Commit | Line | Data |
---|---|---|
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 <linux/module.h> |
12 | #include <linux/kthread.h> | |
cbcc268b | 13 | #include <linux/pagemap.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? */ | |
436d3705 | 84 | if (!blkif->rings || !blkif->rings[0].irq || !blkif->vbd.bdev_handle) |
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 | ||
436d3705 | 102 | err = sync_blockdev(blkif->vbd.bdev_handle->bdev); |
cbf46290 CL |
103 | if (err) { |
104 | xenbus_dev_error(blkif->be->dev, err, "block flush"); | |
105 | return; | |
106 | } | |
436d3705 JK |
107 | invalidate_inode_pages2( |
108 | blkif->vbd.bdev_handle->bdev->bd_inode->i_mapping); | |
cbf46290 | 109 | |
2fb1ef4f KRW |
110 | for (i = 0; i < blkif->nr_rings; i++) { |
111 | ring = &blkif->rings[i]; | |
112 | ring->xenblkd = kthread_run(xen_blkif_schedule, ring, "%s-%d", name, i); | |
113 | if (IS_ERR(ring->xenblkd)) { | |
114 | err = PTR_ERR(ring->xenblkd); | |
115 | ring->xenblkd = NULL; | |
116 | xenbus_dev_fatal(blkif->be->dev, err, | |
117 | "start %s-%d xenblkd", name, i); | |
118 | goto out; | |
119 | } | |
120 | } | |
121 | return; | |
122 | ||
123 | out: | |
124 | while (--i >= 0) { | |
125 | ring = &blkif->rings[i]; | |
126 | kthread_stop(ring->xenblkd); | |
4d05a28d | 127 | } |
2fb1ef4f KRW |
128 | return; |
129 | } | |
130 | ||
131 | static int xen_blkif_alloc_rings(struct xen_blkif *blkif) | |
132 | { | |
133 | unsigned int r; | |
134 | ||
6396bb22 KC |
135 | blkif->rings = kcalloc(blkif->nr_rings, sizeof(struct xen_blkif_ring), |
136 | GFP_KERNEL); | |
2fb1ef4f KRW |
137 | if (!blkif->rings) |
138 | return -ENOMEM; | |
139 | ||
140 | for (r = 0; r < blkif->nr_rings; r++) { | |
141 | struct xen_blkif_ring *ring = &blkif->rings[r]; | |
142 | ||
143 | spin_lock_init(&ring->blk_ring_lock); | |
144 | init_waitqueue_head(&ring->wq); | |
145 | INIT_LIST_HEAD(&ring->pending_free); | |
d4bf0065 BL |
146 | INIT_LIST_HEAD(&ring->persistent_purge_list); |
147 | INIT_WORK(&ring->persistent_purge_work, xen_blkbk_unmap_purged_grants); | |
ca33479c | 148 | gnttab_page_cache_init(&ring->free_pages); |
2fb1ef4f KRW |
149 | |
150 | spin_lock_init(&ring->pending_free_lock); | |
151 | init_waitqueue_head(&ring->pending_free_wq); | |
152 | init_waitqueue_head(&ring->shutdown_wq); | |
153 | ring->blkif = blkif; | |
db6fbc10 | 154 | ring->st_print = jiffies; |
46464411 | 155 | ring->active = true; |
2fb1ef4f KRW |
156 | } |
157 | ||
158 | return 0; | |
4d05a28d KRW |
159 | } |
160 | ||
fc9be616 SP |
161 | /* Enable the persistent grants feature. */ |
162 | static bool feature_persistent = true; | |
163 | module_param(feature_persistent, bool, 0644); | |
164 | MODULE_PARM_DESC(feature_persistent, "Enables the persistent grants feature"); | |
165 | ||
30fd1502 | 166 | static struct xen_blkif *xen_blkif_alloc(domid_t domid) |
ee9ff853 | 167 | { |
30fd1502 | 168 | struct xen_blkif *blkif; |
ee9ff853 | 169 | |
402b27f9 | 170 | BUILD_BUG_ON(MAX_INDIRECT_PAGES > BLKIF_MAX_INDIRECT_PAGES_PER_REQUEST); |
ee9ff853 | 171 | |
654dbef2 | 172 | blkif = kmem_cache_zalloc(xen_blkif_cachep, GFP_KERNEL); |
ee9ff853 KRW |
173 | if (!blkif) |
174 | return ERR_PTR(-ENOMEM); | |
175 | ||
ee9ff853 | 176 | blkif->domid = domid; |
ee9ff853 | 177 | atomic_set(&blkif->refcnt, 1); |
29bde093 | 178 | init_completion(&blkif->drain_complete); |
fa2ac657 PD |
179 | |
180 | /* | |
181 | * Because freeing back to the cache may be deferred, it is not | |
182 | * safe to unload the module (and hence destroy the cache) until | |
183 | * this has completed. To prevent premature unloading, take an | |
184 | * extra module reference here and release only when the object | |
185 | * has been freed back to the cache. | |
186 | */ | |
187 | __module_get(THIS_MODULE); | |
59795700 | 188 | INIT_WORK(&blkif->free_work, xen_blkif_deferred_free); |
ee9ff853 KRW |
189 | |
190 | return blkif; | |
191 | } | |
192 | ||
59795700 | 193 | static int xen_blkif_map(struct xen_blkif_ring *ring, grant_ref_t *gref, |
86839c56 | 194 | unsigned int nr_grefs, unsigned int evtchn) |
ee9ff853 KRW |
195 | { |
196 | int err; | |
59795700 | 197 | struct xen_blkif *blkif = ring->blkif; |
f4eef1b6 PD |
198 | const struct blkif_common_sring *sring_common; |
199 | RING_IDX rsp_prod, req_prod; | |
200 | unsigned int size; | |
ee9ff853 KRW |
201 | |
202 | /* Already connected through? */ | |
59795700 | 203 | if (ring->irq) |
ee9ff853 KRW |
204 | return 0; |
205 | ||
86839c56 | 206 | err = xenbus_map_ring_valloc(blkif->be->dev, gref, nr_grefs, |
59795700 | 207 | &ring->blk_ring); |
2d073846 | 208 | if (err < 0) |
ee9ff853 | 209 | return err; |
ee9ff853 | 210 | |
f4eef1b6 PD |
211 | sring_common = (struct blkif_common_sring *)ring->blk_ring; |
212 | rsp_prod = READ_ONCE(sring_common->rsp_prod); | |
213 | req_prod = READ_ONCE(sring_common->req_prod); | |
214 | ||
ee9ff853 KRW |
215 | switch (blkif->blk_protocol) { |
216 | case BLKIF_PROTOCOL_NATIVE: | |
217 | { | |
f4eef1b6 PD |
218 | struct blkif_sring *sring_native = |
219 | (struct blkif_sring *)ring->blk_ring; | |
220 | ||
221 | BACK_RING_ATTACH(&ring->blk_rings.native, sring_native, | |
222 | rsp_prod, XEN_PAGE_SIZE * nr_grefs); | |
