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17#include <stdarg.h>
18#include <linux/module.h>
19#include <linux/kthread.h>
20#include <xen/events.h>
21#include <xen/grant_table.h>
22#include "common.h"
23
24struct backend_info {
25 struct xenbus_device *dev;
26 struct xen_blkif *blkif;
27 struct xenbus_watch backend_watch;
28 unsigned major;
29 unsigned minor;
30 char *mode;
31};
32
33static struct kmem_cache *xen_blkif_cachep;
34static void connect(struct backend_info *);
35static int connect_ring(struct backend_info *);
36static void backend_changed(struct xenbus_watch *, const char **,
37 unsigned int);
38
39struct xenbus_device *xen_blkbk_xenbus(struct backend_info *be)
40{
41 return be->dev;
42}
43
44static int blkback_name(struct xen_blkif *blkif, char *buf)
45{
46 char *devpath, *devname;
47 struct xenbus_device *dev = blkif->be->dev;
48
49 devpath = xenbus_read(XBT_NIL, dev->nodename, "dev", NULL);
50 if (IS_ERR(devpath))
51 return PTR_ERR(devpath);
52
53 devname = strstr(devpath, "/dev/");
54 if (devname != NULL)
55 devname += strlen("/dev/");
56 else
57 devname = devpath;
58
59 snprintf(buf, TASK_COMM_LEN, "blkback.%d.%s", blkif->domid, devname);
60 kfree(devpath);
61
62 return 0;
63}
64
65static void xen_update_blkif_status(struct xen_blkif *blkif)
66{
67 int err;
68 char name[TASK_COMM_LEN];
69
70
71 if (!blkif->irq || !blkif->vbd.bdev)
72 return;
73
74
75 if (blkif->be->dev->state == XenbusStateConnected)
76 return;
77
78
79 connect(blkif->be);
80 if (blkif->be->dev->state != XenbusStateConnected)
81 return;
82
83 err = blkback_name(blkif, name);
84 if (err) {
85 xenbus_dev_error(blkif->be->dev, err, "get blkback dev name");
86 return;
87 }
88
89 err = filemap_write_and_wait(blkif->vbd.bdev->bd_inode->i_mapping);
90 if (err) {
91 xenbus_dev_error(blkif->be->dev, err, "block flush");
92 return;
93 }
94 invalidate_inode_pages2(blkif->vbd.bdev->bd_inode->i_mapping);
95
96 blkif->xenblkd = kthread_run(xen_blkif_schedule, blkif, "%s", name);
97 if (IS_ERR(blkif->xenblkd)) {
98 err = PTR_ERR(blkif->xenblkd);
99 blkif->xenblkd = NULL;
100 xenbus_dev_error(blkif->be->dev, err, "start xenblkd");
101 return;
102 }
103}
104
105static struct xen_blkif *xen_blkif_alloc(domid_t domid)
106{
107 struct xen_blkif *blkif;
108 struct pending_req *req, *n;
109 int i, j;
110
111 BUILD_BUG_ON(MAX_INDIRECT_PAGES > BLKIF_MAX_INDIRECT_PAGES_PER_REQUEST);
112
113 blkif = kmem_cache_zalloc(xen_blkif_cachep, GFP_KERNEL);
114 if (!blkif)
115 return ERR_PTR(-ENOMEM);
116
117 blkif->domid = domid;
118 spin_lock_init(&blkif->blk_ring_lock);
119 atomic_set(&blkif->refcnt, 1);
120 init_waitqueue_head(&blkif->wq);
121 init_completion(&blkif->drain_complete);
122 atomic_set(&blkif->drain, 0);
123 blkif->st_print = jiffies;
124 init_waitqueue_head(&blkif->waiting_to_free);
125 blkif->persistent_gnts.rb_node = NULL;
126 spin_lock_init(&blkif->free_pages_lock);
127 INIT_LIST_HEAD(&blkif->free_pages);
128 blkif->free_pages_num = 0;
129 atomic_set(&blkif->persistent_gnt_in_use, 0);
130
131 INIT_LIST_HEAD(&blkif->pending_free);
132
133 for (i = 0; i < XEN_BLKIF_REQS; i++) {
134 req = kzalloc(sizeof(*req), GFP_KERNEL);
135 if (!req)
136 goto fail;
137 list_add_tail(&req->free_list,
138 &blkif->pending_free);
