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38#include <linux/interrupt.h>
39#include <linux/blkdev.h>
40#include <linux/hdreg.h>
41#include <linux/cdrom.h>
42#include <linux/module.h>
43#include <linux/slab.h>
44#include <linux/mutex.h>
45#include <linux/scatterlist.h>
46
47#include <xen/xen.h>
48#include <xen/xenbus.h>
49#include <xen/grant_table.h>
50#include <xen/events.h>
51#include <xen/page.h>
52#include <xen/platform_pci.h>
53
54#include <xen/interface/grant_table.h>
55#include <xen/interface/io/blkif.h>
56#include <xen/interface/io/protocols.h>
57
58#include <asm/xen/hypervisor.h>
59
60enum blkif_state {
61 BLKIF_STATE_DISCONNECTED,
62 BLKIF_STATE_CONNECTED,
63 BLKIF_STATE_SUSPENDED,
64};
65
66struct blk_shadow {
67 struct blkif_request req;
68 struct request *request;
69 unsigned long frame[BLKIF_MAX_SEGMENTS_PER_REQUEST];
70};
71
72static DEFINE_MUTEX(blkfront_mutex);
73static const struct block_device_operations xlvbd_block_fops;
74
75#define BLK_RING_SIZE __CONST_RING_SIZE(blkif, PAGE_SIZE)
76
77
78
79
80
81
82struct blkfront_info
83{
84 struct mutex mutex;
85 struct xenbus_device *xbdev;
86 struct gendisk *gd;
87 int vdevice;
88 blkif_vdev_t handle;
89 enum blkif_state connected;
90 int ring_ref;
91 struct blkif_front_ring ring;
92 struct scatterlist sg[BLKIF_MAX_SEGMENTS_PER_REQUEST];
93 unsigned int evtchn, irq;
94 struct request_queue *rq;
95 struct work_struct work;
96 struct gnttab_free_callback callback;
97 struct blk_shadow shadow[BLK_RING_SIZE];
98 unsigned long shadow_free;
99 unsigned int feature_flush;
100 int is_ready;
101};
102
103static DEFINE_SPINLOCK(blkif_io_lock);
104
105static unsigned int nr_minors;
106static unsigned long *minors;
107static DEFINE_SPINLOCK(minor_lock);
108
109#define MAXIMUM_OUTSTANDING_BLOCK_REQS \
110 (BLKIF_MAX_SEGMENTS_PER_REQUEST * BLK_RING_SIZE)
111#define GRANT_INVALID_REF 0
112
113#define PARTS_PER_DISK 16
114#define PARTS_PER_EXT_DISK 256
115
116#define BLKIF_MAJOR(dev) ((dev)>>8)
117#define BLKIF_MINOR(dev) ((dev) & 0xff)
118
119#define EXT_SHIFT 28
120#define EXTENDED (1<<EXT_SHIFT)
121#define VDEV_IS_EXTENDED(dev) ((dev)&(EXTENDED))
122#define BLKIF_MINOR_EXT(dev) ((dev)&(~EXTENDED))
123
124#define DEV_NAME "xvd"
125
126static int get_id_from_freelist(struct blkfront_info *info)
127{
128 unsigned long free = info->shadow_free;
129 BUG_ON(free >= BLK_RING_SIZE);
130 info->shadow_free = info->shadow[free].req.id;
131 info->shadow[free].req.id = 0x0fffffee;
132 return free;
133}
134
135static void add_id_to_freelist(struct blkfront_info *info,
136 unsigned long id)
137{
138 info->shadow[id].req.id = info->shadow_free;
139 info->shadow[id].request = NULL;
140 info->shadow_free = id;
141}
142
143static int xlbd_reserve_minors(unsigned int minor, unsigned int nr)
144{
145 unsigned int end = minor + nr;
146 int rc;
147
148 if (end > nr_minors) {
149 unsigned long *bitmap, *old;
150
151 bitmap = kzalloc(BITS_TO_LONGS(end) * sizeof(*bitmap),
152 GFP_KERNEL);
153 if (bitmap == NULL)
154 return -ENOMEM;
155
156 spin_lock(&minor_lock);
157 if (end > nr_minors) {
158 old = minors;
159 memcpy(bitmap, minors,
160 BITS_TO_LONGS(nr_minors) * sizeof(*bitmap));
161 minors = bitmap;
162 nr_minors = BITS_TO_LONGS(end) * BITS_PER_LONG;
163 } else
164 old = bitmap;
165 spin_unlock(&minor_lock);
166 kfree(old);
167 }
168
169 spin_lock(&minor_lock);
170 if (find_next_bit(minors, end, minor) >= end) {
171 for (; minor < end; ++minor)
172 __set_bit(minor, minors);
173 rc = 0;
174 } else
175 rc = -EBUSY;
176 spin_unlock(&minor_lock);
177
178 return rc;
179}
180
181static void xlbd_release_minors(unsigned int minor, unsigned int nr)
182{
183 unsigned int end = minor + nr;
184
