xref: /openbmc/linux/drivers/scsi/storvsc_drv.c (revision 4da722ca)
1 /*
2  * Copyright (c) 2009, Microsoft Corporation.
3  *
4  * This program is free software; you can redistribute it and/or modify it
5  * under the terms and conditions of the GNU General Public License,
6  * version 2, as published by the Free Software Foundation.
7  *
8  * This program is distributed in the hope it will be useful, but WITHOUT
9  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
10  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
11  * more details.
12  *
13  * You should have received a copy of the GNU General Public License along with
14  * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
15  * Place - Suite 330, Boston, MA 02111-1307 USA.
16  *
17  * Authors:
18  *   Haiyang Zhang <haiyangz@microsoft.com>
19  *   Hank Janssen  <hjanssen@microsoft.com>
20  *   K. Y. Srinivasan <kys@microsoft.com>
21  */
22 
23 #include <linux/kernel.h>
24 #include <linux/wait.h>
25 #include <linux/sched.h>
26 #include <linux/completion.h>
27 #include <linux/string.h>
28 #include <linux/mm.h>
29 #include <linux/delay.h>
30 #include <linux/init.h>
31 #include <linux/slab.h>
32 #include <linux/module.h>
33 #include <linux/device.h>
34 #include <linux/hyperv.h>
35 #include <linux/blkdev.h>
36 #include <scsi/scsi.h>
37 #include <scsi/scsi_cmnd.h>
38 #include <scsi/scsi_host.h>
39 #include <scsi/scsi_device.h>
40 #include <scsi/scsi_tcq.h>
41 #include <scsi/scsi_eh.h>
42 #include <scsi/scsi_devinfo.h>
43 #include <scsi/scsi_dbg.h>
44 #include <scsi/scsi_transport_fc.h>
45 #include <scsi/scsi_transport.h>
46 
47 /*
48  * All wire protocol details (storage protocol between the guest and the host)
49  * are consolidated here.
50  *
51  * Begin protocol definitions.
52  */
53 
54 /*
55  * Version history:
56  * V1 Beta: 0.1
57  * V1 RC < 2008/1/31: 1.0
58  * V1 RC > 2008/1/31:  2.0
59  * Win7: 4.2
60  * Win8: 5.1
61  * Win8.1: 6.0
62  * Win10: 6.2
63  */
64 
65 #define VMSTOR_PROTO_VERSION(MAJOR_, MINOR_)	((((MAJOR_) & 0xff) << 8) | \
66 						(((MINOR_) & 0xff)))
67 
68 #define VMSTOR_PROTO_VERSION_WIN6	VMSTOR_PROTO_VERSION(2, 0)
69 #define VMSTOR_PROTO_VERSION_WIN7	VMSTOR_PROTO_VERSION(4, 2)
70 #define VMSTOR_PROTO_VERSION_WIN8	VMSTOR_PROTO_VERSION(5, 1)
71 #define VMSTOR_PROTO_VERSION_WIN8_1	VMSTOR_PROTO_VERSION(6, 0)
72 #define VMSTOR_PROTO_VERSION_WIN10	VMSTOR_PROTO_VERSION(6, 2)
73 
74 /*  Packet structure describing virtual storage requests. */
75 enum vstor_packet_operation {
76 	VSTOR_OPERATION_COMPLETE_IO		= 1,
77 	VSTOR_OPERATION_REMOVE_DEVICE		= 2,
78 	VSTOR_OPERATION_EXECUTE_SRB		= 3,
79 	VSTOR_OPERATION_RESET_LUN		= 4,
80 	VSTOR_OPERATION_RESET_ADAPTER		= 5,
81 	VSTOR_OPERATION_RESET_BUS		= 6,
82 	VSTOR_OPERATION_BEGIN_INITIALIZATION	= 7,
83 	VSTOR_OPERATION_END_INITIALIZATION	= 8,
84 	VSTOR_OPERATION_QUERY_PROTOCOL_VERSION	= 9,
85 	VSTOR_OPERATION_QUERY_PROPERTIES	= 10,
86 	VSTOR_OPERATION_ENUMERATE_BUS		= 11,
87 	VSTOR_OPERATION_FCHBA_DATA              = 12,
88 	VSTOR_OPERATION_CREATE_SUB_CHANNELS     = 13,
89 	VSTOR_OPERATION_MAXIMUM                 = 13
90 };
91 
92 /*
93  * WWN packet for Fibre Channel HBA
94  */
95 
96 struct hv_fc_wwn_packet {
97 	u8	primary_active;
98 	u8	reserved1[3];
99 	u8	primary_port_wwn[8];
100 	u8	primary_node_wwn[8];
101 	u8	secondary_port_wwn[8];
102 	u8	secondary_node_wwn[8];
103 };
104 
105 
106 
107 /*
108  * SRB Flag Bits
109  */
110 
111 #define SRB_FLAGS_QUEUE_ACTION_ENABLE		0x00000002
112 #define SRB_FLAGS_DISABLE_DISCONNECT		0x00000004
113 #define SRB_FLAGS_DISABLE_SYNCH_TRANSFER	0x00000008
114 #define SRB_FLAGS_BYPASS_FROZEN_QUEUE		0x00000010
115 #define SRB_FLAGS_DISABLE_AUTOSENSE		0x00000020
116 #define SRB_FLAGS_DATA_IN			0x00000040
117 #define SRB_FLAGS_DATA_OUT			0x00000080
118 #define SRB_FLAGS_NO_DATA_TRANSFER		0x00000000
119 #define SRB_FLAGS_UNSPECIFIED_DIRECTION	(SRB_FLAGS_DATA_IN | SRB_FLAGS_DATA_OUT)
120 #define SRB_FLAGS_NO_QUEUE_FREEZE		0x00000100
121 #define SRB_FLAGS_ADAPTER_CACHE_ENABLE		0x00000200
122 #define SRB_FLAGS_FREE_SENSE_BUFFER		0x00000400
123 
124 /*
125  * This flag indicates the request is part of the workflow for processing a D3.
126  */
127 #define SRB_FLAGS_D3_PROCESSING			0x00000800
128 #define SRB_FLAGS_IS_ACTIVE			0x00010000
129 #define SRB_FLAGS_ALLOCATED_FROM_ZONE		0x00020000
130 #define SRB_FLAGS_SGLIST_FROM_POOL		0x00040000
131 #define SRB_FLAGS_BYPASS_LOCKED_QUEUE		0x00080000
132 #define SRB_FLAGS_NO_KEEP_AWAKE			0x00100000
133 #define SRB_FLAGS_PORT_DRIVER_ALLOCSENSE	0x00200000
134 #define SRB_FLAGS_PORT_DRIVER_SENSEHASPORT	0x00400000
135 #define SRB_FLAGS_DONT_START_NEXT_PACKET	0x00800000
136 #define SRB_FLAGS_PORT_DRIVER_RESERVED		0x0F000000
137 #define SRB_FLAGS_CLASS_DRIVER_RESERVED		0xF0000000
138 
139 #define SP_UNTAGGED			((unsigned char) ~0)
140 #define SRB_SIMPLE_TAG_REQUEST		0x20
141 
142 /*
143  * Platform neutral description of a scsi request -
144  * this remains the same across the write regardless of 32/64 bit
145  * note: it's patterned off the SCSI_PASS_THROUGH structure
146  */
147 #define STORVSC_MAX_CMD_LEN			0x10
148 
149 #define POST_WIN7_STORVSC_SENSE_BUFFER_SIZE	0x14
150 #define PRE_WIN8_STORVSC_SENSE_BUFFER_SIZE	0x12
151 
152 #define STORVSC_SENSE_BUFFER_SIZE		0x14
153 #define STORVSC_MAX_BUF_LEN_WITH_PADDING	0x14
154 
155 /*
156  * Sense buffer size changed in win8; have a run-time
157  * variable to track the size we should use.  This value will
158  * likely change during protocol negotiation but it is valid
159  * to start by assuming pre-Win8.
160  */
161 static int sense_buffer_size = PRE_WIN8_STORVSC_SENSE_BUFFER_SIZE;
162 
163 /*
164  * The storage protocol version is determined during the
165  * initial exchange with the host.  It will indicate which
166  * storage functionality is available in the host.
167 */
168 static int vmstor_proto_version;
169 
170 #define STORVSC_LOGGING_NONE	0
171 #define STORVSC_LOGGING_ERROR	1
172 #define STORVSC_LOGGING_WARN	2
173 
174 static int logging_level = STORVSC_LOGGING_ERROR;
175 module_param(logging_level, int, S_IRUGO|S_IWUSR);
176 MODULE_PARM_DESC(logging_level,
177 	"Logging level, 0 - None, 1 - Error (default), 2 - Warning.");
178 
179 static inline bool do_logging(int level)
180 {
181 	return logging_level >= level;
182 }
183 
184 #define storvsc_log(dev, level, fmt, ...)			\
185 do {								\
186 	if (do_logging(level))					\
187 		dev_warn(&(dev)->device, fmt, ##__VA_ARGS__);	\
188 } while (0)
189 
190 struct vmscsi_win8_extension {
191 	/*
192 	 * The following were added in Windows 8
193 	 */
194 	u16 reserve;
195 	u8  queue_tag;
196 	u8  queue_action;
197 	u32 srb_flags;
198 	u32 time_out_value;
199 	u32 queue_sort_ey;
200 } __packed;
201 
202 struct vmscsi_request {
203 	u16 length;
204 	u8 srb_status;
205 	u8 scsi_status;
206 
207 	u8  port_number;
208 	u8  path_id;
209 	u8  target_id;
210 	u8  lun;
211 
212 	u8  cdb_length;
213 	u8  sense_info_length;
214 	u8  data_in;
215 	u8  reserved;
216 
217 	u32 data_transfer_length;
218 
219 	union {
220 		u8 cdb[STORVSC_MAX_CMD_LEN];
221 		u8 sense_data[STORVSC_SENSE_BUFFER_SIZE];
222 		u8 reserved_array[STORVSC_MAX_BUF_LEN_WITH_PADDING];
223 	};
224 	/*
225 	 * The following was added in win8.
