xref: /linux/drivers/scsi/storvsc_drv.c (revision cbac924200b838cfb8d8b1415113d788089dc50b)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (c) 2009, Microsoft Corporation.
4  *
5  * Authors:
6  *   Haiyang Zhang <haiyangz@microsoft.com>
7  *   Hank Janssen  <hjanssen@microsoft.com>
8  *   K. Y. Srinivasan <kys@microsoft.com>
9  */
10 
11 #include <linux/kernel.h>
12 #include <linux/wait.h>
13 #include <linux/sched.h>
14 #include <linux/completion.h>
15 #include <linux/string.h>
16 #include <linux/mm.h>
17 #include <linux/delay.h>
18 #include <linux/init.h>
19 #include <linux/slab.h>
20 #include <linux/module.h>
21 #include <linux/device.h>
22 #include <linux/hyperv.h>
23 #include <linux/blkdev.h>
24 #include <linux/dma-mapping.h>
25 
26 #include <scsi/scsi.h>
27 #include <scsi/scsi_cmnd.h>
28 #include <scsi/scsi_host.h>
29 #include <scsi/scsi_device.h>
30 #include <scsi/scsi_tcq.h>
31 #include <scsi/scsi_eh.h>
32 #include <scsi/scsi_devinfo.h>
33 #include <scsi/scsi_dbg.h>
34 #include <scsi/scsi_transport_fc.h>
35 #include <scsi/scsi_transport.h>
36 
37 /*
38  * All wire protocol details (storage protocol between the guest and the host)
39  * are consolidated here.
40  *
41  * Begin protocol definitions.
42  */
43 
44 /*
45  * Version history:
46  * V1 Beta: 0.1
47  * V1 RC < 2008/1/31: 1.0
48  * V1 RC > 2008/1/31:  2.0
49  * Win7: 4.2
50  * Win8: 5.1
51  * Win8.1: 6.0
52  * Win10: 6.2
53  */
54 
55 #define VMSTOR_PROTO_VERSION(MAJOR_, MINOR_)	((((MAJOR_) & 0xff) << 8) | \
56 						(((MINOR_) & 0xff)))
57 
58 #define VMSTOR_PROTO_VERSION_WIN6	VMSTOR_PROTO_VERSION(2, 0)
59 #define VMSTOR_PROTO_VERSION_WIN7	VMSTOR_PROTO_VERSION(4, 2)
60 #define VMSTOR_PROTO_VERSION_WIN8	VMSTOR_PROTO_VERSION(5, 1)
61 #define VMSTOR_PROTO_VERSION_WIN8_1	VMSTOR_PROTO_VERSION(6, 0)
62 #define VMSTOR_PROTO_VERSION_WIN10	VMSTOR_PROTO_VERSION(6, 2)
63 
64 /*  Packet structure describing virtual storage requests. */
65 enum vstor_packet_operation {
66 	VSTOR_OPERATION_COMPLETE_IO		= 1,
67 	VSTOR_OPERATION_REMOVE_DEVICE		= 2,
68 	VSTOR_OPERATION_EXECUTE_SRB		= 3,
69 	VSTOR_OPERATION_RESET_LUN		= 4,
70 	VSTOR_OPERATION_RESET_ADAPTER		= 5,
71 	VSTOR_OPERATION_RESET_BUS		= 6,
72 	VSTOR_OPERATION_BEGIN_INITIALIZATION	= 7,
73 	VSTOR_OPERATION_END_INITIALIZATION	= 8,
74 	VSTOR_OPERATION_QUERY_PROTOCOL_VERSION	= 9,
75 	VSTOR_OPERATION_QUERY_PROPERTIES	= 10,
76 	VSTOR_OPERATION_ENUMERATE_BUS		= 11,
77 	VSTOR_OPERATION_FCHBA_DATA              = 12,
78 	VSTOR_OPERATION_CREATE_SUB_CHANNELS     = 13,
79 	VSTOR_OPERATION_MAXIMUM                 = 13
80 };
81 
82 /*
83  * WWN packet for Fibre Channel HBA
84  */
85 
86 struct hv_fc_wwn_packet {
87 	u8	primary_active;
88 	u8	reserved1[3];
89 	u8	primary_port_wwn[8];
90 	u8	primary_node_wwn[8];
91 	u8	secondary_port_wwn[8];
92 	u8	secondary_node_wwn[8];
93 };
94 
95 
96 
97 /*
98  * SRB Flag Bits
99  */
100 
101 #define SRB_FLAGS_QUEUE_ACTION_ENABLE		0x00000002
102 #define SRB_FLAGS_DISABLE_DISCONNECT		0x00000004
103 #define SRB_FLAGS_DISABLE_SYNCH_TRANSFER	0x00000008
104 #define SRB_FLAGS_BYPASS_FROZEN_QUEUE		0x00000010
105 #define SRB_FLAGS_DISABLE_AUTOSENSE		0x00000020
106 #define SRB_FLAGS_DATA_IN			0x00000040
107 #define SRB_FLAGS_DATA_OUT			0x00000080
108 #define SRB_FLAGS_NO_DATA_TRANSFER		0x00000000
109 #define SRB_FLAGS_UNSPECIFIED_DIRECTION	(SRB_FLAGS_DATA_IN | SRB_FLAGS_DATA_OUT)
110 #define SRB_FLAGS_NO_QUEUE_FREEZE		0x00000100
111 #define SRB_FLAGS_ADAPTER_CACHE_ENABLE		0x00000200
112 #define SRB_FLAGS_FREE_SENSE_BUFFER		0x00000400
113 
114 /*
115  * This flag indicates the request is part of the workflow for processing a D3.
116  */
117 #define SRB_FLAGS_D3_PROCESSING			0x00000800
118 #define SRB_FLAGS_IS_ACTIVE			0x00010000
119 #define SRB_FLAGS_ALLOCATED_FROM_ZONE		0x00020000
120 #define SRB_FLAGS_SGLIST_FROM_POOL		0x00040000
121 #define SRB_FLAGS_BYPASS_LOCKED_QUEUE		0x00080000
122 #define SRB_FLAGS_NO_KEEP_AWAKE			0x00100000
123 #define SRB_FLAGS_PORT_DRIVER_ALLOCSENSE	0x00200000
124 #define SRB_FLAGS_PORT_DRIVER_SENSEHASPORT	0x00400000
125 #define SRB_FLAGS_DONT_START_NEXT_PACKET	0x00800000
126 #define SRB_FLAGS_PORT_DRIVER_RESERVED		0x0F000000
127 #define SRB_FLAGS_CLASS_DRIVER_RESERVED		0xF0000000
128 
129 #define SP_UNTAGGED			((unsigned char) ~0)
130 #define SRB_SIMPLE_TAG_REQUEST		0x20
131 
132 /*
133  * Platform neutral description of a scsi request -
134  * this remains the same across the write regardless of 32/64 bit
135  * note: it's patterned off the SCSI_PASS_THROUGH structure
136  */
137 #define STORVSC_MAX_CMD_LEN			0x10
138 
139 #define POST_WIN7_STORVSC_SENSE_BUFFER_SIZE	0x14
140 #define PRE_WIN8_STORVSC_SENSE_BUFFER_SIZE	0x12
141 
142 #define STORVSC_SENSE_BUFFER_SIZE		0x14
143 #define STORVSC_MAX_BUF_LEN_WITH_PADDING	0x14
144 
145 /*
146  * Sense buffer size changed in win8; have a run-time
147  * variable to track the size we should use.  This value will
148  * likely change during protocol negotiation but it is valid
149  * to start by assuming pre-Win8.
150  */
151 static int sense_buffer_size = PRE_WIN8_STORVSC_SENSE_BUFFER_SIZE;
152 
153 /*
154  * The storage protocol version is determined during the
155  * initial exchange with the host.  It will indicate which
156  * storage functionality is available in the host.
157 */
158 static int vmstor_proto_version;
159 
160 #define STORVSC_LOGGING_NONE	0
161 #define STORVSC_LOGGING_ERROR	1
162 #define STORVSC_LOGGING_WARN	2
163 
164 static int logging_level = STORVSC_LOGGING_ERROR;
165 module_param(logging_level, int, S_IRUGO|S_IWUSR);
166 MODULE_PARM_DESC(logging_level,
167 	"Logging level, 0 - None, 1 - Error (default), 2 - Warning.");
168 
169 static inline bool do_logging(int level)
170 {
171 	return logging_level >= level;
172 }
173 
174 #define storvsc_log(dev, level, fmt, ...)			\
175 do {								\
176 	if (do_logging(level))					\
177 		dev_warn(&(dev)->device, fmt, ##__VA_ARGS__);	\
178 } while (0)
179 
180 struct vmscsi_win8_extension {
181 	/*
182 	 * The following were added in Windows 8
183 	 */
184 	u16 reserve;
185 	u8  queue_tag;
186 	u8  queue_action;
187 	u32 srb_flags;
188 	u32 time_out_value;
189 	u32 queue_sort_ey;
190 } __packed;
191 
192 struct vmscsi_request {
193 	u16 length;
194 	u8 srb_status;
195 	u8 scsi_status;
196 
197 	u8  port_number;
198 	u8  path_id;
199 	u8  target_id;
200 	u8  lun;
201 
202 	u8  cdb_length;
203 	u8  sense_info_length;
204 	u8  data_in;
205 	u8  reserved;
206 
207 	u32 data_transfer_length;
208 
209 	union {
210 		u8 cdb[STORVSC_MAX_CMD_LEN];
211 		u8 sense_data[STORVSC_SENSE_BUFFER_SIZE];
212 		u8 reserved_array[STORVSC_MAX_BUF_LEN_WITH_PADDING];
213 	};
214 	/*
215 	 * The following was added in win8.
216 	 */
217 	struct vmscsi_win8_extension win8_extension;
218 
219 } __attribute((packed));
220 
221 /*
222  * The list of storage protocols in order of preference.
223  */
224 struct vmstor_protocol {
225 	int protocol_version;
226 	int sense_buffer_size;
227 	int vmscsi_size_delta;
228 };
229 
230 
231 static const struct vmstor_protocol vmstor_protocols[] = {
232 	{
233 		VMSTOR_PROTO_VERSION_WIN10,
234 		POST_WIN7_STORVSC_SENSE_BUFFER_SIZE,
235 		0
236 	},
237 	{
238 		VMSTOR_PROTO_VERSION_WIN8_1,
239 		POST_WIN7_STORVSC_SENSE_BUFFER_SIZE,
240 		0
241 	},
242 	{
243 		VMSTOR_PROTO_VERSION_WIN8,
244 		POST_WIN7_STORVSC_SENSE_BUFFER_SIZE,
245 		0
246 	},
247 	{
248 		VMSTOR_PROTO_VERSION_WIN7,
249 		PRE_WIN8_STORVSC_SENSE_BUFFER_SIZE,
250 		sizeof(struct vmscsi_win8_extension),
251 	},
252 	{
253 		VMSTOR_PROTO_VERSION_WIN6,
254 		PRE_WIN8_STORVSC_SENSE_BUFFER_SIZE,
255 		sizeof(struct vmscsi_win8_extension),
256 	}
257 };
258 
259 
260 /*
261  * This structure is sent during the initialization phase to get the different
262  * properties of the channel.