185 BUG_ON(end > nr_minors);
186 spin_lock(&minor_lock);
187 for (; minor < end; ++minor)
188 __clear_bit(minor, minors);
189 spin_unlock(&minor_lock);
190}
191
192static void blkif_restart_queue_callback(void *arg)
193{
194 struct blkfront_info *info = (struct blkfront_info *)arg;
195 schedule_work(&info->work);
196}
197
198static int blkif_getgeo(struct block_device *bd, struct hd_geometry *hg)
199{
200
201
202 sector_t nsect = get_capacity(bd->bd_disk);
203 sector_t cylinders = nsect;
204
205 hg->heads = 0xff;
206 hg->sectors = 0x3f;
207 sector_div(cylinders, hg->heads * hg->sectors);
208 hg->cylinders = cylinders;
209 if ((sector_t)(hg->cylinders + 1) * hg->heads * hg->sectors < nsect)
210 hg->cylinders = 0xffff;
211 return 0;
212}
213
214static int blkif_ioctl(struct block_device *bdev, fmode_t mode,
215 unsigned command, unsigned long argument)
216{
217 struct blkfront_info *info = bdev->bd_disk->private_data;
218 int i;
219
220 dev_dbg(&info->xbdev->dev, "command: 0x%x, argument: 0x%lx\n",
221 command, (long)argument);
222
223 switch (command) {
224 case CDROMMULTISESSION:
225 dev_dbg(&info->xbdev->dev, "FIXME: support multisession CDs later\n");
226 for (i = 0; i < sizeof(struct cdrom_multisession); i++)
227 if (put_user(0, (char __user *)(argument + i)))
228 return -EFAULT;
229 return 0;
230
231 case CDROM_GET_CAPABILITY: {
232 struct gendisk *gd = info->gd;
233 if (gd->flags & GENHD_FL_CD)
234 return 0;
235 return -EINVAL;
236 }
237
238 default:
239
240
241 return -EINVAL;
242 }
243
244 return 0;
245}
246
247
248
249
250
251
252
253
254static int blkif_queue_request(struct request *req)
255{
256 struct blkfront_info *info = req->rq_disk->private_data;
257 unsigned long buffer_mfn;
258 struct blkif_request *ring_req;
259 unsigned long id;
260 unsigned int fsect, lsect;
261 int i, ref;
262 grant_ref_t gref_head;
263 struct scatterlist *sg;
264
265 if (unlikely(info->connected != BLKIF_STATE_CONNECTED))
266 return 1;
267
268 if (gnttab_alloc_grant_references(
269 BLKIF_MAX_SEGMENTS_PER_REQUEST, &gref_head) < 0) {
270 gnttab_request_free_callback(
271 &info->callback,
272 blkif_restart_queue_callback,
273 info,
274 BLKIF_MAX_SEGMENTS_PER_REQUEST);
275 return 1;
276 }
277
278
279 ring_req = RING_GET_REQUEST(&info->ring, info->ring.req_prod_pvt);
280 id = get_id_from_freelist(info);
281 info->shadow[id].request = req;
282
283 ring_req->id = id;
284 ring_req->sector_number = (blkif_sector_t)blk_rq_pos(req);
285 ring_req->handle = info->handle;
286
287 ring_req->operation = rq_data_dir(req) ?
288 BLKIF_OP_WRITE : BLKIF_OP_READ;
289
290 if (req->cmd_flags & (REQ_FLUSH | REQ_FUA)) {
291
292
293
294
295
296
297
298
299 ring_req->operation = BLKIF_OP_WRITE_BARRIER;
300 }
301
302 ring_req->nr_segments = blk_rq_map_sg(req->q, req, info->sg);
303 BUG_ON(ring_req->nr_segments > BLKIF_MAX_SEGMENTS_PER_REQUEST);
304
305 for_each_sg(info->sg, sg, ring_req->nr_segments, i) {
306 buffer_mfn = pfn_to_mfn(page_to_pfn(sg_page(sg)));
307 fsect = sg->offset >> 9;
308 lsect = fsect + (sg->length >> 9) - 1;
309
310 ref = gnttab_claim_grant_reference(&gref_head);
311 BUG_ON(ref == -ENOSPC);
312
313 gnttab_grant_foreign_access_ref(
314 ref,
315 info->xbdev->otherend_id,
316 buffer_mfn,
317 rq_data_dir(req) );
318
319 info->shadow[id].frame[i] = mfn_to_pfn(buffer_mfn);
320 ring_req->seg[i] =
321 (struct blkif_request_segment) {
322 .gref = ref,
323 .first_sect = fsect,
324 .last_sect = lsect };
325 }
326
327 info->ring.req_prod_pvt++;
328
329
330 info->shadow[id].req = *ring_req;
331
332 gnttab_free_grant_references(gref_head);
333
334 return 0;
335}
336
337
338static inline void flush_requests(struct blkfront_info *info)
339{
340 int notify;
341
