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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 | ||
24 | #undef DPRINTK | |
25 | #define DPRINTK(fmt, args...) \ | |
26 | pr_debug("blkback/xenbus (%s:%d) " fmt ".\n", \ | |
d6091b21 | 27 | __func__, __LINE__, ##args) |
4d05a28d | 28 | |
d6091b21 | 29 | struct backend_info { |
4d05a28d | 30 | struct xenbus_device *dev; |
5489377c | 31 | struct blkif_st *blkif; |
4d05a28d KRW |
32 | struct xenbus_watch backend_watch; |
33 | unsigned major; | |
34 | unsigned minor; | |
35 | char *mode; | |
36 | }; | |
37 | ||
8b6bf747 | 38 | static struct kmem_cache *xen_blkif_cachep; |
4d05a28d KRW |
39 | static void connect(struct backend_info *); |
40 | static int connect_ring(struct backend_info *); | |
41 | static void backend_changed(struct xenbus_watch *, const char **, | |
42 | unsigned int); | |
43 | ||
8b6bf747 | 44 | struct xenbus_device *xen_blkbk_xenbus(struct backend_info *be) |
98e036a3 JF |
45 | { |
46 | return be->dev; | |
47 | } | |
48 | ||
5489377c | 49 | static int blkback_name(struct blkif_st *blkif, char *buf) |
4d05a28d KRW |
50 | { |
51 | char *devpath, *devname; | |
52 | struct xenbus_device *dev = blkif->be->dev; | |
53 | ||
54 | devpath = xenbus_read(XBT_NIL, dev->nodename, "dev", NULL); | |
55 | if (IS_ERR(devpath)) | |
56 | return PTR_ERR(devpath); | |
57 | ||
d6091b21 KRW |
58 | devname = strstr(devpath, "/dev/"); |
59 | if (devname != NULL) | |
4d05a28d KRW |
60 | devname += strlen("/dev/"); |
61 | else | |
62 | devname = devpath; | |
63 | ||
64 | snprintf(buf, TASK_COMM_LEN, "blkback.%d.%s", blkif->domid, devname); | |
65 | kfree(devpath); | |
66 | ||
67 | return 0; | |
68 | } | |
69 | ||
8b6bf747 | 70 | static void xen_update_blkif_status(struct blkif_st *blkif) |
4d05a28d KRW |
71 | { |
72 | int err; | |
73 | char name[TASK_COMM_LEN]; | |
74 | ||
75 | /* Not ready to connect? */ | |
76 | if (!blkif->irq || !blkif->vbd.bdev) | |
77 | return; | |
78 | ||
79 | /* Already connected? */ | |
80 | if (blkif->be->dev->state == XenbusStateConnected) | |
81 | return; | |
82 | ||
83 | /* Attempt to connect: exit if we fail to. */ | |
84 | connect(blkif->be); | |
85 | if (blkif->be->dev->state != XenbusStateConnected) | |
86 | return; | |
87 | ||
88 | err = blkback_name(blkif, name); | |
89 | if (err) { | |
90 | xenbus_dev_error(blkif->be->dev, err, "get blkback dev name"); | |
91 | return; | |
92 | } | |
93 | ||
cbf46290 CL |
94 | err = filemap_write_and_wait(blkif->vbd.bdev->bd_inode->i_mapping); |
95 | if (err) { | |
96 | xenbus_dev_error(blkif->be->dev, err, "block flush"); | |
97 | return; | |
98 | } | |
99 | invalidate_inode_pages2(blkif->vbd.bdev->bd_inode->i_mapping); | |
100 | ||
8b6bf747 | 101 | blkif->xenblkd = kthread_run(xen_blkif_schedule, blkif, name); |
4d05a28d KRW |
102 | if (IS_ERR(blkif->xenblkd)) { |
103 | err = PTR_ERR(blkif->xenblkd); | |
104 | blkif->xenblkd = NULL; | |
105 | xenbus_dev_error(blkif->be->dev, err, "start xenblkd"); | |
106 | } | |
107 | } | |
108 | ||
8b6bf747 | 109 | static struct blkif_st *xen_blkif_alloc(domid_t domid) |
ee9ff853 KRW |
110 | { |
111 | struct blkif_st *blkif; | |
112 | ||
