Staging: hv: move hyperv code out of staging directory
[linux-2.6.git] / drivers / staging / hv / storvsc_drv.c
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 <scsi/scsi.h>
36 #include <scsi/scsi_cmnd.h>
37 #include <scsi/scsi_host.h>
38 #include <scsi/scsi_device.h>
39 #include <scsi/scsi_tcq.h>
40 #include <scsi/scsi_eh.h>
41 #include <scsi/scsi_devinfo.h>
42 #include <scsi/scsi_dbg.h>
43
44
45 #define STORVSC_RING_BUFFER_SIZE                        (20*PAGE_SIZE)
46 static int storvsc_ringbuffer_size = STORVSC_RING_BUFFER_SIZE;
47
48 module_param(storvsc_ringbuffer_size, int, S_IRUGO);
49 MODULE_PARM_DESC(storvsc_ringbuffer_size, "Ring buffer size (bytes)");
50
51 /* to alert the user that structure sizes may be mismatched even though the */
52 /* protocol versions match. */
53
54
55 #define REVISION_STRING(REVISION_) #REVISION_
56 #define FILL_VMSTOR_REVISION(RESULT_LVALUE_)                            \
57         do {                                                            \
58                 char *revision_string                                   \
59                         = REVISION_STRING($Rev : 6 $) + 6;              \
60                 RESULT_LVALUE_ = 0;                                     \
61                 while (*revision_string >= '0'                          \
62                         && *revision_string <= '9') {                   \
63                         RESULT_LVALUE_ *= 10;                           \
64                         RESULT_LVALUE_ += *revision_string - '0';       \
65                         revision_string++;                              \
66                 }                                                       \
67         } while (0)
68
69 /* Major/minor macros.  Minor version is in LSB, meaning that earlier flat */
70 /* version numbers will be interpreted as "0.x" (i.e., 1 becomes 0.1). */
71 #define VMSTOR_PROTOCOL_MAJOR(VERSION_)         (((VERSION_) >> 8) & 0xff)
72 #define VMSTOR_PROTOCOL_MINOR(VERSION_)         (((VERSION_))      & 0xff)
73 #define VMSTOR_PROTOCOL_VERSION(MAJOR_, MINOR_) ((((MAJOR_) & 0xff) << 8) | \
74                                                  (((MINOR_) & 0xff)))
75 #define VMSTOR_INVALID_PROTOCOL_VERSION         (-1)
76
77 /* Version history: */
78 /* V1 Beta                    0.1 */
79 /* V1 RC < 2008/1/31          1.0 */
80 /* V1 RC > 2008/1/31          2.0 */
81 #define VMSTOR_PROTOCOL_VERSION_CURRENT VMSTOR_PROTOCOL_VERSION(2, 0)
82
83
84
85
86 /*  This will get replaced with the max transfer length that is possible on */
87 /*  the host adapter. */
88 /*  The max transfer length will be published when we offer a vmbus channel. */
89 #define MAX_TRANSFER_LENGTH     0x40000
90 #define DEFAULT_PACKET_SIZE (sizeof(struct vmdata_gpa_direct) + \
91                         sizeof(struct vstor_packet) +           \
92                         sizesizeof(u64) * (MAX_TRANSFER_LENGTH / PAGE_SIZE)))
93
94
95 /*  Packet structure describing virtual storage requests. */
96 enum vstor_packet_operation {
97         VSTOR_OPERATION_COMPLETE_IO             = 1,
98         VSTOR_OPERATION_REMOVE_DEVICE           = 2,
99         VSTOR_OPERATION_EXECUTE_SRB             = 3,
100         VSTOR_OPERATION_RESET_LUN               = 4,
101         VSTOR_OPERATION_RESET_ADAPTER           = 5,
102         VSTOR_OPERATION_RESET_BUS               = 6,
103         VSTOR_OPERATION_BEGIN_INITIALIZATION    = 7,
104         VSTOR_OPERATION_END_INITIALIZATION      = 8,
105         VSTOR_OPERATION_QUERY_PROTOCOL_VERSION  = 9,
106         VSTOR_OPERATION_QUERY_PROPERTIES        = 10,
107         VSTOR_OPERATION_MAXIMUM                 = 10
108 };
109
110 /*
111  * Platform neutral description of a scsi request -
112  * this remains the same across the write regardless of 32/64 bit
113  * note: it's patterned off the SCSI_PASS_THROUGH structure
114  */
115 #define CDB16GENERIC_LENGTH                     0x10
116
117 #ifndef SENSE_BUFFER_SIZE
118 #define SENSE_BUFFER_SIZE                       0x12
119 #endif
120
121 #define MAX_DATA_BUF_LEN_WITH_PADDING           0x14
122
123 struct vmscsi_request {
124         unsigned short length;
125         unsigned char srb_status;
126         unsigned char scsi_status;
127
128         unsigned char port_number;
129         unsigned char path_id;
130         unsigned char target_id;
131         unsigned char lun;
132
133         unsigned char cdb_length;
134         unsigned char sense_info_length;
135         unsigned char data_in;
136         unsigned char reserved;
137
138         unsigned int data_transfer_length;
139
140         union {
141                 unsigned char cdb[CDB16GENERIC_LENGTH];
142                 unsigned char sense_data[SENSE_BUFFER_SIZE];
143                 unsigned char reserved_array[MAX_DATA_BUF_LEN_WITH_PADDING];
144         };
145 } __attribute((packed));
146
147
148 /*
149  * This structure is sent during the intialization phase to get the different
150  * properties of the channel.
151  */
152 struct vmstorage_channel_properties {
153         unsigned short protocol_version;
154         unsigned char path_id;
155         unsigned char target_id;
156
157         /* Note: port number is only really known on the client side */
158         unsigned int port_number;
159         unsigned int flags;
160         unsigned int max_transfer_bytes;
161
162         /*  This id is unique for each channel and will correspond with */
163         /*  vendor specific data in the inquirydata */
164         unsigned long long unique_id;
165 } __packed;
166
167 /*  This structure is sent during the storage protocol negotiations. */
168 struct vmstorage_protocol_version {
169         /* Major (MSW) and minor (LSW) version numbers. */
170         unsigned short major_minor;
171
172         /*
173          * Revision number is auto-incremented whenever this file is changed
174          * (See FILL_VMSTOR_REVISION macro above).  Mismatch does not
175          * definitely indicate incompatibility--but it does indicate mismatched
176          * builds.
