Commit | Line | Data |
---|---|---|
4d05a28d KRW |
1 | /* Xenbus code for blkif backend |
2 | Copyright (C) 2005 Rusty Russell <rusty@rustcorp.com.au> | |
3 | Copyright (C) 2005 XenSource Ltd | |
4 | ||
5 | This program is free software; you can redistribute it and/or modify | |
6 | it under the terms of the GNU General Public License as published by | |
7 | the Free Software Foundation; either version 2 of the License, or | |
8 | (at your option) any later version. | |
9 | ||
10 | This program is distributed in the hope that it will be useful, | |
11 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
13 | GNU General Public License for more details. | |
14 | ||
4d05a28d KRW |
15 | */ |
16 | ||
77387b82 TC |
17 | #define pr_fmt(fmt) "xen-blkback: " fmt |
18 | ||
4d05a28d KRW |
19 | #include <stdarg.h> |
20 | #include <linux/module.h> | |
21 | #include <linux/kthread.h> | |
ee9ff853 KRW |
22 | #include <xen/events.h> |
23 | #include <xen/grant_table.h> | |
4d05a28d KRW |
24 | #include "common.h" |
25 | ||
1375590d TC |
26 | /* Enlarge the array size in order to fully show blkback name. */ |
27 | #define BLKBACK_NAME_LEN (20) | |
86839c56 | 28 | #define RINGREF_NAME_LEN (20) |
1375590d | 29 | |
d6091b21 | 30 | struct backend_info { |
01f37f2d | 31 | struct xenbus_device *dev; |
51854322 | 32 | struct xen_blkif *blkif; |
01f37f2d KRW |
33 | struct xenbus_watch backend_watch; |
34 | unsigned major; | |
35 | unsigned minor; | |
36 | char *mode; | |
4d05a28d KRW |
37 | }; |
38 | ||
8b6bf747 | 39 | static struct kmem_cache *xen_blkif_cachep; |
4d05a28d KRW |
40 | static void connect(struct backend_info *); |
41 | static int connect_ring(struct backend_info *); | |
42 | static void backend_changed(struct xenbus_watch *, const char **, | |
43 | unsigned int); | |
814d04e7 VP |
44 | static void xen_blkif_free(struct xen_blkif *blkif); |
45 | static void xen_vbd_free(struct xen_vbd *vbd); | |
4d05a28d | 46 | |
8b6bf747 | 47 | struct xenbus_device *xen_blkbk_xenbus(struct backend_info *be) |
98e036a3 JF |
48 | { |
49 | return be->dev; | |
50 | } | |
51 | ||
814d04e7 VP |
52 | /* |
53 | * The last request could free the device from softirq context and | |
54 | * xen_blkif_free() can sleep. | |
55 | */ | |
56 | static void xen_blkif_deferred_free(struct work_struct *work) | |
57 | { | |
58 | struct xen_blkif *blkif; | |
59 | ||
60 | blkif = container_of(work, struct xen_blkif, free_work); | |
61 | xen_blkif_free(blkif); | |
62 | } | |
63 | ||
30fd1502 | 64 | static int blkback_name(struct xen_blkif *blkif, char *buf) |
4d05a28d KRW |
65 | { |
66 | char *devpath, *devname; | |
67 | struct xenbus_device *dev = blkif->be->dev; | |
68 | ||
69 | devpath = xenbus_read(XBT_NIL, dev->nodename, "dev", NULL); | |
70 | if (IS_ERR(devpath)) | |
71 | return PTR_ERR(devpath); | |
72 | ||
d6091b21 KRW |
73 | devname = strstr(devpath, "/dev/"); |
74 | if (devname != NULL) | |
4d05a28d KRW |
75 | devname += strlen("/dev/"); |
76 | else | |
77 | devname = devpath; | |
78 | ||
1375590d | 79 | snprintf(buf, BLKBACK_NAME_LEN, "blkback.%d.%s", blkif->domid, devname); |
4d05a28d KRW |
80 | kfree(devpath); |
81 | ||
82 | return 0; | |
83 | } | |
84 | ||
30fd1502 | 85 | static void xen_update_blkif_status(struct xen_blkif *blkif) |
4d05a28d KRW |
86 | { |
87 | int err; | |
1375590d | 88 | char name[BLKBACK_NAME_LEN]; |
4d05a28d KRW |
89 | |
90 | /* Not ready to connect? */ | |
91 | if (!blkif->irq || !blkif->vbd.bdev) | |
92 | return; | |
93 | ||
94 | /* Already connected? */ | |
95 | if (blkif->be->dev->state == XenbusStateConnected) | |
96 | return; | |
97 | ||
98 | /* Attempt to connect: exit if we fail to. */ | |
99 | connect(blkif->be); | |
100 | if (blkif->be->dev->state != XenbusStateConnected) | |
101 | return; | |
102 | ||
103 | err = blkback_name(blkif, name); | |
104 | if (err) { | |
105 | xenbus_dev_error(blkif->be->dev, err, "get blkback dev name"); | |
106 | return; | |
107 | } | |
108 | ||
cbf46290 CL |
109 | err = filemap_write_and_wait(blkif->vbd.bdev->bd_inode->i_mapping); |
110 | if (err) { | |
111 | xenbus_dev_error(blkif->be->dev, err, "block flush"); | |
112 | return; | |
113 | } | |
114 | invalidate_inode_pages2(blkif->vbd.bdev->bd_inode->i_mapping); | |
115 | ||
f170168b | 116 | blkif->xenblkd = kthread_run(xen_blkif_schedule, blkif, "%s", name); |
4d05a28d KRW |
117 | if (IS_ERR(blkif->xenblkd)) { |
118 | err = PTR_ERR(blkif->xenblkd); | |
119 | blkif->xenblkd = NULL; | |
120 | xenbus_dev_error(blkif->be->dev, err, "start xenblkd"); | |
3f3aad5e | 121 | return; |
4d05a28d KRW |
122 | } |
123 | } | |
124 | ||
30fd1502 | 125 | static struct xen_blkif *xen_blkif_alloc(domid_t domid) |
