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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-only
 /*
  * Copyright (c) 2009, Microsoft Corporation.
  *
  * Authors:
  *   Haiyang Zhang <haiyangz@microsoft.com>
  *   Hank Janssen  <hjanssen@microsoft.com>
  */
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 
 #include <linux/kernel.h>
 #include <linux/interrupt.h>
 #include <linux/sched.h>
 #include <linux/wait.h>
 #include <linux/mm.h>
 #include <linux/slab.h>
 #include <linux/list.h>
 #include <linux/module.h>
 #include <linux/completion.h>
 #include <linux/delay.h>
 #include <linux/cpu.h>
 #include <linux/hyperv.h>
 #include <asm/mshyperv.h>
 #include <linux/sched/isolation.h>
 
 #include "hyperv_vmbus.h"
 
 static void init_vp_index(struct vmbus_channel *channel);
 
 const struct vmbus_device vmbus_devs[] = {
     /* IDE */
     { .dev_type = HV_IDE,
       HV_IDE_GUID,
       .perf_device = true,
       .allowed_in_isolated = false,
     },
 
     /* SCSI */
     { .dev_type = HV_SCSI,
       HV_SCSI_GUID,
       .perf_device = true,
       .allowed_in_isolated = true,
     },
 
     /* Fibre Channel */
     { .dev_type = HV_FC,
       HV_SYNTHFC_GUID,
       .perf_device = true,
       .allowed_in_isolated = false,
     },
 
     /* Synthetic NIC */
     { .dev_type = HV_NIC,
       HV_NIC_GUID,
       .perf_device = true,
       .allowed_in_isolated = true,
     },
 
     /* Network Direct */
     { .dev_type = HV_ND,
       HV_ND_GUID,
       .perf_device = true,
       .allowed_in_isolated = false,
     },
 
     /* PCIE */
     { .dev_type = HV_PCIE,
       HV_PCIE_GUID,
       .perf_device = false,
       .allowed_in_isolated = false,
     },
 
     /* Synthetic Frame Buffer */
     { .dev_type = HV_FB,
       HV_SYNTHVID_GUID,
       .perf_device = false,
       .allowed_in_isolated = false,
     },
 
     /* Synthetic Keyboard */
     { .dev_type = HV_KBD,
       HV_KBD_GUID,
       .perf_device = false,
       .allowed_in_isolated = false,
     },
 
     /* Synthetic MOUSE */
     { .dev_type = HV_MOUSE,
       HV_MOUSE_GUID,
       .perf_device = false,
       .allowed_in_isolated = false,
     },
 
     /* KVP */
     { .dev_type = HV_KVP,
       HV_KVP_GUID,
       .perf_device = false,
       .allowed_in_isolated = false,
     },
 
     /* Time Synch */
     { .dev_type = HV_TS,
       HV_TS_GUID,
       .perf_device = false,
       .allowed_in_isolated = true,
     },
 
     /* Heartbeat */
     { .dev_type = HV_HB,
       HV_HEART_BEAT_GUID,
       .perf_device = false,
       .allowed_in_isolated = true,
     },
 
     /* Shutdown */
     { .dev_type = HV_SHUTDOWN,
       HV_SHUTDOWN_GUID,
       .perf_device = false,
       .allowed_in_isolated = true,
     },
 
     /* File copy */
     { .dev_type = HV_FCOPY,
       HV_FCOPY_GUID,
       .perf_device = false,
       .allowed_in_isolated = false,
     },
 
     /* Backup */
     { .dev_type = HV_BACKUP,
       HV_VSS_GUID,
       .perf_device = false,
       .allowed_in_isolated = false,
     },
 
     /* Dynamic Memory */
     { .dev_type = HV_DM,
       HV_DM_GUID,
       .perf_device = false,
       .allowed_in_isolated = false,
     },
 
     /* Unknown GUID */
     { .dev_type = HV_UNKNOWN,
       .perf_device = false,
       .allowed_in_isolated = false,
     },
 };
 
 static const struct {
     guid_t guid;
 } vmbus_unsupported_devs[] = {
     { HV_AVMA1_GUID },
     { HV_AVMA2_GUID },
     { HV_RDV_GUID   },
     { HV_IMC_GUID   },
 };
 
 /*
  * The rescinded channel may be blocked waiting for a response from the host;
  * take care of that.
  */
 static void vmbus_rescind_cleanup(struct vmbus_channel *channel)
 {
     struct vmbus_channel_msginfo *msginfo;
     unsigned long flags;
 
 
     spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
     channel->rescind = true;
     list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
                 msglistentry) {
 
         if (msginfo->waiting_channel == channel) {
             complete(&msginfo->waitevent);
             break;
         }
     }
     spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 }
 
 static bool is_unsupported_vmbus_devs(const guid_t *guid)
 {
     int i;
 
     for (i = 0; i < ARRAY_SIZE(vmbus_unsupported_devs); i++)
         if (guid_equal(guid, &vmbus_unsupported_devs[i].guid))
             return true;
     return false;
 }
 
 static u16 hv_get_dev_type(const struct vmbus_channel *channel)
 {
     const guid_t *guid = &channel->offermsg.offer.if_type;
     u16 i;
 
     if (is_hvsock_channel(channel) || is_unsupported_vmbus_devs(guid))
         return HV_UNKNOWN;
 
     for (i = HV_IDE; i < HV_UNKNOWN; i++) {
         if (guid_equal(guid, &vmbus_devs[i].guid))
             return i;
     }
     pr_info("Unknown GUID: %pUl\n", guid);
     return i;
 }
 
 /**
  * vmbus_prep_negotiate_resp() - Create default response for Negotiate message
  * @icmsghdrp: Pointer to msg header structure
  * @buf: Raw buffer channel data
  * @buflen: Length of the raw buffer channel data.
  * @fw_version: The framework versions we can support.
  * @fw_vercnt: The size of @fw_version.
  * @srv_version: The service versions we can support.
  * @srv_vercnt: The size of @srv_version.
  * @nego_fw_version: The selected framework version.
  * @nego_srv_version: The selected service version.
  *
  * Note: Versions are given in decreasing order.
  *
  * Set up and fill in default negotiate response message.
  * Mainly used by Hyper-V drivers.
  */
 bool vmbus_prep_negotiate_resp(struct icmsg_hdr *icmsghdrp, u8 *buf,
                 u32 buflen, const int *fw_version, int fw_vercnt,
                 const int *srv_version, int srv_vercnt,
                 int *nego_fw_version, int *nego_srv_version)
 {
     int icframe_major, icframe_minor;
     int icmsg_major, icmsg_minor;
     int fw_major, fw_minor;
     int srv_major, srv_minor;
     int i, j;
     bool found_match = false;
     struct icmsg_negotiate *negop;
 
