xref: /openbmc/linux/drivers/scsi/storvsc_drv.c (revision bc5aa3a0)
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 
140 /*
141  * Platform neutral description of a scsi request -
142  * this remains the same across the write regardless of 32/64 bit
143  * note: it's patterned off the SCSI_PASS_THROUGH structure
144  */
145 #define STORVSC_MAX_CMD_LEN			0x10
146 
147 #define POST_WIN7_STORVSC_SENSE_BUFFER_SIZE	0x14
148 #define PRE_WIN8_STORVSC_SENSE_BUFFER_SIZE	0x12
149 
150 #define STORVSC_SENSE_BUFFER_SIZE		0x14
151 #define STORVSC_MAX_BUF_LEN_WITH_PADDING	0x14
152 
153 /*
154  * Sense buffer size changed in win8; have a run-time
155  * variable to track the size we should use.  This value will
156  * likely change during protocol negotiation but it is valid
157  * to start by assuming pre-Win8.
158  */
159 static int sense_buffer_size = PRE_WIN8_STORVSC_SENSE_BUFFER_SIZE;
160 
161 /*
162  * The storage protocol version is determined during the
163  * initial exchange with the host.  It will indicate which
164  * storage functionality is available in the host.
165 */
166 static int vmstor_proto_version;
167 
168 #define STORVSC_LOGGING_NONE	0
169 #define STORVSC_LOGGING_ERROR	1
170 #define STORVSC_LOGGING_WARN	2
171 
172 static int logging_level = STORVSC_LOGGING_ERROR;
173 module_param(logging_level, int, S_IRUGO|S_IWUSR);
174 MODULE_PARM_DESC(logging_level,
175 	"Logging level, 0 - None, 1 - Error (default), 2 - Warning.");
176 
177 static inline bool do_logging(int level)
178 {
179 	return logging_level >= level;
180 }
181 
182 #define storvsc_log(dev, level, fmt, ...)			\
183 do {								\
184 	if (do_logging(level))					\
185 		dev_warn(&(dev)->device, fmt, ##__VA_ARGS__);	\
186 } while (0)
187 
188 struct vmscsi_win8_extension {
189 	/*
190 	 * The following were added in Windows 8
191 	 */
192 	u16 reserve;
193 	u8  queue_tag;
194 	u8  queue_action;
195 	u32 srb_flags;
196 	u32 time_out_value;
197 	u32 queue_sort_ey;
198 } __packed;
199 
200 struct vmscsi_request {
201 	u16 length;
202 	u8 srb_status;
203 	u8 scsi_status;
204 
205 	u8  port_number;
206 	u8  path_id;
207 	u8  target_id;
208 	u8  lun;
209 
210 	u8  cdb_length;
211 	u8  sense_info_length;
212 	u8  data_in;
213 	u8  reserved;
214 
215 	u32 data_transfer_length;
216 
217 	union {
218 		u8 cdb[STORVSC_MAX_CMD_LEN];
219 		u8 sense_data[STORVSC_SENSE_BUFFER_SIZE];
220 		u8 reserved_array[STORVSC_MAX_BUF_LEN_WITH_PADDING];
221 	};
222 	/*
223 	 * The following was added in win8.
224 	 */
225 	struct vmscsi_win8_extension win8_extension;
226 
227 } __attribute((packed));
228 
229 
230 /*
231  * The size of the vmscsi_request has changed in win8. The
232  * additional size is because of new elements added to the
233  * structure. These elements are valid only when we are talking
234  * to a win8 host.
235  * Track the correction to size we need to apply. This value
236  * will likely change during protocol negotiation but it is
237  * valid to start by assuming pre-Win8.
238  */
239 static int vmscsi_size_delta = sizeof(struct vmscsi_win8_extension);
240 
241 /*
242  * The list of storage protocols in order of preference.
243  */
244 struct vmstor_protocol {
245 	int protocol_version;
246 	int sense_buffer_size;
247 	int vmscsi_size_delta;
248 };
249 
250 
251 static const struct vmstor_protocol vmstor_protocols[] = {
252 	{
253 		VMSTOR_PROTO_VERSION_WIN10,
254 		POST_WIN7_STORVSC_SENSE_BUFFER_SIZE,
255 		0
256 	},
257 	{
258 		VMSTOR_PROTO_VERSION_WIN8_1,
259 		POST_WIN7_STORVSC_SENSE_BUFFER_SIZE,
260 		0
261 	},
262 	{
263 		VMSTOR_PROTO_VERSION_WIN8,
264 		POST_WIN7_STORVSC_SENSE_BUFFER_SIZE,
265 		0
266 	},
267 	{
268 		VMSTOR_PROTO_VERSION_WIN7,
269 		PRE_WIN8_STORVSC_SENSE_BUFFER_SIZE,
270 		sizeof(struct vmscsi_win8_extension),
271 	},
272 	{
273 		VMSTOR_PROTO_VERSION_WIN6,
274 		PRE_WIN8_STORVSC_SENSE_BUFFER_SIZE,
275 		sizeof(struct vmscsi_win8_extension),
276 	}
277 };
278 
279 
280 /*
281  * This structure is sent during the intialization phase to get the different
282  * properties of the channel.
283  */
284 
285 #define STORAGE_CHANNEL_SUPPORTS_MULTI_CHANNEL		0x1
286 
287 struct vmstorage_channel_properties {
288 	u32 reserved;
289 	u16 max_channel_cnt;
290 	u16 reserved1;
291 
292 	u32 flags;
293 	u32   max_transfer_bytes;
294 
295 	u64  reserved2;
296 } __packed;
297 
298 /*  This structure is sent during the storage protocol negotiations. */
299 struct vmstorage_protocol_version {
300 	/* Major (MSW) and minor (LSW) version numbers. */
301 	u16 major_minor;
302 
303 	/*
304 	 * Revision number is auto-incremented whenever this file is changed
305 	 * (See FILL_VMSTOR_REVISION macro above).  Mismatch does not
306 	 * definitely indicate incompatibility--but it does indicate mismatched
307 	 * builds.
308 	 * This is only used on the windows side. Just set it to 0.
309 	 */
310 	u16 revision;
311 } __packed;
312 
313 /* Channel Property Flags */
314 #define STORAGE_CHANNEL_REMOVABLE_FLAG		0x1
315 #define STORAGE_CHANNEL_EMULATED_IDE_FLAG	0x2
316 
317 struct vstor_packet {
318 	/* Requested operation type */
319 	enum vstor_packet_operation operation;
320 
321 	/*  Flags - see below for values */
322 	u32 flags;
323 
324 	/* Status of the request returned from the server side. */
325 	u32 status;
326 
327 	/* Data payload area */
328 	union {
329 		/*
330 		 * Structure used to forward SCSI commands from the
331 		 * client to the server.
332 		 */
333 		struct vmscsi_request vm_srb;
334 
335 		/* Structure used to query channel properties. */
336 		struct vmstorage_channel_properties storage_channel_properties;
337 
338 		/* Used during version negotiations. */
339 		struct vmstorage_protocol_version version;
340 
341 		/* Fibre channel address packet */
342 		struct hv_fc_wwn_packet wwn_packet;
343 
344 		/* Number of sub-channels to create */
345 		u16 sub_channel_count;
346 
347 		/* This will be the maximum of the union members */
348 		u8  buffer[0x34];
349 	};
350 } __packed;
351 
352 /*
353  * Packet Flags:
354  *
355  * This flag indicates that the server should send back a completion for this
356  * packet.
357  */
358 
359 #define REQUEST_COMPLETION_FLAG	0x1
360 
361 /* Matches Windows-end */
362 enum storvsc_request_type {
363 	WRITE_TYPE = 0,
364 	READ_TYPE,
365 	UNKNOWN_TYPE,
366 };
367 
368 /*
369  * SRB status codes and masks; a subset of the codes used here.
