xref: /openbmc/linux/drivers/scsi/storvsc_drv.c (revision 2169e6da)
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 /*
221  * The size of the vmscsi_request has changed in win8. The
222  * additional size is because of new elements added to the
223  * structure. These elements are valid only when we are talking
224  * to a win8 host.
225  * Track the correction to size we need to apply. This value
226  * will likely change during protocol negotiation but it is
227  * valid to start by assuming pre-Win8.
228  */
229 static int vmscsi_size_delta = sizeof(struct vmscsi_win8_extension);
230 
231 /*
232  * The list of storage protocols in order of preference.
233  */
234 struct vmstor_protocol {
235 	int protocol_version;
236 	int sense_buffer_size;
237 	int vmscsi_size_delta;
238 };
239 
240 
241 static const struct vmstor_protocol vmstor_protocols[] = {
242 	{
243 		VMSTOR_PROTO_VERSION_WIN10,
244 		POST_WIN7_STORVSC_SENSE_BUFFER_SIZE,
245 		0
246 	},
247 	{
248 		VMSTOR_PROTO_VERSION_WIN8_1,
249 		POST_WIN7_STORVSC_SENSE_BUFFER_SIZE,
250 		0
251 	},
252 	{
253 		VMSTOR_PROTO_VERSION_WIN8,
254 		POST_WIN7_STORVSC_SENSE_BUFFER_SIZE,
255 		0
256 	},
257 	{
258 		VMSTOR_PROTO_VERSION_WIN7,
259 		PRE_WIN8_STORVSC_SENSE_BUFFER_SIZE,
260 		sizeof(struct vmscsi_win8_extension),
261 	},
262 	{
263 		VMSTOR_PROTO_VERSION_WIN6,
264 		PRE_WIN8_STORVSC_SENSE_BUFFER_SIZE,
265 		sizeof(struct vmscsi_win8_extension),
266 	}
267 };
268 
269 
270 /*
271  * This structure is sent during the initialization phase to get the different
272  * properties of the channel.
273  */
274 
275 #define STORAGE_CHANNEL_SUPPORTS_MULTI_CHANNEL		0x1
276 
277 struct vmstorage_channel_properties {
278 	u32 reserved;
279 	u16 max_channel_cnt;
280 	u16 reserved1;
281 
282 	u32 flags;
283 	u32   max_transfer_bytes;
284 
285 	u64  reserved2;
286 } __packed;
287 
288 /*  This structure is sent during the storage protocol negotiations. */
289 struct vmstorage_protocol_version {
290 	/* Major (MSW) and minor (LSW) version numbers. */
291 	u16 major_minor;
292 
293 	/*
294 	 * Revision number is auto-incremented whenever this file is changed
295 	 * (See FILL_VMSTOR_REVISION macro above).  Mismatch does not
296 	 * definitely indicate incompatibility--but it does indicate mismatched
297 	 * builds.
298 	 * This is only used on the windows side. Just set it to 0.
299 	 */
300 	u16 revision;
301 } __packed;
302 
303 /* Channel Property Flags */
304 #define STORAGE_CHANNEL_REMOVABLE_FLAG		0x1
305 #define STORAGE_CHANNEL_EMULATED_IDE_FLAG	0x2
306 
307 struct vstor_packet {
308 	/* Requested operation type */
309 	enum vstor_packet_operation operation;
310 
311 	/*  Flags - see below for values */
312 	u32 flags;
313 
314 	/* Status of the request returned from the server side. */
315 	u32 status;
316 
317 	/* Data payload area */
318 	union {
319 		/*
320 		 * Structure used to forward SCSI commands from the
321 		 * client to the server.
322 		 */
323 		struct vmscsi_request vm_srb;
324 
325 		/* Structure used to query channel properties. */
326 		struct vmstorage_channel_properties storage_channel_properties;
327 
328 		/* Used during version negotiations. */
329 		struct vmstorage_protocol_version version;
330 
331 		/* Fibre channel address packet */
332 		struct hv_fc_wwn_packet wwn_packet;
333 
334 		/* Number of sub-channels to create */
335 		u16 sub_channel_count;
336 
337 		/* This will be the maximum of the union members */
338 		u8  buffer[0x34];
339 	};
340 } __packed;
341 
342 /*
343  * Packet Flags:
344  *
345  * This flag indicates that the server should send back a completion for this
346  * packet.
347  */
348 
349 #define REQUEST_COMPLETION_FLAG	0x1
350 
351 /* Matches Windows-end */
352 enum storvsc_request_type {
353 	WRITE_TYPE = 0,
354 	READ_TYPE,
355 	UNKNOWN_TYPE,
356 };
357 
358 /*
359  * SRB status codes and masks; a subset of the codes used here.
360  */
361 
362 #define SRB_STATUS_AUTOSENSE_VALID	0x80
363 #define SRB_STATUS_QUEUE_FROZEN		0x40
364 #define SRB_STATUS_INVALID_LUN	0x20
365 #define SRB_STATUS_SUCCESS	0x01
366 #define SRB_STATUS_ABORTED	0x02
367 #define SRB_STATUS_ERROR	0x04
368 #define SRB_STATUS_DATA_OVERRUN	0x12
369 
370 #define SRB_STATUS(status) \
371 	(status & ~(SRB_STATUS_AUTOSENSE_VALID | SRB_STATUS_QUEUE_FROZEN))
372 /*
373  * This is the end of Protocol specific defines.
374  */
375 
376 static int storvsc_ringbuffer_size = (128 * 1024);
377 static u32 max_outstanding_req_per_channel;
378 static int storvsc_change_queue_depth(struct scsi_device *sdev, int queue_depth);
379 
380 static int storvsc_vcpus_per_sub_channel = 4;
381 
382 module_param(storvsc_ringbuffer_size, int, S_IRUGO);
383 MODULE_PARM_DESC(storvsc_ringbuffer_size, "Ring buffer size (bytes)");
384 
385 module_param(storvsc_vcpus_per_sub_channel, int, S_IRUGO);
386 MODULE_PARM_DESC(storvsc_vcpus_per_sub_channel, "Ratio of VCPUs to subchannels");
387 
388 static int ring_avail_percent_lowater = 10;
389 module_param(ring_avail_percent_lowater, int, S_IRUGO);
390 MODULE_PARM_DESC(ring_avail_percent_lowater,
391 		"Select a channel if available ring size > this in percent");
392 
393 /*
394  * Timeout in seconds for all devices managed by this driver.
395  */
396 static int storvsc_timeout = 180;
397 
398 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
399 static struct scsi_transport_template *fc_transport_template;
400 #endif
401 
402 static void storvsc_on_channel_callback(void *context);
403 
404 #define STORVSC_MAX_LUNS_PER_TARGET			255
405 #define STORVSC_MAX_TARGETS				2
406 #define STORVSC_MAX_CHANNELS				8
407 
408 #define STORVSC_FC_MAX_LUNS_PER_TARGET			255
409 #define STORVSC_FC_MAX_TARGETS				128
410 #define STORVSC_FC_MAX_CHANNELS				8
411 
412 #define STORVSC_IDE_MAX_LUNS_PER_TARGET			64
413 #define STORVSC_IDE_MAX_TARGETS				1
414 #define STORVSC_IDE_MAX_CHANNELS			1
415 
416 struct storvsc_cmd_request {
417 	struct scsi_cmnd *cmd;
418 
419 	struct hv_device *device;
420 
421 	/* Synchronize the request/response if needed */
422 	struct completion wait_event;
423 
424 	struct vmbus_channel_packet_multipage_buffer mpb;
425 	struct vmbus_packet_mpb_array *payload;
426 	u32 payload_sz;
427 
428 	struct vstor_packet vstor_packet;
429 };
430 
431 
432 /* A storvsc device is a device object that contains a vmbus channel */
433 struct storvsc_device {
434 	struct hv_device *device;
435 
436 	bool	 destroy;
437 	bool	 drain_notify;
438 	atomic_t num_outstanding_req;
439 	struct Scsi_Host *host;
440 
441 	wait_queue_head_t waiting_to_drain;
442 
443 	/*
444 	 * Each unique Port/Path/Target represents 1 channel ie scsi
445 	 * controller. In reality, the pathid, targetid is always 0
446 	 * and the port is set by us
447 	 */
448 	unsigned int port_number;
449 	unsigned char path_id;
450 	unsigned char target_id;
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 	/* Used for vsc/vsp channel reset process */
466 	struct storvsc_cmd_request init_request;
467 	struct storvsc_cmd_request reset_request;
468 	/*
469 	 * Currently active port and node names for FC devices.
