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Commit | Line | Data |
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c942fddf | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
4d05a28d KRW |
2 | /* Xenbus code for blkif backend |
3 | Copyright (C) 2005 Rusty Russell <rusty@rustcorp.com.au> | |
4 | Copyright (C) 2005 XenSource Ltd | |
5 | ||
4d05a28d | 6 | |
4d05a28d KRW |
7 | */ |
8 | ||
77387b82 TC |
9 | #define pr_fmt(fmt) "xen-blkback: " fmt |
10 | ||
4d05a28d KRW |
11 | #include <stdarg.h> |
12 | #include <linux/module.h> | |
13 | #include <linux/kthread.h> | |
ee9ff853 KRW |
14 | #include <xen/events.h> |
15 | #include <xen/grant_table.h> | |
4d05a28d KRW |
16 | #include "common.h" |
17 | ||
fa3184b8 | 18 | /* On the XenBus the max length of 'ring-ref%u'. */ |
86839c56 | 19 | #define RINGREF_NAME_LEN (20) |
1375590d | 20 | |
d6091b21 | 21 | struct backend_info { |
01f37f2d | 22 | struct xenbus_device *dev; |
51854322 | 23 | struct xen_blkif *blkif; |
01f37f2d KRW |
24 | struct xenbus_watch backend_watch; |
25 | unsigned major; | |
26 | unsigned minor; | |
27 | char *mode; | |
4d05a28d KRW |
28 | }; |
29 | ||
8b6bf747 | 30 | static struct kmem_cache *xen_blkif_cachep; |
4d05a28d KRW |
31 | static void connect(struct backend_info *); |
32 | static int connect_ring(struct backend_info *); | |
5584ea25 JG |
33 | static void backend_changed(struct xenbus_watch *, const char *, |
34 | const char *); | |
814d04e7 VP |
35 | static void xen_blkif_free(struct xen_blkif *blkif); |
36 | static void xen_vbd_free(struct xen_vbd *vbd); | |
4d05a28d | 37 | |
8b6bf747 | 38 | struct xenbus_device *xen_blkbk_xenbus(struct backend_info *be) |
98e036a3 JF |
39 | { |
40 | return be->dev; | |
41 | } | |
42 | ||
814d04e7 VP |
43 | /* |
44 | * The last request could free the device from softirq context and | |
45 | * xen_blkif_free() can sleep. | |
46 | */ | |
47 | static void xen_blkif_deferred_free(struct work_struct *work) | |
48 | { | |
49 | struct xen_blkif *blkif; | |
50 | ||
51 | blkif = container_of(work, struct xen_blkif, free_work); | |
52 | xen_blkif_free(blkif); | |
53 | } | |
54 | ||
30fd1502 | 55 | static int blkback_name(struct xen_blkif *blkif, char *buf) |
4d05a28d KRW |
56 | { |
57 | char *devpath, *devname; | |
58 | struct xenbus_device *dev = blkif->be->dev; | |
59 | ||
60 | devpath = xenbus_read(XBT_NIL, dev->nodename, "dev", NULL); | |
61 | if (IS_ERR(devpath)) | |
62 | return PTR_ERR(devpath); | |
63 | ||
d6091b21 KRW |
64 | devname = strstr(devpath, "/dev/"); |
65 | if (devname != NULL) | |
4d05a28d KRW |
66 | devname += strlen("/dev/"); |
67 | else | |
68 | devname = devpath; | |
69 | ||
fa3184b8 | 70 | snprintf(buf, TASK_COMM_LEN, "%d.%s", blkif->domid, devname); |
4d05a28d KRW |
71 | kfree(devpath); |
72 | ||
73 | return 0; | |
74 | } | |
75 | ||
30fd1502 | 76 | static void xen_update_blkif_status(struct xen_blkif *blkif) |
4d05a28d KRW |
77 | { |
78 | int err; | |
fa3184b8 | 79 | char name[TASK_COMM_LEN]; |
2fb1ef4f KRW |
80 | struct xen_blkif_ring *ring; |
81 | int i; | |
4d05a28d KRW |
82 | |
83 | /* Not ready to connect? */ | |
2fb1ef4f | 84 | if (!blkif->rings || !blkif->rings[0].irq || !blkif->vbd.bdev) |
4d05a28d KRW |
85 | return; |
86 | ||
87 | /* Already connected? */ | |
88 | if (blkif->be->dev->state == XenbusStateConnected) | |
89 | return; | |
90 | ||
91 | /* Attempt to connect: exit if we fail to. */ | |
92 | connect(blkif->be); | |
93 | if (blkif->be->dev->state != XenbusStateConnected) | |
94 | return; | |
95 | ||
96 | err = blkback_name(blkif, name); | |
97 | if (err) { | |
98 | xenbus_dev_error(blkif->be->dev, err, "get blkback dev name"); | |
99 | return; | |
100 | } | |
101 | ||
cbf46290 CL |
102 | err = filemap_write_and_wait(blkif->vbd.bdev->bd_inode->i_mapping); |
103 | if (err) { | |
104 | xenbus_dev_error(blkif->be->dev, err, "block flush"); | |
105 | return; | |
106 | } | |
107 | invalidate_inode_pages2(blkif->vbd.bdev->bd_inode->i_mapping); | |
108 | ||
2fb1ef4f KRW |
109 | for (i = 0; i < blkif->nr_rings; i++) { |
110 | ring = &blkif->rings[i]; | |
111 | ring->xenblkd = kthread_run(xen_blkif_schedule, ring, "%s-%d", name, i); | |
112 | if (IS_ERR(ring->xenblkd)) { | |
113 | err = PTR_ERR(ring->xenblkd); | |
114 | ring->xenblkd = NULL; | |
115 | xenbus_dev_fatal(blkif->be->dev, err, | |
116 | "start %s-%d xenblkd", name, i); | |
117 | goto out; | |
118 | } | |
119 | } | |
120 | return; | |
121 | ||
122 | out: | |
123 | while (--i >= 0) { | |
124 | ring = &blkif->rings[i]; | |
125 | kthread_stop(ring->xenblkd); | |
4d05a28d | 126 | } |
2fb1ef4f KRW |
127 | return; |
128 | } | |
129 | ||
130 | static int xen_blkif_alloc_rings(struct xen_blkif *blkif) | |
131 | { | |
132 | unsigned int r; | |
133 | ||
6396bb22 KC |
134 | blkif->rings = kcalloc(blkif->nr_rings, sizeof(struct xen_blkif_ring), |
135 | GFP_KERNEL); | |
2fb1ef4f KRW |
136 | if (!blkif->rings) |
137 | return -ENOMEM; | |
138 | ||
139 | for (r = 0; r < blkif->nr_rings; r++) { | |
140 | struct xen_blkif_ring *ring = &blkif->rings[r]; | |
141 | ||
142 | spin_lock_init(&ring->blk_ring_lock); | |
143 | init_waitqueue_head(&ring->wq); | |
144 | INIT_LIST_HEAD(&ring->pending_free); | |
d4bf0065 BL |
145 | INIT_LIST_HEAD(&ring->persistent_purge_list); |
146 | INIT_WORK(&ring->persistent_purge_work, xen_blkbk_unmap_purged_grants); | |
ca33479c | 147 | gnttab_page_cache_init(&ring->free_pages); |
2fb1ef4f KRW |
148 | |
149 | spin_lock_init(&ring->pending_free_lock); | |
150 | init_waitqueue_head(&ring->pending_free_wq); | |
151 | init_waitqueue_head(&ring->shutdown_wq); | |
152 | ring->blkif = blkif; | |
