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	Version: linux-6.0.1 spark-3.0.0 hadoop-3.2.0-src hadoop-3.3.0-src spark-2.4.7 linux-4.15.13 hadoop-2.7.4-src Revert   Change

 // SPDX-License-Identifier: GPL-2.0-or-later
 /*
  *   Copyright (C) 2017, Microsoft Corporation.
  *
  *   Author(s): Long Li <longli@microsoft.com>
  */
 #include <linux/module.h>
 #include <linux/highmem.h>
 #include "smbdirect.h"
 #include "cifs_debug.h"
 #include "cifsproto.h"
 #include "smb2proto.h"
 
 static struct smbd_response *get_empty_queue_buffer(
         struct smbd_connection *info);
 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 put_empty_packet(
         struct smbd_connection *info, struct smbd_response *response);
 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
 
 /* Port numbers for SMBD transport */
 #define SMB_PORT    445
 #define SMBD_PORT   5445
 
 /* Address lookup and resolve timeout in ms */
 #define RDMA_RESOLVE_TIMEOUT    5000
 
 /* SMBD negotiation timeout in seconds */
 #define SMBD_NEGOTIATE_TIMEOUT  120
 
 /* SMBD minimum receive size and fragmented sized defined in [MS-SMBD] */
 #define SMBD_MIN_RECEIVE_SIZE       128
 #define SMBD_MIN_FRAGMENTED_SIZE    131072
 
 /*
  * Default maximum number of RDMA read/write outstanding on this connection
  * This value is possibly decreased during QP creation on hardware limit
  */
 #define SMBD_CM_RESPONDER_RESOURCES 32
 
 /* Maximum number of retries on data transfer operations */
 #define SMBD_CM_RETRY           6
 /* No need to retry on Receiver Not Ready since SMBD manages credits */
 #define SMBD_CM_RNR_RETRY       0
 
 /*
  * User configurable initial values per SMBD transport connection
  * as defined in [MS-SMBD] 3.1.1.1
  * Those may change after a SMBD negotiation
  */
 /* The local peer's maximum number of credits to grant to the peer */
 int smbd_receive_credit_max = 255;
 
 /* The remote peer's credit request of local peer */
 int smbd_send_credit_target = 255;
 
 /* The maximum single message size can be sent to remote peer */
 int smbd_max_send_size = 1364;
 
 /*  The maximum fragmented upper-layer payload receive size supported */
 int smbd_max_fragmented_recv_size = 1024 * 1024;
 
 /*  The maximum single-message size which can be received */
 int smbd_max_receive_size = 8192;
 
 /* The timeout to initiate send of a keepalive message on idle */
 int smbd_keep_alive_interval = 120;
 
 /*
  * User configurable initial values for RDMA transport
  * The actual values used may be lower and are limited to hardware capabilities
  */
 /* Default maximum number of SGEs in a RDMA write/read */
 int smbd_max_frmr_depth = 2048;
 
 /* If payload is less than this byte, use RDMA send/recv not read/write */
 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=0xa0 will log all log_rdma_recv() and
  * log_rdma_event()
  */
 #define LOG_OUTGOING            0x1
 #define LOG_INCOMING            0x2
 #define LOG_READ            0x4
 #define LOG_WRITE           0x8
 #define LOG_RDMA_SEND           0x10
 #define LOG_RDMA_RECV           0x20
 #define LOG_KEEP_ALIVE          0x40
 #define LOG_RDMA_EVENT          0x80
 #define LOG_RDMA_MR         0x100
 static unsigned int smbd_logging_class;
 module_param(smbd_logging_class, uint, 0644);
 MODULE_PARM_DESC(smbd_logging_class,
     "Logging class for SMBD transport 0x0 to 0x100");
 
 #define ERR     0x0
 #define INFO        0x1
 static unsigned int smbd_logging_level = ERR;
 module_param(smbd_logging_level, uint, 0644);
 MODULE_PARM_DESC(smbd_logging_level,
     "Logging level for SMBD transport, 0 (default): error, 1: info");
 
 #define log_rdma(level, class, fmt, args...)                \
 do {                                    \
     if (level <= smbd_logging_level || class & smbd_logging_class)  \
         cifs_dbg(VFS, "%s:%d " fmt, __func__, __LINE__, ##args);\
 } while (0)
 
 #define log_outgoing(level, fmt, args...) \
         log_rdma(level, LOG_OUTGOING, fmt, ##args)
 #define log_incoming(level, fmt, args...) \
         log_rdma(level, LOG_INCOMING, fmt, ##args)
 #define log_read(level, fmt, args...)   log_rdma(level, LOG_READ, fmt, ##args)
 #define log_write(level, fmt, args...)  log_rdma(level, LOG_WRITE, fmt, ##args)
 #define log_rdma_send(level, fmt, args...) \
         log_rdma(level, LOG_RDMA_SEND, fmt, ##args)
 #define log_rdma_recv(level, fmt, args...) \
         log_rdma(level, LOG_RDMA_RECV, fmt, ##args)
 #define log_keep_alive(level, fmt, args...) \
         log_rdma(level, LOG_KEEP_ALIVE, fmt, ##args)
 #define log_rdma_event(level, fmt, args...) \
         log_rdma(level, LOG_RDMA_EVENT, fmt, ##args)
 #define log_rdma_mr(level, fmt, args...) \
         log_rdma(level, LOG_RDMA_MR, fmt, ##args)
 
