xref: /linux/drivers/scsi/storvsc_drv.c (revision 0da85d1e38b4c186d2248f0239b72d465f5b406c)
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 
45 /*
46  * All wire protocol details (storage protocol between the guest and the host)
47  * are consolidated here.
48  *
49  * Begin protocol definitions.
50  */
51 
52 /*
53  * Version history:
54  * V1 Beta: 0.1
55  * V1 RC < 2008/1/31: 1.0
56  * V1 RC > 2008/1/31:  2.0
57  * Win7: 4.2
58  * Win8: 5.1
59  */
60 
61 
62 #define VMSTOR_WIN7_MAJOR 4
63 #define VMSTOR_WIN7_MINOR 2
64 
65 #define VMSTOR_WIN8_MAJOR 5
66 #define VMSTOR_WIN8_MINOR 1
67 
68 
69 /*  Packet structure describing virtual storage requests. */
70 enum vstor_packet_operation {
71 	VSTOR_OPERATION_COMPLETE_IO		= 1,
72 	VSTOR_OPERATION_REMOVE_DEVICE		= 2,
73 	VSTOR_OPERATION_EXECUTE_SRB		= 3,
74 	VSTOR_OPERATION_RESET_LUN		= 4,
75 	VSTOR_OPERATION_RESET_ADAPTER		= 5,
76 	VSTOR_OPERATION_RESET_BUS		= 6,
77 	VSTOR_OPERATION_BEGIN_INITIALIZATION	= 7,
78 	VSTOR_OPERATION_END_INITIALIZATION	= 8,
79 	VSTOR_OPERATION_QUERY_PROTOCOL_VERSION	= 9,
80 	VSTOR_OPERATION_QUERY_PROPERTIES	= 10,
81 	VSTOR_OPERATION_ENUMERATE_BUS		= 11,
82 	VSTOR_OPERATION_FCHBA_DATA              = 12,
83 	VSTOR_OPERATION_CREATE_SUB_CHANNELS     = 13,
84 	VSTOR_OPERATION_MAXIMUM                 = 13
85 };
86 
87 /*
88  * WWN packet for Fibre Channel HBA
89  */
90 
91 struct hv_fc_wwn_packet {
92 	bool	primary_active;
93 	u8	reserved1;
94 	u8	reserved2;
95 	u8	primary_port_wwn[8];
96 	u8	primary_node_wwn[8];
97 	u8	secondary_port_wwn[8];
98 	u8	secondary_node_wwn[8];
99 };
100 
101 
102 
103 /*
104  * SRB Flag Bits
105  */
106 
107 #define SRB_FLAGS_QUEUE_ACTION_ENABLE		0x00000002
108 #define SRB_FLAGS_DISABLE_DISCONNECT		0x00000004
109 #define SRB_FLAGS_DISABLE_SYNCH_TRANSFER	0x00000008
110 #define SRB_FLAGS_BYPASS_FROZEN_QUEUE		0x00000010
111 #define SRB_FLAGS_DISABLE_AUTOSENSE		0x00000020
112 #define SRB_FLAGS_DATA_IN			0x00000040
113 #define SRB_FLAGS_DATA_OUT			0x00000080
114 #define SRB_FLAGS_NO_DATA_TRANSFER		0x00000000
115 #define SRB_FLAGS_UNSPECIFIED_DIRECTION	(SRB_FLAGS_DATA_IN | SRB_FLAGS_DATA_OUT)
116 #define SRB_FLAGS_NO_QUEUE_FREEZE		0x00000100
117 #define SRB_FLAGS_ADAPTER_CACHE_ENABLE		0x00000200
118 #define SRB_FLAGS_FREE_SENSE_BUFFER		0x00000400
119 
120 /*
121  * This flag indicates the request is part of the workflow for processing a D3.
122  */
123 #define SRB_FLAGS_D3_PROCESSING			0x00000800
124 #define SRB_FLAGS_IS_ACTIVE			0x00010000
125 #define SRB_FLAGS_ALLOCATED_FROM_ZONE		0x00020000
126 #define SRB_FLAGS_SGLIST_FROM_POOL		0x00040000
127 #define SRB_FLAGS_BYPASS_LOCKED_QUEUE		0x00080000
128 #define SRB_FLAGS_NO_KEEP_AWAKE			0x00100000
129 #define SRB_FLAGS_PORT_DRIVER_ALLOCSENSE	0x00200000
130 #define SRB_FLAGS_PORT_DRIVER_SENSEHASPORT	0x00400000
131 #define SRB_FLAGS_DONT_START_NEXT_PACKET	0x00800000
132 #define SRB_FLAGS_PORT_DRIVER_RESERVED		0x0F000000
133 #define SRB_FLAGS_CLASS_DRIVER_RESERVED		0xF0000000
134 
135 
136 /*
137  * Platform neutral description of a scsi request -
138  * this remains the same across the write regardless of 32/64 bit
139  * note: it's patterned off the SCSI_PASS_THROUGH structure
140  */
141 #define STORVSC_MAX_CMD_LEN			0x10
142 
143 #define POST_WIN7_STORVSC_SENSE_BUFFER_SIZE	0x14
144 #define PRE_WIN8_STORVSC_SENSE_BUFFER_SIZE	0x12
145 
146 #define STORVSC_SENSE_BUFFER_SIZE		0x14
147 #define STORVSC_MAX_BUF_LEN_WITH_PADDING	0x14
148 
149 /*
150  * Sense buffer size changed in win8; have a run-time
151  * variable to track the size we should use.
152  */
153 static int sense_buffer_size;
154 
155 /*
156  * The size of the vmscsi_request has changed in win8. The
157  * additional size is because of new elements added to the
158  * structure. These elements are valid only when we are talking
159  * to a win8 host.
160  * Track the correction to size we need to apply.
161  */
162 
163 static int vmscsi_size_delta;
164 static int vmstor_current_major;
165 static int vmstor_current_minor;
166 
167 struct vmscsi_win8_extension {
168 	/*
169 	 * The following were added in Windows 8
170 	 */
171 	u16 reserve;
172 	u8  queue_tag;
173 	u8  queue_action;
174 	u32 srb_flags;
175 	u32 time_out_value;
176 	u32 queue_sort_ey;
177 } __packed;
178 
179 struct vmscsi_request {
180 	u16 length;
181 	u8 srb_status;
182 	u8 scsi_status;
183 
184 	u8  port_number;
185 	u8  path_id;
186 	u8  target_id;
187 	u8  lun;
188 
189 	u8  cdb_length;
190 	u8  sense_info_length;
191 	u8  data_in;
192 	u8  reserved;
193 
194 	u32 data_transfer_length;
195 
196 	union {
197 		u8 cdb[STORVSC_MAX_CMD_LEN];
198 		u8 sense_data[STORVSC_SENSE_BUFFER_SIZE];
199 		u8 reserved_array[STORVSC_MAX_BUF_LEN_WITH_PADDING];
200 	};
201 	/*
202 	 * The following was added in win8.
203 	 */
204 	struct vmscsi_win8_extension win8_extension;
205 
206 } __attribute((packed));
207 
208 
209 /*
210  * This structure is sent during the intialization phase to get the different
211  * properties of the channel.
212  */
213 
214 #define STORAGE_CHANNEL_SUPPORTS_MULTI_CHANNEL		0x1
215 
216 struct vmstorage_channel_properties {
217 	u32 reserved;
218 	u16 max_channel_cnt;
219 	u16 reserved1;
220 
221 	u32 flags;
222 	u32   max_transfer_bytes;
223 
224 	u64  reserved2;
225 } __packed;
226 
227 /*  This structure is sent during the storage protocol negotiations. */
228 struct vmstorage_protocol_version {
229 	/* Major (MSW) and minor (LSW) version numbers. */
230 	u16 major_minor;
231 
232 	/*
233 	 * Revision number is auto-incremented whenever this file is changed
234 	 * (See FILL_VMSTOR_REVISION macro above).  Mismatch does not
235 	 * definitely indicate incompatibility--but it does indicate mismatched
236 	 * builds.
237 	 * This is only used on the windows side. Just set it to 0.
238 	 */
239 	u16 revision;
240 } __packed;
241 
242 /* Channel Property Flags */
243 #define STORAGE_CHANNEL_REMOVABLE_FLAG		0x1
244 #define STORAGE_CHANNEL_EMULATED_IDE_FLAG	0x2
245 
246 struct vstor_packet {
247 	/* Requested operation type */
248 	enum vstor_packet_operation operation;
249 
250 	/*  Flags - see below for values */
251 	u32 flags;
252 
253 	/* Status of the request returned from the server side. */
254 	u32 status;
255 
256 	/* Data payload area */
257 	union {
258 		/*
259 		 * Structure used to forward SCSI commands from the
260 		 * client to the server.
