xref: /linux/drivers/scsi/storvsc_drv.c (revision 8f8d5745bb520c76b81abef4a2cb3023d0313bfd)
1 /*
2  * Copyright (c) 2009, Microsoft Corporation.
3  *
4  * This program is free software; you can redistribute it and/or modify it
5  * under the terms and conditions of the GNU General Public License,
6  * version 2, as published by the Free Software Foundation.
7  *
8  * This program is distributed in the hope it will be useful, but WITHOUT
9  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
10  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
11  * more details.
12  *
13  * You should have received a copy of the GNU General Public License along with
14  * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
15  * Place - Suite 330, Boston, MA 02111-1307 USA.
16  *
17  * Authors:
18  *   Haiyang Zhang <haiyangz@microsoft.com>
19  *   Hank Janssen  <hjanssen@microsoft.com>
20  *   K. Y. Srinivasan <kys@microsoft.com>
21  */
22 
23 #include <linux/kernel.h>
24 #include <linux/wait.h>
25 #include <linux/sched.h>
26 #include <linux/completion.h>
27 #include <linux/string.h>
28 #include <linux/mm.h>
29 #include <linux/delay.h>
30 #include <linux/init.h>
31 #include <linux/slab.h>
32 #include <linux/module.h>
33 #include <linux/device.h>
34 #include <linux/hyperv.h>
35 #include <linux/blkdev.h>
36 #include <scsi/scsi.h>
37 #include <scsi/scsi_cmnd.h>
38 #include <scsi/scsi_host.h>
39 #include <scsi/scsi_device.h>
40 #include <scsi/scsi_tcq.h>
41 #include <scsi/scsi_eh.h>
42 #include <scsi/scsi_devinfo.h>
43 #include <scsi/scsi_dbg.h>
44 #include <scsi/scsi_transport_fc.h>
45 #include <scsi/scsi_transport.h>
46 
47 /*
48  * All wire protocol details (storage protocol between the guest and the host)
49  * are consolidated here.
50  *
51  * Begin protocol definitions.
52  */
53 
54 /*
55  * Version history:
56  * V1 Beta: 0.1
57  * V1 RC < 2008/1/31: 1.0
58  * V1 RC > 2008/1/31:  2.0
59  * Win7: 4.2
60  * Win8: 5.1
61  * Win8.1: 6.0
62  * Win10: 6.2
63  */
64 
65 #define VMSTOR_PROTO_VERSION(MAJOR_, MINOR_)	((((MAJOR_) & 0xff) << 8) | \
66 						(((MINOR_) & 0xff)))
67 
68 #define VMSTOR_PROTO_VERSION_WIN6	VMSTOR_PROTO_VERSION(2, 0)
69 #define VMSTOR_PROTO_VERSION_WIN7	VMSTOR_PROTO_VERSION(4, 2)
70 #define VMSTOR_PROTO_VERSION_WIN8	VMSTOR_PROTO_VERSION(5, 1)
71 #define VMSTOR_PROTO_VERSION_WIN8_1	VMSTOR_PROTO_VERSION(6, 0)
72 #define VMSTOR_PROTO_VERSION_WIN10	VMSTOR_PROTO_VERSION(6, 2)
73 
74 /*  Packet structure describing virtual storage requests. */
75 enum vstor_packet_operation {
76 	VSTOR_OPERATION_COMPLETE_IO		= 1,
77 	VSTOR_OPERATION_REMOVE_DEVICE		= 2,
78 	VSTOR_OPERATION_EXECUTE_SRB		= 3,
79 	VSTOR_OPERATION_RESET_LUN		= 4,
80 	VSTOR_OPERATION_RESET_ADAPTER		= 5,
81 	VSTOR_OPERATION_RESET_BUS		= 6,
82 	VSTOR_OPERATION_BEGIN_INITIALIZATION	= 7,
83 	VSTOR_OPERATION_END_INITIALIZATION	= 8,
84 	VSTOR_OPERATION_QUERY_PROTOCOL_VERSION	= 9,
85 	VSTOR_OPERATION_QUERY_PROPERTIES	= 10,
86 	VSTOR_OPERATION_ENUMERATE_BUS		= 11,
87 	VSTOR_OPERATION_FCHBA_DATA              = 12,
88 	VSTOR_OPERATION_CREATE_SUB_CHANNELS     = 13,
89 	VSTOR_OPERATION_MAXIMUM                 = 13
90 };
91 
92 /*
93  * WWN packet for Fibre Channel HBA
94  */
95 
96 struct hv_fc_wwn_packet {
97 	u8	primary_active;
98 	u8	reserved1[3];
99 	u8	primary_port_wwn[8];
100 	u8	primary_node_wwn[8];
101 	u8	secondary_port_wwn[8];
102 	u8	secondary_node_wwn[8];
103 };
104 
105 
106 
107 /*
108  * SRB Flag Bits
109  */
110 
111 #define SRB_FLAGS_QUEUE_ACTION_ENABLE		0x00000002
112 #define SRB_FLAGS_DISABLE_DISCONNECT		0x00000004
113 #define SRB_FLAGS_DISABLE_SYNCH_TRANSFER	0x00000008
114 #define SRB_FLAGS_BYPASS_FROZEN_QUEUE		0x00000010
115 #define SRB_FLAGS_DISABLE_AUTOSENSE		0x00000020
116 #define SRB_FLAGS_DATA_IN			0x00000040
117 #define SRB_FLAGS_DATA_OUT			0x00000080
118 #define SRB_FLAGS_NO_DATA_TRANSFER		0x00000000
119 #define SRB_FLAGS_UNSPECIFIED_DIRECTION	(SRB_FLAGS_DATA_IN | SRB_FLAGS_DATA_OUT)
120 #define SRB_FLAGS_NO_QUEUE_FREEZE		0x00000100
121 #define SRB_FLAGS_ADAPTER_CACHE_ENABLE		0x00000200
122 #define SRB_FLAGS_FREE_SENSE_BUFFER		0x00000400
123 
124 /*
125  * This flag indicates the request is part of the workflow for processing a D3.
126  */
127 #define SRB_FLAGS_D3_PROCESSING			0x00000800
128 #define SRB_FLAGS_IS_ACTIVE			0x00010000
129 #define SRB_FLAGS_ALLOCATED_FROM_ZONE		0x00020000
130 #define SRB_FLAGS_SGLIST_FROM_POOL		0x00040000
131 #define SRB_FLAGS_BYPASS_LOCKED_QUEUE		0x00080000
132 #define SRB_FLAGS_NO_KEEP_AWAKE			0x00100000
133 #define SRB_FLAGS_PORT_DRIVER_ALLOCSENSE	0x00200000
134 #define SRB_FLAGS_PORT_DRIVER_SENSEHASPORT	0x00400000
135 #define SRB_FLAGS_DONT_START_NEXT_PACKET	0x00800000
136 #define SRB_FLAGS_PORT_DRIVER_RESERVED		0x0F000000
137 #define SRB_FLAGS_CLASS_DRIVER_RESERVED		0xF0000000
138 
139 #define SP_UNTAGGED			((unsigned char) ~0)
140 #define SRB_SIMPLE_TAG_REQUEST		0x20
141 
142 /*
143  * Platform neutral description of a scsi request -
144  * this remains the same across the write regardless of 32/64 bit
145  * note: it's patterned off the SCSI_PASS_THROUGH structure
146  */
147 #define STORVSC_MAX_CMD_LEN			0x10
148 
149 #define POST_WIN7_STORVSC_SENSE_BUFFER_SIZE	0x14
150 #define PRE_WIN8_STORVSC_SENSE_BUFFER_SIZE	0x12
151 
152 #define STORVSC_SENSE_BUFFER_SIZE		0x14
153 #define STORVSC_MAX_BUF_LEN_WITH_PADDING	0x14
154 
155 /*
156  * Sense buffer size changed in win8; have a run-time
157  * variable to track the size we should use.  This value will
158  * likely change during protocol negotiation but it is valid
159  * to start by assuming pre-Win8.
160  */
161 static int sense_buffer_size = PRE_WIN8_STORVSC_SENSE_BUFFER_SIZE;
162 
163 /*
164  * The storage protocol version is determined during the
165  * initial exchange with the host.  It will indicate which
166  * storage functionality is available in the host.
167 */
168 static int vmstor_proto_version;
169 
170 #define STORVSC_LOGGING_NONE	0
171 #define STORVSC_LOGGING_ERROR	1
172 #define STORVSC_LOGGING_WARN	2
173 
174 static int logging_level = STORVSC_LOGGING_ERROR;
175 module_param(logging_level, int, S_IRUGO|S_IWUSR);
176 MODULE_PARM_DESC(logging_level,
177 	"Logging level, 0 - None, 1 - Error (default), 2 - Warning.");
178 
179 static inline bool do_logging(int level)
180 {
181 	return logging_level >= level;
182 }
183 
184 #define storvsc_log(dev, level, fmt, ...)			\
185 do {								\
186 	if (do_logging(level))					\
187 		dev_warn(&(dev)->device, fmt, ##__VA_ARGS__);	\
188 } while (0)
189 
190 struct vmscsi_win8_extension {
191 	/*
192 	 * The following were added in Windows 8
193 	 */
194 	u16 reserve;
195 	u8  queue_tag;
196 	u8  queue_action;
197 	u32 srb_flags;
198 	u32 time_out_value;
199 	u32 queue_sort_ey;
200 } __packed;
201 
202 struct vmscsi_request {
203 	u16 length;
204 	u8 srb_status;
205 	u8 scsi_status;
206 
207 	u8  port_number;
208 	u8  path_id;
209 	u8  target_id;
210 	u8  lun;
211 
212 	u8  cdb_length;
213 	u8  sense_info_length;
214 	u8  data_in;
215 	u8  reserved;
216 
217 	u32 data_transfer_length;
218 
219 	union {
220 		u8 cdb[STORVSC_MAX_CMD_LEN];
221 		u8 sense_data[STORVSC_SENSE_BUFFER_SIZE];
222 		u8 reserved_array[STORVSC_MAX_BUF_LEN_WITH_PADDING];
223 	};
224 	/*
225 	 * The following was added in win8.
