info->request_cache);
+	if (!info->request_mempool)
+		goto out1;
+
+	snprintf(name, MAX_NAME_LEN, "smbd_response_%p", info);
+	info->response_cache =
+		kmem_cache_create(
+			name,
+			sizeof(struct smbd_response) +
+				info->max_receive_size,
+			0, SLAB_HWCACHE_ALIGN, NULL);
+	if (!info->response_cache)
+		goto out2;
+
+	info->response_mempool =
+		mempool_create(info->receive_credit_max, mempool_alloc_slab,
+		       mempool_free_slab, info->response_cache);
+	if (!info->response_mempool)
+		goto out3;
+
+	snprintf(name, MAX_NAME_LEN, "smbd_%p", info);
+	info->workqueue = create_workqueue(name);
+	if (!info->workqueue)
+		goto out4;
+
+	return 0;
+
+out4:
+	mempool_destroy(info->response_mempool);
+out3:
+	kmem_cache_destroy(info->response_cache);
+out2:
+	mempool_destroy(info->request_mempool);
+out1:
+	kmem_cache_destroy(info->request_cache);
+	return -ENOMEM;
+}
+
+/* Create a SMBD connection, called by upper layer */
+struct smbd_connection *smbd_get_connection(
+	struct TCP_Server_Info *server, struct sockaddr *dstaddr)
+{
+	int rc;
+	struct smbd_connection *info;
+	struct rdma_conn_param conn_param;
+	struct ib_qp_init_attr qp_attr;
+	struct sockaddr_in *addr_in = (struct sockaddr_in *) dstaddr;
+	int port;
+
+	info = kzalloc(sizeof(struct smbd_connection), GFP_KERNEL);
+	if (!info)
+		return NULL;
+
+	info->server_info = server;
+	info->transport_status = SMBD_CONNECTING;
+
+	port = SMB_PORT;
+try_another_port:
+	rc = smbd_ia_open(info, dstaddr, port);
+	if (rc) {
+		log_rdma_event("smbd_ia_open rc=%d\n", rc);
+		goto out1;
+	}
+
+	if (send_credit_target > info->id->device->attrs.max_cqe ||
+	    send_credit_target > info->id->device->attrs.max_qp_wr) {
+		log_rdma_event("consider lowering send_credit_target = %d. "
+			"Possible CQE overrun, device "
+			"reporting max_cpe %d max_qp_wr %d\n",
+			send_credit_target,
+			info->id->device->attrs.max_cqe,
+			info->id->device->attrs.max_qp_wr);
+		goto out2;
+	}
+
+	if (receive_credit_max > info->id->device->attrs.max_cqe ||
+	    receive_credit_max > info->id->device->attrs.max_qp_wr) {
+		log_rdma_event("consider lowering receive_credit_max = %d. "
+			"Possible CQE overrun, device "
+			"reporting max_cpe %d max_qp_wr %d\n",
+			receive_credit_max,
+			info->id->device->attrs.max_cqe,
+			info->id->device->attrs.max_qp_wr);
+		goto out2;
+	}
+
+	info->receive_credit_max = receive_credit_max;
+	info->send_credit_target = send_credit_target;
+	info->max_send_size = max_send_size;
+	info->max_fragmented_recv_size = max_fragmented_recv_size;
+	info->max_receive_size = max_receive_size;
+	info->keep_alive_interval = keep_alive_interval;
+
+	max_send_sge = min_t(int, max_send_sge,
+		info->id->device->attrs.max_sge);
+	max_recv_sge = min_t(int, max_recv_sge,
+		info->id->device->attrs.max_sge_rd);
+
+	info->send_cq = ib_alloc_cq(info->id->device, info,
+			info->send_credit_target, 0, IB_POLL_WORKQUEUE);
+	if (IS_ERR(info->send_cq))
+		goto out2;
+
+	info->recv_cq = ib_alloc_cq(info->id->device, info,
+			info->receive_credit_max, 0, IB_POLL_WORKQUEUE);
+	if (IS_ERR(info->recv_cq))
+		goto out2;
+
+	memset(&qp_attr, 0, sizeof(qp_attr));
+	qp_attr.event_handler = smbd_qp_async_error_upcall;
+	qp_attr.qp_context = info;
+	qp_attr.cap.max_send_wr = info->send_credit_target;
+	qp_attr.cap.max_recv_wr = info->receive_credit_max;
+	qp_attr.cap.max_send_sge = max_send_sge;
+	qp_attr.cap.max_recv_sge = max_recv_sge;
+	qp_attr.cap.max_inline_data = 0;
+	qp_attr.sq_sig_type = IB_SIGNAL_REQ_WR;
+	qp_attr.qp_type = IB_QPT_RC;
+	qp_attr.send_cq = info->send_cq;
+	qp_attr.recv_cq = info->recv_cq;
+	qp_attr.port_num = ~0;
+
+	rc = rdma_create_qp(info->id, info->pd, &qp_attr);
+	if (rc) {
+		log_rdma_event("rdma_create_qp failed %i\n", rc);
+		rc = -ENETUNREACH;
+		goto out2;
+	}
+
+	memset(&conn_param, 0, sizeof(conn_param));
+	conn_param.private_data = NULL;
+	conn_param.private_data_len = 0;
+	conn_param.initiator_depth = 0;
+
+	conn_param.responder_resources =
+		info->id->device->attrs.max_qp_rd_atom
+			< SMBD_CM_RESPONDER_RESOURCES ?
