Staging: hv: add the Hyper-V virtual block driver

This is the virtual block driver when running Linux on top of Hyper-V.
Signed-off-by: Hank Janssen <hjanssen@microsoft.com>
Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/staging/hv/BlkVsc.c

+/*
+ *
+ * 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:
+ *   Hank Janssen  <hjanssen@microsoft.com>
+ *
+ */
+
+
+#include "../storvsc/StorVsc.c"
+
+static const char* gBlkDriverName="blkvsc";
+
+//{32412632-86cb-44a2-9b5c-50d1417354f5}
+static const GUID gBlkVscDeviceType={
+	.Data = {0x32, 0x26, 0x41, 0x32, 0xcb, 0x86, 0xa2, 0x44, 0x9b, 0x5c, 0x50, 0xd1, 0x41, 0x73, 0x54, 0xf5}
+};
+
+// Static routines
+static int
+BlkVscOnDeviceAdd(
+	DEVICE_OBJECT	*Device,
+	void			*AdditionalInfo
+	);
+
+
+int
+BlkVscInitialize(
+	DRIVER_OBJECT *Driver
+	)
+{
+	STORVSC_DRIVER_OBJECT* storDriver = (STORVSC_DRIVER_OBJECT*)Driver;
+	int ret=0;
+
+	DPRINT_ENTER(BLKVSC);
+
+	// Make sure we are at least 2 pages since 1 page is used for control
+	ASSERT(storDriver->RingBufferSize >= (PAGE_SIZE << 1));
+
+	Driver->name = gBlkDriverName;
+	memcpy(&Driver->deviceType, &gBlkVscDeviceType, sizeof(GUID));
+
+	storDriver->RequestExtSize			= sizeof(STORVSC_REQUEST_EXTENSION);
+	// 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_MULITPAGE_BUFFER + VSTOR_PACKET + UINT64)
+	storDriver->MaxOutstandingRequestsPerChannel =
+		((storDriver->RingBufferSize - PAGE_SIZE) / ALIGN_UP(MAX_MULTIPAGE_BUFFER_PACKET + sizeof(VSTOR_PACKET) + sizeof(UINT64),sizeof(UINT64)));
+
+	DPRINT_INFO(BLKVSC, "max io outstd %u", storDriver->MaxOutstandingRequestsPerChannel);
+
+	// Setup the dispatch table
+	storDriver->Base.OnDeviceAdd		= BlkVscOnDeviceAdd;
+	storDriver->Base.OnDeviceRemove		= StorVscOnDeviceRemove;
+	storDriver->Base.OnCleanup			= StorVscOnCleanup;
+
+	storDriver->OnIORequest				= StorVscOnIORequest;
+
+	DPRINT_EXIT(BLKVSC);
+
+	return ret;
+}
+
+int
+BlkVscOnDeviceAdd(
+	DEVICE_OBJECT	*Device,
+	void			*AdditionalInfo
+	)
+{
+	int ret=0;
+	STORVSC_DEVICE_INFO *deviceInfo = (STORVSC_DEVICE_INFO*)AdditionalInfo;
+
+	DPRINT_ENTER(BLKVSC);
+
+	ret = StorVscOnDeviceAdd(Device, AdditionalInfo);
+
+	if (ret != 0)
+	{
+		DPRINT_EXIT(BLKVSC);
+
+		return ret;
+	}
+
+	// We need to use the device instance guid to set the path and target id. For IDE devices, the
+	// device instance id is formatted as <bus id> - <device id> - 8899 - 000000000000.
+	deviceInfo->PathId = Device->deviceInstance.Data[3] << 24 | Device->deviceInstance.Data[2] << 16 |
+		Device->deviceInstance.Data[1] << 8 |Device->deviceInstance.Data[0];
+
+	deviceInfo->TargetId = Device->deviceInstance.Data[5] << 8 | Device->deviceInstance.Data[4];
+
+	DPRINT_EXIT(BLKVSC);
+
+	return ret;
+}