ee9ff853 | 126 | { |
30fd1502 | 127 | struct xen_blkif *blkif; |
ee9ff853 | 128 | |
402b27f9 | 129 | BUILD_BUG_ON(MAX_INDIRECT_PAGES > BLKIF_MAX_INDIRECT_PAGES_PER_REQUEST); |
ee9ff853 | 130 | |
654dbef2 | 131 | blkif = kmem_cache_zalloc(xen_blkif_cachep, GFP_KERNEL); |
ee9ff853 KRW |
132 | if (!blkif) |
133 | return ERR_PTR(-ENOMEM); | |
134 | ||
ee9ff853 KRW |
135 | blkif->domid = domid; |
136 | spin_lock_init(&blkif->blk_ring_lock); | |
137 | atomic_set(&blkif->refcnt, 1); | |
138 | init_waitqueue_head(&blkif->wq); | |
29bde093 KRW |
139 | init_completion(&blkif->drain_complete); |
140 | atomic_set(&blkif->drain, 0); | |
ee9ff853 | 141 | blkif->st_print = jiffies; |
0a8704a5 | 142 | blkif->persistent_gnts.rb_node = NULL; |
c6cc142d RPM |
143 | spin_lock_init(&blkif->free_pages_lock); |
144 | INIT_LIST_HEAD(&blkif->free_pages); | |
ef753411 | 145 | INIT_LIST_HEAD(&blkif->persistent_purge_list); |
c6cc142d | 146 | blkif->free_pages_num = 0; |
3f3aad5e | 147 | atomic_set(&blkif->persistent_gnt_in_use, 0); |
c05f3e3c | 148 | atomic_set(&blkif->inflight, 0); |
abb97b8c | 149 | INIT_WORK(&blkif->persistent_purge_work, xen_blkbk_unmap_purged_grants); |
ee9ff853 | 150 | |
bf0720c4 | 151 | INIT_LIST_HEAD(&blkif->pending_free); |
814d04e7 | 152 | INIT_WORK(&blkif->free_work, xen_blkif_deferred_free); |
bf0720c4 RPM |
153 | spin_lock_init(&blkif->pending_free_lock); |
154 | init_waitqueue_head(&blkif->pending_free_wq); | |
8e3f8755 | 155 | init_waitqueue_head(&blkif->shutdown_wq); |
ee9ff853 KRW |
156 | |
157 | return blkif; | |
158 | } | |
159 | ||
86839c56 BL |
160 | static int xen_blkif_map(struct xen_blkif *blkif, grant_ref_t *gref, |
161 | unsigned int nr_grefs, unsigned int evtchn) | |
ee9ff853 KRW |
162 | { |
163 | int err; | |
164 | ||
165 | /* Already connected through? */ | |
166 | if (blkif->irq) | |
167 | return 0; | |
168 | ||
86839c56 | 169 | err = xenbus_map_ring_valloc(blkif->be->dev, gref, nr_grefs, |
ccc9d90a | 170 | &blkif->blk_ring); |
2d073846 | 171 | if (err < 0) |
ee9ff853 | 172 | return err; |
ee9ff853 KRW |
173 | |
174 | switch (blkif->blk_protocol) { | |
175 | case BLKIF_PROTOCOL_NATIVE: | |
176 | { | |
177 | struct blkif_sring *sring; | |
2d073846 | 178 | sring = (struct blkif_sring *)blkif->blk_ring; |
67de5dfb JG |
179 | BACK_RING_INIT(&blkif->blk_rings.native, sring, |
180 | XEN_PAGE_SIZE * nr_grefs); | |
ee9ff853 KRW |
181 | break; |
182 | } | |
183 | case BLKIF_PROTOCOL_X86_32: | |
184 | { | |
185 | struct blkif_x86_32_sring *sring_x86_32; | |
2d073846 | 186 | sring_x86_32 = (struct blkif_x86_32_sring *)blkif->blk_ring; |
67de5dfb JG |
187 | BACK_RING_INIT(&blkif->blk_rings.x86_32, sring_x86_32, |
188 | XEN_PAGE_SIZE * nr_grefs); | |
ee9ff853 KRW |
189 | break; |
190 | } | |
191 | case BLKIF_PROTOCOL_X86_64: | |
192 | { | |
193 | struct blkif_x86_64_sring *sring_x86_64; | |
2d073846 | 194 | sring_x86_64 = (struct blkif_x86_64_sring *)blkif->blk_ring; |
67de5dfb JG |
195 | BACK_RING_INIT(&blkif->blk_rings.x86_64, sring_x86_64, |
196 | XEN_PAGE_SIZE * nr_grefs); | |
ee9ff853 KRW |
197 | break; |
198 | } | |
199 | default: | |
200 | BUG(); | |
201 | } | |
202 | ||
8b6bf747 KRW |
203 | err = bind_interdomain_evtchn_to_irqhandler(blkif->domid, evtchn, |
204 | xen_blkif_be_int, 0, | |
205 | "blkif-backend", blkif); | |
ee9ff853 | 206 | if (err < 0) { |
2d073846 | 207 | xenbus_unmap_ring_vfree(blkif->be->dev, blkif->blk_ring); |
ee9ff853 KRW |
208 | blkif->blk_rings.common.sring = NULL; |
209 | return err; | |
210 | } | |
211 | blkif->irq = err; | |
212 | ||
213 | return 0; | |
214 | } | |
215 | ||
814d04e7 | 216 | static int xen_blkif_disconnect(struct xen_blkif *blkif) |
ee9ff853 | 217 | { |
f929d42c RPM |
218 | struct pending_req *req, *n; |
219 | int i = 0, j; | |
220 | ||
ee9ff853 KRW |
221 | if (blkif->xenblkd) { |
222 | kthread_stop(blkif->xenblkd); | |
8e3f8755 | 223 | wake_up(&blkif->shutdown_wq); |
ee9ff853 KRW |
224 | blkif->xenblkd = NULL; |
225 | } | |
226 | ||
814d04e7 VP |
227 | /* The above kthread_stop() guarantees that at this point we |
228 | * don't have any discard_io or other_io requests. So, checking | |
229 | * for inflight IO is enough. | |
230 | */ | |
231 | if (atomic_read(&blkif->inflight) > 0) | |
232 | return -EBUSY; | |
ee9ff853 KRW |
233 | |
234 | if (blkif->irq) { | |
235 | unbind_from_irqhandler(blkif->irq, blkif); | |
236 | blkif->irq = 0; | |
237 | } | |
238 | ||
239 | if (blkif->blk_rings.common.sring) { | |
2d073846 | 240 | xenbus_unmap_ring_vfree(blkif->be->dev, blkif->blk_ring); |
ee9ff853 KRW |
241 | blkif->blk_rings.common.sring = NULL; |
