xref: /openbmc/linux/drivers/scsi/storvsc_drv.c (revision 9b68f30b)
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 
322 #define SRB_STATUS(status) \
323 	(status & ~(SRB_STATUS_AUTOSENSE_VALID | SRB_STATUS_QUEUE_FROZEN))
324 /*
325  * This is the end of Protocol specific defines.
326  */
327 
328 static int storvsc_ringbuffer_size = (128 * 1024);
329 static u32 max_outstanding_req_per_channel;
330 static int storvsc_change_queue_depth(struct scsi_device *sdev, int queue_depth);
331 
332 static int storvsc_vcpus_per_sub_channel = 4;
333 static unsigned int storvsc_max_hw_queues;
334 
335 module_param(storvsc_ringbuffer_size, int, S_IRUGO);
336 MODULE_PARM_DESC(storvsc_ringbuffer_size, "Ring buffer size (bytes)");
337 
338 module_param(storvsc_max_hw_queues, uint, 0644);
339 MODULE_PARM_DESC(storvsc_max_hw_queues, "Maximum number of hardware queues");
340 
341 module_param(storvsc_vcpus_per_sub_channel, int, S_IRUGO);
342 MODULE_PARM_DESC(storvsc_vcpus_per_sub_channel, "Ratio of VCPUs to subchannels");
343 
344 static int ring_avail_percent_lowater = 10;
345 module_param(ring_avail_percent_lowater, int, S_IRUGO);
346 MODULE_PARM_DESC(ring_avail_percent_lowater,
347 		"Select a channel if available ring size > this in percent");
348 
349 /*
350  * Timeout in seconds for all devices managed by this driver.
351  */
352 static int storvsc_timeout = 180;
353 
354 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
355 static struct scsi_transport_template *fc_transport_template;
356 #endif
357 
358 static struct scsi_host_template scsi_driver;
359 static void storvsc_on_channel_callback(void *context);
360 
361 #define STORVSC_MAX_LUNS_PER_TARGET			255
362 #define STORVSC_MAX_TARGETS				2
363 #define STORVSC_MAX_CHANNELS				8
364 
365 #define STORVSC_FC_MAX_LUNS_PER_TARGET			255
366 #define STORVSC_FC_MAX_TARGETS				128
367 #define STORVSC_FC_MAX_CHANNELS				8
368 
369 #define STORVSC_IDE_MAX_LUNS_PER_TARGET			64
370 #define STORVSC_IDE_MAX_TARGETS				1
371 #define STORVSC_IDE_MAX_CHANNELS			1
372 
373 /*
374  * Upper bound on the size of a storvsc packet.
375  */
376 #define STORVSC_MAX_PKT_SIZE (sizeof(struct vmpacket_descriptor) +\
377 			      sizeof(struct vstor_packet))
378 
379 struct storvsc_cmd_request {
380 	struct scsi_cmnd *cmd;
381 
382 	struct hv_device *device;
383 
384 	/* Synchronize the request/response if needed */
385 	struct completion wait_event;
386 
387 	struct vmbus_channel_packet_multipage_buffer mpb;
388 	struct vmbus_packet_mpb_array *payload;
389 	u32 payload_sz;
390 
391 	struct vstor_packet vstor_packet;
392 };
393 
394 
395 /* A storvsc device is a device object that contains a vmbus channel */
396 struct storvsc_device {
397 	struct hv_device *device;
398 
399 	bool	 destroy;
400 	bool	 drain_notify;
401 	atomic_t num_outstanding_req;
402 	struct Scsi_Host *host;
403 
404 	wait_queue_head_t waiting_to_drain;
405 
406 	/*
407 	 * Each unique Port/Path/Target represents 1 channel ie scsi
408 	 * controller. In reality, the pathid, targetid is always 0
409 	 * and the port is set by us
410 	 */
411 	unsigned int port_number;
412 	unsigned char path_id;
413 	unsigned char target_id;
414 
415 	/*
416 	 * Max I/O, the device can support.
417 	 */
418 	u32   max_transfer_bytes;
419 	/*
420 	 * Number of sub-channels we will open.
421 	 */
422 	u16 num_sc;
423 	struct vmbus_channel **stor_chns;
424 	/*
425 	 * Mask of CPUs bound to subchannels.
426 	 */
427 	struct cpumask alloced_cpus;
428 	/*
429 	 * Serializes modifications of stor_chns[] from storvsc_do_io()
430 	 * and storvsc_change_target_cpu().
431 	 */
432 	spinlock_t lock;
433 	/* Used for vsc/vsp channel reset process */
434 	struct storvsc_cmd_request init_request;
435 	struct storvsc_cmd_request reset_request;
436 	/*
437 	 * Currently active port and node names for FC devices.
438 	 */
439 	u64 node_name;
440 	u64 port_name;
441 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
442 	struct fc_rport *rport;
443 #endif
444 };
445 
446 struct hv_host_device {
447 	struct hv_device *dev;
448 	unsigned int port;
449 	unsigned char path;
450 	unsigned char target;
451 	struct workqueue_struct *handle_error_wq;
452 	struct work_struct host_scan_work;
453 	struct Scsi_Host *host;
454 };
455 
456 struct storvsc_scan_work {
457 	struct work_struct work;
458 	struct Scsi_Host *host;
459 	u8 lun;
460 	u8 tgt_id;
461 };
462 
463 static void storvsc_device_scan(struct work_struct *work)
464 {
465 	struct storvsc_scan_work *wrk;
466 	struct scsi_device *sdev;
467 
468 	wrk = container_of(work, struct storvsc_scan_work, work);
469 
470 	sdev = scsi_device_lookup(wrk->host, 0, wrk->tgt_id, wrk->lun);
471 	if (!sdev)
472 		goto done;
473 	scsi_rescan_device(&sdev->sdev_gendev);
474 	scsi_device_put(sdev);
475 
476 done:
477 	kfree(wrk);
478 }
479 
480 static void storvsc_host_scan(struct work_struct *work)
481 {
482 	struct Scsi_Host *host;
483 	struct scsi_device *sdev;
484 	struct hv_host_device *host_device =
485 		container_of(work, struct hv_host_device, host_scan_work);
486 
487 	host = host_device->host;
488 	/*
489 	 * Before scanning the host, first check to see if any of the
490 	 * currently known devices have been hot removed. We issue a
491 	 * "unit ready" command against all currently known devices.
492 	 * This I/O will result in an error for devices that have been
493 	 * removed. As part of handling the I/O error, we remove the device.
494 	 *
495 	 * When a LUN is added or removed, the host sends us a signal to
496 	 * scan the host. Thus we are forced to discover the LUNs that
497 	 * may have been removed this way.
498 	 */
499 	mutex_lock(&host->scan_mutex);
500 	shost_for_each_device(sdev, host)
501 		scsi_test_unit_ready(sdev, 1, 1, NULL);
502 	mutex_unlock(&host->scan_mutex);
503 	/*
504 	 * Now scan the host to discover LUNs that may have been added.
505 	 */
506 	scsi_scan_host(host);
507 }
508 
509 static void storvsc_remove_lun(struct work_struct *work)
510 {
511 	struct storvsc_scan_work *wrk;
512 	struct scsi_device *sdev;
513 
514 	wrk = container_of(work, struct storvsc_scan_work, work);
515 	if (!scsi_host_get(wrk->host))
516 		goto done;
517 
518 	sdev = scsi_device_lookup(wrk->host, 0, wrk->tgt_id, wrk->lun);
519 
520 	if (sdev) {
521 		scsi_remove_device(sdev);
522 		scsi_device_put(sdev);
523 	}
524 	scsi_host_put(wrk->host);
525 
526 done:
527 	kfree(wrk);
528 }
529 
530 
531 /*
532  * We can get incoming messages from the host that are not in response to
533  * messages that we have sent out. An example of this would be messages
534  * received by the guest to notify dynamic addition/removal of LUNs. To
535  * deal with potential race conditions where the driver may be in the
536  * midst of being unloaded when we might receive an unsolicited message
537  * from the host, we have implemented a mechanism to gurantee sequential
538  * consistency:
539  *
540  * 1) Once the device is marked as being destroyed, we will fail all
541  *    outgoing messages.
542  * 2) We permit incoming messages when the device is being destroyed,
543  *    only to properly account for messages already sent out.
544  */
545 
546 static inline struct storvsc_device *get_out_stor_device(
547 					struct hv_device *device)
548 {
549 	struct storvsc_device *stor_device;
550 
551 	stor_device = hv_get_drvdata(device);
552 
553 	if (stor_device && stor_device->destroy)
554 		stor_device = NULL;
555 
556 	return stor_device;
557 }
558 
559 
560 static inline void storvsc_wait_to_drain(struct storvsc_device *dev)
561 {
562 	dev->drain_notify = true;
563 	wait_event(dev->waiting_to_drain,
564 		   atomic_read(&dev->num_outstanding_req) == 0);
565 	dev->drain_notify = false;
566 }
567 
568 static inline struct storvsc_device *get_in_stor_device(
569 					struct hv_device *device)
570 {
571 	struct storvsc_device *stor_device;
572 
573 	stor_device = hv_get_drvdata(device);
574 
575 	if (!stor_device)
576 		goto get_in_err;
577 
578 	/*
579 	 * If the device is being destroyed; allow incoming
580 	 * traffic only to cleanup outstanding requests.