226 	 */
227 	struct vmscsi_win8_extension win8_extension;
228 
229 } __attribute((packed));
230 
231 
232 /*
233  * The size of the vmscsi_request has changed in win8. The
234  * additional size is because of new elements added to the
235  * structure. These elements are valid only when we are talking
236  * to a win8 host.
237  * Track the correction to size we need to apply. This value
238  * will likely change during protocol negotiation but it is
239  * valid to start by assuming pre-Win8.
240  */
241 static int vmscsi_size_delta = sizeof(struct vmscsi_win8_extension);
242 
243 /*
244  * The list of storage protocols in order of preference.
245  */
246 struct vmstor_protocol {
247 	int protocol_version;
248 	int sense_buffer_size;
249 	int vmscsi_size_delta;
250 };
251 
252 
253 static const struct vmstor_protocol vmstor_protocols[] = {
254 	{
255 		VMSTOR_PROTO_VERSION_WIN10,
256 		POST_WIN7_STORVSC_SENSE_BUFFER_SIZE,
257 		0
258 	},
259 	{
260 		VMSTOR_PROTO_VERSION_WIN8_1,
261 		POST_WIN7_STORVSC_SENSE_BUFFER_SIZE,
262 		0
263 	},
264 	{
265 		VMSTOR_PROTO_VERSION_WIN8,
266 		POST_WIN7_STORVSC_SENSE_BUFFER_SIZE,
267 		0
268 	},
269 	{
270 		VMSTOR_PROTO_VERSION_WIN7,
271 		PRE_WIN8_STORVSC_SENSE_BUFFER_SIZE,
272 		sizeof(struct vmscsi_win8_extension),
273 	},
274 	{
275 		VMSTOR_PROTO_VERSION_WIN6,
276 		PRE_WIN8_STORVSC_SENSE_BUFFER_SIZE,
277 		sizeof(struct vmscsi_win8_extension),
278 	}
279 };
280 
281 
282 /*
283  * This structure is sent during the initialization phase to get the different
284  * properties of the channel.
285  */
286 
287 #define STORAGE_CHANNEL_SUPPORTS_MULTI_CHANNEL		0x1
288 
289 struct vmstorage_channel_properties {
290 	u32 reserved;
291 	u16 max_channel_cnt;
292 	u16 reserved1;
293 
294 	u32 flags;
295 	u32   max_transfer_bytes;
296 
297 	u64  reserved2;
298 } __packed;
299 
300 /*  This structure is sent during the storage protocol negotiations. */
301 struct vmstorage_protocol_version {
302 	/* Major (MSW) and minor (LSW) version numbers. */
303 	u16 major_minor;
304 
305 	/*
306 	 * Revision number is auto-incremented whenever this file is changed
307 	 * (See FILL_VMSTOR_REVISION macro above).  Mismatch does not
308 	 * definitely indicate incompatibility--but it does indicate mismatched
309 	 * builds.
310 	 * This is only used on the windows side. Just set it to 0.
311 	 */
312 	u16 revision;
313 } __packed;
314 
315 /* Channel Property Flags */
316 #define STORAGE_CHANNEL_REMOVABLE_FLAG		0x1
317 #define STORAGE_CHANNEL_EMULATED_IDE_FLAG	0x2
318 
319 struct vstor_packet {
320 	/* Requested operation type */
321 	enum vstor_packet_operation operation;
322 
323 	/*  Flags - see below for values */
324 	u32 flags;
325 
326 	/* Status of the request returned from the server side. */
327 	u32 status;
328 
329 	/* Data payload area */
330 	union {
331 		/*
332 		 * Structure used to forward SCSI commands from the
333 		 * client to the server.
334 		 */
335 		struct vmscsi_request vm_srb;
336 
337 		/* Structure used to query channel properties. */
338 		struct vmstorage_channel_properties storage_channel_properties;
339 
340 		/* Used during version negotiations. */
341 		struct vmstorage_protocol_version version;
342 
343 		/* Fibre channel address packet */
344 		struct hv_fc_wwn_packet wwn_packet;
345 
346 		/* Number of sub-channels to create */
347 		u16 sub_channel_count;
348 
349 		/* This will be the maximum of the union members */
350 		u8  buffer[0x34];
351 	};
352 } __packed;
353 
354 /*
355  * Packet Flags:
356  *
357  * This flag indicates that the server should send back a completion for this
358  * packet.
359  */
360 
361 #define REQUEST_COMPLETION_FLAG	0x1
362 
363 /* Matches Windows-end */
364 enum storvsc_request_type {
365 	WRITE_TYPE = 0,
366 	READ_TYPE,
367 	UNKNOWN_TYPE,
368 };
369 
370 /*
371  * SRB status codes and masks; a subset of the codes used here.
372  */
373 
374 #define SRB_STATUS_AUTOSENSE_VALID	0x80
375 #define SRB_STATUS_QUEUE_FROZEN		0x40
376 #define SRB_STATUS_INVALID_LUN	0x20
377 #define SRB_STATUS_SUCCESS	0x01
378 #define SRB_STATUS_ABORTED	0x02
379 #define SRB_STATUS_ERROR	0x04
380 #define SRB_STATUS_DATA_OVERRUN	0x12
381 
382 #define SRB_STATUS(status) \
383 	(status & ~(SRB_STATUS_AUTOSENSE_VALID | SRB_STATUS_QUEUE_FROZEN))
384 /*
385  * This is the end of Protocol specific defines.
386  */
387 
388 static int storvsc_ringbuffer_size = (128 * 1024);
389 static u32 max_outstanding_req_per_channel;
390 
391 static int storvsc_vcpus_per_sub_channel = 4;
392 
393 module_param(storvsc_ringbuffer_size, int, S_IRUGO);
394 MODULE_PARM_DESC(storvsc_ringbuffer_size, "Ring buffer size (bytes)");
395 
396 module_param(storvsc_vcpus_per_sub_channel, int, S_IRUGO);
397 MODULE_PARM_DESC(storvsc_vcpus_per_sub_channel, "Ratio of VCPUs to subchannels");
398 
399 static int ring_avail_percent_lowater = 10;
400 module_param(ring_avail_percent_lowater, int, S_IRUGO);
401 MODULE_PARM_DESC(ring_avail_percent_lowater,
402 		"Select a channel if available ring size > this in percent");
403 
404 /*
405  * Timeout in seconds for all devices managed by this driver.
406  */
407 static int storvsc_timeout = 180;
408 
409 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
410 static struct scsi_transport_template *fc_transport_template;
411 #endif
412 
413 static void storvsc_on_channel_callback(void *context);
414 
415 #define STORVSC_MAX_LUNS_PER_TARGET			255
416 #define STORVSC_MAX_TARGETS				2
417 #define STORVSC_MAX_CHANNELS				8
418 
419 #define STORVSC_FC_MAX_LUNS_PER_TARGET			255
420 #define STORVSC_FC_MAX_TARGETS				128
421 #define STORVSC_FC_MAX_CHANNELS				8
422 
423 #define STORVSC_IDE_MAX_LUNS_PER_TARGET			64
424 #define STORVSC_IDE_MAX_TARGETS				1
425 #define STORVSC_IDE_MAX_CHANNELS			1
426 
427 struct storvsc_cmd_request {
428 	struct scsi_cmnd *cmd;
429 
430 	struct hv_device *device;
431 
432 	/* Synchronize the request/response if needed */
433 	struct completion wait_event;
434 
435 	struct vmbus_channel_packet_multipage_buffer mpb;
436 	struct vmbus_packet_mpb_array *payload;
437 	u32 payload_sz;
438 
439 	struct vstor_packet vstor_packet;
440 };
441 
442 
443 /* A storvsc device is a device object that contains a vmbus channel */
444 struct storvsc_device {
445 	struct hv_device *device;
446 
447 	bool	 destroy;
448 	bool	 drain_notify;
449 	atomic_t num_outstanding_req;
450 	struct Scsi_Host *host;
451 
452 	wait_queue_head_t waiting_to_drain;
453 
454 	/*
455 	 * Each unique Port/Path/Target represents 1 channel ie scsi
456 	 * controller. In reality, the pathid, targetid is always 0
457 	 * and the port is set by us
458 	 */
459 	unsigned int port_number;
460 	unsigned char path_id;
461 	unsigned char target_id;
462 
463 	/*
464 	 * Max I/O, the device can support.
465 	 */
466 	u32   max_transfer_bytes;
467 	/*
468 	 * Number of sub-channels we will open.
469 	 */
470 	u16 num_sc;
471 	struct vmbus_channel **stor_chns;
472 	/*
473 	 * Mask of CPUs bound to subchannels.
474 	 */
475 	struct cpumask alloced_cpus;
476 	/* Used for vsc/vsp channel reset process */
477 	struct storvsc_cmd_request init_request;
478 	struct storvsc_cmd_request reset_request;
479 	/*
480 	 * Currently active port and node names for FC devices.
