Merge tag 'staging-3.3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging

Pull big staging driver updates from Greg KH:
 "Here is the big drivers/staging/ merge for 3.4-rc1

  Lots of new driver updates here, with the addition of a few new ones,
  and only one moving out of the staging tree to the "real" part of the
  kernel (the hyperv scsi driver, acked by the scsi maintainer).

  There are also loads of cleanups, fixes, and other minor things in
  here, all self-contained in the drivers/staging/ tree.

  Overall we reversed the recent trend by adding more lines than we
  removed:
   379 files changed, 37952 insertions(+), 14153 deletions(-)"

* tag 'staging-3.3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging: (360 commits)
  staging/zmem: Use lockdep_assert_held instead of spin_is_locked
  Staging: rtl8187se: r8180_wx.c: Cleaned up comments
  Staging: rtl8187se: r8180_wx.c: Removed old comments
  Staging: rtl8187se: r8180_dm.c: Removed old comments
  Staging: android: ram_console.c:
  Staging: rtl8187se: r8180_dm.c: Fix comments
  Staging: rtl8187se: r8180_dm.c: Fix spacing issues
  Staging: rtl8187se: r8180_dm.c Fixed indentation issues
  Staging: rtl8187se: r8180_dm.c: Fix brackets
  Staging: rtl8187se: r8180_dm.c: Removed spaces before tab stop
  staging: vme: fix section mismatches in linux-next 20120314
  Staging: rtl8187se: r8180_core.c: Fix some long line issues
  Staging: rtl8187se: r8180_core.c: Fix some spacing issues
  Staging: rtl8187se: r8180_core.c: Removed trailing spaces
  staging: mei: remove driver internal versioning
  Staging: rtl8187se: r8180_core.c: Cleaned up if statement
  staging: ozwpan depends on NET
  staging: ozwpan: added maintainer for ozwpan driver
  staging/mei: propagate error codes up in the write flow
  drivers:staging:mei Fix some typos in staging/mei
  ...

3 files changed, 1558 insertions, 0 deletions

diff --git a/drivers/scsi/Kconfig b/drivers/scsi/Kconfig
index 16570aa84aac..d3d18e89cb57 100644
--- a/drivers/scsi/Kconfig
+++ b/drivers/scsi/Kconfig
@@ -662,6 +662,13 @@ config VMWARE_PVSCSI
 	  To compile this driver as a module, choose M here: the
 	  module will be called vmw_pvscsi.
 
+config HYPERV_STORAGE
+	tristate "Microsoft Hyper-V virtual storage driver"
+	depends on SCSI && HYPERV
+	default HYPERV
+	help
+	  Select this option to enable the Hyper-V virtual storage driver.
+
 config LIBFC
 	tristate "LibFC module"
 	select SCSI_FC_ATTRS
diff --git a/drivers/scsi/Makefile b/drivers/scsi/Makefile
index 2b887498be50..e4c1a69f8fab 100644
--- a/drivers/scsi/Makefile
+++ b/drivers/scsi/Makefile
@@ -142,6 +142,7 @@ obj-$(CONFIG_SCSI_BNX2_ISCSI)	+= libiscsi.o bnx2i/
 obj-$(CONFIG_BE2ISCSI)		+= libiscsi.o be2iscsi/
 obj-$(CONFIG_SCSI_PMCRAID)	+= pmcraid.o
 obj-$(CONFIG_VMWARE_PVSCSI)	+= vmw_pvscsi.o
+obj-$(CONFIG_HYPERV_STORAGE)	+= hv_storvsc.o
 
 obj-$(CONFIG_ARM)		+= arm/
 
@@ -170,6 +171,8 @@ scsi_mod-$(CONFIG_SCSI_PROC_FS)	+= scsi_proc.o
 scsi_mod-y			+= scsi_trace.o
 scsi_mod-$(CONFIG_PM)		+= scsi_pm.o
 
+hv_storvsc-y			:= storvsc_drv.o
+
 scsi_tgt-y			+= scsi_tgt_lib.o scsi_tgt_if.o
 
 sd_mod-objs	:= sd.o
diff --git a/drivers/scsi/storvsc_drv.c b/drivers/scsi/storvsc_drv.c
new file mode 100644
index 000000000000..695ffc36e02d
--- /dev/null
+++ b/drivers/scsi/storvsc_drv.c
@@ -0,0 +1,1548 @@
+/*
+ * 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/wait.h>
+#include <linux/sched.h>
+#include <linux/completion.h>
+#include <linux/string.h>
+#include <linux/mm.h>
+#include <linux/delay.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/hyperv.h>
+#include <linux/mempool.h>
+#include <scsi/scsi.h>
+#include <scsi/scsi_cmnd.h>
+#include <scsi/scsi_host.h>
+#include <scsi/scsi_device.h>
+#include <scsi/scsi_tcq.h>
+#include <scsi/scsi_eh.h>
+#include <scsi/scsi_devinfo.h>
+#include <scsi/scsi_dbg.h>
+
+/*
+ * All wire protocol details (storage protocol between the guest and the host)
+ * are consolidated here.
+ *
+ * Begin protocol definitions.
