xref: /linux/drivers/scsi/storvsc_drv.c (revision 93d90ad708b8da6efc0e487b66111aa9db7f70c7)
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 <linux/blkdev.h>
37 #include <scsi/scsi.h>
38 #include <scsi/scsi_cmnd.h>
39 #include <scsi/scsi_host.h>
40 #include <scsi/scsi_device.h>
41 #include <scsi/scsi_tcq.h>
42 #include <scsi/scsi_eh.h>
43 #include <scsi/scsi_devinfo.h>
44 #include <scsi/scsi_dbg.h>
45 
46 /*
47  * All wire protocol details (storage protocol between the guest and the host)
48  * are consolidated here.
49  *
50  * Begin protocol definitions.
51  */
52 
53 /*
54  * Version history:
55  * V1 Beta: 0.1
56  * V1 RC < 2008/1/31: 1.0
57  * V1 RC > 2008/1/31:  2.0
58  * Win7: 4.2
59  * Win8: 5.1
60  */
61 
62 
63 #define VMSTOR_WIN7_MAJOR 4
64 #define VMSTOR_WIN7_MINOR 2
65 
66 #define VMSTOR_WIN8_MAJOR 5
67 #define VMSTOR_WIN8_MINOR 1
68 
69 
70 /*  Packet structure describing virtual storage requests. */
71 enum vstor_packet_operation {
72 	VSTOR_OPERATION_COMPLETE_IO		= 1,
73 	VSTOR_OPERATION_REMOVE_DEVICE		= 2,
74 	VSTOR_OPERATION_EXECUTE_SRB		= 3,
75 	VSTOR_OPERATION_RESET_LUN		= 4,
76 	VSTOR_OPERATION_RESET_ADAPTER		= 5,
77 	VSTOR_OPERATION_RESET_BUS		= 6,
78 	VSTOR_OPERATION_BEGIN_INITIALIZATION	= 7,
79 	VSTOR_OPERATION_END_INITIALIZATION	= 8,
80 	VSTOR_OPERATION_QUERY_PROTOCOL_VERSION	= 9,
81 	VSTOR_OPERATION_QUERY_PROPERTIES	= 10,
82 	VSTOR_OPERATION_ENUMERATE_BUS		= 11,
83 	VSTOR_OPERATION_FCHBA_DATA              = 12,
84 	VSTOR_OPERATION_CREATE_SUB_CHANNELS     = 13,
85 	VSTOR_OPERATION_MAXIMUM                 = 13
86 };
87 
88 /*
89  * WWN packet for Fibre Channel HBA
90  */
91 
92 struct hv_fc_wwn_packet {
93 	bool	primary_active;
94 	u8	reserved1;
95 	u8	reserved2;
96 	u8	primary_port_wwn[8];
97 	u8	primary_node_wwn[8];
98 	u8	secondary_port_wwn[8];
99 	u8	secondary_node_wwn[8];
100 };
101 
102 
103 
104 /*
105  * SRB Flag Bits
106  */
107 
108 #define SRB_FLAGS_QUEUE_ACTION_ENABLE		0x00000002
109 #define SRB_FLAGS_DISABLE_DISCONNECT		0x00000004
110 #define SRB_FLAGS_DISABLE_SYNCH_TRANSFER	0x00000008
111 #define SRB_FLAGS_BYPASS_FROZEN_QUEUE		0x00000010
112 #define SRB_FLAGS_DISABLE_AUTOSENSE		0x00000020
113 #define SRB_FLAGS_DATA_IN			0x00000040
114 #define SRB_FLAGS_DATA_OUT			0x00000080
115 #define SRB_FLAGS_NO_DATA_TRANSFER		0x00000000
116 #define SRB_FLAGS_UNSPECIFIED_DIRECTION	(SRB_FLAGS_DATA_IN | SRB_FLAGS_DATA_OUT)
117 #define SRB_FLAGS_NO_QUEUE_FREEZE		0x00000100
118 #define SRB_FLAGS_ADAPTER_CACHE_ENABLE		0x00000200
119 #define SRB_FLAGS_FREE_SENSE_BUFFER		0x00000400
120 
121 /*
122  * This flag indicates the request is part of the workflow for processing a D3.
123  */
124 #define SRB_FLAGS_D3_PROCESSING			0x00000800
125 #define SRB_FLAGS_IS_ACTIVE			0x00010000
126 #define SRB_FLAGS_ALLOCATED_FROM_ZONE		0x00020000
127 #define SRB_FLAGS_SGLIST_FROM_POOL		0x00040000
128 #define SRB_FLAGS_BYPASS_LOCKED_QUEUE		0x00080000
129 #define SRB_FLAGS_NO_KEEP_AWAKE			0x00100000
130 #define SRB_FLAGS_PORT_DRIVER_ALLOCSENSE	0x00200000
131 #define SRB_FLAGS_PORT_DRIVER_SENSEHASPORT	0x00400000
132 #define SRB_FLAGS_DONT_START_NEXT_PACKET	0x00800000
133 #define SRB_FLAGS_PORT_DRIVER_RESERVED		0x0F000000
134 #define SRB_FLAGS_CLASS_DRIVER_RESERVED		0xF0000000
135 
136 
137 /*
138  * Platform neutral description of a scsi request -
139  * this remains the same across the write regardless of 32/64 bit
140  * note: it's patterned off the SCSI_PASS_THROUGH structure
141  */
142 #define STORVSC_MAX_CMD_LEN			0x10
143 
144 #define POST_WIN7_STORVSC_SENSE_BUFFER_SIZE	0x14
145 #define PRE_WIN8_STORVSC_SENSE_BUFFER_SIZE	0x12
146 
147 #define STORVSC_SENSE_BUFFER_SIZE		0x14
148 #define STORVSC_MAX_BUF_LEN_WITH_PADDING	0x14
149 
150 /*
151  * Sense buffer size changed in win8; have a run-time
152  * variable to track the size we should use.
153  */
154 static int sense_buffer_size;
155 
156 /*
157  * The size of the vmscsi_request has changed in win8. The
158  * additional size is because of new elements added to the
159  * structure. These elements are valid only when we are talking
160  * to a win8 host.
161  * Track the correction to size we need to apply.
162  */
163 
164 static int vmscsi_size_delta;
165 static int vmstor_current_major;
166 static int vmstor_current_minor;
167 
168 struct vmscsi_win8_extension {
169 	/*
170 	 * The following were added in Windows 8
171 	 */
172 	u16 reserve;
173 	u8  queue_tag;
174 	u8  queue_action;
175 	u32 srb_flags;
176 	u32 time_out_value;
177 	u32 queue_sort_ey;
178 } __packed;
179 
180 struct vmscsi_request {
181 	u16 length;
182 	u8 srb_status;
183 	u8 scsi_status;
184 
185 	u8  port_number;
186 	u8  path_id;
187 	u8  target_id;
188 	u8  lun;
189 
190 	u8  cdb_length;
191 	u8  sense_info_length;
192 	u8  data_in;
193 	u8  reserved;
194 
195 	u32 data_transfer_length;
196 
197 	union {
198 		u8 cdb[STORVSC_MAX_CMD_LEN];
199 		u8 sense_data[STORVSC_SENSE_BUFFER_SIZE];
200 		u8 reserved_array[STORVSC_MAX_BUF_LEN_WITH_PADDING];
201 	};
202 	/*
203 	 * The following was added in win8.
204 	 */
205 	struct vmscsi_win8_extension win8_extension;
206 
207 } __attribute((packed));
208 
209 
210 /*
211  * This structure is sent during the intialization phase to get the different
212  * properties of the channel.
213  */
214 
215 #define STORAGE_CHANNEL_SUPPORTS_MULTI_CHANNEL		0x1
216 
217 struct vmstorage_channel_properties {
218 	u32 reserved;
219 	u16 max_channel_cnt;
220 	u16 reserved1;
221 
222 	u32 flags;
223 	u32   max_transfer_bytes;
224 
225 	u64  reserved2;
226 } __packed;
227 
228 /*  This structure is sent during the storage protocol negotiations. */
229 struct vmstorage_protocol_version {
230 	/* Major (MSW) and minor (LSW) version numbers. */
231 	u16 major_minor;
232 
233 	/*
234 	 * Revision number is auto-incremented whenever this file is changed
235 	 * (See FILL_VMSTOR_REVISION macro above).  Mismatch does not
236 	 * definitely indicate incompatibility--but it does indicate mismatched
237 	 * builds.
238 	 * This is only used on the windows side. Just set it to 0.
239 	 */
240 	u16 revision;
241 } __packed;
242 
243 /* Channel Property Flags */
244 #define STORAGE_CHANNEL_REMOVABLE_FLAG		0x1
245 #define STORAGE_CHANNEL_EMULATED_IDE_FLAG	0x2
246 
247 struct vstor_packet {
248 	/* Requested operation type */
249 	enum vstor_packet_operation operation;
250 
251 	/*  Flags - see below for values */
252 	u32 flags;
253 
254 	/* Status of the request returned from the server side. */
255 	u32 status;
256 
257 	/* Data payload area */
258 	union {
259 		/*
260 		 * Structure used to forward SCSI commands from the
261 		 * client to the server.