481 	 */
482 	u64 node_name;
483 	u64 port_name;
484 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
485 	struct fc_rport *rport;
486 #endif
487 };
488 
489 struct hv_host_device {
490 	struct hv_device *dev;
491 	unsigned int port;
492 	unsigned char path;
493 	unsigned char target;
494 	struct workqueue_struct *handle_error_wq;
495 	struct work_struct host_scan_work;
496 	struct Scsi_Host *host;
497 };
498 
499 struct storvsc_scan_work {
500 	struct work_struct work;
501 	struct Scsi_Host *host;
502 	u8 lun;
503 	u8 tgt_id;
504 };
505 
506 static void storvsc_device_scan(struct work_struct *work)
507 {
508 	struct storvsc_scan_work *wrk;
509 	struct scsi_device *sdev;
510 
511 	wrk = container_of(work, struct storvsc_scan_work, work);
512 
513 	sdev = scsi_device_lookup(wrk->host, 0, wrk->tgt_id, wrk->lun);
514 	if (!sdev)
515 		goto done;
516 	scsi_rescan_device(&sdev->sdev_gendev);
517 	scsi_device_put(sdev);
518 
519 done:
520 	kfree(wrk);
521 }
522 
523 static void storvsc_host_scan(struct work_struct *work)
524 {
525 	struct Scsi_Host *host;
526 	struct scsi_device *sdev;
527 	struct hv_host_device *host_device =
528 		container_of(work, struct hv_host_device, host_scan_work);
529 
530 	host = host_device->host;
531 	/*
532 	 * Before scanning the host, first check to see if any of the
533 	 * currrently known devices have been hot removed. We issue a
534 	 * "unit ready" command against all currently known devices.
535 	 * This I/O will result in an error for devices that have been
536 	 * removed. As part of handling the I/O error, we remove the device.
537 	 *
538 	 * When a LUN is added or removed, the host sends us a signal to
539 	 * scan the host. Thus we are forced to discover the LUNs that
540 	 * may have been removed this way.
541 	 */
542 	mutex_lock(&host->scan_mutex);
543 	shost_for_each_device(sdev, host)
544 		scsi_test_unit_ready(sdev, 1, 1, NULL);
545 	mutex_unlock(&host->scan_mutex);
546 	/*
547 	 * Now scan the host to discover LUNs that may have been added.
548 	 */
549 	scsi_scan_host(host);
550 }
551 
552 static void storvsc_remove_lun(struct work_struct *work)
553 {
554 	struct storvsc_scan_work *wrk;
555 	struct scsi_device *sdev;
556 
557 	wrk = container_of(work, struct storvsc_scan_work, work);
558 	if (!scsi_host_get(wrk->host))
559 		goto done;
560 
561 	sdev = scsi_device_lookup(wrk->host, 0, wrk->tgt_id, wrk->lun);
562 
563 	if (sdev) {
564 		scsi_remove_device(sdev);
565 		scsi_device_put(sdev);
566 	}
567 	scsi_host_put(wrk->host);
568 
569 done:
570 	kfree(wrk);
571 }
572 
573 
574 /*
575  * We can get incoming messages from the host that are not in response to
576  * messages that we have sent out. An example of this would be messages
577  * received by the guest to notify dynamic addition/removal of LUNs. To
578  * deal with potential race conditions where the driver may be in the
579  * midst of being unloaded when we might receive an unsolicited message
580  * from the host, we have implemented a mechanism to gurantee sequential
581  * consistency:
582  *
583  * 1) Once the device is marked as being destroyed, we will fail all
584  *    outgoing messages.
585  * 2) We permit incoming messages when the device is being destroyed,
586  *    only to properly account for messages already sent out.
587  */
588 
589 static inline struct storvsc_device *get_out_stor_device(
590 					struct hv_device *device)
591 {
592 	struct storvsc_device *stor_device;
593 
594 	stor_device = hv_get_drvdata(device);
595 
596 	if (stor_device && stor_device->destroy)
597 		stor_device = NULL;
598 
599 	return stor_device;
600 }
601 
602 
603 static inline void storvsc_wait_to_drain(struct storvsc_device *dev)
604 {
605 	dev->drain_notify = true;
606 	wait_event(dev->waiting_to_drain,
607 		   atomic_read(&dev->num_outstanding_req) == 0);
608 	dev->drain_notify = false;
609 }
610 
611 static inline struct storvsc_device *get_in_stor_device(
612 					struct hv_device *device)
613 {
614 	struct storvsc_device *stor_device;
615 
616 	stor_device = hv_get_drvdata(device);
617 
618 	if (!stor_device)
619 		goto get_in_err;
620 
621 	/*
622 	 * If the device is being destroyed; allow incoming
623 	 * traffic only to cleanup outstanding requests.
624 	 */
625 
626 	if (stor_device->destroy  &&
627 		(atomic_read(&stor_device->num_outstanding_req) == 0))
628 		stor_device = NULL;
629 
630 get_in_err:
631 	return stor_device;
632 
633 }
634 
635 static void handle_sc_creation(struct vmbus_channel *new_sc)
636 {
637 	struct hv_device *device = new_sc->primary_channel->device_obj;
638 	struct device *dev = &device->device;
639 	struct storvsc_device *stor_device;
640 	struct vmstorage_channel_properties props;
641 	int ret;
642 
643 	stor_device = get_out_stor_device(device);
644 	if (!stor_device)
645 		return;
646 
647 	memset(&props, 0, sizeof(struct vmstorage_channel_properties));
648 
649 	ret = vmbus_open(new_sc,
650 			 storvsc_ringbuffer_size,
651 			 storvsc_ringbuffer_size,
652 			 (void *)&props,
653 			 sizeof(struct vmstorage_channel_properties),
654 			 storvsc_on_channel_callback, new_sc);
655 
656 	/* In case vmbus_open() fails, we don't use the sub-channel. */
657 	if (ret != 0) {
658 		dev_err(dev, "Failed to open sub-channel: err=%d\n", ret);
659 		return;
660 	}
661 
662 	/* Add the sub-channel to the array of available channels. */
663 	stor_device->stor_chns[new_sc->target_cpu] = new_sc;
664 	cpumask_set_cpu(new_sc->target_cpu, &stor_device->alloced_cpus);
665 }
666 
667 static void  handle_multichannel_storage(struct hv_device *device, int max_chns)
668 {
669 	struct device *dev = &device->device;
670 	struct storvsc_device *stor_device;
671 	int num_sc;
672 	struct storvsc_cmd_request *request;
673 	struct vstor_packet *vstor_packet;
674 	int ret, t;
675 
676 	/*
677 	 * If the number of CPUs is artificially restricted, such as
678 	 * with maxcpus=1 on the kernel boot line, Hyper-V could offer
679 	 * sub-channels >= the number of CPUs. These sub-channels
680 	 * should not be created. The primary channel is already created
681 	 * and assigned to one CPU, so check against # CPUs - 1.
682 	 */
683 	num_sc = min((int)(num_online_cpus() - 1), max_chns);
684 	if (!num_sc)
685 		return;
686 
687 	stor_device = get_out_stor_device(device);
688 	if (!stor_device)
689 		return;
690 
691 	stor_device->num_sc = num_sc;
692 	request = &stor_device->init_request;
693 	vstor_packet = &request->vstor_packet;
694 
695 	/*
696 	 * Establish a handler for dealing with subchannels.
697 	 */
698 	vmbus_set_sc_create_callback(device->channel, handle_sc_creation);
699 
700 	/*
701 	 * Request the host to create sub-channels.
702 	 */
703 	memset(request, 0, sizeof(struct storvsc_cmd_request));
704 	init_completion(&request->wait_event);
705 	vstor_packet->operation = VSTOR_OPERATION_CREATE_SUB_CHANNELS;
706 	vstor_packet->flags = REQUEST_COMPLETION_FLAG;
707 	vstor_packet->sub_channel_count = num_sc;
708 
709 	ret = vmbus_sendpacket(device->channel, vstor_packet,
710 			       (sizeof(struct vstor_packet) -
711 			       vmscsi_size_delta),
712 			       (unsigned long)request,
713 			       VM_PKT_DATA_INBAND,
714 			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
715 
716 	if (ret != 0) {
717 		dev_err(dev, "Failed to create sub-channel: err=%d\n", ret);
718 		return;
719 	}
720 
721 	t = wait_for_completion_timeout(&request->wait_event, 10*HZ);
722 	if (t == 0) {
723 		dev_err(dev, "Failed to create sub-channel: timed out\n");
724 		return;
725 	}
726 
727 	if (vstor_packet->operation != VSTOR_OPERATION_COMPLETE_IO ||
728 	    vstor_packet->status != 0) {
729 		dev_err(dev, "Failed to create sub-channel: op=%d, sts=%d\n",
730 			vstor_packet->operation, vstor_packet->status);
731 		return;
732 	}
733 
734 	/*
735 	 * We need to do nothing here, because vmbus_process_offer()
736 	 * invokes channel->sc_creation_callback, which will open and use
737 	 * the sub-channel(s).
738 	 */
739 }
740 
741 static void cache_wwn(struct storvsc_device *stor_device,
742 		      struct vstor_packet *vstor_packet)
743 {
744 	/*
745 	 * Cache the currently active port and node ww names.