+		info->id->device->attrs.max_qp_rd_atom :
+		SMBD_CM_RESPONDER_RESOURCES;
+	info->responder_resources = conn_param.responder_resources;
+	log_rdma_mr("responder_resources=%d\n", info->responder_resources);
+
+	conn_param.retry_count = SMBD_CM_RETRY;
+	conn_param.rnr_retry_count = SMBD_CM_RNR_RETRY;
+	conn_param.flow_control = 0;
+	init_waitqueue_head(&info->conn_wait);
+	init_waitqueue_head(&info->wait_destroy);
+
+	log_rdma_event("connecting to IP %pI4 port %d\n",
+		&addr_in->sin_addr, port);
+
+	rc = rdma_connect(info->id, &conn_param);
+	if (rc) {
+		log_rdma_event("rdma_connect() failed with %i\n", rc);
+		goto out2;
+	}
+
+	wait_event_interruptible(
+		info->conn_wait, info->transport_status == SMBD_CONNECTED);
+	if (info->connect_state != RDMA_CM_EVENT_ESTABLISHED)
+		goto out2;
+
+	log_rdma_event("rdma_connect connected\n");
+
+	rc = allocate_caches_and_workqueue(info);
+	if (rc) {
+		log_rdma_event("cache allocation failed\n");
+		goto out2;
+	}
+
+	rc = allocate_receive_buffers(info, info->receive_credit_max);
+	if (rc) {
+		log_rdma_event("failed to allocate receive buffers\n");
+		goto out2;
+	}
+
+	init_waitqueue_head(&info->wait_send_queue);
+	init_waitqueue_head(&info->wait_reassembly_queue);
+
+	INIT_DELAYED_WORK(&info->idle_timer_work, idle_connection_timer);
+	INIT_DELAYED_WORK(&info->send_immediate_work, send_immediate_work);
+	queue_delayed_work(info->workqueue, &info->idle_timer_work,
+		info->keep_alive_interval*HZ);
+
+	init_waitqueue_head(&info->wait_send_pending);
+	atomic_set(&info->send_pending, 0);
+
+	init_waitqueue_head(&info->wait_send_payload_pending);
+	atomic_set(&info->send_payload_pending, 0);
+
+	init_waitqueue_head(&info->wait_recv_pending);
+	atomic_set(&info->recv_pending, 0);
+
+	init_waitqueue_head(&info->wait_read_pending);
+	atomic_set(&info->read_pending, 0);
+
+	INIT_WORK(&info->disconnect_work, smbd_disconnect_rdma_work);
+	INIT_WORK(&info->destroy_work, smbd_destroy_rdma_work);
+
+	rc = smbd_negotiate(info);
+	if (rc) {
+		log_rdma_event("smbd_negotiate rc=%d\n", rc);
+		goto negotiation_failed;
+	}
+
+	rc = allocate_mr_list(info);
+	if (rc) {
+		log_rdma_mr("memory registration allocation failed\n");
+		goto negotiation_failed;
+	}
+
+	return info;
+
+negotiation_failed:
+	smbd_destroy(info);
+
+out2:
+	rdma_destroy_id(info->id);
+	/* try port SMBD_PORT if SMB_PORT doesn't work */
+	if (port == SMB_PORT) {
+		port = SMBD_PORT;
+		goto try_another_port;
+	}
+
+out1:
+	kfree(info);
+	return NULL;
+}
+
+/*
+ * Receive a page from receive reassembly queue
+ * page: the page to read data into
+ * to_read: the length of data to read
+ * return value: actual data read
+ */
+int smbd_recv_page(struct smbd_connection *info,
+		struct page *page, unsigned int to_read)
+{
+	int ret;
+	char *to_address;
+
+	/* make sure we have the page ready for read */
+	ret = wait_event_interruptible(
+		info->wait_reassembly_queue,
+		info->reassembly_data_length >= to_read ||
+			info->transport_status != SMBD_CONNECTED);
+	if (ret)
+		return 0;
+
+	/* now we can read from reassembly queue and not sleep */
+	to_address = kmap_atomic(page);
+
+	log_read("reading from page=%p address=%p to_read=%d\n",
+		page, to_address, to_read);
+
+	ret = smbd_recv(info, to_address, to_read);
+	kunmap_atomic(to_address);
+
+	return ret;
+}
+
+/*
+ * Receive data from receive reassembly queue
+ * All the incoming data packets are placed in reassembly queue
+ * buf: the buffer to read data into
+ * size: the length of data to read
+ * return value: actual data read
+ * Note: this implementation copies the data from reassebmly queue to receive
+ * buffers used by upper layer. This is not the optimal code path. A better way
+ * to do it is to not have upper layer allocate its receive buffers but rather
+ * borrow the buffer from reassembly queue, and return it after data is
+ * consumed. But this will require more changes to upper layer code, and also
+ * need to consider packet boundaries while they still being reassembled.
+ */
+int smbd_recv(struct smbd_connection *info, char *buf, unsigned int size)
+{
+	struct smbd_response *response;
+	struct smbd_data_transfer *data_transfer;
+	int to_copy, to_read, data_read, offset;
+	u32 data_length, remaining_data_length, data_offset;
+	int rc;
+
+again:
+	/* the transport is disconnected? */
+	if (info->transport_status != SMBD_CONNECTED) {
+		log_read("disconnected\n");
+
+		/*
+		 * FIXME If upper layer code is reading SMB packet length
+		 * return 0 to indicate transport is disconnected and
+		 * trigger a reconnect.