177          */
178         unsigned short revision;
179 } __packed;
180
181 /* Channel Property Flags */
182 #define STORAGE_CHANNEL_REMOVABLE_FLAG          0x1
183 #define STORAGE_CHANNEL_EMULATED_IDE_FLAG       0x2
184
185 struct vstor_packet {
186         /* Requested operation type */
187         enum vstor_packet_operation operation;
188
189         /*  Flags - see below for values */
190         unsigned int flags;
191
192         /* Status of the request returned from the server side. */
193         unsigned int status;
194
195         /* Data payload area */
196         union {
197                 /*
198                  * Structure used to forward SCSI commands from the
199                  * client to the server.
200                  */
201                 struct vmscsi_request vm_srb;
202
203                 /* Structure used to query channel properties. */
204                 struct vmstorage_channel_properties storage_channel_properties;
205
206                 /* Used during version negotiations. */
207                 struct vmstorage_protocol_version version;
208         };
209 } __packed;
210
211 /* Packet flags */
212 /*
213  * This flag indicates that the server should send back a completion for this
214  * packet.
215  */
216 #define REQUEST_COMPLETION_FLAG 0x1
217
218 /*  This is the set of flags that the vsc can set in any packets it sends */
219 #define VSC_LEGAL_FLAGS         (REQUEST_COMPLETION_FLAG)
220
221
222 /* Defines */
223
224 #define STORVSC_MAX_IO_REQUESTS                         128
225
226 /*
227  * In Hyper-V, each port/path/target maps to 1 scsi host adapter.  In
228  * reality, the path/target is not used (ie always set to 0) so our
229  * scsi host adapter essentially has 1 bus with 1 target that contains
230  * up to 256 luns.
231  */
232 #define STORVSC_MAX_LUNS_PER_TARGET                     64
233 #define STORVSC_MAX_TARGETS                             1
234 #define STORVSC_MAX_CHANNELS                            1
235 #define STORVSC_MAX_CMD_LEN                             16
236
237 struct hv_storvsc_request;
238
239 /* Matches Windows-end */
240 enum storvsc_request_type {
241         WRITE_TYPE,
242         READ_TYPE,
243         UNKNOWN_TYPE,
244 };
245
246
247 struct hv_storvsc_request {
248         struct hv_device *device;
249
250         /* Synchronize the request/response if needed */
251         struct completion wait_event;
252
253         unsigned char *sense_buffer;
254         void *context;
255         void (*on_io_completion)(struct hv_storvsc_request *request);
256         struct hv_multipage_buffer data_buffer;
257
258         struct vstor_packet vstor_packet;
259 };
260
261
262 /* A storvsc device is a device object that contains a vmbus channel */
263 struct storvsc_device {
264         struct hv_device *device;
265
266         bool     destroy;
267         bool     drain_notify;
268         atomic_t num_outstanding_req;
269         struct Scsi_Host *host;
270
271         wait_queue_head_t waiting_to_drain;
272
273         /*
274          * Each unique Port/Path/Target represents 1 channel ie scsi
275          * controller. In reality, the pathid, targetid is always 0
276          * and the port is set by us
277          */
278         unsigned int port_number;
279         unsigned char path_id;
280         unsigned char target_id;
281
282         /* Used for vsc/vsp channel reset process */
283         struct hv_storvsc_request init_request;
284         struct hv_storvsc_request reset_request;
285 };
286
287 struct hv_host_device {
288         struct hv_device *dev;
289         struct kmem_cache *request_pool;
290         unsigned int port;
291         unsigned char path;
292         unsigned char target;
293 };
294
295 struct storvsc_cmd_request {
296         struct list_head entry;
297         struct scsi_cmnd *cmd;
298
299         unsigned int bounce_sgl_count;
300         struct scatterlist *bounce_sgl;
301
302         struct hv_storvsc_request request;
303 };
304
305 static inline struct storvsc_device *get_out_stor_device(
306                                         struct hv_device *device)
307 {
308         struct storvsc_device *stor_device;
309
310         stor_device = hv_get_drvdata(device);
311
312         if (stor_device && stor_device->destroy)
313                 stor_device = NULL;
314
315         return stor_device;
316 }
317
318
319 static inline void storvsc_wait_to_drain(struct storvsc_device *dev)
320 {
321         dev->drain_notify = true;
322         wait_event(dev->waiting_to_drain,
323                    atomic_read(&dev->num_outstanding_req) == 0);
324         dev->drain_notify = false;
325 }
326
327 static inline struct storvsc_device *get_in_stor_device(
328                                         struct hv_device *device)
329 {
330         struct storvsc_device *stor_device;
331
332         stor_device = hv_get_drvdata(device);
333
334         if (!stor_device)
335                 goto get_in_err;
336
337         /*
338          * If the device is being destroyed; allow incoming
339          * traffic only to cleanup outstanding requests.
