xref: /openbmc/linux/drivers/scsi/storvsc_drv.c (revision 83146efc)
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_TIMEOUT		0x09
320 #define SRB_STATUS_SELECTION_TIMEOUT	0x0A
321 #define SRB_STATUS_BUS_RESET		0x0E
322 #define SRB_STATUS_DATA_OVERRUN		0x12
323 #define SRB_STATUS_INVALID_LUN		0x20
324 #define SRB_STATUS_INTERNAL_ERROR	0x30
325 
326 #define SRB_STATUS(status) \
327 	(status & ~(SRB_STATUS_AUTOSENSE_VALID | SRB_STATUS_QUEUE_FROZEN))
328 /*
329  * This is the end of Protocol specific defines.
330  */
331 
332 static int storvsc_ringbuffer_size = (128 * 1024);
333 static u32 max_outstanding_req_per_channel;
334 static int storvsc_change_queue_depth(struct scsi_device *sdev, int queue_depth);
335 
336 static int storvsc_vcpus_per_sub_channel = 4;
337 static unsigned int storvsc_max_hw_queues;
338 
339 module_param(storvsc_ringbuffer_size, int, S_IRUGO);
340 MODULE_PARM_DESC(storvsc_ringbuffer_size, "Ring buffer size (bytes)");
341 
342 module_param(storvsc_max_hw_queues, uint, 0644);
343 MODULE_PARM_DESC(storvsc_max_hw_queues, "Maximum number of hardware queues");
344 
345 module_param(storvsc_vcpus_per_sub_channel, int, S_IRUGO);
346 MODULE_PARM_DESC(storvsc_vcpus_per_sub_channel, "Ratio of VCPUs to subchannels");
347 
348 static int ring_avail_percent_lowater = 10;
349 module_param(ring_avail_percent_lowater, int, S_IRUGO);
350 MODULE_PARM_DESC(ring_avail_percent_lowater,
351 		"Select a channel if available ring size > this in percent");
352 
353 /*
354  * Timeout in seconds for all devices managed by this driver.
355  */
356 static int storvsc_timeout = 180;
357 
358 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
359 static struct scsi_transport_template *fc_transport_template;
360 #endif
361 
362 static struct scsi_host_template scsi_driver;
363 static void storvsc_on_channel_callback(void *context);
364 
365 #define STORVSC_MAX_LUNS_PER_TARGET			255
366 #define STORVSC_MAX_TARGETS				2
367 #define STORVSC_MAX_CHANNELS				8
368 
369 #define STORVSC_FC_MAX_LUNS_PER_TARGET			255
370 #define STORVSC_FC_MAX_TARGETS				128
371 #define STORVSC_FC_MAX_CHANNELS				8
372 #define STORVSC_FC_MAX_XFER_SIZE			((u32)(512 * 1024))
373 
374 #define STORVSC_IDE_MAX_LUNS_PER_TARGET			64
375 #define STORVSC_IDE_MAX_TARGETS				1
376 #define STORVSC_IDE_MAX_CHANNELS			1
377 
378 /*
379  * Upper bound on the size of a storvsc packet.
380  */
381 #define STORVSC_MAX_PKT_SIZE (sizeof(struct vmpacket_descriptor) +\
382 			      sizeof(struct vstor_packet))
383 
384 struct storvsc_cmd_request {
385 	struct scsi_cmnd *cmd;
386 
387 	struct hv_device *device;
388 
389 	/* Synchronize the request/response if needed */
390 	struct completion wait_event;
391 
392 	struct vmbus_channel_packet_multipage_buffer mpb;
393 	struct vmbus_packet_mpb_array *payload;
394 	u32 payload_sz;
395 
396 	struct vstor_packet vstor_packet;
397 };
398 
399 
400 /* A storvsc device is a device object that contains a vmbus channel */
401 struct storvsc_device {
402 	struct hv_device *device;
403 
404 	bool	 destroy;
405 	bool	 drain_notify;
406 	atomic_t num_outstanding_req;
407 	struct Scsi_Host *host;
408 
409 	wait_queue_head_t waiting_to_drain;
410 
411 	/*
412 	 * Each unique Port/Path/Target represents 1 channel ie scsi
413 	 * controller. In reality, the pathid, targetid is always 0
414 	 * and the port is set by us
415 	 */
416 	unsigned int port_number;
417 	unsigned char path_id;
418 	unsigned char target_id;
419 
420 	/*
421 	 * Max I/O, the device can support.
422 	 */
423 	u32   max_transfer_bytes;
424 	/*
425 	 * Number of sub-channels we will open.
426 	 */
427 	u16 num_sc;
428 	struct vmbus_channel **stor_chns;
429 	/*
430 	 * Mask of CPUs bound to subchannels.
431 	 */
432 	struct cpumask alloced_cpus;
433 	/*
434 	 * Serializes modifications of stor_chns[] from storvsc_do_io()
435 	 * and storvsc_change_target_cpu().
436 	 */
437 	spinlock_t lock;
438 	/* Used for vsc/vsp channel reset process */
439 	struct storvsc_cmd_request init_request;
440 	struct storvsc_cmd_request reset_request;
441 	/*
442 	 * Currently active port and node names for FC devices.
443 	 */
444 	u64 node_name;
445 	u64 port_name;
446 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
447 	struct fc_rport *rport;
448 #endif
449 };
450 
451 struct hv_host_device {
452 	struct hv_device *dev;
453 	unsigned int port;
454 	unsigned char path;
455 	unsigned char target;
456 	struct workqueue_struct *handle_error_wq;
457 	struct work_struct host_scan_work;
458 	struct Scsi_Host *host;
459 };
460 
461 struct storvsc_scan_work {
462 	struct work_struct work;
463 	struct Scsi_Host *host;
464 	u8 lun;
465 	u8 tgt_id;
466 };
467 
468 static void storvsc_device_scan(struct work_struct *work)
469 {
470 	struct storvsc_scan_work *wrk;
471 	struct scsi_device *sdev;
472 
473 	wrk = container_of(work, struct storvsc_scan_work, work);
474 
475 	sdev = scsi_device_lookup(wrk->host, 0, wrk->tgt_id, wrk->lun);
476 	if (!sdev)
477 		goto done;
478 	scsi_rescan_device(sdev);
479 	scsi_device_put(sdev);
480 
481 done:
482 	kfree(wrk);
483 }
484 
485 static void storvsc_host_scan(struct work_struct *work)
486 {
487 	struct Scsi_Host *host;
488 	struct scsi_device *sdev;
489 	struct hv_host_device *host_device =
490 		container_of(work, struct hv_host_device, host_scan_work);
491 
492 	host = host_device->host;
493 	/*
494 	 * Before scanning the host, first check to see if any of the
495 	 * currently known devices have been hot removed. We issue a
496 	 * "unit ready" command against all currently known devices.
497 	 * This I/O will result in an error for devices that have been
498 	 * removed. As part of handling the I/O error, we remove the device.
499 	 *
500 	 * When a LUN is added or removed, the host sends us a signal to
501 	 * scan the host. Thus we are forced to discover the LUNs that
502 	 * may have been removed this way.
503 	 */
504 	mutex_lock(&host->scan_mutex);
505 	shost_for_each_device(sdev, host)
506 		scsi_test_unit_ready(sdev, 1, 1, NULL);
507 	mutex_unlock(&host->scan_mutex);
508 	/*
509 	 * Now scan the host to discover LUNs that may have been added.
510 	 */
511 	scsi_scan_host(host);
512 }
513 
514 static void storvsc_remove_lun(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 	if (!scsi_host_get(wrk->host))
521 		goto done;
522 
523 	sdev = scsi_device_lookup(wrk->host, 0, wrk->tgt_id, wrk->lun);
524 
525 	if (sdev) {
526 		scsi_remove_device(sdev);
527 		scsi_device_put(sdev);
528 	}
529 	scsi_host_put(wrk->host);
530 
531 done:
532 	kfree(wrk);
533 }
534 
535 
536 /*
537  * We can get incoming messages from the host that are not in response to
538  * messages that we have sent out. An example of this would be messages
539  * received by the guest to notify dynamic addition/removal of LUNs. To
540  * deal with potential race conditions where the driver may be in the
541  * midst of being unloaded when we might receive an unsolicited message
542  * from the host, we have implemented a mechanism to gurantee sequential
543  * consistency:
544  *
545  * 1) Once the device is marked as being destroyed, we will fail all
546  *    outgoing messages.
547  * 2) We permit incoming messages when the device is being destroyed,
548  *    only to properly account for messages already sent out.
549  */
550 
551 static inline struct storvsc_device *get_out_stor_device(
552 					struct hv_device *device)
553 {
554 	struct storvsc_device *stor_device;
555 
556 	stor_device = hv_get_drvdata(device);
557 
558 	if (stor_device && stor_device->destroy)
559 		stor_device = NULL;
560 
561 	return stor_device;
562 }
563 
564 
565 static inline void storvsc_wait_to_drain(struct storvsc_device *dev)
566 {
567 	dev->drain_notify = true;
568 	wait_event(dev->waiting_to_drain,
569 		   atomic_read(&dev->num_outstanding_req) == 0);
570 	dev->drain_notify = false;
571 }
572 
573 static inline struct storvsc_device *get_in_stor_device(
574 					struct hv_device *device)
575 {
576 	struct storvsc_device *stor_device;
577 
578 	stor_device = hv_get_drvdata(device);
579 
580 	if (!stor_device)
581 		goto get_in_err;
582 
583 	/*
584 	 * If the device is being destroyed; allow incoming
585 	 * traffic only to cleanup outstanding requests.