342 RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&info->ring, notify);
343
344 if (notify)
345 notify_remote_via_irq(info->irq);
346}
347
348
349
350
351
352static void do_blkif_request(struct request_queue *rq)
353{
354 struct blkfront_info *info = NULL;
355 struct request *req;
356 int queued;
357
358 pr_debug("Entered do_blkif_request\n");
359
360 queued = 0;
361
362 while ((req = blk_peek_request(rq)) != NULL) {
363 info = req->rq_disk->private_data;
364
365 if (RING_FULL(&info->ring))
366 goto wait;
367
368 blk_start_request(req);
369
370 if (req->cmd_type != REQ_TYPE_FS) {
371 __blk_end_request_all(req, -EIO);
372 continue;
373 }
374
375 pr_debug("do_blk_req %p: cmd %p, sec %lx, "
376 "(%u/%u) buffer:%p [%s]\n",
377 req, req->cmd, (unsigned long)blk_rq_pos(req),
378 blk_rq_cur_sectors(req), blk_rq_sectors(req),
379 req->buffer, rq_data_dir(req) ? "write" : "read");
380
381 if (blkif_queue_request(req)) {
382 blk_requeue_request(rq, req);
383wait:
384
385 blk_stop_queue(rq);
386 break;
387 }
388
389 queued++;
390 }
391
392 if (queued != 0)
393 flush_requests(info);
394}
395
396static int xlvbd_init_blk_queue(struct gendisk *gd, u16 sector_size)
397{
398 struct request_queue *rq;
399
400 rq = blk_init_queue(do_blkif_request, &blkif_io_lock);
401 if (rq == NULL)
402 return -1;
403
404 queue_flag_set_unlocked(QUEUE_FLAG_VIRT, rq);
405
406
407 blk_queue_logical_block_size(rq, sector_size);
408 blk_queue_max_hw_sectors(rq, 512);
409
410
411 blk_queue_segment_boundary(rq, PAGE_SIZE - 1);
412 blk_queue_max_segment_size(rq, PAGE_SIZE);
413
414
415 blk_queue_max_segments(rq, BLKIF_MAX_SEGMENTS_PER_REQUEST);
416
417
418 blk_queue_dma_alignment(rq, 511);
419
420
421 blk_queue_bounce_limit(rq, BLK_BOUNCE_ANY);
422
423 gd->queue = rq;
424
425 return 0;
426}
427
428
429static void xlvbd_flush(struct blkfront_info *info)
430{
431 blk_queue_flush(info->rq, info->feature_flush);
432 printk(KERN_INFO "blkfront: %s: barriers %s\n",
433 info->gd->disk_name,
434 info->feature_flush ? "enabled" : "disabled");
435}
436
437
438static int xlvbd_alloc_gendisk(blkif_sector_t capacity,
439 struct blkfront_info *info,
440 u16 vdisk_info, u16 sector_size)
441{
442 struct gendisk *gd;
443 int nr_minors = 1;
444 int err = -ENODEV;
445 unsigned int offset;
446 int minor;
447 int nr_parts;
448
449 BUG_ON(info->gd != NULL);
450 BUG_ON(info->rq != NULL);
451
452 if ((info->vdevice>>EXT_SHIFT) > 1) {
453
454 printk(KERN_WARNING "blkfront: vdevice 0x%x is above the extended range; ignoring\n", info->vdevice);
455 return -ENODEV;
456 }
457
458 if (!VDEV_IS_EXTENDED(info->vdevice)) {
459 minor = BLKIF_MINOR(info->vdevice);
460 nr_parts = PARTS_PER_DISK;
461 } else {
462 minor = BLKIF_MINOR_EXT(info->vdevice);
463 nr_parts = PARTS_PER_EXT_DISK;
464 }
465
466 if ((minor % nr_parts) == 0)
467 nr_minors = nr_parts;
468
469 err = xlbd_reserve_minors(minor, nr_minors);
470 if (err)
471 goto out;
472 err = -ENODEV;
473
474 gd = alloc_disk(nr_minors);
475 if (gd == NULL)
476 goto release;
477
478 offset = minor / nr_parts;
479
480 if (nr_minors > 1) {
481 if (offset < 26)
482 sprintf(gd->disk_name, "%s%c", DEV_NAME, 'a' + offset);
483 else
484 sprintf(gd->disk_name, "%s%c%c", DEV_NAME,
485 'a' + ((offset / 26)-1), 'a' + (offset % 26));
486 } else {
487 if (offset < 26)
488 sprintf(gd->disk_name, "%s%c%d", DEV_NAME,
489 'a' + offset,
490 minor & (nr_parts - 1));
491 else
492 sprintf(gd->disk_name, "%s%c%c%d", DEV_NAME,
493 'a' + ((offset / 26) - 1),
494 'a' + (offset % 26),
495 minor & (nr_parts - 1));
496 }
497
498 gd->major = XENVBD_MAJOR;
499 gd->first_minor = minor;
500 gd->fops = &xlvbd_block_fops;
501 gd->private_data = info;
502 gd->driverfs_dev = &(info->xbdev->dev);
