[deliverable/linux.git] / drivers / hv / hv_snapshot.c

/*
 * An implementation of host initiated guest snapshot.
 *
 *
 * Copyright (C) 2013, Microsoft, Inc.
 * Author : K. Y. Srinivasan <kys@microsoft.com>
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 as published
 * by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
 * NON INFRINGEMENT.  See the GNU General Public License for more
 * details.
 *
 */
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/net.h>
#include <linux/nls.h>
#include <linux/connector.h>
#include <linux/workqueue.h>
#include <linux/hyperv.h>

#include "hyperv_vmbus.h"
#include "hv_utils_transport.h"

#define VSS_MAJOR  5
#define VSS_MINOR  0
#define VSS_VERSION    (VSS_MAJOR << 16 | VSS_MINOR)

#define VSS_USERSPACE_TIMEOUT (msecs_to_jiffies(10 * 1000))

/*
 * Global state maintained for transaction that is being processed. For a class
 * of integration services, including the "VSS service", the specified protocol
 * is a "request/response" protocol which means that there can only be single
 * outstanding transaction from the host at any given point in time. We use
 * this to simplify memory management in this driver - we cache and process
 * only one message at a time.
 *
 * While the request/response protocol is guaranteed by the host, we further
 * ensure this by serializing packet processing in this driver - we do not
 * read additional packets from the VMBUs until the current packet is fully
 * handled.
 */

static struct {
	int state;   /* hvutil_device_state */
	int recv_len; /* number of bytes received. */
	struct vmbus_channel *recv_channel; /* chn we got the request */
	u64 recv_req_id; /* request ID. */
	struct hv_vss_msg  *msg; /* current message */
} vss_transaction;


static void vss_respond_to_host(int error);

/*
 * This state maintains the version number registered by the daemon.
 */
static int dm_reg_value;

static const char vss_devname[] = "vmbus/hv_vss";
static __u8 *recv_buffer;
static struct hvutil_transport *hvt;

static void vss_timeout_func(struct work_struct *dummy);
static void vss_handle_request(struct work_struct *dummy);

static DECLARE_DELAYED_WORK(vss_timeout_work, vss_timeout_func);
static DECLARE_WORK(vss_handle_request_work, vss_handle_request);

static void vss_poll_wrapper(void *channel)
{
	/* Transaction is finished, reset the state here to avoid races. */
	vss_transaction.state = HVUTIL_READY;
	hv_vss_onchannelcallback(channel);
}

/*
 * Callback when data is received from user mode.
 */

static void vss_timeout_func(struct work_struct *dummy)
{
	/*
	 * Timeout waiting for userspace component to reply happened.
	 */
	pr_warn("VSS: timeout waiting for daemon to reply\n");
	vss_respond_to_host(HV_E_FAIL);

	hv_poll_channel(vss_transaction.recv_channel, vss_poll_wrapper);
}

static void vss_register_done(void)
{
	hv_poll_channel(vss_transaction.recv_channel, vss_poll_wrapper);
	pr_debug("VSS: userspace daemon registered\n");
}

static int vss_handle_handshake(struct hv_vss_msg *vss_msg)
{
	u32 our_ver = VSS_OP_REGISTER1;

	switch (vss_msg->vss_hdr.operation) {
	case VSS_OP_REGISTER:
		/* Daemon doesn't expect us to reply */
		dm_reg_value = VSS_OP_REGISTER;
		break;
	case VSS_OP_REGISTER1:
		/* Daemon expects us to reply with our own version */
		if (hvutil_transport_send(hvt, &our_ver, sizeof(our_ver),
					  vss_register_done))
			return -EFAULT;
		dm_reg_value = VSS_OP_REGISTER1;
		break;
	default:
		return -EINVAL;
	}
	pr_debug("VSS: userspace daemon ver. %d connected\n", dm_reg_value);
	return 0;
}

static int vss_on_msg(void *msg, int len)
{
	struct hv_vss_msg *vss_msg = (struct hv_vss_msg *)msg;