470 	 */
471 	u64 node_name;
472 	u64 port_name;
473 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
474 	struct fc_rport *rport;
475 #endif
476 };
477 
478 struct hv_host_device {
479 	struct hv_device *dev;
480 	unsigned int port;
481 	unsigned char path;
482 	unsigned char target;
483 	struct workqueue_struct *handle_error_wq;
484 	struct work_struct host_scan_work;
485 	struct Scsi_Host *host;
486 };
487 
488 struct storvsc_scan_work {
489 	struct work_struct work;
490 	struct Scsi_Host *host;
491 	u8 lun;
492 	u8 tgt_id;
493 };
494 
495 static void storvsc_device_scan(struct work_struct *work)
496 {
497 	struct storvsc_scan_work *wrk;
498 	struct scsi_device *sdev;
499 
500 	wrk = container_of(work, struct storvsc_scan_work, work);
501 
502 	sdev = scsi_device_lookup(wrk->host, 0, wrk->tgt_id, wrk->lun);
503 	if (!sdev)
504 		goto done;
505 	scsi_rescan_device(&sdev->sdev_gendev);
506 	scsi_device_put(sdev);
507 
508 done:
509 	kfree(wrk);
510 }
511 
512 static void storvsc_host_scan(struct work_struct *work)
513 {
514 	struct Scsi_Host *host;
515 	struct scsi_device *sdev;
516 	struct hv_host_device *host_device =
517 		container_of(work, struct hv_host_device, host_scan_work);
518 
519 	host = host_device->host;
520 	/*
521 	 * Before scanning the host, first check to see if any of the
522 	 * currrently known devices have been hot removed. We issue a
523 	 * "unit ready" command against all currently known devices.
524 	 * This I/O will result in an error for devices that have been
525 	 * removed. As part of handling the I/O error, we remove the device.
526 	 *
527 	 * When a LUN is added or removed, the host sends us a signal to
528 	 * scan the host. Thus we are forced to discover the LUNs that
529 	 * may have been removed this way.
530 	 */
531 	mutex_lock(&host->scan_mutex);
532 	shost_for_each_device(sdev, host)
533 		scsi_test_unit_ready(sdev, 1, 1, NULL);
534 	mutex_unlock(&host->scan_mutex);
535 	/*
536 	 * Now scan the host to discover LUNs that may have been added.
537 	 */
538 	scsi_scan_host(host);
539 }
540 
541 static void storvsc_remove_lun(struct work_struct *work)
542 {
543 	struct storvsc_scan_work *wrk;
544 	struct scsi_device *sdev;
545 
546 	wrk = container_of(work, struct storvsc_scan_work, work);
547 	if (!scsi_host_get(wrk->host))
548 		goto done;
549 
550 	sdev = scsi_device_lookup(wrk->host, 0, wrk->tgt_id, wrk->lun);
551 
552 	if (sdev) {
553 		scsi_remove_device(sdev);
554 		scsi_device_put(sdev);
555 	}
556 	scsi_host_put(wrk->host);
557 
558 done:
559 	kfree(wrk);
560 }
561 
562 
563 /*
564  * We can get incoming messages from the host that are not in response to
565  * messages that we have sent out. An example of this would be messages
566  * received by the guest to notify dynamic addition/removal of LUNs. To
567  * deal with potential race conditions where the driver may be in the
568  * midst of being unloaded when we might receive an unsolicited message
569  * from the host, we have implemented a mechanism to gurantee sequential
570  * consistency:
571  *
572  * 1) Once the device is marked as being destroyed, we will fail all
573  *    outgoing messages.
574  * 2) We permit incoming messages when the device is being destroyed,
575  *    only to properly account for messages already sent out.
576  */
577 
578 static inline struct storvsc_device *get_out_stor_device(
579 					struct hv_device *device)
580 {
581 	struct storvsc_device *stor_device;
582 
583 	stor_device = hv_get_drvdata(device);
584 
585 	if (stor_device && stor_device->destroy)
586 		stor_device = NULL;
587 
588 	return stor_device;
589 }
590 
591 
592 static inline void storvsc_wait_to_drain(struct storvsc_device *dev)
593 {
594 	dev->drain_notify = true;
595 	wait_event(dev->waiting_to_drain,
596 		   atomic_read(&dev->num_outstanding_req) == 0);
597 	dev->drain_notify = false;
598 }
599 
600 static inline struct storvsc_device *get_in_stor_device(
601 					struct hv_device *device)
602 {
603 	struct storvsc_device *stor_device;
604 
605 	stor_device = hv_get_drvdata(device);
606 
607 	if (!stor_device)
608 		goto get_in_err;
609 
610 	/*
611 	 * If the device is being destroyed; allow incoming
612 	 * traffic only to cleanup outstanding requests.
613 	 */
614 
615 	if (stor_device->destroy  &&
616 		(atomic_read(&stor_device->num_outstanding_req) == 0))
617 		stor_device = NULL;
618 
619 get_in_err:
620 	return stor_device;
621 
622 }
623 
624 static void handle_sc_creation(struct vmbus_channel *new_sc)
625 {
626 	struct hv_device *device = new_sc->primary_channel->device_obj;
627 	struct device *dev = &device->device;
628 	struct storvsc_device *stor_device;
629 	struct vmstorage_channel_properties props;
630 	int ret;
631 
632 	stor_device = get_out_stor_device(device);
633 	if (!stor_device)
634 		return;
635 
636 	memset(&props, 0, sizeof(struct vmstorage_channel_properties));
637 
638 	ret = vmbus_open(new_sc,
639 			 storvsc_ringbuffer_size,
640 			 storvsc_ringbuffer_size,
641 			 (void *)&props,
642 			 sizeof(struct vmstorage_channel_properties),
643 			 storvsc_on_channel_callback, new_sc);
644 
645 	/* In case vmbus_open() fails, we don't use the sub-channel. */
646 	if (ret != 0) {
647 		dev_err(dev, "Failed to open sub-channel: err=%d\n", ret);
648 		return;
649 	}
650 
651 	/* Add the sub-channel to the array of available channels. */
652 	stor_device->stor_chns[new_sc->target_cpu] = new_sc;
653 	cpumask_set_cpu(new_sc->target_cpu, &stor_device->alloced_cpus);
654 }
655 
656 static void  handle_multichannel_storage(struct hv_device *device, int max_chns)
657 {
658 	struct device *dev = &device->device;
659 	struct storvsc_device *stor_device;
660 	int num_sc;
661 	struct storvsc_cmd_request *request;
662 	struct vstor_packet *vstor_packet;
663 	int ret, t;
664 
665 	/*
666 	 * If the number of CPUs is artificially restricted, such as
667 	 * with maxcpus=1 on the kernel boot line, Hyper-V could offer
668 	 * sub-channels >= the number of CPUs. These sub-channels
669 	 * should not be created. The primary channel is already created
670 	 * and assigned to one CPU, so check against # CPUs - 1.
671 	 */
672 	num_sc = min((int)(num_online_cpus() - 1), max_chns);
673 	if (!num_sc)
674 		return;
675 
676 	stor_device = get_out_stor_device(device);
677 	if (!stor_device)
678 		return;
679 
680 	stor_device->num_sc = num_sc;
681 	request = &stor_device->init_request;
682 	vstor_packet = &request->vstor_packet;
683 
684 	/*
685 	 * Establish a handler for dealing with subchannels.
686 	 */
687 	vmbus_set_sc_create_callback(device->channel, handle_sc_creation);
688 
689 	/*
690 	 * Request the host to create sub-channels.
691 	 */
692 	memset(request, 0, sizeof(struct storvsc_cmd_request));
693 	init_completion(&request->wait_event);
694 	vstor_packet->operation = VSTOR_OPERATION_CREATE_SUB_CHANNELS;
695 	vstor_packet->flags = REQUEST_COMPLETION_FLAG;
696 	vstor_packet->sub_channel_count = num_sc;
697 
698 	ret = vmbus_sendpacket(device->channel, vstor_packet,
699 			       (sizeof(struct vstor_packet) -
700 			       vmscsi_size_delta),
701 			       (unsigned long)request,
702 			       VM_PKT_DATA_INBAND,
703 			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
704 
705 	if (ret != 0) {
706 		dev_err(dev, "Failed to create sub-channel: err=%d\n", ret);
707 		return;
708 	}
709 
710 	t = wait_for_completion_timeout(&request->wait_event, 10*HZ);
711 	if (t == 0) {
712 		dev_err(dev, "Failed to create sub-channel: timed out\n");
713 		return;
714 	}
715 
716 	if (vstor_packet->operation != VSTOR_OPERATION_COMPLETE_IO ||
717 	    vstor_packet->status != 0) {
718 		dev_err(dev, "Failed to create sub-channel: op=%d, sts=%d\n",
719 			vstor_packet->operation, vstor_packet->status);
720 		return;
721 	}
722 
723 	/*
724 	 * We need to do nothing here, because vmbus_process_offer()
725 	 * invokes channel->sc_creation_callback, which will open and use
726 	 * the sub-channel(s).