242 | } | |
814d04e7 | 243 | |
12ea7296 VK |
244 | /* Remove all persistent grants and the cache of ballooned pages. */ |
245 | xen_blkbk_free_caches(blkif); | |
246 | ||
f929d42c RPM |
247 | /* Check that there is no request in use */ |
248 | list_for_each_entry_safe(req, n, &blkif->pending_free, free_list) { | |
249 | list_del(&req->free_list); | |
250 | ||
251 | for (j = 0; j < MAX_INDIRECT_SEGMENTS; j++) | |
252 | kfree(req->segments[j]); | |
253 | ||
254 | for (j = 0; j < MAX_INDIRECT_PAGES; j++) | |
255 | kfree(req->indirect_pages[j]); | |
256 | ||
257 | kfree(req); | |
258 | i++; | |
259 | } | |
260 | ||
261 | WARN_ON(i != (XEN_BLKIF_REQS_PER_PAGE * blkif->nr_ring_pages)); | |
262 | blkif->nr_ring_pages = 0; | |
263 | ||
814d04e7 | 264 | return 0; |
ee9ff853 KRW |
265 | } |
266 | ||
2911758f | 267 | static void xen_blkif_free(struct xen_blkif *blkif) |
ee9ff853 | 268 | { |
bf0720c4 | 269 | |
814d04e7 VP |
270 | xen_blkif_disconnect(blkif); |
271 | xen_vbd_free(&blkif->vbd); | |
bf0720c4 | 272 | |
ef753411 RPM |
273 | /* Make sure everything is drained before shutting down */ |
274 | BUG_ON(blkif->persistent_gnt_c != 0); | |
275 | BUG_ON(atomic_read(&blkif->persistent_gnt_in_use) != 0); | |
276 | BUG_ON(blkif->free_pages_num != 0); | |
277 | BUG_ON(!list_empty(&blkif->persistent_purge_list)); | |
278 | BUG_ON(!list_empty(&blkif->free_pages)); | |
279 | BUG_ON(!RB_EMPTY_ROOT(&blkif->persistent_gnts)); | |
280 | ||
8b6bf747 | 281 | kmem_cache_free(xen_blkif_cachep, blkif); |
ee9ff853 KRW |
282 | } |
283 | ||
8b6bf747 | 284 | int __init xen_blkif_interface_init(void) |
ee9ff853 | 285 | { |
8b6bf747 | 286 | xen_blkif_cachep = kmem_cache_create("blkif_cache", |
30fd1502 | 287 | sizeof(struct xen_blkif), |
8b6bf747 KRW |
288 | 0, 0, NULL); |
289 | if (!xen_blkif_cachep) | |
ee9ff853 KRW |
290 | return -ENOMEM; |
291 | ||
292 | return 0; | |
293 | } | |
4d05a28d | 294 | |
a1397fa3 | 295 | /* |
4d05a28d KRW |
296 | * sysfs interface for VBD I/O requests |
297 | */ | |
298 | ||
299 | #define VBD_SHOW(name, format, args...) \ | |
300 | static ssize_t show_##name(struct device *_dev, \ | |
301 | struct device_attribute *attr, \ | |
302 | char *buf) \ | |
303 | { \ | |
304 | struct xenbus_device *dev = to_xenbus_device(_dev); \ | |
5cf6e4f6 | 305 | struct backend_info *be = dev_get_drvdata(&dev->dev); \ |
4d05a28d KRW |
306 | \ |
307 | return sprintf(buf, format, ##args); \ | |
308 | } \ | |
309 | static DEVICE_ATTR(name, S_IRUGO, show_##name, NULL) | |
310 | ||
986cacbd ZK |
311 | VBD_SHOW(oo_req, "%llu\n", be->blkif->st_oo_req); |
312 | VBD_SHOW(rd_req, "%llu\n", be->blkif->st_rd_req); | |
313 | VBD_SHOW(wr_req, "%llu\n", be->blkif->st_wr_req); | |
314 | VBD_SHOW(f_req, "%llu\n", be->blkif->st_f_req); | |
315 | VBD_SHOW(ds_req, "%llu\n", be->blkif->st_ds_req); | |
316 | VBD_SHOW(rd_sect, "%llu\n", be->blkif->st_rd_sect); | |
317 | VBD_SHOW(wr_sect, "%llu\n", be->blkif->st_wr_sect); | |
4d05a28d | 318 | |
3d814731 | 319 | static struct attribute *xen_vbdstat_attrs[] = { |
4d05a28d KRW |
320 | &dev_attr_oo_req.attr, |
321 | &dev_attr_rd_req.attr, | |
322 | &dev_attr_wr_req.attr, | |
24f567f9 | 323 | &dev_attr_f_req.attr, |
b3cb0d6a | 324 | &dev_attr_ds_req.attr, |
4d05a28d KRW |
325 | &dev_attr_rd_sect.attr, |
326 | &dev_attr_wr_sect.attr, | |
327 | NULL | |
328 | }; | |
329 | ||
3d814731 | 330 | static struct attribute_group xen_vbdstat_group = { |
4d05a28d | 331 | .name = "statistics", |
3d814731 | 332 | .attrs = xen_vbdstat_attrs, |
4d05a28d KRW |
333 | }; |
334 | ||
335 | VBD_SHOW(physical_device, "%x:%x\n", be->major, be->minor); | |
336 | VBD_SHOW(mode, "%s\n", be->mode); | |
337 | ||
2911758f | 338 | static int xenvbd_sysfs_addif(struct xenbus_device *dev) |
4d05a28d KRW |
339 | { |
340 | int error; | |
341 | ||
342 | error = device_create_file(&dev->dev, &dev_attr_physical_device); | |
d6091b21 | 343 | if (error) |
4d05a28d KRW |
344 | goto fail1; |
345 | ||
346 | error = device_create_file(&dev->dev, &dev_attr_mode); | |
347 | if (error) | |
348 | goto fail2; | |
349 | ||
3d814731 | 350 | error = sysfs_create_group(&dev->dev.kobj, &xen_vbdstat_group); |
4d05a28d KRW |
351 | if (error) |
352 | goto fail3; | |
353 | ||
354 | return 0; | |
355 | ||
3d814731 | 356 | fail3: sysfs_remove_group(&dev->dev.kobj, &xen_vbdstat_group); |
4d05a28d KRW |
357 | fail2: device_remove_file(&dev->dev, &dev_attr_mode); |
358 | fail1: device_remove_file(&dev->dev, &dev_attr_physical_device); | |
359 | return error; | |
360 | } | |
361 | ||
2911758f | 362 | static void xenvbd_sysfs_delif(struct xenbus_device *dev) |
4d05a28d | 363 | { |
