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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 | 25 | struct xenbus_device *dev; |
51854322 | 26 | struct xen_blkif *blkif; |
01f37f2d KRW |
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 | ||
30fd1502 | 44 | static int blkback_name(struct xen_blkif *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 | ||
30fd1502 | 65 | static void xen_update_blkif_status(struct xen_blkif *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"); | |
3f3aad5e | 101 | return; |
4d05a28d KRW |
102 | } |
103 | } | |
104 | ||
30fd1502 | 105 | static struct xen_blkif *xen_blkif_alloc(domid_t domid) |
ee9ff853 | 106 | { |
30fd1502 | 107 | struct xen_blkif *blkif; |
bf0720c4 | 108 | int i; |
ee9ff853 | 109 | |
402b27f9 RPM |
110 | BUILD_BUG_ON(MAX_INDIRECT_PAGES > BLKIF_MAX_INDIRECT_PAGES_PER_REQUEST); |
111 | ||
654dbef2 | 112 | blkif = kmem_cache_zalloc(xen_blkif_cachep, GFP_KERNEL); |
ee9ff853 KRW |
113 | if (!blkif) |
114 | return ERR_PTR(-ENOMEM); | |
115 | ||
ee9ff853 KRW |
116 | blkif->domid = domid; |
117 | spin_lock_init(&blkif->blk_ring_lock); | |
118 | atomic_set(&blkif->refcnt, 1); | |
119 | init_waitqueue_head(&blkif->wq); | |
29bde093 KRW |
120 | init_completion(&blkif->drain_complete); |
121 | atomic_set(&blkif->drain, 0); | |
ee9ff853 KRW |
122 | blkif->st_print = jiffies; |
123 | init_waitqueue_head(&blkif->waiting_to_free); | |
0a8704a5 | 124 | blkif->persistent_gnts.rb_node = NULL; |
c6cc142d RPM |
125 | spin_lock_init(&blkif->free_pages_lock); |
126 | INIT_LIST_HEAD(&blkif->free_pages); | |
127 | blkif->free_pages_num = 0; | |
3f3aad5e | 128 | atomic_set(&blkif->persistent_gnt_in_use, 0); |
ee9ff853 | 129 | |
bf0720c4 RPM |
130 | blkif->pending_reqs = kcalloc(XEN_BLKIF_REQS, |
131 | sizeof(blkif->pending_reqs[0]), | |
132 | GFP_KERNEL); | |
133 | if (!blkif->pending_reqs) { | |
134 | kmem_cache_free(xen_blkif_cachep, blkif); | |
135 | return ERR_PTR(-ENOMEM); | |
136 | } | |
137 | INIT_LIST_HEAD(&blkif->pending_free); | |
138 | spin_lock_init(&blkif->pending_free_lock); | |
139 | init_waitqueue_head(&blkif->pending_free_wq); | |
140 | ||
141 | for (i = 0; i < XEN_BLKIF_REQS; i++) | |
142 | list_add_tail(&blkif->pending_reqs[i].free_list, | |
143 | &blkif->pending_free); | |
144 | ||
ee9ff853 KRW |
145 | return blkif; |
146 | } | |
147 | ||
30fd1502 | 148 | static int xen_blkif_map(struct xen_blkif *blkif, unsigned long shared_page, |
8b6bf747 | 149 | unsigned int evtchn) |
ee9ff853 KRW |
150 | { |
151 | int err; | |
152 | ||
153 | /* Already connected through? */ | |
154 | if (blkif->irq) | |
155 | return 0; | |
156 | ||
2d073846 DV |
157 | err = xenbus_map_ring_valloc(blkif->be->dev, shared_page, &blkif->blk_ring); |
158 | if (err < 0) | |
ee9ff853 | 159 | return err; |
ee9ff853 KRW |
160 | |
161 | switch (blkif->blk_protocol) { | |
162 | case BLKIF_PROTOCOL_NATIVE: | |
163 | { | |
164 | struct blkif_sring *sring; | |
2d073846 | 165 | sring = (struct blkif_sring *)blkif->blk_ring; |
ee9ff853 KRW |
166 | BACK_RING_INIT(&blkif->blk_rings.native, sring, PAGE_SIZE); |
167 | break; | |
168 | } | |
169 | case BLKIF_PROTOCOL_X86_32: | |
170 | { | |
171 | struct blkif_x86_32_sring *sring_x86_32; | |
2d073846 | 172 | sring_x86_32 = (struct blkif_x86_32_sring *)blkif->blk_ring; |
ee9ff853 KRW |
173 | BACK_RING_INIT(&blkif->blk_rings.x86_32, sring_x86_32, PAGE_SIZE); |