+ */
+
+/*
+ * Version history:
+ * V1 Beta: 0.1
+ * V1 RC < 2008/1/31: 1.0
+ * V1 RC > 2008/1/31:  2.0
+ * Win7: 4.2
+ */
+
+#define VMSTOR_CURRENT_MAJOR  4
+#define VMSTOR_CURRENT_MINOR  2
+
+
+/*  Packet structure describing virtual storage requests. */
+enum vstor_packet_operation {
+	VSTOR_OPERATION_COMPLETE_IO		= 1,
+	VSTOR_OPERATION_REMOVE_DEVICE		= 2,
+	VSTOR_OPERATION_EXECUTE_SRB		= 3,
+	VSTOR_OPERATION_RESET_LUN		= 4,
+	VSTOR_OPERATION_RESET_ADAPTER		= 5,
+	VSTOR_OPERATION_RESET_BUS		= 6,
+	VSTOR_OPERATION_BEGIN_INITIALIZATION	= 7,
+	VSTOR_OPERATION_END_INITIALIZATION	= 8,
+	VSTOR_OPERATION_QUERY_PROTOCOL_VERSION	= 9,
+	VSTOR_OPERATION_QUERY_PROPERTIES	= 10,
+	VSTOR_OPERATION_ENUMERATE_BUS		= 11,
+	VSTOR_OPERATION_MAXIMUM			= 11
+};
+
+/*
+ * Platform neutral description of a scsi request -
+ * this remains the same across the write regardless of 32/64 bit
+ * note: it's patterned off the SCSI_PASS_THROUGH structure
+ */
+#define STORVSC_MAX_CMD_LEN			0x10
+#define STORVSC_SENSE_BUFFER_SIZE		0x12
+#define STORVSC_MAX_BUF_LEN_WITH_PADDING	0x14
+
+struct vmscsi_request {
+	u16 length;
+	u8 srb_status;
+	u8 scsi_status;
+
+	u8  port_number;
+	u8  path_id;
+	u8  target_id;
+	u8  lun;
+
+	u8  cdb_length;
+	u8  sense_info_length;
+	u8  data_in;
+	u8  reserved;
+
+	u32 data_transfer_length;
+
+	union {
+		u8 cdb[STORVSC_MAX_CMD_LEN];
+		u8 sense_data[STORVSC_SENSE_BUFFER_SIZE];
+		u8 reserved_array[STORVSC_MAX_BUF_LEN_WITH_PADDING];
+	};
+} __attribute((packed));
+
+
+/*
+ * This structure is sent during the intialization phase to get the different
+ * properties of the channel.
+ */
+struct vmstorage_channel_properties {
+	u16 protocol_version;
+	u8  path_id;
+	u8 target_id;
+
+	/* Note: port number is only really known on the client side */
+	u32  port_number;
+	u32  flags;
+	u32   max_transfer_bytes;
+
+	/*
+	 * This id is unique for each channel and will correspond with
+	 * vendor specific data in the inquiry data.
+	 */
+
+	u64  unique_id;
+} __packed;
+
+/*  This structure is sent during the storage protocol negotiations. */
+struct vmstorage_protocol_version {
+	/* Major (MSW) and minor (LSW) version numbers. */
+	u16 major_minor;
+
+	/*
+	 * Revision number is auto-incremented whenever this file is changed
+	 * (See FILL_VMSTOR_REVISION macro above).  Mismatch does not
+	 * definitely indicate incompatibility--but it does indicate mismatched
+	 * builds.
+	 * This is only used on the windows side. Just set it to 0.
+	 */
+	u16 revision;
+} __packed;
+
+/* Channel Property Flags */
+#define STORAGE_CHANNEL_REMOVABLE_FLAG		0x1
+#define STORAGE_CHANNEL_EMULATED_IDE_FLAG	0x2
+
+struct vstor_packet {
+	/* Requested operation type */
+	enum vstor_packet_operation operation;
+
+	/*  Flags - see below for values */
+	u32 flags;
+
+	/* Status of the request returned from the server side. */
+	u32 status;
+
+	/* Data payload area */
+	union {
+		/*
+		 * Structure used to forward SCSI commands from the
+		 * client to the server.
+		 */
+		struct vmscsi_request vm_srb;
+
+		/* Structure used to query channel properties. */
+		struct vmstorage_channel_properties storage_channel_properties;
+
+		/* Used during version negotiations. */
+		struct vmstorage_protocol_version version;
+	};
+} __packed;
+
+/*
+ * Packet Flags:
+ *
+ * This flag indicates that the server should send back a completion for this
+ * packet.
+ */
+
+#define REQUEST_COMPLETION_FLAG	0x1
+
+/* Matches Windows-end */
+enum storvsc_request_type {
+	WRITE_TYPE = 0,
+	READ_TYPE,
+	UNKNOWN_TYPE,
+};
+
+/*
+ * SRB status codes and masks; a subset of the codes used here.
+ */
+
+#define SRB_STATUS_AUTOSENSE_VALID	0x80
+#define SRB_STATUS_INVALID_LUN	0x20
+#define SRB_STATUS_SUCCESS	0x01
+#define SRB_STATUS_ERROR	0x04
+
+/*
+ * This is the end of Protocol specific defines.
+ */
+
+
+/*
+ * We setup a mempool to allocate request structures for this driver
+ * on a per-lun basis. The following define specifies the number of
+ * elements in the pool.
+ */
+
+#define STORVSC_MIN_BUF_NR				64
+static int storvsc_ringbuffer_size = (20 * PAGE_SIZE);
+
+module_param(storvsc_ringbuffer_size, int, S_IRUGO);
+MODULE_PARM_DESC(storvsc_ringbuffer_size, "Ring buffer size (bytes)");
+
+#define STORVSC_MAX_IO_REQUESTS				128
+
+/*
+ * In Hyper-V, each port/path/target maps to 1 scsi host adapter.  In
+ * reality, the path/target is not used (ie always set to 0) so our
+ * scsi host adapter essentially has 1 bus with 1 target that contains
+ * up to 256 luns.