727 	 */
728 }
729 
730 static void cache_wwn(struct storvsc_device *stor_device,
731 		      struct vstor_packet *vstor_packet)
732 {
733 	/*
734 	 * Cache the currently active port and node ww names.
735 	 */
736 	if (vstor_packet->wwn_packet.primary_active) {
737 		stor_device->node_name =
738 			wwn_to_u64(vstor_packet->wwn_packet.primary_node_wwn);
739 		stor_device->port_name =
740 			wwn_to_u64(vstor_packet->wwn_packet.primary_port_wwn);
741 	} else {
742 		stor_device->node_name =
743 			wwn_to_u64(vstor_packet->wwn_packet.secondary_node_wwn);
744 		stor_device->port_name =
745 			wwn_to_u64(vstor_packet->wwn_packet.secondary_port_wwn);
746 	}
747 }
748 
749 
750 static int storvsc_execute_vstor_op(struct hv_device *device,
751 				    struct storvsc_cmd_request *request,
752 				    bool status_check)
753 {
754 	struct vstor_packet *vstor_packet;
755 	int ret, t;
756 
757 	vstor_packet = &request->vstor_packet;
758 
759 	init_completion(&request->wait_event);
760 	vstor_packet->flags = REQUEST_COMPLETION_FLAG;
761 
762 	ret = vmbus_sendpacket(device->channel, vstor_packet,
763 			       (sizeof(struct vstor_packet) -
764 			       vmscsi_size_delta),
765 			       (unsigned long)request,
766 			       VM_PKT_DATA_INBAND,
767 			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
768 	if (ret != 0)
769 		return ret;
770 
771 	t = wait_for_completion_timeout(&request->wait_event, 5*HZ);
772 	if (t == 0)
773 		return -ETIMEDOUT;
774 
775 	if (!status_check)
776 		return ret;
777 
778 	if (vstor_packet->operation != VSTOR_OPERATION_COMPLETE_IO ||
779 	    vstor_packet->status != 0)
780 		return -EINVAL;
781 
782 	return ret;
783 }
784 
785 static int storvsc_channel_init(struct hv_device *device, bool is_fc)
786 {
787 	struct storvsc_device *stor_device;
788 	struct storvsc_cmd_request *request;
789 	struct vstor_packet *vstor_packet;
790 	int ret, i;
791 	int max_chns;
792 	bool process_sub_channels = false;
793 
794 	stor_device = get_out_stor_device(device);
795 	if (!stor_device)
796 		return -ENODEV;
797 
798 	request = &stor_device->init_request;
799 	vstor_packet = &request->vstor_packet;
800 
801 	/*
802 	 * Now, initiate the vsc/vsp initialization protocol on the open
803 	 * channel
804 	 */
805 	memset(request, 0, sizeof(struct storvsc_cmd_request));
806 	vstor_packet->operation = VSTOR_OPERATION_BEGIN_INITIALIZATION;
807 	ret = storvsc_execute_vstor_op(device, request, true);
808 	if (ret)
809 		return ret;
810 	/*
811 	 * Query host supported protocol version.
812 	 */
813 
814 	for (i = 0; i < ARRAY_SIZE(vmstor_protocols); i++) {
815 		/* reuse the packet for version range supported */
816 		memset(vstor_packet, 0, sizeof(struct vstor_packet));
817 		vstor_packet->operation =
818 			VSTOR_OPERATION_QUERY_PROTOCOL_VERSION;
819 
820 		vstor_packet->version.major_minor =
821 			vmstor_protocols[i].protocol_version;
822 
823 		/*
824 		 * The revision number is only used in Windows; set it to 0.
825 		 */
826 		vstor_packet->version.revision = 0;
827 		ret = storvsc_execute_vstor_op(device, request, false);
828 		if (ret != 0)
829 			return ret;
830 
831 		if (vstor_packet->operation != VSTOR_OPERATION_COMPLETE_IO)
832 			return -EINVAL;
833 
834 		if (vstor_packet->status == 0) {
835 			vmstor_proto_version =
836 				vmstor_protocols[i].protocol_version;
837 
838 			sense_buffer_size =
839 				vmstor_protocols[i].sense_buffer_size;
840 
841 			vmscsi_size_delta =
842 				vmstor_protocols[i].vmscsi_size_delta;
843 
844 			break;
845 		}
846 	}
847 
848 	if (vstor_packet->status != 0)
849 		return -EINVAL;
850 
851 
852 	memset(vstor_packet, 0, sizeof(struct vstor_packet));
853 	vstor_packet->operation = VSTOR_OPERATION_QUERY_PROPERTIES;
854 	ret = storvsc_execute_vstor_op(device, request, true);
855 	if (ret != 0)
856 		return ret;
857 
858 	/*
859 	 * Check to see if multi-channel support is there.
860 	 * Hosts that implement protocol version of 5.1 and above
861 	 * support multi-channel.
862 	 */
863 	max_chns = vstor_packet->storage_channel_properties.max_channel_cnt;
864 
865 	/*
866 	 * Allocate state to manage the sub-channels.
867 	 * We allocate an array based on the numbers of possible CPUs
868 	 * (Hyper-V does not support cpu online/offline).
869 	 * This Array will be sparseley populated with unique
870 	 * channels - primary + sub-channels.
871 	 * We will however populate all the slots to evenly distribute
872 	 * the load.
873 	 */
874 	stor_device->stor_chns = kcalloc(num_possible_cpus(), sizeof(void *),
875 					 GFP_KERNEL);
876 	if (stor_device->stor_chns == NULL)
877 		return -ENOMEM;
878 
879 	stor_device->stor_chns[device->channel->target_cpu] = device->channel;
880 	cpumask_set_cpu(device->channel->target_cpu,
881 			&stor_device->alloced_cpus);
882 
883 	if (vmstor_proto_version >= VMSTOR_PROTO_VERSION_WIN8) {
884 		if (vstor_packet->storage_channel_properties.flags &
885 		    STORAGE_CHANNEL_SUPPORTS_MULTI_CHANNEL)
886 			process_sub_channels = true;
887 	}
888 	stor_device->max_transfer_bytes =
889 		vstor_packet->storage_channel_properties.max_transfer_bytes;
890 
891 	if (!is_fc)
892 		goto done;
893 
894 	/*
895 	 * For FC devices retrieve FC HBA data.
896 	 */
897 	memset(vstor_packet, 0, sizeof(struct vstor_packet));
898 	vstor_packet->operation = VSTOR_OPERATION_FCHBA_DATA;
899 	ret = storvsc_execute_vstor_op(device, request, true);
900 	if (ret != 0)
901 		return ret;
902 
903 	/*
904 	 * Cache the currently active port and node ww names.
905 	 */
906 	cache_wwn(stor_device, vstor_packet);
907 
908 done:
909 
910 	memset(vstor_packet, 0, sizeof(struct vstor_packet));
911 	vstor_packet->operation = VSTOR_OPERATION_END_INITIALIZATION;
912 	ret = storvsc_execute_vstor_op(device, request, true);
913 	if (ret != 0)
914 		return ret;
915 
916 	if (process_sub_channels)
917 		handle_multichannel_storage(device, max_chns);
918 
919 	return ret;
920 }
921 
922 static void storvsc_handle_error(struct vmscsi_request *vm_srb,
923 				struct scsi_cmnd *scmnd,
924 				struct Scsi_Host *host,
925 				u8 asc, u8 ascq)
926 {
927 	struct storvsc_scan_work *wrk;
928 	void (*process_err_fn)(struct work_struct *work);
929 	struct hv_host_device *host_dev = shost_priv(host);
930 	bool do_work = false;
931 
932 	switch (SRB_STATUS(vm_srb->srb_status)) {
933 	case SRB_STATUS_ERROR:
934 		/*
935 		 * Let upper layer deal with error when
936 		 * sense message is present.
