Commit | Line | Data |
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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 | ||
17 | #include <stdarg.h> | |
18 | #include <linux/module.h> | |
19 | #include <linux/kthread.h> | |
ee9ff853 KRW |
20 | #include <xen/events.h> |
21 | #include <xen/grant_table.h> | |
4d05a28d KRW |
22 | #include "common.h" |
23 | ||
d6091b21 | 24 | struct backend_info { |
01f37f2d KRW |
25 | struct xenbus_device *dev; |
26 | struct blkif_st *blkif; | |
27 | struct xenbus_watch backend_watch; | |
28 | unsigned major; | |
29 | unsigned minor; | |
30 | char *mode; | |
4d05a28d KRW |
31 | }; |
32 | ||
8b6bf747 | 33 | static struct kmem_cache *xen_blkif_cachep; |
4d05a28d KRW |
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 | ||
8b6bf747 | 39 | struct xenbus_device *xen_blkbk_xenbus(struct backend_info *be) |
98e036a3 JF |
40 | { |
41 | return be->dev; | |
42 | } | |
43 | ||
5489377c | 44 | static int blkback_name(struct blkif_st *blkif, char *buf) |
4d05a28d KRW |
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 | ||
d6091b21 KRW |
53 | devname = strstr(devpath, "/dev/"); |
54 | if (devname != NULL) | |
4d05a28d KRW |
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 | ||
8b6bf747 | 65 | static void xen_update_blkif_status(struct blkif_st *blkif) |
4d05a28d KRW |
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 | ||
cbf46290 CL |
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 | ||
8b6bf747 | 96 | blkif->xenblkd = kthread_run(xen_blkif_schedule, blkif, name); |
4d05a28d KRW |
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 | ||
8b6bf747 | 104 | static struct blkif_st *xen_blkif_alloc(domid_t domid) |
ee9ff853 KRW |
105 | { |
106 | struct blkif_st *blkif; | |
107 | ||
8b6bf747 | 108 | blkif = kmem_cache_alloc(xen_blkif_cachep, GFP_KERNEL); |
ee9ff853 KRW |
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 blkif_st *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) { | |
ebe81906 | 134 | DPRINTK("Grant table operation failure !\n"); |
ee9ff853 KRW |
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 blkif_st *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 | ||
8b6bf747 KRW |
155 | static int xen_blkif_map(struct blkif_st *blkif, unsigned long shared_page, |
156 | unsigned int evtchn) | |
ee9ff853 KRW |
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 | ||
8b6bf747 KRW |
200 | err = bind_interdomain_evtchn_to_irqhandler(blkif->domid, evtchn, |
201 | xen_blkif_be_int, 0, | |
202 | "blkif-backend", blkif); | |
ee9ff853 KRW |
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 | ||
8b6bf747 | 214 | static void xen_blkif_disconnect(struct blkif_st *blkif) |
ee9ff853 KRW |
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 | ||
8b6bf747 | 237 | void xen_blkif_free(struct blkif_st *blkif) |
ee9ff853 KRW |
238 | { |
239 | if (!atomic_dec_and_test(&blkif->refcnt)) | |
240 | BUG(); | |
8b6bf747 | 241 | kmem_cache_free(xen_blkif_cachep, blkif); |
ee9ff853 KRW |
242 | } |
243 | ||
8b6bf747 | 244 | int __init xen_blkif_interface_init(void) |
ee9ff853 | 245 | { |
8b6bf747 KRW |
246 | xen_blkif_cachep = kmem_cache_create("blkif_cache", |
247 | sizeof(struct blkif_st), | |