262 		 */
263 		struct vmscsi_request vm_srb;
264 
265 		/* Structure used to query channel properties. */
266 		struct vmstorage_channel_properties storage_channel_properties;
267 
268 		/* Used during version negotiations. */
269 		struct vmstorage_protocol_version version;
270 
271 		/* Fibre channel address packet */
272 		struct hv_fc_wwn_packet wwn_packet;
273 
274 		/* Number of sub-channels to create */
275 		u16 sub_channel_count;
276 
277 		/* This will be the maximum of the union members */
278 		u8  buffer[0x34];
279 	};
280 } __packed;
281 
282 /*
283  * Packet Flags:
284  *
285  * This flag indicates that the server should send back a completion for this
286  * packet.
287  */
288 
289 #define REQUEST_COMPLETION_FLAG	0x1
290 
291 /* Matches Windows-end */
292 enum storvsc_request_type {
293 	WRITE_TYPE = 0,
294 	READ_TYPE,
295 	UNKNOWN_TYPE,
296 };
297 
298 /*
299  * SRB status codes and masks; a subset of the codes used here.
300  */
301 
302 #define SRB_STATUS_AUTOSENSE_VALID	0x80
303 #define SRB_STATUS_INVALID_LUN	0x20
304 #define SRB_STATUS_SUCCESS	0x01
305 #define SRB_STATUS_ABORTED	0x02
306 #define SRB_STATUS_ERROR	0x04
307 
308 /*
309  * This is the end of Protocol specific defines.
310  */
311 
312 
313 /*
314  * We setup a mempool to allocate request structures for this driver
315  * on a per-lun basis. The following define specifies the number of
316  * elements in the pool.
317  */
318 
319 #define STORVSC_MIN_BUF_NR				64
320 static int storvsc_ringbuffer_size = (20 * PAGE_SIZE);
321 
322 module_param(storvsc_ringbuffer_size, int, S_IRUGO);
323 MODULE_PARM_DESC(storvsc_ringbuffer_size, "Ring buffer size (bytes)");
324 
325 /*
326  * Timeout in seconds for all devices managed by this driver.
327  */
328 static int storvsc_timeout = 180;
329 
330 static int msft_blist_flags = BLIST_TRY_VPD_PAGES;
331 
332 #define STORVSC_MAX_IO_REQUESTS				200
333 
334 static void storvsc_on_channel_callback(void *context);
335 
336 #define STORVSC_MAX_LUNS_PER_TARGET			255
337 #define STORVSC_MAX_TARGETS				2
338 #define STORVSC_MAX_CHANNELS				8
339 
340 #define STORVSC_FC_MAX_LUNS_PER_TARGET			255
341 #define STORVSC_FC_MAX_TARGETS				128
342 #define STORVSC_FC_MAX_CHANNELS				8
343 
344 #define STORVSC_IDE_MAX_LUNS_PER_TARGET			64
345 #define STORVSC_IDE_MAX_TARGETS				1
346 #define STORVSC_IDE_MAX_CHANNELS			1
347 
348 struct storvsc_cmd_request {
349 	struct list_head entry;
350 	struct scsi_cmnd *cmd;
351 
352 	unsigned int bounce_sgl_count;
353 	struct scatterlist *bounce_sgl;
354 
355 	struct hv_device *device;
356 
357 	/* Synchronize the request/response if needed */
358 	struct completion wait_event;
359 
360 	unsigned char *sense_buffer;
361 	struct hv_multipage_buffer data_buffer;
362 	struct vstor_packet vstor_packet;
363 };
364 
365 
366 /* A storvsc device is a device object that contains a vmbus channel */
367 struct storvsc_device {
368 	struct hv_device *device;
369 
370 	bool	 destroy;
371 	bool	 drain_notify;
372 	bool	 open_sub_channel;
373 	atomic_t num_outstanding_req;
374 	struct Scsi_Host *host;
375 
376 	wait_queue_head_t waiting_to_drain;
377 
378 	/*
379 	 * Each unique Port/Path/Target represents 1 channel ie scsi
380 	 * controller. In reality, the pathid, targetid is always 0
381 	 * and the port is set by us
382 	 */
383 	unsigned int port_number;
384 	unsigned char path_id;
385 	unsigned char target_id;
386 
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 stor_mem_pools {
393 	struct kmem_cache *request_pool;
394 	mempool_t *request_mempool;
395 };
396 
397 struct hv_host_device {
398 	struct hv_device *dev;
399 	unsigned int port;
400 	unsigned char path;
401 	unsigned char target;
402 };
403 
404 struct storvsc_scan_work {
405 	struct work_struct work;
406 	struct Scsi_Host *host;
407 	uint lun;
408 };
409 
410 static void storvsc_device_scan(struct work_struct *work)
411 {
412 	struct storvsc_scan_work *wrk;
413 	uint lun;
414 	struct scsi_device *sdev;
415 
416 	wrk = container_of(work, struct storvsc_scan_work, work);
417 	lun = wrk->lun;
418 
419 	sdev = scsi_device_lookup(wrk->host, 0, 0, lun);
420 	if (!sdev)
421 		goto done;
422 	scsi_rescan_device(&sdev->sdev_gendev);
423 	scsi_device_put(sdev);
424 
425 done:
426 	kfree(wrk);
427 }
428 
429 static void storvsc_bus_scan(struct work_struct *work)
430 {
431 	struct storvsc_scan_work *wrk;
432 	int id, order_id;
433 
434 	wrk = container_of(work, struct storvsc_scan_work, work);
435 	for (id = 0; id < wrk->host->max_id; ++id) {
436 		if (wrk->host->reverse_ordering)
437 			order_id = wrk->host->max_id - id - 1;
438 		else
439 			order_id = id;
440 
441 		scsi_scan_target(&wrk->host->shost_gendev, 0,
442 				order_id, SCAN_WILD_CARD, 1);
443 	}
444 	kfree(wrk);
445 }
446 
447 static void storvsc_remove_lun(struct work_struct *work)
448 {
449 	struct storvsc_scan_work *wrk;
450 	struct scsi_device *sdev;
451 
452 	wrk = container_of(work, struct storvsc_scan_work, work);
453 	if (!scsi_host_get(wrk->host))
454 		goto done;
455 
456 	sdev = scsi_device_lookup(wrk->host, 0, 0, wrk->lun);
457 
458 	if (sdev) {
459 		scsi_remove_device(sdev);
460 		scsi_device_put(sdev);
461 	}
462 	scsi_host_put(wrk->host);
463 
464 done:
465 	kfree(wrk);
466 }
467 
468 /*
469  * Major/minor macros.  Minor version is in LSB, meaning that earlier flat
470  * version numbers will be interpreted as "0.x" (i.e., 1 becomes 0.1).
471  */
472 
473 static inline u16 storvsc_get_version(u8 major, u8 minor)
474 {
475 	u16 version;
476 
477 	version = ((major << 8) | minor);
478 	return version;
479 }
480 
481 /*
482  * We can get incoming messages from the host that are not in response to
483  * messages that we have sent out. An example of this would be messages
484  * received by the guest to notify dynamic addition/removal of LUNs. To
485  * deal with potential race conditions where the driver may be in the
486  * midst of being unloaded when we might receive an unsolicited message
487  * from the host, we have implemented a mechanism to gurantee sequential
488  * consistency:
489  *
490  * 1) Once the device is marked as being destroyed, we will fail all
491  *    outgoing messages.
492  * 2) We permit incoming messages when the device is being destroyed,
493  *    only to properly account for messages already sent out.
494  */
495 
496 static inline struct storvsc_device *get_out_stor_device(
497 					struct hv_device *device)
498 {
499 	struct storvsc_device *stor_device;
500 
501 	stor_device = hv_get_drvdata(device);
502 
503 	if (stor_device && stor_device->destroy)
504 		stor_device = NULL;
505 
506 	return stor_device;
507 }
508 
509 
510 static inline void storvsc_wait_to_drain(struct storvsc_device *dev)
511 {
512 	dev->drain_notify = true;
513 	wait_event(dev->waiting_to_drain,
514 		   atomic_read(&dev->num_outstanding_req) == 0);
515 	dev->drain_notify = false;
516 }
517 
518 static inline struct storvsc_device *get_in_stor_device(
519 					struct hv_device *device)
520 {
521 	struct storvsc_device *stor_device;
522 
523 	stor_device = hv_get_drvdata(device);
524 
525 	if (!stor_device)
526 		goto get_in_err;
527 
528 	/*
529 	 * If the device is being destroyed; allow incoming
530 	 * traffic only to cleanup outstanding requests.
