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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 | ||
f170168b | 96 | blkif->xenblkd = kthread_run(xen_blkif_schedule, blkif, "%s", 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; |
bb642e83 RPM |
108 | struct pending_req *req, *n; |
109 | int i, j; | |
ee9ff853 | 110 | |
402b27f9 | 111 | BUILD_BUG_ON(MAX_INDIRECT_PAGES > BLKIF_MAX_INDIRECT_PAGES_PER_REQUEST); |
ee9ff853 | 112 | |
654dbef2 | 113 | blkif = kmem_cache_zalloc(xen_blkif_cachep, GFP_KERNEL); |
ee9ff853 KRW |
114 | if (!blkif) |
115 | return ERR_PTR(-ENOMEM); | |
116 | ||
ee9ff853 KRW |
117 | blkif->domid = domid; |
118 | spin_lock_init(&blkif->blk_ring_lock); | |
119 | atomic_set(&blkif->refcnt, 1); | |
120 | init_waitqueue_head(&blkif->wq); | |
29bde093 KRW |
121 | init_completion(&blkif->drain_complete); |
122 | atomic_set(&blkif->drain, 0); | |
ee9ff853 KRW |
123 | blkif->st_print = jiffies; |
124 | init_waitqueue_head(&blkif->waiting_to_free); | |
0a8704a5 | 125 | blkif->persistent_gnts.rb_node = NULL; |
c6cc142d RPM |
126 | spin_lock_init(&blkif->free_pages_lock); |
127 | INIT_LIST_HEAD(&blkif->free_pages); | |
ef753411 | 128 | INIT_LIST_HEAD(&blkif->persistent_purge_list); |
c6cc142d | 129 | blkif->free_pages_num = 0; |
3f3aad5e | 130 | atomic_set(&blkif->persistent_gnt_in_use, 0); |
c05f3e3c | 131 | atomic_set(&blkif->inflight, 0); |
abb97b8c | 132 | INIT_WORK(&blkif->persistent_purge_work, xen_blkbk_unmap_purged_grants); |
ee9ff853 | 133 | |
bf0720c4 | 134 | INIT_LIST_HEAD(&blkif->pending_free); |
bb642e83 RPM |
135 | |
136 | for (i = 0; i < XEN_BLKIF_REQS; i++) { | |
137 | req = kzalloc(sizeof(*req), GFP_KERNEL); | |
138 | if (!req) | |
139 | goto fail; | |
140 | list_add_tail(&req->free_list, | |
141 | &blkif->pending_free); | |
142 | for (j = 0; j < MAX_INDIRECT_SEGMENTS; j++) { | |
143 | req->segments[j] = kzalloc(sizeof(*req->segments[0]), | |
144 | GFP_KERNEL); | |
145 | if (!req->segments[j]) | |
146 | goto fail; | |
147 | } | |
148 | for (j = 0; j < MAX_INDIRECT_PAGES; j++) { | |
149 | req->indirect_pages[j] = kzalloc(sizeof(*req->indirect_pages[0]), | |
150 | GFP_KERNEL); | |
151 | if (!req->indirect_pages[j]) | |
152 | goto fail; | |
153 | } | |
154 | } | |
bf0720c4 RPM |
155 | spin_lock_init(&blkif->pending_free_lock); |
156 | init_waitqueue_head(&blkif->pending_free_wq); | |
8e3f8755 | 157 | init_waitqueue_head(&blkif->shutdown_wq); |
ee9ff853 KRW |
158 | |
159 | return blkif; | |
bb642e83 RPM |
160 | |
161 | fail: | |
162 | list_for_each_entry_safe(req, n, &blkif->pending_free, free_list) { | |
163 | list_del(&req->free_list); | |
164 | for (j = 0; j < MAX_INDIRECT_SEGMENTS; j++) { | |
165 | if (!req->segments[j]) | |
166 | break; | |
167 | kfree(req->segments[j]); | |
168 | } | |
169 | for (j = 0; j < MAX_INDIRECT_PAGES; j++) { | |
170 | if (!req->indirect_pages[j]) | |
171 | break; | |
172 | kfree(req->indirect_pages[j]); | |
173 | } | |
174 | kfree(req); | |
175 | } | |
176 | ||
177 | kmem_cache_free(xen_blkif_cachep, blkif); | |
178 | ||
179 | return ERR_PTR(-ENOMEM); | |
ee9ff853 KRW |
180 | } |
181 | ||
30fd1502 | 182 | static int xen_blkif_map(struct xen_blkif *blkif, unsigned long shared_page, |
8b6bf747 | 183 | unsigned int evtchn) |
ee9ff853 KRW |
184 | { |
185 | int err; | |
186 | ||
187 | /* Already connected through? */ | |
188 | if (blkif->irq) | |
189 | return 0; | |
190 | ||
2d073846 DV |
191 | err = xenbus_map_ring_valloc(blkif->be->dev, shared_page, &blkif->blk_ring); |
192 | if (err < 0) | |
ee9ff853 | 193 | return err; |
ee9ff853 KRW |
194 | |
195 | switch (blkif->blk_protocol) { | |
196 | case BLKIF_PROTOCOL_NATIVE: | |
197 | { | |
198 | struct blkif_sring *sring; | |
