diff options
Diffstat (limited to 'drivers/block/xen-blkback/xenbus.c')
-rw-r--r-- | drivers/block/xen-blkback/xenbus.c | 768 |
1 files changed, 768 insertions, 0 deletions
diff --git a/drivers/block/xen-blkback/xenbus.c b/drivers/block/xen-blkback/xenbus.c new file mode 100644 index 000000000000..34570823355b --- /dev/null +++ b/drivers/block/xen-blkback/xenbus.c | |||
@@ -0,0 +1,768 @@ | |||
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 | |||
15 | */ | ||
16 | |||
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 | |||
24 | struct 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 | |||
33 | static struct kmem_cache *xen_blkif_cachep; | ||
34 | static void connect(struct backend_info *); | ||
35 | static int connect_ring(struct backend_info *); | ||
36 | static void backend_changed(struct xenbus_watch *, const char **, | ||
37 | unsigned int); | ||
38 | |||
39 | struct xenbus_device *xen_blkbk_xenbus(struct backend_info *be) | ||
40 | { | ||
41 | return be->dev; | ||
42 | } | ||
43 | |||
44 | static 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 | |||
65 | static void xen_update_blkif_status(struct xen_blkif *blkif) | ||
66 | { | ||
67 | int err; | ||
68 | char name[TASK_COMM_LEN]; | ||
69 | |||
70 | /* Not ready to connect? */ | ||
71 | if (!blkif->irq || !blkif->vbd.bdev) | ||
72 | return; | ||
73 | |||
74 | /* Already connected? */ | ||
75 | if (blkif->be->dev->state == XenbusStateConnected) | ||
76 | return; | ||
77 | |||
78 | /* Attempt to connect: exit if we fail to. */ | ||
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, 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 | } | ||
102 | } | ||
103 | |||
104 | static struct xen_blkif *xen_blkif_alloc(domid_t domid) | ||
105 | { | ||
106 | struct xen_blkif *blkif; | ||
107 | |||
108 | blkif = kmem_cache_alloc(xen_blkif_cachep, GFP_KERNEL); | ||
109 | if (!blkif) | ||
110 | return ERR_PTR(-ENOMEM); | ||
111 | |||
112 | memset(blkif, 0, sizeof(*blkif)); | ||
113 | blkif->domid = domid; | ||
114 | spin_lock_init(&blkif->blk_ring_lock); | ||
115 | atomic_set(&blkif->refcnt, 1); | ||
116 | init_waitqueue_head(&blkif->wq); | ||
117 | blkif->st_print = jiffies; | ||
118 | init_waitqueue_head(&blkif->waiting_to_free); | ||
119 | |||
120 | return blkif; | ||
121 | } | ||
122 | |||
123 | static int map_frontend_page(struct xen_blkif *blkif, unsigned long shared_page) | ||
124 | { | ||
125 | struct gnttab_map_grant_ref op; | ||
126 | |||
127 | gnttab_set_map_op(&op, (unsigned long)blkif->blk_ring_area->addr, | ||
128 | GNTMAP_host_map, shared_page, blkif->domid); | ||
129 | |||
130 | if (HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, &op, 1)) | ||
131 | BUG(); | ||
132 | |||
133 | if (op.status) { | ||
134 | DPRINTK("Grant table operation failure !\n"); | ||
135 | return op.status; | ||
136 | } | ||
137 | |||
138 | blkif->shmem_ref = shared_page; | ||
139 | blkif->shmem_handle = op.handle; | ||
140 | |||
141 | return 0; | ||