174 | break; | |
175 | } | |
176 | case BLKIF_PROTOCOL_X86_64: | |
177 | { | |
178 | struct blkif_x86_64_sring *sring_x86_64; | |
2d073846 | 179 | sring_x86_64 = (struct blkif_x86_64_sring *)blkif->blk_ring; |
ee9ff853 KRW |
180 | BACK_RING_INIT(&blkif->blk_rings.x86_64, sring_x86_64, PAGE_SIZE); |
181 | break; | |
182 | } | |
183 | default: | |
184 | BUG(); | |
185 | } | |
186 | ||
8b6bf747 KRW |
187 | err = bind_interdomain_evtchn_to_irqhandler(blkif->domid, evtchn, |
188 | xen_blkif_be_int, 0, | |
189 | "blkif-backend", blkif); | |
ee9ff853 | 190 | if (err < 0) { |
2d073846 | 191 | xenbus_unmap_ring_vfree(blkif->be->dev, blkif->blk_ring); |
ee9ff853 KRW |
192 | blkif->blk_rings.common.sring = NULL; |
193 | return err; | |
194 | } | |
195 | blkif->irq = err; | |
196 | ||
197 | return 0; | |
198 | } | |
199 | ||
30fd1502 | 200 | static void xen_blkif_disconnect(struct xen_blkif *blkif) |
ee9ff853 KRW |
201 | { |
202 | if (blkif->xenblkd) { | |
203 | kthread_stop(blkif->xenblkd); | |
204 | blkif->xenblkd = NULL; | |
205 | } | |
206 | ||
207 | atomic_dec(&blkif->refcnt); | |
208 | wait_event(blkif->waiting_to_free, atomic_read(&blkif->refcnt) == 0); | |
209 | atomic_inc(&blkif->refcnt); | |
210 | ||
211 | if (blkif->irq) { | |
212 | unbind_from_irqhandler(blkif->irq, blkif); | |
213 | blkif->irq = 0; | |
214 | } | |
215 | ||
216 | if (blkif->blk_rings.common.sring) { | |
2d073846 | 217 | xenbus_unmap_ring_vfree(blkif->be->dev, blkif->blk_ring); |
ee9ff853 KRW |
218 | blkif->blk_rings.common.sring = NULL; |
219 | } | |
220 | } | |
221 | ||
2911758f | 222 | static void xen_blkif_free(struct xen_blkif *blkif) |
ee9ff853 | 223 | { |
bf0720c4 RPM |
224 | struct pending_req *req; |
225 | int i = 0; | |
226 | ||
ee9ff853 KRW |
227 | if (!atomic_dec_and_test(&blkif->refcnt)) |
228 | BUG(); | |
bf0720c4 RPM |
229 | |
230 | /* Check that there is no request in use */ | |
231 | list_for_each_entry(req, &blkif->pending_free, free_list) | |
232 | i++; | |
233 | BUG_ON(i != XEN_BLKIF_REQS); | |
234 | ||
235 | kfree(blkif->pending_reqs); | |
8b6bf747 | 236 | kmem_cache_free(xen_blkif_cachep, blkif); |
ee9ff853 KRW |
237 | } |
238 | ||
8b6bf747 | 239 | int __init xen_blkif_interface_init(void) |
ee9ff853 | 240 | { |
8b6bf747 | 241 | xen_blkif_cachep = kmem_cache_create("blkif_cache", |
30fd1502 | 242 | sizeof(struct xen_blkif), |
8b6bf747 KRW |
243 | 0, 0, NULL); |
244 | if (!xen_blkif_cachep) | |
ee9ff853 KRW |
245 | return -ENOMEM; |
246 | ||
247 | return 0; | |
248 | } | |
4d05a28d | 249 | |
a1397fa3 | 250 | /* |
4d05a28d KRW |
251 | * sysfs interface for VBD I/O requests |
252 | */ | |
253 | ||
254 | #define VBD_SHOW(name, format, args...) \ | |
255 | static ssize_t show_##name(struct device *_dev, \ | |
256 | struct device_attribute *attr, \ | |
257 | char *buf) \ | |
258 | { \ | |
259 | struct xenbus_device *dev = to_xenbus_device(_dev); \ | |
5cf6e4f6 | 260 | struct backend_info *be = dev_get_drvdata(&dev->dev); \ |
4d05a28d KRW |
261 | \ |
262 | return sprintf(buf, format, ##args); \ | |
263 | } \ | |
264 | static DEVICE_ATTR(name, S_IRUGO, show_##name, NULL) | |
265 | ||
986cacbd ZK |
266 | VBD_SHOW(oo_req, "%llu\n", be->blkif->st_oo_req); |
267 | VBD_SHOW(rd_req, "%llu\n", be->blkif->st_rd_req); | |
268 | VBD_SHOW(wr_req, "%llu\n", be->blkif->st_wr_req); | |
269 | VBD_SHOW(f_req, "%llu\n", be->blkif->st_f_req); | |
