xref: /linux/drivers/scsi/storvsc_drv.c (revision 54b0a2011dfcd2e3fe2c28062694fbbe3eb377a3)
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 static int ring_avail_percent_lowater = 10;
400 module_param(ring_avail_percent_lowater, int, S_IRUGO);
401 MODULE_PARM_DESC(ring_avail_percent_lowater,
402 		"Select a channel if available ring size > this in percent");
403 
404 /*
405  * Timeout in seconds for all devices managed by this driver.
406  */
407 static int storvsc_timeout = 180;
408 
409 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
410 static struct scsi_transport_template *fc_transport_template;
411 #endif
412 
413 static void storvsc_on_channel_callback(void *context);
414 
415 #define STORVSC_MAX_LUNS_PER_TARGET			255
416 #define STORVSC_MAX_TARGETS				2
417 #define STORVSC_MAX_CHANNELS				8
418 
419 #define STORVSC_FC_MAX_LUNS_PER_TARGET			255
420 #define STORVSC_FC_MAX_TARGETS				128
421 #define STORVSC_FC_MAX_CHANNELS				8
422 
423 #define STORVSC_IDE_MAX_LUNS_PER_TARGET			64
424 #define STORVSC_IDE_MAX_TARGETS				1
425 #define STORVSC_IDE_MAX_CHANNELS			1
426 
427 struct storvsc_cmd_request {
428 	struct scsi_cmnd *cmd;
429 
430 	struct hv_device *device;
431 
432 	/* Synchronize the request/response if needed */
433 	struct completion wait_event;
434 
435 	struct vmbus_channel_packet_multipage_buffer mpb;
436 	struct vmbus_packet_mpb_array *payload;
437 	u32 payload_sz;
438 
439 	struct vstor_packet vstor_packet;
440 };
441 
442 
443 /* A storvsc device is a device object that contains a vmbus channel */
444 struct storvsc_device {
445 	struct hv_device *device;
446 
447 	bool	 destroy;
448 	bool	 drain_notify;
449 	bool	 open_sub_channel;
450 	atomic_t num_outstanding_req;
451 	struct Scsi_Host *host;
452 
453 	wait_queue_head_t waiting_to_drain;
454 
455 	/*
456 	 * Each unique Port/Path/Target represents 1 channel ie scsi
457 	 * controller. In reality, the pathid, targetid is always 0
458 	 * and the port is set by us
459 	 */
460 	unsigned int port_number;
461 	unsigned char path_id;
462 	unsigned char target_id;
463 
464 	/*
465 	 * Max I/O, the device can support.
466 	 */
467 	u32   max_transfer_bytes;
468 	/*
469 	 * Number of sub-channels we will open.
470 	 */
471 	u16 num_sc;
472 	struct vmbus_channel **stor_chns;
473 	/*
474 	 * Mask of CPUs bound to subchannels.
475 	 */
476 	struct cpumask alloced_cpus;
477 	/* Used for vsc/vsp channel reset process */
478 	struct storvsc_cmd_request init_request;
479 	struct storvsc_cmd_request reset_request;
480 	/*
481 	 * Currently active port and node names for FC devices.
482 	 */
483 	u64 node_name;
484 	u64 port_name;
485 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
486 	struct fc_rport *rport;
487 #endif
488 };
489 
490 struct hv_host_device {
491 	struct hv_device *dev;
492 	unsigned int port;
493 	unsigned char path;
494 	unsigned char target;
495 	struct workqueue_struct *handle_error_wq;
496 	struct work_struct host_scan_work;
497 	struct Scsi_Host *host;
498 };
499 
500 struct storvsc_scan_work {
501 	struct work_struct work;
502 	struct Scsi_Host *host;
503 	u8 lun;
504 	u8 tgt_id;
505 };
506 
507 static void storvsc_device_scan(struct work_struct *work)
508 {
509 	struct storvsc_scan_work *wrk;
510 	struct scsi_device *sdev;
511 
512 	wrk = container_of(work, struct storvsc_scan_work, work);
513 
514 	sdev = scsi_device_lookup(wrk->host, 0, wrk->tgt_id, wrk->lun);
515 	if (!sdev)
516 		goto done;
517 	scsi_rescan_device(&sdev->sdev_gendev);
518 	scsi_device_put(sdev);
519 
520 done:
521 	kfree(wrk);
522 }
523 
524 static void storvsc_host_scan(struct work_struct *work)
525 {
526 	struct Scsi_Host *host;
527 	struct scsi_device *sdev;
528 	struct hv_host_device *host_device =
529 		container_of(work, struct hv_host_device, host_scan_work);
530 
531 	host = host_device->host;
532 	/*
533 	 * Before scanning the host, first check to see if any of the
534 	 * currrently known devices have been hot removed. We issue a
535 	 * "unit ready" command against all currently known devices.
536 	 * This I/O will result in an error for devices that have been
537 	 * removed. As part of handling the I/O error, we remove the device.
538 	 *
539 	 * When a LUN is added or removed, the host sends us a signal to
540 	 * scan the host. Thus we are forced to discover the LUNs that
541 	 * may have been removed this way.
542 	 */
543 	mutex_lock(&host->scan_mutex);
544 	shost_for_each_device(sdev, host)
545 		scsi_test_unit_ready(sdev, 1, 1, NULL);
546 	mutex_unlock(&host->scan_mutex);
547 	/*
548 	 * Now scan the host to discover LUNs that may have been added.
549 	 */
550 	scsi_scan_host(host);
551 }
552 
553 static void storvsc_remove_lun(struct work_struct *work)
554 {
555 	struct storvsc_scan_work *wrk;
556 	struct scsi_device *sdev;
557 
558 	wrk = container_of(work, struct storvsc_scan_work, work);
559 	if (!scsi_host_get(wrk->host))
560 		goto done;
561 
562 	sdev = scsi_device_lookup(wrk->host, 0, wrk->tgt_id, wrk->lun);
563 
564 	if (sdev) {
565 		scsi_remove_device(sdev);
566 		scsi_device_put(sdev);
567 	}
568 	scsi_host_put(wrk->host);
569 
570 done:
571 	kfree(wrk);
572 }
573 
574 
575 /*
576  * We can get incoming messages from the host that are not in response to
577  * messages that we have sent out. An example of this would be messages
578  * received by the guest to notify dynamic addition/removal of LUNs. To
579  * deal with potential race conditions where the driver may be in the
580  * midst of being unloaded when we might receive an unsolicited message
581  * from the host, we have implemented a mechanism to gurantee sequential
582  * consistency:
583  *
584  * 1) Once the device is marked as being destroyed, we will fail all
585  *    outgoing messages.
586  * 2) We permit incoming messages when the device is being destroyed,
587  *    only to properly account for messages already sent out.
588  */
589 
590 static inline struct storvsc_device *get_out_stor_device(
591 					struct hv_device *device)
592 {
593 	struct storvsc_device *stor_device;
594 
595 	stor_device = hv_get_drvdata(device);
596 
597 	if (stor_device && stor_device->destroy)
598 		stor_device = NULL;
599 
600 	return stor_device;
601 }
602 
603 
604 static inline void storvsc_wait_to_drain(struct storvsc_device *dev)
605 {
606 	dev->drain_notify = true;
607 	wait_event(dev->waiting_to_drain,
608 		   atomic_read(&dev->num_outstanding_req) == 0);
609 	dev->drain_notify = false;
610 }
611 
612 static inline struct storvsc_device *get_in_stor_device(
613 					struct hv_device *device)
614 {
615 	struct storvsc_device *stor_device;
616 
617 	stor_device = hv_get_drvdata(device);
618 
619 	if (!stor_device)
620 		goto get_in_err;
621 
622 	/*
623 	 * If the device is being destroyed; allow incoming
624 	 * traffic only to cleanup outstanding requests.
