xref: /linux/drivers/scsi/storvsc_drv.c (revision e5c86679d5e864947a52fb31e45a425dea3e7fa9)
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 };
480 
481 struct hv_host_device {
482 	struct hv_device *dev;
483 	unsigned int port;
484 	unsigned char path;
485 	unsigned char target;
486 };
487 
488 struct storvsc_scan_work {
489 	struct work_struct work;
490 	struct Scsi_Host *host;
491 	u8 lun;
492 	u8 tgt_id;
493 };
494 
495 static void storvsc_device_scan(struct work_struct *work)
496 {
497 	struct storvsc_scan_work *wrk;
498 	struct scsi_device *sdev;
499 
500 	wrk = container_of(work, struct storvsc_scan_work, work);
501 
502 	sdev = scsi_device_lookup(wrk->host, 0, wrk->tgt_id, wrk->lun);
503 	if (!sdev)
504 		goto done;
505 	scsi_rescan_device(&sdev->sdev_gendev);
506 	scsi_device_put(sdev);
507 
508 done:
509 	kfree(wrk);
510 }
511 
512 static void storvsc_host_scan(struct work_struct *work)
513 {
514 	struct storvsc_scan_work *wrk;
515 	struct Scsi_Host *host;
516 	struct scsi_device *sdev;
517 
518 	wrk = container_of(work, struct storvsc_scan_work, work);
519 	host = wrk->host;
520 
521 	/*
522 	 * Before scanning the host, first check to see if any of the
523 	 * currrently known devices have been hot removed. We issue a
524 	 * "unit ready" command against all currently known devices.
525 	 * This I/O will result in an error for devices that have been
526 	 * removed. As part of handling the I/O error, we remove the device.
527 	 *
528 	 * When a LUN is added or removed, the host sends us a signal to
529 	 * scan the host. Thus we are forced to discover the LUNs that
530 	 * may have been removed this way.
531 	 */
532 	mutex_lock(&host->scan_mutex);
533 	shost_for_each_device(sdev, host)
534 		scsi_test_unit_ready(sdev, 1, 1, NULL);
535 	mutex_unlock(&host->scan_mutex);
536 	/*
537 	 * Now scan the host to discover LUNs that may have been added.
538 	 */
539 	scsi_scan_host(host);
540 
541 	kfree(wrk);
542 }
543 
544 static void storvsc_remove_lun(struct work_struct *work)
545 {
546 	struct storvsc_scan_work *wrk;
547 	struct scsi_device *sdev;
548 
549 	wrk = container_of(work, struct storvsc_scan_work, work);
550 	if (!scsi_host_get(wrk->host))
551 		goto done;
552 
553 	sdev = scsi_device_lookup(wrk->host, 0, wrk->tgt_id, wrk->lun);
554 
555 	if (sdev) {
556 		scsi_remove_device(sdev);
557 		scsi_device_put(sdev);
558 	}
559 	scsi_host_put(wrk->host);
560 
561 done:
562 	kfree(wrk);
563 }
564 
565 
566 /*
567  * We can get incoming messages from the host that are not in response to
568  * messages that we have sent out. An example of this would be messages
569  * received by the guest to notify dynamic addition/removal of LUNs. To
570  * deal with potential race conditions where the driver may be in the
571  * midst of being unloaded when we might receive an unsolicited message
572  * from the host, we have implemented a mechanism to gurantee sequential
573  * consistency:
574  *
575  * 1) Once the device is marked as being destroyed, we will fail all
576  *    outgoing messages.
577  * 2) We permit incoming messages when the device is being destroyed,
578  *    only to properly account for messages already sent out.
579  */
580 
581 static inline struct storvsc_device *get_out_stor_device(
582 					struct hv_device *device)
583 {
584 	struct storvsc_device *stor_device;
585 
586 	stor_device = hv_get_drvdata(device);
587 
588 	if (stor_device && stor_device->destroy)
589 		stor_device = NULL;
590 
591 	return stor_device;
592 }
593 
594 
595 static inline void storvsc_wait_to_drain(struct storvsc_device *dev)
596 {
597 	dev->drain_notify = true;
598 	wait_event(dev->waiting_to_drain,
599 		   atomic_read(&dev->num_outstanding_req) == 0);
600 	dev->drain_notify = false;
601 }
602 
603 static inline struct storvsc_device *get_in_stor_device(
604 					struct hv_device *device)
605 {
606 	struct storvsc_device *stor_device;
607 
608 	stor_device = hv_get_drvdata(device);
609 
610 	if (!stor_device)
611 		goto get_in_err;
612 
613 	/*
614 	 * If the device is being destroyed; allow incoming
615 	 * traffic only to cleanup outstanding requests.
616 	 */
617 
618 	if (stor_device->destroy  &&
619 		(atomic_read(&stor_device->num_outstanding_req) == 0))
620 		stor_device = NULL;
621 
622 get_in_err:
623 	return stor_device;
624 
625 }
626 
627 static void handle_sc_creation(struct vmbus_channel *new_sc)
628 {
629 	struct hv_device *device = new_sc->primary_channel->device_obj;
630 	struct storvsc_device *stor_device;
631 	struct vmstorage_channel_properties props;
632 
633 	stor_device = get_out_stor_device(device);
634 	if (!stor_device)
635 		return;
636 
637 	if (stor_device->open_sub_channel == false)
638 		return;
639 
640 	memset(&props, 0, sizeof(struct vmstorage_channel_properties));
641 
642 	vmbus_open(new_sc,
643 		   storvsc_ringbuffer_size,
644 		   storvsc_ringbuffer_size,
645 		   (void *)&props,
646 		   sizeof(struct vmstorage_channel_properties),
647 		   storvsc_on_channel_callback, new_sc);
648 
649 	if (new_sc->state == CHANNEL_OPENED_STATE) {
650 		stor_device->stor_chns[new_sc->target_cpu] = new_sc;
651 		cpumask_set_cpu(new_sc->target_cpu, &stor_device->alloced_cpus);
652 	}
653 }
654 
655 static void  handle_multichannel_storage(struct hv_device *device, int max_chns)
656 {
657 	struct storvsc_device *stor_device;
658 	int num_cpus = num_online_cpus();
659 	int num_sc;
660 	struct storvsc_cmd_request *request;
661 	struct vstor_packet *vstor_packet;
662 	int ret, t;
663 
664 	num_sc = ((max_chns > num_cpus) ? num_cpus : max_chns);
665 	stor_device = get_out_stor_device(device);
666 	if (!stor_device)
667 		return;
668 
669 	stor_device->num_sc = num_sc;
670 	request = &stor_device->init_request;
671 	vstor_packet = &request->vstor_packet;
672 
673 	stor_device->open_sub_channel = true;
674 	/*
675 	 * Establish a handler for dealing with subchannels.
676 	 */
677 	vmbus_set_sc_create_callback(device->channel, handle_sc_creation);
678 
679 	/*
680 	 * Check to see if sub-channels have already been created. This
681 	 * can happen when this driver is re-loaded after unloading.
