/* * 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 * Hank Janssen */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include #include #include #include #include #include #include #include "hyperv_vmbus.h" #define NUM_PAGES_SPANNED(addr, len) \ ((PAGE_ALIGN(addr + len) >> PAGE_SHIFT) - (addr >> PAGE_SHIFT)) /* * vmbus_setevent- Trigger an event notification on the specified * channel. */ static void vmbus_setevent(struct vmbus_channel *channel) { struct hv_monitor_page *monitorpage; if (channel->offermsg.monitor_allocated) { /* Each u32 represents 32 channels */ sync_set_bit(channel->offermsg.child_relid & 31, (unsigned long *) vmbus_connection.send_int_page + (channel->offermsg.child_relid >> 5)); monitorpage = vmbus_connection.monitor_pages; monitorpage++; /* Get the child to parent monitor page */ sync_set_bit(channel->monitor_bit, (unsigned long *)&monitorpage->trigger_group [channel->monitor_grp].pending); } else { vmbus_set_event(channel); } } /* * vmbus_get_debug_info -Retrieve various channel debug info */ void vmbus_get_debug_info(struct vmbus_channel *channel, struct vmbus_channel_debug_info *debuginfo) { struct hv_monitor_page *monitorpage; u8 monitor_group = (u8)channel->offermsg.monitorid / 32; u8 monitor_offset = (u8)channel->offermsg.monitorid % 32; debuginfo->relid = channel->offermsg.child_relid; debuginfo->state = channel->state; memcpy(&debuginfo->interfacetype, &channel->offermsg.offer.if_type, sizeof(uuid_le)); memcpy(&debuginfo->interface_instance, &channel->offermsg.offer.if_instance, sizeof(uuid_le)); monitorpage = (struct hv_monitor_page *)vmbus_connection.monitor_pages; debuginfo->monitorid = channel->offermsg.monitorid; debuginfo->servermonitor_pending = monitorpage->trigger_group[monitor_group].pending; debuginfo->servermonitor_latency = monitorpage->latency[monitor_group][monitor_offset]; debuginfo->servermonitor_connectionid = monitorpage->parameter[monitor_group] [monitor_offset].connectionid.u.id; monitorpage++; debuginfo->clientmonitor_pending = monitorpage->trigger_group[monitor_group].pending; debuginfo->clientmonitor_latency = monitorpage->latency[monitor_group][monitor_offset]; debuginfo->clientmonitor_connectionid = monitorpage->parameter[monitor_group] [monitor_offset].connectionid.u.id; hv_ringbuffer_get_debuginfo(&channel->inbound, &debuginfo->inbound); hv_ringbuffer_get_debuginfo(&channel->outbound, &debuginfo->outbound); } /* * vmbus_open - Open the specified channel. */ int vmbus_open(struct vmbus_channel *newchannel, u32 send_ringbuffer_size, u32 recv_ringbuffer_size, void *userdata, u32 userdatalen, void (*onchannelcallback)(void *context), void *context) { struct vmbus_channel_open_channel *open_msg; struct vmbus_channel_msginfo *open_info = NULL; void *in, *out; unsigned long flags; int ret, t, err = 0; newchannel->onchannel_callback = onchannelcallback; newchannel->channel_callback_context = context; /* Allocate the ring buffer */ out = (void *)__get_free_pages(GFP_KERNEL|__GFP_ZERO, get_order(send_ringbuffer_size + recv_ringbuffer_size)); if (!out) return -ENOMEM; in = (void *)((unsigned long)out + send_ringbuffer_size); newchannel->ringbuffer_pages = out; newchannel->ringbuffer_pagecount = (send_ringbuffer_size + recv_ringbuffer_size) >> PAGE_SHIFT; ret = hv_ringbuffer_init( &newchannel->outbound, out, send_ringbuffer_size); if (ret != 0) { err = ret; goto error0; } ret = hv_ringbuffer_init( &newchannel->inbound, in, recv_ringbuffer_size); if (ret != 0) { err = ret; goto error0; } /* Establish the gpadl for the ring buffer */ newchannel->ringbuffer_gpadlhandle = 0; ret = vmbus_establish_gpadl(newchannel, newchannel->outbound.ring_buffer, send_ringbuffer_size + recv_ringbuffer_size, &newchannel->ringbuffer_gpadlhandle); if (ret != 0) { err = ret; goto error0; } /* Create and init the channel open message */ open_info = kmalloc(sizeof(*open_info) + sizeof(struct vmbus_channel_open_channel), GFP_KERNEL); if (!open_info) { err = -ENOMEM; goto error0; } init_completion(&open_info->waitevent); open_msg = (struct vmbus_channel_open_channel *)open_info->msg; open_msg->header.msgtype = CHANNELMSG_OPENCHANNEL; open_msg->openid = newchannel->offermsg.child_relid; open_msg->child_relid = newchannel->offermsg.child_relid; open_msg->ringbuffer_gpadlhandle = newchannel->ringbuffer_gpadlhandle; open_msg->downstream_ringbuffer_pageoffset = send_ringbuffer_size >> PAGE_SHIFT; open_msg->target_vp = newchannel->target_vp; if (userdatalen > MAX_USER_DEFINED_BYTES) { err = -EINVAL; goto error0; } if (userdatalen) memcpy(open_msg->userdata, userdata, userdatalen); spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags); list_add_tail(&open_info->msglistentry, &vmbus_connection.chn_msg_list); spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags); ret = vmbus_post_msg(open_msg, sizeof(struct vmbus_channel_open_channel)); if (ret != 0) { err = ret; goto error1; } t = wait_for_completion_timeout(&open_info->waitevent, 5*HZ); if (t == 0) { err = -ETIMEDOUT; goto error1; } if (open_info->response.open_result.status) err = open_info->response.open_result.status; spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags); list_del(&open_info->msglistentry); spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags); kfree(open_info); return err; error1: spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags); list_del(&open_info->msglistentry); spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags); error0: free_pages((unsigned long)out, get_order(send_ringbuffer_size + recv_ringbuffer_size)); kfree(open_info); return err; } EXPORT_SYMBOL_GPL(vmbus_open); /* * create_gpadl_header - Creates a gpadl for the specified buffer */ static int create_gpadl_header(void *kbuffer, u32 size, struct vmbus_channel_msginfo **msginfo, u32 *messagecount) { int i; int pagecount; unsigned long long pfn; struct vmbus_channel_gpadl_header *gpadl_header; struct vmbus_channel_gpadl_body *gpadl_body; struct vmbus_channel_msginfo *msgheader; struct vmbus_channel_msginfo *msgbody = NULL; u32 msgsize; int pfnsum, pfncount, pfnleft, pfncurr, pfnsize; pagecount = size >> PAGE_SHIFT; pfn = virt_to_phys(kbuffer) >> PAGE_SHIFT; /* do we need a gpadl body msg */ pfnsize = MAX_SIZE_CHANNEL_MESSAGE - sizeof(struct vmbus_channel_gpadl_header) - sizeof(struct gpa_range); pfncount = pfnsize / sizeof(u64); if (pagecount > pfncount) { /* we need a gpadl body */ /* fill in the header */ msgsize = sizeof(struct vmbus_channel_msginfo) + sizeof(struct vmbus_channel_gpadl_header) + sizeof(struct gpa_range) + pfncount * sizeof(u64); msgheader = kzalloc(msgsize, GFP_KERNEL); if (!msgheader) goto nomem; INIT_LIST_HEAD(&msgheader->submsglist); msgheader->msgsize = msgsize; gpadl_header = (struct vmbus_channel_gpadl_header *) msgheader->msg; gpadl_header->rangecount = 1; gpadl_header->range_buflen = sizeof(struct gpa_range) + pagecount * sizeof(u64); gpadl_header->range[0].byte_offset = 0; gpadl_header->range[0].byte_count = size; for (i = 0; i < pfncount; i++) gpadl_header->range[0].pfn_array[i] = pfn+i; *msginfo = msgheader; *messagecount = 1; pfnsum = pfncount; pfnleft = pagecount - pfncount; /* how many pfns can we fit */ pfnsize = MAX_SIZE_CHANNEL_MESSAGE - sizeof(struct vmbus_channel_gpadl_body); pfncount = pfnsize / sizeof(u64); /* fill in the body */ while (pfnleft) { if (pfnleft > pfncount) pfncurr = pfncount; else pfncurr = pfnleft; msgsize = sizeof(struct vmbus_channel_msginfo) + sizeof(struct vmbus_channel_gpadl_body) + pfncurr * sizeof(u64); msgbody = kzalloc(msgsize, GFP_KERNEL); if (!msgbody) { struct vmbus_channel_msginfo *pos = NULL; struct vmbus_channel_msginfo *tmp = NULL; /* * Free up all the allocated messages. */ list_for_each_entry_safe(pos, tmp, &msgheader->submsglist, msglistentry) { list_del(&pos->msglistentry); kfree(pos); } goto nomem; } msgbody->msgsize = msgsize; (*messagecount)++; gpadl_body = (struct vmbus_channel_gpadl_body *)msgbody->msg; /* * Gpadl is u32 and we are using a pointer which could * be 64-bit * This is governed by the guest/host protocol and * so the hypervisor gurantees that this is ok. */ for (i = 0; i < pfncurr; i++) gpadl_body->pfn[i] = pfn + pfnsum + i; /* add to msg header */ list_add_tail(&msgbody->msglistentry, &msgheader->submsglist); pfnsum += pfncurr; pfnleft -= pfncurr; } } else { /* everything fits in a header */ msgsize = sizeof(struct vmbus_channel_msginfo) + sizeof(struct vmbus_channel_gpadl_header) + sizeof(struct gpa_range) + pagecount * sizeof(u64); msgheader = kzalloc(msgsize, GFP_KERNEL); if (msgheader == NULL) goto nomem; msgheader->msgsize = msgsize; gpadl_header = (struct vmbus_channel_gpadl_header *) msgheader->msg; gpadl_header->rangecount = 1; gpadl_header->range_buflen = sizeof(struct gpa_range) + pagecount * sizeof(u64); gpadl_header->range[0].byte_offset = 0; gpadl_header->range[0].byte_count = size; for (i = 0; i < pagecount; i++) gpadl_header->range[0].pfn_array[i] = pfn+i; *msginfo = msgheader; *messagecount = 1; } return 0; nomem: kfree(msgheader); kfree(msgbody); return -ENOMEM; } /* * vmbus_establish_gpadl - Estabish a GPADL for the specified buffer * * @channel: a channel * @kbuffer: from kmalloc * @size: page-size multiple * @gpadl_handle: some funky thing */ int vmbus_establish_gpadl(struct vmbus_channel *channel, void *kbuffer, u32 size, u32 *gpadl_handle) { struct vmbus_channel_gpadl_header *gpadlmsg; struct vmbus_channel_gpadl_body *gpadl_body; struct vmbus_channel_msginfo *msginfo = NULL; struct vmbus_channel_msginfo *submsginfo; u32 msgcount; struct list_head *curr; u32 next_gpadl_handle; unsigned long flags; int ret = 0; next_gpadl_handle = atomic_read(&vmbus_connection.next_gpadl_handle); atomic_inc(&vmbus_connection.next_gpadl_handle); ret = create_gpadl_header(kbuffer, size, &msginfo, &msgcount); if (ret) return ret; init_completion(&msginfo->waitevent); gpadlmsg = (struct vmbus_channel_gpadl_header *)msginfo->msg; gpadlmsg->header.msgtype = CHANNELMSG_GPADL_HEADER; gpadlmsg->child_relid = channel->offermsg.child_relid; gpadlmsg->gpadl = next_gpadl_handle; spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags); list_add_tail(&msginfo->msglistentry, &vmbus_connection.chn_msg_list); spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags); ret = vmbus_post_msg(gpadlmsg, msginfo->msgsize - sizeof(*msginfo)); if (ret != 0) goto cleanup; if (msgcount > 1) { list_for_each(curr, &msginfo->submsglist) { submsginfo = (struct vmbus_channel_msginfo *)curr; gpadl_body = (struct vmbus_channel_gpadl_body *)submsginfo->msg; gpadl_body->header.msgtype = CHANNELMSG_GPADL_BODY; gpadl_body->gpadl = next_gpadl_handle; ret = vmbus_post_msg(gpadl_body, submsginfo->msgsize - sizeof(*submsginfo)); if (ret != 0) goto cleanup; } } wait_for_completion(&msginfo->waitevent); /* At this point, we received the gpadl created msg */ *gpadl_handle = gpadlmsg->gpadl; cleanup: spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags); list_del(&msginfo->msglistentry); spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags); kfree(msginfo); return ret; } EXPORT_SYMBOL_GPL(vmbus_establish_gpadl); /* * vmbus_teardown_gpadl -Teardown the specified GPADL handle */ int vmbus_teardown_gpadl(struct vmbus_channel *channel, u32 gpadl_handle) { struct vmbus_channel_gpadl_teardown *msg; struct vmbus_channel_msginfo *info; unsigned long flags; int ret; info = kmalloc(sizeof(*info) + sizeof(struct vmbus_channel_gpadl_teardown), GFP_KERNEL); if (!info) return -ENOMEM; init_completion(&info->waitevent); msg = (struct vmbus_channel_gpadl_teardown *)info->msg; msg->header.msgtype = CHANNELMSG_GPADL_TEARDOWN; msg->child_relid = channel->offermsg.child_relid; msg->gpadl = gpadl_handle; spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags); list_add_tail(&info->msglistentry, &vmbus_connection.chn_msg_list); spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags); ret = vmbus_post_msg(msg, sizeof(struct vmbus_channel_gpadl_teardown)); if (ret) goto post_msg_err; wait_for_completion(&info->waitevent); post_msg_err: spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags); list_del(&info->msglistentry); spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags); kfree(info); return ret; } EXPORT_SYMBOL_GPL(vmbus_teardown_gpadl); /* * vmbus_close - Close the specified channel */ void vmbus_close(struct vmbus_channel *channel) { struct vmbus_channel_close_channel *msg; int ret; unsigned long flags; /* Stop callback and cancel the timer asap */ spin_lock_irqsave(&channel->inbound_lock, flags); channel->onchannel_callback = NULL; spin_unlock_irqrestore(&channel->inbound_lock, flags); /* Send a closing message */ msg = &channel->close_msg.msg; msg->header.msgtype = CHANNELMSG_CLOSECHANNEL; msg->child_relid = channel->offermsg.child_relid; ret = vmbus_post_msg(msg, sizeof(struct vmbus_channel_close_channel)); BUG_ON(ret != 0); /* Tear down the gpadl for the channel's ring buffer */ if (channel->ringbuffer_gpadlhandle) vmbus_teardown_gpadl(channel, channel->ringbuffer_gpadlhandle); /* Cleanup the ring buffers for this channel */ hv_ringbuffer_cleanup(&channel->outbound); hv_ringbuffer_cleanup(&channel->inbound); free_pages((unsigned long)channel->ringbuffer_pages, get_order(channel->ringbuffer_pagecount * PAGE_SIZE)); } EXPORT_SYMBOL_GPL(vmbus_close); /** * vmbus_sendpacket() - Send the specified buffer on the given channel * @channel: Pointer to vmbus_channel structure. * @buffer: Pointer to the buffer you want to receive the data into. * @bufferlen: Maximum size of what the the buffer will hold * @requestid: Identifier of the request * @type: Type of packet that is being send e.g. negotiate, time * packet etc. * * Sends data in @buffer directly to hyper-v via the vmbus * This will send the data unparsed to hyper-v. * * Mainly