625 	 */
626 
627 	if (stor_device->destroy  &&
628 		(atomic_read(&stor_device->num_outstanding_req) == 0))
629 		stor_device = NULL;
630 
631 get_in_err:
632 	return stor_device;
633 
634 }
635 
636 static void handle_sc_creation(struct vmbus_channel *new_sc)
637 {
638 	struct hv_device *device = new_sc->primary_channel->device_obj;
639 	struct storvsc_device *stor_device;
640 	struct vmstorage_channel_properties props;
641 
642 	stor_device = get_out_stor_device(device);
643 	if (!stor_device)
644 		return;
645 
646 	if (stor_device->open_sub_channel == false)
647 		return;
648 
649 	memset(&props, 0, sizeof(struct vmstorage_channel_properties));
650 
651 	vmbus_open(new_sc,
652 		   storvsc_ringbuffer_size,
653 		   storvsc_ringbuffer_size,
654 		   (void *)&props,
655 		   sizeof(struct vmstorage_channel_properties),
656 		   storvsc_on_channel_callback, new_sc);
657 
658 	if (new_sc->state == CHANNEL_OPENED_STATE) {
659 		stor_device->stor_chns[new_sc->target_cpu] = new_sc;
660 		cpumask_set_cpu(new_sc->target_cpu, &stor_device->alloced_cpus);
661 	}
662 }
663 
664 static void  handle_multichannel_storage(struct hv_device *device, int max_chns)
665 {
666 	struct storvsc_device *stor_device;
667 	int num_cpus = num_online_cpus();
668 	int num_sc;
669 	struct storvsc_cmd_request *request;
670 	struct vstor_packet *vstor_packet;
671 	int ret, t;
672 
673 	num_sc = ((max_chns > num_cpus) ? num_cpus : max_chns);
674 	stor_device = get_out_stor_device(device);
675 	if (!stor_device)
676 		return;
677 
678 	stor_device->num_sc = num_sc;
679 	request = &stor_device->init_request;
680 	vstor_packet = &request->vstor_packet;
681 
682 	stor_device->open_sub_channel = true;
683 	/*
684 	 * Establish a handler for dealing with subchannels.
685 	 */
686 	vmbus_set_sc_create_callback(device->channel, handle_sc_creation);
687 
688 	/*
689 	 * Check to see if sub-channels have already been created. This
690 	 * can happen when this driver is re-loaded after unloading.
691 	 */
692 
693 	if (vmbus_are_subchannels_present(device->channel))
694 		return;
695 
696 	stor_device->open_sub_channel = false;
697 	/*
698 	 * Request the host to create sub-channels.
699 	 */
700 	memset(request, 0, sizeof(struct storvsc_cmd_request));
701 	init_completion(&request->wait_event);
702 	vstor_packet->operation = VSTOR_OPERATION_CREATE_SUB_CHANNELS;
703 	vstor_packet->flags = REQUEST_COMPLETION_FLAG;
704 	vstor_packet->sub_channel_count = num_sc;
705 
706 	ret = vmbus_sendpacket(device->channel, vstor_packet,
707 			       (sizeof(struct vstor_packet) -
708 			       vmscsi_size_delta),
709 			       (unsigned long)request,
710 			       VM_PKT_DATA_INBAND,
711 			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
712 
713 	if (ret != 0)
714 		return;
715 
716 	t = wait_for_completion_timeout(&request->wait_event, 10*HZ);
717 	if (t == 0)
718 		return;
719 
720 	if (vstor_packet->operation != VSTOR_OPERATION_COMPLETE_IO ||
721 	    vstor_packet->status != 0)
722 		return;
723 
724 	/*
725 	 * Now that we created the sub-channels, invoke the check; this
726 	 * may trigger the callback.
727 	 */
728 	stor_device->open_sub_channel = true;
729 	vmbus_are_subchannels_present(device->channel);
730 }
731 
732 static void cache_wwn(struct storvsc_device *stor_device,
733 		      struct vstor_packet *vstor_packet)
734 {
735 	/*
736 	 * Cache the currently active port and node ww names.
737 	 */
738 	if (vstor_packet->wwn_packet.primary_active) {
739 		stor_device->node_name =
740 			wwn_to_u64(vstor_packet->wwn_packet.primary_node_wwn);
741 		stor_device->port_name =
742 			wwn_to_u64(vstor_packet->wwn_packet.primary_port_wwn);
743 	} else {
744 		stor_device->node_name =
745 			wwn_to_u64(vstor_packet->wwn_packet.secondary_node_wwn);
746 		stor_device->port_name =
747 			wwn_to_u64(vstor_packet->wwn_packet.secondary_port_wwn);
748 	}
749 }
750 
751 
752 static int storvsc_execute_vstor_op(struct hv_device *device,
753 				    struct storvsc_cmd_request *request,
754 				    bool status_check)
755 {
756 	struct vstor_packet *vstor_packet;
757 	int ret, t;
758 
759 	vstor_packet = &request->vstor_packet;
760 
761 	init_completion(&request->wait_event);
762 	vstor_packet->flags = REQUEST_COMPLETION_FLAG;
763 
764 	ret = vmbus_sendpacket(device->channel, vstor_packet,
765 			       (sizeof(struct vstor_packet) -
766 			       vmscsi_size_delta),
767 			       (unsigned long)request,
768 			       VM_PKT_DATA_INBAND,
769 			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
770 	if (ret != 0)
771 		return ret;
772 
773 	t = wait_for_completion_timeout(&request->wait_event, 5*HZ);
774 	if (t == 0)
775 		return -ETIMEDOUT;
776 
777 	if (!status_check)
778 		return ret;
779 
780 	if (vstor_packet->operation != VSTOR_OPERATION_COMPLETE_IO ||
781 	    vstor_packet->status != 0)
782 		return -EINVAL;
783 
784 	return ret;
785 }
786 
787 static int storvsc_channel_init(struct hv_device *device, bool is_fc)
788 {
789 	struct storvsc_device *stor_device;
790 	struct storvsc_cmd_request *request;
791 	struct vstor_packet *vstor_packet;
792 	int ret, i;
793 	int max_chns;
794 	bool process_sub_channels = false;
795 
796 	stor_device = get_out_stor_device(device);
797 	if (!stor_device)
798 		return -ENODEV;
799 
800 	request = &stor_device->init_request;
801 	vstor_packet = &request->vstor_packet;
802 
803 	/*
804 	 * Now, initiate the vsc/vsp initialization protocol on the open
805 	 * channel
806 	 */
807 	memset(request, 0, sizeof(struct storvsc_cmd_request));
808 	vstor_packet->operation = VSTOR_OPERATION_BEGIN_INITIALIZATION;
809 	ret = storvsc_execute_vstor_op(device, request, true);
810 	if (ret)
811 		return ret;
812 	/*
813 	 * Query host supported protocol version.
814 	 */
815 
816 	for (i = 0; i < ARRAY_SIZE(vmstor_protocols); i++) {
817 		/* reuse the packet for version range supported */
818 		memset(vstor_packet, 0, sizeof(struct vstor_packet));
819 		vstor_packet->operation =
820 			VSTOR_OPERATION_QUERY_PROTOCOL_VERSION;
821 
822 		vstor_packet->version.major_minor =
823 			vmstor_protocols[i].protocol_version;
824 
825 		/*
826 		 * The revision number is only used in Windows; set it to 0.
