xref: /openbmc/linux/drivers/scsi/storvsc_drv.c (revision 7b6d864b)
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/mempool.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 
312 /*
313  * We setup a mempool to allocate request structures for this driver
314  * on a per-lun basis. The following define specifies the number of
315  * elements in the pool.
316  */
317 
318 #define STORVSC_MIN_BUF_NR				64
319 static int storvsc_ringbuffer_size = (20 * PAGE_SIZE);
320 
321 module_param(storvsc_ringbuffer_size, int, S_IRUGO);
322 MODULE_PARM_DESC(storvsc_ringbuffer_size, "Ring buffer size (bytes)");
323 
324 /*
325  * Timeout in seconds for all devices managed by this driver.
326  */
327 static int storvsc_timeout = 180;
328 
329 #define STORVSC_MAX_IO_REQUESTS				128
330 
331 /*
332  * In Hyper-V, each port/path/target maps to 1 scsi host adapter.  In
333  * reality, the path/target is not used (ie always set to 0) so our
334  * scsi host adapter essentially has 1 bus with 1 target that contains
335  * up to 256 luns.
336  */
337 #define STORVSC_MAX_LUNS_PER_TARGET			64
338 #define STORVSC_MAX_TARGETS				1
339 #define STORVSC_MAX_CHANNELS				1
340 
341 
342 
343 struct storvsc_cmd_request {
344 	struct list_head entry;
345 	struct scsi_cmnd *cmd;
346 
347 	unsigned int bounce_sgl_count;
348 	struct scatterlist *bounce_sgl;
349 
350 	struct hv_device *device;
351 
352 	/* Synchronize the request/response if needed */
353 	struct completion wait_event;
354 
355 	unsigned char *sense_buffer;
356 	struct hv_multipage_buffer data_buffer;
357 	struct vstor_packet vstor_packet;
358 };
359 
360 
361 /* A storvsc device is a device object that contains a vmbus channel */
362 struct storvsc_device {
363 	struct hv_device *device;
364 
365 	bool	 destroy;
366 	bool	 drain_notify;
367 	atomic_t num_outstanding_req;
368 	struct Scsi_Host *host;
369 
370 	wait_queue_head_t waiting_to_drain;
371 
372 	/*
373 	 * Each unique Port/Path/Target represents 1 channel ie scsi
374 	 * controller. In reality, the pathid, targetid is always 0
375 	 * and the port is set by us
376 	 */
377 	unsigned int port_number;
378 	unsigned char path_id;
379 	unsigned char target_id;
380 
381 	/* Used for vsc/vsp channel reset process */
382 	struct storvsc_cmd_request init_request;
383 	struct storvsc_cmd_request reset_request;
384 };
385 
386 struct stor_mem_pools {
387 	struct kmem_cache *request_pool;
388 	mempool_t *request_mempool;
389 };
390 
391 struct hv_host_device {
392 	struct hv_device *dev;
393 	unsigned int port;
394 	unsigned char path;
395 	unsigned char target;
396 };
397 
398 struct storvsc_scan_work {
399 	struct work_struct work;
400 	struct Scsi_Host *host;
401 	uint lun;
402 };
403 
404 static void storvsc_device_scan(struct work_struct *work)
405 {
406 	struct storvsc_scan_work *wrk;
407 	uint lun;
408 	struct scsi_device *sdev;
409 
410 	wrk = container_of(work, struct storvsc_scan_work, work);
411 	lun = wrk->lun;
412 
413 	sdev = scsi_device_lookup(wrk->host, 0, 0, lun);
414 	if (!sdev)
415 		goto done;
416 	scsi_rescan_device(&sdev->sdev_gendev);
417 	scsi_device_put(sdev);
418 
419 done:
420 	kfree(wrk);
421 }
422 
423 static void storvsc_bus_scan(struct work_struct *work)
424 {
425 	struct storvsc_scan_work *wrk;
426 	int id, order_id;
427 
428 	wrk = container_of(work, struct storvsc_scan_work, work);
429 	for (id = 0; id < wrk->host->max_id; ++id) {
430 		if (wrk->host->reverse_ordering)
431 			order_id = wrk->host->max_id - id - 1;
432 		else
433 			order_id = id;
434 
435 		scsi_scan_target(&wrk->host->shost_gendev, 0,
436 				order_id, SCAN_WILD_CARD, 1);
437 	}
438 	kfree(wrk);
439 }
440 
441 static void storvsc_remove_lun(struct work_struct *work)
442 {
443 	struct storvsc_scan_work *wrk;
444 	struct scsi_device *sdev;
445 
446 	wrk = container_of(work, struct storvsc_scan_work, work);
447 	if (!scsi_host_get(wrk->host))
448 		goto done;
449 
450 	sdev = scsi_device_lookup(wrk->host, 0, 0, wrk->lun);
451 
452 	if (sdev) {
453 		scsi_remove_device(sdev);
454 		scsi_device_put(sdev);
455 	}
456 	scsi_host_put(wrk->host);
457 
458 done:
459 	kfree(wrk);
460 }
461 
462 /*
463  * Major/minor macros.  Minor version is in LSB, meaning that earlier flat
464  * version numbers will be interpreted as "0.x" (i.e., 1 becomes 0.1).
465  */
466 
467 static inline u16 storvsc_get_version(u8 major, u8 minor)
468 {
469 	u16 version;
470 
471 	version = ((major << 8) | minor);
472 	return version;
473 }
474 
475 /*
476  * We can get incoming messages from the host that are not in response to
477  * messages that we have sent out. An example of this would be messages
478  * received by the guest to notify dynamic addition/removal of LUNs. To
479  * deal with potential race conditions where the driver may be in the
480  * midst of being unloaded when we might receive an unsolicited message
481  * from the host, we have implemented a mechanism to gurantee sequential
482  * consistency:
483  *
484  * 1) Once the device is marked as being destroyed, we will fail all
485  *    outgoing messages.
486  * 2) We permit incoming messages when the device is being destroyed,
487  *    only to properly account for messages already sent out.
488  */
489 
490 static inline struct storvsc_device *get_out_stor_device(
491 					struct hv_device *device)
492 {
493 	struct storvsc_device *stor_device;
494 
495 	stor_device = hv_get_drvdata(device);
496 
497 	if (stor_device && stor_device->destroy)
498 		stor_device = NULL;
499 
500 	return stor_device;
501 }
502 
503 
504 static inline void storvsc_wait_to_drain(struct storvsc_device *dev)
505 {
506 	dev->drain_notify = true;
507 	wait_event(dev->waiting_to_drain,
508 		   atomic_read(&dev->num_outstanding_req) == 0);
509 	dev->drain_notify = false;
510 }
511 
512 static inline struct storvsc_device *get_in_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)
520 		goto get_in_err;
521 
522 	/*
523 	 * If the device is being destroyed; allow incoming
524 	 * traffic only to cleanup outstanding requests.