937 		 */
938 
939 		if (vm_srb->srb_status & SRB_STATUS_AUTOSENSE_VALID)
940 			break;
941 		/*
942 		 * If there is an error; offline the device since all
943 		 * error recovery strategies would have already been
944 		 * deployed on the host side. However, if the command
945 		 * were a pass-through command deal with it appropriately.
946 		 */
947 		switch (scmnd->cmnd[0]) {
948 		case ATA_16:
949 		case ATA_12:
950 			set_host_byte(scmnd, DID_PASSTHROUGH);
951 			break;
952 		/*
953 		 * On Some Windows hosts TEST_UNIT_READY command can return
954 		 * SRB_STATUS_ERROR, let the upper level code deal with it
955 		 * based on the sense information.
956 		 */
957 		case TEST_UNIT_READY:
958 			break;
959 		default:
960 			set_host_byte(scmnd, DID_ERROR);
961 		}
962 		break;
963 	case SRB_STATUS_INVALID_LUN:
964 		set_host_byte(scmnd, DID_NO_CONNECT);
965 		do_work = true;
966 		process_err_fn = storvsc_remove_lun;
967 		break;
968 	case SRB_STATUS_ABORTED:
969 		if (vm_srb->srb_status & SRB_STATUS_AUTOSENSE_VALID &&
970 		    (asc == 0x2a) && (ascq == 0x9)) {
971 			do_work = true;
972 			process_err_fn = storvsc_device_scan;
973 			/*
974 			 * Retry the I/O that trigerred this.
975 			 */
976 			set_host_byte(scmnd, DID_REQUEUE);
977 		}
978 		break;
979 	}
980 
981 	if (!do_work)
982 		return;
983 
984 	/*
985 	 * We need to schedule work to process this error; schedule it.
986 	 */
987 	wrk = kmalloc(sizeof(struct storvsc_scan_work), GFP_ATOMIC);
988 	if (!wrk) {
989 		set_host_byte(scmnd, DID_TARGET_FAILURE);
990 		return;
991 	}
992 
993 	wrk->host = host;
994 	wrk->lun = vm_srb->lun;
995 	wrk->tgt_id = vm_srb->target_id;
996 	INIT_WORK(&wrk->work, process_err_fn);
997 	queue_work(host_dev->handle_error_wq, &wrk->work);
998 }
999 
1000 
1001 static void storvsc_command_completion(struct storvsc_cmd_request *cmd_request,
1002 				       struct storvsc_device *stor_dev)
1003 {
1004 	struct scsi_cmnd *scmnd = cmd_request->cmd;
1005 	struct scsi_sense_hdr sense_hdr;
1006 	struct vmscsi_request *vm_srb;
1007 	u32 data_transfer_length;
1008 	struct Scsi_Host *host;
1009 	u32 payload_sz = cmd_request->payload_sz;
1010 	void *payload = cmd_request->payload;
1011 
1012 	host = stor_dev->host;
1013 
1014 	vm_srb = &cmd_request->vstor_packet.vm_srb;
1015 	data_transfer_length = vm_srb->data_transfer_length;
1016 
1017 	scmnd->result = vm_srb->scsi_status;
1018 
1019 	if (scmnd->result) {
1020 		if (scsi_normalize_sense(scmnd->sense_buffer,
1021 				SCSI_SENSE_BUFFERSIZE, &sense_hdr) &&
1022 		    !(sense_hdr.sense_key == NOT_READY &&
1023 				 sense_hdr.asc == 0x03A) &&
1024 		    do_logging(STORVSC_LOGGING_ERROR))
1025 			scsi_print_sense_hdr(scmnd->device, "storvsc",
1026 					     &sense_hdr);
1027 	}
1028 
1029 	if (vm_srb->srb_status != SRB_STATUS_SUCCESS) {
1030 		storvsc_handle_error(vm_srb, scmnd, host, sense_hdr.asc,
1031 					 sense_hdr.ascq);
1032 		/*
1033 		 * The Windows driver set data_transfer_length on
1034 		 * SRB_STATUS_DATA_OVERRUN. On other errors, this value
1035 		 * is untouched.  In these cases we set it to 0.
1036 		 */
1037 		if (vm_srb->srb_status != SRB_STATUS_DATA_OVERRUN)
1038 			data_transfer_length = 0;
1039 	}
1040 
1041 	scsi_set_resid(scmnd,
1042 		cmd_request->payload->range.len - data_transfer_length);
1043 
1044 	scmnd->scsi_done(scmnd);
1045 
1046 	if (payload_sz >
1047 		sizeof(struct vmbus_channel_packet_multipage_buffer))
1048 		kfree(payload);
1049 }
1050 
1051 static void storvsc_on_io_completion(struct storvsc_device *stor_device,
1052 				  struct vstor_packet *vstor_packet,
1053 				  struct storvsc_cmd_request *request)
1054 {
1055 	struct vstor_packet *stor_pkt;
1056 	struct hv_device *device = stor_device->device;
1057 
1058 	stor_pkt = &request->vstor_packet;
1059 
1060 	/*
1061 	 * The current SCSI handling on the host side does
1062 	 * not correctly handle:
1063 	 * INQUIRY command with page code parameter set to 0x80
1064 	 * MODE_SENSE command with cmd[2] == 0x1c
1065 	 *
1066 	 * Setup srb and scsi status so this won't be fatal.
1067 	 * We do this so we can distinguish truly fatal failues
1068 	 * (srb status == 0x4) and off-line the device in that case.
1069 	 */
1070 
1071 	if ((stor_pkt->vm_srb.cdb[0] == INQUIRY) ||
1072 	   (stor_pkt->vm_srb.cdb[0] == MODE_SENSE)) {
1073 		vstor_packet->vm_srb.scsi_status = 0;
1074 		vstor_packet->vm_srb.srb_status = SRB_STATUS_SUCCESS;
1075 	}
1076 
1077 
1078 	/* Copy over the status...etc */
1079 	stor_pkt->vm_srb.scsi_status = vstor_packet->vm_srb.scsi_status;
1080 	stor_pkt->vm_srb.srb_status = vstor_packet->vm_srb.srb_status;
1081 	stor_pkt->vm_srb.sense_info_length =
1082 	vstor_packet->vm_srb.sense_info_length;
1083 
1084 	if (vstor_packet->vm_srb.scsi_status != 0 ||
1085 	    vstor_packet->vm_srb.srb_status != SRB_STATUS_SUCCESS)
1086 		storvsc_log(device, STORVSC_LOGGING_WARN,
1087 			"cmd 0x%x scsi status 0x%x srb status 0x%x\n",
1088 			stor_pkt->vm_srb.cdb[0],
1089 			vstor_packet->vm_srb.scsi_status,
1090 			vstor_packet->vm_srb.srb_status);
1091 
1092 	if ((vstor_packet->vm_srb.scsi_status & 0xFF) == 0x02) {
1093 		/* CHECK_CONDITION */
1094 		if (vstor_packet->vm_srb.srb_status &
1095 			SRB_STATUS_AUTOSENSE_VALID) {
1096 			/* autosense data available */
1097 
1098 			storvsc_log(device, STORVSC_LOGGING_WARN,
1099 				"stor pkt %p autosense data valid - len %d\n",
1100 				request, vstor_packet->vm_srb.sense_info_length);
1101 
1102 			memcpy(request->cmd->sense_buffer,
1103 			       vstor_packet->vm_srb.sense_data,
1104 			       vstor_packet->vm_srb.sense_info_length);
1105 
1106 		}
1107 	}
1108 
1109 	stor_pkt->vm_srb.data_transfer_length =
1110 	vstor_packet->vm_srb.data_transfer_length;
1111 
1112 	storvsc_command_completion(request, stor_device);
1113 
1114 	if (atomic_dec_and_test(&stor_device->num_outstanding_req) &&
1115 		stor_device->drain_notify)
1116 		wake_up(&stor_device->waiting_to_drain);
1117 
1118 
1119 }
1120 
