xref: /openbmc/linux/drivers/scsi/storvsc_drv.c (revision 12eb4683)
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				200
330 
331 static void storvsc_on_channel_callback(void *context);
332 
333 /*
334  * In Hyper-V, each port/path/target maps to 1 scsi host adapter.  In
335  * reality, the path/target is not used (ie always set to 0) so our
336  * scsi host adapter essentially has 1 bus with 1 target that contains
337  * up to 256 luns.
338  */
339 #define STORVSC_MAX_LUNS_PER_TARGET			64
340 #define STORVSC_MAX_TARGETS				1
341 #define STORVSC_MAX_CHANNELS				1
342 
343 
344 
345 struct storvsc_cmd_request {
346 	struct list_head entry;
347 	struct scsi_cmnd *cmd;
348 
349 	unsigned int bounce_sgl_count;
350 	struct scatterlist *bounce_sgl;
351 
352 	struct hv_device *device;
353 
354 	/* Synchronize the request/response if needed */
355 	struct completion wait_event;
356 
357 	unsigned char *sense_buffer;
358 	struct hv_multipage_buffer data_buffer;
359 	struct vstor_packet vstor_packet;
360 };
361 
362 
363 /* A storvsc device is a device object that contains a vmbus channel */
364 struct storvsc_device {
365 	struct hv_device *device;
366 
367 	bool	 destroy;
368 	bool	 drain_notify;
369 	bool	 open_sub_channel;
370 	atomic_t num_outstanding_req;
371 	struct Scsi_Host *host;
372 
373 	wait_queue_head_t waiting_to_drain;
374 
375 	/*
376 	 * Each unique Port/Path/Target represents 1 channel ie scsi
377 	 * controller. In reality, the pathid, targetid is always 0
378 	 * and the port is set by us
379 	 */
380 	unsigned int port_number;
381 	unsigned char path_id;
382 	unsigned char target_id;
383 
384 	/* Used for vsc/vsp channel reset process */
385 	struct storvsc_cmd_request init_request;
386 	struct storvsc_cmd_request reset_request;
387 };
388 
389 struct stor_mem_pools {
390 	struct kmem_cache *request_pool;
391 	mempool_t *request_mempool;
392 };
393 
394 struct hv_host_device {
395 	struct hv_device *dev;
396 	unsigned int port;
397 	unsigned char path;
398 	unsigned char target;
399 };
400 
401 struct storvsc_scan_work {
402 	struct work_struct work;
403 	struct Scsi_Host *host;
404 	uint lun;
405 };
406 
407 static void storvsc_device_scan(struct work_struct *work)
408 {
409 	struct storvsc_scan_work *wrk;
410 	uint lun;
411 	struct scsi_device *sdev;
412 
413 	wrk = container_of(work, struct storvsc_scan_work, work);
414 	lun = wrk->lun;
415 
416 	sdev = scsi_device_lookup(wrk->host, 0, 0, lun);
417 	if (!sdev)
418 		goto done;
419 	scsi_rescan_device(&sdev->sdev_gendev);
420 	scsi_device_put(sdev);
421 
422 done:
423 	kfree(wrk);
424 }
425 
426 static void storvsc_bus_scan(struct work_struct *work)
427 {
428 	struct storvsc_scan_work *wrk;
429 	int id, order_id;
430 
431 	wrk = container_of(work, struct storvsc_scan_work, work);
432 	for (id = 0; id < wrk->host->max_id; ++id) {
433 		if (wrk->host->reverse_ordering)
434 			order_id = wrk->host->max_id - id - 1;
435 		else
436 			order_id = id;
437 
438 		scsi_scan_target(&wrk->host->shost_gendev, 0,
439 				order_id, SCAN_WILD_CARD, 1);
440 	}
441 	kfree(wrk);
442 }
443 
444 static void storvsc_remove_lun(struct work_struct *work)
445 {
446 	struct storvsc_scan_work *wrk;
447 	struct scsi_device *sdev;
448 
449 	wrk = container_of(work, struct storvsc_scan_work, work);
450 	if (!scsi_host_get(wrk->host))
451 		goto done;
452 
453 	sdev = scsi_device_lookup(wrk->host, 0, 0, wrk->lun);
454 
455 	if (sdev) {
456 		scsi_remove_device(sdev);
457 		scsi_device_put(sdev);
458 	}
459 	scsi_host_put(wrk->host);
460 
461 done:
462 	kfree(wrk);
463 }
464 
465 /*
466  * Major/minor macros.  Minor version is in LSB, meaning that earlier flat
467  * version numbers will be interpreted as "0.x" (i.e., 1 becomes 0.1).
468  */
469 
470 static inline u16 storvsc_get_version(u8 major, u8 minor)
471 {
472 	u16 version;
473 
474 	version = ((major << 8) | minor);
475 	return version;
476 }
477 
478 /*
479  * We can get incoming messages from the host that are not in response to
480  * messages that we have sent out. An example of this would be messages
481  * received by the guest to notify dynamic addition/removal of LUNs. To
482  * deal with potential race conditions where the driver may be in the
483  * midst of being unloaded when we might receive an unsolicited message
484  * from the host, we have implemented a mechanism to gurantee sequential
485  * consistency:
486  *
487  * 1) Once the device is marked as being destroyed, we will fail all
488  *    outgoing messages.
489  * 2) We permit incoming messages when the device is being destroyed,
490  *    only to properly account for messages already sent out.
491  */
492 
493 static inline struct storvsc_device *get_out_stor_device(
494 					struct hv_device *device)
495 {
496 	struct storvsc_device *stor_device;
497 
498 	stor_device = hv_get_drvdata(device);
499 
500 	if (stor_device && stor_device->destroy)
501 		stor_device = NULL;
502 
503 	return stor_device;
504 }
505 
506 
507 static inline void storvsc_wait_to_drain(struct storvsc_device *dev)
508 {
509 	dev->drain_notify = true;
510 	wait_event(dev->waiting_to_drain,
511 		   atomic_read(&dev->num_outstanding_req) == 0);
512 	dev->drain_notify = false;
513 }
514 
515 static inline struct storvsc_device *get_in_stor_device(
516 					struct hv_device *device)
517 {
518 	struct storvsc_device *stor_device;
519 
520 	stor_device = hv_get_drvdata(device);
521 
522 	if (!stor_device)
523 		goto get_in_err;
524 
525 	/*
526 	 * If the device is being destroyed; allow incoming
527 	 * traffic only to cleanup outstanding requests.