581 	 */
582 
583 	if (stor_device->destroy  &&
584 		(atomic_read(&stor_device->num_outstanding_req) == 0))
585 		stor_device = NULL;
586 
587 get_in_err:
588 	return stor_device;
589 
590 }
591 
592 static void storvsc_change_target_cpu(struct vmbus_channel *channel, u32 old,
593 				      u32 new)
594 {
595 	struct storvsc_device *stor_device;
596 	struct vmbus_channel *cur_chn;
597 	bool old_is_alloced = false;
598 	struct hv_device *device;
599 	unsigned long flags;
600 	int cpu;
601 
602 	device = channel->primary_channel ?
603 			channel->primary_channel->device_obj
604 				: channel->device_obj;
605 	stor_device = get_out_stor_device(device);
606 	if (!stor_device)
607 		return;
608 
609 	/* See storvsc_do_io() -> get_og_chn(). */
610 	spin_lock_irqsave(&stor_device->lock, flags);
611 
612 	/*
613 	 * Determines if the storvsc device has other channels assigned to
614 	 * the "old" CPU to update the alloced_cpus mask and the stor_chns
615 	 * array.
616 	 */
617 	if (device->channel != channel && device->channel->target_cpu == old) {
618 		cur_chn = device->channel;
619 		old_is_alloced = true;
620 		goto old_is_alloced;
621 	}
622 	list_for_each_entry(cur_chn, &device->channel->sc_list, sc_list) {
623 		if (cur_chn == channel)
624 			continue;
625 		if (cur_chn->target_cpu == old) {
626 			old_is_alloced = true;
627 			goto old_is_alloced;
628 		}
629 	}
630 
631 old_is_alloced:
632 	if (old_is_alloced)
633 		WRITE_ONCE(stor_device->stor_chns[old], cur_chn);
634 	else
635 		cpumask_clear_cpu(old, &stor_device->alloced_cpus);
636 
637 	/* "Flush" the stor_chns array. */
638 	for_each_possible_cpu(cpu) {
639 		if (stor_device->stor_chns[cpu] && !cpumask_test_cpu(
640 					cpu, &stor_device->alloced_cpus))
641 			WRITE_ONCE(stor_device->stor_chns[cpu], NULL);
642 	}
643 
644 	WRITE_ONCE(stor_device->stor_chns[new], channel);
645 	cpumask_set_cpu(new, &stor_device->alloced_cpus);
646 
647 	spin_unlock_irqrestore(&stor_device->lock, flags);
648 }
649 
650 static u64 storvsc_next_request_id(struct vmbus_channel *channel, u64 rqst_addr)
651 {
652 	struct storvsc_cmd_request *request =
653 		(struct storvsc_cmd_request *)(unsigned long)rqst_addr;
654 
655 	if (rqst_addr == VMBUS_RQST_INIT)
656 		return VMBUS_RQST_INIT;
657 	if (rqst_addr == VMBUS_RQST_RESET)
658 		return VMBUS_RQST_RESET;
659 
660 	/*
661 	 * Cannot return an ID of 0, which is reserved for an unsolicited
662 	 * message from Hyper-V.
663 	 */
664 	return (u64)blk_mq_unique_tag(scsi_cmd_to_rq(request->cmd)) + 1;
665 }
666 
667 static void handle_sc_creation(struct vmbus_channel *new_sc)
668 {
669 	struct hv_device *device = new_sc->primary_channel->device_obj;
670 	struct device *dev = &device->device;
671 	struct storvsc_device *stor_device;
672 	struct vmstorage_channel_properties props;
673 	int ret;
674 
675 	stor_device = get_out_stor_device(device);
676 	if (!stor_device)
677 		return;
678 
679 	memset(&props, 0, sizeof(struct vmstorage_channel_properties));
680 	new_sc->max_pkt_size = STORVSC_MAX_PKT_SIZE;
681 
682 	new_sc->next_request_id_callback = storvsc_next_request_id;
683 
684 	ret = vmbus_open(new_sc,
685 			 storvsc_ringbuffer_size,
686 			 storvsc_ringbuffer_size,
687 			 (void *)&props,
688 			 sizeof(struct vmstorage_channel_properties),
689 			 storvsc_on_channel_callback, new_sc);
690 
691 	/* In case vmbus_open() fails, we don't use the sub-channel. */
692 	if (ret != 0) {
693 		dev_err(dev, "Failed to open sub-channel: err=%d\n", ret);
694 		return;
695 	}
696 
697 	new_sc->change_target_cpu_callback = storvsc_change_target_cpu;
698 
699 	/* Add the sub-channel to the array of available channels. */
700 	stor_device->stor_chns[new_sc->target_cpu] = new_sc;
701 	cpumask_set_cpu(new_sc->target_cpu, &stor_device->alloced_cpus);
702 }
703 
704 static void  handle_multichannel_storage(struct hv_device *device, int max_chns)
705 {
706 	struct device *dev = &device->device;
707 	struct storvsc_device *stor_device;
708 	int num_sc;
709 	struct storvsc_cmd_request *request;
710 	struct vstor_packet *vstor_packet;
711 	int ret, t;
712 
713 	/*
714 	 * If the number of CPUs is artificially restricted, such as
715 	 * with maxcpus=1 on the kernel boot line, Hyper-V could offer
716 	 * sub-channels >= the number of CPUs. These sub-channels
717 	 * should not be created. The primary channel is already created
718 	 * and assigned to one CPU, so check against # CPUs - 1.
719 	 */
720 	num_sc = min((int)(num_online_cpus() - 1), max_chns);
721 	if (!num_sc)
722 		return;
723 
724 	stor_device = get_out_stor_device(device);
725 	if (!stor_device)
726 		return;
727 
728 	stor_device->num_sc = num_sc;
729 	request = &stor_device->init_request;
730 	vstor_packet = &request->vstor_packet;
731 
732 	/*
733 	 * Establish a handler for dealing with subchannels.
734 	 */
735 	vmbus_set_sc_create_callback(device->channel, handle_sc_creation);
736 
737 	/*
738 	 * Request the host to create sub-channels.
739 	 */
740 	memset(request, 0, sizeof(struct storvsc_cmd_request));
741 	init_completion(&request->wait_event);
742 	vstor_packet->operation = VSTOR_OPERATION_CREATE_SUB_CHANNELS;
743 	vstor_packet->flags = REQUEST_COMPLETION_FLAG;
744 	vstor_packet->sub_channel_count = num_sc;
745 
746 	ret = vmbus_sendpacket(device->channel, vstor_packet,
747 			       sizeof(struct vstor_packet),
748 			       VMBUS_RQST_INIT,
749 			       VM_PKT_DATA_INBAND,
750 			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
751 
752 	if (ret != 0) {
753 		dev_err(dev, "Failed to create sub-channel: err=%d\n", ret);
754 		return;
755 	}
756 
757 	t = wait_for_completion_timeout(&request->wait_event, 10*HZ);
758 	if (t == 0) {
759 		dev_err(dev, "Failed to create sub-channel: timed out\n");
760 		return;
761 	}
762 
763 	if (vstor_packet->operation != VSTOR_OPERATION_COMPLETE_IO ||
764 	    vstor_packet->status != 0) {
765 		dev_err(dev, "Failed to create sub-channel: op=%d, sts=%d\n",
766 			vstor_packet->operation, vstor_packet->status);
767 		return;
768 	}
769 
770 	/*
771 	 * We need to do nothing here, because vmbus_process_offer()
772 	 * invokes channel->sc_creation_callback, which will open and use
773 	 * the sub-channel(s).
774 	 */
775 }
776 
777 static void cache_wwn(struct storvsc_device *stor_device,
778 		      struct vstor_packet *vstor_packet)
779 {
780 	/*
781 	 * Cache the currently active port and node ww names.
782 	 */
783 	if (vstor_packet->wwn_packet.primary_active) {
784 		stor_device->node_name =
785 			wwn_to_u64(vstor_packet->wwn_packet.primary_node_wwn);
786 		stor_device->port_name =
787 			wwn_to_u64(vstor_packet->wwn_packet.primary_port_wwn);
788 	} else {
789 		stor_device->node_name =
790 			wwn_to_u64(vstor_packet->wwn_packet.secondary_node_wwn);
791 		stor_device->port_name =
792 			wwn_to_u64(vstor_packet->wwn_packet.secondary_port_wwn);
793 	}
794 }
795 
796 
797 static int storvsc_execute_vstor_op(struct hv_device *device,
798 				    struct storvsc_cmd_request *request,
799 				    bool status_check)
800 {
801 	struct storvsc_device *stor_device;
802 	struct vstor_packet *vstor_packet;
803 	int ret, t;
804 
805 	stor_device = get_out_stor_device(device);
806 	if (!stor_device)
807 		return -ENODEV;
808 
809 	vstor_packet = &request->vstor_packet;
810 
811 	init_completion(&request->wait_event);
812 	vstor_packet->flags = REQUEST_COMPLETION_FLAG;
813 
814 	ret = vmbus_sendpacket(device->channel, vstor_packet,
815 			       sizeof(struct vstor_packet),
816 			       VMBUS_RQST_INIT,
817 			       VM_PKT_DATA_INBAND,
818 			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
819 	if (ret != 0)
820 		return ret;
821 
822 	t = wait_for_completion_timeout(&request->wait_event, 5*HZ);
823 	if (t == 0)
824 		return -ETIMEDOUT;
825 
826 	if (!status_check)
827 		return ret;
828 
829 	if (vstor_packet->operation != VSTOR_OPERATION_COMPLETE_IO ||
830 	    vstor_packet->status != 0)
831 		return -EINVAL;
832 
833 	return ret;
834 }
835 
836 static int storvsc_channel_init(struct hv_device *device, bool is_fc)
837 {
838 	struct storvsc_device *stor_device;
839 	struct storvsc_cmd_request *request;
840 	struct vstor_packet *vstor_packet;
841 	int ret, i;
842 	int max_chns;
843 	bool process_sub_channels = false;
844 
845 	stor_device = get_out_stor_device(device);
846 	if (!stor_device)
847 		return -ENODEV;
848 
849 	request = &stor_device->init_request;
850 	vstor_packet = &request->vstor_packet;
851 
852 	/*
853 	 * Now, initiate the vsc/vsp initialization protocol on the open
854 	 * channel
855 	 */
856 	memset(request, 0, sizeof(struct storvsc_cmd_request));
857 	vstor_packet->operation = VSTOR_OPERATION_BEGIN_INITIALIZATION;
858 	ret = storvsc_execute_vstor_op(device, request, true);
859 	if (ret)
860 		return ret;
861 	/*
862 	 * Query host supported protocol version.