     /* Check that there's enough space for icframe_vercnt, icmsg_vercnt */
     if (buflen < ICMSG_HDR + offsetof(struct icmsg_negotiate, reserved)) {
         pr_err_ratelimited("Invalid icmsg negotiate\n");
         return false;
     }
 
     icmsghdrp->icmsgsize = 0x10;
     negop = (struct icmsg_negotiate *)&buf[ICMSG_HDR];
 
     icframe_major = negop->icframe_vercnt;
     icframe_minor = 0;
 
     icmsg_major = negop->icmsg_vercnt;
     icmsg_minor = 0;
 
     /* Validate negop packet */
     if (icframe_major > IC_VERSION_NEGOTIATION_MAX_VER_COUNT ||
         icmsg_major > IC_VERSION_NEGOTIATION_MAX_VER_COUNT ||
         ICMSG_NEGOTIATE_PKT_SIZE(icframe_major, icmsg_major) > buflen) {
         pr_err_ratelimited("Invalid icmsg negotiate - icframe_major: %u, icmsg_major: %u\n",
                    icframe_major, icmsg_major);
         goto fw_error;
     }
 
     /*
      * Select the framework version number we will
      * support.
      */
 
     for (i = 0; i < fw_vercnt; i++) {
         fw_major = (fw_version[i] >> 16);
         fw_minor = (fw_version[i] & 0xFFFF);
 
         for (j = 0; j < negop->icframe_vercnt; j++) {
             if ((negop->icversion_data[j].major == fw_major) &&
                 (negop->icversion_data[j].minor == fw_minor)) {
                 icframe_major = negop->icversion_data[j].major;
                 icframe_minor = negop->icversion_data[j].minor;
                 found_match = true;
                 break;
             }
         }
 
         if (found_match)
             break;
     }
 
     if (!found_match)
         goto fw_error;
 
     found_match = false;
 
     for (i = 0; i < srv_vercnt; i++) {
         srv_major = (srv_version[i] >> 16);
         srv_minor = (srv_version[i] & 0xFFFF);
 
         for (j = negop->icframe_vercnt;
             (j < negop->icframe_vercnt + negop->icmsg_vercnt);
             j++) {
 
             if ((negop->icversion_data[j].major == srv_major) &&
                 (negop->icversion_data[j].minor == srv_minor)) {
 
                 icmsg_major = negop->icversion_data[j].major;
                 icmsg_minor = negop->icversion_data[j].minor;
                 found_match = true;
                 break;
             }
         }
 
         if (found_match)
             break;
     }
 
     /*
      * Respond with the framework and service
      * version numbers we can support.
      */
 
 fw_error:
     if (!found_match) {
         negop->icframe_vercnt = 0;
         negop->icmsg_vercnt = 0;
     } else {
         negop->icframe_vercnt = 1;
         negop->icmsg_vercnt = 1;
     }
 
     if (nego_fw_version)
         *nego_fw_version = (icframe_major << 16) | icframe_minor;
 
     if (nego_srv_version)
         *nego_srv_version = (icmsg_major << 16) | icmsg_minor;
 
     negop->icversion_data[0].major = icframe_major;
     negop->icversion_data[0].minor = icframe_minor;
     negop->icversion_data[1].major = icmsg_major;
     negop->icversion_data[1].minor = icmsg_minor;
     return found_match;
 }
 EXPORT_SYMBOL_GPL(vmbus_prep_negotiate_resp);
 
 /*
  * alloc_channel - Allocate and initialize a vmbus channel object
  */
 static struct vmbus_channel *alloc_channel(void)
 {
     struct vmbus_channel *channel;
 
     channel = kzalloc(sizeof(*channel), GFP_ATOMIC);
     if (!channel)
         return NULL;
 
     spin_lock_init(&channel->sched_lock);
     init_completion(&channel->rescind_event);
 
     INIT_LIST_HEAD(&channel->sc_list);
 
     tasklet_init(&channel->callback_event,
              vmbus_on_event, (unsigned long)channel);
 
     hv_ringbuffer_pre_init(channel);
 
     return channel;
 }
 
 /*
  * free_channel - Release the resources used by the vmbus channel object
  */
 static void free_channel(struct vmbus_channel *channel)
 {
     tasklet_kill(&channel->callback_event);
     vmbus_remove_channel_attr_group(channel);
 
     kobject_put(&channel->kobj);
 }
 
 void vmbus_channel_map_relid(struct vmbus_channel *channel)
 {
     if (WARN_ON(channel->offermsg.child_relid >= MAX_CHANNEL_RELIDS))
         return;
     /*
      * The mapping of the channel's relid is visible from the CPUs that
      * execute vmbus_chan_sched() by the time that vmbus_chan_sched() will
      * execute:
      *
      *  (a) In the "normal (i.e., not resuming from hibernation)" path,
      *      the full barrier in virt_store_mb() guarantees that the store
      *      is propagated to all CPUs before the add_channel_work work
      *      is queued.  In turn, add_channel_work is queued before the
      *      channel's ring buffer is allocated/initialized and the
      *      OPENCHANNEL message for the channel is sent in vmbus_open().
      *      Hyper-V won't start sending the interrupts for the channel
      *      before the OPENCHANNEL message is acked.  The memory barrier
      *      in vmbus_chan_sched() -> sync_test_and_clear_bit() ensures
      *      that vmbus_chan_sched() must find the channel's relid in
      *      recv_int_page before retrieving the channel pointer from the
      *      array of channels.
      *
      *  (b) In the "resuming from hibernation" path, the virt_store_mb()
      *      guarantees that the store is propagated to all CPUs before
      *      the VMBus connection is marked as ready for the resume event
      *      (cf. check_ready_for_resume_event()).  The interrupt handler
      *      of the VMBus driver and vmbus_chan_sched() can not run before
      *      vmbus_bus_resume() has completed execution (cf. resume_noirq).
      */
     virt_store_mb(
         vmbus_connection.channels[channel->offermsg.child_relid],
         channel);
 }
 
 void vmbus_channel_unmap_relid(struct vmbus_channel *channel)
 {
     if (WARN_ON(channel->offermsg.child_relid >= MAX_CHANNEL_RELIDS))
         return;
     WRITE_ONCE(
         vmbus_connection.channels[channel->offermsg.child_relid],
         NULL);
 }
 
 static void vmbus_release_relid(u32 relid)
 {
     struct vmbus_channel_relid_released msg;
     int ret;
 
     memset(&msg, 0, sizeof(struct vmbus_channel_relid_released));
     msg.child_relid = relid;
     msg.header.msgtype = CHANNELMSG_RELID_RELEASED;
     ret = vmbus_post_msg(&msg, sizeof(struct vmbus_channel_relid_released),
                  true);
 
     trace_vmbus_release_relid(&msg, ret);
 }
 
 void hv_process_channel_removal(struct vmbus_channel *channel)
 {
     lockdep_assert_held(&vmbus_connection.channel_mutex);
     BUG_ON(!channel->rescind);
 
