xref: /linux/drivers/scsi/storvsc_drv.c (revision c79c3c34f75d72a066e292b10aa50fc758c97c89)
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 <scsi/scsi.h>
25 #include <scsi/scsi_cmnd.h>
26 #include <scsi/scsi_host.h>
27 #include <scsi/scsi_device.h>
28 #include <scsi/scsi_tcq.h>
29 #include <scsi/scsi_eh.h>
30 #include <scsi/scsi_devinfo.h>
31 #include <scsi/scsi_dbg.h>
32 #include <scsi/scsi_transport_fc.h>
33 #include <scsi/scsi_transport.h>
34 
35 /*
36  * All wire protocol details (storage protocol between the guest and the host)
37  * are consolidated here.
38  *
39  * Begin protocol definitions.
40  */
41 
42 /*
43  * Version history:
44  * V1 Beta: 0.1
45  * V1 RC < 2008/1/31: 1.0
46  * V1 RC > 2008/1/31:  2.0
47  * Win7: 4.2
48  * Win8: 5.1
49  * Win8.1: 6.0
50  * Win10: 6.2
51  */
52 
53 #define VMSTOR_PROTO_VERSION(MAJOR_, MINOR_)	((((MAJOR_) & 0xff) << 8) | \
54 						(((MINOR_) & 0xff)))
55 
56 #define VMSTOR_PROTO_VERSION_WIN6	VMSTOR_PROTO_VERSION(2, 0)
57 #define VMSTOR_PROTO_VERSION_WIN7	VMSTOR_PROTO_VERSION(4, 2)
58 #define VMSTOR_PROTO_VERSION_WIN8	VMSTOR_PROTO_VERSION(5, 1)
59 #define VMSTOR_PROTO_VERSION_WIN8_1	VMSTOR_PROTO_VERSION(6, 0)
60 #define VMSTOR_PROTO_VERSION_WIN10	VMSTOR_PROTO_VERSION(6, 2)
61 
62 /*  Packet structure describing virtual storage requests. */
63 enum vstor_packet_operation {
64 	VSTOR_OPERATION_COMPLETE_IO		= 1,
65 	VSTOR_OPERATION_REMOVE_DEVICE		= 2,
66 	VSTOR_OPERATION_EXECUTE_SRB		= 3,
67 	VSTOR_OPERATION_RESET_LUN		= 4,
68 	VSTOR_OPERATION_RESET_ADAPTER		= 5,
69 	VSTOR_OPERATION_RESET_BUS		= 6,
70 	VSTOR_OPERATION_BEGIN_INITIALIZATION	= 7,
71 	VSTOR_OPERATION_END_INITIALIZATION	= 8,
72 	VSTOR_OPERATION_QUERY_PROTOCOL_VERSION	= 9,
73 	VSTOR_OPERATION_QUERY_PROPERTIES	= 10,
74 	VSTOR_OPERATION_ENUMERATE_BUS		= 11,
75 	VSTOR_OPERATION_FCHBA_DATA              = 12,
76 	VSTOR_OPERATION_CREATE_SUB_CHANNELS     = 13,
77 	VSTOR_OPERATION_MAXIMUM                 = 13
78 };
79 
80 /*
81  * WWN packet for Fibre Channel HBA
82  */
83 
84 struct hv_fc_wwn_packet {
85 	u8	primary_active;
86 	u8	reserved1[3];
87 	u8	primary_port_wwn[8];
88 	u8	primary_node_wwn[8];
89 	u8	secondary_port_wwn[8];
90 	u8	secondary_node_wwn[8];
91 };
92 
93 
94 
95 /*
96  * SRB Flag Bits
97  */
98 
99 #define SRB_FLAGS_QUEUE_ACTION_ENABLE		0x00000002
100 #define SRB_FLAGS_DISABLE_DISCONNECT		0x00000004
101 #define SRB_FLAGS_DISABLE_SYNCH_TRANSFER	0x00000008
102 #define SRB_FLAGS_BYPASS_FROZEN_QUEUE		0x00000010
103 #define SRB_FLAGS_DISABLE_AUTOSENSE		0x00000020
104 #define SRB_FLAGS_DATA_IN			0x00000040
105 #define SRB_FLAGS_DATA_OUT			0x00000080
106 #define SRB_FLAGS_NO_DATA_TRANSFER		0x00000000
107 #define SRB_FLAGS_UNSPECIFIED_DIRECTION	(SRB_FLAGS_DATA_IN | SRB_FLAGS_DATA_OUT)
108 #define SRB_FLAGS_NO_QUEUE_FREEZE		0x00000100
109 #define SRB_FLAGS_ADAPTER_CACHE_ENABLE		0x00000200
110 #define SRB_FLAGS_FREE_SENSE_BUFFER		0x00000400
111 
112 /*
113  * This flag indicates the request is part of the workflow for processing a D3.
114  */
115 #define SRB_FLAGS_D3_PROCESSING			0x00000800
116 #define SRB_FLAGS_IS_ACTIVE			0x00010000
117 #define SRB_FLAGS_ALLOCATED_FROM_ZONE		0x00020000
118 #define SRB_FLAGS_SGLIST_FROM_POOL		0x00040000
119 #define SRB_FLAGS_BYPASS_LOCKED_QUEUE		0x00080000
120 #define SRB_FLAGS_NO_KEEP_AWAKE			0x00100000
121 #define SRB_FLAGS_PORT_DRIVER_ALLOCSENSE	0x00200000
122 #define SRB_FLAGS_PORT_DRIVER_SENSEHASPORT	0x00400000
123 #define SRB_FLAGS_DONT_START_NEXT_PACKET	0x00800000
124 #define SRB_FLAGS_PORT_DRIVER_RESERVED		0x0F000000
125 #define SRB_FLAGS_CLASS_DRIVER_RESERVED		0xF0000000
126 
127 #define SP_UNTAGGED			((unsigned char) ~0)
128 #define SRB_SIMPLE_TAG_REQUEST		0x20
129 
130 /*
131  * Platform neutral description of a scsi request -
132  * this remains the same across the write regardless of 32/64 bit
133  * note: it's patterned off the SCSI_PASS_THROUGH structure
134  */
135 #define STORVSC_MAX_CMD_LEN			0x10
136 
137 #define POST_WIN7_STORVSC_SENSE_BUFFER_SIZE	0x14
138 #define PRE_WIN8_STORVSC_SENSE_BUFFER_SIZE	0x12
139 
140 #define STORVSC_SENSE_BUFFER_SIZE		0x14
141 #define STORVSC_MAX_BUF_LEN_WITH_PADDING	0x14
142 
143 /*
144  * Sense buffer size changed in win8; have a run-time
145  * variable to track the size we should use.  This value will
146  * likely change during protocol negotiation but it is valid
147  * to start by assuming pre-Win8.
148  */
149 static int sense_buffer_size = PRE_WIN8_STORVSC_SENSE_BUFFER_SIZE;
150 
151 /*
152  * The storage protocol version is determined during the
153  * initial exchange with the host.  It will indicate which
154  * storage functionality is available in the host.
155 */
156 static int vmstor_proto_version;
157 
158 #define STORVSC_LOGGING_NONE	0
159 #define STORVSC_LOGGING_ERROR	1
160 #define STORVSC_LOGGING_WARN	2
161 
162 static int logging_level = STORVSC_LOGGING_ERROR;
163 module_param(logging_level, int, S_IRUGO|S_IWUSR);
164 MODULE_PARM_DESC(logging_level,
165 	"Logging level, 0 - None, 1 - Error (default), 2 - Warning.");
166 
167 static inline bool do_logging(int level)
168 {
169 	return logging_level >= level;
170 }
171 
172 #define storvsc_log(dev, level, fmt, ...)			\
173 do {								\
174 	if (do_logging(level))					\
175 		dev_warn(&(dev)->device, fmt, ##__VA_ARGS__);	\
176 } while (0)
177 
178 struct vmscsi_win8_extension {
179 	/*
180 	 * The following were added in Windows 8
181 	 */
182 	u16 reserve;
183 	u8  queue_tag;
184 	u8  queue_action;
185 	u32 srb_flags;
186 	u32 time_out_value;
187 	u32 queue_sort_ey;
188 } __packed;
189 
190 struct vmscsi_request {
191 	u16 length;
192 	u8 srb_status;
193 	u8 scsi_status;
194 
195 	u8  port_number;
196 	u8  path_id;
197 	u8  target_id;
198 	u8  lun;
199 
200 	u8  cdb_length;
201 	u8  sense_info_length;
202 	u8  data_in;
203 	u8  reserved;
204 
205 	u32 data_transfer_length;
206 
207 	union {
208 		u8 cdb[STORVSC_MAX_CMD_LEN];
209 		u8 sense_data[STORVSC_SENSE_BUFFER_SIZE];
210 		u8 reserved_array[STORVSC_MAX_BUF_LEN_WITH_PADDING];
211 	};
212 	/*
213 	 * The following was added in win8.
214 	 */
215 	struct vmscsi_win8_extension win8_extension;
216 
217 } __attribute((packed));
218 
219 /*
220  * The list of storage protocols in order of preference.
221  */
222 struct vmstor_protocol {
223 	int protocol_version;
224 	int sense_buffer_size;
225 	int vmscsi_size_delta;
226 };
227 
228 
229 static const struct vmstor_protocol vmstor_protocols[] = {
230 	{
231 		VMSTOR_PROTO_VERSION_WIN10,
232 		POST_WIN7_STORVSC_SENSE_BUFFER_SIZE,
233 		0
234 	},
235 	{
236 		VMSTOR_PROTO_VERSION_WIN8_1,
237 		POST_WIN7_STORVSC_SENSE_BUFFER_SIZE,
238 		0
239 	},
240 	{
241 		VMSTOR_PROTO_VERSION_WIN8,
242 		POST_WIN7_STORVSC_SENSE_BUFFER_SIZE,
243 		0
244 	},
245 	{
246 		VMSTOR_PROTO_VERSION_WIN7,
247 		PRE_WIN8_STORVSC_SENSE_BUFFER_SIZE,
248 		sizeof(struct vmscsi_win8_extension),
249 	},
250 	{
251 		VMSTOR_PROTO_VERSION_WIN6,
252 		PRE_WIN8_STORVSC_SENSE_BUFFER_SIZE,
253 		sizeof(struct vmscsi_win8_extension),
254 	}
255 };
256 
257 
258 /*
259  * This structure is sent during the initialization phase to get the different
260  * properties of the channel.