863 	 */
864 
865 	for (i = 0; i < ARRAY_SIZE(protocol_version); i++) {
866 		/* reuse the packet for version range supported */
867 		memset(vstor_packet, 0, sizeof(struct vstor_packet));
868 		vstor_packet->operation =
869 			VSTOR_OPERATION_QUERY_PROTOCOL_VERSION;
870 
871 		vstor_packet->version.major_minor = protocol_version[i];
872 
873 		/*
874 		 * The revision number is only used in Windows; set it to 0.
875 		 */
876 		vstor_packet->version.revision = 0;
877 		ret = storvsc_execute_vstor_op(device, request, false);
878 		if (ret != 0)
879 			return ret;
880 
881 		if (vstor_packet->operation != VSTOR_OPERATION_COMPLETE_IO)
882 			return -EINVAL;
883 
884 		if (vstor_packet->status == 0) {
885 			vmstor_proto_version = protocol_version[i];
886 
887 			break;
888 		}
889 	}
890 
891 	if (vstor_packet->status != 0) {
892 		dev_err(&device->device, "Obsolete Hyper-V version\n");
893 		return -EINVAL;
894 	}
895 
896 
897 	memset(vstor_packet, 0, sizeof(struct vstor_packet));
898 	vstor_packet->operation = VSTOR_OPERATION_QUERY_PROPERTIES;
899 	ret = storvsc_execute_vstor_op(device, request, true);
900 	if (ret != 0)
901 		return ret;
902 
903 	/*
904 	 * Check to see if multi-channel support is there.
905 	 * Hosts that implement protocol version of 5.1 and above
906 	 * support multi-channel.
907 	 */
908 	max_chns = vstor_packet->storage_channel_properties.max_channel_cnt;
909 
910 	/*
911 	 * Allocate state to manage the sub-channels.
912 	 * We allocate an array based on the numbers of possible CPUs
913 	 * (Hyper-V does not support cpu online/offline).
914 	 * This Array will be sparseley populated with unique
915 	 * channels - primary + sub-channels.
916 	 * We will however populate all the slots to evenly distribute
917 	 * the load.
918 	 */
919 	stor_device->stor_chns = kcalloc(num_possible_cpus(), sizeof(void *),
920 					 GFP_KERNEL);
921 	if (stor_device->stor_chns == NULL)
922 		return -ENOMEM;
923 
924 	device->channel->change_target_cpu_callback = storvsc_change_target_cpu;
925 
926 	stor_device->stor_chns[device->channel->target_cpu] = device->channel;
927 	cpumask_set_cpu(device->channel->target_cpu,
928 			&stor_device->alloced_cpus);
929 
930 	if (vstor_packet->storage_channel_properties.flags &
931 	    STORAGE_CHANNEL_SUPPORTS_MULTI_CHANNEL)
932 		process_sub_channels = true;
933 
934 	stor_device->max_transfer_bytes =
935 		vstor_packet->storage_channel_properties.max_transfer_bytes;
936 
937 	if (!is_fc)
938 		goto done;
939 
940 	/*
941 	 * For FC devices retrieve FC HBA data.
942 	 */
943 	memset(vstor_packet, 0, sizeof(struct vstor_packet));
944 	vstor_packet->operation = VSTOR_OPERATION_FCHBA_DATA;
945 	ret = storvsc_execute_vstor_op(device, request, true);
946 	if (ret != 0)
947 		return ret;
948 
949 	/*
950 	 * Cache the currently active port and node ww names.
951 	 */
952 	cache_wwn(stor_device, vstor_packet);
953 
954 done:
955 
956 	memset(vstor_packet, 0, sizeof(struct vstor_packet));
957 	vstor_packet->operation = VSTOR_OPERATION_END_INITIALIZATION;
958 	ret = storvsc_execute_vstor_op(device, request, true);
959 	if (ret != 0)
960 		return ret;
961 
962 	if (process_sub_channels)
963 		handle_multichannel_storage(device, max_chns);
964 
965 	return ret;
966 }
967 
968 static void storvsc_handle_error(struct vmscsi_request *vm_srb,
969 				struct scsi_cmnd *scmnd,
970 				struct Scsi_Host *host,
971 				u8 asc, u8 ascq)
972 {
973 	struct storvsc_scan_work *wrk;
974 	void (*process_err_fn)(struct work_struct *work);
975 	struct hv_host_device *host_dev = shost_priv(host);
976 
977 	switch (SRB_STATUS(vm_srb->srb_status)) {
978 	case SRB_STATUS_ERROR:
979 	case SRB_STATUS_ABORTED:
980 	case SRB_STATUS_INVALID_REQUEST:
981 		if (vm_srb->srb_status & SRB_STATUS_AUTOSENSE_VALID) {
982 			/* Check for capacity change */
983 			if ((asc == 0x2a) && (ascq == 0x9)) {
984 				process_err_fn = storvsc_device_scan;
985 				/* Retry the I/O that triggered this. */
986 				set_host_byte(scmnd, DID_REQUEUE);
987 				goto do_work;
988 			}
989 
990 			/*
991 			 * Check for "Operating parameters have changed"
992 			 * due to Hyper-V changing the VHD/VHDX BlockSize
993 			 * when adding/removing a differencing disk. This
994 			 * causes discard_granularity to change, so do a
995 			 * rescan to pick up the new granularity. We don't
996 			 * want scsi_report_sense() to output a message
997 			 * that a sysadmin wouldn't know what to do with.
998 			 */
999 			if ((asc == 0x3f) && (ascq != 0x03) &&
1000 					(ascq != 0x0e)) {
1001 				process_err_fn = storvsc_device_scan;
1002 				set_host_byte(scmnd, DID_REQUEUE);
1003 				goto do_work;
1004 			}
1005 
1006 			/*
1007 			 * Otherwise, let upper layer deal with the
1008 			 * error when sense message is present
1009 			 */
1010 			return;
1011 		}
1012 
1013 		/*
1014 		 * If there is an error; offline the device since all
1015 		 * error recovery strategies would have already been
1016 		 * deployed on the host side. However, if the command
1017 		 * were a pass-through command deal with it appropriately.
1018 		 */
1019 		switch (scmnd->cmnd[0]) {
1020 		case ATA_16:
1021 		case ATA_12:
1022 			set_host_byte(scmnd, DID_PASSTHROUGH);
1023 			break;
1024 		/*
1025 		 * On some Hyper-V hosts TEST_UNIT_READY command can
1026 		 * return SRB_STATUS_ERROR. Let the upper level code
1027 		 * deal with it based on the sense information.
1028 		 */
1029 		case TEST_UNIT_READY:
1030 			break;
1031 		default:
1032 			set_host_byte(scmnd, DID_ERROR);
1033 		}
1034 		return;
1035 
1036 	case SRB_STATUS_INVALID_LUN:
1037 		set_host_byte(scmnd, DID_NO_CONNECT);
1038 		process_err_fn = storvsc_remove_lun;
1039 		goto do_work;
1040 
1041 	}
1042 	return;
1043 
1044 do_work:
1045 	/*
1046 	 * We need to schedule work to process this error; schedule it.
1047 	 */
1048 	wrk = kmalloc(sizeof(struct storvsc_scan_work), GFP_ATOMIC);
1049 	if (!wrk) {
1050 		set_host_byte(scmnd, DID_BAD_TARGET);
1051 		return;
1052 	}
1053 
1054 	wrk->host = host;
1055 	wrk->lun = vm_srb->lun;
1056 	wrk->tgt_id = vm_srb->target_id;
1057 	INIT_WORK(&wrk->work, process_err_fn);
1058 	queue_work(host_dev->handle_error_wq, &wrk->work);
1059 }
1060 
1061 
1062 static void storvsc_command_completion(struct storvsc_cmd_request *cmd_request,
1063 				       struct storvsc_device *stor_dev)
1064 {
1065 	struct scsi_cmnd *scmnd = cmd_request->cmd;
1066 	struct scsi_sense_hdr sense_hdr;
1067 	struct vmscsi_request *vm_srb;
1068 	u32 data_transfer_length;
1069 	struct Scsi_Host *host;
1070 	u32 payload_sz = cmd_request->payload_sz;
1071 	void *payload = cmd_request->payload;
1072 	bool sense_ok;
1073 
1074 	host = stor_dev->host;
1075 
1076 	vm_srb = &cmd_request->vstor_packet.vm_srb;
1077 	data_transfer_length = vm_srb->data_transfer_length;
1078 
1079 	scmnd->result = vm_srb->scsi_status;
1080 
1081 	if (scmnd->result) {
1082 		sense_ok = scsi_normalize_sense(scmnd->sense_buffer,
1083 				SCSI_SENSE_BUFFERSIZE, &sense_hdr);
1084 
1085 		if (sense_ok && do_logging(STORVSC_LOGGING_WARN))
1086 			scsi_print_sense_hdr(scmnd->device, "storvsc",
1087 					     &sense_hdr);
1088 	}
1089 
1090 	if (vm_srb->srb_status != SRB_STATUS_SUCCESS) {
1091 		storvsc_handle_error(vm_srb, scmnd, host, sense_hdr.asc,
1092 					 sense_hdr.ascq);
1093 		/*
1094 		 * The Windows driver set data_transfer_length on
1095 		 * SRB_STATUS_DATA_OVERRUN. On other errors, this value
1096 		 * is untouched.  In these cases we set it to 0.
