xref: /openbmc/linux/drivers/scsi/storvsc_drv.c (revision b732539e)
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 	struct workqueue_struct *handle_error_wq;
490 	struct work_struct host_scan_work;
491 	struct Scsi_Host *host;
492 };
493 
494 struct storvsc_scan_work {
495 	struct work_struct work;
496 	struct Scsi_Host *host;
497 	u8 lun;
498 	u8 tgt_id;
499 };
500 
501 static void storvsc_device_scan(struct work_struct *work)
502 {
503 	struct storvsc_scan_work *wrk;
504 	struct scsi_device *sdev;
505 
506 	wrk = container_of(work, struct storvsc_scan_work, work);
507 
508 	sdev = scsi_device_lookup(wrk->host, 0, wrk->tgt_id, wrk->lun);
509 	if (!sdev)
510 		goto done;
511 	scsi_rescan_device(&sdev->sdev_gendev);
512 	scsi_device_put(sdev);
513 
514 done:
515 	kfree(wrk);
516 }
517 
518 static void storvsc_host_scan(struct work_struct *work)
519 {
520 	struct Scsi_Host *host;
521 	struct scsi_device *sdev;
522 	struct hv_host_device *host_device =
523 		container_of(work, struct hv_host_device, host_scan_work);
524 
525 	host = host_device->host;
526 	/*
527 	 * Before scanning the host, first check to see if any of the
528 	 * currrently known devices have been hot removed. We issue a
529 	 * "unit ready" command against all currently known devices.
530 	 * This I/O will result in an error for devices that have been
531 	 * removed. As part of handling the I/O error, we remove the device.
532 	 *
533 	 * When a LUN is added or removed, the host sends us a signal to
534 	 * scan the host. Thus we are forced to discover the LUNs that
535 	 * may have been removed this way.
536 	 */
537 	mutex_lock(&host->scan_mutex);
538 	shost_for_each_device(sdev, host)
539 		scsi_test_unit_ready(sdev, 1, 1, NULL);
540 	mutex_unlock(&host->scan_mutex);
541 	/*
542 	 * Now scan the host to discover LUNs that may have been added.
543 	 */
544 	scsi_scan_host(host);
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 	struct hv_host_device *host_dev = shost_priv(host);
926 	bool do_work = false;
927 
928 	switch (SRB_STATUS(vm_srb->srb_status)) {
929 	case SRB_STATUS_ERROR:
930 		/*
931 		 * Let upper layer deal with error when
932 		 * sense message is present.
933 		 */
934 
935 		if (vm_srb->srb_status & SRB_STATUS_AUTOSENSE_VALID)
936 			break;
937 		/*
938 		 * If there is an error; offline the device since all
939 		 * error recovery strategies would have already been
940 		 * deployed on the host side. However, if the command
941 		 * were a pass-through command deal with it appropriately.
942 		 */
943 		switch (scmnd->cmnd[0]) {
944 		case ATA_16:
945 		case ATA_12:
946 			set_host_byte(scmnd, DID_PASSTHROUGH);
947 			break;
948 		/*
949 		 * On Some Windows hosts TEST_UNIT_READY command can return
950 		 * SRB_STATUS_ERROR, let the upper level code deal with it
951 		 * based on the sense information.
952 		 */
953 		case TEST_UNIT_READY:
954 			break;
955 		default:
956 			set_host_byte(scmnd, DID_ERROR);
957 		}
958 		break;
959 	case SRB_STATUS_INVALID_LUN:
960 		set_host_byte(scmnd, DID_NO_CONNECT);
961 		do_work = true;
962 		process_err_fn = storvsc_remove_lun;
963 		break;
964 	case SRB_STATUS_ABORTED:
965 		if (vm_srb->srb_status & SRB_STATUS_AUTOSENSE_VALID &&
966 		    (asc == 0x2a) && (ascq == 0x9)) {
967 			do_work = true;
968 			process_err_fn = storvsc_device_scan;
969 			/*
970 			 * Retry the I/O that trigerred this.
971 			 */
972 			set_host_byte(scmnd, DID_REQUEUE);
973 		}
974 		break;
975 	}
976 
977 	if (!do_work)
978 		return;
979 
980 	/*
981 	 * We need to schedule work to process this error; schedule it.
