[linux-2.6-block.git] / drivers / hv / hv_fcopy.c

/*
 * An implementation of file copy service.
 *
 * Copyright (C) 2014, Microsoft, Inc.
 *
 * Author : K. Y. Srinivasan <ksrinivasan@novell.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/nls.h>
#include <linux/workqueue.h>
#include <linux/hyperv.h>
#include <linux/sched.h>

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

#define WIN8_SRV_MAJOR		1
#define WIN8_SRV_MINOR		1
#define WIN8_SRV_VERSION	(WIN8_SRV_MAJOR << 16 | WIN8_SRV_MINOR)

/*
 * Global state maintained for transaction that is being processed.
 * For a class of integration services, including the "file copy 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 hv_fcopy_hdr  *fcopy_msg; /* current message */
	struct vmbus_channel *recv_channel; /* chn we got the request */
	u64 recv_req_id; /* request ID. */
	void *fcopy_context; /* for the channel callback */
} fcopy_transaction;

static void fcopy_respond_to_host(int error);
static void fcopy_send_data(struct work_struct *dummy);
static void fcopy_timeout_func(struct work_struct *dummy);
static DECLARE_DELAYED_WORK(fcopy_timeout_work, fcopy_timeout_func);
static DECLARE_WORK(fcopy_send_work, fcopy_send_data);
static const char fcopy_devname[] = "vmbus/hv_fcopy";
static u8 *recv_buffer;
static struct hvutil_transport *hvt;
/*
 * This state maintains the version number registered by the daemon.
 */
static int dm_reg_value;

static void fcopy_timeout_func(struct work_struct *dummy)
{
	/*
	 * If the timer fires, the user-mode component has not responded;
	 * process the pending transaction.
	 */
	fcopy_respond_to_host(HV_E_FAIL);

	/* Transaction is finished, reset the state. */
	if (fcopy_transaction.state > HVUTIL_READY)
		fcopy_transaction.state = HVUTIL_READY;

	hv_poll_channel(fcopy_transaction.fcopy_context,
			hv_fcopy_onchannelcallback);
}

static int fcopy_handle_handshake(u32 version)
{
	u32 our_ver = FCOPY_CURRENT_VERSION;

	switch (version) {
	case FCOPY_VERSION_0:
		/* Daemon doesn't expect us to reply */
		dm_reg_value = version;
		break;
	case FCOPY_VERSION_1:
		/* Daemon expects us to reply with our own version */
		if (hvutil_transport_send(hvt, &our_ver, sizeof(our_ver)))
			return -EFAULT;
		dm_reg_value = version;
		break;
	default:
		/*
		 * For now we will fail the registration.
		 * If and when we have multiple versions to
		 * deal with, we will be backward compatible.
		 * We will add this code when needed.
		 */
		return -EINVAL;
	}
	pr_debug("FCP: userspace daemon ver. %d registered\n", version);
	fcopy_transaction.state = HVUTIL_READY;
	hv_poll_channel(fcopy_transaction.fcopy_context,
			hv_fcopy_onchannelcallback);
	return 0;
}

static void fcopy_send_data(struct work_struct *dummy)
{
	struct hv_start_fcopy *smsg_out = NULL;
	int operation = fcopy_transaction.fcopy_msg->operation;
	struct hv_start_fcopy *smsg_in;
	void *out_src;
	int rc, out_len;

	/*
	 * The  strings sent from the host are encoded in
	 * in utf16; convert it to utf8 strings.
	 * The host assures us that the utf16 strings will not exceed
	 * the max lengths specified. We will however, reserve room
	 * for the string terminating character - in the utf16s_utf8s()
	 * function we limit the size of the buffer where the converted
	 * string is placed to W_MAX_PATH -1 to guarantee
	 * that the strings can be properly terminated!
	 */

	switch (operation) {
	case START_FILE_COPY:
		out_len = sizeof(struct hv_start_fcopy);
		smsg_out = kzalloc(sizeof(*smsg_out), GFP_KERNEL);
		if (!smsg_out)
			return;

		smsg_out->hdr.operation = operation;
		smsg_in = (struct hv_start_fcopy *)fcopy_transaction.fcopy_msg;

		utf16s_to_utf8s((wchar_t *)smsg_in->file_name, W_MAX_PATH,
				UTF16_LITTLE_ENDIAN,
				(__u8 *)&smsg_out->file_name, W_MAX_PATH - 1);