261 		 */
262 		struct vmscsi_request vm_srb;
263 
264 		/* Structure used to query channel properties. */
265 		struct vmstorage_channel_properties storage_channel_properties;
266 
267 		/* Used during version negotiations. */
268 		struct vmstorage_protocol_version version;
269 
270 		/* Fibre channel address packet */
271 		struct hv_fc_wwn_packet wwn_packet;
272 
273 		/* Number of sub-channels to create */
274 		u16 sub_channel_count;
275 
276 		/* This will be the maximum of the union members */
277 		u8  buffer[0x34];
278 	};
279 } __packed;
280 
281 /*
282  * Packet Flags:
283  *
284  * This flag indicates that the server should send back a completion for this
285  * packet.
286  */
287 
288 #define REQUEST_COMPLETION_FLAG	0x1
289 
290 /* Matches Windows-end */
291 enum storvsc_request_type {
292 	WRITE_TYPE = 0,
293 	READ_TYPE,
294 	UNKNOWN_TYPE,
295 };
296 
297 /*
298  * SRB status codes and masks; a subset of the codes used here.
299  */
300 
301 #define SRB_STATUS_AUTOSENSE_VALID	0x80
302 #define SRB_STATUS_INVALID_LUN	0x20
303 #define SRB_STATUS_SUCCESS	0x01
304 #define SRB_STATUS_ABORTED	0x02
305 #define SRB_STATUS_ERROR	0x04
306 
307 /*
308  * This is the end of Protocol specific defines.
309  */
310 
311 static int storvsc_ringbuffer_size = (256 * PAGE_SIZE);
312 static u32 max_outstanding_req_per_channel;
313 
314 static int storvsc_vcpus_per_sub_channel = 4;
315 
316 module_param(storvsc_ringbuffer_size, int, S_IRUGO);
317 MODULE_PARM_DESC(storvsc_ringbuffer_size, "Ring buffer size (bytes)");
318 
319 module_param(storvsc_vcpus_per_sub_channel, int, S_IRUGO);
320 MODULE_PARM_DESC(vcpus_per_sub_channel, "Ratio of VCPUs to subchannels");
321 /*
322  * Timeout in seconds for all devices managed by this driver.
323  */
324 static int storvsc_timeout = 180;
325 
326 static int msft_blist_flags = BLIST_TRY_VPD_PAGES;
327 
328 
329 static void storvsc_on_channel_callback(void *context);
330 
331 #define STORVSC_MAX_LUNS_PER_TARGET			255
332 #define STORVSC_MAX_TARGETS				2
333 #define STORVSC_MAX_CHANNELS				8
334 
335 #define STORVSC_FC_MAX_LUNS_PER_TARGET			255
336 #define STORVSC_FC_MAX_TARGETS				128
337 #define STORVSC_FC_MAX_CHANNELS				8
338 
339 #define STORVSC_IDE_MAX_LUNS_PER_TARGET			64
340 #define STORVSC_IDE_MAX_TARGETS				1
341 #define STORVSC_IDE_MAX_CHANNELS			1
342 
343 struct storvsc_cmd_request {
344 	struct scsi_cmnd *cmd;
345 
346 	unsigned int bounce_sgl_count;
347 	struct scatterlist *bounce_sgl;
348 
349 	struct hv_device *device;
350 
351 	/* Synchronize the request/response if needed */
352 	struct completion wait_event;
353 
354 	struct vmbus_channel_packet_multipage_buffer mpb;
355 	struct vmbus_packet_mpb_array *payload;
356 	u32 payload_sz;
357 
358 	struct vstor_packet vstor_packet;
359 };
360 
361 
362 /* A storvsc device is a device object that contains a vmbus channel */
363 struct storvsc_device {
364 	struct hv_device *device;
365 
366 	bool	 destroy;
367 	bool	 drain_notify;
368 	bool	 open_sub_channel;
369 	atomic_t num_outstanding_req;
370 	struct Scsi_Host *host;
371 
372 	wait_queue_head_t waiting_to_drain;
373 
374 	/*
375 	 * Each unique Port/Path/Target represents 1 channel ie scsi
376 	 * controller. In reality, the pathid, targetid is always 0
377 	 * and the port is set by us
378 	 */
379 	unsigned int port_number;
380 	unsigned char path_id;
381 	unsigned char target_id;
382 
383 	/*
384 	 * Max I/O, the device can support.
385 	 */
386 	u32   max_transfer_bytes;
387 	/* Used for vsc/vsp channel reset process */
388 	struct storvsc_cmd_request init_request;
389 	struct storvsc_cmd_request reset_request;
390 };
391 
392 struct hv_host_device {
393 	struct hv_device *dev;
394 	unsigned int port;
395 	unsigned char path;
396 	unsigned char target;
397 };
398 
399 struct storvsc_scan_work {
400 	struct work_struct work;
401 	struct Scsi_Host *host;
402 	uint lun;
403 };
404 
405 static void storvsc_device_scan(struct work_struct *work)
406 {
407 	struct storvsc_scan_work *wrk;
408 	uint lun;
409 	struct scsi_device *sdev;
410 
411 	wrk = container_of(work, struct storvsc_scan_work, work);
412 	lun = wrk->lun;
413 
414 	sdev = scsi_device_lookup(wrk->host, 0, 0, lun);
415 	if (!sdev)
416 		goto done;
417 	scsi_rescan_device(&sdev->sdev_gendev);
418 	scsi_device_put(sdev);
419 
420 done:
421 	kfree(wrk);
422 }
423 
424 static void storvsc_host_scan(struct work_struct *work)
425 {
426 	struct storvsc_scan_work *wrk;
427 	struct Scsi_Host *host;
428 	struct scsi_device *sdev;
429 	unsigned long flags;
430 
431 	wrk = container_of(work, struct storvsc_scan_work, work);
432 	host = wrk->host;
433 
434 	/*
435 	 * Before scanning the host, first check to see if any of the
436 	 * currrently known devices have been hot removed. We issue a
437 	 * "unit ready" command against all currently known devices.
438 	 * This I/O will result in an error for devices that have been
439 	 * removed. As part of handling the I/O error, we remove the device.
440 	 *
441 	 * When a LUN is added or removed, the host sends us a signal to
442 	 * scan the host. Thus we are forced to discover the LUNs that
443 	 * may have been removed this way.
444 	 */
445 	mutex_lock(&host->scan_mutex);
446 	spin_lock_irqsave(host->host_lock, flags);
447 	list_for_each_entry(sdev, &host->__devices, siblings) {
448 		spin_unlock_irqrestore(host->host_lock, flags);
449 		scsi_test_unit_ready(sdev, 1, 1, NULL);
450 		spin_lock_irqsave(host->host_lock, flags);
451 		continue;
452 	}
453 	spin_unlock_irqrestore(host->host_lock, flags);
454 	mutex_unlock(&host->scan_mutex);
455 	/*
456 	 * Now scan the host to discover LUNs that may have been added.
457 	 */
458 	scsi_scan_host(host);
459 
460 	kfree(wrk);
461 }
462 
463 static void storvsc_remove_lun(struct work_struct *work)
464 {
465 	struct storvsc_scan_work *wrk;
466 	struct scsi_device *sdev;
467 
468 	wrk = container_of(work, struct storvsc_scan_work, work);
469 	if (!scsi_host_get(wrk->host))
470 		goto done;
471 
472 	sdev = scsi_device_lookup(wrk->host, 0, 0, wrk->lun);
473 
474 	if (sdev) {
475 		scsi_remove_device(sdev);
476 		scsi_device_put(sdev);
477 	}
478 	scsi_host_put(wrk->host);
479 
480 done:
481 	kfree(wrk);
482 }
483 
484 /*
485  * Major/minor macros.  Minor version is in LSB, meaning that earlier flat
486  * version numbers will be interpreted as "0.x" (i.e., 1 becomes 0.1).
487  */
488 
489 static inline u16 storvsc_get_version(u8 major, u8 minor)
490 {
491 	u16 version;
492 
493 	version = ((major << 8) | minor);
494 	return version;
495 }
496 
497 /*
498  * We can get incoming messages from the host that are not in response to
499  * messages that we have sent out. An example of this would be messages
500  * received by the guest to notify dynamic addition/removal of LUNs. To
501  * deal with potential race conditions where the driver may be in the
502  * midst of being unloaded when we might receive an unsolicited message
503  * from the host, we have implemented a mechanism to gurantee sequential
504  * consistency:
505  *
506  * 1) Once the device is marked as being destroyed, we will fail all
507  *    outgoing messages.
508  * 2) We permit incoming messages when the device is being destroyed,
509  *    only to properly account for messages already sent out.
510  */
511 
512 static inline struct storvsc_device *get_out_stor_device(
513 					struct hv_device *device)
514 {
515 	struct storvsc_device *stor_device;
516 
517 	stor_device = hv_get_drvdata(device);
518 
519 	if (stor_device && stor_device->destroy)
520 		stor_device = NULL;
521 
522 	return stor_device;
523 }
524 
525 
526 static inline void storvsc_wait_to_drain(struct storvsc_device *dev)
527 {
528 	dev->drain_notify = true;
529 	wait_event(dev->waiting_to_drain,
530 		   atomic_read(&dev->num_outstanding_req) == 0);
531 	dev->drain_notify = false;
532 }
533 
534 static inline struct storvsc_device *get_in_stor_device(
535 					struct hv_device *device)
536 {
537 	struct storvsc_device *stor_device;
538 
539 	stor_device = hv_get_drvdata(device);
540 
541 	if (!stor_device)
542 		goto get_in_err;
543 
544 	/*
545 	 * If the device is being destroyed; allow incoming
546 	 * traffic only to cleanup outstanding requests.