261  */
262 
263 #define STORAGE_CHANNEL_SUPPORTS_MULTI_CHANNEL		0x1
264 
265 struct vmstorage_channel_properties {
266 	u32 reserved;
267 	u16 max_channel_cnt;
268 	u16 reserved1;
269 
270 	u32 flags;
271 	u32   max_transfer_bytes;
272 
273 	u64  reserved2;
274 } __packed;
275 
276 /*  This structure is sent during the storage protocol negotiations. */
277 struct vmstorage_protocol_version {
278 	/* Major (MSW) and minor (LSW) version numbers. */
279 	u16 major_minor;
280 
281 	/*
282 	 * Revision number is auto-incremented whenever this file is changed
283 	 * (See FILL_VMSTOR_REVISION macro above).  Mismatch does not
284 	 * definitely indicate incompatibility--but it does indicate mismatched
285 	 * builds.
286 	 * This is only used on the windows side. Just set it to 0.
287 	 */
288 	u16 revision;
289 } __packed;
290 
291 /* Channel Property Flags */
292 #define STORAGE_CHANNEL_REMOVABLE_FLAG		0x1
293 #define STORAGE_CHANNEL_EMULATED_IDE_FLAG	0x2
294 
295 struct vstor_packet {
296 	/* Requested operation type */
297 	enum vstor_packet_operation operation;
298 
299 	/*  Flags - see below for values */
300 	u32 flags;
301 
302 	/* Status of the request returned from the server side. */
303 	u32 status;
304 
305 	/* Data payload area */
306 	union {
307 		/*
308 		 * Structure used to forward SCSI commands from the
309 		 * client to the server.
310 		 */
311 		struct vmscsi_request vm_srb;
312 
313 		/* Structure used to query channel properties. */
314 		struct vmstorage_channel_properties storage_channel_properties;
315 
316 		/* Used during version negotiations. */
317 		struct vmstorage_protocol_version version;
318 
319 		/* Fibre channel address packet */
320 		struct hv_fc_wwn_packet wwn_packet;
321 
322 		/* Number of sub-channels to create */
323 		u16 sub_channel_count;
324 
325 		/* This will be the maximum of the union members */
326 		u8  buffer[0x34];
327 	};
328 } __packed;
329 
330 /*
331  * Packet Flags:
332  *
333  * This flag indicates that the server should send back a completion for this
334  * packet.
335  */
336 
337 #define REQUEST_COMPLETION_FLAG	0x1
338 
339 /* Matches Windows-end */
340 enum storvsc_request_type {
341 	WRITE_TYPE = 0,
342 	READ_TYPE,
343 	UNKNOWN_TYPE,
344 };
345 
346 /*
347  * SRB status codes and masks; a subset of the codes used here.
348  */
349 
350 #define SRB_STATUS_AUTOSENSE_VALID	0x80
351 #define SRB_STATUS_QUEUE_FROZEN		0x40
352 #define SRB_STATUS_INVALID_LUN	0x20
353 #define SRB_STATUS_SUCCESS	0x01
354 #define SRB_STATUS_ABORTED	0x02
355 #define SRB_STATUS_ERROR	0x04
356 #define SRB_STATUS_DATA_OVERRUN	0x12
357 
358 #define SRB_STATUS(status) \
359 	(status & ~(SRB_STATUS_AUTOSENSE_VALID | SRB_STATUS_QUEUE_FROZEN))
360 /*
361  * This is the end of Protocol specific defines.
362  */
363 
364 static int storvsc_ringbuffer_size = (128 * 1024);
365 static u32 max_outstanding_req_per_channel;
366 static int storvsc_change_queue_depth(struct scsi_device *sdev, int queue_depth);
367 
368 static int storvsc_vcpus_per_sub_channel = 4;
369 
370 module_param(storvsc_ringbuffer_size, int, S_IRUGO);
371 MODULE_PARM_DESC(storvsc_ringbuffer_size, "Ring buffer size (bytes)");
372 
373 module_param(storvsc_vcpus_per_sub_channel, int, S_IRUGO);
374 MODULE_PARM_DESC(storvsc_vcpus_per_sub_channel, "Ratio of VCPUs to subchannels");
375 
376 static int ring_avail_percent_lowater = 10;
377 module_param(ring_avail_percent_lowater, int, S_IRUGO);
378 MODULE_PARM_DESC(ring_avail_percent_lowater,
379 		"Select a channel if available ring size > this in percent");
380 
381 /*
382  * Timeout in seconds for all devices managed by this driver.
383  */
384 static int storvsc_timeout = 180;
385 
386 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
387 static struct scsi_transport_template *fc_transport_template;
388 #endif
389 
390 static struct scsi_host_template scsi_driver;
391 static void storvsc_on_channel_callback(void *context);
392 
393 #define STORVSC_MAX_LUNS_PER_TARGET			255
394 #define STORVSC_MAX_TARGETS				2
395 #define STORVSC_MAX_CHANNELS				8
396 
397 #define STORVSC_FC_MAX_LUNS_PER_TARGET			255
398 #define STORVSC_FC_MAX_TARGETS				128
399 #define STORVSC_FC_MAX_CHANNELS				8
400 
401 #define STORVSC_IDE_MAX_LUNS_PER_TARGET			64
402 #define STORVSC_IDE_MAX_TARGETS				1
403 #define STORVSC_IDE_MAX_CHANNELS			1
404 
405 struct storvsc_cmd_request {
406 	struct scsi_cmnd *cmd;
407 
408 	struct hv_device *device;
409 
410 	/* Synchronize the request/response if needed */
411 	struct completion wait_event;
412 
413 	struct vmbus_channel_packet_multipage_buffer mpb;
414 	struct vmbus_packet_mpb_array *payload;
415 	u32 payload_sz;
416 
417 	struct vstor_packet vstor_packet;
418 };
419 
420 
421 /* A storvsc device is a device object that contains a vmbus channel */
422 struct storvsc_device {
423 	struct hv_device *device;
424 
425 	bool	 destroy;
426 	bool	 drain_notify;
427 	atomic_t num_outstanding_req;
428 	struct Scsi_Host *host;
429 
430 	wait_queue_head_t waiting_to_drain;
431 
432 	/*
433 	 * Each unique Port/Path/Target represents 1 channel ie scsi
434 	 * controller. In reality, the pathid, targetid is always 0
435 	 * and the port is set by us
436 	 */
437 	unsigned int port_number;
438 	unsigned char path_id;
439 	unsigned char target_id;
440 
441 	/*
442 	 * The size of the vmscsi_request has changed in win8. The
443 	 * additional size is because of new elements added to the
444 	 * structure. These elements are valid only when we are talking
445 	 * to a win8 host.
446 	 * Track the correction to size we need to apply. This value
447 	 * will likely change during protocol negotiation but it is
448 	 * valid to start by assuming pre-Win8.
449 	 */
450 	int vmscsi_size_delta;
451 
452 	/*
453 	 * Max I/O, the device can support.
454 	 */
455 	u32   max_transfer_bytes;
456 	/*
457 	 * Number of sub-channels we will open.
458 	 */
459 	u16 num_sc;
460 	struct vmbus_channel **stor_chns;
461 	/*
462 	 * Mask of CPUs bound to subchannels.
463 	 */
464 	struct cpumask alloced_cpus;
465 	/*
466 	 * Serializes modifications of stor_chns[] from storvsc_do_io()
467 	 * and storvsc_change_target_cpu().
468 	 */
469 	spinlock_t lock;
470 	/* Used for vsc/vsp channel reset process */
471 	struct storvsc_cmd_request init_request;
472 	struct storvsc_cmd_request reset_request;
473 	/*
474 	 * Currently active port and node names for FC devices.
475 	 */
476 	u64 node_name;
477 	u64 port_name;
478 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
479 	struct fc_rport *rport;
480 #endif
481 };
482 
483 struct hv_host_device {
484 	struct hv_device *dev;
485 	unsigned int port;
486 	unsigned char path;
487 	unsigned char target;
488 	struct workqueue_struct *handle_error_wq;
489 	struct work_struct host_scan_work;
490 	struct Scsi_Host *host;
491 };
492 
493 struct storvsc_scan_work {
494 	struct work_struct work;
495 	struct Scsi_Host *host;
496 	u8 lun;
497 	u8 tgt_id;
498 };
499 
500 static void storvsc_device_scan(struct work_struct *work)
501 {
502 	struct storvsc_scan_work *wrk;
503 	struct scsi_device *sdev;
504 
505 	wrk = container_of(work, struct storvsc_scan_work, work);
506 
507 	sdev = scsi_device_lookup(wrk->host, 0, wrk->tgt_id, wrk->lun);
508 	if (!sdev)
509 		goto done;
510 	scsi_rescan_device(&sdev->sdev_gendev);
511 	scsi_device_put(sdev);
512 
513 done:
514 	kfree(wrk);
515 }
516 
517 static void storvsc_host_scan(struct work_struct *work)
518 {
519 	struct Scsi_Host *host;
520 	struct scsi_device *sdev;
521 	struct hv_host_device *host_device =
522 		container_of(work, struct hv_host_device, host_scan_work);
523 
524 	host = host_device->host;
525 	/*
526 	 * Before scanning the host, first check to see if any of the
527 	 * currrently known devices have been hot removed. We issue a
528 	 * "unit ready" command against all currently known devices.
529 	 * This I/O will result in an error for devices that have been
530 	 * removed. As part of handling the I/O error, we remove the device.
531 	 *
532 	 * When a LUN is added or removed, the host sends us a signal to
533 	 * scan the host. Thus we are forced to discover the LUNs that
534 	 * may have been removed this way.
535 	 */
536 	mutex_lock(&host->scan_mutex);
537 	shost_for_each_device(sdev, host)
538 		scsi_test_unit_ready(sdev, 1, 1, NULL);
539 	mutex_unlock(&host->scan_mutex);
540 	/*
541 	 * Now scan the host to discover LUNs that may have been added.
542 	 */
543 	scsi_scan_host(host);
544 }
545 
546 static void storvsc_remove_lun(struct work_struct *work)
547 {
548 	struct storvsc_scan_work *wrk;
549 	struct scsi_device *sdev;
550 
551 	wrk = container_of(work, struct storvsc_scan_work, work);
552 	if (!scsi_host_get(wrk->host))
553 		goto done;
554 
555 	sdev = scsi_device_lookup(wrk->host, 0, wrk->tgt_id, wrk->lun);
556 
557 	if (sdev) {
558 		scsi_remove_device(sdev);
559 		scsi_device_put(sdev);
560 	}
561 	scsi_host_put(wrk->host);
562 
563 done:
564 	kfree(wrk);
565 }
566 
567 
568 /*
569  * We can get incoming messages from the host that are not in response to
570  * messages that we have sent out. An example of this would be messages
571  * received by the guest to notify dynamic addition/removal of LUNs. To
572  * deal with potential race conditions where the driver may be in the
573  * midst of being unloaded when we might receive an unsolicited message
574  * from the host, we have implemented a mechanism to gurantee sequential
575  * consistency:
576  *
577  * 1) Once the device is marked as being destroyed, we will fail all
578  *    outgoing messages.