		utf16s_to_utf8s((wchar_t *)smsg_in->path_name, W_MAX_PATH,
				UTF16_LITTLE_ENDIAN,
				(__u8 *)&smsg_out->path_name, W_MAX_PATH - 1);

		smsg_out->copy_flags = smsg_in->copy_flags;
		smsg_out->file_size = smsg_in->file_size;
		out_src = smsg_out;
		break;

	default:
		out_src = fcopy_transaction.fcopy_msg;
		out_len = fcopy_transaction.recv_len;
		break;
	}

	fcopy_transaction.state = HVUTIL_USERSPACE_REQ;
	rc = hvutil_transport_send(hvt, out_src, out_len);
	if (rc) {
		pr_debug("FCP: failed to communicate to the daemon: %d\n", rc);
		if (cancel_delayed_work_sync(&fcopy_timeout_work)) {
			fcopy_respond_to_host(HV_E_FAIL);
			fcopy_transaction.state = HVUTIL_READY;
		}
	}
	kfree(smsg_out);

	return;
}

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

static void
fcopy_respond_to_host(int error)
{
	struct icmsg_hdr *icmsghdr;
	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. This is guaranteed
	 * by the file copy protocol implemented by the host. Furthermore,
	 * the "transaction active" state we maintain ensures that there can
	 * only be one active transaction at a time.
	 */

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

	icmsghdr = (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;

	icmsghdr->status = error;
	icmsghdr->icflags = ICMSGHDRFLAG_TRANSACTION | ICMSGHDRFLAG_RESPONSE;
	vmbus_sendpacket(channel, recv_buffer, buf_len, req_id,
				VM_PKT_DATA_INBAND, 0);
}

void hv_fcopy_onchannelcallback(void *context)
{
	struct vmbus_channel *channel = context;
	u32 recvlen;
	u64 requestid;
	struct hv_fcopy_hdr *fcopy_msg;
	struct icmsg_hdr *icmsghdr;
	struct icmsg_negotiate *negop = NULL;
	int util_fw_version;
	int fcopy_srv_version;

	if (fcopy_transaction.state > HVUTIL_READY) {
		/*
		 * We will defer processing this callback once
		 * the current transaction is complete.
		 */
		fcopy_transaction.fcopy_context = context;
		return;
	}
	fcopy_transaction.fcopy_context = NULL;

	vmbus_recvpacket(channel, recv_buffer, PAGE_SIZE * 2, &recvlen,
			 &requestid);
	if (recvlen <= 0)
		return;

	icmsghdr = (struct icmsg_hdr *)&recv_buffer[
			sizeof(struct vmbuspipe_hdr)];
	if (icmsghdr->icmsgtype == ICMSGTYPE_NEGOTIATE) {
		util_fw_version = UTIL_FW_VERSION;
		fcopy_srv_version = WIN8_SRV_VERSION;
		vmbus_prep_negotiate_resp(icmsghdr, negop, recv_buffer,
				util_fw_version, fcopy_srv_version);
	} else {
		fcopy_msg = (struct hv_fcopy_hdr *)&recv_buffer[
				sizeof(struct vmbuspipe_hdr) +
				sizeof(struct icmsg_hdr)];

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

		fcopy_transaction.recv_len = recvlen;
		fcopy_transaction.recv_channel = channel;
		fcopy_transaction.recv_req_id = requestid;
		fcopy_transaction.fcopy_msg = fcopy_msg;

		if (fcopy_transaction.state < HVUTIL_READY) {
			/* Userspace is not registered yet */
			fcopy_respond_to_host(HV_E_FAIL);
			return;
		}
		fcopy_transaction.state = HVUTIL_HOSTMSG_RECEIVED;

		/*
		 * Send the information to the user-level daemon.
		 */
		schedule_work(&fcopy_send_work);
		schedule_delayed_work(&fcopy_timeout_work, 5*HZ);
		return;
	}
	icmsghdr->icflags = ICMSGHDRFLAG_TRANSACTION | ICMSGHDRFLAG_RESPONSE;
	vmbus_sendpacket(channel, recv_buffer, recvlen, requestid,
			VM_PKT_DATA_INBAND, 0);
}