547 	 */
548 
549 	if (stor_device->destroy  &&
550 		(atomic_read(&stor_device->num_outstanding_req) == 0))
551 		stor_device = NULL;
552 
553 get_in_err:
554 	return stor_device;
555 
556 }
557 
558 static void destroy_bounce_buffer(struct scatterlist *sgl,
559 				  unsigned int sg_count)
560 {
561 	int i;
562 	struct page *page_buf;
563 
564 	for (i = 0; i < sg_count; i++) {
565 		page_buf = sg_page((&sgl[i]));
566 		if (page_buf != NULL)
567 			__free_page(page_buf);
568 	}
569 
570 	kfree(sgl);
571 }
572 
573 static int do_bounce_buffer(struct scatterlist *sgl, unsigned int sg_count)
574 {
575 	int i;
576 
577 	/* No need to check */
578 	if (sg_count < 2)
579 		return -1;
580 
581 	/* We have at least 2 sg entries */
582 	for (i = 0; i < sg_count; i++) {
583 		if (i == 0) {
584 			/* make sure 1st one does not have hole */
585 			if (sgl[i].offset + sgl[i].length != PAGE_SIZE)
586 				return i;
587 		} else if (i == sg_count - 1) {
588 			/* make sure last one does not have hole */
589 			if (sgl[i].offset != 0)
590 				return i;
591 		} else {
592 			/* make sure no hole in the middle */
593 			if (sgl[i].length != PAGE_SIZE || sgl[i].offset != 0)
594 				return i;
595 		}
596 	}
597 	return -1;
598 }
599 
600 static struct scatterlist *create_bounce_buffer(struct scatterlist *sgl,
601 						unsigned int sg_count,
602 						unsigned int len,
603 						int write)
604 {
605 	int i;
606 	int num_pages;
607 	struct scatterlist *bounce_sgl;
608 	struct page *page_buf;
609 	unsigned int buf_len = ((write == WRITE_TYPE) ? 0 : PAGE_SIZE);
610 
611 	num_pages = ALIGN(len, PAGE_SIZE) >> PAGE_SHIFT;
612 
613 	bounce_sgl = kcalloc(num_pages, sizeof(struct scatterlist), GFP_ATOMIC);
614 	if (!bounce_sgl)
615 		return NULL;
616 
617 	sg_init_table(bounce_sgl, num_pages);
618 	for (i = 0; i < num_pages; i++) {
619 		page_buf = alloc_page(GFP_ATOMIC);
620 		if (!page_buf)
621 			goto cleanup;
622 		sg_set_page(&bounce_sgl[i], page_buf, buf_len, 0);
623 	}
624 
625 	return bounce_sgl;
626 
627 cleanup:
628 	destroy_bounce_buffer(bounce_sgl, num_pages);
629 	return NULL;
630 }
631 
632 /* Assume the original sgl has enough room */
633 static unsigned int copy_from_bounce_buffer(struct scatterlist *orig_sgl,
634 					    struct scatterlist *bounce_sgl,
635 					    unsigned int orig_sgl_count,
636 					    unsigned int bounce_sgl_count)
637 {
638 	int i;
639 	int j = 0;
640 	unsigned long src, dest;
641 	unsigned int srclen, destlen, copylen;
642 	unsigned int total_copied = 0;
643 	unsigned long bounce_addr = 0;
644 	unsigned long dest_addr = 0;
645 	unsigned long flags;
646 	struct scatterlist *cur_dest_sgl;
647 	struct scatterlist *cur_src_sgl;
648 
649 	local_irq_save(flags);
650 	cur_dest_sgl = orig_sgl;
651 	cur_src_sgl = bounce_sgl;
652 	for (i = 0; i < orig_sgl_count; i++) {
653 		dest_addr = (unsigned long)
654 				kmap_atomic(sg_page(cur_dest_sgl)) +
655 				cur_dest_sgl->offset;
656 		dest = dest_addr;
657 		destlen = cur_dest_sgl->length;
658 
659 		if (bounce_addr == 0)
660 			bounce_addr = (unsigned long)kmap_atomic(
661 							sg_page(cur_src_sgl));
662 
663 		while (destlen) {
664 			src = bounce_addr + cur_src_sgl->offset;
665 			srclen = cur_src_sgl->length - cur_src_sgl->offset;
666 
667 			copylen = min(srclen, destlen);
668 			memcpy((void *)dest, (void *)src, copylen);
669 
670 			total_copied += copylen;
671 			cur_src_sgl->offset += copylen;
672 			destlen -= copylen;
673 			dest += copylen;
674 
675 			if (cur_src_sgl->offset == cur_src_sgl->length) {
676 				/* full */
677 				kunmap_atomic((void *)bounce_addr);
678 				j++;
679 
680 				/*
681 				 * It is possible that the number of elements
682 				 * in the bounce buffer may not be equal to
683 				 * the number of elements in the original
684 				 * scatter list. Handle this correctly.
685 				 */
686 
687 				if (j == bounce_sgl_count) {
688 					/*
689 					 * We are done; cleanup and return.
690 					 */
691 					kunmap_atomic((void *)(dest_addr -
692 						cur_dest_sgl->offset));
693 					local_irq_restore(flags);
694 					return total_copied;
695 				}
696 
697 				/* if we need to use another bounce buffer */
698 				if (destlen || i != orig_sgl_count - 1) {
699 					cur_src_sgl = sg_next(cur_src_sgl);
700 					bounce_addr = (unsigned long)
701 							kmap_atomic(
702 							sg_page(cur_src_sgl));
703 				}
704 			} else if (destlen == 0 && i == orig_sgl_count - 1) {
705 				/* unmap the last bounce that is < PAGE_SIZE */
706 				kunmap_atomic((void *)bounce_addr);
707 			}
708 		}
709 
710 		kunmap_atomic((void *)(dest_addr - cur_dest_sgl->offset));
711 		cur_dest_sgl = sg_next(cur_dest_sgl);
712 	}
713 
714 	local_irq_restore(flags);
715 
716 	return total_copied;
717 }
718 
719 /* Assume the bounce_sgl has enough room ie using the create_bounce_buffer() */
720 static unsigned int copy_to_bounce_buffer(struct scatterlist *orig_sgl,
721 					  struct scatterlist *bounce_sgl,
722 					  unsigned int orig_sgl_count)
723 {
724 	int i;
725 	int j = 0;
726 	unsigned long src, dest;
727 	unsigned int srclen, destlen, copylen;
728 	unsigned int total_copied = 0;
729 	unsigned long bounce_addr = 0;
730 	unsigned long src_addr = 0;
731 	unsigned long flags;
732 	struct scatterlist *cur_src_sgl;
733 	struct scatterlist *cur_dest_sgl;
734 
735 	local_irq_save(flags);
736 
737 	cur_src_sgl = orig_sgl;
738 	cur_dest_sgl = bounce_sgl;
739 
740 	for (i = 0; i < orig_sgl_count; i++) {
741 		src_addr = (unsigned long)
742 				kmap_atomic(sg_page(cur_src_sgl)) +
743 				cur_src_sgl->offset;
744 		src = src_addr;
745 		srclen = cur_src_sgl->length;
746 
747 		if (bounce_addr == 0)
748 			bounce_addr = (unsigned long)
749 					kmap_atomic(sg_page(cur_dest_sgl));
750 
751 		while (srclen) {
752 			/* assume bounce offset always == 0 */
753 			dest = bounce_addr + cur_dest_sgl->length;
754 			destlen = PAGE_SIZE - cur_dest_sgl->length;
755 
756 			copylen = min(srclen, destlen);
757 			memcpy((void *)dest, (void *)src, copylen);
758 
759 			total_copied += copylen;
760 			cur_dest_sgl->length += copylen;
761 			srclen -= copylen;
762 			src += copylen;
763 
764 			if (cur_dest_sgl->length == PAGE_SIZE) {
765 				/* full..move to next entry */
766 				kunmap_atomic((void *)bounce_addr);
767 				bounce_addr = 0;
768 				j++;
769 			}
770 
771 			/* if we need to use another bounce buffer */
772 			if (srclen && bounce_addr == 0) {
773 				cur_dest_sgl = sg_next(cur_dest_sgl);
774 				bounce_addr = (unsigned long)
775 						kmap_atomic(
776 						sg_page(cur_dest_sgl));
777 			}
778 
779 		}
780 
781 		kunmap_atomic((void *)(src_addr - cur_src_sgl->offset));
782 		cur_src_sgl = sg_next(cur_src_sgl);
783 	}
784 
785 	if (bounce_addr)
786 		kunmap_atomic((void *)bounce_addr);
787 
788 	local_irq_restore(flags);
789 
790 	return total_copied;
791 }
792 
793 static void handle_sc_creation(struct vmbus_channel *new_sc)
794 {
795 	struct hv_device *device = new_sc->primary_channel->device_obj;
796 	struct storvsc_device *stor_device;
797 	struct vmstorage_channel_properties props;
798 
799 	stor_device = get_out_stor_device(device);
800 	if (!stor_device)
801 		return;
802 
803 	if (stor_device->open_sub_channel == false)
804 		return;
805 
806 	memset(&props, 0, sizeof(struct vmstorage_channel_properties));
807 
808 	vmbus_open(new_sc,
809 		   storvsc_ringbuffer_size,
810 		   storvsc_ringbuffer_size,
811 		   (void *)&props,
812 		   sizeof(struct vmstorage_channel_properties),
813 		   storvsc_on_channel_callback, new_sc);
814 }
815 
816 static void  handle_multichannel_storage(struct hv_device *device, int max_chns)
817 {
818 	struct storvsc_device *stor_device;
819 	int num_cpus = num_online_cpus();
820 	int num_sc;
821 	struct storvsc_cmd_request *request;
822 	struct vstor_packet *vstor_packet;
823 	int ret, t;
824 
825 	num_sc = ((max_chns > num_cpus) ? num_cpus : max_chns);
826 	stor_device = get_out_stor_device(device);
827 	if (!stor_device)
828 		return;
829 
830 	request = &stor_device->init_request;
831 	vstor_packet = &request->vstor_packet;
832 
833 	stor_device->open_sub_channel = true;
834 	/*
835 	 * Establish a handler for dealing with subchannels.