used by Hyper-V drivers. */ int vmbus_sendpacket(struct vmbus_channel *channel, const void *buffer, u32 bufferlen, u64 requestid, enum vmbus_packet_type type, u32 flags) { struct vmpacket_descriptor desc; u32 packetlen = sizeof(struct vmpacket_descriptor) + bufferlen; u32 packetlen_aligned = ALIGN(packetlen, sizeof(u64)); struct scatterlist bufferlist[3]; u64 aligned_data = 0; int ret; bool signal = false; /* Setup the descriptor */ desc.type = type; /* VmbusPacketTypeDataInBand; */ desc.flags = flags; /* VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED; */ /* in 8-bytes granularity */ desc.offset8 = sizeof(struct vmpacket_descriptor) >> 3; desc.len8 = (u16)(packetlen_aligned >> 3); desc.trans_id = requestid; sg_init_table(bufferlist, 3); sg_set_buf(&bufferlist[0], &desc, sizeof(struct vmpacket_descriptor)); sg_set_buf(&bufferlist[1], buffer, bufferlen); sg_set_buf(&bufferlist[2], &aligned_data, packetlen_aligned - packetlen); ret = hv_ringbuffer_write(&channel->outbound, bufferlist, 3, &signal); if (ret == 0 && signal) vmbus_setevent(channel); return ret; } EXPORT_SYMBOL(vmbus_sendpacket); /* * vmbus_sendpacket_pagebuffer - Send a range of single-page buffer * packets using a GPADL Direct packet type. */ int vmbus_sendpacket_pagebuffer(struct vmbus_channel *channel, struct hv_page_buffer pagebuffers[], u32 pagecount, void *buffer, u32 bufferlen, u64 requestid) { int ret; int i; struct vmbus_channel_packet_page_buffer desc; u32 descsize; u32 packetlen; u32 packetlen_aligned; struct scatterlist bufferlist[3]; u64 aligned_data = 0; bool signal = false; if (pagecount > MAX_PAGE_BUFFER_COUNT) return -EINVAL; /* * Adjust the size down since vmbus_channel_packet_page_buffer is the * largest size we support */ descsize = sizeof(struct vmbus_channel_packet_page_buffer) - ((MAX_PAGE_BUFFER_COUNT - pagecount) * sizeof(struct hv_page_buffer)); packetlen = descsize + bufferlen; packetlen_aligned = ALIGN(packetlen, sizeof(u64)); /* Setup the descriptor */ desc.type = VM_PKT_DATA_USING_GPA_DIRECT; desc.flags = VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED; desc.dataoffset8 = descsize >> 3; /* in 8-bytes grandularity */ desc.length8 = (u16)(packetlen_aligned >> 3); desc.transactionid = requestid; desc.rangecount = pagecount; for (i = 0; i < pagecount; i++) { desc.range[i].len = pagebuffers[i].len; desc.range[i].offset = pagebuffers[i].offset; desc.range[i].pfn = pagebuffers[i].pfn; } sg_init_table(bufferlist, 3); sg_set_buf(&bufferlist[0], &desc, descsize); sg_set_buf(&bufferlist[1], buffer, bufferlen); sg_set_buf(&bufferlist[2], &aligned_data, packetlen_aligned - packetlen); ret = hv_ringbuffer_write(&channel->outbound, bufferlist, 3, &signal); if (ret == 0 && signal) vmbus_setevent(channel); return ret; } EXPORT_SYMBOL_GPL(vmbus_sendpacket_pagebuffer); /* * vmbus_sendpacket_multipagebuffer - Send a multi-page buffer packet * using a GPADL Direct packet type. */ int vmbus_sendpacket_multipagebuffer(struct vmbus_channel *channel, struct hv_multipage_buffer *multi_pagebuffer, void *buffer, u32 bufferlen, u64 requestid) { int ret; struct vmbus_channel_packet_multipage_buffer desc; u32 descsize; u32 packetlen; u32 packetlen_aligned; struct scatterlist bufferlist[3]; u64 aligned_data = 0; bool signal = false; u32 pfncount = NUM_PAGES_SPANNED(multi_pagebuffer->offset, multi_pagebuffer->len); if ((pfncount < 0) || (pfncount > MAX_MULTIPAGE_BUFFER_COUNT)) return -EINVAL; /* * Adjust