503 set_capacity(gd, capacity);
504
505 if (xlvbd_init_blk_queue(gd, sector_size)) {
506 del_gendisk(gd);
507 goto release;
508 }
509
510 info->rq = gd->queue;
511 info->gd = gd;
512
513 xlvbd_flush(info);
514
515 if (vdisk_info & VDISK_READONLY)
516 set_disk_ro(gd, 1);
517
518 if (vdisk_info & VDISK_REMOVABLE)
519 gd->flags |= GENHD_FL_REMOVABLE;
520
521 if (vdisk_info & VDISK_CDROM)
522 gd->flags |= GENHD_FL_CD;
523
524 return 0;
525
526 release:
527 xlbd_release_minors(minor, nr_minors);
528 out:
529 return err;
530}
531
532static void xlvbd_release_gendisk(struct blkfront_info *info)
533{
534 unsigned int minor, nr_minors;
535 unsigned long flags;
536
537 if (info->rq == NULL)
538 return;
539
540 spin_lock_irqsave(&blkif_io_lock, flags);
541
542
543 blk_stop_queue(info->rq);
544
545
546 gnttab_cancel_free_callback(&info->callback);
547 spin_unlock_irqrestore(&blkif_io_lock, flags);
548
549
550 flush_work_sync(&info->work);
551
552 del_gendisk(info->gd);
553
554 minor = info->gd->first_minor;
555 nr_minors = info->gd->minors;
556 xlbd_release_minors(minor, nr_minors);
557
558 blk_cleanup_queue(info->rq);
559 info->rq = NULL;
560
561 put_disk(info->gd);
562 info->gd = NULL;
563}
564
565static void kick_pending_request_queues(struct blkfront_info *info)
566{
567 if (!RING_FULL(&info->ring)) {
568
569 blk_start_queue(info->rq);
570
571 do_blkif_request(info->rq);
572 }
573}
574
575static void blkif_restart_queue(struct work_struct *work)
576{
577 struct blkfront_info *info = container_of(work, struct blkfront_info, work);
578
579 spin_lock_irq(&blkif_io_lock);
580 if (info->connected == BLKIF_STATE_CONNECTED)
581 kick_pending_request_queues(info);
582 spin_unlock_irq(&blkif_io_lock);
583}
584
585static void blkif_free(struct blkfront_info *info, int suspend)
586{
587
588 spin_lock_irq(&blkif_io_lock);
589 info->connected = suspend ?
590 BLKIF_STATE_SUSPENDED : BLKIF_STATE_DISCONNECTED;
591
592 if (info->rq)
593 blk_stop_queue(info->rq);
594
595 gnttab_cancel_free_callback(&info->callback);
596 spin_unlock_irq(&blkif_io_lock);
597
598
599 flush_work_sync(&info->work);
600
601
602 if (info->ring_ref != GRANT_INVALID_REF) {
603 gnttab_end_foreign_access(info->ring_ref, 0,
604 (unsigned long)info->ring.sring);
605 info->ring_ref = GRANT_INVALID_REF;
606 info->ring.sring = NULL;
607 }
608 if (info->irq)
609 unbind_from_irqhandler(info->irq, info);
610 info->evtchn = info->irq = 0;
611
612}
613
614static void blkif_completion(struct blk_shadow *s)
615{
616 int i;
617 for (i = 0; i < s->req.nr_segments; i++)
618 gnttab_end_foreign_access(s->req.seg[i].gref, 0, 0UL);
619}
620
621static irqreturn_t blkif_interrupt(int irq, void *dev_id)
622{
623 struct request *req;
624 struct blkif_response *bret;
625 RING_IDX i, rp;
626 unsigned long flags;
627 struct blkfront_info *info = (struct blkfront_info *)dev_id;
628 int error;
629
630 spin_lock_irqsave(&blkif_io_lock, flags);
631
632 if (unlikely(info->connected != BLKIF_STATE_CONNECTED)) {
633 spin_unlock_irqrestore(&blkif_io_lock, flags);
634 return IRQ_HANDLED;
635 }
636
637 again:
638 rp = info->ring.sring->rsp_prod;
639 rmb();
640
641 for (i = info->ring.rsp_cons; i != rp; i++) {
642 unsigned long id;
643
644 bret = RING_GET_RESPONSE(&info->ring, i);
645 id = bret->id;
646 req = info->shadow[id].request;
647
648 blkif_completion(&info->shadow[id]);
649
650 add_id_to_freelist(info, id);
651
652 error = (bret->status == BLKIF_RSP_OKAY) ? 0 : -EIO;
653 switch (bret->operation) {
654 case BLKIF_OP_WRITE_BARRIER:
655 if (unlikely(bret->status == BLKIF_RSP_EOPNOTSUPP)) {
656 printk(KERN_WARNING "blkfront: %s: write barrier op failed\n",
657 info->gd->disk_name);
658 error = -EOPNOTSUPP;