579  * 2) We permit incoming messages when the device is being destroyed,
580  *    only to properly account for messages already sent out.
581  */
582 
583 static inline struct storvsc_device *get_out_stor_device(
584 					struct hv_device *device)
585 {
586 	struct storvsc_device *stor_device;
587 
588 	stor_device = hv_get_drvdata(device);
589 
590 	if (stor_device && stor_device->destroy)
591 		stor_device = NULL;
592 
593 	return stor_device;
594 }
595 
596 
597 static inline void storvsc_wait_to_drain(struct storvsc_device *dev)
598 {
599 	dev->drain_notify = true;
600 	wait_event(dev->waiting_to_drain,
601 		   atomic_read(&dev->num_outstanding_req) == 0);
602 	dev->drain_notify = false;
603 }
604 
605 static inline struct storvsc_device *get_in_stor_device(
606 					struct hv_device *device)
607 {
608 	struct storvsc_device *stor_device;
609 
610 	stor_device = hv_get_drvdata(device);
611 
612 	if (!stor_device)
613 		goto get_in_err;
614 
615 	/*
616 	 * If the device is being destroyed; allow incoming
617 	 * traffic only to cleanup outstanding requests.
618 	 */
619 
620 	if (stor_device->destroy  &&
621 		(atomic_read(&stor_device->num_outstanding_req) == 0))
622 		stor_device = NULL;
623 
624 get_in_err:
625 	return stor_device;
626 
627 }
628 
629 static void storvsc_change_target_cpu(struct vmbus_channel *channel, u32 old,
630 				      u32 new)
631 {
632 	struct storvsc_device *stor_device;
633 	struct vmbus_channel *cur_chn;
634 	bool old_is_alloced = false;
635 	struct hv_device *device;
636 	unsigned long flags;
637 	int cpu;
638 
639 	device = channel->primary_channel ?
640 			channel->primary_channel->device_obj
641 				: channel->device_obj;
642 	stor_device = get_out_stor_device(device);
643 	if (!stor_device)
644 		return;
645 
646 	/* See storvsc_do_io() -> get_og_chn(). */
647 	spin_lock_irqsave(&stor_device->lock, flags);
648 
649 	/*
650 	 * Determines if the storvsc device has other channels assigned to
651 	 * the "old" CPU to update the alloced_cpus mask and the stor_chns
652 	 * array.
653 	 */
654 	if (device->channel != channel && device->channel->target_cpu == old) {
655 		cur_chn = device->channel;
656 		old_is_alloced = true;
657 		goto old_is_alloced;
658 	}
659 	list_for_each_entry(cur_chn, &device->channel->sc_list, sc_list) {
660 		if (cur_chn == channel)
661 			continue;
662 		if (cur_chn->target_cpu == old) {
663 			old_is_alloced = true;
664 			goto old_is_alloced;
665 		}
666 	}
667 
668 old_is_alloced:
669 	if (old_is_alloced)
670 		WRITE_ONCE(stor_device->stor_chns[old], cur_chn);
671 	else
672 		cpumask_clear_cpu(old, &stor_device->alloced_cpus);
673 
674 	/* "Flush" the stor_chns array. */
675 	for_each_possible_cpu(cpu) {
676 		if (stor_device->stor_chns[cpu] && !cpumask_test_cpu(
677 					cpu, &stor_device->alloced_cpus))
678 			WRITE_ONCE(stor_device->stor_chns[cpu], NULL);
679 	}
680 
681 	WRITE_ONCE(stor_device->stor_chns[new], channel);
682 	cpumask_set_cpu(new, &stor_device->alloced_cpus);
683 
684 	spin_unlock_irqrestore(&stor_device->lock, flags);
685 }
686 
687 static void handle_sc_creation(struct vmbus_channel *new_sc)
688 {
689 	struct hv_device *device = new_sc->primary_channel->device_obj;
690 	struct device *dev = &device->device;
691 	struct storvsc_device *stor_device;
692 	struct vmstorage_channel_properties props;
693 	int ret;
694 
695 	stor_device = get_out_stor_device(device);
696 	if (!stor_device)
697 		return;
698 
699 	memset(&props, 0, sizeof(struct vmstorage_channel_properties));
700 
701 	/*
702 	 * The size of vmbus_requestor is an upper bound on the number of requests
703 	 * that can be in-progress at any one time across all channels.
704 	 */
705 	new_sc->rqstor_size = scsi_driver.can_queue;
706 
707 	ret = vmbus_open(new_sc,
708 			 storvsc_ringbuffer_size,
709 			 storvsc_ringbuffer_size,
710 			 (void *)&props,
711 			 sizeof(struct vmstorage_channel_properties),
712 			 storvsc_on_channel_callback, new_sc);
713 
714 	/* In case vmbus_open() fails, we don't use the sub-channel. */
715 	if (ret != 0) {
716 		dev_err(dev, "Failed to open sub-channel: err=%d\n", ret);
717 		return;
718 	}
719 
720 	new_sc->change_target_cpu_callback = storvsc_change_target_cpu;
721 
722 	/* Add the sub-channel to the array of available channels. */
723 	stor_device->stor_chns[new_sc->target_cpu] = new_sc;
724 	cpumask_set_cpu(new_sc->target_cpu, &stor_device->alloced_cpus);
725 }
726 
727 static void  handle_multichannel_storage(struct hv_device *device, int max_chns)
728 {
729 	struct device *dev = &device->device;
730 	struct storvsc_device *stor_device;
731 	int num_sc;
732 	struct storvsc_cmd_request *request;
733 	struct vstor_packet *vstor_packet;
734 	int ret, t;
735 
736 	/*
737 	 * If the number of CPUs is artificially restricted, such as
738 	 * with maxcpus=1 on the kernel boot line, Hyper-V could offer
739 	 * sub-channels >= the number of CPUs. These sub-channels
740 	 * should not be created. The primary channel is already created
741 	 * and assigned to one CPU, so check against # CPUs - 1.
742 	 */
743 	num_sc = min((int)(num_online_cpus() - 1), max_chns);
744 	if (!num_sc)
745 		return;
746 
747 	stor_device = get_out_stor_device(device);
748 	if (!stor_device)
749 		return;
750 
751 	stor_device->num_sc = num_sc;
752 	request = &stor_device->init_request;
753 	vstor_packet = &request->vstor_packet;
754 
755 	/*
756 	 * Establish a handler for dealing with subchannels.
757 	 */
758 	vmbus_set_sc_create_callback(device->channel, handle_sc_creation);
759 
760 	/*
761 	 * Request the host to create sub-channels.
762 	 */
763 	memset(request, 0, sizeof(struct storvsc_cmd_request));
764 	init_completion(&request->wait_event);
765 	vstor_packet->operation = VSTOR_OPERATION_CREATE_SUB_CHANNELS;
766 	vstor_packet->flags = REQUEST_COMPLETION_FLAG;
767 	vstor_packet->sub_channel_count = num_sc;
768 
769 	ret = vmbus_sendpacket(device->channel, vstor_packet,
770 			       (sizeof(struct vstor_packet) -
771 			       stor_device->vmscsi_size_delta),
772 			       (unsigned long)request,
773 			       VM_PKT_DATA_INBAND,
774 			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
775 
776 	if (ret != 0) {
777 		dev_err(dev, "Failed to create sub-channel: err=%d\n", ret);
778 		return;
779 	}
780 
781 	t = wait_for_completion_timeout(&request->wait_event, 10*HZ);
782 	if (t == 0) {
783 		dev_err(dev, "Failed to create sub-channel: timed out\n");
784 		return;
785 	}
786 
787 	if (vstor_packet->operation != VSTOR_OPERATION_COMPLETE_IO ||
788 	    vstor_packet->status != 0) {
789 		dev_err(dev, "Failed to create sub-channel: op=%d, sts=%d\n",
790 			vstor_packet->operation, vstor_packet->status);
791 		return;
792 	}
793 
794 	/*
795 	 * We need to do nothing here, because vmbus_process_offer()
796 	 * invokes channel->sc_creation_callback, which will open and use
797 	 * the sub-channel(s).
798 	 */
799 }
800 
801 static void cache_wwn(struct storvsc_device *stor_device,
802 		      struct vstor_packet *vstor_packet)
803 {
804 	/*
805 	 * Cache the currently active port and node ww names.
806 	 */
807 	if (vstor_packet->wwn_packet.primary_active) {
808 		stor_device->node_name =
809 			wwn_to_u64(vstor_packet->wwn_packet.primary_node_wwn);
810 		stor_device->port_name =
811 			wwn_to_u64(vstor_packet->wwn_packet.primary_port_wwn);
812 	} else {
813 		stor_device->node_name =
814 			wwn_to_u64(vstor_packet->wwn_packet.secondary_node_wwn);
815 		stor_device->port_name =
816 			wwn_to_u64(vstor_packet->wwn_packet.secondary_port_wwn);
817 	}
818 }
819 
820 
821 static int storvsc_execute_vstor_op(struct hv_device *device,
822 				    struct storvsc_cmd_request *request,
823 				    bool status_check)
824 {
825 	struct storvsc_device *stor_device;
826 	struct vstor_packet *vstor_packet;
827 	int ret, t;
828 
829 	stor_device = get_out_stor_device(device);
830 	if (!stor_device)
831 		return -ENODEV;
832 
833 	vstor_packet = &request->vstor_packet;
834 
835 	init_completion(&request->wait_event);
836 	vstor_packet->flags = REQUEST_COMPLETION_FLAG;
837 
838 	ret = vmbus_sendpacket(device->channel, vstor_packet,
839 			       (sizeof(struct vstor_packet) -
840 			       stor_device->vmscsi_size_delta),
841 			       (unsigned long)request,
842 			       VM_PKT_DATA_INBAND,
843 			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
844 	if (ret != 0)
845 		return ret;
846 
847 	t = wait_for_completion_timeout(&request->wait_event, 5*HZ);
848 	if (t == 0)
849 		return -ETIMEDOUT;
850 
851 	if (!status_check)
852 		return ret;
853 
854 	if (vstor_packet->operation != VSTOR_OPERATION_COMPLETE_IO ||
855 	    vstor_packet->status != 0)
856 		return -EINVAL;
857 
858 	return ret;
859 }
860 
861 static int storvsc_channel_init(struct hv_device *device, bool is_fc)
862 {
863 	struct storvsc_device *stor_device;
864 	struct storvsc_cmd_request *request;
865 	struct vstor_packet *vstor_packet;
866 	int ret, i;
867 	int max_chns;
868 	bool process_sub_channels = false;
869 
870 	stor_device = get_out_stor_device(device);
871 	if (!stor_device)
872 		return -ENODEV;
873 
874 	request = &stor_device->init_request;
875 	vstor_packet = &request->vstor_packet;
876 
877 	/*
878 	 * Now, initiate the vsc/vsp initialization protocol on the open
879 	 * channel
880 	 */
881 	memset(request, 0, sizeof(struct storvsc_cmd_request));
882 	vstor_packet->operation = VSTOR_OPERATION_BEGIN_INITIALIZATION;
883 	ret = storvsc_execute_vstor_op(device, request, true);
884 	if (ret)
885 		return ret;
886 	/*
887 	 * Query host supported protocol version.