db6fbc10 | 153 | ring->st_print = jiffies; |
46464411 | 154 | ring->active = true; |
2fb1ef4f KRW |
155 | } |
156 | ||
157 | return 0; | |
4d05a28d KRW |
158 | } |
159 | ||
30fd1502 | 160 | static struct xen_blkif *xen_blkif_alloc(domid_t domid) |
ee9ff853 | 161 | { |
30fd1502 | 162 | struct xen_blkif *blkif; |
ee9ff853 | 163 | |
402b27f9 | 164 | BUILD_BUG_ON(MAX_INDIRECT_PAGES > BLKIF_MAX_INDIRECT_PAGES_PER_REQUEST); |
ee9ff853 | 165 | |
654dbef2 | 166 | blkif = kmem_cache_zalloc(xen_blkif_cachep, GFP_KERNEL); |
ee9ff853 KRW |
167 | if (!blkif) |
168 | return ERR_PTR(-ENOMEM); | |
169 | ||
ee9ff853 | 170 | blkif->domid = domid; |
ee9ff853 | 171 | atomic_set(&blkif->refcnt, 1); |
29bde093 | 172 | init_completion(&blkif->drain_complete); |
fa2ac657 PD |
173 | |
174 | /* | |
175 | * Because freeing back to the cache may be deferred, it is not | |
176 | * safe to unload the module (and hence destroy the cache) until | |
177 | * this has completed. To prevent premature unloading, take an | |
178 | * extra module reference here and release only when the object | |
179 | * has been freed back to the cache. | |
180 | */ | |
181 | __module_get(THIS_MODULE); | |
59795700 | 182 | INIT_WORK(&blkif->free_work, xen_blkif_deferred_free); |
ee9ff853 KRW |
183 | |
184 | return blkif; | |
185 | } | |
186 | ||
59795700 | 187 | static int xen_blkif_map(struct xen_blkif_ring *ring, grant_ref_t *gref, |
86839c56 | 188 | unsigned int nr_grefs, unsigned int evtchn) |
ee9ff853 KRW |
189 | { |
190 | int err; | |
59795700 | 191 | struct xen_blkif *blkif = ring->blkif; |
f4eef1b6 PD |
192 | const struct blkif_common_sring *sring_common; |
193 | RING_IDX rsp_prod, req_prod; | |
194 | unsigned int size; | |
ee9ff853 KRW |
195 | |
196 | /* Already connected through? */ | |
59795700 | 197 | if (ring->irq) |
ee9ff853 KRW |
198 | return 0; |
199 | ||
86839c56 | 200 | err = xenbus_map_ring_valloc(blkif->be->dev, gref, nr_grefs, |
59795700 | 201 | &ring->blk_ring); |
2d073846 | 202 | if (err < 0) |
ee9ff853 | 203 | return err; |
ee9ff853 | 204 | |
f4eef1b6 PD |
205 | sring_common = (struct blkif_common_sring *)ring->blk_ring; |
206 | rsp_prod = READ_ONCE(sring_common->rsp_prod); | |
207 | req_prod = READ_ONCE(sring_common->req_prod); | |
208 | ||
ee9ff853 KRW |
209 | switch (blkif->blk_protocol) { |
210 | case BLKIF_PROTOCOL_NATIVE: | |
211 | { | |
f4eef1b6 PD |
212 | struct blkif_sring *sring_native = |
213 | (struct blkif_sring *)ring->blk_ring; | |
214 | ||
215 | BACK_RING_ATTACH(&ring->blk_rings.native, sring_native, | |
216 | rsp_prod, XEN_PAGE_SIZE * nr_grefs); | |
217 | size = __RING_SIZE(sring_native, XEN_PAGE_SIZE * nr_grefs); | |
ee9ff853 KRW |
218 | break; |
219 | } | |
220 | case BLKIF_PROTOCOL_X86_32: | |
221 | { | |
f4eef1b6 PD |
222 | struct blkif_x86_32_sring *sring_x86_32 = |
223 | (struct blkif_x86_32_sring *)ring->blk_ring; | |
224 | ||
225 | BACK_RING_ATTACH(&ring->blk_rings.x86_32, sring_x86_32, | |
226 | rsp_prod, XEN_PAGE_SIZE * nr_grefs); | |
227 | size = __RING_SIZE(sring_x86_32, XEN_PAGE_SIZE * nr_grefs); | |
ee9ff853 KRW |
228 | break; |
229 | } | |
230 | case BLKIF_PROTOCOL_X86_64: | |
231 | { | |
f4eef1b6 PD |
232 | struct blkif_x86_64_sring *sring_x86_64 = |
233 | (struct blkif_x86_64_sring *)ring->blk_ring; | |
234 | ||
235 | BACK_RING_ATTACH(&ring->blk_rings.x86_64, sring_x86_64, | |
236 | rsp_prod, XEN_PAGE_SIZE * nr_grefs); | |
237 | size = __RING_SIZE(sring_x86_64, XEN_PAGE_SIZE * nr_grefs); | |
ee9ff853 KRW |
238 | break; |
239 | } | |
240 | default: | |
241 | BUG(); | |
242 | } | |
243 | ||
f4eef1b6 PD |
244 | err = -EIO; |
245 | if (req_prod - rsp_prod > size) | |
246 | goto fail; | |
247 | ||
01263a1f JG |
248 | err = bind_interdomain_evtchn_to_irqhandler_lateeoi(blkif->domid, |
249 | evtchn, xen_blkif_be_int, 0, "blkif-backend", ring); | |
f4eef1b6 PD |
250 | if (err < 0) |
251 | goto fail; | |
59795700 | 252 | ring->irq = err; |
ee9ff853 KRW |
253 | |
254 | return 0; | |
f4eef1b6 PD |
255 | |
256 | fail: | |
257 | xenbus_unmap_ring_vfree(blkif->be->dev, ring->blk_ring); | |
258 | ring->blk_rings.common.sring = NULL; | |
259 | return err; | |
ee9ff853 KRW |
260 | } |
261 | ||
814d04e7 | 262 | static int xen_blkif_disconnect(struct xen_blkif *blkif) |
ee9ff853 | 263 | { |
f929d42c | 264 | struct pending_req *req, *n; |
2fb1ef4f | 265 | unsigned int j, r; |
dc52d783 | 266 | bool busy = false; |
f929d42c | 267 | |
2fb1ef4f KRW |
268 | for (r = 0; r < blkif->nr_rings; r++) { |
269 | struct xen_blkif_ring *ring = &blkif->rings[r]; | |
270 | unsigned int i = 0; | |
ee9ff853 | 271 | |
46464411 JG |
272 | if (!ring->active) |
273 | continue; | |
274 | ||
2fb1ef4f KRW |
275 | if (ring->xenblkd) { |
276 | kthread_stop(ring->xenblkd); | |
1c728719 | 277 | ring->xenblkd = NULL; |
2fb1ef4f | 278 | wake_up(&ring->shutdown_wq); |
2fb1ef4f | 279 | } |
ee9ff853 | 280 | |
2fb1ef4f KRW |
281 | /* The above kthread_stop() guarantees that at this point we |
282 | * don't have any discard_io or other_io requests. So, checking | |
283 | * for inflight IO is enough. | |
284 | */ | |
dc52d783 AL |
285 | if (atomic_read(&ring->inflight) > 0) { |
286 | busy = true; | |
287 | continue; | |
288 | } | |
ee9ff853 | 289 | |
2fb1ef4f KRW |
290 | if (ring->irq) { |
291 | unbind_from_irqhandler(ring->irq, ring); | |
292 | ring->irq = 0; | |
293 | } | |
814d04e7 | 294 | |
2fb1ef4f KRW |
295 | if (ring->blk_rings.common.sring) { |
296 | xenbus_unmap_ring_vfree(blkif->be->dev, ring->blk_ring); | |
297 | ring->blk_rings.common.sring = NULL; | |
298 | } | |
12ea7296 | 299 | |
2fb1ef4f KRW |
300 | /* Remove all persistent grants and the cache of ballooned pages. */ |