586 	 */
587 
588 	if (stor_device->destroy  &&
589 		(atomic_read(&stor_device->num_outstanding_req) == 0))
590 		stor_device = NULL;
591 
592 get_in_err:
593 	return stor_device;
594 
595 }
596 
597 static void storvsc_change_target_cpu(struct vmbus_channel *channel, u32 old,
598 				      u32 new)
599 {
600 	struct storvsc_device *stor_device;
601 	struct vmbus_channel *cur_chn;
602 	bool old_is_alloced = false;
603 	struct hv_device *device;
604 	unsigned long flags;
605 	int cpu;
606 
607 	device = channel->primary_channel ?
608 			channel->primary_channel->device_obj
609 				: channel->device_obj;
610 	stor_device = get_out_stor_device(device);
611 	if (!stor_device)
612 		return;
613 
614 	/* See storvsc_do_io() -> get_og_chn(). */
615 	spin_lock_irqsave(&stor_device->lock, flags);
616 
617 	/*
618 	 * Determines if the storvsc device has other channels assigned to
619 	 * the "old" CPU to update the alloced_cpus mask and the stor_chns
620 	 * array.
621 	 */
622 	if (device->channel != channel && device->channel->target_cpu == old) {
623 		cur_chn = device->channel;
624 		old_is_alloced = true;
625 		goto old_is_alloced;
626 	}
627 	list_for_each_entry(cur_chn, &device->channel->sc_list, sc_list) {
628 		if (cur_chn == channel)
629 			continue;
630 		if (cur_chn->target_cpu == old) {
631 			old_is_alloced = true;
632 			goto old_is_alloced;
633 		}
634 	}
635 
636 old_is_alloced:
637 	if (old_is_alloced)
638 		WRITE_ONCE(stor_device->stor_chns[old], cur_chn);
639 	else
640 		cpumask_clear_cpu(old, &stor_device->alloced_cpus);
641 
642 	/* "Flush" the stor_chns array. */
643 	for_each_possible_cpu(cpu) {
644 		if (stor_device->stor_chns[cpu] && !cpumask_test_cpu(
645 					cpu, &stor_device->alloced_cpus))
646 			WRITE_ONCE(stor_device->stor_chns[cpu], NULL);
647 	}
648 
649 	WRITE_ONCE(stor_device->stor_chns[new], channel);
650 	cpumask_set_cpu(new, &stor_device->alloced_cpus);
651 
652 	spin_unlock_irqrestore(&stor_device->lock, flags);
653 }
654 
655 static u64 storvsc_next_request_id(struct vmbus_channel *channel, u64 rqst_addr)
656 {
657 	struct storvsc_cmd_request *request =
658 		(struct storvsc_cmd_request *)(unsigned long)rqst_addr;
659 
660 	if (rqst_addr == VMBUS_RQST_INIT)
661 		return VMBUS_RQST_INIT;
662 	if (rqst_addr == VMBUS_RQST_RESET)
663 		return VMBUS_RQST_RESET;
664 
665 	/*
666 	 * Cannot return an ID of 0, which is reserved for an unsolicited
667 	 * message from Hyper-V.
668 	 */
669 	return (u64)blk_mq_unique_tag(scsi_cmd_to_rq(request->cmd)) + 1;
670 }
671 
672 static void handle_sc_creation(struct vmbus_channel *new_sc)
673 {
674 	struct hv_device *device = new_sc->primary_channel->device_obj;
675 	struct device *dev = &device->device;
676 	struct storvsc_device *stor_device;
677 	struct vmstorage_channel_properties props;
678 	int ret;
679 
680 	stor_device = get_out_stor_device(device);
681 	if (!stor_device)
682 		return;
683 
684 	memset(&props, 0, sizeof(struct vmstorage_channel_properties));
685 	new_sc->max_pkt_size = STORVSC_MAX_PKT_SIZE;
686 
687 	new_sc->next_request_id_callback = storvsc_next_request_id;
688 
689 	ret = vmbus_open(new_sc,
690 			 storvsc_ringbuffer_size,
691 			 storvsc_ringbuffer_size,
692 			 (void *)&props,
693 			 sizeof(struct vmstorage_channel_properties),
694 			 storvsc_on_channel_callback, new_sc);
695 
696 	/* In case vmbus_open() fails, we don't use the sub-channel. */
697 	if (ret != 0) {
698 		dev_err(dev, "Failed to open sub-channel: err=%d\n", ret);
699 		return;
700 	}
701 
702 	new_sc->change_target_cpu_callback = storvsc_change_target_cpu;
703 
704 	/* Add the sub-channel to the array of available channels. */
705 	stor_device->stor_chns[new_sc->target_cpu] = new_sc;
706 	cpumask_set_cpu(new_sc->target_cpu, &stor_device->alloced_cpus);
707 }
708 
709 static void  handle_multichannel_storage(struct hv_device *device, int max_chns)
710 {
711 	struct device *dev = &device->device;
712 	struct storvsc_device *stor_device;
713 	int num_sc;
714 	struct storvsc_cmd_request *request;
715 	struct vstor_packet *vstor_packet;
716 	int ret, t;
717 
718 	/*
719 	 * If the number of CPUs is artificially restricted, such as
720 	 * with maxcpus=1 on the kernel boot line, Hyper-V could offer
721 	 * sub-channels >= the number of CPUs. These sub-channels
722 	 * should not be created. The primary channel is already created
723 	 * and assigned to one CPU, so check against # CPUs - 1.
724 	 */
725 	num_sc = min((int)(num_online_cpus() - 1), max_chns);
726 	if (!num_sc)
727 		return;
728 
729 	stor_device = get_out_stor_device(device);
730 	if (!stor_device)
731 		return;
732 
733 	stor_device->num_sc = num_sc;
734 	request = &stor_device->init_request;
735 	vstor_packet = &request->vstor_packet;
736 
737 	/*
738 	 * Establish a handler for dealing with subchannels.
739 	 */
740 	vmbus_set_sc_create_callback(device->channel, handle_sc_creation);
741 
742 	/*
743 	 * Request the host to create sub-channels.
744 	 */
745 	memset(request, 0, sizeof(struct storvsc_cmd_request));
746 	init_completion(&request->wait_event);
747 	vstor_packet->operation = VSTOR_OPERATION_CREATE_SUB_CHANNELS;
748 	vstor_packet->flags = REQUEST_COMPLETION_FLAG;
749 	vstor_packet->sub_channel_count = num_sc;
750 
751 	ret = vmbus_sendpacket(device->channel, vstor_packet,
752 			       sizeof(struct vstor_packet),
753 			       VMBUS_RQST_INIT,
754 			       VM_PKT_DATA_INBAND,
755 			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
756 
757 	if (ret != 0) {
758 		dev_err(dev, "Failed to create sub-channel: err=%d\n", ret);
759 		return;
760 	}
761 
762 	t = wait_for_completion_timeout(&request->wait_event, 10*HZ);
763 	if (t == 0) {
764 		dev_err(dev, "Failed to create sub-channel: timed out\n");
765 		return;
766 	}
767 
768 	if (vstor_packet->operation != VSTOR_OPERATION_COMPLETE_IO ||
769 	    vstor_packet->status != 0) {
770 		dev_err(dev, "Failed to create sub-channel: op=%d, sts=%d\n",
771 			vstor_packet->operation, vstor_packet->status);
772 		return;
773 	}
774 
775 	/*
776 	 * We need to do nothing here, because vmbus_process_offer()
777 	 * invokes channel->sc_creation_callback, which will open and use
778 	 * the sub-channel(s).
779 	 */
780 }
781 
782 static void cache_wwn(struct storvsc_device *stor_device,
783 		      struct vstor_packet *vstor_packet)
784 {
785 	/*
786 	 * Cache the currently active port and node ww names.
787 	 */
788 	if (vstor_packet->wwn_packet.primary_active) {
789 		stor_device->node_name =
790 			wwn_to_u64(vstor_packet->wwn_packet.primary_node_wwn);
791 		stor_device->port_name =
792 			wwn_to_u64(vstor_packet->wwn_packet.primary_port_wwn);
793 	} else {
794 		stor_device->node_name =
795 			wwn_to_u64(vstor_packet->wwn_packet.secondary_node_wwn);
796 		stor_device->port_name =
797 			wwn_to_u64(vstor_packet->wwn_packet.secondary_port_wwn);
798 	}
799 }
800 
801 
802 static int storvsc_execute_vstor_op(struct hv_device *device,
803 				    struct storvsc_cmd_request *request,
804 				    bool status_check)
805 {
806 	struct storvsc_device *stor_device;
807 	struct vstor_packet *vstor_packet;
808 	int ret, t;
809 
810 	stor_device = get_out_stor_device(device);
811 	if (!stor_device)
812 		return -ENODEV;
813 
814 	vstor_packet = &request->vstor_packet;
815 
816 	init_completion(&request->wait_event);
817 	vstor_packet->flags = REQUEST_COMPLETION_FLAG;
818 
819 	ret = vmbus_sendpacket(device->channel, vstor_packet,
820 			       sizeof(struct vstor_packet),
821 			       VMBUS_RQST_INIT,
822 			       VM_PKT_DATA_INBAND,
823 			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
824 	if (ret != 0)
825 		return ret;
826 
827 	t = wait_for_completion_timeout(&request->wait_event, 5*HZ);
828 	if (t == 0)
829 		return -ETIMEDOUT;
830 
831 	if (!status_check)
832 		return ret;
833 
834 	if (vstor_packet->operation != VSTOR_OPERATION_COMPLETE_IO ||
835 	    vstor_packet->status != 0)
836 		return -EINVAL;
837 
838 	return ret;
839 }
840 
841 static int storvsc_channel_init(struct hv_device *device, bool is_fc)
842 {
843 	struct storvsc_device *stor_device;
844 	struct storvsc_cmd_request *request;
845 	struct vstor_packet *vstor_packet;
846 	int ret, i;
847 	int max_chns;
848 	bool process_sub_channels = false;
849 
850 	stor_device = get_out_stor_device(device);
851 	if (!stor_device)
852 		return -ENODEV;
853 
854 	request = &stor_device->init_request;
855 	vstor_packet = &request->vstor_packet;
856 
857 	/*
858 	 * Now, initiate the vsc/vsp initialization protocol on the open
859 	 * channel
860 	 */
861 	memset(request, 0, sizeof(struct storvsc_cmd_request));
862 	vstor_packet->operation = VSTOR_OPERATION_BEGIN_INITIALIZATION;
863 	ret = storvsc_execute_vstor_op(device, request, true);
864 	if (ret)
865 		return ret;
866 	/*
867 	 * Query host supported protocol version.