8b6bf747 | 113 | blkif = kmem_cache_alloc(xen_blkif_cachep, GFP_KERNEL); |
ee9ff853 KRW |
114 | if (!blkif) |
115 | return ERR_PTR(-ENOMEM); | |
116 | ||
117 | memset(blkif, 0, sizeof(*blkif)); | |
118 | blkif->domid = domid; | |
119 | spin_lock_init(&blkif->blk_ring_lock); | |
120 | atomic_set(&blkif->refcnt, 1); | |
121 | init_waitqueue_head(&blkif->wq); | |
122 | blkif->st_print = jiffies; | |
123 | init_waitqueue_head(&blkif->waiting_to_free); | |
124 | ||
125 | return blkif; | |
126 | } | |
127 | ||
128 | static int map_frontend_page(struct blkif_st *blkif, unsigned long shared_page) | |
129 | { | |
130 | struct gnttab_map_grant_ref op; | |
131 | ||
132 | gnttab_set_map_op(&op, (unsigned long)blkif->blk_ring_area->addr, | |
133 | GNTMAP_host_map, shared_page, blkif->domid); | |
134 | ||
135 | if (HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, &op, 1)) | |
136 | BUG(); | |
137 | ||
138 | if (op.status) { | |
139 | DPRINTK(" Grant table operation failure !\n"); | |
140 | return op.status; | |
141 | } | |
142 | ||
143 | blkif->shmem_ref = shared_page; | |
144 | blkif->shmem_handle = op.handle; | |
145 | ||
146 | return 0; | |
147 | } | |
148 | ||
149 | static void unmap_frontend_page(struct blkif_st *blkif) | |
150 | { | |
151 | struct gnttab_unmap_grant_ref op; | |
152 | ||
153 | gnttab_set_unmap_op(&op, (unsigned long)blkif->blk_ring_area->addr, | |
154 | GNTMAP_host_map, blkif->shmem_handle); | |
155 | ||
156 | if (HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, &op, 1)) | |
157 | BUG(); | |
158 | } | |
159 | ||
8b6bf747 KRW |
160 | static int xen_blkif_map(struct blkif_st *blkif, unsigned long shared_page, |
161 | unsigned int evtchn) | |
ee9ff853 KRW |
162 | { |
163 | int err; | |
164 | ||
165 | /* Already connected through? */ | |
166 | if (blkif->irq) | |
167 | return 0; | |
168 | ||
169 | blkif->blk_ring_area = alloc_vm_area(PAGE_SIZE); | |
170 | if (!blkif->blk_ring_area) | |
171 | return -ENOMEM; | |
172 | ||
173 | err = map_frontend_page(blkif, shared_page); | |
174 | if (err) { | |
175 | free_vm_area(blkif->blk_ring_area); | |
176 | return err; | |
177 | } | |
178 | ||
179 | switch (blkif->blk_protocol) { | |
180 | case BLKIF_PROTOCOL_NATIVE: | |
181 | { | |
182 | struct blkif_sring *sring; | |
183 | sring = (struct blkif_sring *)blkif->blk_ring_area->addr; | |
184 | BACK_RING_INIT(&blkif->blk_rings.native, sring, PAGE_SIZE); | |
185 | break; | |
186 | } | |
187 | case BLKIF_PROTOCOL_X86_32: | |
188 | { | |
189 | struct blkif_x86_32_sring *sring_x86_32; | |
190 | sring_x86_32 = (struct blkif_x86_32_sring *)blkif->blk_ring_area->addr; | |
191 | BACK_RING_INIT(&blkif->blk_rings.x86_32, sring_x86_32, PAGE_SIZE); | |
192 | break; | |
193 | } | |
194 | case BLKIF_PROTOCOL_X86_64: | |
195 | { | |
196 | struct blkif_x86_64_sring *sring_x86_64; | |
197 | sring_x86_64 = (struct blkif_x86_64_sring *)blkif->blk_ring_area->addr; | |
198 | BACK_RING_INIT(&blkif->blk_rings.x86_64, sring_x86_64, PAGE_SIZE); | |
199 | break; | |
200 | } | |
201 | default: | |
202 | BUG(); | |
203 | } | |
204 | ||
8b6bf747 KRW |
205 | err = bind_interdomain_evtchn_to_irqhandler(blkif->domid, evtchn, |
206 | xen_blkif_be_int, 0, | |
207 | "blkif-backend", blkif); | |