370  */
371 
372 #define SRB_STATUS_AUTOSENSE_VALID	0x80
373 #define SRB_STATUS_QUEUE_FROZEN		0x40
374 #define SRB_STATUS_INVALID_LUN	0x20
375 #define SRB_STATUS_SUCCESS	0x01
376 #define SRB_STATUS_ABORTED	0x02
377 #define SRB_STATUS_ERROR	0x04
378 
379 #define SRB_STATUS(status) \
380 	(status & ~(SRB_STATUS_AUTOSENSE_VALID | SRB_STATUS_QUEUE_FROZEN))
381 /*
382  * This is the end of Protocol specific defines.
383  */
384 
385 static int storvsc_ringbuffer_size = (256 * PAGE_SIZE);
386 static u32 max_outstanding_req_per_channel;
387 
388 static int storvsc_vcpus_per_sub_channel = 4;
389 
390 module_param(storvsc_ringbuffer_size, int, S_IRUGO);
391 MODULE_PARM_DESC(storvsc_ringbuffer_size, "Ring buffer size (bytes)");
392 
393 module_param(storvsc_vcpus_per_sub_channel, int, S_IRUGO);
394 MODULE_PARM_DESC(storvsc_vcpus_per_sub_channel, "Ratio of VCPUs to subchannels");
395 /*
396  * Timeout in seconds for all devices managed by this driver.
397  */
398 static int storvsc_timeout = 180;
399 
400 static int msft_blist_flags = BLIST_TRY_VPD_PAGES;
401 
402 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
403 static struct scsi_transport_template *fc_transport_template;
404 #endif
405 
406 static void storvsc_on_channel_callback(void *context);
407 
408 #define STORVSC_MAX_LUNS_PER_TARGET			255
409 #define STORVSC_MAX_TARGETS				2
410 #define STORVSC_MAX_CHANNELS				8
411 
412 #define STORVSC_FC_MAX_LUNS_PER_TARGET			255
413 #define STORVSC_FC_MAX_TARGETS				128
414 #define STORVSC_FC_MAX_CHANNELS				8
415 
416 #define STORVSC_IDE_MAX_LUNS_PER_TARGET			64
417 #define STORVSC_IDE_MAX_TARGETS				1
418 #define STORVSC_IDE_MAX_CHANNELS			1
419 
420 struct storvsc_cmd_request {
421 	struct scsi_cmnd *cmd;
422 
423 	struct hv_device *device;
424 
425 	/* Synchronize the request/response if needed */
426 	struct completion wait_event;
427 
428 	struct vmbus_channel_packet_multipage_buffer mpb;
429 	struct vmbus_packet_mpb_array *payload;
430 	u32 payload_sz;
431 
432 	struct vstor_packet vstor_packet;
433 };
434 
435 
436 /* A storvsc device is a device object that contains a vmbus channel */
437 struct storvsc_device {
438 	struct hv_device *device;
439 
440 	bool	 destroy;
441 	bool	 drain_notify;
442 	bool	 open_sub_channel;
443 	atomic_t num_outstanding_req;
444 	struct Scsi_Host *host;
445 
446 	wait_queue_head_t waiting_to_drain;
447 
448 	/*
449 	 * Each unique Port/Path/Target represents 1 channel ie scsi
450 	 * controller. In reality, the pathid, targetid is always 0
451 	 * and the port is set by us
452 	 */
453 	unsigned int port_number;
454 	unsigned char path_id;
455 	unsigned char target_id;
456 
457 	/*
458 	 * Max I/O, the device can support.
459 	 */
460 	u32   max_transfer_bytes;
461 	/* Used for vsc/vsp channel reset process */
462 	struct storvsc_cmd_request init_request;
463 	struct storvsc_cmd_request reset_request;
464 	/*
465 	 * Currently active port and node names for FC devices.
466 	 */
467 	u64 node_name;
468 	u64 port_name;
469 };
470 
471 struct hv_host_device {
472 	struct hv_device *dev;
473 	unsigned int port;
474 	unsigned char path;
475 	unsigned char target;
476 };
477 
478 struct storvsc_scan_work {
479 	struct work_struct work;
480 	struct Scsi_Host *host;
481 	u8 lun;
482 	u8 tgt_id;
483 };
484 
485 static void storvsc_device_scan(struct work_struct *work)
486 {
487 	struct storvsc_scan_work *wrk;
488 	struct scsi_device *sdev;
489 
490 	wrk = container_of(work, struct storvsc_scan_work, work);
491 
492 	sdev = scsi_device_lookup(wrk->host, 0, wrk->tgt_id, wrk->lun);
493 	if (!sdev)
494 		goto done;
495 	scsi_rescan_device(&sdev->sdev_gendev);
496 	scsi_device_put(sdev);
497 
498 done:
499 	kfree(wrk);
500 }
501 
502 static void storvsc_host_scan(struct work_struct *work)
503 {
504 	struct storvsc_scan_work *wrk;
505 	struct Scsi_Host *host;
506 	struct scsi_device *sdev;
507 
508 	wrk = container_of(work, struct storvsc_scan_work, work);
509 	host = wrk->host;
510 
511 	/*
512 	 * Before scanning the host, first check to see if any of the
513 	 * currrently known devices have been hot removed. We issue a
514 	 * "unit ready" command against all currently known devices.
515 	 * This I/O will result in an error for devices that have been
516 	 * removed. As part of handling the I/O error, we remove the device.
517 	 *
518 	 * When a LUN is added or removed, the host sends us a signal to
519 	 * scan the host. Thus we are forced to discover the LUNs that
520 	 * may have been removed this way.
521 	 */
522 	mutex_lock(&host->scan_mutex);
523 	shost_for_each_device(sdev, host)
524 		scsi_test_unit_ready(sdev, 1, 1, NULL);
525 	mutex_unlock(&host->scan_mutex);
526 	/*
527 	 * Now scan the host to discover LUNs that may have been added.
528 	 */
529 	scsi_scan_host(host);
530 
531 	kfree(wrk);
532 }
533 
534 static void storvsc_remove_lun(struct work_struct *work)
535 {
536 	struct storvsc_scan_work *wrk;
537 	struct scsi_device *sdev;
538 
539 	wrk = container_of(work, struct storvsc_scan_work, work);
540 	if (!scsi_host_get(wrk->host))
541 		goto done;
542 
543 	sdev = scsi_device_lookup(wrk->host, 0, wrk->tgt_id, wrk->lun);
544 
545 	if (sdev) {
546 		scsi_remove_device(sdev);
547 		scsi_device_put(sdev);
548 	}
549 	scsi_host_put(wrk->host);
550 
551 done:
552 	kfree(wrk);
553 }
554 
555 
556 /*
557  * We can get incoming messages from the host that are not in response to
558  * messages that we have sent out. An example of this would be messages
559  * received by the guest to notify dynamic addition/removal of LUNs. To
560  * deal with potential race conditions where the driver may be in the
561  * midst of being unloaded when we might receive an unsolicited message
562  * from the host, we have implemented a mechanism to gurantee sequential
563  * consistency:
564  *
565  * 1) Once the device is marked as being destroyed, we will fail all
566  *    outgoing messages.
567  * 2) We permit incoming messages when the device is being destroyed,
568  *    only to properly account for messages already sent out.
569  */
570 
571 static inline struct storvsc_device *get_out_stor_device(
572 					struct hv_device *device)
573 {
574 	struct storvsc_device *stor_device;
575 
576 	stor_device = hv_get_drvdata(device);
577 
578 	if (stor_device && stor_device->destroy)
579 		stor_device = NULL;
580 
581 	return stor_device;
582 }
583 
584 
585 static inline void storvsc_wait_to_drain(struct storvsc_device *dev)
586 {
587 	dev->drain_notify = true;
588 	wait_event(dev->waiting_to_drain,
589 		   atomic_read(&dev->num_outstanding_req) == 0);
590 	dev->drain_notify = false;
591 }
592 
593 static inline struct storvsc_device *get_in_stor_device(
594 					struct hv_device *device)
595 {
596 	struct storvsc_device *stor_device;
597 
598 	stor_device = hv_get_drvdata(device);
599 
600 	if (!stor_device)
601 		goto get_in_err;
602 
603 	/*
604 	 * If the device is being destroyed; allow incoming
605 	 * traffic only to cleanup outstanding requests.
