drivers/staging/hv/storvsc.c - linux - Git at Google

 /*
  * 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>
  *   K. Y. Srinivasan <kys@microsoft.com>
  *
  */
 #include <linux/kernel.h>
 #include <linux/sched.h>
 #include <linux/completion.h>
 #include <linux/string.h>
 #include <linux/slab.h>
 #include <linux/mm.h>
 #include <linux/delay.h>

 #include "hyperv.h"
 #include "hyperv_storage.h"


 static inline struct storvsc_device *alloc_stor_device(struct hv_device *device)
 {
 	struct storvsc_device *stor_device;

 	stor_device = kzalloc(sizeof(struct storvsc_device), GFP_KERNEL);
 	if (!stor_device)
 		return NULL;

 	/* Set to 2 to allow both inbound and outbound traffics */
 	/* (ie get_stor_device() and must_get_stor_device()) to proceed. */
 	atomic_cmpxchg(&stor_device->ref_count, 0, 2);

 	init_waitqueue_head(&stor_device->waiting_to_drain);
 	stor_device->device = device;
 	device->ext = stor_device;

 	return stor_device;
 }

 static inline void free_stor_device(struct storvsc_device *device)
 {
 	kfree(device);
 }

 /* Get the stordevice object iff exists and its refcount > 0 */
 static inline struct storvsc_device *must_get_stor_device(
 					struct hv_device *device)
 {
 	struct storvsc_device *stor_device;

 	stor_device = (struct storvsc_device *)device->ext;
 	if (stor_device && atomic_read(&stor_device->ref_count))
 		atomic_inc(&stor_device->ref_count);
 	else
 		stor_device = NULL;

 	return stor_device;
 }

 /* Drop ref count to 1 to effectively disable get_stor_device() */
 static inline struct storvsc_device *release_stor_device(
 					struct hv_device *device)
 {
 	struct storvsc_device *stor_device;

 	stor_device = (struct storvsc_device *)device->ext;

 	/* Busy wait until the ref drop to 2, then set it to 1 */
 	while (atomic_cmpxchg(&stor_device->ref_count, 2, 1) != 2)
 		udelay(100);

 	return stor_device;
 }

 /* Drop ref count to 0. No one can use stor_device object. */
 static inline struct storvsc_device *final_release_stor_device(
 			struct hv_device *device)
 {
 	struct storvsc_device *stor_device;

 	stor_device = (struct storvsc_device *)device->ext;

 	/* Busy wait until the ref drop to 1, then set it to 0 */
 	while (atomic_cmpxchg(&stor_device->ref_count, 1, 0) != 1)
 		udelay(100);

 	device->ext = NULL;
 	return stor_device;
 }

 static int storvsc_channel_init(struct hv_device *device)
 {
 	struct storvsc_device *stor_device;
 	struct hv_storvsc_request *request;
 	struct vstor_packet *vstor_packet;
 	int ret, t;

 	stor_device = get_stor_device(device);
 	if (!stor_device)
 		return -1;

 	request = &stor_device->init_request;
 	vstor_packet = &request->vstor_packet;

 	/*
 	 * Now, initiate the vsc/vsp initialization protocol on the open
 	 * channel
 	 */
 	memset(request, 0, sizeof(struct hv_storvsc_request));
 	init_completion(&request->wait_event);
 	vstor_packet->operation = VSTOR_OPERATION_BEGIN_INITIALIZATION;
 	vstor_packet->flags = REQUEST_COMPLETION_FLAG;

 	DPRINT_INFO(STORVSC, "BEGIN_INITIALIZATION_OPERATION...");

 	ret = vmbus_sendpacket(device->channel, vstor_packet,
 			       sizeof(struct vstor_packet),
 			       (unsigned long)request,
 			       VM_PKT_DATA_INBAND,
 			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
 	if (ret != 0)
 		goto cleanup;

 	t = wait_for_completion_timeout(&request->wait_event, 5*HZ);
 	if (t == 0) {
 		ret = -ETIMEDOUT;
 		goto cleanup;
 	}

 	if (vstor_packet->operation != VSTOR_OPERATION_COMPLETE_IO ||
 	    vstor_packet->status != 0)
 		goto cleanup;

 	DPRINT_INFO(STORVSC, "QUERY_PROTOCOL_VERSION_OPERATION...");