340          */
341
342         if (stor_device->destroy  &&
343                 (atomic_read(&stor_device->num_outstanding_req) == 0))
344                 stor_device = NULL;
345
346 get_in_err:
347         return stor_device;
348
349 }
350
351 static int storvsc_channel_init(struct hv_device *device)
352 {
353         struct storvsc_device *stor_device;
354         struct hv_storvsc_request *request;
355         struct vstor_packet *vstor_packet;
356         int ret, t;
357
358         stor_device = get_out_stor_device(device);
359         if (!stor_device)
360                 return -ENODEV;
361
362         request = &stor_device->init_request;
363         vstor_packet = &request->vstor_packet;
364
365         /*
366          * Now, initiate the vsc/vsp initialization protocol on the open
367          * channel
368          */
369         memset(request, 0, sizeof(struct hv_storvsc_request));
370         init_completion(&request->wait_event);
371         vstor_packet->operation = VSTOR_OPERATION_BEGIN_INITIALIZATION;
372         vstor_packet->flags = REQUEST_COMPLETION_FLAG;
373
374         ret = vmbus_sendpacket(device->channel, vstor_packet,
375                                sizeof(struct vstor_packet),
376                                (unsigned long)request,
377                                VM_PKT_DATA_INBAND,
378                                VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
379         if (ret != 0)
380                 goto cleanup;
381
382         t = wait_for_completion_timeout(&request->wait_event, 5*HZ);
383         if (t == 0) {
384                 ret = -ETIMEDOUT;
385                 goto cleanup;
386         }
387
388         if (vstor_packet->operation != VSTOR_OPERATION_COMPLETE_IO ||
389             vstor_packet->status != 0)
390                 goto cleanup;
391
392
393         /* reuse the packet for version range supported */
394         memset(vstor_packet, 0, sizeof(struct vstor_packet));
395         vstor_packet->operation = VSTOR_OPERATION_QUERY_PROTOCOL_VERSION;
396         vstor_packet->flags = REQUEST_COMPLETION_FLAG;
397
398         vstor_packet->version.major_minor = VMSTOR_PROTOCOL_VERSION_CURRENT;
399         FILL_VMSTOR_REVISION(vstor_packet->version.revision);
400
401         ret = vmbus_sendpacket(device->channel, vstor_packet,
402                                sizeof(struct vstor_packet),
403                                (unsigned long)request,
404                                VM_PKT_DATA_INBAND,
405                                VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
406         if (ret != 0)
407                 goto cleanup;
408
409         t = wait_for_completion_timeout(&request->wait_event, 5*HZ);
410         if (t == 0) {
411                 ret = -ETIMEDOUT;
412                 goto cleanup;
413         }
414
415         if (vstor_packet->operation != VSTOR_OPERATION_COMPLETE_IO ||
416             vstor_packet->status != 0)
417                 goto cleanup;
418
419
420         memset(vstor_packet, 0, sizeof(struct vstor_packet));
421         vstor_packet->operation = VSTOR_OPERATION_QUERY_PROPERTIES;
422         vstor_packet->flags = REQUEST_COMPLETION_FLAG;
423         vstor_packet->storage_channel_properties.port_number =
424                                         stor_device->port_number;
425
426         ret = vmbus_sendpacket(device->channel, vstor_packet,
427                                sizeof(struct vstor_packet),
428                                (unsigned long)request,
429                                VM_PKT_DATA_INBAND,
430                                VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
431
432         if (ret != 0)
433                 goto cleanup;
434
435         t = wait_for_completion_timeout(&request->wait_event, 5*HZ);
436         if (t == 0) {
437                 ret = -ETIMEDOUT;
438                 goto cleanup;
439         }
440
441         if (vstor_packet->operation != VSTOR_OPERATION_COMPLETE_IO ||
442             vstor_packet->status != 0)
443                 goto cleanup;
444
445         stor_device->path_id = vstor_packet->storage_channel_properties.path_id;
446         stor_device->target_id
447                 = vstor_packet->storage_channel_properties.target_id;
448
449         memset(vstor_packet, 0, sizeof(struct vstor_packet));
450         vstor_packet->operation = VSTOR_OPERATION_END_INITIALIZATION;
451         vstor_packet->flags = REQUEST_COMPLETION_FLAG;
452
453         ret = vmbus_sendpacket(device->channel, vstor_packet,
454                                sizeof(struct vstor_packet),
455                                (unsigned long)request,
456                                VM_PKT_DATA_INBAND,
457                                VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
458
459         if (ret != 0)
460                 goto cleanup;
461
462         t = wait_for_completion_timeout(&request->wait_event, 5*HZ);
463         if (t == 0) {
464                 ret = -ETIMEDOUT;
465                 goto cleanup;
466         }
467
468         if (vstor_packet->operation != VSTOR_OPERATION_COMPLETE_IO ||
469             vstor_packet->status != 0)
470                 goto cleanup;
471
472
473 cleanup:
474         return ret;
475 }
476
477 static void storvsc_on_io_completion(struct hv_device *device,
478                                   struct vstor_packet *vstor_packet,
479                                   struct hv_storvsc_request *request)
480 {
481         struct storvsc_device *stor_device;
482         struct vstor_packet *stor_pkt;
483
484         stor_device = hv_get_drvdata(device);
485         stor_pkt = &request->vstor_packet;
486
487         /*
488          * The current SCSI handling on the host side does
489          * not correctly handle:
490          * INQUIRY command with page code parameter set to 0x80
491          * MODE_SENSE command with cmd[2] == 0x1c
492          *
493          * Setup srb and scsi status so this won't be fatal.
494          * We do this so we can distinguish truly fatal failues
495          * (srb status == 0x4) and off-line the device in that case.
496          */
497
498         if ((stor_pkt->vm_srb.cdb[0] == INQUIRY) ||
499                 (stor_pkt->vm_srb.cdb[0] == MODE_SENSE)) {
500                 vstor_packet->vm_srb.scsi_status = 0;
501                 vstor_packet->vm_srb.srb_status = 0x1;
502         }
503
504
505         /* Copy over the status...etc */
506         stor_pkt->vm_srb.scsi_status = vstor_packet->vm_srb.scsi_status;
507         stor_pkt->vm_srb.srb_status = vstor_packet->vm_srb.srb_status;
508         stor_pkt->vm_srb.sense_info_length =
509         vstor_packet->vm_srb.sense_info_length;
510
511         if (vstor_packet->vm_srb.scsi_status != 0 ||
512                 vstor_packet->vm_srb.srb_status != 1){
513                 DPRINT_WARN(STORVSC,
514                             "cmd 0x%x scsi status 0x%x srb status 0x%x\n",
515                             stor_pkt->vm_srb.cdb[0],
516                             vstor_packet->vm_srb.scsi_status,
517                             vstor_packet->vm_srb.srb_status);
518         }
519
520         if ((vstor_packet->vm_srb.scsi_status & 0xFF) == 0x02) {
521                 /* CHECK_CONDITION */
522                 if (vstor_packet->vm_srb.srb_status & 0x80) {
523                         /* autosense data available */
524                         DPRINT_WARN(STORVSC, "storvsc pkt %p autosense data "