+ */
+#define STORVSC_MAX_LUNS_PER_TARGET			64
+#define STORVSC_MAX_TARGETS				1
+#define STORVSC_MAX_CHANNELS				1
+
+
+
+struct storvsc_cmd_request {
+	struct list_head entry;
+	struct scsi_cmnd *cmd;
+
+	unsigned int bounce_sgl_count;
+	struct scatterlist *bounce_sgl;
+
+	struct hv_device *device;
+
+	/* Synchronize the request/response if needed */
+	struct completion wait_event;
+
+	unsigned char *sense_buffer;
+	struct hv_multipage_buffer data_buffer;
+	struct vstor_packet vstor_packet;
+};
+
+
+/* A storvsc device is a device object that contains a vmbus channel */
+struct storvsc_device {
+	struct hv_device *device;
+
+	bool	 destroy;
+	bool	 drain_notify;
+	atomic_t num_outstanding_req;
+	struct Scsi_Host *host;
+
+	wait_queue_head_t waiting_to_drain;
+
+	/*
+	 * Each unique Port/Path/Target represents 1 channel ie scsi
+	 * controller. In reality, the pathid, targetid is always 0
+	 * and the port is set by us
+	 */
+	unsigned int port_number;
+	unsigned char path_id;
+	unsigned char target_id;
+
+	/* Used for vsc/vsp channel reset process */
+	struct storvsc_cmd_request init_request;
+	struct storvsc_cmd_request reset_request;
+};
+
+struct stor_mem_pools {
+	struct kmem_cache *request_pool;
+	mempool_t *request_mempool;
+};
+
+struct hv_host_device {
+	struct hv_device *dev;
+	unsigned int port;
+	unsigned char path;
+	unsigned char target;
+};
+
+struct storvsc_scan_work {
+	struct work_struct work;
+	struct Scsi_Host *host;
+	uint lun;
+};
+
+static void storvsc_bus_scan(struct work_struct *work)
+{
+	struct storvsc_scan_work *wrk;
+	int id, order_id;
+
+	wrk = container_of(work, struct storvsc_scan_work, work);
+	for (id = 0; id < wrk->host->max_id; ++id) {
+		if (wrk->host->reverse_ordering)
+			order_id = wrk->host->max_id - id - 1;
+		else
+			order_id = id;
+
+		scsi_scan_target(&wrk->host->shost_gendev, 0,
+				order_id, SCAN_WILD_CARD, 1);
+	}
+	kfree(wrk);
+}
+
+static void storvsc_remove_lun(struct work_struct *work)
+{
+	struct storvsc_scan_work *wrk;
+	struct scsi_device *sdev;
+
+	wrk = container_of(work, struct storvsc_scan_work, work);
+	if (!scsi_host_get(wrk->host))
+		goto done;
+
+	sdev = scsi_device_lookup(wrk->host, 0, 0, wrk->lun);
+
+	if (sdev) {
+		scsi_remove_device(sdev);
+		scsi_device_put(sdev);
+	}
+	scsi_host_put(wrk->host);
+
+done:
+	kfree(wrk);
+}
+
+/*
+ * Major/minor macros.  Minor version is in LSB, meaning that earlier flat
+ * version numbers will be interpreted as "0.x" (i.e., 1 becomes 0.1).
+ */
+
+static inline u16 storvsc_get_version(u8 major, u8 minor)
+{
+	u16 version;
+
+	version = ((major << 8) | minor);
+	return version;
+}
+
+/*
+ * We can get incoming messages from the host that are not in response to
+ * messages that we have sent out. An example of this would be messages
+ * received by the guest to notify dynamic addition/removal of LUNs. To
+ * deal with potential race conditions where the driver may be in the
+ * midst of being unloaded when we might receive an unsolicited message
+ * from the host, we have implemented a mechanism to gurantee sequential
+ * consistency:
+ *
+ * 1) Once the device is marked as being destroyed, we will fail all
+ *    outgoing messages.
+ * 2) We permit incoming messages when the device is being destroyed,
+ *    only to properly account for messages already sent out.
+ */
+
+static inline struct storvsc_device *get_out_stor_device(
+					struct hv_device *device)
+{
+	struct storvsc_device *stor_device;
+
+	stor_device = hv_get_drvdata(device);
+
+	if (stor_device && stor_device->destroy)
+		stor_device = NULL;
+
+	return stor_device;
+}
+
+
+static inline void storvsc_wait_to_drain(struct storvsc_device *dev)
+{
+	dev->drain_notify = true;
+	wait_event(dev->waiting_to_drain,
+		   atomic_read(&dev->num_outstanding_req) == 0);
+	dev->drain_notify = false;
+}
+
+static inline struct storvsc_device *get_in_stor_device(
+					struct hv_device *device)
+{
+	struct storvsc_device *stor_device;
+
+	stor_device = hv_get_drvdata(device);
+
+	if (!stor_device)
+		goto get_in_err;
+
+	/*
+	 * If the device is being destroyed; allow incoming
+	 * traffic only to cleanup outstanding requests.
+	 */
+
+	if (stor_device->destroy  &&
+		(atomic_read(&stor_device->num_outstanding_req) == 0))
+		stor_device = NULL;
+
+get_in_err:
+	return stor_device;
+
+}
+
+static void destroy_bounce_buffer(struct scatterlist *sgl,
+				  unsigned int sg_count)
+{
+	int i;
+	struct page *page_buf;
+
+	for (i = 0; i < sg_count; i++) {
+		page_buf = sg_page((&sgl[i]));
+		if (page_buf != NULL)
+			__free_page(page_buf);
+	}
+
+	kfree(sgl);
+}
+
+static int do_bounce_buffer(struct scatterlist *sgl, unsigned int sg_count)
+{
+	int i;
+
+	/* No need to check */
+	if (sg_count < 2)
+		return -1;
+
+	/* We have at least 2 sg entries */
+	for (i = 0; i < sg_count; i++) {
+		if (i == 0) {
+			/* make sure 1st one does not have hole */
+			if (sgl[i].offset + sgl[i].length != PAGE_SIZE)
+				return i;
+		} else if (i == sg_count - 1) {
+			/* make sure last one does not have hole */
+			if (sgl[i].offset != 0)
+				return i;
+		} else {
+			/* make sure no hole in the middle */
+			if (sgl[i].length != PAGE_SIZE || sgl[i].offset != 0)
+				return i;
+		}
+	}
+	return -1;
+}
+
+static struct scatterlist *create_bounce_buffer(struct scatterlist *sgl,
+						unsigned int sg_count,
+						unsigned int len,