868 	 */
869 
870 	for (i = 0; i < ARRAY_SIZE(protocol_version); i++) {
871 		/* reuse the packet for version range supported */
872 		memset(vstor_packet, 0, sizeof(struct vstor_packet));
873 		vstor_packet->operation =
874 			VSTOR_OPERATION_QUERY_PROTOCOL_VERSION;
875 
876 		vstor_packet->version.major_minor = protocol_version[i];
877 
878 		/*
879 		 * The revision number is only used in Windows; set it to 0.
880 		 */
881 		vstor_packet->version.revision = 0;
882 		ret = storvsc_execute_vstor_op(device, request, false);
883 		if (ret != 0)
884 			return ret;
885 
886 		if (vstor_packet->operation != VSTOR_OPERATION_COMPLETE_IO)
887 			return -EINVAL;
888 
889 		if (vstor_packet->status == 0) {
890 			vmstor_proto_version = protocol_version[i];
891 
892 			break;
893 		}
894 	}
895 
896 	if (vstor_packet->status != 0) {
897 		dev_err(&device->device, "Obsolete Hyper-V version\n");
898 		return -EINVAL;
899 	}
900 
901 
902 	memset(vstor_packet, 0, sizeof(struct vstor_packet));
903 	vstor_packet->operation = VSTOR_OPERATION_QUERY_PROPERTIES;
904 	ret = storvsc_execute_vstor_op(device, request, true);
905 	if (ret != 0)
906 		return ret;
907 
908 	/*
909 	 * Check to see if multi-channel support is there.
910 	 * Hosts that implement protocol version of 5.1 and above
911 	 * support multi-channel.
912 	 */
913 	max_chns = vstor_packet->storage_channel_properties.max_channel_cnt;
914 
915 	/*
916 	 * Allocate state to manage the sub-channels.
917 	 * We allocate an array based on the numbers of possible CPUs
918 	 * (Hyper-V does not support cpu online/offline).
919 	 * This Array will be sparseley populated with unique
920 	 * channels - primary + sub-channels.
921 	 * We will however populate all the slots to evenly distribute
922 	 * the load.
923 	 */
924 	stor_device->stor_chns = kcalloc(num_possible_cpus(), sizeof(void *),
925 					 GFP_KERNEL);
926 	if (stor_device->stor_chns == NULL)
927 		return -ENOMEM;
928 
929 	device->channel->change_target_cpu_callback = storvsc_change_target_cpu;
930 
931 	stor_device->stor_chns[device->channel->target_cpu] = device->channel;
932 	cpumask_set_cpu(device->channel->target_cpu,
933 			&stor_device->alloced_cpus);
934 
935 	if (vstor_packet->storage_channel_properties.flags &
936 	    STORAGE_CHANNEL_SUPPORTS_MULTI_CHANNEL)
937 		process_sub_channels = true;
938 
939 	stor_device->max_transfer_bytes =
940 		vstor_packet->storage_channel_properties.max_transfer_bytes;
941 
942 	if (!is_fc)
943 		goto done;
944 
945 	/*
946 	 * For FC devices retrieve FC HBA data.
947 	 */
948 	memset(vstor_packet, 0, sizeof(struct vstor_packet));
949 	vstor_packet->operation = VSTOR_OPERATION_FCHBA_DATA;
950 	ret = storvsc_execute_vstor_op(device, request, true);
951 	if (ret != 0)
952 		return ret;
953 
954 	/*
955 	 * Cache the currently active port and node ww names.
956 	 */
957 	cache_wwn(stor_device, vstor_packet);
958 
959 done:
960 
961 	memset(vstor_packet, 0, sizeof(struct vstor_packet));
962 	vstor_packet->operation = VSTOR_OPERATION_END_INITIALIZATION;
963 	ret = storvsc_execute_vstor_op(device, request, true);
964 	if (ret != 0)
965 		return ret;
966 
967 	if (process_sub_channels)
968 		handle_multichannel_storage(device, max_chns);
969 
970 	return ret;
971 }
972 
973 static void storvsc_handle_error(struct vmscsi_request *vm_srb,
974 				struct scsi_cmnd *scmnd,
975 				struct Scsi_Host *host,
976 				u8 asc, u8 ascq)
977 {
978 	struct storvsc_scan_work *wrk;
979 	void (*process_err_fn)(struct work_struct *work);
980 	struct hv_host_device *host_dev = shost_priv(host);
981 
982 	switch (SRB_STATUS(vm_srb->srb_status)) {
983 	case SRB_STATUS_ERROR:
984 	case SRB_STATUS_ABORTED:
985 	case SRB_STATUS_INVALID_REQUEST:
986 	case SRB_STATUS_INTERNAL_ERROR:
987 	case SRB_STATUS_TIMEOUT:
988 	case SRB_STATUS_SELECTION_TIMEOUT:
989 	case SRB_STATUS_BUS_RESET:
990 	case SRB_STATUS_DATA_OVERRUN:
991 		if (vm_srb->srb_status & SRB_STATUS_AUTOSENSE_VALID) {
992 			/* Check for capacity change */
993 			if ((asc == 0x2a) && (ascq == 0x9)) {
994 				process_err_fn = storvsc_device_scan;
995 				/* Retry the I/O that triggered this. */
996 				set_host_byte(scmnd, DID_REQUEUE);
997 				goto do_work;
998 			}
999 
1000 			/*
1001 			 * Check for "Operating parameters have changed"
1002 			 * due to Hyper-V changing the VHD/VHDX BlockSize
1003 			 * when adding/removing a differencing disk. This
1004 			 * causes discard_granularity to change, so do a
1005 			 * rescan to pick up the new granularity. We don't
1006 			 * want scsi_report_sense() to output a message
1007 			 * that a sysadmin wouldn't know what to do with.
1008 			 */
1009 			if ((asc == 0x3f) && (ascq != 0x03) &&
1010 					(ascq != 0x0e)) {
1011 				process_err_fn = storvsc_device_scan;
1012 				set_host_byte(scmnd, DID_REQUEUE);
1013 				goto do_work;
1014 			}
1015 
1016 			/*
1017 			 * Otherwise, let upper layer deal with the
1018 			 * error when sense message is present
1019 			 */
1020 			return;
1021 		}
1022 
1023 		/*
1024 		 * If there is an error; offline the device since all
1025 		 * error recovery strategies would have already been
1026 		 * deployed on the host side. However, if the command
1027 		 * were a pass-through command deal with it appropriately.
1028 		 */
1029 		switch (scmnd->cmnd[0]) {
1030 		case ATA_16:
1031 		case ATA_12:
1032 			set_host_byte(scmnd, DID_PASSTHROUGH);
1033 			break;
1034 		/*
1035 		 * On some Hyper-V hosts TEST_UNIT_READY command can
1036 		 * return SRB_STATUS_ERROR. Let the upper level code
1037 		 * deal with it based on the sense information.
1038 		 */
1039 		case TEST_UNIT_READY:
1040 			break;
1041 		default:
1042 			set_host_byte(scmnd, DID_ERROR);
1043 		}
1044 		return;
1045 
1046 	case SRB_STATUS_INVALID_LUN:
1047 		set_host_byte(scmnd, DID_NO_CONNECT);
1048 		process_err_fn = storvsc_remove_lun;
1049 		goto do_work;
1050 
1051 	}
1052 	return;
1053 
1054 do_work:
1055 	/*
1056 	 * We need to schedule work to process this error; schedule it.