	if (len != sizeof(*vss_msg))
		return -EINVAL;

	if (vss_msg->vss_hdr.operation == VSS_OP_REGISTER ||
	    vss_msg->vss_hdr.operation == VSS_OP_REGISTER1) {
		/*
		 * Don't process registration messages if we're in the middle
		 * of a transaction processing.
		 */
		if (vss_transaction.state > HVUTIL_READY)
			return -EINVAL;
		return vss_handle_handshake(vss_msg);
	} else if (vss_transaction.state == HVUTIL_USERSPACE_REQ) {
		vss_transaction.state = HVUTIL_USERSPACE_RECV;

		if (vss_msg->vss_hdr.operation == VSS_OP_HOT_BACKUP)
			vss_transaction.msg->vss_cf.flags =
				VSS_HBU_NO_AUTO_RECOVERY;

		if (cancel_delayed_work_sync(&vss_timeout_work)) {
			vss_respond_to_host(vss_msg->error);
			/* Transaction is finished, reset the state. */
			hv_poll_channel(vss_transaction.recv_channel,
					vss_poll_wrapper);
		}
	} else {
		/* This is a spurious call! */
		pr_warn("VSS: Transaction not active\n");
		return -EINVAL;
	}
	return 0;
}

static void vss_send_op(void)
{
	int op = vss_transaction.msg->vss_hdr.operation;
	int rc;
	struct hv_vss_msg *vss_msg;

	/* The transaction state is wrong. */
	if (vss_transaction.state != HVUTIL_HOSTMSG_RECEIVED)
		return;

	vss_msg = kzalloc(sizeof(*vss_msg), GFP_KERNEL);
	if (!vss_msg)
		return;

	vss_msg->vss_hdr.operation = op;

	vss_transaction.state = HVUTIL_USERSPACE_REQ;

	schedule_delayed_work(&vss_timeout_work, VSS_USERSPACE_TIMEOUT);

	rc = hvutil_transport_send(hvt, vss_msg, sizeof(*vss_msg), NULL);
	if (rc) {
		pr_warn("VSS: failed to communicate to the daemon: %d\n", rc);
		if (cancel_delayed_work_sync(&vss_timeout_work)) {
			vss_respond_to_host(HV_E_FAIL);
			vss_transaction.state = HVUTIL_READY;
		}
	}

	kfree(vss_msg);

	return;
}

static void vss_handle_request(struct work_struct *dummy)
{
	switch (vss_transaction.msg->vss_hdr.operation) {
	/*
	 * Initiate a "freeze/thaw" operation in the guest.
	 * We respond to the host once the operation is complete.
	 *
	 * We send the message to the user space daemon and the operation is
	 * performed in the daemon.
	 */
	case VSS_OP_THAW:
	case VSS_OP_FREEZE:
	case VSS_OP_HOT_BACKUP:
		if (vss_transaction.state < HVUTIL_READY) {
			/* Userspace is not registered yet */
			vss_respond_to_host(HV_E_FAIL);
			return;
		}
		vss_transaction.state = HVUTIL_HOSTMSG_RECEIVED;
		vss_send_op();
		return;
	case VSS_OP_GET_DM_INFO:
		vss_transaction.msg->dm_info.flags = 0;
		break;
	default:
		break;
	}

	vss_respond_to_host(0);
	hv_poll_channel(vss_transaction.recv_channel, vss_poll_wrapper);
}

/*
 * Send a response back to the host.
 */

static void
vss_respond_to_host(int error)
{
	struct icmsg_hdr *icmsghdrp;
	u32	buf_len;
	struct vmbus_channel *channel;
	u64	req_id;