the size down since vmbus_channel_packet_multipage_buffer is * the largest size we support */ descsize = sizeof(struct vmbus_channel_packet_multipage_buffer) - ((MAX_MULTIPAGE_BUFFER_COUNT - pfncount) * sizeof(u64)); packetlen = descsize + bufferlen; packetlen_aligned = ALIGN(packetlen, sizeof(u64)); /* Setup the descriptor */ desc.type = VM_PKT_DATA_USING_GPA_DIRECT; desc.flags = VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED; desc.dataoffset8 = descsize >> 3; /* in 8-bytes grandularity */ desc.length8 = (u16)(packetlen_aligned >> 3); desc.transactionid = requestid; desc.rangecount = 1; desc.range.len = multi_pagebuffer->len; desc.range.offset = multi_pagebuffer->offset; memcpy(desc.range.pfn_array, multi_pagebuffer->pfn_array, pfncount * sizeof(u64)); sg_init_table(bufferlist, 3); sg_set_buf(&bufferlist[0], &desc, descsize); sg_set_buf(&bufferlist[1], buffer, bufferlen); sg_set_buf(&bufferlist[2], &aligned_data, packetlen_aligned - packetlen); ret = hv_ringbuffer_write(&channel->outbound, bufferlist, 3, &signal); if (ret == 0 && signal) vmbus_setevent(channel); return ret; } EXPORT_SYMBOL_GPL(vmbus_sendpacket_multipagebuffer); /** * vmbus_recvpacket() - Retrieve the user packet on the specified channel * @channel: Pointer to vmbus_channel structure. * @buffer: Pointer to the buffer you want to receive the data into. * @bufferlen: Maximum size of what the the buffer will hold * @buffer_actual_len: The actual size of the data after it was received * @requestid: Identifier of the request * * Receives directly from the hyper-v vmbus and puts the data it received * into Buffer. This will receive the data unparsed from hyper-v. * * Mainly used by Hyper-V drivers. */ int vmbus_recvpacket(struct vmbus_channel *channel, void *buffer, u32 bufferlen, u32 *buffer_actual_len, u64 *requestid) { struct vmpacket_descriptor desc; u32 packetlen; u32 userlen; int ret; bool signal = false; *buffer_actual_len = 0; *requestid = 0; ret = hv_ringbuffer_peek(&channel->inbound, &desc, sizeof(struct vmpacket_descriptor)); if (ret != 0) return 0; packetlen = desc.len8 << 3; userlen = packetlen - (desc.offset8 << 3); *buffer_actual_len = userlen; if (userlen > bufferlen) { pr_err("Buffer too small - got %d needs %d\n", bufferlen, userlen); return -ETOOSMALL; } *requestid = desc.trans_id; /* Copy over the packet to the user buffer */ ret = hv_ringbuffer_read(&channel->inbound, buffer, userlen, (desc.offset8 << 3), &signal); if (signal) vmbus_setevent(channel); return 0; } EXPORT_SYMBOL(vmbus_recvpacket); /* * vmbus_recvpacket_raw - Retrieve the raw packet on the specified channel */ int vmbus_recvpacket_raw(struct vmbus_channel *channel, void *buffer, u32 bufferlen, u32 *buffer_actual_len, u64 *requestid) { struct vmpacket_descriptor desc; u32 packetlen; int ret; bool signal = false; *buffer_actual_len = 0; *requestid = 0; ret = hv_ringbuffer_peek(&channel->inbound, &desc, sizeof(struct vmpacket_descriptor)); if (ret != 0) return 0; packetlen = desc.len8 << 3; *buffer_actual_len = packetlen; if (packetlen > bufferlen) { pr_err("Buffer too small - needed %d bytes but " "got space for only %d bytes\n", packetlen, bufferlen); return -ENOBUFS; } *requestid = desc.trans_id; /* Copy over the entire packet to the user buffer */ ret = hv_ringbuffer_read(&channel->inbound, buffer, packetlen, 0, &signal); if (signal) vmbus_setevent(channel); return 0; } EXPORT_SYMBOL_GPL(vmbus_recvpacket_raw);