525 	 */
526 
527 	if (stor_device->destroy  &&
528 		(atomic_read(&stor_device->num_outstanding_req) == 0))
529 		stor_device = NULL;
530 
531 get_in_err:
532 	return stor_device;
533 
534 }
535 
536 static void destroy_bounce_buffer(struct scatterlist *sgl,
537 				  unsigned int sg_count)
538 {
539 	int i;
540 	struct page *page_buf;
541 
542 	for (i = 0; i < sg_count; i++) {
543 		page_buf = sg_page((&sgl[i]));
544 		if (page_buf != NULL)
545 			__free_page(page_buf);
546 	}
547 
548 	kfree(sgl);
549 }
550 
551 static int do_bounce_buffer(struct scatterlist *sgl, unsigned int sg_count)
552 {
553 	int i;
554 
555 	/* No need to check */
556 	if (sg_count < 2)
557 		return -1;
558 
559 	/* We have at least 2 sg entries */
560 	for (i = 0; i < sg_count; i++) {
561 		if (i == 0) {
562 			/* make sure 1st one does not have hole */
563 			if (sgl[i].offset + sgl[i].length != PAGE_SIZE)
564 				return i;
565 		} else if (i == sg_count - 1) {
566 			/* make sure last one does not have hole */
567 			if (sgl[i].offset != 0)
568 				return i;
569 		} else {
570 			/* make sure no hole in the middle */
571 			if (sgl[i].length != PAGE_SIZE || sgl[i].offset != 0)
572 				return i;
573 		}
574 	}
575 	return -1;
576 }
577 
578 static struct scatterlist *create_bounce_buffer(struct scatterlist *sgl,
579 						unsigned int sg_count,
580 						unsigned int len,
581 						int write)
582 {
583 	int i;
584 	int num_pages;
585 	struct scatterlist *bounce_sgl;
586 	struct page *page_buf;
587 	unsigned int buf_len = ((write == WRITE_TYPE) ? 0 : PAGE_SIZE);
588 
589 	num_pages = ALIGN(len, PAGE_SIZE) >> PAGE_SHIFT;
590 
591 	bounce_sgl = kcalloc(num_pages, sizeof(struct scatterlist), GFP_ATOMIC);
592 	if (!bounce_sgl)
593 		return NULL;
594 
595 	sg_init_table(bounce_sgl, num_pages);
596 	for (i = 0; i < num_pages; i++) {
597 		page_buf = alloc_page(GFP_ATOMIC);
598 		if (!page_buf)
599 			goto cleanup;
600 		sg_set_page(&bounce_sgl[i], page_buf, buf_len, 0);
601 	}
602 
603 	return bounce_sgl;
604 
605 cleanup:
606 	destroy_bounce_buffer(bounce_sgl, num_pages);
607 	return NULL;
608 }
609 
610 /* Disgusting wrapper functions */
611 static inline unsigned long sg_kmap_atomic(struct scatterlist *sgl, int idx)
612 {
613 	void *addr = kmap_atomic(sg_page(sgl + idx));
614 	return (unsigned long)addr;
615 }
616 
617 static inline void sg_kunmap_atomic(unsigned long addr)
618 {
619 	kunmap_atomic((void *)addr);
620 }
621 
622 
623 /* Assume the original sgl has enough room */
624 static unsigned int copy_from_bounce_buffer(struct scatterlist *orig_sgl,
625 					    struct scatterlist *bounce_sgl,
626 					    unsigned int orig_sgl_count,
627 					    unsigned int bounce_sgl_count)
628 {
629 	int i;
630 	int j = 0;
631 	unsigned long src, dest;
632 	unsigned int srclen, destlen, copylen;
633 	unsigned int total_copied = 0;
634 	unsigned long bounce_addr = 0;
635 	unsigned long dest_addr = 0;
636 	unsigned long flags;
637 
638 	local_irq_save(flags);
639 
640 	for (i = 0; i < orig_sgl_count; i++) {
641 		dest_addr = sg_kmap_atomic(orig_sgl,i) + orig_sgl[i].offset;
642 		dest = dest_addr;
643 		destlen = orig_sgl[i].length;
644 
645 		if (bounce_addr == 0)
646 			bounce_addr = sg_kmap_atomic(bounce_sgl,j);
647 
648 		while (destlen) {
649 			src = bounce_addr + bounce_sgl[j].offset;
650 			srclen = bounce_sgl[j].length - bounce_sgl[j].offset;
651 
652 			copylen = min(srclen, destlen);
653 			memcpy((void *)dest, (void *)src, copylen);
654 
655 			total_copied += copylen;
656 			bounce_sgl[j].offset += copylen;
657 			destlen -= copylen;
658 			dest += copylen;
659 
660 			if (bounce_sgl[j].offset == bounce_sgl[j].length) {
661 				/* full */
662 				sg_kunmap_atomic(bounce_addr);
663 				j++;
664 
665 				/*
666 				 * It is possible that the number of elements
667 				 * in the bounce buffer may not be equal to
668 				 * the number of elements in the original
669 				 * scatter list. Handle this correctly.
670 				 */
671 
672 				if (j == bounce_sgl_count) {
673 					/*
674 					 * We are done; cleanup and return.