1097 		 */
1098 		if (vm_srb->srb_status != SRB_STATUS_DATA_OVERRUN)
1099 			data_transfer_length = 0;
1100 	}
1101 
1102 	/* Validate data_transfer_length (from Hyper-V) */
1103 	if (data_transfer_length > cmd_request->payload->range.len)
1104 		data_transfer_length = cmd_request->payload->range.len;
1105 
1106 	scsi_set_resid(scmnd,
1107 		cmd_request->payload->range.len - data_transfer_length);
1108 
1109 	scsi_done(scmnd);
1110 
1111 	if (payload_sz >
1112 		sizeof(struct vmbus_channel_packet_multipage_buffer))
1113 		kfree(payload);
1114 }
1115 
1116 static void storvsc_on_io_completion(struct storvsc_device *stor_device,
1117 				  struct vstor_packet *vstor_packet,
1118 				  struct storvsc_cmd_request *request)
1119 {
1120 	struct vstor_packet *stor_pkt;
1121 	struct hv_device *device = stor_device->device;
1122 
1123 	stor_pkt = &request->vstor_packet;
1124 
1125 	/*
1126 	 * The current SCSI handling on the host side does
1127 	 * not correctly handle:
1128 	 * INQUIRY command with page code parameter set to 0x80
1129 	 * MODE_SENSE command with cmd[2] == 0x1c
1130 	 *
1131 	 * Setup srb and scsi status so this won't be fatal.
1132 	 * We do this so we can distinguish truly fatal failues
1133 	 * (srb status == 0x4) and off-line the device in that case.
1134 	 */
1135 
1136 	if ((stor_pkt->vm_srb.cdb[0] == INQUIRY) ||
1137 	   (stor_pkt->vm_srb.cdb[0] == MODE_SENSE)) {
1138 		vstor_packet->vm_srb.scsi_status = 0;
1139 		vstor_packet->vm_srb.srb_status = SRB_STATUS_SUCCESS;
1140 	}
1141 
1142 	/* Copy over the status...etc */
1143 	stor_pkt->vm_srb.scsi_status = vstor_packet->vm_srb.scsi_status;
1144 	stor_pkt->vm_srb.srb_status = vstor_packet->vm_srb.srb_status;
1145 
1146 	/*
1147 	 * Copy over the sense_info_length, but limit to the known max
1148 	 * size if Hyper-V returns a bad value.
1149 	 */
1150 	stor_pkt->vm_srb.sense_info_length = min_t(u8, STORVSC_SENSE_BUFFER_SIZE,
1151 		vstor_packet->vm_srb.sense_info_length);
1152 
1153 	if (vstor_packet->vm_srb.scsi_status != 0 ||
1154 	    vstor_packet->vm_srb.srb_status != SRB_STATUS_SUCCESS) {
1155 
1156 		/*
1157 		 * Log TEST_UNIT_READY errors only as warnings. Hyper-V can
1158 		 * return errors when detecting devices using TEST_UNIT_READY,
1159 		 * and logging these as errors produces unhelpful noise.
1160 		 */
1161 		int loglevel = (stor_pkt->vm_srb.cdb[0] == TEST_UNIT_READY) ?
1162 			STORVSC_LOGGING_WARN : STORVSC_LOGGING_ERROR;
1163 
1164 		storvsc_log(device, loglevel,
1165 			"tag#%d cmd 0x%x status: scsi 0x%x srb 0x%x hv 0x%x\n",
1166 			scsi_cmd_to_rq(request->cmd)->tag,
1167 			stor_pkt->vm_srb.cdb[0],
1168 			vstor_packet->vm_srb.scsi_status,
1169 			vstor_packet->vm_srb.srb_status,
1170 			vstor_packet->status);
1171 	}
1172 
1173 	if (vstor_packet->vm_srb.scsi_status == SAM_STAT_CHECK_CONDITION &&
1174 	    (vstor_packet->vm_srb.srb_status & SRB_STATUS_AUTOSENSE_VALID))
1175 		memcpy(request->cmd->sense_buffer,
1176 		       vstor_packet->vm_srb.sense_data,
1177 		       stor_pkt->vm_srb.sense_info_length);
1178 
1179 	stor_pkt->vm_srb.data_transfer_length =
1180 		vstor_packet->vm_srb.data_transfer_length;
1181 
1182 	storvsc_command_completion(request, stor_device);
1183 
1184 	if (atomic_dec_and_test(&stor_device->num_outstanding_req) &&
1185 		stor_device->drain_notify)
1186 		wake_up(&stor_device->waiting_to_drain);
1187 }
1188 
1189 static void storvsc_on_receive(struct storvsc_device *stor_device,
1190 			     struct vstor_packet *vstor_packet,
1191 			     struct storvsc_cmd_request *request)
1192 {
1193 	struct hv_host_device *host_dev;
1194 	switch (vstor_packet->operation) {
1195 	case VSTOR_OPERATION_COMPLETE_IO:
1196 		storvsc_on_io_completion(stor_device, vstor_packet, request);
1197 		break;
1198 
1199 	case VSTOR_OPERATION_REMOVE_DEVICE:
1200 	case VSTOR_OPERATION_ENUMERATE_BUS:
1201 		host_dev = shost_priv(stor_device->host);
1202 		queue_work(
1203 			host_dev->handle_error_wq, &host_dev->host_scan_work);
1204 		break;
1205 
1206 	case VSTOR_OPERATION_FCHBA_DATA:
1207 		cache_wwn(stor_device, vstor_packet);
1208 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
1209 		fc_host_node_name(stor_device->host) = stor_device->node_name;
1210 		fc_host_port_name(stor_device->host) = stor_device->port_name;
1211 #endif
1212 		break;
1213 	default:
1214 		break;
1215 	}
1216 }
1217 
1218 static void storvsc_on_channel_callback(void *context)
1219 {
1220 	struct vmbus_channel *channel = (struct vmbus_channel *)context;
1221 	const struct vmpacket_descriptor *desc;
1222 	struct hv_device *device;
1223 	struct storvsc_device *stor_device;
1224 	struct Scsi_Host *shost;
1225 	unsigned long time_limit = jiffies + msecs_to_jiffies(CALLBACK_TIMEOUT);
1226 
1227 	if (channel->primary_channel != NULL)
1228 		device = channel->primary_channel->device_obj;
1229 	else
1230 		device = channel->device_obj;
1231 
1232 	stor_device = get_in_stor_device(device);
1233 	if (!stor_device)
1234 		return;
1235 
1236 	shost = stor_device->host;
1237 
1238 	foreach_vmbus_pkt(desc, channel) {
1239 		struct vstor_packet *packet = hv_pkt_data(desc);
1240 		struct storvsc_cmd_request *request = NULL;
1241 		u32 pktlen = hv_pkt_datalen(desc);
1242 		u64 rqst_id = desc->trans_id;
1243 		u32 minlen = rqst_id ? sizeof(struct vstor_packet) :
1244 			sizeof(enum vstor_packet_operation);
1245 
1246 		if (unlikely(time_after(jiffies, time_limit))) {
1247 			hv_pkt_iter_close(channel);
1248 			return;
1249 		}
1250 
1251 		if (pktlen < minlen) {
1252 			dev_err(&device->device,
1253 				"Invalid pkt: id=%llu, len=%u, minlen=%u\n",
1254 				rqst_id, pktlen, minlen);
1255 			continue;
1256 		}
1257 
1258 		if (rqst_id == VMBUS_RQST_INIT) {
1259 			request = &stor_device->init_request;
1260 		} else if (rqst_id == VMBUS_RQST_RESET) {
1261 			request = &stor_device->reset_request;
1262 		} else {
1263 			/* Hyper-V can send an unsolicited message with ID of 0 */
1264 			if (rqst_id == 0) {
1265 				/*
1266 				 * storvsc_on_receive() looks at the vstor_packet in the message
1267 				 * from the ring buffer.
1268 				 *
1269 				 * - If the operation in the vstor_packet is COMPLETE_IO, then
1270 				 *   we call storvsc_on_io_completion(), and dereference the
1271 				 *   guest memory address.  Make sure we don't call
1272 				 *   storvsc_on_io_completion() with a guest memory address
1273 				 *   that is zero if Hyper-V were to construct and send such
1274 				 *   a bogus packet.
1275 				 *
1276 				 * - If the operation in the vstor_packet is FCHBA_DATA, then
1277 				 *   we call cache_wwn(), and access the data payload area of
1278 				 *   the packet (wwn_packet); however, there is no guarantee
1279 				 *   that the packet is big enough to contain such area.