301 | xen_blkbk_free_caches(ring); | |
f929d42c | 302 | |
2fb1ef4f KRW |
303 | /* Check that there is no request in use */ |
304 | list_for_each_entry_safe(req, n, &ring->pending_free, free_list) { | |
305 | list_del(&req->free_list); | |
f929d42c | 306 | |
2fb1ef4f KRW |
307 | for (j = 0; j < MAX_INDIRECT_SEGMENTS; j++) |
308 | kfree(req->segments[j]); | |
f929d42c | 309 | |
2fb1ef4f KRW |
310 | for (j = 0; j < MAX_INDIRECT_PAGES; j++) |
311 | kfree(req->indirect_pages[j]); | |
f929d42c | 312 | |
2fb1ef4f KRW |
313 | kfree(req); |
314 | i++; | |
315 | } | |
316 | ||
d4bf0065 BL |
317 | BUG_ON(atomic_read(&ring->persistent_gnt_in_use) != 0); |
318 | BUG_ON(!list_empty(&ring->persistent_purge_list)); | |
319 | BUG_ON(!RB_EMPTY_ROOT(&ring->persistent_gnts)); | |
ca33479c | 320 | BUG_ON(ring->free_pages.num_pages != 0); |
d4bf0065 | 321 | BUG_ON(ring->persistent_gnt_c != 0); |
2fb1ef4f | 322 | WARN_ON(i != (XEN_BLKIF_REQS_PER_PAGE * blkif->nr_ring_pages)); |
46464411 | 323 | ring->active = false; |
2fb1ef4f | 324 | } |
dc52d783 AL |
325 | if (busy) |
326 | return -EBUSY; | |
327 | ||
f929d42c | 328 | blkif->nr_ring_pages = 0; |
93bb277f BL |
329 | /* |
330 | * blkif->rings was allocated in connect_ring, so we should free it in | |
331 | * here. | |
332 | */ | |
333 | kfree(blkif->rings); | |
334 | blkif->rings = NULL; | |
335 | blkif->nr_rings = 0; | |
f929d42c | 336 | |
814d04e7 | 337 | return 0; |
ee9ff853 KRW |
338 | } |
339 | ||
2911758f | 340 | static void xen_blkif_free(struct xen_blkif *blkif) |
ee9ff853 | 341 | { |
71df1d7c | 342 | WARN_ON(xen_blkif_disconnect(blkif)); |
814d04e7 | 343 | xen_vbd_free(&blkif->vbd); |
71df1d7c JG |
344 | kfree(blkif->be->mode); |
345 | kfree(blkif->be); | |
bf0720c4 | 346 | |
ef753411 | 347 | /* Make sure everything is drained before shutting down */ |
8b6bf747 | 348 | kmem_cache_free(xen_blkif_cachep, blkif); |
fa2ac657 | 349 | module_put(THIS_MODULE); |
ee9ff853 KRW |
350 | } |
351 | ||
8b6bf747 | 352 | int __init xen_blkif_interface_init(void) |
ee9ff853 | 353 | { |
8b6bf747 | 354 | xen_blkif_cachep = kmem_cache_create("blkif_cache", |
30fd1502 | 355 | sizeof(struct xen_blkif), |
8b6bf747 KRW |
356 | 0, 0, NULL); |
357 | if (!xen_blkif_cachep) | |
ee9ff853 KRW |
358 | return -ENOMEM; |
359 | ||
360 | return 0; | |
361 | } | |
4d05a28d | 362 | |
14855954 PD |
363 | void xen_blkif_interface_fini(void) |
364 | { | |
365 | kmem_cache_destroy(xen_blkif_cachep); | |
366 | xen_blkif_cachep = NULL; | |
367 | } | |
368 | ||
a1397fa3 | 369 | /* |
4d05a28d KRW |
370 | * sysfs interface for VBD I/O requests |
371 | */ | |
372 | ||
db6fbc10 | 373 | #define VBD_SHOW_ALLRING(name, format) \ |
4d05a28d KRW |
374 | static ssize_t show_##name(struct device *_dev, \ |
375 | struct device_attribute *attr, \ | |
376 | char *buf) \ | |
377 | { \ | |
378 | struct xenbus_device *dev = to_xenbus_device(_dev); \ | |
5cf6e4f6 | 379 | struct backend_info *be = dev_get_drvdata(&dev->dev); \ |
db6fbc10 BL |
380 | struct xen_blkif *blkif = be->blkif; \ |
381 | unsigned int i; \ | |
382 | unsigned long long result = 0; \ | |
4d05a28d | 383 | \ |
db6fbc10 BL |
384 | if (!blkif->rings) \ |
385 | goto out; \ | |
386 | \ | |
387 | for (i = 0; i < blkif->nr_rings; i++) { \ | |
388 | struct xen_blkif_ring *ring = &blkif->rings[i]; \ | |
389 | \ | |
390 | result += ring->st_##name; \ | |
391 | } \ | |
392 | \ | |
393 | out: \ | |
394 | return sprintf(buf, format, result); \ | |
4d05a28d | 395 | } \ |
5657a819 | 396 | static DEVICE_ATTR(name, 0444, show_##name, NULL) |
4d05a28d | 397 | |
db6fbc10 BL |
398 | VBD_SHOW_ALLRING(oo_req, "%llu\n"); |
399 | VBD_SHOW_ALLRING(rd_req, "%llu\n"); | |
400 | VBD_SHOW_ALLRING(wr_req, "%llu\n"); | |
401 | VBD_SHOW_ALLRING(f_req, "%llu\n"); | |
402 | VBD_SHOW_ALLRING(ds_req, "%llu\n"); | |
403 | VBD_SHOW_ALLRING(rd_sect, "%llu\n"); | |
404 | VBD_SHOW_ALLRING(wr_sect, "%llu\n"); | |
4d05a28d | 405 | |
3d814731 | 406 | static struct attribute *xen_vbdstat_attrs[] = { |
4d05a28d KRW |
407 | &dev_attr_oo_req.attr, |
408 | &dev_attr_rd_req.attr, | |
409 | &dev_attr_wr_req.attr, | |
24f567f9 | 410 | &dev_attr_f_req.attr, |
b3cb0d6a | 411 | &dev_attr_ds_req.attr, |
4d05a28d KRW |
412 | &dev_attr_rd_sect.attr, |
413 | &dev_attr_wr_sect.attr, | |
414 | NULL | |
415 | }; | |
416 | ||
53043948 | 417 | static const struct attribute_group xen_vbdstat_group = { |
4d05a28d | 418 | .name = "statistics", |
3d814731 | 419 | .attrs = xen_vbdstat_attrs, |
4d05a28d KRW |
420 | }; |
421 | ||
db6fbc10 BL |
422 | #define VBD_SHOW(name, format, args...) \ |
423 | static ssize_t show_##name(struct device *_dev, \ | |
424 | struct device_attribute *attr, \ | |
425 | char *buf) \ | |
426 | { \ | |
427 | struct xenbus_device *dev = to_xenbus_device(_dev); \ | |
428 | struct backend_info *be = dev_get_drvdata(&dev->dev); \ | |
429 | \ | |
430 | return sprintf(buf, format, ##args); \ | |
431 | } \ | |
5657a819 | 432 | static DEVICE_ATTR(name, 0444, show_##name, NULL) |
db6fbc10 | 433 | |
4d05a28d KRW |
434 | VBD_SHOW(physical_device, "%x:%x\n", be->major, be->minor); |
435 | VBD_SHOW(mode, "%s\n", be->mode); | |
436 | ||
2911758f | 437 | static int xenvbd_sysfs_addif(struct xenbus_device *dev) |
4d05a28d KRW |
438 | { |
439 | int error; | |
440 | ||
441 | error = device_create_file(&dev->dev, &dev_attr_physical_device); | |
d6091b21 | 442 | if (error) |
4d05a28d KRW |
443 | goto fail1; |
444 | ||
445 | error = device_create_file(&dev->dev, &dev_attr_mode); | |
446 | if (error) | |
447 | goto fail2; | |
448 | ||
3d814731 | 449 | error = sysfs_create_group(&dev->dev.kobj, &xen_vbdstat_group); |
4d05a28d KRW |
450 | if (error) |