+						int write)
+{
+	int i;
+	int num_pages;
+	struct scatterlist *bounce_sgl;
+	struct page *page_buf;
+	unsigned int buf_len = ((write == WRITE_TYPE) ? 0 : PAGE_SIZE);
+
+	num_pages = ALIGN(len, PAGE_SIZE) >> PAGE_SHIFT;
+
+	bounce_sgl = kcalloc(num_pages, sizeof(struct scatterlist), GFP_ATOMIC);
+	if (!bounce_sgl)
+		return NULL;
+
+	for (i = 0; i < num_pages; i++) {
+		page_buf = alloc_page(GFP_ATOMIC);
+		if (!page_buf)
+			goto cleanup;
+		sg_set_page(&bounce_sgl[i], page_buf, buf_len, 0);
+	}
+
+	return bounce_sgl;
+
+cleanup:
+	destroy_bounce_buffer(bounce_sgl, num_pages);
+	return NULL;
+}
+
+/* Assume the original sgl has enough room */
+static unsigned int copy_from_bounce_buffer(struct scatterlist *orig_sgl,
+					    struct scatterlist *bounce_sgl,
+					    unsigned int orig_sgl_count,
+					    unsigned int bounce_sgl_count)
+{
+	int i;
+	int j = 0;
+	unsigned long src, dest;
+	unsigned int srclen, destlen, copylen;
+	unsigned int total_copied = 0;
+	unsigned long bounce_addr = 0;
+	unsigned long dest_addr = 0;
+	unsigned long flags;
+
+	local_irq_save(flags);
+
+	for (i = 0; i < orig_sgl_count; i++) {
+		dest_addr = (unsigned long)kmap_atomic(sg_page((&orig_sgl[i])),
+					KM_IRQ0) + orig_sgl[i].offset;
+		dest = dest_addr;
+		destlen = orig_sgl[i].length;
+
+		if (bounce_addr == 0)
+			bounce_addr =
+			(unsigned long)kmap_atomic(sg_page((&bounce_sgl[j])),
+							KM_IRQ0);
+
+		while (destlen) {
+			src = bounce_addr + bounce_sgl[j].offset;
+			srclen = bounce_sgl[j].length - bounce_sgl[j].offset;
+
+			copylen = min(srclen, destlen);
+			memcpy((void *)dest, (void *)src, copylen);
+
+			total_copied += copylen;
+			bounce_sgl[j].offset += copylen;
+			destlen -= copylen;
+			dest += copylen;
+
+			if (bounce_sgl[j].offset == bounce_sgl[j].length) {
+				/* full */
+				kunmap_atomic((void *)bounce_addr, KM_IRQ0);
+				j++;
+
+				/*
+				 * It is possible that the number of elements
+				 * in the bounce buffer may not be equal to
+				 * the number of elements in the original
+				 * scatter list. Handle this correctly.
+				 */
+
+				if (j == bounce_sgl_count) {
+					/*
+					 * We are done; cleanup and return.
+					 */
+					kunmap_atomic((void *)(dest_addr -
+							orig_sgl[i].offset),
+							KM_IRQ0);
+					local_irq_restore(flags);
+					return total_copied;
+				}
+
+				/* if we need to use another bounce buffer */
+				if (destlen || i != orig_sgl_count - 1)
+					bounce_addr =
+					(unsigned long)kmap_atomic(
+					sg_page((&bounce_sgl[j])), KM_IRQ0);
+			} else if (destlen == 0 && i == orig_sgl_count - 1) {
+				/* unmap the last bounce that is < PAGE_SIZE */
+				kunmap_atomic((void *)bounce_addr, KM_IRQ0);
+			}
+		}
+
+		kunmap_atomic((void *)(dest_addr - orig_sgl[i].offset),
+			      KM_IRQ0);
+	}
+
+	local_irq_restore(flags);
+
+	return total_copied;
+}
+
+/* Assume the bounce_sgl has enough room ie using the create_bounce_buffer() */
+static unsigned int copy_to_bounce_buffer(struct scatterlist *orig_sgl,
+					  struct scatterlist *bounce_sgl,
+					  unsigned int orig_sgl_count)
+{
+	int i;
+	int j = 0;
+	unsigned long src, dest;
+	unsigned int srclen, destlen, copylen;
+	unsigned int total_copied = 0;
+	unsigned long bounce_addr = 0;
+	unsigned long src_addr = 0;
+	unsigned long flags;
+
+	local_irq_save(flags);
+
+	for (i = 0; i < orig_sgl_count; i++) {
+		src_addr = (unsigned long)kmap_atomic(sg_page((&orig_sgl[i])),
+				KM_IRQ0) + orig_sgl[i].offset;
+		src = src_addr;
+		srclen = orig_sgl[i].length;
+
+		if (bounce_addr == 0)
+			bounce_addr =
+			(unsigned long)kmap_atomic(sg_page((&bounce_sgl[j])),
+						KM_IRQ0);
+
+		while (srclen) {
+			/* assume bounce offset always == 0 */
+			dest = bounce_addr + bounce_sgl[j].length;
+			destlen = PAGE_SIZE - bounce_sgl[j].length;
+
+			copylen = min(srclen, destlen);
+			memcpy((void *)dest, (void *)src, copylen);
+
+			total_copied += copylen;
+			bounce_sgl[j].length += copylen;
+			srclen -= copylen;
+			src += copylen;
+
+			if (bounce_sgl[j].length == PAGE_SIZE) {
+				/* full..move to next entry */
+				kunmap_atomic((void *)bounce_addr, KM_IRQ0);
+				j++;
+
+				/* if we need to use another bounce buffer */
+				if (srclen || i != orig_sgl_count - 1)
+					bounce_addr =
+					(unsigned long)kmap_atomic(
+					sg_page((&bounce_sgl[j])), KM_IRQ0);
+
+			} else if (srclen == 0 && i == orig_sgl_count - 1) {
+				/* unmap the last bounce that is < PAGE_SIZE */
+				kunmap_atomic((void *)bounce_addr, KM_IRQ0);
+			}
+		}
+
+		kunmap_atomic((void *)(src_addr - orig_sgl[i].offset), KM_IRQ0);
+	}
+
+	local_irq_restore(flags);
+
+	return total_copied;
+}
+
+static int storvsc_channel_init(struct hv_device *device)
+{
+	struct storvsc_device *stor_device;
+	struct storvsc_cmd_request *request;
+	struct vstor_packet *vstor_packet;
+	int ret, t;
+
+	stor_device = get_out_stor_device(device);
+	if (!stor_device)
+		return -ENODEV;
+
+	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 storvsc_cmd_request));
+	init_completion(&request->wait_event);
+	vstor_packet->operation = VSTOR_OPERATION_BEGIN_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;
+
+
+	/* 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 =
+		storvsc_get_version(VMSTOR_CURRENT_MAJOR, VMSTOR_CURRENT_MINOR);
+
+	/*
+	 * The revision number is only used in Windows; set it to 0.