223 | size = __RING_SIZE(sring_native, XEN_PAGE_SIZE * nr_grefs); | |
ee9ff853 KRW |
224 | break; |
225 | } | |
226 | case BLKIF_PROTOCOL_X86_32: | |
227 | { | |
f4eef1b6 PD |
228 | struct blkif_x86_32_sring *sring_x86_32 = |
229 | (struct blkif_x86_32_sring *)ring->blk_ring; | |
230 | ||
231 | BACK_RING_ATTACH(&ring->blk_rings.x86_32, sring_x86_32, | |
232 | rsp_prod, XEN_PAGE_SIZE * nr_grefs); | |
233 | size = __RING_SIZE(sring_x86_32, XEN_PAGE_SIZE * nr_grefs); | |
ee9ff853 KRW |
234 | break; |
235 | } | |
236 | case BLKIF_PROTOCOL_X86_64: | |
237 | { | |
f4eef1b6 PD |
238 | struct blkif_x86_64_sring *sring_x86_64 = |
239 | (struct blkif_x86_64_sring *)ring->blk_ring; | |
240 | ||
241 | BACK_RING_ATTACH(&ring->blk_rings.x86_64, sring_x86_64, | |
242 | rsp_prod, XEN_PAGE_SIZE * nr_grefs); | |
243 | size = __RING_SIZE(sring_x86_64, XEN_PAGE_SIZE * nr_grefs); | |
ee9ff853 KRW |
244 | break; |
245 | } | |
246 | default: | |
247 | BUG(); | |
248 | } | |
249 | ||
f4eef1b6 PD |
250 | err = -EIO; |
251 | if (req_prod - rsp_prod > size) | |
252 | goto fail; | |
253 | ||
f2fa0e5e | 254 | err = bind_interdomain_evtchn_to_irqhandler_lateeoi(blkif->be->dev, |
01263a1f | 255 | evtchn, xen_blkif_be_int, 0, "blkif-backend", ring); |
f4eef1b6 PD |
256 | if (err < 0) |
257 | goto fail; | |
59795700 | 258 | ring->irq = err; |
ee9ff853 KRW |
259 | |
260 | return 0; | |
f4eef1b6 PD |
261 | |
262 | fail: | |
263 | xenbus_unmap_ring_vfree(blkif->be->dev, ring->blk_ring); | |
264 | ring->blk_rings.common.sring = NULL; | |
265 | return err; | |
ee9ff853 KRW |
266 | } |
267 | ||
814d04e7 | 268 | static int xen_blkif_disconnect(struct xen_blkif *blkif) |
ee9ff853 | 269 | { |
f929d42c | 270 | struct pending_req *req, *n; |
2fb1ef4f | 271 | unsigned int j, r; |
dc52d783 | 272 | bool busy = false; |
f929d42c | 273 | |
2fb1ef4f KRW |
274 | for (r = 0; r < blkif->nr_rings; r++) { |
275 | struct xen_blkif_ring *ring = &blkif->rings[r]; | |
276 | unsigned int i = 0; | |
ee9ff853 | 277 | |
46464411 JG |
278 | if (!ring->active) |
279 | continue; | |
280 | ||
2fb1ef4f KRW |
281 | if (ring->xenblkd) { |
282 | kthread_stop(ring->xenblkd); | |
1c728719 | 283 | ring->xenblkd = NULL; |
2fb1ef4f | 284 | wake_up(&ring->shutdown_wq); |
2fb1ef4f | 285 | } |
ee9ff853 | 286 | |
2fb1ef4f KRW |
287 | /* The above kthread_stop() guarantees that at this point we |
288 | * don't have any discard_io or other_io requests. So, checking | |
289 | * for inflight IO is enough. | |
290 | */ | |
dc52d783 AL |
291 | if (atomic_read(&ring->inflight) > 0) { |
292 | busy = true; | |
293 | continue; | |
294 | } | |
ee9ff853 | 295 | |
2fb1ef4f KRW |
296 | if (ring->irq) { |
297 | unbind_from_irqhandler(ring->irq, ring); | |
298 | ring->irq = 0; | |
299 | } | |
814d04e7 | 300 | |
2fb1ef4f KRW |
301 | if (ring->blk_rings.common.sring) { |
302 | xenbus_unmap_ring_vfree(blkif->be->dev, ring->blk_ring); | |
303 | ring->blk_rings.common.sring = NULL; | |
304 | } | |
12ea7296 | 305 | |
2fb1ef4f KRW |
306 | /* Remove all persistent grants and the cache of ballooned pages. */ |
307 | xen_blkbk_free_caches(ring); | |
f929d42c | 308 | |
2fb1ef4f KRW |
309 | /* Check that there is no request in use */ |
310 | list_for_each_entry_safe(req, n, &ring->pending_free, free_list) { | |
311 | list_del(&req->free_list); | |
f929d42c | 312 | |
2fb1ef4f KRW |
313 | for (j = 0; j < MAX_INDIRECT_SEGMENTS; j++) |
314 | kfree(req->segments[j]); | |
f929d42c | 315 | |
2fb1ef4f KRW |
316 | for (j = 0; j < MAX_INDIRECT_PAGES; j++) |
317 | kfree(req->indirect_pages[j]); | |
f929d42c | 318 | |
2fb1ef4f KRW |
319 | kfree(req); |
320 | i++; | |
321 | } | |
322 | ||
d4bf0065 BL |
323 | BUG_ON(atomic_read(&ring->persistent_gnt_in_use) != 0); |
324 | BUG_ON(!list_empty(&ring->persistent_purge_list)); | |
325 | BUG_ON(!RB_EMPTY_ROOT(&ring->persistent_gnts)); | |
ca33479c | 326 | BUG_ON(ring->free_pages.num_pages != 0); |
d4bf0065 | 327 | BUG_ON(ring->persistent_gnt_c != 0); |
2fb1ef4f | 328 | WARN_ON(i != (XEN_BLKIF_REQS_PER_PAGE * blkif->nr_ring_pages)); |
46464411 | 329 | ring->active = false; |
2fb1ef4f | 330 | } |
dc52d783 AL |
331 | if (busy) |
332 | return -EBUSY; | |
333 | ||
f929d42c | 334 | blkif->nr_ring_pages = 0; |
93bb277f BL |
335 | /* |
336 | * blkif->rings was allocated in connect_ring, so we should free it in | |
337 | * here. | |
338 | */ | |
339 | kfree(blkif->rings); | |
340 | blkif->rings = NULL; | |
341 | blkif->nr_rings = 0; | |
f929d42c | 342 | |
814d04e7 | 343 | return 0; |
ee9ff853 KRW |
344 | } |
345 | ||
2911758f | 346 | static void xen_blkif_free(struct xen_blkif *blkif) |
ee9ff853 | 347 | { |
71df1d7c | 348 | WARN_ON(xen_blkif_disconnect(blkif)); |
814d04e7 | 349 | xen_vbd_free(&blkif->vbd); |
71df1d7c JG |
350 | kfree(blkif->be->mode); |
351 | kfree(blkif->be); | |
bf0720c4 | 352 | |
ef753411 | 353 | /* Make sure everything is drained before shutting down */ |
8b6bf747 | 354 | kmem_cache_free(xen_blkif_cachep, blkif); |
fa2ac657 | 355 | module_put(THIS_MODULE); |
ee9ff853 KRW |
356 | } |
357 | ||
8b6bf747 | 358 | int __init xen_blkif_interface_init(void) |
ee9ff853 | 359 | { |
8b6bf747 | 360 | xen_blkif_cachep = kmem_cache_create("blkif_cache", |
30fd1502 | 361 | sizeof(struct xen_blkif), |