451 | goto fail3; | |
452 | ||
453 | return 0; | |
454 | ||
3d814731 | 455 | fail3: sysfs_remove_group(&dev->dev.kobj, &xen_vbdstat_group); |
4d05a28d KRW |
456 | fail2: device_remove_file(&dev->dev, &dev_attr_mode); |
457 | fail1: device_remove_file(&dev->dev, &dev_attr_physical_device); | |
458 | return error; | |
459 | } | |
460 | ||
2911758f | 461 | static void xenvbd_sysfs_delif(struct xenbus_device *dev) |
4d05a28d | 462 | { |
3d814731 | 463 | sysfs_remove_group(&dev->dev.kobj, &xen_vbdstat_group); |
4d05a28d KRW |
464 | device_remove_file(&dev->dev, &dev_attr_mode); |
465 | device_remove_file(&dev->dev, &dev_attr_physical_device); | |
466 | } | |
467 | ||
3d814731 | 468 | static void xen_vbd_free(struct xen_vbd *vbd) |
42c7841d KRW |
469 | { |
470 | if (vbd->bdev) | |
471 | blkdev_put(vbd->bdev, vbd->readonly ? FMODE_READ : FMODE_WRITE); | |
472 | vbd->bdev = NULL; | |
473 | } | |
474 | ||
aac8a70d SP |
475 | /* Enable the persistent grants feature. */ |
476 | static bool feature_persistent = true; | |
477 | module_param(feature_persistent, bool, 0644); | |
478 | MODULE_PARM_DESC(feature_persistent, | |
479 | "Enables the persistent grants feature"); | |
480 | ||
3d814731 KRW |
481 | static int xen_vbd_create(struct xen_blkif *blkif, blkif_vdev_t handle, |
482 | unsigned major, unsigned minor, int readonly, | |
483 | int cdrom) | |
42c7841d | 484 | { |
3d814731 | 485 | struct xen_vbd *vbd; |
42c7841d | 486 | struct block_device *bdev; |
24f567f9 | 487 | struct request_queue *q; |
42c7841d KRW |
488 | |
489 | vbd = &blkif->vbd; | |
490 | vbd->handle = handle; | |
491 | vbd->readonly = readonly; | |
492 | vbd->type = 0; | |
493 | ||
494 | vbd->pdevice = MKDEV(major, minor); | |
495 | ||
496 | bdev = blkdev_get_by_dev(vbd->pdevice, vbd->readonly ? | |
497 | FMODE_READ : FMODE_WRITE, NULL); | |
498 | ||
499 | if (IS_ERR(bdev)) { | |
77387b82 | 500 | pr_warn("xen_vbd_create: device %08x could not be opened\n", |
42c7841d KRW |
501 | vbd->pdevice); |
502 | return -ENOENT; | |
503 | } | |
504 | ||
505 | vbd->bdev = bdev; | |
42c7841d | 506 | if (vbd->bdev->bd_disk == NULL) { |
77387b82 | 507 | pr_warn("xen_vbd_create: device %08x doesn't exist\n", |
42c7841d | 508 | vbd->pdevice); |
3d814731 | 509 | xen_vbd_free(vbd); |
42c7841d KRW |
510 | return -ENOENT; |
511 | } | |
6464920a | 512 | vbd->size = vbd_sz(vbd); |
42c7841d KRW |
513 | |
514 | if (vbd->bdev->bd_disk->flags & GENHD_FL_CD || cdrom) | |
515 | vbd->type |= VDISK_CDROM; | |
516 | if (vbd->bdev->bd_disk->flags & GENHD_FL_REMOVABLE) | |
517 | vbd->type |= VDISK_REMOVABLE; | |
518 | ||
24f567f9 | 519 | q = bdev_get_queue(bdev); |
c888a8f9 | 520 | if (q && test_bit(QUEUE_FLAG_WC, &q->queue_flags)) |
24f567f9 KRW |
521 | vbd->flush_support = true; |
522 | ||
288dab8a | 523 | if (q && blk_queue_secure_erase(q)) |
5ea42986 KRW |
524 | vbd->discard_secure = true; |
525 | ||
aac8a70d SP |
526 | vbd->feature_gnt_persistent = feature_persistent; |
527 | ||
77387b82 | 528 | pr_debug("Successful creation of handle=%04x (dom=%u)\n", |
42c7841d KRW |
529 | handle, blkif->domid); |
530 | return 0; | |
531 | } | |
8557bbe5 | 532 | |
8b6bf747 | 533 | static int xen_blkbk_remove(struct xenbus_device *dev) |
4d05a28d | 534 | { |
5cf6e4f6 | 535 | struct backend_info *be = dev_get_drvdata(&dev->dev); |
4d05a28d | 536 | |
77387b82 | 537 | pr_debug("%s %p %d\n", __func__, dev, dev->otherend_id); |
4d05a28d KRW |
538 | |
539 | if (be->major || be->minor) | |
540 | xenvbd_sysfs_delif(dev); | |
541 | ||
542 | if (be->backend_watch.node) { | |
543 | unregister_xenbus_watch(&be->backend_watch); | |
544 | kfree(be->backend_watch.node); | |
545 | be->backend_watch.node = NULL; | |
546 | } | |
547 | ||
814d04e7 VP |
548 | dev_set_drvdata(&dev->dev, NULL); |
549 | ||
2d4456c7 | 550 | if (be->blkif) { |
8b6bf747 | 551 | xen_blkif_disconnect(be->blkif); |
4d05a28d | 552 | |
2d4456c7 GS |
553 | /* Put the reference we set in xen_blkif_alloc(). */ |
554 | xen_blkif_put(be->blkif); | |
555 | } | |
556 | ||
4d05a28d KRW |
557 | return 0; |
558 | } | |
559 | ||
24f567f9 KRW |
560 | int xen_blkbk_flush_diskcache(struct xenbus_transaction xbt, |
561 | struct backend_info *be, int state) | |
4d05a28d KRW |
562 | { |
563 | struct xenbus_device *dev = be->dev; | |
564 | int err; | |
565 | ||
24f567f9 | 566 | err = xenbus_printf(xbt, dev->nodename, "feature-flush-cache", |
4d05a28d KRW |
567 | "%d", state); |
568 | if (err) | |
3389bb8b | 569 | dev_warn(&dev->dev, "writing feature-flush-cache (%d)", err); |
4d05a28d KRW |
570 | |
571 | return err; | |
572 | } | |
573 | ||
3389bb8b | 574 | static void xen_blkbk_discard(struct xenbus_transaction xbt, struct backend_info *be) |
b3cb0d6a LD |
575 | { |
576 | struct xenbus_device *dev = be->dev; | |
577 | struct xen_blkif *blkif = be->blkif; | |
b3cb0d6a | 578 | int err; |
8235777b | 579 | int state = 0; |
4dae7670 KRW |
580 | struct block_device *bdev = be->blkif->vbd.bdev; |
581 | struct request_queue *q = bdev_get_queue(bdev); | |
582 | ||
8235777b | 583 | if (!xenbus_read_unsigned(dev->nodename, "discard-enable", 1)) |
c926b701 OH |
584 | return; |
585 | ||
4dae7670 KRW |
586 | if (blk_queue_discard(q)) { |
587 | err = xenbus_printf(xbt, dev->nodename, | |
588 | "discard-granularity", "%u", | |
589 | q->limits.discard_granularity); | |
590 | if (err) { | |
3389bb8b KRW |
591 | dev_warn(&dev->dev, "writing discard-granularity (%d)", err); |
592 | return; | |
4dae7670 KRW |
593 | } |
594 | err = xenbus_printf(xbt, dev->nodename, | |
595 | "discard-alignment", "%u", | |
596 | q->limits.discard_alignment); | |
597 | if (err) { | |
3389bb8b KRW |
