xref: /openbmc/linux/drivers/scsi/storvsc_drv.c (revision abfbd895)
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 
45 /*
46  * All wire protocol details (storage protocol between the guest and the host)
47  * are consolidated here.
48  *
49  * Begin protocol definitions.
50  */
51 
52 /*
53  * Version history:
54  * V1 Beta: 0.1
55  * V1 RC < 2008/1/31: 1.0
56  * V1 RC > 2008/1/31:  2.0
57  * Win7: 4.2
58  * Win8: 5.1
59  * Win8.1: 6.0
60  * Win10: 6.2
61  */
62 
63 #define VMSTOR_PROTO_VERSION(MAJOR_, MINOR_)	((((MAJOR_) & 0xff) << 8) | \
64 						(((MINOR_) & 0xff)))
65 
66 #define VMSTOR_PROTO_VERSION_WIN6	VMSTOR_PROTO_VERSION(2, 0)
67 #define VMSTOR_PROTO_VERSION_WIN7	VMSTOR_PROTO_VERSION(4, 2)
68 #define VMSTOR_PROTO_VERSION_WIN8	VMSTOR_PROTO_VERSION(5, 1)
69 #define VMSTOR_PROTO_VERSION_WIN8_1	VMSTOR_PROTO_VERSION(6, 0)
70 #define VMSTOR_PROTO_VERSION_WIN10	VMSTOR_PROTO_VERSION(6, 2)
71 
72 /*  Packet structure describing virtual storage requests. */
73 enum vstor_packet_operation {
74 	VSTOR_OPERATION_COMPLETE_IO		= 1,
75 	VSTOR_OPERATION_REMOVE_DEVICE		= 2,
76 	VSTOR_OPERATION_EXECUTE_SRB		= 3,
77 	VSTOR_OPERATION_RESET_LUN		= 4,
78 	VSTOR_OPERATION_RESET_ADAPTER		= 5,
79 	VSTOR_OPERATION_RESET_BUS		= 6,
80 	VSTOR_OPERATION_BEGIN_INITIALIZATION	= 7,
81 	VSTOR_OPERATION_END_INITIALIZATION	= 8,
82 	VSTOR_OPERATION_QUERY_PROTOCOL_VERSION	= 9,
83 	VSTOR_OPERATION_QUERY_PROPERTIES	= 10,
84 	VSTOR_OPERATION_ENUMERATE_BUS		= 11,
85 	VSTOR_OPERATION_FCHBA_DATA              = 12,
86 	VSTOR_OPERATION_CREATE_SUB_CHANNELS     = 13,
87 	VSTOR_OPERATION_MAXIMUM                 = 13
88 };
89 
90 /*
91  * WWN packet for Fibre Channel HBA
92  */
93 
94 struct hv_fc_wwn_packet {
95 	bool	primary_active;
96 	u8	reserved1;
97 	u8	reserved2;
98 	u8	primary_port_wwn[8];
99 	u8	primary_node_wwn[8];
100 	u8	secondary_port_wwn[8];
101 	u8	secondary_node_wwn[8];
102 };
103 
104 
105 
106 /*
107  * SRB Flag Bits
108  */
109 
110 #define SRB_FLAGS_QUEUE_ACTION_ENABLE		0x00000002
111 #define SRB_FLAGS_DISABLE_DISCONNECT		0x00000004
112 #define SRB_FLAGS_DISABLE_SYNCH_TRANSFER	0x00000008
113 #define SRB_FLAGS_BYPASS_FROZEN_QUEUE		0x00000010
114 #define SRB_FLAGS_DISABLE_AUTOSENSE		0x00000020
115 #define SRB_FLAGS_DATA_IN			0x00000040
116 #define SRB_FLAGS_DATA_OUT			0x00000080
117 #define SRB_FLAGS_NO_DATA_TRANSFER		0x00000000
118 #define SRB_FLAGS_UNSPECIFIED_DIRECTION	(SRB_FLAGS_DATA_IN | SRB_FLAGS_DATA_OUT)
119 #define SRB_FLAGS_NO_QUEUE_FREEZE		0x00000100
120 #define SRB_FLAGS_ADAPTER_CACHE_ENABLE		0x00000200
121 #define SRB_FLAGS_FREE_SENSE_BUFFER		0x00000400
122 
123 /*
124  * This flag indicates the request is part of the workflow for processing a D3.
125  */
126 #define SRB_FLAGS_D3_PROCESSING			0x00000800
127 #define SRB_FLAGS_IS_ACTIVE			0x00010000
128 #define SRB_FLAGS_ALLOCATED_FROM_ZONE		0x00020000
129 #define SRB_FLAGS_SGLIST_FROM_POOL		0x00040000
130 #define SRB_FLAGS_BYPASS_LOCKED_QUEUE		0x00080000
131 #define SRB_FLAGS_NO_KEEP_AWAKE			0x00100000
132 #define SRB_FLAGS_PORT_DRIVER_ALLOCSENSE	0x00200000
133 #define SRB_FLAGS_PORT_DRIVER_SENSEHASPORT	0x00400000
134 #define SRB_FLAGS_DONT_START_NEXT_PACKET	0x00800000
135 #define SRB_FLAGS_PORT_DRIVER_RESERVED		0x0F000000
136 #define SRB_FLAGS_CLASS_DRIVER_RESERVED		0xF0000000
137 
138 
139 /*
140  * Platform neutral description of a scsi request -
141  * this remains the same across the write regardless of 32/64 bit
142  * note: it's patterned off the SCSI_PASS_THROUGH structure
143  */
144 #define STORVSC_MAX_CMD_LEN			0x10
145 
146 #define POST_WIN7_STORVSC_SENSE_BUFFER_SIZE	0x14
147 #define PRE_WIN8_STORVSC_SENSE_BUFFER_SIZE	0x12
148 
149 #define STORVSC_SENSE_BUFFER_SIZE		0x14
150 #define STORVSC_MAX_BUF_LEN_WITH_PADDING	0x14
151 
152 /*
153  * Sense buffer size changed in win8; have a run-time
154  * variable to track the size we should use.  This value will
155  * likely change during protocol negotiation but it is valid
156  * to start by assuming pre-Win8.
157  */
158 static int sense_buffer_size = PRE_WIN8_STORVSC_SENSE_BUFFER_SIZE;
159 
160 /*
161  * The storage protocol version is determined during the
162  * initial exchange with the host.  It will indicate which
163  * storage functionality is available in the host.
164 */
165 static int vmstor_proto_version;
166 
167 struct vmscsi_win8_extension {
168 	/*
169 	 * The following were added in Windows 8
170 	 */
171 	u16 reserve;
172 	u8  queue_tag;
173 	u8  queue_action;
174 	u32 srb_flags;
175 	u32 time_out_value;
176 	u32 queue_sort_ey;
177 } __packed;
178 
179 struct vmscsi_request {
180 	u16 length;
181 	u8 srb_status;
182 	u8 scsi_status;
183 
184 	u8  port_number;
185 	u8  path_id;
186 	u8  target_id;
187 	u8  lun;
188 
189 	u8  cdb_length;
190 	u8  sense_info_length;
191 	u8  data_in;
192 	u8  reserved;
193 
194 	u32 data_transfer_length;
195 
196 	union {
197 		u8 cdb[STORVSC_MAX_CMD_LEN];
198 		u8 sense_data[STORVSC_SENSE_BUFFER_SIZE];
199 		u8 reserved_array[STORVSC_MAX_BUF_LEN_WITH_PADDING];
200 	};
201 	/*
202 	 * The following was added in win8.
203 	 */
204 	struct vmscsi_win8_extension win8_extension;
205 
206 } __attribute((packed));
207 
208 
209 /*
210  * The size of the vmscsi_request has changed in win8. The
211  * additional size is because of new elements added to the
212  * structure. These elements are valid only when we are talking
213  * to a win8 host.
214  * Track the correction to size we need to apply. This value
215  * will likely change during protocol negotiation but it is
216  * valid to start by assuming pre-Win8.