675 					 */
676 					sg_kunmap_atomic(dest_addr - orig_sgl[i].offset);
677 					local_irq_restore(flags);
678 					return total_copied;
679 				}
680 
681 				/* if we need to use another bounce buffer */
682 				if (destlen || i != orig_sgl_count - 1)
683 					bounce_addr = sg_kmap_atomic(bounce_sgl,j);
684 			} else if (destlen == 0 && i == orig_sgl_count - 1) {
685 				/* unmap the last bounce that is < PAGE_SIZE */
686 				sg_kunmap_atomic(bounce_addr);
687 			}
688 		}
689 
690 		sg_kunmap_atomic(dest_addr - orig_sgl[i].offset);
691 	}
692 
693 	local_irq_restore(flags);
694 
695 	return total_copied;
696 }
697 
698 /* Assume the bounce_sgl has enough room ie using the create_bounce_buffer() */
699 static unsigned int copy_to_bounce_buffer(struct scatterlist *orig_sgl,
700 					  struct scatterlist *bounce_sgl,
701 					  unsigned int orig_sgl_count)
702 {
703 	int i;
704 	int j = 0;
705 	unsigned long src, dest;
706 	unsigned int srclen, destlen, copylen;
707 	unsigned int total_copied = 0;
708 	unsigned long bounce_addr = 0;
709 	unsigned long src_addr = 0;
710 	unsigned long flags;
711 
712 	local_irq_save(flags);
713 
714 	for (i = 0; i < orig_sgl_count; i++) {
715 		src_addr = sg_kmap_atomic(orig_sgl,i) + orig_sgl[i].offset;
716 		src = src_addr;
717 		srclen = orig_sgl[i].length;
718 
719 		if (bounce_addr == 0)
720 			bounce_addr = sg_kmap_atomic(bounce_sgl,j);
721 
722 		while (srclen) {
723 			/* assume bounce offset always == 0 */
724 			dest = bounce_addr + bounce_sgl[j].length;
725 			destlen = PAGE_SIZE - bounce_sgl[j].length;
726 
727 			copylen = min(srclen, destlen);
728 			memcpy((void *)dest, (void *)src, copylen);
729 
730 			total_copied += copylen;
731 			bounce_sgl[j].length += copylen;
732 			srclen -= copylen;
733 			src += copylen;
734 
735 			if (bounce_sgl[j].length == PAGE_SIZE) {
736 				/* full..move to next entry */
737 				sg_kunmap_atomic(bounce_addr);
738 				j++;
739 
740 				/* if we need to use another bounce buffer */
741 				if (srclen || i != orig_sgl_count - 1)
742 					bounce_addr = sg_kmap_atomic(bounce_sgl,j);
743 
744 			} else if (srclen == 0 && i == orig_sgl_count - 1) {
745 				/* unmap the last bounce that is < PAGE_SIZE */
746 				sg_kunmap_atomic(bounce_addr);
747 			}
748 		}
749 
750 		sg_kunmap_atomic(src_addr - orig_sgl[i].offset);
751 	}
752 
753 	local_irq_restore(flags);
754 
755 	return total_copied;
756 }
757 
758 static int storvsc_channel_init(struct hv_device *device)
759 {
760 	struct storvsc_device *stor_device;
761 	struct storvsc_cmd_request *request;
762 	struct vstor_packet *vstor_packet;
763 	int ret, t;
764 
765 	stor_device = get_out_stor_device(device);
766 	if (!stor_device)
767 		return -ENODEV;
768 
769 	request = &stor_device->init_request;
770 	vstor_packet = &request->vstor_packet;
771 
772 	/*
773 	 * Now, initiate the vsc/vsp initialization protocol on the open
774 	 * channel
775 	 */
776 	memset(request, 0, sizeof(struct storvsc_cmd_request));
777 	init_completion(&request->wait_event);
778 	vstor_packet->operation = VSTOR_OPERATION_BEGIN_INITIALIZATION;
779 	vstor_packet->flags = REQUEST_COMPLETION_FLAG;
780 
781 	ret = vmbus_sendpacket(device->channel, vstor_packet,
782 			       (sizeof(struct vstor_packet) -
783 			       vmscsi_size_delta),
784 			       (unsigned long)request,
785 			       VM_PKT_DATA_INBAND,
786 			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
787 	if (ret != 0)
788 		goto cleanup;
789 
790 	t = wait_for_completion_timeout(&request->wait_event, 5*HZ);
791 	if (t == 0) {
792 		ret = -ETIMEDOUT;
793 		goto cleanup;
794 	}
795 
796 	if (vstor_packet->operation != VSTOR_OPERATION_COMPLETE_IO ||
797 	    vstor_packet->status != 0)
798 		goto cleanup;
799 
800 
801 	/* reuse the packet for version range supported */
802 	memset(vstor_packet, 0, sizeof(struct vstor_packet));
803 	vstor_packet->operation = VSTOR_OPERATION_QUERY_PROTOCOL_VERSION;
804 	vstor_packet->flags = REQUEST_COMPLETION_FLAG;
805 
806 	vstor_packet->version.major_minor =
807 		storvsc_get_version(vmstor_current_major, vmstor_current_minor);
808 
809 	/*
810 	 * The revision number is only used in Windows; set it to 0.
811 	 */
812 	vstor_packet->version.revision = 0;
813 
814 	ret = vmbus_sendpacket(device->channel, vstor_packet,
815 			       (sizeof(struct vstor_packet) -
816 				vmscsi_size_delta),
817 			       (unsigned long)request,
818 			       VM_PKT_DATA_INBAND,
819 			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
820 	if (ret != 0)
821 		goto cleanup;
822 
823 	t = wait_for_completion_timeout(&request->wait_event, 5*HZ);
824 	if (t == 0) {
825 		ret = -ETIMEDOUT;
826 		goto cleanup;
827 	}
828 
829 	if (vstor_packet->operation != VSTOR_OPERATION_COMPLETE_IO ||
830 	    vstor_packet->status != 0)
831 		goto cleanup;
832 
833 
834 	memset(vstor_packet, 0, sizeof(struct vstor_packet));
835 	vstor_packet->operation = VSTOR_OPERATION_QUERY_PROPERTIES;
836 	vstor_packet->flags = REQUEST_COMPLETION_FLAG;
837 
838 	ret = vmbus_sendpacket(device->channel, vstor_packet,
839 			       (sizeof(struct vstor_packet) -
840 				vmscsi_size_delta),
841 			       (unsigned long)request,
842 			       VM_PKT_DATA_INBAND,
843 			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
844 
845 	if (ret != 0)
846 		goto cleanup;
847 
848 	t = wait_for_completion_timeout(&request->wait_event, 5*HZ);
849 	if (t == 0) {
850 		ret = -ETIMEDOUT;
851 		goto cleanup;
852 	}
853 
854 	if (vstor_packet->operation != VSTOR_OPERATION_COMPLETE_IO ||
855 	    vstor_packet->status != 0)
856 		goto cleanup;
857 
858 	memset(vstor_packet, 0, sizeof(struct vstor_packet));
859 	vstor_packet->operation = VSTOR_OPERATION_END_INITIALIZATION;
860 	vstor_packet->flags = REQUEST_COMPLETION_FLAG;
861 
862 	ret = vmbus_sendpacket(device->channel, vstor_packet,
863 			       (sizeof(struct vstor_packet) -
864 				vmscsi_size_delta),
865 			       (unsigned long)request,
866 			       VM_PKT_DATA_INBAND,
867 			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
868 
869 	if (ret != 0)
870 		goto cleanup;
871 
872 	t = wait_for_completion_timeout(&request->wait_event, 5*HZ);
873 	if (t == 0) {
874 		ret = -ETIMEDOUT;
875 		goto cleanup;
876 	}
877 
878 	if (vstor_packet->operation != VSTOR_OPERATION_COMPLETE_IO ||
879 	    vstor_packet->status != 0)
880 		goto cleanup;
881 
882 
883 cleanup:
884 	return ret;
885 }
886 
887 static void storvsc_handle_error(struct vmscsi_request *vm_srb,
888 				struct scsi_cmnd *scmnd,
889 				struct Scsi_Host *host,
890 				u8 asc, u8 ascq)
891 {
892 	struct storvsc_scan_work *wrk;
893 	void (*process_err_fn)(struct work_struct *work);
894 	bool do_work = false;
895 
896 	switch (vm_srb->srb_status) {
897 	case SRB_STATUS_ERROR:
898 		/*
899 		 * If there is an error; offline the device since all
900 		 * error recovery strategies would have already been
901 		 * deployed on the host side. However, if the command
902 		 * were a pass-through command deal with it appropriately.