606 	 */
607 
608 	if (stor_device->destroy  &&
609 		(atomic_read(&stor_device->num_outstanding_req) == 0))
610 		stor_device = NULL;
611 
612 get_in_err:
613 	return stor_device;
614 
615 }
616 
617 static void handle_sc_creation(struct vmbus_channel *new_sc)
618 {
619 	struct hv_device *device = new_sc->primary_channel->device_obj;
620 	struct storvsc_device *stor_device;
621 	struct vmstorage_channel_properties props;
622 
623 	stor_device = get_out_stor_device(device);
624 	if (!stor_device)
625 		return;
626 
627 	if (stor_device->open_sub_channel == false)
628 		return;
629 
630 	memset(&props, 0, sizeof(struct vmstorage_channel_properties));
631 
632 	vmbus_open(new_sc,
633 		   storvsc_ringbuffer_size,
634 		   storvsc_ringbuffer_size,
635 		   (void *)&props,
636 		   sizeof(struct vmstorage_channel_properties),
637 		   storvsc_on_channel_callback, new_sc);
638 }
639 
640 static void  handle_multichannel_storage(struct hv_device *device, int max_chns)
641 {
642 	struct storvsc_device *stor_device;
643 	int num_cpus = num_online_cpus();
644 	int num_sc;
645 	struct storvsc_cmd_request *request;
646 	struct vstor_packet *vstor_packet;
647 	int ret, t;
648 
649 	num_sc = ((max_chns > num_cpus) ? num_cpus : max_chns);
650 	stor_device = get_out_stor_device(device);
651 	if (!stor_device)
652 		return;
653 
654 	request = &stor_device->init_request;
655 	vstor_packet = &request->vstor_packet;
656 
657 	stor_device->open_sub_channel = true;
658 	/*
659 	 * Establish a handler for dealing with subchannels.
660 	 */
661 	vmbus_set_sc_create_callback(device->channel, handle_sc_creation);
662 
663 	/*
664 	 * Check to see if sub-channels have already been created. This
665 	 * can happen when this driver is re-loaded after unloading.
666 	 */
667 
668 	if (vmbus_are_subchannels_present(device->channel))
669 		return;
670 
671 	stor_device->open_sub_channel = false;
672 	/*
673 	 * Request the host to create sub-channels.
674 	 */
675 	memset(request, 0, sizeof(struct storvsc_cmd_request));
676 	init_completion(&request->wait_event);
677 	vstor_packet->operation = VSTOR_OPERATION_CREATE_SUB_CHANNELS;
678 	vstor_packet->flags = REQUEST_COMPLETION_FLAG;
679 	vstor_packet->sub_channel_count = num_sc;
680 
681 	ret = vmbus_sendpacket(device->channel, vstor_packet,
682 			       (sizeof(struct vstor_packet) -
683 			       vmscsi_size_delta),
684 			       (unsigned long)request,
685 			       VM_PKT_DATA_INBAND,
686 			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
687 
688 	if (ret != 0)
689 		return;
690 
691 	t = wait_for_completion_timeout(&request->wait_event, 10*HZ);
692 	if (t == 0)
693 		return;
694 
695 	if (vstor_packet->operation != VSTOR_OPERATION_COMPLETE_IO ||
696 	    vstor_packet->status != 0)
697 		return;
698 
699 	/*
700 	 * Now that we created the sub-channels, invoke the check; this
701 	 * may trigger the callback.
702 	 */
703 	stor_device->open_sub_channel = true;
704 	vmbus_are_subchannels_present(device->channel);
705 }
706 
707 static void cache_wwn(struct storvsc_device *stor_device,
708 		      struct vstor_packet *vstor_packet)
709 {
710 	/*
711 	 * Cache the currently active port and node ww names.
712 	 */
713 	if (vstor_packet->wwn_packet.primary_active) {
714 		stor_device->node_name =
715 			wwn_to_u64(vstor_packet->wwn_packet.primary_node_wwn);
716 		stor_device->port_name =
717 			wwn_to_u64(vstor_packet->wwn_packet.primary_port_wwn);
718 	} else {
719 		stor_device->node_name =
720 			wwn_to_u64(vstor_packet->wwn_packet.secondary_node_wwn);
721 		stor_device->port_name =
722 			wwn_to_u64(vstor_packet->wwn_packet.secondary_port_wwn);
723 	}
724 }
725 
726 
727 static int storvsc_execute_vstor_op(struct hv_device *device,
728 				    struct storvsc_cmd_request *request,
729 				    bool status_check)
730 {
731 	struct vstor_packet *vstor_packet;
732 	int ret, t;
733 
734 	vstor_packet = &request->vstor_packet;
735 
736 	init_completion(&request->wait_event);
737 	vstor_packet->flags = REQUEST_COMPLETION_FLAG;
738 
739 	ret = vmbus_sendpacket(device->channel, vstor_packet,
740 			       (sizeof(struct vstor_packet) -
741 			       vmscsi_size_delta),
742 			       (unsigned long)request,
743 			       VM_PKT_DATA_INBAND,
744 			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
745 	if (ret != 0)
746 		return ret;
747 
748 	t = wait_for_completion_timeout(&request->wait_event, 5*HZ);
749 	if (t == 0)
750 		return -ETIMEDOUT;
751 
752 	if (!status_check)
753 		return ret;
754 
755 	if (vstor_packet->operation != VSTOR_OPERATION_COMPLETE_IO ||
756 	    vstor_packet->status != 0)
757 		return -EINVAL;
758 
759 	return ret;
760 }
761 
762 static int storvsc_channel_init(struct hv_device *device, bool is_fc)
763 {
764 	struct storvsc_device *stor_device;
765 	struct storvsc_cmd_request *request;
766 	struct vstor_packet *vstor_packet;
767 	int ret, i;
768 	int max_chns;
769 	bool process_sub_channels = false;
770 
771 	stor_device = get_out_stor_device(device);
772 	if (!stor_device)
773 		return -ENODEV;
774 
775 	request = &stor_device->init_request;
776 	vstor_packet = &request->vstor_packet;
777 
778 	/*
779 	 * Now, initiate the vsc/vsp initialization protocol on the open
780 	 * channel
781 	 */
782 	memset(request, 0, sizeof(struct storvsc_cmd_request));
783 	vstor_packet->operation = VSTOR_OPERATION_BEGIN_INITIALIZATION;
784 	ret = storvsc_execute_vstor_op(device, request, true);
785 	if (ret)
786 		return ret;
787 	/*
788 	 * Query host supported protocol version.
789 	 */
790 
791 	for (i = 0; i < ARRAY_SIZE(vmstor_protocols); i++) {
792 		/* reuse the packet for version range supported */
793 		memset(vstor_packet, 0, sizeof(struct vstor_packet));
794 		vstor_packet->operation =
795 			VSTOR_OPERATION_QUERY_PROTOCOL_VERSION;
796 
797 		vstor_packet->version.major_minor =
798 			vmstor_protocols[i].protocol_version;
799 
800 		/*
801 		 * The revision number is only used in Windows; set it to 0.