746 	 */
747 	if (vstor_packet->wwn_packet.primary_active) {
748 		stor_device->node_name =
749 			wwn_to_u64(vstor_packet->wwn_packet.primary_node_wwn);
750 		stor_device->port_name =
751 			wwn_to_u64(vstor_packet->wwn_packet.primary_port_wwn);
752 	} else {
753 		stor_device->node_name =
754 			wwn_to_u64(vstor_packet->wwn_packet.secondary_node_wwn);
755 		stor_device->port_name =
756 			wwn_to_u64(vstor_packet->wwn_packet.secondary_port_wwn);
757 	}
758 }
759 
760 
761 static int storvsc_execute_vstor_op(struct hv_device *device,
762 				    struct storvsc_cmd_request *request,
763 				    bool status_check)
764 {
765 	struct vstor_packet *vstor_packet;
766 	int ret, t;
767 
768 	vstor_packet = &request->vstor_packet;
769 
770 	init_completion(&request->wait_event);
771 	vstor_packet->flags = REQUEST_COMPLETION_FLAG;
772 
773 	ret = vmbus_sendpacket(device->channel, vstor_packet,
774 			       (sizeof(struct vstor_packet) -
775 			       vmscsi_size_delta),
776 			       (unsigned long)request,
777 			       VM_PKT_DATA_INBAND,
778 			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
779 	if (ret != 0)
780 		return ret;
781 
782 	t = wait_for_completion_timeout(&request->wait_event, 5*HZ);
783 	if (t == 0)
784 		return -ETIMEDOUT;
785 
786 	if (!status_check)
787 		return ret;
788 
789 	if (vstor_packet->operation != VSTOR_OPERATION_COMPLETE_IO ||
790 	    vstor_packet->status != 0)
791 		return -EINVAL;
792 
793 	return ret;
794 }
795 
796 static int storvsc_channel_init(struct hv_device *device, bool is_fc)
797 {
798 	struct storvsc_device *stor_device;
799 	struct storvsc_cmd_request *request;
800 	struct vstor_packet *vstor_packet;
801 	int ret, i;
802 	int max_chns;
803 	bool process_sub_channels = false;
804 
805 	stor_device = get_out_stor_device(device);
806 	if (!stor_device)
807 		return -ENODEV;
808 
809 	request = &stor_device->init_request;
810 	vstor_packet = &request->vstor_packet;
811 
812 	/*
813 	 * Now, initiate the vsc/vsp initialization protocol on the open
814 	 * channel
815 	 */
816 	memset(request, 0, sizeof(struct storvsc_cmd_request));
817 	vstor_packet->operation = VSTOR_OPERATION_BEGIN_INITIALIZATION;
818 	ret = storvsc_execute_vstor_op(device, request, true);
819 	if (ret)
820 		return ret;
821 	/*
822 	 * Query host supported protocol version.
823 	 */
824 
825 	for (i = 0; i < ARRAY_SIZE(vmstor_protocols); i++) {
826 		/* reuse the packet for version range supported */
827 		memset(vstor_packet, 0, sizeof(struct vstor_packet));
828 		vstor_packet->operation =
829 			VSTOR_OPERATION_QUERY_PROTOCOL_VERSION;
830 
831 		vstor_packet->version.major_minor =
832 			vmstor_protocols[i].protocol_version;
833 
834 		/*
835 		 * The revision number is only used in Windows; set it to 0.
836 		 */
837 		vstor_packet->version.revision = 0;
838 		ret = storvsc_execute_vstor_op(device, request, false);
839 		if (ret != 0)
840 			return ret;
841 
842 		if (vstor_packet->operation != VSTOR_OPERATION_COMPLETE_IO)
843 			return -EINVAL;
844 
845 		if (vstor_packet->status == 0) {
846 			vmstor_proto_version =
847 				vmstor_protocols[i].protocol_version;
848 
849 			sense_buffer_size =
850 				vmstor_protocols[i].sense_buffer_size;
851 
852 			vmscsi_size_delta =
853 				vmstor_protocols[i].vmscsi_size_delta;
854 
855 			break;
856 		}
857 	}
858 
859 	if (vstor_packet->status != 0)
860 		return -EINVAL;
861 
862 
863 	memset(vstor_packet, 0, sizeof(struct vstor_packet));
864 	vstor_packet->operation = VSTOR_OPERATION_QUERY_PROPERTIES;
865 	ret = storvsc_execute_vstor_op(device, request, true);
866 	if (ret != 0)
867 		return ret;
868 
869 	/*
870 	 * Check to see if multi-channel support is there.
871 	 * Hosts that implement protocol version of 5.1 and above
872 	 * support multi-channel.
873 	 */
874 	max_chns = vstor_packet->storage_channel_properties.max_channel_cnt;
875 
876 	/*
877 	 * Allocate state to manage the sub-channels.
878 	 * We allocate an array based on the numbers of possible CPUs
879 	 * (Hyper-V does not support cpu online/offline).
880 	 * This Array will be sparseley populated with unique
881 	 * channels - primary + sub-channels.
882 	 * We will however populate all the slots to evenly distribute
883 	 * the load.
884 	 */
885 	stor_device->stor_chns = kcalloc(num_possible_cpus(), sizeof(void *),
886 					 GFP_KERNEL);
887 	if (stor_device->stor_chns == NULL)
888 		return -ENOMEM;
889 
890 	stor_device->stor_chns[device->channel->target_cpu] = device->channel;
891 	cpumask_set_cpu(device->channel->target_cpu,
892 			&stor_device->alloced_cpus);
893 
894 	if (vmstor_proto_version >= VMSTOR_PROTO_VERSION_WIN8) {
895 		if (vstor_packet->storage_channel_properties.flags &
896 		    STORAGE_CHANNEL_SUPPORTS_MULTI_CHANNEL)
897 			process_sub_channels = true;
898 	}
899 	stor_device->max_transfer_bytes =
900 		vstor_packet->storage_channel_properties.max_transfer_bytes;
901 
902 	if (!is_fc)
903 		goto done;
904 
905 	/*
906 	 * For FC devices retrieve FC HBA data.
907 	 */
908 	memset(vstor_packet, 0, sizeof(struct vstor_packet));
909 	vstor_packet->operation = VSTOR_OPERATION_FCHBA_DATA;
910 	ret = storvsc_execute_vstor_op(device, request, true);
911 	if (ret != 0)
912 		return ret;
913 
914 	/*
915 	 * Cache the currently active port and node ww names.
916 	 */
917 	cache_wwn(stor_device, vstor_packet);
918 
919 done:
920 
921 	memset(vstor_packet, 0, sizeof(struct vstor_packet));
922 	vstor_packet->operation = VSTOR_OPERATION_END_INITIALIZATION;
923 	ret = storvsc_execute_vstor_op(device, request, true);
924 	if (ret != 0)
925 		return ret;
926 
927 	if (process_sub_channels)
928 		handle_multichannel_storage(device, max_chns);
929 
930 	return ret;
931 }
932 
933 static void storvsc_handle_error(struct vmscsi_request *vm_srb,
934 				struct scsi_cmnd *scmnd,
935 				struct Scsi_Host *host,
936 				u8 asc, u8 ascq)
937 {
938 	struct storvsc_scan_work *wrk;
939 	void (*process_err_fn)(struct work_struct *work);
940 	struct hv_host_device *host_dev = shost_priv(host);
941 	bool do_work = false;
942 
943 	switch (SRB_STATUS(vm_srb->srb_status)) {
944 	case SRB_STATUS_ERROR:
945 		/*
946 		 * Let upper layer deal with error when
947 		 * sense message is present.
948 		 */
949 
950 		if (vm_srb->srb_status & SRB_STATUS_AUTOSENSE_VALID)
951 			break;
952 		/*
953 		 * If there is an error; offline the device since all
954 		 * error recovery strategies would have already been
955 		 * deployed on the host side. However, if the command
956 		 * were a pass-through command deal with it appropriately.
957 		 */
958 		switch (scmnd->cmnd[0]) {
959 		case ATA_16:
960 		case ATA_12:
961 			set_host_byte(scmnd, DID_PASSTHROUGH);
962 			break;
963 		/*
964 		 * On Some Windows hosts TEST_UNIT_READY command can return
965 		 * SRB_STATUS_ERROR, let the upper level code deal with it
966 		 * based on the sense information.
967 		 */
968 		case TEST_UNIT_READY:
969 			break;
970 		default:
971 			set_host_byte(scmnd, DID_ERROR);
972 		}
973 		break;
974 	case SRB_STATUS_INVALID_LUN:
975 		set_host_byte(scmnd, DID_NO_CONNECT);
976 		do_work = true;
977 		process_err_fn = storvsc_remove_lun;
978 		break;
979 	case SRB_STATUS_ABORTED:
980 		if (vm_srb->srb_status & SRB_STATUS_AUTOSENSE_VALID &&
981 		    (asc == 0x2a) && (ascq == 0x9)) {
982 			do_work = true;
983 			process_err_fn = storvsc_device_scan;
984 			/*
985 			 * Retry the I/O that trigerred this.
986 			 */
987 			set_host_byte(scmnd, DID_REQUEUE);
988 		}
989 		break;
990 	}
991 
992 	if (!do_work)
993 		return;
994 
995 	/*
996 	 * We need to schedule work to process this error; schedule it.
997 	 */
998 	wrk = kmalloc(sizeof(struct storvsc_scan_work), GFP_ATOMIC);
999 	if (!wrk) {
1000 		set_host_byte(scmnd, DID_TARGET_FAILURE);
1001 		return;
1002 	}
1003 
1004 	wrk->host = host;
1005 	wrk->lun = vm_srb->lun;
1006 	wrk->tgt_id = vm_srb->target_id;
1007 	INIT_WORK(&wrk->work, process_err_fn);
1008 	queue_work(host_dev->handle_error_wq, &wrk->work);
1009 }
1010 
1011 
1012 static void storvsc_command_completion(struct storvsc_cmd_request *cmd_request,
1013 				       struct storvsc_device *stor_dev)
1014 {
1015 	struct scsi_cmnd *scmnd = cmd_request->cmd;
1016 	struct scsi_sense_hdr sense_hdr;
1017 	struct vmscsi_request *vm_srb;
1018 	u32 data_transfer_length;
1019 	struct Scsi_Host *host;
1020 	u32 payload_sz = cmd_request->payload_sz;
1021 	void *payload = cmd_request->payload;
1022 
1023 	host = stor_dev->host;
1024 
1025 	vm_srb = &cmd_request->vstor_packet.vm_srb;
1026 	data_transfer_length = vm_srb->data_transfer_length;
1027 
1028 	scmnd->result = vm_srb->scsi_status;
1029 
1030 	if (scmnd->result) {
1031 		if (scsi_normalize_sense(scmnd->sense_buffer,
1032 				SCSI_SENSE_BUFFERSIZE, &sense_hdr) &&
1033 		    !(sense_hdr.sense_key == NOT_READY &&
1034 				 sense_hdr.asc == 0x03A) &&
1035 		    do_logging(STORVSC_LOGGING_ERROR))
1036 			scsi_print_sense_hdr(scmnd->device, "storvsc",
1037 					     &sense_hdr);
1038 	}
1039 
1040 	if (vm_srb->srb_status != SRB_STATUS_SUCCESS) {
1041 		storvsc_handle_error(vm_srb, scmnd, host, sense_hdr.asc,
1042 					 sense_hdr.ascq);
1043 		/*
1044 		 * The Windows driver set data_transfer_length on
1045 		 * SRB_STATUS_DATA_OVERRUN. On other errors, this value
1046 		 * is untouched.  In these cases we set it to 0.