	/*
	 * Copy the global state for completing the transaction. Note that
	 * only one transaction can be active at a time.
	 */

	buf_len = vss_transaction.recv_len;
	channel = vss_transaction.recv_channel;
	req_id = vss_transaction.recv_req_id;

	icmsghdrp = (struct icmsg_hdr *)
			&recv_buffer[sizeof(struct vmbuspipe_hdr)];

	if (channel->onchannel_callback == NULL)
		/*
		 * We have raced with util driver being unloaded;
		 * silently return.
		 */
		return;

	icmsghdrp->status = error;

	icmsghdrp->icflags = ICMSGHDRFLAG_TRANSACTION | ICMSGHDRFLAG_RESPONSE;

	vmbus_sendpacket(channel, recv_buffer, buf_len, req_id,
				VM_PKT_DATA_INBAND, 0);

}

/*
 * This callback is invoked when we get a VSS message from the host.
 * The host ensures that only one VSS transaction can be active at a time.
 */

void hv_vss_onchannelcallback(void *context)
{
	struct vmbus_channel *channel = context;
	u32 recvlen;
	u64 requestid;
	struct hv_vss_msg *vss_msg;


	struct icmsg_hdr *icmsghdrp;
	struct icmsg_negotiate *negop = NULL;

	if (vss_transaction.state > HVUTIL_READY)
		return;

	vmbus_recvpacket(channel, recv_buffer, PAGE_SIZE * 2, &recvlen,
			 &requestid);

	if (recvlen > 0) {
		icmsghdrp = (struct icmsg_hdr *)&recv_buffer[
			sizeof(struct vmbuspipe_hdr)];

		if (icmsghdrp->icmsgtype == ICMSGTYPE_NEGOTIATE) {
			vmbus_prep_negotiate_resp(icmsghdrp, negop,
				 recv_buffer, UTIL_FW_VERSION,
				 VSS_VERSION);
		} else {
			vss_msg = (struct hv_vss_msg *)&recv_buffer[
				sizeof(struct vmbuspipe_hdr) +
				sizeof(struct icmsg_hdr)];

			/*
			 * Stash away this global state for completing the
			 * transaction; note transactions are serialized.
			 */

			vss_transaction.recv_len = recvlen;
			vss_transaction.recv_req_id = requestid;
			vss_transaction.msg = (struct hv_vss_msg *)vss_msg;

			schedule_work(&vss_handle_request_work);
			return;
		}

		icmsghdrp->icflags = ICMSGHDRFLAG_TRANSACTION
			| ICMSGHDRFLAG_RESPONSE;

		vmbus_sendpacket(channel, recv_buffer,
				       recvlen, requestid,
				       VM_PKT_DATA_INBAND, 0);
	}

}

static void vss_on_reset(void)
{
	if (cancel_delayed_work_sync(&vss_timeout_work))
		vss_respond_to_host(HV_E_FAIL);
	vss_transaction.state = HVUTIL_DEVICE_INIT;
}

int
hv_vss_init(struct hv_util_service *srv)
{
	if (vmbus_proto_version < VERSION_WIN8_1) {
		pr_warn("Integration service 'Backup (volume snapshot)'"
			" not supported on this host version.\n");
		return -ENOTSUPP;
	}
	recv_buffer = srv->recv_buffer;
	vss_transaction.recv_channel = srv->channel;

	/*
	 * When this driver loads, the user level daemon that
	 * processes the host requests may not yet be running.
	 * Defer processing channel callbacks until the daemon
	 * has registered.
	 */
	vss_transaction.state = HVUTIL_DEVICE_INIT;

	hvt = hvutil_transport_init(vss_devname, CN_VSS_IDX, CN_VSS_VAL,
				    vss_on_msg, vss_on_reset);
	if (!hvt)
		return -EFAULT;