836 	 */
837 	vmbus_set_sc_create_callback(device->channel, handle_sc_creation);
838 
839 	/*
840 	 * Check to see if sub-channels have already been created. This
841 	 * can happen when this driver is re-loaded after unloading.
842 	 */
843 
844 	if (vmbus_are_subchannels_present(device->channel))
845 		return;
846 
847 	stor_device->open_sub_channel = false;
848 	/*
849 	 * Request the host to create sub-channels.
850 	 */
851 	memset(request, 0, sizeof(struct storvsc_cmd_request));
852 	init_completion(&request->wait_event);
853 	vstor_packet->operation = VSTOR_OPERATION_CREATE_SUB_CHANNELS;
854 	vstor_packet->flags = REQUEST_COMPLETION_FLAG;
855 	vstor_packet->sub_channel_count = num_sc;
856 
857 	ret = vmbus_sendpacket(device->channel, vstor_packet,
858 			       (sizeof(struct vstor_packet) -
859 			       vmscsi_size_delta),
860 			       (unsigned long)request,
861 			       VM_PKT_DATA_INBAND,
862 			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
863 
864 	if (ret != 0)
865 		return;
866 
867 	t = wait_for_completion_timeout(&request->wait_event, 10*HZ);
868 	if (t == 0)
869 		return;
870 
871 	if (vstor_packet->operation != VSTOR_OPERATION_COMPLETE_IO ||
872 	    vstor_packet->status != 0)
873 		return;
874 
875 	/*
876 	 * Now that we created the sub-channels, invoke the check; this
877 	 * may trigger the callback.
878 	 */
879 	stor_device->open_sub_channel = true;
880 	vmbus_are_subchannels_present(device->channel);
881 }
882 
883 static int storvsc_channel_init(struct hv_device *device)
884 {
885 	struct storvsc_device *stor_device;
886 	struct storvsc_cmd_request *request;
887 	struct vstor_packet *vstor_packet;
888 	int ret, t;
889 	int max_chns;
890 	bool process_sub_channels = false;
891 
892 	stor_device = get_out_stor_device(device);
893 	if (!stor_device)
894 		return -ENODEV;
895 
896 	request = &stor_device->init_request;
897 	vstor_packet = &request->vstor_packet;
898 
899 	/*
900 	 * Now, initiate the vsc/vsp initialization protocol on the open
901 	 * channel
902 	 */
903 	memset(request, 0, sizeof(struct storvsc_cmd_request));
904 	init_completion(&request->wait_event);
905 	vstor_packet->operation = VSTOR_OPERATION_BEGIN_INITIALIZATION;
906 	vstor_packet->flags = REQUEST_COMPLETION_FLAG;
907 
908 	ret = vmbus_sendpacket(device->channel, vstor_packet,
909 			       (sizeof(struct vstor_packet) -
910 			       vmscsi_size_delta),
911 			       (unsigned long)request,
912 			       VM_PKT_DATA_INBAND,
913 			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
914 	if (ret != 0)
915 		goto cleanup;
916 
917 	t = wait_for_completion_timeout(&request->wait_event, 5*HZ);
918 	if (t == 0) {
919 		ret = -ETIMEDOUT;
920 		goto cleanup;
921 	}
922 
923 	if (vstor_packet->operation != VSTOR_OPERATION_COMPLETE_IO ||
924 	    vstor_packet->status != 0)
925 		goto cleanup;
926 
927 
928 	/* reuse the packet for version range supported */
929 	memset(vstor_packet, 0, sizeof(struct vstor_packet));
930 	vstor_packet->operation = VSTOR_OPERATION_QUERY_PROTOCOL_VERSION;
931 	vstor_packet->flags = REQUEST_COMPLETION_FLAG;
932 
933 	vstor_packet->version.major_minor =
934 		storvsc_get_version(vmstor_current_major, vmstor_current_minor);
935 
936 	/*
937 	 * The revision number is only used in Windows; set it to 0.
938 	 */
939 	vstor_packet->version.revision = 0;
940 
941 	ret = vmbus_sendpacket(device->channel, vstor_packet,
942 			       (sizeof(struct vstor_packet) -
943 				vmscsi_size_delta),
944 			       (unsigned long)request,
945 			       VM_PKT_DATA_INBAND,
946 			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
947 	if (ret != 0)
948 		goto cleanup;
949 
950 	t = wait_for_completion_timeout(&request->wait_event, 5*HZ);
951 	if (t == 0) {
952 		ret = -ETIMEDOUT;
953 		goto cleanup;
954 	}
955 
956 	if (vstor_packet->operation != VSTOR_OPERATION_COMPLETE_IO ||
957 	    vstor_packet->status != 0)
958 		goto cleanup;
959 
960 
961 	memset(vstor_packet, 0, sizeof(struct vstor_packet));
962 	vstor_packet->operation = VSTOR_OPERATION_QUERY_PROPERTIES;
963 	vstor_packet->flags = REQUEST_COMPLETION_FLAG;
964 
965 	ret = vmbus_sendpacket(device->channel, vstor_packet,
966 			       (sizeof(struct vstor_packet) -
967 				vmscsi_size_delta),
968 			       (unsigned long)request,
969 			       VM_PKT_DATA_INBAND,
970 			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
971 
972 	if (ret != 0)
973 		goto cleanup;
974 
975 	t = wait_for_completion_timeout(&request->wait_event, 5*HZ);
976 	if (t == 0) {
977 		ret = -ETIMEDOUT;
978 		goto cleanup;
979 	}
980 
981 	if (vstor_packet->operation != VSTOR_OPERATION_COMPLETE_IO ||
982 	    vstor_packet->status != 0)
983 		goto cleanup;
984 
985 	/*
986 	 * Check to see if multi-channel support is there.
987 	 * Hosts that implement protocol version of 5.1 and above
988 	 * support multi-channel.
989 	 */
990 	max_chns = vstor_packet->storage_channel_properties.max_channel_cnt;
991 	if ((vmbus_proto_version != VERSION_WIN7) &&
992 	   (vmbus_proto_version != VERSION_WS2008))  {
993 		if (vstor_packet->storage_channel_properties.flags &
994 		    STORAGE_CHANNEL_SUPPORTS_MULTI_CHANNEL)
995 			process_sub_channels = true;
996 	}
997 	stor_device->max_transfer_bytes =
998 		vstor_packet->storage_channel_properties.max_transfer_bytes;
999 
1000 	memset(vstor_packet, 0, sizeof(struct vstor_packet));
1001 	vstor_packet->operation = VSTOR_OPERATION_END_INITIALIZATION;
1002 	vstor_packet->flags = REQUEST_COMPLETION_FLAG;
1003 
1004 	ret = vmbus_sendpacket(device->channel, vstor_packet,
1005 			       (sizeof(struct vstor_packet) -
1006 				vmscsi_size_delta),
1007 			       (unsigned long)request,
1008 			       VM_PKT_DATA_INBAND,
1009 			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
1010 
1011 	if (ret != 0)
1012 		goto cleanup;
1013 
1014 	t = wait_for_completion_timeout(&request->wait_event, 5*HZ);
1015 	if (t == 0) {
1016 		ret = -ETIMEDOUT;
1017 		goto cleanup;
1018 	}
1019 
1020 	if (vstor_packet->operation != VSTOR_OPERATION_COMPLETE_IO ||
1021 	    vstor_packet->status != 0)
1022 		goto cleanup;
1023 
1024 	if (process_sub_channels)
1025 		handle_multichannel_storage(device, max_chns);
1026 
1027 
1028 cleanup:
1029 	return ret;
1030 }
1031 
1032 static void storvsc_handle_error(struct vmscsi_request *vm_srb,
1033 				struct scsi_cmnd *scmnd,
1034 				struct Scsi_Host *host,
1035 				u8 asc, u8 ascq)
1036 {
1037 	struct storvsc_scan_work *wrk;
1038 	void (*process_err_fn)(struct work_struct *work);
1039 	bool do_work = false;
1040 
1041 	switch (vm_srb->srb_status) {
1042 	case SRB_STATUS_ERROR:
1043 		/*
1044 		 * If there is an error; offline the device since all
1045 		 * error recovery strategies would have already been
1046 		 * deployed on the host side. However, if the command
1047 		 * were a pass-through command deal with it appropriately.