827 		 */
828 		vstor_packet->version.revision = 0;
829 		ret = storvsc_execute_vstor_op(device, request, false);
830 		if (ret != 0)
831 			return ret;
832 
833 		if (vstor_packet->operation != VSTOR_OPERATION_COMPLETE_IO)
834 			return -EINVAL;
835 
836 		if (vstor_packet->status == 0) {
837 			vmstor_proto_version =
838 				vmstor_protocols[i].protocol_version;
839 
840 			sense_buffer_size =
841 				vmstor_protocols[i].sense_buffer_size;
842 
843 			vmscsi_size_delta =
844 				vmstor_protocols[i].vmscsi_size_delta;
845 
846 			break;
847 		}
848 	}
849 
850 	if (vstor_packet->status != 0)
851 		return -EINVAL;
852 
853 
854 	memset(vstor_packet, 0, sizeof(struct vstor_packet));
855 	vstor_packet->operation = VSTOR_OPERATION_QUERY_PROPERTIES;
856 	ret = storvsc_execute_vstor_op(device, request, true);
857 	if (ret != 0)
858 		return ret;
859 
860 	/*
861 	 * Check to see if multi-channel support is there.
862 	 * Hosts that implement protocol version of 5.1 and above
863 	 * support multi-channel.
864 	 */
865 	max_chns = vstor_packet->storage_channel_properties.max_channel_cnt;
866 
867 	/*
868 	 * Allocate state to manage the sub-channels.
869 	 * We allocate an array based on the numbers of possible CPUs
870 	 * (Hyper-V does not support cpu online/offline).
871 	 * This Array will be sparseley populated with unique
872 	 * channels - primary + sub-channels.
873 	 * We will however populate all the slots to evenly distribute
874 	 * the load.
875 	 */
876 	stor_device->stor_chns = kcalloc(num_possible_cpus(), sizeof(void *),
877 					 GFP_KERNEL);
878 	if (stor_device->stor_chns == NULL)
879 		return -ENOMEM;
880 
881 	stor_device->stor_chns[device->channel->target_cpu] = device->channel;
882 	cpumask_set_cpu(device->channel->target_cpu,
883 			&stor_device->alloced_cpus);
884 
885 	if (vmstor_proto_version >= VMSTOR_PROTO_VERSION_WIN8) {
886 		if (vstor_packet->storage_channel_properties.flags &
887 		    STORAGE_CHANNEL_SUPPORTS_MULTI_CHANNEL)
888 			process_sub_channels = true;
889 	}
890 	stor_device->max_transfer_bytes =
891 		vstor_packet->storage_channel_properties.max_transfer_bytes;
892 
893 	if (!is_fc)
894 		goto done;
895 
896 	/*
897 	 * For FC devices retrieve FC HBA data.
898 	 */
899 	memset(vstor_packet, 0, sizeof(struct vstor_packet));
900 	vstor_packet->operation = VSTOR_OPERATION_FCHBA_DATA;
901 	ret = storvsc_execute_vstor_op(device, request, true);
902 	if (ret != 0)
903 		return ret;
904 
905 	/*
906 	 * Cache the currently active port and node ww names.
907 	 */
908 	cache_wwn(stor_device, vstor_packet);
909 
910 done:
911 
912 	memset(vstor_packet, 0, sizeof(struct vstor_packet));
913 	vstor_packet->operation = VSTOR_OPERATION_END_INITIALIZATION;
914 	ret = storvsc_execute_vstor_op(device, request, true);
915 	if (ret != 0)
916 		return ret;
917 
918 	if (process_sub_channels)
919 		handle_multichannel_storage(device, max_chns);
920 
921 	return ret;
922 }
923 
924 static void storvsc_handle_error(struct vmscsi_request *vm_srb,
925 				struct scsi_cmnd *scmnd,
926 				struct Scsi_Host *host,
927 				u8 asc, u8 ascq)
928 {
929 	struct storvsc_scan_work *wrk;
930 	void (*process_err_fn)(struct work_struct *work);
931 	struct hv_host_device *host_dev = shost_priv(host);
932 	bool do_work = false;
933 
934 	switch (SRB_STATUS(vm_srb->srb_status)) {
935 	case SRB_STATUS_ERROR:
936 		/*
937 		 * Let upper layer deal with error when
938 		 * sense message is present.
939 		 */
940 
941 		if (vm_srb->srb_status & SRB_STATUS_AUTOSENSE_VALID)
942 			break;
943 		/*
944 		 * If there is an error; offline the device since all
945 		 * error recovery strategies would have already been
946 		 * deployed on the host side. However, if the command
947 		 * were a pass-through command deal with it appropriately.
948 		 */
949 		switch (scmnd->cmnd[0]) {
950 		case ATA_16:
951 		case ATA_12:
952 			set_host_byte(scmnd, DID_PASSTHROUGH);
953 			break;
954 		/*
955 		 * On Some Windows hosts TEST_UNIT_READY command can return
956 		 * SRB_STATUS_ERROR, let the upper level code deal with it
957 		 * based on the sense information.
958 		 */
959 		case TEST_UNIT_READY:
960 			break;
961 		default:
962 			set_host_byte(scmnd, DID_ERROR);
963 		}
964 		break;
965 	case SRB_STATUS_INVALID_LUN:
966 		set_host_byte(scmnd, DID_NO_CONNECT);
967 		do_work = true;
968 		process_err_fn = storvsc_remove_lun;
969 		break;
970 	case SRB_STATUS_ABORTED:
971 		if (vm_srb->srb_status & SRB_STATUS_AUTOSENSE_VALID &&
972 		    (asc == 0x2a) && (ascq == 0x9)) {
973 			do_work = true;
974 			process_err_fn = storvsc_device_scan;
975 			/*
976 			 * Retry the I/O that trigerred this.
977 			 */
978 			set_host_byte(scmnd, DID_REQUEUE);
979 		}
980 		break;
981 	}
982 
983 	if (!do_work)
984 		return;
985 
986 	/*
987 	 * We need to schedule work to process this error; schedule it.
988 	 */
989 	wrk = kmalloc(sizeof(struct storvsc_scan_work), GFP_ATOMIC);
990 	if (!wrk) {
991 		set_host_byte(scmnd, DID_TARGET_FAILURE);
992 		return;
993 	}
994 
995 	wrk->host = host;
996 	wrk->lun = vm_srb->lun;
997 	wrk->tgt_id = vm_srb->target_id;
998 	INIT_WORK(&wrk->work, process_err_fn);
999 	queue_work(host_dev->handle_error_wq, &wrk->work);
1000 }
1001 
1002 
1003 static void storvsc_command_completion(struct storvsc_cmd_request *cmd_request,
1004 				       struct storvsc_device *stor_dev)
1005 {
1006 	struct scsi_cmnd *scmnd = cmd_request->cmd;
1007 	struct scsi_sense_hdr sense_hdr;
1008 	struct vmscsi_request *vm_srb;
1009 	u32 data_transfer_length;
1010 	struct Scsi_Host *host;
1011 	u32 payload_sz = cmd_request->payload_sz;
1012 	void *payload = cmd_request->payload;
1013 
1014 	host = stor_dev->host;
1015 
1016 	vm_srb = &cmd_request->vstor_packet.vm_srb;
1017 	data_transfer_length = vm_srb->data_transfer_length;
1018 
1019 	scmnd->result = vm_srb->scsi_status;
1020 
1021 	if (scmnd->result) {
1022 		if (scsi_normalize_sense(scmnd->sense_buffer,
1023 				SCSI_SENSE_BUFFERSIZE, &sense_hdr) &&
1024 		    !(sense_hdr.sense_key == NOT_READY &&
1025 				 sense_hdr.asc == 0x03A) &&
1026 		    do_logging(STORVSC_LOGGING_ERROR))
1027 			scsi_print_sense_hdr(scmnd->device, "storvsc",
1028 					     &sense_hdr);
1029 	}
1030 
1031 	if (vm_srb->srb_status != SRB_STATUS_SUCCESS) {
1032 		storvsc_handle_error(vm_srb, scmnd, host, sense_hdr.asc,
1033 					 sense_hdr.ascq);
1034 		/*
1035 		 * The Windows driver set data_transfer_length on
1036 		 * SRB_STATUS_DATA_OVERRUN. On other errors, this value
1037 		 * is untouched.  In these cases we set it to 0.