3d814731 | 364 | sysfs_remove_group(&dev->dev.kobj, &xen_vbdstat_group); |
4d05a28d KRW |
365 | device_remove_file(&dev->dev, &dev_attr_mode); |
366 | device_remove_file(&dev->dev, &dev_attr_physical_device); | |
367 | } | |
368 | ||
42c7841d | 369 | |
3d814731 | 370 | static void xen_vbd_free(struct xen_vbd *vbd) |
42c7841d KRW |
371 | { |
372 | if (vbd->bdev) | |
373 | blkdev_put(vbd->bdev, vbd->readonly ? FMODE_READ : FMODE_WRITE); | |
374 | vbd->bdev = NULL; | |
375 | } | |
376 | ||
3d814731 KRW |
377 | static int xen_vbd_create(struct xen_blkif *blkif, blkif_vdev_t handle, |
378 | unsigned major, unsigned minor, int readonly, | |
379 | int cdrom) | |
42c7841d | 380 | { |
3d814731 | 381 | struct xen_vbd *vbd; |
42c7841d | 382 | struct block_device *bdev; |
24f567f9 | 383 | struct request_queue *q; |
42c7841d KRW |
384 | |
385 | vbd = &blkif->vbd; | |
386 | vbd->handle = handle; | |
387 | vbd->readonly = readonly; | |
388 | vbd->type = 0; | |
389 | ||
390 | vbd->pdevice = MKDEV(major, minor); | |
391 | ||
392 | bdev = blkdev_get_by_dev(vbd->pdevice, vbd->readonly ? | |
393 | FMODE_READ : FMODE_WRITE, NULL); | |
394 | ||
395 | if (IS_ERR(bdev)) { | |
77387b82 | 396 | pr_warn("xen_vbd_create: device %08x could not be opened\n", |
42c7841d KRW |
397 | vbd->pdevice); |
398 | return -ENOENT; | |
399 | } | |
400 | ||
401 | vbd->bdev = bdev; | |
42c7841d | 402 | if (vbd->bdev->bd_disk == NULL) { |
77387b82 | 403 | pr_warn("xen_vbd_create: device %08x doesn't exist\n", |
42c7841d | 404 | vbd->pdevice); |
3d814731 | 405 | xen_vbd_free(vbd); |
42c7841d KRW |
406 | return -ENOENT; |
407 | } | |
6464920a | 408 | vbd->size = vbd_sz(vbd); |
42c7841d KRW |
409 | |
410 | if (vbd->bdev->bd_disk->flags & GENHD_FL_CD || cdrom) | |
411 | vbd->type |= VDISK_CDROM; | |
412 | if (vbd->bdev->bd_disk->flags & GENHD_FL_REMOVABLE) | |
413 | vbd->type |= VDISK_REMOVABLE; | |
414 | ||
24f567f9 KRW |
415 | q = bdev_get_queue(bdev); |
416 | if (q && q->flush_flags) | |
417 | vbd->flush_support = true; | |
418 | ||
5ea42986 KRW |
419 | if (q && blk_queue_secdiscard(q)) |
420 | vbd->discard_secure = true; | |
421 | ||
77387b82 | 422 | pr_debug("Successful creation of handle=%04x (dom=%u)\n", |
42c7841d KRW |
423 | handle, blkif->domid); |
424 | return 0; | |
425 | } | |
8b6bf747 | 426 | static int xen_blkbk_remove(struct xenbus_device *dev) |
4d05a28d | 427 | { |
5cf6e4f6 | 428 | struct backend_info *be = dev_get_drvdata(&dev->dev); |
4d05a28d | 429 | |
77387b82 | 430 | pr_debug("%s %p %d\n", __func__, dev, dev->otherend_id); |
4d05a28d KRW |
431 | |
432 | if (be->major || be->minor) | |
433 | xenvbd_sysfs_delif(dev); | |
434 | ||
435 | if (be->backend_watch.node) { | |
436 | unregister_xenbus_watch(&be->backend_watch); | |
437 | kfree(be->backend_watch.node); | |
438 | be->backend_watch.node = NULL; | |
439 | } | |
440 | ||
814d04e7 VP |
441 | dev_set_drvdata(&dev->dev, NULL); |
442 | ||
4d05a28d | 443 | if (be->blkif) { |
8b6bf747 | 444 | xen_blkif_disconnect(be->blkif); |
814d04e7 | 445 | xen_blkif_put(be->blkif); |
4d05a28d KRW |
446 | } |
447 | ||
9d092603 | 448 | kfree(be->mode); |
4d05a28d | 449 | kfree(be); |
4d05a28d KRW |
450 | return 0; |
451 | } | |
452 | ||
24f567f9 KRW |
453 | int xen_blkbk_flush_diskcache(struct xenbus_transaction xbt, |
454 | struct backend_info *be, int state) | |
4d05a28d KRW |
455 | { |
456 | struct xenbus_device *dev = be->dev; | |
457 | int err; | |
458 | ||
24f567f9 | 459 | err = xenbus_printf(xbt, dev->nodename, "feature-flush-cache", |
4d05a28d KRW |
460 | "%d", state); |
461 | if (err) | |
3389bb8b | 462 | dev_warn(&dev->dev, "writing feature-flush-cache (%d)", err); |
4d05a28d KRW |
463 | |
464 | return err; | |
465 | } | |
466 | ||
3389bb8b | 467 | static void xen_blkbk_discard(struct xenbus_transaction xbt, struct backend_info *be) |
b3cb0d6a LD |
468 | { |
469 | struct xenbus_device *dev = be->dev; | |
470 | struct xen_blkif *blkif = be->blkif; | |
b3cb0d6a | 471 | int err; |
c926b701 | 472 | int state = 0, discard_enable; |
4dae7670 KRW |
473 | struct block_device *bdev = be->blkif->vbd.bdev; |
474 | struct request_queue *q = bdev_get_queue(bdev); | |
475 | ||
c926b701 OH |
476 | err = xenbus_scanf(XBT_NIL, dev->nodename, "discard-enable", "%d", |
477 | &discard_enable); | |
478 | if (err == 1 && !discard_enable) | |
479 | return; | |
480 | ||
4dae7670 KRW |
481 | if (blk_queue_discard(q)) { |
482 | err = xenbus_printf(xbt, dev->nodename, | |
483 | "discard-granularity", "%u", | |
484 | q->limits.discard_granularity); | |
485 | if (err) { | |
3389bb8b KRW |
486 | dev_warn(&dev->dev, "writing discard-granularity (%d)", err); |
487 | return; | |