	return 0;
}

void hv_vss_deinit(void)
{
	vss_transaction.state = HVUTIL_DEVICE_DYING;
	cancel_delayed_work_sync(&vss_timeout_work);
	cancel_work_sync(&vss_handle_request_work);
	hvutil_transport_destroy(hvt);
}
Commit	Line	Data
96dd86fa S	1	/*
	2	* An implementation of host initiated guest snapshot.
	3	*
	4	*
	5	* Copyright (C) 2013, Microsoft, Inc.
	6	* Author : K. Y. Srinivasan <kys@microsoft.com>
	7	*
	8	* This program is free software; you can redistribute it and/or modify it
	9	* under the terms of the GNU General Public License version 2 as published
	10	* by the Free Software Foundation.
	11	*
	12	* This program is distributed in the hope that it will be useful, but
	13	* WITHOUT ANY WARRANTY; without even the implied warranty of
	14	* MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
	15	* NON INFRINGEMENT. See the GNU General Public License for more
	16	* details.
	17	*
	18	*/
	19	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
	20
	21	#include <linux/net.h>
	22	#include <linux/nls.h>
	23	#include <linux/connector.h>
	24	#include <linux/workqueue.h>
	25	#include <linux/hyperv.h>
	26
3647a83d	27	#include "hyperv_vmbus.h"
6472f80a	28	#include "hv_utils_transport.h"
3647a83d	29
6741335b S	30	#define VSS_MAJOR 5
6741335b S	31	#define VSS_MINOR 0
3a491605	32	#define VSS_VERSION (VSS_MAJOR << 16 \| VSS_MINOR)
6741335b	33
64914207	34	#define VSS_USERSPACE_TIMEOUT (msecs_to_jiffies(10 * 1000))
96dd86fa S	35
96dd86fa S	36	/*
086a6f68 VK	37	* Global state maintained for transaction that is being processed. For a class
	38	* of integration services, including the "VSS service", the specified protocol
	39	* is a "request/response" protocol which means that there can only be single
	40	* outstanding transaction from the host at any given point in time. We use
	41	* this to simplify memory management in this driver - we cache and process
	42	* only one message at a time.
96dd86fa	43	*
086a6f68 VK	44	* While the request/response protocol is guaranteed by the host, we further
	45	* ensure this by serializing packet processing in this driver - we do not
	46	* read additional packets from the VMBUs until the current packet is fully
	47	* handled.
96dd86fa S	48	*/
	49
	50	static struct {
086a6f68	51	int state; /* hvutil_device_state */
96dd86fa S	52	int recv_len; /* number of bytes received. */
	53	struct vmbus_channel recv_channel; / chn we got the request */
	54	u64 recv_req_id; /* request ID. */
	55	struct hv_vss_msg msg; / current message */
	56	} vss_transaction;
	57
	58
	59	static void vss_respond_to_host(int error);
	60
cd8dc054 VK	61	/*
	62	* This state maintains the version number registered by the daemon.
	63	*/
	64	static int dm_reg_value;
	65
6472f80a	66	static const char vss_devname[] = "vmbus/hv_vss";
96dd86fa	67	static __u8 *recv_buffer;
6472f80a	68	static struct hvutil_transport *hvt;
96dd86fa	69
64914207	70	static void vss_timeout_func(struct work_struct *dummy);
497af84b	71	static void vss_handle_request(struct work_struct *dummy);
64914207 VK	72
64914207 VK	73	static DECLARE_DELAYED_WORK(vss_timeout_work, vss_timeout_func);