903 		 */
904 		switch (scmnd->cmnd[0]) {
905 		case ATA_16:
906 		case ATA_12:
907 			set_host_byte(scmnd, DID_PASSTHROUGH);
908 			break;
909 		default:
910 			set_host_byte(scmnd, DID_TARGET_FAILURE);
911 		}
912 		break;
913 	case SRB_STATUS_INVALID_LUN:
914 		do_work = true;
915 		process_err_fn = storvsc_remove_lun;
916 		break;
917 	case (SRB_STATUS_ABORTED | SRB_STATUS_AUTOSENSE_VALID):
918 		if ((asc == 0x2a) && (ascq == 0x9)) {
919 			do_work = true;
920 			process_err_fn = storvsc_device_scan;
921 			/*
922 			 * Retry the I/O that trigerred this.
923 			 */
924 			set_host_byte(scmnd, DID_REQUEUE);
925 		}
926 		break;
927 	}
928 
929 	if (!do_work)
930 		return;
931 
932 	/*
933 	 * We need to schedule work to process this error; schedule it.
934 	 */
935 	wrk = kmalloc(sizeof(struct storvsc_scan_work), GFP_ATOMIC);
936 	if (!wrk) {
937 		set_host_byte(scmnd, DID_TARGET_FAILURE);
938 		return;
939 	}
940 
941 	wrk->host = host;
942 	wrk->lun = vm_srb->lun;
943 	INIT_WORK(&wrk->work, process_err_fn);
944 	schedule_work(&wrk->work);
945 }
946 
947 
948 static void storvsc_command_completion(struct storvsc_cmd_request *cmd_request)
949 {
950 	struct scsi_cmnd *scmnd = cmd_request->cmd;
951 	struct hv_host_device *host_dev = shost_priv(scmnd->device->host);
952 	void (*scsi_done_fn)(struct scsi_cmnd *);
953 	struct scsi_sense_hdr sense_hdr;
954 	struct vmscsi_request *vm_srb;
955 	struct stor_mem_pools *memp = scmnd->device->hostdata;
956 	struct Scsi_Host *host;
957 	struct storvsc_device *stor_dev;
958 	struct hv_device *dev = host_dev->dev;
959 
960 	stor_dev = get_in_stor_device(dev);
961 	host = stor_dev->host;
962 
963 	vm_srb = &cmd_request->vstor_packet.vm_srb;
964 	if (cmd_request->bounce_sgl_count) {
965 		if (vm_srb->data_in == READ_TYPE)
966 			copy_from_bounce_buffer(scsi_sglist(scmnd),
967 					cmd_request->bounce_sgl,
968 					scsi_sg_count(scmnd),
969 					cmd_request->bounce_sgl_count);
970 		destroy_bounce_buffer(cmd_request->bounce_sgl,
971 					cmd_request->bounce_sgl_count);
972 	}
973 
974 	scmnd->result = vm_srb->scsi_status;
975 
976 	if (scmnd->result) {
977 		if (scsi_normalize_sense(scmnd->sense_buffer,
978 				SCSI_SENSE_BUFFERSIZE, &sense_hdr))
979 			scsi_print_sense_hdr("storvsc", &sense_hdr);
980 	}
981 
982 	if (vm_srb->srb_status != SRB_STATUS_SUCCESS)
983 		storvsc_handle_error(vm_srb, scmnd, host, sense_hdr.asc,
984 					 sense_hdr.ascq);
985 
986 	scsi_set_resid(scmnd,
987 		cmd_request->data_buffer.len -
988 		vm_srb->data_transfer_length);
989 
990 	scsi_done_fn = scmnd->scsi_done;
991 
992 	scmnd->host_scribble = NULL;
993 	scmnd->scsi_done = NULL;
994 
995 	scsi_done_fn(scmnd);
996 
997 	mempool_free(cmd_request, memp->request_mempool);
998 }
999 
1000 static void storvsc_on_io_completion(struct hv_device *device,
1001 				  struct vstor_packet *vstor_packet,
1002 				  struct storvsc_cmd_request *request)
1003 {
1004 	struct storvsc_device *stor_device;
1005 	struct vstor_packet *stor_pkt;
1006 
1007 	stor_device = hv_get_drvdata(device);
1008 	stor_pkt = &request->vstor_packet;
1009 
1010 	/*
1011 	 * The current SCSI handling on the host side does
1012 	 * not correctly handle:
1013 	 * INQUIRY command with page code parameter set to 0x80
1014 	 * MODE_SENSE command with cmd[2] == 0x1c
1015 	 *
1016 	 * Setup srb and scsi status so this won't be fatal.
1017 	 * We do this so we can distinguish truly fatal failues
1018 	 * (srb status == 0x4) and off-line the device in that case.