142 | } | ||
143 | |||
144 | static void unmap_frontend_page(struct xen_blkif *blkif) | ||
145 | { | ||
146 | struct gnttab_unmap_grant_ref op; | ||
147 | |||
148 | gnttab_set_unmap_op(&op, (unsigned long)blkif->blk_ring_area->addr, | ||
149 | GNTMAP_host_map, blkif->shmem_handle); | ||
150 | |||
151 | if (HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, &op, 1)) | ||
152 | BUG(); | ||
153 | } | ||
154 | |||
155 | static int xen_blkif_map(struct xen_blkif *blkif, unsigned long shared_page, | ||
156 | unsigned int evtchn) | ||
157 | { | ||
158 | int err; | ||
159 | |||
160 | /* Already connected through? */ | ||
161 | if (blkif->irq) | ||
162 | return 0; | ||
163 | |||
164 | blkif->blk_ring_area = alloc_vm_area(PAGE_SIZE); | ||
165 | if (!blkif->blk_ring_area) | ||
166 | return -ENOMEM; | ||
167 | |||
168 | err = map_frontend_page(blkif, shared_page); | ||
169 | if (err) { | ||
170 | free_vm_area(blkif->blk_ring_area); | ||
171 | return err; | ||
172 | } | ||
173 | |||
174 | switch (blkif->blk_protocol) { | ||
175 | case BLKIF_PROTOCOL_NATIVE: | ||
176 | { | ||
177 | struct blkif_sring *sring; | ||
178 | sring = (struct blkif_sring *)blkif->blk_ring_area->addr; | ||
179 | BACK_RING_INIT(&blkif->blk_rings.native, sring, PAGE_SIZE); | ||
180 | break; | ||
181 | } | ||
182 | case BLKIF_PROTOCOL_X86_32: | ||
183 | { | ||
184 | struct blkif_x86_32_sring *sring_x86_32; | ||
185 | sring_x86_32 = (struct blkif_x86_32_sring *)blkif->blk_ring_area->addr; | ||
186 | BACK_RING_INIT(&blkif->blk_rings.x86_32, sring_x86_32, PAGE_SIZE); | ||
187 | break; | ||
188 | } | ||
189 | case BLKIF_PROTOCOL_X86_64: | ||
190 | { | ||
191 | struct blkif_x86_64_sring *sring_x86_64; | ||
192 | sring_x86_64 = (struct blkif_x86_64_sring *)blkif->blk_ring_area->addr; | ||
193 | BACK_RING_INIT(&blkif->blk_rings.x86_64, sring_x86_64, PAGE_SIZE); | ||
194 | break; | ||
195 | } | ||
196 | default: | ||
197 | BUG(); | ||
198 | } | ||
199 | |||
200 | err = bind_interdomain_evtchn_to_irqhandler(blkif->domid, evtchn, | ||
201 | xen_blkif_be_int, 0, | ||
202 | "blkif-backend", blkif); | ||
203 | if (err < 0) { | ||
204 | unmap_frontend_page(blkif); | ||
205 | free_vm_area(blkif->blk_ring_area); | ||
206 | blkif->blk_rings.common.sring = NULL; | ||
207 | return err; | ||
208 | } | ||
209 | blkif->irq = err; | ||
210 | |||
211 | return 0; | ||
212 | } | ||
213 | |||
214 | static void xen_blkif_disconnect(struct xen_blkif *blkif) | ||
215 | { | ||
216 | if (blkif->xenblkd) { | ||
217 | kthread_stop(blkif->xenblkd); | ||
218 | blkif->xenblkd = NULL; | ||
219 | } | ||
220 | |||
221 | atomic_dec(&blkif->refcnt); | ||
222 | wait_event(blkif->waiting_to_free, atomic_read(&blkif->refcnt) == 0); | ||
223 | atomic_inc(&blkif->refcnt); | ||
224 | |||
225 | if (blkif->irq) { | ||
226 | unbind_from_irqhandler(blkif->irq, blkif); | ||
227 | blkif->irq = 0; | ||
228 | } | ||
229 | |||
230 | if (blkif->blk_rings.common.sring) { | ||
231 | unmap_frontend_page(blkif); | ||