2d073846 | 199 | sring = (struct blkif_sring *)blkif->blk_ring; |
ee9ff853 KRW |
200 | BACK_RING_INIT(&blkif->blk_rings.native, sring, PAGE_SIZE); |
201 | break; | |
202 | } | |
203 | case BLKIF_PROTOCOL_X86_32: | |
204 | { | |
205 | struct blkif_x86_32_sring *sring_x86_32; | |
2d073846 | 206 | sring_x86_32 = (struct blkif_x86_32_sring *)blkif->blk_ring; |
ee9ff853 KRW |
207 | BACK_RING_INIT(&blkif->blk_rings.x86_32, sring_x86_32, PAGE_SIZE); |
208 | break; | |
209 | } | |
210 | case BLKIF_PROTOCOL_X86_64: | |
211 | { | |
212 | struct blkif_x86_64_sring *sring_x86_64; | |
2d073846 | 213 | sring_x86_64 = (struct blkif_x86_64_sring *)blkif->blk_ring; |
ee9ff853 KRW |
214 | BACK_RING_INIT(&blkif->blk_rings.x86_64, sring_x86_64, PAGE_SIZE); |
215 | break; | |
216 | } | |
217 | default: | |
218 | BUG(); | |
219 | } | |
220 | ||
8b6bf747 KRW |
221 | err = bind_interdomain_evtchn_to_irqhandler(blkif->domid, evtchn, |
222 | xen_blkif_be_int, 0, | |
223 | "blkif-backend", blkif); | |
ee9ff853 | 224 | if (err < 0) { |
2d073846 | 225 | xenbus_unmap_ring_vfree(blkif->be->dev, blkif->blk_ring); |
ee9ff853 KRW |
226 | blkif->blk_rings.common.sring = NULL; |
227 | return err; | |
228 | } | |
229 | blkif->irq = err; | |
230 | ||
231 | return 0; | |
232 | } | |
233 | ||
30fd1502 | 234 | static void xen_blkif_disconnect(struct xen_blkif *blkif) |
ee9ff853 KRW |
235 | { |
236 | if (blkif->xenblkd) { | |
237 | kthread_stop(blkif->xenblkd); | |
8e3f8755 | 238 | wake_up(&blkif->shutdown_wq); |
ee9ff853 KRW |
239 | blkif->xenblkd = NULL; |
240 | } | |
241 | ||
242 | atomic_dec(&blkif->refcnt); | |
243 | wait_event(blkif->waiting_to_free, atomic_read(&blkif->refcnt) == 0); | |
244 | atomic_inc(&blkif->refcnt); | |
245 | ||
246 | if (blkif->irq) { | |
247 | unbind_from_irqhandler(blkif->irq, blkif); | |
248 | blkif->irq = 0; | |
249 | } | |
250 | ||
251 | if (blkif->blk_rings.common.sring) { | |
2d073846 | 252 | xenbus_unmap_ring_vfree(blkif->be->dev, blkif->blk_ring); |
ee9ff853 KRW |
253 | blkif->blk_rings.common.sring = NULL; |
254 | } | |
255 | } | |
256 | ||
2911758f | 257 | static void xen_blkif_free(struct xen_blkif *blkif) |
ee9ff853 | 258 | { |
bb642e83 RPM |
259 | struct pending_req *req, *n; |
260 | int i = 0, j; | |
bf0720c4 | 261 | |
ee9ff853 KRW |
262 | if (!atomic_dec_and_test(&blkif->refcnt)) |
263 | BUG(); | |
bf0720c4 | 264 | |
ef753411 RPM |
265 | /* Remove all persistent grants and the cache of ballooned pages. */ |
266 | xen_blkbk_free_caches(blkif); | |
267 | ||
268 | /* Make sure everything is drained before shutting down */ | |
269 | BUG_ON(blkif->persistent_gnt_c != 0); | |
270 | BUG_ON(atomic_read(&blkif->persistent_gnt_in_use) != 0); | |
271 | BUG_ON(blkif->free_pages_num != 0); | |
272 | BUG_ON(!list_empty(&blkif->persistent_purge_list)); | |
273 | BUG_ON(!list_empty(&blkif->free_pages)); | |
274 | BUG_ON(!RB_EMPTY_ROOT(&blkif->persistent_gnts)); | |
275 | ||
bf0720c4 | 276 | /* Check that there is no request in use */ |
bb642e83 RPM |
277 | list_for_each_entry_safe(req, n, &blkif->pending_free, free_list) { |
278 | list_del(&req->free_list); | |
279 | ||
280 | for (j = 0; j < MAX_INDIRECT_SEGMENTS; j++) | |
281 | kfree(req->segments[j]); | |
282 | ||
283 | for (j = 0; j < MAX_INDIRECT_PAGES; j++) | |
284 | kfree(req->indirect_pages[j]); | |
285 | ||
286 | kfree(req); | |
bf0720c4 | 287 | i++; |
bb642e83 RPM |
288 | } |
289 | ||
290 | WARN_ON(i != XEN_BLKIF_REQS); | |
bf0720c4 | 291 | |
8b6bf747 | 292 | kmem_cache_free(xen_blkif_cachep, blkif); |
ee9ff853 KRW |
293 | } |
294 | ||
8b6bf747 | 295 | int __init xen_blkif_interface_init(void) |
ee9ff853 | 296 | { |
8b6bf747 | 297 | xen_blkif_cachep = kmem_cache_create("blkif_cache", |
