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OpenCloudOS-Kernel/drivers/hv/channel.c

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/*
* 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/module.h>
#include <linux/hyperv.h>
#include <linux/uio.h>
#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));
/* Get the child to parent monitor page */
monitorpage = vmbus_connection.monitor_pages[1];
sync_set_bit(channel->monitor_bit,
(unsigned long *)&monitorpage->trigger_group
[channel->monitor_grp].pending);
} else {
vmbus_set_event(channel);
}
}
/*
* 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;
spin_lock_irqsave(&newchannel->sc_lock, flags);
if (newchannel->state == CHANNEL_OPEN_STATE) {
newchannel->state = CHANNEL_OPENING_STATE;
} else {
spin_unlock_irqrestore(&newchannel->sc_lock, flags);
return -EINVAL;
}
spin_unlock_irqrestore(&newchannel->sc_lock, flags);
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)
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);
if (err == 0)
newchannel->state = CHANNEL_OPENED_STATE;
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;
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;
/* 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] = slow_virt_to_phys(
kbuffer + PAGE_SIZE * i) >> PAGE_SHIFT;
*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] = slow_virt_to_phys(
kbuffer + PAGE_SIZE * (pfnsum + i)) >>
PAGE_SHIFT;
/* 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] = slow_virt_to_phys(
kbuffer + PAGE_SIZE * i) >> PAGE_SHIFT;
*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 or vmalloc
* @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;
int t;
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;
}
}
t = wait_for_completion_timeout(&msginfo->waitevent, 5*HZ);
BUG_ON(t == 0);
/* 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, t;
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));
BUG_ON(ret != 0);
t = wait_for_completion_timeout(&info->waitevent, 5*HZ);
BUG_ON(t == 0);
/* Received a torndown response */
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);
static void reset_channel_cb(void *arg)
{
struct vmbus_channel *channel = arg;
channel->onchannel_callback = NULL;
}
static void vmbus_close_internal(struct vmbus_channel *channel)
{
struct vmbus_channel_close_channel *msg;
int ret;
channel->state = CHANNEL_OPEN_STATE;
channel->sc_creation_callback = NULL;
/* Stop callback and cancel the timer asap */
if (channel->target_cpu != smp_processor_id())
smp_call_function_single(channel->target_cpu, reset_channel_cb,
channel, true);
else
reset_channel_cb(channel);
/* 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));
}
/*
* vmbus_close - Close the specified channel
*/
void vmbus_close(struct vmbus_channel *channel)
{
struct list_head *cur, *tmp;
struct vmbus_channel *cur_channel;
if (channel->primary_channel != NULL) {
/*
* We will only close sub-channels when
* the primary is closed.
*/
return;
}
/*
* Close all the sub-channels first and then close the
* primary channel.
*/
list_for_each_safe(cur, tmp, &channel->sc_list) {
cur_channel = list_entry(cur, struct vmbus_channel, sc_list);
if (cur_channel->state != CHANNEL_OPENED_STATE)
continue;
vmbus_close_internal(cur_channel);
}
/*
* Now close the primary.
*/
vmbus_close_internal(channel);
}
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, 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 kvec 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;
bufferlist[0].iov_base = &desc;
bufferlist[0].iov_len = sizeof(struct vmpacket_descriptor);
bufferlist[1].iov_base = buffer;
bufferlist[1].iov_len = bufferlen;
bufferlist[2].iov_base = &aligned_data;
bufferlist[2].iov_len = (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 kvec 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;
}
bufferlist[0].iov_base = &desc;
bufferlist[0].iov_len = descsize;
bufferlist[1].iov_base = buffer;
bufferlist[1].iov_len = bufferlen;
bufferlist[2].iov_base = &aligned_data;
bufferlist[2].iov_len = (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 kvec bufferlist[3];
u64 aligned_data = 0;
bool signal = false;
u32 pfncount = NUM_PAGES_SPANNED(multi_pagebuffer->offset,
multi_pagebuffer->len);
if (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));
bufferlist[0].iov_base = &desc;
bufferlist[0].iov_len = descsize;
bufferlist[1].iov_base = buffer;
bufferlist[1].iov_len = bufferlen;
bufferlist[2].iov_base = &aligned_data;
bufferlist[2].iov_len = (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 ret;
}
EXPORT_SYMBOL_GPL(vmbus_recvpacket_raw);
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