1047 		 */
1048 		if (vm_srb->srb_status != SRB_STATUS_DATA_OVERRUN)
1049 			data_transfer_length = 0;
1050 	}
1051 
1052 	scsi_set_resid(scmnd,
1053 		cmd_request->payload->range.len - data_transfer_length);
1054 
1055 	scmnd->scsi_done(scmnd);
1056 
1057 	if (payload_sz >
1058 		sizeof(struct vmbus_channel_packet_multipage_buffer))
1059 		kfree(payload);
1060 }
1061 
1062 static void storvsc_on_io_completion(struct storvsc_device *stor_device,
1063 				  struct vstor_packet *vstor_packet,
1064 				  struct storvsc_cmd_request *request)
1065 {
1066 	struct vstor_packet *stor_pkt;
1067 	struct hv_device *device = stor_device->device;
1068 
1069 	stor_pkt = &request->vstor_packet;
1070 
1071 	/*
1072 	 * The current SCSI handling on the host side does
1073 	 * not correctly handle:
1074 	 * INQUIRY command with page code parameter set to 0x80
1075 	 * MODE_SENSE command with cmd[2] == 0x1c
1076 	 *
1077 	 * Setup srb and scsi status so this won't be fatal.
1078 	 * We do this so we can distinguish truly fatal failues
1079 	 * (srb status == 0x4) and off-line the device in that case.
1080 	 */
1081 
1082 	if ((stor_pkt->vm_srb.cdb[0] == INQUIRY) ||
1083 	   (stor_pkt->vm_srb.cdb[0] == MODE_SENSE)) {
1084 		vstor_packet->vm_srb.scsi_status = 0;
1085 		vstor_packet->vm_srb.srb_status = SRB_STATUS_SUCCESS;
1086 	}
1087 
1088 
1089 	/* Copy over the status...etc */
1090 	stor_pkt->vm_srb.scsi_status = vstor_packet->vm_srb.scsi_status;
1091 	stor_pkt->vm_srb.srb_status = vstor_packet->vm_srb.srb_status;
1092 	stor_pkt->vm_srb.sense_info_length =
1093 	vstor_packet->vm_srb.sense_info_length;
1094 
1095 	if (vstor_packet->vm_srb.scsi_status != 0 ||
1096 	    vstor_packet->vm_srb.srb_status != SRB_STATUS_SUCCESS)
1097 		storvsc_log(device, STORVSC_LOGGING_WARN,
1098 			"cmd 0x%x scsi status 0x%x srb status 0x%x\n",
1099 			stor_pkt->vm_srb.cdb[0],
1100 			vstor_packet->vm_srb.scsi_status,
1101 			vstor_packet->vm_srb.srb_status);
1102 
1103 	if ((vstor_packet->vm_srb.scsi_status & 0xFF) == 0x02) {
1104 		/* CHECK_CONDITION */
1105 		if (vstor_packet->vm_srb.srb_status &
1106 			SRB_STATUS_AUTOSENSE_VALID) {
1107 			/* autosense data available */
1108 
1109 			storvsc_log(device, STORVSC_LOGGING_WARN,
1110 				"stor pkt %p autosense data valid - len %d\n",
1111 				request, vstor_packet->vm_srb.sense_info_length);
1112 
1113 			memcpy(request->cmd->sense_buffer,
1114 			       vstor_packet->vm_srb.sense_data,
1115 			       vstor_packet->vm_srb.sense_info_length);
1116 
1117 		}
1118 	}
1119 
1120 	stor_pkt->vm_srb.data_transfer_length =
1121 	vstor_packet->vm_srb.data_transfer_length;
1122 
1123 	storvsc_command_completion(request, stor_device);
1124 
1125 	if (atomic_dec_and_test(&stor_device->num_outstanding_req) &&
1126 		stor_device->drain_notify)
1127 		wake_up(&stor_device->waiting_to_drain);
1128 
1129 
1130 }
1131 
1132 static void storvsc_on_receive(struct storvsc_device *stor_device,
1133 			     struct vstor_packet *vstor_packet,
1134 			     struct storvsc_cmd_request *request)
1135 {
1136 	struct hv_host_device *host_dev;
1137 	switch (vstor_packet->operation) {
1138 	case VSTOR_OPERATION_COMPLETE_IO:
1139 		storvsc_on_io_completion(stor_device, vstor_packet, request);
1140 		break;
1141 
1142 	case VSTOR_OPERATION_REMOVE_DEVICE:
1143 	case VSTOR_OPERATION_ENUMERATE_BUS:
1144 		host_dev = shost_priv(stor_device->host);
1145 		queue_work(
1146 			host_dev->handle_error_wq, &host_dev->host_scan_work);
1147 		break;
1148 
1149 	case VSTOR_OPERATION_FCHBA_DATA:
1150 		cache_wwn(stor_device, vstor_packet);
1151 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
1152 		fc_host_node_name(stor_device->host) = stor_device->node_name;
1153 		fc_host_port_name(stor_device->host) = stor_device->port_name;
1154 #endif
1155 		break;
1156 	default:
1157 		break;
1158 	}
1159 }
1160 
1161 static void storvsc_on_channel_callback(void *context)
1162 {
1163 	struct vmbus_channel *channel = (struct vmbus_channel *)context;
1164 	const struct vmpacket_descriptor *desc;
1165 	struct hv_device *device;
1166 	struct storvsc_device *stor_device;
1167 
1168 	if (channel->primary_channel != NULL)
1169 		device = channel->primary_channel->device_obj;
1170 	else
1171 		device = channel->device_obj;
1172 
1173 	stor_device = get_in_stor_device(device);
1174 	if (!stor_device)
1175 		return;
1176 
1177 	foreach_vmbus_pkt(desc, channel) {
1178 		void *packet = hv_pkt_data(desc);
1179 		struct storvsc_cmd_request *request;
1180 
1181 		request = (struct storvsc_cmd_request *)
1182 			((unsigned long)desc->trans_id);
1183 
1184 		if (request == &stor_device->init_request ||
1185 		    request == &stor_device->reset_request) {
1186 			memcpy(&request->vstor_packet, packet,
1187 			       (sizeof(struct vstor_packet) - vmscsi_size_delta));
1188 			complete(&request->wait_event);
1189 		} else {
1190 			storvsc_on_receive(stor_device, packet, request);
1191 		}
1192 	}
1193 }
1194 
1195 static int storvsc_connect_to_vsp(struct hv_device *device, u32 ring_size,
1196 				  bool is_fc)
1197 {
1198 	struct vmstorage_channel_properties props;
1199 	int ret;
1200 
1201 	memset(&props, 0, sizeof(struct vmstorage_channel_properties));
1202 
1203 	ret = vmbus_open(device->channel,
1204 			 ring_size,
1205 			 ring_size,
1206 			 (void *)&props,
1207 			 sizeof(struct vmstorage_channel_properties),
1208 			 storvsc_on_channel_callback, device->channel);
1209 
1210 	if (ret != 0)
1211 		return ret;
1212 
1213 	ret = storvsc_channel_init(device, is_fc);
1214 
1215 	return ret;
1216 }
1217 
1218 static int storvsc_dev_remove(struct hv_device *device)
1219 {
1220 	struct storvsc_device *stor_device;
1221 
1222 	stor_device = hv_get_drvdata(device);
1223 
1224 	stor_device->destroy = true;
1225 
1226 	/* Make sure flag is set before waiting */
1227 	wmb();
1228 
1229 	/*
1230 	 * At this point, all outbound traffic should be disable. We
1231 	 * only allow inbound traffic (responses) to proceed so that
1232 	 * outstanding requests can be completed.
1233 	 */
1234 
1235 	storvsc_wait_to_drain(stor_device);
1236 
1237 	/*
1238 	 * Since we have already drained, we don't need to busy wait
1239 	 * as was done in final_release_stor_device()
1240 	 * Note that we cannot set the ext pointer to NULL until
1241 	 * we have drained - to drain the outgoing packets, we need to
1242 	 * allow incoming packets.
1243 	 */
1244 	hv_set_drvdata(device, NULL);
1245 
1246 	/* Close the channel */
1247 	vmbus_close(device->channel);
1248 
1249 	kfree(stor_device->stor_chns);
1250 	kfree(stor_device);
1251 	return 0;
1252 }
1253 
1254 static struct vmbus_channel *get_og_chn(struct storvsc_device *stor_device,
1255 					u16 q_num)
1256 {
1257 	u16 slot = 0;
1258 	u16 hash_qnum;
1259 	const struct cpumask *node_mask;
1260 	int num_channels, tgt_cpu;
1261 
1262 	if (stor_device->num_sc == 0)
1263 		return stor_device->device->channel;
1264 
1265 	/*
1266 	 * Our channel array is sparsley populated and we
1267 	 * initiated I/O on a processor/hw-q that does not
1268 	 * currently have a designated channel. Fix this.