802 		 */
803 		vstor_packet->version.revision = 0;
804 		ret = storvsc_execute_vstor_op(device, request, false);
805 		if (ret != 0)
806 			return ret;
807 
808 		if (vstor_packet->operation != VSTOR_OPERATION_COMPLETE_IO)
809 			return -EINVAL;
810 
811 		if (vstor_packet->status == 0) {
812 			vmstor_proto_version =
813 				vmstor_protocols[i].protocol_version;
814 
815 			sense_buffer_size =
816 				vmstor_protocols[i].sense_buffer_size;
817 
818 			vmscsi_size_delta =
819 				vmstor_protocols[i].vmscsi_size_delta;
820 
821 			break;
822 		}
823 	}
824 
825 	if (vstor_packet->status != 0)
826 		return -EINVAL;
827 
828 
829 	memset(vstor_packet, 0, sizeof(struct vstor_packet));
830 	vstor_packet->operation = VSTOR_OPERATION_QUERY_PROPERTIES;
831 	ret = storvsc_execute_vstor_op(device, request, true);
832 	if (ret != 0)
833 		return ret;
834 
835 	/*
836 	 * Check to see if multi-channel support is there.
837 	 * Hosts that implement protocol version of 5.1 and above
838 	 * support multi-channel.
839 	 */
840 	max_chns = vstor_packet->storage_channel_properties.max_channel_cnt;
841 	if (vmstor_proto_version >= VMSTOR_PROTO_VERSION_WIN8) {
842 		if (vstor_packet->storage_channel_properties.flags &
843 		    STORAGE_CHANNEL_SUPPORTS_MULTI_CHANNEL)
844 			process_sub_channels = true;
845 	}
846 	stor_device->max_transfer_bytes =
847 		vstor_packet->storage_channel_properties.max_transfer_bytes;
848 
849 	if (!is_fc)
850 		goto done;
851 
852 	/*
853 	 * For FC devices retrieve FC HBA data.
854 	 */
855 	memset(vstor_packet, 0, sizeof(struct vstor_packet));
856 	vstor_packet->operation = VSTOR_OPERATION_FCHBA_DATA;
857 	ret = storvsc_execute_vstor_op(device, request, true);
858 	if (ret != 0)
859 		return ret;
860 
861 	/*
862 	 * Cache the currently active port and node ww names.
863 	 */
864 	cache_wwn(stor_device, vstor_packet);
865 
866 done:
867 
868 	memset(vstor_packet, 0, sizeof(struct vstor_packet));
869 	vstor_packet->operation = VSTOR_OPERATION_END_INITIALIZATION;
870 	ret = storvsc_execute_vstor_op(device, request, true);
871 	if (ret != 0)
872 		return ret;
873 
874 	if (process_sub_channels)
875 		handle_multichannel_storage(device, max_chns);
876 
877 	return ret;
878 }
879 
880 static void storvsc_handle_error(struct vmscsi_request *vm_srb,
881 				struct scsi_cmnd *scmnd,
882 				struct Scsi_Host *host,
883 				u8 asc, u8 ascq)
884 {
885 	struct storvsc_scan_work *wrk;
886 	void (*process_err_fn)(struct work_struct *work);
887 	bool do_work = false;
888 
889 	switch (SRB_STATUS(vm_srb->srb_status)) {
890 	case SRB_STATUS_ERROR:
891 		/*
892 		 * If there is an error; offline the device since all
893 		 * error recovery strategies would have already been
894 		 * deployed on the host side. However, if the command
895 		 * were a pass-through command deal with it appropriately.
896 		 */
897 		switch (scmnd->cmnd[0]) {
898 		case ATA_16:
899 		case ATA_12:
900 			set_host_byte(scmnd, DID_PASSTHROUGH);
901 			break;
902 		/*
903 		 * On Some Windows hosts TEST_UNIT_READY command can return
904 		 * SRB_STATUS_ERROR, let the upper level code deal with it
905 		 * based on the sense information.
906 		 */
907 		case TEST_UNIT_READY:
908 			break;
909 		default:
910 			set_host_byte(scmnd, DID_TARGET_FAILURE);
911 		}
912 		break;
913 	case SRB_STATUS_INVALID_LUN:
914 		do_work = true;
915 		process_err_fn = storvsc_remove_lun;
916 		break;
917 	case SRB_STATUS_ABORTED:
918 		if (vm_srb->srb_status & SRB_STATUS_AUTOSENSE_VALID &&
919 		    (asc == 0x2a) && (ascq == 0x9)) {
920 			do_work = true;
921 			process_err_fn = storvsc_device_scan;
922 			/*
923 			 * Retry the I/O that trigerred this.
924 			 */
925 			set_host_byte(scmnd, DID_REQUEUE);
926 		}
927 		break;
928 	}
929 
930 	if (!do_work)
931 		return;
932 
933 	/*
934 	 * We need to schedule work to process this error; schedule it.
935 	 */
936 	wrk = kmalloc(sizeof(struct storvsc_scan_work), GFP_ATOMIC);
937 	if (!wrk) {
938 		set_host_byte(scmnd, DID_TARGET_FAILURE);
939 		return;
940 	}
941 
942 	wrk->host = host;
943 	wrk->lun = vm_srb->lun;
944 	wrk->tgt_id = vm_srb->target_id;
945 	INIT_WORK(&wrk->work, process_err_fn);
946 	schedule_work(&wrk->work);
947 }
948 
949 
950 static void storvsc_command_completion(struct storvsc_cmd_request *cmd_request,
951 				       struct storvsc_device *stor_dev)
952 {
953 	struct scsi_cmnd *scmnd = cmd_request->cmd;
954 	struct scsi_sense_hdr sense_hdr;
955 	struct vmscsi_request *vm_srb;
956 	struct Scsi_Host *host;
957 	u32 payload_sz = cmd_request->payload_sz;
958 	void *payload = cmd_request->payload;
959 
960 	host = stor_dev->host;
961 
962 	vm_srb = &cmd_request->vstor_packet.vm_srb;
963 
964 	scmnd->result = vm_srb->scsi_status;
965 
966 	if (scmnd->result) {
967 		if (scsi_normalize_sense(scmnd->sense_buffer,
968 				SCSI_SENSE_BUFFERSIZE, &sense_hdr) &&
969 		    !(sense_hdr.sense_key == NOT_READY &&
970 				 sense_hdr.asc == 0x03A) &&
971 		    do_logging(STORVSC_LOGGING_ERROR))
972 			scsi_print_sense_hdr(scmnd->device, "storvsc",
973 					     &sense_hdr);
974 	}
975 
976 	if (vm_srb->srb_status != SRB_STATUS_SUCCESS)
977 		storvsc_handle_error(vm_srb, scmnd, host, sense_hdr.asc,
978 					 sense_hdr.ascq);
979 
980 	scsi_set_resid(scmnd,
981 		cmd_request->payload->range.len -
982 		vm_srb->data_transfer_length);
983 
984 	scmnd->scsi_done(scmnd);
985 
986 	if (payload_sz >
987 		sizeof(struct vmbus_channel_packet_multipage_buffer))
988 		kfree(payload);
989 }
990 
991 static void storvsc_on_io_completion(struct storvsc_device *stor_device,
992 				  struct vstor_packet *vstor_packet,
993 				  struct storvsc_cmd_request *request)
994 {
995 	struct vstor_packet *stor_pkt;
996 	struct hv_device *device = stor_device->device;
997 
998 	stor_pkt = &request->vstor_packet;
999 
1000 	/*
1001 	 * The current SCSI handling on the host side does
1002 	 * not correctly handle:
1003 	 * INQUIRY command with page code parameter set to 0x80
1004 	 * MODE_SENSE command with cmd[2] == 0x1c
1005 	 *
1006 	 * Setup srb and scsi status so this won't be fatal.
1007 	 * We do this so we can distinguish truly fatal failues
1008 	 * (srb status == 0x4) and off-line the device in that case.
