OSCL-LXR linux-6.0.1/​drivers/​infiniband/​core/​iwcm.c	Source navigation Diff markup Identifier search General search
	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

 /*
  * Copyright (c) 2004, 2005 Intel Corporation.  All rights reserved.
  * Copyright (c) 2004 Topspin Corporation.  All rights reserved.
  * Copyright (c) 2004, 2005 Voltaire Corporation.  All rights reserved.
  * Copyright (c) 2005 Sun Microsystems, Inc. All rights reserved.
  * Copyright (c) 2005 Open Grid Computing, Inc. All rights reserved.
  * Copyright (c) 2005 Network Appliance, Inc. All rights reserved.
  *
  * This software is available to you under a choice of one of two
  * licenses.  You may choose to be licensed under the terms of the GNU
  * General Public License (GPL) Version 2, available from the file
  * COPYING in the main directory of this source tree, or the
  * OpenIB.org BSD license below:
  *
  *     Redistribution and use in source and binary forms, with or
  *     without modification, are permitted provided that the following
  *     conditions are met:
  *
  *      - Redistributions of source code must retain the above
  *        copyright notice, this list of conditions and the following
  *        disclaimer.
  *
  *      - Redistributions in binary form must reproduce the above
  *        copyright notice, this list of conditions and the following
  *        disclaimer in the documentation and/or other materials
  *        provided with the distribution.
  *
  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  * SOFTWARE.
  *
  */
 #include <linux/dma-mapping.h>
 #include <linux/err.h>
 #include <linux/idr.h>
 #include <linux/interrupt.h>
 #include <linux/rbtree.h>
 #include <linux/sched.h>
 #include <linux/spinlock.h>
 #include <linux/workqueue.h>
 #include <linux/completion.h>
 #include <linux/slab.h>
 #include <linux/module.h>
 #include <linux/sysctl.h>
 
 #include <rdma/iw_cm.h>
 #include <rdma/ib_addr.h>
 #include <rdma/iw_portmap.h>
 #include <rdma/rdma_netlink.h>
 
 #include "iwcm.h"
 
 MODULE_AUTHOR("Tom Tucker");
 MODULE_DESCRIPTION("iWARP CM");
 MODULE_LICENSE("Dual BSD/GPL");
 
 static const char * const iwcm_rej_reason_strs[] = {
     [ECONNRESET]            = "reset by remote host",
     [ECONNREFUSED]          = "refused by remote application",
     [ETIMEDOUT]         = "setup timeout",
 };
 
 const char *__attribute_const__ iwcm_reject_msg(int reason)
 {
     size_t index;
 
     /* iWARP uses negative errnos */
     index = -reason;
 
     if (index < ARRAY_SIZE(iwcm_rej_reason_strs) &&
         iwcm_rej_reason_strs[index])
         return iwcm_rej_reason_strs[index];
     else
         return "unrecognized reason";
 }
 EXPORT_SYMBOL(iwcm_reject_msg);
 
 static struct rdma_nl_cbs iwcm_nl_cb_table[RDMA_NL_IWPM_NUM_OPS] = {
     [RDMA_NL_IWPM_REG_PID] = {.dump = iwpm_register_pid_cb},
     [RDMA_NL_IWPM_ADD_MAPPING] = {.dump = iwpm_add_mapping_cb},
     [RDMA_NL_IWPM_QUERY_MAPPING] = {.dump = iwpm_add_and_query_mapping_cb},
     [RDMA_NL_IWPM_REMOTE_INFO] = {.dump = iwpm_remote_info_cb},
     [RDMA_NL_IWPM_HANDLE_ERR] = {.dump = iwpm_mapping_error_cb},
     [RDMA_NL_IWPM_MAPINFO] = {.dump = iwpm_mapping_info_cb},
     [RDMA_NL_IWPM_MAPINFO_NUM] = {.dump = iwpm_ack_mapping_info_cb},
     [RDMA_NL_IWPM_HELLO] = {.dump = iwpm_hello_cb}
 };
 
 static struct workqueue_struct *iwcm_wq;
 struct iwcm_work {
     struct work_struct work;
     struct iwcm_id_private *cm_id;
     struct list_head list;
     struct iw_cm_event event;
     struct list_head free_list;
 };
 
 static unsigned int default_backlog = 256;
 
 static struct ctl_table_header *iwcm_ctl_table_hdr;
 static struct ctl_table iwcm_ctl_table[] = {
     {
         .procname   = "default_backlog",
         .data       = &default_backlog,
         .maxlen     = sizeof(default_backlog),
         .mode       = 0644,
         .proc_handler   = proc_dointvec,
     },
     { }
 };
 
 /*
  * The following services provide a mechanism for pre-allocating iwcm_work
  * elements.  The design pre-allocates them  based on the cm_id type:
  *  LISTENING IDS:  Get enough elements preallocated to handle the
  *          listen backlog.
  *  ACTIVE IDS: 4: CONNECT_REPLY, ESTABLISHED, DISCONNECT, CLOSE
  *  PASSIVE IDS:    3: ESTABLISHED, DISCONNECT, CLOSE
  *
  * Allocating them in connect and listen avoids having to deal
  * with allocation failures on the event upcall from the provider (which
  * is called in the interrupt context).
  *
  * One exception is when creating the cm_id for incoming connection requests.
  * There are two cases:
  * 1) in the event upcall, cm_event_handler(), for a listening cm_id.  If
  *    the backlog is exceeded, then no more connection request events will
  *    be processed.  cm_event_handler() returns -ENOMEM in this case.  Its up
  *    to the provider to reject the connection request.
  * 2) in the connection request workqueue handler, cm_conn_req_handler().
  *    If work elements cannot be allocated for the new connect request cm_id,
  *    then IWCM will call the provider reject method.  This is ok since
  *    cm_conn_req_handler() runs in the workqueue thread context.
  */
 