270 | VBD_SHOW(ds_req, "%llu\n", be->blkif->st_ds_req); | |
271 | VBD_SHOW(rd_sect, "%llu\n", be->blkif->st_rd_sect); | |
272 | VBD_SHOW(wr_sect, "%llu\n", be->blkif->st_wr_sect); | |
4d05a28d | 273 | |
3d814731 | 274 | static struct attribute *xen_vbdstat_attrs[] = { |
4d05a28d KRW |
275 | &dev_attr_oo_req.attr, |
276 | &dev_attr_rd_req.attr, | |
277 | &dev_attr_wr_req.attr, | |
24f567f9 | 278 | &dev_attr_f_req.attr, |
b3cb0d6a | 279 | &dev_attr_ds_req.attr, |
4d05a28d KRW |
280 | &dev_attr_rd_sect.attr, |
281 | &dev_attr_wr_sect.attr, | |
282 | NULL | |
283 | }; | |
284 | ||
3d814731 | 285 | static struct attribute_group xen_vbdstat_group = { |
4d05a28d | 286 | .name = "statistics", |
3d814731 | 287 | .attrs = xen_vbdstat_attrs, |
4d05a28d KRW |
288 | }; |
289 | ||
290 | VBD_SHOW(physical_device, "%x:%x\n", be->major, be->minor); | |
291 | VBD_SHOW(mode, "%s\n", be->mode); | |
292 | ||
2911758f | 293 | static int xenvbd_sysfs_addif(struct xenbus_device *dev) |
4d05a28d KRW |
294 | { |
295 | int error; | |
296 | ||
297 | error = device_create_file(&dev->dev, &dev_attr_physical_device); | |
d6091b21 | 298 | if (error) |
4d05a28d KRW |
299 | goto fail1; |
300 | ||
301 | error = device_create_file(&dev->dev, &dev_attr_mode); | |
302 | if (error) | |
303 | goto fail2; | |
304 | ||
3d814731 | 305 | error = sysfs_create_group(&dev->dev.kobj, &xen_vbdstat_group); |
4d05a28d KRW |
306 | if (error) |
307 | goto fail3; | |
308 | ||
309 | return 0; | |
310 | ||
3d814731 | 311 | fail3: sysfs_remove_group(&dev->dev.kobj, &xen_vbdstat_group); |
4d05a28d KRW |
312 | fail2: device_remove_file(&dev->dev, &dev_attr_mode); |
313 | fail1: device_remove_file(&dev->dev, &dev_attr_physical_device); | |
314 | return error; | |
315 | } | |
316 | ||
2911758f | 317 | static void xenvbd_sysfs_delif(struct xenbus_device *dev) |
4d05a28d | 318 | { |
3d814731 | 319 | sysfs_remove_group(&dev->dev.kobj, &xen_vbdstat_group); |
4d05a28d KRW |
320 | device_remove_file(&dev->dev, &dev_attr_mode); |
321 | device_remove_file(&dev->dev, &dev_attr_physical_device); | |
322 | } | |
323 | ||
42c7841d | 324 | |
3d814731 | 325 | static void xen_vbd_free(struct xen_vbd *vbd) |
42c7841d KRW |
326 | { |
327 | if (vbd->bdev) | |
328 | blkdev_put(vbd->bdev, vbd->readonly ? FMODE_READ : FMODE_WRITE); | |
329 | vbd->bdev = NULL; | |
330 | } | |
331 | ||
3d814731 KRW |
332 | static int xen_vbd_create(struct xen_blkif *blkif, blkif_vdev_t handle, |
333 | unsigned major, unsigned minor, int readonly, | |
334 | int cdrom) | |
42c7841d | 335 | { |
3d814731 | 336 | struct xen_vbd *vbd; |
42c7841d | 337 | struct block_device *bdev; |
24f567f9 | 338 | struct request_queue *q; |
42c7841d KRW |
339 | |
340 | vbd = &blkif->vbd; | |
341 | vbd->handle = handle; | |
342 | vbd->readonly = readonly; | |
343 | vbd->type = 0; | |
344 | ||
345 | vbd->pdevice = MKDEV(major, minor); | |
346 | ||
347 | bdev = blkdev_get_by_dev(vbd->pdevice, vbd->readonly ? | |
348 | FMODE_READ : FMODE_WRITE, NULL); | |
349 | ||
350 | if (IS_ERR(bdev)) { | |
3d814731 | 351 | DPRINTK("xen_vbd_create: device %08x could not be opened.\n", |
42c7841d KRW |
352 | vbd->pdevice); |
353 | return -ENOENT; | |
354 | } | |
355 | ||
356 | vbd->bdev = bdev; | |
42c7841d | 357 | if (vbd->bdev->bd_disk == NULL) { |
3d814731 | 358 | DPRINTK("xen_vbd_create: device %08x doesn't exist.\n", |
42c7841d | 359 | vbd->pdevice); |
3d814731 | 360 | xen_vbd_free(vbd); |