598 | dev_warn(&dev->dev, "writing discard-alignment (%d)", err); |
599 | return; | |
b3cb0d6a | 600 | } |
4dae7670 KRW |
601 | state = 1; |
602 | /* Optional. */ | |
603 | err = xenbus_printf(xbt, dev->nodename, | |
604 | "discard-secure", "%d", | |
605 | blkif->vbd.discard_secure); | |
606 | if (err) { | |
a71e23d9 | 607 | dev_warn(&dev->dev, "writing discard-secure (%d)", err); |
3389bb8b | 608 | return; |
b3cb0d6a | 609 | } |
b3cb0d6a | 610 | } |
b3cb0d6a LD |
611 | err = xenbus_printf(xbt, dev->nodename, "feature-discard", |
612 | "%d", state); | |
613 | if (err) | |
3389bb8b | 614 | dev_warn(&dev->dev, "writing feature-discard (%d)", err); |
b3cb0d6a | 615 | } |
8557bbe5 | 616 | |
29bde093 KRW |
617 | int xen_blkbk_barrier(struct xenbus_transaction xbt, |
618 | struct backend_info *be, int state) | |
619 | { | |
620 | struct xenbus_device *dev = be->dev; | |
621 | int err; | |
622 | ||
623 | err = xenbus_printf(xbt, dev->nodename, "feature-barrier", | |
624 | "%d", state); | |
625 | if (err) | |
3389bb8b | 626 | dev_warn(&dev->dev, "writing feature-barrier (%d)", err); |
29bde093 KRW |
627 | |
628 | return err; | |
629 | } | |
b3cb0d6a | 630 | |
01f37f2d | 631 | /* |
4d05a28d KRW |
632 | * Entry point to this code when a new device is created. Allocate the basic |
633 | * structures, and watch the store waiting for the hotplug scripts to tell us | |
634 | * the device's physical major and minor numbers. Switch to InitWait. | |
635 | */ | |
8b6bf747 KRW |
636 | static int xen_blkbk_probe(struct xenbus_device *dev, |
637 | const struct xenbus_device_id *id) | |
4d05a28d KRW |
638 | { |
639 | int err; | |
640 | struct backend_info *be = kzalloc(sizeof(struct backend_info), | |
641 | GFP_KERNEL); | |
77387b82 TC |
642 | |
643 | /* match the pr_debug in xen_blkbk_remove */ | |
644 | pr_debug("%s %p %d\n", __func__, dev, dev->otherend_id); | |
645 | ||
4d05a28d KRW |
646 | if (!be) { |
647 | xenbus_dev_fatal(dev, -ENOMEM, | |
648 | "allocating backend structure"); | |
649 | return -ENOMEM; | |
650 | } | |
651 | be->dev = dev; | |
5cf6e4f6 | 652 | dev_set_drvdata(&dev->dev, be); |
4d05a28d | 653 | |
8b6bf747 | 654 | be->blkif = xen_blkif_alloc(dev->otherend_id); |
4d05a28d KRW |
655 | if (IS_ERR(be->blkif)) { |
656 | err = PTR_ERR(be->blkif); | |
657 | be->blkif = NULL; | |
658 | xenbus_dev_fatal(dev, err, "creating block interface"); | |
659 | goto fail; | |
660 | } | |
661 | ||
5a705845 JB |
662 | err = xenbus_printf(XBT_NIL, dev->nodename, |
663 | "feature-max-indirect-segments", "%u", | |
664 | MAX_INDIRECT_SEGMENTS); | |
665 | if (err) | |
666 | dev_warn(&dev->dev, | |
667 | "writing %s/feature-max-indirect-segments (%d)", | |
668 | dev->nodename, err); | |
669 | ||
d62d8600 BL |
670 | /* Multi-queue: advertise how many queues are supported by us.*/ |
671 | err = xenbus_printf(XBT_NIL, dev->nodename, | |
672 | "multi-queue-max-queues", "%u", xenblk_max_queues); | |
673 | if (err) | |
674 | pr_warn("Error writing multi-queue-max-queues\n"); | |
675 | ||
4d05a28d KRW |
676 | /* setup back pointer */ |
677 | be->blkif->be = be; | |
678 | ||
2e85d32b SP |
679 | err = xenbus_watch_pathfmt(dev, &be->backend_watch, NULL, |
680 | backend_changed, | |
88122933 | 681 | "%s/%s", dev->nodename, "physical-device"); |
4d05a28d KRW |
682 | if (err) |
683 | goto fail; | |
684 | ||
86839c56 BL |
685 | err = xenbus_printf(XBT_NIL, dev->nodename, "max-ring-page-order", "%u", |
686 | xen_blkif_max_ring_order); | |
687 | if (err) | |
688 | pr_warn("%s write out 'max-ring-page-order' failed\n", __func__); | |
689 | ||
4d05a28d KRW |
690 | err = xenbus_switch_state(dev, XenbusStateInitWait); |
691 | if (err) | |
692 | goto fail; | |
693 | ||
694 | return 0; | |
695 | ||
696 | fail: | |
77387b82 | 697 | pr_warn("%s failed\n", __func__); |
8b6bf747 | 698 | xen_blkbk_remove(dev); |
4d05a28d KRW |
699 | return err; |
700 | } | |
701 | ||
01f37f2d | 702 | /* |
4d05a28d KRW |
703 | * Callback received when the hotplug scripts have placed the physical-device |
704 | * node. Read it and the mode node, and create a vbd. If the frontend is | |
705 | * ready, connect. | |
706 | */ | |
707 | static void backend_changed(struct xenbus_watch *watch, | |
5584ea25 | 708 | const char *path, const char *token) |
4d05a28d KRW |
709 | { |
710 | int err; | |
711 | unsigned major; | |
712 | unsigned minor; | |
713 | struct backend_info *be | |
714 | = container_of(watch, struct backend_info, backend_watch); | |
715 | struct xenbus_device *dev = be->dev; | |
716 | int cdrom = 0; | |
9d092603 | 717 | unsigned long handle; |
4d05a28d KRW |
718 | char *device_type; |
719 | ||
77387b82 | 720 | pr_debug("%s %p %d\n", __func__, dev, dev->otherend_id); |
4d05a28d KRW |
721 | |
722 | err = xenbus_scanf(XBT_NIL, dev->nodename, "physical-device", "%x:%x", | |
723 | &major, &minor); | |
724 | if (XENBUS_EXIST_ERR(err)) { | |
01f37f2d KRW |
725 | /* |
726 | * Since this watch will fire once immediately after it is | |
727 | * registered, we expect this. Ignore it, and wait for the | |
728 | * hotplug scripts. | |
729 | */ | |
4d05a28d KRW |
730 | return; |
731 | } | |
732 | if (err != 2) { | |
733 | xenbus_dev_fatal(dev, err, "reading physical-device"); | |
734 | return; | |
735 | } | |
736 | ||
9d092603 JB |
737 | if (be->major | be->minor) { |
738 | if (be->major != major || be->minor != minor) | |
77387b82 | 739 | pr_warn("changing physical device (from %x:%x to %x:%x) not supported.\n", |
9d092603 | 740 | be->major, be->minor, major, minor); |
4d05a28d KRW |
741 | return; |
742 | } | |
743 | ||
744 | be->mode = xenbus_read(XBT_NIL, dev->nodename, "mode", NULL); | |
745 | if (IS_ERR(be->mode)) { | |