8b6bf747 KRW |
362 | 0, 0, NULL); |
363 | if (!xen_blkif_cachep) | |
ee9ff853 KRW |
364 | return -ENOMEM; |
365 | ||
366 | return 0; | |
367 | } | |
4d05a28d | 368 | |
14855954 PD |
369 | void xen_blkif_interface_fini(void) |
370 | { | |
371 | kmem_cache_destroy(xen_blkif_cachep); | |
372 | xen_blkif_cachep = NULL; | |
373 | } | |
374 | ||
a1397fa3 | 375 | /* |
4d05a28d KRW |
376 | * sysfs interface for VBD I/O requests |
377 | */ | |
378 | ||
db6fbc10 | 379 | #define VBD_SHOW_ALLRING(name, format) \ |
4d05a28d KRW |
380 | static ssize_t show_##name(struct device *_dev, \ |
381 | struct device_attribute *attr, \ | |
382 | char *buf) \ | |
383 | { \ | |
384 | struct xenbus_device *dev = to_xenbus_device(_dev); \ | |
5cf6e4f6 | 385 | struct backend_info *be = dev_get_drvdata(&dev->dev); \ |
db6fbc10 BL |
386 | struct xen_blkif *blkif = be->blkif; \ |
387 | unsigned int i; \ | |
388 | unsigned long long result = 0; \ | |
4d05a28d | 389 | \ |
db6fbc10 BL |
390 | if (!blkif->rings) \ |
391 | goto out; \ | |
392 | \ | |
393 | for (i = 0; i < blkif->nr_rings; i++) { \ | |
394 | struct xen_blkif_ring *ring = &blkif->rings[i]; \ | |
395 | \ | |
396 | result += ring->st_##name; \ | |
397 | } \ | |
398 | \ | |
399 | out: \ | |
400 | return sprintf(buf, format, result); \ | |
4d05a28d | 401 | } \ |
5657a819 | 402 | static DEVICE_ATTR(name, 0444, show_##name, NULL) |
4d05a28d | 403 | |
db6fbc10 BL |
404 | VBD_SHOW_ALLRING(oo_req, "%llu\n"); |
405 | VBD_SHOW_ALLRING(rd_req, "%llu\n"); | |
406 | VBD_SHOW_ALLRING(wr_req, "%llu\n"); | |
407 | VBD_SHOW_ALLRING(f_req, "%llu\n"); | |
408 | VBD_SHOW_ALLRING(ds_req, "%llu\n"); | |
409 | VBD_SHOW_ALLRING(rd_sect, "%llu\n"); | |
410 | VBD_SHOW_ALLRING(wr_sect, "%llu\n"); | |
4d05a28d | 411 | |
3d814731 | 412 | static struct attribute *xen_vbdstat_attrs[] = { |
4d05a28d KRW |
413 | &dev_attr_oo_req.attr, |
414 | &dev_attr_rd_req.attr, | |
415 | &dev_attr_wr_req.attr, | |
24f567f9 | 416 | &dev_attr_f_req.attr, |
b3cb0d6a | 417 | &dev_attr_ds_req.attr, |
4d05a28d KRW |
418 | &dev_attr_rd_sect.attr, |
419 | &dev_attr_wr_sect.attr, | |
420 | NULL | |
421 | }; | |
422 | ||
53043948 | 423 | static const struct attribute_group xen_vbdstat_group = { |
4d05a28d | 424 | .name = "statistics", |
3d814731 | 425 | .attrs = xen_vbdstat_attrs, |
4d05a28d KRW |
426 | }; |
427 | ||
db6fbc10 BL |
428 | #define VBD_SHOW(name, format, args...) \ |
429 | static ssize_t show_##name(struct device *_dev, \ | |
430 | struct device_attribute *attr, \ | |
431 | char *buf) \ | |
432 | { \ | |
433 | struct xenbus_device *dev = to_xenbus_device(_dev); \ | |
434 | struct backend_info *be = dev_get_drvdata(&dev->dev); \ | |
435 | \ | |
436 | return sprintf(buf, format, ##args); \ | |
437 | } \ | |
5657a819 | 438 | static DEVICE_ATTR(name, 0444, show_##name, NULL) |
db6fbc10 | 439 | |
4d05a28d KRW |
440 | VBD_SHOW(physical_device, "%x:%x\n", be->major, be->minor); |
441 | VBD_SHOW(mode, "%s\n", be->mode); | |
442 | ||
2911758f | 443 | static int xenvbd_sysfs_addif(struct xenbus_device *dev) |
4d05a28d KRW |
444 | { |
445 | int error; | |
446 | ||
447 | error = device_create_file(&dev->dev, &dev_attr_physical_device); | |
d6091b21 | 448 | if (error) |
4d05a28d KRW |
449 | goto fail1; |
450 | ||
451 | error = device_create_file(&dev->dev, &dev_attr_mode); | |
452 | if (error) | |
453 | goto fail2; | |
454 | ||
3d814731 | 455 | error = sysfs_create_group(&dev->dev.kobj, &xen_vbdstat_group); |
4d05a28d KRW |
456 | if (error) |
457 | goto fail3; | |
458 | ||
459 | return 0; | |
460 | ||
3d814731 | 461 | fail3: sysfs_remove_group(&dev->dev.kobj, &xen_vbdstat_group); |
4d05a28d KRW |
462 | fail2: device_remove_file(&dev->dev, &dev_attr_mode); |
463 | fail1: device_remove_file(&dev->dev, &dev_attr_physical_device); | |
464 | return error; | |
465 | } | |
466 | ||
2911758f | 467 | static void xenvbd_sysfs_delif(struct xenbus_device *dev) |
4d05a28d | 468 | { |
3d814731 | 469 | sysfs_remove_group(&dev->dev.kobj, &xen_vbdstat_group); |
4d05a28d KRW |
470 | device_remove_file(&dev->dev, &dev_attr_mode); |
471 | device_remove_file(&dev->dev, &dev_attr_physical_device); | |
472 | } | |
473 | ||
3d814731 | 474 | static void xen_vbd_free(struct xen_vbd *vbd) |
42c7841d | 475 | { |
436d3705 JK |
476 | if (vbd->bdev_handle) |
477 | bdev_release(vbd->bdev_handle); | |
478 | vbd->bdev_handle = NULL; | |
42c7841d KRW |
479 | } |
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; |
436d3705 | 486 | struct bdev_handle *bdev_handle; |
42c7841d KRW |
487 | |
488 | vbd = &blkif->vbd; | |
489 | vbd->handle = handle; | |
490 | vbd->readonly = readonly; | |
491 | vbd->type = 0; | |
492 | ||
493 | vbd->pdevice = MKDEV(major, minor); | |
494 | ||
436d3705 | 495 | bdev_handle = bdev_open_by_dev(vbd->pdevice, vbd->readonly ? |
05bdb996 | 496 | BLK_OPEN_READ : BLK_OPEN_WRITE, NULL, NULL); |
42c7841d | 497 | |
436d3705 | 498 | if (IS_ERR(bdev_handle)) { |
77387b82 | 499 | pr_warn("xen_vbd_create: device %08x could not be opened\n", |
42c7841d KRW |
500 | vbd->pdevice); |
501 | return -ENOENT; | |
502 | } | |
503 | ||
436d3705 JK |
504 | vbd->bdev_handle = bdev_handle; |
505 | if (vbd->bdev_handle->bdev->bd_disk == NULL) { | |