888 	 */
889 
890 	for (i = 0; i < ARRAY_SIZE(vmstor_protocols); i++) {
891 		/* reuse the packet for version range supported */
892 		memset(vstor_packet, 0, sizeof(struct vstor_packet));
893 		vstor_packet->operation =
894 			VSTOR_OPERATION_QUERY_PROTOCOL_VERSION;
895 
896 		vstor_packet->version.major_minor =
897 			vmstor_protocols[i].protocol_version;
898 
899 		/*
900 		 * The revision number is only used in Windows; set it to 0.
901 		 */
902 		vstor_packet->version.revision = 0;
903 		ret = storvsc_execute_vstor_op(device, request, false);
904 		if (ret != 0)
905 			return ret;
906 
907 		if (vstor_packet->operation != VSTOR_OPERATION_COMPLETE_IO)
908 			return -EINVAL;
909 
910 		if (vstor_packet->status == 0) {
911 			vmstor_proto_version =
912 				vmstor_protocols[i].protocol_version;
913 
914 			sense_buffer_size =
915 				vmstor_protocols[i].sense_buffer_size;
916 
917 			stor_device->vmscsi_size_delta =
918 				vmstor_protocols[i].vmscsi_size_delta;
919 
920 			break;
921 		}
922 	}
923 
924 	if (vstor_packet->status != 0)
925 		return -EINVAL;
926 
927 
928 	memset(vstor_packet, 0, sizeof(struct vstor_packet));
929 	vstor_packet->operation = VSTOR_OPERATION_QUERY_PROPERTIES;
930 	ret = storvsc_execute_vstor_op(device, request, true);
931 	if (ret != 0)
932 		return ret;
933 
934 	/*
935 	 * Check to see if multi-channel support is there.
936 	 * Hosts that implement protocol version of 5.1 and above
937 	 * support multi-channel.
938 	 */
939 	max_chns = vstor_packet->storage_channel_properties.max_channel_cnt;
940 
941 	/*
942 	 * Allocate state to manage the sub-channels.
943 	 * We allocate an array based on the numbers of possible CPUs
944 	 * (Hyper-V does not support cpu online/offline).
945 	 * This Array will be sparseley populated with unique
946 	 * channels - primary + sub-channels.
947 	 * We will however populate all the slots to evenly distribute
948 	 * the load.
949 	 */
950 	stor_device->stor_chns = kcalloc(num_possible_cpus(), sizeof(void *),
951 					 GFP_KERNEL);
952 	if (stor_device->stor_chns == NULL)
953 		return -ENOMEM;
954 
955 	device->channel->change_target_cpu_callback = storvsc_change_target_cpu;
956 
957 	stor_device->stor_chns[device->channel->target_cpu] = device->channel;
958 	cpumask_set_cpu(device->channel->target_cpu,
959 			&stor_device->alloced_cpus);
960 
961 	if (vmstor_proto_version >= VMSTOR_PROTO_VERSION_WIN8) {
962 		if (vstor_packet->storage_channel_properties.flags &
963 		    STORAGE_CHANNEL_SUPPORTS_MULTI_CHANNEL)
964 			process_sub_channels = true;
965 	}
966 	stor_device->max_transfer_bytes =
967 		vstor_packet->storage_channel_properties.max_transfer_bytes;
968 
969 	if (!is_fc)
970 		goto done;
971 
972 	/*
973 	 * For FC devices retrieve FC HBA data.
974 	 */
975 	memset(vstor_packet, 0, sizeof(struct vstor_packet));
976 	vstor_packet->operation = VSTOR_OPERATION_FCHBA_DATA;
977 	ret = storvsc_execute_vstor_op(device, request, true);
978 	if (ret != 0)
979 		return ret;
980 
981 	/*
982 	 * Cache the currently active port and node ww names.
983 	 */
984 	cache_wwn(stor_device, vstor_packet);
985 
986 done:
987 
988 	memset(vstor_packet, 0, sizeof(struct vstor_packet));
989 	vstor_packet->operation = VSTOR_OPERATION_END_INITIALIZATION;
990 	ret = storvsc_execute_vstor_op(device, request, true);
991 	if (ret != 0)
992 		return ret;
993 
994 	if (process_sub_channels)
995 		handle_multichannel_storage(device, max_chns);
996 
997 	return ret;
998 }
999 
1000 static void storvsc_handle_error(struct vmscsi_request *vm_srb,
1001 				struct scsi_cmnd *scmnd,
1002 				struct Scsi_Host *host,
1003 				u8 asc, u8 ascq)
1004 {
1005 	struct storvsc_scan_work *wrk;
1006 	void (*process_err_fn)(struct work_struct *work);
1007 	struct hv_host_device *host_dev = shost_priv(host);
1008 	bool do_work = false;
1009 
1010 	switch (SRB_STATUS(vm_srb->srb_status)) {
1011 	case SRB_STATUS_ERROR:
1012 		/*
1013 		 * Let upper layer deal with error when
1014 		 * sense message is present.
1015 		 */
1016 
1017 		if (vm_srb->srb_status & SRB_STATUS_AUTOSENSE_VALID)
1018 			break;
1019 		/*
1020 		 * If there is an error; offline the device since all
1021 		 * error recovery strategies would have already been
1022 		 * deployed on the host side. However, if the command
1023 		 * were a pass-through command deal with it appropriately.
1024 		 */
1025 		switch (scmnd->cmnd[0]) {
1026 		case ATA_16:
1027 		case ATA_12:
1028 			set_host_byte(scmnd, DID_PASSTHROUGH);
1029 			break;
1030 		/*
1031 		 * On Some Windows hosts TEST_UNIT_READY command can return
1032 		 * SRB_STATUS_ERROR, let the upper level code deal with it
1033 		 * based on the sense information.
1034 		 */
1035 		case TEST_UNIT_READY:
1036 			break;
1037 		default:
1038 			set_host_byte(scmnd, DID_ERROR);
1039 		}
1040 		break;
1041 	case SRB_STATUS_INVALID_LUN:
1042 		set_host_byte(scmnd, DID_NO_CONNECT);
1043 		do_work = true;
1044 		process_err_fn = storvsc_remove_lun;
1045 		break;
1046 	case SRB_STATUS_ABORTED:
1047 		if (vm_srb->srb_status & SRB_STATUS_AUTOSENSE_VALID &&
1048 		    (asc == 0x2a) && (ascq == 0x9)) {
1049 			do_work = true;
1050 			process_err_fn = storvsc_device_scan;
1051 			/*
1052 			 * Retry the I/O that triggered this.
1053 			 */
1054 			set_host_byte(scmnd, DID_REQUEUE);
1055 		}
1056 		break;
1057 	}
1058 
1059 	if (!do_work)
1060 		return;
1061 
1062 	/*
1063 	 * We need to schedule work to process this error; schedule it.
1064 	 */
1065 	wrk = kmalloc(sizeof(struct storvsc_scan_work), GFP_ATOMIC);
1066 	if (!wrk) {
1067 		set_host_byte(scmnd, DID_TARGET_FAILURE);
1068 		return;
1069 	}
1070 
1071 	wrk->host = host;
1072 	wrk->lun = vm_srb->lun;
1073 	wrk->tgt_id = vm_srb->target_id;
1074 	INIT_WORK(&wrk->work, process_err_fn);
1075 	queue_work(host_dev->handle_error_wq, &wrk->work);
1076 }
1077 
1078 
1079 static void storvsc_command_completion(struct storvsc_cmd_request *cmd_request,
1080 				       struct storvsc_device *stor_dev)
1081 {
1082 	struct scsi_cmnd *scmnd = cmd_request->cmd;
1083 	struct scsi_sense_hdr sense_hdr;
1084 	struct vmscsi_request *vm_srb;
1085 	u32 data_transfer_length;
1086 	struct Scsi_Host *host;
1087 	u32 payload_sz = cmd_request->payload_sz;
1088 	void *payload = cmd_request->payload;
1089 
1090 	host = stor_dev->host;
1091 
1092 	vm_srb = &cmd_request->vstor_packet.vm_srb;
1093 	data_transfer_length = vm_srb->data_transfer_length;
1094 
1095 	scmnd->result = vm_srb->scsi_status;
1096 
1097 	if (scmnd->result) {
1098 		if (scsi_normalize_sense(scmnd->sense_buffer,
1099 				SCSI_SENSE_BUFFERSIZE, &sense_hdr) &&
1100 		    !(sense_hdr.sense_key == NOT_READY &&
1101 				 sense_hdr.asc == 0x03A) &&
1102 		    do_logging(STORVSC_LOGGING_ERROR))
1103 			scsi_print_sense_hdr(scmnd->device, "storvsc",
1104 					     &sense_hdr);
1105 	}
1106 
1107 	if (vm_srb->srb_status != SRB_STATUS_SUCCESS) {
1108 		storvsc_handle_error(vm_srb, scmnd, host, sense_hdr.asc,
1109 					 sense_hdr.ascq);
1110 		/*
1111 		 * The Windows driver set data_transfer_length on
1112 		 * SRB_STATUS_DATA_OVERRUN. On other errors, this value
1113 		 * is untouched.  In these cases we set it to 0.
1114 		 */
1115 		if (vm_srb->srb_status != SRB_STATUS_DATA_OVERRUN)
1116 			data_transfer_length = 0;
1117 	}
1118 
1119 	/* Validate data_transfer_length (from Hyper-V) */
1120 	if (data_transfer_length > cmd_request->payload->range.len)
1121 		data_transfer_length = cmd_request->payload->range.len;
1122 
1123 	scsi_set_resid(scmnd,
1124 		cmd_request->payload->range.len - data_transfer_length);
1125 
1126 	scmnd->scsi_done(scmnd);
1127 
1128 	if (payload_sz >
1129 		sizeof(struct vmbus_channel_packet_multipage_buffer))
1130 		kfree(payload);
1131 }
1132 
1133 static void storvsc_on_io_completion(struct storvsc_device *stor_device,
1134 				  struct vstor_packet *vstor_packet,
1135 				  struct storvsc_cmd_request *request)
1136 {
1137 	struct vstor_packet *stor_pkt;
1138 	struct hv_device *device = stor_device->device;
1139 
1140 	stor_pkt = &request->vstor_packet;
1141 
1142 	/*
1143 	 * The current SCSI handling on the host side does
1144 	 * not correctly handle:
1145 	 * INQUIRY command with page code parameter set to 0x80
1146 	 * MODE_SENSE command with cmd[2] == 0x1c
1147 	 *
1148 	 * Setup srb and scsi status so this won't be fatal.
