diff options
Diffstat (limited to 'drivers/hv/channel_mgmt.c')
| -rw-r--r-- | drivers/hv/channel_mgmt.c | 873 |
1 files changed, 873 insertions, 0 deletions
diff --git a/drivers/hv/channel_mgmt.c b/drivers/hv/channel_mgmt.c new file mode 100644 index 00000000000..ed9350d4276 --- /dev/null +++ b/drivers/hv/channel_mgmt.c @@ -0,0 +1,873 @@ +/* + * Copyright (c) 2009, Microsoft Corporation. + * + * This program is free software; you can redistribute it and/or modify it + * under the terms and conditions of the GNU General Public License, + * version 2, as published by the Free Software Foundation. + * + * This program is distributed in the hope it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for + * more details. + * + * You should have received a copy of the GNU General Public License along with + * this program; if not, write to the Free Software Foundation, Inc., 59 Temple + * Place - Suite 330, Boston, MA 02111-1307 USA. + * + * Authors: + * Haiyang Zhang <haiyangz@microsoft.com> + * Hank Janssen <hjanssen@microsoft.com> + */ +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include <linux/kernel.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/hyperv.h> + +#include "hyperv_vmbus.h" + +struct vmbus_channel_message_table_entry { + enum vmbus_channel_message_type message_type; + void (*message_handler)(struct vmbus_channel_message_header *msg); +}; + + +/** + * vmbus_prep_negotiate_resp() - Create default response for Hyper-V Negotiate message + * @icmsghdrp: Pointer to msg header structure + * @icmsg_negotiate: Pointer to negotiate message structure + * @buf: Raw buffer channel data + * + * @icmsghdrp is of type &struct icmsg_hdr. + * @negop is of type &struct icmsg_negotiate. + * Set up and fill in default negotiate response message. + * + * The fw_version specifies the framework version that + * we can support and srv_version specifies the service + * version we can support. + * + * Mainly used by Hyper-V drivers. + */ +bool vmbus_prep_negotiate_resp(struct icmsg_hdr *icmsghdrp, + struct icmsg_negotiate *negop, u8 *buf, + int fw_version, int srv_version) +{ + int icframe_major, icframe_minor; + int icmsg_major, icmsg_minor; + int fw_major, fw_minor; + int srv_major, srv_minor; + int i; + bool found_match = false; + + icmsghdrp->icmsgsize = 0x10; + fw_major = (fw_version >> 16); + fw_minor = (fw_version & 0xFFFF); + + srv_major = (srv_version >> 16); + srv_minor = (srv_version & 0xFFFF); + + negop = (struct icmsg_negotiate *)&buf[ + sizeof(struct vmbuspipe_hdr) + + sizeof(struct icmsg_hdr)]; + + icframe_major = negop->icframe_vercnt; + icframe_minor = 0; + + icmsg_major = negop->icmsg_vercnt; + icmsg_minor = 0; + + /* + * Select the framework version number we will + * support. + */ + + for (i = 0; i < negop->icframe_vercnt; i++) { + if ((negop->icversion_data[i].major == fw_major) && + (negop->icversion_data[i].minor == fw_minor)) { + icframe_major = negop->icversion_data[i].major; + icframe_minor = negop->icversion_data[i].minor; + found_match = true; + } + } + + if (!found_match) + goto fw_error; + + found_match = false; + + for (i = negop->icframe_vercnt; + (i < negop->icframe_vercnt + negop->icmsg_vercnt); i++) { + if ((negop->icversion_data[i].major == srv_major) && + (negop->icversion_data[i].minor == srv_minor)) { + icmsg_major = negop->icversion_data[i].major; + icmsg_minor = negop->icversion_data[i].minor; + found_match = true; + } + } + + /* + * 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; + } + + 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->inbound_lock); + spin_lock_init(&channel->sc_lock); + + INIT_LIST_HEAD(&channel->sc_list); + INIT_LIST_HEAD(&channel->percpu_list); + + channel->controlwq = create_workqueue("hv_vmbus_ctl"); + if (!channel->controlwq) { + kfree(channel); + return NULL; + } + + return channel; +} + +/* + * release_hannel - Release the vmbus channel object itself + */ +static void release_channel(struct work_struct *work) +{ + struct vmbus_channel *channel = container_of(work, + struct vmbus_channel, + work); + + destroy_workqueue(channel->controlwq); + + kfree(channel); +} + +/* + * free_channel - Release the resources used by the vmbus channel object + */ +static void free_channel(struct vmbus_channel *channel) +{ + + /* + * We have to release the channel's workqueue/thread in the vmbus's + * workqueue/thread context + * ie we can't destroy ourselves. + */ + INIT_WORK(&channel->work, release_channel); + queue_work(vmbus_connection.work_queue, &channel->work); +} + +static void percpu_channel_enq(void *arg) +{ + struct vmbus_channel *channel = arg; + int cpu = smp_processor_id(); + + list_add_tail(&channel->percpu_list, &hv_context.percpu_list[cpu]); +} + +static void percpu_channel_deq(void *arg) +{ + struct vmbus_channel *channel = arg; + + list_del(&channel->percpu_list); +} + +/* + * vmbus_process_rescind_offer - + * Rescind the offer by initiating a device removal + */ +static void vmbus_process_rescind_offer(struct work_struct *work) +{ + struct vmbus_channel *channel = container_of(work, + struct vmbus_channel, + work); + unsigned long flags; + struct vmbus_channel *primary_channel; + struct vmbus_channel_relid_released msg; + + if (channel->device_obj) + vmbus_device_unregister(channel->device_obj); + memset(&msg, 0, sizeof(struct vmbus_channel_relid_released)); + msg.child_relid = channel->offermsg.child_relid; + msg.header.msgtype = CHANNELMSG_RELID_RELEASED; + vmbus_post_msg(&msg, sizeof(struct vmbus_channel_relid_released)); + + if (channel->target_cpu != smp_processor_id()) + smp_call_function_single(channel->target_cpu, + percpu_channel_deq, channel, true); + else + percpu_channel_deq(channel); + + if (channel->primary_channel == NULL) { + spin_lock_irqsave(&vmbus_connection.channel_lock, flags); + list_del(&channel->listentry); + spin_unlock_irqrestore(&vmbus_connection.channel_lock, flags); + } else { + primary_channel = channel->primary_channel; + spin_lock_irqsave(&primary_channel->sc_lock, flags); + list_del(&channel->sc_list); + spin_unlock_irqrestore(&primary_channel->sc_lock, flags); + } + free_channel(channel); +} + +void vmbus_free_channels(void) +{ + struct vmbus_channel *channel; + + list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) { + vmbus_device_unregister(channel->device_obj); + kfree(channel->device_obj); + free_channel(channel); + } +} + +/* + * vmbus_process_offer - Process the offer by creating a channel/device + * associated with this offer + */ +static void vmbus_process_offer(struct work_struct *work) +{ + struct vmbus_channel *newchannel = container_of(work, + struct vmbus_channel, + work); + struct vmbus_channel *channel; + bool fnew = true; + bool enq = false; + int ret; + unsigned long flags; + + /* The next possible work is rescind handling */ + INIT_WORK(&newchannel->work, vmbus_process_rescind_offer); + + /* Make sure this is a new offer */ + spin_lock_irqsave(&vmbus_connection.channel_lock, flags); + + list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) { + if (!uuid_le_cmp(channel->offermsg.offer.if_type, + newchannel->offermsg.offer.if_type) && + !uuid_le_cmp(channel->offermsg.offer.if_instance, + newchannel->offermsg.offer.if_instance)) { + fnew = false; + break; + } + } + + if (fnew) { + list_add_tail(&newchannel->listentry, + &vmbus_connection.chn_list); + enq = true; + } + + spin_unlock_irqrestore(&vmbus_connection.channel_lock, flags); + + if (enq) { + if (newchannel->target_cpu != smp_processor_id()) + smp_call_function_single(newchannel->target_cpu, + percpu_channel_enq, + newchannel, true); + else + percpu_channel_enq(newchannel); + } + if (!fnew) { + /* + * Check to see if this is a sub-channel. + */ + if (newchannel->offermsg.offer.sub_channel_index != 0) { + /* + * Process the sub-channel. + */ + newchannel->primary_channel = channel; + spin_lock_irqsave(&channel->sc_lock, flags); + list_add_tail(&newchannel->sc_list, &channel->sc_list); + spin_unlock_irqrestore(&channel->sc_lock, flags); + + if (newchannel->target_cpu != smp_processor_id()) + smp_call_function_single(newchannel->target_cpu, + percpu_channel_enq, + newchannel, true); + else + percpu_channel_enq(newchannel); + + newchannel->state = CHANNEL_OPEN_STATE; + if (channel->sc_creation_callback != NULL) + channel->sc_creation_callback(newchannel); + + return; + } + + free_channel(newchannel); + return; + } + + /* + * 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; + + /* + * Start the process of binding this offer to the driver + * We need to set the DeviceObject field before calling + * vmbus_child_dev_add() + */ + newchannel->device_obj = vmbus_device_create( + &newchannel->offermsg.offer.if_type, + &newchannel->offermsg.offer.if_instance, + newchannel); + + /* + * 