1019 	 */
1020 
1021 	if ((stor_pkt->vm_srb.cdb[0] == INQUIRY) ||
1022 	   (stor_pkt->vm_srb.cdb[0] == MODE_SENSE)) {
1023 		vstor_packet->vm_srb.scsi_status = 0;
1024 		vstor_packet->vm_srb.srb_status = SRB_STATUS_SUCCESS;
1025 	}
1026 
1027 
1028 	/* Copy over the status...etc */
1029 	stor_pkt->vm_srb.scsi_status = vstor_packet->vm_srb.scsi_status;
1030 	stor_pkt->vm_srb.srb_status = vstor_packet->vm_srb.srb_status;
1031 	stor_pkt->vm_srb.sense_info_length =
1032 	vstor_packet->vm_srb.sense_info_length;
1033 
1034 	if (vstor_packet->vm_srb.scsi_status != 0 ||
1035 		vstor_packet->vm_srb.srb_status != SRB_STATUS_SUCCESS){
1036 		dev_warn(&device->device,
1037 			 "cmd 0x%x scsi status 0x%x srb status 0x%x\n",
1038 			 stor_pkt->vm_srb.cdb[0],
1039 			 vstor_packet->vm_srb.scsi_status,
1040 			 vstor_packet->vm_srb.srb_status);
1041 	}
1042 
1043 	if ((vstor_packet->vm_srb.scsi_status & 0xFF) == 0x02) {
1044 		/* CHECK_CONDITION */
1045 		if (vstor_packet->vm_srb.srb_status &
1046 			SRB_STATUS_AUTOSENSE_VALID) {
1047 			/* autosense data available */
1048 			dev_warn(&device->device,
1049 				 "stor pkt %p autosense data valid - len %d\n",
1050 				 request,
1051 				 vstor_packet->vm_srb.sense_info_length);
1052 
1053 			memcpy(request->sense_buffer,
1054 			       vstor_packet->vm_srb.sense_data,
1055 			       vstor_packet->vm_srb.sense_info_length);
1056 
1057 		}
1058 	}
1059 
1060 	stor_pkt->vm_srb.data_transfer_length =
1061 	vstor_packet->vm_srb.data_transfer_length;
1062 
1063 	storvsc_command_completion(request);
1064 
1065 	if (atomic_dec_and_test(&stor_device->num_outstanding_req) &&
1066 		stor_device->drain_notify)
1067 		wake_up(&stor_device->waiting_to_drain);
1068 
1069 
1070 }
1071 
1072 static void storvsc_on_receive(struct hv_device *device,
1073 			     struct vstor_packet *vstor_packet,
1074 			     struct storvsc_cmd_request *request)
1075 {
1076 	struct storvsc_scan_work *work;
1077 	struct storvsc_device *stor_device;
1078 
1079 	switch (vstor_packet->operation) {
1080 	case VSTOR_OPERATION_COMPLETE_IO:
1081 		storvsc_on_io_completion(device, vstor_packet, request);
1082 		break;
1083 
1084 	case VSTOR_OPERATION_REMOVE_DEVICE:
1085 	case VSTOR_OPERATION_ENUMERATE_BUS:
1086 		stor_device = get_in_stor_device(device);
1087 		work = kmalloc(sizeof(struct storvsc_scan_work), GFP_ATOMIC);
1088 		if (!work)
1089 			return;
1090 
1091 		INIT_WORK(&work->work, storvsc_bus_scan);
1092 		work->host = stor_device->host;
1093 		schedule_work(&work->work);
1094 		break;
1095 
1096 	default:
1097 		break;
1098 	}
1099 }
1100 
1101 static void storvsc_on_channel_callback(void *context)
1102 {
1103 	struct hv_device *device = (struct hv_device *)context;
1104 	struct storvsc_device *stor_device;
1105 	u32 bytes_recvd;
1106 	u64 request_id;
1107 	unsigned char packet[ALIGN(sizeof(struct vstor_packet), 8)];
1108 	struct storvsc_cmd_request *request;
1109 	int ret;
1110 
1111 
1112 	stor_device = get_in_stor_device(device);
1113 	if (!stor_device)
1114 		return;
1115 
1116 	do {
1117 		ret = vmbus_recvpacket(device->channel, packet,
1118 				       ALIGN((sizeof(struct vstor_packet) -
1119 					     vmscsi_size_delta), 8),
1120 				       &bytes_recvd, &request_id);
1121 		if (ret == 0 && bytes_recvd > 0) {
1122 
1123 			request = (struct storvsc_cmd_request *)
1124 					(unsigned long)request_id;
1125 
1126 			if ((request == &stor_device->init_request) ||
1127 			    (request == &stor_device->reset_request)) {
1128 
1129 				memcpy(&request->vstor_packet, packet,
1130 				       (sizeof(struct vstor_packet) -
1131 					vmscsi_size_delta));
1132 				complete(&request->wait_event);
1133 			} else {
1134 				storvsc_on_receive(device,
1135 						(struct vstor_packet *)packet,
1136 						request);
1137 			}
1138 		} else {
1139 			break;
1140 		}
1141 	} while (1);
1142 
1143 	return;
1144 }
1145 
1146 static int storvsc_connect_to_vsp(struct hv_device *device, u32 ring_size)
1147 {
1148 	struct vmstorage_channel_properties props;
1149 	int ret;
1150 
1151 	memset(&props, 0, sizeof(struct vmstorage_channel_properties));
1152 
1153 	ret = vmbus_open(device->channel,
1154 			 ring_size,
1155 			 ring_size,
1156 			 (void *)&props,
1157 			 sizeof(struct vmstorage_channel_properties),
1158 			 storvsc_on_channel_callback, device);
1159 
1160 	if (ret != 0)
1161 		return ret;
1162 
1163 	ret = storvsc_channel_init(device);
1164 
1165 	return ret;
1166 }
1167 
1168 static int storvsc_dev_remove(struct hv_device *device)
1169 {
1170 	struct storvsc_device *stor_device;
1171 	unsigned long flags;
1172 
1173 	stor_device = hv_get_drvdata(device);
1174 
1175 	spin_lock_irqsave(&device->channel->inbound_lock, flags);
1176 	stor_device->destroy = true;
1177 	spin_unlock_irqrestore(&device->channel->inbound_lock, flags);
1178 
1179 	/*
1180 	 * At this point, all outbound traffic should be disable. We
1181 	 * only allow inbound traffic (responses) to proceed so that
1182 	 * outstanding requests can be completed.
1183 	 */
1184 
1185 	storvsc_wait_to_drain(stor_device);
1186 
1187 	/*
1188 	 * Since we have already drained, we don't need to busy wait
1189 	 * as was done in final_release_stor_device()
1190 	 * Note that we cannot set the ext pointer to NULL until
1191 	 * we have drained - to drain the outgoing packets, we need to
1192 	 * allow incoming packets.