     /*
      * hv_process_channel_removal() could find INVALID_RELID only for
      * hv_sock channels.  See the inline comments in vmbus_onoffer().
      */
     WARN_ON(channel->offermsg.child_relid == INVALID_RELID &&
         !is_hvsock_channel(channel));
 
     /*
      * Upon suspend, an in-use hv_sock channel is removed from the array of
      * channels and the relid is invalidated.  After hibernation, when the
      * user-space application destroys the channel, it's unnecessary and
      * unsafe to remove the channel from the array of channels.  See also
      * the inline comments before the call of vmbus_release_relid() below.
      */
     if (channel->offermsg.child_relid != INVALID_RELID)
         vmbus_channel_unmap_relid(channel);
 
     if (channel->primary_channel == NULL)
         list_del(&channel->listentry);
     else
         list_del(&channel->sc_list);
 
     /*
      * If this is a "perf" channel, updates the hv_numa_map[] masks so that
      * init_vp_index() can (re-)use the CPU.
      */
     if (hv_is_perf_channel(channel))
         hv_clear_allocated_cpu(channel->target_cpu);
 
     /*
      * Upon suspend, an in-use hv_sock channel is marked as "rescinded" and
      * the relid is invalidated; after hibernation, when the user-space app
      * destroys the channel, the relid is INVALID_RELID, and in this case
      * it's unnecessary and unsafe to release the old relid, since the same
      * relid can refer to a completely different channel now.
      */
     if (channel->offermsg.child_relid != INVALID_RELID)
         vmbus_release_relid(channel->offermsg.child_relid);
 
     free_channel(channel);
 }
 
 void vmbus_free_channels(void)
 {
     struct vmbus_channel *channel, *tmp;
 
     list_for_each_entry_safe(channel, tmp, &vmbus_connection.chn_list,
         listentry) {
         /* hv_process_channel_removal() needs this */
         channel->rescind = true;
 
         vmbus_device_unregister(channel->device_obj);
     }
 }
 
 /* Note: the function can run concurrently for primary/sub channels. */
 static void vmbus_add_channel_work(struct work_struct *work)
 {
     struct vmbus_channel *newchannel =
         container_of(work, struct vmbus_channel, add_channel_work);
     struct vmbus_channel *primary_channel = newchannel->primary_channel;
     int ret;
 
     /*
      * This state is used to indicate a successful open
      * so that when we do close the channel normally, we
      * can cleanup properly.
      */
     newchannel->state = CHANNEL_OPEN_STATE;
 
     if (primary_channel != NULL) {
         /* newchannel is a sub-channel. */
         struct hv_device *dev = primary_channel->device_obj;
 
         if (vmbus_add_channel_kobj(dev, newchannel))
             goto err_deq_chan;
 
         if (primary_channel->sc_creation_callback != NULL)
             primary_channel->sc_creation_callback(newchannel);
 
         newchannel->probe_done = true;
         return;
     }
 
     /*
      * Start the process of binding the primary channel to the driver
      */
     newchannel->device_obj = vmbus_device_create(
         &newchannel->offermsg.offer.if_type,
         &newchannel->offermsg.offer.if_instance,
         newchannel);
     if (!newchannel->device_obj)
         goto err_deq_chan;
 
     newchannel->device_obj->device_id = newchannel->device_id;
     /*
      * Add the new device to the bus. This will kick off device-driver
      * binding which eventually invokes the device driver's AddDevice()
      * method.
      */
     ret = vmbus_device_register(newchannel->device_obj);
 
     if (ret != 0) {
         pr_err("unable to add child device object (relid %d)\n",
             newchannel->offermsg.child_relid);
         kfree(newchannel->device_obj);
         goto err_deq_chan;
     }
 
     newchannel->probe_done = true;
     return;
 
 err_deq_chan:
     mutex_lock(&vmbus_connection.channel_mutex);
 
     /*
      * We need to set the flag, otherwise
      * vmbus_onoffer_rescind() can be blocked.
      */
     newchannel->probe_done = true;
 
     if (primary_channel == NULL)
         list_del(&newchannel->listentry);
     else
         list_del(&newchannel->sc_list);
 
     /* vmbus_process_offer() has mapped the channel. */
     vmbus_channel_unmap_relid(newchannel);
 
     mutex_unlock(&vmbus_connection.channel_mutex);
 
     vmbus_release_relid(newchannel->offermsg.child_relid);
 
     free_channel(newchannel);
 }
 
 /*
  * vmbus_process_offer - Process the offer by creating a channel/device
  * associated with this offer
  */
 static void vmbus_process_offer(struct vmbus_channel *newchannel)
 {
     struct vmbus_channel *channel;
     struct workqueue_struct *wq;
     bool fnew = true;
 
     /*
      * Synchronize vmbus_process_offer() and CPU hotplugging:
      *
      * CPU1             CPU2
      *
      * [vmbus_process_offer()]  [Hot removal of the CPU]
      *
      * CPU_READ_LOCK        CPUS_WRITE_LOCK
      * LOAD cpu_online_mask     SEARCH chn_list
      * STORE target_cpu     LOAD target_cpu
      * INSERT chn_list      STORE cpu_online_mask
      * CPUS_READ_UNLOCK     CPUS_WRITE_UNLOCK
      *
      * Forbids: CPU1's LOAD from *not* seing CPU2's STORE &&
      *              CPU2's SEARCH from *not* seeing CPU1's INSERT
      *
      * Forbids: CPU2's SEARCH from seeing CPU1's INSERT &&
      *              CPU2's LOAD from *not* seing CPU1's STORE
      */
     cpus_read_lock();
 
     /*
      * Serializes the modifications of the chn_list list as well as
      * the accesses to next_numa_node_id in init_vp_index().
      */
     mutex_lock(&vmbus_connection.channel_mutex);
 
     list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) {
         if (guid_equal(&channel->offermsg.offer.if_type,
                    &newchannel->offermsg.offer.if_type) &&
             guid_equal(&channel->offermsg.offer.if_instance,
                    &newchannel->offermsg.offer.if_instance)) {
             fnew = false;
             newchannel->primary_channel = channel;
             break;
         }
     }
 
     init_vp_index(newchannel);
 
     /* Remember the channels that should be cleaned up upon suspend. */
     if (is_hvsock_channel(newchannel) || is_sub_channel(newchannel))
         atomic_inc(&vmbus_connection.nr_chan_close_on_suspend);
 
