1 | // SPDX-License-Identifier: GPL-2.0-or-later |
2 | /* Xenbus code for blkif backend |
3 | Copyright (C) 2005 Rusty Russell <rusty@rustcorp.com.au> |
4 | Copyright (C) 2005 XenSource Ltd |
5 | |
6 | |
7 | */ |
8 | |
9 | #define pr_fmt(fmt) "xen-blkback: " fmt |
10 | |
11 | #include <linux/module.h> |
12 | #include <linux/kthread.h> |
13 | #include <linux/pagemap.h> |
14 | #include <xen/events.h> |
15 | #include <xen/grant_table.h> |
16 | #include "common.h" |
17 | |
18 | /* On the XenBus the max length of 'ring-ref%u'. */ |
19 | #define RINGREF_NAME_LEN (20) |
20 | |
21 | struct backend_info { |
22 | struct xenbus_device *dev; |
23 | struct xen_blkif *blkif; |
24 | struct xenbus_watch backend_watch; |
25 | unsigned major; |
26 | unsigned minor; |
27 | char *mode; |
28 | }; |
29 | |
30 | static struct kmem_cache *xen_blkif_cachep; |
31 | static void connect(struct backend_info *); |
32 | static int connect_ring(struct backend_info *); |
33 | static void backend_changed(struct xenbus_watch *, const char *, |
34 | const char *); |
35 | static void xen_blkif_free(struct xen_blkif *blkif); |
36 | static void xen_vbd_free(struct xen_vbd *vbd); |
37 | |
38 | struct xenbus_device *xen_blkbk_xenbus(struct backend_info *be) |
39 | { |
40 | return be->dev; |
41 | } |
42 | |
43 | /* |
44 | * The last request could free the device from softirq context and |
45 | * xen_blkif_free() can sleep. |
46 | */ |
47 | static void xen_blkif_deferred_free(struct work_struct *work) |
48 | { |
49 | struct xen_blkif *blkif; |
50 | |
51 | blkif = container_of(work, struct xen_blkif, free_work); |
52 | xen_blkif_free(blkif); |
53 | } |
54 | |
55 | static int blkback_name(struct xen_blkif *blkif, char *buf) |
56 | { |
57 | char *devpath, *devname; |
58 | struct xenbus_device *dev = blkif->be->dev; |
59 | |
60 | devpath = xenbus_read(XBT_NIL, dir: dev->nodename, node: "dev" , NULL); |
61 | if (IS_ERR(devpath)) |
62 | return PTR_ERR(devpath); |
63 | |
64 | devname = strstr(devpath, "/dev/" ); |
65 | if (devname != NULL) |
66 | devname += strlen("/dev/" ); |
67 | else |
68 | devname = devpath; |
69 | |
70 | snprintf(buf, TASK_COMM_LEN, "%d.%s" , blkif->domid, devname); |
71 | kfree(devpath); |
72 | |
73 | return 0; |
74 | } |
75 | |
76 | static void xen_update_blkif_status(struct xen_blkif *blkif) |
77 | { |
78 | int err; |
79 | char name[TASK_COMM_LEN]; |
80 | struct xen_blkif_ring *ring; |
81 | int i; |
82 | |
83 | /* Not ready to connect? */ |
84 | if (!blkif->rings || !blkif->rings[0].irq || !blkif->vbd.bdev_file) |
85 | return; |
86 | |
87 | /* Already connected? */ |
88 | if (blkif->be->dev->state == XenbusStateConnected) |
89 | return; |
90 | |
91 | /* Attempt to connect: exit if we fail to. */ |
92 | connect(blkif->be); |
93 | if (blkif->be->dev->state != XenbusStateConnected) |
94 | return; |
95 | |
96 | err = blkback_name(blkif, buf: name); |
97 | if (err) { |
98 | xenbus_dev_error(dev: blkif->be->dev, err, fmt: "get blkback dev name" ); |
99 | return; |
100 | } |
101 | |
102 | err = sync_blockdev(bdev: file_bdev(bdev_file: blkif->vbd.bdev_file)); |
103 | if (err) { |
104 | xenbus_dev_error(dev: blkif->be->dev, err, fmt: "block flush" ); |
105 | return; |
106 | } |
107 | invalidate_inode_pages2(mapping: blkif->vbd.bdev_file->f_mapping); |
108 | |
109 | for (i = 0; i < blkif->nr_rings; i++) { |
110 | ring = &blkif->rings[i]; |
111 | ring->xenblkd = kthread_run(xen_blkif_schedule, ring, "%s-%d" , name, i); |
112 | if (IS_ERR(ptr: ring->xenblkd)) { |
113 | err = PTR_ERR(ptr: ring->xenblkd); |
114 | ring->xenblkd = NULL; |
115 | xenbus_dev_fatal(dev: blkif->be->dev, err, |
116 | fmt: "start %s-%d xenblkd" , name, i); |
117 | goto out; |
118 | } |
119 | } |
120 | return; |
121 | |
122 | out: |
123 | while (--i >= 0) { |
124 | ring = &blkif->rings[i]; |
125 | kthread_stop(k: ring->xenblkd); |
126 | } |
127 | return; |
128 | } |
129 | |
130 | static int xen_blkif_alloc_rings(struct xen_blkif *blkif) |
131 | { |
132 | unsigned int r; |
133 | |
134 | blkif->rings = kcalloc(n: blkif->nr_rings, size: sizeof(struct xen_blkif_ring), |
135 | GFP_KERNEL); |
136 | if (!blkif->rings) |
137 | return -ENOMEM; |
138 | |
139 | for (r = 0; r < blkif->nr_rings; r++) { |
140 | struct xen_blkif_ring *ring = &blkif->rings[r]; |
141 | |
142 | spin_lock_init(&ring->blk_ring_lock); |
143 | init_waitqueue_head(&ring->wq); |
144 | INIT_LIST_HEAD(list: &ring->pending_free); |
145 | INIT_LIST_HEAD(list: &ring->persistent_purge_list); |
146 | INIT_WORK(&ring->persistent_purge_work, xen_blkbk_unmap_purged_grants); |
147 | gnttab_page_cache_init(cache: &ring->free_pages); |
148 | |
149 | spin_lock_init(&ring->pending_free_lock); |
150 | init_waitqueue_head(&ring->pending_free_wq); |
151 | init_waitqueue_head(&ring->shutdown_wq); |
152 | ring->blkif = blkif; |
153 | ring->st_print = jiffies; |
154 | ring->active = true; |
155 | } |