525                                     "valid - len %d\n", request,
526                                     vstor_packet->vm_srb.sense_info_length);
527
528                         memcpy(request->sense_buffer,
529                                vstor_packet->vm_srb.sense_data,
530                                vstor_packet->vm_srb.sense_info_length);
531
532                 }
533         }
534
535         stor_pkt->vm_srb.data_transfer_length =
536         vstor_packet->vm_srb.data_transfer_length;
537
538         request->on_io_completion(request);
539
540         if (atomic_dec_and_test(&stor_device->num_outstanding_req) &&
541                 stor_device->drain_notify)
542                 wake_up(&stor_device->waiting_to_drain);
543
544
545 }
546
547 static void storvsc_on_receive(struct hv_device *device,
548                              struct vstor_packet *vstor_packet,
549                              struct hv_storvsc_request *request)
550 {
551         switch (vstor_packet->operation) {
552         case VSTOR_OPERATION_COMPLETE_IO:
553                 storvsc_on_io_completion(device, vstor_packet, request);
554                 break;
555         case VSTOR_OPERATION_REMOVE_DEVICE:
556
557         default:
558                 break;
559         }
560 }
561
562 static void storvsc_on_channel_callback(void *context)
563 {
564         struct hv_device *device = (struct hv_device *)context;
565         struct storvsc_device *stor_device;
566         u32 bytes_recvd;
567         u64 request_id;
568         unsigned char packet[ALIGN(sizeof(struct vstor_packet), 8)];
569         struct hv_storvsc_request *request;
570         int ret;
571
572
573         stor_device = get_in_stor_device(device);
574         if (!stor_device)
575                 return;
576
577         do {
578                 ret = vmbus_recvpacket(device->channel, packet,
579                                        ALIGN(sizeof(struct vstor_packet), 8),
580                                        &bytes_recvd, &request_id);
581                 if (ret == 0 && bytes_recvd > 0) {
582
583                         request = (struct hv_storvsc_request *)
584                                         (unsigned long)request_id;
585
586                         if ((request == &stor_device->init_request) ||
587                             (request == &stor_device->reset_request)) {
588
589                                 memcpy(&request->vstor_packet, packet,
590                                        sizeof(struct vstor_packet));
591                                 complete(&request->wait_event);
592                         } else {
593                                 storvsc_on_receive(device,
594                                                 (struct vstor_packet *)packet,
595                                                 request);
596                         }
597                 } else {
598                         break;
599                 }
600         } while (1);
601
602         return;
603 }
604
605 static int storvsc_connect_to_vsp(struct hv_device *device, u32 ring_size)
606 {
607         struct vmstorage_channel_properties props;
608         int ret;
609
610         memset(&props, 0, sizeof(struct vmstorage_channel_properties));
611
612         /* Open the channel */
613         ret = vmbus_open(device->channel,
614                          ring_size,
615                          ring_size,
616                          (void *)&props,
617                          sizeof(struct vmstorage_channel_properties),
618                          storvsc_on_channel_callback, device);
619
620         if (ret != 0)
621                 return ret;
622
623         ret = storvsc_channel_init(device);
624
625         return ret;
626 }
627
628 static int storvsc_dev_remove(struct hv_device *device)
629 {
630         struct storvsc_device *stor_device;
631         unsigned long flags;
632
633         stor_device = hv_get_drvdata(device);
634
635         spin_lock_irqsave(&device->channel->inbound_lock, flags);
636         stor_device->destroy = true;
637         spin_unlock_irqrestore(&device->channel->inbound_lock, flags);
638
639         /*
640          * At this point, all outbound traffic should be disable. We
641          * only allow inbound traffic (responses) to proceed so that
642          * outstanding requests can be completed.
643          */
644
645         storvsc_wait_to_drain(stor_device);
646
647         /*
648          * Since we have already drained, we don't need to busy wait
649          * as was done in final_release_stor_device()
650          * Note that we cannot set the ext pointer to NULL until
651          * we have drained - to drain the outgoing packets, we need to
652          * allow incoming packets.
653          */
654         spin_lock_irqsave(&device->channel->inbound_lock, flags);
655         hv_set_drvdata(device, NULL);
656         spin_unlock_irqrestore(&device->channel->inbound_lock, flags);
657
658         /* Close the channel */
659         vmbus_close(device->channel);
660
661         kfree(stor_device);
662         return 0;
663 }
664
665 static int storvsc_do_io(struct hv_device *device,
666                               struct hv_storvsc_request *request)
667 {
668         struct storvsc_device *stor_device;
669         struct vstor_packet *vstor_packet;
670         int ret = 0;
671
672         vstor_packet = &request->vstor_packet;
673         stor_device = get_out_stor_device(device);
674
675         if (!stor_device)
676                 return -ENODEV;
677
678
679         request->device  = device;
680
681
682         vstor_packet->flags |= REQUEST_COMPLETION_FLAG;
683
684         vstor_packet->vm_srb.length = sizeof(struct vmscsi_request);
685
686
687         vstor_packet->vm_srb.sense_info_length = SENSE_BUFFER_SIZE;
688
689
690         vstor_packet->vm_srb.data_transfer_length =
691         request->data_buffer.len;
692
693         vstor_packet->operation = VSTOR_OPERATION_EXECUTE_SRB;
694
695         if (request->data_buffer.len) {
696                 ret = vmbus_sendpacket_multipagebuffer(device->channel,
697                                 &request->data_buffer,
698                                 vstor_packet,
699                                 sizeof(struct vstor_packet),
700                                 (unsigned long)request);
701         } else {
702                 ret = vmbus_sendpacket(device->channel, vstor_packet,
703                                sizeof(struct vstor_packet),
704                                (unsigned long)request,
705                                VM_PKT_DATA_INBAND,
706                                VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
707         }
708
709         if (ret != 0)
710                 return ret;
711
712         atomic_inc(&stor_device->num_outstanding_req);
713
714         return ret;
715 }
716
717 static void storvsc_get_ide_info(struct hv_device *dev, int *target, int *path)
718 {
719         *target =
720                 dev->dev_instance.b[5] << 8 | dev->dev_instance.b[4];
721
722         *path =
723                 dev->dev_instance.b[3] << 24 |
724                 dev->dev_instance.b[2] << 16 |
725                 dev->dev_instance.b[1] << 8  | dev->dev_instance.b[0];
726 }
727
728
729 static int storvsc_device_alloc(struct scsi_device *sdevice)
730 {
731         /*
732          * This enables luns to be located sparsely. Otherwise, we may not
733          * discovered them.