528 	 */
529 
530 	if (stor_device->destroy  &&
531 		(atomic_read(&stor_device->num_outstanding_req) == 0))
532 		stor_device = NULL;
533 
534 get_in_err:
535 	return stor_device;
536 
537 }
538 
539 static void destroy_bounce_buffer(struct scatterlist *sgl,
540 				  unsigned int sg_count)
541 {
542 	int i;
543 	struct page *page_buf;
544 
545 	for (i = 0; i < sg_count; i++) {
546 		page_buf = sg_page((&sgl[i]));
547 		if (page_buf != NULL)
548 			__free_page(page_buf);
549 	}
550 
551 	kfree(sgl);
552 }
553 
554 static int do_bounce_buffer(struct scatterlist *sgl, unsigned int sg_count)
555 {
556 	int i;
557 
558 	/* No need to check */
559 	if (sg_count < 2)
560 		return -1;
561 
562 	/* We have at least 2 sg entries */
563 	for (i = 0; i < sg_count; i++) {
564 		if (i == 0) {
565 			/* make sure 1st one does not have hole */
566 			if (sgl[i].offset + sgl[i].length != PAGE_SIZE)
567 				return i;
568 		} else if (i == sg_count - 1) {
569 			/* make sure last one does not have hole */
570 			if (sgl[i].offset != 0)
571 				return i;
572 		} else {
573 			/* make sure no hole in the middle */
574 			if (sgl[i].length != PAGE_SIZE || sgl[i].offset != 0)
575 				return i;
576 		}
577 	}
578 	return -1;
579 }
580 
581 static struct scatterlist *create_bounce_buffer(struct scatterlist *sgl,
582 						unsigned int sg_count,
583 						unsigned int len,
584 						int write)
585 {
586 	int i;
587 	int num_pages;
588 	struct scatterlist *bounce_sgl;
589 	struct page *page_buf;
590 	unsigned int buf_len = ((write == WRITE_TYPE) ? 0 : PAGE_SIZE);
591 
592 	num_pages = ALIGN(len, PAGE_SIZE) >> PAGE_SHIFT;
593 
594 	bounce_sgl = kcalloc(num_pages, sizeof(struct scatterlist), GFP_ATOMIC);
595 	if (!bounce_sgl)
596 		return NULL;
597 
598 	sg_init_table(bounce_sgl, num_pages);
599 	for (i = 0; i < num_pages; i++) {
600 		page_buf = alloc_page(GFP_ATOMIC);
601 		if (!page_buf)
602 			goto cleanup;
603 		sg_set_page(&bounce_sgl[i], page_buf, buf_len, 0);
604 	}
605 
606 	return bounce_sgl;
607 
608 cleanup:
609 	destroy_bounce_buffer(bounce_sgl, num_pages);
610 	return NULL;
611 }
612 
613 /* Disgusting wrapper functions */
614 static inline unsigned long sg_kmap_atomic(struct scatterlist *sgl, int idx)
615 {
616 	void *addr = kmap_atomic(sg_page(sgl + idx));
617 	return (unsigned long)addr;
618 }
619 
620 static inline void sg_kunmap_atomic(unsigned long addr)
621 {
622 	kunmap_atomic((void *)addr);
623 }
624 
625 
626 /* Assume the original sgl has enough room */
627 static unsigned int copy_from_bounce_buffer(struct scatterlist *orig_sgl,
628 					    struct scatterlist *bounce_sgl,
629 					    unsigned int orig_sgl_count,
630 					    unsigned int bounce_sgl_count)
631 {
632 	int i;
633 	int j = 0;
634 	unsigned long src, dest;
635 	unsigned int srclen, destlen, copylen;
636 	unsigned int total_copied = 0;
637 	unsigned long bounce_addr = 0;
638 	unsigned long dest_addr = 0;
639 	unsigned long flags;
640 
641 	local_irq_save(flags);
642 
643 	for (i = 0; i < orig_sgl_count; i++) {
644 		dest_addr = sg_kmap_atomic(orig_sgl,i) + orig_sgl[i].offset;
645 		dest = dest_addr;
646 		destlen = orig_sgl[i].length;
647 
648 		if (bounce_addr == 0)
649 			bounce_addr = sg_kmap_atomic(bounce_sgl,j);
650 
651 		while (destlen) {
652 			src = bounce_addr + bounce_sgl[j].offset;
653 			srclen = bounce_sgl[j].length - bounce_sgl[j].offset;
654 
655 			copylen = min(srclen, destlen);
656 			memcpy((void *)dest, (void *)src, copylen);
657 
658 			total_copied += copylen;
659 			bounce_sgl[j].offset += copylen;
660 			destlen -= copylen;
661 			dest += copylen;
662 
663 			if (bounce_sgl[j].offset == bounce_sgl[j].length) {
664 				/* full */
665 				sg_kunmap_atomic(bounce_addr);
666 				j++;
667 
668 				/*
669 				 * It is possible that the number of elements
670 				 * in the bounce buffer may not be equal to
671 				 * the number of elements in the original
672 				 * scatter list. Handle this correctly.
673 				 */
674 
675 				if (j == bounce_sgl_count) {
676 					/*
677 					 * We are done; cleanup and return.
678 					 */
679 					sg_kunmap_atomic(dest_addr - orig_sgl[i].offset);
680 					local_irq_restore(flags);
681 					return total_copied;
682 				}
683 
684 				/* if we need to use another bounce buffer */
685 				if (destlen || i != orig_sgl_count - 1)
686 					bounce_addr = sg_kmap_atomic(bounce_sgl,j);
687 			} else if (destlen == 0 && i == orig_sgl_count - 1) {
688 				/* unmap the last bounce that is < PAGE_SIZE */
689 				sg_kunmap_atomic(bounce_addr);
690 			}
691 		}
692 
693 		sg_kunmap_atomic(dest_addr - orig_sgl[i].offset);
694 	}
695 
696 	local_irq_restore(flags);
697 
698 	return total_copied;
699 }
700 
701 /* Assume the bounce_sgl has enough room ie using the create_bounce_buffer() */
702 static unsigned int copy_to_bounce_buffer(struct scatterlist *orig_sgl,
703 					  struct scatterlist *bounce_sgl,
704 					  unsigned int orig_sgl_count)
705 {
706 	int i;
707 	int j = 0;
708 	unsigned long src, dest;
709 	unsigned int srclen, destlen, copylen;
710 	unsigned int total_copied = 0;
711 	unsigned long bounce_addr = 0;
712 	unsigned long src_addr = 0;
713 	unsigned long flags;
714 
715 	local_irq_save(flags);
716 
717 	for (i = 0; i < orig_sgl_count; i++) {
718 		src_addr = sg_kmap_atomic(orig_sgl,i) + orig_sgl[i].offset;
719 		src = src_addr;
720 		srclen = orig_sgl[i].length;
721 
722 		if (bounce_addr == 0)
723 			bounce_addr = sg_kmap_atomic(bounce_sgl,j);
724 
725 		while (srclen) {
726 			/* assume bounce offset always == 0 */
727 			dest = bounce_addr + bounce_sgl[j].length;
728 			destlen = PAGE_SIZE - bounce_sgl[j].length;
729 
730 			copylen = min(srclen, destlen);
731 			memcpy((void *)dest, (void *)src, copylen);
732 
733 			total_copied += copylen;
734 			bounce_sgl[j].length += copylen;
735 			srclen -= copylen;
736 			src += copylen;
737 
738 			if (bounce_sgl[j].length == PAGE_SIZE) {
739 				/* full..move to next entry */
740 				sg_kunmap_atomic(bounce_addr);
741 				j++;
742 
743 				/* if we need to use another bounce buffer */
744 				if (srclen || i != orig_sgl_count - 1)
745 					bounce_addr = sg_kmap_atomic(bounce_sgl,j);
746 
747 			} else if (srclen == 0 && i == orig_sgl_count - 1) {
748 				/* unmap the last bounce that is < PAGE_SIZE */
749 				sg_kunmap_atomic(bounce_addr);
750 			}
751 		}
752 
753 		sg_kunmap_atomic(src_addr - orig_sgl[i].offset);
754 	}
755 
756 	local_irq_restore(flags);
757 
758 	return total_copied;
759 }
760 
761 static void handle_sc_creation(struct vmbus_channel *new_sc)
762 {
763 	struct hv_device *device = new_sc->primary_channel->device_obj;
764 	struct storvsc_device *stor_device;
765 	struct vmstorage_channel_properties props;
766 
767 	stor_device = get_out_stor_device(device);
768 	if (!stor_device)
769 		return;
770 
771 	if (stor_device->open_sub_channel == false)
772 		return;
773 
774 	memset(&props, 0, sizeof(struct vmstorage_channel_properties));
775 
776 	vmbus_open(new_sc,
777 		   storvsc_ringbuffer_size,
778 		   storvsc_ringbuffer_size,
779 		   (void *)&props,
780 		   sizeof(struct vmstorage_channel_properties),
781 		   storvsc_on_channel_callback, new_sc);
782 }
783 
784 static void  handle_multichannel_storage(struct hv_device *device, int max_chns)
785 {
786 	struct storvsc_device *stor_device;
787 	int num_cpus = num_online_cpus();
788 	int num_sc;
789 	struct storvsc_cmd_request *request;
790 	struct vstor_packet *vstor_packet;
791 	int ret, t;
792 
793 	num_sc = ((max_chns > num_cpus) ? num_cpus : max_chns);
794 	stor_device = get_out_stor_device(device);
795 	if (!stor_device)
796 		return;
797 
798 	request = &stor_device->init_request;
799 	vstor_packet = &request->vstor_packet;
800 
801 	stor_device->open_sub_channel = true;
802 	/*
803 	 * Establish a handler for dealing with subchannels.
