xref: /openbmc/linux/drivers/scsi/storvsc_drv.c (revision 46290c6b)
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 #define VMSTOR_PROTO_VERSION_WIN6	VMSTOR_PROTO_VERSION(2, 0)
58 #define VMSTOR_PROTO_VERSION_WIN7	VMSTOR_PROTO_VERSION(4, 2)
59 #define VMSTOR_PROTO_VERSION_WIN8	VMSTOR_PROTO_VERSION(5, 1)
60 #define VMSTOR_PROTO_VERSION_WIN8_1	VMSTOR_PROTO_VERSION(6, 0)
61 #define VMSTOR_PROTO_VERSION_WIN10	VMSTOR_PROTO_VERSION(6, 2)
62 
63 /* channel callback timeout in ms */
64 #define CALLBACK_TIMEOUT               2
65 
66 /*  Packet structure describing virtual storage requests. */
67 enum vstor_packet_operation {
68 	VSTOR_OPERATION_COMPLETE_IO		= 1,
69 	VSTOR_OPERATION_REMOVE_DEVICE		= 2,
70 	VSTOR_OPERATION_EXECUTE_SRB		= 3,
71 	VSTOR_OPERATION_RESET_LUN		= 4,
72 	VSTOR_OPERATION_RESET_ADAPTER		= 5,
73 	VSTOR_OPERATION_RESET_BUS		= 6,
74 	VSTOR_OPERATION_BEGIN_INITIALIZATION	= 7,
75 	VSTOR_OPERATION_END_INITIALIZATION	= 8,
76 	VSTOR_OPERATION_QUERY_PROTOCOL_VERSION	= 9,
77 	VSTOR_OPERATION_QUERY_PROPERTIES	= 10,
78 	VSTOR_OPERATION_ENUMERATE_BUS		= 11,
79 	VSTOR_OPERATION_FCHBA_DATA              = 12,
80 	VSTOR_OPERATION_CREATE_SUB_CHANNELS     = 13,
81 	VSTOR_OPERATION_MAXIMUM                 = 13
82 };
83 
84 /*
85  * WWN packet for Fibre Channel HBA
86  */
87 
88 struct hv_fc_wwn_packet {
89 	u8	primary_active;
90 	u8	reserved1[3];
91 	u8	primary_port_wwn[8];
92 	u8	primary_node_wwn[8];
93 	u8	secondary_port_wwn[8];
94 	u8	secondary_node_wwn[8];
95 };
96 
97 
98 
99 /*
100  * SRB Flag Bits
101  */
102 
103 #define SRB_FLAGS_QUEUE_ACTION_ENABLE		0x00000002
104 #define SRB_FLAGS_DISABLE_DISCONNECT		0x00000004
105 #define SRB_FLAGS_DISABLE_SYNCH_TRANSFER	0x00000008
106 #define SRB_FLAGS_BYPASS_FROZEN_QUEUE		0x00000010
107 #define SRB_FLAGS_DISABLE_AUTOSENSE		0x00000020
108 #define SRB_FLAGS_DATA_IN			0x00000040
109 #define SRB_FLAGS_DATA_OUT			0x00000080
110 #define SRB_FLAGS_NO_DATA_TRANSFER		0x00000000
111 #define SRB_FLAGS_UNSPECIFIED_DIRECTION	(SRB_FLAGS_DATA_IN | SRB_FLAGS_DATA_OUT)
112 #define SRB_FLAGS_NO_QUEUE_FREEZE		0x00000100
113 #define SRB_FLAGS_ADAPTER_CACHE_ENABLE		0x00000200
114 #define SRB_FLAGS_FREE_SENSE_BUFFER		0x00000400
115 
116 /*
117  * This flag indicates the request is part of the workflow for processing a D3.
118  */
119 #define SRB_FLAGS_D3_PROCESSING			0x00000800
120 #define SRB_FLAGS_IS_ACTIVE			0x00010000
121 #define SRB_FLAGS_ALLOCATED_FROM_ZONE		0x00020000
122 #define SRB_FLAGS_SGLIST_FROM_POOL		0x00040000
123 #define SRB_FLAGS_BYPASS_LOCKED_QUEUE		0x00080000
124 #define SRB_FLAGS_NO_KEEP_AWAKE			0x00100000
125 #define SRB_FLAGS_PORT_DRIVER_ALLOCSENSE	0x00200000
126 #define SRB_FLAGS_PORT_DRIVER_SENSEHASPORT	0x00400000
127 #define SRB_FLAGS_DONT_START_NEXT_PACKET	0x00800000
128 #define SRB_FLAGS_PORT_DRIVER_RESERVED		0x0F000000
129 #define SRB_FLAGS_CLASS_DRIVER_RESERVED		0xF0000000
130 
131 #define SP_UNTAGGED			((unsigned char) ~0)
132 #define SRB_SIMPLE_TAG_REQUEST		0x20
133 
134 /*
135  * Platform neutral description of a scsi request -
136  * this remains the same across the write regardless of 32/64 bit
137  * note: it's patterned off the SCSI_PASS_THROUGH structure
138  */
139 #define STORVSC_MAX_CMD_LEN			0x10
140 
141 /* Sense buffer size is the same for all versions since Windows 8 */
142 #define STORVSC_SENSE_BUFFER_SIZE		0x14
143 #define STORVSC_MAX_BUF_LEN_WITH_PADDING	0x14
144 
145 /*
146  * The storage protocol version is determined during the
147  * initial exchange with the host.  It will indicate which
148  * storage functionality is available in the host.
149 */
150 static int vmstor_proto_version;
151 
152 #define STORVSC_LOGGING_NONE	0
153 #define STORVSC_LOGGING_ERROR	1
154 #define STORVSC_LOGGING_WARN	2
155 
156 static int logging_level = STORVSC_LOGGING_ERROR;
157 module_param(logging_level, int, S_IRUGO|S_IWUSR);
158 MODULE_PARM_DESC(logging_level,
159 	"Logging level, 0 - None, 1 - Error (default), 2 - Warning.");
160 
161 static inline bool do_logging(int level)
162 {
163 	return logging_level >= level;
164 }
165 
166 #define storvsc_log(dev, level, fmt, ...)			\
167 do {								\
168 	if (do_logging(level))					\
169 		dev_warn(&(dev)->device, fmt, ##__VA_ARGS__);	\
170 } while (0)
171 
172 struct vmscsi_request {
173 	u16 length;
174 	u8 srb_status;
175 	u8 scsi_status;
176 
177 	u8  port_number;
178 	u8  path_id;
179 	u8  target_id;
180 	u8  lun;
181 
182 	u8  cdb_length;
183 	u8  sense_info_length;
184 	u8  data_in;
185 	u8  reserved;
186 
187 	u32 data_transfer_length;
188 
189 	union {
190 		u8 cdb[STORVSC_MAX_CMD_LEN];
191 		u8 sense_data[STORVSC_SENSE_BUFFER_SIZE];
192 		u8 reserved_array[STORVSC_MAX_BUF_LEN_WITH_PADDING];
193 	};
194 	/*
195 	 * The following was added in win8.
196 	 */
197 	u16 reserve;
198 	u8  queue_tag;
199 	u8  queue_action;
200 	u32 srb_flags;
201 	u32 time_out_value;
202 	u32 queue_sort_ey;
203 
204 } __attribute((packed));
205 
206 /*
207  * The list of windows version in order of preference.
208  */
209 
210 static const int protocol_version[] = {
211 		VMSTOR_PROTO_VERSION_WIN10,
212 		VMSTOR_PROTO_VERSION_WIN8_1,
213 		VMSTOR_PROTO_VERSION_WIN8,
214 };
215 
216 
217 /*
218  * This structure is sent during the initialization phase to get the different
219  * properties of the channel.
220  */
221 
222 #define STORAGE_CHANNEL_SUPPORTS_MULTI_CHANNEL		0x1
223 
224 struct vmstorage_channel_properties {
225 	u32 reserved;
226 	u16 max_channel_cnt;
227 	u16 reserved1;
228 
229 	u32 flags;
230 	u32   max_transfer_bytes;
231 
232 	u64  reserved2;
233 } __packed;
234 
235 /*  This structure is sent during the storage protocol negotiations. */
236 struct vmstorage_protocol_version {
237 	/* Major (MSW) and minor (LSW) version numbers. */
238 	u16 major_minor;
239 
240 	/*
241 	 * Revision number is auto-incremented whenever this file is changed
242 	 * (See FILL_VMSTOR_REVISION macro above).  Mismatch does not
243 	 * definitely indicate incompatibility--but it does indicate mismatched
244 	 * builds.
245 	 * This is only used on the windows side. Just set it to 0.
246 	 */
247 	u16 revision;
248 } __packed;
249 
250 /* Channel Property Flags */
251 #define STORAGE_CHANNEL_REMOVABLE_FLAG		0x1
252 #define STORAGE_CHANNEL_EMULATED_IDE_FLAG	0x2
253 
254 struct vstor_packet {
255 	/* Requested operation type */
256 	enum vstor_packet_operation operation;
257 
258 	/*  Flags - see below for values */
259 	u32 flags;
260 
261 	/* Status of the request returned from the server side. */
262 	u32 status;
263 
264 	/* Data payload area */
265 	union {
266 		/*
267 		 * Structure used to forward SCSI commands from the
268 		 * client to the server.
269 		 */
270 		struct vmscsi_request vm_srb;
271 
272 		/* Structure used to query channel properties. */
273 		struct vmstorage_channel_properties storage_channel_properties;
274 
275 		/* Used during version negotiations. */
276 		struct vmstorage_protocol_version version;
277 
278 		/* Fibre channel address packet */
279 		struct hv_fc_wwn_packet wwn_packet;
280 
281 		/* Number of sub-channels to create */
282 		u16 sub_channel_count;
283 
284 		/* This will be the maximum of the union members */
285 		u8  buffer[0x34];
286 	};
287 } __packed;
288 
289 /*
290  * Packet Flags:
291  *
292  * This flag indicates that the server should send back a completion for this
293  * packet.
294  */
295 
296 #define REQUEST_COMPLETION_FLAG	0x1
297 
298 /* Matches Windows-end */
299 enum storvsc_request_type {
300 	WRITE_TYPE = 0,
301 	READ_TYPE,
302 	UNKNOWN_TYPE,
303 };
304 
305 /*
306  * SRB status codes and masks. In the 8-bit field, the two high order bits
307  * are flags, while the remaining 6 bits are an integer status code.  The
308  * definitions here include only the subset of the integer status codes that
309  * are tested for in this driver.