226 	 */
227 	struct vmscsi_win8_extension win8_extension;
228 
229 } __attribute((packed));
230 
231 
232 /*
233  * The size of the vmscsi_request has changed in win8. The
234  * additional size is because of new elements added to the
235  * structure. These elements are valid only when we are talking
236  * to a win8 host.
237  * Track the correction to size we need to apply. This value
238  * will likely change during protocol negotiation but it is
239  * valid to start by assuming pre-Win8.
240  */
241 static int vmscsi_size_delta = sizeof(struct vmscsi_win8_extension);
242 
243 /*
244  * The list of storage protocols in order of preference.
245  */
246 struct vmstor_protocol {
247 	int protocol_version;
248 	int sense_buffer_size;
249 	int vmscsi_size_delta;
250 };
251 
252 
253 static const struct vmstor_protocol vmstor_protocols[] = {
254 	{
255 		VMSTOR_PROTO_VERSION_WIN10,
256 		POST_WIN7_STORVSC_SENSE_BUFFER_SIZE,
257 		0
258 	},
259 	{
260 		VMSTOR_PROTO_VERSION_WIN8_1,
261 		POST_WIN7_STORVSC_SENSE_BUFFER_SIZE,
262 		0
263 	},
264 	{
265 		VMSTOR_PROTO_VERSION_WIN8,
266 		POST_WIN7_STORVSC_SENSE_BUFFER_SIZE,
267 		0
268 	},
269 	{
270 		VMSTOR_PROTO_VERSION_WIN7,
271 		PRE_WIN8_STORVSC_SENSE_BUFFER_SIZE,
272 		sizeof(struct vmscsi_win8_extension),
273 	},
274 	{
275 		VMSTOR_PROTO_VERSION_WIN6,
276 		PRE_WIN8_STORVSC_SENSE_BUFFER_SIZE,
277 		sizeof(struct vmscsi_win8_extension),
278 	}
279 };
280 
281 
282 /*
283  * This structure is sent during the initialization phase to get the different
284  * properties of the channel.
285  */
286 
287 #define STORAGE_CHANNEL_SUPPORTS_MULTI_CHANNEL		0x1
288 
289 struct vmstorage_channel_properties {
290 	u32 reserved;
291 	u16 max_channel_cnt;
292 	u16 reserved1;
293 
294 	u32 flags;
295 	u32   max_transfer_bytes;
296 
297 	u64  reserved2;
298 } __packed;
299 
300 /*  This structure is sent during the storage protocol negotiations. */
301 struct vmstorage_protocol_version {
302 	/* Major (MSW) and minor (LSW) version numbers. */
303 	u16 major_minor;
304 
305 	/*
306 	 * Revision number is auto-incremented whenever this file is changed
307 	 * (See FILL_VMSTOR_REVISION macro above).  Mismatch does not
308 	 * definitely indicate incompatibility--but it does indicate mismatched
309 	 * builds.
310 	 * This is only used on the windows side. Just set it to 0.
311 	 */
312 	u16 revision;
313 } __packed;
314 
315 /* Channel Property Flags */
316 #define STORAGE_CHANNEL_REMOVABLE_FLAG		0x1
317 #define STORAGE_CHANNEL_EMULATED_IDE_FLAG	0x2
318 
319 struct vstor_packet {
320 	/* Requested operation type */
321 	enum vstor_packet_operation operation;
322 
323 	/*  Flags - see below for values */
324 	u32 flags;
325 
326 	/* Status of the request returned from the server side. */
327 	u32 status;
328 
329 	/* Data payload area */
330 	union {
331 		/*
332 		 * Structure used to forward SCSI commands from the
333 		 * client to the server.
334 		 */
335 		struct vmscsi_request vm_srb;
336 
337 		/* Structure used to query channel properties. */
338 		struct vmstorage_channel_properties storage_channel_properties;
339 
340 		/* Used during version negotiations. */
341 		struct vmstorage_protocol_version version;
342 
343 		/* Fibre channel address packet */
344 		struct hv_fc_wwn_packet wwn_packet;
345 
346 		/* Number of sub-channels to create */
347 		u16 sub_channel_count;
348 
349 		/* This will be the maximum of the union members */
350 		u8  buffer[0x34];
351 	};
352 } __packed;
353 
354 /*
355  * Packet Flags:
356  *
357  * This flag indicates that the server should send back a completion for this
358  * packet.
359  */
360 
361 #define REQUEST_COMPLETION_FLAG	0x1
362 
363 /* Matches Windows-end */
364 enum storvsc_request_type {
365 	WRITE_TYPE = 0,
366 	READ_TYPE,
367 	UNKNOWN_TYPE,
368 };
369 
370 /*
371  * SRB status codes and masks; a subset of the codes used here.
372  */
373 
374 #define SRB_STATUS_AUTOSENSE_VALID	0x80
375 #define SRB_STATUS_QUEUE_FROZEN		0x40
376 #define SRB_STATUS_INVALID_LUN	0x20
377 #define SRB_STATUS_SUCCESS	0x01
378 #define SRB_STATUS_ABORTED	0x02
379 #define SRB_STATUS_ERROR	0x04
380 #define SRB_STATUS_DATA_OVERRUN	0x12
381 
382 #define SRB_STATUS(status) \
383 	(status & ~(SRB_STATUS_AUTOSENSE_VALID | SRB_STATUS_QUEUE_FROZEN))
384 /*
385  * This is the end of Protocol specific defines.
386  */
387 
388 static int storvsc_ringbuffer_size = (256 * PAGE_SIZE);
389 static u32 max_outstanding_req_per_channel;
390 
391 static int storvsc_vcpus_per_sub_channel = 4;
392 
393 module_param(storvsc_ringbuffer_size, int, S_IRUGO);
394 MODULE_PARM_DESC(storvsc_ringbuffer_size, "Ring buffer size (bytes)");
395 
396 module_param(storvsc_vcpus_per_sub_channel, int, S_IRUGO);
397 MODULE_PARM_DESC(storvsc_vcpus_per_sub_channel, "Ratio of VCPUs to subchannels");
398 /*
399  * Timeout in seconds for all devices managed by this driver.
400  */
401 static int storvsc_timeout = 180;
402 
403 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
404 static struct scsi_transport_template *fc_transport_template;
405 #endif
406 
407 static void storvsc_on_channel_callback(void *context);
408 
409 #define STORVSC_MAX_LUNS_PER_TARGET			255
410 #define STORVSC_MAX_TARGETS				2
411 #define STORVSC_MAX_CHANNELS				8
412 
413 #define STORVSC_FC_MAX_LUNS_PER_TARGET			255
414 #define STORVSC_FC_MAX_TARGETS				128
415 #define STORVSC_FC_MAX_CHANNELS				8
416 
417 #define STORVSC_IDE_MAX_LUNS_PER_TARGET			64
418 #define STORVSC_IDE_MAX_TARGETS				1
419 #define STORVSC_IDE_MAX_CHANNELS			1
420 
421 struct storvsc_cmd_request {
422 	struct scsi_cmnd *cmd;
423 
424 	struct hv_device *device;
425 
426 	/* Synchronize the request/response if needed */
427 	struct completion wait_event;
428 
429 	struct vmbus_channel_packet_multipage_buffer mpb;
430 	struct vmbus_packet_mpb_array *payload;
431 	u32 payload_sz;
432 
433 	struct vstor_packet vstor_packet;
434 };
435 
436 
437 /* A storvsc device is a device object that contains a vmbus channel */
438 struct storvsc_device {
439 	struct hv_device *device;
440 
441 	bool	 destroy;
442 	bool	 drain_notify;
443 	bool	 open_sub_channel;
444 	atomic_t num_outstanding_req;
445 	struct Scsi_Host *host;
446 
447 	wait_queue_head_t waiting_to_drain;
448 
449 	/*
450 	 * Each unique Port/Path/Target represents 1 channel ie scsi
451 	 * controller. In reality, the pathid, targetid is always 0
452 	 * and the port is set by us
453 	 */
454 	unsigned int port_number;
455 	unsigned char path_id;
456 	unsigned char target_id;
457 
458 	/*
459 	 * Max I/O, the device can support.
460 	 */
461 	u32   max_transfer_bytes;
462 	/*
463 	 * Number of sub-channels we will open.
464 	 */
465 	u16 num_sc;
466 	struct vmbus_channel **stor_chns;
467 	/*
468 	 * Mask of CPUs bound to subchannels.