/* Callback when data is received from userspace */
static int fcopy_on_msg(void *msg, int len)
{
	int *val = (int *)msg;

	if (len != sizeof(int))
		return -EINVAL;

	if (fcopy_transaction.state == HVUTIL_DEVICE_INIT)
		return fcopy_handle_handshake(*val);

	if (fcopy_transaction.state != HVUTIL_USERSPACE_REQ)
		return -EINVAL;

	/*
	 * Complete the transaction by forwarding the result
	 * to the host. But first, cancel the timeout.
	 */
	if (cancel_delayed_work_sync(&fcopy_timeout_work)) {
		fcopy_transaction.state = HVUTIL_USERSPACE_RECV;
		fcopy_respond_to_host(*val);
		fcopy_transaction.state = HVUTIL_READY;
		hv_poll_channel(fcopy_transaction.fcopy_context,
				hv_fcopy_onchannelcallback);
	}

	return 0;
}

static void fcopy_on_reset(void)
{
	/*
	 * The daemon has exited; reset the state.
	 */
	fcopy_transaction.state = HVUTIL_DEVICE_INIT;

	if (cancel_delayed_work_sync(&fcopy_timeout_work))
		fcopy_respond_to_host(HV_E_FAIL);
}

int hv_fcopy_init(struct hv_util_service *srv)
{
	recv_buffer = srv->recv_buffer;

	/*
	 * 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.
	 */
	fcopy_transaction.state = HVUTIL_DEVICE_INIT;

	hvt = hvutil_transport_init(fcopy_devname, 0, 0,
				    fcopy_on_msg, fcopy_on_reset);
	if (!hvt)
		return -EFAULT;