     /*
      * Now that we have acquired the channel_mutex,
      * we can release the potentially racing rescind thread.
      */
     atomic_dec(&vmbus_connection.offer_in_progress);
 
     if (fnew) {
         list_add_tail(&newchannel->listentry,
                   &vmbus_connection.chn_list);
     } else {
         /*
          * Check to see if this is a valid sub-channel.
          */
         if (newchannel->offermsg.offer.sub_channel_index == 0) {
             mutex_unlock(&vmbus_connection.channel_mutex);
             cpus_read_unlock();
             /*
              * Don't call free_channel(), because newchannel->kobj
              * is not initialized yet.
              */
             kfree(newchannel);
             WARN_ON_ONCE(1);
             return;
         }
         /*
          * Process the sub-channel.
          */
         list_add_tail(&newchannel->sc_list, &channel->sc_list);
     }
 
     vmbus_channel_map_relid(newchannel);
 
     mutex_unlock(&vmbus_connection.channel_mutex);
     cpus_read_unlock();
 
     /*
      * vmbus_process_offer() mustn't call channel->sc_creation_callback()
      * directly for sub-channels, because sc_creation_callback() ->
      * vmbus_open() may never get the host's response to the
      * OPEN_CHANNEL message (the host may rescind a channel at any time,
      * e.g. in the case of hot removing a NIC), and vmbus_onoffer_rescind()
      * may not wake up the vmbus_open() as it's blocked due to a non-zero
      * vmbus_connection.offer_in_progress, and finally we have a deadlock.
      *
      * The above is also true for primary channels, if the related device
      * drivers use sync probing mode by default.
      *
      * And, usually the handling of primary channels and sub-channels can
      * depend on each other, so we should offload them to different
      * workqueues to avoid possible deadlock, e.g. in sync-probing mode,
      * NIC1's netvsc_subchan_work() can race with NIC2's netvsc_probe() ->
      * rtnl_lock(), and causes deadlock: the former gets the rtnl_lock
      * and waits for all the sub-channels to appear, but the latter
      * can't get the rtnl_lock and this blocks the handling of
      * sub-channels.
      */
     INIT_WORK(&newchannel->add_channel_work, vmbus_add_channel_work);
     wq = fnew ? vmbus_connection.handle_primary_chan_wq :
             vmbus_connection.handle_sub_chan_wq;
     queue_work(wq, &newchannel->add_channel_work);
 }
 
 /*
  * Check if CPUs used by other channels of the same device.
  * It should only be called by init_vp_index().
  */
 static bool hv_cpuself_used(u32 cpu, struct vmbus_channel *chn)
 {
     struct vmbus_channel *primary = chn->primary_channel;
     struct vmbus_channel *sc;
 
     lockdep_assert_held(&vmbus_connection.channel_mutex);
 
     if (!primary)
         return false;
 
     if (primary->target_cpu == cpu)
         return true;
 
     list_for_each_entry(sc, &primary->sc_list, sc_list)
         if (sc != chn && sc->target_cpu == cpu)
             return true;
 
     return false;
 }
 
 /*
  * We use this state to statically distribute the channel interrupt load.
  */
 static int next_numa_node_id;
 
 /*
  * We can statically distribute the incoming channel interrupt load
  * by binding a channel to VCPU.
  *
  * For non-performance critical channels we assign the VMBUS_CONNECT_CPU.
  * Performance critical channels will be distributed evenly among all
  * the available NUMA nodes.  Once the node is assigned, we will assign
  * the CPU based on a simple round robin scheme.
  */
 static void init_vp_index(struct vmbus_channel *channel)
 {
     bool perf_chn = hv_is_perf_channel(channel);
     u32 i, ncpu = num_online_cpus();
     cpumask_var_t available_mask;
     struct cpumask *allocated_mask;
     const struct cpumask *hk_mask = housekeeping_cpumask(HK_TYPE_MANAGED_IRQ);
     u32 target_cpu;
     int numa_node;
 
     if (!perf_chn ||
         !alloc_cpumask_var(&available_mask, GFP_KERNEL) ||
         cpumask_empty(hk_mask)) {
         /*
          * If the channel is not a performance critical
          * channel, bind it to VMBUS_CONNECT_CPU.
          * In case alloc_cpumask_var() fails, bind it to
          * VMBUS_CONNECT_CPU.
          * If all the cpus are isolated, bind it to
          * VMBUS_CONNECT_CPU.
          */
         channel->target_cpu = VMBUS_CONNECT_CPU;
         if (perf_chn)
             hv_set_allocated_cpu(VMBUS_CONNECT_CPU);
         return;
     }
 
     for (i = 1; i <= ncpu + 1; i++) {
         while (true) {
             numa_node = next_numa_node_id++;
             if (numa_node == nr_node_ids) {
                 next_numa_node_id = 0;
                 continue;
             }
             if (cpumask_empty(cpumask_of_node(numa_node)))
                 continue;
             break;
         }
         allocated_mask = &hv_context.hv_numa_map[numa_node];
 
 retry:
         cpumask_xor(available_mask, allocated_mask, cpumask_of_node(numa_node));
         cpumask_and(available_mask, available_mask, hk_mask);
 
         if (cpumask_empty(available_mask)) {
             /*
              * We have cycled through all the CPUs in the node;
              * reset the allocated map.
              */
             cpumask_clear(allocated_mask);
             goto retry;
         }
 
         target_cpu = cpumask_first(available_mask);
         cpumask_set_cpu(target_cpu, allocated_mask);
 
         if (channel->offermsg.offer.sub_channel_index >= ncpu ||
             i > ncpu || !hv_cpuself_used(target_cpu, channel))
             break;
     }
 
     channel->target_cpu = target_cpu;
 
     free_cpumask_var(available_mask);
 }
 
 #define UNLOAD_DELAY_UNIT_MS    10      /* 10 milliseconds */
 #define UNLOAD_WAIT_MS      (100*1000)  /* 100 seconds */
 #define UNLOAD_WAIT_LOOPS   (UNLOAD_WAIT_MS/UNLOAD_DELAY_UNIT_MS)
 #define UNLOAD_MSG_MS       (5*1000)    /* Every 5 seconds */
 #define UNLOAD_MSG_LOOPS    (UNLOAD_MSG_MS/UNLOAD_DELAY_UNIT_MS)
 
 static void vmbus_wait_for_unload(void)
 {
     int cpu;
     void *page_addr;
     struct hv_message *msg;
     struct vmbus_channel_message_header *hdr;
     u32 message_type, i;
 