42c7841d KRW |
361 | return -ENOENT; |
362 | } | |
6464920a | 363 | vbd->size = vbd_sz(vbd); |
42c7841d KRW |
364 | |
365 | if (vbd->bdev->bd_disk->flags & GENHD_FL_CD || cdrom) | |
366 | vbd->type |= VDISK_CDROM; | |
367 | if (vbd->bdev->bd_disk->flags & GENHD_FL_REMOVABLE) | |
368 | vbd->type |= VDISK_REMOVABLE; | |
369 | ||
24f567f9 KRW |
370 | q = bdev_get_queue(bdev); |
371 | if (q && q->flush_flags) | |
372 | vbd->flush_support = true; | |
373 | ||
5ea42986 KRW |
374 | if (q && blk_queue_secdiscard(q)) |
375 | vbd->discard_secure = true; | |
376 | ||
42c7841d KRW |
377 | DPRINTK("Successful creation of handle=%04x (dom=%u)\n", |
378 | handle, blkif->domid); | |
379 | return 0; | |
380 | } | |
8b6bf747 | 381 | static int xen_blkbk_remove(struct xenbus_device *dev) |
4d05a28d | 382 | { |
5cf6e4f6 | 383 | struct backend_info *be = dev_get_drvdata(&dev->dev); |
4d05a28d KRW |
384 | |
385 | DPRINTK(""); | |
386 | ||
387 | if (be->major || be->minor) | |
388 | xenvbd_sysfs_delif(dev); | |
389 | ||
390 | if (be->backend_watch.node) { | |
391 | unregister_xenbus_watch(&be->backend_watch); | |
392 | kfree(be->backend_watch.node); | |
393 | be->backend_watch.node = NULL; | |
394 | } | |
395 | ||
396 | if (be->blkif) { | |
8b6bf747 | 397 | xen_blkif_disconnect(be->blkif); |
3d814731 | 398 | xen_vbd_free(&be->blkif->vbd); |
8b6bf747 | 399 | xen_blkif_free(be->blkif); |
4d05a28d KRW |
400 | be->blkif = NULL; |
401 | } | |
402 | ||
9d092603 | 403 | kfree(be->mode); |
4d05a28d | 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) | |
3389bb8b | 418 | dev_warn(&dev->dev, "writing feature-flush-cache (%d)", err); |
4d05a28d KRW |
419 | |
420 | return err; | |
421 | } | |
422 | ||
3389bb8b | 423 | static void xen_blkbk_discard(struct xenbus_transaction xbt, struct backend_info *be) |
b3cb0d6a LD |
424 | { |
425 | struct xenbus_device *dev = be->dev; | |
426 | struct xen_blkif *blkif = be->blkif; | |
b3cb0d6a LD |
427 | int err; |
428 | int state = 0; | |
4dae7670 KRW |
429 | struct block_device *bdev = be->blkif->vbd.bdev; |
430 | struct request_queue *q = bdev_get_queue(bdev); | |
431 | ||
432 | if (blk_queue_discard(q)) { | |
433 | err = xenbus_printf(xbt, dev->nodename, | |
434 | "discard-granularity", "%u", | |
435 | q->limits.discard_granularity); | |
436 | if (err) { | |
3389bb8b KRW |
437 | dev_warn(&dev->dev, "writing discard-granularity (%d)", err); |
438 | return; | |
4dae7670 KRW |
439 | } |
440 | err = xenbus_printf(xbt, dev->nodename, | |
441 | "discard-alignment", "%u", | |
442 | q->limits.discard_alignment); | |
443 | if (err) { | |
3389bb8b KRW |
444 | dev_warn(&dev->dev, "writing discard-alignment (%d)", err); |
445 | return; | |
b3cb0d6a | 446 | } |
4dae7670 KRW |
447 | state = 1; |
448 | /* Optional. */ | |
449 | err = xenbus_printf(xbt, dev->nodename, | |
450 | "discard-secure", "%d", | |
451 | blkif->vbd.discard_secure); | |
452 | if (err) { | |
a71e23d9 | 453 | dev_warn(&dev->dev, "writing discard-secure (%d)", err); |
3389bb8b | 454 | return; |
b3cb0d6a | 455 | } |
b3cb0d6a | 456 | } |
b3cb0d6a LD |
457 | err = xenbus_printf(xbt, dev->nodename, "feature-discard", |
458 | "%d", state); | |
459 | if (err) | |
3389bb8b | 460 | dev_warn(&dev->dev, "writing feature-discard (%d)", err); |
b3cb0d6a | 461 | } |
29bde093 KRW |
462 | int xen_blkbk_barrier(struct xenbus_transaction xbt, |
463 | struct backend_info *be, int state) | |