77387b82 | 506 | pr_warn("xen_vbd_create: device %08x doesn't exist\n", |
42c7841d | 507 | vbd->pdevice); |
3d814731 | 508 | xen_vbd_free(vbd); |
42c7841d KRW |
509 | return -ENOENT; |
510 | } | |
6464920a | 511 | vbd->size = vbd_sz(vbd); |
42c7841d | 512 | |
436d3705 | 513 | if (cdrom || disk_to_cdi(vbd->bdev_handle->bdev->bd_disk)) |
42c7841d | 514 | vbd->type |= VDISK_CDROM; |
436d3705 | 515 | if (vbd->bdev_handle->bdev->bd_disk->flags & GENHD_FL_REMOVABLE) |
42c7841d KRW |
516 | vbd->type |= VDISK_REMOVABLE; |
517 | ||
436d3705 | 518 | if (bdev_write_cache(bdev_handle->bdev)) |
24f567f9 | 519 | vbd->flush_support = true; |
436d3705 | 520 | if (bdev_max_secure_erase_sectors(bdev_handle->bdev)) |
5ea42986 KRW |
521 | vbd->discard_secure = true; |
522 | ||
77387b82 | 523 | pr_debug("Successful creation of handle=%04x (dom=%u)\n", |
42c7841d KRW |
524 | handle, blkif->domid); |
525 | return 0; | |
526 | } | |
8557bbe5 | 527 | |
7cffcade | 528 | static void xen_blkbk_remove(struct xenbus_device *dev) |
4d05a28d | 529 | { |
5cf6e4f6 | 530 | struct backend_info *be = dev_get_drvdata(&dev->dev); |
4d05a28d | 531 | |
77387b82 | 532 | pr_debug("%s %p %d\n", __func__, dev, dev->otherend_id); |
4d05a28d KRW |
533 | |
534 | if (be->major || be->minor) | |
535 | xenvbd_sysfs_delif(dev); | |
536 | ||
537 | if (be->backend_watch.node) { | |
538 | unregister_xenbus_watch(&be->backend_watch); | |
539 | kfree(be->backend_watch.node); | |
540 | be->backend_watch.node = NULL; | |
541 | } | |
542 | ||
814d04e7 VP |
543 | dev_set_drvdata(&dev->dev, NULL); |
544 | ||
2d4456c7 | 545 | if (be->blkif) { |
8b6bf747 | 546 | xen_blkif_disconnect(be->blkif); |
4d05a28d | 547 | |
2d4456c7 GS |
548 | /* Put the reference we set in xen_blkif_alloc(). */ |
549 | xen_blkif_put(be->blkif); | |
550 | } | |
4d05a28d KRW |
551 | } |
552 | ||
24f567f9 KRW |
553 | int xen_blkbk_flush_diskcache(struct xenbus_transaction xbt, |
554 | struct backend_info *be, int state) | |
4d05a28d KRW |
555 | { |
556 | struct xenbus_device *dev = be->dev; | |
557 | int err; | |
558 | ||
24f567f9 | 559 | err = xenbus_printf(xbt, dev->nodename, "feature-flush-cache", |
4d05a28d KRW |
560 | "%d", state); |
561 | if (err) | |
3389bb8b | 562 | dev_warn(&dev->dev, "writing feature-flush-cache (%d)", err); |
4d05a28d KRW |
563 | |
564 | return err; | |
565 | } | |
566 | ||
3389bb8b | 567 | static void xen_blkbk_discard(struct xenbus_transaction xbt, struct backend_info *be) |
b3cb0d6a LD |
568 | { |
569 | struct xenbus_device *dev = be->dev; | |
570 | struct xen_blkif *blkif = be->blkif; | |
b3cb0d6a | 571 | int err; |
8235777b | 572 | int state = 0; |
436d3705 | 573 | struct block_device *bdev = be->blkif->vbd.bdev_handle->bdev; |
4dae7670 | 574 | |
8235777b | 575 | if (!xenbus_read_unsigned(dev->nodename, "discard-enable", 1)) |
c926b701 OH |
576 | return; |
577 | ||
70200574 | 578 | if (bdev_max_discard_sectors(bdev)) { |
4dae7670 KRW |
579 | err = xenbus_printf(xbt, dev->nodename, |
580 | "discard-granularity", "%u", | |
0000f2f7 | 581 | bdev_discard_granularity(bdev)); |
4dae7670 | 582 | if (err) { |
3389bb8b KRW |
583 | dev_warn(&dev->dev, "writing discard-granularity (%d)", err); |
584 | return; | |
4dae7670 KRW |
585 | } |
586 | err = xenbus_printf(xbt, dev->nodename, | |
587 | "discard-alignment", "%u", | |
0000f2f7 | 588 | bdev_discard_alignment(bdev)); |
4dae7670 | 589 | if (err) { |
3389bb8b KRW |
590 | dev_warn(&dev->dev, "writing discard-alignment (%d)", err); |
591 | return; | |
b3cb0d6a | 592 | } |
4dae7670 KRW |
593 | state = 1; |
594 | /* Optional. */ | |
595 | err = xenbus_printf(xbt, dev->nodename, | |
596 | "discard-secure", "%d", | |
597 | blkif->vbd.discard_secure); | |
598 | if (err) { | |
a71e23d9 | 599 | dev_warn(&dev->dev, "writing discard-secure (%d)", err); |
3389bb8b | 600 | return; |
b3cb0d6a | 601 | } |
b3cb0d6a | 602 | } |
b3cb0d6a LD |
603 | err = xenbus_printf(xbt, dev->nodename, "feature-discard", |
604 | "%d", state); | |
605 | if (err) | |
3389bb8b | 606 | dev_warn(&dev->dev, "writing feature-discard (%d)", err); |
b3cb0d6a | 607 | } |
8557bbe5 | 608 | |
29bde093 KRW |
609 | int xen_blkbk_barrier(struct xenbus_transaction xbt, |
610 | struct backend_info *be, int state) | |
611 | { | |
612 | struct xenbus_device *dev = be->dev; | |
613 | int err; | |
614 | ||
615 | err = xenbus_printf(xbt, dev->nodename, "feature-barrier", | |
616 | "%d", state); | |
617 | if (err) | |
3389bb8b | 618 | dev_warn(&dev->dev, "writing feature-barrier (%d)", err); |
29bde093 KRW |
619 | |
620 | return err; | |
621 | } | |
b3cb0d6a | 622 | |
01f37f2d | 623 | /* |
4d05a28d KRW |
624 | * Entry point to this code when a new device is created. Allocate the basic |
625 | * structures, and watch the store waiting for the hotplug scripts to tell us | |
626 | * the device's physical major and minor numbers. Switch to InitWait. | |
627 | */ | |
8b6bf747 KRW |
628 | static int xen_blkbk_probe(struct xenbus_device *dev, |
629 | const struct xenbus_device_id *id) | |
4d05a28d KRW |
630 | { |
631 | int err; | |
632 | struct backend_info *be = kzalloc(sizeof(struct backend_info), | |
633 | GFP_KERNEL); | |
77387b82 TC |
634 | |
635 | /* match the pr_debug in xen_blkbk_remove */ | |