682 	 */
683 
684 	if (vmbus_are_subchannels_present(device->channel))
685 		return;
686 
687 	stor_device->open_sub_channel = false;
688 	/*
689 	 * Request the host to create sub-channels.
690 	 */
691 	memset(request, 0, sizeof(struct storvsc_cmd_request));
692 	init_completion(&request->wait_event);
693 	vstor_packet->operation = VSTOR_OPERATION_CREATE_SUB_CHANNELS;
694 	vstor_packet->flags = REQUEST_COMPLETION_FLAG;
695 	vstor_packet->sub_channel_count = num_sc;
696 
697 	ret = vmbus_sendpacket(device->channel, vstor_packet,
698 			       (sizeof(struct vstor_packet) -
699 			       vmscsi_size_delta),
700 			       (unsigned long)request,
701 			       VM_PKT_DATA_INBAND,
702 			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
703 
704 	if (ret != 0)
705 		return;
706 
707 	t = wait_for_completion_timeout(&request->wait_event, 10*HZ);
708 	if (t == 0)
709 		return;
710 
711 	if (vstor_packet->operation != VSTOR_OPERATION_COMPLETE_IO ||
712 	    vstor_packet->status != 0)
713 		return;
714 
715 	/*
716 	 * Now that we created the sub-channels, invoke the check; this
717 	 * may trigger the callback.
718 	 */
719 	stor_device->open_sub_channel = true;
720 	vmbus_are_subchannels_present(device->channel);
721 }
722 
723 static void cache_wwn(struct storvsc_device *stor_device,
724 		      struct vstor_packet *vstor_packet)
725 {
726 	/*
727 	 * Cache the currently active port and node ww names.
728 	 */
729 	if (vstor_packet->wwn_packet.primary_active) {
730 		stor_device->node_name =
731 			wwn_to_u64(vstor_packet->wwn_packet.primary_node_wwn);
732 		stor_device->port_name =
733 			wwn_to_u64(vstor_packet->wwn_packet.primary_port_wwn);
734 	} else {
735 		stor_device->node_name =
736 			wwn_to_u64(vstor_packet->wwn_packet.secondary_node_wwn);
737 		stor_device->port_name =
738 			wwn_to_u64(vstor_packet->wwn_packet.secondary_port_wwn);
739 	}
740 }
741 
742 
743 static int storvsc_execute_vstor_op(struct hv_device *device,
744 				    struct storvsc_cmd_request *request,
745 				    bool status_check)
746 {
747 	struct vstor_packet *vstor_packet;
748 	int ret, t;
749 
750 	vstor_packet = &request->vstor_packet;
751 
752 	init_completion(&request->wait_event);
753 	vstor_packet->flags = REQUEST_COMPLETION_FLAG;
754 
755 	ret = vmbus_sendpacket(device->channel, vstor_packet,
756 			       (sizeof(struct vstor_packet) -
757 			       vmscsi_size_delta),
758 			       (unsigned long)request,
759 			       VM_PKT_DATA_INBAND,
760 			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
761 	if (ret != 0)
762 		return ret;
763 
764 	t = wait_for_completion_timeout(&request->wait_event, 5*HZ);
765 	if (t == 0)
766 		return -ETIMEDOUT;
767 
768 	if (!status_check)
769 		return ret;
770 
771 	if (vstor_packet->operation != VSTOR_OPERATION_COMPLETE_IO ||
772 	    vstor_packet->status != 0)
773 		return -EINVAL;
774 
775 	return ret;
776 }
777 
778 static int storvsc_channel_init(struct hv_device *device, bool is_fc)
779 {
780 	struct storvsc_device *stor_device;
781 	struct storvsc_cmd_request *request;
782 	struct vstor_packet *vstor_packet;
783 	int ret, i;
784 	int max_chns;
785 	bool process_sub_channels = false;
786 
787 	stor_device = get_out_stor_device(device);
788 	if (!stor_device)
789 		return -ENODEV;
790 
791 	request = &stor_device->init_request;
792 	vstor_packet = &request->vstor_packet;
793 
794 	/*
795 	 * Now, initiate the vsc/vsp initialization protocol on the open
796 	 * channel
797 	 */
798 	memset(request, 0, sizeof(struct storvsc_cmd_request));
799 	vstor_packet->operation = VSTOR_OPERATION_BEGIN_INITIALIZATION;
800 	ret = storvsc_execute_vstor_op(device, request, true);
801 	if (ret)
802 		return ret;
803 	/*
804 	 * Query host supported protocol version.
805 	 */
806 
807 	for (i = 0; i < ARRAY_SIZE(vmstor_protocols); i++) {
808 		/* reuse the packet for version range supported */
809 		memset(vstor_packet, 0, sizeof(struct vstor_packet));
810 		vstor_packet->operation =
811 			VSTOR_OPERATION_QUERY_PROTOCOL_VERSION;
812 
813 		vstor_packet->version.major_minor =
814 			vmstor_protocols[i].protocol_version;
815 
816 		/*
817 		 * The revision number is only used in Windows; set it to 0.
818 		 */
819 		vstor_packet->version.revision = 0;
820 		ret = storvsc_execute_vstor_op(device, request, false);
821 		if (ret != 0)
822 			return ret;
823 
824 		if (vstor_packet->operation != VSTOR_OPERATION_COMPLETE_IO)
825 			return -EINVAL;
826 
827 		if (vstor_packet->status == 0) {
828 			vmstor_proto_version =
829 				vmstor_protocols[i].protocol_version;
830 
831 			sense_buffer_size =
832 				vmstor_protocols[i].sense_buffer_size;
833 
834 			vmscsi_size_delta =
835 				vmstor_protocols[i].vmscsi_size_delta;
836 
837 			break;
838 		}
839 	}
840 
841 	if (vstor_packet->status != 0)
842 		return -EINVAL;
843 
844 
845 	memset(vstor_packet, 0, sizeof(struct vstor_packet));
846 	vstor_packet->operation = VSTOR_OPERATION_QUERY_PROPERTIES;
847 	ret = storvsc_execute_vstor_op(device, request, true);
848 	if (ret != 0)
849 		return ret;
850 
851 	/*
852 	 * Check to see if multi-channel support is there.
853 	 * Hosts that implement protocol version of 5.1 and above
854 	 * support multi-channel.
855 	 */
856 	max_chns = vstor_packet->storage_channel_properties.max_channel_cnt;
857 
858 	/*
859 	 * Allocate state to manage the sub-channels.
860 	 * We allocate an array based on the numbers of possible CPUs
861 	 * (Hyper-V does not support cpu online/offline).
862 	 * This Array will be sparseley populated with unique
863 	 * channels - primary + sub-channels.
864 	 * We will however populate all the slots to evenly distribute
865 	 * the load.