531 	 */
532 
533 	if (stor_device->destroy  &&
534 		(atomic_read(&stor_device->num_outstanding_req) == 0))
535 		stor_device = NULL;
536 
537 get_in_err:
538 	return stor_device;
539 
540 }
541 
542 static void destroy_bounce_buffer(struct scatterlist *sgl,
543 				  unsigned int sg_count)
544 {
545 	int i;
546 	struct page *page_buf;
547 
548 	for (i = 0; i < sg_count; i++) {
549 		page_buf = sg_page((&sgl[i]));
550 		if (page_buf != NULL)
551 			__free_page(page_buf);
552 	}
553 
554 	kfree(sgl);
555 }
556 
557 static int do_bounce_buffer(struct scatterlist *sgl, unsigned int sg_count)
558 {
559 	int i;
560 
561 	/* No need to check */
562 	if (sg_count < 2)
563 		return -1;
564 
565 	/* We have at least 2 sg entries */
566 	for (i = 0; i < sg_count; i++) {
567 		if (i == 0) {
568 			/* make sure 1st one does not have hole */
569 			if (sgl[i].offset + sgl[i].length != PAGE_SIZE)
570 				return i;
571 		} else if (i == sg_count - 1) {
572 			/* make sure last one does not have hole */
573 			if (sgl[i].offset != 0)
574 				return i;
575 		} else {
576 			/* make sure no hole in the middle */
577 			if (sgl[i].length != PAGE_SIZE || sgl[i].offset != 0)
578 				return i;
579 		}
580 	}
581 	return -1;
582 }
583 
584 static struct scatterlist *create_bounce_buffer(struct scatterlist *sgl,
585 						unsigned int sg_count,
586 						unsigned int len,
587 						int write)
588 {
589 	int i;
590 	int num_pages;
591 	struct scatterlist *bounce_sgl;
592 	struct page *page_buf;
593 	unsigned int buf_len = ((write == WRITE_TYPE) ? 0 : PAGE_SIZE);
594 
595 	num_pages = ALIGN(len, PAGE_SIZE) >> PAGE_SHIFT;
596 
597 	bounce_sgl = kcalloc(num_pages, sizeof(struct scatterlist), GFP_ATOMIC);
598 	if (!bounce_sgl)
599 		return NULL;
600 
601 	sg_init_table(bounce_sgl, num_pages);
602 	for (i = 0; i < num_pages; i++) {
603 		page_buf = alloc_page(GFP_ATOMIC);
604 		if (!page_buf)
605 			goto cleanup;
606 		sg_set_page(&bounce_sgl[i], page_buf, buf_len, 0);
607 	}
608 
609 	return bounce_sgl;
610 
611 cleanup:
612 	destroy_bounce_buffer(bounce_sgl, num_pages);
613 	return NULL;
614 }
615 
616 /* Disgusting wrapper functions */
617 static inline unsigned long sg_kmap_atomic(struct scatterlist *sgl, int idx)
618 {
619 	void *addr = kmap_atomic(sg_page(sgl + idx));
620 	return (unsigned long)addr;
621 }
622 
623 static inline void sg_kunmap_atomic(unsigned long addr)
624 {
625 	kunmap_atomic((void *)addr);
626 }
627 
628 
629 /* Assume the original sgl has enough room */
630 static unsigned int copy_from_bounce_buffer(struct scatterlist *orig_sgl,
631 					    struct scatterlist *bounce_sgl,
632 					    unsigned int orig_sgl_count,
633 					    unsigned int bounce_sgl_count)
634 {
635 	int i;
636 	int j = 0;
637 	unsigned long src, dest;
638 	unsigned int srclen, destlen, copylen;
639 	unsigned int total_copied = 0;
640 	unsigned long bounce_addr = 0;
641 	unsigned long dest_addr = 0;
642 	unsigned long flags;
643 
644 	local_irq_save(flags);
645 
646 	for (i = 0; i < orig_sgl_count; i++) {
647 		dest_addr = sg_kmap_atomic(orig_sgl,i) + orig_sgl[i].offset;
648 		dest = dest_addr;
649 		destlen = orig_sgl[i].length;
650 
651 		if (bounce_addr == 0)
652 			bounce_addr = sg_kmap_atomic(bounce_sgl,j);
653 
654 		while (destlen) {
655 			src = bounce_addr + bounce_sgl[j].offset;
656 			srclen = bounce_sgl[j].length - bounce_sgl[j].offset;
657 
658 			copylen = min(srclen, destlen);
659 			memcpy((void *)dest, (void *)src, copylen);
660 
661 			total_copied += copylen;
662 			bounce_sgl[j].offset += copylen;
663 			destlen -= copylen;
664 			dest += copylen;
665 
666 			if (bounce_sgl[j].offset == bounce_sgl[j].length) {
667 				/* full */
668 				sg_kunmap_atomic(bounce_addr);
669 				j++;
670 
671 				/*
672 				 * It is possible that the number of elements
673 				 * in the bounce buffer may not be equal to
674 				 * the number of elements in the original
675 				 * scatter list. Handle this correctly.
676 				 */
677 
678 				if (j == bounce_sgl_count) {
679 					/*
680 					 * We are done; cleanup and return.
681 					 */
682 					sg_kunmap_atomic(dest_addr - orig_sgl[i].offset);
683 					local_irq_restore(flags);
684 					return total_copied;
685 				}
686 
687 				/* if we need to use another bounce buffer */
688 				if (destlen || i != orig_sgl_count - 1)
689 					bounce_addr = sg_kmap_atomic(bounce_sgl,j);
690 			} else if (destlen == 0 && i == orig_sgl_count - 1) {
691 				/* unmap the last bounce that is < PAGE_SIZE */
692 				sg_kunmap_atomic(bounce_addr);
693 			}
694 		}
695 
696 		sg_kunmap_atomic(dest_addr - orig_sgl[i].offset);
697 	}
698 
699 	local_irq_restore(flags);
700 
701 	return total_copied;
702 }
703 
704 /* Assume the bounce_sgl has enough room ie using the create_bounce_buffer() */
705 static unsigned int copy_to_bounce_buffer(struct scatterlist *orig_sgl,
706 					  struct scatterlist *bounce_sgl,
707 					  unsigned int orig_sgl_count)
708 {
709 	int i;
710 	int j = 0;
711 	unsigned long src, dest;
712 	unsigned int srclen, destlen, copylen;
713 	unsigned int total_copied = 0;
714 	unsigned long bounce_addr = 0;
715 	unsigned long src_addr = 0;
716 	unsigned long flags;
717 
718 	local_irq_save(flags);
719 
720 	for (i = 0; i < orig_sgl_count; i++) {
721 		src_addr = sg_kmap_atomic(orig_sgl,i) + orig_sgl[i].offset;
722 		src = src_addr;
723 		srclen = orig_sgl[i].length;
724 
725 		if (bounce_addr == 0)
726 			bounce_addr = sg_kmap_atomic(bounce_sgl,j);
727 
728 		while (srclen) {
729 			/* assume bounce offset always == 0 */
730 			dest = bounce_addr + bounce_sgl[j].length;
731 			destlen = PAGE_SIZE - bounce_sgl[j].length;
732 
733 			copylen = min(srclen, destlen);
734 			memcpy((void *)dest, (void *)src, copylen);
735 
736 			total_copied += copylen;
737 			bounce_sgl[j].length += copylen;
738 			srclen -= copylen;
739 			src += copylen;
740 
741 			if (bounce_sgl[j].length == PAGE_SIZE) {
742 				/* full..move to next entry */
743 				sg_kunmap_atomic(bounce_addr);
744 				j++;
745 
746 				/* if we need to use another bounce buffer */
747 				if (srclen || i != orig_sgl_count - 1)
748 					bounce_addr = sg_kmap_atomic(bounce_sgl,j);
749 
750 			} else if (srclen == 0 && i == orig_sgl_count - 1) {
751 				/* unmap the last bounce that is < PAGE_SIZE */
752 				sg_kunmap_atomic(bounce_addr);
753 			}
754 		}
755 
756 		sg_kunmap_atomic(src_addr - orig_sgl[i].offset);
757 	}
758 
759 	local_irq_restore(flags);
760 
761 	return total_copied;
762 }
763 
764 static void handle_sc_creation(struct vmbus_channel *new_sc)
765 {
766 	struct hv_device *device = new_sc->primary_channel->device_obj;
767 	struct storvsc_device *stor_device;
768 	struct vmstorage_channel_properties props;
769 
770 	stor_device = get_out_stor_device(device);
771 	if (!stor_device)
772 		return;
773 
774 	if (stor_device->open_sub_channel == false)
775 		return;
776 
777 	memset(&props, 0, sizeof(struct vmstorage_channel_properties));
778 
779 	vmbus_open(new_sc,
780 		   storvsc_ringbuffer_size,
781 		   storvsc_ringbuffer_size,
782 		   (void *)&props,
783 		   sizeof(struct vmstorage_channel_properties),
784 		   storvsc_on_channel_callback, new_sc);
785 }
786 
787 static void  handle_multichannel_storage(struct hv_device *device, int max_chns)
788 {
789 	struct storvsc_device *stor_device;
790 	int num_cpus = num_online_cpus();
791 	int num_sc;
792 	struct storvsc_cmd_request *request;
793 	struct vstor_packet *vstor_packet;
794 	int ret, t;
795 
796 	num_sc = ((max_chns > num_cpus) ? num_cpus : max_chns);
797 	stor_device = get_out_stor_device(device);
798 	if (!stor_device)
799 		return;
800 
801 	request = &stor_device->init_request;
802 	vstor_packet = &request->vstor_packet;
803 
804 	stor_device->open_sub_channel = true;
805 	/*
806 	 * Establish a handler for dealing with subchannels.