982 	 */
983 	wrk = kmalloc(sizeof(struct storvsc_scan_work), GFP_ATOMIC);
984 	if (!wrk) {
985 		set_host_byte(scmnd, DID_TARGET_FAILURE);
986 		return;
987 	}
988 
989 	wrk->host = host;
990 	wrk->lun = vm_srb->lun;
991 	wrk->tgt_id = vm_srb->target_id;
992 	INIT_WORK(&wrk->work, process_err_fn);
993 	queue_work(host_dev->handle_error_wq, &wrk->work);
994 }
995 
996 
997 static void storvsc_command_completion(struct storvsc_cmd_request *cmd_request,
998 				       struct storvsc_device *stor_dev)
999 {
1000 	struct scsi_cmnd *scmnd = cmd_request->cmd;
1001 	struct scsi_sense_hdr sense_hdr;
1002 	struct vmscsi_request *vm_srb;
1003 	u32 data_transfer_length;
1004 	struct Scsi_Host *host;
1005 	u32 payload_sz = cmd_request->payload_sz;
1006 	void *payload = cmd_request->payload;
1007 
1008 	host = stor_dev->host;
1009 
1010 	vm_srb = &cmd_request->vstor_packet.vm_srb;
1011 	data_transfer_length = vm_srb->data_transfer_length;
1012 
1013 	scmnd->result = vm_srb->scsi_status;
1014 
1015 	if (scmnd->result) {
1016 		if (scsi_normalize_sense(scmnd->sense_buffer,
1017 				SCSI_SENSE_BUFFERSIZE, &sense_hdr) &&
1018 		    !(sense_hdr.sense_key == NOT_READY &&
1019 				 sense_hdr.asc == 0x03A) &&
1020 		    do_logging(STORVSC_LOGGING_ERROR))
1021 			scsi_print_sense_hdr(scmnd->device, "storvsc",
1022 					     &sense_hdr);
1023 	}
1024 
1025 	if (vm_srb->srb_status != SRB_STATUS_SUCCESS) {
1026 		storvsc_handle_error(vm_srb, scmnd, host, sense_hdr.asc,
1027 					 sense_hdr.ascq);
1028 		/*
1029 		 * The Windows driver set data_transfer_length on
1030 		 * SRB_STATUS_DATA_OVERRUN. On other errors, this value
1031 		 * is untouched.  In these cases we set it to 0.
1032 		 */
1033 		if (vm_srb->srb_status != SRB_STATUS_DATA_OVERRUN)
1034 			data_transfer_length = 0;
1035 	}
1036 
1037 	scsi_set_resid(scmnd,
1038 		cmd_request->payload->range.len - data_transfer_length);
1039 
1040 	scmnd->scsi_done(scmnd);
1041 
1042 	if (payload_sz >
1043 		sizeof(struct vmbus_channel_packet_multipage_buffer))
1044 		kfree(payload);
1045 }
1046 
1047 static void storvsc_on_io_completion(struct storvsc_device *stor_device,
1048 				  struct vstor_packet *vstor_packet,
1049 				  struct storvsc_cmd_request *request)
1050 {
1051 	struct vstor_packet *stor_pkt;
1052 	struct hv_device *device = stor_device->device;
1053 
1054 	stor_pkt = &request->vstor_packet;
1055 
1056 	/*
1057 	 * The current SCSI handling on the host side does
1058 	 * not correctly handle:
1059 	 * INQUIRY command with page code parameter set to 0x80
1060 	 * MODE_SENSE command with cmd[2] == 0x1c
1061 	 *
1062 	 * Setup srb and scsi status so this won't be fatal.
1063 	 * We do this so we can distinguish truly fatal failues
1064 	 * (srb status == 0x4) and off-line the device in that case.
1065 	 */
1066 
1067 	if ((stor_pkt->vm_srb.cdb[0] == INQUIRY) ||
1068 	   (stor_pkt->vm_srb.cdb[0] == MODE_SENSE)) {
1069 		vstor_packet->vm_srb.scsi_status = 0;
1070 		vstor_packet->vm_srb.srb_status = SRB_STATUS_SUCCESS;
1071 	}
1072 
1073 
1074 	/* Copy over the status...etc */
1075 	stor_pkt->vm_srb.scsi_status = vstor_packet->vm_srb.scsi_status;
1076 	stor_pkt->vm_srb.srb_status = vstor_packet->vm_srb.srb_status;
1077 	stor_pkt->vm_srb.sense_info_length =
1078 	vstor_packet->vm_srb.sense_info_length;
1079 
1080 	if (vstor_packet->vm_srb.scsi_status != 0 ||
1081 	    vstor_packet->vm_srb.srb_status != SRB_STATUS_SUCCESS)
1082 		storvsc_log(device, STORVSC_LOGGING_WARN,
1083 			"cmd 0x%x scsi status 0x%x srb status 0x%x\n",
1084 			stor_pkt->vm_srb.cdb[0],
1085 			vstor_packet->vm_srb.scsi_status,
1086 			vstor_packet->vm_srb.srb_status);
1087 
1088 	if ((vstor_packet->vm_srb.scsi_status & 0xFF) == 0x02) {
1089 		/* CHECK_CONDITION */
1090 		if (vstor_packet->vm_srb.srb_status &