866 	 */
867 	stor_device->stor_chns = kzalloc(sizeof(void *) * num_possible_cpus(),
868 					 GFP_KERNEL);
869 	if (stor_device->stor_chns == NULL)
870 		return -ENOMEM;
871 
872 	stor_device->stor_chns[device->channel->target_cpu] = device->channel;
873 	cpumask_set_cpu(device->channel->target_cpu,
874 			&stor_device->alloced_cpus);
875 
876 	if (vmstor_proto_version >= VMSTOR_PROTO_VERSION_WIN8) {
877 		if (vstor_packet->storage_channel_properties.flags &
878 		    STORAGE_CHANNEL_SUPPORTS_MULTI_CHANNEL)
879 			process_sub_channels = true;
880 	}
881 	stor_device->max_transfer_bytes =
882 		vstor_packet->storage_channel_properties.max_transfer_bytes;
883 
884 	if (!is_fc)
885 		goto done;
886 
887 	/*
888 	 * For FC devices retrieve FC HBA data.
889 	 */
890 	memset(vstor_packet, 0, sizeof(struct vstor_packet));
891 	vstor_packet->operation = VSTOR_OPERATION_FCHBA_DATA;
892 	ret = storvsc_execute_vstor_op(device, request, true);
893 	if (ret != 0)
894 		return ret;
895 
896 	/*
897 	 * Cache the currently active port and node ww names.
898 	 */
899 	cache_wwn(stor_device, vstor_packet);
900 
901 done:
902 
903 	memset(vstor_packet, 0, sizeof(struct vstor_packet));
904 	vstor_packet->operation = VSTOR_OPERATION_END_INITIALIZATION;
905 	ret = storvsc_execute_vstor_op(device, request, true);
906 	if (ret != 0)
907 		return ret;
908 
909 	if (process_sub_channels)
910 		handle_multichannel_storage(device, max_chns);
911 
912 	return ret;
913 }
914 
915 static void storvsc_handle_error(struct vmscsi_request *vm_srb,
916 				struct scsi_cmnd *scmnd,
917 				struct Scsi_Host *host,
918 				u8 asc, u8 ascq)
919 {
920 	struct storvsc_scan_work *wrk;
921 	void (*process_err_fn)(struct work_struct *work);
922 	bool do_work = false;
923 
924 	switch (SRB_STATUS(vm_srb->srb_status)) {
925 	case SRB_STATUS_ERROR:
926 		/*
927 		 * Let upper layer deal with error when
928 		 * sense message is present.
929 		 */
930 
931 		if (vm_srb->srb_status & SRB_STATUS_AUTOSENSE_VALID)
932 			break;
933 		/*
934 		 * If there is an error; offline the device since all
935 		 * error recovery strategies would have already been
936 		 * deployed on the host side. However, if the command
937 		 * were a pass-through command deal with it appropriately.
938 		 */
939 		switch (scmnd->cmnd[0]) {
940 		case ATA_16:
941 		case ATA_12:
942 			set_host_byte(scmnd, DID_PASSTHROUGH);
943 			break;
944 		/*
945 		 * On Some Windows hosts TEST_UNIT_READY command can return
946 		 * SRB_STATUS_ERROR, let the upper level code deal with it
947 		 * based on the sense information.
948 		 */
949 		case TEST_UNIT_READY:
950 			break;
951 		default:
952 			set_host_byte(scmnd, DID_TARGET_FAILURE);
953 		}
954 		break;
955 	case SRB_STATUS_INVALID_LUN:
956 		do_work = true;
957 		process_err_fn = storvsc_remove_lun;
958 		break;
959 	case SRB_STATUS_ABORTED:
960 		if (vm_srb->srb_status & SRB_STATUS_AUTOSENSE_VALID &&
961 		    (asc == 0x2a) && (ascq == 0x9)) {
962 			do_work = true;
963 			process_err_fn = storvsc_device_scan;
964 			/*
965 			 * Retry the I/O that trigerred this.
966 			 */
967 			set_host_byte(scmnd, DID_REQUEUE);
968 		}
969 		break;
970 	}
971 
972 	if (!do_work)
973 		return;
974 
975 	/*
976 	 * We need to schedule work to process this error; schedule it.
977 	 */
978 	wrk = kmalloc(sizeof(struct storvsc_scan_work), GFP_ATOMIC);
979 	if (!wrk) {
980 		set_host_byte(scmnd, DID_TARGET_FAILURE);
981 		return;
982 	}
983 
984 	wrk->host = host;
985 	wrk->lun = vm_srb->lun;
986 	wrk->tgt_id = vm_srb->target_id;
987 	INIT_WORK(&wrk->work, process_err_fn);
988 	schedule_work(&wrk->work);
989 }
990 
991 
992 static void storvsc_command_completion(struct storvsc_cmd_request *cmd_request,
993 				       struct storvsc_device *stor_dev)
994 {
995 	struct scsi_cmnd *scmnd = cmd_request->cmd;
996 	struct scsi_sense_hdr sense_hdr;
997 	struct vmscsi_request *vm_srb;
998 	u32 data_transfer_length;
999 	struct Scsi_Host *host;
1000 	u32 payload_sz = cmd_request->payload_sz;
1001 	void *payload = cmd_request->payload;
1002 
1003 	host = stor_dev->host;
1004 
1005 	vm_srb = &cmd_request->vstor_packet.vm_srb;
1006 	data_transfer_length = vm_srb->data_transfer_length;
1007 
1008 	scmnd->result = vm_srb->scsi_status;
1009 
1010 	if (scmnd->result) {
1011 		if (scsi_normalize_sense(scmnd->sense_buffer,
1012 				SCSI_SENSE_BUFFERSIZE, &sense_hdr) &&
1013 		    !(sense_hdr.sense_key == NOT_READY &&
1014 				 sense_hdr.asc == 0x03A) &&
1015 		    do_logging(STORVSC_LOGGING_ERROR))
1016 			scsi_print_sense_hdr(scmnd->device, "storvsc",
1017 					     &sense_hdr);
1018 	}
1019 
1020 	if (vm_srb->srb_status != SRB_STATUS_SUCCESS) {
1021 		storvsc_handle_error(vm_srb, scmnd, host, sense_hdr.asc,
1022 					 sense_hdr.ascq);
1023 		/*
1024 		 * The Windows driver set data_transfer_length on
1025 		 * SRB_STATUS_DATA_OVERRUN. On other errors, this value
1026 		 * is untouched.  In these cases we set it to 0.
1027 		 */
1028 		if (vm_srb->srb_status != SRB_STATUS_DATA_OVERRUN)
1029 			data_transfer_length = 0;
1030 	}
1031 
1032 	scsi_set_resid(scmnd,
1033 		cmd_request->payload->range.len - data_transfer_length);
1034 
1035 	scmnd->scsi_done(scmnd);
1036 
1037 	if (payload_sz >
1038 		sizeof(struct vmbus_channel_packet_multipage_buffer))
1039 		kfree(payload);
1040 }
1041 
1042 static void storvsc_on_io_completion(struct storvsc_device *stor_device,
1043 				  struct vstor_packet *vstor_packet,
1044 				  struct storvsc_cmd_request *request)
1045 {
1046 	struct vstor_packet *stor_pkt;
1047 	struct hv_device *device = stor_device->device;
1048 
1049 	stor_pkt = &request->vstor_packet;
1050 
1051 	/*
1052 	 * The current SCSI handling on the host side does
1053 	 * not correctly handle:
1054 	 * INQUIRY command with page code parameter set to 0x80
1055 	 * MODE_SENSE command with cmd[2] == 0x1c
1056 	 *
1057 	 * Setup srb and scsi status so this won't be fatal.