4dae7670 KRW |
488 | } |
489 | err = xenbus_printf(xbt, dev->nodename, | |
490 | "discard-alignment", "%u", | |
491 | q->limits.discard_alignment); | |
492 | if (err) { | |
3389bb8b KRW |
493 | dev_warn(&dev->dev, "writing discard-alignment (%d)", err); |
494 | return; | |
b3cb0d6a | 495 | } |
4dae7670 KRW |
496 | state = 1; |
497 | /* Optional. */ | |
498 | err = xenbus_printf(xbt, dev->nodename, | |
499 | "discard-secure", "%d", | |
500 | blkif->vbd.discard_secure); | |
501 | if (err) { | |
a71e23d9 | 502 | dev_warn(&dev->dev, "writing discard-secure (%d)", err); |
3389bb8b | 503 | return; |
b3cb0d6a | 504 | } |
b3cb0d6a | 505 | } |
b3cb0d6a LD |
506 | err = xenbus_printf(xbt, dev->nodename, "feature-discard", |
507 | "%d", state); | |
508 | if (err) | |
3389bb8b | 509 | dev_warn(&dev->dev, "writing feature-discard (%d)", err); |
b3cb0d6a | 510 | } |
29bde093 KRW |
511 | int xen_blkbk_barrier(struct xenbus_transaction xbt, |
512 | struct backend_info *be, int state) | |
513 | { | |
514 | struct xenbus_device *dev = be->dev; | |
515 | int err; | |
516 | ||
517 | err = xenbus_printf(xbt, dev->nodename, "feature-barrier", | |
518 | "%d", state); | |
519 | if (err) | |
3389bb8b | 520 | dev_warn(&dev->dev, "writing feature-barrier (%d)", err); |
29bde093 KRW |
521 | |
522 | return err; | |
523 | } | |
b3cb0d6a | 524 | |
01f37f2d | 525 | /* |
4d05a28d KRW |
526 | * Entry point to this code when a new device is created. Allocate the basic |
527 | * structures, and watch the store waiting for the hotplug scripts to tell us | |
528 | * the device's physical major and minor numbers. Switch to InitWait. | |
529 | */ | |
8b6bf747 KRW |
530 | static int xen_blkbk_probe(struct xenbus_device *dev, |
531 | const struct xenbus_device_id *id) | |
4d05a28d KRW |
532 | { |
533 | int err; | |
534 | struct backend_info *be = kzalloc(sizeof(struct backend_info), | |
535 | GFP_KERNEL); | |
77387b82 TC |
536 | |
537 | /* match the pr_debug in xen_blkbk_remove */ | |
538 | pr_debug("%s %p %d\n", __func__, dev, dev->otherend_id); | |
539 | ||
4d05a28d KRW |
540 | if (!be) { |
541 | xenbus_dev_fatal(dev, -ENOMEM, | |
542 | "allocating backend structure"); | |
543 | return -ENOMEM; | |
544 | } | |
545 | be->dev = dev; | |
5cf6e4f6 | 546 | dev_set_drvdata(&dev->dev, be); |
4d05a28d | 547 | |
8b6bf747 | 548 | be->blkif = xen_blkif_alloc(dev->otherend_id); |
4d05a28d KRW |
549 | if (IS_ERR(be->blkif)) { |
550 | err = PTR_ERR(be->blkif); | |
551 | be->blkif = NULL; | |
552 | xenbus_dev_fatal(dev, err, "creating block interface"); | |
553 | goto fail; | |
554 | } | |
555 | ||
556 | /* setup back pointer */ | |
557 | be->blkif->be = be; | |
558 | ||
88122933 JF |
559 | err = xenbus_watch_pathfmt(dev, &be->backend_watch, backend_changed, |
560 | "%s/%s", dev->nodename, "physical-device"); | |
4d05a28d KRW |
561 | if (err) |
562 | goto fail; | |
563 | ||
86839c56 BL |
564 | err = xenbus_printf(XBT_NIL, dev->nodename, "max-ring-page-order", "%u", |
565 | xen_blkif_max_ring_order); | |
566 | if (err) | |
567 | pr_warn("%s write out 'max-ring-page-order' failed\n", __func__); | |
568 | ||
4d05a28d KRW |
569 | err = xenbus_switch_state(dev, XenbusStateInitWait); |
570 | if (err) | |
571 | goto fail; | |
572 | ||
573 | return 0; | |
574 | ||
575 | fail: | |
77387b82 | 576 | pr_warn("%s failed\n", __func__); |
8b6bf747 | 577 | xen_blkbk_remove(dev); |
4d05a28d KRW |
578 | return err; |
579 | } | |
580 | ||
581 | ||
01f37f2d | 582 | /* |
4d05a28d KRW |
583 | * Callback received when the hotplug scripts have placed the physical-device |
584 | * node. Read it and the mode node, and create a vbd. If the frontend is | |
585 | * ready, connect. | |
586 | */ | |
587 | static void backend_changed(struct xenbus_watch *watch, | |
588 | const char **vec, unsigned int len) | |
589 | { | |
590 | int err; | |
591 | unsigned major; | |
592 | unsigned minor; | |
593 | struct backend_info *be | |
594 | = container_of(watch, struct backend_info, backend_watch); | |
595 | struct xenbus_device *dev = be->dev; | |
596 | int cdrom = 0; | |
9d092603 | 597 | unsigned long handle; |
4d05a28d KRW |
598 | char *device_type; |
599 | ||
77387b82 | 600 | pr_debug("%s %p %d\n", __func__, dev, dev->otherend_id); |
4d05a28d KRW |
601 | |
602 | err = xenbus_scanf(XBT_NIL, dev->nodename, "physical-device", "%x:%x", | |
603 | &major, &minor); | |
604 | if (XENBUS_EXIST_ERR(err)) { | |
01f37f2d KRW |
605 | /* |
606 | * Since this watch will fire once immediately after it is | |
607 | * registered, we expect this. Ignore it, and wait for the | |
608 | * hotplug scripts. | |
609 | */ | |
4d05a28d KRW |