     /*
      * CHANNELMSG_UNLOAD_RESPONSE is always delivered to the CPU which was
      * used for initial contact or to CPU0 depending on host version. When
      * we're crashing on a different CPU let's hope that IRQ handler on
      * the cpu which receives CHANNELMSG_UNLOAD_RESPONSE is still
      * functional and vmbus_unload_response() will complete
      * vmbus_connection.unload_event. If not, the last thing we can do is
      * read message pages for all CPUs directly.
      *
      * Wait up to 100 seconds since an Azure host must writeback any dirty
      * data in its disk cache before the VMbus UNLOAD request will
      * complete. This flushing has been empirically observed to take up
      * to 50 seconds in cases with a lot of dirty data, so allow additional
      * leeway and for inaccuracies in mdelay(). But eventually time out so
      * that the panic path can't get hung forever in case the response
      * message isn't seen.
      */
     for (i = 1; i <= UNLOAD_WAIT_LOOPS; i++) {
         if (completion_done(&vmbus_connection.unload_event))
             goto completed;
 
         for_each_online_cpu(cpu) {
             struct hv_per_cpu_context *hv_cpu
                 = per_cpu_ptr(hv_context.cpu_context, cpu);
 
             page_addr = hv_cpu->synic_message_page;
             msg = (struct hv_message *)page_addr
                 + VMBUS_MESSAGE_SINT;
 
             message_type = READ_ONCE(msg->header.message_type);
             if (message_type == HVMSG_NONE)
                 continue;
 
             hdr = (struct vmbus_channel_message_header *)
                 msg->u.payload;
 
             if (hdr->msgtype == CHANNELMSG_UNLOAD_RESPONSE)
                 complete(&vmbus_connection.unload_event);
 
             vmbus_signal_eom(msg, message_type);
         }
 
         /*
          * Give a notice periodically so someone watching the
          * serial output won't think it is completely hung.
          */
         if (!(i % UNLOAD_MSG_LOOPS))
             pr_notice("Waiting for VMBus UNLOAD to complete\n");
 
         mdelay(UNLOAD_DELAY_UNIT_MS);
     }
     pr_err("Continuing even though VMBus UNLOAD did not complete\n");
 
 completed:
     /*
      * We're crashing and already got the UNLOAD_RESPONSE, cleanup all
      * maybe-pending messages on all CPUs to be able to receive new
      * messages after we reconnect.
      */
     for_each_online_cpu(cpu) {
         struct hv_per_cpu_context *hv_cpu
             = per_cpu_ptr(hv_context.cpu_context, cpu);
 
         page_addr = hv_cpu->synic_message_page;
         msg = (struct hv_message *)page_addr + VMBUS_MESSAGE_SINT;
         msg->header.message_type = HVMSG_NONE;
     }
 }
 
 /*
  * vmbus_unload_response - Handler for the unload response.
  */
 static void vmbus_unload_response(struct vmbus_channel_message_header *hdr)
 {
     /*
      * This is a global event; just wakeup the waiting thread.
      * Once we successfully unload, we can cleanup the monitor state.
      *
      * NB.  A malicious or compromised Hyper-V could send a spurious
      * message of type CHANNELMSG_UNLOAD_RESPONSE, and trigger a call
      * of the complete() below.  Make sure that unload_event has been
      * initialized by the time this complete() is executed.
      */
     complete(&vmbus_connection.unload_event);
 }
 
 void vmbus_initiate_unload(bool crash)
 {
     struct vmbus_channel_message_header hdr;
 
     if (xchg(&vmbus_connection.conn_state, DISCONNECTED) == DISCONNECTED)
         return;
 
     /* Pre-Win2012R2 hosts don't support reconnect */
     if (vmbus_proto_version < VERSION_WIN8_1)
         return;
 
     reinit_completion(&vmbus_connection.unload_event);
     memset(&hdr, 0, sizeof(struct vmbus_channel_message_header));
     hdr.msgtype = CHANNELMSG_UNLOAD;
     vmbus_post_msg(&hdr, sizeof(struct vmbus_channel_message_header),
                !crash);
 
     /*
      * vmbus_initiate_unload() is also called on crash and the crash can be
      * happening in an interrupt context, where scheduling is impossible.
      */
     if (!crash)
         wait_for_completion(&vmbus_connection.unload_event);
     else
         vmbus_wait_for_unload();
 }
 
 static void check_ready_for_resume_event(void)
 {
     /*
      * If all the old primary channels have been fixed up, then it's safe
      * to resume.
      */
     if (atomic_dec_and_test(&vmbus_connection.nr_chan_fixup_on_resume))
         complete(&vmbus_connection.ready_for_resume_event);
 }
 
 static void vmbus_setup_channel_state(struct vmbus_channel *channel,
                       struct vmbus_channel_offer_channel *offer)
 {
     /*
      * Setup state for signalling the host.
      */
     channel->sig_event = VMBUS_EVENT_CONNECTION_ID;
 
     channel->is_dedicated_interrupt =
             (offer->is_dedicated_interrupt != 0);
     channel->sig_event = offer->connection_id;
 
     memcpy(&channel->offermsg, offer,
            sizeof(struct vmbus_channel_offer_channel));
     channel->monitor_grp = (u8)offer->monitorid / 32;
     channel->monitor_bit = (u8)offer->monitorid % 32;
     channel->device_id = hv_get_dev_type(channel);
 }
 
 /*
  * find_primary_channel_by_offer - Get the channel object given the new offer.
  * This is only used in the resume path of hibernation.
  */
 static struct vmbus_channel *
 find_primary_channel_by_offer(const struct vmbus_channel_offer_channel *offer)
 {
     struct vmbus_channel *channel = NULL, *iter;
     const guid_t *inst1, *inst2;
 
     /* Ignore sub-channel offers. */
     if (offer->offer.sub_channel_index != 0)
         return NULL;
 
     mutex_lock(&vmbus_connection.channel_mutex);
 
     list_for_each_entry(iter, &vmbus_connection.chn_list, listentry) {
         inst1 = &iter->offermsg.offer.if_instance;
         inst2 = &offer->offer.if_instance;
 
         if (guid_equal(inst1, inst2)) {
             channel = iter;
             break;
         }
     }
 
     mutex_unlock(&vmbus_connection.channel_mutex);
 
     return channel;
 }
 
 static bool vmbus_is_valid_offer(const struct vmbus_channel_offer_channel *offer)
 {
     const guid_t *guid = &offer->offer.if_type;
     u16 i;
 
     if (!hv_is_isolation_supported())
         return true;
 
     if (is_hvsock_offer(offer))
         return true;
 
     for (i = 0; i < ARRAY_SIZE(vmbus_devs); i++) {
         if (guid_equal(guid, &vmbus_devs[i].guid))
             return vmbus_devs[i].allowed_in_isolated;
     }
     return false;
 }
 