807 	 */
808 	vmbus_set_sc_create_callback(device->channel, handle_sc_creation);
809 
810 	/*
811 	 * Check to see if sub-channels have already been created. This
812 	 * can happen when this driver is re-loaded after unloading.
813 	 */
814 
815 	if (vmbus_are_subchannels_present(device->channel))
816 		return;
817 
818 	stor_device->open_sub_channel = false;
819 	/*
820 	 * Request the host to create sub-channels.
821 	 */
822 	memset(request, 0, sizeof(struct storvsc_cmd_request));
823 	init_completion(&request->wait_event);
824 	vstor_packet->operation = VSTOR_OPERATION_CREATE_SUB_CHANNELS;
825 	vstor_packet->flags = REQUEST_COMPLETION_FLAG;
826 	vstor_packet->sub_channel_count = num_sc;
827 
828 	ret = vmbus_sendpacket(device->channel, vstor_packet,
829 			       (sizeof(struct vstor_packet) -
830 			       vmscsi_size_delta),
831 			       (unsigned long)request,
832 			       VM_PKT_DATA_INBAND,
833 			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
834 
835 	if (ret != 0)
836 		return;
837 
838 	t = wait_for_completion_timeout(&request->wait_event, 10*HZ);
839 	if (t == 0)
840 		return;
841 
842 	if (vstor_packet->operation != VSTOR_OPERATION_COMPLETE_IO ||
843 	    vstor_packet->status != 0)
844 		return;
845 
846 	/*
847 	 * Now that we created the sub-channels, invoke the check; this
848 	 * may trigger the callback.
849 	 */
850 	stor_device->open_sub_channel = true;
851 	vmbus_are_subchannels_present(device->channel);
852 }
853 
854 static int storvsc_channel_init(struct hv_device *device)
855 {
856 	struct storvsc_device *stor_device;
857 	struct storvsc_cmd_request *request;
858 	struct vstor_packet *vstor_packet;
859 	int ret, t;
860 	int max_chns;
861 	bool process_sub_channels = false;
862 
863 	stor_device = get_out_stor_device(device);
864 	if (!stor_device)
865 		return -ENODEV;
866 
867 	request = &stor_device->init_request;
868 	vstor_packet = &request->vstor_packet;
869 
870 	/*
871 	 * Now, initiate the vsc/vsp initialization protocol on the open
872 	 * channel
873 	 */
874 	memset(request, 0, sizeof(struct storvsc_cmd_request));
875 	init_completion(&request->wait_event);
876 	vstor_packet->operation = VSTOR_OPERATION_BEGIN_INITIALIZATION;
877 	vstor_packet->flags = REQUEST_COMPLETION_FLAG;
878 
879 	ret = vmbus_sendpacket(device->channel, vstor_packet,
880 			       (sizeof(struct vstor_packet) -
881 			       vmscsi_size_delta),
882 			       (unsigned long)request,
883 			       VM_PKT_DATA_INBAND,
884 			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
885 	if (ret != 0)
886 		goto cleanup;
887 
888 	t = wait_for_completion_timeout(&request->wait_event, 5*HZ);
889 	if (t == 0) {
890 		ret = -ETIMEDOUT;
891 		goto cleanup;
892 	}
893 
894 	if (vstor_packet->operation != VSTOR_OPERATION_COMPLETE_IO ||
895 	    vstor_packet->status != 0)
896 		goto cleanup;
897 
898 
899 	/* reuse the packet for version range supported */
900 	memset(vstor_packet, 0, sizeof(struct vstor_packet));
901 	vstor_packet->operation = VSTOR_OPERATION_QUERY_PROTOCOL_VERSION;
902 	vstor_packet->flags = REQUEST_COMPLETION_FLAG;
903 
904 	vstor_packet->version.major_minor =
905 		storvsc_get_version(vmstor_current_major, vmstor_current_minor);
906 
907 	/*
908 	 * The revision number is only used in Windows; set it to 0.
909 	 */
910 	vstor_packet->version.revision = 0;
911 
912 	ret = vmbus_sendpacket(device->channel, vstor_packet,
913 			       (sizeof(struct vstor_packet) -
914 				vmscsi_size_delta),
915 			       (unsigned long)request,
916 			       VM_PKT_DATA_INBAND,
917 			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
918 	if (ret != 0)
919 		goto cleanup;
920 
921 	t = wait_for_completion_timeout(&request->wait_event, 5*HZ);
922 	if (t == 0) {
923 		ret = -ETIMEDOUT;
924 		goto cleanup;
925 	}
926 
927 	if (vstor_packet->operation != VSTOR_OPERATION_COMPLETE_IO ||
928 	    vstor_packet->status != 0)
929 		goto cleanup;
930 
931 
932 	memset(vstor_packet, 0, sizeof(struct vstor_packet));
933 	vstor_packet->operation = VSTOR_OPERATION_QUERY_PROPERTIES;
934 	vstor_packet->flags = REQUEST_COMPLETION_FLAG;
935 
936 	ret = vmbus_sendpacket(device->channel, vstor_packet,
937 			       (sizeof(struct vstor_packet) -
938 				vmscsi_size_delta),
939 			       (unsigned long)request,
940 			       VM_PKT_DATA_INBAND,
941 			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
942 
943 	if (ret != 0)
944 		goto cleanup;
945 
946 	t = wait_for_completion_timeout(&request->wait_event, 5*HZ);
947 	if (t == 0) {
948 		ret = -ETIMEDOUT;
949 		goto cleanup;
950 	}
951 
952 	if (vstor_packet->operation != VSTOR_OPERATION_COMPLETE_IO ||
953 	    vstor_packet->status != 0)
954 		goto cleanup;
955 
956 	/*
957 	 * Check to see if multi-channel support is there.
958 	 * Hosts that implement protocol version of 5.1 and above
959 	 * support multi-channel.
960 	 */
961 	max_chns = vstor_packet->storage_channel_properties.max_channel_cnt;
962 	if ((vmbus_proto_version != VERSION_WIN7) &&
963 	   (vmbus_proto_version != VERSION_WS2008))  {
964 		if (vstor_packet->storage_channel_properties.flags &
965 		    STORAGE_CHANNEL_SUPPORTS_MULTI_CHANNEL)
966 			process_sub_channels = true;
967 	}
968 
969 	memset(vstor_packet, 0, sizeof(struct vstor_packet));
970 	vstor_packet->operation = VSTOR_OPERATION_END_INITIALIZATION;
971 	vstor_packet->flags = REQUEST_COMPLETION_FLAG;
972 
973 	ret = vmbus_sendpacket(device->channel, vstor_packet,
974 			       (sizeof(struct vstor_packet) -
975 				vmscsi_size_delta),
976 			       (unsigned long)request,
977 			       VM_PKT_DATA_INBAND,
978 			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
979 
980 	if (ret != 0)
981 		goto cleanup;
982 
983 	t = wait_for_completion_timeout(&request->wait_event, 5*HZ);
984 	if (t == 0) {
985 		ret = -ETIMEDOUT;
986 		goto cleanup;
987 	}
988 
989 	if (vstor_packet->operation != VSTOR_OPERATION_COMPLETE_IO ||
990 	    vstor_packet->status != 0)
991 		goto cleanup;
992 
993 	if (process_sub_channels)
994 		handle_multichannel_storage(device, max_chns);
995 
996 
997 cleanup:
998 	return ret;
999 }
1000 
1001 static void storvsc_handle_error(struct vmscsi_request *vm_srb,
1002 				struct scsi_cmnd *scmnd,
1003 				struct Scsi_Host *host,
1004 				u8 asc, u8 ascq)
1005 {
1006 	struct storvsc_scan_work *wrk;
1007 	void (*process_err_fn)(struct work_struct *work);
1008 	bool do_work = false;
1009 
1010 	switch (vm_srb->srb_status) {
1011 	case SRB_STATUS_ERROR:
1012 		/*
1013 		 * If there is an error; offline the device since all
1014 		 * error recovery strategies would have already been
1015 		 * deployed on the host side. However, if the command
1016 		 * were a pass-through command deal with it appropriately.
1017 		 */
1018 		switch (scmnd->cmnd[0]) {
1019 		case ATA_16:
1020 		case ATA_12:
1021 			set_host_byte(scmnd, DID_PASSTHROUGH);
1022 			break;
1023 		/*
1024 		 * On Some Windows hosts TEST_UNIT_READY command can return
1025 		 * SRB_STATUS_ERROR, let the upper level code deal with it
1026 		 * based on the sense information.