	return 0;
}

void hv_fcopy_deinit(void)
{
	fcopy_transaction.state = HVUTIL_DEVICE_DYING;
	cancel_delayed_work_sync(&fcopy_timeout_work);
	hvutil_transport_destroy(hvt);
}
Commit	Line	Data
01325476 S	1	/*
	2	* An implementation of file copy service.
	3	*
	4	* Copyright (C) 2014, Microsoft, Inc.
	5	*
	6	* Author : K. Y. Srinivasan <ksrinivasan@novell.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
	20	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
	21
01325476 S	22	#include <linux/nls.h>
01325476 S	23	#include <linux/workqueue.h>
01325476 S	24	#include <linux/hyperv.h>
01325476 S	25	#include <linux/sched.h>
01325476 S	26
01325476 S	27	#include "hyperv_vmbus.h"
c7e490fc	28	#include "hv_utils_transport.h"
01325476 S	29
	30	#define WIN8_SRV_MAJOR 1
	31	#define WIN8_SRV_MINOR 1
	32	#define WIN8_SRV_VERSION (WIN8_SRV_MAJOR << 16 \| WIN8_SRV_MINOR)
	33
	34	/*
	35	* Global state maintained for transaction that is being processed.
	36	* For a class of integration services, including the "file copy service",
	37	* the specified protocol is a "request/response" protocol which means that
	38	* there can only be single outstanding transaction from the host at any
	39	* given point in time. We use this to simplify memory management in this
	40	* driver - we cache and process only one message at a time.
	41	*
	42	* While the request/response protocol is guaranteed by the host, we further
	43	* ensure this by serializing packet processing in this driver - we do not
	44	* read additional packets from the VMBUs until the current packet is fully
	45	* handled.
01325476 S	46	*/
	47
	48	static struct {
4c93cccc	49	int state; /* hvutil_device_state */
01325476 S	50	int recv_len; /* number of bytes received. */
01325476 S	51	struct hv_fcopy_hdr fcopy_msg; / current message */
01325476 S	52	struct vmbus_channel recv_channel; / chn we got the request */
	53	u64 recv_req_id; /* request ID. */
	54	void fcopy_context; / for the channel callback */
01325476 S	55	} fcopy_transaction;
01325476 S	56
01325476	57	static void fcopy_respond_to_host(int error);
c7e490fc	58	static void fcopy_send_data(struct work_struct *dummy);
1d072339 VK	59	static void fcopy_timeout_func(struct work_struct *dummy);
1d072339 VK	60	static DECLARE_DELAYED_WORK(fcopy_timeout_work, fcopy_timeout_func);
c7e490fc VK	61	static DECLARE_WORK(fcopy_send_work, fcopy_send_data);
c7e490fc VK	62	static const char fcopy_devname[] = "vmbus/hv_fcopy";
01325476	63	static u8 *recv_buffer;
c7e490fc	64	static struct hvutil_transport *hvt;
a4d1ee5b VK	65	/*
	66	* This state maintains the version number registered by the daemon.
	67	*/
	68	static int dm_reg_value;
01325476	69
1d072339	70	static void fcopy_timeout_func(struct work_struct *dummy)
01325476 S	71	{
	72	/*
	73	* If the timer fires, the user-mode component has not responded;
	74	* process the pending transaction.
	75	*/
	76	fcopy_respond_to_host(HV_E_FAIL);
d9b16529	77
4c93cccc VK	78	/* Transaction is finished, reset the state. */
	79	if (fcopy_transaction.state > HVUTIL_READY)
	80	fcopy_transaction.state = HVUTIL_READY;
	81
242f3122 VK	82	hv_poll_channel(fcopy_transaction.fcopy_context,
242f3122 VK	83	hv_fcopy_onchannelcallback);
01325476 S	84	}
	85
	86	static int fcopy_handle_handshake(u32 version)
	87	{
a4d1ee5b VK	88	u32 our_ver = FCOPY_CURRENT_VERSION;
a4d1ee5b VK	89
01325476	90	switch (version) {
a4d1ee5b VK	91	case FCOPY_VERSION_0:
	92	/* Daemon doesn't expect us to reply */
	93	dm_reg_value = version;
	94	break;
	95	case FCOPY_VERSION_1:
	96	/* Daemon expects us to reply with our own version */
	97	if (hvutil_transport_send(hvt, &our_ver, sizeof(our_ver)))
	98	return -EFAULT;
	99	dm_reg_value = version;
01325476 S	100	break;
	101	default:
	102	/*
	103	* For now we will fail the registration.
	104	* If and when we have multiple versions to
	105	* deal with, we will be backward compatible.
	106	* We will add this code when needed.
	107	*/
	108	return -EINVAL;
	109	}
7c959127	110	pr_debug("FCP: userspace daemon ver. %d registered\n", version);