1048 		 */
1049 		switch (scmnd->cmnd[0]) {
1050 		case ATA_16:
1051 		case ATA_12:
1052 			set_host_byte(scmnd, DID_PASSTHROUGH);
1053 			break;
1054 		/*
1055 		 * On Some Windows hosts TEST_UNIT_READY command can return
1056 		 * SRB_STATUS_ERROR, let the upper level code deal with it
1057 		 * based on the sense information.
1058 		 */
1059 		case TEST_UNIT_READY:
1060 			break;
1061 		default:
1062 			set_host_byte(scmnd, DID_TARGET_FAILURE);
1063 		}
1064 		break;
1065 	case SRB_STATUS_INVALID_LUN:
1066 		do_work = true;
1067 		process_err_fn = storvsc_remove_lun;
1068 		break;
1069 	case (SRB_STATUS_ABORTED | SRB_STATUS_AUTOSENSE_VALID):
1070 		if ((asc == 0x2a) && (ascq == 0x9)) {
1071 			do_work = true;
1072 			process_err_fn = storvsc_device_scan;
1073 			/*
1074 			 * Retry the I/O that trigerred this.
1075 			 */
1076 			set_host_byte(scmnd, DID_REQUEUE);
1077 		}
1078 		break;
1079 	}
1080 
1081 	if (!do_work)
1082 		return;
1083 
1084 	/*
1085 	 * We need to schedule work to process this error; schedule it.
1086 	 */
1087 	wrk = kmalloc(sizeof(struct storvsc_scan_work), GFP_ATOMIC);
1088 	if (!wrk) {
1089 		set_host_byte(scmnd, DID_TARGET_FAILURE);
1090 		return;
1091 	}
1092 
1093 	wrk->host = host;
1094 	wrk->lun = vm_srb->lun;
1095 	INIT_WORK(&wrk->work, process_err_fn);
1096 	schedule_work(&wrk->work);
1097 }
1098 
1099 
1100 static void storvsc_command_completion(struct storvsc_cmd_request *cmd_request)
1101 {
1102 	struct scsi_cmnd *scmnd = cmd_request->cmd;
1103 	struct hv_host_device *host_dev = shost_priv(scmnd->device->host);
1104 	struct scsi_sense_hdr sense_hdr;
1105 	struct vmscsi_request *vm_srb;
1106 	struct Scsi_Host *host;
1107 	struct storvsc_device *stor_dev;
1108 	struct hv_device *dev = host_dev->dev;
1109 	u32 payload_sz = cmd_request->payload_sz;
1110 	void *payload = cmd_request->payload;
1111 
1112 	stor_dev = get_in_stor_device(dev);
1113 	host = stor_dev->host;
1114 
1115 	vm_srb = &cmd_request->vstor_packet.vm_srb;
1116 	if (cmd_request->bounce_sgl_count) {
1117 		if (vm_srb->data_in == READ_TYPE)
1118 			copy_from_bounce_buffer(scsi_sglist(scmnd),
1119 					cmd_request->bounce_sgl,
1120 					scsi_sg_count(scmnd),
1121 					cmd_request->bounce_sgl_count);
1122 		destroy_bounce_buffer(cmd_request->bounce_sgl,
1123 					cmd_request->bounce_sgl_count);
1124 	}
1125 
1126 	scmnd->result = vm_srb->scsi_status;
1127 
1128 	if (scmnd->result) {
1129 		if (scsi_normalize_sense(scmnd->sense_buffer,
1130 				SCSI_SENSE_BUFFERSIZE, &sense_hdr))
1131 			scsi_print_sense_hdr(scmnd->device, "storvsc",
1132 					     &sense_hdr);
1133 	}
1134 
1135 	if (vm_srb->srb_status != SRB_STATUS_SUCCESS)
1136 		storvsc_handle_error(vm_srb, scmnd, host, sense_hdr.asc,
1137 					 sense_hdr.ascq);
1138 
1139 	scsi_set_resid(scmnd,
1140 		cmd_request->payload->range.len -
1141 		vm_srb->data_transfer_length);
1142 
1143 	scmnd->scsi_done(scmnd);
1144 
1145 	if (payload_sz >
1146 		sizeof(struct vmbus_channel_packet_multipage_buffer))
1147 		kfree(payload);
1148 }
1149 
1150 static void storvsc_on_io_completion(struct hv_device *device,
1151 				  struct vstor_packet *vstor_packet,
1152 				  struct storvsc_cmd_request *request)
1153 {
1154 	struct storvsc_device *stor_device;
1155 	struct vstor_packet *stor_pkt;
1156 
1157 	stor_device = hv_get_drvdata(device);
1158 	stor_pkt = &request->vstor_packet;
1159 
1160 	/*
1161 	 * The current SCSI handling on the host side does
1162 	 * not correctly handle:
1163 	 * INQUIRY command with page code parameter set to 0x80
1164 	 * MODE_SENSE command with cmd[2] == 0x1c
1165 	 *
1166 	 * Setup srb and scsi status so this won't be fatal.
1167 	 * We do this so we can distinguish truly fatal failues
1168 	 * (srb status == 0x4) and off-line the device in that case.
1169 	 */
1170 
1171 	if ((stor_pkt->vm_srb.cdb[0] == INQUIRY) ||
1172 	   (stor_pkt->vm_srb.cdb[0] == MODE_SENSE)) {
1173 		vstor_packet->vm_srb.scsi_status = 0;
1174 		vstor_packet->vm_srb.srb_status = SRB_STATUS_SUCCESS;
1175 	}
1176 
1177 
1178 	/* Copy over the status...etc */
1179 	stor_pkt->vm_srb.scsi_status = vstor_packet->vm_srb.scsi_status;
1180 	stor_pkt->vm_srb.srb_status = vstor_packet->vm_srb.srb_status;
1181 	stor_pkt->vm_srb.sense_info_length =
1182 	vstor_packet->vm_srb.sense_info_length;
1183 
1184 
1185 	if ((vstor_packet->vm_srb.scsi_status & 0xFF) == 0x02) {
1186 		/* CHECK_CONDITION */
1187 		if (vstor_packet->vm_srb.srb_status &
1188 			SRB_STATUS_AUTOSENSE_VALID) {
1189 			/* autosense data available */
1190 
1191 			memcpy(request->cmd->sense_buffer,
1192 			       vstor_packet->vm_srb.sense_data,
1193 			       vstor_packet->vm_srb.sense_info_length);
1194 
1195 		}
1196 	}
1197 
1198 	stor_pkt->vm_srb.data_transfer_length =
1199 	vstor_packet->vm_srb.data_transfer_length;
1200 
1201 	storvsc_command_completion(request);
1202 
1203 	if (atomic_dec_and_test(&stor_device->num_outstanding_req) &&
1204 		stor_device->drain_notify)
1205 		wake_up(&stor_device->waiting_to_drain);
1206 
1207 
1208 }
1209 
1210 static void storvsc_on_receive(struct hv_device *device,
1211 			     struct vstor_packet *vstor_packet,
1212 			     struct storvsc_cmd_request *request)
1213 {
1214 	struct storvsc_scan_work *work;
1215 	struct storvsc_device *stor_device;
1216 
1217 	switch (vstor_packet->operation) {
1218 	case VSTOR_OPERATION_COMPLETE_IO:
1219 		storvsc_on_io_completion(device, vstor_packet, request);
1220 		break;
1221 
1222 	case VSTOR_OPERATION_REMOVE_DEVICE:
1223 	case VSTOR_OPERATION_ENUMERATE_BUS:
1224 		stor_device = get_in_stor_device(device);
1225 		work = kmalloc(sizeof(struct storvsc_scan_work), GFP_ATOMIC);
1226 		if (!work)
1227 			return;
1228 
1229 		INIT_WORK(&work->work, storvsc_host_scan);
1230 		work->host = stor_device->host;
1231 		schedule_work(&work->work);
1232 		break;
1233 
1234 	default:
1235 		break;
1236 	}
1237 }
1238 
1239 static void storvsc_on_channel_callback(void *context)
1240 {
1241 	struct vmbus_channel *channel = (struct vmbus_channel *)context;
1242 	struct hv_device *device;
1243 	struct storvsc_device *stor_device;
1244 	u32 bytes_recvd;
1245 	u64 request_id;
1246 	unsigned char packet[ALIGN(sizeof(struct vstor_packet), 8)];
1247 	struct storvsc_cmd_request *request;
1248 	int ret;
1249 
1250 	if (channel->primary_channel != NULL)
1251 		device = channel->primary_channel->device_obj;
1252 	else
1253 		device = channel->device_obj;
1254 
1255 	stor_device = get_in_stor_device(device);
1256 	if (!stor_device)
1257 		return;
1258 
1259 	do {
1260 		ret = vmbus_recvpacket(channel, packet,
1261 				       ALIGN((sizeof(struct vstor_packet) -
1262 					     vmscsi_size_delta), 8),
1263 				       &bytes_recvd, &request_id);
1264 		if (ret == 0 && bytes_recvd > 0) {
1265 
1266 			request = (struct storvsc_cmd_request *)
1267 					(unsigned long)request_id;
1268 
1269 			if ((request == &stor_device->init_request) ||
1270 			    (request == &stor_device->reset_request)) {
1271 
1272 				memcpy(&request->vstor_packet, packet,
1273 				       (sizeof(struct vstor_packet) -
1274 					vmscsi_size_delta));