232 | free_vm_area(blkif->blk_ring_area); | ||
233 | blkif->blk_rings.common.sring = NULL; | ||
234 | } | ||
235 | } | ||
236 | |||
237 | void xen_blkif_free(struct xen_blkif *blkif) | ||
238 | { | ||
239 | if (!atomic_dec_and_test(&blkif->refcnt)) | ||
240 | BUG(); | ||
241 | kmem_cache_free(xen_blkif_cachep, blkif); | ||
242 | } | ||
243 | |||
244 | int __init xen_blkif_interface_init(void) | ||
245 | { | ||
246 | xen_blkif_cachep = kmem_cache_create("blkif_cache", | ||
247 | sizeof(struct xen_blkif), | ||
248 | 0, 0, NULL); | ||
249 | if (!xen_blkif_cachep) | ||
250 | return -ENOMEM; | ||
251 | |||
252 | return 0; | ||
253 | } | ||
254 | |||
255 | /* | ||
256 | * sysfs interface for VBD I/O requests | ||
257 | */ | ||
258 | |||
259 | #define VBD_SHOW(name, format, args...) \ | ||
260 | static ssize_t show_##name(struct device *_dev, \ | ||
261 | struct device_attribute *attr, \ | ||
262 | char *buf) \ | ||
263 | { \ | ||
264 | struct xenbus_device *dev = to_xenbus_device(_dev); \ | ||
265 | struct backend_info *be = dev_get_drvdata(&dev->dev); \ | ||
266 | \ | ||
267 | return sprintf(buf, format, ##args); \ | ||
268 | } \ | ||
269 | static DEVICE_ATTR(name, S_IRUGO, show_##name, NULL) | ||
270 | |||
271 | VBD_SHOW(oo_req, "%d\n", be->blkif->st_oo_req); | ||
272 | VBD_SHOW(rd_req, "%d\n", be->blkif->st_rd_req); | ||
273 | VBD_SHOW(wr_req, "%d\n", be->blkif->st_wr_req); | ||
274 | VBD_SHOW(f_req, "%d\n", be->blkif->st_f_req); | ||
275 | VBD_SHOW(rd_sect, "%d\n", be->blkif->st_rd_sect); | ||
276 | VBD_SHOW(wr_sect, "%d\n", be->blkif->st_wr_sect); | ||
277 | |||
278 | static struct attribute *xen_vbdstat_attrs[] = { | ||
279 | &dev_attr_oo_req.attr, | ||
280 | &dev_attr_rd_req.attr, | ||
281 | &dev_attr_wr_req.attr, | ||
282 | &dev_attr_f_req.attr, | ||
283 | &dev_attr_rd_sect.attr, | ||
284 | &dev_attr_wr_sect.attr, | ||
285 | NULL | ||
286 | }; | ||
287 | |||
288 | static struct attribute_group xen_vbdstat_group = { | ||
289 | .name = "statistics", | ||
290 | .attrs = xen_vbdstat_attrs, | ||
291 | }; | ||
292 | |||
293 | VBD_SHOW(physical_device, "%x:%x\n", be->major, be->minor); | ||
294 | VBD_SHOW(mode, "%s\n", be->mode); | ||
295 | |||
296 | int xenvbd_sysfs_addif(struct xenbus_device *dev) | ||
297 | { | ||
298 | int error; | ||
299 | |||
300 | error = device_create_file(&dev->dev, &dev_attr_physical_device); | ||
301 | if (error) | ||
302 | goto fail1; | ||
303 | |||
304 | error = device_create_file(&dev->dev, &dev_attr_mode); | ||
305 | if (error) | ||
306 | goto fail2; | ||
307 | |||
308 | error = sysfs_create_group(&dev->dev.kobj, &xen_vbdstat_group); | ||
309 | if (error) | ||
310 | goto fail3; | ||
311 | |||
312 | return 0; | ||
313 | |||
314 | fail3: sysfs_remove_group(&dev->dev.kobj, &xen_vbdstat_group); | ||
315 | fail2: device_remove_file(&dev->dev, &dev_attr_mode); | ||
316 | fail1: device_remove_file(&dev->dev, &dev_attr_physical_device); | ||
317 | return error; | ||
318 | } | ||
319 | |||