1009 	 */
1010 
1011 	if ((stor_pkt->vm_srb.cdb[0] == INQUIRY) ||
1012 	   (stor_pkt->vm_srb.cdb[0] == MODE_SENSE)) {
1013 		vstor_packet->vm_srb.scsi_status = 0;
1014 		vstor_packet->vm_srb.srb_status = SRB_STATUS_SUCCESS;
1015 	}
1016 
1017 
1018 	/* Copy over the status...etc */
1019 	stor_pkt->vm_srb.scsi_status = vstor_packet->vm_srb.scsi_status;
1020 	stor_pkt->vm_srb.srb_status = vstor_packet->vm_srb.srb_status;
1021 	stor_pkt->vm_srb.sense_info_length =
1022 	vstor_packet->vm_srb.sense_info_length;
1023 
1024 	if (vstor_packet->vm_srb.scsi_status != 0 ||
1025 	    vstor_packet->vm_srb.srb_status != SRB_STATUS_SUCCESS)
1026 		storvsc_log(device, STORVSC_LOGGING_WARN,
1027 			"cmd 0x%x scsi status 0x%x srb status 0x%x\n",
1028 			stor_pkt->vm_srb.cdb[0],
1029 			vstor_packet->vm_srb.scsi_status,
1030 			vstor_packet->vm_srb.srb_status);
1031 
1032 	if ((vstor_packet->vm_srb.scsi_status & 0xFF) == 0x02) {
1033 		/* CHECK_CONDITION */
1034 		if (vstor_packet->vm_srb.srb_status &
1035 			SRB_STATUS_AUTOSENSE_VALID) {
1036 			/* autosense data available */
1037 
1038 			storvsc_log(device, STORVSC_LOGGING_WARN,
1039 				"stor pkt %p autosense data valid - len %d\n",
1040 				request, vstor_packet->vm_srb.sense_info_length);
1041 
1042 			memcpy(request->cmd->sense_buffer,
1043 			       vstor_packet->vm_srb.sense_data,
1044 			       vstor_packet->vm_srb.sense_info_length);
1045 
1046 		}
1047 	}
1048 
1049 	stor_pkt->vm_srb.data_transfer_length =
1050 	vstor_packet->vm_srb.data_transfer_length;
1051 
1052 	storvsc_command_completion(request, stor_device);
1053 
1054 	if (atomic_dec_and_test(&stor_device->num_outstanding_req) &&
1055 		stor_device->drain_notify)
1056 		wake_up(&stor_device->waiting_to_drain);
1057 
1058 
1059 }
1060 
1061 static void storvsc_on_receive(struct storvsc_device *stor_device,
1062 			     struct vstor_packet *vstor_packet,
1063 			     struct storvsc_cmd_request *request)
1064 {
1065 	struct storvsc_scan_work *work;
1066 
1067 	switch (vstor_packet->operation) {
1068 	case VSTOR_OPERATION_COMPLETE_IO:
1069 		storvsc_on_io_completion(stor_device, vstor_packet, request);
1070 		break;
1071 
1072 	case VSTOR_OPERATION_REMOVE_DEVICE:
1073 	case VSTOR_OPERATION_ENUMERATE_BUS:
1074 		work = kmalloc(sizeof(struct storvsc_scan_work), GFP_ATOMIC);
1075 		if (!work)
1076 			return;
1077 
1078 		INIT_WORK(&work->work, storvsc_host_scan);
1079 		work->host = stor_device->host;
1080 		schedule_work(&work->work);
1081 		break;
1082 
1083 	case VSTOR_OPERATION_FCHBA_DATA:
1084 		cache_wwn(stor_device, vstor_packet);
1085 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
1086 		fc_host_node_name(stor_device->host) = stor_device->node_name;
1087 		fc_host_port_name(stor_device->host) = stor_device->port_name;
1088 #endif
1089 		break;
1090 	default:
1091 		break;
1092 	}
1093 }
1094 
1095 static void storvsc_on_channel_callback(void *context)
1096 {
1097 	struct vmbus_channel *channel = (struct vmbus_channel *)context;
1098 	struct hv_device *device;
1099 	struct storvsc_device *stor_device;
1100 	u32 bytes_recvd;
1101 	u64 request_id;
1102 	unsigned char packet[ALIGN(sizeof(struct vstor_packet), 8)];
1103 	struct storvsc_cmd_request *request;
1104 	int ret;
1105 
1106 	if (channel->primary_channel != NULL)
1107 		device = channel->primary_channel->device_obj;
1108 	else
1109 		device = channel->device_obj;
1110 
1111 	stor_device = get_in_stor_device(device);
1112 	if (!stor_device)
1113 		return;
1114 
1115 	do {
1116 		ret = vmbus_recvpacket(channel, packet,
1117 				       ALIGN((sizeof(struct vstor_packet) -
1118 					     vmscsi_size_delta), 8),
1119 				       &bytes_recvd, &request_id);
1120 		if (ret == 0 && bytes_recvd > 0) {
1121 
1122 			request = (struct storvsc_cmd_request *)
1123 					(unsigned long)request_id;
1124 
1125 			if ((request == &stor_device->init_request) ||
1126 			    (request == &stor_device->reset_request)) {
1127 
1128 				memcpy(&request->vstor_packet, packet,
1129 				       (sizeof(struct vstor_packet) -
1130 					vmscsi_size_delta));
1131 				complete(&request->wait_event);
1132 			} else {
1133 				storvsc_on_receive(stor_device,
1134 						(struct vstor_packet *)packet,
1135 						request);
1136 			}
1137 		} else {
1138 			break;
1139 		}
1140 	} while (1);
1141 
1142 	return;
1143 }
1144 
1145 static int storvsc_connect_to_vsp(struct hv_device *device, u32 ring_size,
1146 				  bool is_fc)
1147 {
1148 	struct vmstorage_channel_properties props;
1149 	int ret;
1150 
1151 	memset(&props, 0, sizeof(struct vmstorage_channel_properties));
1152 
1153 	ret = vmbus_open(device->channel,
1154 			 ring_size,
1155 			 ring_size,
1156 			 (void *)&props,
1157 			 sizeof(struct vmstorage_channel_properties),
1158 			 storvsc_on_channel_callback, device->channel);
1159 
1160 	if (ret != 0)
1161 		return ret;
1162 
1163 	ret = storvsc_channel_init(device, is_fc);
1164 
1165 	return ret;
1166 }
1167 
1168 static int storvsc_dev_remove(struct hv_device *device)
1169 {
1170 	struct storvsc_device *stor_device;
1171 	unsigned long flags;
1172 
1173 	stor_device = hv_get_drvdata(device);
1174 
1175 	spin_lock_irqsave(&device->channel->inbound_lock, flags);
1176 	stor_device->destroy = true;
1177 	spin_unlock_irqrestore(&device->channel->inbound_lock, flags);
1178 
1179 	/*
1180 	 * At this point, all outbound traffic should be disable. We
1181 	 * only allow inbound traffic (responses) to proceed so that
1182 	 * outstanding requests can be completed.
1183 	 */
1184 
1185 	storvsc_wait_to_drain(stor_device);
1186 
1187 	/*
1188 	 * Since we have already drained, we don't need to busy wait
1189 	 * as was done in final_release_stor_device()
1190 	 * Note that we cannot set the ext pointer to NULL until
1191 	 * we have drained - to drain the outgoing packets, we need to
1192 	 * allow incoming packets.
1193 	 */
1194 	spin_lock_irqsave(&device->channel->inbound_lock, flags);
1195 	hv_set_drvdata(device, NULL);
1196 	spin_unlock_irqrestore(&device->channel->inbound_lock, flags);
1197 
1198 	/* Close the channel */
1199 	vmbus_close(device->channel);
1200 
1201 	kfree(stor_device);
1202 	return 0;
1203 }
1204 
1205 static int storvsc_do_io(struct hv_device *device,
1206 			 struct storvsc_cmd_request *request)
1207 {
1208 	struct storvsc_device *stor_device;
1209 	struct vstor_packet *vstor_packet;
1210 	struct vmbus_channel *outgoing_channel;
1211 	int ret = 0;
1212 
1213 	vstor_packet = &request->vstor_packet;
1214 	stor_device = get_out_stor_device(device);
1215 
1216 	if (!stor_device)
1217 		return -ENODEV;
1218 
1219 
1220 	request->device  = device;
1221 	/*
1222 	 * Select an an appropriate channel to send the request out.