1058 	 * We do this so we can distinguish truly fatal failues
1059 	 * (srb status == 0x4) and off-line the device in that case.
1060 	 */
1061 
1062 	if ((stor_pkt->vm_srb.cdb[0] == INQUIRY) ||
1063 	   (stor_pkt->vm_srb.cdb[0] == MODE_SENSE)) {
1064 		vstor_packet->vm_srb.scsi_status = 0;
1065 		vstor_packet->vm_srb.srb_status = SRB_STATUS_SUCCESS;
1066 	}
1067 
1068 
1069 	/* Copy over the status...etc */
1070 	stor_pkt->vm_srb.scsi_status = vstor_packet->vm_srb.scsi_status;
1071 	stor_pkt->vm_srb.srb_status = vstor_packet->vm_srb.srb_status;
1072 	stor_pkt->vm_srb.sense_info_length =
1073 	vstor_packet->vm_srb.sense_info_length;
1074 
1075 	if (vstor_packet->vm_srb.scsi_status != 0 ||
1076 	    vstor_packet->vm_srb.srb_status != SRB_STATUS_SUCCESS)
1077 		storvsc_log(device, STORVSC_LOGGING_WARN,
1078 			"cmd 0x%x scsi status 0x%x srb status 0x%x\n",
1079 			stor_pkt->vm_srb.cdb[0],
1080 			vstor_packet->vm_srb.scsi_status,
1081 			vstor_packet->vm_srb.srb_status);
1082 
1083 	if ((vstor_packet->vm_srb.scsi_status & 0xFF) == 0x02) {
1084 		/* CHECK_CONDITION */
1085 		if (vstor_packet->vm_srb.srb_status &
1086 			SRB_STATUS_AUTOSENSE_VALID) {
1087 			/* autosense data available */
1088 
1089 			storvsc_log(device, STORVSC_LOGGING_WARN,
1090 				"stor pkt %p autosense data valid - len %d\n",
1091 				request, vstor_packet->vm_srb.sense_info_length);
1092 
1093 			memcpy(request->cmd->sense_buffer,
1094 			       vstor_packet->vm_srb.sense_data,
1095 			       vstor_packet->vm_srb.sense_info_length);
1096 
1097 		}
1098 	}
1099 
1100 	stor_pkt->vm_srb.data_transfer_length =
1101 	vstor_packet->vm_srb.data_transfer_length;
1102 
1103 	storvsc_command_completion(request, stor_device);
1104 
1105 	if (atomic_dec_and_test(&stor_device->num_outstanding_req) &&
1106 		stor_device->drain_notify)
1107 		wake_up(&stor_device->waiting_to_drain);
1108 
1109 
1110 }
1111 
1112 static void storvsc_on_receive(struct storvsc_device *stor_device,
1113 			     struct vstor_packet *vstor_packet,
1114 			     struct storvsc_cmd_request *request)
1115 {
1116 	struct storvsc_scan_work *work;
1117 
1118 	switch (vstor_packet->operation) {
1119 	case VSTOR_OPERATION_COMPLETE_IO:
1120 		storvsc_on_io_completion(stor_device, vstor_packet, request);
1121 		break;
1122 
1123 	case VSTOR_OPERATION_REMOVE_DEVICE:
1124 	case VSTOR_OPERATION_ENUMERATE_BUS:
1125 		work = kmalloc(sizeof(struct storvsc_scan_work), GFP_ATOMIC);
1126 		if (!work)
1127 			return;
1128 
1129 		INIT_WORK(&work->work, storvsc_host_scan);
1130 		work->host = stor_device->host;
1131 		schedule_work(&work->work);
1132 		break;
1133 
1134 	case VSTOR_OPERATION_FCHBA_DATA:
1135 		cache_wwn(stor_device, vstor_packet);
1136 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
1137 		fc_host_node_name(stor_device->host) = stor_device->node_name;
1138 		fc_host_port_name(stor_device->host) = stor_device->port_name;
1139 #endif
1140 		break;
1141 	default:
1142 		break;
1143 	}
1144 }
1145 
1146 static void storvsc_on_channel_callback(void *context)
1147 {
1148 	struct vmbus_channel *channel = (struct vmbus_channel *)context;
1149 	struct hv_device *device;
1150 	struct storvsc_device *stor_device;
1151 	u32 bytes_recvd;
1152 	u64 request_id;
1153 	unsigned char packet[ALIGN(sizeof(struct vstor_packet), 8)];
1154 	struct storvsc_cmd_request *request;
1155 	int ret;
1156 
1157 	if (channel->primary_channel != NULL)
1158 		device = channel->primary_channel->device_obj;
1159 	else
1160 		device = channel->device_obj;
1161 
1162 	stor_device = get_in_stor_device(device);
1163 	if (!stor_device)
1164 		return;
1165 
1166 	do {
1167 		ret = vmbus_recvpacket(channel, packet,
1168 				       ALIGN((sizeof(struct vstor_packet) -
1169 					     vmscsi_size_delta), 8),
1170 				       &bytes_recvd, &request_id);
1171 		if (ret == 0 && bytes_recvd > 0) {
1172 
1173 			request = (struct storvsc_cmd_request *)
1174 					(unsigned long)request_id;
1175 
1176 			if ((request == &stor_device->init_request) ||
1177 			    (request == &stor_device->reset_request)) {
1178 
1179 				memcpy(&request->vstor_packet, packet,
1180 				       (sizeof(struct vstor_packet) -
1181 					vmscsi_size_delta));
1182 				complete(&request->wait_event);
1183 			} else {
1184 				storvsc_on_receive(stor_device,
1185 						(struct vstor_packet *)packet,
1186 						request);
1187 			}
1188 		} else {
1189 			break;
1190 		}
1191 	} while (1);
1192 
1193 	return;
1194 }
1195 
1196 static int storvsc_connect_to_vsp(struct hv_device *device, u32 ring_size,
1197 				  bool is_fc)
1198 {
1199 	struct vmstorage_channel_properties props;
1200 	int ret;
1201 
1202 	memset(&props, 0, sizeof(struct vmstorage_channel_properties));
1203 
1204 	ret = vmbus_open(device->channel,
1205 			 ring_size,
1206 			 ring_size,
1207 			 (void *)&props,
1208 			 sizeof(struct vmstorage_channel_properties),
1209 			 storvsc_on_channel_callback, device->channel);
1210 
1211 	if (ret != 0)
1212 		return ret;
1213 
1214 	ret = storvsc_channel_init(device, is_fc);
1215 
1216 	return ret;
1217 }
1218 
1219 static int storvsc_dev_remove(struct hv_device *device)
1220 {
1221 	struct storvsc_device *stor_device;
1222 	unsigned long flags;
1223 
1224 	stor_device = hv_get_drvdata(device);
1225 
1226 	spin_lock_irqsave(&device->channel->inbound_lock, flags);
1227 	stor_device->destroy = true;
1228 	spin_unlock_irqrestore(&device->channel->inbound_lock, flags);
1229 
1230 	/*
1231 	 * At this point, all outbound traffic should be disable. We
1232 	 * only allow inbound traffic (responses) to proceed so that
1233 	 * outstanding requests can be completed.