1057 	 */
1058 	wrk = kmalloc(sizeof(struct storvsc_scan_work), GFP_ATOMIC);
1059 	if (!wrk) {
1060 		set_host_byte(scmnd, DID_BAD_TARGET);
1061 		return;
1062 	}
1063 
1064 	wrk->host = host;
1065 	wrk->lun = vm_srb->lun;
1066 	wrk->tgt_id = vm_srb->target_id;
1067 	INIT_WORK(&wrk->work, process_err_fn);
1068 	queue_work(host_dev->handle_error_wq, &wrk->work);
1069 }
1070 
1071 
1072 static void storvsc_command_completion(struct storvsc_cmd_request *cmd_request,
1073 				       struct storvsc_device *stor_dev)
1074 {
1075 	struct scsi_cmnd *scmnd = cmd_request->cmd;
1076 	struct scsi_sense_hdr sense_hdr;
1077 	struct vmscsi_request *vm_srb;
1078 	u32 data_transfer_length;
1079 	struct Scsi_Host *host;
1080 	u32 payload_sz = cmd_request->payload_sz;
1081 	void *payload = cmd_request->payload;
1082 	bool sense_ok;
1083 
1084 	host = stor_dev->host;
1085 
1086 	vm_srb = &cmd_request->vstor_packet.vm_srb;
1087 	data_transfer_length = vm_srb->data_transfer_length;
1088 
1089 	scmnd->result = vm_srb->scsi_status;
1090 
1091 	if (scmnd->result) {
1092 		sense_ok = scsi_normalize_sense(scmnd->sense_buffer,
1093 				SCSI_SENSE_BUFFERSIZE, &sense_hdr);
1094 
1095 		if (sense_ok && do_logging(STORVSC_LOGGING_WARN))
1096 			scsi_print_sense_hdr(scmnd->device, "storvsc",
1097 					     &sense_hdr);
1098 	}
1099 
1100 	if (vm_srb->srb_status != SRB_STATUS_SUCCESS) {
1101 		storvsc_handle_error(vm_srb, scmnd, host, sense_hdr.asc,
1102 					 sense_hdr.ascq);
1103 		/*
1104 		 * The Windows driver set data_transfer_length on
1105 		 * SRB_STATUS_DATA_OVERRUN. On other errors, this value
1106 		 * is untouched.  In these cases we set it to 0.
1107 		 */
1108 		if (vm_srb->srb_status != SRB_STATUS_DATA_OVERRUN)
1109 			data_transfer_length = 0;
1110 	}
1111 
1112 	/* Validate data_transfer_length (from Hyper-V) */
1113 	if (data_transfer_length > cmd_request->payload->range.len)
1114 		data_transfer_length = cmd_request->payload->range.len;
1115 
1116 	scsi_set_resid(scmnd,
1117 		cmd_request->payload->range.len - data_transfer_length);
1118 
1119 	scsi_done(scmnd);
1120 
1121 	if (payload_sz >
1122 		sizeof(struct vmbus_channel_packet_multipage_buffer))
1123 		kfree(payload);
1124 }
1125 
1126 static void storvsc_on_io_completion(struct storvsc_device *stor_device,
1127 				  struct vstor_packet *vstor_packet,
1128 				  struct storvsc_cmd_request *request)
1129 {
1130 	struct vstor_packet *stor_pkt;
1131 	struct hv_device *device = stor_device->device;
1132 
1133 	stor_pkt = &request->vstor_packet;
1134 
1135 	/*
1136 	 * The current SCSI handling on the host side does
1137 	 * not correctly handle:
1138 	 * INQUIRY command with page code parameter set to 0x80
1139 	 * MODE_SENSE command with cmd[2] == 0x1c
1140 	 *
1141 	 * Setup srb and scsi status so this won't be fatal.
1142 	 * We do this so we can distinguish truly fatal failues
1143 	 * (srb status == 0x4) and off-line the device in that case.
1144 	 */
1145 
1146 	if ((stor_pkt->vm_srb.cdb[0] == INQUIRY) ||
1147 	   (stor_pkt->vm_srb.cdb[0] == MODE_SENSE)) {
1148 		vstor_packet->vm_srb.scsi_status = 0;
1149 		vstor_packet->vm_srb.srb_status = SRB_STATUS_SUCCESS;
1150 	}
1151 
1152 	/* Copy over the status...etc */
1153 	stor_pkt->vm_srb.scsi_status = vstor_packet->vm_srb.scsi_status;
1154 	stor_pkt->vm_srb.srb_status = vstor_packet->vm_srb.srb_status;
1155 
1156 	/*
1157 	 * Copy over the sense_info_length, but limit to the known max
1158 	 * size if Hyper-V returns a bad value.
1159 	 */
1160 	stor_pkt->vm_srb.sense_info_length = min_t(u8, STORVSC_SENSE_BUFFER_SIZE,
1161 		vstor_packet->vm_srb.sense_info_length);
1162 
1163 	if (vstor_packet->vm_srb.scsi_status != 0 ||
1164 	    vstor_packet->vm_srb.srb_status != SRB_STATUS_SUCCESS) {
1165 
1166 		/*
1167 		 * Log TEST_UNIT_READY errors only as warnings. Hyper-V can
1168 		 * return errors when detecting devices using TEST_UNIT_READY,
1169 		 * and logging these as errors produces unhelpful noise.
1170 		 */
1171 		int loglevel = (stor_pkt->vm_srb.cdb[0] == TEST_UNIT_READY) ?
1172 			STORVSC_LOGGING_WARN : STORVSC_LOGGING_ERROR;
1173 
1174 		storvsc_log(device, loglevel,
1175 			"tag#%d cmd 0x%x status: scsi 0x%x srb 0x%x hv 0x%x\n",
1176 			scsi_cmd_to_rq(request->cmd)->tag,
1177 			stor_pkt->vm_srb.cdb[0],
1178 			vstor_packet->vm_srb.scsi_status,
1179 			vstor_packet->vm_srb.srb_status,
1180 			vstor_packet->status);
1181 	}
1182 
1183 	if (vstor_packet->vm_srb.scsi_status == SAM_STAT_CHECK_CONDITION &&
1184 	    (vstor_packet->vm_srb.srb_status & SRB_STATUS_AUTOSENSE_VALID))
1185 		memcpy(request->cmd->sense_buffer,
1186 		       vstor_packet->vm_srb.sense_data,
1187 		       stor_pkt->vm_srb.sense_info_length);
1188 
1189 	stor_pkt->vm_srb.data_transfer_length =
1190 		vstor_packet->vm_srb.data_transfer_length;
1191 
1192 	storvsc_command_completion(request, stor_device);
1193 
1194 	if (atomic_dec_and_test(&stor_device->num_outstanding_req) &&
1195 		stor_device->drain_notify)
1196 		wake_up(&stor_device->waiting_to_drain);
1197 }
1198 
1199 static void storvsc_on_receive(struct storvsc_device *stor_device,
1200 			     struct vstor_packet *vstor_packet,
1201 			     struct storvsc_cmd_request *request)
1202 {
1203 	struct hv_host_device *host_dev;
1204 	switch (vstor_packet->operation) {
1205 	case VSTOR_OPERATION_COMPLETE_IO:
1206 		storvsc_on_io_completion(stor_device, vstor_packet, request);
1207 		break;
1208 
1209 	case VSTOR_OPERATION_REMOVE_DEVICE:
1210 	case VSTOR_OPERATION_ENUMERATE_BUS:
1211 		host_dev = shost_priv(stor_device->host);
1212 		queue_work(
1213 			host_dev->handle_error_wq, &host_dev->host_scan_work);
1214 		break;
1215 
1216 	case VSTOR_OPERATION_FCHBA_DATA:
1217 		cache_wwn(stor_device, vstor_packet);
1218 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
1219 		fc_host_node_name(stor_device->host) = stor_device->node_name;
1220 		fc_host_port_name(stor_device->host) = stor_device->port_name;
1221 #endif
1222 		break;
1223 	default:
1224 		break;
1225 	}
1226 }
1227 
1228 static void storvsc_on_channel_callback(void *context)
1229 {
1230 	struct vmbus_channel *channel = (struct vmbus_channel *)context;
1231 	const struct vmpacket_descriptor *desc;
1232 	struct hv_device *device;
1233 	struct storvsc_device *stor_device;
1234 	struct Scsi_Host *shost;
1235 	unsigned long time_limit = jiffies + msecs_to_jiffies(CALLBACK_TIMEOUT);
1236 
1237 	if (channel->primary_channel != NULL)
1238 		device = channel->primary_channel->device_obj;
1239 	else
1240 		device = channel->device_obj;
1241 
1242 	stor_device = get_in_stor_device(device);
1243 	if (!stor_device)
1244 		return;
1245 
1246 	shost = stor_device->host;
1247 
1248 	foreach_vmbus_pkt(desc, channel) {
1249 		struct vstor_packet *packet = hv_pkt_data(desc);
1250 		struct storvsc_cmd_request *request = NULL;
1251 		u32 pktlen = hv_pkt_datalen(desc);
1252 		u64 rqst_id = desc->trans_id;
1253 		u32 minlen = rqst_id ? sizeof(struct vstor_packet) :
1254 			sizeof(enum vstor_packet_operation);
1255 
1256 		if (unlikely(time_after(jiffies, time_limit))) {
1257 			hv_pkt_iter_close(channel);
1258 			return;
1259 		}
1260 
1261 		if (pktlen < minlen) {
1262 			dev_err(&device->device,
1263 				"Invalid pkt: id=%llu, len=%u, minlen=%u\n",
1264 				rqst_id, pktlen, minlen);
1265 			continue;
1266 		}
1267 
1268 		if (rqst_id == VMBUS_RQST_INIT) {
1269 			request = &stor_device->init_request;
1270 		} else if (rqst_id == VMBUS_RQST_RESET) {
1271 			request = &stor_device->reset_request;
1272 		} else {
1273 			/* Hyper-V can send an unsolicited message with ID of 0 */
1274 			if (rqst_id == 0) {
1275 				/*
1276 				 * storvsc_on_receive() looks at the vstor_packet in the message
1277 				 * from the ring buffer.
1278 				 *
1279 				 * - If the operation in the vstor_packet is COMPLETE_IO, then
1280 				 *   we call storvsc_on_io_completion(), and dereference the
1281 				 *   guest memory address.  Make sure we don't call
1282 				 *   storvsc_on_io_completion() with a guest memory address
1283 				 *   that is zero if Hyper-V were to construct and send such
1284 				 *   a bogus packet.