310  */
311 #define SRB_STATUS_AUTOSENSE_VALID	0x80
312 #define SRB_STATUS_QUEUE_FROZEN		0x40
313 
314 /* SRB status integer codes */
315 #define SRB_STATUS_SUCCESS		0x01
316 #define SRB_STATUS_ABORTED		0x02
317 #define SRB_STATUS_ERROR		0x04
318 #define SRB_STATUS_INVALID_REQUEST	0x06
319 #define SRB_STATUS_DATA_OVERRUN		0x12
320 #define SRB_STATUS_INVALID_LUN		0x20
321 #define SRB_STATUS_INTERNAL_ERROR	0x30
322 
323 #define SRB_STATUS(status) \
324 	(status & ~(SRB_STATUS_AUTOSENSE_VALID | SRB_STATUS_QUEUE_FROZEN))
325 /*
326  * This is the end of Protocol specific defines.
327  */
328 
329 static int storvsc_ringbuffer_size = (128 * 1024);
330 static u32 max_outstanding_req_per_channel;
331 static int storvsc_change_queue_depth(struct scsi_device *sdev, int queue_depth);
332 
333 static int storvsc_vcpus_per_sub_channel = 4;
334 static unsigned int storvsc_max_hw_queues;
335 
336 module_param(storvsc_ringbuffer_size, int, S_IRUGO);
337 MODULE_PARM_DESC(storvsc_ringbuffer_size, "Ring buffer size (bytes)");
338 
339 module_param(storvsc_max_hw_queues, uint, 0644);
340 MODULE_PARM_DESC(storvsc_max_hw_queues, "Maximum number of hardware queues");
341 
342 module_param(storvsc_vcpus_per_sub_channel, int, S_IRUGO);
343 MODULE_PARM_DESC(storvsc_vcpus_per_sub_channel, "Ratio of VCPUs to subchannels");
344 
345 static int ring_avail_percent_lowater = 10;
346 module_param(ring_avail_percent_lowater, int, S_IRUGO);
347 MODULE_PARM_DESC(ring_avail_percent_lowater,
348 		"Select a channel if available ring size > this in percent");
349 
350 /*
351  * Timeout in seconds for all devices managed by this driver.
352  */
353 static int storvsc_timeout = 180;
354 
355 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
356 static struct scsi_transport_template *fc_transport_template;
357 #endif
358 
359 static struct scsi_host_template scsi_driver;
360 static void storvsc_on_channel_callback(void *context);
361 
362 #define STORVSC_MAX_LUNS_PER_TARGET			255
363 #define STORVSC_MAX_TARGETS				2
364 #define STORVSC_MAX_CHANNELS				8
365 
366 #define STORVSC_FC_MAX_LUNS_PER_TARGET			255
367 #define STORVSC_FC_MAX_TARGETS				128
368 #define STORVSC_FC_MAX_CHANNELS				8
369 
370 #define STORVSC_IDE_MAX_LUNS_PER_TARGET			64
371 #define STORVSC_IDE_MAX_TARGETS				1
372 #define STORVSC_IDE_MAX_CHANNELS			1
373 
374 /*
375  * Upper bound on the size of a storvsc packet.
376  */
377 #define STORVSC_MAX_PKT_SIZE (sizeof(struct vmpacket_descriptor) +\
378 			      sizeof(struct vstor_packet))
379 
380 struct storvsc_cmd_request {
381 	struct scsi_cmnd *cmd;
382 
383 	struct hv_device *device;
384 
385 	/* Synchronize the request/response if needed */
386 	struct completion wait_event;
387 
388 	struct vmbus_channel_packet_multipage_buffer mpb;
389 	struct vmbus_packet_mpb_array *payload;
390 	u32 payload_sz;
391 
392 	struct vstor_packet vstor_packet;
393 };
394 
395 
396 /* A storvsc device is a device object that contains a vmbus channel */
397 struct storvsc_device {
398 	struct hv_device *device;
399 
400 	bool	 destroy;
401 	bool	 drain_notify;
402 	atomic_t num_outstanding_req;
403 	struct Scsi_Host *host;
404 
405 	wait_queue_head_t waiting_to_drain;
406 
407 	/*
408 	 * Each unique Port/Path/Target represents 1 channel ie scsi
409 	 * controller. In reality, the pathid, targetid is always 0
410 	 * and the port is set by us
411 	 */
412 	unsigned int port_number;
413 	unsigned char path_id;
414 	unsigned char target_id;
415 
416 	/*
417 	 * Max I/O, the device can support.
418 	 */
419 	u32   max_transfer_bytes;
420 	/*
421 	 * Number of sub-channels we will open.
422 	 */
423 	u16 num_sc;
424 	struct vmbus_channel **stor_chns;
425 	/*
426 	 * Mask of CPUs bound to subchannels.
427 	 */
428 	struct cpumask alloced_cpus;
429 	/*
430 	 * Serializes modifications of stor_chns[] from storvsc_do_io()
431 	 * and storvsc_change_target_cpu().
432 	 */
433 	spinlock_t lock;
434 	/* Used for vsc/vsp channel reset process */
435 	struct storvsc_cmd_request init_request;
436 	struct storvsc_cmd_request reset_request;
437 	/*
438 	 * Currently active port and node names for FC devices.
439 	 */
440 	u64 node_name;
441 	u64 port_name;
442 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
443 	struct fc_rport *rport;
444 #endif
445 };
446 
447 struct hv_host_device {
448 	struct hv_device *dev;
449 	unsigned int port;
450 	unsigned char path;
451 	unsigned char target;
452 	struct workqueue_struct *handle_error_wq;
453 	struct work_struct host_scan_work;
454 	struct Scsi_Host *host;
455 };
456 
457 struct storvsc_scan_work {
458 	struct work_struct work;
459 	struct Scsi_Host *host;
460 	u8 lun;
461 	u8 tgt_id;
462 };
463 
464 static void storvsc_device_scan(struct work_struct *work)
465 {
466 	struct storvsc_scan_work *wrk;
467 	struct scsi_device *sdev;
468 
469 	wrk = container_of(work, struct storvsc_scan_work, work);
470 
471 	sdev = scsi_device_lookup(wrk->host, 0, wrk->tgt_id, wrk->lun);
472 	if (!sdev)
473 		goto done;
474 	scsi_rescan_device(&sdev->sdev_gendev);
475 	scsi_device_put(sdev);
476 
477 done:
478 	kfree(wrk);
479 }
480 
481 static void storvsc_host_scan(struct work_struct *work)
482 {
483 	struct Scsi_Host *host;
484 	struct scsi_device *sdev;
485 	struct hv_host_device *host_device =
486 		container_of(work, struct hv_host_device, host_scan_work);
487 
488 	host = host_device->host;
489 	/*
490 	 * Before scanning the host, first check to see if any of the
491 	 * currently known devices have been hot removed. We issue a
492 	 * "unit ready" command against all currently known devices.
493 	 * This I/O will result in an error for devices that have been
494 	 * removed. As part of handling the I/O error, we remove the device.
495 	 *
496 	 * When a LUN is added or removed, the host sends us a signal to
497 	 * scan the host. Thus we are forced to discover the LUNs that
498 	 * may have been removed this way.
499 	 */
500 	mutex_lock(&host->scan_mutex);
501 	shost_for_each_device(sdev, host)
502 		scsi_test_unit_ready(sdev, 1, 1, NULL);
503 	mutex_unlock(&host->scan_mutex);
504 	/*
505 	 * Now scan the host to discover LUNs that may have been added.
506 	 */
507 	scsi_scan_host(host);
508 }
509 
510 static void storvsc_remove_lun(struct work_struct *work)
511 {
512 	struct storvsc_scan_work *wrk;
513 	struct scsi_device *sdev;
514 
515 	wrk = container_of(work, struct storvsc_scan_work, work);
516 	if (!scsi_host_get(wrk->host))
517 		goto done;
518 
519 	sdev = scsi_device_lookup(wrk->host, 0, wrk->tgt_id, wrk->lun);
520 
521 	if (sdev) {
522 		scsi_remove_device(sdev);
523 		scsi_device_put(sdev);
524 	}
525 	scsi_host_put(wrk->host);
526 
527 done:
528 	kfree(wrk);
529 }
530 
531 
532 /*
533  * We can get incoming messages from the host that are not in response to
534  * messages that we have sent out. An example of this would be messages
535  * received by the guest to notify dynamic addition/removal of LUNs. To
536  * deal with potential race conditions where the driver may be in the
537  * midst of being unloaded when we might receive an unsolicited message
538  * from the host, we have implemented a mechanism to gurantee sequential
539  * consistency:
540  *
541  * 1) Once the device is marked as being destroyed, we will fail all
542  *    outgoing messages.
543  * 2) We permit incoming messages when the device is being destroyed,
544  *    only to properly account for messages already sent out.
545  */
546 
547 static inline struct storvsc_device *get_out_stor_device(
548 					struct hv_device *device)
549 {
550 	struct storvsc_device *stor_device;
551 
552 	stor_device = hv_get_drvdata(device);
553 
554 	if (stor_device && stor_device->destroy)
555 		stor_device = NULL;
556 
557 	return stor_device;
558 }
559 
560 
561 static inline void storvsc_wait_to_drain(struct storvsc_device *dev)
562 {
563 	dev->drain_notify = true;
564 	wait_event(dev->waiting_to_drain,
565 		   atomic_read(&dev->num_outstanding_req) == 0);
566 	dev->drain_notify = false;
567 }
568 
569 static inline struct storvsc_device *get_in_stor_device(
570 					struct hv_device *device)
571 {
572 	struct storvsc_device *stor_device;
573 
574 	stor_device = hv_get_drvdata(device);
575 
576 	if (!stor_device)
577 		goto get_in_err;
578 
579 	/*
580 	 * If the device is being destroyed; allow incoming
581 	 * traffic only to cleanup outstanding requests.
582 	 */
583 
584 	if (stor_device->destroy  &&
585 		(atomic_read(&stor_device->num_outstanding_req) == 0))
586 		stor_device = NULL;
587 
588 get_in_err:
589 	return stor_device;
590 
591 }
592 
593 static void storvsc_change_target_cpu(struct vmbus_channel *channel, u32 old,
594 				      u32 new)
595 {
596 	struct storvsc_device *stor_device;
597 	struct vmbus_channel *cur_chn;
598 	bool old_is_alloced = false;
599 	struct hv_device *device;
600 	unsigned long flags;
601 	int cpu;
602 
603 	device = channel->primary_channel ?
604 			channel->primary_channel->device_obj
605 				: channel->device_obj;
606 	stor_device = get_out_stor_device(device);
607 	if (!stor_device)
608 		return;
609 
610 	/* See storvsc_do_io() -> get_og_chn(). */
611 	spin_lock_irqsave(&stor_device->lock, flags);
612 
613 	/*
614 	 * Determines if the storvsc device has other channels assigned to
615 	 * the "old" CPU to update the alloced_cpus mask and the stor_chns
616 	 * array.