248 | 0, 0, NULL); | |
249 | if (!xen_blkif_cachep) | |
ee9ff853 KRW |
250 | return -ENOMEM; |
251 | ||
252 | return 0; | |
253 | } | |
4d05a28d | 254 | |
a1397fa3 | 255 | /* |
4d05a28d KRW |
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); \ | |
5cf6e4f6 | 265 | struct backend_info *be = dev_get_drvdata(&dev->dev); \ |
4d05a28d KRW |
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); | |
24f567f9 | 274 | VBD_SHOW(f_req, "%d\n", be->blkif->st_f_req); |
4d05a28d KRW |
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 *vbdstat_attrs[] = { | |
279 | &dev_attr_oo_req.attr, | |
280 | &dev_attr_rd_req.attr, | |
281 | &dev_attr_wr_req.attr, | |
24f567f9 | 282 | &dev_attr_f_req.attr, |
4d05a28d KRW |
283 | &dev_attr_rd_sect.attr, |
284 | &dev_attr_wr_sect.attr, | |
285 | NULL | |
286 | }; | |
287 | ||
288 | static struct attribute_group vbdstat_group = { | |
289 | .name = "statistics", | |
290 | .attrs = 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); | |
d6091b21 | 301 | if (error) |
4d05a28d KRW |
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, &vbdstat_group); | |
309 | if (error) | |
310 | goto fail3; | |
311 | ||
312 | return 0; | |
313 | ||
314 | fail3: sysfs_remove_group(&dev->dev.kobj, &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, &vbdstat_group); | |
323 | device_remove_file(&dev->dev, &dev_attr_mode); | |
324 | device_remove_file(&dev->dev, &dev_attr_physical_device); | |
325 | } | |
326 | ||
42c7841d KRW |
327 | |
328 | static void vbd_free(struct 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 vbd_create(struct blkif_st *blkif, blkif_vdev_t handle, | |
336 | unsigned major, unsigned minor, int readonly, | |
337 | int cdrom) | |
338 | { | |
339 | struct vbd *vbd; | |
340 | struct block_device *bdev; | |
24f567f9 | 341 | struct request_queue *q; |
42c7841d KRW |
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("vbd_creat: 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("vbd_creat: device %08x doesn't exist.\n", | |
364 | vbd->pdevice); | |
365 | 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 | ||
24f567f9 KRW |
374 | q = bdev_get_queue(bdev); |
375 | if (q && q->flush_flags) | |
376 | vbd->flush_support = true; | |
377 | ||
42c7841d KRW |
378 | DPRINTK("Successful creation of handle=%04x (dom=%u)\n", |
379 | handle, blkif->domid); | |
380 | return 0; | |
381 | } | |
8b6bf747 | 382 | static int xen_blkbk_remove(struct xenbus_device *dev) |
4d05a28d | 383 | { |
5cf6e4f6 | 384 | struct backend_info *be = dev_get_drvdata(&dev->dev); |
4d05a28d KRW |
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) { | |
8b6bf747 | 398 | xen_blkif_disconnect(be->blkif); |
4d05a28d | 399 | vbd_free(&be->blkif->vbd); |
8b6bf747 | 400 | xen_blkif_free(be->blkif); |
4d05a28d KRW |
401 | be->blkif = NULL; |
402 | } | |
403 | ||
404 | kfree(be); | |
5cf6e4f6 | 405 | dev_set_drvdata(&dev->dev, NULL); |
4d05a28d KRW |
406 | return 0; |
407 | } | |
408 | ||
24f567f9 KRW |
409 | int xen_blkbk_flush_diskcache(struct xenbus_transaction xbt, |
410 | struct backend_info *be, int state) | |
4d05a28d KRW |
411 | { |
412 | struct xenbus_device *dev = be->dev; | |
413 | int err; | |
414 | ||
24f567f9 | 415 | err = xenbus_printf(xbt, dev->nodename, "feature-flush-cache", |
