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 15 */ 16 17 #include <stdarg.h> 18 #include <linux/module.h> 19 #include <linux/kthread.h> 20 #include <xen/events.h> 21 #include <xen/grant_table.h> 22 #include "common.h" 23 24 struct backend_info { 25 struct xenbus_device *dev; 26 struct xen_blkif *blkif; 27 struct xenbus_watch backend_watch; 28 unsigned major; 29 unsigned minor; 30 char *mode; 31 }; 32 33 static struct kmem_cache *xen_blkif_cachep; 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 39 struct xenbus_device *xen_blkbk_xenbus(struct backend_info *be) 40 { 41 return be->dev; 42 } 43 44 static int blkback_name(struct xen_blkif *blkif, char *buf) 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 53 devname = strstr(devpath, "/dev/"); 54 if (devname != NULL) 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 65 static void xen_update_blkif_status(struct xen_blkif *blkif) 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 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 96 blkif->xenblkd = kthread_run(xen_blkif_schedule, blkif, name); 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"); 101 } 102 } 103 104 static struct xen_blkif *xen_blkif_alloc(domid_t domid) 105 { 106 struct xen_blkif *blkif; 107 108 blkif = kmem_cache_alloc(xen_blkif_cachep, GFP_KERNEL); 109 if (!blkif) 110 return ERR_PTR(-ENOMEM); 111 112 memset(blkif, 0, sizeof(*blkif)); 113 blkif->domid = domid; 114 spin_lock_init(&blkif->blk_ring_lock); 115 atomic_set(&blkif->refcnt, 1); 116 init_waitqueue_head(&blkif->wq); 117 blkif->st_print = jiffies; 118 init_waitqueue_head(&blkif->waiting_to_free); 119 120 return blkif; 121 } 122 123 static int map_frontend_page(struct xen_blkif *blkif, unsigned long shared_page) 124 { 125 struct gnttab_map_grant_ref op; 126 127 gnttab_set_map_op(&op, (unsigned long)blkif->blk_ring_area->addr, 128 GNTMAP_host_map, shared_page, blkif->domid); 129 130 if (HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, &op, 1)) 131 BUG(); 132 133 if (op.status) { 134 DPRINTK("Grant table operation failure !\n"); 135 return op.status; 136 } 137 138 blkif->shmem_ref = shared_page; 139 blkif->shmem_handle = op.handle; 140 141 return 0; 142 } 143 144 static void unmap_frontend_page(struct xen_blkif *blkif) 145 { 146 struct gnttab_unmap_grant_ref op; 147 148 gnttab_set_unmap_op(&op, (unsigned long)blkif->blk_ring_area->addr, 149 GNTMAP_host_map, blkif->shmem_handle); 150 151 if (HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, &op, 1)) 152 BUG(); 153 } 154 155 static int xen_blkif_map(struct xen_blkif *blkif, unsigned long shared_page, 156 unsigned int evtchn) 157 { 158 int err; 159 160 /* Already connected through? */ 161 if (blkif->irq) 162 return 0; 163 164 blkif->blk_ring_area = alloc_vm_area(PAGE_SIZE); 165 if (!blkif->blk_ring_area) 166 return -ENOMEM; 167 168 err = map_frontend_page(blkif, shared_page); 169 if (err) { 170 free_vm_area(blkif->blk_ring_area); 171 return err; 172 } 173 174 switch (blkif->blk_protocol) { 175 case BLKIF_PROTOCOL_NATIVE: 176 { 177 struct