469 	 */
470 	struct cpumask alloced_cpus;
471 	/* Used for vsc/vsp channel reset process */
472 	struct storvsc_cmd_request init_request;
473 	struct storvsc_cmd_request reset_request;
474 	/*
475 	 * Currently active port and node names for FC devices.
476 	 */
477 	u64 node_name;
478 	u64 port_name;
479 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
480 	struct fc_rport *rport;
481 #endif
482 };
483 
484 struct hv_host_device {
485 	struct hv_device *dev;
486 	unsigned int port;
487 	unsigned char path;
488 	unsigned char target;
489 };
490 
491 struct storvsc_scan_work {
492 	struct work_struct work;
493 	struct Scsi_Host *host;
494 	u8 lun;
495 	u8 tgt_id;
496 };
497 
498 static void storvsc_device_scan(struct work_struct *work)
499 {
500 	struct storvsc_scan_work *wrk;
501 	struct scsi_device *sdev;
502 
503 	wrk = container_of(work, struct storvsc_scan_work, work);
504 
505 	sdev = scsi_device_lookup(wrk->host, 0, wrk->tgt_id, wrk->lun);
506 	if (!sdev)
507 		goto done;
508 	scsi_rescan_device(&sdev->sdev_gendev);
509 	scsi_device_put(sdev);
510 
511 done:
512 	kfree(wrk);
513 }
514 
515 static void storvsc_host_scan(struct work_struct *work)
516 {
517 	struct storvsc_scan_work *wrk;
518 	struct Scsi_Host *host;
519 	struct scsi_device *sdev;
520 
521 	wrk = container_of(work, struct storvsc_scan_work, work);
522 	host = wrk->host;
523 
524 	/*
525 	 * Before scanning the host, first check to see if any of the
526 	 * currrently known devices have been hot removed. We issue a
527 	 * "unit ready" command against all currently known devices.
528 	 * This I/O will result in an error for devices that have been
529 	 * removed. As part of handling the I/O error, we remove the device.
530 	 *
531 	 * When a LUN is added or removed, the host sends us a signal to
532 	 * scan the host. Thus we are forced to discover the LUNs that
533 	 * may have been removed this way.
534 	 */
535 	mutex_lock(&host->scan_mutex);
536 	shost_for_each_device(sdev, host)
537 		scsi_test_unit_ready(sdev, 1, 1, NULL);
538 	mutex_unlock(&host->scan_mutex);
539 	/*
540 	 * Now scan the host to discover LUNs that may have been added.
541 	 */
542 	scsi_scan_host(host);
543 
544 	kfree(wrk);
545 }
546 
547 static void storvsc_remove_lun(struct work_struct *work)
548 {
549 	struct storvsc_scan_work *wrk;
550 	struct scsi_device *sdev;
551 
552 	wrk = container_of(work, struct storvsc_scan_work, work);
553 	if (!scsi_host_get(wrk->host))
554 		goto done;
555 
556 	sdev = scsi_device_lookup(wrk->host, 0, wrk->tgt_id, wrk->lun);
557 
558 	if (sdev) {
559 		scsi_remove_device(sdev);
560 		scsi_device_put(sdev);
561 	}
562 	scsi_host_put(wrk->host);
563 
564 done:
565 	kfree(wrk);
566 }
567 
568 
569 /*
570  * We can get incoming messages from the host that are not in response to
571  * messages that we have sent out. An example of this would be messages
572  * received by the guest to notify dynamic addition/removal of LUNs. To
573  * deal with potential race conditions where the driver may be in the
574  * midst of being unloaded when we might receive an unsolicited message
575  * from the host, we have implemented a mechanism to gurantee sequential
576  * consistency:
577  *
578  * 1) Once the device is marked as being destroyed, we will fail all
579  *    outgoing messages.
580  * 2) We permit incoming messages when the device is being destroyed,
581  *    only to properly account for messages already sent out.
582  */
583 
584 static inline struct storvsc_device *get_out_stor_device(
585 					struct hv_device *device)
586 {
587 	struct storvsc_device *stor_device;
588 
589 	stor_device = hv_get_drvdata(device);
590 
591 	if (stor_device && stor_device->destroy)
592 		stor_device = NULL;
593 
594 	return stor_device;
595 }
596 
597 
598 static inline void storvsc_wait_to_drain(struct storvsc_device *dev)
599 {
600 	dev->drain_notify = true;
601 	wait_event(dev->waiting_to_drain,
602 		   atomic_read(&dev->num_outstanding_req) == 0);
603 	dev->drain_notify = false;
604 }
605 
606 static inline struct storvsc_device *get_in_stor_device(
607 					struct hv_device *device)
608 {
609 	struct storvsc_device *stor_device;
610 
611 	stor_device = hv_get_drvdata(device);
612 
613 	if (!stor_device)
614 		goto get_in_err;
615 
616 	/*
617 	 * If the device is being destroyed; allow incoming
618 	 * traffic only to cleanup outstanding requests.
619 	 */
620 
621 	if (stor_device->destroy  &&
622 		(atomic_read(&stor_device->num_outstanding_req) == 0))
623 		stor_device = NULL;
624 
625 get_in_err:
626 	return stor_device;
627 
628 }
629 
630 static void handle_sc_creation(struct vmbus_channel *new_sc)
631 {
632 	struct hv_device *device = new_sc->primary_channel->device_obj;
633 	struct storvsc_device *stor_device;
634 	struct vmstorage_channel_properties props;
635 
636 	stor_device = get_out_stor_device(device);
637 	if (!stor_device)
638 		return;
639 
640 	if (stor_device->open_sub_channel == false)
641 		return;
642 
643 	memset(&props, 0, sizeof(struct vmstorage_channel_properties));
644 
645 	vmbus_open(new_sc,
646 		   storvsc_ringbuffer_size,
647 		   storvsc_ringbuffer_size,
648 		   (void *)&props,
649 		   sizeof(struct vmstorage_channel_properties),
650 		   storvsc_on_channel_callback, new_sc);
651 
652 	if (new_sc->state == CHANNEL_OPENED_STATE) {
653 		stor_device->stor_chns[new_sc->target_cpu] = new_sc;
654 		cpumask_set_cpu(new_sc->target_cpu, &stor_device->alloced_cpus);
655 	}
656 }
657 
658 static void  handle_multichannel_storage(struct hv_device *device, int max_chns)
659 {
660 	struct storvsc_device *stor_device;
661 	int num_cpus = num_online_cpus();
662 	int num_sc;
663 	struct storvsc_cmd_request *request;
664 	struct vstor_packet *vstor_packet;
665 	int ret, t;
666 
667 	num_sc = ((max_chns > num_cpus) ? num_cpus : max_chns);
668 	stor_device = get_out_stor_device(device);
669 	if (!stor_device)
670 		return;
671 
672 	stor_device->num_sc = num_sc;
673 	request = &stor_device->init_request;
674 	vstor_packet = &request->vstor_packet;
675 
676 	stor_device->open_sub_channel = true;
677 	/*
678 	 * Establish a handler for dealing with subchannels.
679 	 */
680 	vmbus_set_sc_create_callback(device->channel, handle_sc_creation);
681 
682 	/*
683 	 * Check to see if sub-channels have already been created. This
684 	 * can happen when this driver is re-loaded after unloading.
685 	 */
686 
687 	if (vmbus_are_subchannels_present(device->channel))
688 		return;
689 
690 	stor_device->open_sub_channel = false;
691 	/*
692 	 * Request the host to create sub-channels.
693 	 */
694 	memset(request, 0, sizeof(struct storvsc_cmd_request));
695 	init_completion(&request->wait_event);
696 	vstor_packet->operation = VSTOR_OPERATION_CREATE_SUB_CHANNELS;
697 	vstor_packet->flags = REQUEST_COMPLETION_FLAG;
698 	vstor_packet->sub_channel_count = num_sc;
699 
700 	ret = vmbus_sendpacket(device->channel, vstor_packet,
701 			       (sizeof(struct vstor_packet) -
702 			       vmscsi_size_delta),
703 			       (unsigned long)request,
704 			       VM_PKT_DATA_INBAND,
705 			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
706 
707 	if (ret != 0)
708 		return;
709 
710 	t = wait_for_completion_timeout(&request->wait_event, 10*HZ);
711 	if (t == 0)
712 		return;
713 
714 	if (vstor_packet->operation != VSTOR_OPERATION_COMPLETE_IO ||
715 	    vstor_packet->status != 0)
716 		return;
717 
718 	/*
719 	 * Now that we created the sub-channels, invoke the check; this
720 	 * may trigger the callback.
721 	 */
722 	stor_device->open_sub_channel = true;
723 	vmbus_are_subchannels_present(device->channel);
724 }
725 
726 static void cache_wwn(struct storvsc_device *stor_device,
727 		      struct vstor_packet *vstor_packet)
728 {
729 	/*
730 	 * Cache the currently active port and node ww names.