 	/* reuse the packet for version range supported */
 	memset(vstor_packet, 0, sizeof(struct vstor_packet));
 	vstor_packet->operation = VSTOR_OPERATION_QUERY_PROTOCOL_VERSION;
 	vstor_packet->flags = REQUEST_COMPLETION_FLAG;

 	vstor_packet->version.major_minor = VMSTOR_PROTOCOL_VERSION_CURRENT;
 	FILL_VMSTOR_REVISION(vstor_packet->version.revision);

 	ret = vmbus_sendpacket(device->channel, vstor_packet,
 			       sizeof(struct vstor_packet),
 			       (unsigned long)request,
 			       VM_PKT_DATA_INBAND,
 			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
 	if (ret != 0)
 		goto cleanup;

 	t = wait_for_completion_timeout(&request->wait_event, 5*HZ);
 	if (t == 0) {
 		ret = -ETIMEDOUT;
 		goto cleanup;
 	}

 	/* TODO: Check returned version */
 	if (vstor_packet->operation != VSTOR_OPERATION_COMPLETE_IO ||
 	    vstor_packet->status != 0)
 		goto cleanup;

 	/* Query channel properties */
 	DPRINT_INFO(STORVSC, "QUERY_PROPERTIES_OPERATION...");

 	memset(vstor_packet, 0, sizeof(struct vstor_packet));
 	vstor_packet->operation = VSTOR_OPERATION_QUERY_PROPERTIES;
 	vstor_packet->flags = REQUEST_COMPLETION_FLAG;
 	vstor_packet->storage_channel_properties.port_number =
 					stor_device->port_number;

 	ret = vmbus_sendpacket(device->channel, vstor_packet,
 			       sizeof(struct vstor_packet),
 			       (unsigned long)request,
 			       VM_PKT_DATA_INBAND,
 			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);

 	if (ret != 0)
 		goto cleanup;

 	t = wait_for_completion_timeout(&request->wait_event, 5*HZ);
 	if (t == 0) {
 		ret = -ETIMEDOUT;
 		goto cleanup;
 	}

 	/* TODO: Check returned version */
 	if (vstor_packet->operation != VSTOR_OPERATION_COMPLETE_IO ||
 	    vstor_packet->status != 0)
 		goto cleanup;

 	stor_device->path_id = vstor_packet->storage_channel_properties.path_id;
 	stor_device->target_id
 		= vstor_packet->storage_channel_properties.target_id;

 	DPRINT_INFO(STORVSC, "END_INITIALIZATION_OPERATION...");

 	memset(vstor_packet, 0, sizeof(struct vstor_packet));
 	vstor_packet->operation = VSTOR_OPERATION_END_INITIALIZATION;
 	vstor_packet->flags = REQUEST_COMPLETION_FLAG;

 	ret = vmbus_sendpacket(device->channel, vstor_packet,
 			       sizeof(struct vstor_packet),
 			       (unsigned long)request,
 			       VM_PKT_DATA_INBAND,
 			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);

 	if (ret != 0)
 		goto cleanup;

 	t = wait_for_completion_timeout(&request->wait_event, 5*HZ);
 	if (t == 0) {
 		ret = -ETIMEDOUT;
 		goto cleanup;
 	}

 	if (vstor_packet->operation != VSTOR_OPERATION_COMPLETE_IO ||
 	    vstor_packet->status != 0)
 		goto cleanup;

 	DPRINT_INFO(STORVSC, "**** storage channel up and running!! ****");

 cleanup:
 	put_stor_device(device);
 	return ret;
 }

 static void storvsc_on_io_completion(struct hv_device *device,
 				  struct vstor_packet *vstor_packet,
 				  struct hv_storvsc_request *request)
 {
 	struct storvsc_device *stor_device;
 	struct vstor_packet *stor_pkt;

 	stor_device = must_get_stor_device(device);
 	if (!stor_device)
 		return;

 	stor_pkt = &request->vstor_packet;