1091 			SRB_STATUS_AUTOSENSE_VALID) {
1092 			/* autosense data available */
1093 
1094 			storvsc_log(device, STORVSC_LOGGING_WARN,
1095 				"stor pkt %p autosense data valid - len %d\n",
1096 				request, vstor_packet->vm_srb.sense_info_length);
1097 
1098 			memcpy(request->cmd->sense_buffer,
1099 			       vstor_packet->vm_srb.sense_data,
1100 			       vstor_packet->vm_srb.sense_info_length);
1101 
1102 		}
1103 	}
1104 
1105 	stor_pkt->vm_srb.data_transfer_length =
1106 	vstor_packet->vm_srb.data_transfer_length;
1107 
1108 	storvsc_command_completion(request, stor_device);
1109 
1110 	if (atomic_dec_and_test(&stor_device->num_outstanding_req) &&
1111 		stor_device->drain_notify)
1112 		wake_up(&stor_device->waiting_to_drain);
1113 
1114 
1115 }
1116 
1117 static void storvsc_on_receive(struct storvsc_device *stor_device,
1118 			     struct vstor_packet *vstor_packet,
1119 			     struct storvsc_cmd_request *request)
1120 {
1121 	struct hv_host_device *host_dev;
1122 	switch (vstor_packet->operation) {
1123 	case VSTOR_OPERATION_COMPLETE_IO:
1124 		storvsc_on_io_completion(stor_device, vstor_packet, request);
1125 		break;
1126 
1127 	case VSTOR_OPERATION_REMOVE_DEVICE:
1128 	case VSTOR_OPERATION_ENUMERATE_BUS:
1129 		host_dev = shost_priv(stor_device->host);
1130 		queue_work(
1131 			host_dev->handle_error_wq, &host_dev->host_scan_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 	const struct vmpacket_descriptor *desc;
1150 	struct hv_device *device;
1151 	struct storvsc_device *stor_device;
1152 
1153 	if (channel->primary_channel != NULL)
1154 		device = channel->primary_channel->device_obj;
1155 	else
1156 		device = channel->device_obj;
1157 
1158 	stor_device = get_in_stor_device(device);
1159 	if (!stor_device)
1160 		return;
1161 
1162 	foreach_vmbus_pkt(desc, channel) {
1163 		void *packet = hv_pkt_data(desc);
1164 		struct storvsc_cmd_request *request;
1165 
1166 		request = (struct storvsc_cmd_request *)
1167 			((unsigned long)desc->trans_id);
1168 
1169 		if (request == &stor_device->init_request ||
1170 		    request == &stor_device->reset_request) {
1171 			memcpy(&request->vstor_packet, packet,
1172 			       (sizeof(struct vstor_packet) - vmscsi_size_delta));
1173 			complete(&request->wait_event);
1174 		} else {
1175 			storvsc_on_receive(stor_device, packet, request);
1176 		}
1177 	}
1178 }
1179 
1180 static int storvsc_connect_to_vsp(struct hv_device *device, u32 ring_size,
1181 				  bool is_fc)
1182 {
1183 	struct vmstorage_channel_properties props;
1184 	int ret;
1185 
1186 	memset(&props, 0, sizeof(struct vmstorage_channel_properties));
1187 
1188 	ret = vmbus_open(device->channel,
1189 			 ring_size,
1190 			 ring_size,
1191 			 (void *)&props,
1192 			 sizeof(struct vmstorage_channel_properties),
1193 			 storvsc_on_channel_callback, device->channel);
1194 
1195 	if (ret != 0)
1196 		return ret;
1197 
1198 	ret = storvsc_channel_init(device, is_fc);
1199 
1200 	return ret;
1201 }
1202 
1203 static int storvsc_dev_remove(struct hv_device *device)
1204 {
1205 	struct storvsc_device *stor_device;
1206 
1207 	stor_device = hv_get_drvdata(device);
1208 
1209 	stor_device->destroy = true;
1210 
1211 	/* Make sure flag is set before waiting */
1212 	wmb();
1213 
1214 	/*
1215 	 * At this point, all outbound traffic should be disable. We
1216 	 * only allow inbound traffic (responses) to proceed so that
1217 	 * outstanding requests can be completed.
1218 	 */
1219 
1220 	storvsc_wait_to_drain(stor_device);
1221 
1222 	/*
1223 	 * Since we have already drained, we don't need to busy wait
1224 	 * as was done in final_release_stor_device()
1225 	 * Note that we cannot set the ext pointer to NULL until
1226 	 * we have drained - to drain the outgoing packets, we need to
1227 	 * allow incoming packets.