804 	 */
805 	vmbus_set_sc_create_callback(device->channel, handle_sc_creation);
806 
807 	/*
808 	 * Check to see if sub-channels have already been created. This
809 	 * can happen when this driver is re-loaded after unloading.
810 	 */
811 
812 	if (vmbus_are_subchannels_present(device->channel))
813 		return;
814 
815 	stor_device->open_sub_channel = false;
816 	/*
817 	 * Request the host to create sub-channels.
818 	 */
819 	memset(request, 0, sizeof(struct storvsc_cmd_request));
820 	init_completion(&request->wait_event);
821 	vstor_packet->operation = VSTOR_OPERATION_CREATE_SUB_CHANNELS;
822 	vstor_packet->flags = REQUEST_COMPLETION_FLAG;
823 	vstor_packet->sub_channel_count = num_sc;
824 
825 	ret = vmbus_sendpacket(device->channel, vstor_packet,
826 			       (sizeof(struct vstor_packet) -
827 			       vmscsi_size_delta),
828 			       (unsigned long)request,
829 			       VM_PKT_DATA_INBAND,
830 			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
831 
832 	if (ret != 0)
833 		return;
834 
835 	t = wait_for_completion_timeout(&request->wait_event, 10*HZ);
836 	if (t == 0)
837 		return;
838 
839 	if (vstor_packet->operation != VSTOR_OPERATION_COMPLETE_IO ||
840 	    vstor_packet->status != 0)
841 		return;
842 
843 	/*
844 	 * Now that we created the sub-channels, invoke the check; this
845 	 * may trigger the callback.
846 	 */
847 	stor_device->open_sub_channel = true;
848 	vmbus_are_subchannels_present(device->channel);
849 }
850 
851 static int storvsc_channel_init(struct hv_device *device)
852 {
853 	struct storvsc_device *stor_device;
854 	struct storvsc_cmd_request *request;
855 	struct vstor_packet *vstor_packet;
856 	int ret, t;
857 	int max_chns;
858 	bool process_sub_channels = false;
859 
860 	stor_device = get_out_stor_device(device);
861 	if (!stor_device)
862 		return -ENODEV;
863 
864 	request = &stor_device->init_request;
865 	vstor_packet = &request->vstor_packet;
866 
867 	/*
868 	 * Now, initiate the vsc/vsp initialization protocol on the open
869 	 * channel
870 	 */
871 	memset(request, 0, sizeof(struct storvsc_cmd_request));
872 	init_completion(&request->wait_event);
873 	vstor_packet->operation = VSTOR_OPERATION_BEGIN_INITIALIZATION;
874 	vstor_packet->flags = REQUEST_COMPLETION_FLAG;
875 
876 	ret = vmbus_sendpacket(device->channel, vstor_packet,
877 			       (sizeof(struct vstor_packet) -
878 			       vmscsi_size_delta),
879 			       (unsigned long)request,
880 			       VM_PKT_DATA_INBAND,
881 			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
882 	if (ret != 0)
883 		goto cleanup;
884 
885 	t = wait_for_completion_timeout(&request->wait_event, 5*HZ);
886 	if (t == 0) {
887 		ret = -ETIMEDOUT;
888 		goto cleanup;
889 	}
890 
891 	if (vstor_packet->operation != VSTOR_OPERATION_COMPLETE_IO ||
892 	    vstor_packet->status != 0)
893 		goto cleanup;
894 
895 
896 	/* reuse the packet for version range supported */
897 	memset(vstor_packet, 0, sizeof(struct vstor_packet));
898 	vstor_packet->operation = VSTOR_OPERATION_QUERY_PROTOCOL_VERSION;
899 	vstor_packet->flags = REQUEST_COMPLETION_FLAG;
900 
901 	vstor_packet->version.major_minor =
902 		storvsc_get_version(vmstor_current_major, vmstor_current_minor);
903 
904 	/*
905 	 * The revision number is only used in Windows; set it to 0.
906 	 */
907 	vstor_packet->version.revision = 0;
908 
909 	ret = vmbus_sendpacket(device->channel, vstor_packet,
910 			       (sizeof(struct vstor_packet) -
911 				vmscsi_size_delta),
912 			       (unsigned long)request,
913 			       VM_PKT_DATA_INBAND,
914 			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
915 	if (ret != 0)
916 		goto cleanup;
917 
918 	t = wait_for_completion_timeout(&request->wait_event, 5*HZ);
919 	if (t == 0) {
920 		ret = -ETIMEDOUT;
921 		goto cleanup;
922 	}
923 
924 	if (vstor_packet->operation != VSTOR_OPERATION_COMPLETE_IO ||
925 	    vstor_packet->status != 0)
926 		goto cleanup;
927 
928 
929 	memset(vstor_packet, 0, sizeof(struct vstor_packet));
930 	vstor_packet->operation = VSTOR_OPERATION_QUERY_PROPERTIES;
931 	vstor_packet->flags = REQUEST_COMPLETION_FLAG;
932 
933 	ret = vmbus_sendpacket(device->channel, vstor_packet,
934 			       (sizeof(struct vstor_packet) -
935 				vmscsi_size_delta),
936 			       (unsigned long)request,
937 			       VM_PKT_DATA_INBAND,
938 			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
939 
940 	if (ret != 0)
941 		goto cleanup;
942 
943 	t = wait_for_completion_timeout(&request->wait_event, 5*HZ);
944 	if (t == 0) {
945 		ret = -ETIMEDOUT;
946 		goto cleanup;
947 	}
948 
949 	if (vstor_packet->operation != VSTOR_OPERATION_COMPLETE_IO ||
950 	    vstor_packet->status != 0)
951 		goto cleanup;
952 
953 	/*
954 	 * Check to see if multi-channel support is there.
955 	 * Hosts that implement protocol version of 5.1 and above
956 	 * support multi-channel.