263  */
264 
265 #define STORAGE_CHANNEL_SUPPORTS_MULTI_CHANNEL		0x1
266 
267 struct vmstorage_channel_properties {
268 	u32 reserved;
269 	u16 max_channel_cnt;
270 	u16 reserved1;
271 
272 	u32 flags;
273 	u32   max_transfer_bytes;
274 
275 	u64  reserved2;
276 } __packed;
277 
278 /*  This structure is sent during the storage protocol negotiations. */
279 struct vmstorage_protocol_version {
280 	/* Major (MSW) and minor (LSW) version numbers. */
281 	u16 major_minor;
282 
283 	/*
284 	 * Revision number is auto-incremented whenever this file is changed
285 	 * (See FILL_VMSTOR_REVISION macro above).  Mismatch does not
286 	 * definitely indicate incompatibility--but it does indicate mismatched
287 	 * builds.
288 	 * This is only used on the windows side. Just set it to 0.
289 	 */
290 	u16 revision;
291 } __packed;
292 
293 /* Channel Property Flags */
294 #define STORAGE_CHANNEL_REMOVABLE_FLAG		0x1
295 #define STORAGE_CHANNEL_EMULATED_IDE_FLAG	0x2
296 
297 struct vstor_packet {
298 	/* Requested operation type */
299 	enum vstor_packet_operation operation;
300 
301 	/*  Flags - see below for values */
302 	u32 flags;
303 
304 	/* Status of the request returned from the server side. */
305 	u32 status;
306 
307 	/* Data payload area */
308 	union {
309 		/*
310 		 * Structure used to forward SCSI commands from the
311 		 * client to the server.
312 		 */
313 		struct vmscsi_request vm_srb;
314 
315 		/* Structure used to query channel properties. */
316 		struct vmstorage_channel_properties storage_channel_properties;
317 
318 		/* Used during version negotiations. */
319 		struct vmstorage_protocol_version version;
320 
321 		/* Fibre channel address packet */
322 		struct hv_fc_wwn_packet wwn_packet;
323 
324 		/* Number of sub-channels to create */
325 		u16 sub_channel_count;
326 
327 		/* This will be the maximum of the union members */
328 		u8  buffer[0x34];
329 	};
330 } __packed;
331 
332 /*
333  * Packet Flags:
334  *
335  * This flag indicates that the server should send back a completion for this
336  * packet.
337  */
338 
339 #define REQUEST_COMPLETION_FLAG	0x1
340 
341 /* Matches Windows-end */
342 enum storvsc_request_type {
343 	WRITE_TYPE = 0,
344 	READ_TYPE,
345 	UNKNOWN_TYPE,
346 };
347 
348 /*
349  * SRB status codes and masks; a subset of the codes used here.
350  */
351 
352 #define SRB_STATUS_AUTOSENSE_VALID	0x80
353 #define SRB_STATUS_QUEUE_FROZEN		0x40
354 #define SRB_STATUS_INVALID_LUN	0x20
355 #define SRB_STATUS_SUCCESS	0x01
356 #define SRB_STATUS_ABORTED	0x02
357 #define SRB_STATUS_ERROR	0x04
358 #define SRB_STATUS_DATA_OVERRUN	0x12
359 
360 #define SRB_STATUS(status) \
361 	(status & ~(SRB_STATUS_AUTOSENSE_VALID | SRB_STATUS_QUEUE_FROZEN))
362 /*
363  * This is the end of Protocol specific defines.
364  */
365 
366 static int storvsc_ringbuffer_size = (128 * 1024);
367 static u32 max_outstanding_req_per_channel;
368 static int storvsc_change_queue_depth(struct scsi_device *sdev, int queue_depth);
369 
370 static int storvsc_vcpus_per_sub_channel = 4;
371 static unsigned int storvsc_max_hw_queues;
372 
373 module_param(storvsc_ringbuffer_size, int, S_IRUGO);
374 MODULE_PARM_DESC(storvsc_ringbuffer_size, "Ring buffer size (bytes)");
375 
376 module_param(storvsc_max_hw_queues, uint, 0644);
377 MODULE_PARM_DESC(storvsc_max_hw_queues, "Maximum number of hardware queues");
378 
379 module_param(storvsc_vcpus_per_sub_channel, int, S_IRUGO);
380 MODULE_PARM_DESC(storvsc_vcpus_per_sub_channel, "Ratio of VCPUs to subchannels");
381 
382 static int ring_avail_percent_lowater = 10;
383 module_param(ring_avail_percent_lowater, int, S_IRUGO);
384 MODULE_PARM_DESC(ring_avail_percent_lowater,
385 		"Select a channel if available ring size > this in percent");
386 
387 /*
388  * Timeout in seconds for all devices managed by this driver.
389  */
390 static int storvsc_timeout = 180;
391 
392 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
393 static struct scsi_transport_template *fc_transport_template;
394 #endif
395 
396 static struct scsi_host_template scsi_driver;
397 static void storvsc_on_channel_callback(void *context);
398 
399 #define STORVSC_MAX_LUNS_PER_TARGET			255
400 #define STORVSC_MAX_TARGETS				2
401 #define STORVSC_MAX_CHANNELS				8
402 
403 #define STORVSC_FC_MAX_LUNS_PER_TARGET			255
404 #define STORVSC_FC_MAX_TARGETS				128
405 #define STORVSC_FC_MAX_CHANNELS				8
406 
407 #define STORVSC_IDE_MAX_LUNS_PER_TARGET			64
408 #define STORVSC_IDE_MAX_TARGETS				1
409 #define STORVSC_IDE_MAX_CHANNELS			1
410 
411 /*
412  * Upper bound on the size of a storvsc packet. vmscsi_size_delta is not
413  * included in the calculation because it is set after STORVSC_MAX_PKT_SIZE
414  * is used in storvsc_connect_to_vsp
415  */
416 #define STORVSC_MAX_PKT_SIZE (sizeof(struct vmpacket_descriptor) +\
417 			      sizeof(struct vstor_packet))
418 
419 struct storvsc_cmd_request {
420 	struct scsi_cmnd *cmd;
421 
422 	struct hv_device *device;
423 
424 	/* Synchronize the request/response if needed */
425 	struct completion wait_event;
426 
427 	struct vmbus_channel_packet_multipage_buffer mpb;
428 	struct vmbus_packet_mpb_array *payload;
429 	u32 payload_sz;
430 
431 	struct vstor_packet vstor_packet;
432 };
433 
434 
435 /* A storvsc device is a device object that contains a vmbus channel */
436 struct storvsc_device {
437 	struct hv_device *device;
438 
439 	bool	 destroy;
440 	bool	 drain_notify;
441 	atomic_t num_outstanding_req;
442 	struct Scsi_Host *host;
443 
444 	wait_queue_head_t waiting_to_drain;
445 
446 	/*
447 	 * Each unique Port/Path/Target represents 1 channel ie scsi
448 	 * controller. In reality, the pathid, targetid is always 0
449 	 * and the port is set by us
450 	 */
451 	unsigned int port_number;
452 	unsigned char path_id;
453 	unsigned char target_id;
454 
455 	/*
456 	 * The size of the vmscsi_request has changed in win8. The
457 	 * additional size is because of new elements added to the
458 	 * structure. These elements are valid only when we are talking
459 	 * to a win8 host.
460 	 * Track the correction to size we need to apply. This value
461 	 * will likely change during protocol negotiation but it is
462 	 * valid to start by assuming pre-Win8.
463 	 */
464 	int vmscsi_size_delta;
465 
466 	/*
467 	 * Max I/O, the device can support.
468 	 */
469 	u32   max_transfer_bytes;
470 	/*
471 	 * Number of sub-channels we will open.
472 	 */
473 	u16 num_sc;
474 	struct vmbus_channel **stor_chns;
475 	/*
476 	 * Mask of CPUs bound to subchannels.
477 	 */
478 	struct cpumask alloced_cpus;
479 	/*
480 	 * Serializes modifications of stor_chns[] from storvsc_do_io()
481 	 * and storvsc_change_target_cpu().
482 	 */
483 	spinlock_t lock;
484 	/* Used for vsc/vsp channel reset process */
485 	struct storvsc_cmd_request init_request;
486 	struct storvsc_cmd_request reset_request;
487 	/*
488 	 * Currently active port and node names for FC devices.
489 	 */
490 	u64 node_name;
491 	u64 port_name;
492 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
493 	struct fc_rport *rport;
494 #endif
495 };
496 
497 struct hv_host_device {
498 	struct hv_device *dev;
499 	unsigned int port;
500 	unsigned char path;
501 	unsigned char target;
502 	struct workqueue_struct *handle_error_wq;
503 	struct work_struct host_scan_work;
504 	struct Scsi_Host *host;
505 };
506 
507 struct storvsc_scan_work {
508 	struct work_struct work;
509 	struct Scsi_Host *host;
510 	u8 lun;
511 	u8 tgt_id;
512 };
513 
514 static void storvsc_device_scan(struct work_struct *work)
515 {
516 	struct storvsc_scan_work *wrk;
517 	struct scsi_device *sdev;
518 
519 	wrk = container_of(work, struct storvsc_scan_work, work);
520 
521 	sdev = scsi_device_lookup(wrk->host, 0, wrk->tgt_id, wrk->lun);
522 	if (!sdev)
523 		goto done;
524 	scsi_rescan_device(&sdev->sdev_gendev);
525 	scsi_device_put(sdev);
526 
527 done:
528 	kfree(wrk);
529 }
530 
531 static void storvsc_host_scan(struct work_struct *work)
532 {
533 	struct Scsi_Host *host;
534 	struct scsi_device *sdev;
535 	struct hv_host_device *host_device =
536 		container_of(work, struct hv_host_device, host_scan_work);
537 
538 	host = host_device->host;
539 	/*
540 	 * Before scanning the host, first check to see if any of the
541 	 * currrently known devices have been hot removed. We issue a
542 	 * "unit ready" command against all currently known devices.
543 	 * This I/O will result in an error for devices that have been
544 	 * removed. As part of handling the I/O error, we remove the device.
545 	 *
546 	 * When a LUN is added or removed, the host sends us a signal to
547 	 * scan the host. Thus we are forced to discover the LUNs that
548 	 * may have been removed this way.
549 	 */
550 	mutex_lock(&host->scan_mutex);
551 	shost_for_each_device(sdev, host)
552 		scsi_test_unit_ready(sdev, 1, 1, NULL);
553 	mutex_unlock(&host->scan_mutex);
554 	/*
555 	 * Now scan the host to discover LUNs that may have been added.
556 	 */
557 	scsi_scan_host(host);
558 }
559 
560 static void storvsc_remove_lun(struct work_struct *work)
561 {
562 	struct storvsc_scan_work *wrk;
563 	struct scsi_device *sdev;
564 
565 	wrk = container_of(work, struct storvsc_scan_work, work);
566 	if (!scsi_host_get(wrk->host))
567 		goto done;
568 
569 	sdev = scsi_device_lookup(wrk->host, 0, wrk->tgt_id, wrk->lun);
570 
571 	if (sdev) {
572 		scsi_remove_device(sdev);
573 		scsi_device_put(sdev);
574 	}
575 	scsi_host_put(wrk->host);
576 
577 done:
578 	kfree(wrk);
579 }
580 
581 
582 /*
583  * We can get incoming messages from the host that are not in response to
584  * messages that we have sent out. An example of this would be messages
585  * received by the guest to notify dynamic addition/removal of LUNs. To
586  * deal with potential race conditions where the driver may be in the
587  * midst of being unloaded when we might receive an unsolicited message
588  * from the host, we have implemented a mechanism to gurantee sequential
589  * consistency:
590  *
591  * 1) Once the device is marked as being destroyed, we will fail all
592  *    outgoing messages.