1285 				 *
1286 				 * - If the operation in the vstor_packet is FCHBA_DATA, then
1287 				 *   we call cache_wwn(), and access the data payload area of
1288 				 *   the packet (wwn_packet); however, there is no guarantee
1289 				 *   that the packet is big enough to contain such area.
1290 				 *   Future-proof the code by rejecting such a bogus packet.
1291 				 */
1292 				if (packet->operation == VSTOR_OPERATION_COMPLETE_IO ||
1293 				    packet->operation == VSTOR_OPERATION_FCHBA_DATA) {
1294 					dev_err(&device->device, "Invalid packet with ID of 0\n");
1295 					continue;
1296 				}
1297 			} else {
1298 				struct scsi_cmnd *scmnd;
1299 
1300 				/* Transaction 'rqst_id' corresponds to tag 'rqst_id - 1' */
1301 				scmnd = scsi_host_find_tag(shost, rqst_id - 1);
1302 				if (scmnd == NULL) {
1303 					dev_err(&device->device, "Incorrect transaction ID\n");
1304 					continue;
1305 				}
1306 				request = (struct storvsc_cmd_request *)scsi_cmd_priv(scmnd);
1307 				scsi_dma_unmap(scmnd);
1308 			}
1309 
1310 			storvsc_on_receive(stor_device, packet, request);
1311 			continue;
1312 		}
1313 
1314 		memcpy(&request->vstor_packet, packet,
1315 		       sizeof(struct vstor_packet));
1316 		complete(&request->wait_event);
1317 	}
1318 }
1319 
1320 static int storvsc_connect_to_vsp(struct hv_device *device, u32 ring_size,
1321 				  bool is_fc)
1322 {
1323 	struct vmstorage_channel_properties props;
1324 	int ret;
1325 
1326 	memset(&props, 0, sizeof(struct vmstorage_channel_properties));
1327 
1328 	device->channel->max_pkt_size = STORVSC_MAX_PKT_SIZE;
1329 	device->channel->next_request_id_callback = storvsc_next_request_id;
1330 
1331 	ret = vmbus_open(device->channel,
1332 			 ring_size,
1333 			 ring_size,
1334 			 (void *)&props,
1335 			 sizeof(struct vmstorage_channel_properties),
1336 			 storvsc_on_channel_callback, device->channel);
1337 
1338 	if (ret != 0)
1339 		return ret;
1340 
1341 	ret = storvsc_channel_init(device, is_fc);
1342 
1343 	return ret;
1344 }
1345 
1346 static int storvsc_dev_remove(struct hv_device *device)
1347 {
1348 	struct storvsc_device *stor_device;
1349 
1350 	stor_device = hv_get_drvdata(device);
1351 
1352 	stor_device->destroy = true;
1353 
1354 	/* Make sure flag is set before waiting */
1355 	wmb();
1356 
1357 	/*
1358 	 * At this point, all outbound traffic should be disable. We
1359 	 * only allow inbound traffic (responses) to proceed so that
1360 	 * outstanding requests can be completed.
1361 	 */
1362 
1363 	storvsc_wait_to_drain(stor_device);
1364 
1365 	/*
1366 	 * Since we have already drained, we don't need to busy wait
1367 	 * as was done in final_release_stor_device()
1368 	 * Note that we cannot set the ext pointer to NULL until
1369 	 * we have drained - to drain the outgoing packets, we need to
1370 	 * allow incoming packets.
1371 	 */
1372 	hv_set_drvdata(device, NULL);
1373 
1374 	/* Close the channel */
1375 	vmbus_close(device->channel);
1376 
1377 	kfree(stor_device->stor_chns);
1378 	kfree(stor_device);
1379 	return 0;
1380 }
1381 
1382 static struct vmbus_channel *get_og_chn(struct storvsc_device *stor_device,
1383 					u16 q_num)
1384 {
1385 	u16 slot = 0;
1386 	u16 hash_qnum;
1387 	const struct cpumask *node_mask;
1388 	int num_channels, tgt_cpu;
1389 
1390 	if (stor_device->num_sc == 0) {
1391 		stor_device->stor_chns[q_num] = stor_device->device->channel;
1392 		return stor_device->device->channel;
1393 	}
1394 
1395 	/*
1396 	 * Our channel array is sparsley populated and we
1397 	 * initiated I/O on a processor/hw-q that does not
1398 	 * currently have a designated channel. Fix this.
1399 	 * The strategy is simple:
1400 	 * I. Ensure NUMA locality
1401 	 * II. Distribute evenly (best effort)
1402 	 */
1403 
1404 	node_mask = cpumask_of_node(cpu_to_node(q_num));
1405 
1406 	num_channels = 0;
1407 	for_each_cpu(tgt_cpu, &stor_device->alloced_cpus) {
1408 		if (cpumask_test_cpu(tgt_cpu, node_mask))
1409 			num_channels++;
1410 	}
1411 	if (num_channels == 0) {
1412 		stor_device->stor_chns[q_num] = stor_device->device->channel;
1413 		return stor_device->device->channel;
1414 	}
1415 
1416 	hash_qnum = q_num;
1417 	while (hash_qnum >= num_channels)
1418 		hash_qnum -= num_channels;
1419 
1420 	for_each_cpu(tgt_cpu, &stor_device->alloced_cpus) {
1421 		if (!cpumask_test_cpu(tgt_cpu, node_mask))
1422 			continue;
1423 		if (slot == hash_qnum)
1424 			break;
1425 		slot++;
1426 	}
1427 
1428 	stor_device->stor_chns[q_num] = stor_device->stor_chns[tgt_cpu];
1429 
1430 	return stor_device->stor_chns[q_num];
1431 }
1432 
1433 
1434 static int storvsc_do_io(struct hv_device *device,
1435 			 struct storvsc_cmd_request *request, u16 q_num)
1436 {
1437 	struct storvsc_device *stor_device;
1438 	struct vstor_packet *vstor_packet;
1439 	struct vmbus_channel *outgoing_channel, *channel;
1440 	unsigned long flags;
1441 	int ret = 0;
1442 	const struct cpumask *node_mask;
1443 	int tgt_cpu;
1444 
1445 	vstor_packet = &request->vstor_packet;
1446 	stor_device = get_out_stor_device(device);
1447 
1448 	if (!stor_device)
1449 		return -ENODEV;
1450 
1451 
1452 	request->device  = device;
1453 	/*
1454 	 * Select an appropriate channel to send the request out.
1455 	 */
1456 	/* See storvsc_change_target_cpu(). */
1457 	outgoing_channel = READ_ONCE(stor_device->stor_chns[q_num]);
1458 	if (outgoing_channel != NULL) {
1459 		if (outgoing_channel->target_cpu == q_num) {
1460 			/*
1461 			 * Ideally, we want to pick a different channel if
1462 			 * available on the same NUMA node.
1463 			 */
1464 			node_mask = cpumask_of_node(cpu_to_node(q_num));
1465 			for_each_cpu_wrap(tgt_cpu,
1466 				 &stor_device->alloced_cpus, q_num + 1) {
1467 				if (!cpumask_test_cpu(tgt_cpu, node_mask))
1468 					continue;
1469 				if (tgt_cpu == q_num)
1470 					continue;
1471 				channel = READ_ONCE(
1472 					stor_device->stor_chns[tgt_cpu]);
1473 				if (channel == NULL)
1474 					continue;
1475 				if (hv_get_avail_to_write_percent(
1476 							&channel->outbound)
1477 						> ring_avail_percent_lowater) {
1478 					outgoing_channel = channel;
1479 					goto found_channel;
1480 				}
1481 			}
1482 
1483 			/*
1484 			 * All the other channels on the same NUMA node are
1485 			 * busy. Try to use the channel on the current CPU
1486 			 */
1487 			if (hv_get_avail_to_write_percent(
1488 						&outgoing_channel->outbound)
1489 					> ring_avail_percent_lowater)
1490 				goto found_channel;
1491 
1492 			/*
1493 			 * If we reach here, all the channels on the current
1494 			 * NUMA node are busy. Try to find a channel in
1495 			 * other NUMA nodes
1496 			 */
1497 			for_each_cpu(tgt_cpu, &stor_device->alloced_cpus) {
1498 				if (cpumask_test_cpu(tgt_cpu, node_mask))
1499 					continue;
1500 				channel = READ_ONCE(
1501 					stor_device->stor_chns[tgt_cpu]);
1502 				if (channel == NULL)
1503 					continue;
1504 				if (hv_get_avail_to_write_percent(
1505 							&channel->outbound)
1506 						> ring_avail_percent_lowater) {
1507 					outgoing_channel = channel;
1508 					goto found_channel;
1509 				}
1510 			}
1511 		}
1512 	} else {
1513 		spin_lock_irqsave(&stor_device->lock, flags);
1514 		outgoing_channel = stor_device->stor_chns[q_num];
1515 		if (outgoing_channel != NULL) {
1516 			spin_unlock_irqrestore(&stor_device->lock, flags);
1517 			goto found_channel;
1518 		}
1519 		outgoing_channel = get_og_chn(stor_device, q_num);
1520 		spin_unlock_irqrestore(&stor_device->lock, flags);
1521 	}
1522 
1523 found_channel:
1524 	vstor_packet->flags |= REQUEST_COMPLETION_FLAG;
1525 
1526 	vstor_packet->vm_srb.length = sizeof(struct vmscsi_request);
1527 
1528 
1529 	vstor_packet->vm_srb.sense_info_length = STORVSC_SENSE_BUFFER_SIZE;
1530 
1531 
1532 	vstor_packet->vm_srb.data_transfer_length =
1533 	request->payload->range.len;
1534 
1535 	vstor_packet->operation = VSTOR_OPERATION_EXECUTE_SRB;
1536 
1537 	if (request->payload->range.len) {
1538 
1539 		ret = vmbus_sendpacket_mpb_desc(outgoing_channel,
1540 				request->payload, request->payload_sz,
1541 				vstor_packet,
1542 				sizeof(struct vstor_packet),
1543 				(unsigned long)request);
1544 	} else {
1545 		ret = vmbus_sendpacket(outgoing_channel, vstor_packet,
1546 			       sizeof(struct vstor_packet),
1547 			       (unsigned long)request,
1548 			       VM_PKT_DATA_INBAND,
1549 			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
1550 	}
1551 
1552 	if (ret != 0)
1553 		return ret;
1554 
1555 	atomic_inc(&stor_device->num_outstanding_req);
1556 
1557 	return ret;
1558 }
1559 
1560 static int storvsc_device_alloc(struct scsi_device *sdevice)
1561 {
1562 	/*
1563 	 * Set blist flag to permit the reading of the VPD pages even when
1564 	 * the target may claim SPC-2 compliance. MSFT targets currently
1565 	 * claim SPC-2 compliance while they implement post SPC-2 features.