464 | { | |
465 | struct xenbus_device *dev = be->dev; | |
466 | int err; | |
467 | ||
468 | err = xenbus_printf(xbt, dev->nodename, "feature-barrier", | |
469 | "%d", state); | |
470 | if (err) | |
3389bb8b | 471 | dev_warn(&dev->dev, "writing feature-barrier (%d)", err); |
29bde093 KRW |
472 | |
473 | return err; | |
474 | } | |
b3cb0d6a | 475 | |
01f37f2d | 476 | /* |
4d05a28d KRW |
477 | * Entry point to this code when a new device is created. Allocate the basic |
478 | * structures, and watch the store waiting for the hotplug scripts to tell us | |
479 | * the device's physical major and minor numbers. Switch to InitWait. | |
480 | */ | |
8b6bf747 KRW |
481 | static int xen_blkbk_probe(struct xenbus_device *dev, |
482 | const struct xenbus_device_id *id) | |
4d05a28d KRW |
483 | { |
484 | int err; | |
485 | struct backend_info *be = kzalloc(sizeof(struct backend_info), | |
486 | GFP_KERNEL); | |
487 | if (!be) { | |
488 | xenbus_dev_fatal(dev, -ENOMEM, | |
489 | "allocating backend structure"); | |
490 | return -ENOMEM; | |
491 | } | |
492 | be->dev = dev; | |
5cf6e4f6 | 493 | dev_set_drvdata(&dev->dev, be); |
4d05a28d | 494 | |
8b6bf747 | 495 | be->blkif = xen_blkif_alloc(dev->otherend_id); |
4d05a28d KRW |
496 | if (IS_ERR(be->blkif)) { |
497 | err = PTR_ERR(be->blkif); | |
498 | be->blkif = NULL; | |
499 | xenbus_dev_fatal(dev, err, "creating block interface"); | |
500 | goto fail; | |
501 | } | |
502 | ||
503 | /* setup back pointer */ | |
504 | be->blkif->be = be; | |
505 | ||
88122933 JF |
506 | err = xenbus_watch_pathfmt(dev, &be->backend_watch, backend_changed, |
507 | "%s/%s", dev->nodename, "physical-device"); | |
4d05a28d KRW |
508 | if (err) |
509 | goto fail; | |
510 | ||
511 | err = xenbus_switch_state(dev, XenbusStateInitWait); | |
512 | if (err) | |
513 | goto fail; | |
514 | ||
515 | return 0; | |
516 | ||
517 | fail: | |
518 | DPRINTK("failed"); | |
8b6bf747 | 519 | xen_blkbk_remove(dev); |
4d05a28d KRW |
520 | return err; |
521 | } | |
522 | ||
523 | ||
01f37f2d | 524 | /* |
4d05a28d KRW |
525 | * Callback received when the hotplug scripts have placed the physical-device |
526 | * node. Read it and the mode node, and create a vbd. If the frontend is | |
527 | * ready, connect. | |
528 | */ | |
529 | static void backend_changed(struct xenbus_watch *watch, | |
530 | const char **vec, unsigned int len) | |
531 | { | |
532 | int err; | |
533 | unsigned major; | |
534 | unsigned minor; | |
535 | struct backend_info *be | |
536 | = container_of(watch, struct backend_info, backend_watch); | |
537 | struct xenbus_device *dev = be->dev; | |
538 | int cdrom = 0; | |
9d092603 | 539 | unsigned long handle; |
4d05a28d KRW |
540 | char *device_type; |
541 | ||
542 | DPRINTK(""); | |
543 | ||
544 | err = xenbus_scanf(XBT_NIL, dev->nodename, "physical-device", "%x:%x", | |
545 | &major, &minor); | |
546 | if (XENBUS_EXIST_ERR(err)) { | |
01f37f2d KRW |
547 | /* |
548 | * Since this watch will fire once immediately after it is | |
549 | * registered, we expect this. Ignore it, and wait for the | |
550 | * hotplug scripts. | |
551 | */ | |
4d05a28d KRW |
552 | return; |
553 | } | |
554 | if (err != 2) { | |
555 | xenbus_dev_fatal(dev, err, "reading physical-device"); | |
556 | return; | |
557 | } | |
558 | ||
9d092603 JB |
559 | if (be->major | be->minor) { |
560 | if (be->major != major || be->minor != minor) | |