30fd1502 | 298 | sizeof(struct xen_blkif), |
8b6bf747 KRW |
299 | 0, 0, NULL); |
300 | if (!xen_blkif_cachep) | |
ee9ff853 KRW |
301 | return -ENOMEM; |
302 | ||
303 | return 0; | |
304 | } | |
4d05a28d | 305 | |
a1397fa3 | 306 | /* |
4d05a28d KRW |
307 | * sysfs interface for VBD I/O requests |
308 | */ | |
309 | ||
310 | #define VBD_SHOW(name, format, args...) \ | |
311 | static ssize_t show_##name(struct device *_dev, \ | |
312 | struct device_attribute *attr, \ | |
313 | char *buf) \ | |
314 | { \ | |
315 | struct xenbus_device *dev = to_xenbus_device(_dev); \ | |
5cf6e4f6 | 316 | struct backend_info *be = dev_get_drvdata(&dev->dev); \ |
4d05a28d KRW |
317 | \ |
318 | return sprintf(buf, format, ##args); \ | |
319 | } \ | |
320 | static DEVICE_ATTR(name, S_IRUGO, show_##name, NULL) | |
321 | ||
986cacbd ZK |
322 | VBD_SHOW(oo_req, "%llu\n", be->blkif->st_oo_req); |
323 | VBD_SHOW(rd_req, "%llu\n", be->blkif->st_rd_req); | |
324 | VBD_SHOW(wr_req, "%llu\n", be->blkif->st_wr_req); | |
325 | VBD_SHOW(f_req, "%llu\n", be->blkif->st_f_req); | |
326 | VBD_SHOW(ds_req, "%llu\n", be->blkif->st_ds_req); | |
327 | VBD_SHOW(rd_sect, "%llu\n", be->blkif->st_rd_sect); | |
328 | VBD_SHOW(wr_sect, "%llu\n", be->blkif->st_wr_sect); | |
4d05a28d | 329 | |
3d814731 | 330 | static struct attribute *xen_vbdstat_attrs[] = { |
4d05a28d KRW |
331 | &dev_attr_oo_req.attr, |
332 | &dev_attr_rd_req.attr, | |
333 | &dev_attr_wr_req.attr, | |
24f567f9 | 334 | &dev_attr_f_req.attr, |
b3cb0d6a | 335 | &dev_attr_ds_req.attr, |
4d05a28d KRW |
336 | &dev_attr_rd_sect.attr, |
337 | &dev_attr_wr_sect.attr, | |
338 | NULL | |
339 | }; | |
340 | ||
3d814731 | 341 | static struct attribute_group xen_vbdstat_group = { |
4d05a28d | 342 | .name = "statistics", |
3d814731 | 343 | .attrs = xen_vbdstat_attrs, |
4d05a28d KRW |
344 | }; |
345 | ||
346 | VBD_SHOW(physical_device, "%x:%x\n", be->major, be->minor); | |
347 | VBD_SHOW(mode, "%s\n", be->mode); | |
348 | ||
2911758f | 349 | static int xenvbd_sysfs_addif(struct xenbus_device *dev) |
4d05a28d KRW |
350 | { |
351 | int error; | |
352 | ||
353 | error = device_create_file(&dev->dev, &dev_attr_physical_device); | |
d6091b21 | 354 | if (error) |
4d05a28d KRW |
355 | goto fail1; |
356 | ||
357 | error = device_create_file(&dev->dev, &dev_attr_mode); | |
358 | if (error) | |
359 | goto fail2; | |
360 | ||
3d814731 | 361 | error = sysfs_create_group(&dev->dev.kobj, &xen_vbdstat_group); |
4d05a28d KRW |
362 | if (error) |
363 | goto fail3; | |
364 | ||
365 | return 0; | |
366 | ||
3d814731 | 367 | fail3: sysfs_remove_group(&dev->dev.kobj, &xen_vbdstat_group); |
4d05a28d KRW |
368 | fail2: device_remove_file(&dev->dev, &dev_attr_mode); |
369 | fail1: device_remove_file(&dev->dev, &dev_attr_physical_device); | |
370 | return error; | |
371 | } | |
372 | ||
2911758f | 373 | static void xenvbd_sysfs_delif(struct xenbus_device *dev) |
4d05a28d | 374 | { |
3d814731 | 375 | sysfs_remove_group(&dev->dev.kobj, &xen_vbdstat_group); |
4d05a28d KRW |
376 | device_remove_file(&dev->dev, &dev_attr_mode); |
377 | device_remove_file(&dev->dev, &dev_attr_physical_device); | |
378 | } | |
379 | ||
42c7841d | 380 | |
3d814731 | 381 | static void xen_vbd_free(struct xen_vbd *vbd) |
42c7841d KRW |
382 | { |
383 | if (vbd->bdev) | |
384 | blkdev_put(vbd->bdev, vbd->readonly ? FMODE_READ : FMODE_WRITE); | |
385 | vbd->bdev = NULL; | |
386 | } | |
387 | ||
3d814731 KRW |
388 | static int xen_vbd_create(struct xen_blkif *blkif, blkif_vdev_t handle, |
389 | unsigned major, unsigned minor, int readonly, | |
390 | int cdrom) | |
42c7841d | 391 | { |
3d814731 | 392 | struct xen_vbd *vbd; |
42c7841d | 393 | struct block_device *bdev; |