156 | |
157 | return 0; |
158 | } |
159 | |
160 | /* Enable the persistent grants feature. */ |
161 | static bool feature_persistent = true; |
162 | module_param(feature_persistent, bool, 0644); |
163 | MODULE_PARM_DESC(feature_persistent, "Enables the persistent grants feature" ); |
164 | |
165 | static struct xen_blkif *xen_blkif_alloc(domid_t domid) |
166 | { |
167 | struct xen_blkif *blkif; |
168 | |
169 | BUILD_BUG_ON(MAX_INDIRECT_PAGES > BLKIF_MAX_INDIRECT_PAGES_PER_REQUEST); |
170 | |
171 | blkif = kmem_cache_zalloc(k: xen_blkif_cachep, GFP_KERNEL); |
172 | if (!blkif) |
173 | return ERR_PTR(error: -ENOMEM); |
174 | |
175 | blkif->domid = domid; |
176 | atomic_set(v: &blkif->refcnt, i: 1); |
177 | init_completion(x: &blkif->drain_complete); |
178 | |
179 | /* |
180 | * Because freeing back to the cache may be deferred, it is not |
181 | * safe to unload the module (and hence destroy the cache) until |
182 | * this has completed. To prevent premature unloading, take an |
183 | * extra module reference here and release only when the object |
184 | * has been freed back to the cache. |
185 | */ |
186 | __module_get(THIS_MODULE); |
187 | INIT_WORK(&blkif->free_work, xen_blkif_deferred_free); |
188 | |
189 | return blkif; |
190 | } |
191 | |
192 | static int xen_blkif_map(struct xen_blkif_ring *ring, grant_ref_t *gref, |
193 | unsigned int nr_grefs, unsigned int evtchn) |
194 | { |
195 | int err; |
196 | struct xen_blkif *blkif = ring->blkif; |
197 | const struct blkif_common_sring *sring_common; |
198 | RING_IDX rsp_prod, req_prod; |
199 | unsigned int size; |
200 | |
201 | /* Already connected through? */ |
202 | if (ring->irq) |
203 | return 0; |
204 | |
205 | err = xenbus_map_ring_valloc(dev: blkif->be->dev, gnt_refs: gref, nr_grefs, |
206 | vaddr: &ring->blk_ring); |
207 | if (err < 0) |
208 | return err; |
209 | |
210 | sring_common = (struct blkif_common_sring *)ring->blk_ring; |
211 | rsp_prod = READ_ONCE(sring_common->rsp_prod); |
212 | req_prod = READ_ONCE(sring_common->req_prod); |
213 | |
214 | switch (blkif->blk_protocol) { |
215 | case BLKIF_PROTOCOL_NATIVE: |
216 | { |
217 | struct blkif_sring *sring_native = |
218 | (struct blkif_sring *)ring->blk_ring; |
219 | |
220 | BACK_RING_ATTACH(&ring->blk_rings.native, sring_native, |
221 | rsp_prod, XEN_PAGE_SIZE * nr_grefs); |
222 | size = __RING_SIZE(sring_native, XEN_PAGE_SIZE * nr_grefs); |
223 | break; |
224 | } |
225 | case BLKIF_PROTOCOL_X86_32: |
226 | { |
227 | struct blkif_x86_32_sring *sring_x86_32 = |
228 | (struct blkif_x86_32_sring *)ring->blk_ring; |
229 | |
230 | BACK_RING_ATTACH(&ring->blk_rings.x86_32, sring_x86_32, |
231 | rsp_prod, XEN_PAGE_SIZE * nr_grefs); |
232 | size = __RING_SIZE(sring_x86_32, XEN_PAGE_SIZE * nr_grefs); |
233 | break; |
234 | } |
235 | case BLKIF_PROTOCOL_X86_64: |
236 | { |
237 | struct blkif_x86_64_sring *sring_x86_64 = |
238 | (struct blkif_x86_64_sring *)ring->blk_ring; |
239 | |
240 | BACK_RING_ATTACH(&ring->blk_rings.x86_64, sring_x86_64, |
241 | rsp_prod, XEN_PAGE_SIZE * nr_grefs); |
242 | size = __RING_SIZE(sring_x86_64, XEN_PAGE_SIZE * nr_grefs); |
243 | break; |
244 | } |
245 | default: |
246 | BUG(); |
247 | } |
248 | |
249 | err = -EIO; |
250 | if (req_prod - rsp_prod > size) |
251 | goto fail; |
252 | |
253 | err = bind_interdomain_evtchn_to_irqhandler_lateeoi(dev: blkif->be->dev, |
254 | remote_port: evtchn, handler: xen_blkif_be_int, irqflags: 0, devname: "blkif-backend" , dev_id: ring); |
255 | if (err < 0) |
256 | goto fail; |
257 | ring->irq = err; |
258 | |
259 | return 0; |
260 | |
261 | fail: |
262 | xenbus_unmap_ring_vfree(dev: blkif->be->dev, vaddr: ring->blk_ring); |
263 | ring->blk_rings.common.sring = NULL; |
264 | return err; |
265 | } |
266 | |
267 | static int xen_blkif_disconnect(struct xen_blkif *blkif) |
268 | { |
269 | struct pending_req *req, *n; |
270 | unsigned int j, r; |
271 | bool busy = false; |
272 | |
273 | for (r = 0; r < blkif->nr_rings; r++) { |
274 | struct xen_blkif_ring *ring = &blkif->rings[r]; |
275 | unsigned int i = 0; |
276 | |
277 | if (!ring->active) |
278 | continue; |
279 | |
280 | if (ring->xenblkd) { |
281 | kthread_stop(k: ring->xenblkd); |
282 | ring->xenblkd = NULL; |
283 | wake_up(&ring->shutdown_wq); |
284 | } |
285 | |
286 | /* The above kthread_stop() guarantees that at this point we |
287 | * don't have any discard_io or other_io requests. So, checking |
288 | * for inflight IO is enough. |
289 | */ |
290 | if (atomic_read(v: &ring->inflight) > 0) { |
291 | busy = true; |
292 | continue; |
293 | } |
294 | |
295 | if (ring->irq) { |
296 | unbind_from_irqhandler(irq: ring->irq, dev_id: ring); |
297 | ring->irq = 0; |
298 | } |
299 | |
300 | if (ring->blk_rings.common.sring) { |
301 | xenbus_unmap_ring_vfree(dev: blkif->be->dev, vaddr: ring->blk_ring); |
302 | ring->blk_rings.common.sring = NULL; |
303 | } |