320 | void xenvbd_sysfs_delif(struct xenbus_device *dev) | ||
321 | { | ||
322 | sysfs_remove_group(&dev->dev.kobj, &xen_vbdstat_group); | ||
323 | device_remove_file(&dev->dev, &dev_attr_mode); | ||
324 | device_remove_file(&dev->dev, &dev_attr_physical_device); | ||
325 | } | ||
326 | |||
327 | |||
328 | static void xen_vbd_free(struct xen_vbd *vbd) | ||
329 | { | ||
330 | if (vbd->bdev) | ||
331 | blkdev_put(vbd->bdev, vbd->readonly ? FMODE_READ : FMODE_WRITE); | ||
332 | vbd->bdev = NULL; | ||
333 | } | ||
334 | |||
335 | static int xen_vbd_create(struct xen_blkif *blkif, blkif_vdev_t handle, | ||
336 | unsigned major, unsigned minor, int readonly, | ||
337 | int cdrom) | ||
338 | { | ||
339 | struct xen_vbd *vbd; | ||
340 | struct block_device *bdev; | ||
341 | struct request_queue *q; | ||
342 | |||
343 | vbd = &blkif->vbd; | ||
344 | vbd->handle = handle; | ||
345 | vbd->readonly = readonly; | ||
346 | vbd->type = 0; | ||
347 | |||
348 | vbd->pdevice = MKDEV(major, minor); | ||
349 | |||
350 | bdev = blkdev_get_by_dev(vbd->pdevice, vbd->readonly ? | ||
351 | FMODE_READ : FMODE_WRITE, NULL); | ||
352 | |||
353 | if (IS_ERR(bdev)) { | ||
354 | DPRINTK("xen_vbd_create: device %08x could not be opened.\n", | ||
355 | vbd->pdevice); | ||
356 | return -ENOENT; | ||
357 | } | ||
358 | |||
359 | vbd->bdev = bdev; | ||
360 | vbd->size = vbd_sz(vbd); | ||
361 | |||
362 | if (vbd->bdev->bd_disk == NULL) { | ||
363 | DPRINTK("xen_vbd_create: device %08x doesn't exist.\n", | ||
364 | vbd->pdevice); | ||
365 | xen_vbd_free(vbd); | ||
366 | return -ENOENT; | ||
367 | } | ||
368 | |||
369 | if (vbd->bdev->bd_disk->flags & GENHD_FL_CD || cdrom) | ||
370 | vbd->type |= VDISK_CDROM; | ||
371 | if (vbd->bdev->bd_disk->flags & GENHD_FL_REMOVABLE) | ||
372 | vbd->type |= VDISK_REMOVABLE; | ||
373 | |||
374 | q = bdev_get_queue(bdev); | ||
375 | if (q && q->flush_flags) | ||
376 | vbd->flush_support = true; | ||
377 | |||
378 | DPRINTK("Successful creation of handle=%04x (dom=%u)\n", | ||
379 | handle, blkif->domid); | ||
380 | return 0; | ||
381 | } | ||
382 | static int xen_blkbk_remove(struct xenbus_device *dev) | ||
383 | { | ||
384 | struct backend_info *be = dev_get_drvdata(&dev->dev); | ||
385 | |||
386 | DPRINTK(""); | ||
387 | |||
388 | if (be->major || be->minor) | ||
389 | xenvbd_sysfs_delif(dev); | ||
390 | |||
391 | if (be->backend_watch.node) { | ||
392 | unregister_xenbus_watch(&be->backend_watch); | ||
393 | kfree(be->backend_watch.node); | ||
394 | be->backend_watch.node = NULL; | ||
395 | } | ||
396 | |||
397 | if (be->blkif) { | ||
398 | xen_blkif_disconnect(be->blkif); | ||
399 | xen_vbd_free(&be->blkif->vbd); | ||
400 | xen_blkif_free(be->blkif); | ||
401 | be->blkif = NULL; | ||
402 | } | ||
403 | |||
404 | kfree(be); | ||
405 | dev_set_drvdata(&dev->dev, NULL); | ||
406 | return 0; | ||
407 | } | ||
408 | |||
409 | int xen_blkbk_flush_diskcache(struct xenbus_transaction xbt, | ||
410 | struct backend_info *be, int state) | ||