610 | return; |
611 | } | |
612 | if (err != 2) { | |
613 | xenbus_dev_fatal(dev, err, "reading physical-device"); | |
614 | return; | |
615 | } | |
616 | ||
9d092603 JB |
617 | if (be->major | be->minor) { |
618 | if (be->major != major || be->minor != minor) | |
77387b82 | 619 | pr_warn("changing physical device (from %x:%x to %x:%x) not supported.\n", |
9d092603 | 620 | be->major, be->minor, major, minor); |
4d05a28d KRW |
621 | return; |
622 | } | |
623 | ||
624 | be->mode = xenbus_read(XBT_NIL, dev->nodename, "mode", NULL); | |
625 | if (IS_ERR(be->mode)) { | |
626 | err = PTR_ERR(be->mode); | |
627 | be->mode = NULL; | |
628 | xenbus_dev_fatal(dev, err, "reading mode"); | |
629 | return; | |
630 | } | |
631 | ||
632 | device_type = xenbus_read(XBT_NIL, dev->otherend, "device-type", NULL); | |
633 | if (!IS_ERR(device_type)) { | |
634 | cdrom = strcmp(device_type, "cdrom") == 0; | |
635 | kfree(device_type); | |
636 | } | |
637 | ||
9d092603 | 638 | /* Front end dir is a number, which is used as the handle. */ |
bb8e0e84 | 639 | err = kstrtoul(strrchr(dev->otherend, '/') + 1, 0, &handle); |
9d092603 JB |
640 | if (err) |
641 | return; | |
4d05a28d | 642 | |
9d092603 JB |
643 | be->major = major; |
644 | be->minor = minor; | |
4d05a28d | 645 | |
9d092603 JB |
646 | err = xen_vbd_create(be->blkif, handle, major, minor, |
647 | !strchr(be->mode, 'w'), cdrom); | |
4d05a28d | 648 | |
9d092603 JB |
649 | if (err) |
650 | xenbus_dev_fatal(dev, err, "creating vbd structure"); | |
651 | else { | |
4d05a28d KRW |
652 | err = xenvbd_sysfs_addif(dev); |
653 | if (err) { | |
3d814731 | 654 | xen_vbd_free(&be->blkif->vbd); |
4d05a28d | 655 | xenbus_dev_fatal(dev, err, "creating sysfs entries"); |
4d05a28d | 656 | } |
9d092603 | 657 | } |
4d05a28d | 658 | |
9d092603 JB |
659 | if (err) { |
660 | kfree(be->mode); | |
661 | be->mode = NULL; | |
662 | be->major = 0; | |
663 | be->minor = 0; | |
664 | } else { | |
4d05a28d | 665 | /* We're potentially connected now */ |
8b6bf747 | 666 | xen_update_blkif_status(be->blkif); |
4d05a28d KRW |
667 | } |
668 | } | |
669 | ||
670 | ||
01f37f2d | 671 | /* |
4d05a28d KRW |
672 | * Callback received when the frontend's state changes. |
673 | */ | |
674 | static void frontend_changed(struct xenbus_device *dev, | |
675 | enum xenbus_state frontend_state) | |
676 | { | |
5cf6e4f6 | 677 | struct backend_info *be = dev_get_drvdata(&dev->dev); |
4d05a28d KRW |
678 | int err; |
679 | ||
77387b82 | 680 | pr_debug("%s %p %s\n", __func__, dev, xenbus_strstate(frontend_state)); |
4d05a28d KRW |
681 | |
682 | switch (frontend_state) { | |
683 | case XenbusStateInitialising: | |
684 | if (dev->state == XenbusStateClosed) { | |
77387b82 | 685 | pr_info("%s: prepare for reconnect\n", dev->nodename); |
4d05a28d KRW |
686 | xenbus_switch_state(dev, XenbusStateInitWait); |
687 | } | |
688 | break; | |
689 | ||
690 | case XenbusStateInitialised: | |
691 | case XenbusStateConnected: | |
01f37f2d KRW |
692 | /* |
693 | * Ensure we connect even when two watches fire in | |
42b2aa86 | 694 | * close succession and we miss the intermediate value |
01f37f2d KRW |
695 | * of frontend_state. |
696 | */ | |
4d05a28d KRW |
697 | if (dev->state == XenbusStateConnected) |
698 | break; | |
699 | ||
01f37f2d KRW |
700 | /* |
701 | * Enforce precondition before potential leak point. | |
1bc05b0a | 702 | * xen_blkif_disconnect() is idempotent. |
313d7b00 | 703 | */ |
814d04e7 VP |
704 | err = xen_blkif_disconnect(be->blkif); |
705 | if (err) { | |
706 | xenbus_dev_fatal(dev, err, "pending I/O"); | |
707 | break; | |
708 | } | |
313d7b00 | 709 | |
4d05a28d KRW |
710 | err = connect_ring(be); |
711 | if (err) | |
712 | break; | |
8b6bf747 | 713 | xen_update_blkif_status(be->blkif); |
4d05a28d KRW |
714 | break; |
715 | ||
716 | case XenbusStateClosing: | |
4d05a28d KRW |
717 | xenbus_switch_state(dev, XenbusStateClosing); |
718 | break; | |
719 | ||
720 | case XenbusStateClosed: | |
6f5986bc | 721 | xen_blkif_disconnect(be->blkif); |
4d05a28d KRW |
722 | xenbus_switch_state(dev, XenbusStateClosed); |
723 | if (xenbus_dev_is_online(dev)) | |
724 | break; | |
725 | /* fall through if not online */ | |
726 | case XenbusStateUnknown: | |
1bc05b0a | 727 | /* implies xen_blkif_disconnect() via xen_blkbk_remove() */ |
4d05a28d KRW |
728 | device_unregister(&dev->dev); |
729 | break; | |
730 | ||
731 | default: | |
732 | xenbus_dev_fatal(dev, -EINVAL, "saw state %d at frontend", | |
733 | frontend_state); | |
734 | break; | |
735 | } | |
736 | } | |
737 | ||
738 | ||
739 | /* ** Connection ** */ | |
740 | ||
741 | ||
01f37f2d | 742 | /* |
4d05a28d KRW |