1566 	 * With this flag we can correctly handle WRITE_SAME_16 issues.
1567 	 *
1568 	 * Hypervisor reports SCSI_UNKNOWN type for DVD ROM device but
1569 	 * still supports REPORT LUN.
1570 	 */
1571 	sdevice->sdev_bflags = BLIST_REPORTLUN2 | BLIST_TRY_VPD_PAGES;
1572 
1573 	return 0;
1574 }
1575 
1576 static int storvsc_device_configure(struct scsi_device *sdevice)
1577 {
1578 	blk_queue_rq_timeout(sdevice->request_queue, (storvsc_timeout * HZ));
1579 
1580 	/* storvsc devices don't support MAINTENANCE_IN SCSI cmd */
1581 	sdevice->no_report_opcodes = 1;
1582 	sdevice->no_write_same = 1;
1583 
1584 	/*
1585 	 * If the host is WIN8 or WIN8 R2, claim conformance to SPC-3
1586 	 * if the device is a MSFT virtual device.  If the host is
1587 	 * WIN10 or newer, allow write_same.
1588 	 */
1589 	if (!strncmp(sdevice->vendor, "Msft", 4)) {
1590 		switch (vmstor_proto_version) {
1591 		case VMSTOR_PROTO_VERSION_WIN8:
1592 		case VMSTOR_PROTO_VERSION_WIN8_1:
1593 			sdevice->scsi_level = SCSI_SPC_3;
1594 			break;
1595 		}
1596 
1597 		if (vmstor_proto_version >= VMSTOR_PROTO_VERSION_WIN10)
1598 			sdevice->no_write_same = 0;
1599 	}
1600 
1601 	return 0;
1602 }
1603 
1604 static int storvsc_get_chs(struct scsi_device *sdev, struct block_device * bdev,
1605 			   sector_t capacity, int *info)
1606 {
1607 	sector_t nsect = capacity;
1608 	sector_t cylinders = nsect;
1609 	int heads, sectors_pt;
1610 
1611 	/*
1612 	 * We are making up these values; let us keep it simple.
1613 	 */
1614 	heads = 0xff;
1615 	sectors_pt = 0x3f;      /* Sectors per track */
1616 	sector_div(cylinders, heads * sectors_pt);
1617 	if ((sector_t)(cylinders + 1) * heads * sectors_pt < nsect)
1618 		cylinders = 0xffff;
1619 
1620 	info[0] = heads;
1621 	info[1] = sectors_pt;
1622 	info[2] = (int)cylinders;
1623 
1624 	return 0;
1625 }
1626 
1627 static int storvsc_host_reset_handler(struct scsi_cmnd *scmnd)
1628 {
1629 	struct hv_host_device *host_dev = shost_priv(scmnd->device->host);
1630 	struct hv_device *device = host_dev->dev;
1631 
1632 	struct storvsc_device *stor_device;
1633 	struct storvsc_cmd_request *request;
1634 	struct vstor_packet *vstor_packet;
1635 	int ret, t;
1636 
1637 	stor_device = get_out_stor_device(device);
1638 	if (!stor_device)
1639 		return FAILED;
1640 
1641 	request = &stor_device->reset_request;
1642 	vstor_packet = &request->vstor_packet;
1643 	memset(vstor_packet, 0, sizeof(struct vstor_packet));
1644 
1645 	init_completion(&request->wait_event);
1646 
1647 	vstor_packet->operation = VSTOR_OPERATION_RESET_BUS;
1648 	vstor_packet->flags = REQUEST_COMPLETION_FLAG;
1649 	vstor_packet->vm_srb.path_id = stor_device->path_id;
1650 
1651 	ret = vmbus_sendpacket(device->channel, vstor_packet,
1652 			       sizeof(struct vstor_packet),
1653 			       VMBUS_RQST_RESET,
1654 			       VM_PKT_DATA_INBAND,
1655 			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
1656 	if (ret != 0)
1657 		return FAILED;
1658 
1659 	t = wait_for_completion_timeout(&request->wait_event, 5*HZ);
1660 	if (t == 0)
1661 		return TIMEOUT_ERROR;
1662 
1663 
1664 	/*
1665 	 * At this point, all outstanding requests in the adapter
1666 	 * should have been flushed out and return to us
1667 	 * There is a potential race here where the host may be in
1668 	 * the process of responding when we return from here.
1669 	 * Just wait for all in-transit packets to be accounted for
1670 	 * before we return from here.
1671 	 */
1672 	storvsc_wait_to_drain(stor_device);
1673 
1674 	return SUCCESS;
1675 }
1676 
1677 /*
1678  * The host guarantees to respond to each command, although I/O latencies might
1679  * be unbounded on Azure.  Reset the timer unconditionally to give the host a
1680  * chance to perform EH.
1681  */
1682 static enum scsi_timeout_action storvsc_eh_timed_out(struct scsi_cmnd *scmnd)
1683 {
1684 	return SCSI_EH_RESET_TIMER;
1685 }
1686 
1687 static bool storvsc_scsi_cmd_ok(struct scsi_cmnd *scmnd)
1688 {
1689 	bool allowed = true;
1690 	u8 scsi_op = scmnd->cmnd[0];
1691 
1692 	switch (scsi_op) {
1693 	/* the host does not handle WRITE_SAME, log accident usage */
1694 	case WRITE_SAME:
1695 	/*
1696 	 * smartd sends this command and the host does not handle
1697 	 * this. So, don't send it.
1698 	 */
1699 	case SET_WINDOW:
1700 		set_host_byte(scmnd, DID_ERROR);
1701 		allowed = false;
1702 		break;
1703 	default:
1704 		break;
1705 	}
1706 	return allowed;
1707 }
1708 
1709 static int storvsc_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *scmnd)
1710 {
1711 	int ret;
1712 	struct hv_host_device *host_dev = shost_priv(host);
1713 	struct hv_device *dev = host_dev->dev;
1714 	struct storvsc_cmd_request *cmd_request = scsi_cmd_priv(scmnd);
1715 	struct scatterlist *sgl;
1716 	struct vmscsi_request *vm_srb;
1717 	struct vmbus_packet_mpb_array  *payload;
1718 	u32 payload_sz;
1719 	u32 length;
1720 
1721 	if (vmstor_proto_version <= VMSTOR_PROTO_VERSION_WIN8) {
1722 		/*
1723 		 * On legacy hosts filter unimplemented commands.
1724 		 * Future hosts are expected to correctly handle
1725 		 * unsupported commands. Furthermore, it is
1726 		 * possible that some of the currently
1727 		 * unsupported commands maybe supported in
1728 		 * future versions of the host.
1729 		 */
1730 		if (!storvsc_scsi_cmd_ok(scmnd)) {
1731 			scsi_done(scmnd);
1732 			return 0;
1733 		}
1734 	}
1735 
1736 	/* Setup the cmd request */
1737 	cmd_request->cmd = scmnd;
1738 
1739 	memset(&cmd_request->vstor_packet, 0, sizeof(struct vstor_packet));
1740 	vm_srb = &cmd_request->vstor_packet.vm_srb;
1741 	vm_srb->time_out_value = 60;
1742 
1743 	vm_srb->srb_flags |=
1744 		SRB_FLAGS_DISABLE_SYNCH_TRANSFER;
1745 
1746 	if (scmnd->device->tagged_supported) {
1747 		vm_srb->srb_flags |=
1748 		(SRB_FLAGS_QUEUE_ACTION_ENABLE | SRB_FLAGS_NO_QUEUE_FREEZE);
1749 		vm_srb->queue_tag = SP_UNTAGGED;
1750 		vm_srb->queue_action = SRB_SIMPLE_TAG_REQUEST;
1751 	}
1752 
1753 	/* Build the SRB */
1754 	switch (scmnd->sc_data_direction) {
1755 	case DMA_TO_DEVICE:
1756 		vm_srb->data_in = WRITE_TYPE;
1757 		vm_srb->srb_flags |= SRB_FLAGS_DATA_OUT;
1758 		break;
1759 	case DMA_FROM_DEVICE:
1760 		vm_srb->data_in = READ_TYPE;
1761 		vm_srb->srb_flags |= SRB_FLAGS_DATA_IN;
1762 		break;
1763 	case DMA_NONE:
1764 		vm_srb->data_in = UNKNOWN_TYPE;
1765 		vm_srb->srb_flags |= SRB_FLAGS_NO_DATA_TRANSFER;
1766 		break;
1767 	default:
1768 		/*
1769 		 * This is DMA_BIDIRECTIONAL or something else we are never
1770 		 * supposed to see here.