1038 		 */
1039 		if (vm_srb->srb_status != SRB_STATUS_DATA_OVERRUN)
1040 			data_transfer_length = 0;
1041 	}
1042 
1043 	scsi_set_resid(scmnd,
1044 		cmd_request->payload->range.len - data_transfer_length);
1045 
1046 	scmnd->scsi_done(scmnd);
1047 
1048 	if (payload_sz >
1049 		sizeof(struct vmbus_channel_packet_multipage_buffer))
1050 		kfree(payload);
1051 }
1052 
1053 static void storvsc_on_io_completion(struct storvsc_device *stor_device,
1054 				  struct vstor_packet *vstor_packet,
1055 				  struct storvsc_cmd_request *request)
1056 {
1057 	struct vstor_packet *stor_pkt;
1058 	struct hv_device *device = stor_device->device;
1059 
1060 	stor_pkt = &request->vstor_packet;
1061 
1062 	/*
1063 	 * The current SCSI handling on the host side does
1064 	 * not correctly handle:
1065 	 * INQUIRY command with page code parameter set to 0x80
1066 	 * MODE_SENSE command with cmd[2] == 0x1c
1067 	 *
1068 	 * Setup srb and scsi status so this won't be fatal.
1069 	 * We do this so we can distinguish truly fatal failues
1070 	 * (srb status == 0x4) and off-line the device in that case.
1071 	 */
1072 
1073 	if ((stor_pkt->vm_srb.cdb[0] == INQUIRY) ||
1074 	   (stor_pkt->vm_srb.cdb[0] == MODE_SENSE)) {
1075 		vstor_packet->vm_srb.scsi_status = 0;
1076 		vstor_packet->vm_srb.srb_status = SRB_STATUS_SUCCESS;
1077 	}
1078 
1079 
1080 	/* Copy over the status...etc */
1081 	stor_pkt->vm_srb.scsi_status = vstor_packet->vm_srb.scsi_status;
1082 	stor_pkt->vm_srb.srb_status = vstor_packet->vm_srb.srb_status;
1083 	stor_pkt->vm_srb.sense_info_length =
1084 	vstor_packet->vm_srb.sense_info_length;
1085 
1086 	if (vstor_packet->vm_srb.scsi_status != 0 ||
1087 	    vstor_packet->vm_srb.srb_status != SRB_STATUS_SUCCESS)
1088 		storvsc_log(device, STORVSC_LOGGING_WARN,
1089 			"cmd 0x%x scsi status 0x%x srb status 0x%x\n",
1090 			stor_pkt->vm_srb.cdb[0],
1091 			vstor_packet->vm_srb.scsi_status,
1092 			vstor_packet->vm_srb.srb_status);
1093 
1094 	if ((vstor_packet->vm_srb.scsi_status & 0xFF) == 0x02) {
1095 		/* CHECK_CONDITION */
1096 		if (vstor_packet->vm_srb.srb_status &
1097 			SRB_STATUS_AUTOSENSE_VALID) {
1098 			/* autosense data available */
1099 
1100 			storvsc_log(device, STORVSC_LOGGING_WARN,
1101 				"stor pkt %p autosense data valid - len %d\n",
1102 				request, vstor_packet->vm_srb.sense_info_length);
1103 
1104 			memcpy(request->cmd->sense_buffer,
1105 			       vstor_packet->vm_srb.sense_data,
1106 			       vstor_packet->vm_srb.sense_info_length);
1107 
1108 		}
1109 	}
1110 
1111 	stor_pkt->vm_srb.data_transfer_length =
1112 	vstor_packet->vm_srb.data_transfer_length;
1113 
1114 	storvsc_command_completion(request, stor_device);
1115 
1116 	if (atomic_dec_and_test(&stor_device->num_outstanding_req) &&
1117 		stor_device->drain_notify)
1118 		wake_up(&stor_device->waiting_to_drain);
1119 
1120 
1121 }
1122 
1123 static void storvsc_on_receive(struct storvsc_device *stor_device,
1124 			     struct vstor_packet *vstor_packet,
1125 			     struct storvsc_cmd_request *request)
1126 {
1127 	struct hv_host_device *host_dev;
1128 	switch (vstor_packet->operation) {
1129 	case VSTOR_OPERATION_COMPLETE_IO:
1130 		storvsc_on_io_completion(stor_device, vstor_packet, request);
1131 		break;
1132 
1133 	case VSTOR_OPERATION_REMOVE_DEVICE:
1134 	case VSTOR_OPERATION_ENUMERATE_BUS:
1135 		host_dev = shost_priv(stor_device->host);
1136 		queue_work(
1137 			host_dev->handle_error_wq, &host_dev->host_scan_work);
1138 		break;
1139 
1140 	case VSTOR_OPERATION_FCHBA_DATA:
1141 		cache_wwn(stor_device, vstor_packet);
1142 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
1143 		fc_host_node_name(stor_device->host) = stor_device->node_name;
1144 		fc_host_port_name(stor_device->host) = stor_device->port_name;
1145 #endif
1146 		break;
1147 	default:
1148 		break;
1149 	}
1150 }
1151 
1152 static void storvsc_on_channel_callback(void *context)
1153 {
1154 	struct vmbus_channel *channel = (struct vmbus_channel *)context;
1155 	const struct vmpacket_descriptor *desc;
1156 	struct hv_device *device;
1157 	struct storvsc_device *stor_device;
1158 
1159 	if (channel->primary_channel != NULL)
1160 		device = channel->primary_channel->device_obj;
1161 	else
1162 		device = channel->device_obj;
1163 
1164 	stor_device = get_in_stor_device(device);
1165 	if (!stor_device)
1166 		return;
1167 
1168 	foreach_vmbus_pkt(desc, channel) {
1169 		void *packet = hv_pkt_data(desc);
1170 		struct storvsc_cmd_request *request;
1171 
1172 		request = (struct storvsc_cmd_request *)
1173 			((unsigned long)desc->trans_id);
1174 
1175 		if (request == &stor_device->init_request ||
1176 		    request == &stor_device->reset_request) {
1177 			memcpy(&request->vstor_packet, packet,
1178 			       (sizeof(struct vstor_packet) - vmscsi_size_delta));
1179 			complete(&request->wait_event);
1180 		} else {
1181 			storvsc_on_receive(stor_device, packet, request);
1182 		}
1183 	}
1184 }
1185 
1186 static int storvsc_connect_to_vsp(struct hv_device *device, u32 ring_size,
1187 				  bool is_fc)
1188 {
1189 	struct vmstorage_channel_properties props;
1190 	int ret;
1191 
1192 	memset(&props, 0, sizeof(struct vmstorage_channel_properties));
1193 
1194 	ret = vmbus_open(device->channel,
1195 			 ring_size,
1196 			 ring_size,
1197 			 (void *)&props,
1198 			 sizeof(struct vmstorage_channel_properties),
1199 			 storvsc_on_channel_callback, device->channel);
1200 
1201 	if (ret != 0)
1202 		return ret;
1203 
1204 	ret = storvsc_channel_init(device, is_fc);
1205 
1206 	return ret;
1207 }
1208 
1209 static int storvsc_dev_remove(struct hv_device *device)
1210 {
1211 	struct storvsc_device *stor_device;
1212 
1213 	stor_device = hv_get_drvdata(device);
1214 
1215 	stor_device->destroy = true;
1216 
1217 	/* Make sure flag is set before waiting */
1218 	wmb();
1219 
1220 	/*
1221 	 * At this point, all outbound traffic should be disable. We
1222 	 * only allow inbound traffic (responses) to proceed so that
1223 	 * outstanding requests can be completed.