617 	 */
618 	if (device->channel != channel && device->channel->target_cpu == old) {
619 		cur_chn = device->channel;
620 		old_is_alloced = true;
621 		goto old_is_alloced;
622 	}
623 	list_for_each_entry(cur_chn, &device->channel->sc_list, sc_list) {
624 		if (cur_chn == channel)
625 			continue;
626 		if (cur_chn->target_cpu == old) {
627 			old_is_alloced = true;
628 			goto old_is_alloced;
629 		}
630 	}
631 
632 old_is_alloced:
633 	if (old_is_alloced)
634 		WRITE_ONCE(stor_device->stor_chns[old], cur_chn);
635 	else
636 		cpumask_clear_cpu(old, &stor_device->alloced_cpus);
637 
638 	/* "Flush" the stor_chns array. */
639 	for_each_possible_cpu(cpu) {
640 		if (stor_device->stor_chns[cpu] && !cpumask_test_cpu(
641 					cpu, &stor_device->alloced_cpus))
642 			WRITE_ONCE(stor_device->stor_chns[cpu], NULL);
643 	}
644 
645 	WRITE_ONCE(stor_device->stor_chns[new], channel);
646 	cpumask_set_cpu(new, &stor_device->alloced_cpus);
647 
648 	spin_unlock_irqrestore(&stor_device->lock, flags);
649 }
650 
651 static u64 storvsc_next_request_id(struct vmbus_channel *channel, u64 rqst_addr)
652 {
653 	struct storvsc_cmd_request *request =
654 		(struct storvsc_cmd_request *)(unsigned long)rqst_addr;
655 
656 	if (rqst_addr == VMBUS_RQST_INIT)
657 		return VMBUS_RQST_INIT;
658 	if (rqst_addr == VMBUS_RQST_RESET)
659 		return VMBUS_RQST_RESET;
660 
661 	/*
662 	 * Cannot return an ID of 0, which is reserved for an unsolicited
663 	 * message from Hyper-V.
664 	 */
665 	return (u64)blk_mq_unique_tag(scsi_cmd_to_rq(request->cmd)) + 1;
666 }
667 
668 static void handle_sc_creation(struct vmbus_channel *new_sc)
669 {
670 	struct hv_device *device = new_sc->primary_channel->device_obj;
671 	struct device *dev = &device->device;
672 	struct storvsc_device *stor_device;
673 	struct vmstorage_channel_properties props;
674 	int ret;
675 
676 	stor_device = get_out_stor_device(device);
677 	if (!stor_device)
678 		return;
679 
680 	memset(&props, 0, sizeof(struct vmstorage_channel_properties));
681 	new_sc->max_pkt_size = STORVSC_MAX_PKT_SIZE;
682 
683 	new_sc->next_request_id_callback = storvsc_next_request_id;
684 
685 	ret = vmbus_open(new_sc,
686 			 storvsc_ringbuffer_size,
687 			 storvsc_ringbuffer_size,
688 			 (void *)&props,
689 			 sizeof(struct vmstorage_channel_properties),
690 			 storvsc_on_channel_callback, new_sc);
691 
692 	/* In case vmbus_open() fails, we don't use the sub-channel. */
693 	if (ret != 0) {
694 		dev_err(dev, "Failed to open sub-channel: err=%d\n", ret);
695 		return;
696 	}
697 
698 	new_sc->change_target_cpu_callback = storvsc_change_target_cpu;
699 
700 	/* Add the sub-channel to the array of available channels. */
701 	stor_device->stor_chns[new_sc->target_cpu] = new_sc;
702 	cpumask_set_cpu(new_sc->target_cpu, &stor_device->alloced_cpus);
703 }
704 
705 static void  handle_multichannel_storage(struct hv_device *device, int max_chns)
706 {
707 	struct device *dev = &device->device;
708 	struct storvsc_device *stor_device;
709 	int num_sc;
710 	struct storvsc_cmd_request *request;
711 	struct vstor_packet *vstor_packet;
712 	int ret, t;
713 
714 	/*
715 	 * If the number of CPUs is artificially restricted, such as
716 	 * with maxcpus=1 on the kernel boot line, Hyper-V could offer
717 	 * sub-channels >= the number of CPUs. These sub-channels
718 	 * should not be created. The primary channel is already created
719 	 * and assigned to one CPU, so check against # CPUs - 1.
720 	 */
721 	num_sc = min((int)(num_online_cpus() - 1), max_chns);
722 	if (!num_sc)
723 		return;
724 
725 	stor_device = get_out_stor_device(device);
726 	if (!stor_device)
727 		return;
728 
729 	stor_device->num_sc = num_sc;
730 	request = &stor_device->init_request;
731 	vstor_packet = &request->vstor_packet;
732 
733 	/*
734 	 * Establish a handler for dealing with subchannels.
735 	 */
736 	vmbus_set_sc_create_callback(device->channel, handle_sc_creation);
737 
738 	/*
739 	 * Request the host to create sub-channels.
740 	 */
741 	memset(request, 0, sizeof(struct storvsc_cmd_request));
742 	init_completion(&request->wait_event);
743 	vstor_packet->operation = VSTOR_OPERATION_CREATE_SUB_CHANNELS;
744 	vstor_packet->flags = REQUEST_COMPLETION_FLAG;
745 	vstor_packet->sub_channel_count = num_sc;
746 
747 	ret = vmbus_sendpacket(device->channel, vstor_packet,
748 			       sizeof(struct vstor_packet),
749 			       VMBUS_RQST_INIT,
750 			       VM_PKT_DATA_INBAND,
751 			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
752 
753 	if (ret != 0) {
754 		dev_err(dev, "Failed to create sub-channel: err=%d\n", ret);
755 		return;
756 	}
757 
758 	t = wait_for_completion_timeout(&request->wait_event, 10*HZ);
759 	if (t == 0) {
760 		dev_err(dev, "Failed to create sub-channel: timed out\n");
761 		return;
762 	}
763 
764 	if (vstor_packet->operation != VSTOR_OPERATION_COMPLETE_IO ||
765 	    vstor_packet->status != 0) {
766 		dev_err(dev, "Failed to create sub-channel: op=%d, sts=%d\n",
767 			vstor_packet->operation, vstor_packet->status);
768 		return;
769 	}
770 
771 	/*
772 	 * We need to do nothing here, because vmbus_process_offer()
773 	 * invokes channel->sc_creation_callback, which will open and use
774 	 * the sub-channel(s).
775 	 */
776 }
777 
778 static void cache_wwn(struct storvsc_device *stor_device,
779 		      struct vstor_packet *vstor_packet)
780 {
781 	/*
782 	 * Cache the currently active port and node ww names.
783 	 */
784 	if (vstor_packet->wwn_packet.primary_active) {
785 		stor_device->node_name =
786 			wwn_to_u64(vstor_packet->wwn_packet.primary_node_wwn);
787 		stor_device->port_name =
788 			wwn_to_u64(vstor_packet->wwn_packet.primary_port_wwn);
789 	} else {
790 		stor_device->node_name =
791 			wwn_to_u64(vstor_packet->wwn_packet.secondary_node_wwn);
792 		stor_device->port_name =
793 			wwn_to_u64(vstor_packet->wwn_packet.secondary_port_wwn);
794 	}
795 }
796 
797 
798 static int storvsc_execute_vstor_op(struct hv_device *device,
799 				    struct storvsc_cmd_request *request,
800 				    bool status_check)
801 {
802 	struct storvsc_device *stor_device;
803 	struct vstor_packet *vstor_packet;
804 	int ret, t;
805 
806 	stor_device = get_out_stor_device(device);
807 	if (!stor_device)
808 		return -ENODEV;
809 
810 	vstor_packet = &request->vstor_packet;
811 
812 	init_completion(&request->wait_event);
813 	vstor_packet->flags = REQUEST_COMPLETION_FLAG;
814 
815 	ret = vmbus_sendpacket(device->channel, vstor_packet,
816 			       sizeof(struct vstor_packet),
817 			       VMBUS_RQST_INIT,
818 			       VM_PKT_DATA_INBAND,
819 			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
820 	if (ret != 0)
821 		return ret;
822 
823 	t = wait_for_completion_timeout(&request->wait_event, 5*HZ);
824 	if (t == 0)
825 		return -ETIMEDOUT;
826 
827 	if (!status_check)
828 		return ret;
829 
830 	if (vstor_packet->operation != VSTOR_OPERATION_COMPLETE_IO ||
831 	    vstor_packet->status != 0)
832 		return -EINVAL;
833 
834 	return ret;
835 }
836 
837 static int storvsc_channel_init(struct hv_device *device, bool is_fc)
838 {
839 	struct storvsc_device *stor_device;
840 	struct storvsc_cmd_request *request;
841 	struct vstor_packet *vstor_packet;
842 	int ret, i;
843 	int max_chns;
844 	bool process_sub_channels = false;
845 
846 	stor_device = get_out_stor_device(device);
847 	if (!stor_device)
848 		return -ENODEV;
849 
850 	request = &stor_device->init_request;
851 	vstor_packet = &request->vstor_packet;
852 
853 	/*
854 	 * Now, initiate the vsc/vsp initialization protocol on the open
855 	 * channel
856 	 */
857 	memset(request, 0, sizeof(struct storvsc_cmd_request));
858 	vstor_packet->operation = VSTOR_OPERATION_BEGIN_INITIALIZATION;
859 	ret = storvsc_execute_vstor_op(device, request, true);
860 	if (ret)
861 		return ret;
862 	/*
863 	 * Query host supported protocol version.
864 	 */
865 
866 	for (i = 0; i < ARRAY_SIZE(protocol_version); i++) {
867 		/* reuse the packet for version range supported */
868 		memset(vstor_packet, 0, sizeof(struct vstor_packet));
869 		vstor_packet->operation =
870 			VSTOR_OPERATION_QUERY_PROTOCOL_VERSION;
871 
872 		vstor_packet->version.major_minor = protocol_version[i];
873 
874 		/*
875 		 * The revision number is only used in Windows; set it to 0.
876 		 */
877 		vstor_packet->version.revision = 0;
878 		ret = storvsc_execute_vstor_op(device, request, false);
879 		if (ret != 0)
880 			return ret;
881 
882 		if (vstor_packet->operation != VSTOR_OPERATION_COMPLETE_IO)
883 			return -EINVAL;
884 
885 		if (vstor_packet->status == 0) {
886 			vmstor_proto_version = protocol_version[i];
887 
888 			break;
889 		}
890 	}
891 
892 	if (vstor_packet->status != 0) {
893 		dev_err(&device->device, "Obsolete Hyper-V version\n");
894 		return -EINVAL;
895 	}
896 
897 
898 	memset(vstor_packet, 0, sizeof(struct vstor_packet));
899 	vstor_packet->operation = VSTOR_OPERATION_QUERY_PROPERTIES;
900 	ret = storvsc_execute_vstor_op(device, request, true);
901 	if (ret != 0)
902 		return ret;
903 
904 	/*
905 	 * Check to see if multi-channel support is there.
906 	 * Hosts that implement protocol version of 5.1 and above
907 	 * support multi-channel.