 static struct iwcm_work *get_work(struct iwcm_id_private *cm_id_priv)
 {
     struct iwcm_work *work;
 
     if (list_empty(&cm_id_priv->work_free_list))
         return NULL;
     work = list_entry(cm_id_priv->work_free_list.next, struct iwcm_work,
               free_list);
     list_del_init(&work->free_list);
     return work;
 }
 
 static void put_work(struct iwcm_work *work)
 {
     list_add(&work->free_list, &work->cm_id->work_free_list);
 }
 
 static void dealloc_work_entries(struct iwcm_id_private *cm_id_priv)
 {
     struct list_head *e, *tmp;
 
     list_for_each_safe(e, tmp, &cm_id_priv->work_free_list) {
         list_del(e);
         kfree(list_entry(e, struct iwcm_work, free_list));
     }
 }
 
 static int alloc_work_entries(struct iwcm_id_private *cm_id_priv, int count)
 {
     struct iwcm_work *work;
 
     BUG_ON(!list_empty(&cm_id_priv->work_free_list));
     while (count--) {
         work = kmalloc(sizeof(struct iwcm_work), GFP_KERNEL);
         if (!work) {
             dealloc_work_entries(cm_id_priv);
             return -ENOMEM;
         }
         work->cm_id = cm_id_priv;
         INIT_LIST_HEAD(&work->list);
         put_work(work);
     }
     return 0;
 }
 
 /*
  * Save private data from incoming connection requests to
  * iw_cm_event, so the low level driver doesn't have to. Adjust
  * the event ptr to point to the local copy.
  */
 static int copy_private_data(struct iw_cm_event *event)
 {
     void *p;
 
     p = kmemdup(event->private_data, event->private_data_len, GFP_ATOMIC);
     if (!p)
         return -ENOMEM;
     event->private_data = p;
     return 0;
 }
 
 static void free_cm_id(struct iwcm_id_private *cm_id_priv)
 {
     dealloc_work_entries(cm_id_priv);
     kfree(cm_id_priv);
 }
 
 /*
  * Release a reference on cm_id. If the last reference is being
  * released, free the cm_id and return 1.
  */
 static int iwcm_deref_id(struct iwcm_id_private *cm_id_priv)
 {
     if (refcount_dec_and_test(&cm_id_priv->refcount)) {
         BUG_ON(!list_empty(&cm_id_priv->work_list));
         free_cm_id(cm_id_priv);
         return 1;
     }
 
     return 0;
 }
 
 static void add_ref(struct iw_cm_id *cm_id)
 {
     struct iwcm_id_private *cm_id_priv;
     cm_id_priv = container_of(cm_id, struct iwcm_id_private, id);
     refcount_inc(&cm_id_priv->refcount);
 }
 
 static void rem_ref(struct iw_cm_id *cm_id)
 {
     struct iwcm_id_private *cm_id_priv;
 
     cm_id_priv = container_of(cm_id, struct iwcm_id_private, id);
 
     (void)iwcm_deref_id(cm_id_priv);
 }
 
 static int cm_event_handler(struct iw_cm_id *cm_id, struct iw_cm_event *event);
 
 struct iw_cm_id *iw_create_cm_id(struct ib_device *device,
                  iw_cm_handler cm_handler,
                  void *context)
 {
     struct iwcm_id_private *cm_id_priv;
 
     cm_id_priv = kzalloc(sizeof(*cm_id_priv), GFP_KERNEL);
     if (!cm_id_priv)
         return ERR_PTR(-ENOMEM);
 
     cm_id_priv->state = IW_CM_STATE_IDLE;
     cm_id_priv->id.device = device;
     cm_id_priv->id.cm_handler = cm_handler;
     cm_id_priv->id.context = context;
     cm_id_priv->id.event_handler = cm_event_handler;
     cm_id_priv->id.add_ref = add_ref;
     cm_id_priv->id.rem_ref = rem_ref;
     spin_lock_init(&cm_id_priv->lock);
     refcount_set(&cm_id_priv->refcount, 1);
     init_waitqueue_head(&cm_id_priv->connect_wait);
     init_completion(&cm_id_priv->destroy_comp);
     INIT_LIST_HEAD(&cm_id_priv->work_list);
     INIT_LIST_HEAD(&cm_id_priv->work_free_list);
 
     return &cm_id_priv->id;
 }
 EXPORT_SYMBOL(iw_create_cm_id);
 
 
 static int iwcm_modify_qp_err(struct ib_qp *qp)
 {
     struct ib_qp_attr qp_attr;
 
     if (!qp)
         return -EINVAL;
 
     qp_attr.qp_state = IB_QPS_ERR;
     return ib_modify_qp(qp, &qp_attr, IB_QP_STATE);
 }
 
 /*
  * This is really the RDMAC CLOSING state. It is most similar to the
  * IB SQD QP state.
  */
 static int iwcm_modify_qp_sqd(struct ib_qp *qp)
 {
     struct ib_qp_attr qp_attr;
 
     BUG_ON(qp == NULL);
     qp_attr.qp_state = IB_QPS_SQD;
     return ib_modify_qp(qp, &qp_attr, IB_QP_STATE);
 }
 