 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)
 {
     queue_work(info->workqueue, &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(INFO, "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:
         log_rdma_event(INFO, "connected event=%d\n", event->event);
         info->transport_status = SMBD_CONNECTED;
         wake_up_interruptible(&info->conn_wait);
         break;
 
     case RDMA_CM_EVENT_CONNECT_ERROR:
     case RDMA_CM_EVENT_UNREACHABLE:
     case RDMA_CM_EVENT_REJECTED:
         log_rdma_event(INFO, "connecting failed event=%d\n", event->event);
         info->transport_status = SMBD_DISCONNECTED;
         wake_up_interruptible(&info->conn_wait);
         break;
 
     case RDMA_CM_EVENT_DEVICE_REMOVAL:
     case RDMA_CM_EVENT_DISCONNECTED:
         /* This happenes when we fail the negotiation */
         if (info->transport_status == SMBD_NEGOTIATE_FAILED) {
             info->transport_status = SMBD_DISCONNECTED;
             wake_up(&info->conn_wait);
             break;
         }
 
         info->transport_status = SMBD_DISCONNECTED;
         wake_up_interruptible(&info->disconn_wait);
         wake_up_interruptible(&info->wait_reassembly_queue);
         wake_up_interruptible_all(&info->wait_send_queue);
         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(ERR, "%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);
         break;
 
     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(INFO, "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(ERR, "wc->status=%d wc->opcode=%d\n",
             wc->status, wc->opcode);
         smbd_disconnect_rdma_connection(request->info);
     }
 
     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 (atomic_dec_and_test(&request->info->send_pending))
         wake_up(&request->info->wait_send_pending);
 
     wake_up(&request->info->wait_post_send);
 
     mempool_free(request, request->info->request_mempool);
 }
 
 static void dump_smbd_negotiate_resp(struct smbd_negotiate_resp *resp)
 {
     log_rdma_event(INFO, "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(ERR,
             "error: packet_length=%d\n", packet_length);
         return false;
     }
 
     if (le16_to_cpu(packet->negotiated_version) != SMBD_V1) {
         log_rdma_event(ERR, "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(ERR, "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(ERR, "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(ERR, "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(ERR, "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(ERR, "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;
 }
 
 static void smbd_post_send_credits(struct work_struct *work)
 {
     int ret = 0;
     int use_receive_queue = 1;
     int rc;
     struct smbd_response *response;
     struct smbd_connection *info =
         container_of(work, struct smbd_connection,
             post_send_credits_work);
 
     if (info->transport_status != SMBD_CONNECTED) {
         wake_up(&info->wait_receive_queues);
         return;
     }
 
     if (info->receive_credit_target >
         atomic_read(&info->receive_credits)) {
         while (true) {
             if (use_receive_queue)
                 response = get_receive_buffer(info);
             else
                 response = get_empty_queue_buffer(info);
             if (!response) {
                 /* now switch to emtpy packet queue */
                 if (use_receive_queue) {
                     use_receive_queue = 0;
                     continue;
                 } else
                     break;
             }
 
             response->type = SMBD_TRANSFER_DATA;
             response->first_segment = false;
             rc = smbd_post_recv(info, response);
             if (rc) {
                 log_rdma_recv(ERR,
                     "post_recv failed rc=%d\n", rc);
                 put_receive_buffer(info, response);
                 break;
             }
 
             ret++;
         }
     }
 
     spin_lock(&info->lock_new_credits_offered);
     info->new_credits_offered += ret;
     spin_unlock(&info->lock_new_credits_offered);
 
     /* Promptly send an immediate packet as defined in [MS-SMBD] 3.1.1.1 */
     info->send_immediate = true;
     if (atomic_read(&info->receive_credits) <
         info->receive_credit_target - 1) {
         if (info->keep_alive_requested == KEEP_ALIVE_PENDING ||
             info->send_immediate) {
             log_keep_alive(INFO, "send an empty message\n");
             smbd_post_send_empty(info);
         }
     }
 }
 
 /* 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;
     int data_length = 0;
 
     log_rdma_recv(INFO, "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(INFO, "wc->status=%d opcode=%d\n",
             wc->status, wc->opcode);
         smbd_disconnect_rdma_connection(info);
         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);
         data_length = le32_to_cpu(data_transfer->data_length);
 
         /*
          * If this is a packet with data playload place the data in
          * reassembly queue and wake up the reading thread
          */
         if (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,
                 data_length);
         } else
             put_empty_packet(info, response);
 
         if (data_length)
             wake_up_interruptible(&info->wait_reassembly_queue);
 
         atomic_dec(&info->receive_credits);
         info->receive_credit_target =
             le16_to_cpu(data_transfer->credits_requested);
         if (le16_to_cpu(data_transfer->credits_granted)) {
             atomic_add(le16_to_cpu(data_transfer->credits_granted),
                 &info->send_credits);
             /*
              * We have new send credits granted from remote peer
              * If any sender is waiting for credits, unblock it
              */
             wake_up_interruptible(&info->wait_send_queue);
         }
 
         log_incoming(INFO, "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));
 
         /* Send a KEEP_ALIVE response right away if requested */
         info->keep_alive_requested = KEEP_ALIVE_NONE;
         if (le16_to_cpu(data_transfer->flags) &
                 SMB_DIRECT_RESPONSE_REQUESTED) {
             info->keep_alive_requested = KEEP_ALIVE_PENDING;
         }
 
         return;
 
     default:
         log_rdma_recv(ERR,
             "unexpected response type=%d\n", response->type);
     }
 
 error:
     put_receive_buffer(info, response);
 }
 
 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(ERR, "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(ERR, "rdma_resolve_addr() failed %i\n", rc);
         goto out;
     }
     rc = wait_for_completion_interruptible_timeout(
         &info->ri_done, msecs_to_jiffies(RDMA_RESOLVE_TIMEOUT));
     /* e.g. if interrupted returns -ERESTARTSYS */
     if (rc < 0) {
         log_rdma_event(ERR, "rdma_resolve_addr timeout rc: %i\n", rc);
         goto out;
     }
     rc = info->ri_rc;
     if (rc) {
         log_rdma_event(ERR, "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(ERR, "rdma_resolve_route() failed %i\n", rc);
         goto out;
     }
     rc = wait_for_completion_interruptible_timeout(
         &info->ri_done, msecs_to_jiffies(RDMA_RESOLVE_TIMEOUT));
     /* e.g. if interrupted returns -ERESTARTSYS */
     if (rc < 0)  {
         log_rdma_event(ERR, "rdma_resolve_addr timeout rc: %i\n", rc);
         goto out;
     }
     rc = info->ri_rc;
     if (rc) {
         log_rdma_event(ERR, "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(ERR, "Fast Registration Work Requests (FRWR) is not supported\n");
         log_rdma_event(ERR, "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,
         smbd_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.kernel_cap_flags & IBK_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(ERR, "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;
     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(INFO, "sge addr=%llx length=%x lkey=%x\n",
         request->sge[0].addr,
         request->sge[0].length, request->sge[0].lkey);
 
     atomic_inc(&info->send_pending);
     rc = ib_post_send(info->id->qp, &send_wr, NULL);
     if (!rc)
         return 0;
 