1027 		 */
1028 		case TEST_UNIT_READY:
1029 			break;
1030 		default:
1031 			set_host_byte(scmnd, DID_TARGET_FAILURE);
1032 		}
1033 		break;
1034 	case SRB_STATUS_INVALID_LUN:
1035 		do_work = true;
1036 		process_err_fn = storvsc_remove_lun;
1037 		break;
1038 	case (SRB_STATUS_ABORTED | SRB_STATUS_AUTOSENSE_VALID):
1039 		if ((asc == 0x2a) && (ascq == 0x9)) {
1040 			do_work = true;
1041 			process_err_fn = storvsc_device_scan;
1042 			/*
1043 			 * Retry the I/O that trigerred this.
1044 			 */
1045 			set_host_byte(scmnd, DID_REQUEUE);
1046 		}
1047 		break;
1048 	}
1049 
1050 	if (!do_work)
1051 		return;
1052 
1053 	/*
1054 	 * We need to schedule work to process this error; schedule it.
1055 	 */
1056 	wrk = kmalloc(sizeof(struct storvsc_scan_work), GFP_ATOMIC);
1057 	if (!wrk) {
1058 		set_host_byte(scmnd, DID_TARGET_FAILURE);
1059 		return;
1060 	}
1061 
1062 	wrk->host = host;
1063 	wrk->lun = vm_srb->lun;
1064 	INIT_WORK(&wrk->work, process_err_fn);
1065 	schedule_work(&wrk->work);
1066 }
1067 
1068 
1069 static void storvsc_command_completion(struct storvsc_cmd_request *cmd_request)
1070 {
1071 	struct scsi_cmnd *scmnd = cmd_request->cmd;
1072 	struct hv_host_device *host_dev = shost_priv(scmnd->device->host);
1073 	void (*scsi_done_fn)(struct scsi_cmnd *);
1074 	struct scsi_sense_hdr sense_hdr;
1075 	struct vmscsi_request *vm_srb;
1076 	struct stor_mem_pools *memp = scmnd->device->hostdata;
1077 	struct Scsi_Host *host;
1078 	struct storvsc_device *stor_dev;
1079 	struct hv_device *dev = host_dev->dev;
1080 
1081 	stor_dev = get_in_stor_device(dev);
1082 	host = stor_dev->host;
1083 
1084 	vm_srb = &cmd_request->vstor_packet.vm_srb;
1085 	if (cmd_request->bounce_sgl_count) {
1086 		if (vm_srb->data_in == READ_TYPE)
1087 			copy_from_bounce_buffer(scsi_sglist(scmnd),
1088 					cmd_request->bounce_sgl,
1089 					scsi_sg_count(scmnd),
1090 					cmd_request->bounce_sgl_count);
1091 		destroy_bounce_buffer(cmd_request->bounce_sgl,
1092 					cmd_request->bounce_sgl_count);
1093 	}
1094 
1095 	scmnd->result = vm_srb->scsi_status;
1096 
1097 	if (scmnd->result) {
1098 		if (scsi_normalize_sense(scmnd->sense_buffer,
1099 				SCSI_SENSE_BUFFERSIZE, &sense_hdr))
1100 			scsi_print_sense_hdr(scmnd->device, "storvsc",
1101 					     &sense_hdr);
1102 	}
1103 
1104 	if (vm_srb->srb_status != SRB_STATUS_SUCCESS)
1105 		storvsc_handle_error(vm_srb, scmnd, host, sense_hdr.asc,
1106 					 sense_hdr.ascq);
1107 
1108 	scsi_set_resid(scmnd,
1109 		cmd_request->data_buffer.len -
1110 		vm_srb->data_transfer_length);
1111 
1112 	scsi_done_fn = scmnd->scsi_done;
1113 
1114 	scmnd->host_scribble = NULL;
1115 	scmnd->scsi_done = NULL;
1116 
1117 	scsi_done_fn(scmnd);
1118 
1119 	mempool_free(cmd_request, memp->request_mempool);
1120 }
1121 
1122 static void storvsc_on_io_completion(struct hv_device *device,
1123 				  struct vstor_packet *vstor_packet,
1124 				  struct storvsc_cmd_request *request)
1125 {
1126 	struct storvsc_device *stor_device;
1127 	struct vstor_packet *stor_pkt;
1128 
1129 	stor_device = hv_get_drvdata(device);
1130 	stor_pkt = &request->vstor_packet;
1131 
1132 	/*
1133 	 * The current SCSI handling on the host side does
1134 	 * not correctly handle:
1135 	 * INQUIRY command with page code parameter set to 0x80
1136 	 * MODE_SENSE command with cmd[2] == 0x1c
1137 	 *
1138 	 * Setup srb and scsi status so this won't be fatal.
1139 	 * We do this so we can distinguish truly fatal failues
1140 	 * (srb status == 0x4) and off-line the device in that case.
1141 	 */
1142 
1143 	if ((stor_pkt->vm_srb.cdb[0] == INQUIRY) ||
1144 	   (stor_pkt->vm_srb.cdb[0] == MODE_SENSE)) {
1145 		vstor_packet->vm_srb.scsi_status = 0;
1146 		vstor_packet->vm_srb.srb_status = SRB_STATUS_SUCCESS;
1147 	}
1148 
1149 
1150 	/* Copy over the status...etc */
1151 	stor_pkt->vm_srb.scsi_status = vstor_packet->vm_srb.scsi_status;
1152 	stor_pkt->vm_srb.srb_status = vstor_packet->vm_srb.srb_status;
1153 	stor_pkt->vm_srb.sense_info_length =
1154 	vstor_packet->vm_srb.sense_info_length;
1155 
1156 
1157 	if ((vstor_packet->vm_srb.scsi_status & 0xFF) == 0x02) {
1158 		/* CHECK_CONDITION */
1159 		if (vstor_packet->vm_srb.srb_status &
1160 			SRB_STATUS_AUTOSENSE_VALID) {
1161 			/* autosense data available */
1162 
1163 			memcpy(request->sense_buffer,
1164 			       vstor_packet->vm_srb.sense_data,
1165 			       vstor_packet->vm_srb.sense_info_length);
1166 
1167 		}
1168 	}
1169 
1170 	stor_pkt->vm_srb.data_transfer_length =
1171 	vstor_packet->vm_srb.data_transfer_length;
1172 
1173 	storvsc_command_completion(request);
1174 
1175 	if (atomic_dec_and_test(&stor_device->num_outstanding_req) &&
1176 		stor_device->drain_notify)
1177 		wake_up(&stor_device->waiting_to_drain);
1178 
1179 
1180 }
1181 
1182 static void storvsc_on_receive(struct hv_device *device,
1183 			     struct vstor_packet *vstor_packet,
1184 			     struct storvsc_cmd_request *request)
1185 {
1186 	struct storvsc_scan_work *work;
1187 	struct storvsc_device *stor_device;
1188 
1189 	switch (vstor_packet->operation) {
1190 	case VSTOR_OPERATION_COMPLETE_IO:
1191 		storvsc_on_io_completion(device, vstor_packet, request);
1192 		break;
1193 
1194 	case VSTOR_OPERATION_REMOVE_DEVICE:
1195 	case VSTOR_OPERATION_ENUMERATE_BUS:
1196 		stor_device = get_in_stor_device(device);
1197 		work = kmalloc(sizeof(struct storvsc_scan_work), GFP_ATOMIC);
1198 		if (!work)
1199 			return;
1200 
1201 		INIT_WORK(&work->work, storvsc_bus_scan);
1202 		work->host = stor_device->host;
1203 		schedule_work(&work->work);
1204 		break;
1205 
1206 	default:
1207 		break;
1208 	}
1209 }
1210 
1211 static void storvsc_on_channel_callback(void *context)
1212 {
1213 	struct vmbus_channel *channel = (struct vmbus_channel *)context;
1214 	struct hv_device *device;
1215 	struct storvsc_device *stor_device;
1216 	u32 bytes_recvd;
1217 	u64 request_id;
1218 	unsigned char packet[ALIGN(sizeof(struct vstor_packet), 8)];
1219 	struct storvsc_cmd_request *request;
1220 	int ret;
1221 
1222 	if (channel->primary_channel != NULL)
1223 		device = channel->primary_channel->device_obj;
1224 	else
1225 		device = channel->device_obj;
1226 
1227 	stor_device = get_in_stor_device(device);
1228 	if (!stor_device)
1229 		return;
1230 
1231 	do {
1232 		ret = vmbus_recvpacket(channel, packet,
1233 				       ALIGN((sizeof(struct vstor_packet) -
1234 					     vmscsi_size_delta), 8),
1235 				       &bytes_recvd, &request_id);
1236 		if (ret == 0 && bytes_recvd > 0) {
1237 
1238 			request = (struct storvsc_cmd_request *)
1239 					(unsigned long)request_id;
1240 
1241 			if ((request == &stor_device->init_request) ||
1242 			    (request == &stor_device->reset_request)) {
1243 
1244 				memcpy(&request->vstor_packet, packet,
1245 				       (sizeof(struct vstor_packet) -
1246 					vmscsi_size_delta));
1247 				complete(&request->wait_event);
1248 			} else {
1249 				storvsc_on_receive(device,
1250 						(struct vstor_packet *)packet,
1251 						request);
1252 			}
1253 		} else {
1254 			break;
1255 		}
1256 	} while (1);
1257 
1258 	return;
1259 }
1260 
1261 static int storvsc_connect_to_vsp(struct hv_device *device, u32 ring_size)
1262 {
1263 	struct vmstorage_channel_properties props;
1264 	int ret;
1265 
1266 	memset(&props, 0, sizeof(struct vmstorage_channel_properties));
1267 
1268 	ret = vmbus_open(device->channel,
1269 			 ring_size,
1270 			 ring_size,
1271 			 (void *)&props,
1272 			 sizeof(struct vmstorage_channel_properties),
1273 			 storvsc_on_channel_callback, device->channel);
1274 
1275 	if (ret != 0)
1276 		return ret;
1277 
1278 	ret = storvsc_channel_init(device);
1279 
1280 	return ret;
1281 }
1282 
1283 static int storvsc_dev_remove(struct hv_device *device)
1284 {
1285 	struct storvsc_device *stor_device;
1286 	unsigned long flags;
1287 
1288 	stor_device = hv_get_drvdata(device);
1289 
1290 	spin_lock_irqsave(&device->channel->inbound_lock, flags);
1291 	stor_device->destroy = true;
1292 	spin_unlock_irqrestore(&device->channel->inbound_lock, flags);
1293 
1294 	/*
1295 	 * At this point, all outbound traffic should be disable. We
1296 	 * only allow inbound traffic (responses) to proceed so that
1297 	 * outstanding requests can be completed.