1224 	 */
1225 
1226 	storvsc_wait_to_drain(stor_device);
1227 
1228 	/*
1229 	 * Since we have already drained, we don't need to busy wait
1230 	 * as was done in final_release_stor_device()
1231 	 * Note that we cannot set the ext pointer to NULL until
1232 	 * we have drained - to drain the outgoing packets, we need to
1233 	 * allow incoming packets.
1234 	 */
1235 	hv_set_drvdata(device, NULL);
1236 
1237 	/* Close the channel */
1238 	vmbus_close(device->channel);
1239 
1240 	kfree(stor_device->stor_chns);
1241 	kfree(stor_device);
1242 	return 0;
1243 }
1244 
1245 static struct vmbus_channel *get_og_chn(struct storvsc_device *stor_device,
1246 					u16 q_num)
1247 {
1248 	u16 slot = 0;
1249 	u16 hash_qnum;
1250 	const struct cpumask *node_mask;
1251 	int num_channels, tgt_cpu;
1252 
1253 	if (stor_device->num_sc == 0)
1254 		return stor_device->device->channel;
1255 
1256 	/*
1257 	 * Our channel array is sparsley populated and we
1258 	 * initiated I/O on a processor/hw-q that does not
1259 	 * currently have a designated channel. Fix this.
1260 	 * The strategy is simple:
1261 	 * I. Ensure NUMA locality
1262 	 * II. Distribute evenly (best effort)
1263 	 * III. Mapping is persistent.
1264 	 */
1265 
1266 	node_mask = cpumask_of_node(cpu_to_node(q_num));
1267 
1268 	num_channels = 0;
1269 	for_each_cpu(tgt_cpu, &stor_device->alloced_cpus) {
1270 		if (cpumask_test_cpu(tgt_cpu, node_mask))
1271 			num_channels++;
1272 	}
1273 	if (num_channels == 0)
1274 		return stor_device->device->channel;
1275 
1276 	hash_qnum = q_num;
1277 	while (hash_qnum >= num_channels)
1278 		hash_qnum -= num_channels;
1279 
1280 	for_each_cpu(tgt_cpu, &stor_device->alloced_cpus) {
1281 		if (!cpumask_test_cpu(tgt_cpu, node_mask))
1282 			continue;
1283 		if (slot == hash_qnum)
1284 			break;
1285 		slot++;
1286 	}
1287 
1288 	stor_device->stor_chns[q_num] = stor_device->stor_chns[tgt_cpu];
1289 
1290 	return stor_device->stor_chns[q_num];
1291 }
1292 
1293 
1294 static int storvsc_do_io(struct hv_device *device,
1295 			 struct storvsc_cmd_request *request, u16 q_num)
1296 {
1297 	struct storvsc_device *stor_device;
1298 	struct vstor_packet *vstor_packet;
1299 	struct vmbus_channel *outgoing_channel, *channel;
1300 	int ret = 0;
1301 	const struct cpumask *node_mask;
1302 	int tgt_cpu;
1303 
1304 	vstor_packet = &request->vstor_packet;
1305 	stor_device = get_out_stor_device(device);
1306 
1307 	if (!stor_device)
1308 		return -ENODEV;
1309 
1310 
1311 	request->device  = device;
1312 	/*
1313 	 * Select an an appropriate channel to send the request out.
1314 	 */
1315 	if (stor_device->stor_chns[q_num] != NULL) {
1316 		outgoing_channel = stor_device->stor_chns[q_num];
1317 		if (outgoing_channel->target_cpu == q_num) {
1318 			/*
1319 			 * Ideally, we want to pick a different channel if
1320 			 * available on the same NUMA node.
1321 			 */
1322 			node_mask = cpumask_of_node(cpu_to_node(q_num));
1323 			for_each_cpu_wrap(tgt_cpu,
1324 				 &stor_device->alloced_cpus, q_num + 1) {
1325 				if (!cpumask_test_cpu(tgt_cpu, node_mask))
1326 					continue;
1327 				if (tgt_cpu == q_num)
1328 					continue;
1329 				channel = stor_device->stor_chns[tgt_cpu];
1330 				if (hv_get_avail_to_write_percent(
1331 							&channel->outbound)
1332 						> ring_avail_percent_lowater) {
1333 					outgoing_channel = channel;
1334 					goto found_channel;
1335 				}
1336 			}
1337 
1338 			/*
1339 			 * All the other channels on the same NUMA node are
1340 			 * busy. Try to use the channel on the current CPU
1341 			 */
1342 			if (hv_get_avail_to_write_percent(
1343 						&outgoing_channel->outbound)
1344 					> ring_avail_percent_lowater)
1345 				goto found_channel;
1346 
1347 			/*
1348 			 * If we reach here, all the channels on the current
1349 			 * NUMA node are busy. Try to find a channel in
1350 			 * other NUMA nodes
1351 			 */
1352 			for_each_cpu(tgt_cpu, &stor_device->alloced_cpus) {
1353 				if (cpumask_test_cpu(tgt_cpu, node_mask))
1354 					continue;
1355 				channel = stor_device->stor_chns[tgt_cpu];
1356 				if (hv_get_avail_to_write_percent(
1357 							&channel->outbound)
1358 						> ring_avail_percent_lowater) {
1359 					outgoing_channel = channel;
1360 					goto found_channel;
1361 				}
1362 			}
1363 		}
1364 	} else {
1365 		outgoing_channel = get_og_chn(stor_device, q_num);
1366 	}
1367 
1368 found_channel:
1369 	vstor_packet->flags |= REQUEST_COMPLETION_FLAG;
1370 
1371 	vstor_packet->vm_srb.length = (sizeof(struct vmscsi_request) -
1372 					vmscsi_size_delta);
1373 
1374 
1375 	vstor_packet->vm_srb.sense_info_length = sense_buffer_size;
1376 
1377 
1378 	vstor_packet->vm_srb.data_transfer_length =
1379 	request->payload->range.len;
1380 
1381 	vstor_packet->operation = VSTOR_OPERATION_EXECUTE_SRB;
1382 
1383 	if (request->payload->range.len) {
1384 
1385 		ret = vmbus_sendpacket_mpb_desc(outgoing_channel,
1386 				request->payload, request->payload_sz,
1387 				vstor_packet,
1388 				(sizeof(struct vstor_packet) -
1389 				vmscsi_size_delta),
1390 				(unsigned long)request);
1391 	} else {
1392 		ret = vmbus_sendpacket(outgoing_channel, vstor_packet,
1393 			       (sizeof(struct vstor_packet) -
1394 				vmscsi_size_delta),
1395 			       (unsigned long)request,
1396 			       VM_PKT_DATA_INBAND,
1397 			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
1398 	}
1399 
1400 	if (ret != 0)
1401 		return ret;
1402 
1403 	atomic_inc(&stor_device->num_outstanding_req);
1404 
1405 	return ret;
1406 }
1407 
1408 static int storvsc_device_alloc(struct scsi_device *sdevice)
1409 {
1410 	/*
1411 	 * Set blist flag to permit the reading of the VPD pages even when
1412 	 * the target may claim SPC-2 compliance. MSFT targets currently
1413 	 * claim SPC-2 compliance while they implement post SPC-2 features.
1414 	 * With this flag we can correctly handle WRITE_SAME_16 issues.
1415 	 *
1416 	 * Hypervisor reports SCSI_UNKNOWN type for DVD ROM device but
1417 	 * still supports REPORT LUN.