     /* if we reach here, post send failed */
     log_rdma_send(ERR, "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);
 
     smbd_disconnect_rdma_connection(info);
 
 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 new_credits;
 
     spin_lock(&info->lock_new_credits_offered);
     new_credits = info->new_credits_offered;
     info->new_credits_offered = 0;
     spin_unlock(&info->lock_new_credits_offered);
 
     return new_credits;
 }
 
 /*
  * 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;
 }
 
 /* Post the send request */
 static int smbd_post_send(struct smbd_connection *info,
         struct smbd_request *request)
 {
     struct ib_send_wr send_wr;
     int rc, i;
 
     for (i = 0; i < request->num_sge; i++) {
         log_rdma_send(INFO,
             "rdma_request sge[%d] addr=%llu length=%u\n",
             i, request->sge[i].addr, request->sge[i].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;
 
     rc = ib_post_send(info->id->qp, &send_wr, NULL);
     if (rc) {
         log_rdma_send(ERR, "ib_post_send failed rc=%d\n", rc);
         smbd_disconnect_rdma_connection(info);
         rc = -EAGAIN;
     } 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;
 }
 
 static int smbd_post_send_sgl(struct smbd_connection *info,
     struct scatterlist *sgl, int data_length, int remaining_data_length)
 {
     int num_sgs;
     int i, rc;
     int header_length;
     struct smbd_request *request;
     struct smbd_data_transfer *packet;
     int new_credits;
     struct scatterlist *sg;
 
 wait_credit:
     /* Wait for send credits. A SMBD packet needs one credit */
     rc = wait_event_interruptible(info->wait_send_queue,
         atomic_read(&info->send_credits) > 0 ||
         info->transport_status != SMBD_CONNECTED);
     if (rc)
         goto err_wait_credit;
 
     if (info->transport_status != SMBD_CONNECTED) {
         log_outgoing(ERR, "disconnected not sending on wait_credit\n");
         rc = -EAGAIN;
         goto err_wait_credit;
     }
     if (unlikely(atomic_dec_return(&info->send_credits) < 0)) {
         atomic_inc(&info->send_credits);
         goto wait_credit;
     }
 
 wait_send_queue:
     wait_event(info->wait_post_send,
         atomic_read(&info->send_pending) < info->send_credit_target ||
         info->transport_status != SMBD_CONNECTED);
 
     if (info->transport_status != SMBD_CONNECTED) {
         log_outgoing(ERR, "disconnected not sending on wait_send_queue\n");
         rc = -EAGAIN;
         goto err_wait_send_queue;
     }
 
     if (unlikely(atomic_inc_return(&info->send_pending) >
                 info->send_credit_target)) {
         atomic_dec(&info->send_pending);
         goto wait_send_queue;
     }
 
     request = mempool_alloc(info->request_mempool, GFP_KERNEL);
     if (!request) {
         rc = -ENOMEM;
         goto err_alloc;
     }
 
     request->info = info;
 
     /* Fill in the packet header */
     packet = smbd_request_payload(request);
     packet->credits_requested = cpu_to_le16(info->send_credit_target);
 
     new_credits = manage_credits_prior_sending(info);
     atomic_add(new_credits, &info->receive_credits);
     packet->credits_granted = cpu_to_le16(new_credits);
 
     info->send_immediate = false;
 
     packet->flags = 0;
     if (manage_keep_alive_before_sending(info))
         packet->flags |= cpu_to_le16(SMB_DIRECT_RESPONSE_REQUESTED);
 
     packet->reserved = 0;
     if (!data_length)
         packet->data_offset = 0;
     else
         packet->data_offset = cpu_to_le32(24);
     packet->data_length = cpu_to_le32(data_length);
     packet->remaining_data_length = cpu_to_le32(remaining_data_length);
     packet->padding = 0;
 
     log_outgoing(INFO, "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 (!data_length)
         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_TO_DEVICE);
     if (ib_dma_mapping_error(info->id->device, request->sge[0].addr)) {
         rc = -EIO;
         request->sge[0].addr = 0;
         goto err_dma;
     }
 
     request->sge[0].length = header_length;
     request->sge[0].lkey = info->pd->local_dma_lkey;
 
     /* Fill in the packet data payload */
     num_sgs = sgl ? sg_nents(sgl) : 0;
     for_each_sg(sgl, sg, num_sgs, i) {
         request->sge[i+1].addr =
             ib_dma_map_page(info->id->device, sg_page(sg),
                    sg->offset, sg->length, DMA_TO_DEVICE);
         if (ib_dma_mapping_error(
                 info->id->device, request->sge[i+1].addr)) {
             rc = -EIO;
             request->sge[i+1].addr = 0;
             goto err_dma;
         }
         request->sge[i+1].length = sg->length;
         request->sge[i+1].lkey = info->pd->local_dma_lkey;
         request->num_sge++;
     }
 
     rc = smbd_post_send(info, request);
     if (!rc)
         return 0;
 
 err_dma:
     for (i = 0; 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);
     mempool_free(request, info->request_mempool);
 