1298 	 */
1299 
1300 	storvsc_wait_to_drain(stor_device);
1301 
1302 	/*
1303 	 * Since we have already drained, we don't need to busy wait
1304 	 * as was done in final_release_stor_device()
1305 	 * Note that we cannot set the ext pointer to NULL until
1306 	 * we have drained - to drain the outgoing packets, we need to
1307 	 * allow incoming packets.
1308 	 */
1309 	spin_lock_irqsave(&device->channel->inbound_lock, flags);
1310 	hv_set_drvdata(device, NULL);
1311 	spin_unlock_irqrestore(&device->channel->inbound_lock, flags);
1312 
1313 	/* Close the channel */
1314 	vmbus_close(device->channel);
1315 
1316 	kfree(stor_device);
1317 	return 0;
1318 }
1319 
1320 static int storvsc_do_io(struct hv_device *device,
1321 			      struct storvsc_cmd_request *request)
1322 {
1323 	struct storvsc_device *stor_device;
1324 	struct vstor_packet *vstor_packet;
1325 	struct vmbus_channel *outgoing_channel;
1326 	int ret = 0;
1327 
1328 	vstor_packet = &request->vstor_packet;
1329 	stor_device = get_out_stor_device(device);
1330 
1331 	if (!stor_device)
1332 		return -ENODEV;
1333 
1334 
1335 	request->device  = device;
1336 	/*
1337 	 * Select an an appropriate channel to send the request out.
1338 	 */
1339 
1340 	outgoing_channel = vmbus_get_outgoing_channel(device->channel);
1341 
1342 
1343 	vstor_packet->flags |= REQUEST_COMPLETION_FLAG;
1344 
1345 	vstor_packet->vm_srb.length = (sizeof(struct vmscsi_request) -
1346 					vmscsi_size_delta);
1347 
1348 
1349 	vstor_packet->vm_srb.sense_info_length = sense_buffer_size;
1350 
1351 
1352 	vstor_packet->vm_srb.data_transfer_length =
1353 	request->data_buffer.len;
1354 
1355 	vstor_packet->operation = VSTOR_OPERATION_EXECUTE_SRB;
1356 
1357 	if (request->data_buffer.len) {
1358 		ret = vmbus_sendpacket_multipagebuffer(outgoing_channel,
1359 				&request->data_buffer,
1360 				vstor_packet,
1361 				(sizeof(struct vstor_packet) -
1362 				vmscsi_size_delta),
1363 				(unsigned long)request);
1364 	} else {
1365 		ret = vmbus_sendpacket(device->channel, vstor_packet,
1366 			       (sizeof(struct vstor_packet) -
1367 				vmscsi_size_delta),
1368 			       (unsigned long)request,
1369 			       VM_PKT_DATA_INBAND,
1370 			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
1371 	}
1372 
1373 	if (ret != 0)
1374 		return ret;
1375 
1376 	atomic_inc(&stor_device->num_outstanding_req);
1377 
1378 	return ret;
1379 }
1380 
1381 static int storvsc_device_alloc(struct scsi_device *sdevice)
1382 {
1383 	struct stor_mem_pools *memp;
1384 	int number = STORVSC_MIN_BUF_NR;
1385 
1386 	memp = kzalloc(sizeof(struct stor_mem_pools), GFP_KERNEL);
1387 	if (!memp)
1388 		return -ENOMEM;
1389 
1390 	memp->request_pool =
1391 		kmem_cache_create(dev_name(&sdevice->sdev_dev),
1392 				sizeof(struct storvsc_cmd_request), 0,
1393 				SLAB_HWCACHE_ALIGN, NULL);
1394 
1395 	if (!memp->request_pool)
1396 		goto err0;
1397 
1398 	memp->request_mempool = mempool_create(number, mempool_alloc_slab,
1399 						mempool_free_slab,
1400 						memp->request_pool);
1401 
1402 	if (!memp->request_mempool)
1403 		goto err1;
1404 
1405 	sdevice->hostdata = memp;
1406 
1407 	return 0;
1408 
1409 err1:
1410 	kmem_cache_destroy(memp->request_pool);
1411 
1412 err0:
1413 	kfree(memp);
1414 	return -ENOMEM;
1415 }
1416 
1417 static void storvsc_device_destroy(struct scsi_device *sdevice)
1418 {
1419 	struct stor_mem_pools *memp = sdevice->hostdata;
1420 
1421 	if (!memp)
1422 		return;
1423 
1424 	mempool_destroy(memp->request_mempool);
1425 	kmem_cache_destroy(memp->request_pool);
1426 	kfree(memp);
1427 	sdevice->hostdata = NULL;
1428 }
1429 
1430 static int storvsc_device_configure(struct scsi_device *sdevice)
1431 {
1432 	scsi_change_queue_depth(sdevice, STORVSC_MAX_IO_REQUESTS);
1433 
1434 	blk_queue_max_segment_size(sdevice->request_queue, PAGE_SIZE);
1435 
1436 	blk_queue_bounce_limit(sdevice->request_queue, BLK_BOUNCE_ANY);
1437 
1438 	blk_queue_rq_timeout(sdevice->request_queue, (storvsc_timeout * HZ));
1439 
1440 	sdevice->no_write_same = 1;
1441 
1442 	/*
1443 	 * Add blist flags to permit the reading of the VPD pages even when
1444 	 * the target may claim SPC-2 compliance. MSFT targets currently
1445 	 * claim SPC-2 compliance while they implement post SPC-2 features.
1446 	 * With this patch we can correctly handle WRITE_SAME_16 issues.
1447 	 */
1448 	sdevice->sdev_bflags |= msft_blist_flags;
1449 
1450 	return 0;
1451 }
1452 
1453 static int storvsc_get_chs(struct scsi_device *sdev, struct block_device * bdev,
1454 			   sector_t capacity, int *info)
1455 {
1456 	sector_t nsect = capacity;
1457 	sector_t cylinders = nsect;
1458 	int heads, sectors_pt;
1459 
1460 	/*
1461 	 * We are making up these values; let us keep it simple.
1462 	 */
1463 	heads = 0xff;
1464 	sectors_pt = 0x3f;      /* Sectors per track */
1465 	sector_div(cylinders, heads * sectors_pt);
1466 	if ((sector_t)(cylinders + 1) * heads * sectors_pt < nsect)
1467 		cylinders = 0xffff;
1468 
1469 	info[0] = heads;
1470 	info[1] = sectors_pt;
1471 	info[2] = (int)cylinders;
1472 
1473 	return 0;
1474 }
1475 
1476 static int storvsc_host_reset_handler(struct scsi_cmnd *scmnd)
1477 {
1478 	struct hv_host_device *host_dev = shost_priv(scmnd->device->host);
1479 	struct hv_device *device = host_dev->dev;
1480 
1481 	struct storvsc_device *stor_device;
1482 	struct storvsc_cmd_request *request;
1483 	struct vstor_packet *vstor_packet;
1484 	int ret, t;
1485 
1486 
1487 	stor_device = get_out_stor_device(device);
1488 	if (!stor_device)
1489 		return FAILED;
1490 
1491 	request = &stor_device->reset_request;
1492 	vstor_packet = &request->vstor_packet;
1493 
1494 	init_completion(&request->wait_event);
1495 
1496 	vstor_packet->operation = VSTOR_OPERATION_RESET_BUS;
1497 	vstor_packet->flags = REQUEST_COMPLETION_FLAG;
1498 	vstor_packet->vm_srb.path_id = stor_device->path_id;
1499 
1500 	ret = vmbus_sendpacket(device->channel, vstor_packet,
1501 			       (sizeof(struct vstor_packet) -
1502 				vmscsi_size_delta),
1503 			       (unsigned long)&stor_device->reset_request,
1504 			       VM_PKT_DATA_INBAND,
1505 			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
1506 	if (ret != 0)
1507 		return FAILED;
1508 
1509 	t = wait_for_completion_timeout(&request->wait_event, 5*HZ);
1510 	if (t == 0)
1511 		return TIMEOUT_ERROR;
1512 
1513 
1514 	/*
1515 	 * At this point, all outstanding requests in the adapter
1516 	 * should have been flushed out and return to us
1517 	 * There is a potential race here where the host may be in
1518 	 * the process of responding when we return from here.