blkif_sring *sring; 178 sring = (struct blkif_sring *)blkif->blk_ring_area->addr; 179 BACK_RING_INIT(&blkif->blk_rings.native, sring, PAGE_SIZE); 180 break; 181 } 182 case BLKIF_PROTOCOL_X86_32: 183 { 184 struct blkif_x86_32_sring *sring_x86_32; 185 sring_x86_32 = (struct blkif_x86_32_sring *)blkif->blk_ring_area->addr; 186 BACK_RING_INIT(&blkif->blk_rings.x86_32, sring_x86_32, PAGE_SIZE); 187 break; 188 } 189 case BLKIF_PROTOCOL_X86_64: 190 { 191 struct blkif_x86_64_sring *sring_x86_64; 192 sring_x86_64 = (struct blkif_x86_64_sring *)blkif->blk_ring_area->addr; 193 BACK_RING_INIT(&blkif->blk_rings.x86_64, sring_x86_64, PAGE_SIZE); 194 break; 195 } 196 default: 197 BUG(); 198 } 199 200 err = bind_interdomain_evtchn_to_irqhandler(blkif->domid, evtchn, 201 xen_blkif_be_int, 0, 202 "blkif-backend", blkif); 203 if (err < 0) { 204 unmap_frontend_page(blkif); 205 free_vm_area(blkif->blk_ring_area); 206 blkif->blk_rings.common.sring = NULL; 207 return err; 208 } 209 blkif->irq = err; 210 211 return 0; 212 } 213 214 static void xen_blkif_disconnect(struct xen_blkif *blkif) 215 { 216 if (blkif->xenblkd) { 217 kthread_stop(blkif->xenblkd); 218 blkif->xenblkd = NULL; 219 } 220 221 atomic_dec(&blkif->refcnt); 222 wait_event(blkif->waiting_to_free, atomic_read(&blkif->refcnt) == 0); 223 atomic_inc(&blkif->refcnt); 224 225 if (blkif->irq) { 226 unbind_from_irqhandler(blkif->irq, blkif); 227 blkif->irq = 0; 228 } 229 230 if (blkif->blk_rings.common.sring) { 231 unmap_frontend_page(blkif); 232 free_vm_area(blkif->blk_ring_area); 233 blkif->blk_rings.common.sring = NULL; 234 } 235 } 236 237 void xen_blkif_free(struct xen_blkif *blkif) 238 { 239 if (!atomic_dec_and_test(&blkif->refcnt)) 240 BUG(); 241 kmem_cache_free(xen_blkif_cachep, blkif); 242 } 243 244 int __init xen_blkif_interface_init(void) 245 { 246 xen_blkif_cachep = kmem_cache_create("blkif_cache", 247 sizeof(struct xen_blkif), 248 0, 0, NULL); 249 if (!xen_blkif_cachep) 250 return -ENOMEM; 251 252 return 0; 253 } 254 255 /* 256 * sysfs interface for VBD I/O requests 257 */ 258 259 #define VBD_SHOW(name, format, args...) \ 260 static ssize_t show_##name(struct device *_dev, \ 261 struct device_attribute *attr, \ 262 char *buf) \ 263 { \ 264 struct xenbus_device *dev = to_xenbus_device(_dev); \ 265 struct backend_info *be = dev_get_drvdata(&dev->dev); \ 266 \ 267 return sprintf(buf, format, ##args); \ 268 } \ 269 static DEVICE_ATTR(name, S_IRUGO, show_##name, NULL) 270 271 VBD_SHOW(oo_req, "%d\n", be->blkif->st_oo_req); 272 VBD_SHOW(rd_req, "%d\n", be->blkif->st_rd_req); 273 VBD_SHOW(wr_req, "%d\n", be->blkif->st_wr_req); 274 VBD_SHOW(f_req, "%d\n", be->blkif->st_f_req); 275 VBD_SHOW(rd_sect, "%d\n", be->blkif->st_rd_sect); 276 VBD_SHOW(wr_sect, "%d\n", be->blkif->st_wr_sect); 277 278 static struct attribute *xen_vbdstat_attrs[] = { 279 &dev_attr_oo_req.attr, 280 &dev_attr_rd_req.attr, 281 &dev_attr_wr_req.attr, 282 &dev_attr_f_req.attr, 283 &dev_attr_rd_sect.attr, 284 &dev_attr_wr_sect.attr, 285 NULL 286 }; 287 288 static struct attribute_group xen_vbdstat_group = { 289 .name = "statistics", 290 .attrs = xen_vbdstat_attrs, 291 }; 292 293 VBD_SHOW(physical_device, "%x:%x\n", be->major, be->minor); 294 VBD_SHOW(mode, "%s\n", be->mode); 295 296 int xenvbd_sysfs_addif(struct xenbus_device *dev) 297 { 298 int error; 299 300 error = device_create_file(&dev->dev, &dev_attr_physical_device); 301 if (error) 302 goto fail1; 303 304 error = device_create_file(&dev->dev, &dev_attr_mode); 305 if (error) 306 goto fail2; 307 308 error = sysfs_create_group(&dev->dev.kobj, &xen_vbdstat_group); 309 if (error) 310 goto fail3; 311 312 return 0; 313 314 fail3: sysfs_remove_group(&dev->dev.kobj, &xen_vbdstat_group); 315 fail2: device_remove_file(&dev->dev, &dev_attr_mode); 316 fail1: device_remove_file(&dev->dev, &dev_attr_physical_device); 317 return error; 318 } 319 320 void xenvbd_sysfs_delif(struct xenbus_device *dev) 321 { 322 sysfs_remove_group(&dev->dev.kobj, &xen_vbdstat_group); 323 device_remove_file(&dev->dev, &dev_attr_mode); 324 device_remove_file(&dev->dev, &dev_attr_physical_device); 325 } 326 327 328 static void xen_vbd_free(struct xen_vbd *vbd) 329 { 330 if (vbd->bdev) 331 blkdev_put(vbd->bdev, vbd->readonly ? FMODE_READ : FMODE_WRITE); 332 vbd->bdev = NULL; 333 } 334 335 static int xen_vbd_create(struct xen_blkif *blkif, blkif_vdev_t handle, 336 unsigned major, unsigned minor, int readonly, 337 int cdrom) 338 { 339 struct xen_vbd *vbd; 340 struct block_device *bdev; 341 struct request_queue *q; 342 343 vbd = &blkif->vbd; 344 vbd->handle = handle; 345 vbd->readonly = readonly; 346 vbd->type = 0; 347 348 vbd->pdevice = MKDEV(major, minor); 349 350 bdev = blkdev_get_by_dev(vbd->pdevice, vbd->readonly ? 351 FMODE_READ : FMODE_WRITE, NULL); 352 353 if (IS_ERR(bdev)) { 354 DPRINTK("xen_vbd_create: device %08x could not be opened.\n", 355 vbd->pdevice); 356 return -ENOENT; 357 } 358 359 vbd->bdev = bdev; 360 if (vbd->bdev->bd_disk == NULL) { 361 DPRINTK("xen_vbd_create: device %08x doesn't exist.\n", 362 vbd->pdevice); 363 xen_vbd_free(vbd); 364 return -ENOENT; 365 } 366 vbd->size = vbd_sz(vbd); 367 368 if (vbd->bdev->bd_disk->flags & GENHD_FL_CD || cdrom) 369 vbd->type |= VDISK_CDROM; 370 if (vbd->bdev->bd_disk->flags & GENHD_FL_REMOVABLE) 371 vbd->type |= VDISK_REMOVABLE; 372 373 q = bdev_get_queue(bdev); 374 if (q && q->flush_flags) 375 vbd->flush_support = true; 376 377 DPRINTK("Successful creation of handle=%04x (dom=%u)\n", 378 handle, blkif->domid); 379 return 0; 380 } 381 static int xen_blkbk_remove(struct xenbus_device *dev) 382 { 383 struct backend_info *be = dev_get_drvdata(&dev->dev); 384 385 DPRINTK(""); 386 387 if (be->major || be->minor) 388 xenvbd_sysfs_delif(dev); 389 390 if (be->backend_watch.node) { 391 unregister_xenbus_watch(&be->backend_watch); 392 kfree(be->backend_watch.node); 393 be->backend_watch.node = NULL; 394 } 395 396 if (be->blkif) { 397 xen_blkif_disconnect(be->blkif); 398 xen_vbd_free(&be->blkif->vbd); 399 xen_blkif_free(be->blkif); 400 be->blkif = NULL; 401 } 402 403 kfree(be); 404 dev_set_drvdata(&dev->dev, NULL); 405 return 0; 