+		 */
+		return 0;
+	}
+
+	/*
+	 * No need to hold the reassembly queue lock all the time as we are
+	 * the only one reading from the front of the queue. The transport
+	 * may add more entries to the back of the queeu at the same time
+	 */
+	log_read("size=%d info->reassembly_data_length=%d\n", size,
+		info->reassembly_data_length);
+	if (info->reassembly_data_length >= size) {
+		atomic_inc(&info->read_pending);
+		data_read = 0;
+		to_read = size;
+		offset = info->first_entry_offset;
+		while (data_read < size) {
+			spin_lock(&info->reassembly_queue_lock);
+			response = _get_first_reassembly(info);
+			spin_unlock(&info->reassembly_queue_lock);
+			data_transfer = smbd_response_payload(response);
+
+			data_length = le32_to_cpu(data_transfer->data_length);
+			remaining_data_length =
+				le32_to_cpu(
+					data_transfer->remaining_data_length);
+			data_offset = le32_to_cpu(data_transfer->data_offset);
+
+			/*
+			 * The upper layer expects RFC1002 length at the
+			 * beginning of the payload. Return it to indicate
+			 * the total length of the packet. This minimize the
+			 * change to upper layer packet processing logic. This
+			 * will be eventually remove when an intermediate
+			 * transport layer is added
+			 */
+			if (response->first_segment && size == 4) {
+				unsigned int rfc1002_len =
+					data_length + remaining_data_length;
+				*((__be32 *)buf) = cpu_to_be32(rfc1002_len);
+				data_read = 4;
+				response->first_segment = false;
+				log_read("returning rfc1002 length %d\n",
+					rfc1002_len);
+				goto read_rfc1002_done;
+			}
+
+			to_copy = min_t(int, data_length - offset, to_read);
+			memcpy(
+				buf + data_read,
+				(char *)data_transfer + data_offset + offset,
+				to_copy);
+
+			/* move on to the next buffer? */
+			if (to_copy == data_length - offset) {
+				spin_lock(&info->reassembly_queue_lock);
+				list_del(&response->list);
+				spin_unlock(&info->reassembly_queue_lock);
+
+				info->count_reassembly_queue--;
+				info->count_dequeue_reassembly_queue++;
+				put_receive_buffer(info, response);
+				offset = 0;
+				log_read("put_receive_buffer offset=0\n");
+			} else
+				offset += to_copy;
+
+			to_read -= to_copy;
+			data_read += to_copy;
+
+			log_read("_get_first_reassembly memcpy %d bytes "
+				"data_transfer_length-offset=%d after that "
+				"to_read=%d data_read=%d offset=%d\n",
+				to_copy, data_length - offset,
+				to_read, data_read, offset);
+		}
+
+		spin_lock(&info->reassembly_queue_lock);
+		info->reassembly_data_length -= data_read;
+		spin_unlock(&info->reassembly_queue_lock);
+
+		info->first_entry_offset = offset;
+		log_read("returning to thread data_read=%d "
+			"reassembly_data_length=%d first_entry_offset=%d\n",
+			data_read, info->reassembly_data_length,
+			info->first_entry_offset);
+read_rfc1002_done:
+		if (atomic_dec_and_test(&info->read_pending))
+			wake_up(&info->wait_read_pending);
+		return data_read;
+	}
+
+	log_read("wait_event on more data\n");
+	rc = wait_event_interruptible(
+		info->wait_reassembly_queue,
+		info->reassembly_data_length >= size ||
+			info->transport_status != SMBD_CONNECTED);
+	/* Don't return any data if interrupted */
+	if (rc)
+		return 0;
+
+	goto again;
+}
+
+/*
+ * Send data to transport
+ * Each rqst is transported as a SMBDirect payload
+ * rqst: the data to write
+ * return value: 0 if successfully write, otherwise error code
+ */
+int smbd_send(struct smbd_connection *info, struct smb_rqst *rqst)
+{
+	struct kvec vec;
+	int nvecs;
+	int size;
+	int buflen = 0, remaining_data_length;
+	int start, i, j;
+	int max_iov_size =
+		info->max_send_size - sizeof(struct smbd_data_transfer);
+	struct kvec iov[SMBDIRECT_MAX_SGE];
+	int rc;
+
+	if (info->transport_status != SMBD_CONNECTED) {
+		log_write("disconnected returning -EIO\n");
+		return -EIO;
+	}
+
+	/*
+	 * This usually means a configuration error
+	 * We use RDMA read/write for packet size > rdma_readwrite_threshold
+	 * as long as it's properly configured we should never get into this
+	 * situation
+	 */
+	if (rqst->rq_nvec + rqst->rq_npages > SMBDIRECT_MAX_SGE) {
+		log_write("maximum send segment %x exceeding %x\n",
+			 rqst->rq_nvec + rqst->rq_npages, SMBDIRECT_MAX_SGE);
+		return -EINVAL;
+	}
+
+	/*
+	 * Remove the RFC1002 length defined in MS-SMB2 section 2.1
+	 * It is used only for TCP transport
+	 * In future we may want to add a transport layer under protocol
+	 * layer so this will only be issued to TCP transport