1149 	 * We do this so we can distinguish truly fatal failues
1150 	 * (srb status == 0x4) and off-line the device in that case.
1151 	 */
1152 
1153 	if ((stor_pkt->vm_srb.cdb[0] == INQUIRY) ||
1154 	   (stor_pkt->vm_srb.cdb[0] == MODE_SENSE)) {
1155 		vstor_packet->vm_srb.scsi_status = 0;
1156 		vstor_packet->vm_srb.srb_status = SRB_STATUS_SUCCESS;
1157 	}
1158 
1159 
1160 	/* Copy over the status...etc */
1161 	stor_pkt->vm_srb.scsi_status = vstor_packet->vm_srb.scsi_status;
1162 	stor_pkt->vm_srb.srb_status = vstor_packet->vm_srb.srb_status;
1163 
1164 	/* Validate sense_info_length (from Hyper-V) */
1165 	if (vstor_packet->vm_srb.sense_info_length > sense_buffer_size)
1166 		vstor_packet->vm_srb.sense_info_length = sense_buffer_size;
1167 
1168 	stor_pkt->vm_srb.sense_info_length =
1169 	vstor_packet->vm_srb.sense_info_length;
1170 
1171 	if (vstor_packet->vm_srb.scsi_status != 0 ||
1172 	    vstor_packet->vm_srb.srb_status != SRB_STATUS_SUCCESS)
1173 		storvsc_log(device, STORVSC_LOGGING_WARN,
1174 			"cmd 0x%x scsi status 0x%x srb status 0x%x\n",
1175 			stor_pkt->vm_srb.cdb[0],
1176 			vstor_packet->vm_srb.scsi_status,
1177 			vstor_packet->vm_srb.srb_status);
1178 
1179 	if ((vstor_packet->vm_srb.scsi_status & 0xFF) == 0x02) {
1180 		/* CHECK_CONDITION */
1181 		if (vstor_packet->vm_srb.srb_status &
1182 			SRB_STATUS_AUTOSENSE_VALID) {
1183 			/* autosense data available */
1184 
1185 			storvsc_log(device, STORVSC_LOGGING_WARN,
1186 				"stor pkt %p autosense data valid - len %d\n",
1187 				request, vstor_packet->vm_srb.sense_info_length);
1188 
1189 			memcpy(request->cmd->sense_buffer,
1190 			       vstor_packet->vm_srb.sense_data,
1191 			       vstor_packet->vm_srb.sense_info_length);
1192 
1193 		}
1194 	}
1195 
1196 	stor_pkt->vm_srb.data_transfer_length =
1197 	vstor_packet->vm_srb.data_transfer_length;
1198 
1199 	storvsc_command_completion(request, stor_device);
1200 
1201 	if (atomic_dec_and_test(&stor_device->num_outstanding_req) &&
1202 		stor_device->drain_notify)
1203 		wake_up(&stor_device->waiting_to_drain);
1204 
1205 
1206 }
1207 
1208 static void storvsc_on_receive(struct storvsc_device *stor_device,
1209 			     struct vstor_packet *vstor_packet,
1210 			     struct storvsc_cmd_request *request)
1211 {
1212 	struct hv_host_device *host_dev;
1213 	switch (vstor_packet->operation) {
1214 	case VSTOR_OPERATION_COMPLETE_IO:
1215 		storvsc_on_io_completion(stor_device, vstor_packet, request);
1216 		break;
1217 
1218 	case VSTOR_OPERATION_REMOVE_DEVICE:
1219 	case VSTOR_OPERATION_ENUMERATE_BUS:
1220 		host_dev = shost_priv(stor_device->host);
1221 		queue_work(
1222 			host_dev->handle_error_wq, &host_dev->host_scan_work);
1223 		break;
1224 
1225 	case VSTOR_OPERATION_FCHBA_DATA:
1226 		cache_wwn(stor_device, vstor_packet);
1227 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
1228 		fc_host_node_name(stor_device->host) = stor_device->node_name;
1229 		fc_host_port_name(stor_device->host) = stor_device->port_name;
1230 #endif
1231 		break;
1232 	default:
1233 		break;
1234 	}
1235 }
1236 
1237 static void storvsc_on_channel_callback(void *context)
1238 {
1239 	struct vmbus_channel *channel = (struct vmbus_channel *)context;
1240 	const struct vmpacket_descriptor *desc;
1241 	struct hv_device *device;
1242 	struct storvsc_device *stor_device;
1243 
1244 	if (channel->primary_channel != NULL)
1245 		device = channel->primary_channel->device_obj;
1246 	else
1247 		device = channel->device_obj;
1248 
1249 	stor_device = get_in_stor_device(device);
1250 	if (!stor_device)
1251 		return;
1252 
1253 	foreach_vmbus_pkt(desc, channel) {
1254 		void *packet = hv_pkt_data(desc);
1255 		struct storvsc_cmd_request *request;
1256 		u64 cmd_rqst;
1257 
1258 		cmd_rqst = vmbus_request_addr(&channel->requestor,
1259 					      desc->trans_id);
1260 		if (cmd_rqst == VMBUS_RQST_ERROR) {
1261 			dev_err(&device->device,
1262 				"Incorrect transaction id\n");
1263 			continue;
1264 		}
1265 
1266 		request = (struct storvsc_cmd_request *)(unsigned long)cmd_rqst;
1267 
1268 		if (hv_pkt_datalen(desc) < sizeof(struct vstor_packet) -
1269 				stor_device->vmscsi_size_delta) {
1270 			dev_err(&device->device, "Invalid packet len\n");
1271 			continue;
1272 		}
1273 
1274 		if (request == &stor_device->init_request ||
1275 		    request == &stor_device->reset_request) {
1276 			memcpy(&request->vstor_packet, packet,
1277 			       (sizeof(struct vstor_packet) - stor_device->vmscsi_size_delta));
1278 			complete(&request->wait_event);
1279 		} else {
1280 			storvsc_on_receive(stor_device, packet, request);
1281 		}
1282 	}
1283 }
1284 
1285 static int storvsc_connect_to_vsp(struct hv_device *device, u32 ring_size,
1286 				  bool is_fc)
1287 {
1288 	struct vmstorage_channel_properties props;
1289 	int ret;
1290 
1291 	memset(&props, 0, sizeof(struct vmstorage_channel_properties));
1292 
1293 	/*
1294 	 * The size of vmbus_requestor is an upper bound on the number of requests
1295 	 * that can be in-progress at any one time across all channels.
1296 	 */
1297 	device->channel->rqstor_size = scsi_driver.can_queue;
1298 
1299 	ret = vmbus_open(device->channel,
1300 			 ring_size,
1301 			 ring_size,
1302 			 (void *)&props,
1303 			 sizeof(struct vmstorage_channel_properties),
1304 			 storvsc_on_channel_callback, device->channel);
1305 
1306 	if (ret != 0)
1307 		return ret;
1308 
1309 	ret = storvsc_channel_init(device, is_fc);
1310 
1311 	return ret;
1312 }
1313 
1314 static int storvsc_dev_remove(struct hv_device *device)
1315 {
1316 	struct storvsc_device *stor_device;
1317 
1318 	stor_device = hv_get_drvdata(device);
1319 
1320 	stor_device->destroy = true;
1321 
1322 	/* Make sure flag is set before waiting */
1323 	wmb();
1324 
1325 	/*
1326 	 * At this point, all outbound traffic should be disable. We
1327 	 * only allow inbound traffic (responses) to proceed so that
1328 	 * outstanding requests can be completed.
1329 	 */
1330 
1331 	storvsc_wait_to_drain(stor_device);
1332 
1333 	/*
1334 	 * Since we have already drained, we don't need to busy wait
1335 	 * as was done in final_release_stor_device()
1336 	 * Note that we cannot set the ext pointer to NULL until
1337 	 * we have drained - to drain the outgoing packets, we need to
1338 	 * allow incoming packets.
1339 	 */
1340 	hv_set_drvdata(device, NULL);
1341 
1342 	/* Close the channel */
1343 	vmbus_close(device->channel);
1344 
1345 	kfree(stor_device->stor_chns);
1346 	kfree(stor_device);
1347 	return 0;
1348 }
1349 
1350 static struct vmbus_channel *get_og_chn(struct storvsc_device *stor_device,
1351 					u16 q_num)
1352 {
1353 	u16 slot = 0;
1354 	u16 hash_qnum;
1355 	const struct cpumask *node_mask;
1356 	int num_channels, tgt_cpu;
1357 
1358 	if (stor_device->num_sc == 0) {
1359 		stor_device->stor_chns[q_num] = stor_device->device->channel;
1360 		return stor_device->device->channel;
1361 	}
1362 
1363 	/*
1364 	 * Our channel array is sparsley populated and we
1365 	 * initiated I/O on a processor/hw-q that does not
1366 	 * currently have a designated channel. Fix this.
1367 	 * The strategy is simple:
1368 	 * I. Ensure NUMA locality
1369 	 * II. Distribute evenly (best effort)
1370 	 */
1371 
1372 	node_mask = cpumask_of_node(cpu_to_node(q_num));
1373 
1374 	num_channels = 0;
1375 	for_each_cpu(tgt_cpu, &stor_device->alloced_cpus) {
1376 		if (cpumask_test_cpu(tgt_cpu, node_mask))
1377 			num_channels++;
1378 	}
1379 	if (num_channels == 0) {
1380 		stor_device->stor_chns[q_num] = stor_device->device->channel;
1381 		return stor_device->device->channel;
1382 	}
1383 
1384 	hash_qnum = q_num;
1385 	while (hash_qnum >= num_channels)
1386 		hash_qnum -= num_channels;
1387 
1388 	for_each_cpu(tgt_cpu, &stor_device->alloced_cpus) {
1389 		if (!cpumask_test_cpu(tgt_cpu, node_mask))
1390 			continue;
1391 		if (slot == hash_qnum)
1392 			break;
1393 		slot++;
1394 	}
1395 
1396 	stor_device->stor_chns[q_num] = stor_device->stor_chns[tgt_cpu];
1397 
1398 	return stor_device->stor_chns[q_num];
1399 }
1400 
1401 
1402 static int storvsc_do_io(struct hv_device *device,
1403 			 struct storvsc_cmd_request *request, u16 q_num)
1404 {
1405 	struct storvsc_device *stor_device;
1406 	struct vstor_packet *vstor_packet;
1407 	struct vmbus_channel *outgoing_channel, *channel;
1408 	unsigned long flags;
1409 	int ret = 0;
1410 	const struct cpumask *node_mask;
1411 	int tgt_cpu;
1412 
1413 	vstor_packet = &request->vstor_packet;
1414 	stor_device = get_out_stor_device(device);
1415 
1416 	if (!stor_device)
1417 		return -ENODEV;
1418 
1419 
1420 	request->device  = device;
1421 	/*
1422 	 * Select an appropriate channel to send the request out.