 	/* Copy over the status...etc */
 	stor_pkt->vm_srb.scsi_status = vstor_packet->vm_srb.scsi_status;
 	stor_pkt->vm_srb.srb_status = vstor_packet->vm_srb.srb_status;
 	stor_pkt->vm_srb.sense_info_length =
 	vstor_packet->vm_srb.sense_info_length;

 	if (vstor_packet->vm_srb.scsi_status != 0 ||
 		vstor_packet->vm_srb.srb_status != 1){
 		DPRINT_WARN(STORVSC,
 			    "cmd 0x%x scsi status 0x%x srb status 0x%x\n",
 			    stor_pkt->vm_srb.cdb[0],
 			    vstor_packet->vm_srb.scsi_status,
 			    vstor_packet->vm_srb.srb_status);
 	}

 	if ((vstor_packet->vm_srb.scsi_status & 0xFF) == 0x02) {
 		/* CHECK_CONDITION */
 		if (vstor_packet->vm_srb.srb_status & 0x80) {
 			/* autosense data available */
 			DPRINT_WARN(STORVSC, "storvsc pkt %p autosense data "
 				    "valid - len %d\n", request,
 				    vstor_packet->vm_srb.sense_info_length);

 			memcpy(request->sense_buffer,
 			       vstor_packet->vm_srb.sense_data,
 			       vstor_packet->vm_srb.sense_info_length);

 		}
 	}

 	stor_pkt->vm_srb.data_transfer_length =
 	vstor_packet->vm_srb.data_transfer_length;

 	request->on_io_completion(request);

 	if (atomic_dec_and_test(&stor_device->num_outstanding_req) &&
 		stor_device->drain_notify)
 		wake_up(&stor_device->waiting_to_drain);


 	put_stor_device(device);
 }

 static void storvsc_on_receive(struct hv_device *device,
 			     struct vstor_packet *vstor_packet,
 			     struct hv_storvsc_request *request)
 {
 	switch (vstor_packet->operation) {
 	case VSTOR_OPERATION_COMPLETE_IO:
 		storvsc_on_io_completion(device, vstor_packet, request);
 		break;
 	case VSTOR_OPERATION_REMOVE_DEVICE:
 		DPRINT_INFO(STORVSC, "REMOVE_DEVICE_OPERATION");
 		/* TODO: */
 		break;

 	default:
 		DPRINT_INFO(STORVSC, "Unknown operation received - %d",
 			    vstor_packet->operation);
 		break;
 	}
 }

 static void storvsc_on_channel_callback(void *context)
 {
 	struct hv_device *device = (struct hv_device *)context;
 	struct storvsc_device *stor_device;
 	u32 bytes_recvd;
 	u64 request_id;
 	unsigned char packet[ALIGN(sizeof(struct vstor_packet), 8)];
 	struct hv_storvsc_request *request;
 	int ret;


 	stor_device = must_get_stor_device(device);
 	if (!stor_device)
 		return;

 	do {
 		ret = vmbus_recvpacket(device->channel, packet,
 				       ALIGN(sizeof(struct vstor_packet), 8),
 				       &bytes_recvd, &request_id);
 		if (ret == 0 && bytes_recvd > 0) {

 			request = (struct hv_storvsc_request *)
 					(unsigned long)request_id;

 			if ((request == &stor_device->init_request) ||
 			    (request == &stor_device->reset_request)) {

 				memcpy(&request->vstor_packet, packet,
 				       sizeof(struct vstor_packet));
 				complete(&request->wait_event);
 			} else {
 				storvsc_on_receive(device,
 						(struct vstor_packet *)packet,
 						request);
 			}
 		} else {
 			break;
 		}
 	} while (1);

 	put_stor_device(device);
 	return;
 }

 static int storvsc_connect_to_vsp(struct hv_device *device, u32 ring_size)
 {
 	struct vmstorage_channel_properties props;
 	int ret;

 	memset(&props, 0, sizeof(struct vmstorage_channel_properties));

 	/* Open the channel */
 	ret = vmbus_open(device->channel,
 			 ring_size,
 			 ring_size,
 			 (void *)&props,
 			 sizeof(struct vmstorage_channel_properties),
 			 storvsc_on_channel_callback, device);

 	if (ret != 0)
 		return -1;

 	ret = storvsc_channel_init(device);

 	return ret;
 }

 int storvsc_dev_add(struct hv_device *device,
 					void *additional_info)
 {
 	struct storvsc_device *stor_device;
 	struct storvsc_device_info *device_info;
 	int ret = 0;

 	device_info = (struct storvsc_device_info *)additional_info;
 	stor_device = alloc_stor_device(device);
 	if (!stor_device) {
 		ret = -1;
 		goto cleanup;
 	}