659 }
660 if (unlikely(bret->status == BLKIF_RSP_ERROR &&
661 info->shadow[id].req.nr_segments == 0)) {
662 printk(KERN_WARNING "blkfront: %s: empty write barrier op failed\n",
663 info->gd->disk_name);
664 error = -EOPNOTSUPP;
665 }
666 if (unlikely(error)) {
667 if (error == -EOPNOTSUPP)
668 error = 0;
669 info->feature_flush = 0;
670 xlvbd_flush(info);
671 }
672
673 case BLKIF_OP_READ:
674 case BLKIF_OP_WRITE:
675 if (unlikely(bret->status != BLKIF_RSP_OKAY))
676 dev_dbg(&info->xbdev->dev, "Bad return from blkdev data "
677 "request: %x\n", bret->status);
678
679 __blk_end_request_all(req, error);
680 break;
681 default:
682 BUG();
683 }
684 }
685
686 info->ring.rsp_cons = i;
687
688 if (i != info->ring.req_prod_pvt) {
689 int more_to_do;
690 RING_FINAL_CHECK_FOR_RESPONSES(&info->ring, more_to_do);
691 if (more_to_do)
692 goto again;
693 } else
694 info->ring.sring->rsp_event = i + 1;
695
696 kick_pending_request_queues(info);
697
698 spin_unlock_irqrestore(&blkif_io_lock, flags);
699
700 return IRQ_HANDLED;
701}
702
703
704static int setup_blkring(struct xenbus_device *dev,
705 struct blkfront_info *info)
706{
707 struct blkif_sring *sring;
708 int err;
709
710 info->ring_ref = GRANT_INVALID_REF;
711
712 sring = (struct blkif_sring *)__get_free_page(GFP_NOIO | __GFP_HIGH);
713 if (!sring) {
714 xenbus_dev_fatal(dev, -ENOMEM, "allocating shared ring");
715 return -ENOMEM;
716 }
717 SHARED_RING_INIT(sring);
718 FRONT_RING_INIT(&info->ring, sring, PAGE_SIZE);
719
720 sg_init_table(info->sg, BLKIF_MAX_SEGMENTS_PER_REQUEST);
721
722 err = xenbus_grant_ring(dev, virt_to_mfn(info->ring.sring));
723 if (err < 0) {
724 free_page((unsigned long)sring);
725 info->ring.sring = NULL;
726 goto fail;
727 }
728 info->ring_ref = err;
729
730 err = xenbus_alloc_evtchn(dev, &info->evtchn);
731 if (err)
732 goto fail;
733
734 err = bind_evtchn_to_irqhandler(info->evtchn,
735 blkif_interrupt,
736 IRQF_SAMPLE_RANDOM, "blkif", info);
737 if (err <= 0) {
738 xenbus_dev_fatal(dev, err,
739 "bind_evtchn_to_irqhandler failed");
740 goto fail;
741 }
742 info->irq = err;
743
744 return 0;
745fail:
746 blkif_free(info, 0);
747 return err;
748}
749
750
751
752static int talk_to_blkback(struct xenbus_device *dev,
753 struct blkfront_info *info)
754{
755 const char *message = NULL;
756 struct xenbus_transaction xbt;
757 int err;
758
759
760 err = setup_blkring(dev, info);
761 if (err)
762 goto out;
763
764again:
765 err = xenbus_transaction_start(&xbt);
766 if (err) {
767 xenbus_dev_fatal(dev, err, "starting transaction");
768 goto destroy_blkring;
769 }
770
771 err = xenbus_printf(xbt, dev->nodename,
772 "ring-ref", "%u", info->ring_ref);
773 if (err) {
774 message = "writing ring-ref";
775 goto abort_transaction;
776 }
777 err = xenbus_printf(xbt, dev->nodename,
778 "event-channel", "%u", info->evtchn);
779 if (err) {
780 message = "writing event-channel";
781 goto abort_transaction;
782 }
783 err = xenbus_printf(xbt, dev->nodename, "protocol", "%s",
784 XEN_IO_PROTO_ABI_NATIVE);
785 if (err) {
786 message = "writing protocol";
787 goto abort_transaction;
788 }
789
790 err = xenbus_transaction_end(xbt, 0);
791 if (err) {
792 if (err == -EAGAIN)
793 goto again;
794 xenbus_dev_fatal(dev, err, "completing transaction");
795 goto destroy_blkring;
796 }
797
798 xenbus_switch_state(dev, XenbusStateInitialised);
799
800 return 0;
801
802 abort_transaction:
803 xenbus_transaction_end(xbt, 1);
804 if (message)
805 xenbus_dev_fatal(dev, err, "%s", message);
806 destroy_blkring:
807 blkif_free(info, 0);
808 out:
809 return err;
810}
811
812
813
814
815
816
817
818static int blkfront_probe(struct xenbus_device *dev,
819 const struct xenbus_device_id *id)
