/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#include <linux/init.h>
 23#include <linux/slab.h>
 24#include <linux/module.h>
 25#include <linux/device.h>
 26#include <linux/blkdev.h>
 27#include <linux/dmi.h>
 28#include <scsi/scsi.h>
 29#include <scsi/scsi_cmnd.h>
 30#include <scsi/scsi_host.h>
 31#include <scsi/scsi_device.h>
 32#include <scsi/scsi_tcq.h>
 33#include <scsi/scsi_eh.h>
 34#include <scsi/scsi_devinfo.h>
 35#include <scsi/scsi_dbg.h>
 36
 37#include "hyperv.h"
 38#include "hyperv_storage.h"
 39
 40static int storvsc_ringbuffer_size = STORVSC_RING_BUFFER_SIZE;
 41
 42module_param(storvsc_ringbuffer_size, int, S_IRUGO);
 43MODULE_PARM_DESC(storvsc_ringbuffer_size, "Ring buffer size (bytes)");
 44
 45static const char *driver_name = "storvsc";
 46
 47/* {ba6163d9-04a1-4d29-b605-72e2ffb1dc7f} */
 48static const struct hv_guid stor_vsci_device_type = {
 49	.data = {
 50		0xd9, 0x63, 0x61, 0xba, 0xa1, 0x04, 0x29, 0x4d,
 51		0xb6, 0x05, 0x72, 0xe2, 0xff, 0xb1, 0xdc, 0x7f
 52	}
 53};
 54
 55struct hv_host_device {
 56	struct hv_device *dev;
 57	struct kmem_cache *request_pool;
 58	unsigned int port;
 59	unsigned char path;
 60	unsigned char target;
 61};
 62
 63struct storvsc_cmd_request {
 64	struct list_head entry;
 65	struct scsi_cmnd *cmd;
 66
 67	unsigned int bounce_sgl_count;
 68	struct scatterlist *bounce_sgl;
 69
 70	struct hv_storvsc_request request;
 71};
 72
 73
 74static int storvsc_device_alloc(struct scsi_device *sdevice)
 75{
 76	/*
 77	 * This enables luns to be located sparsely. Otherwise, we may not
 78	 * discovered them.
 79	 */
 80	sdevice->sdev_bflags |= BLIST_SPARSELUN | BLIST_LARGELUN;
 81	return 0;
 82}
 83
 84static int storvsc_merge_bvec(struct request_queue *q,
 85			      struct bvec_merge_data *bmd, struct bio_vec *bvec)
 86{
 87	/* checking done by caller. */
 88	return bvec->bv_len;
 89}
 90
 91static int storvsc_device_configure(struct scsi_device *sdevice)
 92{
 93	scsi_adjust_queue_depth(sdevice, MSG_SIMPLE_TAG,
 94				STORVSC_MAX_IO_REQUESTS);
 95
 96	blk_queue_max_segment_size(sdevice->request_queue, PAGE_SIZE);
 97
 98	blk_queue_merge_bvec(sdevice->request_queue, storvsc_merge_bvec);
 99
100	blk_queue_bounce_limit(sdevice->request_queue, BLK_BOUNCE_ANY);
101
102	return 0;
103}
104
105static void destroy_bounce_buffer(struct scatterlist *sgl,
106				  unsigned int sg_count)
107{
108	int i;
109	struct page *page_buf;
110
111	for (i = 0; i < sg_count; i++) {
112		page_buf = sg_page((&sgl[i]));
113		if (page_buf != NULL)
114			__free_page(page_buf);
115	}
116
117	kfree(sgl);
118}
119
120static int do_bounce_buffer(struct scatterlist *sgl, unsigned int sg_count)
121{
122	int i;
123
124	/* No need to check */
125	if (sg_count < 2)
126		return -1;
127
128	/* We have at least 2 sg entries */
129	for (i = 0; i < sg_count; i++) {
130		if (i == 0) {