593  * 2) We permit incoming messages when the device is being destroyed,
594  *    only to properly account for messages already sent out.
595  */
596 
597 static inline struct storvsc_device *get_out_stor_device(
598 					struct hv_device *device)
599 {
600 	struct storvsc_device *stor_device;
601 
602 	stor_device = hv_get_drvdata(device);
603 
604 	if (stor_device && stor_device->destroy)
605 		stor_device = NULL;
606 
607 	return stor_device;
608 }
609 
610 
611 static inline void storvsc_wait_to_drain(struct storvsc_device *dev)
612 {
613 	dev->drain_notify = true;
614 	wait_event(dev->waiting_to_drain,
615 		   atomic_read(&dev->num_outstanding_req) == 0);
616 	dev->drain_notify = false;
617 }
618 
619 static inline struct storvsc_device *get_in_stor_device(
620 					struct hv_device *device)
621 {
622 	struct storvsc_device *stor_device;
623 
624 	stor_device = hv_get_drvdata(device);
625 
626 	if (!stor_device)
627 		goto get_in_err;
628 
629 	/*
630 	 * If the device is being destroyed; allow incoming
631 	 * traffic only to cleanup outstanding requests.
632 	 */
633 
634 	if (stor_device->destroy  &&
635 		(atomic_read(&stor_device->num_outstanding_req) == 0))
636 		stor_device = NULL;
637 
638 get_in_err:
639 	return stor_device;
640 
641 }
642 
643 static void storvsc_change_target_cpu(struct vmbus_channel *channel, u32 old,
644 				      u32 new)
645 {
646 	struct storvsc_device *stor_device;
647 	struct vmbus_channel *cur_chn;
648 	bool old_is_alloced = false;
649 	struct hv_device *device;
650 	unsigned long flags;
651 	int cpu;
652 
653 	device = channel->primary_channel ?
654 			channel->primary_channel->device_obj
655 				: channel->device_obj;
656 	stor_device = get_out_stor_device(device);
657 	if (!stor_device)
658 		return;
659 
660 	/* See storvsc_do_io() -> get_og_chn(). */
661 	spin_lock_irqsave(&stor_device->lock, flags);
662 
663 	/*
664 	 * Determines if the storvsc device has other channels assigned to
665 	 * the "old" CPU to update the alloced_cpus mask and the stor_chns
666 	 * array.
667 	 */
668 	if (device->channel != channel && device->channel->target_cpu == old) {
669 		cur_chn = device->channel;
670 		old_is_alloced = true;
671 		goto old_is_alloced;
672 	}
673 	list_for_each_entry(cur_chn, &device->channel->sc_list, sc_list) {
674 		if (cur_chn == channel)
675 			continue;
676 		if (cur_chn->target_cpu == old) {
677 			old_is_alloced = true;
678 			goto old_is_alloced;
679 		}
680 	}
681 
682 old_is_alloced:
683 	if (old_is_alloced)
684 		WRITE_ONCE(stor_device->stor_chns[old], cur_chn);
685 	else
686 		cpumask_clear_cpu(old, &stor_device->alloced_cpus);
687 
688 	/* "Flush" the stor_chns array. */
689 	for_each_possible_cpu(cpu) {
690 		if (stor_device->stor_chns[cpu] && !cpumask_test_cpu(
691 					cpu, &stor_device->alloced_cpus))
692 			WRITE_ONCE(stor_device->stor_chns[cpu], NULL);
693 	}
694 
695 	WRITE_ONCE(stor_device->stor_chns[new], channel);
696 	cpumask_set_cpu(new, &stor_device->alloced_cpus);
697 
698 	spin_unlock_irqrestore(&stor_device->lock, flags);
699 }
700 
701 static u64 storvsc_next_request_id(struct vmbus_channel *channel, u64 rqst_addr)
702 {
703 	struct storvsc_cmd_request *request =
704 		(struct storvsc_cmd_request *)(unsigned long)rqst_addr;
705 
706 	if (rqst_addr == VMBUS_RQST_INIT)
707 		return VMBUS_RQST_INIT;
708 	if (rqst_addr == VMBUS_RQST_RESET)
709 		return VMBUS_RQST_RESET;
710 
711 	/*
712 	 * Cannot return an ID of 0, which is reserved for an unsolicited
713 	 * message from Hyper-V.
714 	 */
715 	return (u64)blk_mq_unique_tag(scsi_cmd_to_rq(request->cmd)) + 1;
716 }
717 
718 static void handle_sc_creation(struct vmbus_channel *new_sc)
719 {
720 	struct hv_device *device = new_sc->primary_channel->device_obj;
721 	struct device *dev = &device->device;
722 	struct storvsc_device *stor_device;
723 	struct vmstorage_channel_properties props;
724 	int ret;
725 
726 	stor_device = get_out_stor_device(device);
727 	if (!stor_device)
728 		return;
729 
730 	memset(&props, 0, sizeof(struct vmstorage_channel_properties));
731 	new_sc->max_pkt_size = STORVSC_MAX_PKT_SIZE;
732 
733 	new_sc->next_request_id_callback = storvsc_next_request_id;
734 
735 	ret = vmbus_open(new_sc,
736 			 storvsc_ringbuffer_size,
737 			 storvsc_ringbuffer_size,
738 			 (void *)&props,
739 			 sizeof(struct vmstorage_channel_properties),
740 			 storvsc_on_channel_callback, new_sc);
741 
742 	/* In case vmbus_open() fails, we don't use the sub-channel. */
743 	if (ret != 0) {
744 		dev_err(dev, "Failed to open sub-channel: err=%d\n", ret);
745 		return;
746 	}
747 
748 	new_sc->change_target_cpu_callback = storvsc_change_target_cpu;
749 
750 	/* Add the sub-channel to the array of available channels. */
751 	stor_device->stor_chns[new_sc->target_cpu] = new_sc;
752 	cpumask_set_cpu(new_sc->target_cpu, &stor_device->alloced_cpus);
753 }
754 
755 static void  handle_multichannel_storage(struct hv_device *device, int max_chns)
756 {
757 	struct device *dev = &device->device;
758 	struct storvsc_device *stor_device;
759 	int num_sc;
760 	struct storvsc_cmd_request *request;
761 	struct vstor_packet *vstor_packet;
762 	int ret, t;
763 
764 	/*
765 	 * If the number of CPUs is artificially restricted, such as
766 	 * with maxcpus=1 on the kernel boot line, Hyper-V could offer
767 	 * sub-channels >= the number of CPUs. These sub-channels
768 	 * should not be created. The primary channel is already created
769 	 * and assigned to one CPU, so check against # CPUs - 1.
770 	 */
771 	num_sc = min((int)(num_online_cpus() - 1), max_chns);
772 	if (!num_sc)
773 		return;
774 
775 	stor_device = get_out_stor_device(device);
776 	if (!stor_device)
777 		return;
778 
779 	stor_device->num_sc = num_sc;
780 	request = &stor_device->init_request;
781 	vstor_packet = &request->vstor_packet;
782 
783 	/*
784 	 * Establish a handler for dealing with subchannels.
785 	 */
786 	vmbus_set_sc_create_callback(device->channel, handle_sc_creation);
787 
788 	/*
789 	 * Request the host to create sub-channels.
790 	 */
791 	memset(request, 0, sizeof(struct storvsc_cmd_request));
792 	init_completion(&request->wait_event);
793 	vstor_packet->operation = VSTOR_OPERATION_CREATE_SUB_CHANNELS;
794 	vstor_packet->flags = REQUEST_COMPLETION_FLAG;
795 	vstor_packet->sub_channel_count = num_sc;
796 
797 	ret = vmbus_sendpacket(device->channel, vstor_packet,
798 			       (sizeof(struct vstor_packet) -
799 			       stor_device->vmscsi_size_delta),
800 			       VMBUS_RQST_INIT,
801 			       VM_PKT_DATA_INBAND,
802 			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
803 
804 	if (ret != 0) {
805 		dev_err(dev, "Failed to create sub-channel: err=%d\n", ret);
806 		return;
807 	}
808 
809 	t = wait_for_completion_timeout(&request->wait_event, 10*HZ);
810 	if (t == 0) {
811 		dev_err(dev, "Failed to create sub-channel: timed out\n");
812 		return;
813 	}
814 
815 	if (vstor_packet->operation != VSTOR_OPERATION_COMPLETE_IO ||
816 	    vstor_packet->status != 0) {
817 		dev_err(dev, "Failed to create sub-channel: op=%d, sts=%d\n",
818 			vstor_packet->operation, vstor_packet->status);
819 		return;
820 	}
821 
822 	/*
823 	 * We need to do nothing here, because vmbus_process_offer()
824 	 * invokes channel->sc_creation_callback, which will open and use
825 	 * the sub-channel(s).
826 	 */
827 }
828 
829 static void cache_wwn(struct storvsc_device *stor_device,
830 		      struct vstor_packet *vstor_packet)
831 {
832 	/*
833 	 * Cache the currently active port and node ww names.
834 	 */
835 	if (vstor_packet->wwn_packet.primary_active) {
836 		stor_device->node_name =
837 			wwn_to_u64(vstor_packet->wwn_packet.primary_node_wwn);
838 		stor_device->port_name =
839 			wwn_to_u64(vstor_packet->wwn_packet.primary_port_wwn);
840 	} else {
841 		stor_device->node_name =
842 			wwn_to_u64(vstor_packet->wwn_packet.secondary_node_wwn);
843 		stor_device->port_name =
844 			wwn_to_u64(vstor_packet->wwn_packet.secondary_port_wwn);
845 	}
846 }
847 
848 
849 static int storvsc_execute_vstor_op(struct hv_device *device,
850 				    struct storvsc_cmd_request *request,
851 				    bool status_check)
852 {
853 	struct storvsc_device *stor_device;
854 	struct vstor_packet *vstor_packet;
855 	int ret, t;
856 
857 	stor_device = get_out_stor_device(device);
858 	if (!stor_device)
859 		return -ENODEV;
860 
861 	vstor_packet = &request->vstor_packet;
862 
863 	init_completion(&request->wait_event);
864 	vstor_packet->flags = REQUEST_COMPLETION_FLAG;
865 
866 	ret = vmbus_sendpacket(device->channel, vstor_packet,
867 			       (sizeof(struct vstor_packet) -
868 			       stor_device->vmscsi_size_delta),
869 			       VMBUS_RQST_INIT,
870 			       VM_PKT_DATA_INBAND,
871 			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
872 	if (ret != 0)
873 		return ret;
874 
875 	t = wait_for_completion_timeout(&request->wait_event, 5*HZ);
876 	if (t == 0)
877 		return -ETIMEDOUT;
878 
879 	if (!status_check)
880 		return ret;
881 
882 	if (vstor_packet->operation != VSTOR_OPERATION_COMPLETE_IO ||
883 	    vstor_packet->status != 0)
884 		return -EINVAL;
885 
886 	return ret;
887 }
888 
889 static int storvsc_channel_init(struct hv_device *device, bool is_fc)
890 {
891 	struct storvsc_device *stor_device;
892 	struct storvsc_cmd_request *request;
893 	struct vstor_packet *vstor_packet;
894 	int ret, i;
895 	int max_chns;
896 	bool process_sub_channels = false;
897 
898 	stor_device = get_out_stor_device(device);
899 	if (!stor_device)
900 		return -ENODEV;
901 
902 	request = &stor_device->init_request;
903 	vstor_packet = &request->vstor_packet;
904 
905 	/*
906 	 * Now, initiate the vsc/vsp initialization protocol on the open
907 	 * channel
908 	 */
909 	memset(request, 0, sizeof(struct storvsc_cmd_request));
910 	vstor_packet->operation = VSTOR_OPERATION_BEGIN_INITIALIZATION;
911 	ret = storvsc_execute_vstor_op(device, request, true);
912 	if (ret)
913 		return ret;
914 	/*
915 	 * Query host supported protocol version.