217  */
218 static int vmscsi_size_delta = sizeof(struct vmscsi_win8_extension);
219 
220 /*
221  * The list of storage protocols in order of preference.
222  */
223 struct vmstor_protocol {
224 	int protocol_version;
225 	int sense_buffer_size;
226 	int vmscsi_size_delta;
227 };
228 
229 
230 static const struct vmstor_protocol vmstor_protocols[] = {
231 	{
232 		VMSTOR_PROTO_VERSION_WIN10,
233 		POST_WIN7_STORVSC_SENSE_BUFFER_SIZE,
234 		0
235 	},
236 	{
237 		VMSTOR_PROTO_VERSION_WIN8_1,
238 		POST_WIN7_STORVSC_SENSE_BUFFER_SIZE,
239 		0
240 	},
241 	{
242 		VMSTOR_PROTO_VERSION_WIN8,
243 		POST_WIN7_STORVSC_SENSE_BUFFER_SIZE,
244 		0
245 	},
246 	{
247 		VMSTOR_PROTO_VERSION_WIN7,
248 		PRE_WIN8_STORVSC_SENSE_BUFFER_SIZE,
249 		sizeof(struct vmscsi_win8_extension),
250 	},
251 	{
252 		VMSTOR_PROTO_VERSION_WIN6,
253 		PRE_WIN8_STORVSC_SENSE_BUFFER_SIZE,
254 		sizeof(struct vmscsi_win8_extension),
255 	}
256 };
257 
258 
259 /*
260  * This structure is sent during the intialization phase to get the different
261  * properties of the channel.
262  */
263 
264 #define STORAGE_CHANNEL_SUPPORTS_MULTI_CHANNEL		0x1
265 
266 struct vmstorage_channel_properties {
267 	u32 reserved;
268 	u16 max_channel_cnt;
269 	u16 reserved1;
270 
271 	u32 flags;
272 	u32   max_transfer_bytes;
273 
274 	u64  reserved2;
275 } __packed;
276 
277 /*  This structure is sent during the storage protocol negotiations. */
278 struct vmstorage_protocol_version {
279 	/* Major (MSW) and minor (LSW) version numbers. */
280 	u16 major_minor;
281 
282 	/*
283 	 * Revision number is auto-incremented whenever this file is changed
284 	 * (See FILL_VMSTOR_REVISION macro above).  Mismatch does not
285 	 * definitely indicate incompatibility--but it does indicate mismatched
286 	 * builds.
287 	 * This is only used on the windows side. Just set it to 0.
288 	 */
289 	u16 revision;
290 } __packed;
291 
292 /* Channel Property Flags */
293 #define STORAGE_CHANNEL_REMOVABLE_FLAG		0x1
294 #define STORAGE_CHANNEL_EMULATED_IDE_FLAG	0x2
295 
296 struct vstor_packet {
297 	/* Requested operation type */
298 	enum vstor_packet_operation operation;
299 
300 	/*  Flags - see below for values */
301 	u32 flags;
302 
303 	/* Status of the request returned from the server side. */
304 	u32 status;
305 
306 	/* Data payload area */
307 	union {
308 		/*
309 		 * Structure used to forward SCSI commands from the
310 		 * client to the server.
311 		 */
312 		struct vmscsi_request vm_srb;
313 
314 		/* Structure used to query channel properties. */
315 		struct vmstorage_channel_properties storage_channel_properties;
316 
317 		/* Used during version negotiations. */
318 		struct vmstorage_protocol_version version;
319 
320 		/* Fibre channel address packet */
321 		struct hv_fc_wwn_packet wwn_packet;
322 
323 		/* Number of sub-channels to create */
324 		u16 sub_channel_count;
325 
326 		/* This will be the maximum of the union members */
327 		u8  buffer[0x34];
328 	};
329 } __packed;
330 
331 /*
332  * Packet Flags:
333  *
334  * This flag indicates that the server should send back a completion for this
335  * packet.
336  */
337 
338 #define REQUEST_COMPLETION_FLAG	0x1
339 
340 /* Matches Windows-end */
341 enum storvsc_request_type {
342 	WRITE_TYPE = 0,
343 	READ_TYPE,
344 	UNKNOWN_TYPE,
345 };
346 
347 /*
348  * SRB status codes and masks; a subset of the codes used here.
349  */
350 
351 #define SRB_STATUS_AUTOSENSE_VALID	0x80
352 #define SRB_STATUS_QUEUE_FROZEN		0x40
353 #define SRB_STATUS_INVALID_LUN	0x20
354 #define SRB_STATUS_SUCCESS	0x01
355 #define SRB_STATUS_ABORTED	0x02
356 #define SRB_STATUS_ERROR	0x04
357 
358 #define SRB_STATUS(status) \
359 	(status & ~(SRB_STATUS_AUTOSENSE_VALID | SRB_STATUS_QUEUE_FROZEN))
360 /*
361  * This is the end of Protocol specific defines.
362  */
363 
364 static int storvsc_ringbuffer_size = (256 * PAGE_SIZE);
365 static u32 max_outstanding_req_per_channel;
366 
367 static int storvsc_vcpus_per_sub_channel = 4;
368 
369 module_param(storvsc_ringbuffer_size, int, S_IRUGO);
370 MODULE_PARM_DESC(storvsc_ringbuffer_size, "Ring buffer size (bytes)");
371 
372 module_param(storvsc_vcpus_per_sub_channel, int, S_IRUGO);
373 MODULE_PARM_DESC(vcpus_per_sub_channel, "Ratio of VCPUs to subchannels");
374 /*
375  * Timeout in seconds for all devices managed by this driver.
376  */
377 static int storvsc_timeout = 180;
378 
379 static int msft_blist_flags = BLIST_TRY_VPD_PAGES;
380 
381 
382 static void storvsc_on_channel_callback(void *context);
383 
384 #define STORVSC_MAX_LUNS_PER_TARGET			255
385 #define STORVSC_MAX_TARGETS				2
386 #define STORVSC_MAX_CHANNELS				8
387 
388 #define STORVSC_FC_MAX_LUNS_PER_TARGET			255
389 #define STORVSC_FC_MAX_TARGETS				128
390 #define STORVSC_FC_MAX_CHANNELS				8
391 
392 #define STORVSC_IDE_MAX_LUNS_PER_TARGET			64
393 #define STORVSC_IDE_MAX_TARGETS				1
394 #define STORVSC_IDE_MAX_CHANNELS			1
395 
396 struct storvsc_cmd_request {
397 	struct scsi_cmnd *cmd;
398 
399 	struct hv_device *device;
400 
401 	/* Synchronize the request/response if needed */
402 	struct completion wait_event;
403 
404 	struct vmbus_channel_packet_multipage_buffer mpb;
405 	struct vmbus_packet_mpb_array *payload;
406 	u32 payload_sz;
407 
408 	struct vstor_packet vstor_packet;
409 };
410 
411 
412 /* A storvsc device is a device object that contains a vmbus channel */
413 struct storvsc_device {
414 	struct hv_device *device;
415 
416 	bool	 destroy;
417 	bool	 drain_notify;
418 	bool	 open_sub_channel;
419 	atomic_t num_outstanding_req;
420 	struct Scsi_Host *host;
421 
422 	wait_queue_head_t waiting_to_drain;
423 
424 	/*
425 	 * Each unique Port/Path/Target represents 1 channel ie scsi
426 	 * controller. In reality, the pathid, targetid is always 0
427 	 * and the port is set by us
428 	 */
429 	unsigned int port_number;
430 	unsigned char path_id;
431 	unsigned char target_id;
432 
433 	/*
434 	 * Max I/O, the device can support.