1280 				 *   Future-proof the code by rejecting such a bogus packet.
1281 				 */
1282 				if (packet->operation == VSTOR_OPERATION_COMPLETE_IO ||
1283 				    packet->operation == VSTOR_OPERATION_FCHBA_DATA) {
1284 					dev_err(&device->device, "Invalid packet with ID of 0\n");
1285 					continue;
1286 				}
1287 			} else {
1288 				struct scsi_cmnd *scmnd;
1289 
1290 				/* Transaction 'rqst_id' corresponds to tag 'rqst_id - 1' */
1291 				scmnd = scsi_host_find_tag(shost, rqst_id - 1);
1292 				if (scmnd == NULL) {
1293 					dev_err(&device->device, "Incorrect transaction ID\n");
1294 					continue;
1295 				}
1296 				request = (struct storvsc_cmd_request *)scsi_cmd_priv(scmnd);
1297 				scsi_dma_unmap(scmnd);
1298 			}
1299 
1300 			storvsc_on_receive(stor_device, packet, request);
1301 			continue;
1302 		}
1303 
1304 		memcpy(&request->vstor_packet, packet,
1305 		       sizeof(struct vstor_packet));
1306 		complete(&request->wait_event);
1307 	}
1308 }
1309 
1310 static int storvsc_connect_to_vsp(struct hv_device *device, u32 ring_size,
1311 				  bool is_fc)
1312 {
1313 	struct vmstorage_channel_properties props;
1314 	int ret;
1315 
1316 	memset(&props, 0, sizeof(struct vmstorage_channel_properties));
1317 
1318 	device->channel->max_pkt_size = STORVSC_MAX_PKT_SIZE;
1319 	device->channel->next_request_id_callback = storvsc_next_request_id;
1320 
1321 	ret = vmbus_open(device->channel,
1322 			 ring_size,
1323 			 ring_size,
1324 			 (void *)&props,
1325 			 sizeof(struct vmstorage_channel_properties),
1326 			 storvsc_on_channel_callback, device->channel);
1327 
1328 	if (ret != 0)
1329 		return ret;
1330 
1331 	ret = storvsc_channel_init(device, is_fc);
1332 
1333 	return ret;
1334 }
1335 
1336 static int storvsc_dev_remove(struct hv_device *device)
1337 {
1338 	struct storvsc_device *stor_device;
1339 
1340 	stor_device = hv_get_drvdata(device);
1341 
1342 	stor_device->destroy = true;
1343 
1344 	/* Make sure flag is set before waiting */
1345 	wmb();
1346 
1347 	/*
1348 	 * At this point, all outbound traffic should be disable. We
1349 	 * only allow inbound traffic (responses) to proceed so that
1350 	 * outstanding requests can be completed.
1351 	 */
1352 
1353 	storvsc_wait_to_drain(stor_device);
1354 
1355 	/*
1356 	 * Since we have already drained, we don't need to busy wait
1357 	 * as was done in final_release_stor_device()
1358 	 * Note that we cannot set the ext pointer to NULL until
1359 	 * we have drained - to drain the outgoing packets, we need to
1360 	 * allow incoming packets.
1361 	 */
1362 	hv_set_drvdata(device, NULL);
1363 
1364 	/* Close the channel */
1365 	vmbus_close(device->channel);
1366 
1367 	kfree(stor_device->stor_chns);
1368 	kfree(stor_device);
1369 	return 0;
1370 }
1371 
1372 static struct vmbus_channel *get_og_chn(struct storvsc_device *stor_device,
1373 					u16 q_num)
1374 {
1375 	u16 slot = 0;
1376 	u16 hash_qnum;
1377 	const struct cpumask *node_mask;
1378 	int num_channels, tgt_cpu;
1379 
1380 	if (stor_device->num_sc == 0) {
1381 		stor_device->stor_chns[q_num] = stor_device->device->channel;
1382 		return stor_device->device->channel;
1383 	}
1384 
1385 	/*
1386 	 * Our channel array is sparsley populated and we
1387 	 * initiated I/O on a processor/hw-q that does not
1388 	 * currently have a designated channel. Fix this.
1389 	 * The strategy is simple:
1390 	 * I. Ensure NUMA locality
1391 	 * II. Distribute evenly (best effort)
1392 	 */
1393 
1394 	node_mask = cpumask_of_node(cpu_to_node(q_num));
1395 
1396 	num_channels = 0;
1397 	for_each_cpu(tgt_cpu, &stor_device->alloced_cpus) {
1398 		if (cpumask_test_cpu(tgt_cpu, node_mask))
1399 			num_channels++;
1400 	}
1401 	if (num_channels == 0) {
1402 		stor_device->stor_chns[q_num] = stor_device->device->channel;
1403 		return stor_device->device->channel;
1404 	}
1405 
1406 	hash_qnum = q_num;
1407 	while (hash_qnum >= num_channels)
1408 		hash_qnum -= num_channels;
1409 
1410 	for_each_cpu(tgt_cpu, &stor_device->alloced_cpus) {
1411 		if (!cpumask_test_cpu(tgt_cpu, node_mask))
1412 			continue;
1413 		if (slot == hash_qnum)
1414 			break;
1415 		slot++;
1416 	}
1417 
1418 	stor_device->stor_chns[q_num] = stor_device->stor_chns[tgt_cpu];
1419 
1420 	return stor_device->stor_chns[q_num];
1421 }
1422 
1423 
1424 static int storvsc_do_io(struct hv_device *device,
1425 			 struct storvsc_cmd_request *request, u16 q_num)
1426 {
1427 	struct storvsc_device *stor_device;
1428 	struct vstor_packet *vstor_packet;
1429 	struct vmbus_channel *outgoing_channel, *channel;
1430 	unsigned long flags;
1431 	int ret = 0;
1432 	const struct cpumask *node_mask;
1433 	int tgt_cpu;
1434 
1435 	vstor_packet = &request->vstor_packet;
1436 	stor_device = get_out_stor_device(device);
1437 
1438 	if (!stor_device)
1439 		return -ENODEV;
1440 
1441 
1442 	request->device  = device;
1443 	/*
1444 	 * Select an appropriate channel to send the request out.
1445 	 */
1446 	/* See storvsc_change_target_cpu(). */
1447 	outgoing_channel = READ_ONCE(stor_device->stor_chns[q_num]);
1448 	if (outgoing_channel != NULL) {
1449 		if (outgoing_channel->target_cpu == q_num) {
1450 			/*
1451 			 * Ideally, we want to pick a different channel if
1452 			 * available on the same NUMA node.
1453 			 */
1454 			node_mask = cpumask_of_node(cpu_to_node(q_num));
1455 			for_each_cpu_wrap(tgt_cpu,
1456 				 &stor_device->alloced_cpus, q_num + 1) {
1457 				if (!cpumask_test_cpu(tgt_cpu, node_mask))
1458 					continue;
1459 				if (tgt_cpu == q_num)
1460 					continue;
1461 				channel = READ_ONCE(
1462 					stor_device->stor_chns[tgt_cpu]);
1463 				if (channel == NULL)
1464 					continue;
1465 				if (hv_get_avail_to_write_percent(
1466 							&channel->outbound)
1467 						> ring_avail_percent_lowater) {
1468 					outgoing_channel = channel;
1469 					goto found_channel;
1470 				}
1471 			}
1472 
1473 			/*
1474 			 * All the other channels on the same NUMA node are
1475 			 * busy. Try to use the channel on the current CPU
1476 			 */
1477 			if (hv_get_avail_to_write_percent(
1478 						&outgoing_channel->outbound)
1479 					> ring_avail_percent_lowater)
1480 				goto found_channel;
1481 
1482 			/*
1483 			 * If we reach here, all the channels on the current
1484 			 * NUMA node are busy. Try to find a channel in
1485 			 * other NUMA nodes
1486 			 */
1487 			for_each_cpu(tgt_cpu, &stor_device->alloced_cpus) {
1488 				if (cpumask_test_cpu(tgt_cpu, node_mask))
1489 					continue;
1490 				channel = READ_ONCE(
1491 					stor_device->stor_chns[tgt_cpu]);
1492 				if (channel == NULL)
1493 					continue;
1494 				if (hv_get_avail_to_write_percent(
1495 							&channel->outbound)
1496 						> ring_avail_percent_lowater) {
1497 					outgoing_channel = channel;
1498 					goto found_channel;
1499 				}
1500 			}
1501 		}
1502 	} else {
1503 		spin_lock_irqsave(&stor_device->lock, flags);
1504 		outgoing_channel = stor_device->stor_chns[q_num];
1505 		if (outgoing_channel != NULL) {
1506 			spin_unlock_irqrestore(&stor_device->lock, flags);
1507 			goto found_channel;
1508 		}
1509 		outgoing_channel = get_og_chn(stor_device, q_num);
1510 		spin_unlock_irqrestore(&stor_device->lock, flags);
1511 	}
1512 
1513 found_channel:
1514 	vstor_packet->flags |= REQUEST_COMPLETION_FLAG;
1515 
1516 	vstor_packet->vm_srb.length = sizeof(struct vmscsi_request);
1517 
1518 
1519 	vstor_packet->vm_srb.sense_info_length = STORVSC_SENSE_BUFFER_SIZE;
1520 
1521 
1522 	vstor_packet->vm_srb.data_transfer_length =
1523 	request->payload->range.len;
1524 
1525 	vstor_packet->operation = VSTOR_OPERATION_EXECUTE_SRB;
1526 
1527 	if (request->payload->range.len) {
1528 
1529 		ret = vmbus_sendpacket_mpb_desc(outgoing_channel,
1530 				request->payload, request->payload_sz,
1531 				vstor_packet,
1532 				sizeof(struct vstor_packet),
1533 				(unsigned long)request);
1534 	} else {
1535 		ret = vmbus_sendpacket(outgoing_channel, vstor_packet,
1536 			       sizeof(struct vstor_packet),
1537 			       (unsigned long)request,
1538 			       VM_PKT_DATA_INBAND,
1539 			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
1540 	}
1541 
1542 	if (ret != 0)
1543 		return ret;
1544 
1545 	atomic_inc(&stor_device->num_outstanding_req);
1546 
1547 	return ret;
1548 }
1549 
1550 static int storvsc_device_alloc(struct scsi_device *sdevice)
1551 {
1552 	/*
1553 	 * Set blist flag to permit the reading of the VPD pages even when
1554 	 * the target may claim SPC-2 compliance. MSFT targets currently
1555 	 * claim SPC-2 compliance while they implement post SPC-2 features.