     /* roll back receive credits and credits to be offered */
     spin_lock(&info->lock_new_credits_offered);
     info->new_credits_offered += new_credits;
     spin_unlock(&info->lock_new_credits_offered);
     atomic_sub(new_credits, &info->receive_credits);
 
 err_alloc:
     if (atomic_dec_and_test(&info->send_pending))
         wake_up(&info->wait_send_pending);
 
 err_wait_send_queue:
     /* roll back send credits and pending */
     atomic_inc(&info->send_credits);
 
 err_wait_credit:
     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 scatterlist sgl;
 
     sg_init_table(&sgl, 1);
     sg_set_page(&sgl, page, size, offset);
 
     return smbd_post_send_sgl(info, &sgl, size, remaining_data_length);
 }
 
 /*
  * 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)
 {
     info->count_send_empty++;
     return smbd_post_send_sgl(info, NULL, 0, 0);
 }
 
 /*
  * 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)
 {
     int i;
     u32 data_length = 0;
     struct scatterlist sgl[SMBDIRECT_MAX_SGE];
 
     if (n_vec > SMBDIRECT_MAX_SGE) {
         cifs_dbg(VFS, "Can't fit data to SGL, n_vec=%d\n", n_vec);
         return -EINVAL;
     }
 
     sg_init_table(sgl, n_vec);
     for (i = 0; i < n_vec; i++) {
         data_length += iov[i].iov_len;
         sg_set_buf(&sgl[i], iov[i].iov_base, iov[i].iov_len);
     }
 
     return smbd_post_send_sgl(info, sgl, data_length, remaining_data_length);
 }
 
 /*
  * 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;
     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;
 
     rc = ib_post_recv(info->id->qp, &recv_wr, NULL);
     if (rc) {
         ib_dma_unmap_single(info->id->device, response->sge.addr,
                     response->sge.length, DMA_FROM_DEVICE);
         smbd_disconnect_rdma_connection(info);
         log_rdma_recv(ERR, "ib_post_recv failed rc=%d\n", rc);
     }
 
     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(INFO, "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(INFO, "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;
 }
 
 static void put_empty_packet(
         struct smbd_connection *info, struct smbd_response *response)
 {
     spin_lock(&info->empty_packet_queue_lock);
     list_add_tail(&response->list, &info->empty_packet_queue);
     info->count_empty_packet_queue++;
     spin_unlock(&info->empty_packet_queue_lock);
 
     queue_work(info->workqueue, &info->post_send_credits_work);
 }
 
 /*
  * 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_queue_length++;
     /*
      * Make sure reassembly_data_length is updated after list and
      * reassembly_queue_length are updated. On the dequeue side
      * reassembly_data_length is checked without a lock to determine
      * if reassembly_queue_length and list is up to date
      */
     virt_wmb();
     info->reassembly_data_length += data_length;
     spin_unlock(&info->reassembly_queue_lock);
     info->count_reassembly_queue++;
     info->count_enqueue_reassembly_queue++;
 }
 
 /*
  * 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;
 }
 
 static struct smbd_response *get_empty_queue_buffer(
         struct smbd_connection *info)
 {
     struct smbd_response *ret = NULL;
     unsigned long flags;
 
     spin_lock_irqsave(&info->empty_packet_queue_lock, flags);
     if (!list_empty(&info->empty_packet_queue)) {
         ret = list_first_entry(
             &info->empty_packet_queue,
             struct smbd_response, list);
         list_del(&ret->list);
         info->count_empty_packet_queue--;
     }
     spin_unlock_irqrestore(&info->empty_packet_queue_lock, flags);
 
     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;
     unsigned long flags;
 
     spin_lock_irqsave(&info->receive_queue_lock, flags);
     if (!list_empty(&info->receive_queue)) {
         ret = list_first_entry(
             &info->receive_queue,
             struct smbd_response, list);
         list_del(&ret->list);
         info->count_receive_queue--;
         info->count_get_receive_buffer++;
     }
     spin_unlock_irqrestore(&info->receive_queue_lock, flags);
 
     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)
 {
     unsigned long flags;
 
     ib_dma_unmap_single(info->id->device, response->sge.addr,
         response->sge.length, DMA_FROM_DEVICE);
 
     spin_lock_irqsave(&info->receive_queue_lock, flags);
     list_add_tail(&response->list, &info->receive_queue);
     info->count_receive_queue++;
     info->count_put_receive_buffer++;
     spin_unlock_irqrestore(&info->receive_queue_lock, flags);
 
     queue_work(info->workqueue, &info->post_send_credits_work);
 }
 
 /* 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;
     info->reassembly_queue_length = 0;
 
     INIT_LIST_HEAD(&info->receive_queue);
     spin_lock_init(&info->receive_queue_lock);
     info->count_receive_queue = 0;
 
     INIT_LIST_HEAD(&info->empty_packet_queue);
     spin_lock_init(&info->empty_packet_queue_lock);
     info->count_empty_packet_queue = 0;
 
     init_waitqueue_head(&info->wait_receive_queues);
 
     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_queue++;
     }
 
     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_queue--;
 
         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);
 
     while ((response = get_empty_queue_buffer(info)))
         mempool_free(response, info->response_mempool);
 }
 
 /* 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(ERR,
             "error status info->keep_alive_requested=%d\n",
             info->keep_alive_requested);
         smbd_disconnect_rdma_connection(info);
         return;
     }
 
     log_keep_alive(INFO, "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 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
  */
 void smbd_destroy(struct TCP_Server_Info *server)
 {
     struct smbd_connection *info = server->smbd_conn;
     struct smbd_response *response;
     unsigned long flags;
 
     if (!info) {
         log_rdma_event(INFO, "rdma session already destroyed\n");
         return;
     }
 
     log_rdma_event(INFO, "destroying rdma session\n");
     if (info->transport_status != SMBD_DISCONNECTED) {
         rdma_disconnect(server->smbd_conn->id);
         log_rdma_event(INFO, "wait for transport being disconnected\n");
         wait_event_interruptible(
             info->disconn_wait,
             info->transport_status == SMBD_DISCONNECTED);
     }
 
     log_rdma_event(INFO, "destroying qp\n");
     ib_drain_qp(info->id->qp);
     rdma_destroy_qp(info->id);
 
     log_rdma_event(INFO, "cancelling idle timer\n");
     cancel_delayed_work_sync(&info->idle_timer_work);
 
     log_rdma_event(INFO, "wait for all send posted to IB to finish\n");
     wait_event(info->wait_send_pending,
         atomic_read(&info->send_pending) == 0);
 