1275 				complete(&request->wait_event);
1276 			} else {
1277 				storvsc_on_receive(device,
1278 						(struct vstor_packet *)packet,
1279 						request);
1280 			}
1281 		} else {
1282 			break;
1283 		}
1284 	} while (1);
1285 
1286 	return;
1287 }
1288 
1289 static int storvsc_connect_to_vsp(struct hv_device *device, u32 ring_size)
1290 {
1291 	struct vmstorage_channel_properties props;
1292 	int ret;
1293 
1294 	memset(&props, 0, sizeof(struct vmstorage_channel_properties));
1295 
1296 	ret = vmbus_open(device->channel,
1297 			 ring_size,
1298 			 ring_size,
1299 			 (void *)&props,
1300 			 sizeof(struct vmstorage_channel_properties),
1301 			 storvsc_on_channel_callback, device->channel);
1302 
1303 	if (ret != 0)
1304 		return ret;
1305 
1306 	ret = storvsc_channel_init(device);
1307 
1308 	return ret;
1309 }
1310 
1311 static int storvsc_dev_remove(struct hv_device *device)
1312 {
1313 	struct storvsc_device *stor_device;
1314 	unsigned long flags;
1315 
1316 	stor_device = hv_get_drvdata(device);
1317 
1318 	spin_lock_irqsave(&device->channel->inbound_lock, flags);
1319 	stor_device->destroy = true;
1320 	spin_unlock_irqrestore(&device->channel->inbound_lock, flags);
1321 
1322 	/*
1323 	 * At this point, all outbound traffic should be disable. We
1324 	 * only allow inbound traffic (responses) to proceed so that
1325 	 * outstanding requests can be completed.
1326 	 */
1327 
1328 	storvsc_wait_to_drain(stor_device);
1329 
1330 	/*
1331 	 * Since we have already drained, we don't need to busy wait
1332 	 * as was done in final_release_stor_device()
1333 	 * Note that we cannot set the ext pointer to NULL until
1334 	 * we have drained - to drain the outgoing packets, we need to
1335 	 * allow incoming packets.
1336 	 */
1337 	spin_lock_irqsave(&device->channel->inbound_lock, flags);
1338 	hv_set_drvdata(device, NULL);
1339 	spin_unlock_irqrestore(&device->channel->inbound_lock, flags);
1340 
1341 	/* Close the channel */
1342 	vmbus_close(device->channel);
1343 
1344 	kfree(stor_device);
1345 	return 0;
1346 }
1347 
1348 static int storvsc_do_io(struct hv_device *device,
1349 			 struct storvsc_cmd_request *request)
1350 {
1351 	struct storvsc_device *stor_device;
1352 	struct vstor_packet *vstor_packet;
1353 	struct vmbus_channel *outgoing_channel;
1354 	int ret = 0;
1355 
1356 	vstor_packet = &request->vstor_packet;
1357 	stor_device = get_out_stor_device(device);
1358 
1359 	if (!stor_device)
1360 		return -ENODEV;
1361 
1362 
1363 	request->device  = device;
1364 	/*
1365 	 * Select an an appropriate channel to send the request out.
1366 	 */
1367 
1368 	outgoing_channel = vmbus_get_outgoing_channel(device->channel);
1369 
1370 
1371 	vstor_packet->flags |= REQUEST_COMPLETION_FLAG;
1372 
1373 	vstor_packet->vm_srb.length = (sizeof(struct vmscsi_request) -
1374 					vmscsi_size_delta);
1375 
1376 
1377 	vstor_packet->vm_srb.sense_info_length = sense_buffer_size;
1378 
1379 
1380 	vstor_packet->vm_srb.data_transfer_length =
1381 	request->payload->range.len;
1382 
1383 	vstor_packet->operation = VSTOR_OPERATION_EXECUTE_SRB;
1384 
1385 	if (request->payload->range.len) {
1386 
1387 		ret = vmbus_sendpacket_mpb_desc(outgoing_channel,
1388 				request->payload, request->payload_sz,
1389 				vstor_packet,
1390 				(sizeof(struct vstor_packet) -
1391 				vmscsi_size_delta),
1392 				(unsigned long)request);
1393 	} else {
1394 		ret = vmbus_sendpacket(outgoing_channel, vstor_packet,
1395 			       (sizeof(struct vstor_packet) -
1396 				vmscsi_size_delta),
1397 			       (unsigned long)request,
1398 			       VM_PKT_DATA_INBAND,
1399 			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
1400 	}
1401 
1402 	if (ret != 0)
1403 		return ret;
1404 
1405 	atomic_inc(&stor_device->num_outstanding_req);
1406 
1407 	return ret;
1408 }
1409 
1410 static int storvsc_device_configure(struct scsi_device *sdevice)
1411 {
1412 
1413 	blk_queue_max_segment_size(sdevice->request_queue, PAGE_SIZE);
1414 
1415 	blk_queue_bounce_limit(sdevice->request_queue, BLK_BOUNCE_ANY);
1416 
1417 	blk_queue_rq_timeout(sdevice->request_queue, (storvsc_timeout * HZ));
1418 
1419 	sdevice->no_write_same = 1;
1420 
1421 	/*
1422 	 * Add blist flags to permit the reading of the VPD pages even when
1423 	 * the target may claim SPC-2 compliance. MSFT targets currently
1424 	 * claim SPC-2 compliance while they implement post SPC-2 features.
1425 	 * With this patch we can correctly handle WRITE_SAME_16 issues.
1426 	 */
1427 	sdevice->sdev_bflags |= msft_blist_flags;
1428 
1429 	/*
1430 	 * If the host is WIN8 or WIN8 R2, claim conformance to SPC-3
1431 	 * if the device is a MSFT virtual device.
1432 	 */
1433 	if (!strncmp(sdevice->vendor, "Msft", 4)) {
1434 		switch (vmbus_proto_version) {
1435 		case VERSION_WIN8:
1436 		case VERSION_WIN8_1:
1437 			sdevice->scsi_level = SCSI_SPC_3;
1438 			break;
1439 		}
1440 	}
1441 
1442 	return 0;
1443 }
1444 
1445 static int storvsc_get_chs(struct scsi_device *sdev, struct block_device * bdev,
1446 			   sector_t capacity, int *info)
1447 {
1448 	sector_t nsect = capacity;
1449 	sector_t cylinders = nsect;
1450 	int heads, sectors_pt;
1451 
1452 	/*
1453 	 * We are making up these values; let us keep it simple.
1454 	 */
1455 	heads = 0xff;
1456 	sectors_pt = 0x3f;      /* Sectors per track */
1457 	sector_div(cylinders, heads * sectors_pt);
1458 	if ((sector_t)(cylinders + 1) * heads * sectors_pt < nsect)
1459 		cylinders = 0xffff;
1460 
1461 	info[0] = heads;
1462 	info[1] = sectors_pt;
1463 	info[2] = (int)cylinders;
1464 
1465 	return 0;
1466 }
1467 
1468 static int storvsc_host_reset_handler(struct scsi_cmnd *scmnd)
1469 {
1470 	struct hv_host_device *host_dev = shost_priv(scmnd->device->host);
1471 	struct hv_device *device = host_dev->dev;
1472 
1473 	struct storvsc_device *stor_device;
1474 	struct storvsc_cmd_request *request;
1475 	struct vstor_packet *vstor_packet;
1476 	int ret, t;
1477 
1478 
1479 	stor_device = get_out_stor_device(device);
1480 	if (!stor_device)
1481 		return FAILED;
1482 
1483 	request = &stor_device->reset_request;
1484 	vstor_packet = &request->vstor_packet;
1485 
1486 	init_completion(&request->wait_event);
1487 
1488 	vstor_packet->operation = VSTOR_OPERATION_RESET_BUS;
1489 	vstor_packet->flags = REQUEST_COMPLETION_FLAG;
1490 	vstor_packet->vm_srb.path_id = stor_device->path_id;
1491 
1492 	ret = vmbus_sendpacket(device->channel, vstor_packet,
1493 			       (sizeof(struct vstor_packet) -
1494 				vmscsi_size_delta),
1495 			       (unsigned long)&stor_device->reset_request,
1496 			       VM_PKT_DATA_INBAND,
1497 			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
1498 	if (ret != 0)
1499 		return FAILED;
1500 
1501 	t = wait_for_completion_timeout(&request->wait_event, 5*HZ);
1502 	if (t == 0)
1503 		return TIMEOUT_ERROR;
1504 
1505 
1506 	/*
1507 	 * At this point, all outstanding requests in the adapter
1508 	 * should have been flushed out and return to us
1509 	 * There is a potential race here where the host may be in
1510 	 * the process of responding when we return from here.