916 	 */
917 
918 	for (i = 0; i < ARRAY_SIZE(vmstor_protocols); i++) {
919 		/* reuse the packet for version range supported */
920 		memset(vstor_packet, 0, sizeof(struct vstor_packet));
921 		vstor_packet->operation =
922 			VSTOR_OPERATION_QUERY_PROTOCOL_VERSION;
923 
924 		vstor_packet->version.major_minor =
925 			vmstor_protocols[i].protocol_version;
926 
927 		/*
928 		 * The revision number is only used in Windows; set it to 0.
929 		 */
930 		vstor_packet->version.revision = 0;
931 		ret = storvsc_execute_vstor_op(device, request, false);
932 		if (ret != 0)
933 			return ret;
934 
935 		if (vstor_packet->operation != VSTOR_OPERATION_COMPLETE_IO)
936 			return -EINVAL;
937 
938 		if (vstor_packet->status == 0) {
939 			vmstor_proto_version =
940 				vmstor_protocols[i].protocol_version;
941 
942 			sense_buffer_size =
943 				vmstor_protocols[i].sense_buffer_size;
944 
945 			stor_device->vmscsi_size_delta =
946 				vmstor_protocols[i].vmscsi_size_delta;
947 
948 			break;
949 		}
950 	}
951 
952 	if (vstor_packet->status != 0)
953 		return -EINVAL;
954 
955 
956 	memset(vstor_packet, 0, sizeof(struct vstor_packet));
957 	vstor_packet->operation = VSTOR_OPERATION_QUERY_PROPERTIES;
958 	ret = storvsc_execute_vstor_op(device, request, true);
959 	if (ret != 0)
960 		return ret;
961 
962 	/*
963 	 * Check to see if multi-channel support is there.
964 	 * Hosts that implement protocol version of 5.1 and above
965 	 * support multi-channel.
966 	 */
967 	max_chns = vstor_packet->storage_channel_properties.max_channel_cnt;
968 
969 	/*
970 	 * Allocate state to manage the sub-channels.
971 	 * We allocate an array based on the numbers of possible CPUs
972 	 * (Hyper-V does not support cpu online/offline).
973 	 * This Array will be sparseley populated with unique
974 	 * channels - primary + sub-channels.
975 	 * We will however populate all the slots to evenly distribute
976 	 * the load.
977 	 */
978 	stor_device->stor_chns = kcalloc(num_possible_cpus(), sizeof(void *),
979 					 GFP_KERNEL);
980 	if (stor_device->stor_chns == NULL)
981 		return -ENOMEM;
982 
983 	device->channel->change_target_cpu_callback = storvsc_change_target_cpu;
984 
985 	stor_device->stor_chns[device->channel->target_cpu] = device->channel;
986 	cpumask_set_cpu(device->channel->target_cpu,
987 			&stor_device->alloced_cpus);
988 
989 	if (vmstor_proto_version >= VMSTOR_PROTO_VERSION_WIN8) {
990 		if (vstor_packet->storage_channel_properties.flags &
991 		    STORAGE_CHANNEL_SUPPORTS_MULTI_CHANNEL)
992 			process_sub_channels = true;
993 	}
994 	stor_device->max_transfer_bytes =
995 		vstor_packet->storage_channel_properties.max_transfer_bytes;
996 
997 	if (!is_fc)
998 		goto done;
999 
1000 	/*
1001 	 * For FC devices retrieve FC HBA data.
1002 	 */
1003 	memset(vstor_packet, 0, sizeof(struct vstor_packet));
1004 	vstor_packet->operation = VSTOR_OPERATION_FCHBA_DATA;
1005 	ret = storvsc_execute_vstor_op(device, request, true);
1006 	if (ret != 0)
1007 		return ret;
1008 
1009 	/*
1010 	 * Cache the currently active port and node ww names.
1011 	 */
1012 	cache_wwn(stor_device, vstor_packet);
1013 
1014 done:
1015 
1016 	memset(vstor_packet, 0, sizeof(struct vstor_packet));
1017 	vstor_packet->operation = VSTOR_OPERATION_END_INITIALIZATION;
1018 	ret = storvsc_execute_vstor_op(device, request, true);
1019 	if (ret != 0)
1020 		return ret;
1021 
1022 	if (process_sub_channels)
1023 		handle_multichannel_storage(device, max_chns);
1024 
1025 	return ret;
1026 }
1027 
1028 static void storvsc_handle_error(struct vmscsi_request *vm_srb,
1029 				struct scsi_cmnd *scmnd,
1030 				struct Scsi_Host *host,
1031 				u8 asc, u8 ascq)
1032 {
1033 	struct storvsc_scan_work *wrk;
1034 	void (*process_err_fn)(struct work_struct *work);
1035 	struct hv_host_device *host_dev = shost_priv(host);
1036 
1037 	/*
1038 	 * In some situations, Hyper-V sets multiple bits in the
1039 	 * srb_status, such as ABORTED and ERROR. So process them
1040 	 * individually, with the most specific bits first.
1041 	 */
1042 
1043 	if (vm_srb->srb_status & SRB_STATUS_INVALID_LUN) {
1044 		set_host_byte(scmnd, DID_NO_CONNECT);
1045 		process_err_fn = storvsc_remove_lun;
1046 		goto do_work;
1047 	}
1048 
1049 	if (vm_srb->srb_status & SRB_STATUS_ABORTED) {
1050 		if (vm_srb->srb_status & SRB_STATUS_AUTOSENSE_VALID &&
1051 		    /* Capacity data has changed */
1052 		    (asc == 0x2a) && (ascq == 0x9)) {
1053 			process_err_fn = storvsc_device_scan;
1054 			/*
1055 			 * Retry the I/O that triggered this.
1056 			 */
1057 			set_host_byte(scmnd, DID_REQUEUE);
1058 			goto do_work;
1059 		}
1060 	}
1061 
1062 	if (vm_srb->srb_status & SRB_STATUS_ERROR) {
1063 		/*
1064 		 * Let upper layer deal with error when
1065 		 * sense message is present.
1066 		 */
1067 		if (vm_srb->srb_status & SRB_STATUS_AUTOSENSE_VALID)
1068 			return;
1069 
1070 		/*
1071 		 * If there is an error; offline the device since all
1072 		 * error recovery strategies would have already been
1073 		 * deployed on the host side. However, if the command
1074 		 * were a pass-through command deal with it appropriately.
1075 		 */
1076 		switch (scmnd->cmnd[0]) {
1077 		case ATA_16:
1078 		case ATA_12:
1079 			set_host_byte(scmnd, DID_PASSTHROUGH);
1080 			break;
1081 		/*
1082 		 * On some Hyper-V hosts TEST_UNIT_READY command can
1083 		 * return SRB_STATUS_ERROR. Let the upper level code
1084 		 * deal with it based on the sense information.
1085 		 */
1086 		case TEST_UNIT_READY:
1087 			break;
1088 		default:
1089 			set_host_byte(scmnd, DID_ERROR);
1090 		}
1091 	}
1092 	return;
1093 
1094 do_work:
1095 	/*
1096 	 * We need to schedule work to process this error; schedule it.
1097 	 */
1098 	wrk = kmalloc(sizeof(struct storvsc_scan_work), GFP_ATOMIC);
1099 	if (!wrk) {
1100 		set_host_byte(scmnd, DID_TARGET_FAILURE);
1101 		return;
1102 	}
1103 
1104 	wrk->host = host;
1105 	wrk->lun = vm_srb->lun;
1106 	wrk->tgt_id = vm_srb->target_id;
1107 	INIT_WORK(&wrk->work, process_err_fn);
1108 	queue_work(host_dev->handle_error_wq, &wrk->work);
1109 }
1110 
1111 
1112 static void storvsc_command_completion(struct storvsc_cmd_request *cmd_request,
1113 				       struct storvsc_device *stor_dev)
1114 {
1115 	struct scsi_cmnd *scmnd = cmd_request->cmd;
1116 	struct scsi_sense_hdr sense_hdr;
1117 	struct vmscsi_request *vm_srb;
1118 	u32 data_transfer_length;
1119 	struct Scsi_Host *host;
1120 	u32 payload_sz = cmd_request->payload_sz;
1121 	void *payload = cmd_request->payload;
1122 	bool sense_ok;
1123 
1124 	host = stor_dev->host;
1125 
1126 	vm_srb = &cmd_request->vstor_packet.vm_srb;
1127 	data_transfer_length = vm_srb->data_transfer_length;
1128 
1129 	scmnd->result = vm_srb->scsi_status;
1130 
1131 	if (scmnd->result) {
1132 		sense_ok = scsi_normalize_sense(scmnd->sense_buffer,
1133 				SCSI_SENSE_BUFFERSIZE, &sense_hdr);
1134 
1135 		if (sense_ok && do_logging(STORVSC_LOGGING_WARN))
1136 			scsi_print_sense_hdr(scmnd->device, "storvsc",
1137 					     &sense_hdr);
1138 	}
1139 
1140 	if (vm_srb->srb_status != SRB_STATUS_SUCCESS) {
1141 		storvsc_handle_error(vm_srb, scmnd, host, sense_hdr.asc,
1142 					 sense_hdr.ascq);
1143 		/*
1144 		 * The Windows driver set data_transfer_length on
1145 		 * SRB_STATUS_DATA_OVERRUN. On other errors, this value
1146 		 * is untouched.  In these cases we set it to 0.
1147 		 */
1148 		if (vm_srb->srb_status != SRB_STATUS_DATA_OVERRUN)
1149 			data_transfer_length = 0;
1150 	}
1151 
1152 	/* Validate data_transfer_length (from Hyper-V) */
1153 	if (data_transfer_length > cmd_request->payload->range.len)
1154 		data_transfer_length = cmd_request->payload->range.len;
1155 
1156 	scsi_set_resid(scmnd,
1157 		cmd_request->payload->range.len - data_transfer_length);
1158 
1159 	scsi_done(scmnd);
1160 
1161 	if (payload_sz >
1162 		sizeof(struct vmbus_channel_packet_multipage_buffer))
1163 		kfree(payload);
1164 }
1165 
1166 static void storvsc_on_io_completion(struct storvsc_device *stor_device,
1167 				  struct vstor_packet *vstor_packet,
1168 				  struct storvsc_cmd_request *request)
1169 {
1170 	struct vstor_packet *stor_pkt;
1171 	struct hv_device *device = stor_device->device;
1172 
1173 	stor_pkt = &request->vstor_packet;
1174 
1175 	/*
1176 	 * The current SCSI handling on the host side does
1177 	 * not correctly handle:
1178 	 * INQUIRY command with page code parameter set to 0x80
1179 	 * MODE_SENSE command with cmd[2] == 0x1c
1180 	 *
1181 	 * Setup srb and scsi status so this won't be fatal.