 /*
  * CM_ID <-- CLOSING
  *
  * Block if a passive or active connection is currently being processed. Then
  * process the event as follows:
  * - If we are ESTABLISHED, move to CLOSING and modify the QP state
  *   based on the abrupt flag
  * - If the connection is already in the CLOSING or IDLE state, the peer is
  *   disconnecting concurrently with us and we've already seen the
  *   DISCONNECT event -- ignore the request and return 0
  * - Disconnect on a listening endpoint returns -EINVAL
  */
 int iw_cm_disconnect(struct iw_cm_id *cm_id, int abrupt)
 {
     struct iwcm_id_private *cm_id_priv;
     unsigned long flags;
     int ret = 0;
     struct ib_qp *qp = NULL;
 
     cm_id_priv = container_of(cm_id, struct iwcm_id_private, id);
     /* Wait if we're currently in a connect or accept downcall */
     wait_event(cm_id_priv->connect_wait,
            !test_bit(IWCM_F_CONNECT_WAIT, &cm_id_priv->flags));
 
     spin_lock_irqsave(&cm_id_priv->lock, flags);
     switch (cm_id_priv->state) {
     case IW_CM_STATE_ESTABLISHED:
         cm_id_priv->state = IW_CM_STATE_CLOSING;
 
         /* QP could be <nul> for user-mode client */
         if (cm_id_priv->qp)
             qp = cm_id_priv->qp;
         else
             ret = -EINVAL;
         break;
     case IW_CM_STATE_LISTEN:
         ret = -EINVAL;
         break;
     case IW_CM_STATE_CLOSING:
         /* remote peer closed first */
     case IW_CM_STATE_IDLE:
         /* accept or connect returned !0 */
         break;
     case IW_CM_STATE_CONN_RECV:
         /*
          * App called disconnect before/without calling accept after
          * connect_request event delivered.
          */
         break;
     case IW_CM_STATE_CONN_SENT:
         /* Can only get here if wait above fails */
     default:
         BUG();
     }
     spin_unlock_irqrestore(&cm_id_priv->lock, flags);
 
     if (qp) {
         if (abrupt)
             ret = iwcm_modify_qp_err(qp);
         else
             ret = iwcm_modify_qp_sqd(qp);
 
         /*
          * If both sides are disconnecting the QP could
          * already be in ERR or SQD states
          */
         ret = 0;
     }
 
     return ret;
 }
 EXPORT_SYMBOL(iw_cm_disconnect);
 
 /*
  * CM_ID <-- DESTROYING
  *
  * Clean up all resources associated with the connection and release
  * the initial reference taken by iw_create_cm_id.
  */
 static void destroy_cm_id(struct iw_cm_id *cm_id)
 {
     struct iwcm_id_private *cm_id_priv;
     struct ib_qp *qp;
     unsigned long flags;
 
     cm_id_priv = container_of(cm_id, struct iwcm_id_private, id);
     /*
      * Wait if we're currently in a connect or accept downcall. A
      * listening endpoint should never block here.
      */
     wait_event(cm_id_priv->connect_wait,
            !test_bit(IWCM_F_CONNECT_WAIT, &cm_id_priv->flags));
 
     /*
      * Since we're deleting the cm_id, drop any events that
      * might arrive before the last dereference.
      */
     set_bit(IWCM_F_DROP_EVENTS, &cm_id_priv->flags);
 
     spin_lock_irqsave(&cm_id_priv->lock, flags);
     qp = cm_id_priv->qp;
     cm_id_priv->qp = NULL;
 
     switch (cm_id_priv->state) {
     case IW_CM_STATE_LISTEN:
         cm_id_priv->state = IW_CM_STATE_DESTROYING;
         spin_unlock_irqrestore(&cm_id_priv->lock, flags);
         /* destroy the listening endpoint */
         cm_id->device->ops.iw_destroy_listen(cm_id);
         spin_lock_irqsave(&cm_id_priv->lock, flags);
         break;
     case IW_CM_STATE_ESTABLISHED:
         cm_id_priv->state = IW_CM_STATE_DESTROYING;
         spin_unlock_irqrestore(&cm_id_priv->lock, flags);
         /* Abrupt close of the connection */
         (void)iwcm_modify_qp_err(qp);
         spin_lock_irqsave(&cm_id_priv->lock, flags);
         break;
     case IW_CM_STATE_IDLE:
     case IW_CM_STATE_CLOSING:
         cm_id_priv->state = IW_CM_STATE_DESTROYING;
         break;
     case IW_CM_STATE_CONN_RECV:
         /*
          * App called destroy before/without calling accept after
          * receiving connection request event notification or
          * returned non zero from the event callback function.
          * In either case, must tell the provider to reject.
          */
         cm_id_priv->state = IW_CM_STATE_DESTROYING;
         spin_unlock_irqrestore(&cm_id_priv->lock, flags);
         cm_id->device->ops.iw_reject(cm_id, NULL, 0);
         spin_lock_irqsave(&cm_id_priv->lock, flags);
         break;
     case IW_CM_STATE_CONN_SENT:
     case IW_CM_STATE_DESTROYING:
     default:
         BUG();
         break;
     }
     spin_unlock_irqrestore(&cm_id_priv->lock, flags);
     if (qp)
         cm_id_priv->id.device->ops.iw_rem_ref(qp);
 
     if (cm_id->mapped) {
         iwpm_remove_mapinfo(&cm_id->local_addr, &cm_id->m_local_addr);
         iwpm_remove_mapping(&cm_id->local_addr, RDMA_NL_IWCM);
     }
 
     (void)iwcm_deref_id(cm_id_priv);
 }
 
 /*
  * This function is only called by the application thread and cannot
  * be called by the event thread. The function will wait for all
  * references to be released on the cm_id and then kfree the cm_id
  * object.
  */
 void iw_destroy_cm_id(struct iw_cm_id *cm_id)
 {
     destroy_cm_id(cm_id);
 }
 EXPORT_SYMBOL(iw_destroy_cm_id);
 