1223 	 */
1224 
1225 	outgoing_channel = vmbus_get_outgoing_channel(device->channel);
1226 
1227 
1228 	vstor_packet->flags |= REQUEST_COMPLETION_FLAG;
1229 
1230 	vstor_packet->vm_srb.length = (sizeof(struct vmscsi_request) -
1231 					vmscsi_size_delta);
1232 
1233 
1234 	vstor_packet->vm_srb.sense_info_length = sense_buffer_size;
1235 
1236 
1237 	vstor_packet->vm_srb.data_transfer_length =
1238 	request->payload->range.len;
1239 
1240 	vstor_packet->operation = VSTOR_OPERATION_EXECUTE_SRB;
1241 
1242 	if (request->payload->range.len) {
1243 
1244 		ret = vmbus_sendpacket_mpb_desc(outgoing_channel,
1245 				request->payload, request->payload_sz,
1246 				vstor_packet,
1247 				(sizeof(struct vstor_packet) -
1248 				vmscsi_size_delta),
1249 				(unsigned long)request);
1250 	} else {
1251 		ret = vmbus_sendpacket(outgoing_channel, vstor_packet,
1252 			       (sizeof(struct vstor_packet) -
1253 				vmscsi_size_delta),
1254 			       (unsigned long)request,
1255 			       VM_PKT_DATA_INBAND,
1256 			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
1257 	}
1258 
1259 	if (ret != 0)
1260 		return ret;
1261 
1262 	atomic_inc(&stor_device->num_outstanding_req);
1263 
1264 	return ret;
1265 }
1266 
1267 static int storvsc_device_configure(struct scsi_device *sdevice)
1268 {
1269 
1270 	blk_queue_max_segment_size(sdevice->request_queue, PAGE_SIZE);
1271 
1272 	blk_queue_bounce_limit(sdevice->request_queue, BLK_BOUNCE_ANY);
1273 
1274 	blk_queue_rq_timeout(sdevice->request_queue, (storvsc_timeout * HZ));
1275 
1276 	/* Ensure there are no gaps in presented sgls */
1277 	blk_queue_virt_boundary(sdevice->request_queue, PAGE_SIZE - 1);
1278 
1279 	sdevice->no_write_same = 1;
1280 
1281 	/*
1282 	 * Add blist flags to permit the reading of the VPD pages even when
1283 	 * the target may claim SPC-2 compliance. MSFT targets currently
1284 	 * claim SPC-2 compliance while they implement post SPC-2 features.
1285 	 * With this patch we can correctly handle WRITE_SAME_16 issues.
1286 	 */
1287 	sdevice->sdev_bflags |= msft_blist_flags;
1288 
1289 	/*
1290 	 * If the host is WIN8 or WIN8 R2, claim conformance to SPC-3
1291 	 * if the device is a MSFT virtual device.  If the host is
1292 	 * WIN10 or newer, allow write_same.
1293 	 */
1294 	if (!strncmp(sdevice->vendor, "Msft", 4)) {
1295 		switch (vmstor_proto_version) {
1296 		case VMSTOR_PROTO_VERSION_WIN8:
1297 		case VMSTOR_PROTO_VERSION_WIN8_1:
1298 			sdevice->scsi_level = SCSI_SPC_3;
1299 			break;
1300 		}
1301 
1302 		if (vmstor_proto_version >= VMSTOR_PROTO_VERSION_WIN10)
1303 			sdevice->no_write_same = 0;
1304 	}
1305 
1306 	return 0;
1307 }
1308 
1309 static int storvsc_get_chs(struct scsi_device *sdev, struct block_device * bdev,
1310 			   sector_t capacity, int *info)
1311 {
1312 	sector_t nsect = capacity;
1313 	sector_t cylinders = nsect;
1314 	int heads, sectors_pt;
1315 
1316 	/*
1317 	 * We are making up these values; let us keep it simple.
1318 	 */
1319 	heads = 0xff;
1320 	sectors_pt = 0x3f;      /* Sectors per track */
1321 	sector_div(cylinders, heads * sectors_pt);
1322 	if ((sector_t)(cylinders + 1) * heads * sectors_pt < nsect)
1323 		cylinders = 0xffff;
1324 
1325 	info[0] = heads;
1326 	info[1] = sectors_pt;
1327 	info[2] = (int)cylinders;
1328 
1329 	return 0;
1330 }
1331 
1332 static int storvsc_host_reset_handler(struct scsi_cmnd *scmnd)
1333 {
1334 	struct hv_host_device *host_dev = shost_priv(scmnd->device->host);
1335 	struct hv_device *device = host_dev->dev;
1336 
1337 	struct storvsc_device *stor_device;
1338 	struct storvsc_cmd_request *request;
1339 	struct vstor_packet *vstor_packet;
1340 	int ret, t;
1341 
1342 
1343 	stor_device = get_out_stor_device(device);
1344 	if (!stor_device)
1345 		return FAILED;
1346 
1347 	request = &stor_device->reset_request;
1348 	vstor_packet = &request->vstor_packet;
1349 
1350 	init_completion(&request->wait_event);
1351 
1352 	vstor_packet->operation = VSTOR_OPERATION_RESET_BUS;
1353 	vstor_packet->flags = REQUEST_COMPLETION_FLAG;
1354 	vstor_packet->vm_srb.path_id = stor_device->path_id;
1355 
1356 	ret = vmbus_sendpacket(device->channel, vstor_packet,
1357 			       (sizeof(struct vstor_packet) -
1358 				vmscsi_size_delta),
1359 			       (unsigned long)&stor_device->reset_request,
1360 			       VM_PKT_DATA_INBAND,
1361 			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
1362 	if (ret != 0)
1363 		return FAILED;
1364 
1365 	t = wait_for_completion_timeout(&request->wait_event, 5*HZ);
1366 	if (t == 0)
1367 		return TIMEOUT_ERROR;
1368 
1369 
1370 	/*
1371 	 * At this point, all outstanding requests in the adapter
1372 	 * should have been flushed out and return to us
1373 	 * There is a potential race here where the host may be in
1374 	 * the process of responding when we return from here.
1375 	 * Just wait for all in-transit packets to be accounted for
1376 	 * before we return from here.
1377 	 */
1378 	storvsc_wait_to_drain(stor_device);
1379 
1380 	return SUCCESS;
1381 }
1382 
1383 /*
1384  * The host guarantees to respond to each command, although I/O latencies might
1385  * be unbounded on Azure.  Reset the timer unconditionally to give the host a
1386  * chance to perform EH.
1387  */
1388 static enum blk_eh_timer_return storvsc_eh_timed_out(struct scsi_cmnd *scmnd)
1389 {
1390 	return BLK_EH_RESET_TIMER;
1391 }
1392 
1393 static bool storvsc_scsi_cmd_ok(struct scsi_cmnd *scmnd)
1394 {
1395 	bool allowed = true;
1396 	u8 scsi_op = scmnd->cmnd[0];
1397 
1398 	switch (scsi_op) {
1399 	/* the host does not handle WRITE_SAME, log accident usage */
1400 	case WRITE_SAME:
1401 	/*
1402 	 * smartd sends this command and the host does not handle
1403 	 * this. So, don't send it.