+	 */
+	iov[0].iov_base = (char *)rqst->rq_iov[0].iov_base + 4;
+	iov[0].iov_len = rqst->rq_iov[0].iov_len - 4;
+	buflen += iov[0].iov_len;
+
+	/* total up iov array first */
+	for (i = 1; i < rqst->rq_nvec; i++) {
+		iov[i].iov_base = rqst->rq_iov[i].iov_base;
+		iov[i].iov_len = rqst->rq_iov[i].iov_len;
+		buflen += iov[i].iov_len;
+	}
+
+	/* add in the page array if there is one */
+	if (rqst->rq_npages) {
+		buflen += rqst->rq_pagesz * (rqst->rq_npages - 1);
+		buflen += rqst->rq_tailsz;
+	}
+
+	if (buflen + sizeof(struct smbd_data_transfer) >
+		info->max_fragmented_send_size) {
+		log_write("payload size %d > max size %d\n",
+			buflen, info->max_fragmented_send_size);
+		rc = -EINVAL;
+		goto done;
+	}
+
+	remaining_data_length = buflen;
+
+	log_write("rqst->rq_nvec=%d rqst->rq_npages=%d rq_pagesz=%d "
+		"rq_tailsz=%d buflen=%d\n",
+		rqst->rq_nvec, rqst->rq_npages, rqst->rq_pagesz,
+		rqst->rq_tailsz, buflen);
+
+	start = i = iov[0].iov_len ? 0 : 1;
+	buflen = 0;
+	while (true) {
+		buflen += iov[i].iov_len;
+		if (buflen > max_iov_size) {
+			if (i > start) {
+				remaining_data_length -=
+					(buflen-iov[i].iov_len);
+				log_write("sending iov[] from start=%d "
+					"i=%d nvecs=%d "
+					"remaining_data_length=%d\n",
+					start, i, i-start,
+					remaining_data_length);
+				rc = smbd_post_send_data(
+					info, &iov[start], i-start,
+					remaining_data_length);
+				if (rc)
+					goto done;
+			} else {
+				/* iov[start] is too big, break it */
+				nvecs = (buflen+max_iov_size-1)/max_iov_size;
+				log_write("iov[%d] iov_base=%p buflen=%d"
+					" break to %d vectors\n",
+					start, iov[start].iov_base,
+					buflen, nvecs);
+				for (j = 0; j < nvecs; j++) {
+					vec.iov_base =
+						(char *)iov[start].iov_base +
+						j*max_iov_size;
+					vec.iov_len = max_iov_size;
+					if (j == nvecs-1)
+						vec.iov_len =
+							buflen -
+							max_iov_size*(nvecs-1);
+					remaining_data_length -= vec.iov_len;
+					log_write(
+						"sending vec j=%d iov_base=%p"
+						" iov_len=%lu "
+						"remaining_data_length=%d\n",
+						j, vec.iov_base, vec.iov_len,
+						remaining_data_length);
+					rc = smbd_post_send_data(
+						info, &vec, 1,
+						remaining_data_length);
+					if (rc)
+						goto done;
+				}
+				i++;
+			}
+			start = i;
+			buflen = 0;
+		} else {
+			i++;
+			if (i == rqst->rq_nvec) {
+				/* send out all remaining vecs */
+				remaining_data_length -= buflen;
+				log_write(
+					"sending iov[] from start=%d i=%d "
+					"nvecs=%d remaining_data_length=%d\n",
+					start, i, i-start,
+					remaining_data_length);
+				rc = smbd_post_send_data(info, &iov[start],
+					i-start, remaining_data_length);
+				if (rc)
+					goto done;
+				break;
+			}
+		}
+		log_write("looping i=%d buflen=%d\n", i, buflen);
+	}
+
+	/* now sending pages if there are any */
+	for (i = 0; i < rqst->rq_npages; i++) {
+		buflen = (i == rqst->rq_npages-1) ?
+			rqst->rq_tailsz : rqst->rq_pagesz;
+		nvecs = (buflen + max_iov_size - 1) / max_iov_size;
+		log_write("sending pages buflen=%d nvecs=%d\n",
+			buflen, nvecs);
+		for (j = 0; j < nvecs; j++) {
+			size = max_iov_size;
+			if (j == nvecs-1)
+				size = buflen - j*max_iov_size;
+			remaining_data_length -= size;
+			log_write("sending pages i=%d offset=%d size=%d"
+				" remaining_data_length=%d\n",
+				i, j*max_iov_size, size, remaining_data_length);
+			rc = smbd_post_send_page(
+				info, rqst->rq_pages[i], j*max_iov_size,
+				size, remaining_data_length);
+			if (rc)
+				goto done;
+		}
+	}
+
+done:
+	/*
+	 * As an optimization, we don't wait for individual I/O to finish
+	 * before sending the next one.
+	 * Send them all and wait for pending send count to get to 0
+	 * that means all the I/Os have been out and we are good to return
+	 */
+	wait_event(info->wait_send_payload_pending,
+		atomic_read(&info->send_payload_pending) == 0);
+	return rc;
+}
+
+static void register_mr_done(struct ib_cq *cq, struct ib_wc *wc)
+{
+	if (wc->status)
+		log_rdma_mr("status=%d\n", wc->status);
+}
+
+/*
+ * The work queue function that recovers MRs
+ * We need to call ib_dereg_mr() and ib_alloc_mr() before this MR can be used
+ * again. Both calls are slow, so finish them in a workqueue. This will not
+ * block I/O path.
+ * There is one workqueue that recovers MRs, there is no need to lock as the
+ * I/O requests calling smbd_register_mr will never update the links in the
+ * mr_list.