435 	 */
436 	u32   max_transfer_bytes;
437 	/* Used for vsc/vsp channel reset process */
438 	struct storvsc_cmd_request init_request;
439 	struct storvsc_cmd_request reset_request;
440 };
441 
442 struct hv_host_device {
443 	struct hv_device *dev;
444 	unsigned int port;
445 	unsigned char path;
446 	unsigned char target;
447 };
448 
449 struct storvsc_scan_work {
450 	struct work_struct work;
451 	struct Scsi_Host *host;
452 	uint lun;
453 };
454 
455 static void storvsc_device_scan(struct work_struct *work)
456 {
457 	struct storvsc_scan_work *wrk;
458 	uint lun;
459 	struct scsi_device *sdev;
460 
461 	wrk = container_of(work, struct storvsc_scan_work, work);
462 	lun = wrk->lun;
463 
464 	sdev = scsi_device_lookup(wrk->host, 0, 0, lun);
465 	if (!sdev)
466 		goto done;
467 	scsi_rescan_device(&sdev->sdev_gendev);
468 	scsi_device_put(sdev);
469 
470 done:
471 	kfree(wrk);
472 }
473 
474 static void storvsc_host_scan(struct work_struct *work)
475 {
476 	struct storvsc_scan_work *wrk;
477 	struct Scsi_Host *host;
478 	struct scsi_device *sdev;
479 
480 	wrk = container_of(work, struct storvsc_scan_work, work);
481 	host = wrk->host;
482 
483 	/*
484 	 * Before scanning the host, first check to see if any of the
485 	 * currrently known devices have been hot removed. We issue a
486 	 * "unit ready" command against all currently known devices.
487 	 * This I/O will result in an error for devices that have been
488 	 * removed. As part of handling the I/O error, we remove the device.
489 	 *
490 	 * When a LUN is added or removed, the host sends us a signal to
491 	 * scan the host. Thus we are forced to discover the LUNs that
492 	 * may have been removed this way.
493 	 */
494 	mutex_lock(&host->scan_mutex);
495 	shost_for_each_device(sdev, host)
496 		scsi_test_unit_ready(sdev, 1, 1, NULL);
497 	mutex_unlock(&host->scan_mutex);
498 	/*
499 	 * Now scan the host to discover LUNs that may have been added.
500 	 */
501 	scsi_scan_host(host);
502 
503 	kfree(wrk);
504 }
505 
506 static void storvsc_remove_lun(struct work_struct *work)
507 {
508 	struct storvsc_scan_work *wrk;
509 	struct scsi_device *sdev;
510 
511 	wrk = container_of(work, struct storvsc_scan_work, work);
512 	if (!scsi_host_get(wrk->host))
513 		goto done;
514 
515 	sdev = scsi_device_lookup(wrk->host, 0, 0, wrk->lun);
516 
517 	if (sdev) {
518 		scsi_remove_device(sdev);
519 		scsi_device_put(sdev);
520 	}
521 	scsi_host_put(wrk->host);
522 
523 done:
524 	kfree(wrk);
525 }
526 
527 
528 /*
529  * We can get incoming messages from the host that are not in response to
530  * messages that we have sent out. An example of this would be messages
531  * received by the guest to notify dynamic addition/removal of LUNs. To
532  * deal with potential race conditions where the driver may be in the
533  * midst of being unloaded when we might receive an unsolicited message
534  * from the host, we have implemented a mechanism to gurantee sequential
535  * consistency:
536  *
537  * 1) Once the device is marked as being destroyed, we will fail all
538  *    outgoing messages.
539  * 2) We permit incoming messages when the device is being destroyed,
540  *    only to properly account for messages already sent out.
541  */
542 
543 static inline struct storvsc_device *get_out_stor_device(
544 					struct hv_device *device)
545 {
546 	struct storvsc_device *stor_device;
547 
548 	stor_device = hv_get_drvdata(device);
549 
550 	if (stor_device && stor_device->destroy)
551 		stor_device = NULL;
552 
553 	return stor_device;
554 }
555 
556 
557 static inline void storvsc_wait_to_drain(struct storvsc_device *dev)
558 {
559 	dev->drain_notify = true;
560 	wait_event(dev->waiting_to_drain,
561 		   atomic_read(&dev->num_outstanding_req) == 0);
562 	dev->drain_notify = false;
563 }
564 
565 static inline struct storvsc_device *get_in_stor_device(
566 					struct hv_device *device)
567 {
568 	struct storvsc_device *stor_device;
569 
570 	stor_device = hv_get_drvdata(device);
571 
572 	if (!stor_device)
573 		goto get_in_err;
574 
575 	/*
576 	 * If the device is being destroyed; allow incoming
577 	 * traffic only to cleanup outstanding requests.
578 	 */
579 
580 	if (stor_device->destroy  &&
581 		(atomic_read(&stor_device->num_outstanding_req) == 0))
582 		stor_device = NULL;
583 
584 get_in_err:
585 	return stor_device;
586 
587 }
588 
589 static void handle_sc_creation(struct vmbus_channel *new_sc)
590 {
591 	struct hv_device *device = new_sc->primary_channel->device_obj;
592 	struct storvsc_device *stor_device;
593 	struct vmstorage_channel_properties props;
594 
595 	stor_device = get_out_stor_device(device);
596 	if (!stor_device)
597 		return;
598 
599 	if (stor_device->open_sub_channel == false)
600 		return;
601 
602 	memset(&props, 0, sizeof(struct vmstorage_channel_properties));
603 
604 	vmbus_open(new_sc,
605 		   storvsc_ringbuffer_size,
606 		   storvsc_ringbuffer_size,
607 		   (void *)&props,
608 		   sizeof(struct vmstorage_channel_properties),
609 		   storvsc_on_channel_callback, new_sc);
610 }
611 
612 static void  handle_multichannel_storage(struct hv_device *device, int max_chns)
613 {
614 	struct storvsc_device *stor_device;
615 	int num_cpus = num_online_cpus();
616 	int num_sc;
617 	struct storvsc_cmd_request *request;
618 	struct vstor_packet *vstor_packet;
619 	int ret, t;
620 
621 	num_sc = ((max_chns > num_cpus) ? num_cpus : max_chns);
622 	stor_device = get_out_stor_device(device);
623 	if (!stor_device)
624 		return;
625 
626 	request = &stor_device->init_request;
627 	vstor_packet = &request->vstor_packet;
628 
629 	stor_device->open_sub_channel = true;
630 	/*
631 	 * Establish a handler for dealing with subchannels.
632 	 */
633 	vmbus_set_sc_create_callback(device->channel, handle_sc_creation);
634 
635 	/*
636 	 * Check to see if sub-channels have already been created. This
637 	 * can happen when this driver is re-loaded after unloading.
638 	 */
639 
640 	if (vmbus_are_subchannels_present(device->channel))
641 		return;
642 
643 	stor_device->open_sub_channel = false;
644 	/*
645 	 * Request the host to create sub-channels.
646 	 */
647 	memset(request, 0, sizeof(struct storvsc_cmd_request));
648 	init_completion(&request->wait_event);
649 	vstor_packet->operation = VSTOR_OPERATION_CREATE_SUB_CHANNELS;
650 	vstor_packet->flags = REQUEST_COMPLETION_FLAG;
651 	vstor_packet->sub_channel_count = num_sc;
652 
653 	ret = vmbus_sendpacket(device->channel, vstor_packet,
654 			       (sizeof(struct vstor_packet) -
655 			       vmscsi_size_delta),
656 			       (unsigned long)request,
657 			       VM_PKT_DATA_INBAND,
658 			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
659 
660 	if (ret != 0)
661 		return;
662 
663 	t = wait_for_completion_timeout(&request->wait_event, 10*HZ);
664 	if (t == 0)
665 		return;
666 
667 	if (vstor_packet->operation != VSTOR_OPERATION_COMPLETE_IO ||
668 	    vstor_packet->status != 0)
669 		return;
670 
671 	/*
672 	 * Now that we created the sub-channels, invoke the check; this
673 	 * may trigger the callback.