4d05a28d KRW |
416 | "%d", state); |
417 | if (err) | |
24f567f9 | 418 | xenbus_dev_fatal(dev, err, "writing feature-flush-cache"); |
4d05a28d KRW |
419 | |
420 | return err; | |
421 | } | |
422 | ||
01f37f2d | 423 | /* |
4d05a28d KRW |
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 | */ | |
8b6bf747 KRW |
428 | static int xen_blkbk_probe(struct xenbus_device *dev, |
429 | const struct xenbus_device_id *id) | |
4d05a28d KRW |
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; | |
5cf6e4f6 | 440 | dev_set_drvdata(&dev->dev, be); |
4d05a28d | 441 | |
8b6bf747 | 442 | be->blkif = xen_blkif_alloc(dev->otherend_id); |
4d05a28d KRW |
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 | ||
88122933 JF |
453 | err = xenbus_watch_pathfmt(dev, &be->backend_watch, backend_changed, |
454 | "%s/%s", dev->nodename, "physical-device"); | |
4d05a28d KRW |
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"); | |
8b6bf747 | 466 | xen_blkbk_remove(dev); |
4d05a28d KRW |
467 | return err; |
468 | } | |
469 | ||
470 | ||
01f37f2d | 471 | /* |
4d05a28d KRW |
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)) { | |
01f37f2d KRW |
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 | */ | |
4d05a28d KRW |
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))) { | |
22b20f2d | 507 | pr_warn(DRV_PFX "changing physical device (from %x:%x to %x:%x) not supported.\n", |
ebe81906 | 508 | be->major, be->minor, major, minor); |
4d05a28d KRW |
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; | |
d6091b21 KRW |
530 | long handle; |
531 | err = strict_strtoul(p, 0, &handle); | |
532 | if (err) | |
533 | return; | |
4d05a28d KRW |
534 | |
535 | be->major = major; | |
536 | be->minor = minor; | |
537 | ||
538 | err = vbd_create(be->blkif, handle, major, minor, | |
539 | (NULL == strchr(be->mode, 'w')), cdrom); | |
540 | if (err) { | |
541 | be->major = be->minor = 0; | |
542 | xenbus_dev_fatal(dev, err, "creating vbd structure"); | |
543 | return; | |
544 | } | |
545 | ||
546 | err = xenvbd_sysfs_addif(dev); | |
547 | if (err) { | |
548 | vbd_free(&be->blkif->vbd); | |
549 | be->major = be->minor = 0; | |
550 | xenbus_dev_fatal(dev, err, "creating sysfs entries"); | |
551 | return; | |
552 | } | |
553 | ||
554 | /* We're potentially connected now */ | |
8b6bf747 | 555 | xen_update_blkif_status(be->blkif); |
4d05a28d KRW |
556 | } |
557 | } | |
558 | ||
559 | ||
01f37f2d | 560 | /* |
4d05a28d KRW |
561 | * Callback received when the frontend's state changes. |
562 | */ | |
563 | static void frontend_changed(struct xenbus_device *dev, | |
564 | enum xenbus_state frontend_state) | |
565 | { | |
5cf6e4f6 | 566 | struct backend_info *be = dev_get_drvdata(&dev->dev); |
4d05a28d KRW |
567 | int err; |
568 | ||
569 | DPRINTK("%s", xenbus_strstate(frontend_state)); | |
570 | ||
571 | switch (frontend_state) { | |
572 | case XenbusStateInitialising: | |
573 | if (dev->state == XenbusStateClosed) { | |
22b20f2d | 574 | pr_info(DRV_PFX "%s: prepare for reconnect\n", |
ebe81906 | 575 | dev->nodename); |
4d05a28d KRW |
576 | xenbus_switch_state(dev, XenbusStateInitWait); |
577 | } | |
578 | break; | |
579 | ||
580 | case XenbusStateInitialised: | |