 	/* Save the channel properties to our storvsc channel */

 	/* FIXME: */
 	/*
 	 * If we support more than 1 scsi channel, we need to set the
 	 * port number here to the scsi channel but how do we get the
 	 * scsi channel prior to the bus scan
 	 */

 	stor_device->port_number = device_info->port_number;
 	/* Send it back up */
 	ret = storvsc_connect_to_vsp(device, device_info->ring_buffer_size);

 	device_info->path_id = stor_device->path_id;
 	device_info->target_id = stor_device->target_id;

 cleanup:
 	return ret;
 }

 int storvsc_dev_remove(struct hv_device *device)
 {
 	struct storvsc_device *stor_device;

 	DPRINT_INFO(STORVSC, "disabling storage device (%p)...",
 		    device->ext);

 	stor_device = release_stor_device(device);

 	/*
 	 * At this point, all outbound traffic should be disable. We
 	 * only allow inbound traffic (responses) to proceed so that
 	 * outstanding requests can be completed.
 	 */

 	storvsc_wait_to_drain(stor_device);

 	stor_device = final_release_stor_device(device);

 	/* Close the channel */
 	vmbus_close(device->channel);

 	free_stor_device(stor_device);
 	return 0;
 }

 int storvsc_do_io(struct hv_device *device,
 			      struct hv_storvsc_request *request)
 {
 	struct storvsc_device *stor_device;
 	struct vstor_packet *vstor_packet;
 	int ret = 0;

 	vstor_packet = &request->vstor_packet;
 	stor_device = get_stor_device(device);

 	if (!stor_device)
 		return -2;


 	request->device  = device;


 	vstor_packet->flags |= REQUEST_COMPLETION_FLAG;

 	vstor_packet->vm_srb.length = sizeof(struct vmscsi_request);


 	vstor_packet->vm_srb.sense_info_length = SENSE_BUFFER_SIZE;


 	vstor_packet->vm_srb.data_transfer_length =
 	request->data_buffer.len;

 	vstor_packet->operation = VSTOR_OPERATION_EXECUTE_SRB;

 	if (request->data_buffer.len) {
 		ret = vmbus_sendpacket_multipagebuffer(device->channel,
 				&request->data_buffer,
 				vstor_packet,
 				sizeof(struct vstor_packet),
 				(unsigned long)request);
 	} else {
 		ret = vmbus_sendpacket(device->channel, vstor_packet,
 				       sizeof(struct vstor_packet),
 				       (unsigned long)request,
 				       VM_PKT_DATA_INBAND,
 				       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
 	}

 	if (ret != 0)
 		return ret;

 	atomic_inc(&stor_device->num_outstanding_req);

 	put_stor_device(device);
 	return ret;
 }

 /*
  * The channel properties uniquely specify how the device is to be
  * presented to the guest. Map this information for use by the block
  * driver. For Linux guests on Hyper-V, we emulate a scsi HBA in the guest
  * (storvsc_drv) and so scsi devices in the guest  are handled by
  * native upper level Linux drivers. Consequently, Hyper-V
  * block driver, while being a generic block driver, presently does not
  * deal with anything other than devices that would need to be presented
  * to the guest as an IDE disk.
  *
  * This function maps the channel properties as embedded in the input
  * parameter device_info onto information necessary to register the
  * corresponding block device.
  *
  * Currently, there is no way to stop the emulation of the block device
  * on the host side. And so, to prevent the native IDE drivers in Linux
  * from taking over these devices (to be managedby Hyper-V block
  * driver), we will take over if need be the major of the IDE controllers.
  *
  */

 int storvsc_get_major_info(struct storvsc_device_info *device_info,
 			    struct storvsc_major_info *major_info)
 {
 	static bool ide0_registered;
 	static bool ide1_registered;