731 	 */
732 	if (vstor_packet->wwn_packet.primary_active) {
733 		stor_device->node_name =
734 			wwn_to_u64(vstor_packet->wwn_packet.primary_node_wwn);
735 		stor_device->port_name =
736 			wwn_to_u64(vstor_packet->wwn_packet.primary_port_wwn);
737 	} else {
738 		stor_device->node_name =
739 			wwn_to_u64(vstor_packet->wwn_packet.secondary_node_wwn);
740 		stor_device->port_name =
741 			wwn_to_u64(vstor_packet->wwn_packet.secondary_port_wwn);
742 	}
743 }
744 
745 
746 static int storvsc_execute_vstor_op(struct hv_device *device,
747 				    struct storvsc_cmd_request *request,
748 				    bool status_check)
749 {
750 	struct vstor_packet *vstor_packet;
751 	int ret, t;
752 
753 	vstor_packet = &request->vstor_packet;
754 
755 	init_completion(&request->wait_event);
756 	vstor_packet->flags = REQUEST_COMPLETION_FLAG;
757 
758 	ret = vmbus_sendpacket(device->channel, vstor_packet,
759 			       (sizeof(struct vstor_packet) -
760 			       vmscsi_size_delta),
761 			       (unsigned long)request,
762 			       VM_PKT_DATA_INBAND,
763 			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
764 	if (ret != 0)
765 		return ret;
766 
767 	t = wait_for_completion_timeout(&request->wait_event, 5*HZ);
768 	if (t == 0)
769 		return -ETIMEDOUT;
770 
771 	if (!status_check)
772 		return ret;
773 
774 	if (vstor_packet->operation != VSTOR_OPERATION_COMPLETE_IO ||
775 	    vstor_packet->status != 0)
776 		return -EINVAL;
777 
778 	return ret;
779 }
780 
781 static int storvsc_channel_init(struct hv_device *device, bool is_fc)
782 {
783 	struct storvsc_device *stor_device;
784 	struct storvsc_cmd_request *request;
785 	struct vstor_packet *vstor_packet;
786 	int ret, i;
787 	int max_chns;
788 	bool process_sub_channels = false;
789 
790 	stor_device = get_out_stor_device(device);
791 	if (!stor_device)
792 		return -ENODEV;
793 
794 	request = &stor_device->init_request;
795 	vstor_packet = &request->vstor_packet;
796 
797 	/*
798 	 * Now, initiate the vsc/vsp initialization protocol on the open
799 	 * channel
800 	 */
801 	memset(request, 0, sizeof(struct storvsc_cmd_request));
802 	vstor_packet->operation = VSTOR_OPERATION_BEGIN_INITIALIZATION;
803 	ret = storvsc_execute_vstor_op(device, request, true);
804 	if (ret)
805 		return ret;
806 	/*
807 	 * Query host supported protocol version.
808 	 */
809 
810 	for (i = 0; i < ARRAY_SIZE(vmstor_protocols); i++) {
811 		/* reuse the packet for version range supported */
812 		memset(vstor_packet, 0, sizeof(struct vstor_packet));
813 		vstor_packet->operation =
814 			VSTOR_OPERATION_QUERY_PROTOCOL_VERSION;
815 
816 		vstor_packet->version.major_minor =
817 			vmstor_protocols[i].protocol_version;
818 
819 		/*
820 		 * The revision number is only used in Windows; set it to 0.
821 		 */
822 		vstor_packet->version.revision = 0;
823 		ret = storvsc_execute_vstor_op(device, request, false);
824 		if (ret != 0)
825 			return ret;
826 
827 		if (vstor_packet->operation != VSTOR_OPERATION_COMPLETE_IO)
828 			return -EINVAL;
829 
830 		if (vstor_packet->status == 0) {
831 			vmstor_proto_version =
832 				vmstor_protocols[i].protocol_version;
833 
834 			sense_buffer_size =
835 				vmstor_protocols[i].sense_buffer_size;
836 
837 			vmscsi_size_delta =
838 				vmstor_protocols[i].vmscsi_size_delta;
839 
840 			break;
841 		}
842 	}
843 
844 	if (vstor_packet->status != 0)
845 		return -EINVAL;
846 
847 
848 	memset(vstor_packet, 0, sizeof(struct vstor_packet));
849 	vstor_packet->operation = VSTOR_OPERATION_QUERY_PROPERTIES;
850 	ret = storvsc_execute_vstor_op(device, request, true);
851 	if (ret != 0)
852 		return ret;
853 
854 	/*
855 	 * Check to see if multi-channel support is there.
856 	 * Hosts that implement protocol version of 5.1 and above
857 	 * support multi-channel.
858 	 */
859 	max_chns = vstor_packet->storage_channel_properties.max_channel_cnt;
860 
861 	/*
862 	 * Allocate state to manage the sub-channels.
863 	 * We allocate an array based on the numbers of possible CPUs
864 	 * (Hyper-V does not support cpu online/offline).
865 	 * This Array will be sparseley populated with unique
866 	 * channels - primary + sub-channels.
867 	 * We will however populate all the slots to evenly distribute
868 	 * the load.
869 	 */
870 	stor_device->stor_chns = kcalloc(num_possible_cpus(), sizeof(void *),
871 					 GFP_KERNEL);
872 	if (stor_device->stor_chns == NULL)
873 		return -ENOMEM;
874 
875 	stor_device->stor_chns[device->channel->target_cpu] = device->channel;
876 	cpumask_set_cpu(device->channel->target_cpu,
877 			&stor_device->alloced_cpus);
878 
879 	if (vmstor_proto_version >= VMSTOR_PROTO_VERSION_WIN8) {
880 		if (vstor_packet->storage_channel_properties.flags &
881 		    STORAGE_CHANNEL_SUPPORTS_MULTI_CHANNEL)
882 			process_sub_channels = true;
883 	}
884 	stor_device->max_transfer_bytes =
885 		vstor_packet->storage_channel_properties.max_transfer_bytes;
886 
887 	if (!is_fc)
888 		goto done;
889 
890 	/*
891 	 * For FC devices retrieve FC HBA data.
892 	 */
893 	memset(vstor_packet, 0, sizeof(struct vstor_packet));
894 	vstor_packet->operation = VSTOR_OPERATION_FCHBA_DATA;
895 	ret = storvsc_execute_vstor_op(device, request, true);
896 	if (ret != 0)
897 		return ret;
898 
899 	/*
900 	 * Cache the currently active port and node ww names.
901 	 */
902 	cache_wwn(stor_device, vstor_packet);
903 
904 done:
905 
906 	memset(vstor_packet, 0, sizeof(struct vstor_packet));
907 	vstor_packet->operation = VSTOR_OPERATION_END_INITIALIZATION;
908 	ret = storvsc_execute_vstor_op(device, request, true);
909 	if (ret != 0)
910 		return ret;
911 
912 	if (process_sub_channels)
913 		handle_multichannel_storage(device, max_chns);
914 
915 	return ret;
916 }
917 
918 static void storvsc_handle_error(struct vmscsi_request *vm_srb,
919 				struct scsi_cmnd *scmnd,
920 				struct Scsi_Host *host,
921 				u8 asc, u8 ascq)
922 {
923 	struct storvsc_scan_work *wrk;
924 	void (*process_err_fn)(struct work_struct *work);
925 	bool do_work = false;
926 
927 	switch (SRB_STATUS(vm_srb->srb_status)) {
928 	case SRB_STATUS_ERROR:
929 		/*
930 		 * Let upper layer deal with error when
931 		 * sense message is present.
932 		 */
933 
934 		if (vm_srb->srb_status & SRB_STATUS_AUTOSENSE_VALID)
935 			break;
936 		/*
937 		 * If there is an error; offline the device since all
938 		 * error recovery strategies would have already been
939 		 * deployed on the host side. However, if the command
940 		 * were a pass-through command deal with it appropriately.
941 		 */
942 		switch (scmnd->cmnd[0]) {
943 		case ATA_16:
944 		case ATA_12:
945 			set_host_byte(scmnd, DID_PASSTHROUGH);
946 			break;
947 		/*
948 		 * On Some Windows hosts TEST_UNIT_READY command can return
949 		 * SRB_STATUS_ERROR, let the upper level code deal with it
950 		 * based on the sense information.
951 		 */
952 		case TEST_UNIT_READY:
953 			break;
954 		default:
955 			set_host_byte(scmnd, DID_TARGET_FAILURE);
956 		}
957 		break;
958 	case SRB_STATUS_INVALID_LUN:
959 		do_work = true;
960 		process_err_fn = storvsc_remove_lun;
961 		break;
962 	case SRB_STATUS_ABORTED:
963 		if (vm_srb->srb_status & SRB_STATUS_AUTOSENSE_VALID &&
964 		    (asc == 0x2a) && (ascq == 0x9)) {
965 			do_work = true;
966 			process_err_fn = storvsc_device_scan;
967 			/*
968 			 * Retry the I/O that trigerred this.
969 			 */
970 			set_host_byte(scmnd, DID_REQUEUE);
971 		}
972 		break;
973 	}
974 
975 	if (!do_work)
976 		return;
977 
978 	/*
979 	 * We need to schedule work to process this error; schedule it.