4c93cccc	111	fcopy_transaction.state = HVUTIL_READY;
242f3122 VK	112	hv_poll_channel(fcopy_transaction.fcopy_context,
242f3122 VK	113	hv_fcopy_onchannelcallback);
01325476 S	114	return 0;
	115	}
	116
c7e490fc	117	static void fcopy_send_data(struct work_struct *dummy)
01325476	118	{
25ef06fe	119	struct hv_start_fcopy *smsg_out = NULL;
01325476 S	120	int operation = fcopy_transaction.fcopy_msg->operation;
01325476 S	121	struct hv_start_fcopy *smsg_in;
c7e490fc VK	122	void *out_src;
c7e490fc VK	123	int rc, out_len;
01325476 S	124
	125	/*
	126	* The strings sent from the host are encoded in
	127	* in utf16; convert it to utf8 strings.
	128	* The host assures us that the utf16 strings will not exceed
	129	* the max lengths specified. We will however, reserve room
	130	* for the string terminating character - in the utf16s_utf8s()
	131	* function we limit the size of the buffer where the converted
	132	* string is placed to W_MAX_PATH -1 to guarantee
	133	* that the strings can be properly terminated!
	134	*/
	135
	136	switch (operation) {
	137	case START_FILE_COPY:
c7e490fc	138	out_len = sizeof(struct hv_start_fcopy);
25ef06fe VK	139	smsg_out = kzalloc(sizeof(*smsg_out), GFP_KERNEL);
	140	if (!smsg_out)
	141	return;
	142
	143	smsg_out->hdr.operation = operation;
01325476 S	144	smsg_in = (struct hv_start_fcopy *)fcopy_transaction.fcopy_msg;
	145
	146	utf16s_to_utf8s((wchar_t *)smsg_in->file_name, W_MAX_PATH,
	147	UTF16_LITTLE_ENDIAN,
25ef06fe	148	(__u8 *)&smsg_out->file_name, W_MAX_PATH - 1);
01325476 S	149
	150	utf16s_to_utf8s((wchar_t *)smsg_in->path_name, W_MAX_PATH,
	151	UTF16_LITTLE_ENDIAN,
25ef06fe	152	(__u8 *)&smsg_out->path_name, W_MAX_PATH - 1);
01325476	153
25ef06fe VK	154	smsg_out->copy_flags = smsg_in->copy_flags;
	155	smsg_out->file_size = smsg_in->file_size;
	156	out_src = smsg_out;
01325476 S	157	break;
	158
	159	default:
c7e490fc VK	160	out_src = fcopy_transaction.fcopy_msg;
c7e490fc VK	161	out_len = fcopy_transaction.recv_len;
01325476 S	162	break;
01325476 S	163	}
c7e490fc VK	164
	165	fcopy_transaction.state = HVUTIL_USERSPACE_REQ;
	166	rc = hvutil_transport_send(hvt, out_src, out_len);
	167	if (rc) {
	168	pr_debug("FCP: failed to communicate to the daemon: %d\n", rc);
	169	if (cancel_delayed_work_sync(&fcopy_timeout_work)) {
	170	fcopy_respond_to_host(HV_E_FAIL);
	171	fcopy_transaction.state = HVUTIL_READY;
	172	}
	173	}
25ef06fe VK	174	kfree(smsg_out);
25ef06fe VK	175
01325476 S	176	return;
	177	}
	178
	179	/*
	180	* Send a response back to the host.
	181	*/
	182
	183	static void
	184	fcopy_respond_to_host(int error)
	185	{
	186	struct icmsg_hdr *icmsghdr;
	187	u32 buf_len;
	188	struct vmbus_channel *channel;
	189	u64 req_id;
	190
	191	/*
	192	* Copy the global state for completing the transaction. Note that
	193	* only one transaction can be active at a time. This is guaranteed
	194	* by the file copy protocol implemented by the host. Furthermore,
	195	* the "transaction active" state we maintain ensures that there can
	196	* only be one active transaction at a time.
	197	*/
	198
	199	buf_len = fcopy_transaction.recv_len;
	200	channel = fcopy_transaction.recv_channel;
	201	req_id = fcopy_transaction.recv_req_id;
	202
01325476 S	203	icmsghdr = (struct icmsg_hdr *)
	204	&recv_buffer[sizeof(struct vmbuspipe_hdr)];
	205
	206	if (channel->onchannel_callback == NULL)
	207	/*
	208	* We have raced with util driver being unloaded;
	209	* silently return.
	210	*/
	211	return;
	212
	213	icmsghdr->status = error;
	214	icmsghdr->icflags = ICMSGHDRFLAG_TRANSACTION \| ICMSGHDRFLAG_RESPONSE;
	215	vmbus_sendpacket(channel, recv_buffer, buf_len, req_id,
	216	VM_PKT_DATA_INBAND, 0);
	217	}
	218
	219	void hv_fcopy_onchannelcallback(void *context)
	220	{
	221	struct vmbus_channel *channel = context;
	222	u32 recvlen;
	223	u64 requestid;
	224	struct hv_fcopy_hdr *fcopy_msg;
	225	struct icmsg_hdr *icmsghdr;
	226	struct icmsg_negotiate *negop = NULL;
	227	int util_fw_version;
	228	int fcopy_srv_version;
	229