957 	 */
958 	max_chns = vstor_packet->storage_channel_properties.max_channel_cnt;
959 	if ((vmbus_proto_version != VERSION_WIN7) &&
960 	   (vmbus_proto_version != VERSION_WS2008))  {
961 		if (vstor_packet->storage_channel_properties.flags &
962 		    STORAGE_CHANNEL_SUPPORTS_MULTI_CHANNEL)
963 			process_sub_channels = true;
964 	}
965 
966 	memset(vstor_packet, 0, sizeof(struct vstor_packet));
967 	vstor_packet->operation = VSTOR_OPERATION_END_INITIALIZATION;
968 	vstor_packet->flags = REQUEST_COMPLETION_FLAG;
969 
970 	ret = vmbus_sendpacket(device->channel, vstor_packet,
971 			       (sizeof(struct vstor_packet) -
972 				vmscsi_size_delta),
973 			       (unsigned long)request,
974 			       VM_PKT_DATA_INBAND,
975 			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
976 
977 	if (ret != 0)
978 		goto cleanup;
979 
980 	t = wait_for_completion_timeout(&request->wait_event, 5*HZ);
981 	if (t == 0) {
982 		ret = -ETIMEDOUT;
983 		goto cleanup;
984 	}
985 
986 	if (vstor_packet->operation != VSTOR_OPERATION_COMPLETE_IO ||
987 	    vstor_packet->status != 0)
988 		goto cleanup;
989 
990 	if (process_sub_channels)
991 		handle_multichannel_storage(device, max_chns);
992 
993 
994 cleanup:
995 	return ret;
996 }
997 
998 static void storvsc_handle_error(struct vmscsi_request *vm_srb,
999 				struct scsi_cmnd *scmnd,
1000 				struct Scsi_Host *host,
1001 				u8 asc, u8 ascq)
1002 {
1003 	struct storvsc_scan_work *wrk;
1004 	void (*process_err_fn)(struct work_struct *work);
1005 	bool do_work = false;
1006 
1007 	switch (vm_srb->srb_status) {
1008 	case SRB_STATUS_ERROR:
1009 		/*
1010 		 * If there is an error; offline the device since all
1011 		 * error recovery strategies would have already been
1012 		 * deployed on the host side. However, if the command
1013 		 * were a pass-through command deal with it appropriately.
1014 		 */
1015 		switch (scmnd->cmnd[0]) {
1016 		case ATA_16:
1017 		case ATA_12:
1018 			set_host_byte(scmnd, DID_PASSTHROUGH);
1019 			break;
1020 		default:
1021 			set_host_byte(scmnd, DID_TARGET_FAILURE);
1022 		}
1023 		break;
1024 	case SRB_STATUS_INVALID_LUN:
1025 		do_work = true;
1026 		process_err_fn = storvsc_remove_lun;
1027 		break;
1028 	case (SRB_STATUS_ABORTED | SRB_STATUS_AUTOSENSE_VALID):
1029 		if ((asc == 0x2a) && (ascq == 0x9)) {
1030 			do_work = true;
1031 			process_err_fn = storvsc_device_scan;
1032 			/*
1033 			 * Retry the I/O that trigerred this.
1034 			 */
1035 			set_host_byte(scmnd, DID_REQUEUE);
1036 		}
1037 		break;
1038 	}
1039 
1040 	if (!do_work)
1041 		return;
1042 
1043 	/*
1044 	 * We need to schedule work to process this error; schedule it.
1045 	 */
1046 	wrk = kmalloc(sizeof(struct storvsc_scan_work), GFP_ATOMIC);
1047 	if (!wrk) {
1048 		set_host_byte(scmnd, DID_TARGET_FAILURE);
1049 		return;
1050 	}
1051 
1052 	wrk->host = host;
1053 	wrk->lun = vm_srb->lun;
1054 	INIT_WORK(&wrk->work, process_err_fn);
1055 	schedule_work(&wrk->work);
1056 }
1057 
1058 
1059 static void storvsc_command_completion(struct storvsc_cmd_request *cmd_request)
1060 {
1061 	struct scsi_cmnd *scmnd = cmd_request->cmd;
1062 	struct hv_host_device *host_dev = shost_priv(scmnd->device->host);
1063 	void (*scsi_done_fn)(struct scsi_cmnd *);
1064 	struct scsi_sense_hdr sense_hdr;
1065 	struct vmscsi_request *vm_srb;
1066 	struct stor_mem_pools *memp = scmnd->device->hostdata;
1067 	struct Scsi_Host *host;
1068 	struct storvsc_device *stor_dev;
1069 	struct hv_device *dev = host_dev->dev;
1070 
1071 	stor_dev = get_in_stor_device(dev);
1072 	host = stor_dev->host;
1073 
1074 	vm_srb = &cmd_request->vstor_packet.vm_srb;
1075 	if (cmd_request->bounce_sgl_count) {
1076 		if (vm_srb->data_in == READ_TYPE)
1077 			copy_from_bounce_buffer(scsi_sglist(scmnd),
1078 					cmd_request->bounce_sgl,
1079 					scsi_sg_count(scmnd),
1080 					cmd_request->bounce_sgl_count);
1081 		destroy_bounce_buffer(cmd_request->bounce_sgl,
1082 					cmd_request->bounce_sgl_count);
1083 	}
1084 
1085 	scmnd->result = vm_srb->scsi_status;
1086 
1087 	if (scmnd->result) {
1088 		if (scsi_normalize_sense(scmnd->sense_buffer,
1089 				SCSI_SENSE_BUFFERSIZE, &sense_hdr))
1090 			scsi_print_sense_hdr("storvsc", &sense_hdr);
1091 	}
1092 
1093 	if (vm_srb->srb_status != SRB_STATUS_SUCCESS)
1094 		storvsc_handle_error(vm_srb, scmnd, host, sense_hdr.asc,
1095 					 sense_hdr.ascq);
1096 
1097 	scsi_set_resid(scmnd,
1098 		cmd_request->data_buffer.len -
1099 		vm_srb->data_transfer_length);
1100 
1101 	scsi_done_fn = scmnd->scsi_done;
1102 
1103 	scmnd->host_scribble = NULL;
1104 	scmnd->scsi_done = NULL;
1105 
1106 	scsi_done_fn(scmnd);
1107 
1108 	mempool_free(cmd_request, memp->request_mempool);
1109 }
1110 
1111 static void storvsc_on_io_completion(struct hv_device *device,
1112 				  struct vstor_packet *vstor_packet,
1113 				  struct storvsc_cmd_request *request)
1114 {
1115 	struct storvsc_device *stor_device;
1116 	struct vstor_packet *stor_pkt;
1117 
1118 	stor_device = hv_get_drvdata(device);
1119 	stor_pkt = &request->vstor_packet;
1120 
1121 	/*
1122 	 * The current SCSI handling on the host side does
1123 	 * not correctly handle:
1124 	 * INQUIRY command with page code parameter set to 0x80
1125 	 * MODE_SENSE command with cmd[2] == 0x1c
1126 	 *
1127 	 * Setup srb and scsi status so this won't be fatal.
1128 	 * We do this so we can distinguish truly fatal failues
1129 	 * (srb status == 0x4) and off-line the device in that case.