980 	 */
981 	wrk = kmalloc(sizeof(struct storvsc_scan_work), GFP_ATOMIC);
982 	if (!wrk) {
983 		set_host_byte(scmnd, DID_TARGET_FAILURE);
984 		return;
985 	}
986 
987 	wrk->host = host;
988 	wrk->lun = vm_srb->lun;
989 	wrk->tgt_id = vm_srb->target_id;
990 	INIT_WORK(&wrk->work, process_err_fn);
991 	schedule_work(&wrk->work);
992 }
993 
994 
995 static void storvsc_command_completion(struct storvsc_cmd_request *cmd_request,
996 				       struct storvsc_device *stor_dev)
997 {
998 	struct scsi_cmnd *scmnd = cmd_request->cmd;
999 	struct scsi_sense_hdr sense_hdr;
1000 	struct vmscsi_request *vm_srb;
1001 	u32 data_transfer_length;
1002 	struct Scsi_Host *host;
1003 	u32 payload_sz = cmd_request->payload_sz;
1004 	void *payload = cmd_request->payload;
1005 
1006 	host = stor_dev->host;
1007 
1008 	vm_srb = &cmd_request->vstor_packet.vm_srb;
1009 	data_transfer_length = vm_srb->data_transfer_length;
1010 
1011 	scmnd->result = vm_srb->scsi_status;
1012 
1013 	if (scmnd->result) {
1014 		if (scsi_normalize_sense(scmnd->sense_buffer,
1015 				SCSI_SENSE_BUFFERSIZE, &sense_hdr) &&
1016 		    !(sense_hdr.sense_key == NOT_READY &&
1017 				 sense_hdr.asc == 0x03A) &&
1018 		    do_logging(STORVSC_LOGGING_ERROR))
1019 			scsi_print_sense_hdr(scmnd->device, "storvsc",
1020 					     &sense_hdr);
1021 	}
1022 
1023 	if (vm_srb->srb_status != SRB_STATUS_SUCCESS) {
1024 		storvsc_handle_error(vm_srb, scmnd, host, sense_hdr.asc,
1025 					 sense_hdr.ascq);
1026 		/*
1027 		 * The Windows driver set data_transfer_length on
1028 		 * SRB_STATUS_DATA_OVERRUN. On other errors, this value
1029 		 * is untouched.  In these cases we set it to 0.
1030 		 */
1031 		if (vm_srb->srb_status != SRB_STATUS_DATA_OVERRUN)
1032 			data_transfer_length = 0;
1033 	}
1034 
1035 	scsi_set_resid(scmnd,
1036 		cmd_request->payload->range.len - data_transfer_length);
1037 
1038 	scmnd->scsi_done(scmnd);
1039 
1040 	if (payload_sz >
1041 		sizeof(struct vmbus_channel_packet_multipage_buffer))
1042 		kfree(payload);
1043 }
1044 
1045 static void storvsc_on_io_completion(struct storvsc_device *stor_device,
1046 				  struct vstor_packet *vstor_packet,
1047 				  struct storvsc_cmd_request *request)
1048 {
1049 	struct vstor_packet *stor_pkt;
1050 	struct hv_device *device = stor_device->device;
1051 
1052 	stor_pkt = &request->vstor_packet;
1053 
1054 	/*
1055 	 * The current SCSI handling on the host side does
1056 	 * not correctly handle:
1057 	 * INQUIRY command with page code parameter set to 0x80
1058 	 * MODE_SENSE command with cmd[2] == 0x1c
1059 	 *
1060 	 * Setup srb and scsi status so this won't be fatal.
1061 	 * We do this so we can distinguish truly fatal failues
1062 	 * (srb status == 0x4) and off-line the device in that case.
1063 	 */
1064 
1065 	if ((stor_pkt->vm_srb.cdb[0] == INQUIRY) ||
1066 	   (stor_pkt->vm_srb.cdb[0] == MODE_SENSE)) {
1067 		vstor_packet->vm_srb.scsi_status = 0;
1068 		vstor_packet->vm_srb.srb_status = SRB_STATUS_SUCCESS;
1069 	}
1070 
1071 
1072 	/* Copy over the status...etc */
1073 	stor_pkt->vm_srb.scsi_status = vstor_packet->vm_srb.scsi_status;
1074 	stor_pkt->vm_srb.srb_status = vstor_packet->vm_srb.srb_status;
1075 	stor_pkt->vm_srb.sense_info_length =
1076 	vstor_packet->vm_srb.sense_info_length;
1077 
1078 	if (vstor_packet->vm_srb.scsi_status != 0 ||
1079 	    vstor_packet->vm_srb.srb_status != SRB_STATUS_SUCCESS)
1080 		storvsc_log(device, STORVSC_LOGGING_WARN,
1081 			"cmd 0x%x scsi status 0x%x srb status 0x%x\n",
1082 			stor_pkt->vm_srb.cdb[0],
1083 			vstor_packet->vm_srb.scsi_status,
1084 			vstor_packet->vm_srb.srb_status);
1085 
1086 	if ((vstor_packet->vm_srb.scsi_status & 0xFF) == 0x02) {
1087 		/* CHECK_CONDITION */
1088 		if (vstor_packet->vm_srb.srb_status &
1089 			SRB_STATUS_AUTOSENSE_VALID) {
1090 			/* autosense data available */
1091 
1092 			storvsc_log(device, STORVSC_LOGGING_WARN,
1093 				"stor pkt %p autosense data valid - len %d\n",
1094 				request, vstor_packet->vm_srb.sense_info_length);
1095 
1096 			memcpy(request->cmd->sense_buffer,
1097 			       vstor_packet->vm_srb.sense_data,
1098 			       vstor_packet->vm_srb.sense_info_length);
1099 
1100 		}
1101 	}
1102 
1103 	stor_pkt->vm_srb.data_transfer_length =
1104 	vstor_packet->vm_srb.data_transfer_length;
1105 
1106 	storvsc_command_completion(request, stor_device);
1107 
1108 	if (atomic_dec_and_test(&stor_device->num_outstanding_req) &&
1109 		stor_device->drain_notify)
1110 		wake_up(&stor_device->waiting_to_drain);
1111 
1112 
1113 }
1114 
1115 static void storvsc_on_receive(struct storvsc_device *stor_device,
1116 			     struct vstor_packet *vstor_packet,
1117 			     struct storvsc_cmd_request *request)
1118 {
1119 	struct storvsc_scan_work *work;
1120 
1121 	switch (vstor_packet->operation) {
1122 	case VSTOR_OPERATION_COMPLETE_IO:
1123 		storvsc_on_io_completion(stor_device, vstor_packet, request);
1124 		break;
1125 
1126 	case VSTOR_OPERATION_REMOVE_DEVICE:
1127 	case VSTOR_OPERATION_ENUMERATE_BUS:
1128 		work = kmalloc(sizeof(struct storvsc_scan_work), GFP_ATOMIC);
1129 		if (!work)
1130 			return;
1131 
1132 		INIT_WORK(&work->work, storvsc_host_scan);
1133 		work->host = stor_device->host;
1134 		schedule_work(&work->work);
1135 		break;
1136 
1137 	case VSTOR_OPERATION_FCHBA_DATA:
1138 		cache_wwn(stor_device, vstor_packet);
1139 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
1140 		fc_host_node_name(stor_device->host) = stor_device->node_name;
1141 		fc_host_port_name(stor_device->host) = stor_device->port_name;
1142 #endif
1143 		break;
1144 	default:
1145 		break;
1146 	}
1147 }
1148 
1149 static void storvsc_on_channel_callback(void *context)
1150 {
1151 	struct vmbus_channel *channel = (struct vmbus_channel *)context;
1152 	const struct vmpacket_descriptor *desc;
1153 	struct hv_device *device;
1154 	struct storvsc_device *stor_device;
1155 
1156 	if (channel->primary_channel != NULL)
1157 		device = channel->primary_channel->device_obj;
1158 	else
1159 		device = channel->device_obj;
1160 
1161 	stor_device = get_in_stor_device(device);
1162 	if (!stor_device)
1163 		return;
1164 
1165 	foreach_vmbus_pkt(desc, channel) {
1166 		void *packet = hv_pkt_data(desc);
1167 		struct storvsc_cmd_request *request;
1168 
1169 		request = (struct storvsc_cmd_request *)
1170 			((unsigned long)desc->trans_id);
1171 
1172 		if (request == &stor_device->init_request ||
1173 		    request == &stor_device->reset_request) {
1174 			memcpy(&request->vstor_packet, packet,
1175 			       (sizeof(struct vstor_packet) - vmscsi_size_delta));
1176 			complete(&request->wait_event);
1177 		} else {
1178 			storvsc_on_receive(stor_device, packet, request);
1179 		}
1180 	}
1181 }
1182 
1183 static int storvsc_connect_to_vsp(struct hv_device *device, u32 ring_size,
1184 				  bool is_fc)
1185 {
1186 	struct vmstorage_channel_properties props;
1187 	int ret;
1188 
1189 	memset(&props, 0, sizeof(struct vmstorage_channel_properties));
1190 
1191 	ret = vmbus_open(device->channel,
1192 			 ring_size,
1193 			 ring_size,
1194 			 (void *)&props,
1195 			 sizeof(struct vmstorage_channel_properties),
1196 			 storvsc_on_channel_callback, device->channel);
1197 
1198 	if (ret != 0)
1199 		return ret;
1200 
1201 	ret = storvsc_channel_init(device, is_fc);
1202 
1203 	return ret;
1204 }
1205 
1206 static int storvsc_dev_remove(struct hv_device *device)
1207 {
1208 	struct storvsc_device *stor_device;
1209 
1210 	stor_device = hv_get_drvdata(device);
1211 
1212 	stor_device->destroy = true;
1213 
1214 	/* Make sure flag is set before waiting */
1215 	wmb();
1216 
1217 	/*
1218 	 * At this point, all outbound traffic should be disable. We
1219 	 * only allow inbound traffic (responses) to proceed so that
1220 	 * outstanding requests can be completed.