561 | pr_warn(DRV_PFX "changing physical device (from %x:%x to %x:%x) not supported.\n", | |
562 | be->major, be->minor, major, minor); | |
4d05a28d KRW |
563 | return; |
564 | } | |
565 | ||
566 | be->mode = xenbus_read(XBT_NIL, dev->nodename, "mode", NULL); | |
567 | if (IS_ERR(be->mode)) { | |
568 | err = PTR_ERR(be->mode); | |
569 | be->mode = NULL; | |
570 | xenbus_dev_fatal(dev, err, "reading mode"); | |
571 | return; | |
572 | } | |
573 | ||
574 | device_type = xenbus_read(XBT_NIL, dev->otherend, "device-type", NULL); | |
575 | if (!IS_ERR(device_type)) { | |
576 | cdrom = strcmp(device_type, "cdrom") == 0; | |
577 | kfree(device_type); | |
578 | } | |
579 | ||
9d092603 JB |
580 | /* Front end dir is a number, which is used as the handle. */ |
581 | err = strict_strtoul(strrchr(dev->otherend, '/') + 1, 0, &handle); | |
582 | if (err) | |
583 | return; | |
4d05a28d | 584 | |
9d092603 JB |
585 | be->major = major; |
586 | be->minor = minor; | |
4d05a28d | 587 | |
9d092603 JB |
588 | err = xen_vbd_create(be->blkif, handle, major, minor, |
589 | !strchr(be->mode, 'w'), cdrom); | |
4d05a28d | 590 | |
9d092603 JB |
591 | if (err) |
592 | xenbus_dev_fatal(dev, err, "creating vbd structure"); | |
593 | else { | |
4d05a28d KRW |
594 | err = xenvbd_sysfs_addif(dev); |
595 | if (err) { | |
3d814731 | 596 | xen_vbd_free(&be->blkif->vbd); |
4d05a28d | 597 | xenbus_dev_fatal(dev, err, "creating sysfs entries"); |
4d05a28d | 598 | } |
9d092603 | 599 | } |
4d05a28d | 600 | |
9d092603 JB |
601 | if (err) { |
602 | kfree(be->mode); | |
603 | be->mode = NULL; | |
604 | be->major = 0; | |
605 | be->minor = 0; | |
606 | } else { | |
4d05a28d | 607 | /* We're potentially connected now */ |
8b6bf747 | 608 | xen_update_blkif_status(be->blkif); |
4d05a28d KRW |
609 | } |
610 | } | |
611 | ||
612 | ||
01f37f2d | 613 | /* |
4d05a28d KRW |
614 | * Callback received when the frontend's state changes. |
615 | */ | |
616 | static void frontend_changed(struct xenbus_device *dev, | |
617 | enum xenbus_state frontend_state) | |
618 | { | |
5cf6e4f6 | 619 | struct backend_info *be = dev_get_drvdata(&dev->dev); |
4d05a28d KRW |
620 | int err; |
621 | ||
622 | DPRINTK("%s", xenbus_strstate(frontend_state)); | |
623 | ||
624 | switch (frontend_state) { | |
625 | case XenbusStateInitialising: | |
626 | if (dev->state == XenbusStateClosed) { | |
22b20f2d | 627 | pr_info(DRV_PFX "%s: prepare for reconnect\n", |
ebe81906 | 628 | dev->nodename); |
4d05a28d KRW |
629 | xenbus_switch_state(dev, XenbusStateInitWait); |
630 | } | |
631 | break; | |
632 | ||
633 | case XenbusStateInitialised: | |
634 | case XenbusStateConnected: | |
01f37f2d KRW |
635 | /* |
636 | * Ensure we connect even when two watches fire in | |
42b2aa86 | 637 | * close succession and we miss the intermediate value |
01f37f2d KRW |
638 | * of frontend_state. |
639 | */ | |
4d05a28d KRW |
640 | if (dev->state == XenbusStateConnected) |
641 | break; | |
642 | ||
01f37f2d KRW |
643 | /* |
644 | * Enforce precondition before potential leak point. | |
1bc05b0a | 645 | * xen_blkif_disconnect() is idempotent. |
313d7b00 | 646 | */ |
8b6bf747 | 647 | xen_blkif_disconnect(be->blkif); |
313d7b00 | 648 | |
4d05a28d KRW |
649 | err = connect_ring(be); |
650 | if (err) | |
651 | break; | |
8b6bf747 | 652 | xen_update_blkif_status(be->blkif); |
4d05a28d KRW |
653 | break; |
654 | ||