734          */
735         sdevice->sdev_bflags |= BLIST_SPARSELUN | BLIST_LARGELUN;
736         return 0;
737 }
738
739 static int storvsc_merge_bvec(struct request_queue *q,
740                               struct bvec_merge_data *bmd, struct bio_vec *bvec)
741 {
742         /* checking done by caller. */
743         return bvec->bv_len;
744 }
745
746 static int storvsc_device_configure(struct scsi_device *sdevice)
747 {
748         scsi_adjust_queue_depth(sdevice, MSG_SIMPLE_TAG,
749                                 STORVSC_MAX_IO_REQUESTS);
750
751         blk_queue_max_segment_size(sdevice->request_queue, PAGE_SIZE);
752
753         blk_queue_merge_bvec(sdevice->request_queue, storvsc_merge_bvec);
754
755         blk_queue_bounce_limit(sdevice->request_queue, BLK_BOUNCE_ANY);
756
757         return 0;
758 }
759
760 static void destroy_bounce_buffer(struct scatterlist *sgl,
761                                   unsigned int sg_count)
762 {
763         int i;
764         struct page *page_buf;
765
766         for (i = 0; i < sg_count; i++) {
767                 page_buf = sg_page((&sgl[i]));
768                 if (page_buf != NULL)
769                         __free_page(page_buf);
770         }
771
772         kfree(sgl);
773 }
774
775 static int do_bounce_buffer(struct scatterlist *sgl, unsigned int sg_count)
776 {
777         int i;
778
779         /* No need to check */
780         if (sg_count < 2)
781                 return -1;
782
783         /* We have at least 2 sg entries */
784         for (i = 0; i < sg_count; i++) {
785                 if (i == 0) {
786                         /* make sure 1st one does not have hole */
787                         if (sgl[i].offset + sgl[i].length != PAGE_SIZE)
788                                 return i;
789                 } else if (i == sg_count - 1) {
790                         /* make sure last one does not have hole */
791                         if (sgl[i].offset != 0)
792                                 return i;
793                 } else {
794                         /* make sure no hole in the middle */
795                         if (sgl[i].length != PAGE_SIZE || sgl[i].offset != 0)
796                                 return i;
797                 }
798         }
799         return -1;
800 }
801
802 static struct scatterlist *create_bounce_buffer(struct scatterlist *sgl,
803                                                 unsigned int sg_count,
804                                                 unsigned int len)
805 {
806         int i;
807         int num_pages;
808         struct scatterlist *bounce_sgl;
809         struct page *page_buf;
810
811         num_pages = ALIGN(len, PAGE_SIZE) >> PAGE_SHIFT;
812
813         bounce_sgl = kcalloc(num_pages, sizeof(struct scatterlist), GFP_ATOMIC);
814         if (!bounce_sgl)
815                 return NULL;
816
817         for (i = 0; i < num_pages; i++) {
818                 page_buf = alloc_page(GFP_ATOMIC);
819                 if (!page_buf)
820                         goto cleanup;
821                 sg_set_page(&bounce_sgl[i], page_buf, 0, 0);
822         }
823
824         return bounce_sgl;
825
826 cleanup:
827         destroy_bounce_buffer(bounce_sgl, num_pages);
828         return NULL;
829 }
830
831
832 /* Assume the original sgl has enough room */
833 static unsigned int copy_from_bounce_buffer(struct scatterlist *orig_sgl,
834                                             struct scatterlist *bounce_sgl,
835                                             unsigned int orig_sgl_count)
836 {
837         int i;
838         int j = 0;
839         unsigned long src, dest;
840         unsigned int srclen, destlen, copylen;
841         unsigned int total_copied = 0;
842         unsigned long bounce_addr = 0;
843         unsigned long dest_addr = 0;
844         unsigned long flags;
845
846         local_irq_save(flags);
847
848         for (i = 0; i < orig_sgl_count; i++) {
849                 dest_addr = (unsigned long)kmap_atomic(sg_page((&orig_sgl[i])),
850                                         KM_IRQ0) + orig_sgl[i].offset;
851                 dest = dest_addr;
852                 destlen = orig_sgl[i].length;
853
854                 if (bounce_addr == 0)
855                         bounce_addr =
856                         (unsigned long)kmap_atomic(sg_page((&bounce_sgl[j])),
857                                                         KM_IRQ0);
858
859                 while (destlen) {
860                         src = bounce_addr + bounce_sgl[j].offset;
861                         srclen = bounce_sgl[j].length - bounce_sgl[j].offset;
862
863                         copylen = min(srclen, destlen);
864                         memcpy((void *)dest, (void *)src, copylen);
865
866                         total_copied += copylen;
867                         bounce_sgl[j].offset += copylen;
868                         destlen -= copylen;
869                         dest += copylen;
870
871                         if (bounce_sgl[j].offset == bounce_sgl[j].length) {
872                                 /* full */
873                                 kunmap_atomic((void *)bounce_addr, KM_IRQ0);
874                                 j++;
875
876                                 /* if we need to use another bounce buffer */
877                                 if (destlen || i != orig_sgl_count - 1)
878                                         bounce_addr =
879                                         (unsigned long)kmap_atomic(
880                                         sg_page((&bounce_sgl[j])), KM_IRQ0);
881                         } else if (destlen == 0 && i == orig_sgl_count - 1) {
882                                 /* unmap the last bounce that is < PAGE_SIZE */
883                                 kunmap_atomic((void *)bounce_addr, KM_IRQ0);
884                         }
885                 }
886
887                 kunmap_atomic((void *)(dest_addr - orig_sgl[i].offset),
888                               KM_IRQ0);
889         }
890
891         local_irq_restore(flags);
892
893         return total_copied;
894 }
895
896
897 /* Assume the bounce_sgl has enough room ie using the create_bounce_buffer() */
898 static unsigned int copy_to_bounce_buffer(struct scatterlist *orig_sgl,
899                                           struct scatterlist *bounce_sgl,
900                                           unsigned int orig_sgl_count)
901 {
902         int i;
903         int j = 0;
904         unsigned long src, dest;
905         unsigned int srclen, destlen, copylen;
906         unsigned int total_copied = 0;
907         unsigned long bounce_addr = 0;
908         unsigned long src_addr = 0;
909         unsigned long flags;
910
911         local_irq_save(flags);
912
913         for (i = 0; i < orig_sgl_count; i++) {
914                 src_addr = (unsigned long)kmap_atomic(sg_page((&orig_sgl[i])),
915                                 KM_IRQ0) + orig_sgl[i].offset;
916                 src = src_addr;
917                 srclen = orig_sgl[i].length;
918
919                 if (bounce_addr == 0)
920                         bounce_addr =
921                         (unsigned long)kmap_atomic(sg_page((&bounce_sgl[j])),
922                                                 KM_IRQ0);
923
924                 while (srclen) {
925                         /* assume bounce offset always == 0 */
926                         dest = bounce_addr + bounce_sgl[j].length;
927                         destlen = PAGE_SIZE - bounce_sgl[j].length;
928
929                         copylen = min(srclen, destlen);
930                         memcpy((void *)dest, (void *)src, copylen);
931
932                         total_copied += copylen;
933                         bounce_sgl[j].length += copylen;
934                         srclen -= copylen;
935                         src += copylen;
936
937                         if (bounce_sgl[j].length == PAGE_SIZE) {
938                                 /* full..move to next entry */
939                                 kunmap_atomic((void *)bounce_addr, KM_IRQ0);
940                                 j++;
941
942                                 /* if we need to use another bounce buffer */
943                                 if (srclen || i != orig_sgl_count - 1)
944                                         bounce_addr =
945                                         (unsigned long)kmap_atomic(
946                                         sg_page((&bounce_sgl[j])), KM_IRQ0);
947
948                         } else if (srclen == 0 && i == orig_sgl_count - 1) {
949                                 /* unmap the last bounce that is < PAGE_SIZE */
950                                 kunmap_atomic((void *)bounce_addr, KM_IRQ0);
951                         }
952                 }
953
954                 kunmap_atomic((void *)(src_addr - orig_sgl[i].offset), KM_IRQ0);
955         }
956
957         local_irq_restore(flags);
958
959         return total_copied;
960 }
961
962
963 static int storvsc_remove(struct hv_device *dev)
964 {
965         struct storvsc_device *stor_device = hv_get_drvdata(dev);
966         struct Scsi_Host *host = stor_device->host;
967         struct hv_host_device *host_dev =
968                         (struct hv_host_device *)host->hostdata;
969
970         scsi_remove_host(host);
971
972         scsi_host_put(host);
973
974         storvsc_dev_remove(dev);
975         if (host_dev->request_pool) {
976                 kmem_cache_destroy(host_dev->request_pool);
977                 host_dev->request_pool = NULL;
978         }
979         return 0;
980 }
981
982
983 static int storvsc_get_chs(struct scsi_device *sdev, struct block_device * bdev,
984                            sector_t capacity, int *info)
985 {
986         sector_t nsect = capacity;
987         sector_t cylinders = nsect;
988         int heads, sectors_pt;
989
990         /*
991          * We are making up these values; let us keep it simple.