406 } 407 408 int xen_blkbk_flush_diskcache(struct xenbus_transaction xbt, 409 struct backend_info *be, int state) 410 { 411 struct xenbus_device *dev = be->dev; 412 int err; 413 414 err = xenbus_printf(xbt, dev->nodename, "feature-flush-cache", 415 "%d", state); 416 if (err) 417 xenbus_dev_fatal(dev, err, "writing feature-flush-cache"); 418 419 return err; 420 } 421 422 /* 423 * Entry point to this code when a new device is created. Allocate the basic 424 * structures, and watch the store waiting for the hotplug scripts to tell us 425 * the device's physical major and minor numbers. Switch to InitWait. 426 */ 427 static int xen_blkbk_probe(struct xenbus_device *dev, 428 const struct xenbus_device_id *id) 429 { 430 int err; 431 struct backend_info *be = kzalloc(sizeof(struct backend_info), 432 GFP_KERNEL); 433 if (!be) { 434 xenbus_dev_fatal(dev, -ENOMEM, 435 "allocating backend structure"); 436 return -ENOMEM; 437 } 438 be->dev = dev; 439 dev_set_drvdata(&dev->dev, be); 440 441 be->blkif = xen_blkif_alloc(dev->otherend_id); 442 if (IS_ERR(be->blkif)) { 443 err = PTR_ERR(be->blkif); 444 be->blkif = NULL; 445 xenbus_dev_fatal(dev, err, "creating block interface"); 446 goto fail; 447 } 448 449 /* setup back pointer */ 450 be->blkif->be = be; 451 452 err = xenbus_watch_pathfmt(dev, &be->backend_watch, backend_changed, 453 "%s/%s", dev->nodename, "physical-device"); 454 if (err) 455 goto fail; 456 457 err = xenbus_switch_state(dev, XenbusStateInitWait); 458 if (err) 459 goto fail; 460 461 return 0; 462 463 fail: 464 DPRINTK("failed"); 465 xen_blkbk_remove(dev); 466 return err; 467 } 468 469 470 /* 471 * Callback received when the hotplug scripts have placed the physical-device 472 * node. Read it and the mode node, and create a vbd. If the frontend is 473 * ready, connect. 474 */ 475 static void backend_changed(struct xenbus_watch *watch, 476 const char **vec, unsigned int len) 477 { 478 int err; 479 unsigned major; 480 unsigned minor; 481 struct backend_info *be 482 = container_of(watch, struct backend_info, backend_watch); 483 struct xenbus_device *dev = be->dev; 484 int cdrom = 0; 485 char *device_type; 486 487 DPRINTK(""); 488 489 err = xenbus_scanf(XBT_NIL, dev->nodename, "physical-device", "%x:%x", 490 &major, &minor); 491 if (XENBUS_EXIST_ERR(err)) { 492 /* 493 * Since this watch will fire once immediately after it is 494 * registered, we expect this. Ignore it, and wait for the 495 * hotplug scripts. 496 */ 497 return; 498 } 499 if (err != 2) { 500 xenbus_dev_fatal(dev, err, "reading physical-device"); 501 return; 502 } 503 504 if ((be->major || be->minor) && 505 ((be->major != major) || (be->minor != minor))) { 506 pr_warn(DRV_PFX "changing physical device (from %x:%x to %x:%x) not supported.