 /**
  * iw_cm_check_wildcard - If IP address is 0 then use original
  * @pm_addr: sockaddr containing the ip to check for wildcard
  * @cm_addr: sockaddr containing the actual IP address
  * @cm_outaddr: sockaddr to set IP addr which leaving port
  *
  *  Checks the pm_addr for wildcard and then sets cm_outaddr's
  *  IP to the actual (cm_addr).
  */
 static void iw_cm_check_wildcard(struct sockaddr_storage *pm_addr,
                  struct sockaddr_storage *cm_addr,
                  struct sockaddr_storage *cm_outaddr)
 {
     if (pm_addr->ss_family == AF_INET) {
         struct sockaddr_in *pm4_addr = (struct sockaddr_in *)pm_addr;
 
         if (pm4_addr->sin_addr.s_addr == htonl(INADDR_ANY)) {
             struct sockaddr_in *cm4_addr =
                 (struct sockaddr_in *)cm_addr;
             struct sockaddr_in *cm4_outaddr =
                 (struct sockaddr_in *)cm_outaddr;
 
             cm4_outaddr->sin_addr = cm4_addr->sin_addr;
         }
     } else {
         struct sockaddr_in6 *pm6_addr = (struct sockaddr_in6 *)pm_addr;
 
         if (ipv6_addr_type(&pm6_addr->sin6_addr) == IPV6_ADDR_ANY) {
             struct sockaddr_in6 *cm6_addr =
                 (struct sockaddr_in6 *)cm_addr;
             struct sockaddr_in6 *cm6_outaddr =
                 (struct sockaddr_in6 *)cm_outaddr;
 
             cm6_outaddr->sin6_addr = cm6_addr->sin6_addr;
         }
     }
 }
 
 /**
  * iw_cm_map - Use portmapper to map the ports
  * @cm_id: connection manager pointer
  * @active: Indicates the active side when true
  * returns nonzero for error only if iwpm_create_mapinfo() fails
  *
  * Tries to add a mapping for a port using the Portmapper. If
  * successful in mapping the IP/Port it will check the remote
  * mapped IP address for a wildcard IP address and replace the
  * zero IP address with the remote_addr.
  */
 static int iw_cm_map(struct iw_cm_id *cm_id, bool active)
 {
     const char *devname = dev_name(&cm_id->device->dev);
     const char *ifname = cm_id->device->iw_ifname;
     struct iwpm_dev_data pm_reg_msg = {};
     struct iwpm_sa_data pm_msg;
     int status;
 
     if (strlen(devname) >= sizeof(pm_reg_msg.dev_name) ||
         strlen(ifname) >= sizeof(pm_reg_msg.if_name))
         return -EINVAL;
 
     cm_id->m_local_addr = cm_id->local_addr;
     cm_id->m_remote_addr = cm_id->remote_addr;
 
     strcpy(pm_reg_msg.dev_name, devname);
     strcpy(pm_reg_msg.if_name, ifname);
 
     if (iwpm_register_pid(&pm_reg_msg, RDMA_NL_IWCM) ||
         !iwpm_valid_pid())
         return 0;
 
     cm_id->mapped = true;
     pm_msg.loc_addr = cm_id->local_addr;
     pm_msg.rem_addr = cm_id->remote_addr;
     pm_msg.flags = (cm_id->device->iw_driver_flags & IW_F_NO_PORT_MAP) ?
                IWPM_FLAGS_NO_PORT_MAP : 0;
     if (active)
         status = iwpm_add_and_query_mapping(&pm_msg,
                             RDMA_NL_IWCM);
     else
         status = iwpm_add_mapping(&pm_msg, RDMA_NL_IWCM);
 
     if (!status) {
         cm_id->m_local_addr = pm_msg.mapped_loc_addr;
         if (active) {
             cm_id->m_remote_addr = pm_msg.mapped_rem_addr;
             iw_cm_check_wildcard(&pm_msg.mapped_rem_addr,
                          &cm_id->remote_addr,
                          &cm_id->m_remote_addr);
         }
     }
 
     return iwpm_create_mapinfo(&cm_id->local_addr,
                    &cm_id->m_local_addr,
                    RDMA_NL_IWCM, pm_msg.flags);
 }
 
 /*
  * CM_ID <-- LISTEN
  *
  * Start listening for connect requests. Generates one CONNECT_REQUEST
  * event for each inbound connect request.
  */
 int iw_cm_listen(struct iw_cm_id *cm_id, int backlog)
 {
     struct iwcm_id_private *cm_id_priv;
     unsigned long flags;
     int ret;
 
     cm_id_priv = container_of(cm_id, struct iwcm_id_private, id);
 
     if (!backlog)
         backlog = default_backlog;
 
     ret = alloc_work_entries(cm_id_priv, backlog);
     if (ret)
         return ret;
 
     spin_lock_irqsave(&cm_id_priv->lock, flags);
     switch (cm_id_priv->state) {
     case IW_CM_STATE_IDLE:
         cm_id_priv->state = IW_CM_STATE_LISTEN;
         spin_unlock_irqrestore(&cm_id_priv->lock, flags);
         ret = iw_cm_map(cm_id, false);
         if (!ret)
             ret = cm_id->device->ops.iw_create_listen(cm_id,
                                   backlog);
         if (ret)
             cm_id_priv->state = IW_CM_STATE_IDLE;
         spin_lock_irqsave(&cm_id_priv->lock, flags);
         break;
     default:
         ret = -EINVAL;
     }
     spin_unlock_irqrestore(&cm_id_priv->lock, flags);
 
     return ret;
 }
 EXPORT_SYMBOL(iw_cm_listen);
 