+	 */
+	vstor_packet->version.revision = 0;
+
+	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;
+
+
+	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;
+	}
+
+	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;
+
+	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;
+
+
+cleanup:
+	return ret;
+}
+
+
+static void storvsc_command_completion(struct storvsc_cmd_request *cmd_request)
+{
+	struct scsi_cmnd *scmnd = cmd_request->cmd;
+	struct hv_host_device *host_dev = shost_priv(scmnd->device->host);
+	void (*scsi_done_fn)(struct scsi_cmnd *);
+	struct scsi_sense_hdr sense_hdr;
+	struct vmscsi_request *vm_srb;
+	struct storvsc_scan_work *wrk;
+	struct stor_mem_pools *memp = scmnd->device->hostdata;
+
+	vm_srb = &cmd_request->vstor_packet.vm_srb;
+	if (cmd_request->bounce_sgl_count) {
+		if (vm_srb->data_in == READ_TYPE)
+			copy_from_bounce_buffer(scsi_sglist(scmnd),
+					cmd_request->bounce_sgl,
+					scsi_sg_count(scmnd),
+					cmd_request->bounce_sgl_count);
+		destroy_bounce_buffer(cmd_request->bounce_sgl,
+					cmd_request->bounce_sgl_count);
+	}
+
+	/*
+	 * If there is an error; offline the device since all
+	 * error recovery strategies would have already been
+	 * deployed on the host side.
+	 */
+	if (vm_srb->srb_status == SRB_STATUS_ERROR)
+		scmnd->result = DID_TARGET_FAILURE << 16;
+	else
+		scmnd->result = vm_srb->scsi_status;
+
+	/*
+	 * If the LUN is invalid; remove the device.
+	 */
+	if (vm_srb->srb_status == SRB_STATUS_INVALID_LUN) {
+		struct storvsc_device *stor_dev;
+		struct hv_device *dev = host_dev->dev;
+		struct Scsi_Host *host;
+
+		stor_dev = get_in_stor_device(dev);
+		host = stor_dev->host;
+
+		wrk = kmalloc(sizeof(struct storvsc_scan_work),
+				GFP_ATOMIC);
+		if (!wrk) {
+			scmnd->result = DID_TARGET_FAILURE << 16;
+		} else {
+			wrk->host = host;
+			wrk->lun = vm_srb->lun;
+			INIT_WORK(&wrk->work, storvsc_remove_lun);
+			schedule_work(&wrk->work);
+		}
+	}
+
+	if (scmnd->result) {
+		if (scsi_normalize_sense(scmnd->sense_buffer,
+				SCSI_SENSE_BUFFERSIZE, &sense_hdr))
+			scsi_print_sense_hdr("storvsc", &sense_hdr);
+	}
+
+	scsi_set_resid(scmnd,
+		cmd_request->data_buffer.len -
+		vm_srb->data_transfer_length);
+
+	scsi_done_fn = scmnd->scsi_done;
+
+	scmnd->host_scribble = NULL;
+	scmnd->scsi_done = NULL;
+
+	scsi_done_fn(scmnd);
+
+	mempool_free(cmd_request, memp->request_mempool);
+}
+
+static void storvsc_on_io_completion(struct hv_device *device,
+				  struct vstor_packet *vstor_packet,
+				  struct storvsc_cmd_request *request)
+{
+	struct storvsc_device *stor_device;
+	struct vstor_packet *stor_pkt;
+
+	stor_device = hv_get_drvdata(device);
+	stor_pkt = &request->vstor_packet;
+
+	/*
+	 * The current SCSI handling on the host side does
+	 * not correctly handle:
+	 * INQUIRY command with page code parameter set to 0x80
+	 * MODE_SENSE command with cmd[2] == 0x1c
+	 *
+	 * Setup srb and scsi status so this won't be fatal.
+	 * We do this so we can distinguish truly fatal failues
+	 * (srb status == 0x4) and off-line the device in that case.
+	 */
+
+	if ((stor_pkt->vm_srb.cdb[0] == INQUIRY) ||
+	   (stor_pkt->vm_srb.cdb[0] == MODE_SENSE)) {
+		vstor_packet->vm_srb.scsi_status = 0;
+		vstor_packet->vm_srb.srb_status = SRB_STATUS_SUCCESS;
+	}
+
+
+	/* 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 != SRB_STATUS_SUCCESS){
+		dev_warn(&device->device,
+			 "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 &
+			SRB_STATUS_AUTOSENSE_VALID) {
+			/* autosense data available */
+			dev_warn(&device->device,
+				 "stor 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;
+
+	storvsc_command_completion(request);
+
+	if (atomic_dec_and_test(&stor_device->num_outstanding_req) &&
+		stor_device->drain_notify)
+		wake_up(&stor_device->waiting_to_drain);
+
+
+}
+
+static void storvsc_on_receive(struct hv_device *device,
+			     struct vstor_packet *vstor_packet,
+			     struct storvsc_cmd_request *request)
+{
+	struct storvsc_scan_work *work;
+	struct storvsc_device *stor_device;
+
+	switch (vstor_packet->operation) {
+	case VSTOR_OPERATION_COMPLETE_IO:
+		storvsc_on_io_completion(device, vstor_packet, request);
+		break;
+
+	case VSTOR_OPERATION_REMOVE_DEVICE:
+	case VSTOR_OPERATION_ENUMERATE_BUS:
+		stor_device = get_in_stor_device(device);
+		work = kmalloc(sizeof(struct storvsc_scan_work), GFP_ATOMIC);
+		if (!work)
+			return;
+
+		INIT_WORK(&work->work, storvsc_bus_scan);
+		work->host = stor_device->host;
+		schedule_work(&work->work);
+		break;
+
+	default:
+		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 storvsc_cmd_request *request;
+	int ret;
+
+
+	stor_device = get_in_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 storvsc_cmd_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);
+
+	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));
+
+	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 ret;
+
+	ret = storvsc_channel_init(device);
+
+	return ret;
+}
+
+static int storvsc_dev_remove(struct hv_device *device)
+{
+	struct storvsc_device *stor_device;
+	unsigned long flags;
+
+	stor_device = hv_get_drvdata(device);
+
+	spin_lock_irqsave(&device->channel->inbound_lock, flags);
+	stor_device->destroy = true;
+	spin_unlock_irqrestore(&device->channel->inbound_lock, flags);
+
+	/*
+	 * 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);
+
+	/*
+	 * Since we have already drained, we don't need to busy wait
+	 * as was done in final_release_stor_device()
+	 * Note that we cannot set the ext pointer to NULL until
+	 * we have drained - to drain the outgoing packets, we need to
+	 * allow incoming packets.