411 | { | ||
412 | struct xenbus_device *dev = be->dev; | ||
413 | int err; | ||
414 | |||
415 | err = xenbus_printf(xbt, dev->nodename, "feature-flush-cache", | ||
416 | "%d", state); | ||
417 | if (err) | ||
418 | xenbus_dev_fatal(dev, err, "writing feature-flush-cache"); | ||
419 | |||
420 | return err; | ||
421 | } | ||
422 | |||
423 | /* | ||
424 | * Entry point to this code when a new device is created. Allocate the basic | ||
425 | * structures, and watch the store waiting for the hotplug scripts to tell us | ||
426 | * the device's physical major and minor numbers. Switch to InitWait. | ||
427 | */ | ||
428 | static int xen_blkbk_probe(struct xenbus_device *dev, | ||
429 | const struct xenbus_device_id *id) | ||
430 | { | ||
431 | int err; | ||
432 | struct backend_info *be = kzalloc(sizeof(struct backend_info), | ||
433 | GFP_KERNEL); | ||
434 | if (!be) { | ||
435 | xenbus_dev_fatal(dev, -ENOMEM, | ||
436 | "allocating backend structure"); | ||
437 | return -ENOMEM; | ||
438 | } | ||
439 | be->dev = dev; | ||
440 | dev_set_drvdata(&dev->dev, be); | ||
441 | |||
442 | be->blkif = xen_blkif_alloc(dev->otherend_id); | ||
443 | if (IS_ERR(be->blkif)) { | ||
444 | err = PTR_ERR(be->blkif); | ||
445 | be->blkif = NULL; | ||
446 | xenbus_dev_fatal(dev, err, "creating block interface"); | ||
447 | goto fail; | ||
448 | } | ||
449 | |||
450 | /* setup back pointer */ | ||
451 | be->blkif->be = be; | ||
452 | |||
453 | err = xenbus_watch_pathfmt(dev, &be->backend_watch, backend_changed, | ||
454 | "%s/%s", dev->nodename, "physical-device"); | ||
455 | if (err) | ||
456 | goto fail; | ||
457 | |||
458 | err = xenbus_switch_state(dev, XenbusStateInitWait); | ||
459 | if (err) | ||
460 | goto fail; | ||
461 | |||
462 | return 0; | ||
463 | |||
464 | fail: | ||
465 | DPRINTK("failed"); | ||
466 | xen_blkbk_remove(dev); | ||
467 | return err; | ||
468 | } | ||
469 | |||
470 | |||
471 | /* | ||
472 | * Callback received when the hotplug scripts have placed the physical-device | ||
473 | * node. Read it and the mode node, and create a vbd. If the frontend is | ||
474 | * ready, connect. | ||
475 | */ | ||
476 | static void backend_changed(struct xenbus_watch *watch, | ||
477 | const char **vec, unsigned int len) | ||
478 | { | ||
479 | int err; | ||
480 | unsigned major; | ||
481 | unsigned minor; | ||
482 | struct backend_info *be | ||
483 | = container_of(watch, struct backend_info, backend_watch); | ||
484 | struct xenbus_device *dev = be->dev; | ||
485 | int cdrom = 0; | ||
486 | char *device_type; | ||
487 | |||
488 | DPRINTK(""); | ||
489 | |||
490 | err = xenbus_scanf(XBT_NIL, dev->nodename, "physical-device", "%x:%x", | ||
491 | &major, &minor); | ||
492 | if (XENBUS_EXIST_ERR(err)) { | ||
493 | /* | ||
494 | * Since this watch will fire once immediately after it is | ||
495 | * registered, we expect this. Ignore it, and wait for the | ||
496 | * hotplug scripts. | ||
497 | */ | ||
498 | return; | ||