1511 	 * Just wait for all in-transit packets to be accounted for
1512 	 * before we return from here.
1513 	 */
1514 	storvsc_wait_to_drain(stor_device);
1515 
1516 	return SUCCESS;
1517 }
1518 
1519 /*
1520  * The host guarantees to respond to each command, although I/O latencies might
1521  * be unbounded on Azure.  Reset the timer unconditionally to give the host a
1522  * chance to perform EH.
1523  */
1524 static enum blk_eh_timer_return storvsc_eh_timed_out(struct scsi_cmnd *scmnd)
1525 {
1526 	return BLK_EH_RESET_TIMER;
1527 }
1528 
1529 static bool storvsc_scsi_cmd_ok(struct scsi_cmnd *scmnd)
1530 {
1531 	bool allowed = true;
1532 	u8 scsi_op = scmnd->cmnd[0];
1533 
1534 	switch (scsi_op) {
1535 	/* the host does not handle WRITE_SAME, log accident usage */
1536 	case WRITE_SAME:
1537 	/*
1538 	 * smartd sends this command and the host does not handle
1539 	 * this. So, don't send it.
1540 	 */
1541 	case SET_WINDOW:
1542 		scmnd->result = ILLEGAL_REQUEST << 16;
1543 		allowed = false;
1544 		break;
1545 	default:
1546 		break;
1547 	}
1548 	return allowed;
1549 }
1550 
1551 static int storvsc_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *scmnd)
1552 {
1553 	int ret;
1554 	struct hv_host_device *host_dev = shost_priv(host);
1555 	struct hv_device *dev = host_dev->dev;
1556 	struct storvsc_cmd_request *cmd_request = scsi_cmd_priv(scmnd);
1557 	int i;
1558 	struct scatterlist *sgl;
1559 	unsigned int sg_count = 0;
1560 	struct vmscsi_request *vm_srb;
1561 	struct scatterlist *cur_sgl;
1562 	struct vmbus_packet_mpb_array  *payload;
1563 	u32 payload_sz;
1564 	u32 length;
1565 
1566 	if (vmstor_current_major <= VMSTOR_WIN8_MAJOR) {
1567 		/*
1568 		 * On legacy hosts filter unimplemented commands.
1569 		 * Future hosts are expected to correctly handle
1570 		 * unsupported commands. Furthermore, it is
1571 		 * possible that some of the currently
1572 		 * unsupported commands maybe supported in
1573 		 * future versions of the host.
1574 		 */
1575 		if (!storvsc_scsi_cmd_ok(scmnd)) {
1576 			scmnd->scsi_done(scmnd);
1577 			return 0;
1578 		}
1579 	}
1580 
1581 	/* Setup the cmd request */
1582 	cmd_request->cmd = scmnd;
1583 
1584 	vm_srb = &cmd_request->vstor_packet.vm_srb;
1585 	vm_srb->win8_extension.time_out_value = 60;
1586 
1587 	vm_srb->win8_extension.srb_flags |=
1588 		(SRB_FLAGS_QUEUE_ACTION_ENABLE |
1589 		SRB_FLAGS_DISABLE_SYNCH_TRANSFER);
1590 
1591 	/* Build the SRB */
1592 	switch (scmnd->sc_data_direction) {
1593 	case DMA_TO_DEVICE:
1594 		vm_srb->data_in = WRITE_TYPE;
1595 		vm_srb->win8_extension.srb_flags |= SRB_FLAGS_DATA_OUT;
1596 		break;
1597 	case DMA_FROM_DEVICE:
1598 		vm_srb->data_in = READ_TYPE;
1599 		vm_srb->win8_extension.srb_flags |= SRB_FLAGS_DATA_IN;
1600 		break;
1601 	default:
1602 		vm_srb->data_in = UNKNOWN_TYPE;
1603 		vm_srb->win8_extension.srb_flags |= (SRB_FLAGS_DATA_IN |
1604 						     SRB_FLAGS_DATA_OUT);
1605 		break;
1606 	}
1607 
1608 
1609 	vm_srb->port_number = host_dev->port;
1610 	vm_srb->path_id = scmnd->device->channel;
1611 	vm_srb->target_id = scmnd->device->id;
1612 	vm_srb->lun = scmnd->device->lun;
1613 
1614 	vm_srb->cdb_length = scmnd->cmd_len;
1615 
1616 	memcpy(vm_srb->cdb, scmnd->cmnd, vm_srb->cdb_length);
1617 
1618 	sgl = (struct scatterlist *)scsi_sglist(scmnd);
1619 	sg_count = scsi_sg_count(scmnd);
1620 
1621 	length = scsi_bufflen(scmnd);
1622 	payload = (struct vmbus_packet_mpb_array *)&cmd_request->mpb;
1623 	payload_sz = sizeof(cmd_request->mpb);
1624 
1625 	if (sg_count) {
1626 		/* check if we need to bounce the sgl */
1627 		if (do_bounce_buffer(sgl, scsi_sg_count(scmnd)) != -1) {
1628 			cmd_request->bounce_sgl =
1629 				create_bounce_buffer(sgl, sg_count,
1630 						     length,
1631 						     vm_srb->data_in);
1632 			if (!cmd_request->bounce_sgl)
1633 				return SCSI_MLQUEUE_HOST_BUSY;
1634 
1635 			cmd_request->bounce_sgl_count =
1636 				ALIGN(length, PAGE_SIZE) >> PAGE_SHIFT;
1637 
1638 			if (vm_srb->data_in == WRITE_TYPE)
1639 				copy_to_bounce_buffer(sgl,
1640 					cmd_request->bounce_sgl, sg_count);
1641 
1642 			sgl = cmd_request->bounce_sgl;
1643 			sg_count = cmd_request->bounce_sgl_count;
1644 		}
1645 
1646 
1647 		if (sg_count > MAX_PAGE_BUFFER_COUNT) {
1648 
1649 			payload_sz = (sg_count * sizeof(void *) +
1650 				      sizeof(struct vmbus_packet_mpb_array));
1651 			payload = kmalloc(payload_sz, GFP_ATOMIC);
1652 			if (!payload) {
1653 				if (cmd_request->bounce_sgl_count)
1654 					destroy_bounce_buffer(
1655 					cmd_request->bounce_sgl,
1656 					cmd_request->bounce_sgl_count);
1657 
1658 					return SCSI_MLQUEUE_DEVICE_BUSY;
1659 			}
1660 		}
1661 
1662 		payload->range.len = length;
1663 		payload->range.offset = sgl[0].offset;
1664 
1665 		cur_sgl = sgl;
1666 		for (i = 0; i < sg_count; i++) {
1667 			payload->range.pfn_array[i] =
1668 				page_to_pfn(sg_page((cur_sgl)));
1669 			cur_sgl = sg_next(cur_sgl);
1670 		}
1671 
1672 	} else if (scsi_sglist(scmnd)) {
1673 		payload->range.len = length;
1674 		payload->range.offset =
1675 			virt_to_phys(scsi_sglist(scmnd)) & (PAGE_SIZE-1);
1676 		payload->range.pfn_array[0] =
1677 			virt_to_phys(scsi_sglist(scmnd)) >> PAGE_SHIFT;
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);
1685 
1686 	if (ret == -EAGAIN) {
1687 		/* no more space */
1688 
1689 		if (cmd_request->bounce_sgl_count)
1690 			destroy_bounce_buffer(cmd_request->bounce_sgl,
1691 					cmd_request->bounce_sgl_count);
1692 
1693 		return SCSI_MLQUEUE_DEVICE_BUSY;
1694 	}
1695 
1696 	return 0;
1697 }
1698 
1699 static struct scsi_host_template scsi_driver = {
1700 	.module	=		THIS_MODULE,
1701 	.name =			"storvsc_host_t",
1702 	.cmd_size =             sizeof(struct storvsc_cmd_request),
1703 	.bios_param =		storvsc_get_chs,
1704 	.queuecommand =		storvsc_queuecommand,
1705 	.eh_host_reset_handler =	storvsc_host_reset_handler,
1706 	.proc_name =		"storvsc_host",
1707 	.eh_timed_out =		storvsc_eh_timed_out,
1708 	.slave_configure =	storvsc_device_configure,
1709 	.cmd_per_lun =		255,
1710 	.this_id =		-1,
1711 	.use_clustering =	ENABLE_CLUSTERING,
1712 	/* Make sure we dont get a sg segment crosses a page boundary */
1713 	.dma_boundary =		PAGE_SIZE-1,
1714 	.no_write_same =	1,
1715 };