636 | pr_debug("%s %p %d\n", __func__, dev, dev->otherend_id); | |
637 | ||
4d05a28d KRW |
638 | if (!be) { |
639 | xenbus_dev_fatal(dev, -ENOMEM, | |
640 | "allocating backend structure"); | |
641 | return -ENOMEM; | |
642 | } | |
643 | be->dev = dev; | |
5cf6e4f6 | 644 | dev_set_drvdata(&dev->dev, be); |
4d05a28d | 645 | |
8b6bf747 | 646 | be->blkif = xen_blkif_alloc(dev->otherend_id); |
4d05a28d KRW |
647 | if (IS_ERR(be->blkif)) { |
648 | err = PTR_ERR(be->blkif); | |
649 | be->blkif = NULL; | |
650 | xenbus_dev_fatal(dev, err, "creating block interface"); | |
651 | goto fail; | |
652 | } | |
653 | ||
5a705845 JB |
654 | err = xenbus_printf(XBT_NIL, dev->nodename, |
655 | "feature-max-indirect-segments", "%u", | |
656 | MAX_INDIRECT_SEGMENTS); | |
657 | if (err) | |
658 | dev_warn(&dev->dev, | |
659 | "writing %s/feature-max-indirect-segments (%d)", | |
660 | dev->nodename, err); | |
661 | ||
d62d8600 BL |
662 | /* Multi-queue: advertise how many queues are supported by us.*/ |
663 | err = xenbus_printf(XBT_NIL, dev->nodename, | |
664 | "multi-queue-max-queues", "%u", xenblk_max_queues); | |
665 | if (err) | |
666 | pr_warn("Error writing multi-queue-max-queues\n"); | |
667 | ||
4d05a28d KRW |
668 | /* setup back pointer */ |
669 | be->blkif->be = be; | |
670 | ||
2e85d32b SP |
671 | err = xenbus_watch_pathfmt(dev, &be->backend_watch, NULL, |
672 | backend_changed, | |
88122933 | 673 | "%s/%s", dev->nodename, "physical-device"); |
4d05a28d KRW |
674 | if (err) |
675 | goto fail; | |
676 | ||
86839c56 BL |
677 | err = xenbus_printf(XBT_NIL, dev->nodename, "max-ring-page-order", "%u", |
678 | xen_blkif_max_ring_order); | |
679 | if (err) | |
680 | pr_warn("%s write out 'max-ring-page-order' failed\n", __func__); | |
681 | ||
4d05a28d KRW |
682 | err = xenbus_switch_state(dev, XenbusStateInitWait); |
683 | if (err) | |
684 | goto fail; | |
685 | ||
686 | return 0; | |
687 | ||
688 | fail: | |
77387b82 | 689 | pr_warn("%s failed\n", __func__); |
8b6bf747 | 690 | xen_blkbk_remove(dev); |
4d05a28d KRW |
691 | return err; |
692 | } | |
693 | ||
01f37f2d | 694 | /* |
4d05a28d KRW |
695 | * Callback received when the hotplug scripts have placed the physical-device |
696 | * node. Read it and the mode node, and create a vbd. If the frontend is | |
697 | * ready, connect. | |
698 | */ | |
699 | static void backend_changed(struct xenbus_watch *watch, | |
5584ea25 | 700 | const char *path, const char *token) |
4d05a28d KRW |
701 | { |
702 | int err; | |
703 | unsigned major; | |
704 | unsigned minor; | |
705 | struct backend_info *be | |
706 | = container_of(watch, struct backend_info, backend_watch); | |
707 | struct xenbus_device *dev = be->dev; | |
708 | int cdrom = 0; | |
9d092603 | 709 | unsigned long handle; |
4d05a28d KRW |
710 | char *device_type; |
711 | ||
77387b82 | 712 | pr_debug("%s %p %d\n", __func__, dev, dev->otherend_id); |
4d05a28d KRW |
713 | |
714 | err = xenbus_scanf(XBT_NIL, dev->nodename, "physical-device", "%x:%x", | |
715 | &major, &minor); | |
716 | if (XENBUS_EXIST_ERR(err)) { | |
01f37f2d KRW |
717 | /* |
718 | * Since this watch will fire once immediately after it is | |
719 | * registered, we expect this. Ignore it, and wait for the | |
720 | * hotplug scripts. | |
721 | */ | |
4d05a28d KRW |
722 | return; |
723 | } | |
724 | if (err != 2) { | |
725 | xenbus_dev_fatal(dev, err, "reading physical-device"); | |
726 | return; | |
727 | } | |
728 | ||
9d092603 JB |
729 | if (be->major | be->minor) { |
730 | if (be->major != major || be->minor != minor) | |
77387b82 | 731 | pr_warn("changing physical device (from %x:%x to %x:%x) not supported.\n", |
9d092603 | 732 | be->major, be->minor, major, minor); |
4d05a28d KRW |
733 | return; |
734 | } | |
735 | ||
736 | be->mode = xenbus_read(XBT_NIL, dev->nodename, "mode", NULL); | |
737 | if (IS_ERR(be->mode)) { | |
738 | err = PTR_ERR(be->mode); | |
739 | be->mode = NULL; | |
740 | xenbus_dev_fatal(dev, err, "reading mode"); | |
741 | return; | |
742 | } | |
743 | ||
744 | device_type = xenbus_read(XBT_NIL, dev->otherend, "device-type", NULL); | |
745 | if (!IS_ERR(device_type)) { | |
746 | cdrom = strcmp(device_type, "cdrom") == 0; | |
747 | kfree(device_type); | |
748 | } | |
749 | ||
9d092603 | 750 | /* Front end dir is a number, which is used as the handle. */ |
bb8e0e84 | 751 | err = kstrtoul(strrchr(dev->otherend, '/') + 1, 0, &handle); |
aea305e1 JB |
752 | if (err) { |
753 | kfree(be->mode); | |
754 | be->mode = NULL; | |
9d092603 | 755 | return; |
aea305e1 | 756 | } |
4d05a28d | 757 | |
9d092603 JB |
758 | be->major = major; |
759 | be->minor = minor; | |
4d05a28d | 760 | |
9d092603 JB |
761 | err = xen_vbd_create(be->blkif, handle, major, minor, |
762 | !strchr(be->mode, 'w'), cdrom); | |
4d05a28d | 763 | |
9d092603 JB |
764 | if (err) |
765 | xenbus_dev_fatal(dev, err, "creating vbd structure"); | |
766 | else { | |
4d05a28d KRW |
767 | err = xenvbd_sysfs_addif(dev); |
768 | if (err) { | |
3d814731 | 769 | xen_vbd_free(&be->blkif->vbd); |
4d05a28d | 770 | xenbus_dev_fatal(dev, err, "creating sysfs entries"); |
4d05a28d | 771 | } |
9d092603 | 772 | } |
4d05a28d | 773 | |
9d092603 JB |
774 | if (err) { |
775 | kfree(be->mode); | |
776 | be->mode = NULL; | |
777 | be->major = 0; | |