1269 	 * The strategy is simple:
1270 	 * I. Ensure NUMA locality
1271 	 * II. Distribute evenly (best effort)
1272 	 * III. Mapping is persistent.
1273 	 */
1274 
1275 	node_mask = cpumask_of_node(cpu_to_node(q_num));
1276 
1277 	num_channels = 0;
1278 	for_each_cpu(tgt_cpu, &stor_device->alloced_cpus) {
1279 		if (cpumask_test_cpu(tgt_cpu, node_mask))
1280 			num_channels++;
1281 	}
1282 	if (num_channels == 0)
1283 		return stor_device->device->channel;
1284 
1285 	hash_qnum = q_num;
1286 	while (hash_qnum >= num_channels)
1287 		hash_qnum -= num_channels;
1288 
1289 	for_each_cpu(tgt_cpu, &stor_device->alloced_cpus) {
1290 		if (!cpumask_test_cpu(tgt_cpu, node_mask))
1291 			continue;
1292 		if (slot == hash_qnum)
1293 			break;
1294 		slot++;
1295 	}
1296 
1297 	stor_device->stor_chns[q_num] = stor_device->stor_chns[tgt_cpu];
1298 
1299 	return stor_device->stor_chns[q_num];
1300 }
1301 
1302 
1303 static int storvsc_do_io(struct hv_device *device,
1304 			 struct storvsc_cmd_request *request, u16 q_num)
1305 {
1306 	struct storvsc_device *stor_device;
1307 	struct vstor_packet *vstor_packet;
1308 	struct vmbus_channel *outgoing_channel, *channel;
1309 	int ret = 0;
1310 	const struct cpumask *node_mask;
1311 	int tgt_cpu;
1312 
1313 	vstor_packet = &request->vstor_packet;
1314 	stor_device = get_out_stor_device(device);
1315 
1316 	if (!stor_device)
1317 		return -ENODEV;
1318 
1319 
1320 	request->device  = device;
1321 	/*
1322 	 * Select an an appropriate channel to send the request out.
1323 	 */
1324 	if (stor_device->stor_chns[q_num] != NULL) {
1325 		outgoing_channel = stor_device->stor_chns[q_num];
1326 		if (outgoing_channel->target_cpu == q_num) {
1327 			/*
1328 			 * Ideally, we want to pick a different channel if
1329 			 * available on the same NUMA node.
1330 			 */
1331 			node_mask = cpumask_of_node(cpu_to_node(q_num));
1332 			for_each_cpu_wrap(tgt_cpu,
1333 				 &stor_device->alloced_cpus, q_num + 1) {
1334 				if (!cpumask_test_cpu(tgt_cpu, node_mask))
1335 					continue;
1336 				if (tgt_cpu == q_num)
1337 					continue;
1338 				channel = stor_device->stor_chns[tgt_cpu];
1339 				if (hv_get_avail_to_write_percent(
1340 							&channel->outbound)
1341 						> ring_avail_percent_lowater) {
1342 					outgoing_channel = channel;
1343 					goto found_channel;
1344 				}
1345 			}
1346 
1347 			/*
1348 			 * All the other channels on the same NUMA node are
1349 			 * busy. Try to use the channel on the current CPU
1350 			 */
1351 			if (hv_get_avail_to_write_percent(
1352 						&outgoing_channel->outbound)
1353 					> ring_avail_percent_lowater)
1354 				goto found_channel;
1355 
1356 			/*
1357 			 * If we reach here, all the channels on the current
1358 			 * NUMA node are busy. Try to find a channel in
1359 			 * other NUMA nodes
1360 			 */
1361 			for_each_cpu(tgt_cpu, &stor_device->alloced_cpus) {
1362 				if (cpumask_test_cpu(tgt_cpu, node_mask))
1363 					continue;
1364 				channel = stor_device->stor_chns[tgt_cpu];
1365 				if (hv_get_avail_to_write_percent(
1366 							&channel->outbound)
1367 						> ring_avail_percent_lowater) {
1368 					outgoing_channel = channel;
1369 					goto found_channel;
1370 				}
1371 			}
1372 		}
1373 	} else {
1374 		outgoing_channel = get_og_chn(stor_device, q_num);
1375 	}
1376 
1377 found_channel:
1378 	vstor_packet->flags |= REQUEST_COMPLETION_FLAG;
1379 
1380 	vstor_packet->vm_srb.length = (sizeof(struct vmscsi_request) -
1381 					vmscsi_size_delta);
1382 
1383 
1384 	vstor_packet->vm_srb.sense_info_length = sense_buffer_size;
1385 
1386 
1387 	vstor_packet->vm_srb.data_transfer_length =
1388 	request->payload->range.len;
1389 
1390 	vstor_packet->operation = VSTOR_OPERATION_EXECUTE_SRB;
1391 
1392 	if (request->payload->range.len) {
1393 
1394 		ret = vmbus_sendpacket_mpb_desc(outgoing_channel,
1395 				request->payload, request->payload_sz,
1396 				vstor_packet,
1397 				(sizeof(struct vstor_packet) -
1398 				vmscsi_size_delta),
1399 				(unsigned long)request);
1400 	} else {
1401 		ret = vmbus_sendpacket(outgoing_channel, vstor_packet,
1402 			       (sizeof(struct vstor_packet) -
1403 				vmscsi_size_delta),
1404 			       (unsigned long)request,
1405 			       VM_PKT_DATA_INBAND,
1406 			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
1407 	}
1408 
1409 	if (ret != 0)
1410 		return ret;
1411 
1412 	atomic_inc(&stor_device->num_outstanding_req);
1413 
1414 	return ret;
1415 }
1416 
1417 static int storvsc_device_alloc(struct scsi_device *sdevice)
1418 {
1419 	/*
1420 	 * Set blist flag to permit the reading of the VPD pages even when
1421 	 * the target may claim SPC-2 compliance. MSFT targets currently
1422 	 * claim SPC-2 compliance while they implement post SPC-2 features.
1423 	 * With this flag we can correctly handle WRITE_SAME_16 issues.
1424 	 *
1425 	 * Hypervisor reports SCSI_UNKNOWN type for DVD ROM device but
1426 	 * still supports REPORT LUN.
1427 	 */
1428 	sdevice->sdev_bflags = BLIST_REPORTLUN2 | BLIST_TRY_VPD_PAGES;
1429 
1430 	return 0;
1431 }
1432 
1433 static int storvsc_device_configure(struct scsi_device *sdevice)
1434 {
1435 	blk_queue_rq_timeout(sdevice->request_queue, (storvsc_timeout * HZ));
1436 
1437 	/* Ensure there are no gaps in presented sgls */
1438 	blk_queue_virt_boundary(sdevice->request_queue, PAGE_SIZE - 1);
1439 
1440 	sdevice->no_write_same = 1;
1441 
1442 	/*
1443 	 * If the host is WIN8 or WIN8 R2, claim conformance to SPC-3
1444 	 * if the device is a MSFT virtual device.  If the host is
1445 	 * WIN10 or newer, allow write_same.
1446 	 */
1447 	if (!strncmp(sdevice->vendor, "Msft", 4)) {
1448 		switch (vmstor_proto_version) {
1449 		case VMSTOR_PROTO_VERSION_WIN8:
1450 		case VMSTOR_PROTO_VERSION_WIN8_1:
1451 			sdevice->scsi_level = SCSI_SPC_3;
1452 			break;
1453 		}
1454 
1455 		if (vmstor_proto_version >= VMSTOR_PROTO_VERSION_WIN10)
1456 			sdevice->no_write_same = 0;
1457 	}
1458 
1459 	return 0;
1460 }
1461 
1462 static int storvsc_get_chs(struct scsi_device *sdev, struct block_device * bdev,
1463 			   sector_t capacity, int *info)
1464 {
1465 	sector_t nsect = capacity;
1466 	sector_t cylinders = nsect;
1467 	int heads, sectors_pt;
1468 
1469 	/*
1470 	 * We are making up these values; let us keep it simple.
1471 	 */
1472 	heads = 0xff;
1473 	sectors_pt = 0x3f;      /* Sectors per track */
1474 	sector_div(cylinders, heads * sectors_pt);
1475 	if ((sector_t)(cylinders + 1) * heads * sectors_pt < nsect)
1476 		cylinders = 0xffff;
1477 
1478 	info[0] = heads;
1479 	info[1] = sectors_pt;
1480 	info[2] = (int)cylinders;
1481 
1482 	return 0;
1483 }
1484 
1485 static int storvsc_host_reset_handler(struct scsi_cmnd *scmnd)
1486 {
1487 	struct hv_host_device *host_dev = shost_priv(scmnd->device->host);
1488 	struct hv_device *device = host_dev->dev;
1489 
1490 	struct storvsc_device *stor_device;
1491 	struct storvsc_cmd_request *request;
1492 	struct vstor_packet *vstor_packet;
1493 	int ret, t;
1494 
1495 
1496 	stor_device = get_out_stor_device(device);
1497 	if (!stor_device)
1498 		return FAILED;
1499 
1500 	request = &stor_device->reset_request;
1501 	vstor_packet = &request->vstor_packet;
1502 
1503 	init_completion(&request->wait_event);
1504 
1505 	vstor_packet->operation = VSTOR_OPERATION_RESET_BUS;
1506 	vstor_packet->flags = REQUEST_COMPLETION_FLAG;
1507 	vstor_packet->vm_srb.path_id = stor_device->path_id;
1508 
1509 	ret = vmbus_sendpacket(device->channel, vstor_packet,
1510 			       (sizeof(struct vstor_packet) -
1511 				vmscsi_size_delta),
1512 			       (unsigned long)&stor_device->reset_request,
1513 			       VM_PKT_DATA_INBAND,
1514 			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
1515 	if (ret != 0)
1516 		return FAILED;
1517 
1518 	t = wait_for_completion_timeout(&request->wait_event, 5*HZ);
1519 	if (t == 0)
1520 		return TIMEOUT_ERROR;
1521 
1522 
1523 	/*
1524 	 * At this point, all outstanding requests in the adapter
1525 	 * should have been flushed out and return to us
1526 	 * There is a potential race here where the host may be in
1527 	 * the process of responding when we return from here.