1771 		 */
1772 		WARN(1, "Unexpected data direction: %d\n",
1773 		     scmnd->sc_data_direction);
1774 		return -EINVAL;
1775 	}
1776 
1777 
1778 	vm_srb->port_number = host_dev->port;
1779 	vm_srb->path_id = scmnd->device->channel;
1780 	vm_srb->target_id = scmnd->device->id;
1781 	vm_srb->lun = scmnd->device->lun;
1782 
1783 	vm_srb->cdb_length = scmnd->cmd_len;
1784 
1785 	memcpy(vm_srb->cdb, scmnd->cmnd, vm_srb->cdb_length);
1786 
1787 	sgl = (struct scatterlist *)scsi_sglist(scmnd);
1788 
1789 	length = scsi_bufflen(scmnd);
1790 	payload = (struct vmbus_packet_mpb_array *)&cmd_request->mpb;
1791 	payload_sz = 0;
1792 
1793 	if (scsi_sg_count(scmnd)) {
1794 		unsigned long offset_in_hvpg = offset_in_hvpage(sgl->offset);
1795 		unsigned int hvpg_count = HVPFN_UP(offset_in_hvpg + length);
1796 		struct scatterlist *sg;
1797 		unsigned long hvpfn, hvpfns_to_add;
1798 		int j, i = 0, sg_count;
1799 
1800 		payload_sz = (hvpg_count * sizeof(u64) +
1801 			      sizeof(struct vmbus_packet_mpb_array));
1802 
1803 		if (hvpg_count > MAX_PAGE_BUFFER_COUNT) {
1804 			payload = kzalloc(payload_sz, GFP_ATOMIC);
1805 			if (!payload)
1806 				return SCSI_MLQUEUE_DEVICE_BUSY;
1807 		}
1808 
1809 		payload->range.len = length;
1810 		payload->range.offset = offset_in_hvpg;
1811 
1812 		sg_count = scsi_dma_map(scmnd);
1813 		if (sg_count < 0) {
1814 			ret = SCSI_MLQUEUE_DEVICE_BUSY;
1815 			goto err_free_payload;
1816 		}
1817 
1818 		for_each_sg(sgl, sg, sg_count, j) {
1819 			/*
1820 			 * Init values for the current sgl entry. hvpfns_to_add
1821 			 * is in units of Hyper-V size pages. Handling the
1822 			 * PAGE_SIZE != HV_HYP_PAGE_SIZE case also handles
1823 			 * values of sgl->offset that are larger than PAGE_SIZE.
1824 			 * Such offsets are handled even on other than the first
1825 			 * sgl entry, provided they are a multiple of PAGE_SIZE.
1826 			 */
1827 			hvpfn = HVPFN_DOWN(sg_dma_address(sg));
1828 			hvpfns_to_add = HVPFN_UP(sg_dma_address(sg) +
1829 						 sg_dma_len(sg)) - hvpfn;
1830 
1831 			/*
1832 			 * Fill the next portion of the PFN array with
1833 			 * sequential Hyper-V PFNs for the continguous physical
1834 			 * memory described by the sgl entry. The end of the
1835 			 * last sgl should be reached at the same time that
1836 			 * the PFN array is filled.
1837 			 */
1838 			while (hvpfns_to_add--)
1839 				payload->range.pfn_array[i++] = hvpfn++;
1840 		}
1841 	}
1842 
1843 	cmd_request->payload = payload;
1844 	cmd_request->payload_sz = payload_sz;
1845 
1846 	/* Invokes the vsc to start an IO */
1847 	ret = storvsc_do_io(dev, cmd_request, get_cpu());
1848 	put_cpu();
1849 
1850 	if (ret)
1851 		scsi_dma_unmap(scmnd);
1852 
1853 	if (ret == -EAGAIN) {
1854 		/* no more space */
1855 		ret = SCSI_MLQUEUE_DEVICE_BUSY;
1856 		goto err_free_payload;
1857 	}
1858 
1859 	return 0;
1860 
1861 err_free_payload:
1862 	if (payload_sz > sizeof(cmd_request->mpb))
1863 		kfree(payload);
1864 
1865 	return ret;
1866 }
1867 
1868 static struct scsi_host_template scsi_driver = {
1869 	.module	=		THIS_MODULE,
1870 	.name =			"storvsc_host_t",
1871 	.cmd_size =             sizeof(struct storvsc_cmd_request),
1872 	.bios_param =		storvsc_get_chs,
1873 	.queuecommand =		storvsc_queuecommand,
1874 	.eh_host_reset_handler =	storvsc_host_reset_handler,
1875 	.proc_name =		"storvsc_host",
1876 	.eh_timed_out =		storvsc_eh_timed_out,
1877 	.slave_alloc =		storvsc_device_alloc,
1878 	.slave_configure =	storvsc_device_configure,
1879 	.cmd_per_lun =		2048,
1880 	.this_id =		-1,
1881 	/* Ensure there are no gaps in presented sgls */
1882 	.virt_boundary_mask =	HV_HYP_PAGE_SIZE - 1,
1883 	.no_write_same =	1,
1884 	.track_queue_depth =	1,
1885 	.change_queue_depth =	storvsc_change_queue_depth,
1886 };
1887 
1888 enum {
1889 	SCSI_GUID,
1890 	IDE_GUID,
1891 	SFC_GUID,
1892 };
1893 
1894 static const struct hv_vmbus_device_id id_table[] = {
1895 	/* SCSI guid */
1896 	{ HV_SCSI_GUID,
1897 	  .driver_data = SCSI_GUID
1898 	},
1899 	/* IDE guid */
1900 	{ HV_IDE_GUID,
1901 	  .driver_data = IDE_GUID
1902 	},
1903 	/* Fibre Channel GUID */
1904 	{
1905 	  HV_SYNTHFC_GUID,
1906 	  .driver_data = SFC_GUID
1907 	},
1908 	{ },
1909 };
1910 
1911 MODULE_DEVICE_TABLE(vmbus, id_table);
1912 
1913 static const struct { guid_t guid; } fc_guid = { HV_SYNTHFC_GUID };
1914 
1915 static bool hv_dev_is_fc(struct hv_device *hv_dev)
1916 {
1917 	return guid_equal(&fc_guid.guid, &hv_dev->dev_type);
1918 }
1919 
1920 static int storvsc_probe(struct hv_device *device,
1921 			const struct hv_vmbus_device_id *dev_id)
1922 {
1923 	int ret;
1924 	int num_cpus = num_online_cpus();
1925 	int num_present_cpus = num_present_cpus();
1926 	struct Scsi_Host *host;
1927 	struct hv_host_device *host_dev;
1928 	bool dev_is_ide = ((dev_id->driver_data == IDE_GUID) ? true : false);
1929 	bool is_fc = ((dev_id->driver_data == SFC_GUID) ? true : false);
1930 	int target = 0;
1931 	struct storvsc_device *stor_device;
1932 	int max_sub_channels = 0;
1933 	u32 max_xfer_bytes;
1934 
1935 	/*
1936 	 * We support sub-channels for storage on SCSI and FC controllers.
1937 	 * The number of sub-channels offerred is based on the number of
1938 	 * VCPUs in the guest.
1939 	 */
1940 	if (!dev_is_ide)
1941 		max_sub_channels =
1942 			(num_cpus - 1) / storvsc_vcpus_per_sub_channel;
1943 
1944 	scsi_driver.can_queue = max_outstanding_req_per_channel *
1945 				(max_sub_channels + 1) *
1946 				(100 - ring_avail_percent_lowater) / 100;
1947 
1948 	host = scsi_host_alloc(&scsi_driver,
1949 			       sizeof(struct hv_host_device));
1950 	if (!host)
1951 		return -ENOMEM;
1952 
1953 	host_dev = shost_priv(host);
1954 	memset(host_dev, 0, sizeof(struct hv_host_device));
1955 
1956 	host_dev->port = host->host_no;
1957 	host_dev->dev = device;
1958 	host_dev->host = host;
1959 
1960 
1961 	stor_device = kzalloc(sizeof(struct storvsc_device), GFP_KERNEL);
1962 	if (!stor_device) {
1963 		ret = -ENOMEM;
1964 		goto err_out0;
1965 	}
1966 
1967 	stor_device->destroy = false;
1968 	init_waitqueue_head(&stor_device->waiting_to_drain);
1969 	stor_device->device = device;
1970 	stor_device->host = host;
1971 	spin_lock_init(&stor_device->lock);
1972 	hv_set_drvdata(device, stor_device);
1973 	dma_set_min_align_mask(&device->device, HV_HYP_PAGE_SIZE - 1);
1974 
1975 	stor_device->port_number = host->host_no;
1976 	ret = storvsc_connect_to_vsp(device, storvsc_ringbuffer_size, is_fc);
1977 	if (ret)
1978 		goto err_out1;
1979 
1980 	host_dev->path = stor_device->path_id;
1981 	host_dev->target = stor_device->target_id;
1982 
1983 	switch (dev_id->driver_data) {
1984 	case SFC_GUID:
1985 		host->max_lun = STORVSC_FC_MAX_LUNS_PER_TARGET;
1986 		host->max_id = STORVSC_FC_MAX_TARGETS;
1987 		host->max_channel = STORVSC_FC_MAX_CHANNELS - 1;
1988 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
1989 		host->transportt = fc_transport_template;
1990 #endif
1991 		break;
1992 
1993 	case SCSI_GUID:
1994 		host->max_lun = STORVSC_MAX_LUNS_PER_TARGET;
1995 		host->max_id = STORVSC_MAX_TARGETS;
1996 		host->max_channel = STORVSC_MAX_CHANNELS - 1;
1997 		break;
1998 
1999 	default:
2000 		host->max_lun = STORVSC_IDE_MAX_LUNS_PER_TARGET;
2001 		host->max_id = STORVSC_IDE_MAX_TARGETS;
2002 		host->max_channel = STORVSC_IDE_MAX_CHANNELS - 1;
2003 		break;
2004 	}
2005 	/* max cmd length */
2006 	host->max_cmd_len = STORVSC_MAX_CMD_LEN;
2007 	/*
2008 	 * Any reasonable Hyper-V configuration should provide
2009 	 * max_transfer_bytes value aligning to HV_HYP_PAGE_SIZE,
2010 	 * protecting it from any weird value.