908 	 */
909 	max_chns = vstor_packet->storage_channel_properties.max_channel_cnt;
910 
911 	/*
912 	 * Allocate state to manage the sub-channels.
913 	 * We allocate an array based on the numbers of possible CPUs
914 	 * (Hyper-V does not support cpu online/offline).
915 	 * This Array will be sparseley populated with unique
916 	 * channels - primary + sub-channels.
917 	 * We will however populate all the slots to evenly distribute
918 	 * the load.
919 	 */
920 	stor_device->stor_chns = kcalloc(num_possible_cpus(), sizeof(void *),
921 					 GFP_KERNEL);
922 	if (stor_device->stor_chns == NULL)
923 		return -ENOMEM;
924 
925 	device->channel->change_target_cpu_callback = storvsc_change_target_cpu;
926 
927 	stor_device->stor_chns[device->channel->target_cpu] = device->channel;
928 	cpumask_set_cpu(device->channel->target_cpu,
929 			&stor_device->alloced_cpus);
930 
931 	if (vstor_packet->storage_channel_properties.flags &
932 	    STORAGE_CHANNEL_SUPPORTS_MULTI_CHANNEL)
933 		process_sub_channels = true;
934 
935 	stor_device->max_transfer_bytes =
936 		vstor_packet->storage_channel_properties.max_transfer_bytes;
937 
938 	if (!is_fc)
939 		goto done;
940 
941 	/*
942 	 * For FC devices retrieve FC HBA data.
943 	 */
944 	memset(vstor_packet, 0, sizeof(struct vstor_packet));
945 	vstor_packet->operation = VSTOR_OPERATION_FCHBA_DATA;
946 	ret = storvsc_execute_vstor_op(device, request, true);
947 	if (ret != 0)
948 		return ret;
949 
950 	/*
951 	 * Cache the currently active port and node ww names.
952 	 */
953 	cache_wwn(stor_device, vstor_packet);
954 
955 done:
956 
957 	memset(vstor_packet, 0, sizeof(struct vstor_packet));
958 	vstor_packet->operation = VSTOR_OPERATION_END_INITIALIZATION;
959 	ret = storvsc_execute_vstor_op(device, request, true);
960 	if (ret != 0)
961 		return ret;
962 
963 	if (process_sub_channels)
964 		handle_multichannel_storage(device, max_chns);
965 
966 	return ret;
967 }
968 
969 static void storvsc_handle_error(struct vmscsi_request *vm_srb,
970 				struct scsi_cmnd *scmnd,
971 				struct Scsi_Host *host,
972 				u8 asc, u8 ascq)
973 {
974 	struct storvsc_scan_work *wrk;
975 	void (*process_err_fn)(struct work_struct *work);
976 	struct hv_host_device *host_dev = shost_priv(host);
977 
978 	switch (SRB_STATUS(vm_srb->srb_status)) {
979 	case SRB_STATUS_ERROR:
980 	case SRB_STATUS_ABORTED:
981 	case SRB_STATUS_INVALID_REQUEST:
982 	case SRB_STATUS_INTERNAL_ERROR:
983 		if (vm_srb->srb_status & SRB_STATUS_AUTOSENSE_VALID) {
984 			/* Check for capacity change */
985 			if ((asc == 0x2a) && (ascq == 0x9)) {
986 				process_err_fn = storvsc_device_scan;
987 				/* Retry the I/O that triggered this. */
988 				set_host_byte(scmnd, DID_REQUEUE);
989 				goto do_work;
990 			}
991 
992 			/*
993 			 * Check for "Operating parameters have changed"
994 			 * due to Hyper-V changing the VHD/VHDX BlockSize
995 			 * when adding/removing a differencing disk. This
996 			 * causes discard_granularity to change, so do a
997 			 * rescan to pick up the new granularity. We don't
998 			 * want scsi_report_sense() to output a message
999 			 * that a sysadmin wouldn't know what to do with.
1000 			 */
1001 			if ((asc == 0x3f) && (ascq != 0x03) &&
1002 					(ascq != 0x0e)) {
1003 				process_err_fn = storvsc_device_scan;
1004 				set_host_byte(scmnd, DID_REQUEUE);
1005 				goto do_work;
1006 			}
1007 
1008 			/*
1009 			 * Otherwise, let upper layer deal with the
1010 			 * error when sense message is present
1011 			 */
1012 			return;
1013 		}
1014 
1015 		/*
1016 		 * If there is an error; offline the device since all
1017 		 * error recovery strategies would have already been
1018 		 * deployed on the host side. However, if the command
1019 		 * were a pass-through command deal with it appropriately.
1020 		 */
1021 		switch (scmnd->cmnd[0]) {
1022 		case ATA_16:
1023 		case ATA_12:
1024 			set_host_byte(scmnd, DID_PASSTHROUGH);
1025 			break;
1026 		/*
1027 		 * On some Hyper-V hosts TEST_UNIT_READY command can
1028 		 * return SRB_STATUS_ERROR. Let the upper level code
1029 		 * deal with it based on the sense information.
1030 		 */
1031 		case TEST_UNIT_READY:
1032 			break;
1033 		default:
1034 			set_host_byte(scmnd, DID_ERROR);
1035 		}
1036 		return;
1037 
1038 	case SRB_STATUS_INVALID_LUN:
1039 		set_host_byte(scmnd, DID_NO_CONNECT);
1040 		process_err_fn = storvsc_remove_lun;
1041 		goto do_work;
1042 
1043 	}
1044 	return;
1045 
1046 do_work:
1047 	/*
1048 	 * We need to schedule work to process this error; schedule it.
1049 	 */
1050 	wrk = kmalloc(sizeof(struct storvsc_scan_work), GFP_ATOMIC);
1051 	if (!wrk) {
1052 		set_host_byte(scmnd, DID_BAD_TARGET);
1053 		return;
1054 	}
1055 
1056 	wrk->host = host;
1057 	wrk->lun = vm_srb->lun;
1058 	wrk->tgt_id = vm_srb->target_id;
1059 	INIT_WORK(&wrk->work, process_err_fn);
1060 	queue_work(host_dev->handle_error_wq, &wrk->work);
1061 }
1062 
1063 
1064 static void storvsc_command_completion(struct storvsc_cmd_request *cmd_request,
1065 				       struct storvsc_device *stor_dev)
1066 {
1067 	struct scsi_cmnd *scmnd = cmd_request->cmd;
1068 	struct scsi_sense_hdr sense_hdr;
1069 	struct vmscsi_request *vm_srb;
1070 	u32 data_transfer_length;
1071 	struct Scsi_Host *host;
1072 	u32 payload_sz = cmd_request->payload_sz;
1073 	void *payload = cmd_request->payload;
1074 	bool sense_ok;
1075 
1076 	host = stor_dev->host;
1077 
1078 	vm_srb = &cmd_request->vstor_packet.vm_srb;
1079 	data_transfer_length = vm_srb->data_transfer_length;
1080 
1081 	scmnd->result = vm_srb->scsi_status;
1082 
1083 	if (scmnd->result) {
1084 		sense_ok = scsi_normalize_sense(scmnd->sense_buffer,
1085 				SCSI_SENSE_BUFFERSIZE, &sense_hdr);
1086 
1087 		if (sense_ok && do_logging(STORVSC_LOGGING_WARN))
1088 			scsi_print_sense_hdr(scmnd->device, "storvsc",
1089 					     &sense_hdr);
1090 	}
1091 
1092 	if (vm_srb->srb_status != SRB_STATUS_SUCCESS) {
1093 		storvsc_handle_error(vm_srb, scmnd, host, sense_hdr.asc,
1094 					 sense_hdr.ascq);
1095 		/*
1096 		 * The Windows driver set data_transfer_length on
1097 		 * SRB_STATUS_DATA_OVERRUN. On other errors, this value
1098 		 * is untouched.  In these cases we set it to 0.
1099 		 */
1100 		if (vm_srb->srb_status != SRB_STATUS_DATA_OVERRUN)
1101 			data_transfer_length = 0;
1102 	}
1103 
1104 	/* Validate data_transfer_length (from Hyper-V) */
1105 	if (data_transfer_length > cmd_request->payload->range.len)
1106 		data_transfer_length = cmd_request->payload->range.len;
1107 
1108 	scsi_set_resid(scmnd,
1109 		cmd_request->payload->range.len - data_transfer_length);
1110 
1111 	scsi_done(scmnd);
1112 
1113 	if (payload_sz >
1114 		sizeof(struct vmbus_channel_packet_multipage_buffer))
1115 		kfree(payload);
1116 }
1117 
1118 static void storvsc_on_io_completion(struct storvsc_device *stor_device,
1119 				  struct vstor_packet *vstor_packet,
1120 				  struct storvsc_cmd_request *request)
1121 {
1122 	struct vstor_packet *stor_pkt;
1123 	struct hv_device *device = stor_device->device;
1124 
1125 	stor_pkt = &request->vstor_packet;
1126 
1127 	/*
1128 	 * The current SCSI handling on the host side does
1129 	 * not correctly handle:
1130 	 * INQUIRY command with page code parameter set to 0x80
1131 	 * MODE_SENSE command with cmd[2] == 0x1c
1132 	 *
1133 	 * Setup srb and scsi status so this won't be fatal.
1134 	 * We do this so we can distinguish truly fatal failues
1135 	 * (srb status == 0x4) and off-line the device in that case.
1136 	 */
1137 
1138 	if ((stor_pkt->vm_srb.cdb[0] == INQUIRY) ||
1139 	   (stor_pkt->vm_srb.cdb[0] == MODE_SENSE)) {
1140 		vstor_packet->vm_srb.scsi_status = 0;
1141 		vstor_packet->vm_srb.srb_status = SRB_STATUS_SUCCESS;
1142 	}
1143 
1144 	/* Copy over the status...etc */
1145 	stor_pkt->vm_srb.scsi_status = vstor_packet->vm_srb.scsi_status;
1146 	stor_pkt->vm_srb.srb_status = vstor_packet->vm_srb.srb_status;
1147 
1148 	/*
1149 	 * Copy over the sense_info_length, but limit to the known max
1150 	 * size if Hyper-V returns a bad value.
1151 	 */
1152 	stor_pkt->vm_srb.sense_info_length = min_t(u8, STORVSC_SENSE_BUFFER_SIZE,
1153 		vstor_packet->vm_srb.sense_info_length);
1154 
1155 	if (vstor_packet->vm_srb.scsi_status != 0 ||
1156 	    vstor_packet->vm_srb.srb_status != SRB_STATUS_SUCCESS) {
1157 
1158 		/*
1159 		 * Log TEST_UNIT_READY errors only as warnings. Hyper-V can
1160 		 * return errors when detecting devices using TEST_UNIT_READY,
1161 		 * and logging these as errors produces unhelpful noise.