304 | |
305 | /* Remove all persistent grants and the cache of ballooned pages. */ |
306 | xen_blkbk_free_caches(ring); |
307 | |
308 | /* Check that there is no request in use */ |
309 | list_for_each_entry_safe(req, n, &ring->pending_free, free_list) { |
310 | list_del(entry: &req->free_list); |
311 | |
312 | for (j = 0; j < MAX_INDIRECT_SEGMENTS; j++) |
313 | kfree(objp: req->segments[j]); |
314 | |
315 | for (j = 0; j < MAX_INDIRECT_PAGES; j++) |
316 | kfree(objp: req->indirect_pages[j]); |
317 | |
318 | kfree(objp: req); |
319 | i++; |
320 | } |
321 | |
322 | BUG_ON(atomic_read(&ring->persistent_gnt_in_use) != 0); |
323 | BUG_ON(!list_empty(&ring->persistent_purge_list)); |
324 | BUG_ON(!RB_EMPTY_ROOT(&ring->persistent_gnts)); |
325 | BUG_ON(ring->free_pages.num_pages != 0); |
326 | BUG_ON(ring->persistent_gnt_c != 0); |
327 | WARN_ON(i != (XEN_BLKIF_REQS_PER_PAGE * blkif->nr_ring_pages)); |
328 | ring->active = false; |
329 | } |
330 | if (busy) |
331 | return -EBUSY; |
332 | |
333 | blkif->nr_ring_pages = 0; |
334 | /* |
335 | * blkif->rings was allocated in connect_ring, so we should free it in |
336 | * here. |
337 | */ |
338 | kfree(objp: blkif->rings); |
339 | blkif->rings = NULL; |
340 | blkif->nr_rings = 0; |
341 | |
342 | return 0; |
343 | } |
344 | |
345 | static void xen_blkif_free(struct xen_blkif *blkif) |
346 | { |
347 | WARN_ON(xen_blkif_disconnect(blkif)); |
348 | xen_vbd_free(vbd: &blkif->vbd); |
349 | kfree(objp: blkif->be->mode); |
350 | kfree(objp: blkif->be); |
351 | |
352 | /* Make sure everything is drained before shutting down */ |
353 | kmem_cache_free(s: xen_blkif_cachep, objp: blkif); |
354 | module_put(THIS_MODULE); |
355 | } |
356 | |
357 | int __init xen_blkif_interface_init(void) |
358 | { |
359 | xen_blkif_cachep = kmem_cache_create(name: "blkif_cache" , |
360 | size: sizeof(struct xen_blkif), |
361 | align: 0, flags: 0, NULL); |
362 | if (!xen_blkif_cachep) |
363 | return -ENOMEM; |
364 | |
365 | return 0; |
366 | } |
367 | |
368 | void xen_blkif_interface_fini(void) |
369 | { |
370 | kmem_cache_destroy(s: xen_blkif_cachep); |
371 | xen_blkif_cachep = NULL; |
372 | } |
373 | |
374 | /* |
375 | * sysfs interface for VBD I/O requests |
376 | */ |
377 | |
378 | #define VBD_SHOW_ALLRING(name, format) \ |
379 | static ssize_t show_##name(struct device *_dev, \ |
380 | struct device_attribute *attr, \ |
381 | char *buf) \ |
382 | { \ |
383 | struct xenbus_device *dev = to_xenbus_device(_dev); \ |
384 | struct backend_info *be = dev_get_drvdata(&dev->dev); \ |
385 | struct xen_blkif *blkif = be->blkif; \ |
386 | unsigned int i; \ |
387 | unsigned long long result = 0; \ |
388 | \ |
389 | if (!blkif->rings) \ |
390 | goto out; \ |
391 | \ |
392 | for (i = 0; i < blkif->nr_rings; i++) { \ |
393 | struct xen_blkif_ring *ring = &blkif->rings[i]; \ |
394 | \ |
395 | result += ring->st_##name; \ |
396 | } \ |
397 | \ |
398 | out: \ |
399 | return sprintf(buf, format, result); \ |
400 | } \ |
401 | static DEVICE_ATTR(name, 0444, show_##name, NULL) |
402 | |
403 | VBD_SHOW_ALLRING(oo_req, "%llu\n" ); |
404 | VBD_SHOW_ALLRING(rd_req, "%llu\n" ); |
405 | VBD_SHOW_ALLRING(wr_req, "%llu\n" ); |
406 | VBD_SHOW_ALLRING(f_req, "%llu\n" ); |
407 | VBD_SHOW_ALLRING(ds_req, "%llu\n" ); |
408 | VBD_SHOW_ALLRING(rd_sect, "%llu\n" ); |
409 | VBD_SHOW_ALLRING(wr_sect, "%llu\n" ); |
410 | |
411 | static struct attribute *xen_vbdstat_attrs[] = { |
412 | &dev_attr_oo_req.attr, |
413 | &dev_attr_rd_req.attr, |
414 | &dev_attr_wr_req.attr, |
415 | &dev_attr_f_req.attr, |
416 | &dev_attr_ds_req.attr, |
417 | &dev_attr_rd_sect.attr, |
418 | &dev_attr_wr_sect.attr, |
419 | NULL |
420 | }; |
421 | |
422 | static const struct attribute_group xen_vbdstat_group = { |
423 | .name = "statistics" , |
424 | .attrs = xen_vbdstat_attrs, |
425 | }; |
426 | |
427 | #define VBD_SHOW(name, format, args...) \ |
428 | static ssize_t show_##name(struct device *_dev, \ |
429 | struct device_attribute *attr, \ |
430 | char *buf) \ |
431 | { \ |
432 | struct xenbus_device *dev = to_xenbus_device(_dev); \ |
433 | struct backend_info *be = dev_get_drvdata(&dev->dev); \ |
434 | \ |
435 | return sprintf(buf, format, ##args); \ |
436 | } \ |
437 | static DEVICE_ATTR(name, 0444, show_##name, NULL) |
438 | |
439 | VBD_SHOW(physical_device, "%x:%x\n" , be->major, be->minor); |
440 | VBD_SHOW(mode, "%s\n" , be->mode); |
441 | |
442 | static int xenvbd_sysfs_addif(struct xenbus_device *dev) |
443 | { |
444 | int error; |
445 | |
446 | error = device_create_file(device: &dev->dev, entry: &dev_attr_physical_device); |
447 | if (error) |
448 | goto fail1; |
449 | |
450 | error = device_create_file(device: &dev->dev, entry: &dev_attr_mode); |
451 | if (error) |
452 | goto fail2; |
453 | |
454 | error = sysfs_create_group(kobj: &dev->dev.kobj, grp: &xen_vbdstat_group); |
455 | if (error) |
456 | goto fail3; |