746 | err = PTR_ERR(be->mode); | |
747 | be->mode = NULL; | |
748 | xenbus_dev_fatal(dev, err, "reading mode"); | |
749 | return; | |
750 | } | |
751 | ||
752 | device_type = xenbus_read(XBT_NIL, dev->otherend, "device-type", NULL); | |
753 | if (!IS_ERR(device_type)) { | |
754 | cdrom = strcmp(device_type, "cdrom") == 0; | |
755 | kfree(device_type); | |
756 | } | |
757 | ||
9d092603 | 758 | /* Front end dir is a number, which is used as the handle. */ |
bb8e0e84 | 759 | err = kstrtoul(strrchr(dev->otherend, '/') + 1, 0, &handle); |
aea305e1 JB |
760 | if (err) { |
761 | kfree(be->mode); | |
762 | be->mode = NULL; | |
9d092603 | 763 | return; |
aea305e1 | 764 | } |
4d05a28d | 765 | |
9d092603 JB |
766 | be->major = major; |
767 | be->minor = minor; | |
4d05a28d | 768 | |
9d092603 JB |
769 | err = xen_vbd_create(be->blkif, handle, major, minor, |
770 | !strchr(be->mode, 'w'), cdrom); | |
4d05a28d | 771 | |
9d092603 JB |
772 | if (err) |
773 | xenbus_dev_fatal(dev, err, "creating vbd structure"); | |
774 | else { | |
4d05a28d KRW |
775 | err = xenvbd_sysfs_addif(dev); |
776 | if (err) { | |
3d814731 | 777 | xen_vbd_free(&be->blkif->vbd); |
4d05a28d | 778 | xenbus_dev_fatal(dev, err, "creating sysfs entries"); |
4d05a28d | 779 | } |
9d092603 | 780 | } |
4d05a28d | 781 | |
9d092603 JB |
782 | if (err) { |
783 | kfree(be->mode); | |
784 | be->mode = NULL; | |
785 | be->major = 0; | |
786 | be->minor = 0; | |
787 | } else { | |
4d05a28d | 788 | /* We're potentially connected now */ |
8b6bf747 | 789 | xen_update_blkif_status(be->blkif); |
4d05a28d KRW |
790 | } |
791 | } | |
792 | ||
01f37f2d | 793 | /* |
4d05a28d KRW |
794 | * Callback received when the frontend's state changes. |
795 | */ | |
796 | static void frontend_changed(struct xenbus_device *dev, | |
797 | enum xenbus_state frontend_state) | |
798 | { | |
5cf6e4f6 | 799 | struct backend_info *be = dev_get_drvdata(&dev->dev); |
4d05a28d KRW |
800 | int err; |
801 | ||
77387b82 | 802 | pr_debug("%s %p %s\n", __func__, dev, xenbus_strstate(frontend_state)); |
4d05a28d KRW |
803 | |
804 | switch (frontend_state) { | |
805 | case XenbusStateInitialising: | |
806 | if (dev->state == XenbusStateClosed) { | |
77387b82 | 807 | pr_info("%s: prepare for reconnect\n", dev->nodename); |
4d05a28d KRW |
808 | xenbus_switch_state(dev, XenbusStateInitWait); |
809 | } | |
810 | break; | |
811 | ||
812 | case XenbusStateInitialised: | |
813 | case XenbusStateConnected: | |
01f37f2d KRW |
814 | /* |
815 | * Ensure we connect even when two watches fire in | |
42b2aa86 | 816 | * close succession and we miss the intermediate value |
01f37f2d KRW |
817 | * of frontend_state. |
818 | */ | |
4d05a28d KRW |
819 | if (dev->state == XenbusStateConnected) |
820 | break; | |
821 | ||
01f37f2d KRW |
822 | /* |
823 | * Enforce precondition before potential leak point. | |
1bc05b0a | 824 | * xen_blkif_disconnect() is idempotent. |
313d7b00 | 825 | */ |
814d04e7 VP |
826 | err = xen_blkif_disconnect(be->blkif); |
827 | if (err) { | |
828 | xenbus_dev_fatal(dev, err, "pending I/O"); | |
829 | break; | |
830 | } | |
313d7b00 | 831 | |
4d05a28d | 832 | err = connect_ring(be); |
2d0382fa KRW |
833 | if (err) { |
834 | /* | |
835 | * Clean up so that memory resources can be used by | |
836 | * other devices. connect_ring reported already error. | |
837 | */ | |
838 | xen_blkif_disconnect(be->blkif); | |
4d05a28d | 839 | break; |
2d0382fa | 840 | } |
8b6bf747 | 841 | xen_update_blkif_status(be->blkif); |
4d05a28d KRW |
842 | break; |
843 | ||
844 | case XenbusStateClosing: | |
4d05a28d KRW |
845 | xenbus_switch_state(dev, XenbusStateClosing); |
846 | break; | |
847 | ||
848 | case XenbusStateClosed: | |
6f5986bc | 849 | xen_blkif_disconnect(be->blkif); |
4d05a28d KRW |
850 | xenbus_switch_state(dev, XenbusStateClosed); |
851 | if (xenbus_dev_is_online(dev)) | |
852 | break; | |
df561f66 | 853 | fallthrough; |
3f2c9405 | 854 | /* if not online */ |
4d05a28d | 855 | case XenbusStateUnknown: |
1bc05b0a | 856 | /* implies xen_blkif_disconnect() via xen_blkbk_remove() */ |
4d05a28d KRW |
857 | device_unregister(&dev->dev); |
858 | break; | |
859 | ||
860 | default: | |
861 | xenbus_dev_fatal(dev, -EINVAL, "saw state %d at frontend", | |
862 | frontend_state); | |
863 | break; | |
864 | } | |
865 | } | |
866 | ||
cb9369bd SP |
867 | /* Once a memory pressure is detected, squeeze free page pools for a while. */ |
868 | static unsigned int buffer_squeeze_duration_ms = 10; | |
869 | module_param_named(buffer_squeeze_duration_ms, | |
870 | buffer_squeeze_duration_ms, int, 0644); | |
871 | MODULE_PARM_DESC(buffer_squeeze_duration_ms, | |
872 | "Duration in ms to squeeze pages buffer when a memory pressure is detected"); | |
873 | ||
874 | /* | |
875 | * Callback received when the memory pressure is detected. | |
876 | */ | |
877 | static void reclaim_memory(struct xenbus_device *dev) | |
878 | { | |
879 | struct backend_info *be = dev_get_drvdata(&dev->dev); | |
880 | ||
881 | if (!be) | |
882 | return; | |
883 | be->blkif->buffer_squeeze_end = jiffies + | |
884 | msecs_to_jiffies(buffer_squeeze_duration_ms); | |
885 | } | |
886 | ||
4d05a28d KRW |
887 | /* ** Connection ** */ |
888 | ||
01f37f2d | 889 | /* |
4d05a28d KRW |
890 | * Write the physical details regarding the block device to the store, and |
891 | * switch to Connected state. | |
892 | */ | |
893 | static void connect(struct backend_info *be) | |
894 | { | |
895 | struct xenbus_transaction xbt; | |
896 | int err; | |
897 | struct xenbus_device *dev = be->dev; | |
898 | ||
77387b82 | 899 | pr_debug("%s %s\n", __func__, dev->otherend); |