131			/* make sure 1st one does not have hole */
132			if (sgl[i].offset + sgl[i].length != PAGE_SIZE)
133				return i;
134		} else if (i == sg_count - 1) {
135			/* make sure last one does not have hole */
136			if (sgl[i].offset != 0)
137				return i;
138		} else {
139			/* make sure no hole in the middle */
140			if (sgl[i].length != PAGE_SIZE || sgl[i].offset != 0)
141				return i;
142		}
143	}
144	return -1;
145}
146
147static struct scatterlist *create_bounce_buffer(struct scatterlist *sgl,
148						unsigned int sg_count,
149						unsigned int len)
150{
151	int i;
152	int num_pages;
153	struct scatterlist *bounce_sgl;
154	struct page *page_buf;
155
156	num_pages = ALIGN(len, PAGE_SIZE) >> PAGE_SHIFT;
157
158	bounce_sgl = kcalloc(num_pages, sizeof(struct scatterlist), GFP_ATOMIC);
159	if (!bounce_sgl)
160		return NULL;
161
162	for (i = 0; i < num_pages; i++) {
163		page_buf = alloc_page(GFP_ATOMIC);
164		if (!page_buf)
165			goto cleanup;
166		sg_set_page(&bounce_sgl[i], page_buf, 0, 0);
167	}
168
169	return bounce_sgl;
170
171cleanup:
172	destroy_bounce_buffer(bounce_sgl, num_pages);
173	return NULL;
174}
175
176
177/* Assume the original sgl has enough room */
178static unsigned int copy_from_bounce_buffer(struct scatterlist *orig_sgl,
179					    struct scatterlist *bounce_sgl,
180					    unsigned int orig_sgl_count)
181{
182	int i;
183	int j = 0;
184	unsigned long src, dest;
185	unsigned int srclen, destlen, copylen;
186	unsigned int total_copied = 0;
187	unsigned long bounce_addr = 0;
188	unsigned long dest_addr = 0;
189	unsigned long flags;
190
191	local_irq_save(flags);
192
193	for (i = 0; i < orig_sgl_count; i++) {
194		dest_addr = (unsigned long)kmap_atomic(sg_page((&orig_sgl[i])),
195					KM_IRQ0) + orig_sgl[i].offset;
196		dest = dest_addr;
197		destlen = orig_sgl[i].length;
198
199		if (bounce_addr == 0)
200			bounce_addr =
201			(unsigned long)kmap_atomic(sg_page((&bounce_sgl[j])),
202							KM_IRQ0);
203
204		while (destlen) {
205			src = bounce_addr + bounce_sgl[j].offset;
206			srclen = bounce_sgl[j].length - bounce_sgl[j].offset;
207
208			copylen = min(srclen, destlen);
209			memcpy((void *)dest, (void *)src, copylen);
210
211			total_copied += copylen;
212			bounce_sgl[j].offset += copylen;
213			destlen -= copylen;
214			dest += copylen;
215
216			if (bounce_sgl[j].offset == bounce_sgl[j].length) {
217				/* full */
218				kunmap_atomic((void *)bounce_addr, KM_IRQ0);
219				j++;
220
221				/* if we need to use another bounce buffer */
222				if (destlen || i != orig_sgl_count - 1)
223					bounce_addr =
224					(unsigned long)kmap_atomic(
225					sg_page((&bounce_sgl[j])), KM_IRQ0);
226			} else if (destlen == 0 && i == orig_sgl_count - 1) {
227				/* unmap the last bounce that is < PAGE_SIZE */
228				kunmap_atomic((void *)bounce_addr, KM_IRQ0);
229			}