139 for (j = 0; j < MAX_INDIRECT_SEGMENTS; j++) {
140 req->segments[j] = kzalloc(sizeof(*req->segments[0]),
141 GFP_KERNEL);
142 if (!req->segments[j])
143 goto fail;
144 }
145 for (j = 0; j < MAX_INDIRECT_PAGES; j++) {
146 req->indirect_pages[j] = kzalloc(sizeof(*req->indirect_pages[0]),
147 GFP_KERNEL);
148 if (!req->indirect_pages[j])
149 goto fail;
150 }
151 }
152 spin_lock_init(&blkif->pending_free_lock);
153 init_waitqueue_head(&blkif->pending_free_wq);
154 init_waitqueue_head(&blkif->shutdown_wq);
155
156 return blkif;
157
158fail:
159 list_for_each_entry_safe(req, n, &blkif->pending_free, free_list) {
160 list_del(&req->free_list);
161 for (j = 0; j < MAX_INDIRECT_SEGMENTS; j++) {
162 if (!req->segments[j])
163 break;
164 kfree(req->segments[j]);
165 }
166 for (j = 0; j < MAX_INDIRECT_PAGES; j++) {
167 if (!req->indirect_pages[j])
168 break;
169 kfree(req->indirect_pages[j]);
170 }
171 kfree(req);
172 }
173
174 kmem_cache_free(xen_blkif_cachep, blkif);
175
176 return ERR_PTR(-ENOMEM);
177}
178
179static int xen_blkif_map(struct xen_blkif *blkif, unsigned long shared_page,
180 unsigned int evtchn)
181{
182 int err;
183
184
185 if (blkif->irq)
186 return 0;
187
188 err = xenbus_map_ring_valloc(blkif->be->dev, shared_page, &blkif->blk_ring);
189 if (err < 0)
190 return err;
191
192 switch (blkif->blk_protocol) {
193 case BLKIF_PROTOCOL_NATIVE:
194 {
195 struct blkif_sring *sring;
196 sring = (struct blkif_sring *)blkif->blk_ring;
197 BACK_RING_INIT(&blkif->blk_rings.native, sring, PAGE_SIZE);
198 break;
199 }
200 case BLKIF_PROTOCOL_X86_32:
201 {
202 struct blkif_x86_32_sring *sring_x86_32;
203 sring_x86_32 = (struct blkif_x86_32_sring *)blkif->blk_ring;
204 BACK_RING_INIT(&blkif->blk_rings.x86_32, sring_x86_32, PAGE_SIZE);
205 break;
206 }
207 case BLKIF_PROTOCOL_X86_64:
208 {
209 struct blkif_x86_64_sring *sring_x86_64;
210 sring_x86_64 = (struct blkif_x86_64_sring *)blkif->blk_ring;
211 BACK_RING_INIT(&blkif->blk_rings.x86_64, sring_x86_64, PAGE_SIZE);
212 break;
213 }
214 default:
215 BUG();
216 }
217
218 err = bind_interdomain_evtchn_to_irqhandler(blkif->domid, evtchn,
219 xen_blkif_be_int, 0,
220 "blkif-backend", blkif);
221 if (err < 0) {
222 xenbus_unmap_ring_vfree(blkif->be->dev, blkif->blk_ring);
223 blkif->blk_rings.common.sring = NULL;
224 return err;
225 }
226 blkif->irq = err;
227
228 return 0;
229}
230
231static void xen_blkif_disconnect(struct xen_blkif *blkif)
232{
233 if (blkif->xenblkd) {
234 kthread_stop(blkif->xenblkd);
235 wake_up(&blkif->shutdown_wq);
236 blkif->xenblkd = NULL;
237 }
238
239 atomic_dec(&blkif->refcnt);
240 wait_event(blkif->waiting_to_free, atomic_read(&blkif->refcnt) == 0);
241 atomic_inc(&blkif->refcnt);
242
243 if (blkif->irq) {
244 unbind_from_irqhandler(blkif->irq, blkif);
245 blkif->irq = 0;
246 }
247
248 if (blkif->blk_rings.common.sring) {
249 xenbus_unmap_ring_vfree(blkif->be->dev, blkif->blk_ring);
250 blkif->blk_rings.common.sring = NULL;
251 }
252}
253
254static void xen_blkif_free(struct xen_blkif *blkif)
255{
256 struct pending_req *req, *n;
257 int i = 0, j;
258
259 if (!atomic_dec_and_test(&blkif->refcnt))
260 BUG();
261
262
263 list_for_each_entry_safe(req, n, &blkif->pending_free, free_list) {
264 list_del(&req->free_list);
265