457 | |
458 | return 0; |
459 | |
460 | fail3: sysfs_remove_group(kobj: &dev->dev.kobj, grp: &xen_vbdstat_group); |
461 | fail2: device_remove_file(dev: &dev->dev, attr: &dev_attr_mode); |
462 | fail1: device_remove_file(dev: &dev->dev, attr: &dev_attr_physical_device); |
463 | return error; |
464 | } |
465 | |
466 | static void xenvbd_sysfs_delif(struct xenbus_device *dev) |
467 | { |
468 | sysfs_remove_group(kobj: &dev->dev.kobj, grp: &xen_vbdstat_group); |
469 | device_remove_file(dev: &dev->dev, attr: &dev_attr_mode); |
470 | device_remove_file(dev: &dev->dev, attr: &dev_attr_physical_device); |
471 | } |
472 | |
473 | static void xen_vbd_free(struct xen_vbd *vbd) |
474 | { |
475 | if (vbd->bdev_file) |
476 | fput(vbd->bdev_file); |
477 | vbd->bdev_file = NULL; |
478 | } |
479 | |
480 | static int xen_vbd_create(struct xen_blkif *blkif, blkif_vdev_t handle, |
481 | unsigned major, unsigned minor, int readonly, |
482 | int cdrom) |
483 | { |
484 | struct xen_vbd *vbd; |
485 | struct file *bdev_file; |
486 | |
487 | vbd = &blkif->vbd; |
488 | vbd->handle = handle; |
489 | vbd->readonly = readonly; |
490 | vbd->type = 0; |
491 | |
492 | vbd->pdevice = MKDEV(major, minor); |
493 | |
494 | bdev_file = bdev_file_open_by_dev(dev: vbd->pdevice, mode: vbd->readonly ? |
495 | BLK_OPEN_READ : BLK_OPEN_WRITE, NULL, NULL); |
496 | |
497 | if (IS_ERR(ptr: bdev_file)) { |
498 | pr_warn("xen_vbd_create: device %08x could not be opened\n" , |
499 | vbd->pdevice); |
500 | return -ENOENT; |
501 | } |
502 | |
503 | vbd->bdev_file = bdev_file; |
504 | if (file_bdev(bdev_file: vbd->bdev_file)->bd_disk == NULL) { |
505 | pr_warn("xen_vbd_create: device %08x doesn't exist\n" , |
506 | vbd->pdevice); |
507 | xen_vbd_free(vbd); |
508 | return -ENOENT; |
509 | } |
510 | vbd->size = vbd_sz(vbd); |
511 | |
512 | if (cdrom || disk_to_cdi(file_bdev(vbd->bdev_file)->bd_disk)) |
513 | vbd->type |= VDISK_CDROM; |
514 | if (file_bdev(bdev_file: vbd->bdev_file)->bd_disk->flags & GENHD_FL_REMOVABLE) |
515 | vbd->type |= VDISK_REMOVABLE; |
516 | |
517 | if (bdev_write_cache(bdev: file_bdev(bdev_file))) |
518 | vbd->flush_support = true; |
519 | if (bdev_max_secure_erase_sectors(bdev: file_bdev(bdev_file))) |
520 | vbd->discard_secure = true; |
521 | |
522 | pr_debug("Successful creation of handle=%04x (dom=%u)\n" , |
523 | handle, blkif->domid); |
524 | return 0; |
525 | } |
526 | |
527 | static void xen_blkbk_remove(struct xenbus_device *dev) |
528 | { |
529 | struct backend_info *be = dev_get_drvdata(dev: &dev->dev); |
530 | |
531 | pr_debug("%s %p %d\n" , __func__, dev, dev->otherend_id); |
532 | |
533 | if (be->major || be->minor) |
534 | xenvbd_sysfs_delif(dev); |
535 | |
536 | if (be->backend_watch.node) { |
537 | unregister_xenbus_watch(watch: &be->backend_watch); |
538 | kfree(objp: be->backend_watch.node); |
539 | be->backend_watch.node = NULL; |
540 | } |
541 | |
542 | dev_set_drvdata(dev: &dev->dev, NULL); |
543 | |
544 | if (be->blkif) { |
545 | xen_blkif_disconnect(blkif: be->blkif); |
546 | |
547 | /* Put the reference we set in xen_blkif_alloc(). */ |
548 | xen_blkif_put(be->blkif); |
549 | } |
550 | } |
551 | |
552 | int xen_blkbk_flush_diskcache(struct xenbus_transaction xbt, |
553 | struct backend_info *be, int state) |
554 | { |
555 | struct xenbus_device *dev = be->dev; |
556 | int err; |
557 | |
558 | err = xenbus_printf(t: xbt, dir: dev->nodename, node: "feature-flush-cache" , |
559 | fmt: "%d" , state); |
560 | if (err) |
561 | dev_warn(&dev->dev, "writing feature-flush-cache (%d)" , err); |
562 | |
563 | return err; |
564 | } |
565 | |
566 | static void xen_blkbk_discard(struct xenbus_transaction xbt, struct backend_info *be) |
567 | { |
568 | struct xenbus_device *dev = be->dev; |
569 | struct xen_blkif *blkif = be->blkif; |
570 | int err; |
571 | int state = 0; |
572 | struct block_device *bdev = file_bdev(bdev_file: be->blkif->vbd.bdev_file); |
573 | |
574 | if (!xenbus_read_unsigned(dir: dev->nodename, node: "discard-enable" , default_val: 1)) |
575 | return; |
576 | |
577 | if (bdev_max_discard_sectors(bdev)) { |
578 | err = xenbus_printf(t: xbt, dir: dev->nodename, |
579 | node: "discard-granularity" , fmt: "%u" , |
580 | bdev_discard_granularity(bdev)); |
581 | if (err) { |
582 | dev_warn(&dev->dev, "writing discard-granularity (%d)" , err); |
583 | return; |
584 | } |
585 | err = xenbus_printf(t: xbt, dir: dev->nodename, |
586 | node: "discard-alignment" , fmt: "%u" , |
587 | bdev_discard_alignment(bdev)); |
588 | if (err) { |
589 | dev_warn(&dev->dev, "writing discard-alignment (%d)" , err); |
590 | return; |
591 | } |
592 | state = 1; |
593 | /* Optional. */ |
594 | err = xenbus_printf(t: xbt, dir: dev->nodename, |
595 | node: "discard-secure" , fmt: "%d" , |
596 | blkif->vbd.discard_secure); |
597 | if (err) { |
598 | dev_warn(&dev->dev, "writing discard-secure (%d)" , err); |