1423 	 */
1424 	/* See storvsc_change_target_cpu(). */
1425 	outgoing_channel = READ_ONCE(stor_device->stor_chns[q_num]);
1426 	if (outgoing_channel != NULL) {
1427 		if (outgoing_channel->target_cpu == q_num) {
1428 			/*
1429 			 * Ideally, we want to pick a different channel if
1430 			 * available on the same NUMA node.
1431 			 */
1432 			node_mask = cpumask_of_node(cpu_to_node(q_num));
1433 			for_each_cpu_wrap(tgt_cpu,
1434 				 &stor_device->alloced_cpus, q_num + 1) {
1435 				if (!cpumask_test_cpu(tgt_cpu, node_mask))
1436 					continue;
1437 				if (tgt_cpu == q_num)
1438 					continue;
1439 				channel = READ_ONCE(
1440 					stor_device->stor_chns[tgt_cpu]);
1441 				if (channel == NULL)
1442 					continue;
1443 				if (hv_get_avail_to_write_percent(
1444 							&channel->outbound)
1445 						> ring_avail_percent_lowater) {
1446 					outgoing_channel = channel;
1447 					goto found_channel;
1448 				}
1449 			}
1450 
1451 			/*
1452 			 * All the other channels on the same NUMA node are
1453 			 * busy. Try to use the channel on the current CPU
1454 			 */
1455 			if (hv_get_avail_to_write_percent(
1456 						&outgoing_channel->outbound)
1457 					> ring_avail_percent_lowater)
1458 				goto found_channel;
1459 
1460 			/*
1461 			 * If we reach here, all the channels on the current
1462 			 * NUMA node are busy. Try to find a channel in
1463 			 * other NUMA nodes
1464 			 */
1465 			for_each_cpu(tgt_cpu, &stor_device->alloced_cpus) {
1466 				if (cpumask_test_cpu(tgt_cpu, node_mask))
1467 					continue;
1468 				channel = READ_ONCE(
1469 					stor_device->stor_chns[tgt_cpu]);
1470 				if (channel == NULL)
1471 					continue;
1472 				if (hv_get_avail_to_write_percent(
1473 							&channel->outbound)
1474 						> ring_avail_percent_lowater) {
1475 					outgoing_channel = channel;
1476 					goto found_channel;
1477 				}
1478 			}
1479 		}
1480 	} else {
1481 		spin_lock_irqsave(&stor_device->lock, flags);
1482 		outgoing_channel = stor_device->stor_chns[q_num];
1483 		if (outgoing_channel != NULL) {
1484 			spin_unlock_irqrestore(&stor_device->lock, flags);
1485 			goto found_channel;
1486 		}
1487 		outgoing_channel = get_og_chn(stor_device, q_num);
1488 		spin_unlock_irqrestore(&stor_device->lock, flags);
1489 	}
1490 
1491 found_channel:
1492 	vstor_packet->flags |= REQUEST_COMPLETION_FLAG;
1493 
1494 	vstor_packet->vm_srb.length = (sizeof(struct vmscsi_request) -
1495 					stor_device->vmscsi_size_delta);
1496 
1497 
1498 	vstor_packet->vm_srb.sense_info_length = sense_buffer_size;
1499 
1500 
1501 	vstor_packet->vm_srb.data_transfer_length =
1502 	request->payload->range.len;
1503 
1504 	vstor_packet->operation = VSTOR_OPERATION_EXECUTE_SRB;
1505 
1506 	if (request->payload->range.len) {
1507 
1508 		ret = vmbus_sendpacket_mpb_desc(outgoing_channel,
1509 				request->payload, request->payload_sz,
1510 				vstor_packet,
1511 				(sizeof(struct vstor_packet) -
1512 				stor_device->vmscsi_size_delta),
1513 				(unsigned long)request);
1514 	} else {
1515 		ret = vmbus_sendpacket(outgoing_channel, vstor_packet,
1516 			       (sizeof(struct vstor_packet) -
1517 				stor_device->vmscsi_size_delta),
1518 			       (unsigned long)request,
1519 			       VM_PKT_DATA_INBAND,
1520 			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
1521 	}
1522 
1523 	if (ret != 0)
1524 		return ret;
1525 
1526 	atomic_inc(&stor_device->num_outstanding_req);
1527 
1528 	return ret;
1529 }
1530 
1531 static int storvsc_device_alloc(struct scsi_device *sdevice)
1532 {
1533 	/*
1534 	 * Set blist flag to permit the reading of the VPD pages even when
1535 	 * the target may claim SPC-2 compliance. MSFT targets currently
1536 	 * claim SPC-2 compliance while they implement post SPC-2 features.
1537 	 * With this flag we can correctly handle WRITE_SAME_16 issues.
1538 	 *
1539 	 * Hypervisor reports SCSI_UNKNOWN type for DVD ROM device but
1540 	 * still supports REPORT LUN.
1541 	 */
1542 	sdevice->sdev_bflags = BLIST_REPORTLUN2 | BLIST_TRY_VPD_PAGES;
1543 
1544 	return 0;
1545 }
1546 
1547 static int storvsc_device_configure(struct scsi_device *sdevice)
1548 {
1549 	blk_queue_rq_timeout(sdevice->request_queue, (storvsc_timeout * HZ));
1550 
1551 	sdevice->no_write_same = 1;
1552 
1553 	/*
1554 	 * If the host is WIN8 or WIN8 R2, claim conformance to SPC-3
1555 	 * if the device is a MSFT virtual device.  If the host is
1556 	 * WIN10 or newer, allow write_same.
1557 	 */
1558 	if (!strncmp(sdevice->vendor, "Msft", 4)) {
1559 		switch (vmstor_proto_version) {
1560 		case VMSTOR_PROTO_VERSION_WIN8:
1561 		case VMSTOR_PROTO_VERSION_WIN8_1:
1562 			sdevice->scsi_level = SCSI_SPC_3;
1563 			break;
1564 		}
1565 
1566 		if (vmstor_proto_version >= VMSTOR_PROTO_VERSION_WIN10)
1567 			sdevice->no_write_same = 0;
1568 	}
1569 
1570 	return 0;
1571 }
1572 
1573 static int storvsc_get_chs(struct scsi_device *sdev, struct block_device * bdev,
1574 			   sector_t capacity, int *info)
1575 {
1576 	sector_t nsect = capacity;
1577 	sector_t cylinders = nsect;
1578 	int heads, sectors_pt;
1579 
1580 	/*
1581 	 * We are making up these values; let us keep it simple.
1582 	 */
1583 	heads = 0xff;
1584 	sectors_pt = 0x3f;      /* Sectors per track */
1585 	sector_div(cylinders, heads * sectors_pt);
1586 	if ((sector_t)(cylinders + 1) * heads * sectors_pt < nsect)
1587 		cylinders = 0xffff;
1588 
1589 	info[0] = heads;
1590 	info[1] = sectors_pt;
1591 	info[2] = (int)cylinders;
1592 
1593 	return 0;
1594 }
1595 
1596 static int storvsc_host_reset_handler(struct scsi_cmnd *scmnd)
1597 {
1598 	struct hv_host_device *host_dev = shost_priv(scmnd->device->host);
1599 	struct hv_device *device = host_dev->dev;
1600 
1601 	struct storvsc_device *stor_device;
1602 	struct storvsc_cmd_request *request;
1603 	struct vstor_packet *vstor_packet;
1604 	int ret, t;
1605 
1606 	stor_device = get_out_stor_device(device);
1607 	if (!stor_device)
1608 		return FAILED;
1609 
1610 	request = &stor_device->reset_request;
1611 	vstor_packet = &request->vstor_packet;
1612 	memset(vstor_packet, 0, sizeof(struct vstor_packet));
1613 
1614 	init_completion(&request->wait_event);
1615 
1616 	vstor_packet->operation = VSTOR_OPERATION_RESET_BUS;
1617 	vstor_packet->flags = REQUEST_COMPLETION_FLAG;
1618 	vstor_packet->vm_srb.path_id = stor_device->path_id;
1619 
1620 	ret = vmbus_sendpacket(device->channel, vstor_packet,
1621 			       (sizeof(struct vstor_packet) -
1622 				stor_device->vmscsi_size_delta),
1623 			       (unsigned long)&stor_device->reset_request,
1624 			       VM_PKT_DATA_INBAND,
1625 			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
1626 	if (ret != 0)
1627 		return FAILED;
1628 
1629 	t = wait_for_completion_timeout(&request->wait_event, 5*HZ);
1630 	if (t == 0)
1631 		return TIMEOUT_ERROR;
1632 
1633 
1634 	/*
1635 	 * At this point, all outstanding requests in the adapter
1636 	 * should have been flushed out and return to us
1637 	 * There is a potential race here where the host may be in
1638 	 * the process of responding when we return from here.
1639 	 * Just wait for all in-transit packets to be accounted for
1640 	 * before we return from here.
1641 	 */
1642 	storvsc_wait_to_drain(stor_device);
1643 
1644 	return SUCCESS;
1645 }
1646 
1647 /*
1648  * The host guarantees to respond to each command, although I/O latencies might
1649  * be unbounded on Azure.  Reset the timer unconditionally to give the host a
1650  * chance to perform EH.
1651  */
1652 static enum blk_eh_timer_return storvsc_eh_timed_out(struct scsi_cmnd *scmnd)
1653 {
1654 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
1655 	if (scmnd->device->host->transportt == fc_transport_template)
1656 		return fc_eh_timed_out(scmnd);
1657 #endif
1658 	return BLK_EH_RESET_TIMER;
1659 }
1660 
1661 static bool storvsc_scsi_cmd_ok(struct scsi_cmnd *scmnd)
1662 {
1663 	bool allowed = true;
1664 	u8 scsi_op = scmnd->cmnd[0];
1665 
1666 	switch (scsi_op) {
1667 	/* the host does not handle WRITE_SAME, log accident usage */
1668 	case WRITE_SAME:
1669 	/*
1670 	 * smartd sends this command and the host does not handle
1671 	 * this. So, don't send it.
1672 	 */
1673 	case SET_WINDOW:
1674 		scmnd->result = DID_ERROR << 16;
1675 		allowed = false;
1676 		break;
1677 	default:
1678 		break;
1679 	}
1680 	return allowed;
1681 }
1682 
1683 static int storvsc_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *scmnd)
1684 {
1685 	int ret;
1686 	struct hv_host_device *host_dev = shost_priv(host);
1687 	struct hv_device *dev = host_dev->dev;
1688 	struct storvsc_cmd_request *cmd_request = scsi_cmd_priv(scmnd);
1689 	int i;
1690 	struct scatterlist *sgl;
1691 	unsigned int sg_count = 0;
1692 	struct vmscsi_request *vm_srb;
1693 	struct scatterlist *cur_sgl;
1694 	struct vmbus_packet_mpb_array  *payload;
1695 	u32 payload_sz;
1696 	u32 length;
1697 
1698 	if (vmstor_proto_version <= VMSTOR_PROTO_VERSION_WIN8) {
1699 		/*
1700 		 * On legacy hosts filter unimplemented commands.