1528 	 * Just wait for all in-transit packets to be accounted for
1529 	 * before we return from here.
1530 	 */
1531 	storvsc_wait_to_drain(stor_device);
1532 
1533 	return SUCCESS;
1534 }
1535 
1536 /*
1537  * The host guarantees to respond to each command, although I/O latencies might
1538  * be unbounded on Azure.  Reset the timer unconditionally to give the host a
1539  * chance to perform EH.
1540  */
1541 static enum blk_eh_timer_return storvsc_eh_timed_out(struct scsi_cmnd *scmnd)
1542 {
1543 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
1544 	if (scmnd->device->host->transportt == fc_transport_template)
1545 		return fc_eh_timed_out(scmnd);
1546 #endif
1547 	return BLK_EH_RESET_TIMER;
1548 }
1549 
1550 static bool storvsc_scsi_cmd_ok(struct scsi_cmnd *scmnd)
1551 {
1552 	bool allowed = true;
1553 	u8 scsi_op = scmnd->cmnd[0];
1554 
1555 	switch (scsi_op) {
1556 	/* the host does not handle WRITE_SAME, log accident usage */
1557 	case WRITE_SAME:
1558 	/*
1559 	 * smartd sends this command and the host does not handle
1560 	 * this. So, don't send it.
1561 	 */
1562 	case SET_WINDOW:
1563 		scmnd->result = ILLEGAL_REQUEST << 16;
1564 		allowed = false;
1565 		break;
1566 	default:
1567 		break;
1568 	}
1569 	return allowed;
1570 }
1571 
1572 static int storvsc_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *scmnd)
1573 {
1574 	int ret;
1575 	struct hv_host_device *host_dev = shost_priv(host);
1576 	struct hv_device *dev = host_dev->dev;
1577 	struct storvsc_cmd_request *cmd_request = scsi_cmd_priv(scmnd);
1578 	int i;
1579 	struct scatterlist *sgl;
1580 	unsigned int sg_count = 0;
1581 	struct vmscsi_request *vm_srb;
1582 	struct scatterlist *cur_sgl;
1583 	struct vmbus_packet_mpb_array  *payload;
1584 	u32 payload_sz;
1585 	u32 length;
1586 
1587 	if (vmstor_proto_version <= VMSTOR_PROTO_VERSION_WIN8) {
1588 		/*
1589 		 * On legacy hosts filter unimplemented commands.
1590 		 * Future hosts are expected to correctly handle
1591 		 * unsupported commands. Furthermore, it is
1592 		 * possible that some of the currently
1593 		 * unsupported commands maybe supported in
1594 		 * future versions of the host.
1595 		 */
1596 		if (!storvsc_scsi_cmd_ok(scmnd)) {
1597 			scmnd->scsi_done(scmnd);
1598 			return 0;
1599 		}
1600 	}
1601 
1602 	/* Setup the cmd request */
1603 	cmd_request->cmd = scmnd;
1604 
1605 	vm_srb = &cmd_request->vstor_packet.vm_srb;
1606 	vm_srb->win8_extension.time_out_value = 60;
1607 
1608 	vm_srb->win8_extension.srb_flags |=
1609 		SRB_FLAGS_DISABLE_SYNCH_TRANSFER;
1610 
1611 	if (scmnd->device->tagged_supported) {
1612 		vm_srb->win8_extension.srb_flags |=
1613 		(SRB_FLAGS_QUEUE_ACTION_ENABLE | SRB_FLAGS_NO_QUEUE_FREEZE);
1614 		vm_srb->win8_extension.queue_tag = SP_UNTAGGED;
1615 		vm_srb->win8_extension.queue_action = SRB_SIMPLE_TAG_REQUEST;
1616 	}
1617 
1618 	/* Build the SRB */
1619 	switch (scmnd->sc_data_direction) {
1620 	case DMA_TO_DEVICE:
1621 		vm_srb->data_in = WRITE_TYPE;
1622 		vm_srb->win8_extension.srb_flags |= SRB_FLAGS_DATA_OUT;
1623 		break;
1624 	case DMA_FROM_DEVICE:
1625 		vm_srb->data_in = READ_TYPE;
1626 		vm_srb->win8_extension.srb_flags |= SRB_FLAGS_DATA_IN;
1627 		break;
1628 	case DMA_NONE:
1629 		vm_srb->data_in = UNKNOWN_TYPE;
1630 		vm_srb->win8_extension.srb_flags |= SRB_FLAGS_NO_DATA_TRANSFER;
1631 		break;
1632 	default:
1633 		/*
1634 		 * This is DMA_BIDIRECTIONAL or something else we are never
1635 		 * supposed to see here.
1636 		 */
1637 		WARN(1, "Unexpected data direction: %d\n",
1638 		     scmnd->sc_data_direction);
1639 		return -EINVAL;
1640 	}
1641 
1642 
1643 	vm_srb->port_number = host_dev->port;
1644 	vm_srb->path_id = scmnd->device->channel;
1645 	vm_srb->target_id = scmnd->device->id;
1646 	vm_srb->lun = scmnd->device->lun;
1647 
1648 	vm_srb->cdb_length = scmnd->cmd_len;
1649 
1650 	memcpy(vm_srb->cdb, scmnd->cmnd, vm_srb->cdb_length);
1651 
1652 	sgl = (struct scatterlist *)scsi_sglist(scmnd);
1653 	sg_count = scsi_sg_count(scmnd);
1654 
1655 	length = scsi_bufflen(scmnd);
1656 	payload = (struct vmbus_packet_mpb_array *)&cmd_request->mpb;
1657 	payload_sz = sizeof(cmd_request->mpb);
1658 
1659 	if (sg_count) {
1660 		if (sg_count > MAX_PAGE_BUFFER_COUNT) {
1661 
1662 			payload_sz = (sg_count * sizeof(u64) +
1663 				      sizeof(struct vmbus_packet_mpb_array));
1664 			payload = kzalloc(payload_sz, GFP_ATOMIC);
1665 			if (!payload)
1666 				return SCSI_MLQUEUE_DEVICE_BUSY;
1667 		}
1668 
1669 		payload->range.len = length;
1670 		payload->range.offset = sgl[0].offset;
1671 
1672 		cur_sgl = sgl;
1673 		for (i = 0; i < sg_count; i++) {
1674 			payload->range.pfn_array[i] =
1675 				page_to_pfn(sg_page((cur_sgl)));
1676 			cur_sgl = sg_next(cur_sgl);
1677 		}
1678 	}
1679 
1680 	cmd_request->payload = payload;
1681 	cmd_request->payload_sz = payload_sz;
1682 
1683 	/* Invokes the vsc to start an IO */
1684 	ret = storvsc_do_io(dev, cmd_request, get_cpu());
1685 	put_cpu();
1686 
1687 	if (ret == -EAGAIN) {
1688 		if (payload_sz > sizeof(cmd_request->mpb))
1689 			kfree(payload);
1690 		/* no more space */
1691 		return SCSI_MLQUEUE_DEVICE_BUSY;
1692 	}
1693 
1694 	return 0;
1695 }
1696 
1697 static struct scsi_host_template scsi_driver = {
1698 	.module	=		THIS_MODULE,
1699 	.name =			"storvsc_host_t",
1700 	.cmd_size =             sizeof(struct storvsc_cmd_request),
1701 	.bios_param =		storvsc_get_chs,
1702 	.queuecommand =		storvsc_queuecommand,
1703 	.eh_host_reset_handler =	storvsc_host_reset_handler,
1704 	.proc_name =		"storvsc_host",
1705 	.eh_timed_out =		storvsc_eh_timed_out,
1706 	.slave_alloc =		storvsc_device_alloc,
1707 	.slave_configure =	storvsc_device_configure,
1708 	.cmd_per_lun =		2048,
1709 	.this_id =		-1,
1710 	/* Make sure we dont get a sg segment crosses a page boundary */
1711 	.dma_boundary =		PAGE_SIZE-1,
1712 	.no_write_same =	1,
1713 	.track_queue_depth =	1,
1714 };
1715 
1716 enum {
1717 	SCSI_GUID,
1718 	IDE_GUID,
1719 	SFC_GUID,
1720 };
1721 
1722 static const struct hv_vmbus_device_id id_table[] = {
1723 	/* SCSI guid */
1724 	{ HV_SCSI_GUID,
1725 	  .driver_data = SCSI_GUID
1726 	},
1727 	/* IDE guid */
1728 	{ HV_IDE_GUID,
1729 	  .driver_data = IDE_GUID
1730 	},
1731 	/* Fibre Channel GUID */
1732 	{
1733 	  HV_SYNTHFC_GUID,
1734 	  .driver_data = SFC_GUID
1735 	},
1736 	{ },
1737 };
1738 
1739 MODULE_DEVICE_TABLE(vmbus, id_table);
1740 
1741 static int storvsc_probe(struct hv_device *device,
1742 			const struct hv_vmbus_device_id *dev_id)
1743 {
1744 	int ret;
1745 	int num_cpus = num_online_cpus();
1746 	struct Scsi_Host *host;
1747 	struct hv_host_device *host_dev;
1748 	bool dev_is_ide = ((dev_id->driver_data == IDE_GUID) ? true : false);
1749 	bool is_fc = ((dev_id->driver_data == SFC_GUID) ? true : false);
1750 	int target = 0;
1751 	struct storvsc_device *stor_device;
1752 	int max_luns_per_target;
1753 	int max_targets;
1754 	int max_channels;
1755 	int max_sub_channels = 0;
1756 
1757 	/*
1758 	 * Based on the windows host we are running on,
1759 	 * set state to properly communicate with the host.