24f567f9 | 394 | struct request_queue *q; |
42c7841d KRW |
395 | |
396 | vbd = &blkif->vbd; | |
397 | vbd->handle = handle; | |
398 | vbd->readonly = readonly; | |
399 | vbd->type = 0; | |
400 | ||
401 | vbd->pdevice = MKDEV(major, minor); | |
402 | ||
403 | bdev = blkdev_get_by_dev(vbd->pdevice, vbd->readonly ? | |
404 | FMODE_READ : FMODE_WRITE, NULL); | |
405 | ||
406 | if (IS_ERR(bdev)) { | |
3d814731 | 407 | DPRINTK("xen_vbd_create: device %08x could not be opened.\n", |
42c7841d KRW |
408 | vbd->pdevice); |
409 | return -ENOENT; | |
410 | } | |
411 | ||
412 | vbd->bdev = bdev; | |
42c7841d | 413 | if (vbd->bdev->bd_disk == NULL) { |
3d814731 | 414 | DPRINTK("xen_vbd_create: device %08x doesn't exist.\n", |
42c7841d | 415 | vbd->pdevice); |
3d814731 | 416 | xen_vbd_free(vbd); |
42c7841d KRW |
417 | return -ENOENT; |
418 | } | |
6464920a | 419 | vbd->size = vbd_sz(vbd); |
42c7841d KRW |
420 | |
421 | if (vbd->bdev->bd_disk->flags & GENHD_FL_CD || cdrom) | |
422 | vbd->type |= VDISK_CDROM; | |
423 | if (vbd->bdev->bd_disk->flags & GENHD_FL_REMOVABLE) | |
424 | vbd->type |= VDISK_REMOVABLE; | |
425 | ||
24f567f9 KRW |
426 | q = bdev_get_queue(bdev); |
427 | if (q && q->flush_flags) | |
428 | vbd->flush_support = true; | |
429 | ||
5ea42986 KRW |
430 | if (q && blk_queue_secdiscard(q)) |
431 | vbd->discard_secure = true; | |
432 | ||
42c7841d KRW |
433 | DPRINTK("Successful creation of handle=%04x (dom=%u)\n", |
434 | handle, blkif->domid); | |
435 | return 0; | |
436 | } | |
8b6bf747 | 437 | static int xen_blkbk_remove(struct xenbus_device *dev) |
4d05a28d | 438 | { |
5cf6e4f6 | 439 | struct backend_info *be = dev_get_drvdata(&dev->dev); |
4d05a28d KRW |
440 | |
441 | DPRINTK(""); | |
442 | ||
443 | if (be->major || be->minor) | |
444 | xenvbd_sysfs_delif(dev); | |
445 | ||
446 | if (be->backend_watch.node) { | |
447 | unregister_xenbus_watch(&be->backend_watch); | |
448 | kfree(be->backend_watch.node); | |
449 | be->backend_watch.node = NULL; | |
450 | } | |
451 | ||
452 | if (be->blkif) { | |
8b6bf747 | 453 | xen_blkif_disconnect(be->blkif); |
3d814731 | 454 | xen_vbd_free(&be->blkif->vbd); |
8b6bf747 | 455 | xen_blkif_free(be->blkif); |
4d05a28d KRW |
456 | be->blkif = NULL; |
457 | } | |
458 | ||
9d092603 | 459 | kfree(be->mode); |
4d05a28d | 460 | kfree(be); |
5cf6e4f6 | 461 | dev_set_drvdata(&dev->dev, NULL); |
4d05a28d KRW |
462 | return 0; |
463 | } | |
464 | ||
24f567f9 KRW |
465 | int xen_blkbk_flush_diskcache(struct xenbus_transaction xbt, |
466 | struct backend_info *be, int state) | |
4d05a28d KRW |
467 | { |
468 | struct xenbus_device *dev = be->dev; | |
469 | int err; | |
470 | ||
24f567f9 | 471 | err = xenbus_printf(xbt, dev->nodename, "feature-flush-cache", |
4d05a28d KRW |
472 | "%d", state); |
473 | if (err) | |
3389bb8b | 474 | dev_warn(&dev->dev, "writing feature-flush-cache (%d)", err); |
4d05a28d KRW |
475 | |
476 | return err; | |
477 | } | |
478 | ||
3389bb8b | 479 | static void xen_blkbk_discard(struct xenbus_transaction xbt, struct backend_info *be) |
b3cb0d6a LD |
480 | { |
481 | struct xenbus_device *dev = be->dev; | |
482 | struct xen_blkif *blkif = be->blkif; | |
b3cb0d6a LD |
483 | int err; |
484 | int state = 0; | |
4dae7670 KRW |
485 | struct block_device *bdev = be->blkif->vbd.bdev; |
486 | struct request_queue *q = bdev_get_queue(bdev); | |
487 | ||
488 | if (blk_queue_discard(q)) { | |
489 | err = xenbus_printf(xbt, dev->nodename, | |
490 | "discard-granularity", "%u", | |
491 | q->limits.discard_granularity); | |
492 | if (err) { | |
3389bb8b KRW |
493 | dev_warn(&dev->dev, "writing discard-granularity (%d)", err); |
494 | return; | |
4dae7670 KRW |
495 | } |