1130 	 */
1131 
1132 	if ((stor_pkt->vm_srb.cdb[0] == INQUIRY) ||
1133 	   (stor_pkt->vm_srb.cdb[0] == MODE_SENSE)) {
1134 		vstor_packet->vm_srb.scsi_status = 0;
1135 		vstor_packet->vm_srb.srb_status = SRB_STATUS_SUCCESS;
1136 	}
1137 
1138 
1139 	/* Copy over the status...etc */
1140 	stor_pkt->vm_srb.scsi_status = vstor_packet->vm_srb.scsi_status;
1141 	stor_pkt->vm_srb.srb_status = vstor_packet->vm_srb.srb_status;
1142 	stor_pkt->vm_srb.sense_info_length =
1143 	vstor_packet->vm_srb.sense_info_length;
1144 
1145 	if (vstor_packet->vm_srb.scsi_status != 0 ||
1146 		vstor_packet->vm_srb.srb_status != SRB_STATUS_SUCCESS){
1147 		dev_warn(&device->device,
1148 			 "cmd 0x%x scsi status 0x%x srb status 0x%x\n",
1149 			 stor_pkt->vm_srb.cdb[0],
1150 			 vstor_packet->vm_srb.scsi_status,
1151 			 vstor_packet->vm_srb.srb_status);
1152 	}
1153 
1154 	if ((vstor_packet->vm_srb.scsi_status & 0xFF) == 0x02) {
1155 		/* CHECK_CONDITION */
1156 		if (vstor_packet->vm_srb.srb_status &
1157 			SRB_STATUS_AUTOSENSE_VALID) {
1158 			/* autosense data available */
1159 			dev_warn(&device->device,
1160 				 "stor pkt %p autosense data valid - len %d\n",
1161 				 request,
1162 				 vstor_packet->vm_srb.sense_info_length);
1163 
1164 			memcpy(request->sense_buffer,
1165 			       vstor_packet->vm_srb.sense_data,
1166 			       vstor_packet->vm_srb.sense_info_length);
1167 
1168 		}
1169 	}
1170 
1171 	stor_pkt->vm_srb.data_transfer_length =
1172 	vstor_packet->vm_srb.data_transfer_length;
1173 
1174 	storvsc_command_completion(request);
1175 
1176 	if (atomic_dec_and_test(&stor_device->num_outstanding_req) &&
1177 		stor_device->drain_notify)
1178 		wake_up(&stor_device->waiting_to_drain);
1179 
1180 
1181 }
1182 
1183 static void storvsc_on_receive(struct hv_device *device,
1184 			     struct vstor_packet *vstor_packet,
1185 			     struct storvsc_cmd_request *request)
1186 {
1187 	struct storvsc_scan_work *work;
1188 	struct storvsc_device *stor_device;
1189 
1190 	switch (vstor_packet->operation) {
1191 	case VSTOR_OPERATION_COMPLETE_IO:
1192 		storvsc_on_io_completion(device, vstor_packet, request);
1193 		break;
1194 
1195 	case VSTOR_OPERATION_REMOVE_DEVICE:
1196 	case VSTOR_OPERATION_ENUMERATE_BUS:
1197 		stor_device = get_in_stor_device(device);
1198 		work = kmalloc(sizeof(struct storvsc_scan_work), GFP_ATOMIC);
1199 		if (!work)
1200 			return;
1201 
1202 		INIT_WORK(&work->work, storvsc_bus_scan);
1203 		work->host = stor_device->host;
1204 		schedule_work(&work->work);
1205 		break;
1206 
1207 	default:
1208 		break;
1209 	}
1210 }
1211 
1212 static void storvsc_on_channel_callback(void *context)
1213 {
1214 	struct vmbus_channel *channel = (struct vmbus_channel *)context;
1215 	struct hv_device *device;
1216 	struct storvsc_device *stor_device;
1217 	u32 bytes_recvd;
1218 	u64 request_id;
1219 	unsigned char packet[ALIGN(sizeof(struct vstor_packet), 8)];
1220 	struct storvsc_cmd_request *request;
1221 	int ret;
1222 
1223 	if (channel->primary_channel != NULL)
1224 		device = channel->primary_channel->device_obj;
1225 	else
1226 		device = channel->device_obj;
1227 
1228 	stor_device = get_in_stor_device(device);
1229 	if (!stor_device)
1230 		return;
1231 
1232 	do {
1233 		ret = vmbus_recvpacket(channel, packet,
1234 				       ALIGN((sizeof(struct vstor_packet) -
1235 					     vmscsi_size_delta), 8),
1236 				       &bytes_recvd, &request_id);
1237 		if (ret == 0 && bytes_recvd > 0) {
1238 
1239 			request = (struct storvsc_cmd_request *)
1240 					(unsigned long)request_id;
1241 
1242 			if ((request == &stor_device->init_request) ||
1243 			    (request == &stor_device->reset_request)) {
1244 
1245 				memcpy(&request->vstor_packet, packet,
1246 				       (sizeof(struct vstor_packet) -
1247 					vmscsi_size_delta));
1248 				complete(&request->wait_event);
1249 			} else {
1250 				storvsc_on_receive(device,
1251 						(struct vstor_packet *)packet,
1252 						request);
1253 			}
1254 		} else {
1255 			break;
1256 		}
1257 	} while (1);
1258 
1259 	return;
1260 }
1261 
1262 static int storvsc_connect_to_vsp(struct hv_device *device, u32 ring_size)
1263 {
1264 	struct vmstorage_channel_properties props;
1265 	int ret;
1266 
1267 	memset(&props, 0, sizeof(struct vmstorage_channel_properties));
1268 
1269 	ret = vmbus_open(device->channel,
1270 			 ring_size,
1271 			 ring_size,
1272 			 (void *)&props,
1273 			 sizeof(struct vmstorage_channel_properties),
1274 			 storvsc_on_channel_callback, device->channel);
1275 
1276 	if (ret != 0)
1277 		return ret;
1278 
1279 	ret = storvsc_channel_init(device);
1280 
1281 	return ret;
1282 }
1283 
1284 static int storvsc_dev_remove(struct hv_device *device)
1285 {
1286 	struct storvsc_device *stor_device;
1287 	unsigned long flags;
1288 
1289 	stor_device = hv_get_drvdata(device);
1290 
1291 	spin_lock_irqsave(&device->channel->inbound_lock, flags);
1292 	stor_device->destroy = true;
1293 	spin_unlock_irqrestore(&device->channel->inbound_lock, flags);
1294 
1295 	/*
1296 	 * At this point, all outbound traffic should be disable. We
1297 	 * only allow inbound traffic (responses) to proceed so that
1298 	 * outstanding requests can be completed.
1299 	 */
1300 
1301 	storvsc_wait_to_drain(stor_device);
1302 
1303 	/*
1304 	 * Since we have already drained, we don't need to busy wait
1305 	 * as was done in final_release_stor_device()
1306 	 * Note that we cannot set the ext pointer to NULL until
1307 	 * we have drained - to drain the outgoing packets, we need to
1308 	 * allow incoming packets.
1309 	 */
1310 	spin_lock_irqsave(&device->channel->inbound_lock, flags);
1311 	hv_set_drvdata(device, NULL);
1312 	spin_unlock_irqrestore(&device->channel->inbound_lock, flags);
1313 
1314 	/* Close the channel */
1315 	vmbus_close(device->channel);
1316 
1317 	kfree(stor_device);
1318 	return 0;
1319 }
1320 
1321 static int storvsc_do_io(struct hv_device *device,
1322 			      struct storvsc_cmd_request *request)
1323 {
1324 	struct storvsc_device *stor_device;
1325 	struct vstor_packet *vstor_packet;
1326 	struct vmbus_channel *outgoing_channel;
1327 	int ret = 0;
1328 
1329 	vstor_packet = &request->vstor_packet;
1330 	stor_device = get_out_stor_device(device);
1331 
1332 	if (!stor_device)
1333 		return -ENODEV;
1334 
1335 
1336 	request->device  = device;
1337 	/*
1338 	 * Select an an appropriate channel to send the request out.