1701 		 * Future hosts are expected to correctly handle
1702 		 * unsupported commands. Furthermore, it is
1703 		 * possible that some of the currently
1704 		 * unsupported commands maybe supported in
1705 		 * future versions of the host.
1706 		 */
1707 		if (!storvsc_scsi_cmd_ok(scmnd)) {
1708 			scmnd->scsi_done(scmnd);
1709 			return 0;
1710 		}
1711 	}
1712 
1713 	/* Setup the cmd request */
1714 	cmd_request->cmd = scmnd;
1715 
1716 	memset(&cmd_request->vstor_packet, 0, sizeof(struct vstor_packet));
1717 	vm_srb = &cmd_request->vstor_packet.vm_srb;
1718 	vm_srb->win8_extension.time_out_value = 60;
1719 
1720 	vm_srb->win8_extension.srb_flags |=
1721 		SRB_FLAGS_DISABLE_SYNCH_TRANSFER;
1722 
1723 	if (scmnd->device->tagged_supported) {
1724 		vm_srb->win8_extension.srb_flags |=
1725 		(SRB_FLAGS_QUEUE_ACTION_ENABLE | SRB_FLAGS_NO_QUEUE_FREEZE);
1726 		vm_srb->win8_extension.queue_tag = SP_UNTAGGED;
1727 		vm_srb->win8_extension.queue_action = SRB_SIMPLE_TAG_REQUEST;
1728 	}
1729 
1730 	/* Build the SRB */
1731 	switch (scmnd->sc_data_direction) {
1732 	case DMA_TO_DEVICE:
1733 		vm_srb->data_in = WRITE_TYPE;
1734 		vm_srb->win8_extension.srb_flags |= SRB_FLAGS_DATA_OUT;
1735 		break;
1736 	case DMA_FROM_DEVICE:
1737 		vm_srb->data_in = READ_TYPE;
1738 		vm_srb->win8_extension.srb_flags |= SRB_FLAGS_DATA_IN;
1739 		break;
1740 	case DMA_NONE:
1741 		vm_srb->data_in = UNKNOWN_TYPE;
1742 		vm_srb->win8_extension.srb_flags |= SRB_FLAGS_NO_DATA_TRANSFER;
1743 		break;
1744 	default:
1745 		/*
1746 		 * This is DMA_BIDIRECTIONAL or something else we are never
1747 		 * supposed to see here.
1748 		 */
1749 		WARN(1, "Unexpected data direction: %d\n",
1750 		     scmnd->sc_data_direction);
1751 		return -EINVAL;
1752 	}
1753 
1754 
1755 	vm_srb->port_number = host_dev->port;
1756 	vm_srb->path_id = scmnd->device->channel;
1757 	vm_srb->target_id = scmnd->device->id;
1758 	vm_srb->lun = scmnd->device->lun;
1759 
1760 	vm_srb->cdb_length = scmnd->cmd_len;
1761 
1762 	memcpy(vm_srb->cdb, scmnd->cmnd, vm_srb->cdb_length);
1763 
1764 	sgl = (struct scatterlist *)scsi_sglist(scmnd);
1765 	sg_count = scsi_sg_count(scmnd);
1766 
1767 	length = scsi_bufflen(scmnd);
1768 	payload = (struct vmbus_packet_mpb_array *)&cmd_request->mpb;
1769 	payload_sz = sizeof(cmd_request->mpb);
1770 
1771 	if (sg_count) {
1772 		unsigned int hvpgoff = 0;
1773 		unsigned long offset_in_hvpg = sgl->offset & ~HV_HYP_PAGE_MASK;
1774 		unsigned int hvpg_count = HVPFN_UP(offset_in_hvpg + length);
1775 		u64 hvpfn;
1776 
1777 		if (hvpg_count > MAX_PAGE_BUFFER_COUNT) {
1778 
1779 			payload_sz = (hvpg_count * sizeof(u64) +
1780 				      sizeof(struct vmbus_packet_mpb_array));
1781 			payload = kzalloc(payload_sz, GFP_ATOMIC);
1782 			if (!payload)
1783 				return SCSI_MLQUEUE_DEVICE_BUSY;
1784 		}
1785 
1786 		/*
1787 		 * sgl is a list of PAGEs, and payload->range.pfn_array
1788 		 * expects the page number in the unit of HV_HYP_PAGE_SIZE (the
1789 		 * page size that Hyper-V uses, so here we need to divide PAGEs
1790 		 * into HV_HYP_PAGE in case that PAGE_SIZE > HV_HYP_PAGE_SIZE.
1791 		 * Besides, payload->range.offset should be the offset in one
1792 		 * HV_HYP_PAGE.
1793 		 */
1794 		payload->range.len = length;
1795 		payload->range.offset = offset_in_hvpg;
1796 		hvpgoff = sgl->offset >> HV_HYP_PAGE_SHIFT;
1797 
1798 		cur_sgl = sgl;
1799 		for (i = 0; i < hvpg_count; i++) {
1800 			/*
1801 			 * 'i' is the index of hv pages in the payload and
1802 			 * 'hvpgoff' is the offset (in hv pages) of the first
1803 			 * hv page in the the first page. The relationship
1804 			 * between the sum of 'i' and 'hvpgoff' and the offset
1805 			 * (in hv pages) in a payload page ('hvpgoff_in_page')
1806 			 * is as follow:
1807 			 *
1808 			 * |------------------ PAGE -------------------|
1809 			 * |   NR_HV_HYP_PAGES_IN_PAGE hvpgs in total  |
1810 			 * |hvpg|hvpg| ...              |hvpg|... |hvpg|
1811 			 * ^         ^                                 ^                 ^
1812 			 * +-hvpgoff-+                                 +-hvpgoff_in_page-+
1813 			 *           ^                                                   |
1814 			 *           +--------------------- i ---------------------------+
1815 			 */
1816 			unsigned int hvpgoff_in_page =
1817 				(i + hvpgoff) % NR_HV_HYP_PAGES_IN_PAGE;
1818 
1819 			/*
1820 			 * Two cases that we need to fetch a page:
1821 			 * 1) i == 0, the first step or
1822 			 * 2) hvpgoff_in_page == 0, when we reach the boundary
1823 			 *    of a page.
1824 			 */
1825 			if (hvpgoff_in_page == 0 || i == 0) {
1826 				hvpfn = page_to_hvpfn(sg_page(cur_sgl));
1827 				cur_sgl = sg_next(cur_sgl);
1828 			}
1829 
1830 			payload->range.pfn_array[i] = hvpfn + hvpgoff_in_page;
1831 		}
1832 	}
1833 
1834 	cmd_request->payload = payload;
1835 	cmd_request->payload_sz = payload_sz;
1836 
1837 	/* Invokes the vsc to start an IO */
1838 	ret = storvsc_do_io(dev, cmd_request, get_cpu());
1839 	put_cpu();
1840 
1841 	if (ret == -EAGAIN) {
1842 		if (payload_sz > sizeof(cmd_request->mpb))
1843 			kfree(payload);
1844 		/* no more space */
1845 		return SCSI_MLQUEUE_DEVICE_BUSY;
1846 	}
1847 
1848 	return 0;
1849 }
1850 
1851 static struct scsi_host_template scsi_driver = {
1852 	.module	=		THIS_MODULE,
1853 	.name =			"storvsc_host_t",
1854 	.cmd_size =             sizeof(struct storvsc_cmd_request),
1855 	.bios_param =		storvsc_get_chs,
1856 	.queuecommand =		storvsc_queuecommand,
1857 	.eh_host_reset_handler =	storvsc_host_reset_handler,
1858 	.proc_name =		"storvsc_host",
1859 	.eh_timed_out =		storvsc_eh_timed_out,
1860 	.slave_alloc =		storvsc_device_alloc,
1861 	.slave_configure =	storvsc_device_configure,
1862 	.cmd_per_lun =		2048,
1863 	.this_id =		-1,
1864 	/* Make sure we dont get a sg segment crosses a page boundary */
1865 	.dma_boundary =		PAGE_SIZE-1,
1866 	/* Ensure there are no gaps in presented sgls */
1867 	.virt_boundary_mask =	PAGE_SIZE-1,
1868 	.no_write_same =	1,
1869 	.track_queue_depth =	1,
1870 	.change_queue_depth =	storvsc_change_queue_depth,
1871 };
1872 
1873 enum {
1874 	SCSI_GUID,
1875 	IDE_GUID,
1876 	SFC_GUID,
1877 };
1878 
1879 static const struct hv_vmbus_device_id id_table[] = {
1880 	/* SCSI guid */
1881 	{ HV_SCSI_GUID,
1882 	  .driver_data = SCSI_GUID
1883 	},
1884 	/* IDE guid */
1885 	{ HV_IDE_GUID,
1886 	  .driver_data = IDE_GUID
1887 	},
1888 	/* Fibre Channel GUID */
1889 	{
1890 	  HV_SYNTHFC_GUID,
1891 	  .driver_data = SFC_GUID
1892 	},
1893 	{ },
1894 };
1895 
1896 MODULE_DEVICE_TABLE(vmbus, id_table);
1897 
1898 static const struct { guid_t guid; } fc_guid = { HV_SYNTHFC_GUID };
1899 
1900 static bool hv_dev_is_fc(struct hv_device *hv_dev)
1901 {
1902 	return guid_equal(&fc_guid.guid, &hv_dev->dev_type);
1903 }
1904 
1905 static int storvsc_probe(struct hv_device *device,
1906 			const struct hv_vmbus_device_id *dev_id)
1907 {
1908 	int ret;
1909 	int num_cpus = num_online_cpus();
1910 	struct Scsi_Host *host;
1911 	struct hv_host_device *host_dev;
1912 	bool dev_is_ide = ((dev_id->driver_data == IDE_GUID) ? true : false);
1913 	bool is_fc = ((dev_id->driver_data == SFC_GUID) ? true : false);
1914 	int target = 0;
1915 	struct storvsc_device *stor_device;
1916 	int max_luns_per_target;
1917 	int max_targets;
1918 	int max_channels;
1919 	int max_sub_channels = 0;
1920 
1921 	/*
1922 	 * Based on the windows host we are running on,
1923 	 * set state to properly communicate with the host.