 	/*
 	 * For now we only support IDE disks.
 	 */
 	major_info->devname = "ide";
 	major_info->diskname = "hd";

 	if (device_info->path_id) {
 		major_info->major = 22;
 		if (!ide1_registered) {
 			major_info->do_register = true;
 			ide1_registered = true;
 		} else
 			major_info->do_register = false;

 		if (device_info->target_id)
 			major_info->index = 3;
 		else
 			major_info->index = 2;

 		return 0;
 	} else {
 		major_info->major = 3;
 		if (!ide0_registered) {
 			major_info->do_register = true;
 			ide0_registered = true;
 		} else
 			major_info->do_register = false;

 		if (device_info->target_id)
 			major_info->index = 1;
 		else
 			major_info->index = 0;

 		return 0;
 	}

 	return -ENODEV;
 }
	/*
	* 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>
	* K. Y. Srinivasan <kys@microsoft.com>
	*
	*/
	#include <linux/kernel.h>
	#include <linux/sched.h>
	#include <linux/completion.h>
	#include <linux/string.h>
	#include <linux/slab.h>
	#include <linux/mm.h>
	#include <linux/delay.h>

	#include "hyperv.h"
	#include "hyperv_storage.h"


	static inline struct storvsc_device alloc_stor_device(struct hv_device device)
	{
	struct storvsc_device *stor_device;

	stor_device = kzalloc(sizeof(struct storvsc_device), GFP_KERNEL);
	if (!stor_device)
	return NULL;

	/* Set to 2 to allow both inbound and outbound traffics */
	/* (ie get_stor_device() and must_get_stor_device()) to proceed. */
	atomic_cmpxchg(&stor_device->ref_count, 0, 2);

	init_waitqueue_head(&stor_device->waiting_to_drain);
	stor_device->device = device;
	device->ext = stor_device;

	return stor_device;
	}

	static inline void free_stor_device(struct storvsc_device *device)
	{
	kfree(device);
	}

	/* Get the stordevice object iff exists and its refcount > 0 */
	static inline struct storvsc_device *must_get_stor_device(
	struct hv_device *device)
	{
	struct storvsc_device *stor_device;

	stor_device = (struct storvsc_device *)device->ext;
	if (stor_device && atomic_read(&stor_device->ref_count))
	atomic_inc(&stor_device->ref_count);
	else
	stor_device = NULL;

	return stor_device;
	}

	/* Drop ref count to 1 to effectively disable get_stor_device() */
	static inline struct storvsc_device *release_stor_device(
	struct hv_device *device)
	{
	struct storvsc_device *stor_device;

	stor_device = (struct storvsc_device *)device->ext;

	/* Busy wait until the ref drop to 2, then set it to 1 */
	while (atomic_cmpxchg(&stor_device->ref_count, 2, 1) != 2)
	udelay(100);

	return stor_device;
	}

	/* Drop ref count to 0. No one can use stor_device object. */
	static inline struct storvsc_device *final_release_stor_device(
	struct hv_device *device)
	{
	struct storvsc_device *stor_device;

	stor_device = (struct storvsc_device *)device->ext;

	/* Busy wait until the ref drop to 1, then set it to 0 */
	while (atomic_cmpxchg(&stor_device->ref_count, 1, 0) != 1)
	udelay(100);

	device->ext = NULL;
	return stor_device;
	}

	static int storvsc_channel_init(struct hv_device *device)
	{
	struct storvsc_device *stor_device;
	struct hv_storvsc_request *request;
	struct vstor_packet *vstor_packet;
	int ret, t;

	stor_device = get_stor_device(device);
	if (!stor_device)
	return -1;

	request = &stor_device->init_request;
	vstor_packet = &request->vstor_packet;

	/*
	* Now, initiate the vsc/vsp initialization protocol on the open
	* channel
	*/
	memset(request, 0, sizeof(struct hv_storvsc_request));
	init_completion(&request->wait_event);
	vstor_packet->operation = VSTOR_OPERATION_BEGIN_INITIALIZATION;
	vstor_packet->flags = REQUEST_COMPLETION_FLAG;

	DPRINT_INFO(STORVSC, "BEGIN_INITIALIZATION_OPERATION...");

	ret = vmbus_sendpacket(device->channel, vstor_packet,
	sizeof(struct vstor_packet),
	(unsigned long)request,
	VM_PKT_DATA_INBAND,
	VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
	if (ret != 0)
	goto cleanup;

	t = wait_for_completion_timeout(&request->wait_event, 5*HZ);
	if (t == 0) {
	ret = -ETIMEDOUT;
	goto cleanup;
	}

	if (vstor_packet->operation != VSTOR_OPERATION_COMPLETE_IO \|\|
	vstor_packet->status != 0)
	goto cleanup;