ee9ff853 KRW |
208 | if (err < 0) { |
209 | unmap_frontend_page(blkif); | |
210 | free_vm_area(blkif->blk_ring_area); | |
211 | blkif->blk_rings.common.sring = NULL; | |
212 | return err; | |
213 | } | |
214 | blkif->irq = err; | |
215 | ||
216 | return 0; | |
217 | } | |
218 | ||
8b6bf747 | 219 | static void xen_blkif_disconnect(struct blkif_st *blkif) |
ee9ff853 KRW |
220 | { |
221 | if (blkif->xenblkd) { | |
222 | kthread_stop(blkif->xenblkd); | |
223 | blkif->xenblkd = NULL; | |
224 | } | |
225 | ||
226 | atomic_dec(&blkif->refcnt); | |
227 | wait_event(blkif->waiting_to_free, atomic_read(&blkif->refcnt) == 0); | |
228 | atomic_inc(&blkif->refcnt); | |
229 | ||
230 | if (blkif->irq) { | |
231 | unbind_from_irqhandler(blkif->irq, blkif); | |
232 | blkif->irq = 0; | |
233 | } | |
234 | ||
235 | if (blkif->blk_rings.common.sring) { | |
236 | unmap_frontend_page(blkif); | |
237 | free_vm_area(blkif->blk_ring_area); | |
238 | blkif->blk_rings.common.sring = NULL; | |
239 | } | |
240 | } | |
241 | ||
8b6bf747 | 242 | void xen_blkif_free(struct blkif_st *blkif) |
ee9ff853 KRW |
243 | { |
244 | if (!atomic_dec_and_test(&blkif->refcnt)) | |
245 | BUG(); | |
8b6bf747 | 246 | kmem_cache_free(xen_blkif_cachep, blkif); |
ee9ff853 KRW |
247 | } |
248 | ||
8b6bf747 | 249 | int __init xen_blkif_interface_init(void) |
ee9ff853 | 250 | { |
8b6bf747 KRW |
251 | xen_blkif_cachep = kmem_cache_create("blkif_cache", |
252 | sizeof(struct blkif_st), | |
253 | 0, 0, NULL); | |
254 | if (!xen_blkif_cachep) | |
ee9ff853 KRW |
255 | return -ENOMEM; |
256 | ||
257 | return 0; | |
258 | } | |
4d05a28d | 259 | |
a1397fa3 | 260 | /* |
4d05a28d KRW |
261 | * sysfs interface for VBD I/O requests |
262 | */ | |
263 | ||
264 | #define VBD_SHOW(name, format, args...) \ | |
265 | static ssize_t show_##name(struct device *_dev, \ | |
266 | struct device_attribute *attr, \ | |
267 | char *buf) \ | |
268 | { \ | |
269 | struct xenbus_device *dev = to_xenbus_device(_dev); \ | |
5cf6e4f6 | 270 | struct backend_info *be = dev_get_drvdata(&dev->dev); \ |
4d05a28d KRW |
271 | \ |
272 | return sprintf(buf, format, ##args); \ | |
273 | } \ | |
274 | static DEVICE_ATTR(name, S_IRUGO, show_##name, NULL) | |
275 | ||
276 | VBD_SHOW(oo_req, "%d\n", be->blkif->st_oo_req); | |
277 | VBD_SHOW(rd_req, "%d\n", be->blkif->st_rd_req); | |
278 | VBD_SHOW(wr_req, "%d\n", be->blkif->st_wr_req); | |
24f567f9 | 279 | VBD_SHOW(f_req, "%d\n", be->blkif->st_f_req); |
4d05a28d KRW |
280 | VBD_SHOW(rd_sect, "%d\n", be->blkif->st_rd_sect); |
281 | VBD_SHOW(wr_sect, "%d\n", be->blkif->st_wr_sect); | |
282 | ||
283 | static struct attribute *vbdstat_attrs[] = { | |
284 | &dev_attr_oo_req.attr, | |
285 | &dev_attr_rd_req.attr, | |
286 | &dev_attr_wr_req.attr, | |
24f567f9 | 287 | &dev_attr_f_req.attr, |
4d05a28d KRW |
288 | &dev_attr_rd_sect.attr, |
289 | &dev_attr_wr_sect.attr, | |
290 | NULL | |
291 | }; | |
292 | ||
293 | static struct attribute_group vbdstat_group = { | |
294 | .name = "statistics", | |
295 | .attrs = vbdstat_attrs, | |
296 | }; | |
297 | ||
298 | VBD_SHOW(physical_device, "%x:%x\n", be->major, be->minor); | |
299 | VBD_SHOW(mode, "%s\n", be->mode); | |
300 | ||