 /*
  * vmbus_onoffer - Handler for channel offers from vmbus in parent partition.
  *
  */
 static void vmbus_onoffer(struct vmbus_channel_message_header *hdr)
 {
     struct vmbus_channel_offer_channel *offer;
     struct vmbus_channel *oldchannel, *newchannel;
     size_t offer_sz;
 
     offer = (struct vmbus_channel_offer_channel *)hdr;
 
     trace_vmbus_onoffer(offer);
 
     if (!vmbus_is_valid_offer(offer)) {
         pr_err_ratelimited("Invalid offer %d from the host supporting isolation\n",
                    offer->child_relid);
         atomic_dec(&vmbus_connection.offer_in_progress);
         return;
     }
 
     oldchannel = find_primary_channel_by_offer(offer);
 
     if (oldchannel != NULL) {
         /*
          * We're resuming from hibernation: all the sub-channel and
          * hv_sock channels we had before the hibernation should have
          * been cleaned up, and now we must be seeing a re-offered
          * primary channel that we had before the hibernation.
          */
 
         /*
          * { Initially: channel relid = INVALID_RELID,
          *      channels[valid_relid] = NULL }
          *
          * CPU1                 CPU2
          *
          * [vmbus_onoffer()]            [vmbus_device_release()]
          *
          * LOCK channel_mutex           LOCK channel_mutex
          * STORE channel relid = valid_relid    LOAD r1 = channel relid
          * MAP_RELID channel            if (r1 != INVALID_RELID)
          * UNLOCK channel_mutex           UNMAP_RELID channel
          *                  UNLOCK channel_mutex
          *
          * Forbids: r1 == valid_relid &&
          *              channels[valid_relid] == channel
          *
          * Note.  r1 can be INVALID_RELID only for an hv_sock channel.
          * None of the hv_sock channels which were present before the
          * suspend are re-offered upon the resume.  See the WARN_ON()
          * in hv_process_channel_removal().
          */
         mutex_lock(&vmbus_connection.channel_mutex);
 
         atomic_dec(&vmbus_connection.offer_in_progress);
 
         WARN_ON(oldchannel->offermsg.child_relid != INVALID_RELID);
         /* Fix up the relid. */
         oldchannel->offermsg.child_relid = offer->child_relid;
 
         offer_sz = sizeof(*offer);
         if (memcmp(offer, &oldchannel->offermsg, offer_sz) != 0) {
             /*
              * This is not an error, since the host can also change
              * the other field(s) of the offer, e.g. on WS RS5
              * (Build 17763), the offer->connection_id of the
              * Mellanox VF vmbus device can change when the host
              * reoffers the device upon resume.
              */
             pr_debug("vmbus offer changed: relid=%d\n",
                  offer->child_relid);
 
             print_hex_dump_debug("Old vmbus offer: ",
                          DUMP_PREFIX_OFFSET, 16, 4,
                          &oldchannel->offermsg, offer_sz,
                          false);
             print_hex_dump_debug("New vmbus offer: ",
                          DUMP_PREFIX_OFFSET, 16, 4,
                          offer, offer_sz, false);
 
             /* Fix up the old channel. */
             vmbus_setup_channel_state(oldchannel, offer);
         }
 
         /* Add the channel back to the array of channels. */
         vmbus_channel_map_relid(oldchannel);
         check_ready_for_resume_event();
 
         mutex_unlock(&vmbus_connection.channel_mutex);
         return;
     }
 
     /* Allocate the channel object and save this offer. */
     newchannel = alloc_channel();
     if (!newchannel) {
         vmbus_release_relid(offer->child_relid);
         atomic_dec(&vmbus_connection.offer_in_progress);
         pr_err("Unable to allocate channel object\n");
         return;
     }
 
     vmbus_setup_channel_state(newchannel, offer);
 
     vmbus_process_offer(newchannel);
 }
 
 static void check_ready_for_suspend_event(void)
 {
     /*
      * If all the sub-channels or hv_sock channels have been cleaned up,
      * then it's safe to suspend.
      */
     if (atomic_dec_and_test(&vmbus_connection.nr_chan_close_on_suspend))
         complete(&vmbus_connection.ready_for_suspend_event);
 }
 
 /*
  * vmbus_onoffer_rescind - Rescind offer handler.
  *
  * We queue a work item to process this offer synchronously
  */
 static void vmbus_onoffer_rescind(struct vmbus_channel_message_header *hdr)
 {
     struct vmbus_channel_rescind_offer *rescind;
     struct vmbus_channel *channel;
     struct device *dev;
     bool clean_up_chan_for_suspend;
 
     rescind = (struct vmbus_channel_rescind_offer *)hdr;
 
     trace_vmbus_onoffer_rescind(rescind);
 
     /*
      * The offer msg and the corresponding rescind msg
      * from the host are guranteed to be ordered -
      * offer comes in first and then the rescind.
      * Since we process these events in work elements,
      * and with preemption, we may end up processing
      * the events out of order.  We rely on the synchronization
      * provided by offer_in_progress and by channel_mutex for
      * ordering these events:
      *
      * { Initially: offer_in_progress = 1 }
      *
      * CPU1             CPU2
      *
      * [vmbus_onoffer()]        [vmbus_onoffer_rescind()]
      *
      * LOCK channel_mutex       WAIT_ON offer_in_progress == 0
      * DECREMENT offer_in_progress  LOCK channel_mutex
      * STORE channels[]     LOAD channels[]
      * UNLOCK channel_mutex     UNLOCK channel_mutex
      *
      * Forbids: CPU2's LOAD from *not* seeing CPU1's STORE
      */
 
     while (atomic_read(&vmbus_connection.offer_in_progress) != 0) {
         /*
          * We wait here until any channel offer is currently
          * being processed.
          */
         msleep(1);
     }
 
     mutex_lock(&vmbus_connection.channel_mutex);
     channel = relid2channel(rescind->child_relid);
     if (channel != NULL) {
         /*
          * Guarantee that no other instance of vmbus_onoffer_rescind()
          * has got a reference to the channel object.  Synchronize on
          * &vmbus_connection.channel_mutex.
          */
         if (channel->rescind_ref) {
             mutex_unlock(&vmbus_connection.channel_mutex);
             return;
         }
         channel->rescind_ref = true;
     }
     mutex_unlock(&vmbus_connection.channel_mutex);
 
     if (channel == NULL) {
         /*
          * We failed in processing the offer message;
          * we would have cleaned up the relid in that
          * failure path.
          */
         return;
     }
 
     clean_up_chan_for_suspend = is_hvsock_channel(channel) ||
                     is_sub_channel(channel);
     /*
      * Before setting channel->rescind in vmbus_rescind_cleanup(), we
      * should make sure the channel callback is not running any more.
      */
     vmbus_reset_channel_cb(channel);
 
     /*
      * Now wait for offer handling to complete.
      */
     vmbus_rescind_cleanup(channel);
     while (READ_ONCE(channel->probe_done) == false) {
         /*
          * We wait here until any channel offer is currently
          * being processed.
          */
         msleep(1);
     }
 