	DPRINT_INFO(STORVSC, "QUERY_PROTOCOL_VERSION_OPERATION...");

	/* reuse the packet for version range supported */
	memset(vstor_packet, 0, sizeof(struct vstor_packet));
	vstor_packet->operation = VSTOR_OPERATION_QUERY_PROTOCOL_VERSION;
	vstor_packet->flags = REQUEST_COMPLETION_FLAG;

	vstor_packet->version.major_minor = VMSTOR_PROTOCOL_VERSION_CURRENT;
	FILL_VMSTOR_REVISION(vstor_packet->version.revision);

	ret = vmbus_sendpacket(device->channel, vstor_packet,
	sizeof(struct vstor_packet),
	(unsigned long)request,
	VM_PKT_DATA_INBAND,
	VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
	if (ret != 0)
	goto cleanup;

	t = wait_for_completion_timeout(&request->wait_event, 5*HZ);
	if (t == 0) {
	ret = -ETIMEDOUT;
	goto cleanup;
	}

	/* TODO: Check returned version */
	if (vstor_packet->operation != VSTOR_OPERATION_COMPLETE_IO \|\|
	vstor_packet->status != 0)
	goto cleanup;

	/* Query channel properties */
	DPRINT_INFO(STORVSC, "QUERY_PROPERTIES_OPERATION...");

	memset(vstor_packet, 0, sizeof(struct vstor_packet));
	vstor_packet->operation = VSTOR_OPERATION_QUERY_PROPERTIES;
	vstor_packet->flags = REQUEST_COMPLETION_FLAG;
	vstor_packet->storage_channel_properties.port_number =
	stor_device->port_number;

	ret = vmbus_sendpacket(device->channel, vstor_packet,
	sizeof(struct vstor_packet),
	(unsigned long)request,
	VM_PKT_DATA_INBAND,
	VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);

	if (ret != 0)
	goto cleanup;

	t = wait_for_completion_timeout(&request->wait_event, 5*HZ);
	if (t == 0) {
	ret = -ETIMEDOUT;
	goto cleanup;
	}

	/* TODO: Check returned version */
	if (vstor_packet->operation != VSTOR_OPERATION_COMPLETE_IO \|\|
	vstor_packet->status != 0)
	goto cleanup;

	stor_device->path_id = vstor_packet->storage_channel_properties.path_id;
	stor_device->target_id
	= vstor_packet->storage_channel_properties.target_id;

	DPRINT_INFO(STORVSC, "END_INITIALIZATION_OPERATION...");

	memset(vstor_packet, 0, sizeof(struct vstor_packet));
	vstor_packet->operation = VSTOR_OPERATION_END_INITIALIZATION;
	vstor_packet->flags = REQUEST_COMPLETION_FLAG;

	ret = vmbus_sendpacket(device->channel, vstor_packet,
	sizeof(struct vstor_packet),
	(unsigned long)request,
	VM_PKT_DATA_INBAND,
	VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);

	if (ret != 0)
	goto cleanup;

	t = wait_for_completion_timeout(&request->wait_event, 5*HZ);
	if (t == 0) {
	ret = -ETIMEDOUT;
	goto cleanup;
	}

	if (vstor_packet->operation != VSTOR_OPERATION_COMPLETE_IO \|\|
	vstor_packet->status != 0)
	goto cleanup;

	DPRINT_INFO(STORVSC, "** storage channel up and running!! **");

	cleanup:
	put_stor_device(device);
	return ret;
	}

	static void storvsc_on_io_completion(struct hv_device *device,
	struct vstor_packet *vstor_packet,
	struct hv_storvsc_request *request)
	{
	struct storvsc_device *stor_device;
	struct vstor_packet *stor_pkt;

	stor_device = must_get_stor_device(device);
	if (!stor_device)
	return;

	stor_pkt = &request->vstor_packet;