1121 static void storvsc_on_receive(struct storvsc_device *stor_device,
1122 			     struct vstor_packet *vstor_packet,
1123 			     struct storvsc_cmd_request *request)
1124 {
1125 	struct hv_host_device *host_dev;
1126 	switch (vstor_packet->operation) {
1127 	case VSTOR_OPERATION_COMPLETE_IO:
1128 		storvsc_on_io_completion(stor_device, vstor_packet, request);
1129 		break;
1130 
1131 	case VSTOR_OPERATION_REMOVE_DEVICE:
1132 	case VSTOR_OPERATION_ENUMERATE_BUS:
1133 		host_dev = shost_priv(stor_device->host);
1134 		queue_work(
1135 			host_dev->handle_error_wq, &host_dev->host_scan_work);
1136 		break;
1137 
1138 	case VSTOR_OPERATION_FCHBA_DATA:
1139 		cache_wwn(stor_device, vstor_packet);
1140 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
1141 		fc_host_node_name(stor_device->host) = stor_device->node_name;
1142 		fc_host_port_name(stor_device->host) = stor_device->port_name;
1143 #endif
1144 		break;
1145 	default:
1146 		break;
1147 	}
1148 }
1149 
1150 static void storvsc_on_channel_callback(void *context)
1151 {
1152 	struct vmbus_channel *channel = (struct vmbus_channel *)context;
1153 	const struct vmpacket_descriptor *desc;
1154 	struct hv_device *device;
1155 	struct storvsc_device *stor_device;
1156 
1157 	if (channel->primary_channel != NULL)
1158 		device = channel->primary_channel->device_obj;
1159 	else
1160 		device = channel->device_obj;
1161 
1162 	stor_device = get_in_stor_device(device);
1163 	if (!stor_device)
1164 		return;
1165 
1166 	foreach_vmbus_pkt(desc, channel) {
1167 		void *packet = hv_pkt_data(desc);
1168 		struct storvsc_cmd_request *request;
1169 
1170 		request = (struct storvsc_cmd_request *)
1171 			((unsigned long)desc->trans_id);
1172 
1173 		if (request == &stor_device->init_request ||
1174 		    request == &stor_device->reset_request) {
1175 			memcpy(&request->vstor_packet, packet,
1176 			       (sizeof(struct vstor_packet) - vmscsi_size_delta));
1177 			complete(&request->wait_event);
1178 		} else {
1179 			storvsc_on_receive(stor_device, packet, request);
1180 		}
1181 	}
1182 }
1183 
1184 static int storvsc_connect_to_vsp(struct hv_device *device, u32 ring_size,
1185 				  bool is_fc)
1186 {
1187 	struct vmstorage_channel_properties props;
1188 	int ret;
1189 
1190 	memset(&props, 0, sizeof(struct vmstorage_channel_properties));
1191 
1192 	ret = vmbus_open(device->channel,
1193 			 ring_size,
1194 			 ring_size,
1195 			 (void *)&props,
1196 			 sizeof(struct vmstorage_channel_properties),
1197 			 storvsc_on_channel_callback, device->channel);
1198 
1199 	if (ret != 0)
1200 		return ret;
1201 
1202 	ret = storvsc_channel_init(device, is_fc);
1203 
1204 	return ret;
1205 }
1206 
1207 static int storvsc_dev_remove(struct hv_device *device)
1208 {
1209 	struct storvsc_device *stor_device;
1210 
1211 	stor_device = hv_get_drvdata(device);
1212 
1213 	stor_device->destroy = true;
1214 
1215 	/* Make sure flag is set before waiting */
1216 	wmb();
1217 
1218 	/*
1219 	 * At this point, all outbound traffic should be disable. We
1220 	 * only allow inbound traffic (responses) to proceed so that
1221 	 * outstanding requests can be completed.
1222 	 */
1223 
1224 	storvsc_wait_to_drain(stor_device);
1225 
1226 	/*
1227 	 * Since we have already drained, we don't need to busy wait
1228 	 * as was done in final_release_stor_device()
1229 	 * Note that we cannot set the ext pointer to NULL until
1230 	 * we have drained - to drain the outgoing packets, we need to
1231 	 * allow incoming packets.
1232 	 */
1233 	hv_set_drvdata(device, NULL);
1234 
1235 	/* Close the channel */
1236 	vmbus_close(device->channel);
1237 
1238 	kfree(stor_device->stor_chns);
1239 	kfree(stor_device);
1240 	return 0;
1241 }
1242 
1243 static struct vmbus_channel *get_og_chn(struct storvsc_device *stor_device,
1244 					u16 q_num)
1245 {
1246 	u16 slot = 0;
1247 	u16 hash_qnum;
1248 	const struct cpumask *node_mask;
1249 	int num_channels, tgt_cpu;
1250 
1251 	if (stor_device->num_sc == 0)
1252 		return stor_device->device->channel;
1253 
1254 	/*
1255 	 * Our channel array is sparsley populated and we
1256 	 * initiated I/O on a processor/hw-q that does not
1257 	 * currently have a designated channel. Fix this.
1258 	 * The strategy is simple:
1259 	 * I. Ensure NUMA locality
1260 	 * II. Distribute evenly (best effort)
1261 	 * III. Mapping is persistent.
1262 	 */
1263 
1264 	node_mask = cpumask_of_node(cpu_to_node(q_num));
1265 
1266 	num_channels = 0;
1267 	for_each_cpu(tgt_cpu, &stor_device->alloced_cpus) {
1268 		if (cpumask_test_cpu(tgt_cpu, node_mask))
1269 			num_channels++;
1270 	}
1271 	if (num_channels == 0)
1272 		return stor_device->device->channel;
1273 
1274 	hash_qnum = q_num;
1275 	while (hash_qnum >= num_channels)
1276 		hash_qnum -= num_channels;
1277 
1278 	for_each_cpu(tgt_cpu, &stor_device->alloced_cpus) {
1279 		if (!cpumask_test_cpu(tgt_cpu, node_mask))
1280 			continue;
1281 		if (slot == hash_qnum)
1282 			break;
1283 		slot++;
1284 	}
1285 
1286 	stor_device->stor_chns[q_num] = stor_device->stor_chns[tgt_cpu];
1287 
1288 	return stor_device->stor_chns[q_num];
1289 }
1290 
1291 
1292 static int storvsc_do_io(struct hv_device *device,
1293 			 struct storvsc_cmd_request *request, u16 q_num)
1294 {
1295 	struct storvsc_device *stor_device;
1296 	struct vstor_packet *vstor_packet;
1297 	struct vmbus_channel *outgoing_channel, *channel;
1298 	int ret = 0;
1299 	const struct cpumask *node_mask;
1300 	int tgt_cpu;
1301 
1302 	vstor_packet = &request->vstor_packet;
1303 	stor_device = get_out_stor_device(device);
1304 
1305 	if (!stor_device)
1306 		return -ENODEV;
1307 
1308 
1309 	request->device  = device;
1310 	/*
1311 	 * Select an an appropriate channel to send the request out.
1312 	 */
1313 	if (stor_device->stor_chns[q_num] != NULL) {
1314 		outgoing_channel = stor_device->stor_chns[q_num];
1315 		if (outgoing_channel->target_cpu == q_num) {
1316 			/*
1317 			 * Ideally, we want to pick a different channel if
1318 			 * available on the same NUMA node.