497af84b	74	static DECLARE_WORK(vss_handle_request_work, vss_handle_request);
96dd86fa	75
3cace4a6 OH	76	static void vss_poll_wrapper(void *channel)
	77	{
	78	/* Transaction is finished, reset the state here to avoid races. */
	79	vss_transaction.state = HVUTIL_READY;
	80	hv_vss_onchannelcallback(channel);
	81	}
	82
96dd86fa S	83	/*
	84	* Callback when data is received from user mode.
	85	*/
	86
64914207 VK	87	static void vss_timeout_func(struct work_struct *dummy)
	88	{
	89	/*
	90	* Timeout waiting for userspace component to reply happened.
	91	*/
	92	pr_warn("VSS: timeout waiting for daemon to reply\n");
	93	vss_respond_to_host(HV_E_FAIL);
38c06c29	94
3cace4a6	95	hv_poll_channel(vss_transaction.recv_channel, vss_poll_wrapper);
64914207 VK	96	}
64914207 VK	97
e0fa3e5e VK	98	static void vss_register_done(void)
	99	{
	100	hv_poll_channel(vss_transaction.recv_channel, vss_poll_wrapper);
	101	pr_debug("VSS: userspace daemon registered\n");
	102	}
	103
cd8dc054 VK	104	static int vss_handle_handshake(struct hv_vss_msg *vss_msg)
	105	{
	106	u32 our_ver = VSS_OP_REGISTER1;
	107
	108	switch (vss_msg->vss_hdr.operation) {
	109	case VSS_OP_REGISTER:
	110	/* Daemon doesn't expect us to reply */
	111	dm_reg_value = VSS_OP_REGISTER;
	112	break;
	113	case VSS_OP_REGISTER1:
e0fa3e5e VK	114	/* Daemon expects us to reply with our own version */
	115	if (hvutil_transport_send(hvt, &our_ver, sizeof(our_ver),
	116	vss_register_done))
cd8dc054 VK	117	return -EFAULT;
	118	dm_reg_value = VSS_OP_REGISTER1;
	119	break;
	120	default:
	121	return -EINVAL;
	122	}
e0fa3e5e	123	pr_debug("VSS: userspace daemon ver. %d connected\n", dm_reg_value);
cd8dc054 VK	124	return 0;
	125	}
	126
6472f80a	127	static int vss_on_msg(void *msg, int len)
96dd86fa	128	{
6472f80a	129	struct hv_vss_msg vss_msg = (struct hv_vss_msg )msg;
96dd86fa	130
6472f80a VK	131	if (len != sizeof(*vss_msg))
6472f80a VK	132	return -EINVAL;
96dd86fa	133
cd8dc054 VK	134	if (vss_msg->vss_hdr.operation == VSS_OP_REGISTER \|\|
	135	vss_msg->vss_hdr.operation == VSS_OP_REGISTER1) {
	136	/*
	137	* Don't process registration messages if we're in the middle
	138	* of a transaction processing.
	139	*/
	140	if (vss_transaction.state > HVUTIL_READY)
	141	return -EINVAL;
	142	return vss_handle_handshake(vss_msg);
086a6f68 VK	143	} else if (vss_transaction.state == HVUTIL_USERSPACE_REQ) {
086a6f68 VK	144	vss_transaction.state = HVUTIL_USERSPACE_RECV;
db886e4d AN	145
	146	if (vss_msg->vss_hdr.operation == VSS_OP_HOT_BACKUP)
	147	vss_transaction.msg->vss_cf.flags =
	148	VSS_HBU_NO_AUTO_RECOVERY;
	149
086a6f68 VK	150	if (cancel_delayed_work_sync(&vss_timeout_work)) {
	151	vss_respond_to_host(vss_msg->error);
	152	/* Transaction is finished, reset the state. */
3cace4a6 OH	153	hv_poll_channel(vss_transaction.recv_channel,
3cace4a6 OH	154	vss_poll_wrapper);
086a6f68 VK	155	}
	156	} else {
	157	/* This is a spurious call! */
	158	pr_warn("VSS: Transaction not active\n");
6472f80a	159	return -EINVAL;
96dd86fa	160	}
6472f80a	161	return 0;
96dd86fa S	162	}
96dd86fa S	163