	/* Copy over the status...etc */
	stor_pkt->vm_srb.scsi_status = vstor_packet->vm_srb.scsi_status;
	stor_pkt->vm_srb.srb_status = vstor_packet->vm_srb.srb_status;
	stor_pkt->vm_srb.sense_info_length =
	vstor_packet->vm_srb.sense_info_length;

	if (vstor_packet->vm_srb.scsi_status != 0 \|\|
	vstor_packet->vm_srb.srb_status != 1){
	DPRINT_WARN(STORVSC,
	"cmd 0x%x scsi status 0x%x srb status 0x%x\n",
	stor_pkt->vm_srb.cdb[0],
	vstor_packet->vm_srb.scsi_status,
	vstor_packet->vm_srb.srb_status);
	}

	if ((vstor_packet->vm_srb.scsi_status & 0xFF) == 0x02) {
	/* CHECK_CONDITION */
	if (vstor_packet->vm_srb.srb_status & 0x80) {
	/* autosense data available */
	DPRINT_WARN(STORVSC, "storvsc pkt %p autosense data "
	"valid - len %d\n", request,
	vstor_packet->vm_srb.sense_info_length);

	memcpy(request->sense_buffer,
	vstor_packet->vm_srb.sense_data,
	vstor_packet->vm_srb.sense_info_length);

	}
	}

	stor_pkt->vm_srb.data_transfer_length =
	vstor_packet->vm_srb.data_transfer_length;

	request->on_io_completion(request);

	if (atomic_dec_and_test(&stor_device->num_outstanding_req) &&
	stor_device->drain_notify)
	wake_up(&stor_device->waiting_to_drain);


	put_stor_device(device);
	}

	static void storvsc_on_receive(struct hv_device *device,
	struct vstor_packet *vstor_packet,
	struct hv_storvsc_request *request)
	{
	switch (vstor_packet->operation) {
	case VSTOR_OPERATION_COMPLETE_IO:
	storvsc_on_io_completion(device, vstor_packet, request);
	break;
	case VSTOR_OPERATION_REMOVE_DEVICE:
	DPRINT_INFO(STORVSC, "REMOVE_DEVICE_OPERATION");
	/* TODO: */
	break;

	default:
	DPRINT_INFO(STORVSC, "Unknown operation received - %d",
	vstor_packet->operation);
	break;
	}
	}

	static void storvsc_on_channel_callback(void *context)
	{
	struct hv_device device = (struct hv_device )context;
	struct storvsc_device *stor_device;
	u32 bytes_recvd;
	u64 request_id;
	unsigned char packet[ALIGN(sizeof(struct vstor_packet), 8)];
	struct hv_storvsc_request *request;
	int ret;


	stor_device = must_get_stor_device(device);
	if (!stor_device)
	return;

	do {
	ret = vmbus_recvpacket(device->channel, packet,
	ALIGN(sizeof(struct vstor_packet), 8),
	&bytes_recvd, &request_id);
	if (ret == 0 && bytes_recvd > 0) {

	request = (struct hv_storvsc_request *)
	(unsigned long)request_id;

	if ((request == &stor_device->init_request) \|\|
	(request == &stor_device->reset_request)) {

	memcpy(&request->vstor_packet, packet,
	sizeof(struct vstor_packet));
	complete(&request->wait_event);
	} else {
	storvsc_on_receive(device,
	(struct vstor_packet *)packet,
	request);
	}
	} else {
	break;
	}
	} while (1);

	put_stor_device(device);
	return;
	}

	static int storvsc_connect_to_vsp(struct hv_device *device, u32 ring_size)
	{
	struct vmstorage_channel_properties props;
	int ret;

	memset(&props, 0, sizeof(struct vmstorage_channel_properties));

	/* Open the channel */
	ret = vmbus_open(device->channel,
	ring_size,
	ring_size,
	(void *)&props,
	sizeof(struct vmstorage_channel_properties),
	storvsc_on_channel_callback, device);

	if (ret != 0)
	return -1;

	ret = storvsc_channel_init(device);

	return ret;
	}

	int storvsc_dev_add(struct hv_device *device,
	void *additional_info)
	{
	struct storvsc_device *stor_device;
	struct storvsc_device_info *device_info;
	int ret = 0;

	device_info = (struct storvsc_device_info *)additional_info;
	stor_device = alloc_stor_device(device);
	if (!stor_device) {
	ret = -1;
	goto cleanup;
	}