655 | case XenbusStateClosing: | |
4d05a28d KRW |
656 | xenbus_switch_state(dev, XenbusStateClosing); |
657 | break; | |
658 | ||
659 | case XenbusStateClosed: | |
6f5986bc | 660 | xen_blkif_disconnect(be->blkif); |
4d05a28d KRW |
661 | xenbus_switch_state(dev, XenbusStateClosed); |
662 | if (xenbus_dev_is_online(dev)) | |
663 | break; | |
664 | /* fall through if not online */ | |
665 | case XenbusStateUnknown: | |
1bc05b0a | 666 | /* implies xen_blkif_disconnect() via xen_blkbk_remove() */ |
4d05a28d KRW |
667 | device_unregister(&dev->dev); |
668 | break; | |
669 | ||
670 | default: | |
671 | xenbus_dev_fatal(dev, -EINVAL, "saw state %d at frontend", | |
672 | frontend_state); | |
673 | break; | |
674 | } | |
675 | } | |
676 | ||
677 | ||
678 | /* ** Connection ** */ | |
679 | ||
680 | ||
01f37f2d | 681 | /* |
4d05a28d KRW |
682 | * Write the physical details regarding the block device to the store, and |
683 | * switch to Connected state. | |
684 | */ | |
685 | static void connect(struct backend_info *be) | |
686 | { | |
687 | struct xenbus_transaction xbt; | |
688 | int err; | |
689 | struct xenbus_device *dev = be->dev; | |
690 | ||
691 | DPRINTK("%s", dev->otherend); | |
692 | ||
693 | /* Supply the information about the device the frontend needs */ | |
694 | again: | |
695 | err = xenbus_transaction_start(&xbt); | |
696 | if (err) { | |
697 | xenbus_dev_fatal(dev, err, "starting transaction"); | |
698 | return; | |
699 | } | |
700 | ||
3389bb8b KRW |
701 | /* If we can't advertise it is OK. */ |
702 | xen_blkbk_flush_diskcache(xbt, be, be->blkif->vbd.flush_support); | |
4d05a28d | 703 | |
3389bb8b | 704 | xen_blkbk_discard(xbt, be); |
b3cb0d6a | 705 | |
3389bb8b | 706 | xen_blkbk_barrier(xbt, be, be->blkif->vbd.flush_support); |
29bde093 | 707 | |
0a8704a5 RPM |
708 | err = xenbus_printf(xbt, dev->nodename, "feature-persistent", "%u", 1); |
709 | if (err) { | |
710 | xenbus_dev_fatal(dev, err, "writing %s/feature-persistent", | |
711 | dev->nodename); | |
712 | goto abort; | |
713 | } | |
402b27f9 RPM |
714 | err = xenbus_printf(xbt, dev->nodename, "feature-max-indirect-segments", "%u", |
715 | MAX_INDIRECT_SEGMENTS); | |
716 | if (err) | |
717 | dev_warn(&dev->dev, "writing %s/feature-max-indirect-segments (%d)", | |
718 | dev->nodename, err); | |
0a8704a5 | 719 | |
4d05a28d | 720 | err = xenbus_printf(xbt, dev->nodename, "sectors", "%llu", |
42c7841d | 721 | (unsigned long long)vbd_sz(&be->blkif->vbd)); |
4d05a28d KRW |
722 | if (err) { |
723 | xenbus_dev_fatal(dev, err, "writing %s/sectors", | |
724 | dev->nodename); | |
725 | goto abort; | |
726 | } | |
727 | ||
728 | /* FIXME: use a typename instead */ | |
729 | err = xenbus_printf(xbt, dev->nodename, "info", "%u", | |
42c7841d KRW |
730 | be->blkif->vbd.type | |
731 | (be->blkif->vbd.readonly ? VDISK_READONLY : 0)); | |
4d05a28d KRW |
732 | if (err) { |
733 | xenbus_dev_fatal(dev, err, "writing %s/info", | |
734 | dev->nodename); | |
735 | goto abort; | |
736 | } | |
737 | err = xenbus_printf(xbt, dev->nodename, "sector-size", "%lu", | |
42c7841d KRW |
738 | (unsigned long) |
739 | bdev_logical_block_size(be->blkif->vbd.bdev)); | |
4d05a28d KRW |
740 | if (err) { |
741 | xenbus_dev_fatal(dev, err, "writing %s/sector-size", | |
742 | dev->nodename); | |
743 | goto abort; | |
744 | } | |
745 | ||
746 | err = xenbus_transaction_end(xbt, 0); | |
747 | if (err == -EAGAIN) | |