     /* It's not possible for upper layer to get to reassembly */
     log_rdma_event(INFO, "drain the reassembly queue\n");
     do {
         spin_lock_irqsave(&info->reassembly_queue_lock, flags);
         response = _get_first_reassembly(info);
         if (response) {
             list_del(&response->list);
             spin_unlock_irqrestore(
                 &info->reassembly_queue_lock, flags);
             put_receive_buffer(info, response);
         } else
             spin_unlock_irqrestore(
                 &info->reassembly_queue_lock, flags);
     } while (response);
     info->reassembly_data_length = 0;
 
     log_rdma_event(INFO, "free receive buffers\n");
     wait_event(info->wait_receive_queues,
         info->count_receive_queue + info->count_empty_packet_queue
             == info->receive_credit_max);
     destroy_receive_buffers(info);
 
     /*
      * For performance reasons, memory registration and deregistration
      * are not locked by srv_mutex. It is possible some processes are
      * blocked on transport srv_mutex while holding memory registration.
      * Release the transport srv_mutex to allow them to hit the failure
      * path when sending data, and then release memory registartions.
      */
     log_rdma_event(INFO, "freeing mr list\n");
     wake_up_interruptible_all(&info->wait_mr);
     while (atomic_read(&info->mr_used_count)) {
         cifs_server_unlock(server);
         msleep(1000);
         cifs_server_lock(server);
     }
     destroy_mr_list(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;
 
     destroy_workqueue(info->workqueue);
     log_rdma_event(INFO,  "rdma session destroyed\n");
     kfree(info);
 }
 
 /*
  * 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(INFO, "reconnecting rdma session\n");
 
     if (!server->smbd_conn) {
         log_rdma_event(INFO, "rdma session already destroyed\n");
         goto create_conn;
     }
 
     /*
      * This is possible if transport is disconnected and we haven't received
      * notification from RDMA, but upper layer has detected timeout
      */
     if (server->smbd_conn->transport_status == SMBD_CONNECTED) {
         log_rdma_event(INFO, "disconnecting transport\n");
         smbd_destroy(server);
     }
 
 create_conn:
     log_rdma_event(INFO, "creating rdma session\n");
     server->smbd_conn = smbd_get_connection(
         server, (struct sockaddr *) &server->dstaddr);
 
     if (server->smbd_conn)
         cifs_dbg(VFS, "RDMA transport re-established\n");
 
     return server->smbd_conn ? 0 : -ENOENT;
 }
 
 static void destroy_caches_and_workqueue(struct smbd_connection *info)
 {
     destroy_receive_buffers(info);
     destroy_workqueue(info->workqueue);
     mempool_destroy(info->response_mempool);
     kmem_cache_destroy(info->response_cache);
     mempool_destroy(info->request_mempool);
     kmem_cache_destroy(info->request_cache);
 }
 
 #define MAX_NAME_LEN    80
 static int allocate_caches_and_workqueue(struct smbd_connection *info)
 {
     char name[MAX_NAME_LEN];
     int rc;
 
     scnprintf(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;
 
     scnprintf(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;
 
     scnprintf(name, MAX_NAME_LEN, "smbd_%p", info);
     info->workqueue = create_workqueue(name);
     if (!info->workqueue)
         goto out4;
 
     rc = allocate_receive_buffers(info, info->receive_credit_max);
     if (rc) {
         log_rdma_event(ERR, "failed to allocate receive buffers\n");
         goto out5;
     }
 
     return 0;
 
 out5:
     destroy_workqueue(info->workqueue);
 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 */
 static struct smbd_connection *_smbd_get_connection(
     struct TCP_Server_Info *server, struct sockaddr *dstaddr, int port)
 {
     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;
     struct ib_port_immutable port_immutable;
     u32 ird_ord_hdr[2];
 
     info = kzalloc(sizeof(struct smbd_connection), GFP_KERNEL);
     if (!info)
         return NULL;
 
     info->transport_status = SMBD_CONNECTING;
     rc = smbd_ia_open(info, dstaddr, port);
     if (rc) {
         log_rdma_event(INFO, "smbd_ia_open rc=%d\n", rc);
         goto create_id_failed;
     }
 
     if (smbd_send_credit_target > info->id->device->attrs.max_cqe ||
         smbd_send_credit_target > info->id->device->attrs.max_qp_wr) {
         log_rdma_event(ERR, "consider lowering send_credit_target = %d. Possible CQE overrun, device reporting max_cpe %d max_qp_wr %d\n",
                    smbd_send_credit_target,
                    info->id->device->attrs.max_cqe,
                    info->id->device->attrs.max_qp_wr);
         goto config_failed;
     }
 
     if (smbd_receive_credit_max > info->id->device->attrs.max_cqe ||
         smbd_receive_credit_max > info->id->device->attrs.max_qp_wr) {
         log_rdma_event(ERR, "consider lowering receive_credit_max = %d. Possible CQE overrun, device reporting max_cpe %d max_qp_wr %d\n",
                    smbd_receive_credit_max,
                    info->id->device->attrs.max_cqe,
                    info->id->device->attrs.max_qp_wr);
         goto config_failed;
     }
 
     info->receive_credit_max = smbd_receive_credit_max;
     info->send_credit_target = smbd_send_credit_target;
     info->max_send_size = smbd_max_send_size;
     info->max_fragmented_recv_size = smbd_max_fragmented_recv_size;
     info->max_receive_size = smbd_max_receive_size;
     info->keep_alive_interval = smbd_keep_alive_interval;
 
     if (info->id->device->attrs.max_send_sge < SMBDIRECT_MAX_SGE) {
         log_rdma_event(ERR,
             "warning: device max_send_sge = %d too small\n",
             info->id->device->attrs.max_send_sge);
         log_rdma_event(ERR, "Queue Pair creation may fail\n");
     }
     if (info->id->device->attrs.max_recv_sge < SMBDIRECT_MAX_SGE) {
         log_rdma_event(ERR,
             "warning: device max_recv_sge = %d too small\n",
             info->id->device->attrs.max_recv_sge);
         log_rdma_event(ERR, "Queue Pair creation may fail\n");
     }
 