1418 	 */
1419 	sdevice->sdev_bflags = BLIST_REPORTLUN2 | BLIST_TRY_VPD_PAGES;
1420 
1421 	return 0;
1422 }
1423 
1424 static int storvsc_device_configure(struct scsi_device *sdevice)
1425 {
1426 	blk_queue_rq_timeout(sdevice->request_queue, (storvsc_timeout * HZ));
1427 
1428 	/* Ensure there are no gaps in presented sgls */
1429 	blk_queue_virt_boundary(sdevice->request_queue, PAGE_SIZE - 1);
1430 
1431 	sdevice->no_write_same = 1;
1432 
1433 	/*
1434 	 * If the host is WIN8 or WIN8 R2, claim conformance to SPC-3
1435 	 * if the device is a MSFT virtual device.  If the host is
1436 	 * WIN10 or newer, allow write_same.
1437 	 */
1438 	if (!strncmp(sdevice->vendor, "Msft", 4)) {
1439 		switch (vmstor_proto_version) {
1440 		case VMSTOR_PROTO_VERSION_WIN8:
1441 		case VMSTOR_PROTO_VERSION_WIN8_1:
1442 			sdevice->scsi_level = SCSI_SPC_3;
1443 			break;
1444 		}
1445 
1446 		if (vmstor_proto_version >= VMSTOR_PROTO_VERSION_WIN10)
1447 			sdevice->no_write_same = 0;
1448 	}
1449 
1450 	return 0;
1451 }
1452 
1453 static int storvsc_get_chs(struct scsi_device *sdev, struct block_device * bdev,
1454 			   sector_t capacity, int *info)
1455 {
1456 	sector_t nsect = capacity;
1457 	sector_t cylinders = nsect;
1458 	int heads, sectors_pt;
1459 
1460 	/*
1461 	 * We are making up these values; let us keep it simple.
1462 	 */
1463 	heads = 0xff;
1464 	sectors_pt = 0x3f;      /* Sectors per track */
1465 	sector_div(cylinders, heads * sectors_pt);
1466 	if ((sector_t)(cylinders + 1) * heads * sectors_pt < nsect)
1467 		cylinders = 0xffff;
1468 
1469 	info[0] = heads;
1470 	info[1] = sectors_pt;
1471 	info[2] = (int)cylinders;
1472 
1473 	return 0;
1474 }
1475 
1476 static int storvsc_host_reset_handler(struct scsi_cmnd *scmnd)
1477 {
1478 	struct hv_host_device *host_dev = shost_priv(scmnd->device->host);
1479 	struct hv_device *device = host_dev->dev;
1480 
1481 	struct storvsc_device *stor_device;
1482 	struct storvsc_cmd_request *request;
1483 	struct vstor_packet *vstor_packet;
1484 	int ret, t;
1485 
1486 
1487 	stor_device = get_out_stor_device(device);
1488 	if (!stor_device)
1489 		return FAILED;
1490 
1491 	request = &stor_device->reset_request;
1492 	vstor_packet = &request->vstor_packet;
1493 
1494 	init_completion(&request->wait_event);
1495 
1496 	vstor_packet->operation = VSTOR_OPERATION_RESET_BUS;
1497 	vstor_packet->flags = REQUEST_COMPLETION_FLAG;
1498 	vstor_packet->vm_srb.path_id = stor_device->path_id;
1499 
1500 	ret = vmbus_sendpacket(device->channel, vstor_packet,
1501 			       (sizeof(struct vstor_packet) -
1502 				vmscsi_size_delta),
1503 			       (unsigned long)&stor_device->reset_request,
1504 			       VM_PKT_DATA_INBAND,
1505 			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
1506 	if (ret != 0)
1507 		return FAILED;
1508 
1509 	t = wait_for_completion_timeout(&request->wait_event, 5*HZ);
1510 	if (t == 0)
1511 		return TIMEOUT_ERROR;
1512 
1513 
1514 	/*
1515 	 * At this point, all outstanding requests in the adapter
1516 	 * should have been flushed out and return to us
1517 	 * There is a potential race here where the host may be in
1518 	 * the process of responding when we return from here.
1519 	 * Just wait for all in-transit packets to be accounted for
1520 	 * before we return from here.
1521 	 */
1522 	storvsc_wait_to_drain(stor_device);
1523 
1524 	return SUCCESS;
1525 }
1526 
1527 /*
1528  * The host guarantees to respond to each command, although I/O latencies might
1529  * be unbounded on Azure.  Reset the timer unconditionally to give the host a
1530  * chance to perform EH.
1531  */
1532 static enum blk_eh_timer_return storvsc_eh_timed_out(struct scsi_cmnd *scmnd)
1533 {
1534 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
1535 	if (scmnd->device->host->transportt == fc_transport_template)
1536 		return fc_eh_timed_out(scmnd);
1537 #endif
1538 	return BLK_EH_RESET_TIMER;
1539 }
1540 
1541 static bool storvsc_scsi_cmd_ok(struct scsi_cmnd *scmnd)
1542 {
1543 	bool allowed = true;
1544 	u8 scsi_op = scmnd->cmnd[0];
1545 
1546 	switch (scsi_op) {
1547 	/* the host does not handle WRITE_SAME, log accident usage */
1548 	case WRITE_SAME:
1549 	/*
1550 	 * smartd sends this command and the host does not handle
1551 	 * this. So, don't send it.
1552 	 */
1553 	case SET_WINDOW:
1554 		scmnd->result = ILLEGAL_REQUEST << 16;
1555 		allowed = false;
1556 		break;
1557 	default:
1558 		break;
1559 	}
1560 	return allowed;
1561 }
1562 
1563 static int storvsc_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *scmnd)
1564 {
1565 	int ret;
1566 	struct hv_host_device *host_dev = shost_priv(host);
1567 	struct hv_device *dev = host_dev->dev;
1568 	struct storvsc_cmd_request *cmd_request = scsi_cmd_priv(scmnd);
1569 	int i;
1570 	struct scatterlist *sgl;
1571 	unsigned int sg_count = 0;
1572 	struct vmscsi_request *vm_srb;
1573 	struct scatterlist *cur_sgl;
1574 	struct vmbus_packet_mpb_array  *payload;
1575 	u32 payload_sz;
1576 	u32 length;
1577 
1578 	if (vmstor_proto_version <= VMSTOR_PROTO_VERSION_WIN8) {
1579 		/*
1580 		 * On legacy hosts filter unimplemented commands.
1581 		 * Future hosts are expected to correctly handle
1582 		 * unsupported commands. Furthermore, it is
1583 		 * possible that some of the currently
1584 		 * unsupported commands maybe supported in
1585 		 * future versions of the host.