1339 	 */
1340 
1341 	outgoing_channel = vmbus_get_outgoing_channel(device->channel);
1342 
1343 
1344 	vstor_packet->flags |= REQUEST_COMPLETION_FLAG;
1345 
1346 	vstor_packet->vm_srb.length = (sizeof(struct vmscsi_request) -
1347 					vmscsi_size_delta);
1348 
1349 
1350 	vstor_packet->vm_srb.sense_info_length = sense_buffer_size;
1351 
1352 
1353 	vstor_packet->vm_srb.data_transfer_length =
1354 	request->data_buffer.len;
1355 
1356 	vstor_packet->operation = VSTOR_OPERATION_EXECUTE_SRB;
1357 
1358 	if (request->data_buffer.len) {
1359 		ret = vmbus_sendpacket_multipagebuffer(outgoing_channel,
1360 				&request->data_buffer,
1361 				vstor_packet,
1362 				(sizeof(struct vstor_packet) -
1363 				vmscsi_size_delta),
1364 				(unsigned long)request);
1365 	} else {
1366 		ret = vmbus_sendpacket(device->channel, vstor_packet,
1367 			       (sizeof(struct vstor_packet) -
1368 				vmscsi_size_delta),
1369 			       (unsigned long)request,
1370 			       VM_PKT_DATA_INBAND,
1371 			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
1372 	}
1373 
1374 	if (ret != 0)
1375 		return ret;
1376 
1377 	atomic_inc(&stor_device->num_outstanding_req);
1378 
1379 	return ret;
1380 }
1381 
1382 static int storvsc_device_alloc(struct scsi_device *sdevice)
1383 {
1384 	struct stor_mem_pools *memp;
1385 	int number = STORVSC_MIN_BUF_NR;
1386 
1387 	memp = kzalloc(sizeof(struct stor_mem_pools), GFP_KERNEL);
1388 	if (!memp)
1389 		return -ENOMEM;
1390 
1391 	memp->request_pool =
1392 		kmem_cache_create(dev_name(&sdevice->sdev_dev),
1393 				sizeof(struct storvsc_cmd_request), 0,
1394 				SLAB_HWCACHE_ALIGN, NULL);
1395 
1396 	if (!memp->request_pool)
1397 		goto err0;
1398 
1399 	memp->request_mempool = mempool_create(number, mempool_alloc_slab,
1400 						mempool_free_slab,
1401 						memp->request_pool);
1402 
1403 	if (!memp->request_mempool)
1404 		goto err1;
1405 
1406 	sdevice->hostdata = memp;
1407 
1408 	return 0;
1409 
1410 err1:
1411 	kmem_cache_destroy(memp->request_pool);
1412 
1413 err0:
1414 	kfree(memp);
1415 	return -ENOMEM;
1416 }
1417 
1418 static void storvsc_device_destroy(struct scsi_device *sdevice)
1419 {
1420 	struct stor_mem_pools *memp = sdevice->hostdata;
1421 
1422 	mempool_destroy(memp->request_mempool);
1423 	kmem_cache_destroy(memp->request_pool);
1424 	kfree(memp);
1425 	sdevice->hostdata = NULL;
1426 }
1427 
1428 static int storvsc_device_configure(struct scsi_device *sdevice)
1429 {
1430 	scsi_adjust_queue_depth(sdevice, MSG_SIMPLE_TAG,
1431 				STORVSC_MAX_IO_REQUESTS);
1432 
1433 	blk_queue_max_segment_size(sdevice->request_queue, PAGE_SIZE);
1434 
1435 	blk_queue_bounce_limit(sdevice->request_queue, BLK_BOUNCE_ANY);
1436 
1437 	blk_queue_rq_timeout(sdevice->request_queue, (storvsc_timeout * HZ));
1438 
1439 	sdevice->no_write_same = 1;
1440 
1441 	return 0;
1442 }
1443 
1444 static int storvsc_get_chs(struct scsi_device *sdev, struct block_device * bdev,
1445 			   sector_t capacity, int *info)
1446 {
1447 	sector_t nsect = capacity;
1448 	sector_t cylinders = nsect;
1449 	int heads, sectors_pt;
1450 
1451 	/*
1452 	 * We are making up these values; let us keep it simple.
1453 	 */
1454 	heads = 0xff;
1455 	sectors_pt = 0x3f;      /* Sectors per track */
1456 	sector_div(cylinders, heads * sectors_pt);
1457 	if ((sector_t)(cylinders + 1) * heads * sectors_pt < nsect)
1458 		cylinders = 0xffff;
1459 
1460 	info[0] = heads;
1461 	info[1] = sectors_pt;
1462 	info[2] = (int)cylinders;
1463 
1464 	return 0;
1465 }
1466 
1467 static int storvsc_host_reset_handler(struct scsi_cmnd *scmnd)
1468 {
1469 	struct hv_host_device *host_dev = shost_priv(scmnd->device->host);
1470 	struct hv_device *device = host_dev->dev;
1471 
1472 	struct storvsc_device *stor_device;
1473 	struct storvsc_cmd_request *request;
1474 	struct vstor_packet *vstor_packet;
1475 	int ret, t;
1476 
1477 
1478 	stor_device = get_out_stor_device(device);
1479 	if (!stor_device)
1480 		return FAILED;
1481 
1482 	request = &stor_device->reset_request;
1483 	vstor_packet = &request->vstor_packet;
1484 
1485 	init_completion(&request->wait_event);
1486 
1487 	vstor_packet->operation = VSTOR_OPERATION_RESET_BUS;
1488 	vstor_packet->flags = REQUEST_COMPLETION_FLAG;
1489 	vstor_packet->vm_srb.path_id = stor_device->path_id;
1490 
1491 	ret = vmbus_sendpacket(device->channel, vstor_packet,
1492 			       (sizeof(struct vstor_packet) -
1493 				vmscsi_size_delta),
1494 			       (unsigned long)&stor_device->reset_request,
1495 			       VM_PKT_DATA_INBAND,
1496 			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
1497 	if (ret != 0)
1498 		return FAILED;
1499 
1500 	t = wait_for_completion_timeout(&request->wait_event, 5*HZ);
1501 	if (t == 0)
1502 		return TIMEOUT_ERROR;
1503 
1504 
1505 	/*
1506 	 * At this point, all outstanding requests in the adapter
1507 	 * should have been flushed out and return to us
1508 	 * There is a potential race here where the host may be in
1509 	 * the process of responding when we return from here.
1510 	 * Just wait for all in-transit packets to be accounted for
1511 	 * before we return from here.
1512 	 */
1513 	storvsc_wait_to_drain(stor_device);
1514 
1515 	return SUCCESS;
1516 }
1517 
1518 static bool storvsc_scsi_cmd_ok(struct scsi_cmnd *scmnd)
1519 {
1520 	bool allowed = true;
1521 	u8 scsi_op = scmnd->cmnd[0];
1522 
1523 	switch (scsi_op) {
1524 	/* the host does not handle WRITE_SAME, log accident usage */
1525 	case WRITE_SAME:
1526 	/*
1527 	 * smartd sends this command and the host does not handle
1528 	 * this. So, don't send it.