1404 	 */
1405 	case SET_WINDOW:
1406 		scmnd->result = ILLEGAL_REQUEST << 16;
1407 		allowed = false;
1408 		break;
1409 	default:
1410 		break;
1411 	}
1412 	return allowed;
1413 }
1414 
1415 static int storvsc_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *scmnd)
1416 {
1417 	int ret;
1418 	struct hv_host_device *host_dev = shost_priv(host);
1419 	struct hv_device *dev = host_dev->dev;
1420 	struct storvsc_cmd_request *cmd_request = scsi_cmd_priv(scmnd);
1421 	int i;
1422 	struct scatterlist *sgl;
1423 	unsigned int sg_count = 0;
1424 	struct vmscsi_request *vm_srb;
1425 	struct scatterlist *cur_sgl;
1426 	struct vmbus_packet_mpb_array  *payload;
1427 	u32 payload_sz;
1428 	u32 length;
1429 
1430 	if (vmstor_proto_version <= VMSTOR_PROTO_VERSION_WIN8) {
1431 		/*
1432 		 * On legacy hosts filter unimplemented commands.
1433 		 * Future hosts are expected to correctly handle
1434 		 * unsupported commands. Furthermore, it is
1435 		 * possible that some of the currently
1436 		 * unsupported commands maybe supported in
1437 		 * future versions of the host.
1438 		 */
1439 		if (!storvsc_scsi_cmd_ok(scmnd)) {
1440 			scmnd->scsi_done(scmnd);
1441 			return 0;
1442 		}
1443 	}
1444 
1445 	/* Setup the cmd request */
1446 	cmd_request->cmd = scmnd;
1447 
1448 	vm_srb = &cmd_request->vstor_packet.vm_srb;
1449 	vm_srb->win8_extension.time_out_value = 60;
1450 
1451 	vm_srb->win8_extension.srb_flags |=
1452 		SRB_FLAGS_DISABLE_SYNCH_TRANSFER;
1453 
1454 	/* Build the SRB */
1455 	switch (scmnd->sc_data_direction) {
1456 	case DMA_TO_DEVICE:
1457 		vm_srb->data_in = WRITE_TYPE;
1458 		vm_srb->win8_extension.srb_flags |= SRB_FLAGS_DATA_OUT;
1459 		break;
1460 	case DMA_FROM_DEVICE:
1461 		vm_srb->data_in = READ_TYPE;
1462 		vm_srb->win8_extension.srb_flags |= SRB_FLAGS_DATA_IN;
1463 		break;
1464 	case DMA_NONE:
1465 		vm_srb->data_in = UNKNOWN_TYPE;
1466 		vm_srb->win8_extension.srb_flags |= SRB_FLAGS_NO_DATA_TRANSFER;
1467 		break;
1468 	default:
1469 		/*
1470 		 * This is DMA_BIDIRECTIONAL or something else we are never
1471 		 * supposed to see here.
1472 		 */
1473 		WARN(1, "Unexpected data direction: %d\n",
1474 		     scmnd->sc_data_direction);
1475 		return -EINVAL;
1476 	}
1477 
1478 
1479 	vm_srb->port_number = host_dev->port;
1480 	vm_srb->path_id = scmnd->device->channel;
1481 	vm_srb->target_id = scmnd->device->id;
1482 	vm_srb->lun = scmnd->device->lun;
1483 
1484 	vm_srb->cdb_length = scmnd->cmd_len;
1485 
1486 	memcpy(vm_srb->cdb, scmnd->cmnd, vm_srb->cdb_length);
1487 
1488 	sgl = (struct scatterlist *)scsi_sglist(scmnd);
1489 	sg_count = scsi_sg_count(scmnd);
1490 
1491 	length = scsi_bufflen(scmnd);
1492 	payload = (struct vmbus_packet_mpb_array *)&cmd_request->mpb;
1493 	payload_sz = sizeof(cmd_request->mpb);
1494 
1495 	if (sg_count) {
1496 		if (sg_count > MAX_PAGE_BUFFER_COUNT) {
1497 
1498 			payload_sz = (sg_count * sizeof(void *) +
1499 				      sizeof(struct vmbus_packet_mpb_array));
1500 			payload = kmalloc(payload_sz, GFP_ATOMIC);
1501 			if (!payload)
1502 				return SCSI_MLQUEUE_DEVICE_BUSY;
1503 		}
1504 
1505 		payload->range.len = length;
1506 		payload->range.offset = sgl[0].offset;
1507 
1508 		cur_sgl = sgl;
1509 		for (i = 0; i < sg_count; i++) {
1510 			payload->range.pfn_array[i] =
1511 				page_to_pfn(sg_page((cur_sgl)));
1512 			cur_sgl = sg_next(cur_sgl);
1513 		}
1514 
1515 	} else if (scsi_sglist(scmnd)) {
1516 		payload->range.len = length;
1517 		payload->range.offset =
1518 			virt_to_phys(scsi_sglist(scmnd)) & (PAGE_SIZE-1);
1519 		payload->range.pfn_array[0] =
1520 			virt_to_phys(scsi_sglist(scmnd)) >> PAGE_SHIFT;
1521 	}
1522 
1523 	cmd_request->payload = payload;
1524 	cmd_request->payload_sz = payload_sz;
1525 
1526 	/* Invokes the vsc to start an IO */
1527 	ret = storvsc_do_io(dev, cmd_request);
1528 
1529 	if (ret == -EAGAIN) {
1530 		/* no more space */
1531 		return SCSI_MLQUEUE_DEVICE_BUSY;
1532 	}
1533 
1534 	return 0;
1535 }
1536 
1537 static struct scsi_host_template scsi_driver = {
1538 	.module	=		THIS_MODULE,
1539 	.name =			"storvsc_host_t",
1540 	.cmd_size =             sizeof(struct storvsc_cmd_request),
1541 	.bios_param =		storvsc_get_chs,
1542 	.queuecommand =		storvsc_queuecommand,
1543 	.eh_host_reset_handler =	storvsc_host_reset_handler,
1544 	.proc_name =		"storvsc_host",
1545 	.eh_timed_out =		storvsc_eh_timed_out,
1546 	.slave_configure =	storvsc_device_configure,
1547 	.cmd_per_lun =		255,
1548 	.this_id =		-1,
1549 	.use_clustering =	ENABLE_CLUSTERING,
1550 	/* Make sure we dont get a sg segment crosses a page boundary */
1551 	.dma_boundary =		PAGE_SIZE-1,
1552 	.no_write_same =	1,
1553 };
1554 
1555 enum {
1556 	SCSI_GUID,
1557 	IDE_GUID,
1558 	SFC_GUID,
1559 };
1560 
1561 static const struct hv_vmbus_device_id id_table[] = {
1562 	/* SCSI guid */
1563 	{ HV_SCSI_GUID,
1564 	  .driver_data = SCSI_GUID
1565 	},
1566 	/* IDE guid */
1567 	{ HV_IDE_GUID,
1568 	  .driver_data = IDE_GUID
1569 	},
1570 	/* Fibre Channel GUID */
1571 	{
1572 	  HV_SYNTHFC_GUID,
1573 	  .driver_data = SFC_GUID
1574 	},
1575 	{ },
1576 };
1577 
1578 MODULE_DEVICE_TABLE(vmbus, id_table);
1579 
1580 static int storvsc_probe(struct hv_device *device,
1581 			const struct hv_vmbus_device_id *dev_id)
1582 {
1583 	int ret;
1584 	int num_cpus = num_online_cpus();
1585 	struct Scsi_Host *host;
1586 	struct hv_host_device *host_dev;
1587 	bool dev_is_ide = ((dev_id->driver_data == IDE_GUID) ? true : false);
1588 	bool is_fc = ((dev_id->driver_data == SFC_GUID) ? true : false);
1589 	int target = 0;
1590 	struct storvsc_device *stor_device;
1591 	int max_luns_per_target;
1592 	int max_targets;
1593 	int max_channels;
1594 	int max_sub_channels = 0;
1595 
1596 	/*
1597 	 * Based on the windows host we are running on,
1598 	 * set state to properly communicate with the host.