 /*
  * CM_ID <-- IDLE
  *
  * Rejects an inbound connection request. No events are generated.
  */
 int iw_cm_reject(struct iw_cm_id *cm_id,
          const void *private_data,
          u8 private_data_len)
 {
     struct iwcm_id_private *cm_id_priv;
     unsigned long flags;
     int ret;
 
     cm_id_priv = container_of(cm_id, struct iwcm_id_private, id);
     set_bit(IWCM_F_CONNECT_WAIT, &cm_id_priv->flags);
 
     spin_lock_irqsave(&cm_id_priv->lock, flags);
     if (cm_id_priv->state != IW_CM_STATE_CONN_RECV) {
         spin_unlock_irqrestore(&cm_id_priv->lock, flags);
         clear_bit(IWCM_F_CONNECT_WAIT, &cm_id_priv->flags);
         wake_up_all(&cm_id_priv->connect_wait);
         return -EINVAL;
     }
     cm_id_priv->state = IW_CM_STATE_IDLE;
     spin_unlock_irqrestore(&cm_id_priv->lock, flags);
 
     ret = cm_id->device->ops.iw_reject(cm_id, private_data,
                       private_data_len);
 
     clear_bit(IWCM_F_CONNECT_WAIT, &cm_id_priv->flags);
     wake_up_all(&cm_id_priv->connect_wait);
 
     return ret;
 }
 EXPORT_SYMBOL(iw_cm_reject);
 
 /*
  * CM_ID <-- ESTABLISHED
  *
  * Accepts an inbound connection request and generates an ESTABLISHED
  * event. Callers of iw_cm_disconnect and iw_destroy_cm_id will block
  * until the ESTABLISHED event is received from the provider.
  */
 int iw_cm_accept(struct iw_cm_id *cm_id,
          struct iw_cm_conn_param *iw_param)
 {
     struct iwcm_id_private *cm_id_priv;
     struct ib_qp *qp;
     unsigned long flags;
     int ret;
 
     cm_id_priv = container_of(cm_id, struct iwcm_id_private, id);
     set_bit(IWCM_F_CONNECT_WAIT, &cm_id_priv->flags);
 
     spin_lock_irqsave(&cm_id_priv->lock, flags);
     if (cm_id_priv->state != IW_CM_STATE_CONN_RECV) {
         spin_unlock_irqrestore(&cm_id_priv->lock, flags);
         clear_bit(IWCM_F_CONNECT_WAIT, &cm_id_priv->flags);
         wake_up_all(&cm_id_priv->connect_wait);
         return -EINVAL;
     }
     /* Get the ib_qp given the QPN */
     qp = cm_id->device->ops.iw_get_qp(cm_id->device, iw_param->qpn);
     if (!qp) {
         spin_unlock_irqrestore(&cm_id_priv->lock, flags);
         clear_bit(IWCM_F_CONNECT_WAIT, &cm_id_priv->flags);
         wake_up_all(&cm_id_priv->connect_wait);
         return -EINVAL;
     }
     cm_id->device->ops.iw_add_ref(qp);
     cm_id_priv->qp = qp;
     spin_unlock_irqrestore(&cm_id_priv->lock, flags);
 
     ret = cm_id->device->ops.iw_accept(cm_id, iw_param);
     if (ret) {
         /* An error on accept precludes provider events */
         BUG_ON(cm_id_priv->state != IW_CM_STATE_CONN_RECV);
         cm_id_priv->state = IW_CM_STATE_IDLE;
         spin_lock_irqsave(&cm_id_priv->lock, flags);
         qp = cm_id_priv->qp;
         cm_id_priv->qp = NULL;
         spin_unlock_irqrestore(&cm_id_priv->lock, flags);
         if (qp)
             cm_id->device->ops.iw_rem_ref(qp);
         clear_bit(IWCM_F_CONNECT_WAIT, &cm_id_priv->flags);
         wake_up_all(&cm_id_priv->connect_wait);
     }
 
     return ret;
 }
 EXPORT_SYMBOL(iw_cm_accept);
 
 /*
  * Active Side: CM_ID <-- CONN_SENT
  *
  * If successful, results in the generation of a CONNECT_REPLY
  * event. iw_cm_disconnect and iw_cm_destroy will block until the
  * CONNECT_REPLY event is received from the provider.
  */
 int iw_cm_connect(struct iw_cm_id *cm_id, struct iw_cm_conn_param *iw_param)
 {
     struct iwcm_id_private *cm_id_priv;
     int ret;
     unsigned long flags;
     struct ib_qp *qp = NULL;
 
     cm_id_priv = container_of(cm_id, struct iwcm_id_private, id);
 
     ret = alloc_work_entries(cm_id_priv, 4);
     if (ret)
         return ret;
 
     set_bit(IWCM_F_CONNECT_WAIT, &cm_id_priv->flags);
     spin_lock_irqsave(&cm_id_priv->lock, flags);
 
     if (cm_id_priv->state != IW_CM_STATE_IDLE) {
         ret = -EINVAL;
         goto err;
     }
 
     /* Get the ib_qp given the QPN */
     qp = cm_id->device->ops.iw_get_qp(cm_id->device, iw_param->qpn);
     if (!qp) {
         ret = -EINVAL;
         goto err;
     }
     cm_id->device->ops.iw_add_ref(qp);
     cm_id_priv->qp = qp;
     cm_id_priv->state = IW_CM_STATE_CONN_SENT;
     spin_unlock_irqrestore(&cm_id_priv->lock, flags);
 
     ret = iw_cm_map(cm_id, true);
     if (!ret)
         ret = cm_id->device->ops.iw_connect(cm_id, iw_param);
     if (!ret)
         return 0;   /* success */
 
     spin_lock_irqsave(&cm_id_priv->lock, flags);
     qp = cm_id_priv->qp;
     cm_id_priv->qp = NULL;
     cm_id_priv->state = IW_CM_STATE_IDLE;
 err:
     spin_unlock_irqrestore(&cm_id_priv->lock, flags);
     if (qp)
         cm_id->device->ops.iw_rem_ref(qp);
     clear_bit(IWCM_F_CONNECT_WAIT, &cm_id_priv->flags);
     wake_up_all(&cm_id_priv->connect_wait);
     return ret;
 }
 EXPORT_SYMBOL(iw_cm_connect);
 