301 | int xenvbd_sysfs_addif(struct xenbus_device *dev) | |
302 | { | |
303 | int error; | |
304 | ||
305 | error = device_create_file(&dev->dev, &dev_attr_physical_device); | |
d6091b21 | 306 | if (error) |
4d05a28d KRW |
307 | goto fail1; |
308 | ||
309 | error = device_create_file(&dev->dev, &dev_attr_mode); | |
310 | if (error) | |
311 | goto fail2; | |
312 | ||
313 | error = sysfs_create_group(&dev->dev.kobj, &vbdstat_group); | |
314 | if (error) | |
315 | goto fail3; | |
316 | ||
317 | return 0; | |
318 | ||
319 | fail3: sysfs_remove_group(&dev->dev.kobj, &vbdstat_group); | |
320 | fail2: device_remove_file(&dev->dev, &dev_attr_mode); | |
321 | fail1: device_remove_file(&dev->dev, &dev_attr_physical_device); | |
322 | return error; | |
323 | } | |
324 | ||
325 | void xenvbd_sysfs_delif(struct xenbus_device *dev) | |
326 | { | |
327 | sysfs_remove_group(&dev->dev.kobj, &vbdstat_group); | |
328 | device_remove_file(&dev->dev, &dev_attr_mode); | |
329 | device_remove_file(&dev->dev, &dev_attr_physical_device); | |
330 | } | |
331 | ||
42c7841d KRW |
332 | |
333 | static void vbd_free(struct vbd *vbd) | |
334 | { | |
335 | if (vbd->bdev) | |
336 | blkdev_put(vbd->bdev, vbd->readonly ? FMODE_READ : FMODE_WRITE); | |
337 | vbd->bdev = NULL; | |
338 | } | |
339 | ||
340 | static int vbd_create(struct blkif_st *blkif, blkif_vdev_t handle, | |
341 | unsigned major, unsigned minor, int readonly, | |
342 | int cdrom) | |
343 | { | |
344 | struct vbd *vbd; | |
345 | struct block_device *bdev; | |
24f567f9 | 346 | struct request_queue *q; |
42c7841d KRW |
347 | |
348 | vbd = &blkif->vbd; | |
349 | vbd->handle = handle; | |
350 | vbd->readonly = readonly; | |
351 | vbd->type = 0; | |
352 | ||
353 | vbd->pdevice = MKDEV(major, minor); | |
354 | ||
355 | bdev = blkdev_get_by_dev(vbd->pdevice, vbd->readonly ? | |
356 | FMODE_READ : FMODE_WRITE, NULL); | |
357 | ||
358 | if (IS_ERR(bdev)) { | |
359 | DPRINTK("vbd_creat: device %08x could not be opened.\n", | |
360 | vbd->pdevice); | |
361 | return -ENOENT; | |
362 | } | |
363 | ||
364 | vbd->bdev = bdev; | |
365 | vbd->size = vbd_sz(vbd); | |
366 | ||
367 | if (vbd->bdev->bd_disk == NULL) { | |
368 | DPRINTK("vbd_creat: device %08x doesn't exist.\n", | |
369 | vbd->pdevice); | |
370 | vbd_free(vbd); | |
371 | return -ENOENT; | |
372 | } | |
373 | ||
374 | if (vbd->bdev->bd_disk->flags & GENHD_FL_CD || cdrom) | |
375 | vbd->type |= VDISK_CDROM; | |
376 | if (vbd->bdev->bd_disk->flags & GENHD_FL_REMOVABLE) | |
377 | vbd->type |= VDISK_REMOVABLE; | |
378 | ||
24f567f9 KRW |
379 | q = bdev_get_queue(bdev); |
380 | if (q && q->flush_flags) | |
381 | vbd->flush_support = true; | |
382 | ||
42c7841d KRW |
383 | DPRINTK("Successful creation of handle=%04x (dom=%u)\n", |
384 | handle, blkif->domid); | |
385 | return 0; | |
386 | } | |
8b6bf747 | 387 | static int xen_blkbk_remove(struct xenbus_device *dev) |
4d05a28d | 388 | { |
5cf6e4f6 | 389 | struct backend_info *be = dev_get_drvdata(&dev->dev); |
4d05a28d KRW |
390 | |
391 | DPRINTK(""); | |
392 | ||
393 | if (be->major || be->minor) | |
394 | xenvbd_sysfs_delif(dev); | |
395 | ||
396 | if (be->backend_watch.node) { | |