1228 	 */
1229 	hv_set_drvdata(device, NULL);
1230 
1231 	/* Close the channel */
1232 	vmbus_close(device->channel);
1233 
1234 	kfree(stor_device->stor_chns);
1235 	kfree(stor_device);
1236 	return 0;
1237 }
1238 
1239 static struct vmbus_channel *get_og_chn(struct storvsc_device *stor_device,
1240 					u16 q_num)
1241 {
1242 	u16 slot = 0;
1243 	u16 hash_qnum;
1244 	struct cpumask alloced_mask;
1245 	int num_channels, tgt_cpu;
1246 
1247 	if (stor_device->num_sc == 0)
1248 		return stor_device->device->channel;
1249 
1250 	/*
1251 	 * Our channel array is sparsley populated and we
1252 	 * initiated I/O on a processor/hw-q that does not
1253 	 * currently have a designated channel. Fix this.
1254 	 * The strategy is simple:
1255 	 * I. Ensure NUMA locality
1256 	 * II. Distribute evenly (best effort)
1257 	 * III. Mapping is persistent.
1258 	 */
1259 
1260 	cpumask_and(&alloced_mask, &stor_device->alloced_cpus,
1261 		    cpumask_of_node(cpu_to_node(q_num)));
1262 
1263 	num_channels = cpumask_weight(&alloced_mask);
1264 	if (num_channels == 0)
1265 		return stor_device->device->channel;
1266 
1267 	hash_qnum = q_num;
1268 	while (hash_qnum >= num_channels)
1269 		hash_qnum -= num_channels;
1270 
1271 	for_each_cpu(tgt_cpu, &alloced_mask) {
1272 		if (slot == hash_qnum)
1273 			break;
1274 		slot++;
1275 	}
1276 
1277 	stor_device->stor_chns[q_num] = stor_device->stor_chns[tgt_cpu];
1278 
1279 	return stor_device->stor_chns[q_num];
1280 }
1281 
1282 
1283 static int storvsc_do_io(struct hv_device *device,
1284 			 struct storvsc_cmd_request *request, u16 q_num)
1285 {
1286 	struct storvsc_device *stor_device;
1287 	struct vstor_packet *vstor_packet;
1288 	struct vmbus_channel *outgoing_channel;
1289 	int ret = 0;
1290 	struct cpumask alloced_mask;
1291 	int tgt_cpu;
1292 
1293 	vstor_packet = &request->vstor_packet;
1294 	stor_device = get_out_stor_device(device);
1295 
1296 	if (!stor_device)
1297 		return -ENODEV;
1298 
1299 
1300 	request->device  = device;
1301 	/*
1302 	 * Select an an appropriate channel to send the request out.
1303 	 */
1304 
1305 	if (stor_device->stor_chns[q_num] != NULL) {
1306 		outgoing_channel = stor_device->stor_chns[q_num];
1307 		if (outgoing_channel->target_cpu == smp_processor_id()) {
1308 			/*
1309 			 * Ideally, we want to pick a different channel if
1310 			 * available on the same NUMA node.
1311 			 */
1312 			cpumask_and(&alloced_mask, &stor_device->alloced_cpus,
1313 				    cpumask_of_node(cpu_to_node(q_num)));
1314 			for_each_cpu_wrap(tgt_cpu, &alloced_mask,
1315 					outgoing_channel->target_cpu + 1) {
1316 				if (tgt_cpu != outgoing_channel->target_cpu) {
1317 					outgoing_channel =
1318 					stor_device->stor_chns[tgt_cpu];
1319 					break;
1320 				}
1321 			}
1322 		}
1323 	} else {
1324 		outgoing_channel = get_og_chn(stor_device, q_num);
1325 	}
1326 
1327 
1328 	vstor_packet->flags |= REQUEST_COMPLETION_FLAG;
1329 
1330 	vstor_packet->vm_srb.length = (sizeof(struct vmscsi_request) -
1331 					vmscsi_size_delta);
1332 
1333 
1334 	vstor_packet->vm_srb.sense_info_length = sense_buffer_size;
1335 
1336 
1337 	vstor_packet->vm_srb.data_transfer_length =
1338 	request->payload->range.len;
1339 
1340 	vstor_packet->operation = VSTOR_OPERATION_EXECUTE_SRB;
1341 
1342 	if (request->payload->range.len) {
1343 
1344 		ret = vmbus_sendpacket_mpb_desc(outgoing_channel,
1345 				request->payload, request->payload_sz,
1346 				vstor_packet,
1347 				(sizeof(struct vstor_packet) -
1348 				vmscsi_size_delta),
1349 				(unsigned long)request);
1350 	} else {
1351 		ret = vmbus_sendpacket(outgoing_channel, vstor_packet,
1352 			       (sizeof(struct vstor_packet) -
1353 				vmscsi_size_delta),
1354 			       (unsigned long)request,
1355 			       VM_PKT_DATA_INBAND,
1356 			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
1357 	}
1358 
1359 	if (ret != 0)
1360 		return ret;
1361 
1362 	atomic_inc(&stor_device->num_outstanding_req);
1363 
1364 	return ret;
1365 }
1366 
1367 static int storvsc_device_alloc(struct scsi_device *sdevice)
1368 {
1369 	/*
1370 	 * Set blist flag to permit the reading of the VPD pages even when
1371 	 * the target may claim SPC-2 compliance. MSFT targets currently
1372 	 * claim SPC-2 compliance while they implement post SPC-2 features.