599 | return; |
600 | } |
601 | } |
602 | err = xenbus_printf(t: xbt, dir: dev->nodename, node: "feature-discard" , |
603 | fmt: "%d" , state); |
604 | if (err) |
605 | dev_warn(&dev->dev, "writing feature-discard (%d)" , err); |
606 | } |
607 | |
608 | int xen_blkbk_barrier(struct xenbus_transaction xbt, |
609 | struct backend_info *be, int state) |
610 | { |
611 | struct xenbus_device *dev = be->dev; |
612 | int err; |
613 | |
614 | err = xenbus_printf(t: xbt, dir: dev->nodename, node: "feature-barrier" , |
615 | fmt: "%d" , state); |
616 | if (err) |
617 | dev_warn(&dev->dev, "writing feature-barrier (%d)" , err); |
618 | |
619 | return err; |
620 | } |
621 | |
622 | /* |
623 | * Entry point to this code when a new device is created. Allocate the basic |
624 | * structures, and watch the store waiting for the hotplug scripts to tell us |
625 | * the device's physical major and minor numbers. Switch to InitWait. |
626 | */ |
627 | static int xen_blkbk_probe(struct xenbus_device *dev, |
628 | const struct xenbus_device_id *id) |
629 | { |
630 | int err; |
631 | struct backend_info *be = kzalloc(size: sizeof(struct backend_info), |
632 | GFP_KERNEL); |
633 | |
634 | /* match the pr_debug in xen_blkbk_remove */ |
635 | pr_debug("%s %p %d\n" , __func__, dev, dev->otherend_id); |
636 | |
637 | if (!be) { |
638 | xenbus_dev_fatal(dev, err: -ENOMEM, |
639 | fmt: "allocating backend structure" ); |
640 | return -ENOMEM; |
641 | } |
642 | be->dev = dev; |
643 | dev_set_drvdata(dev: &dev->dev, data: be); |
644 | |
645 | be->blkif = xen_blkif_alloc(domid: dev->otherend_id); |
646 | if (IS_ERR(ptr: be->blkif)) { |
647 | err = PTR_ERR(ptr: be->blkif); |
648 | be->blkif = NULL; |
649 | xenbus_dev_fatal(dev, err, fmt: "creating block interface" ); |
650 | goto fail; |
651 | } |
652 | |
653 | err = xenbus_printf(XBT_NIL, dir: dev->nodename, |
654 | node: "feature-max-indirect-segments" , fmt: "%u" , |
655 | MAX_INDIRECT_SEGMENTS); |
656 | if (err) |
657 | dev_warn(&dev->dev, |
658 | "writing %s/feature-max-indirect-segments (%d)" , |
659 | dev->nodename, err); |
660 | |
661 | /* Multi-queue: advertise how many queues are supported by us.*/ |
662 | err = xenbus_printf(XBT_NIL, dev->nodename, |
663 | "multi-queue-max-queues" , "%u" , xenblk_max_queues); |
664 | if (err) |
665 | pr_warn("Error writing multi-queue-max-queues\n" ); |
666 | |
667 | /* setup back pointer */ |
668 | be->blkif->be = be; |
669 | |
670 | err = xenbus_watch_pathfmt(dev, &be->backend_watch, NULL, |
671 | backend_changed, |
672 | "%s/%s" , dev->nodename, "physical-device" ); |
673 | if (err) |
674 | goto fail; |
675 | |
676 | err = xenbus_printf(XBT_NIL, dev->nodename, "max-ring-page-order" , "%u" , |
677 | xen_blkif_max_ring_order); |
678 | if (err) |
679 | pr_warn("%s write out 'max-ring-page-order' failed\n" , __func__); |
680 | |
681 | err = xenbus_switch_state(dev, XenbusStateInitWait); |
682 | if (err) |
683 | goto fail; |
684 | |
685 | return 0; |
686 | |
687 | fail: |
688 | pr_warn("%s failed\n" , __func__); |
689 | xen_blkbk_remove(dev); |
690 | return err; |
691 | } |
692 | |
693 | /* |
694 | * Callback received when the hotplug scripts have placed the physical-device |
695 | * node. Read it and the mode node, and create a vbd. If the frontend is |
696 | * ready, connect. |
697 | */ |
698 | static void backend_changed(struct xenbus_watch *watch, |
699 | const char *path, const char *token) |
700 | { |
701 | int err; |
702 | unsigned major; |
703 | unsigned minor; |
704 | struct backend_info *be |
705 | = container_of(watch, struct backend_info, backend_watch); |
706 | struct xenbus_device *dev = be->dev; |
707 | int cdrom = 0; |
708 | unsigned long handle; |
709 | char *device_type; |
710 | |
711 | pr_debug("%s %p %d\n" , __func__, dev, dev->otherend_id); |
712 | |
713 | err = xenbus_scanf(XBT_NIL, dir: dev->nodename, node: "physical-device" , fmt: "%x:%x" , |
714 | &major, &minor); |
715 | if (XENBUS_EXIST_ERR(err)) { |
716 | /* |
717 | * Since this watch will fire once immediately after it is |
718 | * registered, we expect this. Ignore it, and wait for the |
719 | * hotplug scripts. |
720 | */ |
721 | return; |
722 | } |
723 | if (err != 2) { |
724 | xenbus_dev_fatal(dev, err, "reading physical-device" ); |
725 | return; |
726 | } |
727 | |
728 | if (be->major | be->minor) { |
729 | if (be->major != major || be->minor != minor) |
730 | pr_warn("changing physical device (from %x:%x to %x:%x) not supported.\n" , |
731 | be->major, be->minor, major, minor); |
732 | return; |
733 | } |
734 | |
735 | be->mode = xenbus_read(XBT_NIL, dev->nodename, "mode" , NULL); |
736 | if (IS_ERR(be->mode)) { |
737 | err = PTR_ERR(be->mode); |
738 | be->mode = NULL; |
739 | xenbus_dev_fatal(dev, err, "reading mode" ); |
740 | return; |
741 | } |
742 | |
743 | device_type = xenbus_read(XBT_NIL, dev->otherend, "device-type" , NULL); |