1519 	 * Just wait for all in-transit packets to be accounted for
1520 	 * before we return from here.
1521 	 */
1522 	storvsc_wait_to_drain(stor_device);
1523 
1524 	return SUCCESS;
1525 }
1526 
1527 /*
1528  * The host guarantees to respond to each command, although I/O latencies might
1529  * be unbounded on Azure.  Reset the timer unconditionally to give the host a
1530  * chance to perform EH.
1531  */
1532 static enum blk_eh_timer_return storvsc_eh_timed_out(struct scsi_cmnd *scmnd)
1533 {
1534 	return BLK_EH_RESET_TIMER;
1535 }
1536 
1537 static bool storvsc_scsi_cmd_ok(struct scsi_cmnd *scmnd)
1538 {
1539 	bool allowed = true;
1540 	u8 scsi_op = scmnd->cmnd[0];
1541 
1542 	switch (scsi_op) {
1543 	/* the host does not handle WRITE_SAME, log accident usage */
1544 	case WRITE_SAME:
1545 	/*
1546 	 * smartd sends this command and the host does not handle
1547 	 * this. So, don't send it.
1548 	 */
1549 	case SET_WINDOW:
1550 		scmnd->result = ILLEGAL_REQUEST << 16;
1551 		allowed = false;
1552 		break;
1553 	default:
1554 		break;
1555 	}
1556 	return allowed;
1557 }
1558 
1559 static int storvsc_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *scmnd)
1560 {
1561 	int ret;
1562 	struct hv_host_device *host_dev = shost_priv(host);
1563 	struct hv_device *dev = host_dev->dev;
1564 	struct storvsc_cmd_request *cmd_request;
1565 	unsigned int request_size = 0;
1566 	int i;
1567 	struct scatterlist *sgl;
1568 	unsigned int sg_count = 0;
1569 	struct vmscsi_request *vm_srb;
1570 	struct stor_mem_pools *memp = scmnd->device->hostdata;
1571 
1572 	if (vmstor_current_major <= VMSTOR_WIN8_MAJOR) {
1573 		/*
1574 		 * On legacy hosts filter unimplemented commands.
1575 		 * Future hosts are expected to correctly handle
1576 		 * unsupported commands. Furthermore, it is
1577 		 * possible that some of the currently
1578 		 * unsupported commands maybe supported in
1579 		 * future versions of the host.
1580 		 */
1581 		if (!storvsc_scsi_cmd_ok(scmnd)) {
1582 			scmnd->scsi_done(scmnd);
1583 			return 0;
1584 		}
1585 	}
1586 
1587 	request_size = sizeof(struct storvsc_cmd_request);
1588 
1589 	cmd_request = mempool_alloc(memp->request_mempool,
1590 				       GFP_ATOMIC);
1591 
1592 	/*
1593 	 * We might be invoked in an interrupt context; hence
1594 	 * mempool_alloc() can fail.
1595 	 */
1596 	if (!cmd_request)
1597 		return SCSI_MLQUEUE_DEVICE_BUSY;
1598 
1599 	memset(cmd_request, 0, sizeof(struct storvsc_cmd_request));
1600 
1601 	/* Setup the cmd request */
1602 	cmd_request->cmd = scmnd;
1603 
1604 	scmnd->host_scribble = (unsigned char *)cmd_request;
1605 
1606 	vm_srb = &cmd_request->vstor_packet.vm_srb;
1607 	vm_srb->win8_extension.time_out_value = 60;
1608 
1609 	vm_srb->win8_extension.srb_flags |=
1610 		(SRB_FLAGS_QUEUE_ACTION_ENABLE |
1611 		SRB_FLAGS_DISABLE_SYNCH_TRANSFER);
1612 
1613 	/* Build the SRB */
1614 	switch (scmnd->sc_data_direction) {
1615 	case DMA_TO_DEVICE:
1616 		vm_srb->data_in = WRITE_TYPE;
1617 		vm_srb->win8_extension.srb_flags |= SRB_FLAGS_DATA_OUT;
1618 		break;
1619 	case DMA_FROM_DEVICE:
1620 		vm_srb->data_in = READ_TYPE;
1621 		vm_srb->win8_extension.srb_flags |= SRB_FLAGS_DATA_IN;
1622 		break;
1623 	default:
1624 		vm_srb->data_in = UNKNOWN_TYPE;
1625 		vm_srb->win8_extension.srb_flags |= (SRB_FLAGS_DATA_IN |
1626 						     SRB_FLAGS_DATA_OUT);
1627 		break;
1628 	}
1629 
1630 
1631 	vm_srb->port_number = host_dev->port;
1632 	vm_srb->path_id = scmnd->device->channel;
1633 	vm_srb->target_id = scmnd->device->id;
1634 	vm_srb->lun = scmnd->device->lun;
1635 
1636 	vm_srb->cdb_length = scmnd->cmd_len;
1637 
1638 	memcpy(vm_srb->cdb, scmnd->cmnd, vm_srb->cdb_length);
1639 
1640 	cmd_request->sense_buffer = scmnd->sense_buffer;
1641 
1642 
1643 	cmd_request->data_buffer.len = scsi_bufflen(scmnd);
1644 	if (scsi_sg_count(scmnd)) {
1645 		sgl = (struct scatterlist *)scsi_sglist(scmnd);
1646 		sg_count = scsi_sg_count(scmnd);
1647 
1648 		/* check if we need to bounce the sgl */
1649 		if (do_bounce_buffer(sgl, scsi_sg_count(scmnd)) != -1) {
1650 			cmd_request->bounce_sgl =
1651 				create_bounce_buffer(sgl, scsi_sg_count(scmnd),
1652 						     scsi_bufflen(scmnd),
1653 						     vm_srb->data_in);
1654 			if (!cmd_request->bounce_sgl) {
1655 				ret = SCSI_MLQUEUE_HOST_BUSY;
1656 				goto queue_error;
1657 			}
1658 
1659 			cmd_request->bounce_sgl_count =
1660 				ALIGN(scsi_bufflen(scmnd), PAGE_SIZE) >>
1661 					PAGE_SHIFT;
1662 
1663 			if (vm_srb->data_in == WRITE_TYPE)
1664 				copy_to_bounce_buffer(sgl,
1665 					cmd_request->bounce_sgl,
1666 					scsi_sg_count(scmnd));
1667 
1668 			sgl = cmd_request->bounce_sgl;
1669 			sg_count = cmd_request->bounce_sgl_count;
1670 		}
1671 
1672 		cmd_request->data_buffer.offset = sgl[0].offset;
1673 
1674 		for (i = 0; i < sg_count; i++)
1675 			cmd_request->data_buffer.pfn_array[i] =
1676 				page_to_pfn(sg_page((&sgl[i])));
1677 
1678 	} else if (scsi_sglist(scmnd)) {
1679 		cmd_request->data_buffer.offset =
1680 			virt_to_phys(scsi_sglist(scmnd)) & (PAGE_SIZE-1);
1681 		cmd_request->data_buffer.pfn_array[0] =
1682 			virt_to_phys(scsi_sglist(scmnd)) >> PAGE_SHIFT;
1683 	}
1684 
1685 	/* Invokes the vsc to start an IO */
1686 	ret = storvsc_do_io(dev, cmd_request);
1687 
1688 	if (ret == -EAGAIN) {
1689 		/* no more space */
1690 
1691 		if (cmd_request->bounce_sgl_count)
1692 			destroy_bounce_buffer(cmd_request->bounce_sgl,
1693 					cmd_request->bounce_sgl_count);
1694 
1695 		ret = SCSI_MLQUEUE_DEVICE_BUSY;
1696 		goto queue_error;
1697 	}
1698 
1699 	return 0;
1700 
1701 queue_error:
1702 	mempool_free(cmd_request, memp->request_mempool);
1703 	scmnd->host_scribble = NULL;
1704 	return ret;
1705 }
1706 
1707 static struct scsi_host_template scsi_driver = {
1708 	.module	=		THIS_MODULE,
1709 	.name =			"storvsc_host_t",
1710 	.bios_param =		storvsc_get_chs,
1711 	.queuecommand =		storvsc_queuecommand,
1712 	.eh_host_reset_handler =	storvsc_host_reset_handler,
1713 	.eh_timed_out =		storvsc_eh_timed_out,
1714 	.slave_alloc =		storvsc_device_alloc,
1715 	.slave_destroy =	storvsc_device_destroy,
1716 	.slave_configure =	storvsc_device_configure,
1717 	.cmd_per_lun =		255,
1718 	.can_queue =		STORVSC_MAX_IO_REQUESTS*STORVSC_MAX_TARGETS,
1719 	.this_id =		-1,
1720 	/* no use setting to 0 since ll_blk_rw reset it to 1 */
1721 	/* currently 32 */
1722 	.sg_tablesize =		MAX_MULTIPAGE_BUFFER_COUNT,
1723 	.use_clustering =	DISABLE_CLUSTERING,
1724 	/* Make sure we dont get a sg segment crosses a page boundary */
1725 	.dma_boundary =		PAGE_SIZE-1,
1726 	.no_write_same =	1,
1727 };
1728 
1729 enum {
1730 	SCSI_GUID,
1731 	IDE_GUID,
1732 	SFC_GUID,
1733 };
1734 
1735 static const struct hv_vmbus_device_id id_table[] = {
1736 	/* SCSI guid */
1737 	{ HV_SCSI_GUID,
1738 	  .driver_data = SCSI_GUID
1739 	},
1740 	/* IDE guid */
1741 	{ HV_IDE_GUID,
1742 	  .driver_data = IDE_GUID
1743 	},
1744 	/* Fibre Channel GUID */
1745 	{
1746 	  HV_SYNTHFC_GUID,
1747 	  .driver_data = SFC_GUID
1748 	},
1749 	{ },
1750 };
1751 
1752 MODULE_DEVICE_TABLE(vmbus, id_table);
1753 
1754 static int storvsc_probe(struct hv_device *device,
1755 			const struct hv_vmbus_device_id *dev_id)
1756 {
1757 	int ret;
1758 	struct Scsi_Host *host;
1759 	struct hv_host_device *host_dev;
1760 	bool dev_is_ide = ((dev_id->driver_data == IDE_GUID) ? true : false);
1761 	int target = 0;
1762 	struct storvsc_device *stor_device;
1763 
1764 	/*
1765 	 * Based on the windows host we are running on,
1766 	 * set state to properly communicate with the host.