+ */
+static void smbd_mr_recovery_work(struct work_struct *work)
+{
+	struct smbd_connection *info =
+		container_of(work, struct smbd_connection, mr_recovery_work);
+	struct smbd_mr *smbdirect_mr;
+	int rc;
+
+	list_for_each_entry(smbdirect_mr, &info->mr_list, list) {
+		if (smbdirect_mr->state == MR_INVALIDATED ||
+			smbdirect_mr->state == MR_ERROR) {
+
+			/* recover this MR entry */
+			if (smbdirect_mr->state == MR_INVALIDATED)
+				ib_dma_unmap_sg(
+					info->id->device,
+					smbdirect_mr->sgl,
+					smbdirect_mr->sgl_count,
+					smbdirect_mr->dir);
+
+			rc = ib_dereg_mr(smbdirect_mr->mr);
+			if (rc) {
+				log_rdma_mr("ib_dereg_mr faield rc=%x\n", rc);
+				rdma_disconnect(info->id);
+			}
+
+			smbdirect_mr->mr = ib_alloc_mr(
+				info->pd, info->mr_type, info->max_frmr_depth);
+			if (IS_ERR(smbdirect_mr->mr)) {
+				log_rdma_mr(
+					"ib_alloc_mr failed mr_type=%x "
+					"max_frmr_depth=%x\n",
+					info->mr_type, info->max_frmr_depth);
+				rdma_disconnect(info->id);
+			}
+
+			smbdirect_mr->state = MR_READY;
+			/* smbdirect_mr->state is updated by this function
+			 * and is read and updated by I/O issuing CPUs trying
+			 * to get a MR, the call to atomic_inc_return
+			 * implicates a memory barrier and guarantees this
+			 * value is updated before waking up any calls to
+			 * get_mr() from the I/O issuing CPUs
+			 */
+			if (atomic_inc_return(&info->mr_ready_count) == 1)
+				wake_up_interruptible(&info->wait_mr);
+		}
+	}
+}
+
+static void destroy_mr_list(struct smbd_connection *info)
+{
+	struct smbd_mr *mr, *tmp;
+
+	cancel_work_sync(&info->mr_recovery_work);
+	list_for_each_entry_safe(mr, tmp, &info->mr_list, list) {
+		if (mr->state == MR_INVALIDATED)
+			ib_dma_unmap_sg(info->id->device, mr->sgl,
+				mr->sgl_count, mr->dir);
+		ib_dereg_mr(mr->mr);
+		kfree(mr->sgl);
+		kfree(mr);
+	}
+}
+
+/*
+ * Allocate MRs used for RDMA read/write
+ * The number of MRs will not exceed hardware capability in responder_resources
+ * All MRs are kept in mr_list. The MR can be recovered after it's used
+ * Recovery is done in smbd_mr_recovery_work. The content of list entry changes
+ * as MRs are used and recovered for I/O, but the list links will not change
+ */
+static int allocate_mr_list(struct smbd_connection *info)
+{
+	int i;
+	struct smbd_mr *smbdirect_mr, *tmp;
+
+	INIT_LIST_HEAD(&info->mr_list);
+	init_waitqueue_head(&info->wait_mr);
+	spin_lock_init(&info->mr_list_lock);
+	atomic_set(&info->mr_ready_count, 0);
+	for (i = 0; i < info->responder_resources; i++) {
+		smbdirect_mr = kzalloc(sizeof(*smbdirect_mr), GFP_KERNEL);
+		if (!smbdirect_mr)
+			goto out;
+		smbdirect_mr->mr = ib_alloc_mr(info->pd, info->mr_type,
+					info->max_frmr_depth);
+		if (IS_ERR(smbdirect_mr->mr)) {
+			log_rdma_mr("ib_alloc_mr failed mr_type=%x "
+				"max_frmr_depth=%x\n",
+				info->mr_type, info->max_frmr_depth);
+			goto out;
+		}
+		smbdirect_mr->sgl = kcalloc(
+					info->max_frmr_depth,
+					sizeof(struct scatterlist),
+					GFP_KERNEL);
+		if (!smbdirect_mr->sgl) {
+			log_rdma_mr("failed to allocate sgl\n");
+			ib_dereg_mr(smbdirect_mr->mr);
+			goto out;
+		}
+		smbdirect_mr->state = MR_READY;
+		smbdirect_mr->conn = info;
+
+		list_add_tail(&smbdirect_mr->list, &info->mr_list);
+		atomic_inc(&info->mr_ready_count);
+	}
+	INIT_WORK(&info->mr_recovery_work, smbd_mr_recovery_work);
+	return 0;
+
+out:
+	kfree(smbdirect_mr);
+
+	list_for_each_entry_safe(smbdirect_mr, tmp, &info->mr_list, list) {
+		ib_dereg_mr(smbdirect_mr->mr);
+		kfree(smbdirect_mr->sgl);
+		kfree(smbdirect_mr);
+	}
+	return -ENOMEM;
+}
+
+/*
+ * Get a MR from mr_list. This function waits until there is at least one
+ * MR available in the list. It may access the list while the
+ * smbd_mr_recovery_work is recovering the MR list. This doesn't need a lock
+ * as they never modify the same places. However, there may be several CPUs
+ * issueing I/O trying to get MR at the same time, mr_list_lock is used to
+ * protect this situation.
+ */
+static struct smbd_mr *get_mr(struct smbd_connection *info)
+{
+	struct smbd_mr *ret;
+	int rc;
+again:
+	rc = wait_event_interruptible(info->wait_mr,
+		atomic_read(&info->mr_ready_count) ||
+		info->transport_status != SMBD_CONNECTED);
+	if (rc) {
+		log_rdma_mr("wait_event_interruptible rc=%x\n", rc);
+		return NULL;
+	}
+
+	if (info->transport_status != SMBD_CONNECTED) {
+		log_rdma_mr("info->transport_status=%x\n",
+			info->transport_status);
+		return NULL;
+	}
+
+	spin_lock(&info->mr_list_lock);
+	list_for_each_entry(ret, &info->mr_list, list) {
+		if (ret->state == MR_READY) {
+			ret->state = MR_REGISTERED;
+			atomic_dec(&info->mr_ready_count);
+			spin_unlock(&info->mr_list_lock);
+			return ret;
+		}
+	}
+
+	spin_unlock(&info->mr_list_lock);
+	/*
+	 * It is possible that we can get a MR because other processes may try
+	 * to acquire a MR at the same time. If this is the case, retry it.