744 | if (!IS_ERR(device_type)) { |
745 | cdrom = strcmp(device_type, "cdrom" ) == 0; |
746 | kfree(device_type); |
747 | } |
748 | |
749 | /* Front end dir is a number, which is used as the handle. */ |
750 | err = kstrtoul(strrchr(dev->otherend, '/') + 1, 0, &handle); |
751 | if (err) { |
752 | kfree(be->mode); |
753 | be->mode = NULL; |
754 | return; |
755 | } |
756 | |
757 | be->major = major; |
758 | be->minor = minor; |
759 | |
760 | err = xen_vbd_create(be->blkif, handle, major, minor, |
761 | !strchr(be->mode, 'w'), cdrom); |
762 | |
763 | if (err) |
764 | xenbus_dev_fatal(dev, err, "creating vbd structure" ); |
765 | else { |
766 | err = xenvbd_sysfs_addif(dev); |
767 | if (err) { |
768 | xen_vbd_free(&be->blkif->vbd); |
769 | xenbus_dev_fatal(dev, err, "creating sysfs entries" ); |
770 | } |
771 | } |
772 | |
773 | if (err) { |
774 | kfree(be->mode); |
775 | be->mode = NULL; |
776 | be->major = 0; |
777 | be->minor = 0; |
778 | } else { |
779 | /* We're potentially connected now */ |
780 | xen_update_blkif_status(be->blkif); |
781 | } |
782 | } |
783 | |
784 | /* |
785 | * Callback received when the frontend's state changes. |
786 | */ |
787 | static void frontend_changed(struct xenbus_device *dev, |
788 | enum xenbus_state frontend_state) |
789 | { |
790 | struct backend_info *be = dev_get_drvdata(dev: &dev->dev); |
791 | int err; |
792 | |
793 | pr_debug("%s %p %s\n" , __func__, dev, xenbus_strstate(frontend_state)); |
794 | |
795 | switch (frontend_state) { |
796 | case XenbusStateInitialising: |
797 | if (dev->state == XenbusStateClosed) { |
798 | pr_info("%s: prepare for reconnect\n" , dev->nodename); |
799 | xenbus_switch_state(dev, new_state: XenbusStateInitWait); |
800 | } |
801 | break; |
802 | |
803 | case XenbusStateInitialised: |
804 | case XenbusStateConnected: |
805 | /* |
806 | * Ensure we connect even when two watches fire in |
807 | * close succession and we miss the intermediate value |
808 | * of frontend_state. |
809 | */ |
810 | if (dev->state == XenbusStateConnected) |
811 | break; |
812 | |
813 | /* |
814 | * Enforce precondition before potential leak point. |
815 | * xen_blkif_disconnect() is idempotent. |
816 | */ |
817 | err = xen_blkif_disconnect(blkif: be->blkif); |
818 | if (err) { |
819 | xenbus_dev_fatal(dev, err, fmt: "pending I/O" ); |
820 | break; |
821 | } |
822 | |
823 | err = connect_ring(be); |
824 | if (err) { |
825 | /* |
826 | * Clean up so that memory resources can be used by |
827 | * other devices. connect_ring reported already error. |
828 | */ |
829 | xen_blkif_disconnect(blkif: be->blkif); |
830 | break; |
831 | } |
832 | xen_update_blkif_status(blkif: be->blkif); |
833 | break; |
834 | |
835 | case XenbusStateClosing: |
836 | xenbus_switch_state(dev, new_state: XenbusStateClosing); |
837 | break; |
838 | |
839 | case XenbusStateClosed: |
840 | xen_blkif_disconnect(blkif: be->blkif); |
841 | xenbus_switch_state(dev, new_state: XenbusStateClosed); |
842 | if (xenbus_dev_is_online(dev)) |
843 | break; |
844 | fallthrough; |
845 | /* if not online */ |
846 | case XenbusStateUnknown: |
847 | /* implies xen_blkif_disconnect() via xen_blkbk_remove() */ |
848 | device_unregister(dev: &dev->dev); |
849 | break; |
850 | |
851 | default: |
852 | xenbus_dev_fatal(dev, err: -EINVAL, fmt: "saw state %d at frontend" , |
853 | frontend_state); |
854 | break; |
855 | } |
856 | } |
857 | |
858 | /* Once a memory pressure is detected, squeeze free page pools for a while. */ |
859 | static unsigned int buffer_squeeze_duration_ms = 10; |
860 | module_param_named(buffer_squeeze_duration_ms, |
861 | buffer_squeeze_duration_ms, int, 0644); |
862 | MODULE_PARM_DESC(buffer_squeeze_duration_ms, |
863 | "Duration in ms to squeeze pages buffer when a memory pressure is detected" ); |
864 | |
865 | /* |
866 | * Callback received when the memory pressure is detected. |
867 | */ |
868 | static void reclaim_memory(struct xenbus_device *dev) |
869 | { |
870 | struct backend_info *be = dev_get_drvdata(dev: &dev->dev); |
871 | |
872 | if (!be) |
873 | return; |
874 | be->blkif->buffer_squeeze_end = jiffies + |
875 | msecs_to_jiffies(m: buffer_squeeze_duration_ms); |
876 | } |
877 | |
878 | /* ** Connection ** */ |
879 | |
880 | /* |
881 | * Write the physical details regarding the block device to the store, and |
882 | * switch to Connected state. |
883 | */ |
884 | static void connect(struct backend_info *be) |
885 | { |
886 | struct xenbus_transaction xbt; |
887 | int err; |
888 | struct xenbus_device *dev = be->dev; |
889 | |
890 | pr_debug("%s %s\n" , __func__, dev->otherend); |
891 | |
892 | /* Supply the information about the device the frontend needs */ |
893 | again: |
894 | err = xenbus_transaction_start(t: &xbt); |
895 | if (err) { |
896 | xenbus_dev_fatal(dev, err, fmt: "starting transaction" ); |
897 | return; |
898 | } |
899 | |