674 	 */
675 	stor_device->open_sub_channel = true;
676 	vmbus_are_subchannels_present(device->channel);
677 }
678 
679 static int storvsc_channel_init(struct hv_device *device)
680 {
681 	struct storvsc_device *stor_device;
682 	struct storvsc_cmd_request *request;
683 	struct vstor_packet *vstor_packet;
684 	int ret, t, i;
685 	int max_chns;
686 	bool process_sub_channels = false;
687 
688 	stor_device = get_out_stor_device(device);
689 	if (!stor_device)
690 		return -ENODEV;
691 
692 	request = &stor_device->init_request;
693 	vstor_packet = &request->vstor_packet;
694 
695 	/*
696 	 * Now, initiate the vsc/vsp initialization protocol on the open
697 	 * channel
698 	 */
699 	memset(request, 0, sizeof(struct storvsc_cmd_request));
700 	init_completion(&request->wait_event);
701 	vstor_packet->operation = VSTOR_OPERATION_BEGIN_INITIALIZATION;
702 	vstor_packet->flags = REQUEST_COMPLETION_FLAG;
703 
704 	ret = vmbus_sendpacket(device->channel, vstor_packet,
705 			       (sizeof(struct vstor_packet) -
706 			       vmscsi_size_delta),
707 			       (unsigned long)request,
708 			       VM_PKT_DATA_INBAND,
709 			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
710 	if (ret != 0)
711 		goto cleanup;
712 
713 	t = wait_for_completion_timeout(&request->wait_event, 5*HZ);
714 	if (t == 0) {
715 		ret = -ETIMEDOUT;
716 		goto cleanup;
717 	}
718 
719 	if (vstor_packet->operation != VSTOR_OPERATION_COMPLETE_IO ||
720 	    vstor_packet->status != 0) {
721 		ret = -EINVAL;
722 		goto cleanup;
723 	}
724 
725 
726 	for (i = 0; i < ARRAY_SIZE(vmstor_protocols); i++) {
727 		/* reuse the packet for version range supported */
728 		memset(vstor_packet, 0, sizeof(struct vstor_packet));
729 		vstor_packet->operation =
730 			VSTOR_OPERATION_QUERY_PROTOCOL_VERSION;
731 		vstor_packet->flags = REQUEST_COMPLETION_FLAG;
732 
733 		vstor_packet->version.major_minor =
734 			vmstor_protocols[i].protocol_version;
735 
736 		/*
737 		 * The revision number is only used in Windows; set it to 0.
738 		 */
739 		vstor_packet->version.revision = 0;
740 
741 		ret = vmbus_sendpacket(device->channel, vstor_packet,
742 			       (sizeof(struct vstor_packet) -
743 				vmscsi_size_delta),
744 			       (unsigned long)request,
745 			       VM_PKT_DATA_INBAND,
746 			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
747 		if (ret != 0)
748 			goto cleanup;
749 
750 		t = wait_for_completion_timeout(&request->wait_event, 5*HZ);
751 		if (t == 0) {
752 			ret = -ETIMEDOUT;
753 			goto cleanup;
754 		}
755 
756 		if (vstor_packet->operation != VSTOR_OPERATION_COMPLETE_IO) {
757 			ret = -EINVAL;
758 			goto cleanup;
759 		}
760 
761 		if (vstor_packet->status == 0) {
762 			vmstor_proto_version =
763 				vmstor_protocols[i].protocol_version;
764 
765 			sense_buffer_size =
766 				vmstor_protocols[i].sense_buffer_size;
767 
768 			vmscsi_size_delta =
769 				vmstor_protocols[i].vmscsi_size_delta;
770 
771 			break;
772 		}
773 	}
774 
775 	if (vstor_packet->status != 0) {
776 		ret = -EINVAL;
777 		goto cleanup;
778 	}
779 
780 
781 	memset(vstor_packet, 0, sizeof(struct vstor_packet));
782 	vstor_packet->operation = VSTOR_OPERATION_QUERY_PROPERTIES;
783 	vstor_packet->flags = REQUEST_COMPLETION_FLAG;
784 
785 	ret = vmbus_sendpacket(device->channel, vstor_packet,
786 			       (sizeof(struct vstor_packet) -
787 				vmscsi_size_delta),
788 			       (unsigned long)request,
789 			       VM_PKT_DATA_INBAND,
790 			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
791 
792 	if (ret != 0)
793 		goto cleanup;
794 
795 	t = wait_for_completion_timeout(&request->wait_event, 5*HZ);
796 	if (t == 0) {
797 		ret = -ETIMEDOUT;
798 		goto cleanup;
799 	}
800 
801 	if (vstor_packet->operation != VSTOR_OPERATION_COMPLETE_IO ||
802 	    vstor_packet->status != 0) {
803 		ret = -EINVAL;
804 		goto cleanup;
805 	}
806 
807 	/*
808 	 * Check to see if multi-channel support is there.
809 	 * Hosts that implement protocol version of 5.1 and above
810 	 * support multi-channel.
811 	 */
812 	max_chns = vstor_packet->storage_channel_properties.max_channel_cnt;
813 	if (vmstor_proto_version >= VMSTOR_PROTO_VERSION_WIN8) {
814 		if (vstor_packet->storage_channel_properties.flags &
815 		    STORAGE_CHANNEL_SUPPORTS_MULTI_CHANNEL)
816 			process_sub_channels = true;
817 	}
818 	stor_device->max_transfer_bytes =
819 		vstor_packet->storage_channel_properties.max_transfer_bytes;
820 
821 	memset(vstor_packet, 0, sizeof(struct vstor_packet));
822 	vstor_packet->operation = VSTOR_OPERATION_END_INITIALIZATION;
823 	vstor_packet->flags = REQUEST_COMPLETION_FLAG;
824 
825 	ret = vmbus_sendpacket(device->channel, vstor_packet,
826 			       (sizeof(struct vstor_packet) -
827 				vmscsi_size_delta),
828 			       (unsigned long)request,
829 			       VM_PKT_DATA_INBAND,
830 			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
831 
832 	if (ret != 0)
833 		goto cleanup;
834 
835 	t = wait_for_completion_timeout(&request->wait_event, 5*HZ);
836 	if (t == 0) {
837 		ret = -ETIMEDOUT;
838 		goto cleanup;
839 	}
840 
841 	if (vstor_packet->operation != VSTOR_OPERATION_COMPLETE_IO ||
842 	    vstor_packet->status != 0) {
843 		ret = -EINVAL;
844 		goto cleanup;
845 	}
846 
847 	if (process_sub_channels)
848 		handle_multichannel_storage(device, max_chns);
849 
850 
851 cleanup:
852 	return ret;
853 }
854 
855 static void storvsc_handle_error(struct vmscsi_request *vm_srb,
856 				struct scsi_cmnd *scmnd,
857 				struct Scsi_Host *host,
858 				u8 asc, u8 ascq)
859 {
860 	struct storvsc_scan_work *wrk;
861 	void (*process_err_fn)(struct work_struct *work);
862 	bool do_work = false;
863 
864 	switch (SRB_STATUS(vm_srb->srb_status)) {
865 	case SRB_STATUS_ERROR:
866 		/*
867 		 * If there is an error; offline the device since all
868 		 * error recovery strategies would have already been
869 		 * deployed on the host side. However, if the command
870 		 * were a pass-through command deal with it appropriately.
871 		 */
872 		switch (scmnd->cmnd[0]) {
873 		case ATA_16:
874 		case ATA_12:
875 			set_host_byte(scmnd, DID_PASSTHROUGH);
876 			break;
877 		/*
878 		 * On Some Windows hosts TEST_UNIT_READY command can return
879 		 * SRB_STATUS_ERROR, let the upper level code deal with it
880 		 * based on the sense information.
881 		 */
882 		case TEST_UNIT_READY:
883 			break;
884 		default:
885 			set_host_byte(scmnd, DID_TARGET_FAILURE);
886 		}
887 		break;
888 	case SRB_STATUS_INVALID_LUN:
889 		do_work = true;
890 		process_err_fn = storvsc_remove_lun;
891 		break;
892 	case (SRB_STATUS_ABORTED | SRB_STATUS_AUTOSENSE_VALID):
893 		if ((asc == 0x2a) && (ascq == 0x9)) {
894 			do_work = true;
895 			process_err_fn = storvsc_device_scan;
896 			/*
897 			 * Retry the I/O that trigerred this.
898 			 */
899 			set_host_byte(scmnd, DID_REQUEUE);
900 		}
901 		break;
902 	}
903 
904 	if (!do_work)
905 		return;
906 
907 	/*
908 	 * We need to schedule work to process this error; schedule it.