992          */
993         heads = 0xff;
994         sectors_pt = 0x3f;      /* Sectors per track */
995         sector_div(cylinders, heads * sectors_pt);
996         if ((sector_t)(cylinders + 1) * heads * sectors_pt < nsect)
997                 cylinders = 0xffff;
998
999         info[0] = heads;
1000         info[1] = sectors_pt;
1001         info[2] = (int)cylinders;
1002
1003         return 0;
1004 }
1005
1006 static int storvsc_host_reset(struct hv_device *device)
1007 {
1008         struct storvsc_device *stor_device;
1009         struct hv_storvsc_request *request;
1010         struct vstor_packet *vstor_packet;
1011         int ret, t;
1012
1013
1014         stor_device = get_out_stor_device(device);
1015         if (!stor_device)
1016                 return -ENODEV;
1017
1018         request = &stor_device->reset_request;
1019         vstor_packet = &request->vstor_packet;
1020
1021         init_completion(&request->wait_event);
1022
1023         vstor_packet->operation = VSTOR_OPERATION_RESET_BUS;
1024         vstor_packet->flags = REQUEST_COMPLETION_FLAG;
1025         vstor_packet->vm_srb.path_id = stor_device->path_id;
1026
1027         ret = vmbus_sendpacket(device->channel, vstor_packet,
1028                                sizeof(struct vstor_packet),
1029                                (unsigned long)&stor_device->reset_request,
1030                                VM_PKT_DATA_INBAND,
1031                                VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
1032         if (ret != 0)
1033                 goto cleanup;
1034
1035         t = wait_for_completion_timeout(&request->wait_event, 5*HZ);
1036         if (t == 0) {
1037                 ret = -ETIMEDOUT;
1038                 goto cleanup;
1039         }
1040
1041
1042         /*
1043          * At this point, all outstanding requests in the adapter
1044          * should have been flushed out and return to us
1045          */
1046
1047 cleanup:
1048         return ret;
1049 }
1050
1051
1052 /*
1053  * storvsc_host_reset_handler - Reset the scsi HBA
1054  */
1055 static int storvsc_host_reset_handler(struct scsi_cmnd *scmnd)
1056 {
1057         int ret;
1058         struct hv_host_device *host_dev =
1059                 (struct hv_host_device *)scmnd->device->host->hostdata;
1060         struct hv_device *dev = host_dev->dev;
1061
1062         ret = storvsc_host_reset(dev);
1063         if (ret != 0)
1064                 return ret;
1065
1066         return ret;
1067 }
1068
1069
1070 /*
1071  * storvsc_command_completion - Command completion processing
1072  */
1073 static void storvsc_command_completion(struct hv_storvsc_request *request)
1074 {
1075         struct storvsc_cmd_request *cmd_request =
1076                 (struct storvsc_cmd_request *)request->context;
1077         struct scsi_cmnd *scmnd = cmd_request->cmd;
1078         struct hv_host_device *host_dev =
1079                 (struct hv_host_device *)scmnd->device->host->hostdata;
1080         void (*scsi_done_fn)(struct scsi_cmnd *);
1081         struct scsi_sense_hdr sense_hdr;
1082         struct vmscsi_request *vm_srb;
1083
1084         vm_srb = &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                         destroy_bounce_buffer(cmd_request->bounce_sgl,
1091                                         cmd_request->bounce_sgl_count);
1092                 }
1093         }
1094
1095         /*
1096          * If there is an error; offline the device since all
1097          * error recovery strategies would have already been
1098          * deployed on the host side.
1099          */
1100         if (vm_srb->srb_status == 0x4)
1101                 scmnd->result = DID_TARGET_FAILURE << 16;
1102         else
1103                 scmnd->result = vm_srb->scsi_status;
1104
1105         if (scmnd->result) {
1106                 if (scsi_normalize_sense(scmnd->sense_buffer,
1107                                 SCSI_SENSE_BUFFERSIZE, &sense_hdr))
1108                         scsi_print_sense_hdr("storvsc", &sense_hdr);
1109         }
1110
1111         scsi_set_resid(scmnd,
1112                 request->data_buffer.len -
1113                 vm_srb->data_transfer_length);
1114
1115         scsi_done_fn = scmnd->scsi_done;
1116
1117         scmnd->host_scribble = NULL;
1118         scmnd->scsi_done = NULL;
1119
1120         scsi_done_fn(scmnd);
1121
1122         kmem_cache_free(host_dev->request_pool, cmd_request);
1123 }
1124
1125 static bool storvsc_check_scsi_cmd(struct scsi_cmnd *scmnd)
1126 {
1127         bool allowed = true;
1128         u8 scsi_op = scmnd->cmnd[0];
1129
1130         switch (scsi_op) {
1131                 /* smartd sends this command, which will offline the device */
1132                 case SET_WINDOW:
1133                         scmnd->result = DID_ERROR << 16;
1134                         allowed = false;
1135                         break;
1136                 default:
1137                         break;
1138         }
1139         return allowed;
1140 }
1141
1142 /*
1143  * storvsc_queuecommand - Initiate command processing
1144  */
1145 static int storvsc_queuecommand_lck(struct scsi_cmnd *scmnd,
1146                                 void (*done)(struct scsi_cmnd *))
1147 {
1148         int ret;
1149         struct hv_host_device *host_dev =
1150                 (struct hv_host_device *)scmnd->device->host->hostdata;
1151         struct hv_device *dev = host_dev->dev;
1152         struct hv_storvsc_request *request;
1153         struct storvsc_cmd_request *cmd_request;
1154         unsigned int request_size = 0;
1155         int i;
1156         struct scatterlist *sgl;
1157         unsigned int sg_count = 0;
1158         struct vmscsi_request *vm_srb;
1159
1160         if (storvsc_check_scsi_cmd(scmnd) == false) {
1161                 done(scmnd);
1162                 return 0;
1163         }
1164
1165         /* If retrying, no need to prep the cmd */
1166         if (scmnd->host_scribble) {
1167