266 for (j = 0; j < MAX_INDIRECT_SEGMENTS; j++)
267 kfree(req->segments[j]);
268
269 for (j = 0; j < MAX_INDIRECT_PAGES; j++)
270 kfree(req->indirect_pages[j]);
271
272 kfree(req);
273 i++;
274 }
275
276 WARN_ON(i != XEN_BLKIF_REQS);
277
278 kmem_cache_free(xen_blkif_cachep, blkif);
279}
280
281int __init xen_blkif_interface_init(void)
282{
283 xen_blkif_cachep = kmem_cache_create("blkif_cache",
284 sizeof(struct xen_blkif),
285 0, 0, NULL);
286 if (!xen_blkif_cachep)
287 return -ENOMEM;
288
289 return 0;
290}
291
292
293
294
295
296#define VBD_SHOW(name, format, args...) \
297 static ssize_t show_##name(struct device *_dev, \
298 struct device_attribute *attr, \
299 char *buf) \
300 { \
301 struct xenbus_device *dev = to_xenbus_device(_dev); \
302 struct backend_info *be = dev_get_drvdata(&dev->dev); \
303 \
304 return sprintf(buf, format, ##args); \
305 } \
306 static DEVICE_ATTR(name, S_IRUGO, show_##name, NULL)
307
308VBD_SHOW(oo_req, "%llu\n", be->blkif->st_oo_req);
309VBD_SHOW(rd_req, "%llu\n", be->blkif->st_rd_req);
310VBD_SHOW(wr_req, "%llu\n", be->blkif->st_wr_req);
311VBD_SHOW(f_req, "%llu\n", be->blkif->st_f_req);
312VBD_SHOW(ds_req, "%llu\n", be->blkif->st_ds_req);
313VBD_SHOW(rd_sect, "%llu\n", be->blkif->st_rd_sect);
314VBD_SHOW(wr_sect, "%llu\n", be->blkif->st_wr_sect);
315
316static struct attribute *xen_vbdstat_attrs[] = {
317 &dev_attr_oo_req.attr,
318 &dev_attr_rd_req.attr,
319 &dev_attr_wr_req.attr,
320 &dev_attr_f_req.attr,
321 &dev_attr_ds_req.attr,
322 &dev_attr_rd_sect.attr,
323 &dev_attr_wr_sect.attr,
324 NULL
325};
326
327static struct attribute_group xen_vbdstat_group = {
328 .name = "statistics",
329 .attrs = xen_vbdstat_attrs,
330};
331
332VBD_SHOW(physical_device, "%x:%x\n", be->major, be->minor);
333VBD_SHOW(mode, "%s\n", be->mode);
334
335static int xenvbd_sysfs_addif(struct xenbus_device *dev)
336{
337 int error;
338
339 error = device_create_file(&dev->dev, &dev_attr_physical_device);
340 if (error)
341 goto fail1;
342
343 error = device_create_file(&dev->dev, &dev_attr_mode);
344 if (error)
345 goto fail2;
346
347 error = sysfs_create_group(&dev->dev.kobj, &xen_vbdstat_group);
348 if (error)
349 goto fail3;
350
351 return 0;
352
353fail3: sysfs_remove_group(&dev->dev.kobj, &xen_vbdstat_group);
354fail2: device_remove_file(&dev->dev, &dev_attr_mode);
355fail1: device_remove_file(&dev->dev, &dev_attr_physical_device);
356 return error;
357}
358
359static void xenvbd_sysfs_delif(struct xenbus_device *dev)
360{
361 sysfs_remove_group(&dev->dev.kobj, &xen_vbdstat_group);
362 device_remove_file(&dev->dev, &dev_attr_mode);
363 device_remove_file(&dev->dev, &dev_attr_physical_device);
364}
365
366
367static void xen_vbd_free(struct xen_vbd *vbd)
368{
369 if (vbd->bdev)
370 blkdev_put(vbd->bdev, vbd->readonly ? FMODE_READ : FMODE_WRITE);
371 vbd->bdev = NULL;
372}
373
374static int xen_vbd_create(struct xen_blkif *blkif, blkif_vdev_t handle,
375 unsigned major, unsigned minor, int readonly,
376 int cdrom)
377{
378 struct xen_vbd *vbd;
379 struct block_device *bdev;
380 struct request_queue *q;
381
382 vbd = &blkif->vbd;
383 vbd->handle = handle;
384 vbd->readonly = readonly;
385 vbd->type = 0;
386
387 vbd->pdevice = MKDEV(major, minor);
388
389 bdev = blkdev_get_by_dev(vbd->pdevice, vbd->readonly ?