	/* Save the channel properties to our storvsc channel */

	/* FIXME: */
	/*
	* If we support more than 1 scsi channel, we need to set the
	* port number here to the scsi channel but how do we get the
	* scsi channel prior to the bus scan
	*/

	stor_device->port_number = device_info->port_number;
	/* Send it back up */
	ret = storvsc_connect_to_vsp(device, device_info->ring_buffer_size);

	device_info->path_id = stor_device->path_id;
	device_info->target_id = stor_device->target_id;

	cleanup:
	return ret;
	}

	int storvsc_dev_remove(struct hv_device *device)
	{
	struct storvsc_device *stor_device;

	DPRINT_INFO(STORVSC, "disabling storage device (%p)...",
	device->ext);

	stor_device = release_stor_device(device);

	/*
	* At this point, all outbound traffic should be disable. We
	* only allow inbound traffic (responses) to proceed so that
	* outstanding requests can be completed.
	*/

	storvsc_wait_to_drain(stor_device);

	stor_device = final_release_stor_device(device);

	/* Close the channel */
	vmbus_close(device->channel);

	free_stor_device(stor_device);
	return 0;
	}

	int storvsc_do_io(struct hv_device *device,
	struct hv_storvsc_request *request)
	{
	struct storvsc_device *stor_device;
	struct vstor_packet *vstor_packet;
	int ret = 0;

	vstor_packet = &request->vstor_packet;
	stor_device = get_stor_device(device);

	if (!stor_device)
	return -2;


	request->device = device;


	vstor_packet->flags \|= REQUEST_COMPLETION_FLAG;

	vstor_packet->vm_srb.length = sizeof(struct vmscsi_request);


	vstor_packet->vm_srb.sense_info_length = SENSE_BUFFER_SIZE;


	vstor_packet->vm_srb.data_transfer_length =
	request->data_buffer.len;

	vstor_packet->operation = VSTOR_OPERATION_EXECUTE_SRB;

	if (request->data_buffer.len) {
	ret = vmbus_sendpacket_multipagebuffer(device->channel,
	&request->data_buffer,
	vstor_packet,
	sizeof(struct vstor_packet),
	(unsigned long)request);
	} else {
	ret = vmbus_sendpacket(device->channel, vstor_packet,
	sizeof(struct vstor_packet),
	(unsigned long)request,
	VM_PKT_DATA_INBAND,
	VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
	}

	if (ret != 0)
	return ret;

	atomic_inc(&stor_device->num_outstanding_req);

	put_stor_device(device);
	return ret;
	}

	/*
	* The channel properties uniquely specify how the device is to be
	* presented to the guest. Map this information for use by the block
	* driver. For Linux guests on Hyper-V, we emulate a scsi HBA in the guest
	* (storvsc_drv) and so scsi devices in the guest are handled by
	* native upper level Linux drivers. Consequently, Hyper-V
	* block driver, while being a generic block driver, presently does not
	* deal with anything other than devices that would need to be presented
	* to the guest as an IDE disk.
	*
	* This function maps the channel properties as embedded in the input
	* parameter device_info onto information necessary to register the
	* corresponding block device.
	*
	* Currently, there is no way to stop the emulation of the block device
	* on the host side. And so, to prevent the native IDE drivers in Linux
	* from taking over these devices (to be managedby Hyper-V block
	* driver), we will take over if need be the major of the IDE controllers.
	*
	*/

	int storvsc_get_major_info(struct storvsc_device_info *device_info,
	struct storvsc_major_info *major_info)
	{
	static bool ide0_registered;
	static bool ide1_registered;

	/*
	* For now we only support IDE disks.
	*/
	major_info->devname = "ide";
	major_info->diskname = "hd";

	if (device_info->path_id) {
	major_info->major = 22;
	if (!ide1_registered) {
	major_info->do_register = true;
	ide1_registered = true;
	} else
	major_info->do_register = false;

	if (device_info->target_id)
	major_info->index = 3;
	else
	major_info->index = 2;

	return 0;
	} else {
	major_info->major = 3;
	if (!ide0_registered) {
	major_info->do_register = true;
	ide0_registered = true;
	} else
	major_info->do_register = false;

	if (device_info->target_id)
	major_info->index = 1;
	else
	major_info->index = 0;

	return 0;
	}

	return -ENODEV;
	}