230		}
231
232		kunmap_atomic((void *)(dest_addr - orig_sgl[i].offset),
233			      KM_IRQ0);
234	}
235
236	local_irq_restore(flags);
237
238	return total_copied;
239}
240
241
242/* Assume the bounce_sgl has enough room ie using the create_bounce_buffer() */
243static unsigned int copy_to_bounce_buffer(struct scatterlist *orig_sgl,
244					  struct scatterlist *bounce_sgl,
245					  unsigned int orig_sgl_count)
246{
247	int i;
248	int j = 0;
249	unsigned long src, dest;
250	unsigned int srclen, destlen, copylen;
251	unsigned int total_copied = 0;
252	unsigned long bounce_addr = 0;
253	unsigned long src_addr = 0;
254	unsigned long flags;
255
256	local_irq_save(flags);
257
258	for (i = 0; i < orig_sgl_count; i++) {
259		src_addr = (unsigned long)kmap_atomic(sg_page((&orig_sgl[i])),
260				KM_IRQ0) + orig_sgl[i].offset;
261		src = src_addr;
262		srclen = orig_sgl[i].length;
263
264		if (bounce_addr == 0)
265			bounce_addr =
266			(unsigned long)kmap_atomic(sg_page((&bounce_sgl[j])),
267						KM_IRQ0);
268
269		while (srclen) {
270			/* assume bounce offset always == 0 */
271			dest = bounce_addr + bounce_sgl[j].length;
272			destlen = PAGE_SIZE - bounce_sgl[j].length;
273
274			copylen = min(srclen, destlen);
275			memcpy((void *)dest, (void *)src, copylen);
276
277			total_copied += copylen;
278			bounce_sgl[j].length += copylen;
279			srclen -= copylen;
280			src += copylen;
281
282			if (bounce_sgl[j].length == PAGE_SIZE) {
283				/* full..move to next entry */
284				kunmap_atomic((void *)bounce_addr, KM_IRQ0);
285				j++;
286
287				/* if we need to use another bounce buffer */
288				if (srclen || i != orig_sgl_count - 1)
289					bounce_addr =
290					(unsigned long)kmap_atomic(
291					sg_page((&bounce_sgl[j])), KM_IRQ0);
292
293			} else if (srclen == 0 && i == orig_sgl_count - 1) {
294				/* unmap the last bounce that is < PAGE_SIZE */
295				kunmap_atomic((void *)bounce_addr, KM_IRQ0);
296			}
297		}
298
299		kunmap_atomic((void *)(src_addr - orig_sgl[i].offset), KM_IRQ0);
300	}
301
302	local_irq_restore(flags);
303
304	return total_copied;
305}
306
307
308static int storvsc_remove(struct hv_device *dev)
309{
310	struct Scsi_Host *host = dev_get_drvdata(&dev->device);
311	struct hv_host_device *host_dev =
312			(struct hv_host_device *)host->hostdata;
313
314	scsi_remove_host(host);
315
316	scsi_host_put(host);
317
318	storvsc_dev_remove(dev);
319	if (host_dev->request_pool) {
320		kmem_cache_destroy(host_dev->request_pool);
321		host_dev->request_pool = NULL;
322	}
323	return 0;
324}
325
326
327static int storvsc_get_chs(struct scsi_device *sdev, struct block_device * bdev,
328			   sector_t capacity, int *info)
329{
330	sector_t nsect = capacity;
331	sector_t cylinders = nsect;
332	int heads, sectors_pt;
333
334	/*
335	 * We are making up these values; let us keep it simple.