1193 	 */
1194 	spin_lock_irqsave(&device->channel->inbound_lock, flags);
1195 	hv_set_drvdata(device, NULL);
1196 	spin_unlock_irqrestore(&device->channel->inbound_lock, flags);
1197 
1198 	/* Close the channel */
1199 	vmbus_close(device->channel);
1200 
1201 	kfree(stor_device);
1202 	return 0;
1203 }
1204 
1205 static int storvsc_do_io(struct hv_device *device,
1206 			      struct storvsc_cmd_request *request)
1207 {
1208 	struct storvsc_device *stor_device;
1209 	struct vstor_packet *vstor_packet;
1210 	int ret = 0;
1211 
1212 	vstor_packet = &request->vstor_packet;
1213 	stor_device = get_out_stor_device(device);
1214 
1215 	if (!stor_device)
1216 		return -ENODEV;
1217 
1218 
1219 	request->device  = device;
1220 
1221 
1222 	vstor_packet->flags |= REQUEST_COMPLETION_FLAG;
1223 
1224 	vstor_packet->vm_srb.length = (sizeof(struct vmscsi_request) -
1225 					vmscsi_size_delta);
1226 
1227 
1228 	vstor_packet->vm_srb.sense_info_length = sense_buffer_size;
1229 
1230 
1231 	vstor_packet->vm_srb.data_transfer_length =
1232 	request->data_buffer.len;
1233 
1234 	vstor_packet->operation = VSTOR_OPERATION_EXECUTE_SRB;
1235 
1236 	if (request->data_buffer.len) {
1237 		ret = vmbus_sendpacket_multipagebuffer(device->channel,
1238 				&request->data_buffer,
1239 				vstor_packet,
1240 				(sizeof(struct vstor_packet) -
1241 				vmscsi_size_delta),
1242 				(unsigned long)request);
1243 	} else {
1244 		ret = vmbus_sendpacket(device->channel, vstor_packet,
1245 			       (sizeof(struct vstor_packet) -
1246 				vmscsi_size_delta),
1247 			       (unsigned long)request,
1248 			       VM_PKT_DATA_INBAND,
1249 			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
1250 	}
1251 
1252 	if (ret != 0)
1253 		return ret;
1254 
1255 	atomic_inc(&stor_device->num_outstanding_req);
1256 
1257 	return ret;
1258 }
1259 
1260 static int storvsc_device_alloc(struct scsi_device *sdevice)
1261 {
1262 	struct stor_mem_pools *memp;
1263 	int number = STORVSC_MIN_BUF_NR;
1264 
1265 	memp = kzalloc(sizeof(struct stor_mem_pools), GFP_KERNEL);
1266 	if (!memp)
1267 		return -ENOMEM;
1268 
1269 	memp->request_pool =
1270 		kmem_cache_create(dev_name(&sdevice->sdev_dev),
1271 				sizeof(struct storvsc_cmd_request), 0,
1272 				SLAB_HWCACHE_ALIGN, NULL);
1273 
1274 	if (!memp->request_pool)
1275 		goto err0;
1276 
1277 	memp->request_mempool = mempool_create(number, mempool_alloc_slab,
1278 						mempool_free_slab,
1279 						memp->request_pool);
1280 
1281 	if (!memp->request_mempool)
1282 		goto err1;
1283 
1284 	sdevice->hostdata = memp;
1285 
1286 	return 0;
1287 
1288 err1:
1289 	kmem_cache_destroy(memp->request_pool);
1290 
1291 err0:
1292 	kfree(memp);
1293 	return -ENOMEM;
1294 }
1295 
1296 static void storvsc_device_destroy(struct scsi_device *sdevice)
1297 {
1298 	struct stor_mem_pools *memp = sdevice->hostdata;
1299 
1300 	mempool_destroy(memp->request_mempool);
1301 	kmem_cache_destroy(memp->request_pool);
1302 	kfree(memp);
1303 	sdevice->hostdata = NULL;
1304 }
1305 
1306 static int storvsc_device_configure(struct scsi_device *sdevice)
1307 {
1308 	scsi_adjust_queue_depth(sdevice, MSG_SIMPLE_TAG,
1309 				STORVSC_MAX_IO_REQUESTS);
1310 
1311 	blk_queue_max_segment_size(sdevice->request_queue, PAGE_SIZE);
1312 
1313 	blk_queue_bounce_limit(sdevice->request_queue, BLK_BOUNCE_ANY);
1314 
1315 	blk_queue_rq_timeout(sdevice->request_queue, (storvsc_timeout * HZ));
1316 
1317 	sdevice->no_write_same = 1;
1318 
1319 	return 0;
1320 }
1321 
1322 static int storvsc_get_chs(struct scsi_device *sdev, struct block_device * bdev,
1323 			   sector_t capacity, int *info)
1324 {
1325 	sector_t nsect = capacity;
1326 	sector_t cylinders = nsect;
1327 	int heads, sectors_pt;
1328 
1329 	/*
1330 	 * We are making up these values; let us keep it simple.
1331 	 */
1332 	heads = 0xff;
1333 	sectors_pt = 0x3f;      /* Sectors per track */
1334 	sector_div(cylinders, heads * sectors_pt);
1335 	if ((sector_t)(cylinders + 1) * heads * sectors_pt < nsect)
1336 		cylinders = 0xffff;
1337 
1338 	info[0] = heads;
1339 	info[1] = sectors_pt;
1340 	info[2] = (int)cylinders;
1341 
1342 	return 0;
1343 }
1344 
1345 static int storvsc_host_reset_handler(struct scsi_cmnd *scmnd)
1346 {
1347 	struct hv_host_device *host_dev = shost_priv(scmnd->device->host);
1348 	struct hv_device *device = host_dev->dev;
1349 
1350 	struct storvsc_device *stor_device;
1351 	struct storvsc_cmd_request *request;
1352 	struct vstor_packet *vstor_packet;
1353 	int ret, t;
1354 
1355 
1356 	stor_device = get_out_stor_device(device);
1357 	if (!stor_device)
1358 		return FAILED;
1359 
1360 	request = &stor_device->reset_request;
1361 	vstor_packet = &request->vstor_packet;
1362 
1363 	init_completion(&request->wait_event);
1364 
1365 	vstor_packet->operation = VSTOR_OPERATION_RESET_BUS;
1366 	vstor_packet->flags = REQUEST_COMPLETION_FLAG;
1367 	vstor_packet->vm_srb.path_id = stor_device->path_id;
1368 
1369 	ret = vmbus_sendpacket(device->channel, vstor_packet,
1370 			       (sizeof(struct vstor_packet) -
1371 				vmscsi_size_delta),
1372 			       (unsigned long)&stor_device->reset_request,
1373 			       VM_PKT_DATA_INBAND,
1374 			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
1375 	if (ret != 0)
1376 		return FAILED;
1377 
1378 	t = wait_for_completion_timeout(&request->wait_event, 5*HZ);
1379 	if (t == 0)
1380 		return TIMEOUT_ERROR;
1381 
1382 
1383 	/*
1384 	 * At this point, all outstanding requests in the adapter
1385 	 * should have been flushed out and return to us
1386 	 * There is a potential race here where the host may be in
1387 	 * the process of responding when we return from here.
1388 	 * Just wait for all in-transit packets to be accounted for
1389 	 * before we return from here.
1390 	 */
1391 	storvsc_wait_to_drain(stor_device);
1392 
1393 	return SUCCESS;
1394 }
1395 
1396 static bool storvsc_scsi_cmd_ok(struct scsi_cmnd *scmnd)
1397 {
1398 	bool allowed = true;
1399 	u8 scsi_op = scmnd->cmnd[0];
1400 
1401 	switch (scsi_op) {
1402 	/* the host does not handle WRITE_SAME, log accident usage */
1403 	case WRITE_SAME:
1404 	/*
1405 	 * smartd sends this command and the host does not handle
1406 	 * this. So, don't send it.
1407 	 */
1408 	case SET_WINDOW:
1409 		scmnd->result = ILLEGAL_REQUEST << 16;
1410 		allowed = false;
1411 		break;
1412 	default:
1413 		break;
1414 	}
1415 	return allowed;
1416 }
1417 
1418 static int storvsc_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *scmnd)
1419 {
1420 	int ret;
1421 	struct hv_host_device *host_dev = shost_priv(host);
1422 	struct hv_device *dev = host_dev->dev;
1423 	struct storvsc_cmd_request *cmd_request;
1424 	unsigned int request_size = 0;
1425 	int i;
1426 	struct scatterlist *sgl;
1427 	unsigned int sg_count = 0;
1428 	struct vmscsi_request *vm_srb;
1429 	struct stor_mem_pools *memp = scmnd->device->hostdata;
1430 
1431 	if (!storvsc_scsi_cmd_ok(scmnd)) {
1432 		scmnd->scsi_done(scmnd);
1433 		return 0;
1434 	}
1435 
1436 	request_size = sizeof(struct storvsc_cmd_request);
1437 
1438 	cmd_request = mempool_alloc(memp->request_mempool,
1439 				       GFP_ATOMIC);
1440 
1441 	/*
1442 	 * We might be invoked in an interrupt context; hence
1443 	 * mempool_alloc() can fail.