1162 		 */
1163 		int loglevel = (stor_pkt->vm_srb.cdb[0] == TEST_UNIT_READY) ?
1164 			STORVSC_LOGGING_WARN : STORVSC_LOGGING_ERROR;
1165 
1166 		storvsc_log(device, loglevel,
1167 			"tag#%d cmd 0x%x status: scsi 0x%x srb 0x%x hv 0x%x\n",
1168 			scsi_cmd_to_rq(request->cmd)->tag,
1169 			stor_pkt->vm_srb.cdb[0],
1170 			vstor_packet->vm_srb.scsi_status,
1171 			vstor_packet->vm_srb.srb_status,
1172 			vstor_packet->status);
1173 	}
1174 
1175 	if (vstor_packet->vm_srb.scsi_status == SAM_STAT_CHECK_CONDITION &&
1176 	    (vstor_packet->vm_srb.srb_status & SRB_STATUS_AUTOSENSE_VALID))
1177 		memcpy(request->cmd->sense_buffer,
1178 		       vstor_packet->vm_srb.sense_data,
1179 		       stor_pkt->vm_srb.sense_info_length);
1180 
1181 	stor_pkt->vm_srb.data_transfer_length =
1182 		vstor_packet->vm_srb.data_transfer_length;
1183 
1184 	storvsc_command_completion(request, stor_device);
1185 
1186 	if (atomic_dec_and_test(&stor_device->num_outstanding_req) &&
1187 		stor_device->drain_notify)
1188 		wake_up(&stor_device->waiting_to_drain);
1189 }
1190 
1191 static void storvsc_on_receive(struct storvsc_device *stor_device,
1192 			     struct vstor_packet *vstor_packet,
1193 			     struct storvsc_cmd_request *request)
1194 {
1195 	struct hv_host_device *host_dev;
1196 	switch (vstor_packet->operation) {
1197 	case VSTOR_OPERATION_COMPLETE_IO:
1198 		storvsc_on_io_completion(stor_device, vstor_packet, request);
1199 		break;
1200 
1201 	case VSTOR_OPERATION_REMOVE_DEVICE:
1202 	case VSTOR_OPERATION_ENUMERATE_BUS:
1203 		host_dev = shost_priv(stor_device->host);
1204 		queue_work(
1205 			host_dev->handle_error_wq, &host_dev->host_scan_work);
1206 		break;
1207 
1208 	case VSTOR_OPERATION_FCHBA_DATA:
1209 		cache_wwn(stor_device, vstor_packet);
1210 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
1211 		fc_host_node_name(stor_device->host) = stor_device->node_name;
1212 		fc_host_port_name(stor_device->host) = stor_device->port_name;
1213 #endif
1214 		break;
1215 	default:
1216 		break;
1217 	}
1218 }
1219 
1220 static void storvsc_on_channel_callback(void *context)
1221 {
1222 	struct vmbus_channel *channel = (struct vmbus_channel *)context;
1223 	const struct vmpacket_descriptor *desc;
1224 	struct hv_device *device;
1225 	struct storvsc_device *stor_device;
1226 	struct Scsi_Host *shost;
1227 	unsigned long time_limit = jiffies + msecs_to_jiffies(CALLBACK_TIMEOUT);
1228 
1229 	if (channel->primary_channel != NULL)
1230 		device = channel->primary_channel->device_obj;
1231 	else
1232 		device = channel->device_obj;
1233 
1234 	stor_device = get_in_stor_device(device);
1235 	if (!stor_device)
1236 		return;
1237 
1238 	shost = stor_device->host;
1239 
1240 	foreach_vmbus_pkt(desc, channel) {
1241 		struct vstor_packet *packet = hv_pkt_data(desc);
1242 		struct storvsc_cmd_request *request = NULL;
1243 		u32 pktlen = hv_pkt_datalen(desc);
1244 		u64 rqst_id = desc->trans_id;
1245 		u32 minlen = rqst_id ? sizeof(struct vstor_packet) :
1246 			sizeof(enum vstor_packet_operation);
1247 
1248 		if (unlikely(time_after(jiffies, time_limit))) {
1249 			hv_pkt_iter_close(channel);
1250 			return;
1251 		}
1252 
1253 		if (pktlen < minlen) {
1254 			dev_err(&device->device,
1255 				"Invalid pkt: id=%llu, len=%u, minlen=%u\n",
1256 				rqst_id, pktlen, minlen);
1257 			continue;
1258 		}
1259 
1260 		if (rqst_id == VMBUS_RQST_INIT) {
1261 			request = &stor_device->init_request;
1262 		} else if (rqst_id == VMBUS_RQST_RESET) {
1263 			request = &stor_device->reset_request;
1264 		} else {
1265 			/* Hyper-V can send an unsolicited message with ID of 0 */
1266 			if (rqst_id == 0) {
1267 				/*
1268 				 * storvsc_on_receive() looks at the vstor_packet in the message
1269 				 * from the ring buffer.
1270 				 *
1271 				 * - If the operation in the vstor_packet is COMPLETE_IO, then
1272 				 *   we call storvsc_on_io_completion(), and dereference the
1273 				 *   guest memory address.  Make sure we don't call
1274 				 *   storvsc_on_io_completion() with a guest memory address
1275 				 *   that is zero if Hyper-V were to construct and send such
1276 				 *   a bogus packet.
1277 				 *
1278 				 * - If the operation in the vstor_packet is FCHBA_DATA, then
1279 				 *   we call cache_wwn(), and access the data payload area of
1280 				 *   the packet (wwn_packet); however, there is no guarantee
1281 				 *   that the packet is big enough to contain such area.
1282 				 *   Future-proof the code by rejecting such a bogus packet.
1283 				 */
1284 				if (packet->operation == VSTOR_OPERATION_COMPLETE_IO ||
1285 				    packet->operation == VSTOR_OPERATION_FCHBA_DATA) {
1286 					dev_err(&device->device, "Invalid packet with ID of 0\n");
1287 					continue;
1288 				}
1289 			} else {
1290 				struct scsi_cmnd *scmnd;
1291 
1292 				/* Transaction 'rqst_id' corresponds to tag 'rqst_id - 1' */
1293 				scmnd = scsi_host_find_tag(shost, rqst_id - 1);
1294 				if (scmnd == NULL) {
1295 					dev_err(&device->device, "Incorrect transaction ID\n");
1296 					continue;
1297 				}
1298 				request = (struct storvsc_cmd_request *)scsi_cmd_priv(scmnd);
1299 				scsi_dma_unmap(scmnd);
1300 			}
1301 
1302 			storvsc_on_receive(stor_device, packet, request);
1303 			continue;
1304 		}
1305 
1306 		memcpy(&request->vstor_packet, packet,
1307 		       sizeof(struct vstor_packet));
1308 		complete(&request->wait_event);
1309 	}
1310 }
1311 
1312 static int storvsc_connect_to_vsp(struct hv_device *device, u32 ring_size,
1313 				  bool is_fc)
1314 {
1315 	struct vmstorage_channel_properties props;
1316 	int ret;
1317 
1318 	memset(&props, 0, sizeof(struct vmstorage_channel_properties));
1319 
1320 	device->channel->max_pkt_size = STORVSC_MAX_PKT_SIZE;
1321 	device->channel->next_request_id_callback = storvsc_next_request_id;
1322 
1323 	ret = vmbus_open(device->channel,
1324 			 ring_size,
1325 			 ring_size,
1326 			 (void *)&props,
1327 			 sizeof(struct vmstorage_channel_properties),
1328 			 storvsc_on_channel_callback, device->channel);
1329 
1330 	if (ret != 0)
1331 		return ret;
1332 
1333 	ret = storvsc_channel_init(device, is_fc);
1334 
1335 	return ret;
1336 }
1337 
1338 static int storvsc_dev_remove(struct hv_device *device)
1339 {
1340 	struct storvsc_device *stor_device;
1341 
1342 	stor_device = hv_get_drvdata(device);
1343 
1344 	stor_device->destroy = true;
1345 
1346 	/* Make sure flag is set before waiting */
1347 	wmb();
1348 
1349 	/*
1350 	 * At this point, all outbound traffic should be disable. We
1351 	 * only allow inbound traffic (responses) to proceed so that
1352 	 * outstanding requests can be completed.
1353 	 */
1354 
1355 	storvsc_wait_to_drain(stor_device);
1356 
1357 	/*
1358 	 * Since we have already drained, we don't need to busy wait
1359 	 * as was done in final_release_stor_device()
1360 	 * Note that we cannot set the ext pointer to NULL until
1361 	 * we have drained - to drain the outgoing packets, we need to
1362 	 * allow incoming packets.
1363 	 */
1364 	hv_set_drvdata(device, NULL);
1365 
1366 	/* Close the channel */
1367 	vmbus_close(device->channel);
1368 
1369 	kfree(stor_device->stor_chns);
1370 	kfree(stor_device);
1371 	return 0;
1372 }
1373 
1374 static struct vmbus_channel *get_og_chn(struct storvsc_device *stor_device,
1375 					u16 q_num)
1376 {
1377 	u16 slot = 0;
1378 	u16 hash_qnum;
1379 	const struct cpumask *node_mask;
1380 	int num_channels, tgt_cpu;
1381 
1382 	if (stor_device->num_sc == 0) {
1383 		stor_device->stor_chns[q_num] = stor_device->device->channel;
1384 		return stor_device->device->channel;
1385 	}
1386 
1387 	/*
1388 	 * Our channel array is sparsley populated and we
1389 	 * initiated I/O on a processor/hw-q that does not
1390 	 * currently have a designated channel. Fix this.
1391 	 * The strategy is simple:
1392 	 * I. Ensure NUMA locality
1393 	 * II. Distribute evenly (best effort)
1394 	 */
1395 
1396 	node_mask = cpumask_of_node(cpu_to_node(q_num));
1397 
1398 	num_channels = 0;
1399 	for_each_cpu(tgt_cpu, &stor_device->alloced_cpus) {
1400 		if (cpumask_test_cpu(tgt_cpu, node_mask))
1401 			num_channels++;
1402 	}
1403 	if (num_channels == 0) {
1404 		stor_device->stor_chns[q_num] = stor_device->device->channel;
1405 		return stor_device->device->channel;
1406 	}
1407 
1408 	hash_qnum = q_num;
1409 	while (hash_qnum >= num_channels)
1410 		hash_qnum -= num_channels;
1411 
1412 	for_each_cpu(tgt_cpu, &stor_device->alloced_cpus) {
1413 		if (!cpumask_test_cpu(tgt_cpu, node_mask))
1414 			continue;
1415 		if (slot == hash_qnum)
1416 			break;
1417 		slot++;
1418 	}
1419 
1420 	stor_device->stor_chns[q_num] = stor_device->stor_chns[tgt_cpu];
1421 
1422 	return stor_device->stor_chns[q_num];
1423 }
1424 
1425 
1426 static int storvsc_do_io(struct hv_device *device,
1427 			 struct storvsc_cmd_request *request, u16 q_num)
1428 {
1429 	struct storvsc_device *stor_device;
1430 	struct vstor_packet *vstor_packet;
1431 	struct vmbus_channel *outgoing_channel, *channel;
1432 	unsigned long flags;
1433 	int ret = 0;
1434 	const struct cpumask *node_mask;
1435 	int tgt_cpu;
1436 
1437 	vstor_packet = &request->vstor_packet;
1438 	stor_device = get_out_stor_device(device);
1439 
1440 	if (!stor_device)
1441 		return -ENODEV;
1442 
1443 
1444 	request->device  = device;
1445 	/*
1446 	 * Select an appropriate channel to send the request out.