909 	 */
910 	wrk = kmalloc(sizeof(struct storvsc_scan_work), GFP_ATOMIC);
911 	if (!wrk) {
912 		set_host_byte(scmnd, DID_TARGET_FAILURE);
913 		return;
914 	}
915 
916 	wrk->host = host;
917 	wrk->lun = vm_srb->lun;
918 	INIT_WORK(&wrk->work, process_err_fn);
919 	schedule_work(&wrk->work);
920 }
921 
922 
923 static void storvsc_command_completion(struct storvsc_cmd_request *cmd_request)
924 {
925 	struct scsi_cmnd *scmnd = cmd_request->cmd;
926 	struct hv_host_device *host_dev = shost_priv(scmnd->device->host);
927 	struct scsi_sense_hdr sense_hdr;
928 	struct vmscsi_request *vm_srb;
929 	struct Scsi_Host *host;
930 	struct storvsc_device *stor_dev;
931 	struct hv_device *dev = host_dev->dev;
932 	u32 payload_sz = cmd_request->payload_sz;
933 	void *payload = cmd_request->payload;
934 
935 	stor_dev = get_in_stor_device(dev);
936 	host = stor_dev->host;
937 
938 	vm_srb = &cmd_request->vstor_packet.vm_srb;
939 
940 	scmnd->result = vm_srb->scsi_status;
941 
942 	if (scmnd->result) {
943 		if (scsi_normalize_sense(scmnd->sense_buffer,
944 				SCSI_SENSE_BUFFERSIZE, &sense_hdr))
945 			scsi_print_sense_hdr(scmnd->device, "storvsc",
946 					     &sense_hdr);
947 	}
948 
949 	if (vm_srb->srb_status != SRB_STATUS_SUCCESS)
950 		storvsc_handle_error(vm_srb, scmnd, host, sense_hdr.asc,
951 					 sense_hdr.ascq);
952 
953 	scsi_set_resid(scmnd,
954 		cmd_request->payload->range.len -
955 		vm_srb->data_transfer_length);
956 
957 	scmnd->scsi_done(scmnd);
958 
959 	if (payload_sz >
960 		sizeof(struct vmbus_channel_packet_multipage_buffer))
961 		kfree(payload);
962 }
963 
964 static void storvsc_on_io_completion(struct hv_device *device,
965 				  struct vstor_packet *vstor_packet,
966 				  struct storvsc_cmd_request *request)
967 {
968 	struct storvsc_device *stor_device;
969 	struct vstor_packet *stor_pkt;
970 
971 	stor_device = hv_get_drvdata(device);
972 	stor_pkt = &request->vstor_packet;
973 
974 	/*
975 	 * The current SCSI handling on the host side does
976 	 * not correctly handle:
977 	 * INQUIRY command with page code parameter set to 0x80
978 	 * MODE_SENSE command with cmd[2] == 0x1c
979 	 *
980 	 * Setup srb and scsi status so this won't be fatal.
981 	 * We do this so we can distinguish truly fatal failues
982 	 * (srb status == 0x4) and off-line the device in that case.
983 	 */
984 
985 	if ((stor_pkt->vm_srb.cdb[0] == INQUIRY) ||
986 	   (stor_pkt->vm_srb.cdb[0] == MODE_SENSE)) {
987 		vstor_packet->vm_srb.scsi_status = 0;
988 		vstor_packet->vm_srb.srb_status = SRB_STATUS_SUCCESS;
989 	}
990 
991 
992 	/* Copy over the status...etc */
993 	stor_pkt->vm_srb.scsi_status = vstor_packet->vm_srb.scsi_status;
994 	stor_pkt->vm_srb.srb_status = vstor_packet->vm_srb.srb_status;
995 	stor_pkt->vm_srb.sense_info_length =
996 	vstor_packet->vm_srb.sense_info_length;
997 
998 
999 	if ((vstor_packet->vm_srb.scsi_status & 0xFF) == 0x02) {
1000 		/* CHECK_CONDITION */
1001 		if (vstor_packet->vm_srb.srb_status &
1002 			SRB_STATUS_AUTOSENSE_VALID) {
1003 			/* autosense data available */
1004 
1005 			memcpy(request->cmd->sense_buffer,
1006 			       vstor_packet->vm_srb.sense_data,
1007 			       vstor_packet->vm_srb.sense_info_length);
1008 
1009 		}
1010 	}
1011 
1012 	stor_pkt->vm_srb.data_transfer_length =
1013 	vstor_packet->vm_srb.data_transfer_length;
1014 
1015 	storvsc_command_completion(request);
1016 
1017 	if (atomic_dec_and_test(&stor_device->num_outstanding_req) &&
1018 		stor_device->drain_notify)
1019 		wake_up(&stor_device->waiting_to_drain);
1020 
1021 
1022 }
1023 
1024 static void storvsc_on_receive(struct hv_device *device,
1025 			     struct vstor_packet *vstor_packet,
1026 			     struct storvsc_cmd_request *request)
1027 {
1028 	struct storvsc_scan_work *work;
1029 	struct storvsc_device *stor_device;
1030 
1031 	switch (vstor_packet->operation) {
1032 	case VSTOR_OPERATION_COMPLETE_IO:
1033 		storvsc_on_io_completion(device, vstor_packet, request);
1034 		break;
1035 
1036 	case VSTOR_OPERATION_REMOVE_DEVICE:
1037 	case VSTOR_OPERATION_ENUMERATE_BUS:
1038 		stor_device = get_in_stor_device(device);
1039 		work = kmalloc(sizeof(struct storvsc_scan_work), GFP_ATOMIC);
1040 		if (!work)
1041 			return;
1042 
1043 		INIT_WORK(&work->work, storvsc_host_scan);
1044 		work->host = stor_device->host;
1045 		schedule_work(&work->work);
1046 		break;
1047 
1048 	default:
1049 		break;
1050 	}
1051 }
1052 
1053 static void storvsc_on_channel_callback(void *context)
1054 {
1055 	struct vmbus_channel *channel = (struct vmbus_channel *)context;
1056 	struct hv_device *device;
1057 	struct storvsc_device *stor_device;
1058 	u32 bytes_recvd;
1059 	u64 request_id;
1060 	unsigned char packet[ALIGN(sizeof(struct vstor_packet), 8)];
1061 	struct storvsc_cmd_request *request;
1062 	int ret;
1063 
1064 	if (channel->primary_channel != NULL)
1065 		device = channel->primary_channel->device_obj;
1066 	else
1067 		device = channel->device_obj;
1068 
1069 	stor_device = get_in_stor_device(device);
1070 	if (!stor_device)
1071 		return;
1072 
1073 	do {
1074 		ret = vmbus_recvpacket(channel, packet,
1075 				       ALIGN((sizeof(struct vstor_packet) -
1076 					     vmscsi_size_delta), 8),
1077 				       &bytes_recvd, &request_id);
1078 		if (ret == 0 && bytes_recvd > 0) {
1079 
1080 			request = (struct storvsc_cmd_request *)
1081 					(unsigned long)request_id;
1082 
1083 			if ((request == &stor_device->init_request) ||
1084 			    (request == &stor_device->reset_request)) {
1085 
1086 				memcpy(&request->vstor_packet, packet,
1087 				       (sizeof(struct vstor_packet) -
1088 					vmscsi_size_delta));
1089 				complete(&request->wait_event);
1090 			} else {
1091 				storvsc_on_receive(device,
1092 						(struct vstor_packet *)packet,
1093 						request);
1094 			}
1095 		} else {
1096 			break;
1097 		}
1098 	} while (1);
1099 
1100 	return;
1101 }
1102 
1103 static int storvsc_connect_to_vsp(struct hv_device *device, u32 ring_size)
1104 {
1105 	struct vmstorage_channel_properties props;
1106 	int ret;
1107 
1108 	memset(&props, 0, sizeof(struct vmstorage_channel_properties));
1109 
1110 	ret = vmbus_open(device->channel,
1111 			 ring_size,
1112 			 ring_size,
1113 			 (void *)&props,
1114 			 sizeof(struct vmstorage_channel_properties),
1115 			 storvsc_on_channel_callback, device->channel);
1116 
1117 	if (ret != 0)
1118 		return ret;
1119 
1120 	ret = storvsc_channel_init(device);
1121 
1122 	return ret;
1123 }
1124 
1125 static int storvsc_dev_remove(struct hv_device *device)
1126 {
1127 	struct storvsc_device *stor_device;
1128 	unsigned long flags;
1129 
1130 	stor_device = hv_get_drvdata(device);
1131 
1132 	spin_lock_irqsave(&device->channel->inbound_lock, flags);
1133 	stor_device->destroy = true;
1134 	spin_unlock_irqrestore(&device->channel->inbound_lock, flags);
1135 
1136 	/*
1137 	 * At this point, all outbound traffic should be disable. We
1138 	 * only allow inbound traffic (responses) to proceed so that
1139 	 * outstanding requests can be completed.