+	 */
+	goto again;
+}
+
+/*
+ * Register memory for RDMA read/write
+ * pages[]: the list of pages to register memory with
+ * num_pages: the number of pages to register
+ * tailsz: if non-zero, the bytes to register in the last page
+ * writing: true if this is a RDMA write (SMB read), false for RDMA read
+ * need_invalidate: true if this MR needs to be locally invalidated after I/O
+ * return value: the MR registered, NULL if failed.
+ */
+struct smbd_mr *smbd_register_mr(
+	struct smbd_connection *info, struct page *pages[], int num_pages,
+	int tailsz, bool writing, bool need_invalidate)
+{
+	struct smbd_mr *smbdirect_mr;
+	int rc, i;
+	enum dma_data_direction dir;
+	struct ib_reg_wr *reg_wr;
+	struct ib_send_wr *bad_wr;
+
+	if (num_pages > info->max_frmr_depth) {
+		log_rdma_mr("num_pages=%d max_frmr_depth=%d\n",
+			num_pages, info->max_frmr_depth);
+		return NULL;
+	}
+
+	smbdirect_mr = get_mr(info);
+	if (!smbdirect_mr) {
+		log_rdma_mr("get_mr returning NULL\n");
+		return NULL;
+	}
+	smbdirect_mr->need_invalidate = need_invalidate;
+	smbdirect_mr->sgl_count = num_pages;
+	sg_init_table(smbdirect_mr->sgl, num_pages);
+
+	for (i = 0; i < num_pages - 1; i++)
+		sg_set_page(&smbdirect_mr->sgl[i], pages[i], PAGE_SIZE, 0);
+	sg_set_page(&smbdirect_mr->sgl[i], pages[i],
+		tailsz ? tailsz : PAGE_SIZE, 0);
+
+	dir = writing ? DMA_FROM_DEVICE : DMA_TO_DEVICE;
+	smbdirect_mr->dir = dir;
+	rc = ib_dma_map_sg(info->id->device, smbdirect_mr->sgl, num_pages, dir);
+	if (!rc) {
+		log_rdma_mr("ib_dma_map_sg num_pages=%x dir=%x rc=%x\n",
+			num_pages, dir, rc);
+		goto dma_map_error;
+	}
+
+	rc = ib_map_mr_sg(smbdirect_mr->mr, smbdirect_mr->sgl, num_pages,
+		NULL, PAGE_SIZE);
+	if (rc != num_pages) {
+		log_rdma_mr("ib_map_mr_sg failed rc = %x num_pages = %x\n",
+			rc, num_pages);
+		goto map_mr_error;
+	}
+
+	ib_update_fast_reg_key(smbdirect_mr->mr,
+		ib_inc_rkey(smbdirect_mr->mr->rkey));
+	reg_wr = &smbdirect_mr->wr;
+	reg_wr->wr.opcode = IB_WR_REG_MR;
+	smbdirect_mr->cqe.done = register_mr_done;
+	reg_wr->wr.wr_cqe = &smbdirect_mr->cqe;
+	reg_wr->wr.num_sge = 0;
+	reg_wr->wr.send_flags = IB_SEND_SIGNALED;
+	reg_wr->mr = smbdirect_mr->mr;
+	reg_wr->key = smbdirect_mr->mr->rkey;
+	reg_wr->access = writing ?
+			IB_ACCESS_REMOTE_WRITE | IB_ACCESS_LOCAL_WRITE :
+			IB_ACCESS_REMOTE_READ;
+
+	/*
+	 * There is no need for waiting for complemtion on ib_post_send
+	 * on IB_WR_REG_MR. Hardware enforces a barrier and order of execution
+	 * on the next ib_post_send when we actaully send I/O to remote peer
+	 */
+	rc = ib_post_send(info->id->qp, &reg_wr->wr, &bad_wr);
+	if (!rc)
+		return smbdirect_mr;
+
+	log_rdma_mr("ib_post_send failed rc=%x reg_wr->key=%x\n",
+		rc, reg_wr->key);
+
+	/* If all failed, attempt to recover this MR by setting it MR_ERROR*/
+map_mr_error:
+	ib_dma_unmap_sg(info->id->device, smbdirect_mr->sgl,
+		smbdirect_mr->sgl_count, smbdirect_mr->dir);
+
+dma_map_error:
+	smbdirect_mr->state = MR_ERROR;
+
+	return NULL;
+}
+
+static void local_inv_done(struct ib_cq *cq, struct ib_wc *wc)
+{
+	struct smbd_mr *smbdirect_mr;
+	struct ib_cqe *cqe;
+
+	cqe = wc->wr_cqe;
+	smbdirect_mr = container_of(cqe, struct smbd_mr, cqe);
+	smbdirect_mr->state = MR_INVALIDATED;
+	if (wc->status != IB_WC_SUCCESS) {
+		log_rdma_mr("invalidate failed status=%x\n", wc->status);
+		smbdirect_mr->state = MR_ERROR;
+	}
+	complete(&smbdirect_mr->invalidate_done);
+}
+
+/*
+ * Deregister a MR after I/O is done
+ * This function may wait if remote invalidation is not used
+ * and we have to locally invalidate the buffer to prevent data is being