1767 	 */
1768 
1769 	switch (vmbus_proto_version) {
1770 	case VERSION_WS2008:
1771 	case VERSION_WIN7:
1772 		sense_buffer_size = PRE_WIN8_STORVSC_SENSE_BUFFER_SIZE;
1773 		vmscsi_size_delta = sizeof(struct vmscsi_win8_extension);
1774 		vmstor_current_major = VMSTOR_WIN7_MAJOR;
1775 		vmstor_current_minor = VMSTOR_WIN7_MINOR;
1776 		break;
1777 	default:
1778 		sense_buffer_size = POST_WIN7_STORVSC_SENSE_BUFFER_SIZE;
1779 		vmscsi_size_delta = 0;
1780 		vmstor_current_major = VMSTOR_WIN8_MAJOR;
1781 		vmstor_current_minor = VMSTOR_WIN8_MINOR;
1782 		break;
1783 	}
1784 
1785 	if (dev_id->driver_data == SFC_GUID)
1786 		scsi_driver.can_queue = (STORVSC_MAX_IO_REQUESTS *
1787 					 STORVSC_FC_MAX_TARGETS);
1788 	host = scsi_host_alloc(&scsi_driver,
1789 			       sizeof(struct hv_host_device));
1790 	if (!host)
1791 		return -ENOMEM;
1792 
1793 	host_dev = shost_priv(host);
1794 	memset(host_dev, 0, sizeof(struct hv_host_device));
1795 
1796 	host_dev->port = host->host_no;
1797 	host_dev->dev = device;
1798 
1799 
1800 	stor_device = kzalloc(sizeof(struct storvsc_device), GFP_KERNEL);
1801 	if (!stor_device) {
1802 		ret = -ENOMEM;
1803 		goto err_out0;
1804 	}
1805 
1806 	stor_device->destroy = false;
1807 	stor_device->open_sub_channel = false;
1808 	init_waitqueue_head(&stor_device->waiting_to_drain);
1809 	stor_device->device = device;
1810 	stor_device->host = host;
1811 	hv_set_drvdata(device, stor_device);
1812 
1813 	stor_device->port_number = host->host_no;
1814 	ret = storvsc_connect_to_vsp(device, storvsc_ringbuffer_size);
1815 	if (ret)
1816 		goto err_out1;
1817 
1818 	host_dev->path = stor_device->path_id;
1819 	host_dev->target = stor_device->target_id;
1820 
1821 	switch (dev_id->driver_data) {
1822 	case SFC_GUID:
1823 		host->max_lun = STORVSC_FC_MAX_LUNS_PER_TARGET;
1824 		host->max_id = STORVSC_FC_MAX_TARGETS;
1825 		host->max_channel = STORVSC_FC_MAX_CHANNELS - 1;
1826 		break;
1827 
1828 	case SCSI_GUID:
1829 		host->max_lun = STORVSC_MAX_LUNS_PER_TARGET;
1830 		host->max_id = STORVSC_MAX_TARGETS;
1831 		host->max_channel = STORVSC_MAX_CHANNELS - 1;
1832 		break;
1833 
1834 	default:
1835 		host->max_lun = STORVSC_IDE_MAX_LUNS_PER_TARGET;
1836 		host->max_id = STORVSC_IDE_MAX_TARGETS;
1837 		host->max_channel = STORVSC_IDE_MAX_CHANNELS - 1;
1838 		break;
1839 	}
1840 	/* max cmd length */
1841 	host->max_cmd_len = STORVSC_MAX_CMD_LEN;
1842 
1843 	/* Register the HBA and start the scsi bus scan */
1844 	ret = scsi_add_host(host, &device->device);
1845 	if (ret != 0)
1846 		goto err_out2;
1847 
1848 	if (!dev_is_ide) {
1849 		scsi_scan_host(host);
1850 	} else {
1851 		target = (device->dev_instance.b[5] << 8 |
1852 			 device->dev_instance.b[4]);
1853 		ret = scsi_add_device(host, 0, target, 0);
1854 		if (ret) {
1855 			scsi_remove_host(host);
1856 			goto err_out2;
1857 		}
1858 	}
1859 	return 0;
1860 
1861 err_out2:
1862 	/*
1863 	 * Once we have connected with the host, we would need to
1864 	 * to invoke storvsc_dev_remove() to rollback this state and
1865 	 * this call also frees up the stor_device; hence the jump around
1866 	 * err_out1 label.
1867 	 */
1868 	storvsc_dev_remove(device);
1869 	goto err_out0;
1870 
1871 err_out1:
1872 	kfree(stor_device);
1873 
1874 err_out0:
1875 	scsi_host_put(host);
1876 	return ret;
1877 }
1878 
1879 static int storvsc_remove(struct hv_device *dev)
1880 {
1881 	struct storvsc_device *stor_device = hv_get_drvdata(dev);
1882 	struct Scsi_Host *host = stor_device->host;
1883 
1884 	scsi_remove_host(host);
1885 	storvsc_dev_remove(dev);
1886 	scsi_host_put(host);
1887 
1888 	return 0;
1889 }
1890 
1891 static struct hv_driver storvsc_drv = {
1892 	.name = KBUILD_MODNAME,
1893 	.id_table = id_table,
1894 	.probe = storvsc_probe,
1895 	.remove = storvsc_remove,
1896 };
1897 
1898 static int __init storvsc_drv_init(void)
1899 {
1900 	u32 max_outstanding_req_per_channel;
1901 
1902 	/*
1903 	 * Divide the ring buffer data size (which is 1 page less
1904 	 * than the ring buffer size since that page is reserved for
1905 	 * the ring buffer indices) by the max request size (which is
1906 	 * vmbus_channel_packet_multipage_buffer + struct vstor_packet + u64)
1907 	 */
1908 	max_outstanding_req_per_channel =
1909 		((storvsc_ringbuffer_size - PAGE_SIZE) /
1910 		ALIGN(MAX_MULTIPAGE_BUFFER_PACKET +
1911 		sizeof(struct vstor_packet) + sizeof(u64) -
1912 		vmscsi_size_delta,
1913 		sizeof(u64)));
1914 
1915 	if (max_outstanding_req_per_channel <
1916 	    STORVSC_MAX_IO_REQUESTS)
1917 		return -EINVAL;
1918 
1919 	return vmbus_driver_register(&storvsc_drv);
1920 }
1921 
1922 static void __exit storvsc_drv_exit(void)
1923 {
1924 	vmbus_driver_unregister(&storvsc_drv);
1925 }
1926 
1927 MODULE_LICENSE("GPL");
1928 MODULE_DESCRIPTION("Microsoft Hyper-V virtual storage driver");
1929 module_init(storvsc_drv_init);
1930 module_exit(storvsc_drv_exit);
1931