1168                 cmd_request =
1169                         (struct storvsc_cmd_request *)scmnd->host_scribble;
1170
1171                 goto retry_request;
1172         }
1173
1174         scmnd->scsi_done = done;
1175
1176         request_size = sizeof(struct storvsc_cmd_request);
1177
1178         cmd_request = kmem_cache_zalloc(host_dev->request_pool,
1179                                        GFP_ATOMIC);
1180         if (!cmd_request) {
1181                 scmnd->scsi_done = NULL;
1182                 return SCSI_MLQUEUE_DEVICE_BUSY;
1183         }
1184
1185         /* Setup the cmd request */
1186         cmd_request->bounce_sgl_count = 0;
1187         cmd_request->bounce_sgl = NULL;
1188         cmd_request->cmd = scmnd;
1189
1190         scmnd->host_scribble = (unsigned char *)cmd_request;
1191
1192         request = &cmd_request->request;
1193         vm_srb = &request->vstor_packet.vm_srb;
1194
1195
1196         /* Build the SRB */
1197         switch (scmnd->sc_data_direction) {
1198         case DMA_TO_DEVICE:
1199                 vm_srb->data_in = WRITE_TYPE;
1200                 break;
1201         case DMA_FROM_DEVICE:
1202                 vm_srb->data_in = READ_TYPE;
1203                 break;
1204         default:
1205                 vm_srb->data_in = UNKNOWN_TYPE;
1206                 break;
1207         }
1208
1209         request->on_io_completion = storvsc_command_completion;
1210         request->context = cmd_request;/* scmnd; */
1211
1212         vm_srb->port_number = host_dev->port;
1213         vm_srb->path_id = scmnd->device->channel;
1214         vm_srb->target_id = scmnd->device->id;
1215         vm_srb->lun = scmnd->device->lun;
1216
1217         vm_srb->cdb_length = scmnd->cmd_len;
1218
1219         memcpy(vm_srb->cdb, scmnd->cmnd, vm_srb->cdb_length);
1220
1221         request->sense_buffer = scmnd->sense_buffer;
1222
1223
1224         request->data_buffer.len = scsi_bufflen(scmnd);
1225         if (scsi_sg_count(scmnd)) {
1226                 sgl = (struct scatterlist *)scsi_sglist(scmnd);
1227                 sg_count = scsi_sg_count(scmnd);
1228
1229                 /* check if we need to bounce the sgl */
1230                 if (do_bounce_buffer(sgl, scsi_sg_count(scmnd)) != -1) {
1231                         cmd_request->bounce_sgl =
1232                                 create_bounce_buffer(sgl, scsi_sg_count(scmnd),
1233                                                      scsi_bufflen(scmnd));
1234                         if (!cmd_request->bounce_sgl) {
1235                                 scmnd->scsi_done = NULL;
1236                                 scmnd->host_scribble = NULL;
1237                                 kmem_cache_free(host_dev->request_pool,
1238                                                 cmd_request);
1239
1240                                 return SCSI_MLQUEUE_HOST_BUSY;
1241                         }
1242
1243                         cmd_request->bounce_sgl_count =
1244                                 ALIGN(scsi_bufflen(scmnd), PAGE_SIZE) >>
1245                                         PAGE_SHIFT;
1246
1247                         if (vm_srb->data_in == WRITE_TYPE)
1248                                 copy_to_bounce_buffer(sgl,
1249                                         cmd_request->bounce_sgl,
1250                                         scsi_sg_count(scmnd));
1251
1252                         sgl = cmd_request->bounce_sgl;
1253                         sg_count = cmd_request->bounce_sgl_count;
1254                 }
1255
1256                 request->data_buffer.offset = sgl[0].offset;
1257
1258                 for (i = 0; i < sg_count; i++)
1259                         request->data_buffer.pfn_array[i] =
1260                                 page_to_pfn(sg_page((&sgl[i])));
1261
1262         } else if (scsi_sglist(scmnd)) {
1263                 request->data_buffer.offset =
1264                         virt_to_phys(scsi_sglist(scmnd)) & (PAGE_SIZE-1);
1265                 request->data_buffer.pfn_array[0] =
1266                         virt_to_phys(scsi_sglist(scmnd)) >> PAGE_SHIFT;
1267         }
1268
1269 retry_request:
1270         /* Invokes the vsc to start an IO */
1271         ret = storvsc_do_io(dev, &cmd_request->request);
1272
1273         if (ret == -EAGAIN) {
1274                 /* no more space */
1275
1276                 if (cmd_request->bounce_sgl_count)
1277                         destroy_bounce_buffer(cmd_request->bounce_sgl,
1278                                         cmd_request->bounce_sgl_count);
1279
1280                 kmem_cache_free(host_dev->request_pool, cmd_request);
1281
1282                 scmnd->scsi_done = NULL;
1283                 scmnd->host_scribble = NULL;
1284
1285                 ret = SCSI_MLQUEUE_DEVICE_BUSY;
1286         }
1287
1288         return ret;
1289 }
1290
1291 static DEF_SCSI_QCMD(storvsc_queuecommand)
1292
1293
1294 /* Scsi driver */
1295 static struct scsi_host_template scsi_driver = {
1296         .module =               THIS_MODULE,
1297         .name =                 "storvsc_host_t",
1298         .bios_param =           storvsc_get_chs,
1299         .queuecommand =         storvsc_queuecommand,
1300         .eh_host_reset_handler =        storvsc_host_reset_handler,
1301         .slave_alloc =          storvsc_device_alloc,
1302         .slave_configure =      storvsc_device_configure,
1303         .cmd_per_lun =          1,
1304         /* 64 max_queue * 1 target */
1305         .can_queue =            STORVSC_MAX_IO_REQUESTS*STORVSC_MAX_TARGETS,
1306         .this_id =              -1,
1307         /* no use setting to 0 since ll_blk_rw reset it to 1 */
1308         /* currently 32 */
1309         .sg_tablesize =         MAX_MULTIPAGE_BUFFER_COUNT,
1310         /*
1311          * ENABLE_CLUSTERING allows mutiple physically contig bio_vecs to merge
1312          * into 1 sg element. If set, we must limit the max_segment_size to
1313          * PAGE_SIZE, otherwise we may get 1 sg element that represents