+ * modified by remote peer after upper layer consumes it
+ */
+int smbd_deregister_mr(struct smbd_mr *smbdirect_mr)
+{
+	struct ib_send_wr *wr, *bad_wr;
+	struct smbd_connection *info = smbdirect_mr->conn;
+	int rc;
+
+	if (info->transport_status != SMBD_CONNECTED)
+		return -ENODEV;
+
+	if (smbdirect_mr->need_invalidate) {
+		/* Need to finish local invalidation before returning */
+		wr = &smbdirect_mr->inv_wr;
+		wr->opcode = IB_WR_LOCAL_INV;
+		smbdirect_mr->cqe.done = local_inv_done;
+		wr->wr_cqe = &smbdirect_mr->cqe;
+		wr->num_sge = 0;
+		wr->ex.invalidate_rkey = smbdirect_mr->mr->rkey;
+		wr->send_flags = IB_SEND_SIGNALED;
+
+		init_completion(&smbdirect_mr->invalidate_done);
+		rc = ib_post_send(info->id->qp, wr, &bad_wr);
+		if (rc) {
+			log_rdma_mr("ib_post_send failed rc=%x\n", rc);
+			rdma_disconnect(info->id);
+			return rc;
+		}
+		wait_for_completion(&smbdirect_mr->invalidate_done);
+	} else
+		/*
+		 * For remote invalidation, just set it to MR_INVALIDATED
+		 * and defer to mr_recovery_work to recover the MR for next use
+		 */
+		smbdirect_mr->state = MR_INVALIDATED;
+
+	/*
+	 * Schedule the work to do MR recovery for future I/Os
+	 * MR recovery is slow and we don't want it to block the current I/O
+	 */
+	schedule_work(&info->mr_recovery_work);
+
+	return 0;
+}
diff --git a/fs/cifs/smbdirect.h b/fs/cifs/smbdirect.h
index 06eeb0b..ec692eb 100644
--- a/fs/cifs/smbdirect.h
+++ b/fs/cifs/smbdirect.h
@@ -16,5 +16,285 @@
 #ifndef _SMBDIRECT_H
 #define _SMBDIRECT_H
 
+#include "cifsglob.h"
+#include <rdma/ib_verbs.h>
+#include <rdma/rdma_cm.h>
+#include <linux/mempool.h>
+
+enum keep_alive_status {
+	KEEP_ALIVE_NONE,
+	KEEP_ALIVE_PENDING,
+	KEEP_ALIVE_SENT,
+};
+
+enum smbd_connection_status {
+	SMBD_CREATED,
+	SMBD_CONNECTING,
+	SMBD_CONNECTED,
+	SMBD_DISCONNECTING,
+	SMBD_DISCONNECTED,
+	SMBD_DESTROYED
+};
+
+/*
+ * The context for the SMBDirect transport
+ * Everything related to the transport is here. It has several logical parts
+ * 1. RDMA related structures
+ * 2. SMBDirect connection parameters
+ * 3. Memory registrations
+ * 4. Receive and reassembly queues for data receive path
+ * 5. mempools for allocating packets
+ */
+struct smbd_connection {
+	struct TCP_Server_Info *server_info;
+	enum smbd_connection_status transport_status;
+
+	/* RDMA related */
+	struct rdma_cm_id *id;
+	struct ib_qp_init_attr qp_attr;
+	struct ib_pd *pd;
+	struct ib_cq *send_cq, *recv_cq;
+	struct ib_device_attr dev_attr;
+	int connect_state;
+	int ri_rc;
+	struct completion ri_done;
+	wait_queue_head_t conn_wait;
+	wait_queue_head_t wait_destroy;
+
+	struct completion negotiate_completion;
+	bool negotiate_done;
+
+	struct work_struct destroy_work;
+	struct work_struct disconnect_work;
+
+	/* Connection parameters defined in [MS-SMBD] 3.1.1.1 */
+	int receive_credit_max;
+	int send_credit_target;
+	int max_send_size;
+	int max_fragmented_recv_size;
+	int max_fragmented_send_size;
+	int max_receive_size;
+	int keep_alive_interval;
+	int max_readwrite_size;
+	enum keep_alive_status keep_alive_requested;
+	int protocol;
+	atomic_t send_credits;
+	atomic_t receive_credits;
+	int receive_credit_target;
+	int fragment_reassembly_remaining;
+
+	/* Memory registrations */
+	/* Maximum number of RDMA read/write outstanding on this connection */
+	int responder_resources;
+	/* Maximum number of SGEs in a RDMA write/read */
+	int max_frmr_depth;
+	/*
+	 * If payload is less than or equal to the threshold,
+	 * use RDMA send/recv to send upper layer I/O.
+	 * If payload is more than the threshold,
+	 * use RDMA read/write through memory registration for I/O.