1234 	 */
1235 
1236 	storvsc_wait_to_drain(stor_device);
1237 
1238 	/*
1239 	 * Since we have already drained, we don't need to busy wait
1240 	 * as was done in final_release_stor_device()
1241 	 * Note that we cannot set the ext pointer to NULL until
1242 	 * we have drained - to drain the outgoing packets, we need to
1243 	 * allow incoming packets.
1244 	 */
1245 	spin_lock_irqsave(&device->channel->inbound_lock, flags);
1246 	hv_set_drvdata(device, NULL);
1247 	spin_unlock_irqrestore(&device->channel->inbound_lock, flags);
1248 
1249 	/* Close the channel */
1250 	vmbus_close(device->channel);
1251 
1252 	kfree(stor_device->stor_chns);
1253 	kfree(stor_device);
1254 	return 0;
1255 }
1256 
1257 static struct vmbus_channel *get_og_chn(struct storvsc_device *stor_device,
1258 					u16 q_num)
1259 {
1260 	u16 slot = 0;
1261 	u16 hash_qnum;
1262 	struct cpumask alloced_mask;
1263 	int num_channels, tgt_cpu;
1264 
1265 	if (stor_device->num_sc == 0)
1266 		return stor_device->device->channel;
1267 
1268 	/*
1269 	 * Our channel array is sparsley populated and we
1270 	 * initiated I/O on a processor/hw-q that does not
1271 	 * currently have a designated channel. Fix this.
1272 	 * The strategy is simple:
1273 	 * I. Ensure NUMA locality
1274 	 * II. Distribute evenly (best effort)
1275 	 * III. Mapping is persistent.
1276 	 */
1277 
1278 	cpumask_and(&alloced_mask, &stor_device->alloced_cpus,
1279 		    cpumask_of_node(cpu_to_node(q_num)));
1280 
1281 	num_channels = cpumask_weight(&alloced_mask);
1282 	if (num_channels == 0)
1283 		return stor_device->device->channel;
1284 
1285 	hash_qnum = q_num;
1286 	while (hash_qnum >= num_channels)
1287 		hash_qnum -= num_channels;
1288 
1289 	for_each_cpu(tgt_cpu, &alloced_mask) {
1290 		if (slot == hash_qnum)
1291 			break;
1292 		slot++;
1293 	}
1294 
1295 	stor_device->stor_chns[q_num] = stor_device->stor_chns[tgt_cpu];
1296 
1297 	return stor_device->stor_chns[q_num];
1298 }
1299 
1300 
1301 static int storvsc_do_io(struct hv_device *device,
1302 			 struct storvsc_cmd_request *request, u16 q_num)
1303 {
1304 	struct storvsc_device *stor_device;
1305 	struct vstor_packet *vstor_packet;
1306 	struct vmbus_channel *outgoing_channel;
1307 	int ret = 0;
1308 	struct cpumask alloced_mask;
1309 	int tgt_cpu;
1310 
1311 	vstor_packet = &request->vstor_packet;
1312 	stor_device = get_out_stor_device(device);
1313 
1314 	if (!stor_device)
1315 		return -ENODEV;
1316 
1317 
1318 	request->device  = device;
1319 	/*
1320 	 * Select an an appropriate channel to send the request out.
1321 	 */
1322 
1323 	if (stor_device->stor_chns[q_num] != NULL) {
1324 		outgoing_channel = stor_device->stor_chns[q_num];
1325 		if (outgoing_channel->target_cpu == smp_processor_id()) {
1326 			/*
1327 			 * Ideally, we want to pick a different channel if
1328 			 * available on the same NUMA node.
1329 			 */
1330 			cpumask_and(&alloced_mask, &stor_device->alloced_cpus,
1331 				    cpumask_of_node(cpu_to_node(q_num)));
1332 			for_each_cpu(tgt_cpu, &alloced_mask) {
1333 				if (tgt_cpu != outgoing_channel->target_cpu) {
1334 					outgoing_channel =
1335 					stor_device->stor_chns[tgt_cpu];
1336 					break;
1337 				}
1338 			}
1339 		}
1340 	} else {
1341 		outgoing_channel = get_og_chn(stor_device, q_num);
1342 	}
1343 
1344 
1345 	vstor_packet->flags |= REQUEST_COMPLETION_FLAG;
1346 
1347 	vstor_packet->vm_srb.length = (sizeof(struct vmscsi_request) -
1348 					vmscsi_size_delta);
1349 
1350 
1351 	vstor_packet->vm_srb.sense_info_length = sense_buffer_size;
1352 
1353 
1354 	vstor_packet->vm_srb.data_transfer_length =
1355 	request->payload->range.len;
1356 
1357 	vstor_packet->operation = VSTOR_OPERATION_EXECUTE_SRB;
1358 
1359 	if (request->payload->range.len) {
1360 
1361 		ret = vmbus_sendpacket_mpb_desc(outgoing_channel,
1362 				request->payload, request->payload_sz,
1363 				vstor_packet,
1364 				(sizeof(struct vstor_packet) -
1365 				vmscsi_size_delta),
1366 				(unsigned long)request);
1367 	} else {
1368 		ret = vmbus_sendpacket(outgoing_channel, vstor_packet,
1369 			       (sizeof(struct vstor_packet) -
1370 				vmscsi_size_delta),
1371 			       (unsigned long)request,
1372 			       VM_PKT_DATA_INBAND,
1373 			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
1374 	}
1375 
1376 	if (ret != 0)
1377 		return ret;
1378 
1379 	atomic_inc(&stor_device->num_outstanding_req);
1380 
1381 	return ret;
1382 }
1383 
1384 static int storvsc_device_alloc(struct scsi_device *sdevice)
1385 {
1386 	/*
1387 	 * Set blist flag to permit the reading of the VPD pages even when
1388 	 * the target may claim SPC-2 compliance. MSFT targets currently
1389 	 * claim SPC-2 compliance while they implement post SPC-2 features.
1390 	 * With this flag we can correctly handle WRITE_SAME_16 issues.
1391 	 *
1392 	 * Hypervisor reports SCSI_UNKNOWN type for DVD ROM device but
1393 	 * still supports REPORT LUN.