336	 */
337	heads = 0xff;
338	sectors_pt = 0x3f;      /* Sectors per track */
339	sector_div(cylinders, heads * sectors_pt);
340	if ((sector_t)(cylinders + 1) * heads * sectors_pt < nsect)
341		cylinders = 0xffff;
342
343	info[0] = heads;
344	info[1] = sectors_pt;
345	info[2] = (int)cylinders;
346
347	return 0;
348}
349
350static int storvsc_host_reset(struct hv_device *device)
351{
352	struct storvsc_device *stor_device;
353	struct hv_storvsc_request *request;
354	struct vstor_packet *vstor_packet;
355	int ret, t;
356
357
358	stor_device = get_stor_device(device);
359	if (!stor_device)
360		return -1;
361
362	request = &stor_device->reset_request;
363	vstor_packet = &request->vstor_packet;
364
365	init_completion(&request->wait_event);
366
367	vstor_packet->operation = VSTOR_OPERATION_RESET_BUS;
368	vstor_packet->flags = REQUEST_COMPLETION_FLAG;
369	vstor_packet->vm_srb.path_id = stor_device->path_id;
370
371	ret = vmbus_sendpacket(device->channel, vstor_packet,
372			       sizeof(struct vstor_packet),
373			       (unsigned long)&stor_device->reset_request,
374			       VM_PKT_DATA_INBAND,
375			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
376	if (ret != 0)
377		goto cleanup;
378
379	t = wait_for_completion_timeout(&request->wait_event, 5*HZ);
380	if (t == 0) {
381		ret = -ETIMEDOUT;
382		goto cleanup;
383	}
384
385
386	/*
387	 * At this point, all outstanding requests in the adapter
388	 * should have been flushed out and return to us
389	 */
390
391cleanup:
392	put_stor_device(device);
393	return ret;
394}
395
396
397/*
398 * storvsc_host_reset_handler - Reset the scsi HBA
399 */
400static int storvsc_host_reset_handler(struct scsi_cmnd *scmnd)
401{
402	int ret;
403	struct hv_host_device *host_dev =
404		(struct hv_host_device *)scmnd->device->host->hostdata;
405	struct hv_device *dev = host_dev->dev;
406
407	ret = storvsc_host_reset(dev);
408	if (ret != 0)
409		return ret;
410
411	return ret;
412}
413
414
415/*
416 * storvsc_commmand_completion - Command completion processing
417 */
418static void storvsc_commmand_completion(struct hv_storvsc_request *request)
419{
420	struct storvsc_cmd_request *cmd_request =
421		(struct storvsc_cmd_request *)request->context;
422	struct scsi_cmnd *scmnd = cmd_request->cmd;
423	struct hv_host_device *host_dev =
424		(struct hv_host_device *)scmnd->device->host->hostdata;
425	void (*scsi_done_fn)(struct scsi_cmnd *);
426	struct scsi_sense_hdr sense_hdr;
427	struct vmscsi_request *vm_srb;
428
429	if (cmd_request->bounce_sgl_count) {
430
431		/* FIXME: We can optimize on writes by just skipping this */
432		copy_from_bounce_buffer(scsi_sglist(scmnd),
433					cmd_request->bounce_sgl,
434					scsi_sg_count(scmnd));
435		destroy_bounce_buffer(cmd_request->bounce_sgl,
436				      cmd_request->bounce_sgl_count);
437	}
438
439	vm_srb = &request->vstor_packet.vm_srb;
440	scmnd->result = vm_srb->scsi_status;
441
442	if (scmnd->result) {
443		if (scsi_normalize_sense(scmnd->sense_buffer,
444				SCSI_SENSE_BUFFERSIZE, &sense_hdr))
445			scsi_print_sense_hdr("storvsc", &sense_hdr);
446	}
447
448	scsi_set_resid(scmnd,
449		request->data_buffer.len -
450		vm_srb->data_transfer_length);
451
452	scsi_done_fn = scmnd->scsi_done;