+	 */
+	spin_lock_irqsave(&device->channel->inbound_lock, flags);
+	hv_set_drvdata(device, NULL);
+	spin_unlock_irqrestore(&device->channel->inbound_lock, flags);
+
+	/* Close the channel */
+	vmbus_close(device->channel);
+
+	kfree(stor_device);
+	return 0;
+}
+
+static int storvsc_do_io(struct hv_device *device,
+			      struct storvsc_cmd_request *request)
+{
+	struct storvsc_device *stor_device;
+	struct vstor_packet *vstor_packet;
+	int ret = 0;
+
+	vstor_packet = &request->vstor_packet;
+	stor_device = get_out_stor_device(device);
+
+	if (!stor_device)
+		return -ENODEV;
+
+
+	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 = STORVSC_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);
+
+	return ret;
+}
+
+static int storvsc_device_alloc(struct scsi_device *sdevice)
+{
+	struct stor_mem_pools *memp;
+	int number = STORVSC_MIN_BUF_NR;
+
+	memp = kzalloc(sizeof(struct stor_mem_pools), GFP_KERNEL);
+	if (!memp)
+		return -ENOMEM;
+
+	memp->request_pool =
+		kmem_cache_create(dev_name(&sdevice->sdev_dev),
+				sizeof(struct storvsc_cmd_request), 0,
+				SLAB_HWCACHE_ALIGN, NULL);
+
+	if (!memp->request_pool)
+		goto err0;
+
+	memp->request_mempool = mempool_create(number, mempool_alloc_slab,
+						mempool_free_slab,
+						memp->request_pool);
+
+	if (!memp->request_mempool)
+		goto err1;
+
+	sdevice->hostdata = memp;
+
+	return 0;
+
+err1:
+	kmem_cache_destroy(memp->request_pool);
+
+err0:
+	kfree(memp);
+	return -ENOMEM;
+}
+
+static void storvsc_device_destroy(struct scsi_device *sdevice)
+{
+	struct stor_mem_pools *memp = sdevice->hostdata;
+
+	mempool_destroy(memp->request_mempool);
+	kmem_cache_destroy(memp->request_pool);
+	kfree(memp);
+	sdevice->hostdata = NULL;
+}
+
+static int storvsc_device_configure(struct scsi_device *sdevice)
+{
+	scsi_adjust_queue_depth(sdevice, MSG_SIMPLE_TAG,
+				STORVSC_MAX_IO_REQUESTS);
+
+	blk_queue_max_segment_size(sdevice->request_queue, PAGE_SIZE);
+
+	blk_queue_bounce_limit(sdevice->request_queue, BLK_BOUNCE_ANY);
+
+	return 0;
+}
+
+static int storvsc_get_chs(struct scsi_device *sdev, struct block_device * bdev,
+			   sector_t capacity, int *info)
+{
+	sector_t nsect = capacity;
+	sector_t cylinders = nsect;
+	int heads, sectors_pt;
+
+	/*
+	 * We are making up these values; let us keep it simple.
+	 */
+	heads = 0xff;
+	sectors_pt = 0x3f;      /* Sectors per track */
+	sector_div(cylinders, heads * sectors_pt);
+	if ((sector_t)(cylinders + 1) * heads * sectors_pt < nsect)
+		cylinders = 0xffff;
+
+	info[0] = heads;
+	info[1] = sectors_pt;
+	info[2] = (int)cylinders;
+
+	return 0;
+}
+
+static int storvsc_host_reset_handler(struct scsi_cmnd *scmnd)
+{
+	struct hv_host_device *host_dev = shost_priv(scmnd->device->host);
+	struct hv_device *device = host_dev->dev;
+
+	struct storvsc_device *stor_device;
+	struct storvsc_cmd_request *request;
+	struct vstor_packet *vstor_packet;
+	int ret, t;
+
+
+	stor_device = get_out_stor_device(device);
+	if (!stor_device)
+		return FAILED;
+
+	request = &stor_device->reset_request;
+	vstor_packet = &request->vstor_packet;
+
+	init_completion(&request->wait_event);
+
+	vstor_packet->operation = VSTOR_OPERATION_RESET_BUS;
+	vstor_packet->flags = REQUEST_COMPLETION_FLAG;
+	vstor_packet->vm_srb.path_id = stor_device->path_id;
+
+	ret = vmbus_sendpacket(device->channel, vstor_packet,
+			       sizeof(struct vstor_packet),
+			       (unsigned long)&stor_device->reset_request,
+			       VM_PKT_DATA_INBAND,
+			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
+	if (ret != 0)
+		return FAILED;
+
+	t = wait_for_completion_timeout(&request->wait_event, 5*HZ);
+	if (t == 0)
+		return TIMEOUT_ERROR;
+
+
+	/*
+	 * At this point, all outstanding requests in the adapter
+	 * should have been flushed out and return to us
+	 */
+
+	return SUCCESS;
+}
+
+static bool storvsc_scsi_cmd_ok(struct scsi_cmnd *scmnd)
+{
+	bool allowed = true;
+	u8 scsi_op = scmnd->cmnd[0];
+
+	switch (scsi_op) {
+	/*
+	 * smartd sends this command and the host does not handle
+	 * this. So, don't send it.