820{
821 int err, vdevice, i;
822 struct blkfront_info *info;
823
824
825 err = xenbus_scanf(XBT_NIL, dev->nodename,
826 "virtual-device", "%i", &vdevice);
827 if (err != 1) {
828
829 err = xenbus_scanf(XBT_NIL, dev->nodename, "virtual-device-ext",
830 "%i", &vdevice);
831 if (err != 1) {
832 xenbus_dev_fatal(dev, err, "reading virtual-device");
833 return err;
834 }
835 }
836
837 if (xen_hvm_domain()) {
838 char *type;
839 int len;
840
841 if (xen_platform_pci_unplug & XEN_UNPLUG_UNNECESSARY) {
842 int major;
843
844 if (!VDEV_IS_EXTENDED(vdevice))
845 major = BLKIF_MAJOR(vdevice);
846 else
847 major = XENVBD_MAJOR;
848
849 if (major != XENVBD_MAJOR) {
850 printk(KERN_INFO
851 "%s: HVM does not support vbd %d as xen block device\n",
852 __FUNCTION__, vdevice);
853 return -ENODEV;
854 }
855 }
856
857 type = xenbus_read(XBT_NIL, dev->nodename, "device-type", &len);
858 if (IS_ERR(type))
859 return -ENODEV;
860 if (strncmp(type, "cdrom", 5) == 0) {
861 kfree(type);
862 return -ENODEV;
863 }
864 kfree(type);
865 }
866 info = kzalloc(sizeof(*info), GFP_KERNEL);
867 if (!info) {
868 xenbus_dev_fatal(dev, -ENOMEM, "allocating info structure");
869 return -ENOMEM;
870 }
871
872 mutex_init(&info->mutex);
873 info->xbdev = dev;
874 info->vdevice = vdevice;
875 info->connected = BLKIF_STATE_DISCONNECTED;
876 INIT_WORK(&info->work, blkif_restart_queue);
877
878 for (i = 0; i < BLK_RING_SIZE; i++)
879 info->shadow[i].req.id = i+1;
880 info->shadow[BLK_RING_SIZE-1].req.id = 0x0fffffff;
881
882
883 info->handle = simple_strtoul(strrchr(dev->nodename, '/')+1, NULL, 0);
884 dev_set_drvdata(&dev->dev, info);
885
886 err = talk_to_blkback(dev, info);
887 if (err) {
888 kfree(info);
889 dev_set_drvdata(&dev->dev, NULL);
890 return err;
891 }
892
893 return 0;
894}
895
896
897static int blkif_recover(struct blkfront_info *info)
898{
899 int i;
900 struct blkif_request *req;
901 struct blk_shadow *copy;
902 int j;
903
904
905 copy = kmalloc(sizeof(info->shadow),
906 GFP_NOIO | __GFP_REPEAT | __GFP_HIGH);
907 if (!copy)
908 return -ENOMEM;
909 memcpy(copy, info->shadow, sizeof(info->shadow));
910
911
912 memset(&info->shadow, 0, sizeof(info->shadow));
913 for (i = 0; i < BLK_RING_SIZE; i++)
914 info->shadow[i].req.id = i+1;
915 info->shadow_free = info->ring.req_prod_pvt;
916 info->shadow[BLK_RING_SIZE-1].req.id = 0x0fffffff;
917
918
919 for (i = 0; i < BLK_RING_SIZE; i++) {
920
921 if (!copy[i].request)
922 continue;
923
924
925 req = RING_GET_REQUEST(&info->ring, info->ring.req_prod_pvt);
926 *req = copy[i].req;
927
928
929 req->id = get_id_from_freelist(info);
930 memcpy(&info->shadow[req->id], ©[i], sizeof(copy[i]));
931
932
933 for (j = 0; j < req->nr_segments; j++)
934 gnttab_grant_foreign_access_ref(
935 req->seg[j].gref,
936 info->xbdev->otherend_id,
937 pfn_to_mfn(info->shadow[req->id].frame[j]),
938 rq_data_dir(info->shadow[req->id].request));
939 info->shadow[req->id].req = *req;
940
941 info->ring.req_prod_pvt++;
942 }
943
944 kfree(copy);
945
946 xenbus_switch_state(info->xbdev, XenbusStateConnected);
947
948 spin_lock_irq(&blkif_io_lock);
949
950
951 info->connected = BLKIF_STATE_CONNECTED;
952
953
954 flush_requests(info);
955
956
957 kick_pending_request_queues(info);
958
959 spin_unlock_irq(&blkif_io_lock);
960
961 return 0;
962}
963
964
965
966
967
968
969
970static int blkfront_resume(struct xenbus_device *dev)
971{
972 struct blkfront_info *info = dev_get_drvdata(&dev->dev);
973 int err;
974
975 dev_dbg(&dev->dev, "blkfront_resume: %s\n", dev->nodename);
976
977 blkif_free(info, info->connected == BLKIF_STATE_CONNECTED);
978
979 err = talk_to_blkback(dev, info);
980 if (info->connected == BLKIF_STATE_SUSPENDED && !err)