1319 			 */
1320 			node_mask = cpumask_of_node(cpu_to_node(q_num));
1321 			for_each_cpu_wrap(tgt_cpu,
1322 				 &stor_device->alloced_cpus, q_num + 1) {
1323 				if (!cpumask_test_cpu(tgt_cpu, node_mask))
1324 					continue;
1325 				if (tgt_cpu == q_num)
1326 					continue;
1327 				channel = stor_device->stor_chns[tgt_cpu];
1328 				if (hv_get_avail_to_write_percent(
1329 							&channel->outbound)
1330 						> ring_avail_percent_lowater) {
1331 					outgoing_channel = channel;
1332 					goto found_channel;
1333 				}
1334 			}
1335 
1336 			/*
1337 			 * All the other channels on the same NUMA node are
1338 			 * busy. Try to use the channel on the current CPU
1339 			 */
1340 			if (hv_get_avail_to_write_percent(
1341 						&outgoing_channel->outbound)
1342 					> ring_avail_percent_lowater)
1343 				goto found_channel;
1344 
1345 			/*
1346 			 * If we reach here, all the channels on the current
1347 			 * NUMA node are busy. Try to find a channel in
1348 			 * other NUMA nodes
1349 			 */
1350 			for_each_cpu(tgt_cpu, &stor_device->alloced_cpus) {
1351 				if (cpumask_test_cpu(tgt_cpu, node_mask))
1352 					continue;
1353 				channel = stor_device->stor_chns[tgt_cpu];
1354 				if (hv_get_avail_to_write_percent(
1355 							&channel->outbound)
1356 						> ring_avail_percent_lowater) {
1357 					outgoing_channel = channel;
1358 					goto found_channel;
1359 				}
1360 			}
1361 		}
1362 	} else {
1363 		outgoing_channel = get_og_chn(stor_device, q_num);
1364 	}
1365 
1366 found_channel:
1367 	vstor_packet->flags |= REQUEST_COMPLETION_FLAG;
1368 
1369 	vstor_packet->vm_srb.length = (sizeof(struct vmscsi_request) -
1370 					vmscsi_size_delta);
1371 
1372 
1373 	vstor_packet->vm_srb.sense_info_length = sense_buffer_size;
1374 
1375 
1376 	vstor_packet->vm_srb.data_transfer_length =
1377 	request->payload->range.len;
1378 
1379 	vstor_packet->operation = VSTOR_OPERATION_EXECUTE_SRB;
1380 
1381 	if (request->payload->range.len) {
1382 
1383 		ret = vmbus_sendpacket_mpb_desc(outgoing_channel,
1384 				request->payload, request->payload_sz,
1385 				vstor_packet,
1386 				(sizeof(struct vstor_packet) -
1387 				vmscsi_size_delta),
1388 				(unsigned long)request);
1389 	} else {
1390 		ret = vmbus_sendpacket(outgoing_channel, vstor_packet,
1391 			       (sizeof(struct vstor_packet) -
1392 				vmscsi_size_delta),
1393 			       (unsigned long)request,
1394 			       VM_PKT_DATA_INBAND,
1395 			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
1396 	}
1397 
1398 	if (ret != 0)
1399 		return ret;
1400 
1401 	atomic_inc(&stor_device->num_outstanding_req);
1402 
1403 	return ret;
1404 }
1405 
1406 static int storvsc_device_alloc(struct scsi_device *sdevice)
1407 {
1408 	/*
1409 	 * Set blist flag to permit the reading of the VPD pages even when
1410 	 * the target may claim SPC-2 compliance. MSFT targets currently
1411 	 * claim SPC-2 compliance while they implement post SPC-2 features.
1412 	 * With this flag we can correctly handle WRITE_SAME_16 issues.
1413 	 *
1414 	 * Hypervisor reports SCSI_UNKNOWN type for DVD ROM device but
1415 	 * still supports REPORT LUN.
1416 	 */
1417 	sdevice->sdev_bflags = BLIST_REPORTLUN2 | BLIST_TRY_VPD_PAGES;
1418 
1419 	return 0;
1420 }
1421 
1422 static int storvsc_device_configure(struct scsi_device *sdevice)
1423 {
1424 	blk_queue_rq_timeout(sdevice->request_queue, (storvsc_timeout * HZ));
1425 
1426 	sdevice->no_write_same = 1;
1427 
1428 	/*
1429 	 * If the host is WIN8 or WIN8 R2, claim conformance to SPC-3
1430 	 * if the device is a MSFT virtual device.  If the host is
1431 	 * WIN10 or newer, allow write_same.
1432 	 */
1433 	if (!strncmp(sdevice->vendor, "Msft", 4)) {
1434 		switch (vmstor_proto_version) {
1435 		case VMSTOR_PROTO_VERSION_WIN8:
1436 		case VMSTOR_PROTO_VERSION_WIN8_1:
1437 			sdevice->scsi_level = SCSI_SPC_3;
1438 			break;
1439 		}
1440 
1441 		if (vmstor_proto_version >= VMSTOR_PROTO_VERSION_WIN10)
1442 			sdevice->no_write_same = 0;
1443 	}
1444 
1445 	return 0;
1446 }
1447 
1448 static int storvsc_get_chs(struct scsi_device *sdev, struct block_device * bdev,
1449 			   sector_t capacity, int *info)
1450 {
1451 	sector_t nsect = capacity;
1452 	sector_t cylinders = nsect;
1453 	int heads, sectors_pt;
1454 
1455 	/*
1456 	 * We are making up these values; let us keep it simple.
1457 	 */
1458 	heads = 0xff;
1459 	sectors_pt = 0x3f;      /* Sectors per track */
1460 	sector_div(cylinders, heads * sectors_pt);
1461 	if ((sector_t)(cylinders + 1) * heads * sectors_pt < nsect)
1462 		cylinders = 0xffff;
1463 
1464 	info[0] = heads;
1465 	info[1] = sectors_pt;
1466 	info[2] = (int)cylinders;
1467 
1468 	return 0;
1469 }
1470 
1471 static int storvsc_host_reset_handler(struct scsi_cmnd *scmnd)
1472 {
1473 	struct hv_host_device *host_dev = shost_priv(scmnd->device->host);
1474 	struct hv_device *device = host_dev->dev;
1475 
1476 	struct storvsc_device *stor_device;
1477 	struct storvsc_cmd_request *request;
1478 	struct vstor_packet *vstor_packet;
1479 	int ret, t;
1480 
1481 
1482 	stor_device = get_out_stor_device(device);
1483 	if (!stor_device)
1484 		return FAILED;
1485 
1486 	request = &stor_device->reset_request;
1487 	vstor_packet = &request->vstor_packet;
1488 
1489 	init_completion(&request->wait_event);
1490 
1491 	vstor_packet->operation = VSTOR_OPERATION_RESET_BUS;
1492 	vstor_packet->flags = REQUEST_COMPLETION_FLAG;
1493 	vstor_packet->vm_srb.path_id = stor_device->path_id;
1494 
1495 	ret = vmbus_sendpacket(device->channel, vstor_packet,
1496 			       (sizeof(struct vstor_packet) -
1497 				vmscsi_size_delta),
1498 			       (unsigned long)&stor_device->reset_request,
1499 			       VM_PKT_DATA_INBAND,
1500 			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
1501 	if (ret != 0)
1502 		return FAILED;
1503 
1504 	t = wait_for_completion_timeout(&request->wait_event, 5*HZ);
1505 	if (t == 0)
1506 		return TIMEOUT_ERROR;
1507 
1508 
1509 	/*
1510 	 * At this point, all outstanding requests in the adapter
1511 	 * should have been flushed out and return to us
1512 	 * There is a potential race here where the host may be in
1513 	 * the process of responding when we return from here.
1514 	 * Just wait for all in-transit packets to be accounted for
1515 	 * before we return from here.
1516 	 */
1517 	storvsc_wait_to_drain(stor_device);
1518 
1519 	return SUCCESS;
1520 }
1521 
1522 /*
1523  * The host guarantees to respond to each command, although I/O latencies might
1524  * be unbounded on Azure.  Reset the timer unconditionally to give the host a
1525  * chance to perform EH.
1526  */
1527 static enum blk_eh_timer_return storvsc_eh_timed_out(struct scsi_cmnd *scmnd)
1528 {
1529 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
1530 	if (scmnd->device->host->transportt == fc_transport_template)
1531 		return fc_eh_timed_out(scmnd);
1532 #endif
1533 	return BLK_EH_RESET_TIMER;
1534 }
1535 
1536 static bool storvsc_scsi_cmd_ok(struct scsi_cmnd *scmnd)
1537 {
1538 	bool allowed = true;
1539 	u8 scsi_op = scmnd->cmnd[0];
1540 
1541 	switch (scsi_op) {
1542 	/* the host does not handle WRITE_SAME, log accident usage */
1543 	case WRITE_SAME:
1544 	/*
1545 	 * smartd sends this command and the host does not handle
1546 	 * this. So, don't send it.
1547 	 */
1548 	case SET_WINDOW:
1549 		scmnd->result = ILLEGAL_REQUEST << 16;
1550 		allowed = false;
1551 		break;
1552 	default:
1553 		break;
1554 	}
1555 	return allowed;
1556 }
1557 
1558 static int storvsc_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *scmnd)
1559 {
1560 	int ret;
1561 	struct hv_host_device *host_dev = shost_priv(host);
1562 	struct hv_device *dev = host_dev->dev;
1563 	struct storvsc_cmd_request *cmd_request = scsi_cmd_priv(scmnd);
1564 	int i;
1565 	struct scatterlist *sgl;
1566 	unsigned int sg_count = 0;
1567 	struct vmscsi_request *vm_srb;
1568 	struct scatterlist *cur_sgl;
1569 	struct vmbus_packet_mpb_array  *payload;
1570 	u32 payload_sz;
1571 	u32 length;
1572 
1573 	if (vmstor_proto_version <= VMSTOR_PROTO_VERSION_WIN8) {
1574 		/*
1575 		 * On legacy hosts filter unimplemented commands.
1576 		 * Future hosts are expected to correctly handle
1577 		 * unsupported commands. Furthermore, it is
1578 		 * possible that some of the currently
1579 		 * unsupported commands maybe supported in
1580 		 * future versions of the host.