1529 	 */
1530 	case SET_WINDOW:
1531 		scmnd->result = ILLEGAL_REQUEST << 16;
1532 		allowed = false;
1533 		break;
1534 	default:
1535 		break;
1536 	}
1537 	return allowed;
1538 }
1539 
1540 static int storvsc_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *scmnd)
1541 {
1542 	int ret;
1543 	struct hv_host_device *host_dev = shost_priv(host);
1544 	struct hv_device *dev = host_dev->dev;
1545 	struct storvsc_cmd_request *cmd_request;
1546 	unsigned int request_size = 0;
1547 	int i;
1548 	struct scatterlist *sgl;
1549 	unsigned int sg_count = 0;
1550 	struct vmscsi_request *vm_srb;
1551 	struct stor_mem_pools *memp = scmnd->device->hostdata;
1552 
1553 	if (!storvsc_scsi_cmd_ok(scmnd)) {
1554 		scmnd->scsi_done(scmnd);
1555 		return 0;
1556 	}
1557 
1558 	request_size = sizeof(struct storvsc_cmd_request);
1559 
1560 	cmd_request = mempool_alloc(memp->request_mempool,
1561 				       GFP_ATOMIC);
1562 
1563 	/*
1564 	 * We might be invoked in an interrupt context; hence
1565 	 * mempool_alloc() can fail.
1566 	 */
1567 	if (!cmd_request)
1568 		return SCSI_MLQUEUE_DEVICE_BUSY;
1569 
1570 	memset(cmd_request, 0, sizeof(struct storvsc_cmd_request));
1571 
1572 	/* Setup the cmd request */
1573 	cmd_request->cmd = scmnd;
1574 
1575 	scmnd->host_scribble = (unsigned char *)cmd_request;
1576 
1577 	vm_srb = &cmd_request->vstor_packet.vm_srb;
1578 	vm_srb->win8_extension.time_out_value = 60;
1579 
1580 
1581 	/* Build the SRB */
1582 	switch (scmnd->sc_data_direction) {
1583 	case DMA_TO_DEVICE:
1584 		vm_srb->data_in = WRITE_TYPE;
1585 		vm_srb->win8_extension.srb_flags |= SRB_FLAGS_DATA_OUT;
1586 		vm_srb->win8_extension.srb_flags |=
1587 			(SRB_FLAGS_QUEUE_ACTION_ENABLE |
1588 			SRB_FLAGS_DISABLE_SYNCH_TRANSFER);
1589 		break;
1590 	case DMA_FROM_DEVICE:
1591 		vm_srb->data_in = READ_TYPE;
1592 		vm_srb->win8_extension.srb_flags |= SRB_FLAGS_DATA_IN;
1593 		vm_srb->win8_extension.srb_flags |=
1594 			(SRB_FLAGS_QUEUE_ACTION_ENABLE |
1595 			SRB_FLAGS_DISABLE_SYNCH_TRANSFER);
1596 		break;
1597 	default:
1598 		vm_srb->data_in = UNKNOWN_TYPE;
1599 		vm_srb->win8_extension.srb_flags = 0;
1600 		break;
1601 	}
1602 
1603 
1604 	vm_srb->port_number = host_dev->port;
1605 	vm_srb->path_id = scmnd->device->channel;
1606 	vm_srb->target_id = scmnd->device->id;
1607 	vm_srb->lun = scmnd->device->lun;
1608 
1609 	vm_srb->cdb_length = scmnd->cmd_len;
1610 
1611 	memcpy(vm_srb->cdb, scmnd->cmnd, vm_srb->cdb_length);
1612 
1613 	cmd_request->sense_buffer = scmnd->sense_buffer;
1614 
1615 
1616 	cmd_request->data_buffer.len = scsi_bufflen(scmnd);
1617 	if (scsi_sg_count(scmnd)) {
1618 		sgl = (struct scatterlist *)scsi_sglist(scmnd);
1619 		sg_count = scsi_sg_count(scmnd);
1620 
1621 		/* check if we need to bounce the sgl */
1622 		if (do_bounce_buffer(sgl, scsi_sg_count(scmnd)) != -1) {
1623 			cmd_request->bounce_sgl =
1624 				create_bounce_buffer(sgl, scsi_sg_count(scmnd),
1625 						     scsi_bufflen(scmnd),
1626 						     vm_srb->data_in);
1627 			if (!cmd_request->bounce_sgl) {
1628 				ret = SCSI_MLQUEUE_HOST_BUSY;
1629 				goto queue_error;
1630 			}
1631 
1632 			cmd_request->bounce_sgl_count =
1633 				ALIGN(scsi_bufflen(scmnd), PAGE_SIZE) >>
1634 					PAGE_SHIFT;
1635 
1636 			if (vm_srb->data_in == WRITE_TYPE)
1637 				copy_to_bounce_buffer(sgl,
1638 					cmd_request->bounce_sgl,
1639 					scsi_sg_count(scmnd));
1640 
1641 			sgl = cmd_request->bounce_sgl;
1642 			sg_count = cmd_request->bounce_sgl_count;
1643 		}
1644 
1645 		cmd_request->data_buffer.offset = sgl[0].offset;
1646 
1647 		for (i = 0; i < sg_count; i++)
1648 			cmd_request->data_buffer.pfn_array[i] =
1649 				page_to_pfn(sg_page((&sgl[i])));
1650 
1651 	} else if (scsi_sglist(scmnd)) {
1652 		cmd_request->data_buffer.offset =
1653 			virt_to_phys(scsi_sglist(scmnd)) & (PAGE_SIZE-1);
1654 		cmd_request->data_buffer.pfn_array[0] =
1655 			virt_to_phys(scsi_sglist(scmnd)) >> PAGE_SHIFT;
1656 	}
1657 
1658 	/* Invokes the vsc to start an IO */
1659 	ret = storvsc_do_io(dev, cmd_request);
1660 
1661 	if (ret == -EAGAIN) {
1662 		/* no more space */
1663 
1664 		if (cmd_request->bounce_sgl_count) {
1665 			destroy_bounce_buffer(cmd_request->bounce_sgl,
1666 					cmd_request->bounce_sgl_count);
1667 
1668 			ret = SCSI_MLQUEUE_DEVICE_BUSY;
1669 			goto queue_error;
1670 		}
1671 	}
1672 
1673 	return 0;
1674 
1675 queue_error:
1676 	mempool_free(cmd_request, memp->request_mempool);
1677 	scmnd->host_scribble = NULL;
1678 	return ret;
1679 }
1680 
1681 static struct scsi_host_template scsi_driver = {
1682 	.module	=		THIS_MODULE,
1683 	.name =			"storvsc_host_t",
1684 	.bios_param =		storvsc_get_chs,
1685 	.queuecommand =		storvsc_queuecommand,
1686 	.eh_host_reset_handler =	storvsc_host_reset_handler,
1687 	.slave_alloc =		storvsc_device_alloc,
1688 	.slave_destroy =	storvsc_device_destroy,
1689 	.slave_configure =	storvsc_device_configure,
1690 	.cmd_per_lun =		1,
1691 	/* 64 max_queue * 1 target */
1692 	.can_queue =		STORVSC_MAX_IO_REQUESTS*STORVSC_MAX_TARGETS,
1693 	.this_id =		-1,
1694 	/* no use setting to 0 since ll_blk_rw reset it to 1 */
1695 	/* currently 32 */
1696 	.sg_tablesize =		MAX_MULTIPAGE_BUFFER_COUNT,
1697 	.use_clustering =	DISABLE_CLUSTERING,
1698 	/* Make sure we dont get a sg segment crosses a page boundary */
1699 	.dma_boundary =		PAGE_SIZE-1,
1700 	.no_write_same =	1,
1701 };
1702 
1703 enum {
1704 	SCSI_GUID,
1705 	IDE_GUID,
1706 	SFC_GUID,
1707 };
1708 
1709 static const struct hv_vmbus_device_id id_table[] = {
1710 	/* SCSI guid */
1711 	{ HV_SCSI_GUID,
1712 	  .driver_data = SCSI_GUID
1713 	},
1714 	/* IDE guid */
1715 	{ HV_IDE_GUID,
1716 	  .driver_data = IDE_GUID
1717 	},
1718 	/* Fibre Channel GUID */
1719 	{
1720 	  HV_SYNTHFC_GUID,
1721 	  .driver_data = SFC_GUID
1722 	},
1723 	{ },
1724 };
1725 
1726 MODULE_DEVICE_TABLE(vmbus, id_table);
1727 
1728 static int storvsc_probe(struct hv_device *device,
1729 			const struct hv_vmbus_device_id *dev_id)
1730 {
1731 	int ret;
1732 	struct Scsi_Host *host;
1733 	struct hv_host_device *host_dev;
1734 	bool dev_is_ide = ((dev_id->driver_data == IDE_GUID) ? true : false);
1735 	int target = 0;
1736 	struct storvsc_device *stor_device;
1737 
1738 	/*
1739 	 * Based on the windows host we are running on,
1740 	 * set state to properly communicate with the host.