1221 	 */
1222 
1223 	storvsc_wait_to_drain(stor_device);
1224 
1225 	/*
1226 	 * Since we have already drained, we don't need to busy wait
1227 	 * as was done in final_release_stor_device()
1228 	 * Note that we cannot set the ext pointer to NULL until
1229 	 * we have drained - to drain the outgoing packets, we need to
1230 	 * allow incoming packets.
1231 	 */
1232 	hv_set_drvdata(device, NULL);
1233 
1234 	/* Close the channel */
1235 	vmbus_close(device->channel);
1236 
1237 	kfree(stor_device->stor_chns);
1238 	kfree(stor_device);
1239 	return 0;
1240 }
1241 
1242 static struct vmbus_channel *get_og_chn(struct storvsc_device *stor_device,
1243 					u16 q_num)
1244 {
1245 	u16 slot = 0;
1246 	u16 hash_qnum;
1247 	struct cpumask alloced_mask;
1248 	int num_channels, tgt_cpu;
1249 
1250 	if (stor_device->num_sc == 0)
1251 		return stor_device->device->channel;
1252 
1253 	/*
1254 	 * Our channel array is sparsley populated and we
1255 	 * initiated I/O on a processor/hw-q that does not
1256 	 * currently have a designated channel. Fix this.
1257 	 * The strategy is simple:
1258 	 * I. Ensure NUMA locality
1259 	 * II. Distribute evenly (best effort)
1260 	 * III. Mapping is persistent.
1261 	 */
1262 
1263 	cpumask_and(&alloced_mask, &stor_device->alloced_cpus,
1264 		    cpumask_of_node(cpu_to_node(q_num)));
1265 
1266 	num_channels = cpumask_weight(&alloced_mask);
1267 	if (num_channels == 0)
1268 		return stor_device->device->channel;
1269 
1270 	hash_qnum = q_num;
1271 	while (hash_qnum >= num_channels)
1272 		hash_qnum -= num_channels;
1273 
1274 	for_each_cpu(tgt_cpu, &alloced_mask) {
1275 		if (slot == hash_qnum)
1276 			break;
1277 		slot++;
1278 	}
1279 
1280 	stor_device->stor_chns[q_num] = stor_device->stor_chns[tgt_cpu];
1281 
1282 	return stor_device->stor_chns[q_num];
1283 }
1284 
1285 
1286 static int storvsc_do_io(struct hv_device *device,
1287 			 struct storvsc_cmd_request *request, u16 q_num)
1288 {
1289 	struct storvsc_device *stor_device;
1290 	struct vstor_packet *vstor_packet;
1291 	struct vmbus_channel *outgoing_channel;
1292 	int ret = 0;
1293 	struct cpumask alloced_mask;
1294 	int tgt_cpu;
1295 
1296 	vstor_packet = &request->vstor_packet;
1297 	stor_device = get_out_stor_device(device);
1298 
1299 	if (!stor_device)
1300 		return -ENODEV;
1301 
1302 
1303 	request->device  = device;
1304 	/*
1305 	 * Select an an appropriate channel to send the request out.
1306 	 */
1307 
1308 	if (stor_device->stor_chns[q_num] != NULL) {
1309 		outgoing_channel = stor_device->stor_chns[q_num];
1310 		if (outgoing_channel->target_cpu == smp_processor_id()) {
1311 			/*
1312 			 * Ideally, we want to pick a different channel if
1313 			 * available on the same NUMA node.
1314 			 */
1315 			cpumask_and(&alloced_mask, &stor_device->alloced_cpus,
1316 				    cpumask_of_node(cpu_to_node(q_num)));
1317 			for_each_cpu(tgt_cpu, &alloced_mask) {
1318 				if (tgt_cpu != outgoing_channel->target_cpu) {
1319 					outgoing_channel =
1320 					stor_device->stor_chns[tgt_cpu];
1321 					break;
1322 				}
1323 			}
1324 		}
1325 	} else {
1326 		outgoing_channel = get_og_chn(stor_device, q_num);
1327 	}
1328 
1329 
1330 	vstor_packet->flags |= REQUEST_COMPLETION_FLAG;
1331 
1332 	vstor_packet->vm_srb.length = (sizeof(struct vmscsi_request) -
1333 					vmscsi_size_delta);
1334 
1335 
1336 	vstor_packet->vm_srb.sense_info_length = sense_buffer_size;
1337 
1338 
1339 	vstor_packet->vm_srb.data_transfer_length =
1340 	request->payload->range.len;
1341 
1342 	vstor_packet->operation = VSTOR_OPERATION_EXECUTE_SRB;
1343 
1344 	if (request->payload->range.len) {
1345 
1346 		ret = vmbus_sendpacket_mpb_desc(outgoing_channel,
1347 				request->payload, request->payload_sz,
1348 				vstor_packet,
1349 				(sizeof(struct vstor_packet) -
1350 				vmscsi_size_delta),
1351 				(unsigned long)request);
1352 	} else {
1353 		ret = vmbus_sendpacket(outgoing_channel, vstor_packet,
1354 			       (sizeof(struct vstor_packet) -
1355 				vmscsi_size_delta),
1356 			       (unsigned long)request,
1357 			       VM_PKT_DATA_INBAND,
1358 			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
1359 	}
1360 
1361 	if (ret != 0)
1362 		return ret;
1363 
1364 	atomic_inc(&stor_device->num_outstanding_req);
1365 
1366 	return ret;
1367 }
1368 
1369 static int storvsc_device_alloc(struct scsi_device *sdevice)
1370 {
1371 	/*
1372 	 * Set blist flag to permit the reading of the VPD pages even when
1373 	 * the target may claim SPC-2 compliance. MSFT targets currently
1374 	 * claim SPC-2 compliance while they implement post SPC-2 features.
1375 	 * With this flag we can correctly handle WRITE_SAME_16 issues.
1376 	 *
1377 	 * Hypervisor reports SCSI_UNKNOWN type for DVD ROM device but
1378 	 * still supports REPORT LUN.
1379 	 */
1380 	sdevice->sdev_bflags = BLIST_REPORTLUN2 | BLIST_TRY_VPD_PAGES;
1381 
1382 	return 0;
1383 }
1384 
1385 static int storvsc_device_configure(struct scsi_device *sdevice)
1386 {
1387 
1388 	blk_queue_bounce_limit(sdevice->request_queue, BLK_BOUNCE_ANY);
1389 
1390 	blk_queue_rq_timeout(sdevice->request_queue, (storvsc_timeout * HZ));
1391 
1392 	/* Ensure there are no gaps in presented sgls */
1393 	blk_queue_virt_boundary(sdevice->request_queue, PAGE_SIZE - 1);
1394 
1395 	sdevice->no_write_same = 1;
1396 
1397 	/*
1398 	 * If the host is WIN8 or WIN8 R2, claim conformance to SPC-3
1399 	 * if the device is a MSFT virtual device.  If the host is
1400 	 * WIN10 or newer, allow write_same.
1401 	 */
1402 	if (!strncmp(sdevice->vendor, "Msft", 4)) {
1403 		switch (vmstor_proto_version) {
1404 		case VMSTOR_PROTO_VERSION_WIN8:
1405 		case VMSTOR_PROTO_VERSION_WIN8_1:
1406 			sdevice->scsi_level = SCSI_SPC_3;
1407 			break;
1408 		}
1409 
1410 		if (vmstor_proto_version >= VMSTOR_PROTO_VERSION_WIN10)
1411 			sdevice->no_write_same = 0;
1412 	}
1413 
1414 	return 0;
1415 }
1416 
1417 static int storvsc_get_chs(struct scsi_device *sdev, struct block_device * bdev,
1418 			   sector_t capacity, int *info)
1419 {
1420 	sector_t nsect = capacity;
1421 	sector_t cylinders = nsect;
1422 	int heads, sectors_pt;
1423 
1424 	/*
1425 	 * We are making up these values; let us keep it simple.
1426 	 */
1427 	heads = 0xff;
1428 	sectors_pt = 0x3f;      /* Sectors per track */
1429 	sector_div(cylinders, heads * sectors_pt);
1430 	if ((sector_t)(cylinders + 1) * heads * sectors_pt < nsect)
1431 		cylinders = 0xffff;
1432 
1433 	info[0] = heads;
1434 	info[1] = sectors_pt;
1435 	info[2] = (int)cylinders;
1436 
1437 	return 0;
1438 }
1439 
1440 static int storvsc_host_reset_handler(struct scsi_cmnd *scmnd)
1441 {
1442 	struct hv_host_device *host_dev = shost_priv(scmnd->device->host);
1443 	struct hv_device *device = host_dev->dev;
1444 
1445 	struct storvsc_device *stor_device;
1446 	struct storvsc_cmd_request *request;
1447 	struct vstor_packet *vstor_packet;
1448 	int ret, t;
1449 
1450 
1451 	stor_device = get_out_stor_device(device);
1452 	if (!stor_device)
1453 		return FAILED;
1454 
1455 	request = &stor_device->reset_request;
1456 	vstor_packet = &request->vstor_packet;
1457 
1458 	init_completion(&request->wait_event);
1459 
1460 	vstor_packet->operation = VSTOR_OPERATION_RESET_BUS;
1461 	vstor_packet->flags = REQUEST_COMPLETION_FLAG;
1462 	vstor_packet->vm_srb.path_id = stor_device->path_id;
1463 
1464 	ret = vmbus_sendpacket(device->channel, vstor_packet,
1465 			       (sizeof(struct vstor_packet) -
1466 				vmscsi_size_delta),
1467 			       (unsigned long)&stor_device->reset_request,
1468 			       VM_PKT_DATA_INBAND,
1469 			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
1470 	if (ret != 0)
1471 		return FAILED;
1472 
1473 	t = wait_for_completion_timeout(&request->wait_event, 5*HZ);
1474 	if (t == 0)
1475 		return TIMEOUT_ERROR;
1476 
1477 
1478 	/*
1479 	 * At this point, all outstanding requests in the adapter
1480 	 * should have been flushed out and return to us
1481 	 * There is a potential race here where the host may be in
1482 	 * the process of responding when we return from here.