1373 	 * With this flag we can correctly handle WRITE_SAME_16 issues.
1374 	 *
1375 	 * Hypervisor reports SCSI_UNKNOWN type for DVD ROM device but
1376 	 * still supports REPORT LUN.
1377 	 */
1378 	sdevice->sdev_bflags = BLIST_REPORTLUN2 | BLIST_TRY_VPD_PAGES;
1379 
1380 	return 0;
1381 }
1382 
1383 static int storvsc_device_configure(struct scsi_device *sdevice)
1384 {
1385 
1386 	blk_queue_bounce_limit(sdevice->request_queue, BLK_BOUNCE_ANY);
1387 
1388 	blk_queue_rq_timeout(sdevice->request_queue, (storvsc_timeout * HZ));
1389 
1390 	/* Ensure there are no gaps in presented sgls */
1391 	blk_queue_virt_boundary(sdevice->request_queue, PAGE_SIZE - 1);
1392 
1393 	sdevice->no_write_same = 1;
1394 
1395 	/*
1396 	 * If the host is WIN8 or WIN8 R2, claim conformance to SPC-3
1397 	 * if the device is a MSFT virtual device.  If the host is
1398 	 * WIN10 or newer, allow write_same.
1399 	 */
1400 	if (!strncmp(sdevice->vendor, "Msft", 4)) {
1401 		switch (vmstor_proto_version) {
1402 		case VMSTOR_PROTO_VERSION_WIN8:
1403 		case VMSTOR_PROTO_VERSION_WIN8_1:
1404 			sdevice->scsi_level = SCSI_SPC_3;
1405 			break;
1406 		}
1407 
1408 		if (vmstor_proto_version >= VMSTOR_PROTO_VERSION_WIN10)
1409 			sdevice->no_write_same = 0;
1410 	}
1411 
1412 	return 0;
1413 }
1414 
1415 static int storvsc_get_chs(struct scsi_device *sdev, struct block_device * bdev,
1416 			   sector_t capacity, int *info)
1417 {
1418 	sector_t nsect = capacity;
1419 	sector_t cylinders = nsect;
1420 	int heads, sectors_pt;
1421 
1422 	/*
1423 	 * We are making up these values; let us keep it simple.
1424 	 */
1425 	heads = 0xff;
1426 	sectors_pt = 0x3f;      /* Sectors per track */
1427 	sector_div(cylinders, heads * sectors_pt);
1428 	if ((sector_t)(cylinders + 1) * heads * sectors_pt < nsect)
1429 		cylinders = 0xffff;
1430 
1431 	info[0] = heads;
1432 	info[1] = sectors_pt;
1433 	info[2] = (int)cylinders;
1434 
1435 	return 0;
1436 }
1437 
1438 static int storvsc_host_reset_handler(struct scsi_cmnd *scmnd)
1439 {
1440 	struct hv_host_device *host_dev = shost_priv(scmnd->device->host);
1441 	struct hv_device *device = host_dev->dev;
1442 
1443 	struct storvsc_device *stor_device;
1444 	struct storvsc_cmd_request *request;
1445 	struct vstor_packet *vstor_packet;
1446 	int ret, t;
1447 
1448 
1449 	stor_device = get_out_stor_device(device);
1450 	if (!stor_device)
1451 		return FAILED;
1452 
1453 	request = &stor_device->reset_request;
1454 	vstor_packet = &request->vstor_packet;
1455 
1456 	init_completion(&request->wait_event);
1457 
1458 	vstor_packet->operation = VSTOR_OPERATION_RESET_BUS;
1459 	vstor_packet->flags = REQUEST_COMPLETION_FLAG;
1460 	vstor_packet->vm_srb.path_id = stor_device->path_id;
1461 
1462 	ret = vmbus_sendpacket(device->channel, vstor_packet,
1463 			       (sizeof(struct vstor_packet) -
1464 				vmscsi_size_delta),
1465 			       (unsigned long)&stor_device->reset_request,
1466 			       VM_PKT_DATA_INBAND,
1467 			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
1468 	if (ret != 0)
1469 		return FAILED;
1470 
1471 	t = wait_for_completion_timeout(&request->wait_event, 5*HZ);
1472 	if (t == 0)
1473 		return TIMEOUT_ERROR;
1474 
1475 
1476 	/*
1477 	 * At this point, all outstanding requests in the adapter
1478 	 * should have been flushed out and return to us
1479 	 * There is a potential race here where the host may be in
1480 	 * the process of responding when we return from here.