499 | } | ||
500 | if (err != 2) { | ||
501 | xenbus_dev_fatal(dev, err, "reading physical-device"); | ||
502 | return; | ||
503 | } | ||
504 | |||
505 | if ((be->major || be->minor) && | ||
506 | ((be->major != major) || (be->minor != minor))) { | ||
507 | pr_warn(DRV_PFX "changing physical device (from %x:%x to %x:%x) not supported.\n", | ||
508 | be->major, be->minor, major, minor); | ||
509 | return; | ||
510 | } | ||
511 | |||
512 | be->mode = xenbus_read(XBT_NIL, dev->nodename, "mode", NULL); | ||
513 | if (IS_ERR(be->mode)) { | ||
514 | err = PTR_ERR(be->mode); | ||
515 | be->mode = NULL; | ||
516 | xenbus_dev_fatal(dev, err, "reading mode"); | ||
517 | return; | ||
518 | } | ||
519 | |||
520 | device_type = xenbus_read(XBT_NIL, dev->otherend, "device-type", NULL); | ||
521 | if (!IS_ERR(device_type)) { | ||
522 | cdrom = strcmp(device_type, "cdrom") == 0; | ||
523 | kfree(device_type); | ||
524 | } | ||
525 | |||
526 | if (be->major == 0 && be->minor == 0) { | ||
527 | /* Front end dir is a number, which is used as the handle. */ | ||
528 | |||
529 | char *p = strrchr(dev->otherend, '/') + 1; | ||
530 | long handle; | ||
531 | err = strict_strtoul(p, 0, &handle); | ||
532 | if (err) | ||
533 | return; | ||
534 | |||
535 | be->major = major; | ||
536 | be->minor = minor; | ||
537 | |||
538 | err = xen_vbd_create(be->blkif, handle, major, minor, | ||
539 | (NULL == strchr(be->mode, 'w')), cdrom); | ||
540 | if (err) { | ||
541 | be->major = 0; | ||
542 | be->minor = 0; | ||
543 | xenbus_dev_fatal(dev, err, "creating vbd structure"); | ||
544 | return; | ||
545 | } | ||
546 | |||
547 | err = xenvbd_sysfs_addif(dev); | ||
548 | if (err) { | ||
549 | xen_vbd_free(&be->blkif->vbd); | ||
550 | be->major = 0; | ||
551 | be->minor = 0; | ||
552 | xenbus_dev_fatal(dev, err, "creating sysfs entries"); | ||
553 | return; | ||
554 | } | ||
555 | |||
556 | /* We're potentially connected now */ | ||
557 | xen_update_blkif_status(be->blkif); | ||
558 | } | ||
559 | } | ||
560 | |||
561 | |||
562 | /* | ||
563 | * Callback received when the frontend's state changes. | ||
564 | */ | ||
565 | static void frontend_changed(struct xenbus_device *dev, | ||
566 | enum xenbus_state frontend_state) | ||
567 | { | ||
568 | struct backend_info *be = dev_get_drvdata(&dev->dev); | ||
569 | int err; | ||
570 | |||
571 | DPRINTK("%s", xenbus_strstate(frontend_state)); | ||
572 | |||
573 | switch (frontend_state) { | ||
574 | case XenbusStateInitialising: | ||
575 | if (dev->state == XenbusStateClosed) { | ||
576 | pr_info(DRV_PFX "%s: prepare for reconnect\n", | ||
577 | dev->nodename); | ||
578 | xenbus_switch_state(dev, XenbusStateInitWait); | ||
579 | } | ||
580 | break; | ||
581 | |||
582 | case XenbusStateInitialised: | ||
583 | case XenbusStateConnected: | ||
584 | /* | ||
585 | * Ensure we connect even when two watches fire in | ||
586 | * close successsion and we miss the intermediate value | ||
587 | * of frontend_state. | ||