497af84b	164	static void vss_send_op(void)
96dd86fa S	165	{
96dd86fa S	166	int op = vss_transaction.msg->vss_hdr.operation;
8d9560eb	167	int rc;
96dd86fa S	168	struct hv_vss_msg *vss_msg;
96dd86fa S	169
086a6f68 VK	170	/* The transaction state is wrong. */
	171	if (vss_transaction.state != HVUTIL_HOSTMSG_RECEIVED)
	172	return;
	173
6472f80a VK	174	vss_msg = kzalloc(sizeof(*vss_msg), GFP_KERNEL);
6472f80a VK	175	if (!vss_msg)
96dd86fa S	176	return;
96dd86fa S	177
96dd86fa	178	vss_msg->vss_hdr.operation = op;
96dd86fa	179
086a6f68	180	vss_transaction.state = HVUTIL_USERSPACE_REQ;
497af84b AN	181
	182	schedule_delayed_work(&vss_timeout_work, VSS_USERSPACE_TIMEOUT);
	183
e0fa3e5e	184	rc = hvutil_transport_send(hvt, vss_msg, sizeof(*vss_msg), NULL);
8d9560eb VK	185	if (rc) {
8d9560eb VK	186	pr_warn("VSS: failed to communicate to the daemon: %d\n", rc);
086a6f68	187	if (cancel_delayed_work_sync(&vss_timeout_work)) {
8d9560eb	188	vss_respond_to_host(HV_E_FAIL);
086a6f68 VK	189	vss_transaction.state = HVUTIL_READY;
086a6f68 VK	190	}
8d9560eb	191	}
086a6f68	192
6472f80a	193	kfree(vss_msg);
96dd86fa S	194
	195	return;
	196	}
	197
497af84b AN	198	static void vss_handle_request(struct work_struct *dummy)
	199	{
	200	switch (vss_transaction.msg->vss_hdr.operation) {
	201	/*
	202	* Initiate a "freeze/thaw" operation in the guest.
	203	* We respond to the host once the operation is complete.
	204	*
	205	* We send the message to the user space daemon and the operation is
	206	* performed in the daemon.
	207	*/
	208	case VSS_OP_THAW:
	209	case VSS_OP_FREEZE:
db886e4d	210	case VSS_OP_HOT_BACKUP:
497af84b AN	211	if (vss_transaction.state < HVUTIL_READY) {
	212	/* Userspace is not registered yet */
	213	vss_respond_to_host(HV_E_FAIL);
	214	return;
	215	}
	216	vss_transaction.state = HVUTIL_HOSTMSG_RECEIVED;
	217	vss_send_op();
	218	return;
497af84b AN	219	case VSS_OP_GET_DM_INFO:
	220	vss_transaction.msg->dm_info.flags = 0;
	221	break;
	222	default:
	223	break;
	224	}
	225
	226	vss_respond_to_host(0);
	227	hv_poll_channel(vss_transaction.recv_channel, vss_poll_wrapper);
	228	}
	229
96dd86fa S	230	/*
	231	* Send a response back to the host.
	232	*/
	233
	234	static void
	235	vss_respond_to_host(int error)
	236	{
	237	struct icmsg_hdr *icmsghdrp;
	238	u32 buf_len;
	239	struct vmbus_channel *channel;
	240	u64 req_id;
	241
96dd86fa S	242	/*
	243	* Copy the global state for completing the transaction. Note that
	244	* only one transaction can be active at a time.
	245	*/
	246
	247	buf_len = vss_transaction.recv_len;
	248	channel = vss_transaction.recv_channel;
	249	req_id = vss_transaction.recv_req_id;
96dd86fa S	250
	251	icmsghdrp = (struct icmsg_hdr *)
	252	&recv_buffer[sizeof(struct vmbuspipe_hdr)];
	253
	254	if (channel->onchannel_callback == NULL)
	255	/*
	256	* We have raced with util driver being unloaded;
	257	* silently return.
	258	*/
	259	return;
	260
	261	icmsghdrp->status = error;
	262
	263	icmsghdrp->icflags = ICMSGHDRFLAG_TRANSACTION \| ICMSGHDRFLAG_RESPONSE;
	264
	265	vmbus_sendpacket(channel, recv_buffer, buf_len, req_id,