1444 	 */
1445 	if (!cmd_request)
1446 		return SCSI_MLQUEUE_DEVICE_BUSY;
1447 
1448 	memset(cmd_request, 0, sizeof(struct storvsc_cmd_request));
1449 
1450 	/* Setup the cmd request */
1451 	cmd_request->cmd = scmnd;
1452 
1453 	scmnd->host_scribble = (unsigned char *)cmd_request;
1454 
1455 	vm_srb = &cmd_request->vstor_packet.vm_srb;
1456 	vm_srb->win8_extension.time_out_value = 60;
1457 
1458 
1459 	/* Build the SRB */
1460 	switch (scmnd->sc_data_direction) {
1461 	case DMA_TO_DEVICE:
1462 		vm_srb->data_in = WRITE_TYPE;
1463 		vm_srb->win8_extension.srb_flags |= SRB_FLAGS_DATA_OUT;
1464 		vm_srb->win8_extension.srb_flags |=
1465 			(SRB_FLAGS_QUEUE_ACTION_ENABLE |
1466 			SRB_FLAGS_DISABLE_SYNCH_TRANSFER);
1467 		break;
1468 	case DMA_FROM_DEVICE:
1469 		vm_srb->data_in = READ_TYPE;
1470 		vm_srb->win8_extension.srb_flags |= SRB_FLAGS_DATA_IN;
1471 		vm_srb->win8_extension.srb_flags |=
1472 			(SRB_FLAGS_QUEUE_ACTION_ENABLE |
1473 			SRB_FLAGS_DISABLE_SYNCH_TRANSFER);
1474 		break;
1475 	default:
1476 		vm_srb->data_in = UNKNOWN_TYPE;
1477 		vm_srb->win8_extension.srb_flags = 0;
1478 		break;
1479 	}
1480 
1481 
1482 	vm_srb->port_number = host_dev->port;
1483 	vm_srb->path_id = scmnd->device->channel;
1484 	vm_srb->target_id = scmnd->device->id;
1485 	vm_srb->lun = scmnd->device->lun;
1486 
1487 	vm_srb->cdb_length = scmnd->cmd_len;
1488 
1489 	memcpy(vm_srb->cdb, scmnd->cmnd, vm_srb->cdb_length);
1490 
1491 	cmd_request->sense_buffer = scmnd->sense_buffer;
1492 
1493 
1494 	cmd_request->data_buffer.len = scsi_bufflen(scmnd);
1495 	if (scsi_sg_count(scmnd)) {
1496 		sgl = (struct scatterlist *)scsi_sglist(scmnd);
1497 		sg_count = scsi_sg_count(scmnd);
1498 
1499 		/* check if we need to bounce the sgl */
1500 		if (do_bounce_buffer(sgl, scsi_sg_count(scmnd)) != -1) {
1501 			cmd_request->bounce_sgl =
1502 				create_bounce_buffer(sgl, scsi_sg_count(scmnd),
1503 						     scsi_bufflen(scmnd),
1504 						     vm_srb->data_in);
1505 			if (!cmd_request->bounce_sgl) {
1506 				ret = SCSI_MLQUEUE_HOST_BUSY;
1507 				goto queue_error;
1508 			}
1509 
1510 			cmd_request->bounce_sgl_count =
1511 				ALIGN(scsi_bufflen(scmnd), PAGE_SIZE) >>
1512 					PAGE_SHIFT;
1513 
1514 			if (vm_srb->data_in == WRITE_TYPE)
1515 				copy_to_bounce_buffer(sgl,
1516 					cmd_request->bounce_sgl,
1517 					scsi_sg_count(scmnd));
1518 
1519 			sgl = cmd_request->bounce_sgl;
1520 			sg_count = cmd_request->bounce_sgl_count;
1521 		}
1522 
1523 		cmd_request->data_buffer.offset = sgl[0].offset;
1524 
1525 		for (i = 0; i < sg_count; i++)
1526 			cmd_request->data_buffer.pfn_array[i] =
1527 				page_to_pfn(sg_page((&sgl[i])));
1528 
1529 	} else if (scsi_sglist(scmnd)) {
1530 		cmd_request->data_buffer.offset =
1531 			virt_to_phys(scsi_sglist(scmnd)) & (PAGE_SIZE-1);
1532 		cmd_request->data_buffer.pfn_array[0] =
1533 			virt_to_phys(scsi_sglist(scmnd)) >> PAGE_SHIFT;
1534 	}
1535 
1536 	/* Invokes the vsc to start an IO */
1537 	ret = storvsc_do_io(dev, cmd_request);
1538 
1539 	if (ret == -EAGAIN) {
1540 		/* no more space */
1541 
1542 		if (cmd_request->bounce_sgl_count) {
1543 			destroy_bounce_buffer(cmd_request->bounce_sgl,
1544 					cmd_request->bounce_sgl_count);
1545 
1546 			ret = SCSI_MLQUEUE_DEVICE_BUSY;
1547 			goto queue_error;
1548 		}
1549 	}
1550 
1551 	return 0;
1552 
1553 queue_error:
1554 	mempool_free(cmd_request, memp->request_mempool);
1555 	scmnd->host_scribble = NULL;
1556 	return ret;
1557 }
1558 
1559 static struct scsi_host_template scsi_driver = {
1560 	.module	=		THIS_MODULE,
1561 	.name =			"storvsc_host_t",
1562 	.bios_param =		storvsc_get_chs,
1563 	.queuecommand =		storvsc_queuecommand,
1564 	.eh_host_reset_handler =	storvsc_host_reset_handler,
1565 	.slave_alloc =		storvsc_device_alloc,
1566 	.slave_destroy =	storvsc_device_destroy,
1567 	.slave_configure =	storvsc_device_configure,
1568 	.cmd_per_lun =		1,
1569 	/* 64 max_queue * 1 target */
1570 	.can_queue =		STORVSC_MAX_IO_REQUESTS*STORVSC_MAX_TARGETS,
1571 	.this_id =		-1,
1572 	/* no use setting to 0 since ll_blk_rw reset it to 1 */
1573 	/* currently 32 */
1574 	.sg_tablesize =		MAX_MULTIPAGE_BUFFER_COUNT,
1575 	.use_clustering =	DISABLE_CLUSTERING,
1576 	/* Make sure we dont get a sg segment crosses a page boundary */
1577 	.dma_boundary =		PAGE_SIZE-1,
1578 };
1579 
1580 enum {
1581 	SCSI_GUID,
1582 	IDE_GUID,
1583 };
1584 
1585 static const struct hv_vmbus_device_id id_table[] = {
1586 	/* SCSI guid */
1587 	{ HV_SCSI_GUID,
1588 	  .driver_data = SCSI_GUID
1589 	},
1590 	/* IDE guid */
1591 	{ HV_IDE_GUID,
1592 	  .driver_data = IDE_GUID
1593 	},
1594 	{ },
1595 };
1596 
1597 MODULE_DEVICE_TABLE(vmbus, id_table);
1598 
1599 static int storvsc_probe(struct hv_device *device,
1600 			const struct hv_vmbus_device_id *dev_id)
1601 {
1602 	int ret;
1603 	struct Scsi_Host *host;
1604 	struct hv_host_device *host_dev;
1605 	bool dev_is_ide = ((dev_id->driver_data == IDE_GUID) ? true : false);
1606 	int target = 0;
1607 	struct storvsc_device *stor_device;
1608 
1609 	/*
1610 	 * Based on the windows host we are running on,
1611 	 * set state to properly communicate with the host.