1182 	 * We do this so we can distinguish truly fatal failues
1183 	 * (srb status == 0x4) and off-line the device in that case.
1184 	 */
1185 
1186 	if ((stor_pkt->vm_srb.cdb[0] == INQUIRY) ||
1187 	   (stor_pkt->vm_srb.cdb[0] == MODE_SENSE)) {
1188 		vstor_packet->vm_srb.scsi_status = 0;
1189 		vstor_packet->vm_srb.srb_status = SRB_STATUS_SUCCESS;
1190 	}
1191 
1192 	/* Copy over the status...etc */
1193 	stor_pkt->vm_srb.scsi_status = vstor_packet->vm_srb.scsi_status;
1194 	stor_pkt->vm_srb.srb_status = vstor_packet->vm_srb.srb_status;
1195 
1196 	/*
1197 	 * Copy over the sense_info_length, but limit to the known max
1198 	 * size if Hyper-V returns a bad value.
1199 	 */
1200 	stor_pkt->vm_srb.sense_info_length = min_t(u8, sense_buffer_size,
1201 		vstor_packet->vm_srb.sense_info_length);
1202 
1203 	if (vstor_packet->vm_srb.scsi_status != 0 ||
1204 	    vstor_packet->vm_srb.srb_status != SRB_STATUS_SUCCESS) {
1205 
1206 		/*
1207 		 * Log TEST_UNIT_READY errors only as warnings. Hyper-V can
1208 		 * return errors when detecting devices using TEST_UNIT_READY,
1209 		 * and logging these as errors produces unhelpful noise.
1210 		 */
1211 		int loglevel = (stor_pkt->vm_srb.cdb[0] == TEST_UNIT_READY) ?
1212 			STORVSC_LOGGING_WARN : STORVSC_LOGGING_ERROR;
1213 
1214 		storvsc_log(device, loglevel,
1215 			"tag#%d cmd 0x%x status: scsi 0x%x srb 0x%x hv 0x%x\n",
1216 			scsi_cmd_to_rq(request->cmd)->tag,
1217 			stor_pkt->vm_srb.cdb[0],
1218 			vstor_packet->vm_srb.scsi_status,
1219 			vstor_packet->vm_srb.srb_status,
1220 			vstor_packet->status);
1221 	}
1222 
1223 	if (vstor_packet->vm_srb.scsi_status == SAM_STAT_CHECK_CONDITION &&
1224 	    (vstor_packet->vm_srb.srb_status & SRB_STATUS_AUTOSENSE_VALID))
1225 		memcpy(request->cmd->sense_buffer,
1226 		       vstor_packet->vm_srb.sense_data,
1227 		       stor_pkt->vm_srb.sense_info_length);
1228 
1229 	stor_pkt->vm_srb.data_transfer_length =
1230 		vstor_packet->vm_srb.data_transfer_length;
1231 
1232 	storvsc_command_completion(request, stor_device);
1233 
1234 	if (atomic_dec_and_test(&stor_device->num_outstanding_req) &&
1235 		stor_device->drain_notify)
1236 		wake_up(&stor_device->waiting_to_drain);
1237 }
1238 
1239 static void storvsc_on_receive(struct storvsc_device *stor_device,
1240 			     struct vstor_packet *vstor_packet,
1241 			     struct storvsc_cmd_request *request)
1242 {
1243 	struct hv_host_device *host_dev;
1244 	switch (vstor_packet->operation) {
1245 	case VSTOR_OPERATION_COMPLETE_IO:
1246 		storvsc_on_io_completion(stor_device, vstor_packet, request);
1247 		break;
1248 
1249 	case VSTOR_OPERATION_REMOVE_DEVICE:
1250 	case VSTOR_OPERATION_ENUMERATE_BUS:
1251 		host_dev = shost_priv(stor_device->host);
1252 		queue_work(
1253 			host_dev->handle_error_wq, &host_dev->host_scan_work);
1254 		break;
1255 
1256 	case VSTOR_OPERATION_FCHBA_DATA:
1257 		cache_wwn(stor_device, vstor_packet);
1258 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
1259 		fc_host_node_name(stor_device->host) = stor_device->node_name;
1260 		fc_host_port_name(stor_device->host) = stor_device->port_name;
1261 #endif
1262 		break;
1263 	default:
1264 		break;
1265 	}
1266 }
1267 
1268 static void storvsc_on_channel_callback(void *context)
1269 {
1270 	struct vmbus_channel *channel = (struct vmbus_channel *)context;
1271 	const struct vmpacket_descriptor *desc;
1272 	struct hv_device *device;
1273 	struct storvsc_device *stor_device;
1274 	struct Scsi_Host *shost;
1275 
1276 	if (channel->primary_channel != NULL)
1277 		device = channel->primary_channel->device_obj;
1278 	else
1279 		device = channel->device_obj;
1280 
1281 	stor_device = get_in_stor_device(device);
1282 	if (!stor_device)
1283 		return;
1284 
1285 	shost = stor_device->host;
1286 
1287 	foreach_vmbus_pkt(desc, channel) {
1288 		struct vstor_packet *packet = hv_pkt_data(desc);
1289 		struct storvsc_cmd_request *request = NULL;
1290 		u32 pktlen = hv_pkt_datalen(desc);
1291 		u64 rqst_id = desc->trans_id;
1292 		u32 minlen = rqst_id ? sizeof(struct vstor_packet) -
1293 			stor_device->vmscsi_size_delta : sizeof(enum vstor_packet_operation);
1294 
1295 		if (pktlen < minlen) {
1296 			dev_err(&device->device,
1297 				"Invalid pkt: id=%llu, len=%u, minlen=%u\n",
1298 				rqst_id, pktlen, minlen);
1299 			continue;
1300 		}
1301 
1302 		if (rqst_id == VMBUS_RQST_INIT) {
1303 			request = &stor_device->init_request;
1304 		} else if (rqst_id == VMBUS_RQST_RESET) {
1305 			request = &stor_device->reset_request;
1306 		} else {
1307 			/* Hyper-V can send an unsolicited message with ID of 0 */
1308 			if (rqst_id == 0) {
1309 				/*
1310 				 * storvsc_on_receive() looks at the vstor_packet in the message
1311 				 * from the ring buffer.
1312 				 *
1313 				 * - If the operation in the vstor_packet is COMPLETE_IO, then
1314 				 *   we call storvsc_on_io_completion(), and dereference the
1315 				 *   guest memory address.  Make sure we don't call
1316 				 *   storvsc_on_io_completion() with a guest memory address
1317 				 *   that is zero if Hyper-V were to construct and send such
1318 				 *   a bogus packet.
1319 				 *
1320 				 * - If the operation in the vstor_packet is FCHBA_DATA, then
1321 				 *   we call cache_wwn(), and access the data payload area of
1322 				 *   the packet (wwn_packet); however, there is no guarantee
1323 				 *   that the packet is big enough to contain such area.
1324 				 *   Future-proof the code by rejecting such a bogus packet.
1325 				 */
1326 				if (packet->operation == VSTOR_OPERATION_COMPLETE_IO ||
1327 				    packet->operation == VSTOR_OPERATION_FCHBA_DATA) {
1328 					dev_err(&device->device, "Invalid packet with ID of 0\n");
1329 					continue;
1330 				}
1331 			} else {
1332 				struct scsi_cmnd *scmnd;
1333 
1334 				/* Transaction 'rqst_id' corresponds to tag 'rqst_id - 1' */
1335 				scmnd = scsi_host_find_tag(shost, rqst_id - 1);
1336 				if (scmnd == NULL) {
1337 					dev_err(&device->device, "Incorrect transaction ID\n");
1338 					continue;
1339 				}
1340 				request = (struct storvsc_cmd_request *)scsi_cmd_priv(scmnd);
1341 				scsi_dma_unmap(scmnd);
1342 			}
1343 
1344 			storvsc_on_receive(stor_device, packet, request);
1345 			continue;
1346 		}
1347 
1348 		memcpy(&request->vstor_packet, packet,
1349 		       (sizeof(struct vstor_packet) - stor_device->vmscsi_size_delta));
1350 		complete(&request->wait_event);
1351 	}
1352 }
1353 
1354 static int storvsc_connect_to_vsp(struct hv_device *device, u32 ring_size,
1355 				  bool is_fc)
1356 {
1357 	struct vmstorage_channel_properties props;
1358 	int ret;
1359 
1360 	memset(&props, 0, sizeof(struct vmstorage_channel_properties));
1361 
1362 	device->channel->max_pkt_size = STORVSC_MAX_PKT_SIZE;
1363 	device->channel->next_request_id_callback = storvsc_next_request_id;
1364 
1365 	ret = vmbus_open(device->channel,
1366 			 ring_size,
1367 			 ring_size,
1368 			 (void *)&props,
1369 			 sizeof(struct vmstorage_channel_properties),
1370 			 storvsc_on_channel_callback, device->channel);
1371 
1372 	if (ret != 0)
1373 		return ret;
1374 
1375 	ret = storvsc_channel_init(device, is_fc);
1376 
1377 	return ret;
1378 }
1379 
1380 static int storvsc_dev_remove(struct hv_device *device)
1381 {
1382 	struct storvsc_device *stor_device;
1383 
1384 	stor_device = hv_get_drvdata(device);
1385 
1386 	stor_device->destroy = true;
1387 
1388 	/* Make sure flag is set before waiting */
1389 	wmb();
1390 
1391 	/*
1392 	 * At this point, all outbound traffic should be disable. We
1393 	 * only allow inbound traffic (responses) to proceed so that
1394 	 * outstanding requests can be completed.
1395 	 */
1396 
1397 	storvsc_wait_to_drain(stor_device);
1398 
1399 	/*
1400 	 * Since we have already drained, we don't need to busy wait
1401 	 * as was done in final_release_stor_device()
1402 	 * Note that we cannot set the ext pointer to NULL until
1403 	 * we have drained - to drain the outgoing packets, we need to
1404 	 * allow incoming packets.
1405 	 */
1406 	hv_set_drvdata(device, NULL);
1407 
1408 	/* Close the channel */
1409 	vmbus_close(device->channel);
1410 
1411 	kfree(stor_device->stor_chns);
1412 	kfree(stor_device);
1413 	return 0;
1414 }
1415 
1416 static struct vmbus_channel *get_og_chn(struct storvsc_device *stor_device,
1417 					u16 q_num)
1418 {
1419 	u16 slot = 0;
1420 	u16 hash_qnum;
1421 	const struct cpumask *node_mask;
1422 	int num_channels, tgt_cpu;
1423 
1424 	if (stor_device->num_sc == 0) {
1425 		stor_device->stor_chns[q_num] = stor_device->device->channel;
1426 		return stor_device->device->channel;
1427 	}
1428 
1429 	/*
1430 	 * Our channel array is sparsley populated and we
1431 	 * initiated I/O on a processor/hw-q that does not
1432 	 * currently have a designated channel. Fix this.