390 FMODE_READ : FMODE_WRITE, NULL);
391
392 if (IS_ERR(bdev)) {
393 DPRINTK("xen_vbd_create: device %08x could not be opened.\n",
394 vbd->pdevice);
395 return -ENOENT;
396 }
397
398 vbd->bdev = bdev;
399 if (vbd->bdev->bd_disk == NULL) {
400 DPRINTK("xen_vbd_create: device %08x doesn't exist.\n",
401 vbd->pdevice);
402 xen_vbd_free(vbd);
403 return -ENOENT;
404 }
405 vbd->size = vbd_sz(vbd);
406
407 if (vbd->bdev->bd_disk->flags & GENHD_FL_CD || cdrom)
408 vbd->type |= VDISK_CDROM;
409 if (vbd->bdev->bd_disk->flags & GENHD_FL_REMOVABLE)
410 vbd->type |= VDISK_REMOVABLE;
411
412 q = bdev_get_queue(bdev);
413 if (q && q->flush_flags)
414 vbd->flush_support = true;
415
416 if (q && blk_queue_secdiscard(q))
417 vbd->discard_secure = true;
418
419 DPRINTK("Successful creation of handle=%04x (dom=%u)\n",
420 handle, blkif->domid);
421 return 0;
422}
423static int xen_blkbk_remove(struct xenbus_device *dev)
424{
425 struct backend_info *be = dev_get_drvdata(&dev->dev);
426
427 DPRINTK("");
428
429 if (be->major || be->minor)
430 xenvbd_sysfs_delif(dev);
431
432 if (be->backend_watch.node) {
433 unregister_xenbus_watch(&be->backend_watch);
434 kfree(be->backend_watch.node);
435 be->backend_watch.node = NULL;
436 }
437
438 if (be->blkif) {
439 xen_blkif_disconnect(be->blkif);
440 xen_vbd_free(&be->blkif->vbd);
441 xen_blkif_free(be->blkif);
442 be->blkif = NULL;
443 }
444
445 kfree(be->mode);
446 kfree(be);
447 dev_set_drvdata(&dev->dev, NULL);
448 return 0;
449}
450
451int xen_blkbk_flush_diskcache(struct xenbus_transaction xbt,
452 struct backend_info *be, int state)
453{
454 struct xenbus_device *dev = be->dev;
455 int err;
456
457 err = xenbus_printf(xbt, dev->nodename, "feature-flush-cache",
458 "%d", state);
459 if (err)
460 dev_warn(&dev->dev, "writing feature-flush-cache (%d)", err);
461
462 return err;
463}
464
465static void xen_blkbk_discard(struct xenbus_transaction xbt, struct backend_info *be)
466{
467 struct xenbus_device *dev = be->dev;
468 struct xen_blkif *blkif = be->blkif;
469 int err;
470 int state = 0;
471 struct block_device *bdev = be->blkif->vbd.bdev;
472 struct request_queue *q = bdev_get_queue(bdev);
473
474 if (blk_queue_discard(q)) {
475 err = xenbus_printf(xbt, dev->nodename,
476 "discard-granularity", "%u",
477 q->limits.discard_granularity);
478 if (err) {
479 dev_warn(&dev->dev, "writing discard-granularity (%d)", err);
480 return;
481 }
482 err = xenbus_printf(xbt, dev->nodename,
483 "discard-alignment", "%u",
484 q->limits.discard_alignment);
485 if (err) {
486 dev_warn(&dev->dev, "writing discard-alignment (%d)", err);
487 return;
488 }
489 state = 1;
490
491 err = xenbus_printf(xbt, dev->nodename,
492 "discard-secure", "%d",
493 blkif->vbd.discard_secure);
494 if (err) {
495 dev_warn(&dev->dev, "writing discard-secure (%d)", err);
496 return;
497 }
498 }
499 err = xenbus_printf(xbt, dev->nodename, "feature-discard",
500 "%d", state);
501 if (err)
502 dev_warn(&dev->dev, "writing feature-discard (%d)", err);
503}