 /*
  * Passive Side: new CM_ID <-- CONN_RECV
  *
  * Handles an inbound connect request. The function creates a new
  * iw_cm_id to represent the new connection and inherits the client
  * callback function and other attributes from the listening parent.
  *
  * The work item contains a pointer to the listen_cm_id and the event. The
  * listen_cm_id contains the client cm_handler, context and
  * device. These are copied when the device is cloned. The event
  * contains the new four tuple.
  *
  * An error on the child should not affect the parent, so this
  * function does not return a value.
  */
 static void cm_conn_req_handler(struct iwcm_id_private *listen_id_priv,
                 struct iw_cm_event *iw_event)
 {
     unsigned long flags;
     struct iw_cm_id *cm_id;
     struct iwcm_id_private *cm_id_priv;
     int ret;
 
     /*
      * The provider should never generate a connection request
      * event with a bad status.
      */
     BUG_ON(iw_event->status);
 
     cm_id = iw_create_cm_id(listen_id_priv->id.device,
                 listen_id_priv->id.cm_handler,
                 listen_id_priv->id.context);
     /* If the cm_id could not be created, ignore the request */
     if (IS_ERR(cm_id))
         goto out;
 
     cm_id->provider_data = iw_event->provider_data;
     cm_id->m_local_addr = iw_event->local_addr;
     cm_id->m_remote_addr = iw_event->remote_addr;
     cm_id->local_addr = listen_id_priv->id.local_addr;
 
     ret = iwpm_get_remote_info(&listen_id_priv->id.m_local_addr,
                    &iw_event->remote_addr,
                    &cm_id->remote_addr,
                    RDMA_NL_IWCM);
     if (ret) {
         cm_id->remote_addr = iw_event->remote_addr;
     } else {
         iw_cm_check_wildcard(&listen_id_priv->id.m_local_addr,
                      &iw_event->local_addr,
                      &cm_id->local_addr);
         iw_event->local_addr = cm_id->local_addr;
         iw_event->remote_addr = cm_id->remote_addr;
     }
 
     cm_id_priv = container_of(cm_id, struct iwcm_id_private, id);
     cm_id_priv->state = IW_CM_STATE_CONN_RECV;
 
     /*
      * We could be destroying the listening id. If so, ignore this
      * upcall.
      */
     spin_lock_irqsave(&listen_id_priv->lock, flags);
     if (listen_id_priv->state != IW_CM_STATE_LISTEN) {
         spin_unlock_irqrestore(&listen_id_priv->lock, flags);
         iw_cm_reject(cm_id, NULL, 0);
         iw_destroy_cm_id(cm_id);
         goto out;
     }
     spin_unlock_irqrestore(&listen_id_priv->lock, flags);
 
     ret = alloc_work_entries(cm_id_priv, 3);
     if (ret) {
         iw_cm_reject(cm_id, NULL, 0);
         iw_destroy_cm_id(cm_id);
         goto out;
     }
 
     /* Call the client CM handler */
     ret = cm_id->cm_handler(cm_id, iw_event);
     if (ret) {
         iw_cm_reject(cm_id, NULL, 0);
         iw_destroy_cm_id(cm_id);
     }
 
 out:
     if (iw_event->private_data_len)
         kfree(iw_event->private_data);
 }
 
 /*
  * Passive Side: CM_ID <-- ESTABLISHED
  *
  * The provider generated an ESTABLISHED event which means that
  * the MPA negotion has completed successfully and we are now in MPA
  * FPDU mode.
  *
  * This event can only be received in the CONN_RECV state. If the
  * remote peer closed, the ESTABLISHED event would be received followed
  * by the CLOSE event. If the app closes, it will block until we wake
  * it up after processing this event.
  */
 static int cm_conn_est_handler(struct iwcm_id_private *cm_id_priv,
                    struct iw_cm_event *iw_event)
 {
     unsigned long flags;
     int ret;
 
     spin_lock_irqsave(&cm_id_priv->lock, flags);
 
     /*
      * We clear the CONNECT_WAIT bit here to allow the callback
      * function to call iw_cm_disconnect. Calling iw_destroy_cm_id
      * from a callback handler is not allowed.
      */
     clear_bit(IWCM_F_CONNECT_WAIT, &cm_id_priv->flags);
     BUG_ON(cm_id_priv->state != IW_CM_STATE_CONN_RECV);
     cm_id_priv->state = IW_CM_STATE_ESTABLISHED;
     spin_unlock_irqrestore(&cm_id_priv->lock, flags);
     ret = cm_id_priv->id.cm_handler(&cm_id_priv->id, iw_event);
     wake_up_all(&cm_id_priv->connect_wait);
 
     return ret;
 }
 
 /*
  * Active Side: CM_ID <-- ESTABLISHED
  *
  * The app has called connect and is waiting for the established event to
  * post it's requests to the server. This event will wake up anyone
  * blocked in iw_cm_disconnect or iw_destroy_id.
  */
 static int cm_conn_rep_handler(struct iwcm_id_private *cm_id_priv,
                    struct iw_cm_event *iw_event)
 {
     struct ib_qp *qp = NULL;
     unsigned long flags;
     int ret;
 
     spin_lock_irqsave(&cm_id_priv->lock, flags);
     /*
      * Clear the connect wait bit so a callback function calling
      * iw_cm_disconnect will not wait and deadlock this thread
      */
     clear_bit(IWCM_F_CONNECT_WAIT, &cm_id_priv->flags);
     BUG_ON(cm_id_priv->state != IW_CM_STATE_CONN_SENT);
     if (iw_event->status == 0) {
         cm_id_priv->id.m_local_addr = iw_event->local_addr;
         cm_id_priv->id.m_remote_addr = iw_event->remote_addr;
         iw_event->local_addr = cm_id_priv->id.local_addr;
         iw_event->remote_addr = cm_id_priv->id.remote_addr;
         cm_id_priv->state = IW_CM_STATE_ESTABLISHED;
     } else {
         /* REJECTED or RESET */
         qp = cm_id_priv->qp;
         cm_id_priv->qp = NULL;
         cm_id_priv->state = IW_CM_STATE_IDLE;
     }
     spin_unlock_irqrestore(&cm_id_priv->lock, flags);
     if (qp)
         cm_id_priv->id.device->ops.iw_rem_ref(qp);
     ret = cm_id_priv->id.cm_handler(&cm_id_priv->id, iw_event);
 
     if (iw_event->private_data_len)
         kfree(iw_event->private_data);
 