1447 	 */
1448 	/* See storvsc_change_target_cpu(). */
1449 	outgoing_channel = READ_ONCE(stor_device->stor_chns[q_num]);
1450 	if (outgoing_channel != NULL) {
1451 		if (outgoing_channel->target_cpu == q_num) {
1452 			/*
1453 			 * Ideally, we want to pick a different channel if
1454 			 * available on the same NUMA node.
1455 			 */
1456 			node_mask = cpumask_of_node(cpu_to_node(q_num));
1457 			for_each_cpu_wrap(tgt_cpu,
1458 				 &stor_device->alloced_cpus, q_num + 1) {
1459 				if (!cpumask_test_cpu(tgt_cpu, node_mask))
1460 					continue;
1461 				if (tgt_cpu == q_num)
1462 					continue;
1463 				channel = READ_ONCE(
1464 					stor_device->stor_chns[tgt_cpu]);
1465 				if (channel == NULL)
1466 					continue;
1467 				if (hv_get_avail_to_write_percent(
1468 							&channel->outbound)
1469 						> ring_avail_percent_lowater) {
1470 					outgoing_channel = channel;
1471 					goto found_channel;
1472 				}
1473 			}
1474 
1475 			/*
1476 			 * All the other channels on the same NUMA node are
1477 			 * busy. Try to use the channel on the current CPU
1478 			 */
1479 			if (hv_get_avail_to_write_percent(
1480 						&outgoing_channel->outbound)
1481 					> ring_avail_percent_lowater)
1482 				goto found_channel;
1483 
1484 			/*
1485 			 * If we reach here, all the channels on the current
1486 			 * NUMA node are busy. Try to find a channel in
1487 			 * other NUMA nodes
1488 			 */
1489 			for_each_cpu(tgt_cpu, &stor_device->alloced_cpus) {
1490 				if (cpumask_test_cpu(tgt_cpu, node_mask))
1491 					continue;
1492 				channel = READ_ONCE(
1493 					stor_device->stor_chns[tgt_cpu]);
1494 				if (channel == NULL)
1495 					continue;
1496 				if (hv_get_avail_to_write_percent(
1497 							&channel->outbound)
1498 						> ring_avail_percent_lowater) {
1499 					outgoing_channel = channel;
1500 					goto found_channel;
1501 				}
1502 			}
1503 		}
1504 	} else {
1505 		spin_lock_irqsave(&stor_device->lock, flags);
1506 		outgoing_channel = stor_device->stor_chns[q_num];
1507 		if (outgoing_channel != NULL) {
1508 			spin_unlock_irqrestore(&stor_device->lock, flags);
1509 			goto found_channel;
1510 		}
1511 		outgoing_channel = get_og_chn(stor_device, q_num);
1512 		spin_unlock_irqrestore(&stor_device->lock, flags);
1513 	}
1514 
1515 found_channel:
1516 	vstor_packet->flags |= REQUEST_COMPLETION_FLAG;
1517 
1518 	vstor_packet->vm_srb.length = sizeof(struct vmscsi_request);
1519 
1520 
1521 	vstor_packet->vm_srb.sense_info_length = STORVSC_SENSE_BUFFER_SIZE;
1522 
1523 
1524 	vstor_packet->vm_srb.data_transfer_length =
1525 	request->payload->range.len;
1526 
1527 	vstor_packet->operation = VSTOR_OPERATION_EXECUTE_SRB;
1528 
1529 	if (request->payload->range.len) {
1530 
1531 		ret = vmbus_sendpacket_mpb_desc(outgoing_channel,
1532 				request->payload, request->payload_sz,
1533 				vstor_packet,
1534 				sizeof(struct vstor_packet),
1535 				(unsigned long)request);
1536 	} else {
1537 		ret = vmbus_sendpacket(outgoing_channel, vstor_packet,
1538 			       sizeof(struct vstor_packet),
1539 			       (unsigned long)request,
1540 			       VM_PKT_DATA_INBAND,
1541 			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
1542 	}
1543 
1544 	if (ret != 0)
1545 		return ret;
1546 
1547 	atomic_inc(&stor_device->num_outstanding_req);
1548 
1549 	return ret;
1550 }
1551 
1552 static int storvsc_device_alloc(struct scsi_device *sdevice)
1553 {
1554 	/*
1555 	 * Set blist flag to permit the reading of the VPD pages even when
1556 	 * the target may claim SPC-2 compliance. MSFT targets currently
1557 	 * claim SPC-2 compliance while they implement post SPC-2 features.
1558 	 * With this flag we can correctly handle WRITE_SAME_16 issues.
1559 	 *
1560 	 * Hypervisor reports SCSI_UNKNOWN type for DVD ROM device but
1561 	 * still supports REPORT LUN.
1562 	 */
1563 	sdevice->sdev_bflags = BLIST_REPORTLUN2 | BLIST_TRY_VPD_PAGES;
1564 
1565 	return 0;
1566 }
1567 
1568 static int storvsc_device_configure(struct scsi_device *sdevice)
1569 {
1570 	blk_queue_rq_timeout(sdevice->request_queue, (storvsc_timeout * HZ));
1571 
1572 	/* storvsc devices don't support MAINTENANCE_IN SCSI cmd */
1573 	sdevice->no_report_opcodes = 1;
1574 	sdevice->no_write_same = 1;
1575 
1576 	/*
1577 	 * If the host is WIN8 or WIN8 R2, claim conformance to SPC-3
1578 	 * if the device is a MSFT virtual device.  If the host is
1579 	 * WIN10 or newer, allow write_same.
1580 	 */
1581 	if (!strncmp(sdevice->vendor, "Msft", 4)) {
1582 		switch (vmstor_proto_version) {
1583 		case VMSTOR_PROTO_VERSION_WIN8:
1584 		case VMSTOR_PROTO_VERSION_WIN8_1:
1585 			sdevice->scsi_level = SCSI_SPC_3;
1586 			break;
1587 		}
1588 
1589 		if (vmstor_proto_version >= VMSTOR_PROTO_VERSION_WIN10)
1590 			sdevice->no_write_same = 0;
1591 	}
1592 
1593 	return 0;
1594 }
1595 
1596 static int storvsc_get_chs(struct scsi_device *sdev, struct block_device * bdev,
1597 			   sector_t capacity, int *info)
1598 {
1599 	sector_t nsect = capacity;
1600 	sector_t cylinders = nsect;
1601 	int heads, sectors_pt;
1602 
1603 	/*
1604 	 * We are making up these values; let us keep it simple.
1605 	 */
1606 	heads = 0xff;
1607 	sectors_pt = 0x3f;      /* Sectors per track */
1608 	sector_div(cylinders, heads * sectors_pt);
1609 	if ((sector_t)(cylinders + 1) * heads * sectors_pt < nsect)
1610 		cylinders = 0xffff;
1611 
1612 	info[0] = heads;
1613 	info[1] = sectors_pt;
1614 	info[2] = (int)cylinders;
1615 
1616 	return 0;
1617 }
1618 
1619 static int storvsc_host_reset_handler(struct scsi_cmnd *scmnd)
1620 {
1621 	struct hv_host_device *host_dev = shost_priv(scmnd->device->host);
1622 	struct hv_device *device = host_dev->dev;
1623 
1624 	struct storvsc_device *stor_device;
1625 	struct storvsc_cmd_request *request;
1626 	struct vstor_packet *vstor_packet;
1627 	int ret, t;
1628 
1629 	stor_device = get_out_stor_device(device);
1630 	if (!stor_device)
1631 		return FAILED;
1632 
1633 	request = &stor_device->reset_request;
1634 	vstor_packet = &request->vstor_packet;
1635 	memset(vstor_packet, 0, sizeof(struct vstor_packet));
1636 
1637 	init_completion(&request->wait_event);
1638 
1639 	vstor_packet->operation = VSTOR_OPERATION_RESET_BUS;
1640 	vstor_packet->flags = REQUEST_COMPLETION_FLAG;
1641 	vstor_packet->vm_srb.path_id = stor_device->path_id;
1642 
1643 	ret = vmbus_sendpacket(device->channel, vstor_packet,
1644 			       sizeof(struct vstor_packet),
1645 			       VMBUS_RQST_RESET,
1646 			       VM_PKT_DATA_INBAND,
1647 			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
1648 	if (ret != 0)
1649 		return FAILED;
1650 
1651 	t = wait_for_completion_timeout(&request->wait_event, 5*HZ);
1652 	if (t == 0)
1653 		return TIMEOUT_ERROR;
1654 
1655 
1656 	/*
1657 	 * At this point, all outstanding requests in the adapter
1658 	 * should have been flushed out and return to us
1659 	 * There is a potential race here where the host may be in
1660 	 * the process of responding when we return from here.
1661 	 * Just wait for all in-transit packets to be accounted for
1662 	 * before we return from here.
1663 	 */
1664 	storvsc_wait_to_drain(stor_device);
1665 
1666 	return SUCCESS;
1667 }
1668 
1669 /*
1670  * The host guarantees to respond to each command, although I/O latencies might
1671  * be unbounded on Azure.  Reset the timer unconditionally to give the host a
1672  * chance to perform EH.
1673  */
1674 static enum scsi_timeout_action storvsc_eh_timed_out(struct scsi_cmnd *scmnd)
1675 {
1676 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
1677 	if (scmnd->device->host->transportt == fc_transport_template)
1678 		return fc_eh_timed_out(scmnd);
1679 #endif
1680 	return SCSI_EH_RESET_TIMER;
1681 }
1682 
1683 static bool storvsc_scsi_cmd_ok(struct scsi_cmnd *scmnd)
1684 {
1685 	bool allowed = true;
1686 	u8 scsi_op = scmnd->cmnd[0];
1687 
1688 	switch (scsi_op) {
1689 	/* the host does not handle WRITE_SAME, log accident usage */
1690 	case WRITE_SAME:
1691 	/*
1692 	 * smartd sends this command and the host does not handle
1693 	 * this. So, don't send it.