1140 	 */
1141 
1142 	storvsc_wait_to_drain(stor_device);
1143 
1144 	/*
1145 	 * Since we have already drained, we don't need to busy wait
1146 	 * as was done in final_release_stor_device()
1147 	 * Note that we cannot set the ext pointer to NULL until
1148 	 * we have drained - to drain the outgoing packets, we need to
1149 	 * allow incoming packets.
1150 	 */
1151 	spin_lock_irqsave(&device->channel->inbound_lock, flags);
1152 	hv_set_drvdata(device, NULL);
1153 	spin_unlock_irqrestore(&device->channel->inbound_lock, flags);
1154 
1155 	/* Close the channel */
1156 	vmbus_close(device->channel);
1157 
1158 	kfree(stor_device);
1159 	return 0;
1160 }
1161 
1162 static int storvsc_do_io(struct hv_device *device,
1163 			 struct storvsc_cmd_request *request)
1164 {
1165 	struct storvsc_device *stor_device;
1166 	struct vstor_packet *vstor_packet;
1167 	struct vmbus_channel *outgoing_channel;
1168 	int ret = 0;
1169 
1170 	vstor_packet = &request->vstor_packet;
1171 	stor_device = get_out_stor_device(device);
1172 
1173 	if (!stor_device)
1174 		return -ENODEV;
1175 
1176 
1177 	request->device  = device;
1178 	/*
1179 	 * Select an an appropriate channel to send the request out.
1180 	 */
1181 
1182 	outgoing_channel = vmbus_get_outgoing_channel(device->channel);
1183 
1184 
1185 	vstor_packet->flags |= REQUEST_COMPLETION_FLAG;
1186 
1187 	vstor_packet->vm_srb.length = (sizeof(struct vmscsi_request) -
1188 					vmscsi_size_delta);
1189 
1190 
1191 	vstor_packet->vm_srb.sense_info_length = sense_buffer_size;
1192 
1193 
1194 	vstor_packet->vm_srb.data_transfer_length =
1195 	request->payload->range.len;
1196 
1197 	vstor_packet->operation = VSTOR_OPERATION_EXECUTE_SRB;
1198 
1199 	if (request->payload->range.len) {
1200 
1201 		ret = vmbus_sendpacket_mpb_desc(outgoing_channel,
1202 				request->payload, request->payload_sz,
1203 				vstor_packet,
1204 				(sizeof(struct vstor_packet) -
1205 				vmscsi_size_delta),
1206 				(unsigned long)request);
1207 	} else {
1208 		ret = vmbus_sendpacket(outgoing_channel, vstor_packet,
1209 			       (sizeof(struct vstor_packet) -
1210 				vmscsi_size_delta),
1211 			       (unsigned long)request,
1212 			       VM_PKT_DATA_INBAND,
1213 			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
1214 	}
1215 
1216 	if (ret != 0)
1217 		return ret;
1218 
1219 	atomic_inc(&stor_device->num_outstanding_req);
1220 
1221 	return ret;
1222 }
1223 
1224 static int storvsc_device_configure(struct scsi_device *sdevice)
1225 {
1226 
1227 	blk_queue_max_segment_size(sdevice->request_queue, PAGE_SIZE);
1228 
1229 	blk_queue_bounce_limit(sdevice->request_queue, BLK_BOUNCE_ANY);
1230 
1231 	blk_queue_rq_timeout(sdevice->request_queue, (storvsc_timeout * HZ));
1232 
1233 	/* Ensure there are no gaps in presented sgls */
1234 	blk_queue_virt_boundary(sdevice->request_queue, PAGE_SIZE - 1);
1235 
1236 	sdevice->no_write_same = 1;
1237 
1238 	/*
1239 	 * Add blist flags to permit the reading of the VPD pages even when
1240 	 * the target may claim SPC-2 compliance. MSFT targets currently
1241 	 * claim SPC-2 compliance while they implement post SPC-2 features.
1242 	 * With this patch we can correctly handle WRITE_SAME_16 issues.
1243 	 */
1244 	sdevice->sdev_bflags |= msft_blist_flags;
1245 
1246 	/*
1247 	 * If the host is WIN8 or WIN8 R2, claim conformance to SPC-3
1248 	 * if the device is a MSFT virtual device.  If the host is
1249 	 * WIN10 or newer, allow write_same.
1250 	 */
1251 	if (!strncmp(sdevice->vendor, "Msft", 4)) {
1252 		switch (vmstor_proto_version) {
1253 		case VMSTOR_PROTO_VERSION_WIN8:
1254 		case VMSTOR_PROTO_VERSION_WIN8_1:
1255 			sdevice->scsi_level = SCSI_SPC_3;
1256 			break;
1257 		}
1258 
1259 		if (vmstor_proto_version >= VMSTOR_PROTO_VERSION_WIN10)
1260 			sdevice->no_write_same = 0;
1261 	}
1262 
1263 	return 0;
1264 }
1265 
1266 static int storvsc_get_chs(struct scsi_device *sdev, struct block_device * bdev,
1267 			   sector_t capacity, int *info)
1268 {
1269 	sector_t nsect = capacity;
1270 	sector_t cylinders = nsect;
1271 	int heads, sectors_pt;
1272 
1273 	/*
1274 	 * We are making up these values; let us keep it simple.
1275 	 */
1276 	heads = 0xff;
1277 	sectors_pt = 0x3f;      /* Sectors per track */
1278 	sector_div(cylinders, heads * sectors_pt);
1279 	if ((sector_t)(cylinders + 1) * heads * sectors_pt < nsect)
1280 		cylinders = 0xffff;
1281 
1282 	info[0] = heads;
1283 	info[1] = sectors_pt;
1284 	info[2] = (int)cylinders;
1285 
1286 	return 0;
1287 }
1288 
1289 static int storvsc_host_reset_handler(struct scsi_cmnd *scmnd)
1290 {
1291 	struct hv_host_device *host_dev = shost_priv(scmnd->device->host);
1292 	struct hv_device *device = host_dev->dev;
1293 
1294 	struct storvsc_device *stor_device;
1295 	struct storvsc_cmd_request *request;
1296 	struct vstor_packet *vstor_packet;
1297 	int ret, t;
1298 
1299 
1300 	stor_device = get_out_stor_device(device);
1301 	if (!stor_device)
1302 		return FAILED;
1303 
1304 	request = &stor_device->reset_request;
1305 	vstor_packet = &request->vstor_packet;
1306 
1307 	init_completion(&request->wait_event);
1308 
1309 	vstor_packet->operation = VSTOR_OPERATION_RESET_BUS;
1310 	vstor_packet->flags = REQUEST_COMPLETION_FLAG;
1311 	vstor_packet->vm_srb.path_id = stor_device->path_id;
1312 
1313 	ret = vmbus_sendpacket(device->channel, vstor_packet,
1314 			       (sizeof(struct vstor_packet) -
1315 				vmscsi_size_delta),
1316 			       (unsigned long)&stor_device->reset_request,
1317 			       VM_PKT_DATA_INBAND,
1318 			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
1319 	if (ret != 0)
1320 		return FAILED;
1321 
1322 	t = wait_for_completion_timeout(&request->wait_event, 5*HZ);
1323 	if (t == 0)
1324 		return TIMEOUT_ERROR;
1325 
1326 
1327 	/*
1328 	 * At this point, all outstanding requests in the adapter
1329 	 * should have been flushed out and return to us
1330 	 * There is a potential race here where the host may be in
1331 	 * the process of responding when we return from here.