1556 	 * With this flag we can correctly handle WRITE_SAME_16 issues.
1557 	 *
1558 	 * Hypervisor reports SCSI_UNKNOWN type for DVD ROM device but
1559 	 * still supports REPORT LUN.
1560 	 */
1561 	sdevice->sdev_bflags = BLIST_REPORTLUN2 | BLIST_TRY_VPD_PAGES;
1562 
1563 	return 0;
1564 }
1565 
1566 static int storvsc_device_configure(struct scsi_device *sdevice)
1567 {
1568 	blk_queue_rq_timeout(sdevice->request_queue, (storvsc_timeout * HZ));
1569 
1570 	sdevice->no_write_same = 1;
1571 
1572 	/*
1573 	 * If the host is WIN8 or WIN8 R2, claim conformance to SPC-3
1574 	 * if the device is a MSFT virtual device.  If the host is
1575 	 * WIN10 or newer, allow write_same.
1576 	 */
1577 	if (!strncmp(sdevice->vendor, "Msft", 4)) {
1578 		switch (vmstor_proto_version) {
1579 		case VMSTOR_PROTO_VERSION_WIN8:
1580 		case VMSTOR_PROTO_VERSION_WIN8_1:
1581 			sdevice->scsi_level = SCSI_SPC_3;
1582 			break;
1583 		}
1584 
1585 		if (vmstor_proto_version >= VMSTOR_PROTO_VERSION_WIN10)
1586 			sdevice->no_write_same = 0;
1587 	}
1588 
1589 	return 0;
1590 }
1591 
1592 static int storvsc_get_chs(struct scsi_device *sdev, struct block_device * bdev,
1593 			   sector_t capacity, int *info)
1594 {
1595 	sector_t nsect = capacity;
1596 	sector_t cylinders = nsect;
1597 	int heads, sectors_pt;
1598 
1599 	/*
1600 	 * We are making up these values; let us keep it simple.
1601 	 */
1602 	heads = 0xff;
1603 	sectors_pt = 0x3f;      /* Sectors per track */
1604 	sector_div(cylinders, heads * sectors_pt);
1605 	if ((sector_t)(cylinders + 1) * heads * sectors_pt < nsect)
1606 		cylinders = 0xffff;
1607 
1608 	info[0] = heads;
1609 	info[1] = sectors_pt;
1610 	info[2] = (int)cylinders;
1611 
1612 	return 0;
1613 }
1614 
1615 static int storvsc_host_reset_handler(struct scsi_cmnd *scmnd)
1616 {
1617 	struct hv_host_device *host_dev = shost_priv(scmnd->device->host);
1618 	struct hv_device *device = host_dev->dev;
1619 
1620 	struct storvsc_device *stor_device;
1621 	struct storvsc_cmd_request *request;
1622 	struct vstor_packet *vstor_packet;
1623 	int ret, t;
1624 
1625 	stor_device = get_out_stor_device(device);
1626 	if (!stor_device)
1627 		return FAILED;
1628 
1629 	request = &stor_device->reset_request;
1630 	vstor_packet = &request->vstor_packet;
1631 	memset(vstor_packet, 0, sizeof(struct vstor_packet));
1632 
1633 	init_completion(&request->wait_event);
1634 
1635 	vstor_packet->operation = VSTOR_OPERATION_RESET_BUS;
1636 	vstor_packet->flags = REQUEST_COMPLETION_FLAG;
1637 	vstor_packet->vm_srb.path_id = stor_device->path_id;
1638 
1639 	ret = vmbus_sendpacket(device->channel, vstor_packet,
1640 			       sizeof(struct vstor_packet),
1641 			       VMBUS_RQST_RESET,
1642 			       VM_PKT_DATA_INBAND,
1643 			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
1644 	if (ret != 0)
1645 		return FAILED;
1646 
1647 	t = wait_for_completion_timeout(&request->wait_event, 5*HZ);
1648 	if (t == 0)
1649 		return TIMEOUT_ERROR;
1650 
1651 
1652 	/*
1653 	 * At this point, all outstanding requests in the adapter
1654 	 * should have been flushed out and return to us
1655 	 * There is a potential race here where the host may be in
1656 	 * the process of responding when we return from here.
1657 	 * Just wait for all in-transit packets to be accounted for
1658 	 * before we return from here.
1659 	 */
1660 	storvsc_wait_to_drain(stor_device);
1661 
1662 	return SUCCESS;
1663 }
1664 
1665 /*
1666  * The host guarantees to respond to each command, although I/O latencies might
1667  * be unbounded on Azure.  Reset the timer unconditionally to give the host a
1668  * chance to perform EH.
1669  */
1670 static enum scsi_timeout_action storvsc_eh_timed_out(struct scsi_cmnd *scmnd)
1671 {
1672 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
1673 	if (scmnd->device->host->transportt == fc_transport_template)
1674 		return fc_eh_timed_out(scmnd);
1675 #endif
1676 	return SCSI_EH_RESET_TIMER;
1677 }
1678 
1679 static bool storvsc_scsi_cmd_ok(struct scsi_cmnd *scmnd)
1680 {
1681 	bool allowed = true;
1682 	u8 scsi_op = scmnd->cmnd[0];
1683 
1684 	switch (scsi_op) {
1685 	/* the host does not handle WRITE_SAME, log accident usage */
1686 	case WRITE_SAME:
1687 	/*
1688 	 * smartd sends this command and the host does not handle
1689 	 * this. So, don't send it.
1690 	 */
1691 	case SET_WINDOW:
1692 		set_host_byte(scmnd, DID_ERROR);
1693 		allowed = false;
1694 		break;
1695 	default:
1696 		break;
1697 	}
1698 	return allowed;
1699 }
1700 
1701 static int storvsc_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *scmnd)
1702 {
1703 	int ret;
1704 	struct hv_host_device *host_dev = shost_priv(host);
1705 	struct hv_device *dev = host_dev->dev;
1706 	struct storvsc_cmd_request *cmd_request = scsi_cmd_priv(scmnd);
1707 	struct scatterlist *sgl;
1708 	struct vmscsi_request *vm_srb;
1709 	struct vmbus_packet_mpb_array  *payload;
1710 	u32 payload_sz;
1711 	u32 length;
1712 
1713 	if (vmstor_proto_version <= VMSTOR_PROTO_VERSION_WIN8) {
1714 		/*
1715 		 * On legacy hosts filter unimplemented commands.
1716 		 * Future hosts are expected to correctly handle
1717 		 * unsupported commands. Furthermore, it is
1718 		 * possible that some of the currently
1719 		 * unsupported commands maybe supported in
1720 		 * future versions of the host.
1721 		 */
1722 		if (!storvsc_scsi_cmd_ok(scmnd)) {
1723 			scsi_done(scmnd);
1724 			return 0;
1725 		}
1726 	}
1727 
1728 	/* Setup the cmd request */
1729 	cmd_request->cmd = scmnd;
1730 
1731 	memset(&cmd_request->vstor_packet, 0, sizeof(struct vstor_packet));
1732 	vm_srb = &cmd_request->vstor_packet.vm_srb;
1733 	vm_srb->time_out_value = 60;
1734 
1735 	vm_srb->srb_flags |=
1736 		SRB_FLAGS_DISABLE_SYNCH_TRANSFER;
1737 
1738 	if (scmnd->device->tagged_supported) {
1739 		vm_srb->srb_flags |=
1740 		(SRB_FLAGS_QUEUE_ACTION_ENABLE | SRB_FLAGS_NO_QUEUE_FREEZE);
1741 		vm_srb->queue_tag = SP_UNTAGGED;
1742 		vm_srb->queue_action = SRB_SIMPLE_TAG_REQUEST;
1743 	}
1744 
1745 	/* Build the SRB */
1746 	switch (scmnd->sc_data_direction) {
1747 	case DMA_TO_DEVICE:
1748 		vm_srb->data_in = WRITE_TYPE;
1749 		vm_srb->srb_flags |= SRB_FLAGS_DATA_OUT;
1750 		break;
1751 	case DMA_FROM_DEVICE:
1752 		vm_srb->data_in = READ_TYPE;
1753 		vm_srb->srb_flags |= SRB_FLAGS_DATA_IN;
1754 		break;
1755 	case DMA_NONE:
1756 		vm_srb->data_in = UNKNOWN_TYPE;
1757 		vm_srb->srb_flags |= SRB_FLAGS_NO_DATA_TRANSFER;
1758 		break;
1759 	default:
1760 		/*
1761 		 * This is DMA_BIDIRECTIONAL or something else we are never
1762 		 * supposed to see here.