     /*
      * At this point, the rescind handling can proceed safely.
      */
 
     if (channel->device_obj) {
         if (channel->chn_rescind_callback) {
             channel->chn_rescind_callback(channel);
 
             if (clean_up_chan_for_suspend)
                 check_ready_for_suspend_event();
 
             return;
         }
         /*
          * We will have to unregister this device from the
          * driver core.
          */
         dev = get_device(&channel->device_obj->device);
         if (dev) {
             vmbus_device_unregister(channel->device_obj);
             put_device(dev);
         }
     } else if (channel->primary_channel != NULL) {
         /*
          * Sub-channel is being rescinded. Following is the channel
          * close sequence when initiated from the driveri (refer to
          * vmbus_close() for details):
          * 1. Close all sub-channels first
          * 2. Then close the primary channel.
          */
         mutex_lock(&vmbus_connection.channel_mutex);
         if (channel->state == CHANNEL_OPEN_STATE) {
             /*
              * The channel is currently not open;
              * it is safe for us to cleanup the channel.
              */
             hv_process_channel_removal(channel);
         } else {
             complete(&channel->rescind_event);
         }
         mutex_unlock(&vmbus_connection.channel_mutex);
     }
 
     /* The "channel" may have been freed. Do not access it any longer. */
 
     if (clean_up_chan_for_suspend)
         check_ready_for_suspend_event();
 }
 
 void vmbus_hvsock_device_unregister(struct vmbus_channel *channel)
 {
     BUG_ON(!is_hvsock_channel(channel));
 
     /* We always get a rescind msg when a connection is closed. */
     while (!READ_ONCE(channel->probe_done) || !READ_ONCE(channel->rescind))
         msleep(1);
 
     vmbus_device_unregister(channel->device_obj);
 }
 EXPORT_SYMBOL_GPL(vmbus_hvsock_device_unregister);
 
 
 /*
  * vmbus_onoffers_delivered -
  * This is invoked when all offers have been delivered.
  *
  * Nothing to do here.
  */
 static void vmbus_onoffers_delivered(
             struct vmbus_channel_message_header *hdr)
 {
 }
 
 /*
  * vmbus_onopen_result - Open result handler.
  *
  * This is invoked when we received a response to our channel open request.
  * Find the matching request, copy the response and signal the requesting
  * thread.
  */
 static void vmbus_onopen_result(struct vmbus_channel_message_header *hdr)
 {
     struct vmbus_channel_open_result *result;
     struct vmbus_channel_msginfo *msginfo;
     struct vmbus_channel_message_header *requestheader;
     struct vmbus_channel_open_channel *openmsg;
     unsigned long flags;
 
     result = (struct vmbus_channel_open_result *)hdr;
 
     trace_vmbus_onopen_result(result);
 
     /*
      * Find the open msg, copy the result and signal/unblock the wait event
      */
     spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 
     list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
                 msglistentry) {
         requestheader =
             (struct vmbus_channel_message_header *)msginfo->msg;
 
         if (requestheader->msgtype == CHANNELMSG_OPENCHANNEL) {
             openmsg =
             (struct vmbus_channel_open_channel *)msginfo->msg;
             if (openmsg->child_relid == result->child_relid &&
                 openmsg->openid == result->openid) {
                 memcpy(&msginfo->response.open_result,
                        result,
                        sizeof(
                     struct vmbus_channel_open_result));
                 complete(&msginfo->waitevent);
                 break;
             }
         }
     }
     spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 }
 
 /*
  * vmbus_ongpadl_created - GPADL created handler.
  *
  * This is invoked when we received a response to our gpadl create request.
  * Find the matching request, copy the response and signal the requesting
  * thread.
  */
 static void vmbus_ongpadl_created(struct vmbus_channel_message_header *hdr)
 {
     struct vmbus_channel_gpadl_created *gpadlcreated;
     struct vmbus_channel_msginfo *msginfo;
     struct vmbus_channel_message_header *requestheader;
     struct vmbus_channel_gpadl_header *gpadlheader;
     unsigned long flags;
 
     gpadlcreated = (struct vmbus_channel_gpadl_created *)hdr;
 
     trace_vmbus_ongpadl_created(gpadlcreated);
 
     /*
      * Find the establish msg, copy the result and signal/unblock the wait
      * event
      */
     spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 
     list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
                 msglistentry) {
         requestheader =
             (struct vmbus_channel_message_header *)msginfo->msg;
 
         if (requestheader->msgtype == CHANNELMSG_GPADL_HEADER) {
             gpadlheader =
             (struct vmbus_channel_gpadl_header *)requestheader;
 
             if ((gpadlcreated->child_relid ==
                  gpadlheader->child_relid) &&
                 (gpadlcreated->gpadl == gpadlheader->gpadl)) {
                 memcpy(&msginfo->response.gpadl_created,
                        gpadlcreated,
                        sizeof(
                     struct vmbus_channel_gpadl_created));
                 complete(&msginfo->waitevent);
                 break;
             }
         }
     }
     spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 }
 
 /*
  * vmbus_onmodifychannel_response - Modify Channel response handler.
  *
  * This is invoked when we received a response to our channel modify request.
  * Find the matching request, copy the response and signal the requesting thread.
  */
 static void vmbus_onmodifychannel_response(struct vmbus_channel_message_header *hdr)
 {
     struct vmbus_channel_modifychannel_response *response;
     struct vmbus_channel_msginfo *msginfo;
     unsigned long flags;
 
     response = (struct vmbus_channel_modifychannel_response *)hdr;
 
     trace_vmbus_onmodifychannel_response(response);
 
     /*
      * Find the modify msg, copy the response and signal/unblock the wait event.
      */
     spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 
     list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list, msglistentry) {
         struct vmbus_channel_message_header *responseheader =
                 (struct vmbus_channel_message_header *)msginfo->msg;
 
         if (responseheader->msgtype == CHANNELMSG_MODIFYCHANNEL) {
             struct vmbus_channel_modifychannel *modifymsg;
 
             modifymsg = (struct vmbus_channel_modifychannel *)msginfo->msg;
             if (modifymsg->child_relid == response->child_relid) {
                 memcpy(&msginfo->response.modify_response, response,
                        sizeof(*response));
                 complete(&msginfo->waitevent);
                 break;
             }
         }
     }
     spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 }
 
 /*
  * vmbus_ongpadl_torndown - GPADL torndown handler.
  *
  * This is invoked when we received a response to our gpadl teardown request.
  * Find the matching request, copy the response and signal the requesting
  * thread.
  */
 static void vmbus_ongpadl_torndown(
             struct vmbus_channel_message_header *hdr)
 {
     struct vmbus_channel_gpadl_torndown *gpadl_torndown;
     struct vmbus_channel_msginfo *msginfo;
     struct vmbus_channel_message_header *requestheader;
     struct vmbus_channel_gpadl_teardown *gpadl_teardown;
     unsigned long flags;
 
     gpadl_torndown = (struct vmbus_channel_gpadl_torndown *)hdr;
 
     trace_vmbus_ongpadl_torndown(gpadl_torndown);
 