1314          * multiple
1315          */
1316         /* physically contig pfns (ie sg[x].length > PAGE_SIZE). */
1317         .use_clustering =       ENABLE_CLUSTERING,
1318         /* Make sure we dont get a sg segment crosses a page boundary */
1319         .dma_boundary =         PAGE_SIZE-1,
1320 };
1321
1322 enum {
1323         SCSI_GUID,
1324         IDE_GUID,
1325 };
1326
1327 static const struct hv_vmbus_device_id id_table[] = {
1328         /* SCSI guid */
1329         { VMBUS_DEVICE(0xd9, 0x63, 0x61, 0xba, 0xa1, 0x04, 0x29, 0x4d,
1330                        0xb6, 0x05, 0x72, 0xe2, 0xff, 0xb1, 0xdc, 0x7f)
1331           .driver_data = SCSI_GUID },
1332         /* IDE guid */
1333         { VMBUS_DEVICE(0x32, 0x26, 0x41, 0x32, 0xcb, 0x86, 0xa2, 0x44,
1334                        0x9b, 0x5c, 0x50, 0xd1, 0x41, 0x73, 0x54, 0xf5)
1335           .driver_data = IDE_GUID },
1336         { },
1337 };
1338
1339 MODULE_DEVICE_TABLE(vmbus, id_table);
1340
1341
1342 /*
1343  * storvsc_probe - Add a new device for this driver
1344  */
1345
1346 static int storvsc_probe(struct hv_device *device,
1347                         const struct hv_vmbus_device_id *dev_id)
1348 {
1349         int ret;
1350         struct Scsi_Host *host;
1351         struct hv_host_device *host_dev;
1352         bool dev_is_ide = ((dev_id->driver_data == IDE_GUID) ? true : false);
1353         int path = 0;
1354         int target = 0;
1355         struct storvsc_device *stor_device;
1356
1357         host = scsi_host_alloc(&scsi_driver,
1358                                sizeof(struct hv_host_device));
1359         if (!host)
1360                 return -ENOMEM;
1361
1362         host_dev = (struct hv_host_device *)host->hostdata;
1363         memset(host_dev, 0, sizeof(struct hv_host_device));
1364
1365         host_dev->port = host->host_no;
1366         host_dev->dev = device;
1367
1368         host_dev->request_pool =
1369                                 kmem_cache_create(dev_name(&device->device),
1370                                         sizeof(struct storvsc_cmd_request), 0,
1371                                         SLAB_HWCACHE_ALIGN, NULL);
1372
1373         if (!host_dev->request_pool) {
1374                 scsi_host_put(host);
1375                 return -ENOMEM;
1376         }
1377
1378         stor_device = kzalloc(sizeof(struct storvsc_device), GFP_KERNEL);
1379         if (!stor_device) {
1380                 kmem_cache_destroy(host_dev->request_pool);
1381                 scsi_host_put(host);
1382                 return -ENOMEM;
1383         }
1384
1385         stor_device->destroy = false;
1386         init_waitqueue_head(&stor_device->waiting_to_drain);
1387         stor_device->device = device;
1388         stor_device->host = host;
1389         hv_set_drvdata(device, stor_device);
1390
1391         stor_device->port_number = host->host_no;
1392         ret = storvsc_connect_to_vsp(device, storvsc_ringbuffer_size);
1393         if (ret) {
1394                 kmem_cache_destroy(host_dev->request_pool);
1395                 scsi_host_put(host);
1396                 kfree(stor_device);
1397                 return ret;
1398         }
1399
1400         if (dev_is_ide)
1401                 storvsc_get_ide_info(device, &target, &path);
1402
1403         host_dev->path = stor_device->path_id;
1404         host_dev->target = stor_device->target_id;
1405
1406         /* max # of devices per target */
1407         host->max_lun = STORVSC_MAX_LUNS_PER_TARGET;
1408         /* max # of targets per channel */
1409         host->max_id = STORVSC_MAX_TARGETS;
1410         /* max # of channels */
1411         host->max_channel = STORVSC_MAX_CHANNELS - 1;
1412         /* max cmd length */
1413         host->max_cmd_len = STORVSC_MAX_CMD_LEN;
1414
1415         /* Register the HBA and start the scsi bus scan */
1416         ret = scsi_add_host(host, &device->device);
1417         if (ret != 0)
1418                 goto err_out;
1419
1420         if (!dev_is_ide) {
1421                 scsi_scan_host(host);
1422                 return 0;
1423         }
1424         ret = scsi_add_device(host, 0, target, 0);
1425         if (ret) {
1426                 scsi_remove_host(host);
1427                 goto err_out;
1428         }
1429         return 0;
1430
1431 err_out:
1432         storvsc_dev_remove(device);
1433         kmem_cache_destroy(host_dev->request_pool);
1434         scsi_host_put(host);
1435         return -ENODEV;
1436 }
1437
1438 /* The one and only one */
1439
1440 static struct hv_driver storvsc_drv = {
1441         .name = "storvsc",
1442         .id_table = id_table,
1443         .probe = storvsc_probe,
1444         .remove = storvsc_remove,
1445 };
1446
1447 static int __init storvsc_drv_init(void)
1448 {
1449         u32 max_outstanding_req_per_channel;
1450
1451         /*
1452          * Divide the ring buffer data size (which is 1 page less
1453          * than the ring buffer size since that page is reserved for
1454          * the ring buffer indices) by the max request size (which is
1455          * vmbus_channel_packet_multipage_buffer + struct vstor_packet + u64)
1456          */
1457         max_outstanding_req_per_channel =
1458                 ((storvsc_ringbuffer_size - PAGE_SIZE) /
1459                 ALIGN(MAX_MULTIPAGE_BUFFER_PACKET +
1460                 sizeof(struct vstor_packet) + sizeof(u64),
1461                 sizeof(u64)));
1462
1463         if (max_outstanding_req_per_channel <
1464             STORVSC_MAX_IO_REQUESTS)
1465                 return -EINVAL;
1466
1467         return vmbus_driver_register(&storvsc_drv);
1468 }
1469
1470 static void __exit storvsc_drv_exit(void)
1471 {
1472         vmbus_driver_unregister(&storvsc_drv);
1473 }
1474
1475 MODULE_LICENSE("GPL");
1476 MODULE_VERSION(HV_DRV_VERSION);
1477 MODULE_DESCRIPTION("Microsoft Hyper-V virtual storage driver");
1478 module_init(storvsc_drv_init);
1479 module_exit(storvsc_drv_exit);