1481 	 * Just wait for all in-transit packets to be accounted for
1482 	 * before we return from here.
1483 	 */
1484 	storvsc_wait_to_drain(stor_device);
1485 
1486 	return SUCCESS;
1487 }
1488 
1489 /*
1490  * The host guarantees to respond to each command, although I/O latencies might
1491  * be unbounded on Azure.  Reset the timer unconditionally to give the host a
1492  * chance to perform EH.
1493  */
1494 static enum blk_eh_timer_return storvsc_eh_timed_out(struct scsi_cmnd *scmnd)
1495 {
1496 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
1497 	if (scmnd->device->host->transportt == fc_transport_template)
1498 		return fc_eh_timed_out(scmnd);
1499 #endif
1500 	return BLK_EH_RESET_TIMER;
1501 }
1502 
1503 static bool storvsc_scsi_cmd_ok(struct scsi_cmnd *scmnd)
1504 {
1505 	bool allowed = true;
1506 	u8 scsi_op = scmnd->cmnd[0];
1507 
1508 	switch (scsi_op) {
1509 	/* the host does not handle WRITE_SAME, log accident usage */
1510 	case WRITE_SAME:
1511 	/*
1512 	 * smartd sends this command and the host does not handle
1513 	 * this. So, don't send it.
1514 	 */
1515 	case SET_WINDOW:
1516 		scmnd->result = ILLEGAL_REQUEST << 16;
1517 		allowed = false;
1518 		break;
1519 	default:
1520 		break;
1521 	}
1522 	return allowed;
1523 }
1524 
1525 static int storvsc_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *scmnd)
1526 {
1527 	int ret;
1528 	struct hv_host_device *host_dev = shost_priv(host);
1529 	struct hv_device *dev = host_dev->dev;
1530 	struct storvsc_cmd_request *cmd_request = scsi_cmd_priv(scmnd);
1531 	int i;
1532 	struct scatterlist *sgl;
1533 	unsigned int sg_count = 0;
1534 	struct vmscsi_request *vm_srb;
1535 	struct scatterlist *cur_sgl;
1536 	struct vmbus_packet_mpb_array  *payload;
1537 	u32 payload_sz;
1538 	u32 length;
1539 
1540 	if (vmstor_proto_version <= VMSTOR_PROTO_VERSION_WIN8) {
1541 		/*
1542 		 * On legacy hosts filter unimplemented commands.
1543 		 * Future hosts are expected to correctly handle
1544 		 * unsupported commands. Furthermore, it is
1545 		 * possible that some of the currently
1546 		 * unsupported commands maybe supported in
1547 		 * future versions of the host.
1548 		 */
1549 		if (!storvsc_scsi_cmd_ok(scmnd)) {
1550 			scmnd->scsi_done(scmnd);
1551 			return 0;
1552 		}
1553 	}
1554 
1555 	/* Setup the cmd request */
1556 	cmd_request->cmd = scmnd;
1557 
1558 	vm_srb = &cmd_request->vstor_packet.vm_srb;
1559 	vm_srb->win8_extension.time_out_value = 60;
1560 
1561 	vm_srb->win8_extension.srb_flags |=
1562 		SRB_FLAGS_DISABLE_SYNCH_TRANSFER;
1563 
1564 	if (scmnd->device->tagged_supported) {
1565 		vm_srb->win8_extension.srb_flags |=
1566 		(SRB_FLAGS_QUEUE_ACTION_ENABLE | SRB_FLAGS_NO_QUEUE_FREEZE);
1567 		vm_srb->win8_extension.queue_tag = SP_UNTAGGED;
1568 		vm_srb->win8_extension.queue_action = SRB_SIMPLE_TAG_REQUEST;
1569 	}
1570 
1571 	/* Build the SRB */
1572 	switch (scmnd->sc_data_direction) {
1573 	case DMA_TO_DEVICE:
1574 		vm_srb->data_in = WRITE_TYPE;
1575 		vm_srb->win8_extension.srb_flags |= SRB_FLAGS_DATA_OUT;
1576 		break;
1577 	case DMA_FROM_DEVICE:
1578 		vm_srb->data_in = READ_TYPE;
1579 		vm_srb->win8_extension.srb_flags |= SRB_FLAGS_DATA_IN;
1580 		break;
1581 	case DMA_NONE:
1582 		vm_srb->data_in = UNKNOWN_TYPE;
1583 		vm_srb->win8_extension.srb_flags |= SRB_FLAGS_NO_DATA_TRANSFER;
1584 		break;
1585 	default:
1586 		/*
1587 		 * This is DMA_BIDIRECTIONAL or something else we are never
1588 		 * supposed to see here.