778 | be->minor = 0; | |
779 | } else { | |
4d05a28d | 780 | /* We're potentially connected now */ |
8b6bf747 | 781 | xen_update_blkif_status(be->blkif); |
4d05a28d KRW |
782 | } |
783 | } | |
784 | ||
01f37f2d | 785 | /* |
4d05a28d KRW |
786 | * Callback received when the frontend's state changes. |
787 | */ | |
788 | static void frontend_changed(struct xenbus_device *dev, | |
789 | enum xenbus_state frontend_state) | |
790 | { | |
5cf6e4f6 | 791 | struct backend_info *be = dev_get_drvdata(&dev->dev); |
4d05a28d KRW |
792 | int err; |
793 | ||
77387b82 | 794 | pr_debug("%s %p %s\n", __func__, dev, xenbus_strstate(frontend_state)); |
4d05a28d KRW |
795 | |
796 | switch (frontend_state) { | |
797 | case XenbusStateInitialising: | |
798 | if (dev->state == XenbusStateClosed) { | |
77387b82 | 799 | pr_info("%s: prepare for reconnect\n", dev->nodename); |
4d05a28d KRW |
800 | xenbus_switch_state(dev, XenbusStateInitWait); |
801 | } | |
802 | break; | |
803 | ||
804 | case XenbusStateInitialised: | |
805 | case XenbusStateConnected: | |
01f37f2d KRW |
806 | /* |
807 | * Ensure we connect even when two watches fire in | |
42b2aa86 | 808 | * close succession and we miss the intermediate value |
01f37f2d KRW |
809 | * of frontend_state. |
810 | */ | |
4d05a28d KRW |
811 | if (dev->state == XenbusStateConnected) |
812 | break; | |
813 | ||
01f37f2d KRW |
814 | /* |
815 | * Enforce precondition before potential leak point. | |
1bc05b0a | 816 | * xen_blkif_disconnect() is idempotent. |
313d7b00 | 817 | */ |
814d04e7 VP |
818 | err = xen_blkif_disconnect(be->blkif); |
819 | if (err) { | |
820 | xenbus_dev_fatal(dev, err, "pending I/O"); | |
821 | break; | |
822 | } | |
313d7b00 | 823 | |
4d05a28d | 824 | err = connect_ring(be); |
2d0382fa KRW |
825 | if (err) { |
826 | /* | |
827 | * Clean up so that memory resources can be used by | |
828 | * other devices. connect_ring reported already error. | |
829 | */ | |
830 | xen_blkif_disconnect(be->blkif); | |
4d05a28d | 831 | break; |
2d0382fa | 832 | } |
8b6bf747 | 833 | xen_update_blkif_status(be->blkif); |
4d05a28d KRW |
834 | break; |
835 | ||
836 | case XenbusStateClosing: | |
4d05a28d KRW |
837 | xenbus_switch_state(dev, XenbusStateClosing); |
838 | break; | |
839 | ||
840 | case XenbusStateClosed: | |
6f5986bc | 841 | xen_blkif_disconnect(be->blkif); |
4d05a28d KRW |
842 | xenbus_switch_state(dev, XenbusStateClosed); |
843 | if (xenbus_dev_is_online(dev)) | |
844 | break; | |
df561f66 | 845 | fallthrough; |
3f2c9405 | 846 | /* if not online */ |
4d05a28d | 847 | case XenbusStateUnknown: |
1bc05b0a | 848 | /* implies xen_blkif_disconnect() via xen_blkbk_remove() */ |
4d05a28d KRW |
849 | device_unregister(&dev->dev); |
850 | break; | |
851 | ||
852 | default: | |
853 | xenbus_dev_fatal(dev, -EINVAL, "saw state %d at frontend", | |
854 | frontend_state); | |
855 | break; | |
856 | } | |
857 | } | |
858 | ||
cb9369bd SP |
859 | /* Once a memory pressure is detected, squeeze free page pools for a while. */ |
860 | static unsigned int buffer_squeeze_duration_ms = 10; | |
861 | module_param_named(buffer_squeeze_duration_ms, | |
862 | buffer_squeeze_duration_ms, int, 0644); | |
863 | MODULE_PARM_DESC(buffer_squeeze_duration_ms, | |
864 | "Duration in ms to squeeze pages buffer when a memory pressure is detected"); | |
865 | ||
866 | /* | |
867 | * Callback received when the memory pressure is detected. | |
868 | */ | |
869 | static void reclaim_memory(struct xenbus_device *dev) | |
870 | { | |
871 | struct backend_info *be = dev_get_drvdata(&dev->dev); | |
872 | ||
873 | if (!be) | |
874 | return; | |
875 | be->blkif->buffer_squeeze_end = jiffies + | |
876 | msecs_to_jiffies(buffer_squeeze_duration_ms); | |
877 | } | |
878 | ||
4d05a28d KRW |
879 | /* ** Connection ** */ |
880 | ||
01f37f2d | 881 | /* |
4d05a28d KRW |
882 | * Write the physical details regarding the block device to the store, and |
883 | * switch to Connected state. | |
884 | */ | |
885 | static void connect(struct backend_info *be) | |
886 | { | |
887 | struct xenbus_transaction xbt; | |
888 | int err; | |
889 | struct xenbus_device *dev = be->dev; | |
890 | ||
77387b82 | 891 | pr_debug("%s %s\n", __func__, dev->otherend); |
4d05a28d KRW |
892 | |
893 | /* Supply the information about the device the frontend needs */ | |
894 | again: | |
895 | err = xenbus_transaction_start(&xbt); | |
896 | if (err) { | |
897 | xenbus_dev_fatal(dev, err, "starting transaction"); | |
898 | return; | |
899 | } | |
900 | ||
3389bb8b KRW |
901 | /* If we can't advertise it is OK. */ |
902 | xen_blkbk_flush_diskcache(xbt, be, be->blkif->vbd.flush_support); | |
4d05a28d | 903 | |
3389bb8b | 904 | xen_blkbk_discard(xbt, be); |
b3cb0d6a | 905 | |
3389bb8b | 906 | xen_blkbk_barrier(xbt, be, be->blkif->vbd.flush_support); |
29bde093 | 907 | |
aac8a70d | 908 | err = xenbus_printf(xbt, dev->nodename, "feature-persistent", "%u", |
06ba5d2e | 909 | be->blkif->vbd.feature_gnt_persistent_parm); |
0a8704a5 RPM |
910 | if (err) { |
911 | xenbus_dev_fatal(dev, err, "writing %s/feature-persistent", | |
912 | dev->nodename); | |
913 | goto abort; | |
914 | } | |
915 | ||
4d05a28d | 916 | err = xenbus_printf(xbt, dev->nodename, "sectors", "%llu", |