743 | * Write the physical details regarding the block device to the store, and |
744 | * switch to Connected state. | |
745 | */ | |
746 | static void connect(struct backend_info *be) | |
747 | { | |
748 | struct xenbus_transaction xbt; | |
749 | int err; | |
750 | struct xenbus_device *dev = be->dev; | |
751 | ||
77387b82 | 752 | pr_debug("%s %s\n", __func__, dev->otherend); |
4d05a28d KRW |
753 | |
754 | /* Supply the information about the device the frontend needs */ | |
755 | again: | |
756 | err = xenbus_transaction_start(&xbt); | |
757 | if (err) { | |
758 | xenbus_dev_fatal(dev, err, "starting transaction"); | |
759 | return; | |
760 | } | |
761 | ||
3389bb8b KRW |
762 | /* If we can't advertise it is OK. */ |
763 | xen_blkbk_flush_diskcache(xbt, be, be->blkif->vbd.flush_support); | |
4d05a28d | 764 | |
3389bb8b | 765 | xen_blkbk_discard(xbt, be); |
b3cb0d6a | 766 | |
3389bb8b | 767 | xen_blkbk_barrier(xbt, be, be->blkif->vbd.flush_support); |
29bde093 | 768 | |
0a8704a5 RPM |
769 | err = xenbus_printf(xbt, dev->nodename, "feature-persistent", "%u", 1); |
770 | if (err) { | |
771 | xenbus_dev_fatal(dev, err, "writing %s/feature-persistent", | |
772 | dev->nodename); | |
773 | goto abort; | |
774 | } | |
402b27f9 RPM |
775 | err = xenbus_printf(xbt, dev->nodename, "feature-max-indirect-segments", "%u", |
776 | MAX_INDIRECT_SEGMENTS); | |
777 | if (err) | |
778 | dev_warn(&dev->dev, "writing %s/feature-max-indirect-segments (%d)", | |
779 | dev->nodename, err); | |
0a8704a5 | 780 | |
4d05a28d | 781 | err = xenbus_printf(xbt, dev->nodename, "sectors", "%llu", |
42c7841d | 782 | (unsigned long long)vbd_sz(&be->blkif->vbd)); |
4d05a28d KRW |
783 | if (err) { |
784 | xenbus_dev_fatal(dev, err, "writing %s/sectors", | |
785 | dev->nodename); | |
786 | goto abort; | |
787 | } | |
788 | ||
789 | /* FIXME: use a typename instead */ | |
790 | err = xenbus_printf(xbt, dev->nodename, "info", "%u", | |
42c7841d KRW |
791 | be->blkif->vbd.type | |
792 | (be->blkif->vbd.readonly ? VDISK_READONLY : 0)); | |
4d05a28d KRW |
793 | if (err) { |
794 | xenbus_dev_fatal(dev, err, "writing %s/info", | |
795 | dev->nodename); | |
796 | goto abort; | |
797 | } | |
798 | err = xenbus_printf(xbt, dev->nodename, "sector-size", "%lu", | |
42c7841d KRW |
799 | (unsigned long) |
800 | bdev_logical_block_size(be->blkif->vbd.bdev)); | |
4d05a28d KRW |
801 | if (err) { |
802 | xenbus_dev_fatal(dev, err, "writing %s/sector-size", | |
803 | dev->nodename); | |
804 | goto abort; | |
805 | } | |
7c4d7d71 SB |
806 | err = xenbus_printf(xbt, dev->nodename, "physical-sector-size", "%u", |
807 | bdev_physical_block_size(be->blkif->vbd.bdev)); | |
808 | if (err) | |
809 | xenbus_dev_error(dev, err, "writing %s/physical-sector-size", | |
810 | dev->nodename); | |
4d05a28d KRW |
811 | |
812 | err = xenbus_transaction_end(xbt, 0); | |
813 | if (err == -EAGAIN) | |
814 | goto again; | |
815 | if (err) | |
816 | xenbus_dev_fatal(dev, err, "ending transaction"); | |
817 | ||
818 | err = xenbus_switch_state(dev, XenbusStateConnected); | |
819 | if (err) | |
08b8bfc1 | 820 | xenbus_dev_fatal(dev, err, "%s: switching to Connected state", |
4d05a28d KRW |
821 | dev->nodename); |
822 | ||
823 | return; | |
824 | abort: | |
825 | xenbus_transaction_end(xbt, 1); | |
826 | } | |
827 | ||
828 | ||
829 | static int connect_ring(struct backend_info *be) | |
830 | { | |
831 | struct xenbus_device *dev = be->dev; | |
9cce2914 | 832 | unsigned int ring_ref[XENBUS_MAX_RING_GRANTS]; |
86839c56 | 833 | unsigned int evtchn, nr_grefs, ring_page_order; |
0a8704a5 | 834 | unsigned int pers_grants; |
4d05a28d | 835 | char protocol[64] = ""; |
69b91ede BL |
836 | struct pending_req *req, *n; |
837 | int err, i, j; | |
4d05a28d | 838 | |
77387b82 | 839 | pr_debug("%s %s\n", __func__, dev->otherend); |
4d05a28d | 840 | |
86839c56 BL |
841 | err = xenbus_scanf(XBT_NIL, dev->otherend, "event-channel", "%u", |
842 | &evtchn); | |
843 | if (err != 1) { | |
844 | err = -EINVAL; | |
845 | xenbus_dev_fatal(dev, err, "reading %s/event-channel", | |
4d05a28d KRW |
846 | dev->otherend); |
847 | return err; | |
848 | } | |
86839c56 BL |
849 | pr_info("event-channel %u\n", evtchn); |
850 | ||
851 | err = xenbus_scanf(XBT_NIL, dev->otherend, "ring-page-order", "%u", | |
852 | &ring_page_order); | |
853 | if (err != 1) { | |
854 | err = xenbus_scanf(XBT_NIL, dev->otherend, "ring-ref", | |
855 | "%u", &ring_ref[0]); | |
856 | if (err != 1) { | |
857 | err = -EINVAL; | |
858 | xenbus_dev_fatal(dev, err, "reading %s/ring-ref", | |
859 | dev->otherend); | |
860 | return err; | |
861 | } | |
862 | nr_grefs = 1; | |