496 | err = xenbus_printf(xbt, dev->nodename, | |
497 | "discard-alignment", "%u", | |
498 | q->limits.discard_alignment); | |
499 | if (err) { | |
3389bb8b KRW |
500 | dev_warn(&dev->dev, "writing discard-alignment (%d)", err); |
501 | return; | |
b3cb0d6a | 502 | } |
4dae7670 KRW |
503 | state = 1; |
504 | /* Optional. */ | |
505 | err = xenbus_printf(xbt, dev->nodename, | |
506 | "discard-secure", "%d", | |
507 | blkif->vbd.discard_secure); | |
508 | if (err) { | |
a71e23d9 | 509 | dev_warn(&dev->dev, "writing discard-secure (%d)", err); |
3389bb8b | 510 | return; |
b3cb0d6a | 511 | } |
b3cb0d6a | 512 | } |
b3cb0d6a LD |
513 | err = xenbus_printf(xbt, dev->nodename, "feature-discard", |
514 | "%d", state); | |
515 | if (err) | |
3389bb8b | 516 | dev_warn(&dev->dev, "writing feature-discard (%d)", err); |
b3cb0d6a | 517 | } |
29bde093 KRW |
518 | int xen_blkbk_barrier(struct xenbus_transaction xbt, |
519 | struct backend_info *be, int state) | |
520 | { | |
521 | struct xenbus_device *dev = be->dev; | |
522 | int err; | |
523 | ||
524 | err = xenbus_printf(xbt, dev->nodename, "feature-barrier", | |
525 | "%d", state); | |
526 | if (err) | |
3389bb8b | 527 | dev_warn(&dev->dev, "writing feature-barrier (%d)", err); |
29bde093 KRW |
528 | |
529 | return err; | |
530 | } | |
b3cb0d6a | 531 | |
01f37f2d | 532 | /* |
4d05a28d KRW |
533 | * Entry point to this code when a new device is created. Allocate the basic |
534 | * structures, and watch the store waiting for the hotplug scripts to tell us | |
535 | * the device's physical major and minor numbers. Switch to InitWait. | |
536 | */ | |
8b6bf747 KRW |
537 | static int xen_blkbk_probe(struct xenbus_device *dev, |
538 | const struct xenbus_device_id *id) | |
4d05a28d KRW |
539 | { |
540 | int err; | |
541 | struct backend_info *be = kzalloc(sizeof(struct backend_info), | |
542 | GFP_KERNEL); | |
543 | if (!be) { | |
544 | xenbus_dev_fatal(dev, -ENOMEM, | |
545 | "allocating backend structure"); | |
546 | return -ENOMEM; | |
547 | } | |
548 | be->dev = dev; | |
5cf6e4f6 | 549 | dev_set_drvdata(&dev->dev, be); |
4d05a28d | 550 | |
8b6bf747 | 551 | be->blkif = xen_blkif_alloc(dev->otherend_id); |
4d05a28d KRW |
552 | if (IS_ERR(be->blkif)) { |
553 | err = PTR_ERR(be->blkif); | |
554 | be->blkif = NULL; | |
555 | xenbus_dev_fatal(dev, err, "creating block interface"); | |
556 | goto fail; | |
557 | } | |
558 | ||
559 | /* setup back pointer */ | |
560 | be->blkif->be = be; | |
561 | ||
88122933 JF |
562 | err = xenbus_watch_pathfmt(dev, &be->backend_watch, backend_changed, |
563 | "%s/%s", dev->nodename, "physical-device"); | |
4d05a28d KRW |
564 | if (err) |
565 | goto fail; | |
566 | ||
567 | err = xenbus_switch_state(dev, XenbusStateInitWait); | |
568 | if (err) | |
569 | goto fail; | |
570 | ||
571 | return 0; | |
572 | ||
573 | fail: | |
574 | DPRINTK("failed"); | |
8b6bf747 | 575 | xen_blkbk_remove(dev); |
4d05a28d KRW |
576 | return err; |
577 | } | |
578 | ||
579 | ||
01f37f2d | 580 | /* |
4d05a28d KRW |
581 | * Callback received when the hotplug scripts have placed the physical-device |
582 | * node. Read it and the mode node, and create a vbd. If the frontend is | |
583 | * ready, connect. | |
584 | */ | |
585 | static void backend_changed(struct xenbus_watch *watch, | |
586 | const char **vec, unsigned int len) | |
587 | { | |
588 | int err; | |
589 | unsigned major; | |
590 | unsigned minor; | |
591 | struct backend_info *be | |
592 | = container_of(watch, struct backend_info, backend_watch); | |
593 | struct xenbus_device *dev = be->dev; | |
594 | int cdrom = 0; | |
9d092603 | 595 | unsigned long handle; |
4d05a28d KRW |
596 | char *device_type; |
597 | ||
598 | DPRINTK(""); | |