1924 	 */
1925 
1926 	if (vmbus_proto_version < VERSION_WIN8) {
1927 		max_luns_per_target = STORVSC_IDE_MAX_LUNS_PER_TARGET;
1928 		max_targets = STORVSC_IDE_MAX_TARGETS;
1929 		max_channels = STORVSC_IDE_MAX_CHANNELS;
1930 	} else {
1931 		max_luns_per_target = STORVSC_MAX_LUNS_PER_TARGET;
1932 		max_targets = STORVSC_MAX_TARGETS;
1933 		max_channels = STORVSC_MAX_CHANNELS;
1934 		/*
1935 		 * On Windows8 and above, we support sub-channels for storage
1936 		 * 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 
1945 	scsi_driver.can_queue = max_outstanding_req_per_channel *
1946 				(max_sub_channels + 1) *
1947 				(100 - ring_avail_percent_lowater) / 100;
1948 
1949 	host = scsi_host_alloc(&scsi_driver,
1950 			       sizeof(struct hv_host_device));
1951 	if (!host)
1952 		return -ENOMEM;
1953 
1954 	host_dev = shost_priv(host);
1955 	memset(host_dev, 0, sizeof(struct hv_host_device));
1956 
1957 	host_dev->port = host->host_no;
1958 	host_dev->dev = device;
1959 	host_dev->host = host;
1960 
1961 
1962 	stor_device = kzalloc(sizeof(struct storvsc_device), GFP_KERNEL);
1963 	if (!stor_device) {
1964 		ret = -ENOMEM;
1965 		goto err_out0;
1966 	}
1967 
1968 	stor_device->destroy = false;
1969 	init_waitqueue_head(&stor_device->waiting_to_drain);
1970 	stor_device->device = device;
1971 	stor_device->host = host;
1972 	stor_device->vmscsi_size_delta = sizeof(struct vmscsi_win8_extension);
1973 	spin_lock_init(&stor_device->lock);
1974 	hv_set_drvdata(device, stor_device);
1975 
1976 	stor_device->port_number = host->host_no;
1977 	ret = storvsc_connect_to_vsp(device, storvsc_ringbuffer_size, is_fc);
1978 	if (ret)
1979 		goto err_out1;
1980 
1981 	host_dev->path = stor_device->path_id;
1982 	host_dev->target = stor_device->target_id;
1983 
1984 	switch (dev_id->driver_data) {
1985 	case SFC_GUID:
1986 		host->max_lun = STORVSC_FC_MAX_LUNS_PER_TARGET;
1987 		host->max_id = STORVSC_FC_MAX_TARGETS;
1988 		host->max_channel = STORVSC_FC_MAX_CHANNELS - 1;
1989 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
1990 		host->transportt = fc_transport_template;
1991 #endif
1992 		break;
1993 
1994 	case SCSI_GUID:
1995 		host->max_lun = max_luns_per_target;
1996 		host->max_id = max_targets;
1997 		host->max_channel = max_channels - 1;
1998 		break;
1999 
2000 	default:
2001 		host->max_lun = STORVSC_IDE_MAX_LUNS_PER_TARGET;
2002 		host->max_id = STORVSC_IDE_MAX_TARGETS;
2003 		host->max_channel = STORVSC_IDE_MAX_CHANNELS - 1;
2004 		break;
2005 	}
2006 	/* max cmd length */
2007 	host->max_cmd_len = STORVSC_MAX_CMD_LEN;
2008 
2009 	/*
2010 	 * set the table size based on the info we got
2011 	 * from the host.
2012 	 */
2013 	host->sg_tablesize = (stor_device->max_transfer_bytes >> PAGE_SHIFT);
2014 	/*
2015 	 * For non-IDE disks, the host supports multiple channels.
2016 	 * Set the number of HW queues we are supporting.
2017 	 */
2018 	if (!dev_is_ide)
2019 		host->nr_hw_queues = num_present_cpus();
2020 
2021 	/*
2022 	 * Set the error handler work queue.
2023 	 */
2024 	host_dev->handle_error_wq =
2025 			alloc_ordered_workqueue("storvsc_error_wq_%d",
2026 						WQ_MEM_RECLAIM,
2027 						host->host_no);
2028 	if (!host_dev->handle_error_wq) {
2029 		ret = -ENOMEM;
2030 		goto err_out2;
2031 	}
2032 	INIT_WORK(&host_dev->host_scan_work, storvsc_host_scan);
2033 	/* Register the HBA and start the scsi bus scan */
2034 	ret = scsi_add_host(host, &device->device);
2035 	if (ret != 0)
2036 		goto err_out3;
2037 
2038 	if (!dev_is_ide) {
2039 		scsi_scan_host(host);
2040 	} else {
2041 		target = (device->dev_instance.b[5] << 8 |
2042 			 device->dev_instance.b[4]);
2043 		ret = scsi_add_device(host, 0, target, 0);
2044 		if (ret)
2045 			goto err_out4;
2046 	}
2047 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
2048 	if (host->transportt == fc_transport_template) {
2049 		struct fc_rport_identifiers ids = {
2050 			.roles = FC_PORT_ROLE_FCP_DUMMY_INITIATOR,
2051 		};
2052 
2053 		fc_host_node_name(host) = stor_device->node_name;
2054 		fc_host_port_name(host) = stor_device->port_name;
2055 		stor_device->rport = fc_remote_port_add(host, 0, &ids);
2056 		if (!stor_device->rport) {
2057 			ret = -ENOMEM;
2058 			goto err_out4;
2059 		}
2060 	}
2061 #endif
2062 	return 0;
2063 
2064 err_out4:
2065 	scsi_remove_host(host);
2066 
2067 err_out3:
2068 	destroy_workqueue(host_dev->handle_error_wq);
2069 
2070 err_out2:
2071 	/*
2072 	 * Once we have connected with the host, we would need to
2073 	 * to invoke storvsc_dev_remove() to rollback this state and
2074 	 * this call also frees up the stor_device; hence the jump around
2075 	 * err_out1 label.
2076 	 */
2077 	storvsc_dev_remove(device);
2078 	goto err_out0;
2079 
2080 err_out1:
2081 	kfree(stor_device->stor_chns);
2082 	kfree(stor_device);
2083 
2084 err_out0:
2085 	scsi_host_put(host);
2086 	return ret;
2087 }
2088 
2089 /* Change a scsi target's queue depth */
2090 static int storvsc_change_queue_depth(struct scsi_device *sdev, int queue_depth)
2091 {
2092 	if (queue_depth > scsi_driver.can_queue)
2093 		queue_depth = scsi_driver.can_queue;
2094 
2095 	return scsi_change_queue_depth(sdev, queue_depth);
2096 }
2097 
2098 static int storvsc_remove(struct hv_device *dev)
2099 {
2100 	struct storvsc_device *stor_device = hv_get_drvdata(dev);
2101 	struct Scsi_Host *host = stor_device->host;
2102 	struct hv_host_device *host_dev = shost_priv(host);
2103 
2104 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
2105 	if (host->transportt == fc_transport_template) {
2106 		fc_remote_port_delete(stor_device->rport);
2107 		fc_remove_host(host);
2108 	}
2109 #endif
2110 	destroy_workqueue(host_dev->handle_error_wq);
2111 	scsi_remove_host(host);
2112 	storvsc_dev_remove(dev);
2113 	scsi_host_put(host);
2114 
2115 	return 0;
2116 }
2117 
2118 static int storvsc_suspend(struct hv_device *hv_dev)
2119 {
2120 	struct storvsc_device *stor_device = hv_get_drvdata(hv_dev);
2121 	struct Scsi_Host *host = stor_device->host;
2122 	struct hv_host_device *host_dev = shost_priv(host);
2123 
2124 	storvsc_wait_to_drain(stor_device);
2125 
2126 	drain_workqueue(host_dev->handle_error_wq);
2127 
2128 	vmbus_close(hv_dev->channel);
2129 
2130 	kfree(stor_device->stor_chns);
2131 	stor_device->stor_chns = NULL;
2132 
2133 	cpumask_clear(&stor_device->alloced_cpus);
2134 
2135 	return 0;
2136 }
2137 
2138 static int storvsc_resume(struct hv_device *hv_dev)
2139 {
2140 	int ret;
2141 
2142 	ret = storvsc_connect_to_vsp(hv_dev, storvsc_ringbuffer_size,
2143 				     hv_dev_is_fc(hv_dev));
2144 	return ret;
2145 }
2146 
2147 static struct hv_driver storvsc_drv = {
2148 	.name = KBUILD_MODNAME,
2149 	.id_table = id_table,
2150 	.probe = storvsc_probe,
2151 	.remove = storvsc_remove,
2152 	.suspend = storvsc_suspend,
2153 	.resume = storvsc_resume,
2154 	.driver = {
2155 		.probe_type = PROBE_PREFER_ASYNCHRONOUS,
2156 	},
2157 };
2158 
2159 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
2160 static struct fc_function_template fc_transport_functions = {
2161 	.show_host_node_name = 1,
2162 	.show_host_port_name = 1,
2163 };
2164 #endif
2165 
2166 static int __init storvsc_drv_init(void)
2167 {
2168 	int ret;
2169 
2170 	/*
2171 	 * Divide the ring buffer data size (which is 1 page less
2172 	 * than the ring buffer size since that page is reserved for
2173 	 * the ring buffer indices) by the max request size (which is
2174 	 * vmbus_channel_packet_multipage_buffer + struct vstor_packet + u64)
2175 	 *
2176 	 * The computation underestimates max_outstanding_req_per_channel
2177 	 * for Win7 and older hosts because it does not take into account
2178 	 * the vmscsi_size_delta correction to the max request size.
2179 	 */
2180 	max_outstanding_req_per_channel =
2181 		((storvsc_ringbuffer_size - PAGE_SIZE) /
2182 		ALIGN(MAX_MULTIPAGE_BUFFER_PACKET +
2183 		sizeof(struct vstor_packet) + sizeof(u64),
2184 		sizeof(u64)));
2185 
2186 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
2187 	fc_transport_template = fc_attach_transport(&fc_transport_functions);
2188 	if (!fc_transport_template)
2189 		return -ENODEV;
2190 #endif
2191 
2192 	ret = vmbus_driver_register(&storvsc_drv);
2193 
2194 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
2195 	if (ret)
2196 		fc_release_transport(fc_transport_template);
2197 #endif
2198 
2199 	return ret;
2200 }
2201 
2202 static void __exit storvsc_drv_exit(void)
2203 {
2204 	vmbus_driver_unregister(&storvsc_drv);
2205 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
2206 	fc_release_transport(fc_transport_template);
2207 #endif
2208 }
2209 
2210 MODULE_LICENSE("GPL");
2211 MODULE_DESCRIPTION("Microsoft Hyper-V virtual storage driver");
2212 module_init(storvsc_drv_init);
2213 module_exit(storvsc_drv_exit);
2214