1589 		 */
1590 		WARN(1, "Unexpected data direction: %d\n",
1591 		     scmnd->sc_data_direction);
1592 		return -EINVAL;
1593 	}
1594 
1595 
1596 	vm_srb->port_number = host_dev->port;
1597 	vm_srb->path_id = scmnd->device->channel;
1598 	vm_srb->target_id = scmnd->device->id;
1599 	vm_srb->lun = scmnd->device->lun;
1600 
1601 	vm_srb->cdb_length = scmnd->cmd_len;
1602 
1603 	memcpy(vm_srb->cdb, scmnd->cmnd, vm_srb->cdb_length);
1604 
1605 	sgl = (struct scatterlist *)scsi_sglist(scmnd);
1606 	sg_count = scsi_sg_count(scmnd);
1607 
1608 	length = scsi_bufflen(scmnd);
1609 	payload = (struct vmbus_packet_mpb_array *)&cmd_request->mpb;
1610 	payload_sz = sizeof(cmd_request->mpb);
1611 
1612 	if (sg_count) {
1613 		if (sg_count > MAX_PAGE_BUFFER_COUNT) {
1614 
1615 			payload_sz = (sg_count * sizeof(u64) +
1616 				      sizeof(struct vmbus_packet_mpb_array));
1617 			payload = kzalloc(payload_sz, GFP_ATOMIC);
1618 			if (!payload)
1619 				return SCSI_MLQUEUE_DEVICE_BUSY;
1620 		}
1621 
1622 		payload->range.len = length;
1623 		payload->range.offset = sgl[0].offset;
1624 
1625 		cur_sgl = sgl;
1626 		for (i = 0; i < sg_count; i++) {
1627 			payload->range.pfn_array[i] =
1628 				page_to_pfn(sg_page((cur_sgl)));
1629 			cur_sgl = sg_next(cur_sgl);
1630 		}
1631 	}
1632 
1633 	cmd_request->payload = payload;
1634 	cmd_request->payload_sz = payload_sz;
1635 
1636 	/* Invokes the vsc to start an IO */
1637 	ret = storvsc_do_io(dev, cmd_request, get_cpu());
1638 	put_cpu();
1639 
1640 	if (ret == -EAGAIN) {
1641 		if (payload_sz > sizeof(cmd_request->mpb))
1642 			kfree(payload);
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 =		2048,
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 	host_dev->host = host;
1746 
1747 
1748 	stor_device = kzalloc(sizeof(struct storvsc_device), GFP_KERNEL);
1749 	if (!stor_device) {
1750 		ret = -ENOMEM;
1751 		goto err_out0;
1752 	}
1753 
1754 	stor_device->destroy = false;
1755 	stor_device->open_sub_channel = false;
1756 	init_waitqueue_head(&stor_device->waiting_to_drain);
1757 	stor_device->device = device;
1758 	stor_device->host = host;
1759 	hv_set_drvdata(device, stor_device);
1760 
1761 	stor_device->port_number = host->host_no;
1762 	ret = storvsc_connect_to_vsp(device, storvsc_ringbuffer_size, is_fc);
1763 	if (ret)
1764 		goto err_out1;
1765 
1766 	host_dev->path = stor_device->path_id;
1767 	host_dev->target = stor_device->target_id;
1768 
1769 	switch (dev_id->driver_data) {
1770 	case SFC_GUID:
1771 		host->max_lun = STORVSC_FC_MAX_LUNS_PER_TARGET;
1772 		host->max_id = STORVSC_FC_MAX_TARGETS;
1773 		host->max_channel = STORVSC_FC_MAX_CHANNELS - 1;
1774 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
1775 		host->transportt = fc_transport_template;
1776 #endif
1777 		break;
1778 
1779 	case SCSI_GUID:
1780 		host->max_lun = max_luns_per_target;
1781 		host->max_id = max_targets;
1782 		host->max_channel = max_channels - 1;
1783 		break;
1784 
1785 	default:
1786 		host->max_lun = STORVSC_IDE_MAX_LUNS_PER_TARGET;
1787 		host->max_id = STORVSC_IDE_MAX_TARGETS;
1788 		host->max_channel = STORVSC_IDE_MAX_CHANNELS - 1;
1789 		break;
1790 	}
1791 	/* max cmd length */
1792 	host->max_cmd_len = STORVSC_MAX_CMD_LEN;
1793 
1794 	/*
1795 	 * set the table size based on the info we got
1796 	 * from the host.
1797 	 */
1798 	host->sg_tablesize = (stor_device->max_transfer_bytes >> PAGE_SHIFT);
1799 	/*
1800 	 * Set the number of HW queues we are supporting.
1801 	 */
1802 	if (stor_device->num_sc != 0)
1803 		host->nr_hw_queues = stor_device->num_sc + 1;
1804 
1805 	/*
1806 	 * Set the error handler work queue.