1332 	 * Just wait for all in-transit packets to be accounted for
1333 	 * before we return from here.
1334 	 */
1335 	storvsc_wait_to_drain(stor_device);
1336 
1337 	return SUCCESS;
1338 }
1339 
1340 /*
1341  * The host guarantees to respond to each command, although I/O latencies might
1342  * be unbounded on Azure.  Reset the timer unconditionally to give the host a
1343  * chance to perform EH.
1344  */
1345 static enum blk_eh_timer_return storvsc_eh_timed_out(struct scsi_cmnd *scmnd)
1346 {
1347 	return BLK_EH_RESET_TIMER;
1348 }
1349 
1350 static bool storvsc_scsi_cmd_ok(struct scsi_cmnd *scmnd)
1351 {
1352 	bool allowed = true;
1353 	u8 scsi_op = scmnd->cmnd[0];
1354 
1355 	switch (scsi_op) {
1356 	/* the host does not handle WRITE_SAME, log accident usage */
1357 	case WRITE_SAME:
1358 	/*
1359 	 * smartd sends this command and the host does not handle
1360 	 * this. So, don't send it.
1361 	 */
1362 	case SET_WINDOW:
1363 		scmnd->result = ILLEGAL_REQUEST << 16;
1364 		allowed = false;
1365 		break;
1366 	default:
1367 		break;
1368 	}
1369 	return allowed;
1370 }
1371 
1372 static int storvsc_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *scmnd)
1373 {
1374 	int ret;
1375 	struct hv_host_device *host_dev = shost_priv(host);
1376 	struct hv_device *dev = host_dev->dev;
1377 	struct storvsc_cmd_request *cmd_request = scsi_cmd_priv(scmnd);
1378 	int i;
1379 	struct scatterlist *sgl;
1380 	unsigned int sg_count = 0;
1381 	struct vmscsi_request *vm_srb;
1382 	struct scatterlist *cur_sgl;
1383 	struct vmbus_packet_mpb_array  *payload;
1384 	u32 payload_sz;
1385 	u32 length;
1386 
1387 	if (vmstor_proto_version <= VMSTOR_PROTO_VERSION_WIN8) {
1388 		/*
1389 		 * On legacy hosts filter unimplemented commands.
1390 		 * Future hosts are expected to correctly handle
1391 		 * unsupported commands. Furthermore, it is
1392 		 * possible that some of the currently
1393 		 * unsupported commands maybe supported in
1394 		 * future versions of the host.
1395 		 */
1396 		if (!storvsc_scsi_cmd_ok(scmnd)) {
1397 			scmnd->scsi_done(scmnd);
1398 			return 0;
1399 		}
1400 	}
1401 
1402 	/* Setup the cmd request */
1403 	cmd_request->cmd = scmnd;
1404 
1405 	vm_srb = &cmd_request->vstor_packet.vm_srb;
1406 	vm_srb->win8_extension.time_out_value = 60;
1407 
1408 	vm_srb->win8_extension.srb_flags |=
1409 		SRB_FLAGS_DISABLE_SYNCH_TRANSFER;
1410 
1411 	/* Build the SRB */
1412 	switch (scmnd->sc_data_direction) {
1413 	case DMA_TO_DEVICE:
1414 		vm_srb->data_in = WRITE_TYPE;
1415 		vm_srb->win8_extension.srb_flags |= SRB_FLAGS_DATA_OUT;
1416 		break;
1417 	case DMA_FROM_DEVICE:
1418 		vm_srb->data_in = READ_TYPE;
1419 		vm_srb->win8_extension.srb_flags |= SRB_FLAGS_DATA_IN;
1420 		break;
1421 	case DMA_NONE:
1422 		vm_srb->data_in = UNKNOWN_TYPE;
1423 		vm_srb->win8_extension.srb_flags |= SRB_FLAGS_NO_DATA_TRANSFER;
1424 		break;
1425 	default:
1426 		/*
1427 		 * This is DMA_BIDIRECTIONAL or something else we are never
1428 		 * supposed to see here.
1429 		 */
1430 		WARN(1, "Unexpected data direction: %d\n",
1431 		     scmnd->sc_data_direction);
1432 		return -EINVAL;
1433 	}
1434 
1435 
1436 	vm_srb->port_number = host_dev->port;
1437 	vm_srb->path_id = scmnd->device->channel;
1438 	vm_srb->target_id = scmnd->device->id;
1439 	vm_srb->lun = scmnd->device->lun;
1440 
1441 	vm_srb->cdb_length = scmnd->cmd_len;
1442 
1443 	memcpy(vm_srb->cdb, scmnd->cmnd, vm_srb->cdb_length);
1444 
1445 	sgl = (struct scatterlist *)scsi_sglist(scmnd);
1446 	sg_count = scsi_sg_count(scmnd);
1447 
1448 	length = scsi_bufflen(scmnd);
1449 	payload = (struct vmbus_packet_mpb_array *)&cmd_request->mpb;
1450 	payload_sz = sizeof(cmd_request->mpb);
1451 
1452 	if (sg_count) {
1453 		if (sg_count > MAX_PAGE_BUFFER_COUNT) {
1454 
1455 			payload_sz = (sg_count * sizeof(void *) +
1456 				      sizeof(struct vmbus_packet_mpb_array));
1457 			payload = kmalloc(payload_sz, GFP_ATOMIC);
1458 			if (!payload)
1459 				return SCSI_MLQUEUE_DEVICE_BUSY;
1460 		}
1461 
1462 		payload->range.len = length;
1463 		payload->range.offset = sgl[0].offset;
1464 
1465 		cur_sgl = sgl;
1466 		for (i = 0; i < sg_count; i++) {
1467 			payload->range.pfn_array[i] =
1468 				page_to_pfn(sg_page((cur_sgl)));
1469 			cur_sgl = sg_next(cur_sgl);
1470 		}
1471 
1472 	} else if (scsi_sglist(scmnd)) {
1473 		payload->range.len = length;
1474 		payload->range.offset =
1475 			virt_to_phys(scsi_sglist(scmnd)) & (PAGE_SIZE-1);
1476 		payload->range.pfn_array[0] =
1477 			virt_to_phys(scsi_sglist(scmnd)) >> PAGE_SHIFT;
1478 	}
1479 
1480 	cmd_request->payload = payload;
1481 	cmd_request->payload_sz = payload_sz;
1482 
1483 	/* Invokes the vsc to start an IO */
1484 	ret = storvsc_do_io(dev, cmd_request);
1485 
1486 	if (ret == -EAGAIN) {
1487 		/* no more space */
1488 		return SCSI_MLQUEUE_DEVICE_BUSY;
1489 	}
1490 
1491 	return 0;
1492 }
1493 
1494 static struct scsi_host_template scsi_driver = {
1495 	.module	=		THIS_MODULE,
1496 	.name =			"storvsc_host_t",
1497 	.cmd_size =             sizeof(struct storvsc_cmd_request),
1498 	.bios_param =		storvsc_get_chs,
1499 	.queuecommand =		storvsc_queuecommand,
1500 	.eh_host_reset_handler =	storvsc_host_reset_handler,
1501 	.proc_name =		"storvsc_host",
1502 	.eh_timed_out =		storvsc_eh_timed_out,
1503 	.slave_configure =	storvsc_device_configure,
1504 	.cmd_per_lun =		255,
1505 	.this_id =		-1,
1506 	.use_clustering =	ENABLE_CLUSTERING,
1507 	/* Make sure we dont get a sg segment crosses a page boundary */
1508 	.dma_boundary =		PAGE_SIZE-1,
1509 	.no_write_same =	1,
1510 };
1511 
1512 enum {
1513 	SCSI_GUID,
1514 	IDE_GUID,
1515 	SFC_GUID,
1516 };
1517 
1518 static const struct hv_vmbus_device_id id_table[] = {
1519 	/* SCSI guid */
1520 	{ HV_SCSI_GUID,
1521 	  .driver_data = SCSI_GUID
1522 	},
1523 	/* IDE guid */
1524 	{ HV_IDE_GUID,
1525 	  .driver_data = IDE_GUID
1526 	},
1527 	/* Fibre Channel GUID */
1528 	{
1529 	  HV_SYNTHFC_GUID,
1530 	  .driver_data = SFC_GUID
1531 	},
1532 	{ },
1533 };
1534 
1535 MODULE_DEVICE_TABLE(vmbus, id_table);
1536 
1537 static int storvsc_probe(struct hv_device *device,
1538 			const struct hv_vmbus_device_id *dev_id)
1539 {
1540 	int ret;
1541 	int num_cpus = num_online_cpus();
1542 	struct Scsi_Host *host;
1543 	struct hv_host_device *host_dev;
1544 	bool dev_is_ide = ((dev_id->driver_data == IDE_GUID) ? true : false);
1545 	int target = 0;
1546 	struct storvsc_device *stor_device;
1547 	int max_luns_per_target;
1548 	int max_targets;
1549 	int max_channels;
1550 	int max_sub_channels = 0;
1551 
1552 	/*
1553 	 * Based on the windows host we are running on,
1554 	 * set state to properly communicate with the host.