     info->send_cq = NULL;
     info->recv_cq = NULL;
     info->send_cq =
         ib_alloc_cq_any(info->id->device, info,
                 info->send_credit_target, IB_POLL_SOFTIRQ);
     if (IS_ERR(info->send_cq)) {
         info->send_cq = NULL;
         goto alloc_cq_failed;
     }
 
     info->recv_cq =
         ib_alloc_cq_any(info->id->device, info,
                 info->receive_credit_max, IB_POLL_SOFTIRQ);
     if (IS_ERR(info->recv_cq)) {
         info->recv_cq = NULL;
         goto alloc_cq_failed;
     }
 
     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 = SMBDIRECT_MAX_SGE;
     qp_attr.cap.max_recv_sge = SMBDIRECT_MAX_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(ERR, "rdma_create_qp failed %i\n", rc);
         goto create_qp_failed;
     }
 
     memset(&conn_param, 0, sizeof(conn_param));
     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(INFO, "responder_resources=%d\n",
         info->responder_resources);
 
     /* Need to send IRD/ORD in private data for iWARP */
     info->id->device->ops.get_port_immutable(
         info->id->device, info->id->port_num, &port_immutable);
     if (port_immutable.core_cap_flags & RDMA_CORE_PORT_IWARP) {
         ird_ord_hdr[0] = info->responder_resources;
         ird_ord_hdr[1] = 1;
         conn_param.private_data = ird_ord_hdr;
         conn_param.private_data_len = sizeof(ird_ord_hdr);
     } else {
         conn_param.private_data = NULL;
         conn_param.private_data_len = 0;
     }
 
     conn_param.retry_count = SMBD_CM_RETRY;
     conn_param.rnr_retry_count = SMBD_CM_RNR_RETRY;
     conn_param.flow_control = 0;
 
     log_rdma_event(INFO, "connecting to IP %pI4 port %d\n",
         &addr_in->sin_addr, port);
 
     init_waitqueue_head(&info->conn_wait);
     init_waitqueue_head(&info->disconn_wait);
     init_waitqueue_head(&info->wait_reassembly_queue);
     rc = rdma_connect(info->id, &conn_param);
     if (rc) {
         log_rdma_event(ERR, "rdma_connect() failed with %i\n", rc);
         goto rdma_connect_failed;
     }
 
     wait_event_interruptible(
         info->conn_wait, info->transport_status != SMBD_CONNECTING);
 
     if (info->transport_status != SMBD_CONNECTED) {
         log_rdma_event(ERR, "rdma_connect failed port=%d\n", port);
         goto rdma_connect_failed;
     }
 
     log_rdma_event(INFO, "rdma_connect connected\n");
 
     rc = allocate_caches_and_workqueue(info);
     if (rc) {
         log_rdma_event(ERR, "cache allocation failed\n");
         goto allocate_cache_failed;
     }
 
     init_waitqueue_head(&info->wait_send_queue);
     INIT_DELAYED_WORK(&info->idle_timer_work, idle_connection_timer);
     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_post_send);
 
     INIT_WORK(&info->disconnect_work, smbd_disconnect_rdma_work);
     INIT_WORK(&info->post_send_credits_work, smbd_post_send_credits);
     info->new_credits_offered = 0;
     spin_lock_init(&info->lock_new_credits_offered);
 
     rc = smbd_negotiate(info);
     if (rc) {
         log_rdma_event(ERR, "smbd_negotiate rc=%d\n", rc);
         goto negotiation_failed;
     }
 
     rc = allocate_mr_list(info);
     if (rc) {
         log_rdma_mr(ERR, "memory registration allocation failed\n");
         goto allocate_mr_failed;
     }
 
     return info;
 
 allocate_mr_failed:
     /* At this point, need to a full transport shutdown */
     smbd_destroy(server);
     return NULL;
 
 negotiation_failed:
     cancel_delayed_work_sync(&info->idle_timer_work);
     destroy_caches_and_workqueue(info);
     info->transport_status = SMBD_NEGOTIATE_FAILED;
     init_waitqueue_head(&info->conn_wait);
     rdma_disconnect(info->id);
     wait_event(info->conn_wait,
         info->transport_status == SMBD_DISCONNECTED);
 
 allocate_cache_failed:
 rdma_connect_failed:
     rdma_destroy_qp(info->id);
 
 create_qp_failed:
 alloc_cq_failed:
     if (info->send_cq)
         ib_free_cq(info->send_cq);
     if (info->recv_cq)
         ib_free_cq(info->recv_cq);
 
 config_failed:
     ib_dealloc_pd(info->pd);
     rdma_destroy_id(info->id);
 
 create_id_failed:
     kfree(info);
     return NULL;
 }
 
 struct smbd_connection *smbd_get_connection(
     struct TCP_Server_Info *server, struct sockaddr *dstaddr)
 {
     struct smbd_connection *ret;
     int port = SMBD_PORT;
 
 try_again:
     ret = _smbd_get_connection(server, dstaddr, port);
 
     /* Try SMB_PORT if SMBD_PORT doesn't work */
     if (!ret && port == SMBD_PORT) {
         port = SMB_PORT;
         goto try_again;
     }
     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.
  */
 static int smbd_recv_buf(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:
     /*
      * 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 queue at the same time
      */
     log_read(INFO, "size=%d info->reassembly_data_length=%d\n", size,
         info->reassembly_data_length);
     if (info->reassembly_data_length >= size) {
         int queue_length;
         int queue_removed = 0;
 