1586 		 */
1587 		if (!storvsc_scsi_cmd_ok(scmnd)) {
1588 			scmnd->scsi_done(scmnd);
1589 			return 0;
1590 		}
1591 	}
1592 
1593 	/* Setup the cmd request */
1594 	cmd_request->cmd = scmnd;
1595 
1596 	vm_srb = &cmd_request->vstor_packet.vm_srb;
1597 	vm_srb->win8_extension.time_out_value = 60;
1598 
1599 	vm_srb->win8_extension.srb_flags |=
1600 		SRB_FLAGS_DISABLE_SYNCH_TRANSFER;
1601 
1602 	if (scmnd->device->tagged_supported) {
1603 		vm_srb->win8_extension.srb_flags |=
1604 		(SRB_FLAGS_QUEUE_ACTION_ENABLE | SRB_FLAGS_NO_QUEUE_FREEZE);
1605 		vm_srb->win8_extension.queue_tag = SP_UNTAGGED;
1606 		vm_srb->win8_extension.queue_action = SRB_SIMPLE_TAG_REQUEST;
1607 	}
1608 
1609 	/* Build the SRB */
1610 	switch (scmnd->sc_data_direction) {
1611 	case DMA_TO_DEVICE:
1612 		vm_srb->data_in = WRITE_TYPE;
1613 		vm_srb->win8_extension.srb_flags |= SRB_FLAGS_DATA_OUT;
1614 		break;
1615 	case DMA_FROM_DEVICE:
1616 		vm_srb->data_in = READ_TYPE;
1617 		vm_srb->win8_extension.srb_flags |= SRB_FLAGS_DATA_IN;
1618 		break;
1619 	case DMA_NONE:
1620 		vm_srb->data_in = UNKNOWN_TYPE;
1621 		vm_srb->win8_extension.srb_flags |= SRB_FLAGS_NO_DATA_TRANSFER;
1622 		break;
1623 	default:
1624 		/*
1625 		 * This is DMA_BIDIRECTIONAL or something else we are never
1626 		 * supposed to see here.
1627 		 */
1628 		WARN(1, "Unexpected data direction: %d\n",
1629 		     scmnd->sc_data_direction);
1630 		return -EINVAL;
1631 	}
1632 
1633 
1634 	vm_srb->port_number = host_dev->port;
1635 	vm_srb->path_id = scmnd->device->channel;
1636 	vm_srb->target_id = scmnd->device->id;
1637 	vm_srb->lun = scmnd->device->lun;
1638 
1639 	vm_srb->cdb_length = scmnd->cmd_len;
1640 
1641 	memcpy(vm_srb->cdb, scmnd->cmnd, vm_srb->cdb_length);
1642 
1643 	sgl = (struct scatterlist *)scsi_sglist(scmnd);
1644 	sg_count = scsi_sg_count(scmnd);
1645 
1646 	length = scsi_bufflen(scmnd);
1647 	payload = (struct vmbus_packet_mpb_array *)&cmd_request->mpb;
1648 	payload_sz = sizeof(cmd_request->mpb);
1649 
1650 	if (sg_count) {
1651 		if (sg_count > MAX_PAGE_BUFFER_COUNT) {
1652 
1653 			payload_sz = (sg_count * sizeof(u64) +
1654 				      sizeof(struct vmbus_packet_mpb_array));
1655 			payload = kzalloc(payload_sz, GFP_ATOMIC);
1656 			if (!payload)
1657 				return SCSI_MLQUEUE_DEVICE_BUSY;
1658 		}
1659 
1660 		payload->range.len = length;
1661 		payload->range.offset = sgl[0].offset;
1662 
1663 		cur_sgl = sgl;
1664 		for (i = 0; i < sg_count; i++) {
1665 			payload->range.pfn_array[i] =
1666 				page_to_pfn(sg_page((cur_sgl)));
1667 			cur_sgl = sg_next(cur_sgl);
1668 		}
1669 	}
1670 
1671 	cmd_request->payload = payload;
1672 	cmd_request->payload_sz = payload_sz;
1673 
1674 	/* Invokes the vsc to start an IO */
1675 	ret = storvsc_do_io(dev, cmd_request, get_cpu());
1676 	put_cpu();
1677 
1678 	if (ret == -EAGAIN) {
1679 		if (payload_sz > sizeof(cmd_request->mpb))
1680 			kfree(payload);
1681 		/* no more space */
1682 		return SCSI_MLQUEUE_DEVICE_BUSY;
1683 	}
1684 
1685 	return 0;
1686 }
1687 
1688 static struct scsi_host_template scsi_driver = {
1689 	.module	=		THIS_MODULE,
1690 	.name =			"storvsc_host_t",
1691 	.cmd_size =             sizeof(struct storvsc_cmd_request),
1692 	.bios_param =		storvsc_get_chs,
1693 	.queuecommand =		storvsc_queuecommand,
1694 	.eh_host_reset_handler =	storvsc_host_reset_handler,
1695 	.proc_name =		"storvsc_host",
1696 	.eh_timed_out =		storvsc_eh_timed_out,
1697 	.slave_alloc =		storvsc_device_alloc,
1698 	.slave_configure =	storvsc_device_configure,
1699 	.cmd_per_lun =		2048,
1700 	.this_id =		-1,
1701 	.use_clustering =	ENABLE_CLUSTERING,
1702 	/* Make sure we dont get a sg segment crosses a page boundary */
1703 	.dma_boundary =		PAGE_SIZE-1,
1704 	.no_write_same =	1,
1705 	.track_queue_depth =	1,
1706 };
1707 
1708 enum {
1709 	SCSI_GUID,
1710 	IDE_GUID,
1711 	SFC_GUID,
1712 };
1713 
1714 static const struct hv_vmbus_device_id id_table[] = {
1715 	/* SCSI guid */
1716 	{ HV_SCSI_GUID,
1717 	  .driver_data = SCSI_GUID
1718 	},
1719 	/* IDE guid */
1720 	{ HV_IDE_GUID,
1721 	  .driver_data = IDE_GUID
1722 	},
1723 	/* Fibre Channel GUID */
1724 	{
1725 	  HV_SYNTHFC_GUID,
1726 	  .driver_data = SFC_GUID
1727 	},
1728 	{ },
1729 };
1730 
1731 MODULE_DEVICE_TABLE(vmbus, id_table);
1732 
1733 static int storvsc_probe(struct hv_device *device,
1734 			const struct hv_vmbus_device_id *dev_id)
1735 {
1736 	int ret;
1737 	int num_cpus = num_online_cpus();
1738 	struct Scsi_Host *host;
1739 	struct hv_host_device *host_dev;
1740 	bool dev_is_ide = ((dev_id->driver_data == IDE_GUID) ? true : false);
1741 	bool is_fc = ((dev_id->driver_data == SFC_GUID) ? true : false);
1742 	int target = 0;
1743 	struct storvsc_device *stor_device;
1744 	int max_luns_per_target;
1745 	int max_targets;
1746 	int max_channels;
1747 	int max_sub_channels = 0;
1748 
1749 	/*
1750 	 * Based on the windows host we are running on,
1751 	 * set state to properly communicate with the host.
1752 	 */
1753 
1754 	if (vmbus_proto_version < VERSION_WIN8) {
1755 		max_luns_per_target = STORVSC_IDE_MAX_LUNS_PER_TARGET;
1756 		max_targets = STORVSC_IDE_MAX_TARGETS;
1757 		max_channels = STORVSC_IDE_MAX_CHANNELS;
1758 	} else {
1759 		max_luns_per_target = STORVSC_MAX_LUNS_PER_TARGET;
1760 		max_targets = STORVSC_MAX_TARGETS;
1761 		max_channels = STORVSC_MAX_CHANNELS;
1762 		/*
1763 		 * On Windows8 and above, we support sub-channels for storage
1764 		 * on SCSI and FC controllers.
1765 		 * The number of sub-channels offerred is based on the number of
1766 		 * VCPUs in the guest.