599 | ||
600 | err = xenbus_scanf(XBT_NIL, dev->nodename, "physical-device", "%x:%x", | |
601 | &major, &minor); | |
602 | if (XENBUS_EXIST_ERR(err)) { | |
01f37f2d KRW |
603 | /* |
604 | * Since this watch will fire once immediately after it is | |
605 | * registered, we expect this. Ignore it, and wait for the | |
606 | * hotplug scripts. | |
607 | */ | |
4d05a28d KRW |
608 | return; |
609 | } | |
610 | if (err != 2) { | |
611 | xenbus_dev_fatal(dev, err, "reading physical-device"); | |
612 | return; | |
613 | } | |
614 | ||
9d092603 JB |
615 | if (be->major | be->minor) { |
616 | if (be->major != major || be->minor != minor) | |
617 | pr_warn(DRV_PFX "changing physical device (from %x:%x to %x:%x) not supported.\n", | |
618 | be->major, be->minor, major, minor); | |
4d05a28d KRW |
619 | return; |
620 | } | |
621 | ||
622 | be->mode = xenbus_read(XBT_NIL, dev->nodename, "mode", NULL); | |
623 | if (IS_ERR(be->mode)) { | |
624 | err = PTR_ERR(be->mode); | |
625 | be->mode = NULL; | |
626 | xenbus_dev_fatal(dev, err, "reading mode"); | |
627 | return; | |
628 | } | |
629 | ||
630 | device_type = xenbus_read(XBT_NIL, dev->otherend, "device-type", NULL); | |
631 | if (!IS_ERR(device_type)) { | |
632 | cdrom = strcmp(device_type, "cdrom") == 0; | |
633 | kfree(device_type); | |
634 | } | |
635 | ||
9d092603 | 636 | /* Front end dir is a number, which is used as the handle. */ |
bb8e0e84 | 637 | err = kstrtoul(strrchr(dev->otherend, '/') + 1, 0, &handle); |
9d092603 JB |
638 | if (err) |
639 | return; | |
4d05a28d | 640 | |
9d092603 JB |
641 | be->major = major; |
642 | be->minor = minor; | |
4d05a28d | 643 | |
9d092603 JB |
644 | err = xen_vbd_create(be->blkif, handle, major, minor, |
645 | !strchr(be->mode, 'w'), cdrom); | |
4d05a28d | 646 | |
9d092603 JB |
647 | if (err) |
648 | xenbus_dev_fatal(dev, err, "creating vbd structure"); | |
649 | else { | |
4d05a28d KRW |
650 | err = xenvbd_sysfs_addif(dev); |
651 | if (err) { | |
3d814731 | 652 | xen_vbd_free(&be->blkif->vbd); |
4d05a28d | 653 | xenbus_dev_fatal(dev, err, "creating sysfs entries"); |
4d05a28d | 654 | } |
9d092603 | 655 | } |
4d05a28d | 656 | |
9d092603 JB |
657 | if (err) { |
658 | kfree(be->mode); | |
659 | be->mode = NULL; | |
660 | be->major = 0; | |
661 | be->minor = 0; | |
662 | } else { | |
4d05a28d | 663 | /* We're potentially connected now */ |
8b6bf747 | 664 | xen_update_blkif_status(be->blkif); |
4d05a28d KRW |
665 | } |
666 | } | |
667 | ||
668 | ||
01f37f2d | 669 | /* |
4d05a28d KRW |
670 | * Callback received when the frontend's state changes. |
671 | */ | |
672 | static void frontend_changed(struct xenbus_device *dev, | |
673 | enum xenbus_state frontend_state) | |
674 | { | |
5cf6e4f6 | 675 | struct backend_info *be = dev_get_drvdata(&dev->dev); |
4d05a28d KRW |
676 | int err; |
677 | ||
678 | DPRINTK("%s", xenbus_strstate(frontend_state)); | |
679 | ||
680 | switch (frontend_state) { | |
681 | case XenbusStateInitialising: | |
682 | if (dev->state == XenbusStateClosed) { | |
22b20f2d | 683 | pr_info(DRV_PFX "%s: prepare for reconnect\n", |
ebe81906 | 684 | dev->nodename); |
4d05a28d KRW |
685 | xenbus_switch_state(dev, XenbusStateInitWait); |
686 | } | |
687 | break; | |
688 | ||
689 | case XenbusStateInitialised: | |
690 | case XenbusStateConnected: | |
01f37f2d KRW |
691 | /* |
692 | * Ensure we connect even when two watches fire in | |
42b2aa86 | 693 | * close succession and we miss the intermediate value |
01f37f2d KRW |
694 | * of frontend_state. |
695 | */ | |
4d05a28d KRW |
696 | if (dev->state == XenbusStateConnected) |
697 | break; | |
698 | ||
01f37f2d KRW |
699 | /* |
700 | * Enforce precondition before potential leak point. | |