         /*
          * Need to make sure reassembly_data_length is read before
          * reading reassembly_queue_length and calling
          * _get_first_reassembly. This call is lock free
          * as we never read at the end of the queue which are being
          * updated in SOFTIRQ as more data is received
          */
         virt_rmb();
         queue_length = info->reassembly_queue_length;
         data_read = 0;
         to_read = size;
         offset = info->first_entry_offset;
         while (data_read < size) {
             response = _get_first_reassembly(info);
             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(INFO, "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) {
                 queue_length--;
                 /*
                  * No need to lock if we are not at the
                  * end of the queue
                  */
                 if (queue_length)
                     list_del(&response->list);
                 else {
                     spin_lock_irq(
                         &info->reassembly_queue_lock);
                     list_del(&response->list);
                     spin_unlock_irq(
                         &info->reassembly_queue_lock);
                 }
                 queue_removed++;
                 info->count_reassembly_queue--;
                 info->count_dequeue_reassembly_queue++;
                 put_receive_buffer(info, response);
                 offset = 0;
                 log_read(INFO, "put_receive_buffer offset=0\n");
             } else
                 offset += to_copy;
 
             to_read -= to_copy;
             data_read += to_copy;
 
             log_read(INFO, "_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_irq(&info->reassembly_queue_lock);
         info->reassembly_data_length -= data_read;
         info->reassembly_queue_length -= queue_removed;
         spin_unlock_irq(&info->reassembly_queue_lock);
 
         info->first_entry_offset = offset;
         log_read(INFO, "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:
         return data_read;
     }
 
     log_read(INFO, "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 rc;
 
     if (info->transport_status != SMBD_CONNECTED) {
         log_read(ERR, "disconnected\n");
         return -ECONNABORTED;
     }
 
     goto again;
 }
 
 /*
  * 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
  */
 static int smbd_recv_page(struct smbd_connection *info,
         struct page *page, unsigned int page_offset,
         unsigned int to_read)
 {
     int ret;
     char *to_address;
     void *page_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 ret;
 
     /* now we can read from reassembly queue and not sleep */
     page_address = kmap_atomic(page);
     to_address = (char *) page_address + page_offset;
 
     log_read(INFO, "reading from page=%p address=%p to_read=%d\n",
         page, to_address, to_read);
 
     ret = smbd_recv_buf(info, to_address, to_read);
     kunmap_atomic(page_address);
 
     return ret;
 }
 
 /*
  * Receive data from transport
  * msg: a msghdr point to the buffer, can be ITER_KVEC or ITER_BVEC
  * return: total bytes read, or 0. SMB Direct will not do partial read.
  */
 int smbd_recv(struct smbd_connection *info, struct msghdr *msg)
 {
     char *buf;
     struct page *page;
     unsigned int to_read, page_offset;
     int rc;
 
     if (iov_iter_rw(&msg->msg_iter) == WRITE) {
         /* It's a bug in upper layer to get there */
         cifs_dbg(VFS, "Invalid msg iter dir %u\n",
              iov_iter_rw(&msg->msg_iter));
         rc = -EINVAL;
         goto out;
     }
 
     switch (iov_iter_type(&msg->msg_iter)) {
     case ITER_KVEC:
         buf = msg->msg_iter.kvec->iov_base;
         to_read = msg->msg_iter.kvec->iov_len;
         rc = smbd_recv_buf(info, buf, to_read);
         break;
 
     case ITER_BVEC:
         page = msg->msg_iter.bvec->bv_page;
         page_offset = msg->msg_iter.bvec->bv_offset;
         to_read = msg->msg_iter.bvec->bv_len;
         rc = smbd_recv_page(info, page, page_offset, to_read);
         break;
 
     default:
         /* It's a bug in upper layer to get there */
         cifs_dbg(VFS, "Invalid msg type %d\n",
              iov_iter_type(&msg->msg_iter));
         rc = -EINVAL;
     }
 
 out:
     /* SMBDirect will read it all or nothing */
     if (rc > 0)
         msg->msg_iter.count = 0;
     return rc;
 }
 
 /*
  * 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 TCP_Server_Info *server,
     int num_rqst, struct smb_rqst *rqst_array)
 {
     struct smbd_connection *info = server->smbd_conn;
     struct kvec vec;
     int nvecs;
     int size;
     unsigned int buflen, remaining_data_length;
     int start, i, j;
     int max_iov_size =
         info->max_send_size - sizeof(struct smbd_data_transfer);
     struct kvec *iov;
     int rc;
     struct smb_rqst *rqst;
     int rqst_idx;
 
     if (info->transport_status != SMBD_CONNECTED) {
         rc = -EAGAIN;
         goto done;
     }
 
     /*
      * Add in the page array if there is one. The caller needs to set
      * rq_tailsz to PAGE_SIZE when the buffer has multiple pages and
      * ends at page boundary
      */
     remaining_data_length = 0;
     for (i = 0; i < num_rqst; i++)
         remaining_data_length += smb_rqst_len(server, &rqst_array[i]);
 
     if (remaining_data_length > info->max_fragmented_send_size) {
         log_write(ERR, "payload size %d > max size %d\n",
             remaining_data_length, info->max_fragmented_send_size);
         rc = -EINVAL;
         goto done;
     }
 
     log_write(INFO, "num_rqst=%d total length=%u\n",
             num_rqst, remaining_data_length);
 
     rqst_idx = 0;
 next_rqst:
     rqst = &rqst_array[rqst_idx];
     iov = rqst->rq_iov;
 
     cifs_dbg(FYI, "Sending smb (RDMA): idx=%d smb_len=%lu\n",
         rqst_idx, smb_rqst_len(server, rqst));
     for (i = 0; i < rqst->rq_nvec; i++)
         dump_smb(iov[i].iov_base, iov[i].iov_len);
 
 
     log_write(INFO, "rqst_idx=%d nvec=%d rqst->rq_npages=%d rq_pagesz=%d rq_tailsz=%d buflen=%lu\n",
           rqst_idx, rqst->rq_nvec, rqst->rq_npages, rqst->rq_pagesz,
           rqst->rq_tailsz, smb_rqst_len(server, rqst));
 
     start = i = 0;
     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(INFO, "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(INFO, "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(INFO,
                         "sending vec j=%d iov_base=%p iov_len=%zu 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++;
                 if (i == rqst->rq_nvec)
                     break;
             }
             start = i;
             buflen = 0;
         } else {
             i++;
             if (i == rqst->rq_nvec) {
                 /* send out all remaining vecs */
                 remaining_data_length -= buflen;
                 log_write(INFO, "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(INFO, "looping i=%d buflen=%d\n", i, buflen);
     }
 