4d05a28d KRW |
900 | |
901 | /* Supply the information about the device the frontend needs */ | |
902 | again: | |
903 | err = xenbus_transaction_start(&xbt); | |
904 | if (err) { | |
905 | xenbus_dev_fatal(dev, err, "starting transaction"); | |
906 | return; | |
907 | } | |
908 | ||
3389bb8b KRW |
909 | /* If we can't advertise it is OK. */ |
910 | xen_blkbk_flush_diskcache(xbt, be, be->blkif->vbd.flush_support); | |
4d05a28d | 911 | |
3389bb8b | 912 | xen_blkbk_discard(xbt, be); |
b3cb0d6a | 913 | |
3389bb8b | 914 | xen_blkbk_barrier(xbt, be, be->blkif->vbd.flush_support); |
29bde093 | 915 | |
aac8a70d SP |
916 | err = xenbus_printf(xbt, dev->nodename, "feature-persistent", "%u", |
917 | be->blkif->vbd.feature_gnt_persistent); | |
0a8704a5 RPM |
918 | if (err) { |
919 | xenbus_dev_fatal(dev, err, "writing %s/feature-persistent", | |
920 | dev->nodename); | |
921 | goto abort; | |
922 | } | |
923 | ||
4d05a28d | 924 | err = xenbus_printf(xbt, dev->nodename, "sectors", "%llu", |
42c7841d | 925 | (unsigned long long)vbd_sz(&be->blkif->vbd)); |
4d05a28d KRW |
926 | if (err) { |
927 | xenbus_dev_fatal(dev, err, "writing %s/sectors", | |
928 | dev->nodename); | |
929 | goto abort; | |
930 | } | |
931 | ||
932 | /* FIXME: use a typename instead */ | |
933 | err = xenbus_printf(xbt, dev->nodename, "info", "%u", | |
42c7841d KRW |
934 | be->blkif->vbd.type | |
935 | (be->blkif->vbd.readonly ? VDISK_READONLY : 0)); | |
4d05a28d KRW |
936 | if (err) { |
937 | xenbus_dev_fatal(dev, err, "writing %s/info", | |
938 | dev->nodename); | |
939 | goto abort; | |
940 | } | |
941 | err = xenbus_printf(xbt, dev->nodename, "sector-size", "%lu", | |
42c7841d KRW |
942 | (unsigned long) |
943 | bdev_logical_block_size(be->blkif->vbd.bdev)); | |
4d05a28d KRW |
944 | if (err) { |
945 | xenbus_dev_fatal(dev, err, "writing %s/sector-size", | |
946 | dev->nodename); | |
947 | goto abort; | |
948 | } | |
7c4d7d71 SB |
949 | err = xenbus_printf(xbt, dev->nodename, "physical-sector-size", "%u", |
950 | bdev_physical_block_size(be->blkif->vbd.bdev)); | |
951 | if (err) | |
952 | xenbus_dev_error(dev, err, "writing %s/physical-sector-size", | |
953 | dev->nodename); | |
4d05a28d KRW |
954 | |
955 | err = xenbus_transaction_end(xbt, 0); | |
956 | if (err == -EAGAIN) | |
957 | goto again; | |
958 | if (err) | |
959 | xenbus_dev_fatal(dev, err, "ending transaction"); | |
960 | ||
961 | err = xenbus_switch_state(dev, XenbusStateConnected); | |
962 | if (err) | |
08b8bfc1 | 963 | xenbus_dev_fatal(dev, err, "%s: switching to Connected state", |
4d05a28d KRW |
964 | dev->nodename); |
965 | ||
966 | return; | |
967 | abort: | |
968 | xenbus_transaction_end(xbt, 1); | |
969 | } | |
970 | ||
2fb1ef4f KRW |
971 | /* |
972 | * Each ring may have multi pages, depends on "ring-page-order". | |
973 | */ | |
974 | static int read_per_ring_refs(struct xen_blkif_ring *ring, const char *dir) | |
4d05a28d | 975 | { |
9cce2914 | 976 | unsigned int ring_ref[XENBUS_MAX_RING_GRANTS]; |
69b91ede BL |
977 | struct pending_req *req, *n; |
978 | int err, i, j; | |
2fb1ef4f KRW |
979 | struct xen_blkif *blkif = ring->blkif; |
980 | struct xenbus_device *dev = blkif->be->dev; | |
4a8c31a1 | 981 | unsigned int nr_grefs, evtchn; |
4d05a28d | 982 | |
2fb1ef4f | 983 | err = xenbus_scanf(XBT_NIL, dir, "event-channel", "%u", |
86839c56 BL |
984 | &evtchn); |
985 | if (err != 1) { | |
986 | err = -EINVAL; | |
2fb1ef4f | 987 | xenbus_dev_fatal(dev, err, "reading %s/event-channel", dir); |
4d05a28d KRW |
988 | return err; |
989 | } | |
86839c56 | 990 | |
4a8c31a1 DZ |
991 | nr_grefs = blkif->nr_ring_pages; |
992 | ||
993 | if (unlikely(!nr_grefs)) { | |
994 | WARN_ON(true); | |
995 | return -EINVAL; | |
996 | } | |
997 | ||
998 | for (i = 0; i < nr_grefs; i++) { | |
999 | char ring_ref_name[RINGREF_NAME_LEN]; | |
1000 | ||
6211a3f4 PD |
1001 | if (blkif->multi_ref) |
1002 | snprintf(ring_ref_name, RINGREF_NAME_LEN, "ring-ref%u", i); | |
1003 | else { | |
1004 | WARN_ON(i != 0); | |
1005 | snprintf(ring_ref_name, RINGREF_NAME_LEN, "ring-ref"); | |
1006 | } | |
1007 | ||
4a8c31a1 DZ |
1008 | err = xenbus_scanf(XBT_NIL, dir, ring_ref_name, |
1009 | "%u", &ring_ref[i]); | |
1010 | ||
86839c56 BL |
1011 | if (err != 1) { |
1012 | err = -EINVAL; | |
4a8c31a1 DZ |
1013 | xenbus_dev_fatal(dev, err, "reading %s/%s", |
1014 | dir, ring_ref_name); | |
86839c56 BL |
1015 | return err; |
1016 | } | |
4a8c31a1 DZ |
1017 | } |
1018 | ||
ae78ca3c | 1019 | err = -ENOMEM; |
86839c56 | 1020 | for (i = 0; i < nr_grefs * XEN_BLKIF_REQS_PER_PAGE; i++) { |
69b91ede BL |
1021 | req = kzalloc(sizeof(*req), GFP_KERNEL); |
1022 | if (!req) | |
1023 | goto fail; | |
59795700 | 1024 | list_add_tail(&req->free_list, &ring->pending_free); |
69b91ede BL |
1025 | for (j = 0; j < MAX_INDIRECT_SEGMENTS; j++) { |
1026 | req->segments[j] = kzalloc(sizeof(*req->segments[0]), GFP_KERNEL); | |
1027 | if (!req->segments[j]) | |
1028 | goto fail; | |
1029 | } | |
1030 | for (j = 0; j < MAX_INDIRECT_PAGES; j++) { | |
1031 | req->indirect_pages[j] = kzalloc(sizeof(*req->indirect_pages[0]), | |
1032 | GFP_KERNEL); | |
1033 | if (!req->indirect_pages[j]) | |
1034 | goto fail; | |
1035 | } | |
1036 | } | |
1037 | ||
4d05a28d | 1038 | /* Map the shared frame, irq etc. */ |
59795700 | 1039 | err = xen_blkif_map(ring, ring_ref, nr_grefs, evtchn); |
4d05a28d | 1040 | if (err) { |
86839c56 | 1041 | xenbus_dev_fatal(dev, err, "mapping ring-ref port %u", evtchn); |
ae78ca3c | 1042 | goto fail; |
4d05a28d KRW |
1043 | } |
1044 | ||
1045 | return 0; | |
69b91ede BL |
1046 | |
1047 | fail: | |
59795700 | 1048 | list_for_each_entry_safe(req, n, &ring->pending_free, free_list) { |