+	 */
+	int rdma_readwrite_threshold;
+	enum ib_mr_type mr_type;
+	struct list_head mr_list;
+	spinlock_t mr_list_lock;
+	/* The number of available MRs ready for memory registration */
+	atomic_t mr_ready_count;
+	wait_queue_head_t wait_mr;
+	struct work_struct mr_recovery_work;
+
+	/* Activity accoutning */
+	atomic_t send_pending;
+	wait_queue_head_t wait_send_pending;
+	atomic_t send_payload_pending;
+	wait_queue_head_t wait_send_payload_pending;
+	atomic_t recv_pending;
+	wait_queue_head_t wait_recv_pending;
+	atomic_t read_pending;
+	wait_queue_head_t wait_read_pending;
+
+	/* Receive queue */
+	struct list_head receive_queue;
+	spinlock_t receive_queue_lock;
+
+	/* Reassembly queue */
+	struct list_head reassembly_queue;
+	spinlock_t reassembly_queue_lock;
+	wait_queue_head_t wait_reassembly_queue;
+
+	/* total data length of reassembly queue */
+	int reassembly_data_length;
+	/* the offset to first buffer in reassembly queue */
+	int first_entry_offset;
+
+	bool send_immediate;
+
+	wait_queue_head_t wait_send_queue;
+
+	/*
+	 * Indicate if we have received a full packet on the connection
+	 * This is used to identify the first SMBD packet of a assembled
+	 * payload (SMB packet) in reassembly queue so we can return a
+	 * RFC1002 length to upper layer to indicate the length of the SMB
+	 * packet received
+	 */
+	bool full_packet_received;
+
+	struct workqueue_struct *workqueue;
+	struct delayed_work idle_timer_work;
+	struct delayed_work send_immediate_work;
+
+	/* Memory pool for preallocating buffers */
+	/* request pool for RDMA send */
+	struct kmem_cache *request_cache;
+	mempool_t *request_mempool;
+
+	/* response pool for RDMA receive */
+	struct kmem_cache *response_cache;
+	mempool_t *response_mempool;
+
+	/* for debug purposes */
+	unsigned int count_receive_buffer;
+	unsigned int count_get_receive_buffer;
+	unsigned int count_put_receive_buffer;
+	unsigned int count_reassembly_queue;
+	unsigned int count_enqueue_reassembly_queue;
+	unsigned int count_dequeue_reassembly_queue;
+	unsigned int count_send_empty;
+};
+
+enum smbd_message_type {
+	SMBD_NEGOTIATE_RESP,
+	SMBD_TRANSFER_DATA,
+};
+
+#define SMB_DIRECT_RESPONSE_REQUESTED 0x0001
+
+/* SMBD negotiation request packet [MS-SMBD] 2.2.1 */
+struct smbd_negotiate_req {
+	__le16 min_version;
+	__le16 max_version;
+	__le16 reserved;
+	__le16 credits_requested;
+	__le32 preferred_send_size;
+	__le32 max_receive_size;
+	__le32 max_fragmented_size;
+} __packed;
+
+/* SMBD negotiation response packet [MS-SMBD] 2.2.2 */
+struct smbd_negotiate_resp {
+	__le16 min_version;
+	__le16 max_version;
+	__le16 negotiated_version;
+	__le16 reserved;
+	__le16 credits_requested;
+	__le16 credits_granted;
+	__le32 status;
+	__le32 max_readwrite_size;
+	__le32 preferred_send_size;
+	__le32 max_receive_size;
+	__le32 max_fragmented_size;
+} __packed;
+
+/* SMBD data transfer packet with payload [MS-SMBD] 2.2.3 */
+struct smbd_data_transfer {
+	__le16 credits_requested;
+	__le16 credits_granted;
+	__le16 flags;
+	__le16 reserved;
+	__le32 remaining_data_length;
+	__le32 data_offset;
+	__le32 data_length;
+	__le32 padding;
+	__u8 buffer[];
+} __packed;
+
+/* The packet fields for a registered RDMA buffer */
+struct smbd_buffer_descriptor_v1 {
+	__le64 offset;
+	__le32 token;
+	__le32 length;
+} __packed;
+
 #define SMBDIRECT_MAX_SGE	16
+/* The context for a SMBD request */
+struct smbd_request {
+	struct smbd_connection *info;
+	struct ib_cqe cqe;
+
+	/* true if this request carries upper layer payload */
+	bool has_payload;
+
+	/* the SGE entries for this packet */
+	struct ib_sge sge[SMBDIRECT_MAX_SGE];
+	int num_sge;
+
+	/* SMBD packet header follows this structure */
+	u8 packet[];
+};
+
+/* The context for a SMBD response */
+struct smbd_response {
+	struct smbd_connection *info;
+	struct ib_cqe cqe;
+	struct ib_sge sge;
+
+	enum smbd_message_type type;
+
+	/* Link to receive queue or reassembly queue */
+	struct list_head list;
+
+	/* Indicate if this is the 1st packet of a payload */
+	bool first_segment;
+
+	/* SMBD packet header and payload follows this structure */
+	u8 packet[];
+};
+
+/* Create a SMBDirect session */
+struct smbd_connection *smbd_get_connection(
+	struct TCP_Server_Info *server, struct sockaddr *dstaddr);
+
+/* Reconnect SMBDirect session */
+int smbd_reconnect(struct TCP_Server_Info *server);
+
+/* Destroy SMBDirect session */
+void smbd_destroy(struct smbd_connection *info);
+
+/* Interface for carrying upper layer I/O through send/recv */
+int smbd_recv(
+	struct smbd_connection *rdma, char *buf, unsigned int to_read);
+int smbd_recv_page(
+	struct smbd_connection *rdma, struct page *page, unsigned int to_read);
+int smbd_send(struct smbd_connection *rdma, struct smb_rqst *rqst);
+
+enum mr_state {
+	MR_READY,
+	MR_REGISTERED,
+	MR_INVALIDATED,
+	MR_ERROR
+};
+
+struct smbd_mr {
+	struct smbd_connection	*conn;
+	struct list_head	list;
+	enum mr_state		state;
+	struct ib_mr		*mr;
+	struct scatterlist	*sgl;
+	int			sgl_count;
+	enum dma_data_direction	dir;
+	union {
+		struct ib_reg_wr	wr;
+		struct ib_send_wr	inv_wr;
+	};
+	struct ib_cqe		cqe;
+	bool			need_invalidate;
+	struct completion	invalidate_done;
+};
+
+/* Interfaces to register and deregister MR for RDMA read/write */
+struct smbd_mr *smbd_register_mr(
+	struct smbd_connection *rdma, struct page *pages[], int num_pages,
+	int tailsz, bool writing, bool need_invalidate);
+int smbd_deregister_mr(struct smbd_mr *mr);
 #endif