     /* Wake up waiters on connect complete */
     wake_up_all(&cm_id_priv->connect_wait);
 
     return ret;
 }
 
 /*
  * CM_ID <-- CLOSING
  *
  * If in the ESTABLISHED state, move to CLOSING.
  */
 static void cm_disconnect_handler(struct iwcm_id_private *cm_id_priv,
                   struct iw_cm_event *iw_event)
 {
     unsigned long flags;
 
     spin_lock_irqsave(&cm_id_priv->lock, flags);
     if (cm_id_priv->state == IW_CM_STATE_ESTABLISHED)
         cm_id_priv->state = IW_CM_STATE_CLOSING;
     spin_unlock_irqrestore(&cm_id_priv->lock, flags);
 }
 
 /*
  * CM_ID <-- IDLE
  *
  * If in the ESTBLISHED or CLOSING states, the QP will have have been
  * moved by the provider to the ERR state. Disassociate the CM_ID from
  * the QP,  move to IDLE, and remove the 'connected' reference.
  *
  * If in some other state, the cm_id was destroyed asynchronously.
  * This is the last reference that will result in waking up
  * the app thread blocked in iw_destroy_cm_id.
  */
 static int cm_close_handler(struct iwcm_id_private *cm_id_priv,
                   struct iw_cm_event *iw_event)
 {
     struct ib_qp *qp;
     unsigned long flags;
     int ret = 0, notify_event = 0;
     spin_lock_irqsave(&cm_id_priv->lock, flags);
     qp = cm_id_priv->qp;
     cm_id_priv->qp = NULL;
 
     switch (cm_id_priv->state) {
     case IW_CM_STATE_ESTABLISHED:
     case IW_CM_STATE_CLOSING:
         cm_id_priv->state = IW_CM_STATE_IDLE;
         notify_event = 1;
         break;
     case IW_CM_STATE_DESTROYING:
         break;
     default:
         BUG();
     }
     spin_unlock_irqrestore(&cm_id_priv->lock, flags);
 
     if (qp)
         cm_id_priv->id.device->ops.iw_rem_ref(qp);
     if (notify_event)
         ret = cm_id_priv->id.cm_handler(&cm_id_priv->id, iw_event);
     return ret;
 }
 
 static int process_event(struct iwcm_id_private *cm_id_priv,
              struct iw_cm_event *iw_event)
 {
     int ret = 0;
 
     switch (iw_event->event) {
     case IW_CM_EVENT_CONNECT_REQUEST:
         cm_conn_req_handler(cm_id_priv, iw_event);
         break;
     case IW_CM_EVENT_CONNECT_REPLY:
         ret = cm_conn_rep_handler(cm_id_priv, iw_event);
         break;
     case IW_CM_EVENT_ESTABLISHED:
         ret = cm_conn_est_handler(cm_id_priv, iw_event);
         break;
     case IW_CM_EVENT_DISCONNECT:
         cm_disconnect_handler(cm_id_priv, iw_event);
         break;
     case IW_CM_EVENT_CLOSE:
         ret = cm_close_handler(cm_id_priv, iw_event);
         break;
     default:
         BUG();
     }
 
     return ret;
 }
 
 /*
  * Process events on the work_list for the cm_id. If the callback
  * function requests that the cm_id be deleted, a flag is set in the
  * cm_id flags to indicate that when the last reference is
  * removed, the cm_id is to be destroyed. This is necessary to
  * distinguish between an object that will be destroyed by the app
  * thread asleep on the destroy_comp list vs. an object destroyed
  * here synchronously when the last reference is removed.
  */
 static void cm_work_handler(struct work_struct *_work)
 {
     struct iwcm_work *work = container_of(_work, struct iwcm_work, work);
     struct iw_cm_event levent;
     struct iwcm_id_private *cm_id_priv = work->cm_id;
     unsigned long flags;
     int empty;
     int ret = 0;
 
     spin_lock_irqsave(&cm_id_priv->lock, flags);
     empty = list_empty(&cm_id_priv->work_list);
     while (!empty) {
         work = list_entry(cm_id_priv->work_list.next,
                   struct iwcm_work, list);
         list_del_init(&work->list);
         empty = list_empty(&cm_id_priv->work_list);
         levent = work->event;
         put_work(work);
         spin_unlock_irqrestore(&cm_id_priv->lock, flags);
 
         if (!test_bit(IWCM_F_DROP_EVENTS, &cm_id_priv->flags)) {
             ret = process_event(cm_id_priv, &levent);
             if (ret)
                 destroy_cm_id(&cm_id_priv->id);
         } else
             pr_debug("dropping event %d\n", levent.event);
         if (iwcm_deref_id(cm_id_priv))
             return;
         if (empty)
             return;
         spin_lock_irqsave(&cm_id_priv->lock, flags);
     }
     spin_unlock_irqrestore(&cm_id_priv->lock, flags);
 }
 