863 | pr_info("%s:using single page: ring-ref %d\n", dev->otherend, | |
864 | ring_ref[0]); | |
865 | } else { | |
866 | unsigned int i; | |
867 | ||
868 | if (ring_page_order > xen_blkif_max_ring_order) { | |
869 | err = -EINVAL; | |
870 | xenbus_dev_fatal(dev, err, "%s/request %d ring page order exceed max:%d", | |
871 | dev->otherend, ring_page_order, | |
872 | xen_blkif_max_ring_order); | |
873 | return err; | |
874 | } | |
875 | ||
876 | nr_grefs = 1 << ring_page_order; | |
877 | for (i = 0; i < nr_grefs; i++) { | |
878 | char ring_ref_name[RINGREF_NAME_LEN]; | |
879 | ||
880 | snprintf(ring_ref_name, RINGREF_NAME_LEN, "ring-ref%u", i); | |
881 | err = xenbus_scanf(XBT_NIL, dev->otherend, ring_ref_name, | |
882 | "%u", &ring_ref[i]); | |
883 | if (err != 1) { | |
884 | err = -EINVAL; | |
885 | xenbus_dev_fatal(dev, err, "reading %s/%s", | |
886 | dev->otherend, ring_ref_name); | |
887 | return err; | |
888 | } | |
889 | pr_info("ring-ref%u: %u\n", i, ring_ref[i]); | |
890 | } | |
891 | } | |
4d05a28d | 892 | |
b042a3ca | 893 | be->blkif->blk_protocol = BLKIF_PROTOCOL_DEFAULT; |
4d05a28d KRW |
894 | err = xenbus_gather(XBT_NIL, dev->otherend, "protocol", |
895 | "%63s", protocol, NULL); | |
896 | if (err) | |
b042a3ca | 897 | strcpy(protocol, "unspecified, assuming default"); |
4d05a28d KRW |
898 | else if (0 == strcmp(protocol, XEN_IO_PROTO_ABI_NATIVE)) |
899 | be->blkif->blk_protocol = BLKIF_PROTOCOL_NATIVE; | |
900 | else if (0 == strcmp(protocol, XEN_IO_PROTO_ABI_X86_32)) | |
901 | be->blkif->blk_protocol = BLKIF_PROTOCOL_X86_32; | |
902 | else if (0 == strcmp(protocol, XEN_IO_PROTO_ABI_X86_64)) | |
903 | be->blkif->blk_protocol = BLKIF_PROTOCOL_X86_64; | |
904 | else { | |
905 | xenbus_dev_fatal(dev, err, "unknown fe protocol %s", protocol); | |
906 | return -1; | |
907 | } | |
0a8704a5 | 908 | err = xenbus_gather(XBT_NIL, dev->otherend, |
cb5bd4d1 | 909 | "feature-persistent", "%u", |
0a8704a5 RPM |
910 | &pers_grants, NULL); |
911 | if (err) | |
912 | pers_grants = 0; | |
913 | ||
914 | be->blkif->vbd.feature_gnt_persistent = pers_grants; | |
915 | be->blkif->vbd.overflow_max_grants = 0; | |
86839c56 | 916 | be->blkif->nr_ring_pages = nr_grefs; |
0a8704a5 | 917 | |
86839c56 BL |
918 | pr_info("ring-pages:%d, event-channel %d, protocol %d (%s) %s\n", |
919 | nr_grefs, evtchn, be->blkif->blk_protocol, protocol, | |
0a8704a5 | 920 | pers_grants ? "persistent grants" : ""); |
4d05a28d | 921 | |
86839c56 | 922 | for (i = 0; i < nr_grefs * XEN_BLKIF_REQS_PER_PAGE; i++) { |
69b91ede BL |
923 | req = kzalloc(sizeof(*req), GFP_KERNEL); |
924 | if (!req) | |
925 | goto fail; | |
926 | list_add_tail(&req->free_list, &be->blkif->pending_free); | |
927 | for (j = 0; j < MAX_INDIRECT_SEGMENTS; j++) { | |
928 | req->segments[j] = kzalloc(sizeof(*req->segments[0]), GFP_KERNEL); | |
929 | if (!req->segments[j]) | |
930 | goto fail; | |
931 | } | |
932 | for (j = 0; j < MAX_INDIRECT_PAGES; j++) { | |
933 | req->indirect_pages[j] = kzalloc(sizeof(*req->indirect_pages[0]), | |
934 | GFP_KERNEL); | |
935 | if (!req->indirect_pages[j]) | |
936 | goto fail; | |
937 | } | |
938 | } | |
939 | ||
4d05a28d | 940 | /* Map the shared frame, irq etc. */ |
86839c56 | 941 | err = xen_blkif_map(be->blkif, ring_ref, nr_grefs, evtchn); |
4d05a28d | 942 | if (err) { |
86839c56 | 943 | xenbus_dev_fatal(dev, err, "mapping ring-ref port %u", evtchn); |
4d05a28d KRW |
944 | return err; |
945 | } | |
946 | ||
947 | return 0; | |
69b91ede BL |
948 | |
949 | fail: | |
950 | list_for_each_entry_safe(req, n, &be->blkif->pending_free, free_list) { | |
951 | list_del(&req->free_list); | |
952 | for (j = 0; j < MAX_INDIRECT_SEGMENTS; j++) { | |
953 | if (!req->segments[j]) | |
954 | break; | |
955 | kfree(req->segments[j]); | |
956 | } | |
957 | for (j = 0; j < MAX_INDIRECT_PAGES; j++) { | |
958 | if (!req->indirect_pages[j]) | |
959 | break; | |
960 | kfree(req->indirect_pages[j]); | |
961 | } | |
962 | kfree(req); | |
963 | } | |
964 | return -ENOMEM; | |
4d05a28d KRW |
965 | } |
966 | ||
8b6bf747 | 967 | static const struct xenbus_device_id xen_blkbk_ids[] = { |
4d05a28d KRW |
968 | { "vbd" }, |
969 | { "" } | |
970 | }; | |
971 | ||
95afae48 DV |
972 | static struct xenbus_driver xen_blkbk_driver = { |
973 | .ids = xen_blkbk_ids, | |
8b6bf747 KRW |
974 | .probe = xen_blkbk_probe, |
975 | .remove = xen_blkbk_remove, | |
4d05a28d | 976 | .otherend_changed = frontend_changed |
95afae48 | 977 | }; |
4d05a28d | 978 | |
8b6bf747 | 979 | int xen_blkif_xenbus_init(void) |
4d05a28d | 980 | { |
73db144b | 981 | return xenbus_register_backend(&xen_blkbk_driver); |
4d05a28d | 982 | } |