453
454	scmnd->host_scribble = NULL;
455	scmnd->scsi_done = NULL;
456
457	scsi_done_fn(scmnd);
458
459	kmem_cache_free(host_dev->request_pool, cmd_request);
460}
461
462
463/*
464 * storvsc_queuecommand - Initiate command processing
465 */
466static int storvsc_queuecommand_lck(struct scsi_cmnd *scmnd,
467				void (*done)(struct scsi_cmnd *))
468{
469	int ret;
470	struct hv_host_device *host_dev =
471		(struct hv_host_device *)scmnd->device->host->hostdata;
472	struct hv_device *dev = host_dev->dev;
473	struct hv_storvsc_request *request;
474	struct storvsc_cmd_request *cmd_request;
475	unsigned int request_size = 0;
476	int i;
477	struct scatterlist *sgl;
478	unsigned int sg_count = 0;
479	struct vmscsi_request *vm_srb;
480
481
482	/* If retrying, no need to prep the cmd */
483	if (scmnd->host_scribble) {
484
485		cmd_request =
486			(struct storvsc_cmd_request *)scmnd->host_scribble;
487
488		goto retry_request;
489	}
490
491	scmnd->scsi_done = done;
492
493	request_size = sizeof(struct storvsc_cmd_request);
494
495	cmd_request = kmem_cache_zalloc(host_dev->request_pool,
496				       GFP_ATOMIC);
497	if (!cmd_request) {
498		scmnd->scsi_done = NULL;
499		return SCSI_MLQUEUE_DEVICE_BUSY;
500	}
501
502	/* Setup the cmd request */
503	cmd_request->bounce_sgl_count = 0;
504	cmd_request->bounce_sgl = NULL;
505	cmd_request->cmd = scmnd;
506
507	scmnd->host_scribble = (unsigned char *)cmd_request;
508
509	request = &cmd_request->request;
510	vm_srb = &request->vstor_packet.vm_srb;
511
512
513	/* Build the SRB */
514	switch (scmnd->sc_data_direction) {
515	case DMA_TO_DEVICE:
516		vm_srb->data_in = WRITE_TYPE;
517		break;
518	case DMA_FROM_DEVICE:
519		vm_srb->data_in = READ_TYPE;
520		break;
521	default:
522		vm_srb->data_in = UNKNOWN_TYPE;
523		break;
524	}
525
526	request->on_io_completion = storvsc_commmand_completion;
527	request->context = cmd_request;/* scmnd; */
528
529	vm_srb->port_number = host_dev->port;
530	vm_srb->path_id = scmnd->device->channel;
531	vm_srb->target_id = scmnd->device->id;
532	vm_srb->lun = scmnd->device->lun;
533
534	vm_srb->cdb_length = scmnd->cmd_len;
535
536	memcpy(vm_srb->cdb, scmnd->cmnd, vm_srb->cdb_length);
537
538	request->sense_buffer = scmnd->sense_buffer;
539
540
541	request->data_buffer.len = scsi_bufflen(scmnd);
542	if (scsi_sg_count(scmnd)) {
543		sgl = (struct scatterlist *)scsi_sglist(scmnd);
544		sg_count = scsi_sg_count(scmnd);
545
546		/* check if we need to bounce the sgl */
547		if (do_bounce_buffer(sgl, scsi_sg_count(scmnd)) != -1) {
548			cmd_request->bounce_sgl =
549				create_bounce_buffer(sgl, scsi_sg_count(scmnd),
550						     scsi_bufflen(scmnd));
551			if (!cmd_request->bounce_sgl) {
552				scmnd->scsi_done = NULL;
553				scmnd->host_scribble = NULL;
554				kmem_cache_free(host_dev->request_pool,
555						cmd_request);
556
557				return SCSI_MLQUEUE_HOST_BUSY;
558			}
559
560			cmd_request->bounce_sgl_count =
561				ALIGN(scsi_bufflen(scmnd), PAGE_SIZE) >>
562					PAGE_SHIFT;
563
564			/*
565			 * FIXME: We can optimize on reads by just skipping
566			 * this
567			 */
568			copy_to_bounce_buffer(sgl, cmd_request->bounce_sgl,
569					      scsi_sg_count(scmnd));
570