504int xen_blkbk_barrier(struct xenbus_transaction xbt,
505 struct backend_info *be, int state)
506{
507 struct xenbus_device *dev = be->dev;
508 int err;
509
510 err = xenbus_printf(xbt, dev->nodename, "feature-barrier",
511 "%d", state);
512 if (err)
513 dev_warn(&dev->dev, "writing feature-barrier (%d)", err);
514
515 return err;
516}
517
518
519
520
521
522
523static int xen_blkbk_probe(struct xenbus_device *dev,
524 const struct xenbus_device_id *id)
525{
526 int err;
527 struct backend_info *be = kzalloc(sizeof(struct backend_info),
528 GFP_KERNEL);
529 if (!be) {
530 xenbus_dev_fatal(dev, -ENOMEM,
531 "allocating backend structure");
532 return -ENOMEM;
533 }
534 be->dev = dev;
535 dev_set_drvdata(&dev->dev, be);
536
537 be->blkif = xen_blkif_alloc(dev->otherend_id);
538 if (IS_ERR(be->blkif)) {
539 err = PTR_ERR(be->blkif);
540 be->blkif = NULL;
541 xenbus_dev_fatal(dev, err, "creating block interface");
542 goto fail;
543 }
544
545
546 be->blkif->be = be;
547
548 err = xenbus_watch_pathfmt(dev, &be->backend_watch, backend_changed,
549 "%s/%s", dev->nodename, "physical-device");
550 if (err)
551 goto fail;
552
553 err = xenbus_switch_state(dev, XenbusStateInitWait);
554 if (err)
555 goto fail;
556
557 return 0;
558
559fail:
560 DPRINTK("failed");
561 xen_blkbk_remove(dev);
562 return err;
563}
564
565
566
567
568
569
570
571static void backend_changed(struct xenbus_watch *watch,
572 const char **vec, unsigned int len)
573{
574 int err;
575 unsigned major;
576 unsigned minor;
577 struct backend_info *be
578 = container_of(watch, struct backend_info, backend_watch);
579 struct xenbus_device *dev = be->dev;
580 int cdrom = 0;
581 unsigned long handle;
582 char *device_type;
583
584 DPRINTK("");
585
586 err = xenbus_scanf(XBT_NIL, dev->nodename, "physical-device", "%x:%x",
587 &major, &minor);
588 if (XENBUS_EXIST_ERR(err)) {
589
590
591
592
593
594 return;
595 }
596 if (err != 2) {
597 xenbus_dev_fatal(dev, err, "reading physical-device");
598 return;
599 }
600
601 if (be->major | be->minor) {
602 if (be->major != major || be->minor != minor)
603 pr_warn(DRV_PFX "changing physical device (from %x:%x to %x:%x) not supported.\n",
604 be->major, be->minor, major, minor);
605 return;
606 }
607
608 be->mode = xenbus_read(XBT_NIL, dev->nodename, "mode", NULL);
609 if (IS_ERR(be->mode)) {
610 err = PTR_ERR(be->mode);
611 be->mode = NULL;
612 xenbus_dev_fatal(dev, err, "reading mode");
613 return;
614 }
615
616 device_type = xenbus_read(XBT_NIL, dev->otherend, "device-type", NULL);
617 if (!IS_ERR(device_type)) {
618 cdrom = strcmp(device_type, "cdrom") == 0;
619 kfree(device_type);
620 }
621
622
623 err = kstrtoul(strrchr(dev->otherend, '/') + 1, 0, &handle);
624 if (err)
625 return;
626
627 be->major = major;
628 be->minor = minor;
629
630 err = xen_vbd_create(be->blkif, handle, major, minor,
631 !strchr(be->mode, 'w'), cdrom);
632
633 if (err)
634 xenbus_dev_fatal(dev, err, "creating vbd structure");
635 else {
636 err = xenvbd_sysfs_addif(dev);
637 if (err) {
638 xen_vbd_free(&be->blkif->vbd);