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); + + spin_lock_irqsave(&vmbus_connection.channel_lock, flags); + list_del(&newchannel->listentry); + spin_unlock_irqrestore(&vmbus_connection.channel_lock, flags); + kfree(newchannel->device_obj); + + free_channel(newchannel); + } +} + +enum { + IDE = 0, + SCSI, + NIC, + MAX_PERF_CHN, +}; + +/* + * This is an array of device_ids (device types) that are performance critical. + * We attempt to distribute the interrupt load for these devices across + * all available CPUs. + */ +static const struct hv_vmbus_device_id hp_devs[] = { + /* IDE */ + { HV_IDE_GUID, }, + /* Storage - SCSI */ + { HV_SCSI_GUID, }, + /* Network */ + { HV_NIC_GUID, }, +}; + + +/* + * We use this state to statically distribute the channel interrupt load. + */ +static u32 next_vp; + +/* + * Starting with Win8, we can statically distribute the incoming + * channel interrupt load by binding a channel to VCPU. We + * implement here a simple round robin scheme for distributing + * the interrupt load. + * We will bind channels that are not performance critical to cpu 0 and + * performance critical channels (IDE, SCSI and Network) will be uniformly + * distributed across all available CPUs. + */ +static void init_vp_index(struct vmbus_channel *channel, const uuid_le *type_guid) +{ + u32 cur_cpu; + int i; + bool perf_chn = false; + u32 max_cpus = num_online_cpus(); + + for (i = IDE; i < MAX_PERF_CHN; i++) { + if (!memcmp(type_guid->b, hp_devs[i].guid, + sizeof(uuid_le))) { + perf_chn = true; + break; + } + } + if ((vmbus_proto_version == VERSION_WS2008) || + (vmbus_proto_version == VERSION_WIN7) || (!perf_chn)) { + /* + * Prior to win8, all channel interrupts are + * delivered on cpu 0. + * Also if the channel is not a performance critical + * channel, bind it to cpu 0. + */ + channel->target_cpu = 0; + channel->target_vp = 0; + return; + } + cur_cpu = (++next_vp % max_cpus); + channel->target_cpu = cur_cpu; + channel->target_vp = hv_context.vp_index[cur_cpu]; +} + +/* + * 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 *newchannel; + + offer = (struct vmbus_channel_offer_channel *)hdr; + + /* Allocate the channel object and save this offer. */ + newchannel = alloc_channel(); + if (!newchannel) { + pr_err("Unable to allocate channel object\n"); + return; + } + + /* + * By default we setup state to enable batched + * reading. A specific service can choose to + * disable this prior to opening the channel. + */ + newchannel->batched_reading = true; + + /* + * Setup state for signalling the host. + */ + newchannel->sig_event = (struct hv_input_signal_event *) + (ALIGN((unsigned long) + &newchannel->sig_buf, + HV_HYPERCALL_PARAM_ALIGN)); + + newchannel->sig_event->connectionid.asu32 = 0; + newchannel->sig_event->connectionid.u.id = VMBUS_EVENT_CONNECTION_ID; + newchannel->sig_event->flag_number = 0; + newchannel->sig_event->rsvdz = 0; + + if (vmbus_proto_version != VERSION_WS2008) { + newchannel->is_dedicated_interrupt = + (offer->is_dedicated_interrupt != 0); + newchannel->sig_event->connectionid.u.id = + offer->connection_id; + } + + init_vp_index(newchannel, &offer->offer.if_type); + + memcpy(&newchannel->offermsg, offer, + sizeof(struct vmbus_channel_offer_channel)); + newchannel->monitor_grp = (u8)offer->monitorid / 32; + newchannel->monitor_bit = (u8)offer->monitorid % 32; + + INIT_WORK(&newchannel->work, vmbus_process_offer); + queue_work(newchannel->controlwq, &newchannel->work); +} + +/* + * 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; + + rescind = (struct vmbus_channel_rescind_offer *)hdr; + channel = relid2channel(rescind->child_relid); + + if (channel == NULL) + /* Just return here, no channel found */ + return; + + /* work is initialized for vmbus_process_rescind_offer() from + * vmbus_process_offer() where the channel got created */ + queue_work(channel->controlwq, &channel->work); +} + +/* + * 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; + + /* + * 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; + + /* + * 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_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; + + /* + * 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; + 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 */ +static struct vmbus_channel_message_table_entry + channel_message_table[CHANNELMSG_COUNT] = { + {CHANNELMSG_INVALID, NULL}, + {CHANNELMSG_OFFERCHANNEL, vmbus_onoffer}, + {CHANNELMSG_RESCIND_CHANNELOFFER, vmbus_onoffer_rescind}, + {CHANNELMSG_REQUESTOFFERS, NULL}, + {CHANNELMSG_ALLOFFERS_DELIVERED, vmbus_onoffers_delivered}, + {CHANNELMSG_OPENCHANNEL, NULL}, + {CHANNELMSG_OPENCHANNEL_RESULT, vmbus_onopen_result}, + {CHANNELMSG_CLOSECHANNEL, NULL}, + {CHANNELMSG_GPADL_HEADER, NULL}, + {CHANNELMSG_GPADL_BODY, NULL}, + {CHANNELMSG_GPADL_CREATED, vmbus_ongpadl_created}, + {CHANNELMSG_GPADL_TEARDOWN, NULL}, + {CHANNELMSG_GPADL_TORNDOWN, vmbus_ongpadl_torndown}, + {CHANNELMSG_RELID_RELEASED, NULL}, + {CHANNELMSG_INITIATE_CONTACT, NULL}, + {CHANNELMSG_VERSION_RESPONSE, vmbus_onversion_response}, + {CHANNELMSG_UNLOAD, NULL}, +}; + +/* + * vmbus_onmessage - Handler for channel protocol messages. + * + * This is invoked in the vmbus worker thread context. + */ +void vmbus_onmessage(void *context) +{ + struct hv_message *msg = context; + struct vmbus_channel_message_header *hdr; + int size; + + hdr = (struct vmbus_channel_message_header *)msg->u.payload; + size = msg->header.payload_size; + + if (hdr->msgtype >= CHANNELMSG_COUNT) { + pr_err("Received invalid channel message type %d size %d\n", + hdr->msgtype, size); + print_hex_dump_bytes("", DUMP_PREFIX_NONE, + (unsigned char *)msg->u.payload, size); + return; + } + + if (channel_message_table[hdr->msgtype].message_handler) + channel_message_table[hdr->msgtype].message_handler(hdr); + else + pr_err("Unhandled channel message type %d\n", hdr->msgtype); +} + +/* + * 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, t; + + msginfo = kmalloc(sizeof(*msginfo) + + sizeof(struct vmbus_channel_message_header), + GFP_KERNEL); + if (!msginfo) + return -ENOMEM; + + init_completion(&msginfo->waitevent); + + msg = (struct vmbus_channel_message_header *)msginfo->msg; + + msg->msgtype = CHANNELMSG_REQUESTOFFERS; + + + ret = vmbus_post_msg(msg, + sizeof(struct vmbus_channel_message_header)); + if (ret != 0) { + pr_err("Unable to request offers - %d\n", ret); + + goto cleanup; + } + + t = wait_for_completion_timeout(&msginfo->waitevent, 5*HZ); + if (t == 0) { + ret = -ETIMEDOUT; + goto cleanup; + } + + + +cleanup: + kfree(msginfo); + + return ret; +} + +/* + * Retrieve the (sub) channel on which to send an outgoing request. + * When a primary channel has multiple sub-channels, we choose a + * channel whose VCPU binding is closest to the VCPU on which + * this call is being made. + */ +struct vmbus_channel *vmbus_get_outgoing_channel(struct vmbus_channel *primary) +{ + struct list_head *cur, *tmp; + int cur_cpu = hv_context.vp_index[smp_processor_id()]; + struct vmbus_channel *cur_channel; + struct vmbus_channel *outgoing_channel = primary; + int cpu_distance, new_cpu_distance; + + if (list_empty(&primary->sc_list)) + return outgoing_channel; + + list_for_each_safe(cur, tmp, &primary->sc_list) { + cur_channel = list_entry(cur, struct vmbus_channel, sc_list); + if (cur_channel->state != CHANNEL_OPENED_STATE) + continue; + + if (cur_channel->target_vp == cur_cpu) + return cur_channel; + + cpu_distance = ((outgoing_channel->target_vp > cur_cpu) ? + (outgoing_channel->target_vp - cur_cpu) : + (cur_cpu - outgoing_channel->target_vp)); + + new_cpu_distance = ((cur_channel->target_vp > cur_cpu) ? + (cur_channel->target_vp - cur_cpu) : + (cur_cpu - cur_channel->target_vp)); + + if (cpu_distance < new_cpu_distance) + continue; + + outgoing_channel = cur_channel; + } + + return outgoing_channel; +} +EXPORT_SYMBOL_GPL(vmbus_get_outgoing_channel); + +static void invoke_sc_cb(struct vmbus_channel *primary_channel) +{ + struct list_head *cur, *tmp; + struct vmbus_channel *cur_channel; + + if (primary_channel->sc_creation_callback == NULL) + return; + + list_for_each_safe(cur, tmp, &primary_channel->sc_list) { + cur_channel = list_entry(cur, struct vmbus_channel, sc_list); + + primary_channel->sc_creation_callback(cur_channel); + } +} + +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); + +bool vmbus_are_subchannels_present(struct vmbus_channel *primary) +{ + bool ret; + + ret = !list_empty(&primary->sc_list); + + if (ret) { + /* + * Invoke the callback on sub-channel creation. + * This will present a uniform interface to the + * clients. + */ + invoke_sc_cb(primary); + } + + return ret; +} +EXPORT_SYMBOL_GPL(vmbus_are_subchannels_present); |