581 | case XenbusStateConnected: | |
01f37f2d KRW |
582 | /* |
583 | * Ensure we connect even when two watches fire in | |
584 | * close successsion and we miss the intermediate value | |
585 | * of frontend_state. | |
586 | */ | |
4d05a28d KRW |
587 | if (dev->state == XenbusStateConnected) |
588 | break; | |
589 | ||
01f37f2d KRW |
590 | /* |
591 | * Enforce precondition before potential leak point. | |
313d7b00 KF |
592 | * blkif_disconnect() is idempotent. |
593 | */ | |
8b6bf747 | 594 | xen_blkif_disconnect(be->blkif); |
313d7b00 | 595 | |
4d05a28d KRW |
596 | err = connect_ring(be); |
597 | if (err) | |
598 | break; | |
8b6bf747 | 599 | xen_update_blkif_status(be->blkif); |
4d05a28d KRW |
600 | break; |
601 | ||
602 | case XenbusStateClosing: | |
8b6bf747 | 603 | xen_blkif_disconnect(be->blkif); |
4d05a28d KRW |
604 | xenbus_switch_state(dev, XenbusStateClosing); |
605 | break; | |
606 | ||
607 | case XenbusStateClosed: | |
608 | xenbus_switch_state(dev, XenbusStateClosed); | |
609 | if (xenbus_dev_is_online(dev)) | |
610 | break; | |
611 | /* fall through if not online */ | |
612 | case XenbusStateUnknown: | |
313d7b00 | 613 | /* implies blkif_disconnect() via blkback_remove() */ |
4d05a28d KRW |
614 | device_unregister(&dev->dev); |
615 | break; | |
616 | ||
617 | default: | |
618 | xenbus_dev_fatal(dev, -EINVAL, "saw state %d at frontend", | |
619 | frontend_state); | |
620 | break; | |
621 | } | |
622 | } | |
623 | ||
624 | ||
625 | /* ** Connection ** */ | |
626 | ||
627 | ||
01f37f2d | 628 | /* |
4d05a28d KRW |
629 | * Write the physical details regarding the block device to the store, and |
630 | * switch to Connected state. | |
631 | */ | |
632 | static void connect(struct backend_info *be) | |
633 | { | |
634 | struct xenbus_transaction xbt; | |
635 | int err; | |
636 | struct xenbus_device *dev = be->dev; | |
637 | ||
638 | DPRINTK("%s", dev->otherend); | |
639 | ||
640 | /* Supply the information about the device the frontend needs */ | |
641 | again: | |
642 | err = xenbus_transaction_start(&xbt); | |
643 | if (err) { | |
644 | xenbus_dev_fatal(dev, err, "starting transaction"); | |
645 | return; | |
646 | } | |
647 | ||
24f567f9 | 648 | err = xen_blkbk_flush_diskcache(xbt, be, be->blkif->vbd.flush_support); |
4d05a28d KRW |
649 | if (err) |
650 | goto abort; | |
651 | ||
652 | err = xenbus_printf(xbt, dev->nodename, "sectors", "%llu", | |
42c7841d | 653 | (unsigned long long)vbd_sz(&be->blkif->vbd)); |
4d05a28d KRW |
654 | if (err) { |
655 | xenbus_dev_fatal(dev, err, "writing %s/sectors", | |
656 | dev->nodename); | |
657 | goto abort; | |
658 | } | |
659 | ||
660 | /* FIXME: use a typename instead */ | |
661 | err = xenbus_printf(xbt, dev->nodename, "info", "%u", | |
42c7841d KRW |
662 | be->blkif->vbd.type | |
663 | (be->blkif->vbd.readonly ? VDISK_READONLY : 0)); | |
4d05a28d KRW |
664 | if (err) { |
665 | xenbus_dev_fatal(dev, err, "writing %s/info", | |
666 | dev->nodename); | |
667 | goto abort; | |
668 | } | |
669 | err = xenbus_printf(xbt, dev->nodename, "sector-size", "%lu", | |
42c7841d KRW |
670 | (unsigned long) |
671 | bdev_logical_block_size(be->blkif->vbd.bdev)); | |
4d05a28d KRW |
672 | if (err) { |