1716 
1717 enum {
1718 	SCSI_GUID,
1719 	IDE_GUID,
1720 	SFC_GUID,
1721 };
1722 
1723 static const struct hv_vmbus_device_id id_table[] = {
1724 	/* SCSI guid */
1725 	{ HV_SCSI_GUID,
1726 	  .driver_data = SCSI_GUID
1727 	},
1728 	/* IDE guid */
1729 	{ HV_IDE_GUID,
1730 	  .driver_data = IDE_GUID
1731 	},
1732 	/* Fibre Channel GUID */
1733 	{
1734 	  HV_SYNTHFC_GUID,
1735 	  .driver_data = SFC_GUID
1736 	},
1737 	{ },
1738 };
1739 
1740 MODULE_DEVICE_TABLE(vmbus, id_table);
1741 
1742 static int storvsc_probe(struct hv_device *device,
1743 			const struct hv_vmbus_device_id *dev_id)
1744 {
1745 	int ret;
1746 	int num_cpus = num_online_cpus();
1747 	struct Scsi_Host *host;
1748 	struct hv_host_device *host_dev;
1749 	bool dev_is_ide = ((dev_id->driver_data == IDE_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 	switch (vmbus_proto_version) {
1763 	case VERSION_WS2008:
1764 	case VERSION_WIN7:
1765 		sense_buffer_size = PRE_WIN8_STORVSC_SENSE_BUFFER_SIZE;
1766 		vmscsi_size_delta = sizeof(struct vmscsi_win8_extension);
1767 		vmstor_current_major = VMSTOR_WIN7_MAJOR;
1768 		vmstor_current_minor = VMSTOR_WIN7_MINOR;
1769 		max_luns_per_target = STORVSC_IDE_MAX_LUNS_PER_TARGET;
1770 		max_targets = STORVSC_IDE_MAX_TARGETS;
1771 		max_channels = STORVSC_IDE_MAX_CHANNELS;
1772 		break;
1773 	default:
1774 		sense_buffer_size = POST_WIN7_STORVSC_SENSE_BUFFER_SIZE;
1775 		vmscsi_size_delta = 0;
1776 		vmstor_current_major = VMSTOR_WIN8_MAJOR;
1777 		vmstor_current_minor = VMSTOR_WIN8_MINOR;
1778 		max_luns_per_target = STORVSC_MAX_LUNS_PER_TARGET;
1779 		max_targets = STORVSC_MAX_TARGETS;
1780 		max_channels = STORVSC_MAX_CHANNELS;
1781 		/*
1782 		 * On Windows8 and above, we support sub-channels for storage.
1783 		 * The number of sub-channels offerred is based on the number of
1784 		 * VCPUs in the guest.
1785 		 */
1786 		max_sub_channels = (num_cpus / storvsc_vcpus_per_sub_channel);
1787 		break;
1788 	}
1789 
1790 	scsi_driver.can_queue = (max_outstanding_req_per_channel *
1791 				 (max_sub_channels + 1));
1792 
1793 	host = scsi_host_alloc(&scsi_driver,
1794 			       sizeof(struct hv_host_device));
1795 	if (!host)
1796 		return -ENOMEM;
1797 
1798 	host_dev = shost_priv(host);
1799 	memset(host_dev, 0, sizeof(struct hv_host_device));
1800 
1801 	host_dev->port = host->host_no;
1802 	host_dev->dev = device;
1803 
1804 
1805 	stor_device = kzalloc(sizeof(struct storvsc_device), GFP_KERNEL);
1806 	if (!stor_device) {
1807 		ret = -ENOMEM;
1808 		goto err_out0;
1809 	}
1810 
1811 	stor_device->destroy = false;
1812 	stor_device->open_sub_channel = false;
1813 	init_waitqueue_head(&stor_device->waiting_to_drain);
1814 	stor_device->device = device;
1815 	stor_device->host = host;
1816 	hv_set_drvdata(device, stor_device);
1817 
1818 	stor_device->port_number = host->host_no;
1819 	ret = storvsc_connect_to_vsp(device, storvsc_ringbuffer_size);
1820 	if (ret)
1821 		goto err_out1;
1822 
1823 	host_dev->path = stor_device->path_id;
1824 	host_dev->target = stor_device->target_id;
1825 
1826 	switch (dev_id->driver_data) {
1827 	case SFC_GUID:
1828 		host->max_lun = STORVSC_FC_MAX_LUNS_PER_TARGET;
1829 		host->max_id = STORVSC_FC_MAX_TARGETS;
1830 		host->max_channel = STORVSC_FC_MAX_CHANNELS - 1;
1831 		break;
1832 
1833 	case SCSI_GUID:
1834 		host->max_lun = max_luns_per_target;
1835 		host->max_id = max_targets;
1836 		host->max_channel = max_channels - 1;
1837 		break;
1838 
1839 	default:
1840 		host->max_lun = STORVSC_IDE_MAX_LUNS_PER_TARGET;
1841 		host->max_id = STORVSC_IDE_MAX_TARGETS;
1842 		host->max_channel = STORVSC_IDE_MAX_CHANNELS - 1;
1843 		break;
1844 	}
1845 	/* max cmd length */
1846 	host->max_cmd_len = STORVSC_MAX_CMD_LEN;
1847 
1848 	/*
1849 	 * set the table size based on the info we got
1850 	 * from the host.
1851 	 */
1852 	host->sg_tablesize = (stor_device->max_transfer_bytes >> PAGE_SHIFT);
1853 
1854 	/* Register the HBA and start the scsi bus scan */
1855 	ret = scsi_add_host(host, &device->device);
1856 	if (ret != 0)
1857 		goto err_out2;
1858 
1859 	if (!dev_is_ide) {
1860 		scsi_scan_host(host);
1861 	} else {
1862 		target = (device->dev_instance.b[5] << 8 |
1863 			 device->dev_instance.b[4]);
1864 		ret = scsi_add_device(host, 0, target, 0);
1865 		if (ret) {
1866 			scsi_remove_host(host);
1867 			goto err_out2;
1868 		}
1869 	}
1870 	return 0;
1871 
1872 err_out2:
1873 	/*
1874 	 * Once we have connected with the host, we would need to
1875 	 * to invoke storvsc_dev_remove() to rollback this state and
1876 	 * this call also frees up the stor_device; hence the jump around
1877 	 * err_out1 label.
1878 	 */
1879 	storvsc_dev_remove(device);
1880 	goto err_out0;
1881 
1882 err_out1:
1883 	kfree(stor_device);
1884 
1885 err_out0:
1886 	scsi_host_put(host);
1887 	return ret;
1888 }
1889 
1890 static int storvsc_remove(struct hv_device *dev)
1891 {
1892 	struct storvsc_device *stor_device = hv_get_drvdata(dev);
1893 	struct Scsi_Host *host = stor_device->host;
1894 
1895 	scsi_remove_host(host);
1896 	storvsc_dev_remove(dev);
1897 	scsi_host_put(host);
1898 
1899 	return 0;
1900 }
1901 
1902 static struct hv_driver storvsc_drv = {
1903 	.name = KBUILD_MODNAME,
1904 	.id_table = id_table,
1905 	.probe = storvsc_probe,
1906 	.remove = storvsc_remove,
1907 };
1908 
1909 static int __init storvsc_drv_init(void)
1910 {
1911 
1912 	/*
1913 	 * Divide the ring buffer data size (which is 1 page less
1914 	 * than the ring buffer size since that page is reserved for
1915 	 * the ring buffer indices) by the max request size (which is
1916 	 * vmbus_channel_packet_multipage_buffer + struct vstor_packet + u64)
1917 	 */
1918 	max_outstanding_req_per_channel =
1919 		((storvsc_ringbuffer_size - PAGE_SIZE) /
1920 		ALIGN(MAX_MULTIPAGE_BUFFER_PACKET +
1921 		sizeof(struct vstor_packet) + sizeof(u64) -
1922 		vmscsi_size_delta,
1923 		sizeof(u64)));
1924 
1925 	return vmbus_driver_register(&storvsc_drv);
1926 }
1927 
1928 static void __exit storvsc_drv_exit(void)
1929 {
1930 	vmbus_driver_unregister(&storvsc_drv);
1931 }
1932 
1933 MODULE_LICENSE("GPL");
1934 MODULE_DESCRIPTION("Microsoft Hyper-V virtual storage driver");
1935 module_init(storvsc_drv_init);
1936 module_exit(storvsc_drv_exit);
1937