42c7841d | 917 | (unsigned long long)vbd_sz(&be->blkif->vbd)); |
4d05a28d KRW |
918 | if (err) { |
919 | xenbus_dev_fatal(dev, err, "writing %s/sectors", | |
920 | dev->nodename); | |
921 | goto abort; | |
922 | } | |
923 | ||
924 | /* FIXME: use a typename instead */ | |
925 | err = xenbus_printf(xbt, dev->nodename, "info", "%u", | |
42c7841d KRW |
926 | be->blkif->vbd.type | |
927 | (be->blkif->vbd.readonly ? VDISK_READONLY : 0)); | |
4d05a28d KRW |
928 | if (err) { |
929 | xenbus_dev_fatal(dev, err, "writing %s/info", | |
930 | dev->nodename); | |
931 | goto abort; | |
932 | } | |
933 | err = xenbus_printf(xbt, dev->nodename, "sector-size", "%lu", | |
436d3705 JK |
934 | (unsigned long)bdev_logical_block_size( |
935 | be->blkif->vbd.bdev_handle->bdev)); | |
4d05a28d KRW |
936 | if (err) { |
937 | xenbus_dev_fatal(dev, err, "writing %s/sector-size", | |
938 | dev->nodename); | |
939 | goto abort; | |
940 | } | |
7c4d7d71 | 941 | err = xenbus_printf(xbt, dev->nodename, "physical-sector-size", "%u", |
436d3705 JK |
942 | bdev_physical_block_size( |
943 | be->blkif->vbd.bdev_handle->bdev)); | |
7c4d7d71 SB |
944 | if (err) |
945 | xenbus_dev_error(dev, err, "writing %s/physical-sector-size", | |
946 | dev->nodename); | |
4d05a28d KRW |
947 | |
948 | err = xenbus_transaction_end(xbt, 0); | |
949 | if (err == -EAGAIN) | |
950 | goto again; | |
951 | if (err) | |
952 | xenbus_dev_fatal(dev, err, "ending transaction"); | |
953 | ||
954 | err = xenbus_switch_state(dev, XenbusStateConnected); | |
955 | if (err) | |
08b8bfc1 | 956 | xenbus_dev_fatal(dev, err, "%s: switching to Connected state", |
4d05a28d KRW |
957 | dev->nodename); |
958 | ||
959 | return; | |
960 | abort: | |
961 | xenbus_transaction_end(xbt, 1); | |
962 | } | |
963 | ||
2fb1ef4f KRW |
964 | /* |
965 | * Each ring may have multi pages, depends on "ring-page-order". | |
966 | */ | |
967 | static int read_per_ring_refs(struct xen_blkif_ring *ring, const char *dir) | |
4d05a28d | 968 | { |
9cce2914 | 969 | unsigned int ring_ref[XENBUS_MAX_RING_GRANTS]; |
69b91ede BL |
970 | struct pending_req *req, *n; |
971 | int err, i, j; | |
2fb1ef4f KRW |
972 | struct xen_blkif *blkif = ring->blkif; |
973 | struct xenbus_device *dev = blkif->be->dev; | |
4a8c31a1 | 974 | unsigned int nr_grefs, evtchn; |
4d05a28d | 975 | |
2fb1ef4f | 976 | err = xenbus_scanf(XBT_NIL, dir, "event-channel", "%u", |
86839c56 BL |
977 | &evtchn); |
978 | if (err != 1) { | |
979 | err = -EINVAL; | |
2fb1ef4f | 980 | xenbus_dev_fatal(dev, err, "reading %s/event-channel", dir); |
4d05a28d KRW |
981 | return err; |
982 | } | |
86839c56 | 983 | |
4a8c31a1 DZ |
984 | nr_grefs = blkif->nr_ring_pages; |
985 | ||
986 | if (unlikely(!nr_grefs)) { | |
987 | WARN_ON(true); | |
988 | return -EINVAL; | |
989 | } | |
990 | ||
991 | for (i = 0; i < nr_grefs; i++) { | |
992 | char ring_ref_name[RINGREF_NAME_LEN]; | |
993 | ||
d75e7f63 PD |
994 | if (blkif->multi_ref) |
995 | snprintf(ring_ref_name, RINGREF_NAME_LEN, "ring-ref%u", i); | |
996 | else { | |
997 | WARN_ON(i != 0); | |
998 | snprintf(ring_ref_name, RINGREF_NAME_LEN, "ring-ref"); | |
999 | } | |
1000 | ||
4a8c31a1 DZ |
1001 | err = xenbus_scanf(XBT_NIL, dir, ring_ref_name, |
1002 | "%u", &ring_ref[i]); | |
1003 | ||
86839c56 BL |
1004 | if (err != 1) { |
1005 | err = -EINVAL; | |
4a8c31a1 DZ |
1006 | xenbus_dev_fatal(dev, err, "reading %s/%s", |
1007 | dir, ring_ref_name); | |
86839c56 BL |
1008 | return err; |
1009 | } | |
4a8c31a1 DZ |
1010 | } |
1011 | ||
ae78ca3c | 1012 | err = -ENOMEM; |
86839c56 | 1013 | for (i = 0; i < nr_grefs * XEN_BLKIF_REQS_PER_PAGE; i++) { |
69b91ede BL |
1014 | req = kzalloc(sizeof(*req), GFP_KERNEL); |
1015 | if (!req) | |
1016 | goto fail; | |
59795700 | 1017 | list_add_tail(&req->free_list, &ring->pending_free); |
69b91ede BL |
1018 | for (j = 0; j < MAX_INDIRECT_SEGMENTS; j++) { |
1019 | req->segments[j] = kzalloc(sizeof(*req->segments[0]), GFP_KERNEL); | |
1020 | if (!req->segments[j]) | |
1021 | goto fail; | |
1022 | } | |
1023 | for (j = 0; j < MAX_INDIRECT_PAGES; j++) { | |
1024 | req->indirect_pages[j] = kzalloc(sizeof(*req->indirect_pages[0]), | |
1025 | GFP_KERNEL); | |
1026 | if (!req->indirect_pages[j]) | |
1027 | goto fail; | |
1028 | } | |
1029 | } | |
1030 | ||
4d05a28d | 1031 | /* Map the shared frame, irq etc. */ |
59795700 | 1032 | err = xen_blkif_map(ring, ring_ref, nr_grefs, evtchn); |
4d05a28d | 1033 | if (err) { |
86839c56 | 1034 | xenbus_dev_fatal(dev, err, "mapping ring-ref port %u", evtchn); |
ae78ca3c | 1035 | goto fail; |
4d05a28d KRW |
1036 | } |
1037 | ||
1038 | return 0; | |
69b91ede BL |
1039 | |
1040 | fail: | |
59795700 | 1041 | list_for_each_entry_safe(req, n, &ring->pending_free, free_list) { |
69b91ede BL |
1042 | list_del(&req->free_list); |
1043 | for (j = 0; j < MAX_INDIRECT_SEGMENTS; j++) { | |
1044 | if (!req->segments[j]) | |
1045 | break; | |
1046 | kfree(req->segments[j]); | |
1047 | } | |
1048 | for (j = 0; j < MAX_INDIRECT_PAGES; j++) { | |
1049 | if (!req->indirect_pages[j]) | |
1050 | break; | |
1051 | kfree(req->indirect_pages[j]); | |
1052 | } | |
1053 | kfree(req); | |
1054 | } | |
ae78ca3c | 1055 | return err; |
2fb1ef4f KRW |
1056 | } |
1057 | ||