397 | unregister_xenbus_watch(&be->backend_watch); | |
398 | kfree(be->backend_watch.node); | |
399 | be->backend_watch.node = NULL; | |
400 | } | |
401 | ||
402 | if (be->blkif) { | |
8b6bf747 | 403 | xen_blkif_disconnect(be->blkif); |
4d05a28d | 404 | vbd_free(&be->blkif->vbd); |
8b6bf747 | 405 | xen_blkif_free(be->blkif); |
4d05a28d KRW |
406 | be->blkif = NULL; |
407 | } | |
408 | ||
409 | kfree(be); | |
5cf6e4f6 | 410 | dev_set_drvdata(&dev->dev, NULL); |
4d05a28d KRW |
411 | return 0; |
412 | } | |
413 | ||
24f567f9 KRW |
414 | int xen_blkbk_flush_diskcache(struct xenbus_transaction xbt, |
415 | struct backend_info *be, int state) | |
4d05a28d KRW |
416 | { |
417 | struct xenbus_device *dev = be->dev; | |
418 | int err; | |
419 | ||
24f567f9 | 420 | err = xenbus_printf(xbt, dev->nodename, "feature-flush-cache", |
4d05a28d KRW |
421 | "%d", state); |
422 | if (err) | |
24f567f9 | 423 | xenbus_dev_fatal(dev, err, "writing feature-flush-cache"); |
4d05a28d KRW |
424 | |
425 | return err; | |
426 | } | |
427 | ||
428 | /** | |
429 | * Entry point to this code when a new device is created. Allocate the basic | |
430 | * structures, and watch the store waiting for the hotplug scripts to tell us | |
431 | * the device's physical major and minor numbers. Switch to InitWait. | |
432 | */ | |
8b6bf747 KRW |
433 | static int xen_blkbk_probe(struct xenbus_device *dev, |
434 | const struct xenbus_device_id *id) | |
4d05a28d KRW |
435 | { |
436 | int err; | |
437 | struct backend_info *be = kzalloc(sizeof(struct backend_info), | |
438 | GFP_KERNEL); | |
439 | if (!be) { | |
440 | xenbus_dev_fatal(dev, -ENOMEM, | |
441 | "allocating backend structure"); | |
442 | return -ENOMEM; | |
443 | } | |
444 | be->dev = dev; | |
5cf6e4f6 | 445 | dev_set_drvdata(&dev->dev, be); |
4d05a28d | 446 | |
8b6bf747 | 447 | be->blkif = xen_blkif_alloc(dev->otherend_id); |
4d05a28d KRW |
448 | if (IS_ERR(be->blkif)) { |
449 | err = PTR_ERR(be->blkif); | |
450 | be->blkif = NULL; | |
451 | xenbus_dev_fatal(dev, err, "creating block interface"); | |
452 | goto fail; | |
453 | } | |
454 | ||
455 | /* setup back pointer */ | |
456 | be->blkif->be = be; | |
457 | ||
88122933 JF |
458 | err = xenbus_watch_pathfmt(dev, &be->backend_watch, backend_changed, |
459 | "%s/%s", dev->nodename, "physical-device"); | |
4d05a28d KRW |
460 | if (err) |
461 | goto fail; | |
462 | ||
463 | err = xenbus_switch_state(dev, XenbusStateInitWait); | |
464 | if (err) | |
465 | goto fail; | |
466 | ||
467 | return 0; | |
468 | ||
469 | fail: | |
470 | DPRINTK("failed"); | |
8b6bf747 | 471 | xen_blkbk_remove(dev); |
4d05a28d KRW |
472 | return err; |
473 | } | |
474 | ||
475 | ||
476 | /** | |
477 | * Callback received when the hotplug scripts have placed the physical-device | |
478 | * node. Read it and the mode node, and create a vbd. If the frontend is | |
479 | * ready, connect. | |
480 | */ | |
481 | static void backend_changed(struct xenbus_watch *watch, | |
482 | const char **vec, unsigned int len) | |
483 | { | |
484 | int err; | |
485 | unsigned major; | |
486 | unsigned minor; | |
487 | struct backend_info *be | |
488 | = container_of(watch, struct backend_info, backend_watch); | |