571			sgl = cmd_request->bounce_sgl;
572			sg_count = cmd_request->bounce_sgl_count;
573		}
574
575		request->data_buffer.offset = sgl[0].offset;
576
577		for (i = 0; i < sg_count; i++)
578			request->data_buffer.pfn_array[i] =
579				page_to_pfn(sg_page((&sgl[i])));
580
581	} else if (scsi_sglist(scmnd)) {
582		request->data_buffer.offset =
583			virt_to_phys(scsi_sglist(scmnd)) & (PAGE_SIZE-1);
584		request->data_buffer.pfn_array[0] =
585			virt_to_phys(scsi_sglist(scmnd)) >> PAGE_SHIFT;
586	}
587
588retry_request:
589	/* Invokes the vsc to start an IO */
590	ret = storvsc_do_io(dev, &cmd_request->request);
591
592	if (ret == -1) {
593		/* no more space */
594
595		if (cmd_request->bounce_sgl_count) {
596			/*
597			 * FIXME: We can optimize on writes by just skipping
598			 * this
599			 */
600			copy_from_bounce_buffer(scsi_sglist(scmnd),
601						cmd_request->bounce_sgl,
602						scsi_sg_count(scmnd));
603			destroy_bounce_buffer(cmd_request->bounce_sgl,
604					      cmd_request->bounce_sgl_count);
605		}
606
607		kmem_cache_free(host_dev->request_pool, cmd_request);
608
609		scmnd->scsi_done = NULL;
610		scmnd->host_scribble = NULL;
611
612		ret = SCSI_MLQUEUE_DEVICE_BUSY;
613	}
614
615	return ret;
616}
617
618static DEF_SCSI_QCMD(storvsc_queuecommand)
619
620
621/* Scsi driver */
622static struct scsi_host_template scsi_driver = {
623	.module	=		THIS_MODULE,
624	.name =			"storvsc_host_t",
625	.bios_param =		storvsc_get_chs,
626	.queuecommand =		storvsc_queuecommand,
627	.eh_host_reset_handler =	storvsc_host_reset_handler,
628	.slave_alloc =		storvsc_device_alloc,
629	.slave_configure =	storvsc_device_configure,
630	.cmd_per_lun =		1,
631	/* 64 max_queue * 1 target */
632	.can_queue =		STORVSC_MAX_IO_REQUESTS*STORVSC_MAX_TARGETS,
633	.this_id =		-1,
634	/* no use setting to 0 since ll_blk_rw reset it to 1 */
635	/* currently 32 */
636	.sg_tablesize =		MAX_MULTIPAGE_BUFFER_COUNT,
637	/*
638	 * ENABLE_CLUSTERING allows mutiple physically contig bio_vecs to merge
639	 * into 1 sg element. If set, we must limit the max_segment_size to
640	 * PAGE_SIZE, otherwise we may get 1 sg element that represents
641	 * multiple
642	 */
643	/* physically contig pfns (ie sg[x].length > PAGE_SIZE). */
644	.use_clustering =	ENABLE_CLUSTERING,
645	/* Make sure we dont get a sg segment crosses a page boundary */
646	.dma_boundary =		PAGE_SIZE-1,
647};
648
649
650/*
651 * storvsc_probe - Add a new device for this driver
652 */
653
654static int storvsc_probe(struct hv_device *device)
655{
656	int ret;
657	struct Scsi_Host *host;
658	struct hv_host_device *host_dev;
659	struct storvsc_device_info device_info;
660
661	host = scsi_host_alloc(&scsi_driver,
662			       sizeof(struct hv_host_device));
663	if (!host)
664		return -ENOMEM;
665
666	dev_set_drvdata(&device->device, host);
667
668	host_dev = (struct hv_host_device *)host->hostdata;
669	memset(host_dev, 0, sizeof(struct hv_host_device));
670
671	host_dev->port = host->host_no;
672	host_dev->dev = device;
673
674	host_dev->request_pool =
675				kmem_cache_create(dev_name(&device->device),
676					sizeof(struct storvsc_cmd_request), 0,
677					SLAB_HWCACHE_ALIGN, NULL);
678
679	if (!host_dev->request_pool) {
680		scsi_host_put(host);