1581 		 */
1582 		if (!storvsc_scsi_cmd_ok(scmnd)) {
1583 			scmnd->scsi_done(scmnd);
1584 			return 0;
1585 		}
1586 	}
1587 
1588 	/* Setup the cmd request */
1589 	cmd_request->cmd = scmnd;
1590 
1591 	vm_srb = &cmd_request->vstor_packet.vm_srb;
1592 	vm_srb->win8_extension.time_out_value = 60;
1593 
1594 	vm_srb->win8_extension.srb_flags |=
1595 		SRB_FLAGS_DISABLE_SYNCH_TRANSFER;
1596 
1597 	if (scmnd->device->tagged_supported) {
1598 		vm_srb->win8_extension.srb_flags |=
1599 		(SRB_FLAGS_QUEUE_ACTION_ENABLE | SRB_FLAGS_NO_QUEUE_FREEZE);
1600 		vm_srb->win8_extension.queue_tag = SP_UNTAGGED;
1601 		vm_srb->win8_extension.queue_action = SRB_SIMPLE_TAG_REQUEST;
1602 	}
1603 
1604 	/* Build the SRB */
1605 	switch (scmnd->sc_data_direction) {
1606 	case DMA_TO_DEVICE:
1607 		vm_srb->data_in = WRITE_TYPE;
1608 		vm_srb->win8_extension.srb_flags |= SRB_FLAGS_DATA_OUT;
1609 		break;
1610 	case DMA_FROM_DEVICE:
1611 		vm_srb->data_in = READ_TYPE;
1612 		vm_srb->win8_extension.srb_flags |= SRB_FLAGS_DATA_IN;
1613 		break;
1614 	case DMA_NONE:
1615 		vm_srb->data_in = UNKNOWN_TYPE;
1616 		vm_srb->win8_extension.srb_flags |= SRB_FLAGS_NO_DATA_TRANSFER;
1617 		break;
1618 	default:
1619 		/*
1620 		 * This is DMA_BIDIRECTIONAL or something else we are never
1621 		 * supposed to see here.
1622 		 */
1623 		WARN(1, "Unexpected data direction: %d\n",
1624 		     scmnd->sc_data_direction);
1625 		return -EINVAL;
1626 	}
1627 
1628 
1629 	vm_srb->port_number = host_dev->port;
1630 	vm_srb->path_id = scmnd->device->channel;
1631 	vm_srb->target_id = scmnd->device->id;
1632 	vm_srb->lun = scmnd->device->lun;
1633 
1634 	vm_srb->cdb_length = scmnd->cmd_len;
1635 
1636 	memcpy(vm_srb->cdb, scmnd->cmnd, vm_srb->cdb_length);
1637 
1638 	sgl = (struct scatterlist *)scsi_sglist(scmnd);
1639 	sg_count = scsi_sg_count(scmnd);
1640 
1641 	length = scsi_bufflen(scmnd);
1642 	payload = (struct vmbus_packet_mpb_array *)&cmd_request->mpb;
1643 	payload_sz = sizeof(cmd_request->mpb);
1644 
1645 	if (sg_count) {
1646 		if (sg_count > MAX_PAGE_BUFFER_COUNT) {
1647 
1648 			payload_sz = (sg_count * sizeof(u64) +
1649 				      sizeof(struct vmbus_packet_mpb_array));
1650 			payload = kzalloc(payload_sz, GFP_ATOMIC);
1651 			if (!payload)
1652 				return SCSI_MLQUEUE_DEVICE_BUSY;
1653 		}
1654 
1655 		payload->range.len = length;
1656 		payload->range.offset = sgl[0].offset;
1657 
1658 		cur_sgl = sgl;
1659 		for (i = 0; i < sg_count; i++) {
1660 			payload->range.pfn_array[i] =
1661 				page_to_pfn(sg_page((cur_sgl)));
1662 			cur_sgl = sg_next(cur_sgl);
1663 		}
1664 	}
1665 
1666 	cmd_request->payload = payload;
1667 	cmd_request->payload_sz = payload_sz;
1668 
1669 	/* Invokes the vsc to start an IO */
1670 	ret = storvsc_do_io(dev, cmd_request, get_cpu());
1671 	put_cpu();
1672 
1673 	if (ret == -EAGAIN) {
1674 		if (payload_sz > sizeof(cmd_request->mpb))
1675 			kfree(payload);
1676 		/* no more space */
1677 		return SCSI_MLQUEUE_DEVICE_BUSY;
1678 	}
1679 
1680 	return 0;
1681 }
1682 
1683 static struct scsi_host_template scsi_driver = {
1684 	.module	=		THIS_MODULE,
1685 	.name =			"storvsc_host_t",
1686 	.cmd_size =             sizeof(struct storvsc_cmd_request),
1687 	.bios_param =		storvsc_get_chs,
1688 	.queuecommand =		storvsc_queuecommand,
1689 	.eh_host_reset_handler =	storvsc_host_reset_handler,
1690 	.proc_name =		"storvsc_host",
1691 	.eh_timed_out =		storvsc_eh_timed_out,
1692 	.slave_alloc =		storvsc_device_alloc,
1693 	.slave_configure =	storvsc_device_configure,
1694 	.cmd_per_lun =		2048,
1695 	.this_id =		-1,
1696 	/* Make sure we dont get a sg segment crosses a page boundary */
1697 	.dma_boundary =		PAGE_SIZE-1,
1698 	/* Ensure there are no gaps in presented sgls */
1699 	.virt_boundary_mask =	PAGE_SIZE-1,
1700 	.no_write_same =	1,
1701 	.track_queue_depth =	1,
1702 	.change_queue_depth =	storvsc_change_queue_depth,
1703 };
1704 
1705 enum {
1706 	SCSI_GUID,
1707 	IDE_GUID,
1708 	SFC_GUID,
1709 };
1710 
1711 static const struct hv_vmbus_device_id id_table[] = {
1712 	/* SCSI guid */
1713 	{ HV_SCSI_GUID,
1714 	  .driver_data = SCSI_GUID
1715 	},
1716 	/* IDE guid */
1717 	{ HV_IDE_GUID,
1718 	  .driver_data = IDE_GUID
1719 	},
1720 	/* Fibre Channel GUID */
1721 	{
1722 	  HV_SYNTHFC_GUID,
1723 	  .driver_data = SFC_GUID
1724 	},
1725 	{ },
1726 };
1727 
1728 MODULE_DEVICE_TABLE(vmbus, id_table);
1729 
1730 static int storvsc_probe(struct hv_device *device,
1731 			const struct hv_vmbus_device_id *dev_id)
1732 {
1733 	int ret;
1734 	int num_cpus = num_online_cpus();
1735 	struct Scsi_Host *host;
1736 	struct hv_host_device *host_dev;
1737 	bool dev_is_ide = ((dev_id->driver_data == IDE_GUID) ? true : false);
1738 	bool is_fc = ((dev_id->driver_data == SFC_GUID) ? true : false);
1739 	int target = 0;
1740 	struct storvsc_device *stor_device;
1741 	int max_luns_per_target;
1742 	int max_targets;
1743 	int max_channels;
1744 	int max_sub_channels = 0;
1745 
1746 	/*
1747 	 * Based on the windows host we are running on,
1748 	 * set state to properly communicate with the host.
1749 	 */
1750 
1751 	if (vmbus_proto_version < VERSION_WIN8) {
1752 		max_luns_per_target = STORVSC_IDE_MAX_LUNS_PER_TARGET;
1753 		max_targets = STORVSC_IDE_MAX_TARGETS;
1754 		max_channels = STORVSC_IDE_MAX_CHANNELS;
1755 	} else {
1756 		max_luns_per_target = STORVSC_MAX_LUNS_PER_TARGET;
1757 		max_targets = STORVSC_MAX_TARGETS;
1758 		max_channels = STORVSC_MAX_CHANNELS;
1759 		/*
1760 		 * On Windows8 and above, we support sub-channels for storage
1761 		 * on SCSI and FC controllers.
1762 		 * The number of sub-channels offerred is based on the number of
1763 		 * VCPUs in the guest.