1807 	 */
1808 	host_dev->handle_error_wq =
1809 			alloc_ordered_workqueue("storvsc_error_wq_%d",
1810 						WQ_MEM_RECLAIM,
1811 						host->host_no);
1812 	if (!host_dev->handle_error_wq)
1813 		goto err_out2;
1814 	INIT_WORK(&host_dev->host_scan_work, storvsc_host_scan);
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_out3;
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 			goto err_out4;
1828 	}
1829 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
1830 	if (host->transportt == fc_transport_template) {
1831 		struct fc_rport_identifiers ids = {
1832 			.roles = FC_PORT_ROLE_FCP_DUMMY_INITIATOR,
1833 		};
1834 
1835 		fc_host_node_name(host) = stor_device->node_name;
1836 		fc_host_port_name(host) = stor_device->port_name;
1837 		stor_device->rport = fc_remote_port_add(host, 0, &ids);
1838 		if (!stor_device->rport) {
1839 			ret = -ENOMEM;
1840 			goto err_out4;
1841 		}
1842 	}
1843 #endif
1844 	return 0;
1845 
1846 err_out4:
1847 	scsi_remove_host(host);
1848 
1849 err_out3:
1850 	destroy_workqueue(host_dev->handle_error_wq);
1851 
1852 err_out2:
1853 	/*
1854 	 * Once we have connected with the host, we would need to
1855 	 * to invoke storvsc_dev_remove() to rollback this state and
1856 	 * this call also frees up the stor_device; hence the jump around
1857 	 * err_out1 label.
1858 	 */
1859 	storvsc_dev_remove(device);
1860 	goto err_out0;
1861 
1862 err_out1:
1863 	kfree(stor_device->stor_chns);
1864 	kfree(stor_device);
1865 
1866 err_out0:
1867 	scsi_host_put(host);
1868 	return ret;
1869 }
1870 
1871 static int storvsc_remove(struct hv_device *dev)
1872 {
1873 	struct storvsc_device *stor_device = hv_get_drvdata(dev);
1874 	struct Scsi_Host *host = stor_device->host;
1875 	struct hv_host_device *host_dev = shost_priv(host);
1876 
1877 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
1878 	if (host->transportt == fc_transport_template) {
1879 		fc_remote_port_delete(stor_device->rport);
1880 		fc_remove_host(host);
1881 	}
1882 #endif
1883 	destroy_workqueue(host_dev->handle_error_wq);
1884 	scsi_remove_host(host);
1885 	storvsc_dev_remove(dev);
1886 	scsi_host_put(host);
1887 
1888 	return 0;
1889 }
1890 
1891 static struct hv_driver storvsc_drv = {
1892 	.name = KBUILD_MODNAME,
1893 	.id_table = id_table,
1894 	.probe = storvsc_probe,
1895 	.remove = storvsc_remove,
1896 };
1897 
1898 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
1899 static struct fc_function_template fc_transport_functions = {
1900 	.show_host_node_name = 1,
1901 	.show_host_port_name = 1,
1902 };
1903 #endif
1904 
1905 static int __init storvsc_drv_init(void)
1906 {
1907 	int ret;
1908 
1909 	/*
1910 	 * Divide the ring buffer data size (which is 1 page less
1911 	 * than the ring buffer size since that page is reserved for
1912 	 * the ring buffer indices) by the max request size (which is
1913 	 * vmbus_channel_packet_multipage_buffer + struct vstor_packet + u64)
1914 	 */
1915 	max_outstanding_req_per_channel =
1916 		((storvsc_ringbuffer_size - PAGE_SIZE) /
1917 		ALIGN(MAX_MULTIPAGE_BUFFER_PACKET +
1918 		sizeof(struct vstor_packet) + sizeof(u64) -
1919 		vmscsi_size_delta,
1920 		sizeof(u64)));
1921 
1922 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
1923 	fc_transport_template = fc_attach_transport(&fc_transport_functions);
1924 	if (!fc_transport_template)
1925 		return -ENODEV;
1926 #endif
1927 
1928 	ret = vmbus_driver_register(&storvsc_drv);
1929 
1930 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
1931 	if (ret)
1932 		fc_release_transport(fc_transport_template);
1933 #endif
1934 
1935 	return ret;
1936 }
1937 
1938 static void __exit storvsc_drv_exit(void)
1939 {
1940 	vmbus_driver_unregister(&storvsc_drv);
1941 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
1942 	fc_release_transport(fc_transport_template);
1943 #endif
1944 }
1945 
1946 MODULE_LICENSE("GPL");
1947 MODULE_DESCRIPTION("Microsoft Hyper-V virtual storage driver");
1948 module_init(storvsc_drv_init);
1949 module_exit(storvsc_drv_exit);
1950