1612 	 */
1613 
1614 	if (vmbus_proto_version == VERSION_WIN8) {
1615 		sense_buffer_size = POST_WIN7_STORVSC_SENSE_BUFFER_SIZE;
1616 		vmscsi_size_delta = 0;
1617 		vmstor_current_major = VMSTOR_WIN8_MAJOR;
1618 		vmstor_current_minor = VMSTOR_WIN8_MINOR;
1619 	} else {
1620 		sense_buffer_size = PRE_WIN8_STORVSC_SENSE_BUFFER_SIZE;
1621 		vmscsi_size_delta = sizeof(struct vmscsi_win8_extension);
1622 		vmstor_current_major = VMSTOR_WIN7_MAJOR;
1623 		vmstor_current_minor = VMSTOR_WIN7_MINOR;
1624 	}
1625 
1626 
1627 	host = scsi_host_alloc(&scsi_driver,
1628 			       sizeof(struct hv_host_device));
1629 	if (!host)
1630 		return -ENOMEM;
1631 
1632 	host_dev = shost_priv(host);
1633 	memset(host_dev, 0, sizeof(struct hv_host_device));
1634 
1635 	host_dev->port = host->host_no;
1636 	host_dev->dev = device;
1637 
1638 
1639 	stor_device = kzalloc(sizeof(struct storvsc_device), GFP_KERNEL);
1640 	if (!stor_device) {
1641 		ret = -ENOMEM;
1642 		goto err_out0;
1643 	}
1644 
1645 	stor_device->destroy = false;
1646 	init_waitqueue_head(&stor_device->waiting_to_drain);
1647 	stor_device->device = device;
1648 	stor_device->host = host;
1649 	hv_set_drvdata(device, stor_device);
1650 
1651 	stor_device->port_number = host->host_no;
1652 	ret = storvsc_connect_to_vsp(device, storvsc_ringbuffer_size);
1653 	if (ret)
1654 		goto err_out1;
1655 
1656 	host_dev->path = stor_device->path_id;
1657 	host_dev->target = stor_device->target_id;
1658 
1659 	/* max # of devices per target */
1660 	host->max_lun = STORVSC_MAX_LUNS_PER_TARGET;
1661 	/* max # of targets per channel */
1662 	host->max_id = STORVSC_MAX_TARGETS;
1663 	/* max # of channels */
1664 	host->max_channel = STORVSC_MAX_CHANNELS - 1;
1665 	/* max cmd length */
1666 	host->max_cmd_len = STORVSC_MAX_CMD_LEN;
1667 
1668 	/* Register the HBA and start the scsi bus scan */
1669 	ret = scsi_add_host(host, &device->device);
1670 	if (ret != 0)
1671 		goto err_out2;
1672 
1673 	if (!dev_is_ide) {
1674 		scsi_scan_host(host);
1675 	} else {
1676 		target = (device->dev_instance.b[5] << 8 |
1677 			 device->dev_instance.b[4]);
1678 		ret = scsi_add_device(host, 0, target, 0);
1679 		if (ret) {
1680 			scsi_remove_host(host);
1681 			goto err_out2;
1682 		}
1683 	}
1684 	return 0;
1685 
1686 err_out2:
1687 	/*
1688 	 * Once we have connected with the host, we would need to
1689 	 * to invoke storvsc_dev_remove() to rollback this state and
1690 	 * this call also frees up the stor_device; hence the jump around
1691 	 * err_out1 label.
1692 	 */
1693 	storvsc_dev_remove(device);
1694 	goto err_out0;
1695 
1696 err_out1:
1697 	kfree(stor_device);
1698 
1699 err_out0:
1700 	scsi_host_put(host);
1701 	return ret;
1702 }
1703 
1704 static int storvsc_remove(struct hv_device *dev)
1705 {
1706 	struct storvsc_device *stor_device = hv_get_drvdata(dev);
1707 	struct Scsi_Host *host = stor_device->host;
1708 
1709 	scsi_remove_host(host);
1710 	storvsc_dev_remove(dev);
1711 	scsi_host_put(host);
1712 
1713 	return 0;
1714 }
1715 
1716 static struct hv_driver storvsc_drv = {
1717 	.name = KBUILD_MODNAME,
1718 	.id_table = id_table,
1719 	.probe = storvsc_probe,
1720 	.remove = storvsc_remove,
1721 };
1722 
1723 static int __init storvsc_drv_init(void)
1724 {
1725 	u32 max_outstanding_req_per_channel;
1726 
1727 	/*
1728 	 * Divide the ring buffer data size (which is 1 page less
1729 	 * than the ring buffer size since that page is reserved for
1730 	 * the ring buffer indices) by the max request size (which is
1731 	 * vmbus_channel_packet_multipage_buffer + struct vstor_packet + u64)
1732 	 */
1733 	max_outstanding_req_per_channel =
1734 		((storvsc_ringbuffer_size - PAGE_SIZE) /
1735 		ALIGN(MAX_MULTIPAGE_BUFFER_PACKET +
1736 		sizeof(struct vstor_packet) + sizeof(u64) -
1737 		vmscsi_size_delta,
1738 		sizeof(u64)));
1739 
1740 	if (max_outstanding_req_per_channel <
1741 	    STORVSC_MAX_IO_REQUESTS)
1742 		return -EINVAL;
1743 
1744 	return vmbus_driver_register(&storvsc_drv);
1745 }
1746 
1747 static void __exit storvsc_drv_exit(void)
1748 {
1749 	vmbus_driver_unregister(&storvsc_drv);
1750 }
1751 
1752 MODULE_LICENSE("GPL");
1753 MODULE_VERSION(HV_DRV_VERSION);
1754 MODULE_DESCRIPTION("Microsoft Hyper-V virtual storage driver");
1755 module_init(storvsc_drv_init);
1756 module_exit(storvsc_drv_exit);
1757