1764 		 */
1765 		if (!dev_is_ide)
1766 			max_sub_channels =
1767 				(num_cpus - 1) / storvsc_vcpus_per_sub_channel;
1768 	}
1769 
1770 	scsi_driver.can_queue = max_outstanding_req_per_channel *
1771 				(max_sub_channels + 1) *
1772 				(100 - ring_avail_percent_lowater) / 100;
1773 
1774 	host = scsi_host_alloc(&scsi_driver,
1775 			       sizeof(struct hv_host_device));
1776 	if (!host)
1777 		return -ENOMEM;
1778 
1779 	host_dev = shost_priv(host);
1780 	memset(host_dev, 0, sizeof(struct hv_host_device));
1781 
1782 	host_dev->port = host->host_no;
1783 	host_dev->dev = device;
1784 	host_dev->host = host;
1785 
1786 
1787 	stor_device = kzalloc(sizeof(struct storvsc_device), GFP_KERNEL);
1788 	if (!stor_device) {
1789 		ret = -ENOMEM;
1790 		goto err_out0;
1791 	}
1792 
1793 	stor_device->destroy = false;
1794 	init_waitqueue_head(&stor_device->waiting_to_drain);
1795 	stor_device->device = device;
1796 	stor_device->host = host;
1797 	hv_set_drvdata(device, stor_device);
1798 
1799 	stor_device->port_number = host->host_no;
1800 	ret = storvsc_connect_to_vsp(device, storvsc_ringbuffer_size, is_fc);
1801 	if (ret)
1802 		goto err_out1;
1803 
1804 	host_dev->path = stor_device->path_id;
1805 	host_dev->target = stor_device->target_id;
1806 
1807 	switch (dev_id->driver_data) {
1808 	case SFC_GUID:
1809 		host->max_lun = STORVSC_FC_MAX_LUNS_PER_TARGET;
1810 		host->max_id = STORVSC_FC_MAX_TARGETS;
1811 		host->max_channel = STORVSC_FC_MAX_CHANNELS - 1;
1812 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
1813 		host->transportt = fc_transport_template;
1814 #endif
1815 		break;
1816 
1817 	case SCSI_GUID:
1818 		host->max_lun = max_luns_per_target;
1819 		host->max_id = max_targets;
1820 		host->max_channel = max_channels - 1;
1821 		break;
1822 
1823 	default:
1824 		host->max_lun = STORVSC_IDE_MAX_LUNS_PER_TARGET;
1825 		host->max_id = STORVSC_IDE_MAX_TARGETS;
1826 		host->max_channel = STORVSC_IDE_MAX_CHANNELS - 1;
1827 		break;
1828 	}
1829 	/* max cmd length */
1830 	host->max_cmd_len = STORVSC_MAX_CMD_LEN;
1831 
1832 	/*
1833 	 * set the table size based on the info we got
1834 	 * from the host.
1835 	 */
1836 	host->sg_tablesize = (stor_device->max_transfer_bytes >> PAGE_SHIFT);
1837 	/*
1838 	 * Set the number of HW queues we are supporting.
1839 	 */
1840 	if (stor_device->num_sc != 0)
1841 		host->nr_hw_queues = stor_device->num_sc + 1;
1842 
1843 	/*
1844 	 * Set the error handler work queue.
1845 	 */
1846 	host_dev->handle_error_wq =
1847 			alloc_ordered_workqueue("storvsc_error_wq_%d",
1848 						WQ_MEM_RECLAIM,
1849 						host->host_no);
1850 	if (!host_dev->handle_error_wq)
1851 		goto err_out2;
1852 	INIT_WORK(&host_dev->host_scan_work, storvsc_host_scan);
1853 	/* Register the HBA and start the scsi bus scan */
1854 	ret = scsi_add_host(host, &device->device);
1855 	if (ret != 0)
1856 		goto err_out3;
1857 
1858 	if (!dev_is_ide) {
1859 		scsi_scan_host(host);
1860 	} else {
1861 		target = (device->dev_instance.b[5] << 8 |
1862 			 device->dev_instance.b[4]);
1863 		ret = scsi_add_device(host, 0, target, 0);
1864 		if (ret)
1865 			goto err_out4;
1866 	}
1867 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
1868 	if (host->transportt == fc_transport_template) {
1869 		struct fc_rport_identifiers ids = {
1870 			.roles = FC_PORT_ROLE_FCP_DUMMY_INITIATOR,
1871 		};
1872 
1873 		fc_host_node_name(host) = stor_device->node_name;
1874 		fc_host_port_name(host) = stor_device->port_name;
1875 		stor_device->rport = fc_remote_port_add(host, 0, &ids);
1876 		if (!stor_device->rport) {
1877 			ret = -ENOMEM;
1878 			goto err_out4;
1879 		}
1880 	}
1881 #endif
1882 	return 0;
1883 
1884 err_out4:
1885 	scsi_remove_host(host);
1886 
1887 err_out3:
1888 	destroy_workqueue(host_dev->handle_error_wq);
1889 
1890 err_out2:
1891 	/*
1892 	 * Once we have connected with the host, we would need to
1893 	 * to invoke storvsc_dev_remove() to rollback this state and
1894 	 * this call also frees up the stor_device; hence the jump around
1895 	 * err_out1 label.
1896 	 */
1897 	storvsc_dev_remove(device);
1898 	goto err_out0;
1899 
1900 err_out1:
1901 	kfree(stor_device->stor_chns);
1902 	kfree(stor_device);
1903 
1904 err_out0:
1905 	scsi_host_put(host);
1906 	return ret;
1907 }
1908 
1909 /* Change a scsi target's queue depth */
1910 static int storvsc_change_queue_depth(struct scsi_device *sdev, int queue_depth)
1911 {
1912 	if (queue_depth > scsi_driver.can_queue)
1913 		queue_depth = scsi_driver.can_queue;
1914 
1915 	return scsi_change_queue_depth(sdev, queue_depth);
1916 }
1917 
1918 static int storvsc_remove(struct hv_device *dev)
1919 {
1920 	struct storvsc_device *stor_device = hv_get_drvdata(dev);
1921 	struct Scsi_Host *host = stor_device->host;
1922 	struct hv_host_device *host_dev = shost_priv(host);
1923 
1924 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
1925 	if (host->transportt == fc_transport_template) {
1926 		fc_remote_port_delete(stor_device->rport);
1927 		fc_remove_host(host);
1928 	}
1929 #endif
1930 	destroy_workqueue(host_dev->handle_error_wq);
1931 	scsi_remove_host(host);
1932 	storvsc_dev_remove(dev);
1933 	scsi_host_put(host);
1934 
1935 	return 0;
1936 }
1937 
1938 static struct hv_driver storvsc_drv = {
1939 	.name = KBUILD_MODNAME,
1940 	.id_table = id_table,
1941 	.probe = storvsc_probe,
1942 	.remove = storvsc_remove,
1943 	.driver = {
1944 		.probe_type = PROBE_PREFER_ASYNCHRONOUS,
1945 	},
1946 };
1947 
1948 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
1949 static struct fc_function_template fc_transport_functions = {
1950 	.show_host_node_name = 1,
1951 	.show_host_port_name = 1,
1952 };
1953 #endif
1954 
1955 static int __init storvsc_drv_init(void)
1956 {
1957 	int ret;
1958 
1959 	/*
1960 	 * Divide the ring buffer data size (which is 1 page less
1961 	 * than the ring buffer size since that page is reserved for
1962 	 * the ring buffer indices) by the max request size (which is
1963 	 * vmbus_channel_packet_multipage_buffer + struct vstor_packet + u64)
1964 	 */
1965 	max_outstanding_req_per_channel =
1966 		((storvsc_ringbuffer_size - PAGE_SIZE) /
1967 		ALIGN(MAX_MULTIPAGE_BUFFER_PACKET +
1968 		sizeof(struct vstor_packet) + sizeof(u64) -
1969 		vmscsi_size_delta,
1970 		sizeof(u64)));
1971 
1972 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
1973 	fc_transport_template = fc_attach_transport(&fc_transport_functions);
1974 	if (!fc_transport_template)
1975 		return -ENODEV;
1976 #endif
1977 
1978 	ret = vmbus_driver_register(&storvsc_drv);
1979 
1980 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
1981 	if (ret)
1982 		fc_release_transport(fc_transport_template);
1983 #endif
1984 
1985 	return ret;
1986 }
1987 
1988 static void __exit storvsc_drv_exit(void)
1989 {
1990 	vmbus_driver_unregister(&storvsc_drv);
1991 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
1992 	fc_release_transport(fc_transport_template);
1993 #endif
1994 }
1995 
1996 MODULE_LICENSE("GPL");
1997 MODULE_DESCRIPTION("Microsoft Hyper-V virtual storage driver");
1998 module_init(storvsc_drv_init);
1999 module_exit(storvsc_drv_exit);
2000