588 | */ | ||
589 | if (dev->state == XenbusStateConnected) | ||
590 | break; | ||
591 | |||
592 | /* | ||
593 | * Enforce precondition before potential leak point. | ||
594 | * blkif_disconnect() is idempotent. | ||
595 | */ | ||
596 | xen_blkif_disconnect(be->blkif); | ||
597 | |||
598 | err = connect_ring(be); | ||
599 | if (err) | ||
600 | break; | ||
601 | xen_update_blkif_status(be->blkif); | ||
602 | break; | ||
603 | |||
604 | case XenbusStateClosing: | ||
605 | xen_blkif_disconnect(be->blkif); | ||
606 | xenbus_switch_state(dev, XenbusStateClosing); | ||
607 | break; | ||
608 | |||
609 | case XenbusStateClosed: | ||
610 | xenbus_switch_state(dev, XenbusStateClosed); | ||
611 | if (xenbus_dev_is_online(dev)) | ||
612 | break; | ||
613 | /* fall through if not online */ | ||
614 | case XenbusStateUnknown: | ||
615 | /* implies blkif_disconnect() via blkback_remove() */ | ||
616 | device_unregister(&dev->dev); | ||
617 | break; | ||
618 | |||
619 | default: | ||
620 | xenbus_dev_fatal(dev, -EINVAL, "saw state %d at frontend", | ||
621 | frontend_state); | ||
622 | break; | ||
623 | } | ||
624 | } | ||
625 | |||
626 | |||
627 | /* ** Connection ** */ | ||
628 | |||
629 | |||
630 | /* | ||
631 | * Write the physical details regarding the block device to the store, and | ||
632 | * switch to Connected state. | ||
633 | */ | ||
634 | static void connect(struct backend_info *be) | ||
635 | { | ||
636 | struct xenbus_transaction xbt; | ||
637 | int err; | ||
638 | struct xenbus_device *dev = be->dev; | ||
639 | |||
640 | DPRINTK("%s", dev->otherend); | ||
641 | |||
642 | /* Supply the information about the device the frontend needs */ | ||
643 | again: | ||
644 | err = xenbus_transaction_start(&xbt); | ||
645 | if (err) { | ||
646 | xenbus_dev_fatal(dev, err, "starting transaction"); | ||
647 | return; | ||
648 | } | ||
649 | |||
650 | err = xen_blkbk_flush_diskcache(xbt, be, be->blkif->vbd.flush_support); | ||
651 | if (err) | ||
652 | goto abort; | ||
653 | |||
654 | err = xenbus_printf(xbt, dev->nodename, "sectors", "%llu", | ||
655 | (unsigned long long)vbd_sz(&be->blkif->vbd)); | ||
656 | if (err) { | ||
657 | xenbus_dev_fatal(dev, err, "writing %s/sectors", | ||
658 | dev->nodename); | ||
659 | goto abort; | ||
660 | } | ||
661 | |||
662 | /* FIXME: use a typename instead */ | ||
663 | err = xenbus_printf(xbt, dev->nodename, "info", "%u", | ||
664 | be->blkif->vbd.type | | ||
665 | (be->blkif->vbd.readonly ? VDISK_READONLY : 0)); | ||
666 | if (err) { | ||
667 | xenbus_dev_fatal(dev, err, "writing %s/info", | ||
668 | dev->nodename); | ||
669 | goto abort; | ||
670 | } | ||
671 | err = xenbus_printf(xbt, dev->nodename, "sector-size", "%lu", | ||
672 | (unsigned long) | ||
673 | bdev_logical_block_size(be->blkif->vbd.bdev)); | ||
674 | if (err) { | ||
675 | xenbus_dev_fatal(dev, err, "writing %s/sector-size", | ||
676 | dev->nodename); | ||
677 | goto abort; | ||
678 | } | ||
679 | |||
680 | err = xenbus_transaction_end(xbt, 0); | ||