	266	VM_PKT_DATA_INBAND, 0);
	267
	268	}
	269
	270	/*
	271	* This callback is invoked when we get a VSS message from the host.
	272	* The host ensures that only one VSS transaction can be active at a time.
	273	*/
	274
	275	void hv_vss_onchannelcallback(void *context)
	276	{
	277	struct vmbus_channel *channel = context;
	278	u32 recvlen;
	279	u64 requestid;
	280	struct hv_vss_msg *vss_msg;
	281
	282
	283	struct icmsg_hdr *icmsghdrp;
	284	struct icmsg_negotiate *negop = NULL;
	285
3cace4a6	286	if (vss_transaction.state > HVUTIL_READY)
96dd86fa	287	return;
96dd86fa S	288
	289	vmbus_recvpacket(channel, recv_buffer, PAGE_SIZE * 2, &recvlen,
	290	&requestid);
	291
	292	if (recvlen > 0) {
	293	icmsghdrp = (struct icmsg_hdr *)&recv_buffer[
	294	sizeof(struct vmbuspipe_hdr)];
	295
	296	if (icmsghdrp->icmsgtype == ICMSGTYPE_NEGOTIATE) {
	297	vmbus_prep_negotiate_resp(icmsghdrp, negop,
3a491605 S	298	recv_buffer, UTIL_FW_VERSION,
3a491605 S	299	VSS_VERSION);
96dd86fa S	300	} else {
	301	vss_msg = (struct hv_vss_msg *)&recv_buffer[
	302	sizeof(struct vmbuspipe_hdr) +
	303	sizeof(struct icmsg_hdr)];
	304
	305	/*
	306	* Stash away this global state for completing the
	307	* transaction; note transactions are serialized.
	308	*/
	309
	310	vss_transaction.recv_len = recvlen;
96dd86fa	311	vss_transaction.recv_req_id = requestid;
96dd86fa S	312	vss_transaction.msg = (struct hv_vss_msg *)vss_msg;
96dd86fa S	313
497af84b AN	314	schedule_work(&vss_handle_request_work);
497af84b AN	315	return;
96dd86fa S	316	}
	317
	318	icmsghdrp->icflags = ICMSGHDRFLAG_TRANSACTION
	319	\| ICMSGHDRFLAG_RESPONSE;
	320
	321	vmbus_sendpacket(channel, recv_buffer,
	322	recvlen, requestid,
	323	VM_PKT_DATA_INBAND, 0);
	324	}
	325
	326	}
	327
6472f80a VK	328	static void vss_on_reset(void)
	329	{
	330	if (cancel_delayed_work_sync(&vss_timeout_work))
	331	vss_respond_to_host(HV_E_FAIL);
	332	vss_transaction.state = HVUTIL_DEVICE_INIT;
	333	}
	334
96dd86fa S	335	int
	336	hv_vss_init(struct hv_util_service *srv)
	337	{
ed9ba608 OH	338	if (vmbus_proto_version < VERSION_WIN8_1) {
	339	pr_warn("Integration service 'Backup (volume snapshot)'"
	340	" not supported on this host version.\n");
	341	return -ENOTSUPP;
	342	}
96dd86fa	343	recv_buffer = srv->recv_buffer;
b9830d12	344	vss_transaction.recv_channel = srv->channel;
96dd86fa S	345
	346	/*
	347	* When this driver loads, the user level daemon that
	348	* processes the host requests may not yet be running.
	349	* Defer processing channel callbacks until the daemon
	350	* has registered.
	351	*/
086a6f68 VK	352	vss_transaction.state = HVUTIL_DEVICE_INIT;
086a6f68 VK	353
6472f80a VK	354	hvt = hvutil_transport_init(vss_devname, CN_VSS_IDX, CN_VSS_VAL,
	355	vss_on_msg, vss_on_reset);
	356	if (!hvt)
	357	return -EFAULT;
	358
96dd86fa S	359	return 0;
	360	}
	361
	362	void hv_vss_deinit(void)
	363	{
086a6f68	364	vss_transaction.state = HVUTIL_DEVICE_DYING;
64914207	365	cancel_delayed_work_sync(&vss_timeout_work);
497af84b	366	cancel_work_sync(&vss_handle_request_work);
6472f80a	367	hvutil_transport_destroy(hvt);
96dd86fa	368	}