1483 	 * Just wait for all in-transit packets to be accounted for
1484 	 * before we return from here.
1485 	 */
1486 	storvsc_wait_to_drain(stor_device);
1487 
1488 	return SUCCESS;
1489 }
1490 
1491 /*
1492  * The host guarantees to respond to each command, although I/O latencies might
1493  * be unbounded on Azure.  Reset the timer unconditionally to give the host a
1494  * chance to perform EH.
1495  */
1496 static enum blk_eh_timer_return storvsc_eh_timed_out(struct scsi_cmnd *scmnd)
1497 {
1498 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
1499 	if (scmnd->device->host->transportt == fc_transport_template)
1500 		return fc_eh_timed_out(scmnd);
1501 #endif
1502 	return BLK_EH_RESET_TIMER;
1503 }
1504 
1505 static bool storvsc_scsi_cmd_ok(struct scsi_cmnd *scmnd)
1506 {
1507 	bool allowed = true;
1508 	u8 scsi_op = scmnd->cmnd[0];
1509 
1510 	switch (scsi_op) {
1511 	/* the host does not handle WRITE_SAME, log accident usage */
1512 	case WRITE_SAME:
1513 	/*
1514 	 * smartd sends this command and the host does not handle
1515 	 * this. So, don't send it.
1516 	 */
1517 	case SET_WINDOW:
1518 		scmnd->result = ILLEGAL_REQUEST << 16;
1519 		allowed = false;
1520 		break;
1521 	default:
1522 		break;
1523 	}
1524 	return allowed;
1525 }
1526 
1527 static int storvsc_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *scmnd)
1528 {
1529 	int ret;
1530 	struct hv_host_device *host_dev = shost_priv(host);
1531 	struct hv_device *dev = host_dev->dev;
1532 	struct storvsc_cmd_request *cmd_request = scsi_cmd_priv(scmnd);
1533 	int i;
1534 	struct scatterlist *sgl;
1535 	unsigned int sg_count = 0;
1536 	struct vmscsi_request *vm_srb;
1537 	struct scatterlist *cur_sgl;
1538 	struct vmbus_packet_mpb_array  *payload;
1539 	u32 payload_sz;
1540 	u32 length;
1541 
1542 	if (vmstor_proto_version <= VMSTOR_PROTO_VERSION_WIN8) {
1543 		/*
1544 		 * On legacy hosts filter unimplemented commands.
1545 		 * Future hosts are expected to correctly handle
1546 		 * unsupported commands. Furthermore, it is
1547 		 * possible that some of the currently
1548 		 * unsupported commands maybe supported in
1549 		 * future versions of the host.
1550 		 */
1551 		if (!storvsc_scsi_cmd_ok(scmnd)) {
1552 			scmnd->scsi_done(scmnd);
1553 			return 0;
1554 		}
1555 	}
1556 
1557 	/* Setup the cmd request */
1558 	cmd_request->cmd = scmnd;
1559 
1560 	vm_srb = &cmd_request->vstor_packet.vm_srb;
1561 	vm_srb->win8_extension.time_out_value = 60;
1562 
1563 	vm_srb->win8_extension.srb_flags |=
1564 		SRB_FLAGS_DISABLE_SYNCH_TRANSFER;
1565 
1566 	if (scmnd->device->tagged_supported) {
1567 		vm_srb->win8_extension.srb_flags |=
1568 		(SRB_FLAGS_QUEUE_ACTION_ENABLE | SRB_FLAGS_NO_QUEUE_FREEZE);
1569 		vm_srb->win8_extension.queue_tag = SP_UNTAGGED;
1570 		vm_srb->win8_extension.queue_action = SRB_SIMPLE_TAG_REQUEST;
1571 	}
1572 
1573 	/* Build the SRB */
1574 	switch (scmnd->sc_data_direction) {
1575 	case DMA_TO_DEVICE:
1576 		vm_srb->data_in = WRITE_TYPE;
1577 		vm_srb->win8_extension.srb_flags |= SRB_FLAGS_DATA_OUT;
1578 		break;
1579 	case DMA_FROM_DEVICE:
1580 		vm_srb->data_in = READ_TYPE;
1581 		vm_srb->win8_extension.srb_flags |= SRB_FLAGS_DATA_IN;
1582 		break;
1583 	case DMA_NONE:
1584 		vm_srb->data_in = UNKNOWN_TYPE;
1585 		vm_srb->win8_extension.srb_flags |= SRB_FLAGS_NO_DATA_TRANSFER;
1586 		break;
1587 	default:
1588 		/*
1589 		 * This is DMA_BIDIRECTIONAL or something else we are never
1590 		 * supposed to see here.
1591 		 */
1592 		WARN(1, "Unexpected data direction: %d\n",
1593 		     scmnd->sc_data_direction);
1594 		return -EINVAL;
1595 	}
1596 
1597 
1598 	vm_srb->port_number = host_dev->port;
1599 	vm_srb->path_id = scmnd->device->channel;
1600 	vm_srb->target_id = scmnd->device->id;
1601 	vm_srb->lun = scmnd->device->lun;
1602 
1603 	vm_srb->cdb_length = scmnd->cmd_len;
1604 
1605 	memcpy(vm_srb->cdb, scmnd->cmnd, vm_srb->cdb_length);
1606 
1607 	sgl = (struct scatterlist *)scsi_sglist(scmnd);
1608 	sg_count = scsi_sg_count(scmnd);
1609 
1610 	length = scsi_bufflen(scmnd);
1611 	payload = (struct vmbus_packet_mpb_array *)&cmd_request->mpb;
1612 	payload_sz = sizeof(cmd_request->mpb);
1613 
1614 	if (sg_count) {
1615 		if (sg_count > MAX_PAGE_BUFFER_COUNT) {
1616 
1617 			payload_sz = (sg_count * sizeof(u64) +
1618 				      sizeof(struct vmbus_packet_mpb_array));
1619 			payload = kzalloc(payload_sz, GFP_ATOMIC);
1620 			if (!payload)
1621 				return SCSI_MLQUEUE_DEVICE_BUSY;
1622 		}
1623 
1624 		payload->range.len = length;
1625 		payload->range.offset = sgl[0].offset;
1626 
1627 		cur_sgl = sgl;
1628 		for (i = 0; i < sg_count; i++) {
1629 			payload->range.pfn_array[i] =
1630 				page_to_pfn(sg_page((cur_sgl)));
1631 			cur_sgl = sg_next(cur_sgl);
1632 		}
1633 	}
1634 
1635 	cmd_request->payload = payload;
1636 	cmd_request->payload_sz = payload_sz;
1637 
1638 	/* Invokes the vsc to start an IO */
1639 	ret = storvsc_do_io(dev, cmd_request, get_cpu());
1640 	put_cpu();
1641 
1642 	if (ret == -EAGAIN) {
1643 		/* no more space */
1644 		return SCSI_MLQUEUE_DEVICE_BUSY;
1645 	}
1646 
1647 	return 0;
1648 }
1649 
1650 static struct scsi_host_template scsi_driver = {
1651 	.module	=		THIS_MODULE,
1652 	.name =			"storvsc_host_t",
1653 	.cmd_size =             sizeof(struct storvsc_cmd_request),
1654 	.bios_param =		storvsc_get_chs,
1655 	.queuecommand =		storvsc_queuecommand,
1656 	.eh_host_reset_handler =	storvsc_host_reset_handler,
1657 	.proc_name =		"storvsc_host",
1658 	.eh_timed_out =		storvsc_eh_timed_out,
1659 	.slave_alloc =		storvsc_device_alloc,
1660 	.slave_configure =	storvsc_device_configure,
1661 	.cmd_per_lun =		255,
1662 	.this_id =		-1,
1663 	.use_clustering =	ENABLE_CLUSTERING,
1664 	/* Make sure we dont get a sg segment crosses a page boundary */
1665 	.dma_boundary =		PAGE_SIZE-1,
1666 	.no_write_same =	1,
1667 	.track_queue_depth =	1,
1668 };
1669 
1670 enum {
1671 	SCSI_GUID,
1672 	IDE_GUID,
1673 	SFC_GUID,
1674 };
1675 
1676 static const struct hv_vmbus_device_id id_table[] = {
1677 	/* SCSI guid */
1678 	{ HV_SCSI_GUID,
1679 	  .driver_data = SCSI_GUID
1680 	},
1681 	/* IDE guid */
1682 	{ HV_IDE_GUID,
1683 	  .driver_data = IDE_GUID
1684 	},
1685 	/* Fibre Channel GUID */
1686 	{
1687 	  HV_SYNTHFC_GUID,
1688 	  .driver_data = SFC_GUID
1689 	},
1690 	{ },
1691 };
1692 
1693 MODULE_DEVICE_TABLE(vmbus, id_table);
1694 
1695 static int storvsc_probe(struct hv_device *device,
1696 			const struct hv_vmbus_device_id *dev_id)
1697 {
1698 	int ret;
1699 	int num_cpus = num_online_cpus();
1700 	struct Scsi_Host *host;
1701 	struct hv_host_device *host_dev;
1702 	bool dev_is_ide = ((dev_id->driver_data == IDE_GUID) ? true : false);
1703 	bool is_fc = ((dev_id->driver_data == SFC_GUID) ? true : false);
1704 	int target = 0;
1705 	struct storvsc_device *stor_device;
1706 	int max_luns_per_target;
1707 	int max_targets;
1708 	int max_channels;
1709 	int max_sub_channels = 0;
1710 
1711 	/*
1712 	 * Based on the windows host we are running on,
1713 	 * set state to properly communicate with the host.