1763 		 */
1764 		WARN(1, "Unexpected data direction: %d\n",
1765 		     scmnd->sc_data_direction);
1766 		return -EINVAL;
1767 	}
1768 
1769 
1770 	vm_srb->port_number = host_dev->port;
1771 	vm_srb->path_id = scmnd->device->channel;
1772 	vm_srb->target_id = scmnd->device->id;
1773 	vm_srb->lun = scmnd->device->lun;
1774 
1775 	vm_srb->cdb_length = scmnd->cmd_len;
1776 
1777 	memcpy(vm_srb->cdb, scmnd->cmnd, vm_srb->cdb_length);
1778 
1779 	sgl = (struct scatterlist *)scsi_sglist(scmnd);
1780 
1781 	length = scsi_bufflen(scmnd);
1782 	payload = (struct vmbus_packet_mpb_array *)&cmd_request->mpb;
1783 	payload_sz = 0;
1784 
1785 	if (scsi_sg_count(scmnd)) {
1786 		unsigned long offset_in_hvpg = offset_in_hvpage(sgl->offset);
1787 		unsigned int hvpg_count = HVPFN_UP(offset_in_hvpg + length);
1788 		struct scatterlist *sg;
1789 		unsigned long hvpfn, hvpfns_to_add;
1790 		int j, i = 0, sg_count;
1791 
1792 		payload_sz = (hvpg_count * sizeof(u64) +
1793 			      sizeof(struct vmbus_packet_mpb_array));
1794 
1795 		if (hvpg_count > MAX_PAGE_BUFFER_COUNT) {
1796 			payload = kzalloc(payload_sz, GFP_ATOMIC);
1797 			if (!payload)
1798 				return SCSI_MLQUEUE_DEVICE_BUSY;
1799 		}
1800 
1801 		payload->range.len = length;
1802 		payload->range.offset = offset_in_hvpg;
1803 
1804 		sg_count = scsi_dma_map(scmnd);
1805 		if (sg_count < 0) {
1806 			ret = SCSI_MLQUEUE_DEVICE_BUSY;
1807 			goto err_free_payload;
1808 		}
1809 
1810 		for_each_sg(sgl, sg, sg_count, j) {
1811 			/*
1812 			 * Init values for the current sgl entry. hvpfns_to_add
1813 			 * is in units of Hyper-V size pages. Handling the
1814 			 * PAGE_SIZE != HV_HYP_PAGE_SIZE case also handles
1815 			 * values of sgl->offset that are larger than PAGE_SIZE.
1816 			 * Such offsets are handled even on other than the first
1817 			 * sgl entry, provided they are a multiple of PAGE_SIZE.
1818 			 */
1819 			hvpfn = HVPFN_DOWN(sg_dma_address(sg));
1820 			hvpfns_to_add = HVPFN_UP(sg_dma_address(sg) +
1821 						 sg_dma_len(sg)) - hvpfn;
1822 
1823 			/*
1824 			 * Fill the next portion of the PFN array with
1825 			 * sequential Hyper-V PFNs for the continguous physical
1826 			 * memory described by the sgl entry. The end of the
1827 			 * last sgl should be reached at the same time that
1828 			 * the PFN array is filled.
1829 			 */
1830 			while (hvpfns_to_add--)
1831 				payload->range.pfn_array[i++] = hvpfn++;
1832 		}
1833 	}
1834 
1835 	cmd_request->payload = payload;
1836 	cmd_request->payload_sz = payload_sz;
1837 
1838 	/* Invokes the vsc to start an IO */
1839 	ret = storvsc_do_io(dev, cmd_request, get_cpu());
1840 	put_cpu();
1841 
1842 	if (ret)
1843 		scsi_dma_unmap(scmnd);
1844 
1845 	if (ret == -EAGAIN) {
1846 		/* no more space */
1847 		ret = SCSI_MLQUEUE_DEVICE_BUSY;
1848 		goto err_free_payload;
1849 	}
1850 
1851 	return 0;
1852 
1853 err_free_payload:
1854 	if (payload_sz > sizeof(cmd_request->mpb))
1855 		kfree(payload);
1856 
1857 	return ret;
1858 }
1859 
1860 static struct scsi_host_template scsi_driver = {
1861 	.module	=		THIS_MODULE,
1862 	.name =			"storvsc_host_t",
1863 	.cmd_size =             sizeof(struct storvsc_cmd_request),
1864 	.bios_param =		storvsc_get_chs,
1865 	.queuecommand =		storvsc_queuecommand,
1866 	.eh_host_reset_handler =	storvsc_host_reset_handler,
1867 	.proc_name =		"storvsc_host",
1868 	.eh_timed_out =		storvsc_eh_timed_out,
1869 	.slave_alloc =		storvsc_device_alloc,
1870 	.slave_configure =	storvsc_device_configure,
1871 	.cmd_per_lun =		2048,
1872 	.this_id =		-1,
1873 	/* Ensure there are no gaps in presented sgls */
1874 	.virt_boundary_mask =	HV_HYP_PAGE_SIZE - 1,
1875 	.no_write_same =	1,
1876 	.track_queue_depth =	1,
1877 	.change_queue_depth =	storvsc_change_queue_depth,
1878 };
1879 
1880 enum {
1881 	SCSI_GUID,
1882 	IDE_GUID,
1883 	SFC_GUID,
1884 };
1885 
1886 static const struct hv_vmbus_device_id id_table[] = {
1887 	/* SCSI guid */
1888 	{ HV_SCSI_GUID,
1889 	  .driver_data = SCSI_GUID
1890 	},
1891 	/* IDE guid */
1892 	{ HV_IDE_GUID,
1893 	  .driver_data = IDE_GUID
1894 	},
1895 	/* Fibre Channel GUID */
1896 	{
1897 	  HV_SYNTHFC_GUID,
1898 	  .driver_data = SFC_GUID
1899 	},
1900 	{ },
1901 };
1902 
1903 MODULE_DEVICE_TABLE(vmbus, id_table);
1904 
1905 static const struct { guid_t guid; } fc_guid = { HV_SYNTHFC_GUID };
1906 
1907 static bool hv_dev_is_fc(struct hv_device *hv_dev)
1908 {
1909 	return guid_equal(&fc_guid.guid, &hv_dev->dev_type);
1910 }
1911 
1912 static int storvsc_probe(struct hv_device *device,
1913 			const struct hv_vmbus_device_id *dev_id)
1914 {
1915 	int ret;
1916 	int num_cpus = num_online_cpus();
1917 	int num_present_cpus = num_present_cpus();
1918 	struct Scsi_Host *host;
1919 	struct hv_host_device *host_dev;
1920 	bool dev_is_ide = ((dev_id->driver_data == IDE_GUID) ? true : false);
1921 	bool is_fc = ((dev_id->driver_data == SFC_GUID) ? true : false);
1922 	int target = 0;
1923 	struct storvsc_device *stor_device;
1924 	int max_sub_channels = 0;
1925 	u32 max_xfer_bytes;
1926 
1927 	/*
1928 	 * We support sub-channels for storage on SCSI and FC controllers.
1929 	 * The number of sub-channels offerred is based on the number of
1930 	 * VCPUs in the guest.
1931 	 */
1932 	if (!dev_is_ide)
1933 		max_sub_channels =
1934 			(num_cpus - 1) / storvsc_vcpus_per_sub_channel;
1935 
1936 	scsi_driver.can_queue = max_outstanding_req_per_channel *
1937 				(max_sub_channels + 1) *
1938 				(100 - ring_avail_percent_lowater) / 100;
1939 
1940 	host = scsi_host_alloc(&scsi_driver,
1941 			       sizeof(struct hv_host_device));
1942 	if (!host)
1943 		return -ENOMEM;
1944 
1945 	host_dev = shost_priv(host);
1946 	memset(host_dev, 0, sizeof(struct hv_host_device));
1947 
1948 	host_dev->port = host->host_no;
1949 	host_dev->dev = device;
1950 	host_dev->host = host;
1951 
1952 
1953 	stor_device = kzalloc(sizeof(struct storvsc_device), GFP_KERNEL);
1954 	if (!stor_device) {
1955 		ret = -ENOMEM;
1956 		goto err_out0;
1957 	}
1958 
1959 	stor_device->destroy = false;
1960 	init_waitqueue_head(&stor_device->waiting_to_drain);
1961 	stor_device->device = device;
1962 	stor_device->host = host;
1963 	spin_lock_init(&stor_device->lock);
1964 	hv_set_drvdata(device, stor_device);
1965 	dma_set_min_align_mask(&device->device, HV_HYP_PAGE_SIZE - 1);
1966 
1967 	stor_device->port_number = host->host_no;
1968 	ret = storvsc_connect_to_vsp(device, storvsc_ringbuffer_size, is_fc);
1969 	if (ret)
1970 		goto err_out1;
1971 
1972 	host_dev->path = stor_device->path_id;
1973 	host_dev->target = stor_device->target_id;
1974 
1975 	switch (dev_id->driver_data) {
1976 	case SFC_GUID:
1977 		host->max_lun = STORVSC_FC_MAX_LUNS_PER_TARGET;
1978 		host->max_id = STORVSC_FC_MAX_TARGETS;
1979 		host->max_channel = STORVSC_FC_MAX_CHANNELS - 1;
1980 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
1981 		host->transportt = fc_transport_template;
1982 #endif
1983 		break;
1984 
1985 	case SCSI_GUID:
1986 		host->max_lun = STORVSC_MAX_LUNS_PER_TARGET;
1987 		host->max_id = STORVSC_MAX_TARGETS;
1988 		host->max_channel = STORVSC_MAX_CHANNELS - 1;
1989 		break;
1990 
1991 	default:
1992 		host->max_lun = STORVSC_IDE_MAX_LUNS_PER_TARGET;
1993 		host->max_id = STORVSC_IDE_MAX_TARGETS;
1994 		host->max_channel = STORVSC_IDE_MAX_CHANNELS - 1;
1995 		break;
1996 	}
1997 	/* max cmd length */
1998 	host->max_cmd_len = STORVSC_MAX_CMD_LEN;
1999 	/*
2000 	 * Any reasonable Hyper-V configuration should provide
2001 	 * max_transfer_bytes value aligning to HV_HYP_PAGE_SIZE,
2002 	 * protecting it from any weird value.