1555 	 */
1556 
1557 	if (vmbus_proto_version < VERSION_WIN8) {
1558 		max_luns_per_target = STORVSC_IDE_MAX_LUNS_PER_TARGET;
1559 		max_targets = STORVSC_IDE_MAX_TARGETS;
1560 		max_channels = STORVSC_IDE_MAX_CHANNELS;
1561 	} else {
1562 		max_luns_per_target = STORVSC_MAX_LUNS_PER_TARGET;
1563 		max_targets = STORVSC_MAX_TARGETS;
1564 		max_channels = STORVSC_MAX_CHANNELS;
1565 		/*
1566 		 * On Windows8 and above, we support sub-channels for storage.
1567 		 * The number of sub-channels offerred is based on the number of
1568 		 * VCPUs in the guest.
1569 		 */
1570 		max_sub_channels = (num_cpus / storvsc_vcpus_per_sub_channel);
1571 	}
1572 
1573 	scsi_driver.can_queue = (max_outstanding_req_per_channel *
1574 				 (max_sub_channels + 1));
1575 
1576 	host = scsi_host_alloc(&scsi_driver,
1577 			       sizeof(struct hv_host_device));
1578 	if (!host)
1579 		return -ENOMEM;
1580 
1581 	host_dev = shost_priv(host);
1582 	memset(host_dev, 0, sizeof(struct hv_host_device));
1583 
1584 	host_dev->port = host->host_no;
1585 	host_dev->dev = device;
1586 
1587 
1588 	stor_device = kzalloc(sizeof(struct storvsc_device), GFP_KERNEL);
1589 	if (!stor_device) {
1590 		ret = -ENOMEM;
1591 		goto err_out0;
1592 	}
1593 
1594 	stor_device->destroy = false;
1595 	stor_device->open_sub_channel = false;
1596 	init_waitqueue_head(&stor_device->waiting_to_drain);
1597 	stor_device->device = device;
1598 	stor_device->host = host;
1599 	hv_set_drvdata(device, stor_device);
1600 
1601 	stor_device->port_number = host->host_no;
1602 	ret = storvsc_connect_to_vsp(device, storvsc_ringbuffer_size);
1603 	if (ret)
1604 		goto err_out1;
1605 
1606 	host_dev->path = stor_device->path_id;
1607 	host_dev->target = stor_device->target_id;
1608 
1609 	switch (dev_id->driver_data) {
1610 	case SFC_GUID:
1611 		host->max_lun = STORVSC_FC_MAX_LUNS_PER_TARGET;
1612 		host->max_id = STORVSC_FC_MAX_TARGETS;
1613 		host->max_channel = STORVSC_FC_MAX_CHANNELS - 1;
1614 		break;
1615 
1616 	case SCSI_GUID:
1617 		host->max_lun = max_luns_per_target;
1618 		host->max_id = max_targets;
1619 		host->max_channel = max_channels - 1;
1620 		break;
1621 
1622 	default:
1623 		host->max_lun = STORVSC_IDE_MAX_LUNS_PER_TARGET;
1624 		host->max_id = STORVSC_IDE_MAX_TARGETS;
1625 		host->max_channel = STORVSC_IDE_MAX_CHANNELS - 1;
1626 		break;
1627 	}
1628 	/* max cmd length */
1629 	host->max_cmd_len = STORVSC_MAX_CMD_LEN;
1630 
1631 	/*
1632 	 * set the table size based on the info we got
1633 	 * from the host.
1634 	 */
1635 	host->sg_tablesize = (stor_device->max_transfer_bytes >> PAGE_SHIFT);
1636 
1637 	/* Register the HBA and start the scsi bus scan */
1638 	ret = scsi_add_host(host, &device->device);
1639 	if (ret != 0)
1640 		goto err_out2;
1641 
1642 	if (!dev_is_ide) {
1643 		scsi_scan_host(host);
1644 	} else {
1645 		target = (device->dev_instance.b[5] << 8 |
1646 			 device->dev_instance.b[4]);
1647 		ret = scsi_add_device(host, 0, target, 0);
1648 		if (ret) {
1649 			scsi_remove_host(host);
1650 			goto err_out2;
1651 		}
1652 	}
1653 	return 0;
1654 
1655 err_out2:
1656 	/*
1657 	 * Once we have connected with the host, we would need to
1658 	 * to invoke storvsc_dev_remove() to rollback this state and
1659 	 * this call also frees up the stor_device; hence the jump around
1660 	 * err_out1 label.
1661 	 */
1662 	storvsc_dev_remove(device);
1663 	goto err_out0;
1664 
1665 err_out1:
1666 	kfree(stor_device);
1667 
1668 err_out0:
1669 	scsi_host_put(host);
1670 	return ret;
1671 }
1672 
1673 static int storvsc_remove(struct hv_device *dev)
1674 {
1675 	struct storvsc_device *stor_device = hv_get_drvdata(dev);
1676 	struct Scsi_Host *host = stor_device->host;
1677 
1678 	scsi_remove_host(host);
1679 	storvsc_dev_remove(dev);
1680 	scsi_host_put(host);
1681 
1682 	return 0;
1683 }
1684 
1685 static struct hv_driver storvsc_drv = {
1686 	.name = KBUILD_MODNAME,
1687 	.id_table = id_table,
1688 	.probe = storvsc_probe,
1689 	.remove = storvsc_remove,
1690 };
1691 
1692 static int __init storvsc_drv_init(void)
1693 {
1694 
1695 	/*
1696 	 * Divide the ring buffer data size (which is 1 page less
1697 	 * than the ring buffer size since that page is reserved for
1698 	 * the ring buffer indices) by the max request size (which is
1699 	 * vmbus_channel_packet_multipage_buffer + struct vstor_packet + u64)
1700 	 */
1701 	max_outstanding_req_per_channel =
1702 		((storvsc_ringbuffer_size - PAGE_SIZE) /
1703 		ALIGN(MAX_MULTIPAGE_BUFFER_PACKET +
1704 		sizeof(struct vstor_packet) + sizeof(u64) -
1705 		vmscsi_size_delta,
1706 		sizeof(u64)));
1707 
1708 	return vmbus_driver_register(&storvsc_drv);
1709 }
1710 
1711 static void __exit storvsc_drv_exit(void)
1712 {
1713 	vmbus_driver_unregister(&storvsc_drv);
1714 }
1715 
1716 MODULE_LICENSE("GPL");
1717 MODULE_DESCRIPTION("Microsoft Hyper-V virtual storage driver");
1718 module_init(storvsc_drv_init);
1719 module_exit(storvsc_drv_exit);
1720