1599 	 */
1600 
1601 	if (vmbus_proto_version < VERSION_WIN8) {
1602 		max_luns_per_target = STORVSC_IDE_MAX_LUNS_PER_TARGET;
1603 		max_targets = STORVSC_IDE_MAX_TARGETS;
1604 		max_channels = STORVSC_IDE_MAX_CHANNELS;
1605 	} else {
1606 		max_luns_per_target = STORVSC_MAX_LUNS_PER_TARGET;
1607 		max_targets = STORVSC_MAX_TARGETS;
1608 		max_channels = STORVSC_MAX_CHANNELS;
1609 		/*
1610 		 * On Windows8 and above, we support sub-channels for storage.
1611 		 * The number of sub-channels offerred is based on the number of
1612 		 * VCPUs in the guest.
1613 		 */
1614 		max_sub_channels = (num_cpus / storvsc_vcpus_per_sub_channel);
1615 	}
1616 
1617 	scsi_driver.can_queue = (max_outstanding_req_per_channel *
1618 				 (max_sub_channels + 1));
1619 
1620 	host = scsi_host_alloc(&scsi_driver,
1621 			       sizeof(struct hv_host_device));
1622 	if (!host)
1623 		return -ENOMEM;
1624 
1625 	host_dev = shost_priv(host);
1626 	memset(host_dev, 0, sizeof(struct hv_host_device));
1627 
1628 	host_dev->port = host->host_no;
1629 	host_dev->dev = device;
1630 
1631 
1632 	stor_device = kzalloc(sizeof(struct storvsc_device), GFP_KERNEL);
1633 	if (!stor_device) {
1634 		ret = -ENOMEM;
1635 		goto err_out0;
1636 	}
1637 
1638 	stor_device->destroy = false;
1639 	stor_device->open_sub_channel = false;
1640 	init_waitqueue_head(&stor_device->waiting_to_drain);
1641 	stor_device->device = device;
1642 	stor_device->host = host;
1643 	hv_set_drvdata(device, stor_device);
1644 
1645 	stor_device->port_number = host->host_no;
1646 	ret = storvsc_connect_to_vsp(device, storvsc_ringbuffer_size, is_fc);
1647 	if (ret)
1648 		goto err_out1;
1649 
1650 	host_dev->path = stor_device->path_id;
1651 	host_dev->target = stor_device->target_id;
1652 
1653 	switch (dev_id->driver_data) {
1654 	case SFC_GUID:
1655 		host->max_lun = STORVSC_FC_MAX_LUNS_PER_TARGET;
1656 		host->max_id = STORVSC_FC_MAX_TARGETS;
1657 		host->max_channel = STORVSC_FC_MAX_CHANNELS - 1;
1658 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
1659 		host->transportt = fc_transport_template;
1660 #endif
1661 		break;
1662 
1663 	case SCSI_GUID:
1664 		host->max_lun = max_luns_per_target;
1665 		host->max_id = max_targets;
1666 		host->max_channel = max_channels - 1;
1667 		break;
1668 
1669 	default:
1670 		host->max_lun = STORVSC_IDE_MAX_LUNS_PER_TARGET;
1671 		host->max_id = STORVSC_IDE_MAX_TARGETS;
1672 		host->max_channel = STORVSC_IDE_MAX_CHANNELS - 1;
1673 		break;
1674 	}
1675 	/* max cmd length */
1676 	host->max_cmd_len = STORVSC_MAX_CMD_LEN;
1677 
1678 	/*
1679 	 * set the table size based on the info we got
1680 	 * from the host.
1681 	 */
1682 	host->sg_tablesize = (stor_device->max_transfer_bytes >> PAGE_SHIFT);
1683 
1684 	/* Register the HBA and start the scsi bus scan */
1685 	ret = scsi_add_host(host, &device->device);
1686 	if (ret != 0)
1687 		goto err_out2;
1688 
1689 	if (!dev_is_ide) {
1690 		scsi_scan_host(host);
1691 	} else {
1692 		target = (device->dev_instance.b[5] << 8 |
1693 			 device->dev_instance.b[4]);
1694 		ret = scsi_add_device(host, 0, target, 0);
1695 		if (ret) {
1696 			scsi_remove_host(host);
1697 			goto err_out2;
1698 		}
1699 	}
1700 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
1701 	if (host->transportt == fc_transport_template) {
1702 		fc_host_node_name(host) = stor_device->node_name;
1703 		fc_host_port_name(host) = stor_device->port_name;
1704 	}
1705 #endif
1706 	return 0;
1707 
1708 err_out2:
1709 	/*
1710 	 * Once we have connected with the host, we would need to
1711 	 * to invoke storvsc_dev_remove() to rollback this state and
1712 	 * this call also frees up the stor_device; hence the jump around
1713 	 * err_out1 label.
1714 	 */
1715 	storvsc_dev_remove(device);
1716 	goto err_out0;
1717 
1718 err_out1:
1719 	kfree(stor_device);
1720 
1721 err_out0:
1722 	scsi_host_put(host);
1723 	return ret;
1724 }
1725 
1726 static int storvsc_remove(struct hv_device *dev)
1727 {
1728 	struct storvsc_device *stor_device = hv_get_drvdata(dev);
1729 	struct Scsi_Host *host = stor_device->host;
1730 
1731 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
1732 	if (host->transportt == fc_transport_template)
1733 		fc_remove_host(host);
1734 #endif
1735 	scsi_remove_host(host);
1736 	storvsc_dev_remove(dev);
1737 	scsi_host_put(host);
1738 
1739 	return 0;
1740 }
1741 
1742 static struct hv_driver storvsc_drv = {
1743 	.name = KBUILD_MODNAME,
1744 	.id_table = id_table,
1745 	.probe = storvsc_probe,
1746 	.remove = storvsc_remove,
1747 };
1748 
1749 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
1750 static struct fc_function_template fc_transport_functions = {
1751 	.show_host_node_name = 1,
1752 	.show_host_port_name = 1,
1753 };
1754 #endif
1755 
1756 static int __init storvsc_drv_init(void)
1757 {
1758 	int ret;
1759 
1760 	/*
1761 	 * Divide the ring buffer data size (which is 1 page less
1762 	 * than the ring buffer size since that page is reserved for
1763 	 * the ring buffer indices) by the max request size (which is
1764 	 * vmbus_channel_packet_multipage_buffer + struct vstor_packet + u64)
1765 	 */
1766 	max_outstanding_req_per_channel =
1767 		((storvsc_ringbuffer_size - PAGE_SIZE) /
1768 		ALIGN(MAX_MULTIPAGE_BUFFER_PACKET +
1769 		sizeof(struct vstor_packet) + sizeof(u64) -
1770 		vmscsi_size_delta,
1771 		sizeof(u64)));
1772 
1773 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
1774 	fc_transport_template = fc_attach_transport(&fc_transport_functions);
1775 	if (!fc_transport_template)
1776 		return -ENODEV;
1777 
1778 	/*
1779 	 * Install Hyper-V specific timeout handler.
1780 	 */
1781 	fc_transport_template->eh_timed_out = storvsc_eh_timed_out;
1782 #endif
1783 
1784 	ret = vmbus_driver_register(&storvsc_drv);
1785 
1786 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
1787 	if (ret)
1788 		fc_release_transport(fc_transport_template);
1789 #endif
1790 
1791 	return ret;
1792 }
1793 
1794 static void __exit storvsc_drv_exit(void)
1795 {
1796 	vmbus_driver_unregister(&storvsc_drv);
1797 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
1798 	fc_release_transport(fc_transport_template);
1799 #endif
1800 }
1801 
1802 MODULE_LICENSE("GPL");
1803 MODULE_DESCRIPTION("Microsoft Hyper-V virtual storage driver");
1804 module_init(storvsc_drv_init);
1805 module_exit(storvsc_drv_exit);
1806