     /*
      * Find the open msg, copy the result and signal/unblock the wait event
      */
     spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 
     list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
                 msglistentry) {
         requestheader =
             (struct vmbus_channel_message_header *)msginfo->msg;
 
         if (requestheader->msgtype == CHANNELMSG_GPADL_TEARDOWN) {
             gpadl_teardown =
             (struct vmbus_channel_gpadl_teardown *)requestheader;
 
             if (gpadl_torndown->gpadl == gpadl_teardown->gpadl) {
                 memcpy(&msginfo->response.gpadl_torndown,
                        gpadl_torndown,
                        sizeof(
                     struct vmbus_channel_gpadl_torndown));
                 complete(&msginfo->waitevent);
                 break;
             }
         }
     }
     spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 }
 
 /*
  * vmbus_onversion_response - Version response handler
  *
  * This is invoked when we received a response to our initiate contact request.
  * Find the matching request, copy the response and signal the requesting
  * thread.
  */
 static void vmbus_onversion_response(
         struct vmbus_channel_message_header *hdr)
 {
     struct vmbus_channel_msginfo *msginfo;
     struct vmbus_channel_message_header *requestheader;
     struct vmbus_channel_version_response *version_response;
     unsigned long flags;
 
     version_response = (struct vmbus_channel_version_response *)hdr;
 
     trace_vmbus_onversion_response(version_response);
 
     spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 
     list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
                 msglistentry) {
         requestheader =
             (struct vmbus_channel_message_header *)msginfo->msg;
 
         if (requestheader->msgtype ==
             CHANNELMSG_INITIATE_CONTACT) {
             memcpy(&msginfo->response.version_response,
                   version_response,
                   sizeof(struct vmbus_channel_version_response));
             complete(&msginfo->waitevent);
         }
     }
     spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 }
 
 /* Channel message dispatch table */
 const struct vmbus_channel_message_table_entry
 channel_message_table[CHANNELMSG_COUNT] = {
     { CHANNELMSG_INVALID,           0, NULL, 0},
     { CHANNELMSG_OFFERCHANNEL,      0, vmbus_onoffer,
         sizeof(struct vmbus_channel_offer_channel)},
     { CHANNELMSG_RESCIND_CHANNELOFFER,  0, vmbus_onoffer_rescind,
         sizeof(struct vmbus_channel_rescind_offer) },
     { CHANNELMSG_REQUESTOFFERS,     0, NULL, 0},
     { CHANNELMSG_ALLOFFERS_DELIVERED,   1, vmbus_onoffers_delivered, 0},
     { CHANNELMSG_OPENCHANNEL,       0, NULL, 0},
     { CHANNELMSG_OPENCHANNEL_RESULT,    1, vmbus_onopen_result,
         sizeof(struct vmbus_channel_open_result)},
     { CHANNELMSG_CLOSECHANNEL,      0, NULL, 0},
     { CHANNELMSG_GPADL_HEADER,      0, NULL, 0},
     { CHANNELMSG_GPADL_BODY,        0, NULL, 0},
     { CHANNELMSG_GPADL_CREATED,     1, vmbus_ongpadl_created,
         sizeof(struct vmbus_channel_gpadl_created)},
     { CHANNELMSG_GPADL_TEARDOWN,        0, NULL, 0},
     { CHANNELMSG_GPADL_TORNDOWN,        1, vmbus_ongpadl_torndown,
         sizeof(struct vmbus_channel_gpadl_torndown) },
     { CHANNELMSG_RELID_RELEASED,        0, NULL, 0},
     { CHANNELMSG_INITIATE_CONTACT,      0, NULL, 0},
     { CHANNELMSG_VERSION_RESPONSE,      1, vmbus_onversion_response,
         sizeof(struct vmbus_channel_version_response)},
     { CHANNELMSG_UNLOAD,            0, NULL, 0},
     { CHANNELMSG_UNLOAD_RESPONSE,       1, vmbus_unload_response, 0},
     { CHANNELMSG_18,            0, NULL, 0},
     { CHANNELMSG_19,            0, NULL, 0},
     { CHANNELMSG_20,            0, NULL, 0},
     { CHANNELMSG_TL_CONNECT_REQUEST,    0, NULL, 0},
     { CHANNELMSG_MODIFYCHANNEL,     0, NULL, 0},
     { CHANNELMSG_TL_CONNECT_RESULT,     0, NULL, 0},
     { CHANNELMSG_MODIFYCHANNEL_RESPONSE,    1, vmbus_onmodifychannel_response,
         sizeof(struct vmbus_channel_modifychannel_response)},
 };
 
 /*
  * vmbus_onmessage - Handler for channel protocol messages.
  *
  * This is invoked in the vmbus worker thread context.
  */
 void vmbus_onmessage(struct vmbus_channel_message_header *hdr)
 {
     trace_vmbus_on_message(hdr);
 
     /*
      * vmbus_on_msg_dpc() makes sure the hdr->msgtype here can not go
      * out of bound and the message_handler pointer can not be NULL.
      */
     channel_message_table[hdr->msgtype].message_handler(hdr);
 }
 
 /*
  * vmbus_request_offers - Send a request to get all our pending offers.
  */
 int vmbus_request_offers(void)
 {
     struct vmbus_channel_message_header *msg;
     struct vmbus_channel_msginfo *msginfo;
     int ret;
 
     msginfo = kzalloc(sizeof(*msginfo) +
               sizeof(struct vmbus_channel_message_header),
               GFP_KERNEL);
     if (!msginfo)
         return -ENOMEM;
 
     msg = (struct vmbus_channel_message_header *)msginfo->msg;
 
     msg->msgtype = CHANNELMSG_REQUESTOFFERS;
 
     ret = vmbus_post_msg(msg, sizeof(struct vmbus_channel_message_header),
                  true);
 
     trace_vmbus_request_offers(ret);
 
     if (ret != 0) {
         pr_err("Unable to request offers - %d\n", ret);
 
         goto cleanup;
     }
 
 cleanup:
     kfree(msginfo);
 
     return ret;
 }
 
 void vmbus_set_sc_create_callback(struct vmbus_channel *primary_channel,
                 void (*sc_cr_cb)(struct vmbus_channel *new_sc))
 {
     primary_channel->sc_creation_callback = sc_cr_cb;
 }
 EXPORT_SYMBOL_GPL(vmbus_set_sc_create_callback);
 
 void vmbus_set_chn_rescind_callback(struct vmbus_channel *channel,
         void (*chn_rescind_cb)(struct vmbus_channel *))
 {
     channel->chn_rescind_callback = chn_rescind_cb;
 }
 EXPORT_SYMBOL_GPL(vmbus_set_chn_rescind_callback);

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