1433 	 * The strategy is simple:
1434 	 * I. Ensure NUMA locality
1435 	 * II. Distribute evenly (best effort)
1436 	 */
1437 
1438 	node_mask = cpumask_of_node(cpu_to_node(q_num));
1439 
1440 	num_channels = 0;
1441 	for_each_cpu(tgt_cpu, &stor_device->alloced_cpus) {
1442 		if (cpumask_test_cpu(tgt_cpu, node_mask))
1443 			num_channels++;
1444 	}
1445 	if (num_channels == 0) {
1446 		stor_device->stor_chns[q_num] = stor_device->device->channel;
1447 		return stor_device->device->channel;
1448 	}
1449 
1450 	hash_qnum = q_num;
1451 	while (hash_qnum >= num_channels)
1452 		hash_qnum -= num_channels;
1453 
1454 	for_each_cpu(tgt_cpu, &stor_device->alloced_cpus) {
1455 		if (!cpumask_test_cpu(tgt_cpu, node_mask))
1456 			continue;
1457 		if (slot == hash_qnum)
1458 			break;
1459 		slot++;
1460 	}
1461 
1462 	stor_device->stor_chns[q_num] = stor_device->stor_chns[tgt_cpu];
1463 
1464 	return stor_device->stor_chns[q_num];
1465 }
1466 
1467 
1468 static int storvsc_do_io(struct hv_device *device,
1469 			 struct storvsc_cmd_request *request, u16 q_num)
1470 {
1471 	struct storvsc_device *stor_device;
1472 	struct vstor_packet *vstor_packet;
1473 	struct vmbus_channel *outgoing_channel, *channel;
1474 	unsigned long flags;
1475 	int ret = 0;
1476 	const struct cpumask *node_mask;
1477 	int tgt_cpu;
1478 
1479 	vstor_packet = &request->vstor_packet;
1480 	stor_device = get_out_stor_device(device);
1481 
1482 	if (!stor_device)
1483 		return -ENODEV;
1484 
1485 
1486 	request->device  = device;
1487 	/*
1488 	 * Select an appropriate channel to send the request out.
1489 	 */
1490 	/* See storvsc_change_target_cpu(). */
1491 	outgoing_channel = READ_ONCE(stor_device->stor_chns[q_num]);
1492 	if (outgoing_channel != NULL) {
1493 		if (outgoing_channel->target_cpu == q_num) {
1494 			/*
1495 			 * Ideally, we want to pick a different channel if
1496 			 * available on the same NUMA node.
1497 			 */
1498 			node_mask = cpumask_of_node(cpu_to_node(q_num));
1499 			for_each_cpu_wrap(tgt_cpu,
1500 				 &stor_device->alloced_cpus, q_num + 1) {
1501 				if (!cpumask_test_cpu(tgt_cpu, node_mask))
1502 					continue;
1503 				if (tgt_cpu == q_num)
1504 					continue;
1505 				channel = READ_ONCE(
1506 					stor_device->stor_chns[tgt_cpu]);
1507 				if (channel == NULL)
1508 					continue;
1509 				if (hv_get_avail_to_write_percent(
1510 							&channel->outbound)
1511 						> ring_avail_percent_lowater) {
1512 					outgoing_channel = channel;
1513 					goto found_channel;
1514 				}
1515 			}
1516 
1517 			/*
1518 			 * All the other channels on the same NUMA node are
1519 			 * busy. Try to use the channel on the current CPU
1520 			 */
1521 			if (hv_get_avail_to_write_percent(
1522 						&outgoing_channel->outbound)
1523 					> ring_avail_percent_lowater)
1524 				goto found_channel;
1525 
1526 			/*
1527 			 * If we reach here, all the channels on the current
1528 			 * NUMA node are busy. Try to find a channel in
1529 			 * other NUMA nodes
1530 			 */
1531 			for_each_cpu(tgt_cpu, &stor_device->alloced_cpus) {
1532 				if (cpumask_test_cpu(tgt_cpu, node_mask))
1533 					continue;
1534 				channel = READ_ONCE(
1535 					stor_device->stor_chns[tgt_cpu]);
1536 				if (channel == NULL)
1537 					continue;
1538 				if (hv_get_avail_to_write_percent(
1539 							&channel->outbound)
1540 						> ring_avail_percent_lowater) {
1541 					outgoing_channel = channel;
1542 					goto found_channel;
1543 				}
1544 			}
1545 		}
1546 	} else {
1547 		spin_lock_irqsave(&stor_device->lock, flags);
1548 		outgoing_channel = stor_device->stor_chns[q_num];
1549 		if (outgoing_channel != NULL) {
1550 			spin_unlock_irqrestore(&stor_device->lock, flags);
1551 			goto found_channel;
1552 		}
1553 		outgoing_channel = get_og_chn(stor_device, q_num);
1554 		spin_unlock_irqrestore(&stor_device->lock, flags);
1555 	}
1556 
1557 found_channel:
1558 	vstor_packet->flags |= REQUEST_COMPLETION_FLAG;
1559 
1560 	vstor_packet->vm_srb.length = (sizeof(struct vmscsi_request) -
1561 					stor_device->vmscsi_size_delta);
1562 
1563 
1564 	vstor_packet->vm_srb.sense_info_length = sense_buffer_size;
1565 
1566 
1567 	vstor_packet->vm_srb.data_transfer_length =
1568 	request->payload->range.len;
1569 
1570 	vstor_packet->operation = VSTOR_OPERATION_EXECUTE_SRB;
1571 
1572 	if (request->payload->range.len) {
1573 
1574 		ret = vmbus_sendpacket_mpb_desc(outgoing_channel,
1575 				request->payload, request->payload_sz,
1576 				vstor_packet,
1577 				(sizeof(struct vstor_packet) -
1578 				stor_device->vmscsi_size_delta),
1579 				(unsigned long)request);
1580 	} else {
1581 		ret = vmbus_sendpacket(outgoing_channel, vstor_packet,
1582 			       (sizeof(struct vstor_packet) -
1583 				stor_device->vmscsi_size_delta),
1584 			       (unsigned long)request,
1585 			       VM_PKT_DATA_INBAND,
1586 			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
1587 	}
1588 
1589 	if (ret != 0)
1590 		return ret;
1591 
1592 	atomic_inc(&stor_device->num_outstanding_req);
1593 
1594 	return ret;
1595 }
1596 
1597 static int storvsc_device_alloc(struct scsi_device *sdevice)
1598 {
1599 	/*
1600 	 * Set blist flag to permit the reading of the VPD pages even when
1601 	 * the target may claim SPC-2 compliance. MSFT targets currently
1602 	 * claim SPC-2 compliance while they implement post SPC-2 features.
1603 	 * With this flag we can correctly handle WRITE_SAME_16 issues.
1604 	 *
1605 	 * Hypervisor reports SCSI_UNKNOWN type for DVD ROM device but
1606 	 * still supports REPORT LUN.
1607 	 */
1608 	sdevice->sdev_bflags = BLIST_REPORTLUN2 | BLIST_TRY_VPD_PAGES;
1609 
1610 	return 0;
1611 }
1612 
1613 static int storvsc_device_configure(struct scsi_device *sdevice)
1614 {
1615 	blk_queue_rq_timeout(sdevice->request_queue, (storvsc_timeout * HZ));
1616 
1617 	sdevice->no_write_same = 1;
1618 
1619 	/*
1620 	 * If the host is WIN8 or WIN8 R2, claim conformance to SPC-3
1621 	 * if the device is a MSFT virtual device.  If the host is
1622 	 * WIN10 or newer, allow write_same.
1623 	 */
1624 	if (!strncmp(sdevice->vendor, "Msft", 4)) {
1625 		switch (vmstor_proto_version) {
1626 		case VMSTOR_PROTO_VERSION_WIN8:
1627 		case VMSTOR_PROTO_VERSION_WIN8_1:
1628 			sdevice->scsi_level = SCSI_SPC_3;
1629 			break;
1630 		}
1631 
1632 		if (vmstor_proto_version >= VMSTOR_PROTO_VERSION_WIN10)
1633 			sdevice->no_write_same = 0;
1634 	}
1635 
1636 	return 0;
1637 }
1638 
1639 static int storvsc_get_chs(struct scsi_device *sdev, struct block_device * bdev,
1640 			   sector_t capacity, int *info)
1641 {
1642 	sector_t nsect = capacity;
1643 	sector_t cylinders = nsect;
1644 	int heads, sectors_pt;
1645 
1646 	/*
1647 	 * We are making up these values; let us keep it simple.
1648 	 */
1649 	heads = 0xff;
1650 	sectors_pt = 0x3f;      /* Sectors per track */
1651 	sector_div(cylinders, heads * sectors_pt);
1652 	if ((sector_t)(cylinders + 1) * heads * sectors_pt < nsect)
1653 		cylinders = 0xffff;
1654 
1655 	info[0] = heads;
1656 	info[1] = sectors_pt;
1657 	info[2] = (int)cylinders;
1658 
1659 	return 0;
1660 }
1661 
1662 static int storvsc_host_reset_handler(struct scsi_cmnd *scmnd)
1663 {
1664 	struct hv_host_device *host_dev = shost_priv(scmnd->device->host);
1665 	struct hv_device *device = host_dev->dev;
1666 
1667 	struct storvsc_device *stor_device;
1668 	struct storvsc_cmd_request *request;
1669 	struct vstor_packet *vstor_packet;
1670 	int ret, t;
1671 
1672 	stor_device = get_out_stor_device(device);
1673 	if (!stor_device)
1674 		return FAILED;
1675 
1676 	request = &stor_device->reset_request;
1677 	vstor_packet = &request->vstor_packet;
1678 	memset(vstor_packet, 0, sizeof(struct vstor_packet));
1679 
1680 	init_completion(&request->wait_event);
1681 
1682 	vstor_packet->operation = VSTOR_OPERATION_RESET_BUS;
1683 	vstor_packet->flags = REQUEST_COMPLETION_FLAG;
1684 	vstor_packet->vm_srb.path_id = stor_device->path_id;
1685 
1686 	ret = vmbus_sendpacket(device->channel, vstor_packet,
1687 			       (sizeof(struct vstor_packet) -
1688 				stor_device->vmscsi_size_delta),
1689 			       VMBUS_RQST_RESET,
1690 			       VM_PKT_DATA_INBAND,
1691 			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
1692 	if (ret != 0)
1693 		return FAILED;
1694 
1695 	t = wait_for_completion_timeout(&request->wait_event, 5*HZ);
1696 	if (t == 0)
1697 		return TIMEOUT_ERROR;
1698 
1699 
1700 	/*
1701 	 * At this point, all outstanding requests in the adapter
1702 	 * should have been flushed out and return to us
1703 	 * There is a potential race here where the host may be in
1704 	 * the process of responding when we return from here.
1705 	 * Just wait for all in-transit packets to be accounted for
1706 	 * before we return from here.
1707 	 */
1708 	storvsc_wait_to_drain(stor_device);
1709 
1710 	return SUCCESS;
1711 }
1712 
1713 /*
1714  * The host guarantees to respond to each command, although I/O latencies might
1715  * be unbounded on Azure.  Reset the timer unconditionally to give the host a
1716  * chance to perform EH.