981 err = blkif_recover(info);
982
983 return err;
984}
985
986static void
987blkfront_closing(struct blkfront_info *info)
988{
989 struct xenbus_device *xbdev = info->xbdev;
990 struct block_device *bdev = NULL;
991
992 mutex_lock(&info->mutex);
993
994 if (xbdev->state == XenbusStateClosing) {
995 mutex_unlock(&info->mutex);
996 return;
997 }
998
999 if (info->gd)
1000 bdev = bdget_disk(info->gd, 0);
1001
1002 mutex_unlock(&info->mutex);
1003
1004 if (!bdev) {
1005 xenbus_frontend_closed(xbdev);
1006 return;
1007 }
1008
1009 mutex_lock(&bdev->bd_mutex);
1010
1011 if (bdev->bd_openers) {
1012 xenbus_dev_error(xbdev, -EBUSY,
1013 "Device in use; refusing to close");
1014 xenbus_switch_state(xbdev, XenbusStateClosing);
1015 } else {
1016 xlvbd_release_gendisk(info);
1017 xenbus_frontend_closed(xbdev);
1018 }
1019
1020 mutex_unlock(&bdev->bd_mutex);
1021 bdput(bdev);
1022}
1023
1024
1025
1026
1027
1028static void blkfront_connect(struct blkfront_info *info)
1029{
1030 unsigned long long sectors;
1031 unsigned long sector_size;
1032 unsigned int binfo;
1033 int err;
1034 int barrier;
1035
1036 switch (info->connected) {
1037 case BLKIF_STATE_CONNECTED:
1038
1039
1040
1041
1042 err = xenbus_scanf(XBT_NIL, info->xbdev->otherend,
1043 "sectors", "%Lu", §ors);
1044 if (XENBUS_EXIST_ERR(err))
1045 return;
1046 printk(KERN_INFO "Setting capacity to %Lu\n",
1047 sectors);
1048 set_capacity(info->gd, sectors);
1049 revalidate_disk(info->gd);
1050
1051
1052 case BLKIF_STATE_SUSPENDED:
1053 return;
1054
1055 default:
1056 break;
1057 }
1058
1059 dev_dbg(&info->xbdev->dev, "%s:%s.\n",
1060 __func__, info->xbdev->otherend);
1061
1062 err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
1063 "sectors", "%llu", §ors,
1064 "info", "%u", &binfo,
1065 "sector-size", "%lu", §or_size,
1066 NULL);
1067 if (err) {
1068 xenbus_dev_fatal(info->xbdev, err,
1069 "reading backend fields at %s",
1070 info->xbdev->otherend);
1071 return;
1072 }
1073
1074 err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
1075 "feature-barrier", "%lu", &barrier,
1076 NULL);
1077
1078
1079
1080
1081
1082
1083
1084
1085 info->feature_flush = 0;
1086
1087 if (!err && barrier)
1088 info->feature_flush = REQ_FLUSH | REQ_FUA;
1089
1090 err = xlvbd_alloc_gendisk(sectors, info, binfo, sector_size);
1091 if (err) {
1092 xenbus_dev_fatal(info->xbdev, err, "xlvbd_add at %s",
1093 info->xbdev->otherend);
1094 return;
1095 }
1096
1097 xenbus_switch_state(info->xbdev, XenbusStateConnected);
1098
1099
1100 spin_lock_irq(&blkif_io_lock);
1101 info->connected = BLKIF_STATE_CONNECTED;
1102 kick_pending_request_queues(info);
1103 spin_unlock_irq(&blkif_io_lock);
1104
1105 add_disk(info->gd);
1106
1107 info->is_ready = 1;
1108}
1109
1110
1111
1112
1113static void blkback_changed(struct xenbus_device *dev,
1114 enum xenbus_state backend_state)
1115{
1116 struct blkfront_info *info = dev_get_drvdata(&dev->dev);
1117
1118 dev_dbg(&dev->dev, "blkfront:blkback_changed to state %d.\n", backend_state);
1119
1120 switch (backend_state) {
1121 case XenbusStateInitialising:
1122 case XenbusStateInitWait:
1123 case XenbusStateInitialised:
1124 case XenbusStateReconfiguring:
1125 case XenbusStateReconfigured:
1126 case XenbusStateUnknown:
1127 case XenbusStateClosed:
1128 break;
1129
1130 case XenbusStateConnected:
1131 blkfront_connect(info);
1132 break;
1133
1134 case XenbusStateClosing:
1135 blkfront_closing(info);
1136 break;
1137 }
1138}
1139
1140static int blkfront_remove(struct xenbus_device *xbdev)
1141{
1142 struct blkfront_info *info = dev_get_drvdata(&xbdev->dev);
1143 struct block_device *bdev = NULL;
1144 struct gendisk *disk;
1145
1146 dev_dbg(&xbdev->dev, "%s removed", xbdev->nodename);