1bc05b0a | 701 | * xen_blkif_disconnect() is idempotent. |
313d7b00 | 702 | */ |
8b6bf747 | 703 | xen_blkif_disconnect(be->blkif); |
313d7b00 | 704 | |
4d05a28d KRW |
705 | err = connect_ring(be); |
706 | if (err) | |
707 | break; | |
8b6bf747 | 708 | xen_update_blkif_status(be->blkif); |
4d05a28d KRW |
709 | break; |
710 | ||
711 | case XenbusStateClosing: | |
4d05a28d KRW |
712 | xenbus_switch_state(dev, XenbusStateClosing); |
713 | break; | |
714 | ||
715 | case XenbusStateClosed: | |
6f5986bc | 716 | xen_blkif_disconnect(be->blkif); |
4d05a28d KRW |
717 | xenbus_switch_state(dev, XenbusStateClosed); |
718 | if (xenbus_dev_is_online(dev)) | |
719 | break; | |
720 | /* fall through if not online */ | |
721 | case XenbusStateUnknown: | |
1bc05b0a | 722 | /* implies xen_blkif_disconnect() via xen_blkbk_remove() */ |
4d05a28d KRW |
723 | device_unregister(&dev->dev); |
724 | break; | |
725 | ||
726 | default: | |
727 | xenbus_dev_fatal(dev, -EINVAL, "saw state %d at frontend", | |
728 | frontend_state); | |
729 | break; | |
730 | } | |
731 | } | |
732 | ||
733 | ||
734 | /* ** Connection ** */ | |
735 | ||
736 | ||
01f37f2d | 737 | /* |
4d05a28d KRW |
738 | * Write the physical details regarding the block device to the store, and |
739 | * switch to Connected state. | |
740 | */ | |
741 | static void connect(struct backend_info *be) | |
742 | { | |
743 | struct xenbus_transaction xbt; | |
744 | int err; | |
745 | struct xenbus_device *dev = be->dev; | |
746 | ||
747 | DPRINTK("%s", dev->otherend); | |
748 | ||
749 | /* Supply the information about the device the frontend needs */ | |
750 | again: | |
751 | err = xenbus_transaction_start(&xbt); | |
752 | if (err) { | |
753 | xenbus_dev_fatal(dev, err, "starting transaction"); | |
754 | return; | |
755 | } | |
756 | ||
3389bb8b KRW |
757 | /* If we can't advertise it is OK. */ |
758 | xen_blkbk_flush_diskcache(xbt, be, be->blkif->vbd.flush_support); | |
4d05a28d | 759 | |
3389bb8b | 760 | xen_blkbk_discard(xbt, be); |
b3cb0d6a | 761 | |
3389bb8b | 762 | xen_blkbk_barrier(xbt, be, be->blkif->vbd.flush_support); |
29bde093 | 763 | |
0a8704a5 RPM |
764 | err = xenbus_printf(xbt, dev->nodename, "feature-persistent", "%u", 1); |
765 | if (err) { | |
766 | xenbus_dev_fatal(dev, err, "writing %s/feature-persistent", | |
767 | dev->nodename); | |
768 | goto abort; | |
769 | } | |
402b27f9 RPM |
770 | err = xenbus_printf(xbt, dev->nodename, "feature-max-indirect-segments", "%u", |
771 | MAX_INDIRECT_SEGMENTS); | |
772 | if (err) | |
773 | dev_warn(&dev->dev, "writing %s/feature-max-indirect-segments (%d)", | |
774 | dev->nodename, err); | |
0a8704a5 | 775 | |
4d05a28d | 776 | err = xenbus_printf(xbt, dev->nodename, "sectors", "%llu", |
42c7841d | 777 | (unsigned long long)vbd_sz(&be->blkif->vbd)); |
4d05a28d KRW |
778 | if (err) { |
779 | xenbus_dev_fatal(dev, err, "writing %s/sectors", | |
780 | dev->nodename); | |
781 | goto abort; | |
782 | } | |
783 | ||
784 | /* FIXME: use a typename instead */ | |
785 | err = xenbus_printf(xbt, dev->nodename, "info", "%u", | |
42c7841d KRW |
786 | be->blkif->vbd.type | |
787 | (be->blkif->vbd.readonly ? VDISK_READONLY : 0)); | |
4d05a28d KRW |
788 | if (err) { |
789 | xenbus_dev_fatal(dev, err, "writing %s/info", | |
790 | dev->nodename); | |
791 | goto abort; | |
792 | } | |
793 | err = xenbus_printf(xbt, dev->nodename, "sector-size", "%lu", | |
42c7841d KRW |
794 | (unsigned long) |
795 | bdev_logical_block_size(be->blkif->vbd.bdev)); | |
4d05a28d KRW |
796 | if (err) { |
797 | xenbus_dev_fatal(dev, err, "writing %s/sector-size", | |
798 | dev->nodename); | |
799 | goto abort; | |
800 | } | |
7c4d7d71 SB |
801 | err = xenbus_printf(xbt, dev->nodename, "physical-sector-size", "%u", |