1394 	 */
1395 	sdevice->sdev_bflags = BLIST_REPORTLUN2 | BLIST_TRY_VPD_PAGES;
1396 
1397 	return 0;
1398 }
1399 
1400 static int storvsc_device_configure(struct scsi_device *sdevice)
1401 {
1402 
1403 	blk_queue_bounce_limit(sdevice->request_queue, BLK_BOUNCE_ANY);
1404 
1405 	blk_queue_rq_timeout(sdevice->request_queue, (storvsc_timeout * HZ));
1406 
1407 	/* Ensure there are no gaps in presented sgls */
1408 	blk_queue_virt_boundary(sdevice->request_queue, PAGE_SIZE - 1);
1409 
1410 	sdevice->no_write_same = 1;
1411 
1412 	/*
1413 	 * If the host is WIN8 or WIN8 R2, claim conformance to SPC-3
1414 	 * if the device is a MSFT virtual device.  If the host is
1415 	 * WIN10 or newer, allow write_same.
1416 	 */
1417 	if (!strncmp(sdevice->vendor, "Msft", 4)) {
1418 		switch (vmstor_proto_version) {
1419 		case VMSTOR_PROTO_VERSION_WIN8:
1420 		case VMSTOR_PROTO_VERSION_WIN8_1:
1421 			sdevice->scsi_level = SCSI_SPC_3;
1422 			break;
1423 		}
1424 
1425 		if (vmstor_proto_version >= VMSTOR_PROTO_VERSION_WIN10)
1426 			sdevice->no_write_same = 0;
1427 	}
1428 
1429 	return 0;
1430 }
1431 
1432 static int storvsc_get_chs(struct scsi_device *sdev, struct block_device * bdev,
1433 			   sector_t capacity, int *info)
1434 {
1435 	sector_t nsect = capacity;
1436 	sector_t cylinders = nsect;
1437 	int heads, sectors_pt;
1438 
1439 	/*
1440 	 * We are making up these values; let us keep it simple.
1441 	 */
1442 	heads = 0xff;
1443 	sectors_pt = 0x3f;      /* Sectors per track */
1444 	sector_div(cylinders, heads * sectors_pt);
1445 	if ((sector_t)(cylinders + 1) * heads * sectors_pt < nsect)
1446 		cylinders = 0xffff;
1447 
1448 	info[0] = heads;
1449 	info[1] = sectors_pt;
1450 	info[2] = (int)cylinders;
1451 
1452 	return 0;
1453 }
1454 
1455 static int storvsc_host_reset_handler(struct scsi_cmnd *scmnd)
1456 {
1457 	struct hv_host_device *host_dev = shost_priv(scmnd->device->host);
1458 	struct hv_device *device = host_dev->dev;
1459 
1460 	struct storvsc_device *stor_device;
1461 	struct storvsc_cmd_request *request;
1462 	struct vstor_packet *vstor_packet;
1463 	int ret, t;
1464 
1465 
1466 	stor_device = get_out_stor_device(device);
1467 	if (!stor_device)
1468 		return FAILED;
1469 
1470 	request = &stor_device->reset_request;
1471 	vstor_packet = &request->vstor_packet;
1472 
1473 	init_completion(&request->wait_event);
1474 
1475 	vstor_packet->operation = VSTOR_OPERATION_RESET_BUS;
1476 	vstor_packet->flags = REQUEST_COMPLETION_FLAG;
1477 	vstor_packet->vm_srb.path_id = stor_device->path_id;
1478 
1479 	ret = vmbus_sendpacket(device->channel, vstor_packet,
1480 			       (sizeof(struct vstor_packet) -
1481 				vmscsi_size_delta),
1482 			       (unsigned long)&stor_device->reset_request,
1483 			       VM_PKT_DATA_INBAND,
1484 			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
1485 	if (ret != 0)
1486 		return FAILED;
1487 
1488 	t = wait_for_completion_timeout(&request->wait_event, 5*HZ);
1489 	if (t == 0)
1490 		return TIMEOUT_ERROR;
1491 
1492 
1493 	/*
1494 	 * At this point, all outstanding requests in the adapter
1495 	 * should have been flushed out and return to us
1496 	 * There is a potential race here where the host may be in
1497 	 * the process of responding when we return from here.
1498 	 * Just wait for all in-transit packets to be accounted for
1499 	 * before we return from here.
1500 	 */
1501 	storvsc_wait_to_drain(stor_device);
1502 
1503 	return SUCCESS;
1504 }
1505 
1506 /*
1507  * The host guarantees to respond to each command, although I/O latencies might
1508  * be unbounded on Azure.  Reset the timer unconditionally to give the host a
1509  * chance to perform EH.
1510  */
1511 static enum blk_eh_timer_return storvsc_eh_timed_out(struct scsi_cmnd *scmnd)
1512 {
1513 	return BLK_EH_RESET_TIMER;
1514 }
1515 
1516 static bool storvsc_scsi_cmd_ok(struct scsi_cmnd *scmnd)
1517 {
1518 	bool allowed = true;
1519 	u8 scsi_op = scmnd->cmnd[0];
1520 
1521 	switch (scsi_op) {
1522 	/* the host does not handle WRITE_SAME, log accident usage */
1523 	case WRITE_SAME:
1524 	/*
1525 	 * smartd sends this command and the host does not handle
1526 	 * this. So, don't send it.
1527 	 */
1528 	case SET_WINDOW:
1529 		scmnd->result = ILLEGAL_REQUEST << 16;
1530 		allowed = false;
1531 		break;
1532 	default:
1533 		break;
1534 	}
1535 	return allowed;
1536 }
1537 
1538 static int storvsc_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *scmnd)
1539 {
1540 	int ret;
1541 	struct hv_host_device *host_dev = shost_priv(host);
1542 	struct hv_device *dev = host_dev->dev;
1543 	struct storvsc_cmd_request *cmd_request = scsi_cmd_priv(scmnd);
1544 	int i;
1545 	struct scatterlist *sgl;
1546 	unsigned int sg_count = 0;
1547 	struct vmscsi_request *vm_srb;
1548 	struct scatterlist *cur_sgl;
1549 	struct vmbus_packet_mpb_array  *payload;
1550 	u32 payload_sz;
1551 	u32 length;
1552 
1553 	if (vmstor_proto_version <= VMSTOR_PROTO_VERSION_WIN8) {
1554 		/*
1555 		 * On legacy hosts filter unimplemented commands.
1556 		 * Future hosts are expected to correctly handle
1557 		 * unsupported commands. Furthermore, it is
1558 		 * possible that some of the currently
1559 		 * unsupported commands maybe supported in
1560 		 * future versions of the host.