69b91ede BL |
1049 | list_del(&req->free_list); |
1050 | for (j = 0; j < MAX_INDIRECT_SEGMENTS; j++) { | |
1051 | if (!req->segments[j]) | |
1052 | break; | |
1053 | kfree(req->segments[j]); | |
1054 | } | |
1055 | for (j = 0; j < MAX_INDIRECT_PAGES; j++) { | |
1056 | if (!req->indirect_pages[j]) | |
1057 | break; | |
1058 | kfree(req->indirect_pages[j]); | |
1059 | } | |
1060 | kfree(req); | |
1061 | } | |
ae78ca3c | 1062 | return err; |
2fb1ef4f KRW |
1063 | } |
1064 | ||
1065 | static int connect_ring(struct backend_info *be) | |
1066 | { | |
1067 | struct xenbus_device *dev = be->dev; | |
5b8e432d | 1068 | struct xen_blkif *blkif = be->blkif; |
2fb1ef4f KRW |
1069 | char protocol[64] = ""; |
1070 | int err, i; | |
1071 | char *xspath; | |
1072 | size_t xspathsize; | |
1073 | const size_t xenstore_path_ext_size = 11; /* sufficient for "/queue-NNN" */ | |
d62d8600 | 1074 | unsigned int requested_num_queues = 0; |
4a8c31a1 | 1075 | unsigned int ring_page_order; |
2fb1ef4f KRW |
1076 | |
1077 | pr_debug("%s %s\n", __func__, dev->otherend); | |
1078 | ||
5b8e432d | 1079 | blkif->blk_protocol = BLKIF_PROTOCOL_DEFAULT; |
6694389a JB |
1080 | err = xenbus_scanf(XBT_NIL, dev->otherend, "protocol", |
1081 | "%63s", protocol); | |
1082 | if (err <= 0) | |
2fb1ef4f KRW |
1083 | strcpy(protocol, "unspecified, assuming default"); |
1084 | else if (0 == strcmp(protocol, XEN_IO_PROTO_ABI_NATIVE)) | |
5b8e432d | 1085 | blkif->blk_protocol = BLKIF_PROTOCOL_NATIVE; |
2fb1ef4f | 1086 | else if (0 == strcmp(protocol, XEN_IO_PROTO_ABI_X86_32)) |
5b8e432d | 1087 | blkif->blk_protocol = BLKIF_PROTOCOL_X86_32; |
2fb1ef4f | 1088 | else if (0 == strcmp(protocol, XEN_IO_PROTO_ABI_X86_64)) |
5b8e432d | 1089 | blkif->blk_protocol = BLKIF_PROTOCOL_X86_64; |
2fb1ef4f KRW |
1090 | else { |
1091 | xenbus_dev_fatal(dev, err, "unknown fe protocol %s", protocol); | |
bde21f73 | 1092 | return -ENOSYS; |
2fb1ef4f | 1093 | } |
aac8a70d SP |
1094 | if (blkif->vbd.feature_gnt_persistent) |
1095 | blkif->vbd.feature_gnt_persistent = | |
1096 | xenbus_read_unsigned(dev->otherend, | |
1097 | "feature-persistent", 0); | |
1098 | ||
5b8e432d | 1099 | blkif->vbd.overflow_max_grants = 0; |
2fb1ef4f | 1100 | |
d62d8600 BL |
1101 | /* |
1102 | * Read the number of hardware queues from frontend. | |
1103 | */ | |
8235777b JG |
1104 | requested_num_queues = xenbus_read_unsigned(dev->otherend, |
1105 | "multi-queue-num-queues", | |
1106 | 1); | |
1107 | if (requested_num_queues > xenblk_max_queues | |
1108 | || requested_num_queues == 0) { | |
1109 | /* Buggy or malicious guest. */ | |
1110 | xenbus_dev_fatal(dev, err, | |
1111 | "guest requested %u queues, exceeding the maximum of %u.", | |
1112 | requested_num_queues, xenblk_max_queues); | |
1113 | return -ENOSYS; | |
d62d8600 | 1114 | } |
5b8e432d DZ |
1115 | blkif->nr_rings = requested_num_queues; |
1116 | if (xen_blkif_alloc_rings(blkif)) | |
d62d8600 BL |
1117 | return -ENOMEM; |
1118 | ||
2fb1ef4f | 1119 | pr_info("%s: using %d queues, protocol %d (%s) %s\n", dev->nodename, |
5b8e432d | 1120 | blkif->nr_rings, blkif->blk_protocol, protocol, |
aac8a70d | 1121 | blkif->vbd.feature_gnt_persistent ? "persistent grants" : ""); |
2fb1ef4f | 1122 | |
6211a3f4 PD |
1123 | err = xenbus_scanf(XBT_NIL, dev->otherend, "ring-page-order", "%u", |
1124 | &ring_page_order); | |
1125 | if (err != 1) { | |
1126 | blkif->nr_ring_pages = 1; | |
1127 | blkif->multi_ref = false; | |
1128 | } else if (ring_page_order <= xen_blkif_max_ring_order) { | |
1129 | blkif->nr_ring_pages = 1 << ring_page_order; | |
1130 | blkif->multi_ref = true; | |
1131 | } else { | |
4a8c31a1 DZ |
1132 | err = -EINVAL; |
1133 | xenbus_dev_fatal(dev, err, | |
1134 | "requested ring page order %d exceed max:%d", | |
1135 | ring_page_order, | |
1136 | xen_blkif_max_ring_order); | |
1137 | return err; | |
1138 | } | |
1139 | ||
5b8e432d DZ |
1140 | if (blkif->nr_rings == 1) |
1141 | return read_per_ring_refs(&blkif->rings[0], dev->otherend); | |
2fb1ef4f KRW |
1142 | else { |
1143 | xspathsize = strlen(dev->otherend) + xenstore_path_ext_size; | |
1144 | xspath = kmalloc(xspathsize, GFP_KERNEL); | |
1145 | if (!xspath) { | |
1146 | xenbus_dev_fatal(dev, -ENOMEM, "reading ring references"); | |
1147 | return -ENOMEM; | |
1148 | } | |
1149 | ||
5b8e432d | 1150 | for (i = 0; i < blkif->nr_rings; i++) { |
2fb1ef4f KRW |
1151 | memset(xspath, 0, xspathsize); |
1152 | snprintf(xspath, xspathsize, "%s/queue-%u", dev->otherend, i); | |
5b8e432d | 1153 | err = read_per_ring_refs(&blkif->rings[i], xspath); |
2fb1ef4f KRW |
1154 | if (err) { |
1155 | kfree(xspath); | |
1156 | return err; | |
1157 | } | |
1158 | } | |
1159 | kfree(xspath); | |
1160 | } | |
1161 | return 0; | |
4d05a28d KRW |
1162 | } |
1163 | ||
8b6bf747 | 1164 | static const struct xenbus_device_id xen_blkbk_ids[] = { |
4d05a28d KRW |
1165 | { "vbd" }, |
1166 | { "" } | |
1167 | }; | |
1168 | ||
95afae48 DV |
1169 | static struct xenbus_driver xen_blkbk_driver = { |
1170 | .ids = xen_blkbk_ids, | |
8b6bf747 KRW |
1171 | .probe = xen_blkbk_probe, |
1172 | .remove = xen_blkbk_remove, | |
f4eef1b6 PD |
1173 | .otherend_changed = frontend_changed, |
1174 | .allow_rebind = true, | |
cb9369bd | 1175 | .reclaim_memory = reclaim_memory, |
95afae48 | 1176 | }; |
4d05a28d | 1177 | |
8b6bf747 | 1178 | int xen_blkif_xenbus_init(void) |
4d05a28d | 1179 | { |
73db144b | 1180 | return xenbus_register_backend(&xen_blkbk_driver); |
4d05a28d | 1181 | } |
14855954 PD |
1182 | |
1183 | void xen_blkif_xenbus_fini(void) | |
1184 | { | |
1185 | xenbus_unregister_driver(&xen_blkbk_driver); | |
1186 | } |