673 | xenbus_dev_fatal(dev, err, "writing %s/sector-size", | |
674 | dev->nodename); | |
675 | goto abort; | |
676 | } | |
677 | ||
678 | err = xenbus_transaction_end(xbt, 0); | |
679 | if (err == -EAGAIN) | |
680 | goto again; | |
681 | if (err) | |
682 | xenbus_dev_fatal(dev, err, "ending transaction"); | |
683 | ||
684 | err = xenbus_switch_state(dev, XenbusStateConnected); | |
685 | if (err) | |
686 | xenbus_dev_fatal(dev, err, "switching to Connected state", | |
687 | dev->nodename); | |
688 | ||
689 | return; | |
690 | abort: | |
691 | xenbus_transaction_end(xbt, 1); | |
692 | } | |
693 | ||
694 | ||
695 | static int connect_ring(struct backend_info *be) | |
696 | { | |
697 | struct xenbus_device *dev = be->dev; | |
698 | unsigned long ring_ref; | |
699 | unsigned int evtchn; | |
700 | char protocol[64] = ""; | |
701 | int err; | |
702 | ||
703 | DPRINTK("%s", dev->otherend); | |
704 | ||
d6091b21 KRW |
705 | err = xenbus_gather(XBT_NIL, dev->otherend, "ring-ref", "%lu", |
706 | &ring_ref, "event-channel", "%u", &evtchn, NULL); | |
4d05a28d KRW |
707 | if (err) { |
708 | xenbus_dev_fatal(dev, err, | |
709 | "reading %s/ring-ref and event-channel", | |
710 | dev->otherend); | |
711 | return err; | |
712 | } | |
713 | ||
714 | be->blkif->blk_protocol = BLKIF_PROTOCOL_NATIVE; | |
715 | err = xenbus_gather(XBT_NIL, dev->otherend, "protocol", | |
716 | "%63s", protocol, NULL); | |
717 | if (err) | |
718 | strcpy(protocol, "unspecified, assuming native"); | |
719 | else if (0 == strcmp(protocol, XEN_IO_PROTO_ABI_NATIVE)) | |
720 | be->blkif->blk_protocol = BLKIF_PROTOCOL_NATIVE; | |
721 | else if (0 == strcmp(protocol, XEN_IO_PROTO_ABI_X86_32)) | |
722 | be->blkif->blk_protocol = BLKIF_PROTOCOL_X86_32; | |
723 | else if (0 == strcmp(protocol, XEN_IO_PROTO_ABI_X86_64)) | |
724 | be->blkif->blk_protocol = BLKIF_PROTOCOL_X86_64; | |
725 | else { | |
726 | xenbus_dev_fatal(dev, err, "unknown fe protocol %s", protocol); | |
727 | return -1; | |
728 | } | |
22b20f2d | 729 | pr_info(DRV_PFX "ring-ref %ld, event-channel %d, protocol %d (%s)\n", |
ebe81906 | 730 | ring_ref, evtchn, be->blkif->blk_protocol, protocol); |
4d05a28d KRW |
731 | |
732 | /* Map the shared frame, irq etc. */ | |
8b6bf747 | 733 | err = xen_blkif_map(be->blkif, ring_ref, evtchn); |
4d05a28d KRW |
734 | if (err) { |
735 | xenbus_dev_fatal(dev, err, "mapping ring-ref %lu port %u", | |
736 | ring_ref, evtchn); | |
737 | return err; | |
738 | } | |
739 | ||
740 | return 0; | |
741 | } | |
742 | ||
743 | ||
744 | /* ** Driver Registration ** */ | |
745 | ||
746 | ||
8b6bf747 | 747 | static const struct xenbus_device_id xen_blkbk_ids[] = { |
4d05a28d KRW |
748 | { "vbd" }, |
749 | { "" } | |
750 | }; | |
751 | ||
752 | ||
8b6bf747 | 753 | static struct xenbus_driver xen_blkbk = { |
4d05a28d KRW |
754 | .name = "vbd", |
755 | .owner = THIS_MODULE, | |
8b6bf747 KRW |
756 | .ids = xen_blkbk_ids, |
757 | .probe = xen_blkbk_probe, | |
758 | .remove = xen_blkbk_remove, | |
4d05a28d KRW |
759 | .otherend_changed = frontend_changed |
760 | }; | |
761 | ||
762 | ||
8b6bf747 | 763 | int xen_blkif_xenbus_init(void) |
4d05a28d | 764 | { |
8b6bf747 | 765 | return xenbus_register_backend(&xen_blkbk); |
4d05a28d | 766 | } |