1694 	 */
1695 	case SET_WINDOW:
1696 		set_host_byte(scmnd, DID_ERROR);
1697 		allowed = false;
1698 		break;
1699 	default:
1700 		break;
1701 	}
1702 	return allowed;
1703 }
1704 
1705 static int storvsc_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *scmnd)
1706 {
1707 	int ret;
1708 	struct hv_host_device *host_dev = shost_priv(host);
1709 	struct hv_device *dev = host_dev->dev;
1710 	struct storvsc_cmd_request *cmd_request = scsi_cmd_priv(scmnd);
1711 	struct scatterlist *sgl;
1712 	struct vmscsi_request *vm_srb;
1713 	struct vmbus_packet_mpb_array  *payload;
1714 	u32 payload_sz;
1715 	u32 length;
1716 
1717 	if (vmstor_proto_version <= VMSTOR_PROTO_VERSION_WIN8) {
1718 		/*
1719 		 * On legacy hosts filter unimplemented commands.
1720 		 * Future hosts are expected to correctly handle
1721 		 * unsupported commands. Furthermore, it is
1722 		 * possible that some of the currently
1723 		 * unsupported commands maybe supported in
1724 		 * future versions of the host.
1725 		 */
1726 		if (!storvsc_scsi_cmd_ok(scmnd)) {
1727 			scsi_done(scmnd);
1728 			return 0;
1729 		}
1730 	}
1731 
1732 	/* Setup the cmd request */
1733 	cmd_request->cmd = scmnd;
1734 
1735 	memset(&cmd_request->vstor_packet, 0, sizeof(struct vstor_packet));
1736 	vm_srb = &cmd_request->vstor_packet.vm_srb;
1737 	vm_srb->time_out_value = 60;
1738 
1739 	vm_srb->srb_flags |=
1740 		SRB_FLAGS_DISABLE_SYNCH_TRANSFER;
1741 
1742 	if (scmnd->device->tagged_supported) {
1743 		vm_srb->srb_flags |=
1744 		(SRB_FLAGS_QUEUE_ACTION_ENABLE | SRB_FLAGS_NO_QUEUE_FREEZE);
1745 		vm_srb->queue_tag = SP_UNTAGGED;
1746 		vm_srb->queue_action = SRB_SIMPLE_TAG_REQUEST;
1747 	}
1748 
1749 	/* Build the SRB */
1750 	switch (scmnd->sc_data_direction) {
1751 	case DMA_TO_DEVICE:
1752 		vm_srb->data_in = WRITE_TYPE;
1753 		vm_srb->srb_flags |= SRB_FLAGS_DATA_OUT;
1754 		break;
1755 	case DMA_FROM_DEVICE:
1756 		vm_srb->data_in = READ_TYPE;
1757 		vm_srb->srb_flags |= SRB_FLAGS_DATA_IN;
1758 		break;
1759 	case DMA_NONE:
1760 		vm_srb->data_in = UNKNOWN_TYPE;
1761 		vm_srb->srb_flags |= SRB_FLAGS_NO_DATA_TRANSFER;
1762 		break;
1763 	default:
1764 		/*
1765 		 * This is DMA_BIDIRECTIONAL or something else we are never
1766 		 * supposed to see here.
1767 		 */
1768 		WARN(1, "Unexpected data direction: %d\n",
1769 		     scmnd->sc_data_direction);
1770 		return -EINVAL;
1771 	}
1772 
1773 
1774 	vm_srb->port_number = host_dev->port;
1775 	vm_srb->path_id = scmnd->device->channel;
1776 	vm_srb->target_id = scmnd->device->id;
1777 	vm_srb->lun = scmnd->device->lun;
1778 
1779 	vm_srb->cdb_length = scmnd->cmd_len;
1780 
1781 	memcpy(vm_srb->cdb, scmnd->cmnd, vm_srb->cdb_length);
1782 
1783 	sgl = (struct scatterlist *)scsi_sglist(scmnd);
1784 
1785 	length = scsi_bufflen(scmnd);
1786 	payload = (struct vmbus_packet_mpb_array *)&cmd_request->mpb;
1787 	payload_sz = 0;
1788 
1789 	if (scsi_sg_count(scmnd)) {
1790 		unsigned long offset_in_hvpg = offset_in_hvpage(sgl->offset);
1791 		unsigned int hvpg_count = HVPFN_UP(offset_in_hvpg + length);
1792 		struct scatterlist *sg;
1793 		unsigned long hvpfn, hvpfns_to_add;
1794 		int j, i = 0, sg_count;
1795 
1796 		payload_sz = (hvpg_count * sizeof(u64) +
1797 			      sizeof(struct vmbus_packet_mpb_array));
1798 
1799 		if (hvpg_count > MAX_PAGE_BUFFER_COUNT) {
1800 			payload = kzalloc(payload_sz, GFP_ATOMIC);
1801 			if (!payload)
1802 				return SCSI_MLQUEUE_DEVICE_BUSY;
1803 		}
1804 
1805 		payload->range.len = length;
1806 		payload->range.offset = offset_in_hvpg;
1807 
1808 		sg_count = scsi_dma_map(scmnd);
1809 		if (sg_count < 0) {
1810 			ret = SCSI_MLQUEUE_DEVICE_BUSY;
1811 			goto err_free_payload;
1812 		}
1813 
1814 		for_each_sg(sgl, sg, sg_count, j) {
1815 			/*
1816 			 * Init values for the current sgl entry. hvpfns_to_add
1817 			 * is in units of Hyper-V size pages. Handling the
1818 			 * PAGE_SIZE != HV_HYP_PAGE_SIZE case also handles
1819 			 * values of sgl->offset that are larger than PAGE_SIZE.
1820 			 * Such offsets are handled even on other than the first
1821 			 * sgl entry, provided they are a multiple of PAGE_SIZE.
1822 			 */
1823 			hvpfn = HVPFN_DOWN(sg_dma_address(sg));
1824 			hvpfns_to_add = HVPFN_UP(sg_dma_address(sg) +
1825 						 sg_dma_len(sg)) - hvpfn;
1826 
1827 			/*
1828 			 * Fill the next portion of the PFN array with
1829 			 * sequential Hyper-V PFNs for the continguous physical
1830 			 * memory described by the sgl entry. The end of the
1831 			 * last sgl should be reached at the same time that
1832 			 * the PFN array is filled.
1833 			 */
1834 			while (hvpfns_to_add--)
1835 				payload->range.pfn_array[i++] = hvpfn++;
1836 		}
1837 	}
1838 
1839 	cmd_request->payload = payload;
1840 	cmd_request->payload_sz = payload_sz;
1841 
1842 	/* Invokes the vsc to start an IO */
1843 	ret = storvsc_do_io(dev, cmd_request, get_cpu());
1844 	put_cpu();
1845 
1846 	if (ret)
1847 		scsi_dma_unmap(scmnd);
1848 
1849 	if (ret == -EAGAIN) {
1850 		/* no more space */
1851 		ret = SCSI_MLQUEUE_DEVICE_BUSY;
1852 		goto err_free_payload;
1853 	}
1854 
1855 	return 0;
1856 
1857 err_free_payload:
1858 	if (payload_sz > sizeof(cmd_request->mpb))
1859 		kfree(payload);
1860 
1861 	return ret;
1862 }
1863 
1864 static struct scsi_host_template scsi_driver = {
1865 	.module	=		THIS_MODULE,
1866 	.name =			"storvsc_host_t",
1867 	.cmd_size =             sizeof(struct storvsc_cmd_request),
1868 	.bios_param =		storvsc_get_chs,
1869 	.queuecommand =		storvsc_queuecommand,
1870 	.eh_host_reset_handler =	storvsc_host_reset_handler,
1871 	.proc_name =		"storvsc_host",
1872 	.eh_timed_out =		storvsc_eh_timed_out,
1873 	.slave_alloc =		storvsc_device_alloc,
1874 	.slave_configure =	storvsc_device_configure,
1875 	.cmd_per_lun =		2048,
1876 	.this_id =		-1,
1877 	/* Ensure there are no gaps in presented sgls */
1878 	.virt_boundary_mask =	HV_HYP_PAGE_SIZE - 1,
1879 	.no_write_same =	1,
1880 	.track_queue_depth =	1,
1881 	.change_queue_depth =	storvsc_change_queue_depth,
1882 };
1883 
1884 enum {
1885 	SCSI_GUID,
1886 	IDE_GUID,
1887 	SFC_GUID,
1888 };
1889 
1890 static const struct hv_vmbus_device_id id_table[] = {
1891 	/* SCSI guid */
1892 	{ HV_SCSI_GUID,
1893 	  .driver_data = SCSI_GUID
1894 	},
1895 	/* IDE guid */
1896 	{ HV_IDE_GUID,
1897 	  .driver_data = IDE_GUID
1898 	},
1899 	/* Fibre Channel GUID */
1900 	{
1901 	  HV_SYNTHFC_GUID,
1902 	  .driver_data = SFC_GUID
1903 	},
1904 	{ },
1905 };
1906 
1907 MODULE_DEVICE_TABLE(vmbus, id_table);
1908 
1909 static const struct { guid_t guid; } fc_guid = { HV_SYNTHFC_GUID };
1910 
1911 static bool hv_dev_is_fc(struct hv_device *hv_dev)
1912 {
1913 	return guid_equal(&fc_guid.guid, &hv_dev->dev_type);
1914 }
1915 
1916 static int storvsc_probe(struct hv_device *device,
1917 			const struct hv_vmbus_device_id *dev_id)
1918 {
1919 	int ret;
1920 	int num_cpus = num_online_cpus();
1921 	int num_present_cpus = num_present_cpus();
1922 	struct Scsi_Host *host;
1923 	struct hv_host_device *host_dev;
1924 	bool dev_is_ide = ((dev_id->driver_data == IDE_GUID) ? true : false);
1925 	bool is_fc = ((dev_id->driver_data == SFC_GUID) ? true : false);
1926 	int target = 0;
1927 	struct storvsc_device *stor_device;
1928 	int max_sub_channels = 0;
1929 	u32 max_xfer_bytes;
1930 
1931 	/*
1932 	 * We support sub-channels for storage on SCSI and FC controllers.
1933 	 * The number of sub-channels offerred is based on the number of
1934 	 * VCPUs in the guest.