4c93cccc	230	if (fcopy_transaction.state > HVUTIL_READY) {
01325476 S	231	/*
	232	* We will defer processing this callback once
	233	* the current transaction is complete.
	234	*/
	235	fcopy_transaction.fcopy_context = context;
	236	return;
	237	}
242f3122	238	fcopy_transaction.fcopy_context = NULL;
01325476 S	239
	240	vmbus_recvpacket(channel, recv_buffer, PAGE_SIZE * 2, &recvlen,
	241	&requestid);
	242	if (recvlen <= 0)
	243	return;
	244
	245	icmsghdr = (struct icmsg_hdr *)&recv_buffer[
	246	sizeof(struct vmbuspipe_hdr)];
	247	if (icmsghdr->icmsgtype == ICMSGTYPE_NEGOTIATE) {
	248	util_fw_version = UTIL_FW_VERSION;
	249	fcopy_srv_version = WIN8_SRV_VERSION;
	250	vmbus_prep_negotiate_resp(icmsghdr, negop, recv_buffer,
	251	util_fw_version, fcopy_srv_version);
	252	} else {
	253	fcopy_msg = (struct hv_fcopy_hdr *)&recv_buffer[
	254	sizeof(struct vmbuspipe_hdr) +
	255	sizeof(struct icmsg_hdr)];
	256
	257	/*
	258	* Stash away this global state for completing the
	259	* transaction; note transactions are serialized.
	260	*/
	261
01325476 S	262	fcopy_transaction.recv_len = recvlen;
	263	fcopy_transaction.recv_channel = channel;
	264	fcopy_transaction.recv_req_id = requestid;
	265	fcopy_transaction.fcopy_msg = fcopy_msg;
	266
4c93cccc VK	267	if (fcopy_transaction.state < HVUTIL_READY) {
	268	/* Userspace is not registered yet */
	269	fcopy_respond_to_host(HV_E_FAIL);
	270	return;
	271	}
	272	fcopy_transaction.state = HVUTIL_HOSTMSG_RECEIVED;
	273
01325476 S	274	/*
	275	* Send the information to the user-level daemon.
	276	*/
c7e490fc	277	schedule_work(&fcopy_send_work);
1d072339	278	schedule_delayed_work(&fcopy_timeout_work, 5*HZ);
01325476 S	279	return;
	280	}
	281	icmsghdr->icflags = ICMSGHDRFLAG_TRANSACTION \| ICMSGHDRFLAG_RESPONSE;
	282	vmbus_sendpacket(channel, recv_buffer, recvlen, requestid,
	283	VM_PKT_DATA_INBAND, 0);
	284	}
	285
c7e490fc VK	286	/* Callback when data is received from userspace */
c7e490fc VK	287	static int fcopy_on_msg(void *msg, int len)
01325476	288	{
c7e490fc	289	int val = (int )msg;
01325476	290
c7e490fc	291	if (len != sizeof(int))
01325476 S	292	return -EINVAL;
01325476 S	293
c7e490fc VK	294	if (fcopy_transaction.state == HVUTIL_DEVICE_INIT)
c7e490fc VK	295	return fcopy_handle_handshake(*val);
01325476	296
4c93cccc VK	297	if (fcopy_transaction.state != HVUTIL_USERSPACE_REQ)
	298	return -EINVAL;
	299
01325476 S	300	/*
	301	* Complete the transaction by forwarding the result
	302	* to the host. But first, cancel the timeout.
	303	*/
4c93cccc VK	304	if (cancel_delayed_work_sync(&fcopy_timeout_work)) {
4c93cccc VK	305	fcopy_transaction.state = HVUTIL_USERSPACE_RECV;
c7e490fc	306	fcopy_respond_to_host(*val);
4c93cccc	307	fcopy_transaction.state = HVUTIL_READY;
242f3122 VK	308	hv_poll_channel(fcopy_transaction.fcopy_context,
	309	hv_fcopy_onchannelcallback);
	310	}
01325476	311
01325476 S	312	return 0;
	313	}
	314
c7e490fc	315	static void fcopy_on_reset(void)
01325476 S	316	{
	317	/*
	318	* The daemon has exited; reset the state.
	319	*/
4c93cccc	320	fcopy_transaction.state = HVUTIL_DEVICE_INIT;
d9b16529	321
c7e490fc	322	if (cancel_delayed_work_sync(&fcopy_timeout_work))
d9b16529	323	fcopy_respond_to_host(HV_E_FAIL);
01325476 S	324	}
	325
	326	int hv_fcopy_init(struct hv_util_service *srv)
	327	{
	328	recv_buffer = srv->recv_buffer;
	329
	330	/*
	331	* When this driver loads, the user level daemon that
	332	* processes the host requests may not yet be running.
	333	* Defer processing channel callbacks until the daemon
	334	* has registered.
	335	*/
4c93cccc	336	fcopy_transaction.state = HVUTIL_DEVICE_INIT;
01325476	337
c7e490fc VK	338	hvt = hvutil_transport_init(fcopy_devname, 0, 0,
	339	fcopy_on_msg, fcopy_on_reset);
	340	if (!hvt)
	341	return -EFAULT;
	342
	343	return 0;
01325476 S	344	}
	345
	346	void hv_fcopy_deinit(void)
	347	{
4c93cccc	348	fcopy_transaction.state = HVUTIL_DEVICE_DYING;
1d072339	349	cancel_delayed_work_sync(&fcopy_timeout_work);
c7e490fc	350	hvutil_transport_destroy(hvt);
01325476	351	}