489 | struct xenbus_device *dev = be->dev; | |
490 | int cdrom = 0; | |
491 | char *device_type; | |
492 | ||
493 | DPRINTK(""); | |
494 | ||
495 | err = xenbus_scanf(XBT_NIL, dev->nodename, "physical-device", "%x:%x", | |
496 | &major, &minor); | |
497 | if (XENBUS_EXIST_ERR(err)) { | |
498 | /* Since this watch will fire once immediately after it is | |
499 | registered, we expect this. Ignore it, and wait for the | |
500 | hotplug scripts. */ | |
501 | return; | |
502 | } | |
503 | if (err != 2) { | |
504 | xenbus_dev_fatal(dev, err, "reading physical-device"); | |
505 | return; | |
506 | } | |
507 | ||
508 | if ((be->major || be->minor) && | |
509 | ((be->major != major) || (be->minor != minor))) { | |
510 | printk(KERN_WARNING | |
511 | "blkback: changing physical device (from %x:%x to " | |
512 | "%x:%x) not supported.\n", be->major, be->minor, | |
513 | major, minor); | |
514 | return; | |
515 | } | |
516 | ||
517 | be->mode = xenbus_read(XBT_NIL, dev->nodename, "mode", NULL); | |
518 | if (IS_ERR(be->mode)) { | |
519 | err = PTR_ERR(be->mode); | |
520 | be->mode = NULL; | |
521 | xenbus_dev_fatal(dev, err, "reading mode"); | |
522 | return; | |
523 | } | |
524 | ||
525 | device_type = xenbus_read(XBT_NIL, dev->otherend, "device-type", NULL); | |
526 | if (!IS_ERR(device_type)) { | |
527 | cdrom = strcmp(device_type, "cdrom") == 0; | |
528 | kfree(device_type); | |
529 | } | |
530 | ||
531 | if (be->major == 0 && be->minor == 0) { | |
532 | /* Front end dir is a number, which is used as the handle. */ | |
533 | ||
534 | char *p = strrchr(dev->otherend, '/') + 1; | |
d6091b21 KRW |
535 | long handle; |
536 | err = strict_strtoul(p, 0, &handle); | |
537 | if (err) | |
538 | return; | |
4d05a28d KRW |
539 | |
540 | be->major = major; | |
541 | be->minor = minor; | |
542 | ||
543 | err = vbd_create(be->blkif, handle, major, minor, | |
544 | (NULL == strchr(be->mode, 'w')), cdrom); | |
545 | if (err) { | |
546 | be->major = be->minor = 0; | |
547 | xenbus_dev_fatal(dev, err, "creating vbd structure"); | |
548 | return; | |
549 | } | |
550 | ||
551 | err = xenvbd_sysfs_addif(dev); | |
552 | if (err) { | |
553 | vbd_free(&be->blkif->vbd); | |
554 | be->major = be->minor = 0; | |
555 | xenbus_dev_fatal(dev, err, "creating sysfs entries"); | |
556 | return; | |
557 | } | |
558 | ||
559 | /* We're potentially connected now */ | |
8b6bf747 | 560 | xen_update_blkif_status(be->blkif); |
4d05a28d KRW |
561 | } |
562 | } | |
563 | ||
564 | ||
565 | /** | |
566 | * Callback received when the frontend's state changes. | |
567 | */ | |
568 | static void frontend_changed(struct xenbus_device *dev, | |
569 | enum xenbus_state frontend_state) | |
570 | { | |
5cf6e4f6 | 571 | struct backend_info *be = dev_get_drvdata(&dev->dev); |
4d05a28d KRW |
572 | int err; |
573 | ||
574 | DPRINTK("%s", xenbus_strstate(frontend_state)); | |
575 | ||
576 | switch (frontend_state) { | |
577 | case XenbusStateInitialising: | |
578 | if (dev->state == XenbusStateClosed) { | |
579 | printk(KERN_INFO "%s: %s: prepare for reconnect\n", | |
d6091b21 | 580 | __func__, dev->nodename); |
4d05a28d KRW |
581 | xenbus_switch_state(dev, XenbusStateInitWait); |
582 | } | |