681 | if (err == -EAGAIN) | ||
682 | goto again; | ||
683 | if (err) | ||
684 | xenbus_dev_fatal(dev, err, "ending transaction"); | ||
685 | |||
686 | err = xenbus_switch_state(dev, XenbusStateConnected); | ||
687 | if (err) | ||
688 | xenbus_dev_fatal(dev, err, "switching to Connected state", | ||
689 | dev->nodename); | ||
690 | |||
691 | return; | ||
692 | abort: | ||
693 | xenbus_transaction_end(xbt, 1); | ||
694 | } | ||
695 | |||
696 | |||
697 | static int connect_ring(struct backend_info *be) | ||
698 | { | ||
699 | struct xenbus_device *dev = be->dev; | ||
700 | unsigned long ring_ref; | ||
701 | unsigned int evtchn; | ||
702 | char protocol[64] = ""; | ||
703 | int err; | ||
704 | |||
705 | DPRINTK("%s", dev->otherend); | ||
706 | |||
707 | err = xenbus_gather(XBT_NIL, dev->otherend, "ring-ref", "%lu", | ||
708 | &ring_ref, "event-channel", "%u", &evtchn, NULL); | ||
709 | if (err) { | ||
710 | xenbus_dev_fatal(dev, err, | ||
711 | "reading %s/ring-ref and event-channel", | ||
712 | dev->otherend); | ||
713 | return err; | ||
714 | } | ||
715 | |||
716 | be->blkif->blk_protocol = BLKIF_PROTOCOL_NATIVE; | ||
717 | err = xenbus_gather(XBT_NIL, dev->otherend, "protocol", | ||
718 | "%63s", protocol, NULL); | ||
719 | if (err) | ||
720 | strcpy(protocol, "unspecified, assuming native"); | ||
721 | else if (0 == strcmp(protocol, XEN_IO_PROTO_ABI_NATIVE)) | ||
722 | be->blkif->blk_protocol = BLKIF_PROTOCOL_NATIVE; | ||
723 | else if (0 == strcmp(protocol, XEN_IO_PROTO_ABI_X86_32)) | ||
724 | be->blkif->blk_protocol = BLKIF_PROTOCOL_X86_32; | ||
725 | else if (0 == strcmp(protocol, XEN_IO_PROTO_ABI_X86_64)) | ||
726 | be->blkif->blk_protocol = BLKIF_PROTOCOL_X86_64; | ||
727 | else { | ||
728 | xenbus_dev_fatal(dev, err, "unknown fe protocol %s", protocol); | ||
729 | return -1; | ||
730 | } | ||
731 | pr_info(DRV_PFX "ring-ref %ld, event-channel %d, protocol %d (%s)\n", | ||
732 | ring_ref, evtchn, be->blkif->blk_protocol, protocol); | ||
733 | |||
734 | /* Map the shared frame, irq etc. */ | ||
735 | err = xen_blkif_map(be->blkif, ring_ref, evtchn); | ||
736 | if (err) { | ||
737 | xenbus_dev_fatal(dev, err, "mapping ring-ref %lu port %u", | ||
738 | ring_ref, evtchn); | ||
739 | return err; | ||
740 | } | ||
741 | |||
742 | return 0; | ||
743 | } | ||
744 | |||
745 | |||
746 | /* ** Driver Registration ** */ | ||
747 | |||
748 | |||
749 | static const struct xenbus_device_id xen_blkbk_ids[] = { | ||
750 | { "vbd" }, | ||
751 | { "" } | ||
752 | }; | ||
753 | |||
754 | |||
755 | static struct xenbus_driver xen_blkbk = { | ||
756 | .name = "vbd", | ||
757 | .owner = THIS_MODULE, | ||
758 | .ids = xen_blkbk_ids, | ||
759 | .probe = xen_blkbk_probe, | ||
760 | .remove = xen_blkbk_remove, | ||
761 | .otherend_changed = frontend_changed | ||
762 | }; | ||
763 | |||
764 | |||
765 | int xen_blkif_xenbus_init(void) | ||
766 | { | ||
767 | return xenbus_register_backend(&xen_blkbk); | ||
768 | } | ||