1717  */
1718 static enum blk_eh_timer_return storvsc_eh_timed_out(struct scsi_cmnd *scmnd)
1719 {
1720 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
1721 	if (scmnd->device->host->transportt == fc_transport_template)
1722 		return fc_eh_timed_out(scmnd);
1723 #endif
1724 	return BLK_EH_RESET_TIMER;
1725 }
1726 
1727 static bool storvsc_scsi_cmd_ok(struct scsi_cmnd *scmnd)
1728 {
1729 	bool allowed = true;
1730 	u8 scsi_op = scmnd->cmnd[0];
1731 
1732 	switch (scsi_op) {
1733 	/* the host does not handle WRITE_SAME, log accident usage */
1734 	case WRITE_SAME:
1735 	/*
1736 	 * smartd sends this command and the host does not handle
1737 	 * this. So, don't send it.
1738 	 */
1739 	case SET_WINDOW:
1740 		set_host_byte(scmnd, DID_ERROR);
1741 		allowed = false;
1742 		break;
1743 	default:
1744 		break;
1745 	}
1746 	return allowed;
1747 }
1748 
1749 static int storvsc_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *scmnd)
1750 {
1751 	int ret;
1752 	struct hv_host_device *host_dev = shost_priv(host);
1753 	struct hv_device *dev = host_dev->dev;
1754 	struct storvsc_cmd_request *cmd_request = scsi_cmd_priv(scmnd);
1755 	struct scatterlist *sgl;
1756 	struct vmscsi_request *vm_srb;
1757 	struct vmbus_packet_mpb_array  *payload;
1758 	u32 payload_sz;
1759 	u32 length;
1760 
1761 	if (vmstor_proto_version <= VMSTOR_PROTO_VERSION_WIN8) {
1762 		/*
1763 		 * On legacy hosts filter unimplemented commands.
1764 		 * Future hosts are expected to correctly handle
1765 		 * unsupported commands. Furthermore, it is
1766 		 * possible that some of the currently
1767 		 * unsupported commands maybe supported in
1768 		 * future versions of the host.
1769 		 */
1770 		if (!storvsc_scsi_cmd_ok(scmnd)) {
1771 			scsi_done(scmnd);
1772 			return 0;
1773 		}
1774 	}
1775 
1776 	/* Setup the cmd request */
1777 	cmd_request->cmd = scmnd;
1778 
1779 	memset(&cmd_request->vstor_packet, 0, sizeof(struct vstor_packet));
1780 	vm_srb = &cmd_request->vstor_packet.vm_srb;
1781 	vm_srb->win8_extension.time_out_value = 60;
1782 
1783 	vm_srb->win8_extension.srb_flags |=
1784 		SRB_FLAGS_DISABLE_SYNCH_TRANSFER;
1785 
1786 	if (scmnd->device->tagged_supported) {
1787 		vm_srb->win8_extension.srb_flags |=
1788 		(SRB_FLAGS_QUEUE_ACTION_ENABLE | SRB_FLAGS_NO_QUEUE_FREEZE);
1789 		vm_srb->win8_extension.queue_tag = SP_UNTAGGED;
1790 		vm_srb->win8_extension.queue_action = SRB_SIMPLE_TAG_REQUEST;
1791 	}
1792 
1793 	/* Build the SRB */
1794 	switch (scmnd->sc_data_direction) {
1795 	case DMA_TO_DEVICE:
1796 		vm_srb->data_in = WRITE_TYPE;
1797 		vm_srb->win8_extension.srb_flags |= SRB_FLAGS_DATA_OUT;
1798 		break;
1799 	case DMA_FROM_DEVICE:
1800 		vm_srb->data_in = READ_TYPE;
1801 		vm_srb->win8_extension.srb_flags |= SRB_FLAGS_DATA_IN;
1802 		break;
1803 	case DMA_NONE:
1804 		vm_srb->data_in = UNKNOWN_TYPE;
1805 		vm_srb->win8_extension.srb_flags |= SRB_FLAGS_NO_DATA_TRANSFER;
1806 		break;
1807 	default:
1808 		/*
1809 		 * This is DMA_BIDIRECTIONAL or something else we are never
1810 		 * supposed to see here.
1811 		 */
1812 		WARN(1, "Unexpected data direction: %d\n",
1813 		     scmnd->sc_data_direction);
1814 		return -EINVAL;
1815 	}
1816 
1817 
1818 	vm_srb->port_number = host_dev->port;
1819 	vm_srb->path_id = scmnd->device->channel;
1820 	vm_srb->target_id = scmnd->device->id;
1821 	vm_srb->lun = scmnd->device->lun;
1822 
1823 	vm_srb->cdb_length = scmnd->cmd_len;
1824 
1825 	memcpy(vm_srb->cdb, scmnd->cmnd, vm_srb->cdb_length);
1826 
1827 	sgl = (struct scatterlist *)scsi_sglist(scmnd);
1828 
1829 	length = scsi_bufflen(scmnd);
1830 	payload = (struct vmbus_packet_mpb_array *)&cmd_request->mpb;
1831 	payload_sz = sizeof(cmd_request->mpb);
1832 
1833 	if (scsi_sg_count(scmnd)) {
1834 		unsigned long offset_in_hvpg = offset_in_hvpage(sgl->offset);
1835 		unsigned int hvpg_count = HVPFN_UP(offset_in_hvpg + length);
1836 		struct scatterlist *sg;
1837 		unsigned long hvpfn, hvpfns_to_add;
1838 		int j, i = 0, sg_count;
1839 
1840 		if (hvpg_count > MAX_PAGE_BUFFER_COUNT) {
1841 
1842 			payload_sz = (hvpg_count * sizeof(u64) +
1843 				      sizeof(struct vmbus_packet_mpb_array));
1844 			payload = kzalloc(payload_sz, GFP_ATOMIC);
1845 			if (!payload)
1846 				return SCSI_MLQUEUE_DEVICE_BUSY;
1847 		}
1848 
1849 		payload->range.len = length;
1850 		payload->range.offset = offset_in_hvpg;
1851 
1852 		sg_count = scsi_dma_map(scmnd);
1853 		if (sg_count < 0) {
1854 			ret = SCSI_MLQUEUE_DEVICE_BUSY;
1855 			goto err_free_payload;
1856 		}
1857 
1858 		for_each_sg(sgl, sg, sg_count, j) {
1859 			/*
1860 			 * Init values for the current sgl entry. hvpfns_to_add
1861 			 * is in units of Hyper-V size pages. Handling the
1862 			 * PAGE_SIZE != HV_HYP_PAGE_SIZE case also handles
1863 			 * values of sgl->offset that are larger than PAGE_SIZE.
1864 			 * Such offsets are handled even on other than the first
1865 			 * sgl entry, provided they are a multiple of PAGE_SIZE.
1866 			 */
1867 			hvpfn = HVPFN_DOWN(sg_dma_address(sg));
1868 			hvpfns_to_add = HVPFN_UP(sg_dma_address(sg) +
1869 						 sg_dma_len(sg)) - hvpfn;
1870 
1871 			/*
1872 			 * Fill the next portion of the PFN array with
1873 			 * sequential Hyper-V PFNs for the continguous physical
1874 			 * memory described by the sgl entry. The end of the
1875 			 * last sgl should be reached at the same time that
1876 			 * the PFN array is filled.
1877 			 */
1878 			while (hvpfns_to_add--)
1879 				payload->range.pfn_array[i++] = hvpfn++;
1880 		}
1881 	}
1882 
1883 	cmd_request->payload = payload;
1884 	cmd_request->payload_sz = payload_sz;
1885 
1886 	/* Invokes the vsc to start an IO */
1887 	ret = storvsc_do_io(dev, cmd_request, get_cpu());
1888 	put_cpu();
1889 
1890 	if (ret == -EAGAIN) {
1891 		/* no more space */
1892 		ret = SCSI_MLQUEUE_DEVICE_BUSY;
1893 		goto err_free_payload;
1894 	}
1895 
1896 	return 0;
1897 
1898 err_free_payload:
1899 	if (payload_sz > sizeof(cmd_request->mpb))
1900 		kfree(payload);
1901 
1902 	return ret;
1903 }
1904 
1905 static struct scsi_host_template scsi_driver = {
1906 	.module	=		THIS_MODULE,
1907 	.name =			"storvsc_host_t",
1908 	.cmd_size =             sizeof(struct storvsc_cmd_request),
1909 	.bios_param =		storvsc_get_chs,
1910 	.queuecommand =		storvsc_queuecommand,
1911 	.eh_host_reset_handler =	storvsc_host_reset_handler,
1912 	.proc_name =		"storvsc_host",
1913 	.eh_timed_out =		storvsc_eh_timed_out,
1914 	.slave_alloc =		storvsc_device_alloc,
1915 	.slave_configure =	storvsc_device_configure,
1916 	.cmd_per_lun =		2048,
1917 	.this_id =		-1,
1918 	/* Ensure there are no gaps in presented sgls */
1919 	.virt_boundary_mask =	PAGE_SIZE-1,
1920 	.no_write_same =	1,
1921 	.track_queue_depth =	1,
1922 	.change_queue_depth =	storvsc_change_queue_depth,
1923 };
1924 
1925 enum {
1926 	SCSI_GUID,
1927 	IDE_GUID,
1928 	SFC_GUID,
1929 };
1930 
1931 static const struct hv_vmbus_device_id id_table[] = {
1932 	/* SCSI guid */
1933 	{ HV_SCSI_GUID,
1934 	  .driver_data = SCSI_GUID
1935 	},
1936 	/* IDE guid */
1937 	{ HV_IDE_GUID,
1938 	  .driver_data = IDE_GUID
1939 	},
1940 	/* Fibre Channel GUID */
1941 	{
1942 	  HV_SYNTHFC_GUID,
1943 	  .driver_data = SFC_GUID
1944 	},
1945 	{ },
1946 };
1947 
1948 MODULE_DEVICE_TABLE(vmbus, id_table);
1949 
1950 static const struct { guid_t guid; } fc_guid = { HV_SYNTHFC_GUID };
1951 
1952 static bool hv_dev_is_fc(struct hv_device *hv_dev)
1953 {
1954 	return guid_equal(&fc_guid.guid, &hv_dev->dev_type);
1955 }
1956 
1957 static int storvsc_probe(struct hv_device *device,
1958 			const struct hv_vmbus_device_id *dev_id)
1959 {
1960 	int ret;
1961 	int num_cpus = num_online_cpus();
1962 	int num_present_cpus = num_present_cpus();
1963 	struct Scsi_Host *host;
1964 	struct hv_host_device *host_dev;
1965 	bool dev_is_ide = ((dev_id->driver_data == IDE_GUID) ? true : false);
1966 	bool is_fc = ((dev_id->driver_data == SFC_GUID) ? true : false);
1967 	int target = 0;
1968 	struct storvsc_device *stor_device;
1969 	int max_luns_per_target;
1970 	int max_targets;
1971 	int max_channels;
1972 	int max_sub_channels = 0;
1973 
1974 	/*
1975 	 * Based on the windows host we are running on,
1976 	 * set state to properly communicate with the host.
1977 	 */
1978 
1979 	if (vmbus_proto_version < VERSION_WIN8) {
1980 		max_luns_per_target = STORVSC_IDE_MAX_LUNS_PER_TARGET;
1981 		max_targets = STORVSC_IDE_MAX_TARGETS;
1982 		max_channels = STORVSC_IDE_MAX_CHANNELS;
1983 	} else {
1984 		max_luns_per_target = STORVSC_MAX_LUNS_PER_TARGET;
1985 		max_targets = STORVSC_MAX_TARGETS;
1986 		max_channels = STORVSC_MAX_CHANNELS;
1987 		/*
1988 		 * On Windows8 and above, we support sub-channels for storage
1989 		 * on SCSI and FC controllers.