900 | /* If we can't advertise it is OK. */ |
901 | xen_blkbk_flush_diskcache(xbt, be, state: be->blkif->vbd.flush_support); |
902 | |
903 | xen_blkbk_discard(xbt, be); |
904 | |
905 | xen_blkbk_barrier(xbt, be, state: be->blkif->vbd.flush_support); |
906 | |
907 | err = xenbus_printf(t: xbt, dir: dev->nodename, node: "feature-persistent" , fmt: "%u" , |
908 | be->blkif->vbd.feature_gnt_persistent_parm); |
909 | if (err) { |
910 | xenbus_dev_fatal(dev, err, fmt: "writing %s/feature-persistent" , |
911 | dev->nodename); |
912 | goto abort; |
913 | } |
914 | |
915 | err = xenbus_printf(t: xbt, dir: dev->nodename, node: "sectors" , fmt: "%llu" , |
916 | (unsigned long long)vbd_sz(&be->blkif->vbd)); |
917 | if (err) { |
918 | xenbus_dev_fatal(dev, err, fmt: "writing %s/sectors" , |
919 | dev->nodename); |
920 | goto abort; |
921 | } |
922 | |
923 | /* FIXME: use a typename instead */ |
924 | err = xenbus_printf(t: xbt, dir: dev->nodename, node: "info" , fmt: "%u" , |
925 | be->blkif->vbd.type | |
926 | (be->blkif->vbd.readonly ? VDISK_READONLY : 0)); |
927 | if (err) { |
928 | xenbus_dev_fatal(dev, err, fmt: "writing %s/info" , |
929 | dev->nodename); |
930 | goto abort; |
931 | } |
932 | err = xenbus_printf(t: xbt, dir: dev->nodename, node: "sector-size" , fmt: "%lu" , |
933 | (unsigned long)bdev_logical_block_size( |
934 | bdev: file_bdev(bdev_file: be->blkif->vbd.bdev_file))); |
935 | if (err) { |
936 | xenbus_dev_fatal(dev, err, fmt: "writing %s/sector-size" , |
937 | dev->nodename); |
938 | goto abort; |
939 | } |
940 | err = xenbus_printf(t: xbt, dir: dev->nodename, node: "physical-sector-size" , fmt: "%u" , |
941 | bdev_physical_block_size( |
942 | bdev: file_bdev(bdev_file: be->blkif->vbd.bdev_file))); |
943 | if (err) |
944 | xenbus_dev_error(dev, err, fmt: "writing %s/physical-sector-size" , |
945 | dev->nodename); |
946 | |
947 | err = xenbus_transaction_end(t: xbt, abort: 0); |
948 | if (err == -EAGAIN) |
949 | goto again; |
950 | if (err) |
951 | xenbus_dev_fatal(dev, err, fmt: "ending transaction" ); |
952 | |
953 | err = xenbus_switch_state(dev, new_state: XenbusStateConnected); |
954 | if (err) |
955 | xenbus_dev_fatal(dev, err, fmt: "%s: switching to Connected state" , |
956 | dev->nodename); |
957 | |
958 | return; |
959 | abort: |
960 | xenbus_transaction_end(t: xbt, abort: 1); |
961 | } |
962 | |
963 | /* |
964 | * Each ring may have multi pages, depends on "ring-page-order". |
965 | */ |
966 | static int read_per_ring_refs(struct xen_blkif_ring *ring, const char *dir) |
967 | { |
968 | unsigned int ring_ref[XENBUS_MAX_RING_GRANTS]; |
969 | struct pending_req *req, *n; |
970 | int err, i, j; |
971 | struct xen_blkif *blkif = ring->blkif; |
972 | struct xenbus_device *dev = blkif->be->dev; |
973 | unsigned int nr_grefs, evtchn; |
974 | |
975 | err = xenbus_scanf(XBT_NIL, dir, node: "event-channel" , fmt: "%u" , |
976 | &evtchn); |
977 | if (err != 1) { |
978 | err = -EINVAL; |
979 | xenbus_dev_fatal(dev, err, "reading %s/event-channel" , dir); |
980 | return err; |
981 | } |
982 | |
983 | nr_grefs = blkif->nr_ring_pages; |
984 | |
985 | if (unlikely(!nr_grefs)) { |
986 | WARN_ON(true); |
987 | return -EINVAL; |
988 | } |
989 | |
990 | for (i = 0; i < nr_grefs; i++) { |
991 | char ring_ref_name[RINGREF_NAME_LEN]; |
992 | |
993 | if (blkif->multi_ref) |
994 | snprintf(ring_ref_name, RINGREF_NAME_LEN, "ring-ref%u" , i); |
995 | else { |
996 | WARN_ON(i != 0); |
997 | snprintf(ring_ref_name, RINGREF_NAME_LEN, "ring-ref" ); |
998 | } |
999 | |
1000 | err = xenbus_scanf(XBT_NIL, dir, ring_ref_name, |
1001 | "%u" , &ring_ref[i]); |
1002 | |
1003 | if (err != 1) { |
1004 | err = -EINVAL; |
1005 | xenbus_dev_fatal(dev, err, "reading %s/%s" , |
1006 | dir, ring_ref_name); |
1007 | return err; |
1008 | } |
1009 | } |
1010 | |
1011 | err = -ENOMEM; |
1012 | for (i = 0; i < nr_grefs * XEN_BLKIF_REQS_PER_PAGE; i++) { |
1013 | req = kzalloc(sizeof(*req), GFP_KERNEL); |
1014 | if (!req) |
1015 | goto fail; |
1016 | list_add_tail(&req->free_list, &ring->pending_free); |
1017 | for (j = 0; j < MAX_INDIRECT_SEGMENTS; j++) { |
1018 | req->segments[j] = kzalloc(sizeof(*req->segments[0]), GFP_KERNEL); |
1019 | if (!req->segments[j]) |
1020 | goto fail; |
1021 | } |
1022 | for (j = 0; j < MAX_INDIRECT_PAGES; j++) { |
1023 | req->indirect_pages[j] = kzalloc(sizeof(*req->indirect_pages[0]), |
1024 | GFP_KERNEL); |
1025 | if (!req->indirect_pages[j]) |
1026 | goto fail; |
1027 | } |
1028 | } |
1029 | |
1030 | /* Map the shared frame, irq etc. */ |
1031 | err = xen_blkif_map(ring, ring_ref, nr_grefs, evtchn); |
1032 | if (err) { |
1033 | xenbus_dev_fatal(dev, err, "mapping ring-ref port %u" , evtchn); |
1034 | goto fail; |
1035 | } |
1036 | |
1037 | return 0; |
1038 | |
1039 | fail: |
1040 | list_for_each_entry_safe(req, n, &ring->pending_free, free_list) { |
1041 | list_del(&req->free_list); |