639 xenbus_dev_fatal(dev, err, "creating sysfs entries");
640 }
641 }
642
643 if (err) {
644 kfree(be->mode);
645 be->mode = NULL;
646 be->major = 0;
647 be->minor = 0;
648 } else {
649
650 xen_update_blkif_status(be->blkif);
651 }
652}
653
654
655
656
657
658static void frontend_changed(struct xenbus_device *dev,
659 enum xenbus_state frontend_state)
660{
661 struct backend_info *be = dev_get_drvdata(&dev->dev);
662 int err;
663
664 DPRINTK("%s", xenbus_strstate(frontend_state));
665
666 switch (frontend_state) {
667 case XenbusStateInitialising:
668 if (dev->state == XenbusStateClosed) {
669 pr_info(DRV_PFX "%s: prepare for reconnect\n",
670 dev->nodename);
671 xenbus_switch_state(dev, XenbusStateInitWait);
672 }
673 break;
674
675 case XenbusStateInitialised:
676 case XenbusStateConnected:
677
678
679
680
681
682 if (dev->state == XenbusStateConnected)
683 break;
684
685
686
687
688
689 xen_blkif_disconnect(be->blkif);
690
691 err = connect_ring(be);
692 if (err)
693 break;
694 xen_update_blkif_status(be->blkif);
695 break;
696
697 case XenbusStateClosing:
698 xenbus_switch_state(dev, XenbusStateClosing);
699 break;
700
701 case XenbusStateClosed:
702 xen_blkif_disconnect(be->blkif);
703 xenbus_switch_state(dev, XenbusStateClosed);
704 if (xenbus_dev_is_online(dev))
705 break;
706
707 case XenbusStateUnknown:
708
709 device_unregister(&dev->dev);
710 break;
711
712 default:
713 xenbus_dev_fatal(dev, -EINVAL, "saw state %d at frontend",
714 frontend_state);
715 break;
716 }
717}
718
719
720
721
722
723
724
725
726
727static void connect(struct backend_info *be)
728{
729 struct xenbus_transaction xbt;
730 int err;
731 struct xenbus_device *dev = be->dev;
732
733 DPRINTK("%s", dev->otherend);
734
735
736again:
737 err = xenbus_transaction_start(&xbt);
738 if (err) {
739 xenbus_dev_fatal(dev, err, "starting transaction");
740 return;
741 }
742
743
744 xen_blkbk_flush_diskcache(xbt, be, be->blkif->vbd.flush_support);
745
746 xen_blkbk_discard(xbt, be);
747
748 xen_blkbk_barrier(xbt, be, be->blkif->vbd.flush_support);
749
750 err = xenbus_printf(xbt, dev->nodename, "feature-persistent", "%u", 1);
751 if (err) {
752 xenbus_dev_fatal(dev, err, "writing %s/feature-persistent",
753 dev->nodename);
754 goto abort;
755 }
756 err = xenbus_printf(xbt, dev->nodename, "feature-max-indirect-segments", "%u",
757 MAX_INDIRECT_SEGMENTS);
758 if (err)
759 dev_warn(&dev->dev, "writing %s/feature-max-indirect-segments (%d)",
760 dev->nodename, err);
761
762 err = xenbus_printf(xbt, dev->nodename, "sectors", "%llu",
763 (unsigned long long)vbd_sz(&be->blkif->vbd));
764 if (err) {
765 xenbus_dev_fatal(dev, err, "writing %s/sectors",
766 dev->nodename);
767 goto abort;
768 }
769
770
771 err = xenbus_printf(xbt, dev->nodename, "info", "%u",
772 be->blkif->vbd.type |
773 (be->blkif->vbd.readonly ? VDISK_READONLY : 0));
774 if (err) {
775 xenbus_dev_fatal(dev, err, "writing %s/info",
776 dev->nodename);
777 goto abort;
778 }
779 err = xenbus_printf(xbt, dev->nodename, "sector-size", "%lu",