748 | goto again; | |
749 | if (err) | |
750 | xenbus_dev_fatal(dev, err, "ending transaction"); | |
751 | ||
752 | err = xenbus_switch_state(dev, XenbusStateConnected); | |
753 | if (err) | |
08b8bfc1 | 754 | xenbus_dev_fatal(dev, err, "%s: switching to Connected state", |
4d05a28d KRW |
755 | dev->nodename); |
756 | ||
757 | return; | |
758 | abort: | |
759 | xenbus_transaction_end(xbt, 1); | |
760 | } | |
761 | ||
762 | ||
763 | static int connect_ring(struct backend_info *be) | |
764 | { | |
765 | struct xenbus_device *dev = be->dev; | |
766 | unsigned long ring_ref; | |
767 | unsigned int evtchn; | |
0a8704a5 | 768 | unsigned int pers_grants; |
4d05a28d KRW |
769 | char protocol[64] = ""; |
770 | int err; | |
771 | ||
772 | DPRINTK("%s", dev->otherend); | |
773 | ||
d6091b21 KRW |
774 | err = xenbus_gather(XBT_NIL, dev->otherend, "ring-ref", "%lu", |
775 | &ring_ref, "event-channel", "%u", &evtchn, NULL); | |
4d05a28d KRW |
776 | if (err) { |
777 | xenbus_dev_fatal(dev, err, | |
778 | "reading %s/ring-ref and event-channel", | |
779 | dev->otherend); | |
780 | return err; | |
781 | } | |
782 | ||
783 | be->blkif->blk_protocol = BLKIF_PROTOCOL_NATIVE; | |
784 | err = xenbus_gather(XBT_NIL, dev->otherend, "protocol", | |
785 | "%63s", protocol, NULL); | |
786 | if (err) | |
787 | strcpy(protocol, "unspecified, assuming native"); | |
788 | else if (0 == strcmp(protocol, XEN_IO_PROTO_ABI_NATIVE)) | |
789 | be->blkif->blk_protocol = BLKIF_PROTOCOL_NATIVE; | |
790 | else if (0 == strcmp(protocol, XEN_IO_PROTO_ABI_X86_32)) | |
791 | be->blkif->blk_protocol = BLKIF_PROTOCOL_X86_32; | |
792 | else if (0 == strcmp(protocol, XEN_IO_PROTO_ABI_X86_64)) | |
793 | be->blkif->blk_protocol = BLKIF_PROTOCOL_X86_64; | |
794 | else { | |
795 | xenbus_dev_fatal(dev, err, "unknown fe protocol %s", protocol); | |
796 | return -1; | |
797 | } | |
0a8704a5 | 798 | err = xenbus_gather(XBT_NIL, dev->otherend, |
cb5bd4d1 | 799 | "feature-persistent", "%u", |
0a8704a5 RPM |
800 | &pers_grants, NULL); |
801 | if (err) | |
802 | pers_grants = 0; | |
803 | ||
804 | be->blkif->vbd.feature_gnt_persistent = pers_grants; | |
805 | be->blkif->vbd.overflow_max_grants = 0; | |
806 | ||
807 | pr_info(DRV_PFX "ring-ref %ld, event-channel %d, protocol %d (%s) %s\n", | |
808 | ring_ref, evtchn, be->blkif->blk_protocol, protocol, | |
809 | pers_grants ? "persistent grants" : ""); | |
4d05a28d KRW |
810 | |
811 | /* Map the shared frame, irq etc. */ | |
8b6bf747 | 812 | err = xen_blkif_map(be->blkif, ring_ref, evtchn); |
4d05a28d KRW |
813 | if (err) { |
814 | xenbus_dev_fatal(dev, err, "mapping ring-ref %lu port %u", | |
815 | ring_ref, evtchn); | |
816 | return err; | |
817 | } | |
818 | ||
819 | return 0; | |
820 | } | |
821 | ||
822 | ||
823 | /* ** Driver Registration ** */ | |
824 | ||
825 | ||
8b6bf747 | 826 | static const struct xenbus_device_id xen_blkbk_ids[] = { |
4d05a28d KRW |
827 | { "vbd" }, |
828 | { "" } | |
829 | }; | |
830 | ||
831 | ||
73db144b | 832 | static DEFINE_XENBUS_DRIVER(xen_blkbk, , |
8b6bf747 KRW |
833 | .probe = xen_blkbk_probe, |
834 | .remove = xen_blkbk_remove, | |
4d05a28d | 835 | .otherend_changed = frontend_changed |
73db144b | 836 | ); |
4d05a28d KRW |
837 | |
838 | ||
8b6bf747 | 839 | int xen_blkif_xenbus_init(void) |
4d05a28d | 840 | { |
73db144b | 841 | return xenbus_register_backend(&xen_blkbk_driver); |
4d05a28d | 842 | } |