1741 	 */
1742 
1743 	if (vmbus_proto_version == VERSION_WIN8) {
1744 		sense_buffer_size = POST_WIN7_STORVSC_SENSE_BUFFER_SIZE;
1745 		vmscsi_size_delta = 0;
1746 		vmstor_current_major = VMSTOR_WIN8_MAJOR;
1747 		vmstor_current_minor = VMSTOR_WIN8_MINOR;
1748 	} else {
1749 		sense_buffer_size = PRE_WIN8_STORVSC_SENSE_BUFFER_SIZE;
1750 		vmscsi_size_delta = sizeof(struct vmscsi_win8_extension);
1751 		vmstor_current_major = VMSTOR_WIN7_MAJOR;
1752 		vmstor_current_minor = VMSTOR_WIN7_MINOR;
1753 	}
1754 
1755 
1756 	host = scsi_host_alloc(&scsi_driver,
1757 			       sizeof(struct hv_host_device));
1758 	if (!host)
1759 		return -ENOMEM;
1760 
1761 	host_dev = shost_priv(host);
1762 	memset(host_dev, 0, sizeof(struct hv_host_device));
1763 
1764 	host_dev->port = host->host_no;
1765 	host_dev->dev = device;
1766 
1767 
1768 	stor_device = kzalloc(sizeof(struct storvsc_device), GFP_KERNEL);
1769 	if (!stor_device) {
1770 		ret = -ENOMEM;
1771 		goto err_out0;
1772 	}
1773 
1774 	stor_device->destroy = false;
1775 	stor_device->open_sub_channel = false;
1776 	init_waitqueue_head(&stor_device->waiting_to_drain);
1777 	stor_device->device = device;
1778 	stor_device->host = host;
1779 	hv_set_drvdata(device, stor_device);
1780 
1781 	stor_device->port_number = host->host_no;
1782 	ret = storvsc_connect_to_vsp(device, storvsc_ringbuffer_size);
1783 	if (ret)
1784 		goto err_out1;
1785 
1786 	host_dev->path = stor_device->path_id;
1787 	host_dev->target = stor_device->target_id;
1788 
1789 	/* max # of devices per target */
1790 	host->max_lun = STORVSC_MAX_LUNS_PER_TARGET;
1791 	/* max # of targets per channel */
1792 	host->max_id = STORVSC_MAX_TARGETS;
1793 	/* max # of channels */
1794 	host->max_channel = STORVSC_MAX_CHANNELS - 1;
1795 	/* max cmd length */
1796 	host->max_cmd_len = STORVSC_MAX_CMD_LEN;
1797 
1798 	/* Register the HBA and start the scsi bus scan */
1799 	ret = scsi_add_host(host, &device->device);
1800 	if (ret != 0)
1801 		goto err_out2;
1802 
1803 	if (!dev_is_ide) {
1804 		scsi_scan_host(host);
1805 	} else {
1806 		target = (device->dev_instance.b[5] << 8 |
1807 			 device->dev_instance.b[4]);
1808 		ret = scsi_add_device(host, 0, target, 0);
1809 		if (ret) {
1810 			scsi_remove_host(host);
1811 			goto err_out2;
1812 		}
1813 	}
1814 	return 0;
1815 
1816 err_out2:
1817 	/*
1818 	 * Once we have connected with the host, we would need to
1819 	 * to invoke storvsc_dev_remove() to rollback this state and
1820 	 * this call also frees up the stor_device; hence the jump around
1821 	 * err_out1 label.
1822 	 */
1823 	storvsc_dev_remove(device);
1824 	goto err_out0;
1825 
1826 err_out1:
1827 	kfree(stor_device);
1828 
1829 err_out0:
1830 	scsi_host_put(host);
1831 	return ret;
1832 }
1833 
1834 static int storvsc_remove(struct hv_device *dev)
1835 {
1836 	struct storvsc_device *stor_device = hv_get_drvdata(dev);
1837 	struct Scsi_Host *host = stor_device->host;
1838 
1839 	scsi_remove_host(host);
1840 	storvsc_dev_remove(dev);
1841 	scsi_host_put(host);
1842 
1843 	return 0;
1844 }
1845 
1846 static struct hv_driver storvsc_drv = {
1847 	.name = KBUILD_MODNAME,
1848 	.id_table = id_table,
1849 	.probe = storvsc_probe,
1850 	.remove = storvsc_remove,
1851 };
1852 
1853 static int __init storvsc_drv_init(void)
1854 {
1855 	u32 max_outstanding_req_per_channel;
1856 
1857 	/*
1858 	 * Divide the ring buffer data size (which is 1 page less
1859 	 * than the ring buffer size since that page is reserved for
1860 	 * the ring buffer indices) by the max request size (which is
1861 	 * vmbus_channel_packet_multipage_buffer + struct vstor_packet + u64)
1862 	 */
1863 	max_outstanding_req_per_channel =
1864 		((storvsc_ringbuffer_size - PAGE_SIZE) /
1865 		ALIGN(MAX_MULTIPAGE_BUFFER_PACKET +
1866 		sizeof(struct vstor_packet) + sizeof(u64) -
1867 		vmscsi_size_delta,
1868 		sizeof(u64)));
1869 
1870 	if (max_outstanding_req_per_channel <
1871 	    STORVSC_MAX_IO_REQUESTS)
1872 		return -EINVAL;
1873 
1874 	return vmbus_driver_register(&storvsc_drv);
1875 }
1876 
1877 static void __exit storvsc_drv_exit(void)
1878 {
1879 	vmbus_driver_unregister(&storvsc_drv);
1880 }
1881 
1882 MODULE_LICENSE("GPL");
1883 MODULE_DESCRIPTION("Microsoft Hyper-V virtual storage driver");
1884 module_init(storvsc_drv_init);
1885 module_exit(storvsc_drv_exit);
1886