1935 	 */
1936 	if (!dev_is_ide)
1937 		max_sub_channels =
1938 			(num_cpus - 1) / storvsc_vcpus_per_sub_channel;
1939 
1940 	scsi_driver.can_queue = max_outstanding_req_per_channel *
1941 				(max_sub_channels + 1) *
1942 				(100 - ring_avail_percent_lowater) / 100;
1943 
1944 	host = scsi_host_alloc(&scsi_driver,
1945 			       sizeof(struct hv_host_device));
1946 	if (!host)
1947 		return -ENOMEM;
1948 
1949 	host_dev = shost_priv(host);
1950 	memset(host_dev, 0, sizeof(struct hv_host_device));
1951 
1952 	host_dev->port = host->host_no;
1953 	host_dev->dev = device;
1954 	host_dev->host = host;
1955 
1956 
1957 	stor_device = kzalloc(sizeof(struct storvsc_device), GFP_KERNEL);
1958 	if (!stor_device) {
1959 		ret = -ENOMEM;
1960 		goto err_out0;
1961 	}
1962 
1963 	stor_device->destroy = false;
1964 	init_waitqueue_head(&stor_device->waiting_to_drain);
1965 	stor_device->device = device;
1966 	stor_device->host = host;
1967 	spin_lock_init(&stor_device->lock);
1968 	hv_set_drvdata(device, stor_device);
1969 	dma_set_min_align_mask(&device->device, HV_HYP_PAGE_SIZE - 1);
1970 
1971 	stor_device->port_number = host->host_no;
1972 	ret = storvsc_connect_to_vsp(device, storvsc_ringbuffer_size, is_fc);
1973 	if (ret)
1974 		goto err_out1;
1975 
1976 	host_dev->path = stor_device->path_id;
1977 	host_dev->target = stor_device->target_id;
1978 
1979 	switch (dev_id->driver_data) {
1980 	case SFC_GUID:
1981 		host->max_lun = STORVSC_FC_MAX_LUNS_PER_TARGET;
1982 		host->max_id = STORVSC_FC_MAX_TARGETS;
1983 		host->max_channel = STORVSC_FC_MAX_CHANNELS - 1;
1984 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
1985 		host->transportt = fc_transport_template;
1986 #endif
1987 		break;
1988 
1989 	case SCSI_GUID:
1990 		host->max_lun = STORVSC_MAX_LUNS_PER_TARGET;
1991 		host->max_id = STORVSC_MAX_TARGETS;
1992 		host->max_channel = STORVSC_MAX_CHANNELS - 1;
1993 		break;
1994 
1995 	default:
1996 		host->max_lun = STORVSC_IDE_MAX_LUNS_PER_TARGET;
1997 		host->max_id = STORVSC_IDE_MAX_TARGETS;
1998 		host->max_channel = STORVSC_IDE_MAX_CHANNELS - 1;
1999 		break;
2000 	}
2001 	/* max cmd length */
2002 	host->max_cmd_len = STORVSC_MAX_CMD_LEN;
2003 	/*
2004 	 * Any reasonable Hyper-V configuration should provide
2005 	 * max_transfer_bytes value aligning to HV_HYP_PAGE_SIZE,
2006 	 * protecting it from any weird value.
2007 	 */
2008 	max_xfer_bytes = round_down(stor_device->max_transfer_bytes, HV_HYP_PAGE_SIZE);
2009 	/* max_hw_sectors_kb */
2010 	host->max_sectors = max_xfer_bytes >> 9;
2011 	/*
2012 	 * There are 2 requirements for Hyper-V storvsc sgl segments,
2013 	 * based on which the below calculation for max segments is
2014 	 * done:
2015 	 *
2016 	 * 1. Except for the first and last sgl segment, all sgl segments
2017 	 *    should be align to HV_HYP_PAGE_SIZE, that also means the
2018 	 *    maximum number of segments in a sgl can be calculated by
2019 	 *    dividing the total max transfer length by HV_HYP_PAGE_SIZE.
2020 	 *
2021 	 * 2. Except for the first and last, each entry in the SGL must
2022 	 *    have an offset that is a multiple of HV_HYP_PAGE_SIZE.
2023 	 */
2024 	host->sg_tablesize = (max_xfer_bytes >> HV_HYP_PAGE_SHIFT) + 1;
2025 	/*
2026 	 * For non-IDE disks, the host supports multiple channels.
2027 	 * Set the number of HW queues we are supporting.
2028 	 */
2029 	if (!dev_is_ide) {
2030 		if (storvsc_max_hw_queues > num_present_cpus) {
2031 			storvsc_max_hw_queues = 0;
2032 			storvsc_log(device, STORVSC_LOGGING_WARN,
2033 				"Resetting invalid storvsc_max_hw_queues value to default.\n");
2034 		}
2035 		if (storvsc_max_hw_queues)
2036 			host->nr_hw_queues = storvsc_max_hw_queues;
2037 		else
2038 			host->nr_hw_queues = num_present_cpus;
2039 	}
2040 
2041 	/*
2042 	 * Set the error handler work queue.
2043 	 */
2044 	host_dev->handle_error_wq =
2045 			alloc_ordered_workqueue("storvsc_error_wq_%d",
2046 						0,
2047 						host->host_no);
2048 	if (!host_dev->handle_error_wq) {
2049 		ret = -ENOMEM;
2050 		goto err_out2;
2051 	}
2052 	INIT_WORK(&host_dev->host_scan_work, storvsc_host_scan);
2053 	/* Register the HBA and start the scsi bus scan */
2054 	ret = scsi_add_host(host, &device->device);
2055 	if (ret != 0)
2056 		goto err_out3;
2057 
2058 	if (!dev_is_ide) {
2059 		scsi_scan_host(host);
2060 	} else {
2061 		target = (device->dev_instance.b[5] << 8 |
2062 			 device->dev_instance.b[4]);
2063 		ret = scsi_add_device(host, 0, target, 0);
2064 		if (ret)
2065 			goto err_out4;
2066 	}
2067 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
2068 	if (host->transportt == fc_transport_template) {
2069 		struct fc_rport_identifiers ids = {
2070 			.roles = FC_PORT_ROLE_FCP_DUMMY_INITIATOR,
2071 		};
2072 
2073 		fc_host_node_name(host) = stor_device->node_name;
2074 		fc_host_port_name(host) = stor_device->port_name;
2075 		stor_device->rport = fc_remote_port_add(host, 0, &ids);
2076 		if (!stor_device->rport) {
2077 			ret = -ENOMEM;
2078 			goto err_out4;
2079 		}
2080 	}
2081 #endif
2082 	return 0;
2083 
2084 err_out4:
2085 	scsi_remove_host(host);
2086 
2087 err_out3:
2088 	destroy_workqueue(host_dev->handle_error_wq);
2089 
2090 err_out2:
2091 	/*
2092 	 * Once we have connected with the host, we would need to
2093 	 * invoke storvsc_dev_remove() to rollback this state and
2094 	 * this call also frees up the stor_device; hence the jump around
2095 	 * err_out1 label.
2096 	 */
2097 	storvsc_dev_remove(device);
2098 	goto err_out0;
2099 
2100 err_out1:
2101 	kfree(stor_device->stor_chns);
2102 	kfree(stor_device);
2103 
2104 err_out0:
2105 	scsi_host_put(host);
2106 	return ret;
2107 }
2108 
2109 /* Change a scsi target's queue depth */
2110 static int storvsc_change_queue_depth(struct scsi_device *sdev, int queue_depth)
2111 {
2112 	if (queue_depth > scsi_driver.can_queue)
2113 		queue_depth = scsi_driver.can_queue;
2114 
2115 	return scsi_change_queue_depth(sdev, queue_depth);
2116 }
2117 
2118 static void storvsc_remove(struct hv_device *dev)
2119 {
2120 	struct storvsc_device *stor_device = hv_get_drvdata(dev);
2121 	struct Scsi_Host *host = stor_device->host;
2122 	struct hv_host_device *host_dev = shost_priv(host);
2123 
2124 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
2125 	if (host->transportt == fc_transport_template) {
2126 		fc_remote_port_delete(stor_device->rport);
2127 		fc_remove_host(host);
2128 	}
2129 #endif
2130 	destroy_workqueue(host_dev->handle_error_wq);
2131 	scsi_remove_host(host);
2132 	storvsc_dev_remove(dev);
2133 	scsi_host_put(host);
2134 }
2135 
2136 static int storvsc_suspend(struct hv_device *hv_dev)
2137 {
2138 	struct storvsc_device *stor_device = hv_get_drvdata(hv_dev);
2139 	struct Scsi_Host *host = stor_device->host;
2140 	struct hv_host_device *host_dev = shost_priv(host);
2141 
2142 	storvsc_wait_to_drain(stor_device);
2143 
2144 	drain_workqueue(host_dev->handle_error_wq);
2145 
2146 	vmbus_close(hv_dev->channel);
2147 
2148 	kfree(stor_device->stor_chns);
2149 	stor_device->stor_chns = NULL;
2150 
2151 	cpumask_clear(&stor_device->alloced_cpus);
2152 
2153 	return 0;
2154 }
2155 
2156 static int storvsc_resume(struct hv_device *hv_dev)
2157 {
2158 	int ret;
2159 
2160 	ret = storvsc_connect_to_vsp(hv_dev, storvsc_ringbuffer_size,
2161 				     hv_dev_is_fc(hv_dev));
2162 	return ret;
2163 }
2164 
2165 static struct hv_driver storvsc_drv = {
2166 	.name = KBUILD_MODNAME,
2167 	.id_table = id_table,
2168 	.probe = storvsc_probe,
2169 	.remove = storvsc_remove,
2170 	.suspend = storvsc_suspend,
2171 	.resume = storvsc_resume,
2172 	.driver = {
2173 		.probe_type = PROBE_PREFER_ASYNCHRONOUS,
2174 	},
2175 };
2176 
2177 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
2178 static struct fc_function_template fc_transport_functions = {
2179 	.show_host_node_name = 1,
2180 	.show_host_port_name = 1,
2181 };
2182 #endif
2183 
2184 static int __init storvsc_drv_init(void)
2185 {
2186 	int ret;
2187 
2188 	/*
2189 	 * Divide the ring buffer data size (which is 1 page less
2190 	 * than the ring buffer size since that page is reserved for
2191 	 * the ring buffer indices) by the max request size (which is
2192 	 * vmbus_channel_packet_multipage_buffer + struct vstor_packet + u64)
2193 	 */
2194 	max_outstanding_req_per_channel =
2195 		((storvsc_ringbuffer_size - PAGE_SIZE) /
2196 		ALIGN(MAX_MULTIPAGE_BUFFER_PACKET +
2197 		sizeof(struct vstor_packet) + sizeof(u64),
2198 		sizeof(u64)));
2199 
2200 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
2201 	fc_transport_template = fc_attach_transport(&fc_transport_functions);
2202 	if (!fc_transport_template)
2203 		return -ENODEV;
2204 #endif
2205 
2206 	ret = vmbus_driver_register(&storvsc_drv);
2207 
2208 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
2209 	if (ret)
2210 		fc_release_transport(fc_transport_template);
2211 #endif
2212 
2213 	return ret;
2214 }
2215 
2216 static void __exit storvsc_drv_exit(void)
2217 {
2218 	vmbus_driver_unregister(&storvsc_drv);
2219 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
2220 	fc_release_transport(fc_transport_template);
2221 #endif
2222 }
2223 
2224 MODULE_LICENSE("GPL");
2225 MODULE_DESCRIPTION("Microsoft Hyper-V virtual storage driver");
2226 module_init(storvsc_drv_init);
2227 module_exit(storvsc_drv_exit);
2228