681		return -ENOMEM;
682	}
683
684	device_info.port_number = host->host_no;
685	device_info.ring_buffer_size  = storvsc_ringbuffer_size;
686	/* Call to the vsc driver to add the device */
687	ret = storvsc_dev_add(device, (void *)&device_info);
688
689	if (ret != 0) {
690		kmem_cache_destroy(host_dev->request_pool);
691		scsi_host_put(host);
692		return -1;
693	}
694
695	host_dev->path = device_info.path_id;
696	host_dev->target = device_info.target_id;
697
698	/* max # of devices per target */
699	host->max_lun = STORVSC_MAX_LUNS_PER_TARGET;
700	/* max # of targets per channel */
701	host->max_id = STORVSC_MAX_TARGETS;
702	/* max # of channels */
703	host->max_channel = STORVSC_MAX_CHANNELS - 1;
704	/* max cmd length */
705	host->max_cmd_len = STORVSC_MAX_CMD_LEN;
706
707	/* Register the HBA and start the scsi bus scan */
708	ret = scsi_add_host(host, &device->device);
709	if (ret != 0) {
710
711		storvsc_dev_remove(device);
712
713		kmem_cache_destroy(host_dev->request_pool);
714		scsi_host_put(host);
715		return -1;
716	}
717
718	scsi_scan_host(host);
719	return ret;
720}
721
722/* The one and only one */
723
724static struct hv_driver storvsc_drv = {
725	.probe = storvsc_probe,
726	.remove = storvsc_remove,
727};
728
729/*
730 * We use a DMI table to determine if we should autoload this driver  This is
731 * needed by distro tools to determine if the hyperv drivers should be
732 * installed and/or configured.  We don't do anything else with the table, but
733 * it needs to be present.
734 */
735
736static const struct dmi_system_id __initconst
737hv_stor_dmi_table[] __maybe_unused  = {
738	{
739		.ident = "Hyper-V",
740		.matches = {
741			DMI_MATCH(DMI_SYS_VENDOR, "Microsoft Corporation"),
742			DMI_MATCH(DMI_PRODUCT_NAME, "Virtual Machine"),
743			DMI_MATCH(DMI_BOARD_NAME, "Virtual Machine"),
744		},
745	},
746	{ },
747};
748MODULE_DEVICE_TABLE(dmi, hv_stor_dmi_table);
749
750static int __init storvsc_drv_init(void)
751{
752	int ret;
753	struct hv_driver *drv = &storvsc_drv;
754	u32 max_outstanding_req_per_channel;
755
756	/*
757	 * Divide the ring buffer data size (which is 1 page less
758	 * than the ring buffer size since that page is reserved for
759	 * the ring buffer indices) by the max request size (which is
760	 * vmbus_channel_packet_multipage_buffer + struct vstor_packet + u64)
761	 */
762
763	max_outstanding_req_per_channel =
764	((storvsc_ringbuffer_size - PAGE_SIZE) /
765	ALIGN(MAX_MULTIPAGE_BUFFER_PACKET +
766	sizeof(struct vstor_packet) + sizeof(u64),
767	sizeof(u64)));
768
769	memcpy(&drv->dev_type, &stor_vsci_device_type,
770	       sizeof(struct hv_guid));
771
772	if (max_outstanding_req_per_channel <
773	    STORVSC_MAX_IO_REQUESTS)
774		return -1;
775
776	drv->driver.name = driver_name;
777
778
779	/* The driver belongs to vmbus */
780	ret = vmbus_child_driver_register(&drv->driver);
781
782	return ret;
783}
784
785static void __exit storvsc_drv_exit(void)
786{
787	vmbus_child_driver_unregister(&storvsc_drv.driver);
788}
789
790MODULE_LICENSE("GPL");
791MODULE_VERSION(HV_DRV_VERSION);
792MODULE_DESCRIPTION("Microsoft Hyper-V virtual storage driver");
793module_init(storvsc_drv_init);
794module_exit(storvsc_drv_exit);