1058 | static int connect_ring(struct backend_info *be) | |
1059 | { | |
1060 | struct xenbus_device *dev = be->dev; | |
5b8e432d | 1061 | struct xen_blkif *blkif = be->blkif; |
2fb1ef4f KRW |
1062 | char protocol[64] = ""; |
1063 | int err, i; | |
1064 | char *xspath; | |
1065 | size_t xspathsize; | |
1066 | const size_t xenstore_path_ext_size = 11; /* sufficient for "/queue-NNN" */ | |
d62d8600 | 1067 | unsigned int requested_num_queues = 0; |
4a8c31a1 | 1068 | unsigned int ring_page_order; |
2fb1ef4f KRW |
1069 | |
1070 | pr_debug("%s %s\n", __func__, dev->otherend); | |
1071 | ||
5b8e432d | 1072 | blkif->blk_protocol = BLKIF_PROTOCOL_DEFAULT; |
6694389a JB |
1073 | err = xenbus_scanf(XBT_NIL, dev->otherend, "protocol", |
1074 | "%63s", protocol); | |
1075 | if (err <= 0) | |
2fb1ef4f KRW |
1076 | strcpy(protocol, "unspecified, assuming default"); |
1077 | else if (0 == strcmp(protocol, XEN_IO_PROTO_ABI_NATIVE)) | |
5b8e432d | 1078 | blkif->blk_protocol = BLKIF_PROTOCOL_NATIVE; |
2fb1ef4f | 1079 | else if (0 == strcmp(protocol, XEN_IO_PROTO_ABI_X86_32)) |
5b8e432d | 1080 | blkif->blk_protocol = BLKIF_PROTOCOL_X86_32; |
2fb1ef4f | 1081 | else if (0 == strcmp(protocol, XEN_IO_PROTO_ABI_X86_64)) |
5b8e432d | 1082 | blkif->blk_protocol = BLKIF_PROTOCOL_X86_64; |
2fb1ef4f KRW |
1083 | else { |
1084 | xenbus_dev_fatal(dev, err, "unknown fe protocol %s", protocol); | |
bde21f73 | 1085 | return -ENOSYS; |
2fb1ef4f | 1086 | } |
e94c6101 | 1087 | |
06ba5d2e SP |
1088 | blkif->vbd.feature_gnt_persistent_parm = feature_persistent; |
1089 | blkif->vbd.feature_gnt_persistent = | |
1090 | blkif->vbd.feature_gnt_persistent_parm && | |
e94c6101 | 1091 | xenbus_read_unsigned(dev->otherend, "feature-persistent", 0); |
aac8a70d | 1092 | |
5b8e432d | 1093 | blkif->vbd.overflow_max_grants = 0; |
2fb1ef4f | 1094 | |
d62d8600 BL |
1095 | /* |
1096 | * Read the number of hardware queues from frontend. | |
1097 | */ | |
8235777b JG |
1098 | requested_num_queues = xenbus_read_unsigned(dev->otherend, |
1099 | "multi-queue-num-queues", | |
1100 | 1); | |
1101 | if (requested_num_queues > xenblk_max_queues | |
1102 | || requested_num_queues == 0) { | |
1103 | /* Buggy or malicious guest. */ | |
1104 | xenbus_dev_fatal(dev, err, | |
1105 | "guest requested %u queues, exceeding the maximum of %u.", | |
1106 | requested_num_queues, xenblk_max_queues); | |
1107 | return -ENOSYS; | |
d62d8600 | 1108 | } |
5b8e432d DZ |
1109 | blkif->nr_rings = requested_num_queues; |
1110 | if (xen_blkif_alloc_rings(blkif)) | |
d62d8600 BL |
1111 | return -ENOMEM; |
1112 | ||
2fb1ef4f | 1113 | pr_info("%s: using %d queues, protocol %d (%s) %s\n", dev->nodename, |
5b8e432d | 1114 | blkif->nr_rings, blkif->blk_protocol, protocol, |
aac8a70d | 1115 | blkif->vbd.feature_gnt_persistent ? "persistent grants" : ""); |
2fb1ef4f | 1116 | |
d75e7f63 PD |
1117 | err = xenbus_scanf(XBT_NIL, dev->otherend, "ring-page-order", "%u", |
1118 | &ring_page_order); | |
1119 | if (err != 1) { | |
1120 | blkif->nr_ring_pages = 1; | |
1121 | blkif->multi_ref = false; | |
1122 | } else if (ring_page_order <= xen_blkif_max_ring_order) { | |
1123 | blkif->nr_ring_pages = 1 << ring_page_order; | |
1124 | blkif->multi_ref = true; | |
1125 | } else { | |
4a8c31a1 DZ |
1126 | err = -EINVAL; |
1127 | xenbus_dev_fatal(dev, err, | |
1128 | "requested ring page order %d exceed max:%d", | |
1129 | ring_page_order, | |
1130 | xen_blkif_max_ring_order); | |
1131 | return err; | |
1132 | } | |
1133 | ||
5b8e432d DZ |
1134 | if (blkif->nr_rings == 1) |
1135 | return read_per_ring_refs(&blkif->rings[0], dev->otherend); | |
2fb1ef4f KRW |
1136 | else { |
1137 | xspathsize = strlen(dev->otherend) + xenstore_path_ext_size; | |
1138 | xspath = kmalloc(xspathsize, GFP_KERNEL); | |
1139 | if (!xspath) { | |
1140 | xenbus_dev_fatal(dev, -ENOMEM, "reading ring references"); | |
1141 | return -ENOMEM; | |
1142 | } | |
1143 | ||
5b8e432d | 1144 | for (i = 0; i < blkif->nr_rings; i++) { |
2fb1ef4f KRW |
1145 | memset(xspath, 0, xspathsize); |
1146 | snprintf(xspath, xspathsize, "%s/queue-%u", dev->otherend, i); | |
5b8e432d | 1147 | err = read_per_ring_refs(&blkif->rings[i], xspath); |
2fb1ef4f KRW |
1148 | if (err) { |
1149 | kfree(xspath); | |
1150 | return err; | |
1151 | } | |
1152 | } | |
1153 | kfree(xspath); | |
1154 | } | |
1155 | return 0; | |
4d05a28d KRW |
1156 | } |
1157 | ||
8b6bf747 | 1158 | static const struct xenbus_device_id xen_blkbk_ids[] = { |
4d05a28d KRW |
1159 | { "vbd" }, |
1160 | { "" } | |
1161 | }; | |
1162 | ||
95afae48 DV |
1163 | static struct xenbus_driver xen_blkbk_driver = { |
1164 | .ids = xen_blkbk_ids, | |
8b6bf747 KRW |
1165 | .probe = xen_blkbk_probe, |
1166 | .remove = xen_blkbk_remove, | |
f4eef1b6 PD |
1167 | .otherend_changed = frontend_changed, |
1168 | .allow_rebind = true, | |
cb9369bd | 1169 | .reclaim_memory = reclaim_memory, |
95afae48 | 1170 | }; |
4d05a28d | 1171 | |
8b6bf747 | 1172 | int xen_blkif_xenbus_init(void) |
4d05a28d | 1173 | { |
73db144b | 1174 | return xenbus_register_backend(&xen_blkbk_driver); |
4d05a28d | 1175 | } |
14855954 PD |
1176 | |
1177 | void xen_blkif_xenbus_fini(void) | |
1178 | { | |
1179 | xenbus_unregister_driver(&xen_blkbk_driver); | |
1180 | } |