1561 		 */
1562 		if (!storvsc_scsi_cmd_ok(scmnd)) {
1563 			scmnd->scsi_done(scmnd);
1564 			return 0;
1565 		}
1566 	}
1567 
1568 	/* Setup the cmd request */
1569 	cmd_request->cmd = scmnd;
1570 
1571 	vm_srb = &cmd_request->vstor_packet.vm_srb;
1572 	vm_srb->win8_extension.time_out_value = 60;
1573 
1574 	vm_srb->win8_extension.srb_flags |=
1575 		SRB_FLAGS_DISABLE_SYNCH_TRANSFER;
1576 
1577 	if (scmnd->device->tagged_supported) {
1578 		vm_srb->win8_extension.srb_flags |=
1579 		(SRB_FLAGS_QUEUE_ACTION_ENABLE | SRB_FLAGS_NO_QUEUE_FREEZE);
1580 		vm_srb->win8_extension.queue_tag = SP_UNTAGGED;
1581 		vm_srb->win8_extension.queue_action = SRB_SIMPLE_TAG_REQUEST;
1582 	}
1583 
1584 	/* Build the SRB */
1585 	switch (scmnd->sc_data_direction) {
1586 	case DMA_TO_DEVICE:
1587 		vm_srb->data_in = WRITE_TYPE;
1588 		vm_srb->win8_extension.srb_flags |= SRB_FLAGS_DATA_OUT;
1589 		break;
1590 	case DMA_FROM_DEVICE:
1591 		vm_srb->data_in = READ_TYPE;
1592 		vm_srb->win8_extension.srb_flags |= SRB_FLAGS_DATA_IN;
1593 		break;
1594 	case DMA_NONE:
1595 		vm_srb->data_in = UNKNOWN_TYPE;
1596 		vm_srb->win8_extension.srb_flags |= SRB_FLAGS_NO_DATA_TRANSFER;
1597 		break;
1598 	default:
1599 		/*
1600 		 * This is DMA_BIDIRECTIONAL or something else we are never
1601 		 * supposed to see here.
1602 		 */
1603 		WARN(1, "Unexpected data direction: %d\n",
1604 		     scmnd->sc_data_direction);
1605 		return -EINVAL;
1606 	}
1607 
1608 
1609 	vm_srb->port_number = host_dev->port;
1610 	vm_srb->path_id = scmnd->device->channel;
1611 	vm_srb->target_id = scmnd->device->id;
1612 	vm_srb->lun = scmnd->device->lun;
1613 
1614 	vm_srb->cdb_length = scmnd->cmd_len;
1615 
1616 	memcpy(vm_srb->cdb, scmnd->cmnd, vm_srb->cdb_length);
1617 
1618 	sgl = (struct scatterlist *)scsi_sglist(scmnd);
1619 	sg_count = scsi_sg_count(scmnd);
1620 
1621 	length = scsi_bufflen(scmnd);
1622 	payload = (struct vmbus_packet_mpb_array *)&cmd_request->mpb;
1623 	payload_sz = sizeof(cmd_request->mpb);
1624 
1625 	if (sg_count) {
1626 		if (sg_count > MAX_PAGE_BUFFER_COUNT) {
1627 
1628 			payload_sz = (sg_count * sizeof(u64) +
1629 				      sizeof(struct vmbus_packet_mpb_array));
1630 			payload = kzalloc(payload_sz, GFP_ATOMIC);
1631 			if (!payload)
1632 				return SCSI_MLQUEUE_DEVICE_BUSY;
1633 		}
1634 
1635 		payload->range.len = length;
1636 		payload->range.offset = sgl[0].offset;
1637 
1638 		cur_sgl = sgl;
1639 		for (i = 0; i < sg_count; i++) {
1640 			payload->range.pfn_array[i] =
1641 				page_to_pfn(sg_page((cur_sgl)));
1642 			cur_sgl = sg_next(cur_sgl);
1643 		}
1644 	}
1645 
1646 	cmd_request->payload = payload;
1647 	cmd_request->payload_sz = payload_sz;
1648 
1649 	/* Invokes the vsc to start an IO */
1650 	ret = storvsc_do_io(dev, cmd_request, get_cpu());
1651 	put_cpu();
1652 
1653 	if (ret == -EAGAIN) {
1654 		/* no more space */
1655 		return SCSI_MLQUEUE_DEVICE_BUSY;
1656 	}
1657 
1658 	return 0;
1659 }
1660 
1661 static struct scsi_host_template scsi_driver = {
1662 	.module	=		THIS_MODULE,
1663 	.name =			"storvsc_host_t",
1664 	.cmd_size =             sizeof(struct storvsc_cmd_request),
1665 	.bios_param =		storvsc_get_chs,
1666 	.queuecommand =		storvsc_queuecommand,
1667 	.eh_host_reset_handler =	storvsc_host_reset_handler,
1668 	.proc_name =		"storvsc_host",
1669 	.eh_timed_out =		storvsc_eh_timed_out,
1670 	.slave_alloc =		storvsc_device_alloc,
1671 	.slave_configure =	storvsc_device_configure,
1672 	.cmd_per_lun =		255,
1673 	.this_id =		-1,
1674 	.use_clustering =	ENABLE_CLUSTERING,
1675 	/* Make sure we dont get a sg segment crosses a page boundary */
1676 	.dma_boundary =		PAGE_SIZE-1,
1677 	.no_write_same =	1,
1678 	.track_queue_depth =	1,
1679 };
1680 
1681 enum {
1682 	SCSI_GUID,
1683 	IDE_GUID,
1684 	SFC_GUID,
1685 };
1686 
1687 static const struct hv_vmbus_device_id id_table[] = {
1688 	/* SCSI guid */
1689 	{ HV_SCSI_GUID,
1690 	  .driver_data = SCSI_GUID
1691 	},
1692 	/* IDE guid */
1693 	{ HV_IDE_GUID,
1694 	  .driver_data = IDE_GUID
1695 	},
1696 	/* Fibre Channel GUID */
1697 	{
1698 	  HV_SYNTHFC_GUID,
1699 	  .driver_data = SFC_GUID
1700 	},
1701 	{ },
1702 };
1703 
1704 MODULE_DEVICE_TABLE(vmbus, id_table);
1705 
1706 static int storvsc_probe(struct hv_device *device,
1707 			const struct hv_vmbus_device_id *dev_id)
1708 {
1709 	int ret;
1710 	int num_cpus = num_online_cpus();
1711 	struct Scsi_Host *host;
1712 	struct hv_host_device *host_dev;
1713 	bool dev_is_ide = ((dev_id->driver_data == IDE_GUID) ? true : false);
1714 	bool is_fc = ((dev_id->driver_data == SFC_GUID) ? true : false);
1715 	int target = 0;
1716 	struct storvsc_device *stor_device;
1717 	int max_luns_per_target;
1718 	int max_targets;
1719 	int max_channels;
1720 	int max_sub_channels = 0;
1721 
1722 	/*
1723 	 * Based on the windows host we are running on,
1724 	 * set state to properly communicate with the host.
1725 	 */
1726 
1727 	if (vmbus_proto_version < VERSION_WIN8) {
1728 		max_luns_per_target = STORVSC_IDE_MAX_LUNS_PER_TARGET;
1729 		max_targets = STORVSC_IDE_MAX_TARGETS;
1730 		max_channels = STORVSC_IDE_MAX_CHANNELS;
1731 	} else {
1732 		max_luns_per_target = STORVSC_MAX_LUNS_PER_TARGET;
1733 		max_targets = STORVSC_MAX_TARGETS;
1734 		max_channels = STORVSC_MAX_CHANNELS;
1735 		/*
1736 		 * On Windows8 and above, we support sub-channels for storage.
1737 		 * The number of sub-channels offerred is based on the number of
1738 		 * VCPUs in the guest.