802 | bdev_physical_block_size(be->blkif->vbd.bdev)); | |
803 | if (err) | |
804 | xenbus_dev_error(dev, err, "writing %s/physical-sector-size", | |
805 | dev->nodename); | |
4d05a28d KRW |
806 | |
807 | err = xenbus_transaction_end(xbt, 0); | |
808 | if (err == -EAGAIN) | |
809 | goto again; | |
810 | if (err) | |
811 | xenbus_dev_fatal(dev, err, "ending transaction"); | |
812 | ||
813 | err = xenbus_switch_state(dev, XenbusStateConnected); | |
814 | if (err) | |
08b8bfc1 | 815 | xenbus_dev_fatal(dev, err, "%s: switching to Connected state", |
4d05a28d KRW |
816 | dev->nodename); |
817 | ||
818 | return; | |
819 | abort: | |
820 | xenbus_transaction_end(xbt, 1); | |
821 | } | |
822 | ||
823 | ||
824 | static int connect_ring(struct backend_info *be) | |
825 | { | |
826 | struct xenbus_device *dev = be->dev; | |
827 | unsigned long ring_ref; | |
828 | unsigned int evtchn; | |
0a8704a5 | 829 | unsigned int pers_grants; |
4d05a28d KRW |
830 | char protocol[64] = ""; |
831 | int err; | |
832 | ||
833 | DPRINTK("%s", dev->otherend); | |
834 | ||
d6091b21 KRW |
835 | err = xenbus_gather(XBT_NIL, dev->otherend, "ring-ref", "%lu", |
836 | &ring_ref, "event-channel", "%u", &evtchn, NULL); | |
4d05a28d KRW |
837 | if (err) { |
838 | xenbus_dev_fatal(dev, err, | |
839 | "reading %s/ring-ref and event-channel", | |
840 | dev->otherend); | |
841 | return err; | |
842 | } | |
843 | ||
844 | be->blkif->blk_protocol = BLKIF_PROTOCOL_NATIVE; | |
845 | err = xenbus_gather(XBT_NIL, dev->otherend, "protocol", | |
846 | "%63s", protocol, NULL); | |
847 | if (err) | |
848 | strcpy(protocol, "unspecified, assuming native"); | |
849 | else if (0 == strcmp(protocol, XEN_IO_PROTO_ABI_NATIVE)) | |
850 | be->blkif->blk_protocol = BLKIF_PROTOCOL_NATIVE; | |
851 | else if (0 == strcmp(protocol, XEN_IO_PROTO_ABI_X86_32)) | |
852 | be->blkif->blk_protocol = BLKIF_PROTOCOL_X86_32; | |
853 | else if (0 == strcmp(protocol, XEN_IO_PROTO_ABI_X86_64)) | |
854 | be->blkif->blk_protocol = BLKIF_PROTOCOL_X86_64; | |
855 | else { | |
856 | xenbus_dev_fatal(dev, err, "unknown fe protocol %s", protocol); | |
857 | return -1; | |
858 | } | |
0a8704a5 | 859 | err = xenbus_gather(XBT_NIL, dev->otherend, |
cb5bd4d1 | 860 | "feature-persistent", "%u", |
0a8704a5 RPM |
861 | &pers_grants, NULL); |
862 | if (err) | |
863 | pers_grants = 0; | |
864 | ||
865 | be->blkif->vbd.feature_gnt_persistent = pers_grants; | |
866 | be->blkif->vbd.overflow_max_grants = 0; | |
867 | ||
868 | pr_info(DRV_PFX "ring-ref %ld, event-channel %d, protocol %d (%s) %s\n", | |
869 | ring_ref, evtchn, be->blkif->blk_protocol, protocol, | |
870 | pers_grants ? "persistent grants" : ""); | |
4d05a28d KRW |
871 | |
872 | /* Map the shared frame, irq etc. */ | |
8b6bf747 | 873 | err = xen_blkif_map(be->blkif, ring_ref, evtchn); |
4d05a28d KRW |
874 | if (err) { |
875 | xenbus_dev_fatal(dev, err, "mapping ring-ref %lu port %u", | |
876 | ring_ref, evtchn); | |
877 | return err; | |
878 | } | |
879 | ||
880 | return 0; | |
881 | } | |
882 | ||
883 | ||
884 | /* ** Driver Registration ** */ | |
885 | ||
886 | ||
8b6bf747 | 887 | static const struct xenbus_device_id xen_blkbk_ids[] = { |
4d05a28d KRW |
888 | { "vbd" }, |
889 | { "" } | |
890 | }; | |
891 | ||
892 | ||
73db144b | 893 | static DEFINE_XENBUS_DRIVER(xen_blkbk, , |
8b6bf747 KRW |
894 | .probe = xen_blkbk_probe, |
895 | .remove = xen_blkbk_remove, | |
4d05a28d | 896 | .otherend_changed = frontend_changed |
73db144b | 897 | ); |
4d05a28d KRW |
898 | |
899 | ||
8b6bf747 | 900 | int xen_blkif_xenbus_init(void) |
4d05a28d | 901 | { |
73db144b | 902 | return xenbus_register_backend(&xen_blkbk_driver); |
4d05a28d | 903 | } |