1760 	 */
1761 
1762 	if (vmbus_proto_version < VERSION_WIN8) {
1763 		max_luns_per_target = STORVSC_IDE_MAX_LUNS_PER_TARGET;
1764 		max_targets = STORVSC_IDE_MAX_TARGETS;
1765 		max_channels = STORVSC_IDE_MAX_CHANNELS;
1766 	} else {
1767 		max_luns_per_target = STORVSC_MAX_LUNS_PER_TARGET;
1768 		max_targets = STORVSC_MAX_TARGETS;
1769 		max_channels = STORVSC_MAX_CHANNELS;
1770 		/*
1771 		 * On Windows8 and above, we support sub-channels for storage
1772 		 * on SCSI and FC controllers.
1773 		 * The number of sub-channels offerred is based on the number of
1774 		 * VCPUs in the guest.
1775 		 */
1776 		if (!dev_is_ide)
1777 			max_sub_channels =
1778 				(num_cpus - 1) / storvsc_vcpus_per_sub_channel;
1779 	}
1780 
1781 	scsi_driver.can_queue = max_outstanding_req_per_channel *
1782 				(max_sub_channels + 1) *
1783 				(100 - ring_avail_percent_lowater) / 100;
1784 
1785 	host = scsi_host_alloc(&scsi_driver,
1786 			       sizeof(struct hv_host_device));
1787 	if (!host)
1788 		return -ENOMEM;
1789 
1790 	host_dev = shost_priv(host);
1791 	memset(host_dev, 0, sizeof(struct hv_host_device));
1792 
1793 	host_dev->port = host->host_no;
1794 	host_dev->dev = device;
1795 	host_dev->host = host;
1796 
1797 
1798 	stor_device = kzalloc(sizeof(struct storvsc_device), GFP_KERNEL);
1799 	if (!stor_device) {
1800 		ret = -ENOMEM;
1801 		goto err_out0;
1802 	}
1803 
1804 	stor_device->destroy = false;
1805 	init_waitqueue_head(&stor_device->waiting_to_drain);
1806 	stor_device->device = device;
1807 	stor_device->host = host;
1808 	hv_set_drvdata(device, stor_device);
1809 
1810 	stor_device->port_number = host->host_no;
1811 	ret = storvsc_connect_to_vsp(device, storvsc_ringbuffer_size, is_fc);
1812 	if (ret)
1813 		goto err_out1;
1814 
1815 	host_dev->path = stor_device->path_id;
1816 	host_dev->target = stor_device->target_id;
1817 
1818 	switch (dev_id->driver_data) {
1819 	case SFC_GUID:
1820 		host->max_lun = STORVSC_FC_MAX_LUNS_PER_TARGET;
1821 		host->max_id = STORVSC_FC_MAX_TARGETS;
1822 		host->max_channel = STORVSC_FC_MAX_CHANNELS - 1;
1823 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
1824 		host->transportt = fc_transport_template;
1825 #endif
1826 		break;
1827 
1828 	case SCSI_GUID:
1829 		host->max_lun = max_luns_per_target;
1830 		host->max_id = max_targets;
1831 		host->max_channel = max_channels - 1;
1832 		break;
1833 
1834 	default:
1835 		host->max_lun = STORVSC_IDE_MAX_LUNS_PER_TARGET;
1836 		host->max_id = STORVSC_IDE_MAX_TARGETS;
1837 		host->max_channel = STORVSC_IDE_MAX_CHANNELS - 1;
1838 		break;
1839 	}
1840 	/* max cmd length */
1841 	host->max_cmd_len = STORVSC_MAX_CMD_LEN;
1842 
1843 	/*
1844 	 * set the table size based on the info we got
1845 	 * from the host.
1846 	 */
1847 	host->sg_tablesize = (stor_device->max_transfer_bytes >> PAGE_SHIFT);
1848 	/*
1849 	 * Set the number of HW queues we are supporting.
1850 	 */
1851 	if (stor_device->num_sc != 0)
1852 		host->nr_hw_queues = stor_device->num_sc + 1;
1853 
1854 	/*
1855 	 * Set the error handler work queue.
1856 	 */
1857 	host_dev->handle_error_wq =
1858 			alloc_ordered_workqueue("storvsc_error_wq_%d",
1859 						WQ_MEM_RECLAIM,
1860 						host->host_no);
1861 	if (!host_dev->handle_error_wq)
1862 		goto err_out2;
1863 	INIT_WORK(&host_dev->host_scan_work, storvsc_host_scan);
1864 	/* Register the HBA and start the scsi bus scan */
1865 	ret = scsi_add_host(host, &device->device);
1866 	if (ret != 0)
1867 		goto err_out3;
1868 
1869 	if (!dev_is_ide) {
1870 		scsi_scan_host(host);
1871 	} else {
1872 		target = (device->dev_instance.b[5] << 8 |
1873 			 device->dev_instance.b[4]);
1874 		ret = scsi_add_device(host, 0, target, 0);
1875 		if (ret)
1876 			goto err_out4;
1877 	}
1878 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
1879 	if (host->transportt == fc_transport_template) {
1880 		struct fc_rport_identifiers ids = {
1881 			.roles = FC_PORT_ROLE_FCP_DUMMY_INITIATOR,
1882 		};
1883 
1884 		fc_host_node_name(host) = stor_device->node_name;
1885 		fc_host_port_name(host) = stor_device->port_name;
1886 		stor_device->rport = fc_remote_port_add(host, 0, &ids);
1887 		if (!stor_device->rport) {
1888 			ret = -ENOMEM;
1889 			goto err_out4;
1890 		}
1891 	}
1892 #endif
1893 	return 0;
1894 
1895 err_out4:
1896 	scsi_remove_host(host);
1897 
1898 err_out3:
1899 	destroy_workqueue(host_dev->handle_error_wq);
1900 
1901 err_out2:
1902 	/*
1903 	 * Once we have connected with the host, we would need to
1904 	 * to invoke storvsc_dev_remove() to rollback this state and
1905 	 * this call also frees up the stor_device; hence the jump around
1906 	 * err_out1 label.
1907 	 */
1908 	storvsc_dev_remove(device);
1909 	goto err_out0;
1910 
1911 err_out1:
1912 	kfree(stor_device->stor_chns);
1913 	kfree(stor_device);
1914 
1915 err_out0:
1916 	scsi_host_put(host);
1917 	return ret;
1918 }
1919 
1920 static int storvsc_remove(struct hv_device *dev)
1921 {
1922 	struct storvsc_device *stor_device = hv_get_drvdata(dev);
1923 	struct Scsi_Host *host = stor_device->host;
1924 	struct hv_host_device *host_dev = shost_priv(host);
1925 
1926 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
1927 	if (host->transportt == fc_transport_template) {
1928 		fc_remote_port_delete(stor_device->rport);
1929 		fc_remove_host(host);
1930 	}
1931 #endif
1932 	destroy_workqueue(host_dev->handle_error_wq);
1933 	scsi_remove_host(host);
1934 	storvsc_dev_remove(dev);
1935 	scsi_host_put(host);
1936 
1937 	return 0;
1938 }
1939 
1940 static struct hv_driver storvsc_drv = {
1941 	.name = KBUILD_MODNAME,
1942 	.id_table = id_table,
1943 	.probe = storvsc_probe,
1944 	.remove = storvsc_remove,
1945 	.driver = {
1946 		.probe_type = PROBE_PREFER_ASYNCHRONOUS,
1947 	},
1948 };
1949 
1950 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
1951 static struct fc_function_template fc_transport_functions = {
1952 	.show_host_node_name = 1,
1953 	.show_host_port_name = 1,
1954 };
1955 #endif
1956 
1957 static int __init storvsc_drv_init(void)
1958 {
1959 	int ret;
1960 
1961 	/*
1962 	 * Divide the ring buffer data size (which is 1 page less
1963 	 * than the ring buffer size since that page is reserved for
1964 	 * the ring buffer indices) by the max request size (which is
1965 	 * vmbus_channel_packet_multipage_buffer + struct vstor_packet + u64)
1966 	 */
1967 	max_outstanding_req_per_channel =
1968 		((storvsc_ringbuffer_size - PAGE_SIZE) /
1969 		ALIGN(MAX_MULTIPAGE_BUFFER_PACKET +
1970 		sizeof(struct vstor_packet) + sizeof(u64) -
1971 		vmscsi_size_delta,
1972 		sizeof(u64)));
1973 
1974 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
1975 	fc_transport_template = fc_attach_transport(&fc_transport_functions);
1976 	if (!fc_transport_template)
1977 		return -ENODEV;
1978 #endif
1979 
1980 	ret = vmbus_driver_register(&storvsc_drv);
1981 
1982 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
1983 	if (ret)
1984 		fc_release_transport(fc_transport_template);
1985 #endif
1986 
1987 	return ret;
1988 }
1989 
1990 static void __exit storvsc_drv_exit(void)
1991 {
1992 	vmbus_driver_unregister(&storvsc_drv);
1993 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
1994 	fc_release_transport(fc_transport_template);
1995 #endif
1996 }
1997 
1998 MODULE_LICENSE("GPL");
1999 MODULE_DESCRIPTION("Microsoft Hyper-V virtual storage driver");
2000 module_init(storvsc_drv_init);
2001 module_exit(storvsc_drv_exit);
2002