1042 | for (j = 0; j < MAX_INDIRECT_SEGMENTS; j++) { |
1043 | if (!req->segments[j]) |
1044 | break; |
1045 | kfree(req->segments[j]); |
1046 | } |
1047 | for (j = 0; j < MAX_INDIRECT_PAGES; j++) { |
1048 | if (!req->indirect_pages[j]) |
1049 | break; |
1050 | kfree(req->indirect_pages[j]); |
1051 | } |
1052 | kfree(req); |
1053 | } |
1054 | return err; |
1055 | } |
1056 | |
1057 | static int connect_ring(struct backend_info *be) |
1058 | { |
1059 | struct xenbus_device *dev = be->dev; |
1060 | struct xen_blkif *blkif = be->blkif; |
1061 | char protocol[64] = "" ; |
1062 | int err, i; |
1063 | char *xspath; |
1064 | size_t xspathsize; |
1065 | const size_t xenstore_path_ext_size = 11; /* sufficient for "/queue-NNN" */ |
1066 | unsigned int requested_num_queues = 0; |
1067 | unsigned int ring_page_order; |
1068 | |
1069 | pr_debug("%s %s\n" , __func__, dev->otherend); |
1070 | |
1071 | blkif->blk_protocol = BLKIF_PROTOCOL_DEFAULT; |
1072 | err = xenbus_scanf(XBT_NIL, dir: dev->otherend, node: "protocol" , |
1073 | fmt: "%63s" , protocol); |
1074 | if (err <= 0) |
1075 | strcpy(protocol, "unspecified, assuming default" ); |
1076 | else if (0 == strcmp(protocol, XEN_IO_PROTO_ABI_NATIVE)) |
1077 | blkif->blk_protocol = BLKIF_PROTOCOL_NATIVE; |
1078 | else if (0 == strcmp(protocol, XEN_IO_PROTO_ABI_X86_32)) |
1079 | blkif->blk_protocol = BLKIF_PROTOCOL_X86_32; |
1080 | else if (0 == strcmp(protocol, XEN_IO_PROTO_ABI_X86_64)) |
1081 | blkif->blk_protocol = BLKIF_PROTOCOL_X86_64; |
1082 | else { |
1083 | xenbus_dev_fatal(dev, err, "unknown fe protocol %s" , protocol); |
1084 | return -ENOSYS; |
1085 | } |
1086 | |
1087 | blkif->vbd.feature_gnt_persistent_parm = feature_persistent; |
1088 | blkif->vbd.feature_gnt_persistent = |
1089 | blkif->vbd.feature_gnt_persistent_parm && |
1090 | xenbus_read_unsigned(dev->otherend, "feature-persistent" , 0); |
1091 | |
1092 | blkif->vbd.overflow_max_grants = 0; |
1093 | |
1094 | /* |
1095 | * Read the number of hardware queues from frontend. |
1096 | */ |
1097 | requested_num_queues = xenbus_read_unsigned(dev->otherend, |
1098 | "multi-queue-num-queues" , |
1099 | 1); |
1100 | if (requested_num_queues > xenblk_max_queues |
1101 | || requested_num_queues == 0) { |
1102 | /* Buggy or malicious guest. */ |
1103 | xenbus_dev_fatal(dev, err, |
1104 | "guest requested %u queues, exceeding the maximum of %u." , |
1105 | requested_num_queues, xenblk_max_queues); |
1106 | return -ENOSYS; |
1107 | } |
1108 | blkif->nr_rings = requested_num_queues; |
1109 | if (xen_blkif_alloc_rings(blkif)) |
1110 | return -ENOMEM; |
1111 | |
1112 | pr_info("%s: using %d queues, protocol %d (%s) %s\n" , dev->nodename, |
1113 | blkif->nr_rings, blkif->blk_protocol, protocol, |
1114 | blkif->vbd.feature_gnt_persistent ? "persistent grants" : "" ); |
1115 | |
1116 | err = xenbus_scanf(XBT_NIL, dev->otherend, "ring-page-order" , "%u" , |
1117 | &ring_page_order); |
1118 | if (err != 1) { |
1119 | blkif->nr_ring_pages = 1; |
1120 | blkif->multi_ref = false; |
1121 | } else if (ring_page_order <= xen_blkif_max_ring_order) { |
1122 | blkif->nr_ring_pages = 1 << ring_page_order; |
1123 | blkif->multi_ref = true; |
1124 | } else { |
1125 | err = -EINVAL; |
1126 | xenbus_dev_fatal(dev, err, |
1127 | "requested ring page order %d exceed max:%d" , |
1128 | ring_page_order, |
1129 | xen_blkif_max_ring_order); |
1130 | return err; |
1131 | } |
1132 | |
1133 | if (blkif->nr_rings == 1) |
1134 | return read_per_ring_refs(&blkif->rings[0], dev->otherend); |
1135 | else { |
1136 | xspathsize = strlen(dev->otherend) + xenstore_path_ext_size; |
1137 | xspath = kmalloc(xspathsize, GFP_KERNEL); |
1138 | if (!xspath) { |
1139 | xenbus_dev_fatal(dev, -ENOMEM, "reading ring references" ); |
1140 | return -ENOMEM; |
1141 | } |
1142 | |
1143 | for (i = 0; i < blkif->nr_rings; i++) { |
1144 | memset(xspath, 0, xspathsize); |
1145 | snprintf(xspath, xspathsize, "%s/queue-%u" , dev->otherend, i); |
1146 | err = read_per_ring_refs(&blkif->rings[i], xspath); |
1147 | if (err) { |
1148 | kfree(xspath); |
1149 | return err; |
1150 | } |
1151 | } |
1152 | kfree(xspath); |
1153 | } |
1154 | return 0; |
1155 | } |
1156 | |
1157 | static const struct xenbus_device_id xen_blkbk_ids[] = { |
1158 | { "vbd" }, |
1159 | { "" } |
1160 | }; |
1161 | |
1162 | static struct xenbus_driver xen_blkbk_driver = { |
1163 | .ids = xen_blkbk_ids, |
1164 | .probe = xen_blkbk_probe, |
1165 | .remove = xen_blkbk_remove, |
1166 | .otherend_changed = frontend_changed, |
1167 | .allow_rebind = true, |
1168 | .reclaim_memory = reclaim_memory, |
1169 | }; |
1170 | |
1171 | int xen_blkif_xenbus_init(void) |
1172 | { |
1173 | return xenbus_register_backend(&xen_blkbk_driver); |
1174 | } |
1175 | |
1176 | void xen_blkif_xenbus_fini(void) |
1177 | { |
1178 | xenbus_unregister_driver(drv: &xen_blkbk_driver); |
1179 | } |
1180 | |