storvsc: Untangle the storage protocol negotiation from the vmbus protocol negotiation.

Currently we are making decisions based on vmbus protocol versions
that have been negotiated; use storage potocol versions instead.

[jejb: fold ARRAY_SIZE conversion suggested by Johannes Thumshirn
<jthumshirn@suse.de>
make vmstor_protocol static]
Tested-by: Alex Ng <alexng@microsoft.com>
Signed-off-by: Keith Mange <keith.mange@microsoft.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: James Bottomley <JBottomley@Odin.com>

drivers/scsi/storvsc_drv.c

@@ -56,14 +56,18 @@
  * V1 RC > 2008/1/31:  2.0
  * Win7: 4.2
  * Win8: 5.1
+ * Win8.1: 6.0
+ * Win10: 6.2
  */
 
 #define VMSTOR_PROTO_VERSION(MAJOR_, MINOR_)	((((MAJOR_) & 0xff) << 8) | \
 						(((MINOR_) & 0xff)))
 
+#define VMSTOR_PROTO_VERSION_WIN6	VMSTOR_PROTO_VERSION(2, 0)
 #define VMSTOR_PROTO_VERSION_WIN7	VMSTOR_PROTO_VERSION(4, 2)
 #define VMSTOR_PROTO_VERSION_WIN8	VMSTOR_PROTO_VERSION(5, 1)
-
+#define VMSTOR_PROTO_VERSION_WIN8_1	VMSTOR_PROTO_VERSION(6, 0)
+#define VMSTOR_PROTO_VERSION_WIN10	VMSTOR_PROTO_VERSION(6, 2)
 
 /*  Packet structure describing virtual storage requests. */
 enum vstor_packet_operation {
@@ -204,6 +208,45 @@ struct vmscsi_request {
 } __attribute((packed));
 
 
+/*
+ * The list of storage protocols in order of preference.
+ */
+struct vmstor_protocol {
+	int protocol_version;
+	int sense_buffer_size;
+	int vmscsi_size_delta;
+};
+
+
+static const struct vmstor_protocol vmstor_protocols[] = {
+	{
+		VMSTOR_PROTO_VERSION_WIN10,
+		POST_WIN7_STORVSC_SENSE_BUFFER_SIZE,
+		0
+	},
+	{
+		VMSTOR_PROTO_VERSION_WIN8_1,
+		POST_WIN7_STORVSC_SENSE_BUFFER_SIZE,
+		0
+	},
+	{
+		VMSTOR_PROTO_VERSION_WIN8,
+		POST_WIN7_STORVSC_SENSE_BUFFER_SIZE,
+		0
+	},
+	{
+		VMSTOR_PROTO_VERSION_WIN7,
+		PRE_WIN8_STORVSC_SENSE_BUFFER_SIZE,
+		sizeof(struct vmscsi_win8_extension),
+	},
+	{
+		VMSTOR_PROTO_VERSION_WIN6,
+		PRE_WIN8_STORVSC_SENSE_BUFFER_SIZE,
+		sizeof(struct vmscsi_win8_extension),
+	}
+};
+
+
 /*
  * This structure is sent during the intialization phase to get the different
  * properties of the channel.
@@ -864,7 +907,7 @@ 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;
+	int ret, t, i;
 	int max_chns;
 	bool process_sub_channels = false;
 
@@ -904,12 +947,15 @@ static int storvsc_channel_init(struct hv_device *device)
 		goto cleanup;
 
 
+	for (i = 0; i < ARRAY_SIZE(vmstor_protocols); i++) {
 		/* 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->operation =
+			VSTOR_OPERATION_QUERY_PROTOCOL_VERSION;
 		vstor_packet->flags = REQUEST_COMPLETION_FLAG;
 
-	vstor_packet->version.major_minor = vmstor_proto_version;
+		vstor_packet->version.major_minor =
+			vmstor_protocols[i].protocol_version;
 
 		/*
 		 * The revision number is only used in Windows; set it to 0.
@@ -931,9 +977,29 @@ static int storvsc_channel_init(struct hv_device *device)
 			goto cleanup;
 		}
 
-	if (vstor_packet->operation != VSTOR_OPERATION_COMPLETE_IO ||
-	    vstor_packet->status != 0)
+		if (vstor_packet->operation != VSTOR_OPERATION_COMPLETE_IO) {
+			ret = -EINVAL;
+			goto cleanup;
+		}
+
+		if (vstor_packet->status == 0) {
+			vmstor_proto_version =
+				vmstor_protocols[i].protocol_version;
+
+			sense_buffer_size =
+				vmstor_protocols[i].sense_buffer_size;
+
+			vmscsi_size_delta =
+				vmstor_protocols[i].vmscsi_size_delta;
+
+			break;
+		}
+	}
+
+	if (vstor_packet->status != 0) {
+		ret = -EINVAL;
 		goto cleanup;
+	}
 
 
 	memset(vstor_packet, 0, sizeof(struct vstor_packet));
@@ -1746,14 +1812,12 @@ static int storvsc_probe(struct hv_device *device,
 	if (vmbus_proto_version < VERSION_WIN8) {
 		sense_buffer_size = PRE_WIN8_STORVSC_SENSE_BUFFER_SIZE;
 		vmscsi_size_delta = sizeof(struct vmscsi_win8_extension);
-		vmstor_proto_version = VMSTOR_PROTO_VERSION_WIN7;
 		max_luns_per_target = STORVSC_IDE_MAX_LUNS_PER_TARGET;
 		max_targets = STORVSC_IDE_MAX_TARGETS;
 		max_channels = STORVSC_IDE_MAX_CHANNELS;
 	} else {
 		sense_buffer_size = POST_WIN7_STORVSC_SENSE_BUFFER_SIZE;
 		vmscsi_size_delta = 0;
-		vmstor_proto_version = VMSTOR_PROTO_VERSION_WIN8;
 		max_luns_per_target = STORVSC_MAX_LUNS_PER_TARGET;
 		max_targets = STORVSC_MAX_TARGETS;
 		max_channels = STORVSC_MAX_CHANNELS;