1767 		 */
1768 		if (!dev_is_ide)
1769 			max_sub_channels =
1770 				(num_cpus - 1) / storvsc_vcpus_per_sub_channel;
1771 	}
1772 
1773 	scsi_driver.can_queue = max_outstanding_req_per_channel *
1774 				(max_sub_channels + 1) *
1775 				(100 - ring_avail_percent_lowater) / 100;
1776 
1777 	host = scsi_host_alloc(&scsi_driver,
1778 			       sizeof(struct hv_host_device));
1779 	if (!host)
1780 		return -ENOMEM;
1781 
1782 	host_dev = shost_priv(host);
1783 	memset(host_dev, 0, sizeof(struct hv_host_device));
1784 
1785 	host_dev->port = host->host_no;
1786 	host_dev->dev = device;
1787 	host_dev->host = host;
1788 
1789 
1790 	stor_device = kzalloc(sizeof(struct storvsc_device), GFP_KERNEL);
1791 	if (!stor_device) {
1792 		ret = -ENOMEM;
1793 		goto err_out0;
1794 	}
1795 
1796 	stor_device->destroy = false;
1797 	stor_device->open_sub_channel = false;
1798 	init_waitqueue_head(&stor_device->waiting_to_drain);
1799 	stor_device->device = device;
1800 	stor_device->host = host;
1801 	hv_set_drvdata(device, stor_device);
1802 
1803 	stor_device->port_number = host->host_no;
1804 	ret = storvsc_connect_to_vsp(device, storvsc_ringbuffer_size, is_fc);
1805 	if (ret)
1806 		goto err_out1;
1807 
1808 	host_dev->path = stor_device->path_id;
1809 	host_dev->target = stor_device->target_id;
1810 
1811 	switch (dev_id->driver_data) {
1812 	case SFC_GUID:
1813 		host->max_lun = STORVSC_FC_MAX_LUNS_PER_TARGET;
1814 		host->max_id = STORVSC_FC_MAX_TARGETS;
1815 		host->max_channel = STORVSC_FC_MAX_CHANNELS - 1;
1816 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
1817 		host->transportt = fc_transport_template;
1818 #endif
1819 		break;
1820 
1821 	case SCSI_GUID:
1822 		host->max_lun = max_luns_per_target;
1823 		host->max_id = max_targets;
1824 		host->max_channel = max_channels - 1;
1825 		break;
1826 
1827 	default:
1828 		host->max_lun = STORVSC_IDE_MAX_LUNS_PER_TARGET;
1829 		host->max_id = STORVSC_IDE_MAX_TARGETS;
1830 		host->max_channel = STORVSC_IDE_MAX_CHANNELS - 1;
1831 		break;
1832 	}
1833 	/* max cmd length */
1834 	host->max_cmd_len = STORVSC_MAX_CMD_LEN;
1835 
1836 	/*
1837 	 * set the table size based on the info we got
1838 	 * from the host.
1839 	 */
1840 	host->sg_tablesize = (stor_device->max_transfer_bytes >> PAGE_SHIFT);
1841 	/*
1842 	 * Set the number of HW queues we are supporting.
1843 	 */
1844 	if (stor_device->num_sc != 0)
1845 		host->nr_hw_queues = stor_device->num_sc + 1;
1846 
1847 	/*
1848 	 * Set the error handler work queue.
1849 	 */
1850 	host_dev->handle_error_wq =
1851 			alloc_ordered_workqueue("storvsc_error_wq_%d",
1852 						WQ_MEM_RECLAIM,
1853 						host->host_no);
1854 	if (!host_dev->handle_error_wq)
1855 		goto err_out2;
1856 	INIT_WORK(&host_dev->host_scan_work, storvsc_host_scan);
1857 	/* Register the HBA and start the scsi bus scan */
1858 	ret = scsi_add_host(host, &device->device);
1859 	if (ret != 0)
1860 		goto err_out3;
1861 
1862 	if (!dev_is_ide) {
1863 		scsi_scan_host(host);
1864 	} else {
1865 		target = (device->dev_instance.b[5] << 8 |
1866 			 device->dev_instance.b[4]);
1867 		ret = scsi_add_device(host, 0, target, 0);
1868 		if (ret)
1869 			goto err_out4;
1870 	}
1871 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
1872 	if (host->transportt == fc_transport_template) {
1873 		struct fc_rport_identifiers ids = {
1874 			.roles = FC_PORT_ROLE_FCP_DUMMY_INITIATOR,
1875 		};
1876 
1877 		fc_host_node_name(host) = stor_device->node_name;
1878 		fc_host_port_name(host) = stor_device->port_name;
1879 		stor_device->rport = fc_remote_port_add(host, 0, &ids);
1880 		if (!stor_device->rport) {
1881 			ret = -ENOMEM;
1882 			goto err_out4;
1883 		}
1884 	}
1885 #endif
1886 	return 0;
1887 
1888 err_out4:
1889 	scsi_remove_host(host);
1890 
1891 err_out3:
1892 	destroy_workqueue(host_dev->handle_error_wq);
1893 
1894 err_out2:
1895 	/*
1896 	 * Once we have connected with the host, we would need to
1897 	 * to invoke storvsc_dev_remove() to rollback this state and
1898 	 * this call also frees up the stor_device; hence the jump around
1899 	 * err_out1 label.
1900 	 */
1901 	storvsc_dev_remove(device);
1902 	goto err_out0;
1903 
1904 err_out1:
1905 	kfree(stor_device->stor_chns);
1906 	kfree(stor_device);
1907 
1908 err_out0:
1909 	scsi_host_put(host);
1910 	return ret;
1911 }
1912 
1913 static int storvsc_remove(struct hv_device *dev)
1914 {
1915 	struct storvsc_device *stor_device = hv_get_drvdata(dev);
1916 	struct Scsi_Host *host = stor_device->host;
1917 	struct hv_host_device *host_dev = shost_priv(host);
1918 
1919 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
1920 	if (host->transportt == fc_transport_template) {
1921 		fc_remote_port_delete(stor_device->rport);
1922 		fc_remove_host(host);
1923 	}
1924 #endif
1925 	destroy_workqueue(host_dev->handle_error_wq);
1926 	scsi_remove_host(host);
1927 	storvsc_dev_remove(dev);
1928 	scsi_host_put(host);
1929 
1930 	return 0;
1931 }
1932 
1933 static struct hv_driver storvsc_drv = {
1934 	.name = KBUILD_MODNAME,
1935 	.id_table = id_table,
1936 	.probe = storvsc_probe,
1937 	.remove = storvsc_remove,
1938 };
1939 
1940 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
1941 static struct fc_function_template fc_transport_functions = {
1942 	.show_host_node_name = 1,
1943 	.show_host_port_name = 1,
1944 };
1945 #endif
1946 
1947 static int __init storvsc_drv_init(void)
1948 {
1949 	int ret;
1950 
1951 	/*
1952 	 * Divide the ring buffer data size (which is 1 page less
1953 	 * than the ring buffer size since that page is reserved for
1954 	 * the ring buffer indices) by the max request size (which is
1955 	 * vmbus_channel_packet_multipage_buffer + struct vstor_packet + u64)
1956 	 */
1957 	max_outstanding_req_per_channel =
1958 		((storvsc_ringbuffer_size - PAGE_SIZE) /
1959 		ALIGN(MAX_MULTIPAGE_BUFFER_PACKET +
1960 		sizeof(struct vstor_packet) + sizeof(u64) -
1961 		vmscsi_size_delta,
1962 		sizeof(u64)));
1963 
1964 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
1965 	fc_transport_template = fc_attach_transport(&fc_transport_functions);
1966 	if (!fc_transport_template)
1967 		return -ENODEV;
1968 #endif
1969 
1970 	ret = vmbus_driver_register(&storvsc_drv);
1971 
1972 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
1973 	if (ret)
1974 		fc_release_transport(fc_transport_template);
1975 #endif
1976 
1977 	return ret;
1978 }
1979 
1980 static void __exit storvsc_drv_exit(void)
1981 {
1982 	vmbus_driver_unregister(&storvsc_drv);
1983 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
1984 	fc_release_transport(fc_transport_template);
1985 #endif
1986 }
1987 
1988 MODULE_LICENSE("GPL");
1989 MODULE_DESCRIPTION("Microsoft Hyper-V virtual storage driver");
1990 module_init(storvsc_drv_init);
1991 module_exit(storvsc_drv_exit);
1992