+	 */
+	case SET_WINDOW:
+		scmnd->result = ILLEGAL_REQUEST << 16;
+		allowed = false;
+		break;
+	default:
+		break;
+	}
+	return allowed;
+}
+
+static int storvsc_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *scmnd)
+{
+	int ret;
+	struct hv_host_device *host_dev = shost_priv(host);
+	struct hv_device *dev = host_dev->dev;
+	struct storvsc_cmd_request *cmd_request;
+	unsigned int request_size = 0;
+	int i;
+	struct scatterlist *sgl;
+	unsigned int sg_count = 0;
+	struct vmscsi_request *vm_srb;
+	struct stor_mem_pools *memp = scmnd->device->hostdata;
+
+	if (!storvsc_scsi_cmd_ok(scmnd)) {
+		scmnd->scsi_done(scmnd);
+		return 0;
+	}
+
+	request_size = sizeof(struct storvsc_cmd_request);
+
+	cmd_request = mempool_alloc(memp->request_mempool,
+				       GFP_ATOMIC);
+
+	/*
+	 * We might be invoked in an interrupt context; hence
+	 * mempool_alloc() can fail.
+	 */
+	if (!cmd_request)
+		return SCSI_MLQUEUE_DEVICE_BUSY;
+
+	memset(cmd_request, 0, sizeof(struct storvsc_cmd_request));
+
+	/* Setup the cmd request */
+	cmd_request->cmd = scmnd;
+
+	scmnd->host_scribble = (unsigned char *)cmd_request;
+
+	vm_srb = &cmd_request->vstor_packet.vm_srb;
+
+
+	/* Build the SRB */
+	switch (scmnd->sc_data_direction) {
+	case DMA_TO_DEVICE:
+		vm_srb->data_in = WRITE_TYPE;
+		break;
+	case DMA_FROM_DEVICE:
+		vm_srb->data_in = READ_TYPE;
+		break;
+	default:
+		vm_srb->data_in = UNKNOWN_TYPE;
+		break;
+	}
+
+
+	vm_srb->port_number = host_dev->port;
+	vm_srb->path_id = scmnd->device->channel;
+	vm_srb->target_id = scmnd->device->id;
+	vm_srb->lun = scmnd->device->lun;
+
+	vm_srb->cdb_length = scmnd->cmd_len;
+
+	memcpy(vm_srb->cdb, scmnd->cmnd, vm_srb->cdb_length);
+
+	cmd_request->sense_buffer = scmnd->sense_buffer;
+
+
+	cmd_request->data_buffer.len = scsi_bufflen(scmnd);
+	if (scsi_sg_count(scmnd)) {
+		sgl = (struct scatterlist *)scsi_sglist(scmnd);
+		sg_count = scsi_sg_count(scmnd);
+
+		/* check if we need to bounce the sgl */
+		if (do_bounce_buffer(sgl, scsi_sg_count(scmnd)) != -1) {
+			cmd_request->bounce_sgl =
+				create_bounce_buffer(sgl, scsi_sg_count(scmnd),
+						     scsi_bufflen(scmnd),
+						     vm_srb->data_in);
+			if (!cmd_request->bounce_sgl) {
+				ret = SCSI_MLQUEUE_HOST_BUSY;
+				goto queue_error;
+			}
+
+			cmd_request->bounce_sgl_count =
+				ALIGN(scsi_bufflen(scmnd), PAGE_SIZE) >>
+					PAGE_SHIFT;
+
+			if (vm_srb->data_in == WRITE_TYPE)
+				copy_to_bounce_buffer(sgl,
+					cmd_request->bounce_sgl,
+					scsi_sg_count(scmnd));
+
+			sgl = cmd_request->bounce_sgl;
+			sg_count = cmd_request->bounce_sgl_count;
+		}
+
+		cmd_request->data_buffer.offset = sgl[0].offset;
+
+		for (i = 0; i < sg_count; i++)
+			cmd_request->data_buffer.pfn_array[i] =
+				page_to_pfn(sg_page((&sgl[i])));
+
+	} else if (scsi_sglist(scmnd)) {
+		cmd_request->data_buffer.offset =
+			virt_to_phys(scsi_sglist(scmnd)) & (PAGE_SIZE-1);
+		cmd_request->data_buffer.pfn_array[0] =
+			virt_to_phys(scsi_sglist(scmnd)) >> PAGE_SHIFT;
+	}
+
+	/* Invokes the vsc to start an IO */
+	ret = storvsc_do_io(dev, cmd_request);
+
+	if (ret == -EAGAIN) {
+		/* no more space */
+
+		if (cmd_request->bounce_sgl_count) {
+			destroy_bounce_buffer(cmd_request->bounce_sgl,
+					cmd_request->bounce_sgl_count);
+
+			ret = SCSI_MLQUEUE_DEVICE_BUSY;
+			goto queue_error;
+		}
+	}
+
+	return 0;
+
+queue_error:
+	mempool_free(cmd_request, memp->request_mempool);
+	scmnd->host_scribble = NULL;
+	return ret;
+}
+
+static struct scsi_host_template scsi_driver = {
+	.module	=		THIS_MODULE,
+	.name =			"storvsc_host_t",
+	.bios_param =		storvsc_get_chs,
+	.queuecommand =		storvsc_queuecommand,
+	.eh_host_reset_handler =	storvsc_host_reset_handler,
+	.slave_alloc =		storvsc_device_alloc,
+	.slave_destroy =	storvsc_device_destroy,
+	.slave_configure =	storvsc_device_configure,
+	.cmd_per_lun =		1,
+	/* 64 max_queue * 1 target */
+	.can_queue =		STORVSC_MAX_IO_REQUESTS*STORVSC_MAX_TARGETS,
+	.this_id =		-1,
+	/* no use setting to 0 since ll_blk_rw reset it to 1 */
+	/* currently 32 */
+	.sg_tablesize =		MAX_MULTIPAGE_BUFFER_COUNT,
+	.use_clustering =	DISABLE_CLUSTERING,