1990 		 * The number of sub-channels offerred is based on the number of
1991 		 * VCPUs in the guest.
1992 		 */
1993 		if (!dev_is_ide)
1994 			max_sub_channels =
1995 				(num_cpus - 1) / storvsc_vcpus_per_sub_channel;
1996 	}
1997 
1998 	scsi_driver.can_queue = max_outstanding_req_per_channel *
1999 				(max_sub_channels + 1) *
2000 				(100 - ring_avail_percent_lowater) / 100;
2001 
2002 	host = scsi_host_alloc(&scsi_driver,
2003 			       sizeof(struct hv_host_device));
2004 	if (!host)
2005 		return -ENOMEM;
2006 
2007 	host_dev = shost_priv(host);
2008 	memset(host_dev, 0, sizeof(struct hv_host_device));
2009 
2010 	host_dev->port = host->host_no;
2011 	host_dev->dev = device;
2012 	host_dev->host = host;
2013 
2014 
2015 	stor_device = kzalloc(sizeof(struct storvsc_device), GFP_KERNEL);
2016 	if (!stor_device) {
2017 		ret = -ENOMEM;
2018 		goto err_out0;
2019 	}
2020 
2021 	stor_device->destroy = false;
2022 	init_waitqueue_head(&stor_device->waiting_to_drain);
2023 	stor_device->device = device;
2024 	stor_device->host = host;
2025 	stor_device->vmscsi_size_delta = sizeof(struct vmscsi_win8_extension);
2026 	spin_lock_init(&stor_device->lock);
2027 	hv_set_drvdata(device, stor_device);
2028 	dma_set_min_align_mask(&device->device, HV_HYP_PAGE_SIZE - 1);
2029 
2030 	stor_device->port_number = host->host_no;
2031 	ret = storvsc_connect_to_vsp(device, storvsc_ringbuffer_size, is_fc);
2032 	if (ret)
2033 		goto err_out1;
2034 
2035 	host_dev->path = stor_device->path_id;
2036 	host_dev->target = stor_device->target_id;
2037 
2038 	switch (dev_id->driver_data) {
2039 	case SFC_GUID:
2040 		host->max_lun = STORVSC_FC_MAX_LUNS_PER_TARGET;
2041 		host->max_id = STORVSC_FC_MAX_TARGETS;
2042 		host->max_channel = STORVSC_FC_MAX_CHANNELS - 1;
2043 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
2044 		host->transportt = fc_transport_template;
2045 #endif
2046 		break;
2047 
2048 	case SCSI_GUID:
2049 		host->max_lun = max_luns_per_target;
2050 		host->max_id = max_targets;
2051 		host->max_channel = max_channels - 1;
2052 		break;
2053 
2054 	default:
2055 		host->max_lun = STORVSC_IDE_MAX_LUNS_PER_TARGET;
2056 		host->max_id = STORVSC_IDE_MAX_TARGETS;
2057 		host->max_channel = STORVSC_IDE_MAX_CHANNELS - 1;
2058 		break;
2059 	}
2060 	/* max cmd length */
2061 	host->max_cmd_len = STORVSC_MAX_CMD_LEN;
2062 
2063 	/*
2064 	 * set the table size based on the info we got
2065 	 * from the host.
2066 	 */
2067 	host->sg_tablesize = (stor_device->max_transfer_bytes >> PAGE_SHIFT);
2068 	/*
2069 	 * For non-IDE disks, the host supports multiple channels.
2070 	 * Set the number of HW queues we are supporting.
2071 	 */
2072 	if (!dev_is_ide) {
2073 		if (storvsc_max_hw_queues > num_present_cpus) {
2074 			storvsc_max_hw_queues = 0;
2075 			storvsc_log(device, STORVSC_LOGGING_WARN,
2076 				"Resetting invalid storvsc_max_hw_queues value to default.\n");
2077 		}
2078 		if (storvsc_max_hw_queues)
2079 			host->nr_hw_queues = storvsc_max_hw_queues;
2080 		else
2081 			host->nr_hw_queues = num_present_cpus;
2082 	}
2083 
2084 	/*
2085 	 * Set the error handler work queue.
2086 	 */
2087 	host_dev->handle_error_wq =
2088 			alloc_ordered_workqueue("storvsc_error_wq_%d",
2089 						WQ_MEM_RECLAIM,
2090 						host->host_no);
2091 	if (!host_dev->handle_error_wq) {
2092 		ret = -ENOMEM;
2093 		goto err_out2;
2094 	}
2095 	INIT_WORK(&host_dev->host_scan_work, storvsc_host_scan);
2096 	/* Register the HBA and start the scsi bus scan */
2097 	ret = scsi_add_host(host, &device->device);
2098 	if (ret != 0)
2099 		goto err_out3;
2100 
2101 	if (!dev_is_ide) {
2102 		scsi_scan_host(host);
2103 	} else {
2104 		target = (device->dev_instance.b[5] << 8 |
2105 			 device->dev_instance.b[4]);
2106 		ret = scsi_add_device(host, 0, target, 0);
2107 		if (ret)
2108 			goto err_out4;
2109 	}
2110 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
2111 	if (host->transportt == fc_transport_template) {
2112 		struct fc_rport_identifiers ids = {
2113 			.roles = FC_PORT_ROLE_FCP_DUMMY_INITIATOR,
2114 		};
2115 
2116 		fc_host_node_name(host) = stor_device->node_name;
2117 		fc_host_port_name(host) = stor_device->port_name;
2118 		stor_device->rport = fc_remote_port_add(host, 0, &ids);
2119 		if (!stor_device->rport) {
2120 			ret = -ENOMEM;
2121 			goto err_out4;
2122 		}
2123 	}
2124 #endif
2125 	return 0;
2126 
2127 err_out4:
2128 	scsi_remove_host(host);
2129 
2130 err_out3:
2131 	destroy_workqueue(host_dev->handle_error_wq);
2132 
2133 err_out2:
2134 	/*
2135 	 * Once we have connected with the host, we would need to
2136 	 * to invoke storvsc_dev_remove() to rollback this state and
2137 	 * this call also frees up the stor_device; hence the jump around
2138 	 * err_out1 label.
2139 	 */
2140 	storvsc_dev_remove(device);
2141 	goto err_out0;
2142 
2143 err_out1:
2144 	kfree(stor_device->stor_chns);
2145 	kfree(stor_device);
2146 
2147 err_out0:
2148 	scsi_host_put(host);
2149 	return ret;
2150 }
2151 
2152 /* Change a scsi target's queue depth */
2153 static int storvsc_change_queue_depth(struct scsi_device *sdev, int queue_depth)
2154 {
2155 	if (queue_depth > scsi_driver.can_queue)
2156 		queue_depth = scsi_driver.can_queue;
2157 
2158 	return scsi_change_queue_depth(sdev, queue_depth);
2159 }
2160 
2161 static int storvsc_remove(struct hv_device *dev)
2162 {
2163 	struct storvsc_device *stor_device = hv_get_drvdata(dev);
2164 	struct Scsi_Host *host = stor_device->host;
2165 	struct hv_host_device *host_dev = shost_priv(host);
2166 
2167 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
2168 	if (host->transportt == fc_transport_template) {
2169 		fc_remote_port_delete(stor_device->rport);
2170 		fc_remove_host(host);
2171 	}
2172 #endif
2173 	destroy_workqueue(host_dev->handle_error_wq);
2174 	scsi_remove_host(host);
2175 	storvsc_dev_remove(dev);
2176 	scsi_host_put(host);
2177 
2178 	return 0;
2179 }
2180 
2181 static int storvsc_suspend(struct hv_device *hv_dev)
2182 {
2183 	struct storvsc_device *stor_device = hv_get_drvdata(hv_dev);
2184 	struct Scsi_Host *host = stor_device->host;
2185 	struct hv_host_device *host_dev = shost_priv(host);
2186 
2187 	storvsc_wait_to_drain(stor_device);
2188 
2189 	drain_workqueue(host_dev->handle_error_wq);
2190 
2191 	vmbus_close(hv_dev->channel);
2192 
2193 	kfree(stor_device->stor_chns);
2194 	stor_device->stor_chns = NULL;
2195 
2196 	cpumask_clear(&stor_device->alloced_cpus);
2197 
2198 	return 0;
2199 }
2200 
2201 static int storvsc_resume(struct hv_device *hv_dev)
2202 {
2203 	int ret;
2204 
2205 	ret = storvsc_connect_to_vsp(hv_dev, storvsc_ringbuffer_size,
2206 				     hv_dev_is_fc(hv_dev));
2207 	return ret;
2208 }
2209 
2210 static struct hv_driver storvsc_drv = {
2211 	.name = KBUILD_MODNAME,
2212 	.id_table = id_table,
2213 	.probe = storvsc_probe,
2214 	.remove = storvsc_remove,
2215 	.suspend = storvsc_suspend,
2216 	.resume = storvsc_resume,
2217 	.driver = {
2218 		.probe_type = PROBE_PREFER_ASYNCHRONOUS,
2219 	},
2220 };
2221 
2222 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
2223 static struct fc_function_template fc_transport_functions = {
2224 	.show_host_node_name = 1,
2225 	.show_host_port_name = 1,
2226 };
2227 #endif
2228 
2229 static int __init storvsc_drv_init(void)
2230 {
2231 	int ret;
2232 
2233 	/*
2234 	 * Divide the ring buffer data size (which is 1 page less
2235 	 * than the ring buffer size since that page is reserved for
2236 	 * the ring buffer indices) by the max request size (which is
2237 	 * vmbus_channel_packet_multipage_buffer + struct vstor_packet + u64)
2238 	 *
2239 	 * The computation underestimates max_outstanding_req_per_channel
2240 	 * for Win7 and older hosts because it does not take into account
2241 	 * the vmscsi_size_delta correction to the max request size.
2242 	 */
2243 	max_outstanding_req_per_channel =
2244 		((storvsc_ringbuffer_size - PAGE_SIZE) /
2245 		ALIGN(MAX_MULTIPAGE_BUFFER_PACKET +
2246 		sizeof(struct vstor_packet) + sizeof(u64),
2247 		sizeof(u64)));
2248 
2249 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
2250 	fc_transport_template = fc_attach_transport(&fc_transport_functions);
2251 	if (!fc_transport_template)
2252 		return -ENODEV;
2253 #endif
2254 
2255 	ret = vmbus_driver_register(&storvsc_drv);
2256 
2257 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
2258 	if (ret)
2259 		fc_release_transport(fc_transport_template);
2260 #endif
2261 
2262 	return ret;
2263 }
2264 
2265 static void __exit storvsc_drv_exit(void)
2266 {
2267 	vmbus_driver_unregister(&storvsc_drv);
2268 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
2269 	fc_release_transport(fc_transport_template);
2270 #endif
2271 }
2272 
2273 MODULE_LICENSE("GPL");
2274 MODULE_DESCRIPTION("Microsoft Hyper-V virtual storage driver");
2275 module_init(storvsc_drv_init);
2276 module_exit(storvsc_drv_exit);
2277