2011 	 */
2012 	max_xfer_bytes = round_down(stor_device->max_transfer_bytes, HV_HYP_PAGE_SIZE);
2013 	if (is_fc)
2014 		max_xfer_bytes = min(max_xfer_bytes, STORVSC_FC_MAX_XFER_SIZE);
2015 
2016 	/* max_hw_sectors_kb */
2017 	host->max_sectors = max_xfer_bytes >> 9;
2018 	/*
2019 	 * There are 2 requirements for Hyper-V storvsc sgl segments,
2020 	 * based on which the below calculation for max segments is
2021 	 * done:
2022 	 *
2023 	 * 1. Except for the first and last sgl segment, all sgl segments
2024 	 *    should be align to HV_HYP_PAGE_SIZE, that also means the
2025 	 *    maximum number of segments in a sgl can be calculated by
2026 	 *    dividing the total max transfer length by HV_HYP_PAGE_SIZE.
2027 	 *
2028 	 * 2. Except for the first and last, each entry in the SGL must
2029 	 *    have an offset that is a multiple of HV_HYP_PAGE_SIZE.
2030 	 */
2031 	host->sg_tablesize = (max_xfer_bytes >> HV_HYP_PAGE_SHIFT) + 1;
2032 	/*
2033 	 * For non-IDE disks, the host supports multiple channels.
2034 	 * Set the number of HW queues we are supporting.
2035 	 */
2036 	if (!dev_is_ide) {
2037 		if (storvsc_max_hw_queues > num_present_cpus) {
2038 			storvsc_max_hw_queues = 0;
2039 			storvsc_log(device, STORVSC_LOGGING_WARN,
2040 				"Resetting invalid storvsc_max_hw_queues value to default.\n");
2041 		}
2042 		if (storvsc_max_hw_queues)
2043 			host->nr_hw_queues = storvsc_max_hw_queues;
2044 		else
2045 			host->nr_hw_queues = num_present_cpus;
2046 	}
2047 
2048 	/*
2049 	 * Set the error handler work queue.
2050 	 */
2051 	host_dev->handle_error_wq =
2052 			alloc_ordered_workqueue("storvsc_error_wq_%d",
2053 						0,
2054 						host->host_no);
2055 	if (!host_dev->handle_error_wq) {
2056 		ret = -ENOMEM;
2057 		goto err_out2;
2058 	}
2059 	INIT_WORK(&host_dev->host_scan_work, storvsc_host_scan);
2060 	/* Register the HBA and start the scsi bus scan */
2061 	ret = scsi_add_host(host, &device->device);
2062 	if (ret != 0)
2063 		goto err_out3;
2064 
2065 	if (!dev_is_ide) {
2066 		scsi_scan_host(host);
2067 	} else {
2068 		target = (device->dev_instance.b[5] << 8 |
2069 			 device->dev_instance.b[4]);
2070 		ret = scsi_add_device(host, 0, target, 0);
2071 		if (ret)
2072 			goto err_out4;
2073 	}
2074 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
2075 	if (host->transportt == fc_transport_template) {
2076 		struct fc_rport_identifiers ids = {
2077 			.roles = FC_PORT_ROLE_FCP_DUMMY_INITIATOR,
2078 		};
2079 
2080 		fc_host_node_name(host) = stor_device->node_name;
2081 		fc_host_port_name(host) = stor_device->port_name;
2082 		stor_device->rport = fc_remote_port_add(host, 0, &ids);
2083 		if (!stor_device->rport) {
2084 			ret = -ENOMEM;
2085 			goto err_out4;
2086 		}
2087 	}
2088 #endif
2089 	return 0;
2090 
2091 err_out4:
2092 	scsi_remove_host(host);
2093 
2094 err_out3:
2095 	destroy_workqueue(host_dev->handle_error_wq);
2096 
2097 err_out2:
2098 	/*
2099 	 * Once we have connected with the host, we would need to
2100 	 * invoke storvsc_dev_remove() to rollback this state and
2101 	 * this call also frees up the stor_device; hence the jump around
2102 	 * err_out1 label.
2103 	 */
2104 	storvsc_dev_remove(device);
2105 	goto err_out0;
2106 
2107 err_out1:
2108 	kfree(stor_device->stor_chns);
2109 	kfree(stor_device);
2110 
2111 err_out0:
2112 	scsi_host_put(host);
2113 	return ret;
2114 }
2115 
2116 /* Change a scsi target's queue depth */
2117 static int storvsc_change_queue_depth(struct scsi_device *sdev, int queue_depth)
2118 {
2119 	if (queue_depth > scsi_driver.can_queue)
2120 		queue_depth = scsi_driver.can_queue;
2121 
2122 	return scsi_change_queue_depth(sdev, queue_depth);
2123 }
2124 
2125 static void storvsc_remove(struct hv_device *dev)
2126 {
2127 	struct storvsc_device *stor_device = hv_get_drvdata(dev);
2128 	struct Scsi_Host *host = stor_device->host;
2129 	struct hv_host_device *host_dev = shost_priv(host);
2130 
2131 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
2132 	if (host->transportt == fc_transport_template) {
2133 		fc_remote_port_delete(stor_device->rport);
2134 		fc_remove_host(host);
2135 	}
2136 #endif
2137 	destroy_workqueue(host_dev->handle_error_wq);
2138 	scsi_remove_host(host);
2139 	storvsc_dev_remove(dev);
2140 	scsi_host_put(host);
2141 }
2142 
2143 static int storvsc_suspend(struct hv_device *hv_dev)
2144 {
2145 	struct storvsc_device *stor_device = hv_get_drvdata(hv_dev);
2146 	struct Scsi_Host *host = stor_device->host;
2147 	struct hv_host_device *host_dev = shost_priv(host);
2148 
2149 	storvsc_wait_to_drain(stor_device);
2150 
2151 	drain_workqueue(host_dev->handle_error_wq);
2152 
2153 	vmbus_close(hv_dev->channel);
2154 
2155 	kfree(stor_device->stor_chns);
2156 	stor_device->stor_chns = NULL;
2157 
2158 	cpumask_clear(&stor_device->alloced_cpus);
2159 
2160 	return 0;
2161 }
2162 
2163 static int storvsc_resume(struct hv_device *hv_dev)
2164 {
2165 	int ret;
2166 
2167 	ret = storvsc_connect_to_vsp(hv_dev, storvsc_ringbuffer_size,
2168 				     hv_dev_is_fc(hv_dev));
2169 	return ret;
2170 }
2171 
2172 static struct hv_driver storvsc_drv = {
2173 	.name = KBUILD_MODNAME,
2174 	.id_table = id_table,
2175 	.probe = storvsc_probe,
2176 	.remove = storvsc_remove,
2177 	.suspend = storvsc_suspend,
2178 	.resume = storvsc_resume,
2179 	.driver = {
2180 		.probe_type = PROBE_PREFER_ASYNCHRONOUS,
2181 	},
2182 };
2183 
2184 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
2185 static struct fc_function_template fc_transport_functions = {
2186 	.show_host_node_name = 1,
2187 	.show_host_port_name = 1,
2188 };
2189 #endif
2190 
2191 static int __init storvsc_drv_init(void)
2192 {
2193 	int ret;
2194 
2195 	/*
2196 	 * Divide the ring buffer data size (which is 1 page less
2197 	 * than the ring buffer size since that page is reserved for
2198 	 * the ring buffer indices) by the max request size (which is
2199 	 * vmbus_channel_packet_multipage_buffer + struct vstor_packet + u64)
2200 	 */
2201 	max_outstanding_req_per_channel =
2202 		((storvsc_ringbuffer_size - PAGE_SIZE) /
2203 		ALIGN(MAX_MULTIPAGE_BUFFER_PACKET +
2204 		sizeof(struct vstor_packet) + sizeof(u64),
2205 		sizeof(u64)));
2206 
2207 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
2208 	fc_transport_template = fc_attach_transport(&fc_transport_functions);
2209 	if (!fc_transport_template)
2210 		return -ENODEV;
2211 #endif
2212 
2213 	ret = vmbus_driver_register(&storvsc_drv);
2214 
2215 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
2216 	if (ret)
2217 		fc_release_transport(fc_transport_template);
2218 #endif
2219 
2220 	return ret;
2221 }
2222 
2223 static void __exit storvsc_drv_exit(void)
2224 {
2225 	vmbus_driver_unregister(&storvsc_drv);
2226 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
2227 	fc_release_transport(fc_transport_template);
2228 #endif
2229 }
2230 
2231 MODULE_LICENSE("GPL");
2232 MODULE_DESCRIPTION("Microsoft Hyper-V virtual storage driver");
2233 module_init(storvsc_drv_init);
2234 module_exit(storvsc_drv_exit);
2235