1147
1148 blkif_free(info, 0);
1149
1150 mutex_lock(&info->mutex);
1151
1152 disk = info->gd;
1153 if (disk)
1154 bdev = bdget_disk(disk, 0);
1155
1156 info->xbdev = NULL;
1157 mutex_unlock(&info->mutex);
1158
1159 if (!bdev) {
1160 kfree(info);
1161 return 0;
1162 }
1163
1164
1165
1166
1167
1168
1169
1170 mutex_lock(&bdev->bd_mutex);
1171 info = disk->private_data;
1172
1173 dev_warn(disk_to_dev(disk),
1174 "%s was hot-unplugged, %d stale handles\n",
1175 xbdev->nodename, bdev->bd_openers);
1176
1177 if (info && !bdev->bd_openers) {
1178 xlvbd_release_gendisk(info);
1179 disk->private_data = NULL;
1180 kfree(info);
1181 }
1182
1183 mutex_unlock(&bdev->bd_mutex);
1184 bdput(bdev);
1185
1186 return 0;
1187}
1188
1189static int blkfront_is_ready(struct xenbus_device *dev)
1190{
1191 struct blkfront_info *info = dev_get_drvdata(&dev->dev);
1192
1193 return info->is_ready && info->xbdev;
1194}
1195
1196static int blkif_open(struct block_device *bdev, fmode_t mode)
1197{
1198 struct gendisk *disk = bdev->bd_disk;
1199 struct blkfront_info *info;
1200 int err = 0;
1201
1202 mutex_lock(&blkfront_mutex);
1203
1204 info = disk->private_data;
1205 if (!info) {
1206
1207 err = -ERESTARTSYS;
1208 goto out;
1209 }
1210
1211 mutex_lock(&info->mutex);
1212
1213 if (!info->gd)
1214
1215 err = -ERESTARTSYS;
1216
1217 mutex_unlock(&info->mutex);
1218
1219out:
1220 mutex_unlock(&blkfront_mutex);
1221 return err;
1222}
1223
1224static int blkif_release(struct gendisk *disk, fmode_t mode)
1225{
1226 struct blkfront_info *info = disk->private_data;
1227 struct block_device *bdev;
1228 struct xenbus_device *xbdev;
1229
1230 mutex_lock(&blkfront_mutex);
1231
1232 bdev = bdget_disk(disk, 0);
1233 bdput(bdev);
1234
1235 if (bdev->bd_openers)
1236 goto out;
1237
1238
1239
1240
1241
1242
1243 mutex_lock(&info->mutex);
1244 xbdev = info->xbdev;
1245
1246 if (xbdev && xbdev->state == XenbusStateClosing) {
1247
1248 dev_info(disk_to_dev(bdev->bd_disk), "releasing disk\n");
1249 xlvbd_release_gendisk(info);
1250 xenbus_frontend_closed(info->xbdev);
1251 }
1252
1253 mutex_unlock(&info->mutex);
1254
1255 if (!xbdev) {
1256
1257 dev_info(disk_to_dev(bdev->bd_disk), "releasing disk\n");
1258 xlvbd_release_gendisk(info);
1259 disk->private_data = NULL;
1260 kfree(info);
1261 }
1262
1263out:
1264 mutex_unlock(&blkfront_mutex);
1265 return 0;
1266}
1267
1268static const struct block_device_operations xlvbd_block_fops =
1269{
1270 .owner = THIS_MODULE,
1271 .open = blkif_open,
1272 .release = blkif_release,
1273 .getgeo = blkif_getgeo,
1274 .ioctl = blkif_ioctl,
1275};
1276
1277
1278static const struct xenbus_device_id blkfront_ids[] = {
1279 { "vbd" },
1280 { "" }
1281};
1282
1283static struct xenbus_driver blkfront = {
1284 .name = "vbd",
1285 .owner = THIS_MODULE,
1286 .ids = blkfront_ids,
1287 .probe = blkfront_probe,
1288 .remove = blkfront_remove,
1289 .resume = blkfront_resume,
1290 .otherend_changed = blkback_changed,
1291 .is_ready = blkfront_is_ready,
1292};
1293
1294static int __init xlblk_init(void)
1295{
1296 if (!xen_domain())
1297 return -ENODEV;
1298
1299 if (register_blkdev(XENVBD_MAJOR, DEV_NAME)) {
1300 printk(KERN_WARNING "xen_blk: can't get major %d with name %s\n",
1301 XENVBD_MAJOR, DEV_NAME);
1302 return -ENODEV;
1303 }
1304
1305 return xenbus_register_frontend(&blkfront);
1306}
1307module_init(xlblk_init);
1308
1309
1310static void __exit xlblk_exit(void)
1311{
1312 return xenbus_unregister_driver(&blkfront);
1313}
1314module_exit(xlblk_exit);
1315
1316MODULE_DESCRIPTION("Xen virtual block device frontend");
1317MODULE_LICENSE("GPL");
1318MODULE_ALIAS_BLOCKDEV_MAJOR(XENVBD_MAJOR);
1319MODULE_ALIAS("xen:vbd");
1320MODULE_ALIAS("xenblk");
1321