+	/* Make sure we dont get a sg segment crosses a page boundary */
+	.dma_boundary =		PAGE_SIZE-1,
+};
+
+enum {
+	SCSI_GUID,
+	IDE_GUID,
+};
+
+static const struct hv_vmbus_device_id id_table[] = {
+	/* SCSI guid */
+	{ VMBUS_DEVICE(0xd9, 0x63, 0x61, 0xba, 0xa1, 0x04, 0x29, 0x4d,
+		       0xb6, 0x05, 0x72, 0xe2, 0xff, 0xb1, 0xdc, 0x7f)
+	  .driver_data = SCSI_GUID },
+	/* IDE guid */
+	{ VMBUS_DEVICE(0x32, 0x26, 0x41, 0x32, 0xcb, 0x86, 0xa2, 0x44,
+		       0x9b, 0x5c, 0x50, 0xd1, 0x41, 0x73, 0x54, 0xf5)
+	  .driver_data = IDE_GUID },
+	{ },
+};
+
+MODULE_DEVICE_TABLE(vmbus, id_table);
+
+static int storvsc_probe(struct hv_device *device,
+			const struct hv_vmbus_device_id *dev_id)
+{
+	int ret;
+	struct Scsi_Host *host;
+	struct hv_host_device *host_dev;
+	bool dev_is_ide = ((dev_id->driver_data == IDE_GUID) ? true : false);
+	int target = 0;
+	struct storvsc_device *stor_device;
+
+	host = scsi_host_alloc(&scsi_driver,
+			       sizeof(struct hv_host_device));
+	if (!host)
+		return -ENOMEM;
+
+	host_dev = shost_priv(host);
+	memset(host_dev, 0, sizeof(struct hv_host_device));
+
+	host_dev->port = host->host_no;
+	host_dev->dev = device;
+
+
+	stor_device = kzalloc(sizeof(struct storvsc_device), GFP_KERNEL);
+	if (!stor_device) {
+		ret = -ENOMEM;
+		goto err_out0;
+	}
+
+	stor_device->destroy = false;
+	init_waitqueue_head(&stor_device->waiting_to_drain);
+	stor_device->device = device;
+	stor_device->host = host;
+	hv_set_drvdata(device, stor_device);
+
+	stor_device->port_number = host->host_no;
+	ret = storvsc_connect_to_vsp(device, storvsc_ringbuffer_size);
+	if (ret)
+		goto err_out1;
+
+	host_dev->path = stor_device->path_id;
+	host_dev->target = stor_device->target_id;
+
+	/* max # of devices per target */
+	host->max_lun = STORVSC_MAX_LUNS_PER_TARGET;
+	/* max # of targets per channel */
+	host->max_id = STORVSC_MAX_TARGETS;
+	/* max # of channels */
+	host->max_channel = STORVSC_MAX_CHANNELS - 1;
+	/* max cmd length */
+	host->max_cmd_len = STORVSC_MAX_CMD_LEN;
+
+	/* Register the HBA and start the scsi bus scan */
+	ret = scsi_add_host(host, &device->device);
+	if (ret != 0)
+		goto err_out2;
+
+	if (!dev_is_ide) {
+		scsi_scan_host(host);
+	} else {
+		target = (device->dev_instance.b[5] << 8 |
+			 device->dev_instance.b[4]);
+		ret = scsi_add_device(host, 0, target, 0);
+		if (ret) {
+			scsi_remove_host(host);
+			goto err_out2;
+		}
+	}
+	return 0;
+
+err_out2:
+	/*
+	 * Once we have connected with the host, we would need to
+	 * to invoke storvsc_dev_remove() to rollback this state and
+	 * this call also frees up the stor_device; hence the jump around
+	 * err_out1 label.
+	 */
+	storvsc_dev_remove(device);
+	goto err_out0;
+
+err_out1:
+	kfree(stor_device);
+
+err_out0:
+	scsi_host_put(host);
+	return ret;
+}
+
+static int storvsc_remove(struct hv_device *dev)
+{
+	struct storvsc_device *stor_device = hv_get_drvdata(dev);
+	struct Scsi_Host *host = stor_device->host;
+
+	scsi_remove_host(host);
+	storvsc_dev_remove(dev);
+	scsi_host_put(host);
+
+	return 0;
+}
+
+static struct hv_driver storvsc_drv = {
+	.name = KBUILD_MODNAME,
+	.id_table = id_table,
+	.probe = storvsc_probe,
+	.remove = storvsc_remove,
+};
+
+static int __init storvsc_drv_init(void)
+{
+	u32 max_outstanding_req_per_channel;
+
+	/*
+	 * Divide the ring buffer data size (which is 1 page less
+	 * than the ring buffer size since that page is reserved for
+	 * the ring buffer indices) by the max request size (which is
+	 * vmbus_channel_packet_multipage_buffer + struct vstor_packet + u64)
+	 */
+	max_outstanding_req_per_channel =
+		((storvsc_ringbuffer_size - PAGE_SIZE) /
+		ALIGN(MAX_MULTIPAGE_BUFFER_PACKET +
+		sizeof(struct vstor_packet) + sizeof(u64),
+		sizeof(u64)));
+
+	if (max_outstanding_req_per_channel <
+	    STORVSC_MAX_IO_REQUESTS)
+		return -EINVAL;
+
+	return vmbus_driver_register(&storvsc_drv);
+}
+
+static void __exit storvsc_drv_exit(void)
+{
+	vmbus_driver_unregister(&storvsc_drv);
+}
+
+MODULE_LICENSE("GPL");
+MODULE_VERSION(HV_DRV_VERSION);
+MODULE_DESCRIPTION("Microsoft Hyper-V virtual storage driver");
+module_init(storvsc_drv_init);
+module_exit(storvsc_drv_exit);