2003 	 */
2004 	max_xfer_bytes = round_down(stor_device->max_transfer_bytes, HV_HYP_PAGE_SIZE);
2005 	/* max_hw_sectors_kb */
2006 	host->max_sectors = max_xfer_bytes >> 9;
2007 	/*
2008 	 * There are 2 requirements for Hyper-V storvsc sgl segments,
2009 	 * based on which the below calculation for max segments is
2010 	 * done:
2011 	 *
2012 	 * 1. Except for the first and last sgl segment, all sgl segments
2013 	 *    should be align to HV_HYP_PAGE_SIZE, that also means the
2014 	 *    maximum number of segments in a sgl can be calculated by
2015 	 *    dividing the total max transfer length by HV_HYP_PAGE_SIZE.
2016 	 *
2017 	 * 2. Except for the first and last, each entry in the SGL must
2018 	 *    have an offset that is a multiple of HV_HYP_PAGE_SIZE.
2019 	 */
2020 	host->sg_tablesize = (max_xfer_bytes >> HV_HYP_PAGE_SHIFT) + 1;
2021 	/*
2022 	 * For non-IDE disks, the host supports multiple channels.
2023 	 * Set the number of HW queues we are supporting.
2024 	 */
2025 	if (!dev_is_ide) {
2026 		if (storvsc_max_hw_queues > num_present_cpus) {
2027 			storvsc_max_hw_queues = 0;
2028 			storvsc_log(device, STORVSC_LOGGING_WARN,
2029 				"Resetting invalid storvsc_max_hw_queues value to default.\n");
2030 		}
2031 		if (storvsc_max_hw_queues)
2032 			host->nr_hw_queues = storvsc_max_hw_queues;
2033 		else
2034 			host->nr_hw_queues = num_present_cpus;
2035 	}
2036 
2037 	/*
2038 	 * Set the error handler work queue.
2039 	 */
2040 	host_dev->handle_error_wq =
2041 			alloc_ordered_workqueue("storvsc_error_wq_%d",
2042 						0,
2043 						host->host_no);
2044 	if (!host_dev->handle_error_wq) {
2045 		ret = -ENOMEM;
2046 		goto err_out2;
2047 	}
2048 	INIT_WORK(&host_dev->host_scan_work, storvsc_host_scan);
2049 	/* Register the HBA and start the scsi bus scan */
2050 	ret = scsi_add_host(host, &device->device);
2051 	if (ret != 0)
2052 		goto err_out3;
2053 
2054 	if (!dev_is_ide) {
2055 		scsi_scan_host(host);
2056 	} else {
2057 		target = (device->dev_instance.b[5] << 8 |
2058 			 device->dev_instance.b[4]);
2059 		ret = scsi_add_device(host, 0, target, 0);
2060 		if (ret)
2061 			goto err_out4;
2062 	}
2063 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
2064 	if (host->transportt == fc_transport_template) {
2065 		struct fc_rport_identifiers ids = {
2066 			.roles = FC_PORT_ROLE_FCP_DUMMY_INITIATOR,
2067 		};
2068 
2069 		fc_host_node_name(host) = stor_device->node_name;
2070 		fc_host_port_name(host) = stor_device->port_name;
2071 		stor_device->rport = fc_remote_port_add(host, 0, &ids);
2072 		if (!stor_device->rport) {
2073 			ret = -ENOMEM;
2074 			goto err_out4;
2075 		}
2076 	}
2077 #endif
2078 	return 0;
2079 
2080 err_out4:
2081 	scsi_remove_host(host);
2082 
2083 err_out3:
2084 	destroy_workqueue(host_dev->handle_error_wq);
2085 
2086 err_out2:
2087 	/*
2088 	 * Once we have connected with the host, we would need to
2089 	 * invoke storvsc_dev_remove() to rollback this state and
2090 	 * this call also frees up the stor_device; hence the jump around
2091 	 * err_out1 label.
2092 	 */
2093 	storvsc_dev_remove(device);
2094 	goto err_out0;
2095 
2096 err_out1:
2097 	kfree(stor_device->stor_chns);
2098 	kfree(stor_device);
2099 
2100 err_out0:
2101 	scsi_host_put(host);
2102 	return ret;
2103 }
2104 
2105 /* Change a scsi target's queue depth */
2106 static int storvsc_change_queue_depth(struct scsi_device *sdev, int queue_depth)
2107 {
2108 	if (queue_depth > scsi_driver.can_queue)
2109 		queue_depth = scsi_driver.can_queue;
2110 
2111 	return scsi_change_queue_depth(sdev, queue_depth);
2112 }
2113 
2114 static void storvsc_remove(struct hv_device *dev)
2115 {
2116 	struct storvsc_device *stor_device = hv_get_drvdata(dev);
2117 	struct Scsi_Host *host = stor_device->host;
2118 	struct hv_host_device *host_dev = shost_priv(host);
2119 
2120 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
2121 	if (host->transportt == fc_transport_template) {
2122 		fc_remote_port_delete(stor_device->rport);
2123 		fc_remove_host(host);
2124 	}
2125 #endif
2126 	destroy_workqueue(host_dev->handle_error_wq);
2127 	scsi_remove_host(host);
2128 	storvsc_dev_remove(dev);
2129 	scsi_host_put(host);
2130 }
2131 
2132 static int storvsc_suspend(struct hv_device *hv_dev)
2133 {
2134 	struct storvsc_device *stor_device = hv_get_drvdata(hv_dev);
2135 	struct Scsi_Host *host = stor_device->host;
2136 	struct hv_host_device *host_dev = shost_priv(host);
2137 
2138 	storvsc_wait_to_drain(stor_device);
2139 
2140 	drain_workqueue(host_dev->handle_error_wq);
2141 
2142 	vmbus_close(hv_dev->channel);
2143 
2144 	kfree(stor_device->stor_chns);
2145 	stor_device->stor_chns = NULL;
2146 
2147 	cpumask_clear(&stor_device->alloced_cpus);
2148 
2149 	return 0;
2150 }
2151 
2152 static int storvsc_resume(struct hv_device *hv_dev)
2153 {
2154 	int ret;
2155 
2156 	ret = storvsc_connect_to_vsp(hv_dev, storvsc_ringbuffer_size,
2157 				     hv_dev_is_fc(hv_dev));
2158 	return ret;
2159 }
2160 
2161 static struct hv_driver storvsc_drv = {
2162 	.name = KBUILD_MODNAME,
2163 	.id_table = id_table,
2164 	.probe = storvsc_probe,
2165 	.remove = storvsc_remove,
2166 	.suspend = storvsc_suspend,
2167 	.resume = storvsc_resume,
2168 	.driver = {
2169 		.probe_type = PROBE_PREFER_ASYNCHRONOUS,
2170 	},
2171 };
2172 
2173 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
2174 static struct fc_function_template fc_transport_functions = {
2175 	.show_host_node_name = 1,
2176 	.show_host_port_name = 1,
2177 };
2178 #endif
2179 
2180 static int __init storvsc_drv_init(void)
2181 {
2182 	int ret;
2183 
2184 	/*
2185 	 * Divide the ring buffer data size (which is 1 page less
2186 	 * than the ring buffer size since that page is reserved for
2187 	 * the ring buffer indices) by the max request size (which is
2188 	 * vmbus_channel_packet_multipage_buffer + struct vstor_packet + u64)
2189 	 */
2190 	max_outstanding_req_per_channel =
2191 		((storvsc_ringbuffer_size - PAGE_SIZE) /
2192 		ALIGN(MAX_MULTIPAGE_BUFFER_PACKET +
2193 		sizeof(struct vstor_packet) + sizeof(u64),
2194 		sizeof(u64)));
2195 
2196 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
2197 	fc_transport_template = fc_attach_transport(&fc_transport_functions);
2198 	if (!fc_transport_template)
2199 		return -ENODEV;
2200 #endif
2201 
2202 	ret = vmbus_driver_register(&storvsc_drv);
2203 
2204 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
2205 	if (ret)
2206 		fc_release_transport(fc_transport_template);
2207 #endif
2208 
2209 	return ret;
2210 }
2211 
2212 static void __exit storvsc_drv_exit(void)
2213 {
2214 	vmbus_driver_unregister(&storvsc_drv);
2215 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
2216 	fc_release_transport(fc_transport_template);
2217 #endif
2218 }
2219 
2220 MODULE_LICENSE("GPL");
2221 MODULE_DESCRIPTION("Microsoft Hyper-V virtual storage driver");
2222 module_init(storvsc_drv_init);
2223 module_exit(storvsc_drv_exit);
2224