 /*
  * This function is called on interrupt context. Schedule events on
  * the iwcm_wq thread to allow callback functions to downcall into
  * the CM and/or block.  Events are queued to a per-CM_ID
  * work_list. If this is the first event on the work_list, the work
  * element is also queued on the iwcm_wq thread.
  *
  * Each event holds a reference on the cm_id. Until the last posted
  * event has been delivered and processed, the cm_id cannot be
  * deleted.
  *
  * Returns:
  *        0 - the event was handled.
  *  -ENOMEM - the event was not handled due to lack of resources.
  */
 static int cm_event_handler(struct iw_cm_id *cm_id,
                  struct iw_cm_event *iw_event)
 {
     struct iwcm_work *work;
     struct iwcm_id_private *cm_id_priv;
     unsigned long flags;
     int ret = 0;
 
     cm_id_priv = container_of(cm_id, struct iwcm_id_private, id);
 
     spin_lock_irqsave(&cm_id_priv->lock, flags);
     work = get_work(cm_id_priv);
     if (!work) {
         ret = -ENOMEM;
         goto out;
     }
 
     INIT_WORK(&work->work, cm_work_handler);
     work->cm_id = cm_id_priv;
     work->event = *iw_event;
 
     if ((work->event.event == IW_CM_EVENT_CONNECT_REQUEST ||
          work->event.event == IW_CM_EVENT_CONNECT_REPLY) &&
         work->event.private_data_len) {
         ret = copy_private_data(&work->event);
         if (ret) {
             put_work(work);
             goto out;
         }
     }
 
     refcount_inc(&cm_id_priv->refcount);
     if (list_empty(&cm_id_priv->work_list)) {
         list_add_tail(&work->list, &cm_id_priv->work_list);
         queue_work(iwcm_wq, &work->work);
     } else
         list_add_tail(&work->list, &cm_id_priv->work_list);
 out:
     spin_unlock_irqrestore(&cm_id_priv->lock, flags);
     return ret;
 }
 
 static int iwcm_init_qp_init_attr(struct iwcm_id_private *cm_id_priv,
                   struct ib_qp_attr *qp_attr,
                   int *qp_attr_mask)
 {
     unsigned long flags;
     int ret;
 
     spin_lock_irqsave(&cm_id_priv->lock, flags);
     switch (cm_id_priv->state) {
     case IW_CM_STATE_IDLE:
     case IW_CM_STATE_CONN_SENT:
     case IW_CM_STATE_CONN_RECV:
     case IW_CM_STATE_ESTABLISHED:
         *qp_attr_mask = IB_QP_STATE | IB_QP_ACCESS_FLAGS;
         qp_attr->qp_access_flags = IB_ACCESS_REMOTE_WRITE|
                        IB_ACCESS_REMOTE_READ;
         ret = 0;
         break;
     default:
         ret = -EINVAL;
         break;
     }
     spin_unlock_irqrestore(&cm_id_priv->lock, flags);
     return ret;
 }
 
 static int iwcm_init_qp_rts_attr(struct iwcm_id_private *cm_id_priv,
                   struct ib_qp_attr *qp_attr,
                   int *qp_attr_mask)
 {
     unsigned long flags;
     int ret;
 
     spin_lock_irqsave(&cm_id_priv->lock, flags);
     switch (cm_id_priv->state) {
     case IW_CM_STATE_IDLE:
     case IW_CM_STATE_CONN_SENT:
     case IW_CM_STATE_CONN_RECV:
     case IW_CM_STATE_ESTABLISHED:
         *qp_attr_mask = 0;
         ret = 0;
         break;
     default:
         ret = -EINVAL;
         break;
     }
     spin_unlock_irqrestore(&cm_id_priv->lock, flags);
     return ret;
 }
 
 int iw_cm_init_qp_attr(struct iw_cm_id *cm_id,
                struct ib_qp_attr *qp_attr,
                int *qp_attr_mask)
 {
     struct iwcm_id_private *cm_id_priv;
     int ret;
 
     cm_id_priv = container_of(cm_id, struct iwcm_id_private, id);
     switch (qp_attr->qp_state) {
     case IB_QPS_INIT:
     case IB_QPS_RTR:
         ret = iwcm_init_qp_init_attr(cm_id_priv,
                          qp_attr, qp_attr_mask);
         break;
     case IB_QPS_RTS:
         ret = iwcm_init_qp_rts_attr(cm_id_priv,
                         qp_attr, qp_attr_mask);
         break;
     default:
         ret = -EINVAL;
         break;
     }
     return ret;
 }
 EXPORT_SYMBOL(iw_cm_init_qp_attr);
 
 static int __init iw_cm_init(void)
 {
     int ret;
 
     ret = iwpm_init(RDMA_NL_IWCM);
     if (ret)
         return ret;
 
     iwcm_wq = alloc_ordered_workqueue("iw_cm_wq", 0);
     if (!iwcm_wq)
         goto err_alloc;
 
     iwcm_ctl_table_hdr = register_net_sysctl(&init_net, "net/iw_cm",
                          iwcm_ctl_table);
     if (!iwcm_ctl_table_hdr) {
         pr_err("iw_cm: couldn't register sysctl paths\n");
         goto err_sysctl;
     }
 
     rdma_nl_register(RDMA_NL_IWCM, iwcm_nl_cb_table);
     return 0;
 
 err_sysctl:
     destroy_workqueue(iwcm_wq);
 err_alloc:
     iwpm_exit(RDMA_NL_IWCM);
     return -ENOMEM;
 }
 
 static void __exit iw_cm_cleanup(void)
 {
     rdma_nl_unregister(RDMA_NL_IWCM);
     unregister_net_sysctl_table(iwcm_ctl_table_hdr);
     destroy_workqueue(iwcm_wq);
     iwpm_exit(RDMA_NL_IWCM);
 }
 
 MODULE_ALIAS_RDMA_NETLINK(RDMA_NL_IWCM, 2);
 
 module_init(iw_cm_init);
 module_exit(iw_cm_cleanup);

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