1714 	 */
1715 
1716 	if (vmbus_proto_version < VERSION_WIN8) {
1717 		max_luns_per_target = STORVSC_IDE_MAX_LUNS_PER_TARGET;
1718 		max_targets = STORVSC_IDE_MAX_TARGETS;
1719 		max_channels = STORVSC_IDE_MAX_CHANNELS;
1720 	} else {
1721 		max_luns_per_target = STORVSC_MAX_LUNS_PER_TARGET;
1722 		max_targets = STORVSC_MAX_TARGETS;
1723 		max_channels = STORVSC_MAX_CHANNELS;
1724 		/*
1725 		 * On Windows8 and above, we support sub-channels for storage.
1726 		 * The number of sub-channels offerred is based on the number of
1727 		 * VCPUs in the guest.
1728 		 */
1729 		max_sub_channels = (num_cpus / storvsc_vcpus_per_sub_channel);
1730 	}
1731 
1732 	scsi_driver.can_queue = (max_outstanding_req_per_channel *
1733 				 (max_sub_channels + 1));
1734 
1735 	host = scsi_host_alloc(&scsi_driver,
1736 			       sizeof(struct hv_host_device));
1737 	if (!host)
1738 		return -ENOMEM;
1739 
1740 	host_dev = shost_priv(host);
1741 	memset(host_dev, 0, sizeof(struct hv_host_device));
1742 
1743 	host_dev->port = host->host_no;
1744 	host_dev->dev = device;
1745 
1746 
1747 	stor_device = kzalloc(sizeof(struct storvsc_device), GFP_KERNEL);
1748 	if (!stor_device) {
1749 		ret = -ENOMEM;
1750 		goto err_out0;
1751 	}
1752 
1753 	stor_device->destroy = false;
1754 	stor_device->open_sub_channel = false;
1755 	init_waitqueue_head(&stor_device->waiting_to_drain);
1756 	stor_device->device = device;
1757 	stor_device->host = host;
1758 	hv_set_drvdata(device, stor_device);
1759 
1760 	stor_device->port_number = host->host_no;
1761 	ret = storvsc_connect_to_vsp(device, storvsc_ringbuffer_size, is_fc);
1762 	if (ret)
1763 		goto err_out1;
1764 
1765 	host_dev->path = stor_device->path_id;
1766 	host_dev->target = stor_device->target_id;
1767 
1768 	switch (dev_id->driver_data) {
1769 	case SFC_GUID:
1770 		host->max_lun = STORVSC_FC_MAX_LUNS_PER_TARGET;
1771 		host->max_id = STORVSC_FC_MAX_TARGETS;
1772 		host->max_channel = STORVSC_FC_MAX_CHANNELS - 1;
1773 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
1774 		host->transportt = fc_transport_template;
1775 #endif
1776 		break;
1777 
1778 	case SCSI_GUID:
1779 		host->max_lun = max_luns_per_target;
1780 		host->max_id = max_targets;
1781 		host->max_channel = max_channels - 1;
1782 		break;
1783 
1784 	default:
1785 		host->max_lun = STORVSC_IDE_MAX_LUNS_PER_TARGET;
1786 		host->max_id = STORVSC_IDE_MAX_TARGETS;
1787 		host->max_channel = STORVSC_IDE_MAX_CHANNELS - 1;
1788 		break;
1789 	}
1790 	/* max cmd length */
1791 	host->max_cmd_len = STORVSC_MAX_CMD_LEN;
1792 
1793 	/*
1794 	 * set the table size based on the info we got
1795 	 * from the host.
1796 	 */
1797 	host->sg_tablesize = (stor_device->max_transfer_bytes >> PAGE_SHIFT);
1798 	/*
1799 	 * Set the number of HW queues we are supporting.
1800 	 */
1801 	if (stor_device->num_sc != 0)
1802 		host->nr_hw_queues = stor_device->num_sc + 1;
1803 
1804 	/* Register the HBA and start the scsi bus scan */
1805 	ret = scsi_add_host(host, &device->device);
1806 	if (ret != 0)
1807 		goto err_out2;
1808 
1809 	if (!dev_is_ide) {
1810 		scsi_scan_host(host);
1811 	} else {
1812 		target = (device->dev_instance.b[5] << 8 |
1813 			 device->dev_instance.b[4]);
1814 		ret = scsi_add_device(host, 0, target, 0);
1815 		if (ret)
1816 			goto err_out3;
1817 	}
1818 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
1819 	if (host->transportt == fc_transport_template) {
1820 		struct fc_rport_identifiers ids = {
1821 			.roles = FC_PORT_ROLE_FCP_DUMMY_INITIATOR,
1822 		};
1823 
1824 		fc_host_node_name(host) = stor_device->node_name;
1825 		fc_host_port_name(host) = stor_device->port_name;
1826 		stor_device->rport = fc_remote_port_add(host, 0, &ids);
1827 		if (!stor_device->rport)
1828 			goto err_out3;
1829 	}
1830 #endif
1831 	return 0;
1832 
1833 err_out3:
1834 	scsi_remove_host(host);
1835 
1836 err_out2:
1837 	/*
1838 	 * Once we have connected with the host, we would need to
1839 	 * to invoke storvsc_dev_remove() to rollback this state and
1840 	 * this call also frees up the stor_device; hence the jump around
1841 	 * err_out1 label.
1842 	 */
1843 	storvsc_dev_remove(device);
1844 	goto err_out0;
1845 
1846 err_out1:
1847 	kfree(stor_device->stor_chns);
1848 	kfree(stor_device);
1849 
1850 err_out0:
1851 	scsi_host_put(host);
1852 	return ret;
1853 }
1854 
1855 static int storvsc_remove(struct hv_device *dev)
1856 {
1857 	struct storvsc_device *stor_device = hv_get_drvdata(dev);
1858 	struct Scsi_Host *host = stor_device->host;
1859 
1860 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
1861 	if (host->transportt == fc_transport_template) {
1862 		fc_remote_port_delete(stor_device->rport);
1863 		fc_remove_host(host);
1864 	}
1865 #endif
1866 	scsi_remove_host(host);
1867 	storvsc_dev_remove(dev);
1868 	scsi_host_put(host);
1869 
1870 	return 0;
1871 }
1872 
1873 static struct hv_driver storvsc_drv = {
1874 	.name = KBUILD_MODNAME,
1875 	.id_table = id_table,
1876 	.probe = storvsc_probe,
1877 	.remove = storvsc_remove,
1878 };
1879 
1880 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
1881 static struct fc_function_template fc_transport_functions = {
1882 	.show_host_node_name = 1,
1883 	.show_host_port_name = 1,
1884 };
1885 #endif
1886 
1887 static int __init storvsc_drv_init(void)
1888 {
1889 	int ret;
1890 
1891 	/*
1892 	 * Divide the ring buffer data size (which is 1 page less
1893 	 * than the ring buffer size since that page is reserved for
1894 	 * the ring buffer indices) by the max request size (which is
1895 	 * vmbus_channel_packet_multipage_buffer + struct vstor_packet + u64)
1896 	 */
1897 	max_outstanding_req_per_channel =
1898 		((storvsc_ringbuffer_size - PAGE_SIZE) /
1899 		ALIGN(MAX_MULTIPAGE_BUFFER_PACKET +
1900 		sizeof(struct vstor_packet) + sizeof(u64) -
1901 		vmscsi_size_delta,
1902 		sizeof(u64)));
1903 
1904 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
1905 	fc_transport_template = fc_attach_transport(&fc_transport_functions);
1906 	if (!fc_transport_template)
1907 		return -ENODEV;
1908 #endif
1909 
1910 	ret = vmbus_driver_register(&storvsc_drv);
1911 
1912 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
1913 	if (ret)
1914 		fc_release_transport(fc_transport_template);
1915 #endif
1916 
1917 	return ret;
1918 }
1919 
1920 static void __exit storvsc_drv_exit(void)
1921 {
1922 	vmbus_driver_unregister(&storvsc_drv);
1923 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
1924 	fc_release_transport(fc_transport_template);
1925 #endif
1926 }
1927 
1928 MODULE_LICENSE("GPL");
1929 MODULE_DESCRIPTION("Microsoft Hyper-V virtual storage driver");
1930 module_init(storvsc_drv_init);
1931 module_exit(storvsc_drv_exit);
1932