583 | break; | |
584 | ||
585 | case XenbusStateInitialised: | |
586 | case XenbusStateConnected: | |
587 | /* Ensure we connect even when two watches fire in | |
588 | close successsion and we miss the intermediate value | |
589 | of frontend_state. */ | |
590 | if (dev->state == XenbusStateConnected) | |
591 | break; | |
592 | ||
313d7b00 KF |
593 | /* Enforce precondition before potential leak point. |
594 | * blkif_disconnect() is idempotent. | |
595 | */ | |
8b6bf747 | 596 | xen_blkif_disconnect(be->blkif); |
313d7b00 | 597 | |
4d05a28d KRW |
598 | err = connect_ring(be); |
599 | if (err) | |
600 | break; | |
8b6bf747 | 601 | xen_update_blkif_status(be->blkif); |
4d05a28d KRW |
602 | break; |
603 | ||
604 | case XenbusStateClosing: | |
8b6bf747 | 605 | xen_blkif_disconnect(be->blkif); |
4d05a28d KRW |
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: | |
313d7b00 | 615 | /* implies blkif_disconnect() via blkback_remove() */ |
4d05a28d KRW |
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 | ||
24f567f9 | 650 | err = xen_blkbk_flush_diskcache(xbt, be, be->blkif->vbd.flush_support); |
4d05a28d KRW |
651 | if (err) |
652 | goto abort; | |
653 | ||
654 | err = xenbus_printf(xbt, dev->nodename, "sectors", "%llu", | |
42c7841d | 655 | (unsigned long long)vbd_sz(&be->blkif->vbd)); |
4d05a28d KRW |
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", | |
42c7841d KRW |
664 | be->blkif->vbd.type | |
665 | (be->blkif->vbd.readonly ? VDISK_READONLY : 0)); | |
4d05a28d KRW |
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", | |
42c7841d KRW |
672 | (unsigned long) |
673 | bdev_logical_block_size(be->blkif->vbd.bdev)); | |
4d05a28d KRW |
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 | ||
d6091b21 KRW |
707 | err = xenbus_gather(XBT_NIL, dev->otherend, "ring-ref", "%lu", |
708 | &ring_ref, "event-channel", "%u", &evtchn, NULL); | |
4d05a28d KRW |
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 | printk(KERN_INFO | |
732 | "blkback: ring-ref %ld, event-channel %d, protocol %d (%s)\n", | |
733 | ring_ref, evtchn, be->blkif->blk_protocol, protocol); | |
734 | ||
735 | /* Map the shared frame, irq etc. */ | |
8b6bf747 | 736 | err = xen_blkif_map(be->blkif, ring_ref, evtchn); |
4d05a28d KRW |
737 | if (err) { |
738 | xenbus_dev_fatal(dev, err, "mapping ring-ref %lu port %u", | |
739 | ring_ref, evtchn); | |
740 | return err; | |
741 | } | |
742 | ||
743 | return 0; | |
744 | } | |
745 | ||
746 | ||
747 | /* ** Driver Registration ** */ | |
748 | ||
749 | ||
8b6bf747 | 750 | static const struct xenbus_device_id xen_blkbk_ids[] = { |
4d05a28d KRW |
751 | { "vbd" }, |
752 | { "" } | |
753 | }; | |
754 | ||
755 | ||
8b6bf747 | 756 | static struct xenbus_driver xen_blkbk = { |
4d05a28d KRW |
757 | .name = "vbd", |
758 | .owner = THIS_MODULE, | |
8b6bf747 KRW |
759 | .ids = xen_blkbk_ids, |
760 | .probe = xen_blkbk_probe, | |
761 | .remove = xen_blkbk_remove, | |
4d05a28d KRW |
762 | .otherend_changed = frontend_changed |
763 | }; | |
764 | ||
765 | ||
8b6bf747 | 766 | int xen_blkif_xenbus_init(void) |
4d05a28d | 767 | { |
8b6bf747 | 768 | return xenbus_register_backend(&xen_blkbk); |
4d05a28d | 769 | } |