780 (unsigned long)
781 bdev_logical_block_size(be->blkif->vbd.bdev));
782 if (err) {
783 xenbus_dev_fatal(dev, err, "writing %s/sector-size",
784 dev->nodename);
785 goto abort;
786 }
787 err = xenbus_printf(xbt, dev->nodename, "physical-sector-size", "%u",
788 bdev_physical_block_size(be->blkif->vbd.bdev));
789 if (err)
790 xenbus_dev_error(dev, err, "writing %s/physical-sector-size",
791 dev->nodename);
792
793 err = xenbus_transaction_end(xbt, 0);
794 if (err == -EAGAIN)
795 goto again;
796 if (err)
797 xenbus_dev_fatal(dev, err, "ending transaction");
798
799 err = xenbus_switch_state(dev, XenbusStateConnected);
800 if (err)
801 xenbus_dev_fatal(dev, err, "%s: switching to Connected state",
802 dev->nodename);
803
804 return;
805 abort:
806 xenbus_transaction_end(xbt, 1);
807}
808
809
810static int connect_ring(struct backend_info *be)
811{
812 struct xenbus_device *dev = be->dev;
813 unsigned long ring_ref;
814 unsigned int evtchn;
815 unsigned int pers_grants;
816 char protocol[64] = "";
817 int err;
818
819 DPRINTK("%s", dev->otherend);
820
821 err = xenbus_gather(XBT_NIL, dev->otherend, "ring-ref", "%lu",
822 &ring_ref, "event-channel", "%u", &evtchn, NULL);
823 if (err) {
824 xenbus_dev_fatal(dev, err,
825 "reading %s/ring-ref and event-channel",
826 dev->otherend);
827 return err;
828 }
829
830 be->blkif->blk_protocol = BLKIF_PROTOCOL_NATIVE;
831 err = xenbus_gather(XBT_NIL, dev->otherend, "protocol",
832 "%63s", protocol, NULL);
833 if (err)
834 strcpy(protocol, "unspecified, assuming native");
835 else if (0 == strcmp(protocol, XEN_IO_PROTO_ABI_NATIVE))
836 be->blkif->blk_protocol = BLKIF_PROTOCOL_NATIVE;
837 else if (0 == strcmp(protocol, XEN_IO_PROTO_ABI_X86_32))
838 be->blkif->blk_protocol = BLKIF_PROTOCOL_X86_32;
839 else if (0 == strcmp(protocol, XEN_IO_PROTO_ABI_X86_64))
840 be->blkif->blk_protocol = BLKIF_PROTOCOL_X86_64;
841 else {
842 xenbus_dev_fatal(dev, err, "unknown fe protocol %s", protocol);
843 return -1;
844 }
845 err = xenbus_gather(XBT_NIL, dev->otherend,
846 "feature-persistent", "%u",
847 &pers_grants, NULL);
848 if (err)
849 pers_grants = 0;
850
851 be->blkif->vbd.feature_gnt_persistent = pers_grants;
852 be->blkif->vbd.overflow_max_grants = 0;
853
854 pr_info(DRV_PFX "ring-ref %ld, event-channel %d, protocol %d (%s) %s\n",
855 ring_ref, evtchn, be->blkif->blk_protocol, protocol,
856 pers_grants ? "persistent grants" : "");
857
858
859 err = xen_blkif_map(be->blkif, ring_ref, evtchn);
860 if (err) {
861 xenbus_dev_fatal(dev, err, "mapping ring-ref %lu port %u",
862 ring_ref, evtchn);
863 return err;
864 }
865
866 return 0;
867}
868
869
870
871
872
873static const struct xenbus_device_id xen_blkbk_ids[] = {
874 { "vbd" },
875 { "" }
876};
877
878
879static DEFINE_XENBUS_DRIVER(xen_blkbk, ,
880 .probe = xen_blkbk_probe,
881 .remove = xen_blkbk_remove,
882 .otherend_changed = frontend_changed
883);
884
885
886int xen_blkif_xenbus_init(void)
887{
888 return xenbus_register_backend(&xen_blkbk_driver);
889}
890