1739 		 */
1740 		max_sub_channels = (num_cpus / storvsc_vcpus_per_sub_channel);
1741 	}
1742 
1743 	scsi_driver.can_queue = (max_outstanding_req_per_channel *
1744 				 (max_sub_channels + 1));
1745 
1746 	host = scsi_host_alloc(&scsi_driver,
1747 			       sizeof(struct hv_host_device));
1748 	if (!host)
1749 		return -ENOMEM;
1750 
1751 	host_dev = shost_priv(host);
1752 	memset(host_dev, 0, sizeof(struct hv_host_device));
1753 
1754 	host_dev->port = host->host_no;
1755 	host_dev->dev = device;
1756 
1757 
1758 	stor_device = kzalloc(sizeof(struct storvsc_device), GFP_KERNEL);
1759 	if (!stor_device) {
1760 		ret = -ENOMEM;
1761 		goto err_out0;
1762 	}
1763 
1764 	stor_device->destroy = false;
1765 	stor_device->open_sub_channel = false;
1766 	init_waitqueue_head(&stor_device->waiting_to_drain);
1767 	stor_device->device = device;
1768 	stor_device->host = host;
1769 	hv_set_drvdata(device, stor_device);
1770 
1771 	stor_device->port_number = host->host_no;
1772 	ret = storvsc_connect_to_vsp(device, storvsc_ringbuffer_size, is_fc);
1773 	if (ret)
1774 		goto err_out1;
1775 
1776 	host_dev->path = stor_device->path_id;
1777 	host_dev->target = stor_device->target_id;
1778 
1779 	switch (dev_id->driver_data) {
1780 	case SFC_GUID:
1781 		host->max_lun = STORVSC_FC_MAX_LUNS_PER_TARGET;
1782 		host->max_id = STORVSC_FC_MAX_TARGETS;
1783 		host->max_channel = STORVSC_FC_MAX_CHANNELS - 1;
1784 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
1785 		host->transportt = fc_transport_template;
1786 #endif
1787 		break;
1788 
1789 	case SCSI_GUID:
1790 		host->max_lun = max_luns_per_target;
1791 		host->max_id = max_targets;
1792 		host->max_channel = max_channels - 1;
1793 		break;
1794 
1795 	default:
1796 		host->max_lun = STORVSC_IDE_MAX_LUNS_PER_TARGET;
1797 		host->max_id = STORVSC_IDE_MAX_TARGETS;
1798 		host->max_channel = STORVSC_IDE_MAX_CHANNELS - 1;
1799 		break;
1800 	}
1801 	/* max cmd length */
1802 	host->max_cmd_len = STORVSC_MAX_CMD_LEN;
1803 
1804 	/*
1805 	 * set the table size based on the info we got
1806 	 * from the host.
1807 	 */
1808 	host->sg_tablesize = (stor_device->max_transfer_bytes >> PAGE_SHIFT);
1809 	/*
1810 	 * Set the number of HW queues we are supporting.
1811 	 */
1812 	if (stor_device->num_sc != 0)
1813 		host->nr_hw_queues = stor_device->num_sc + 1;
1814 
1815 	/* Register the HBA and start the scsi bus scan */
1816 	ret = scsi_add_host(host, &device->device);
1817 	if (ret != 0)
1818 		goto err_out2;
1819 
1820 	if (!dev_is_ide) {
1821 		scsi_scan_host(host);
1822 	} else {
1823 		target = (device->dev_instance.b[5] << 8 |
1824 			 device->dev_instance.b[4]);
1825 		ret = scsi_add_device(host, 0, target, 0);
1826 		if (ret) {
1827 			scsi_remove_host(host);
1828 			goto err_out2;
1829 		}
1830 	}
1831 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
1832 	if (host->transportt == fc_transport_template) {
1833 		fc_host_node_name(host) = stor_device->node_name;
1834 		fc_host_port_name(host) = stor_device->port_name;
1835 	}
1836 #endif
1837 	return 0;
1838 
1839 err_out2:
1840 	/*
1841 	 * Once we have connected with the host, we would need to
1842 	 * to invoke storvsc_dev_remove() to rollback this state and
1843 	 * this call also frees up the stor_device; hence the jump around
1844 	 * err_out1 label.
1845 	 */
1846 	storvsc_dev_remove(device);
1847 	goto err_out0;
1848 
1849 err_out1:
1850 	kfree(stor_device->stor_chns);
1851 	kfree(stor_device);
1852 
1853 err_out0:
1854 	scsi_host_put(host);
1855 	return ret;
1856 }
1857 
1858 static int storvsc_remove(struct hv_device *dev)
1859 {
1860 	struct storvsc_device *stor_device = hv_get_drvdata(dev);
1861 	struct Scsi_Host *host = stor_device->host;
1862 
1863 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
1864 	if (host->transportt == fc_transport_template)
1865 		fc_remove_host(host);
1866 #endif
1867 	scsi_remove_host(host);
1868 	storvsc_dev_remove(dev);
1869 	scsi_host_put(host);
1870 
1871 	return 0;
1872 }
1873 
1874 static struct hv_driver storvsc_drv = {
1875 	.name = KBUILD_MODNAME,
1876 	.id_table = id_table,
1877 	.probe = storvsc_probe,
1878 	.remove = storvsc_remove,
1879 };
1880 
1881 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
1882 static struct fc_function_template fc_transport_functions = {
1883 	.show_host_node_name = 1,
1884 	.show_host_port_name = 1,
1885 };
1886 #endif
1887 
1888 static int __init storvsc_drv_init(void)
1889 {
1890 	int ret;
1891 
1892 	/*
1893 	 * Divide the ring buffer data size (which is 1 page less
1894 	 * than the ring buffer size since that page is reserved for
1895 	 * the ring buffer indices) by the max request size (which is
1896 	 * vmbus_channel_packet_multipage_buffer + struct vstor_packet + u64)
1897 	 */
1898 	max_outstanding_req_per_channel =
1899 		((storvsc_ringbuffer_size - PAGE_SIZE) /
1900 		ALIGN(MAX_MULTIPAGE_BUFFER_PACKET +
1901 		sizeof(struct vstor_packet) + sizeof(u64) -
1902 		vmscsi_size_delta,
1903 		sizeof(u64)));
1904 
1905 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
1906 	fc_transport_template = fc_attach_transport(&fc_transport_functions);
1907 	if (!fc_transport_template)
1908 		return -ENODEV;
1909 #endif
1910 
1911 	ret = vmbus_driver_register(&storvsc_drv);
1912 
1913 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
1914 	if (ret)
1915 		fc_release_transport(fc_transport_template);
1916 #endif
1917 
1918 	return ret;
1919 }
1920 
1921 static void __exit storvsc_drv_exit(void)
1922 {
1923 	vmbus_driver_unregister(&storvsc_drv);
1924 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
1925 	fc_release_transport(fc_transport_template);
1926 #endif
1927 }
1928 
1929 MODULE_LICENSE("GPL");
1930 MODULE_DESCRIPTION("Microsoft Hyper-V virtual storage driver");
1931 module_init(storvsc_drv_init);
1932 module_exit(storvsc_drv_exit);
1933