     /* now sending pages if there are any */
     for (i = 0; i < rqst->rq_npages; i++) {
         unsigned int offset;
 
         rqst_page_get_length(rqst, i, &buflen, &offset);
         nvecs = (buflen + max_iov_size - 1) / max_iov_size;
         log_write(INFO, "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(INFO, "sending pages i=%d offset=%d size=%d remaining_data_length=%d\n",
                   i, j * max_iov_size + offset, size,
                   remaining_data_length);
             rc = smbd_post_send_page(
                 info, rqst->rq_pages[i],
                 j*max_iov_size + offset,
                 size, remaining_data_length);
             if (rc)
                 goto done;
         }
     }
 
     rqst_idx++;
     if (rqst_idx < num_rqst)
         goto next_rqst;
 
 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_pending,
         atomic_read(&info->send_pending) == 0);
 
     return rc;
 }
 
 static void register_mr_done(struct ib_cq *cq, struct ib_wc *wc)
 {
     struct smbd_mr *mr;
     struct ib_cqe *cqe;
 
     if (wc->status) {
         log_rdma_mr(ERR, "status=%d\n", wc->status);
         cqe = wc->wr_cqe;
         mr = container_of(cqe, struct smbd_mr, cqe);
         smbd_disconnect_rdma_connection(mr->conn);
     }
 }
 
 /*
  * 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_ERROR) {
 
             /* recover this MR entry */
             rc = ib_dereg_mr(smbdirect_mr->mr);
             if (rc) {
                 log_rdma_mr(ERR,
                     "ib_dereg_mr failed rc=%x\n",
                     rc);
                 smbd_disconnect_rdma_connection(info);
                 continue;
             }
 
             smbdirect_mr->mr = ib_alloc_mr(
                 info->pd, info->mr_type,
                 info->max_frmr_depth);
             if (IS_ERR(smbdirect_mr->mr)) {
                 log_rdma_mr(ERR, "ib_alloc_mr failed mr_type=%x max_frmr_depth=%x\n",
                         info->mr_type,
                         info->max_frmr_depth);
                 smbd_disconnect_rdma_connection(info);
                 continue;
             }
         } else
             /* This MR is being used, don't recover it */
             continue;
 
         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);
     atomic_set(&info->mr_used_count, 0);
     init_waitqueue_head(&info->wait_for_mr_cleanup);
     /* Allocate more MRs (2x) than hardware responder_resources */
     for (i = 0; i < info->responder_resources * 2; 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(ERR, "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(ERR, "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(ERR, "wait_event_interruptible rc=%x\n", rc);
         return NULL;
     }
 
     if (info->transport_status != SMBD_CONNECTED) {
         log_rdma_mr(ERR, "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;
             spin_unlock(&info->mr_list_lock);
             atomic_dec(&info->mr_ready_count);
             atomic_inc(&info->mr_used_count);
             return ret;
         }
     }
 
     spin_unlock(&info->mr_list_lock);
     /*
      * It is possible that we could fail to get 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 offset, 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;
 
     if (num_pages > info->max_frmr_depth) {
         log_rdma_mr(ERR, "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(ERR, "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);
 
     log_rdma_mr(INFO, "num_pages=0x%x offset=0x%x tailsz=0x%x\n",
             num_pages, offset, tailsz);
 
     if (num_pages == 1) {
         sg_set_page(&smbdirect_mr->sgl[0], pages[0], tailsz, offset);
         goto skip_multiple_pages;
     }
 
     /* We have at least two pages to register */
     sg_set_page(
         &smbdirect_mr->sgl[0], pages[0], PAGE_SIZE - offset, offset);
     i = 1;
     while (i < num_pages - 1) {
         sg_set_page(&smbdirect_mr->sgl[i], pages[i], PAGE_SIZE, 0);
         i++;
     }
     sg_set_page(&smbdirect_mr->sgl[i], pages[i],
         tailsz ? tailsz : PAGE_SIZE, 0);
 
 skip_multiple_pages:
     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(ERR, "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(ERR,
             "ib_map_mr_sg failed rc = %d 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, NULL);
     if (!rc)
         return smbdirect_mr;
 
     log_rdma_mr(ERR, "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;
     if (atomic_dec_and_test(&info->mr_used_count))
         wake_up(&info->wait_for_mr_cleanup);
 
     smbd_disconnect_rdma_connection(info);
 
     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(ERR, "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;
     struct smbd_connection *info = smbdirect_mr->conn;
     int rc = 0;
 
     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, NULL);
         if (rc) {
             log_rdma_mr(ERR, "ib_post_send failed rc=%x\n", rc);
             smbd_disconnect_rdma_connection(info);
             goto done;
         }
         wait_for_completion(&smbdirect_mr->invalidate_done);
         smbdirect_mr->need_invalidate = false;
     } 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;
 
     if (smbdirect_mr->state == MR_INVALIDATED) {
         ib_dma_unmap_sg(
             info->id->device, smbdirect_mr->sgl,
             smbdirect_mr->sgl_count,
             smbdirect_mr->dir);
         smbdirect_mr->state = MR_READY;
         if (atomic_inc_return(&info->mr_ready_count) == 1)
             wake_up_interruptible(&info->wait_mr);
     } else
         /*
          * Schedule the work to do MR recovery for future I/Os MR
          * recovery is slow and don't want it to block current I/O
          */
         queue_work(info->workqueue, &info->mr_recovery_work);
 
 done:
     if (atomic_dec_and_test(&info->mr_used_count))
         wake_up(&info->wait_for_mr_cleanup);
 
     return rc;
 }

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