\n", 507 be->major, be->minor, major, minor); 508 return; 509 } 510 511 be->mode = xenbus_read(XBT_NIL, dev->nodename, "mode", NULL); 512 if (IS_ERR(be->mode)) { 513 err = PTR_ERR(be->mode); 514 be->mode = NULL; 515 xenbus_dev_fatal(dev, err, "reading mode"); 516 return; 517 } 518 519 device_type = xenbus_read(XBT_NIL, dev->otherend, "device-type", NULL); 520 if (!IS_ERR(device_type)) { 521 cdrom = strcmp(device_type, "cdrom") == 0; 522 kfree(device_type); 523 } 524 525 if (be->major == 0 && be->minor == 0) { 526 /* Front end dir is a number, which is used as the handle. */ 527 528 char *p = strrchr(dev->otherend, '/') + 1; 529 long handle; 530 err = strict_strtoul(p, 0, &handle); 531 if (err) 532 return; 533 534 be->major = major; 535 be->minor = minor; 536 537 err = xen_vbd_create(be->blkif, handle, major, minor, 538 (NULL == strchr(be->mode, 'w')), cdrom); 539 if (err) { 540 be->major = 0; 541 be->minor = 0; 542 xenbus_dev_fatal(dev, err, "creating vbd structure"); 543 return; 544 } 545 546 err = xenvbd_sysfs_addif(dev); 547 if (err) { 548 xen_vbd_free(&be->blkif->vbd); 549 be->major = 0; 550 be->minor = 0; 551 xenbus_dev_fatal(dev, err, "creating sysfs entries"); 552 return; 553 } 554 555 /* We're potentially connected now */ 556 xen_update_blkif_status(be->blkif); 557 } 558 } 559 560 561 /* 562 * Callback received when the frontend's state changes. 563 */ 564 static void frontend_changed(struct xenbus_device *dev, 565 enum xenbus_state frontend_state) 566 { 567 struct backend_info *be = dev_get_drvdata(&dev->dev); 568 int err; 569 570 DPRINTK("%s", xenbus_strstate(frontend_state)); 571 572 switch (frontend_state) { 573 case XenbusStateInitialising: 574 if (dev->state == XenbusStateClosed) { 575 pr_info(DRV_PFX "%s: prepare for reconnect\n", 576 dev->nodename); 577 xenbus_switch_state(dev, XenbusStateInitWait); 578 } 579 break; 580 581 case XenbusStateInitialised: 582 case XenbusStateConnected: 583 /* 584 * Ensure we connect even when two watches fire in 585 * close successsion and we miss the intermediate value 586 * of frontend_state. 587 */ 588 if (dev->state == XenbusStateConnected) 589 break; 590 591 /* 592 * Enforce precondition before potential leak point. 593 * blkif_disconnect() is idempotent. 594 */ 595 xen_blkif_disconnect(be->blkif); 596 597 err = connect_ring(be); 598 if (err) 599 break; 600 xen_update_blkif_status(be->blkif); 601 break; 602 603 case XenbusStateClosing: 604 xen_blkif_disconnect(be->blkif); 605 xenbus_switch_state(dev, XenbusStateClosing); 606 break; 607 608 case XenbusStateClosed: 609 xenbus_switch_state(dev, XenbusStateClosed); 610 if (xenbus_dev_is_online(dev)) 611 break; 612 /* fall through if not online */ 613 case XenbusStateUnknown: 614 /* implies blkif_disconnect() via blkback_remove() */ 615 device_unregister(&dev->dev); 616 break; 617 618 default: 619 xenbus_dev_fatal(dev, -EINVAL, "saw state %d at frontend", 620 frontend_state); 621 break; 622 } 623 } 624 625 626 /* ** Connection ** */ 627 628 629 /* 630 * Write the physical details regarding the block device to the store, and 631 * switch to Connected state. 632 */ 633 static void connect(struct backend_info *be) 634 { 635 struct xenbus_transaction xbt; 636 int err; 637 struct xenbus_device *dev = be->dev; 638 639 DPRINTK("%s", dev->otherend); 640 641 /* Supply the information about the device the frontend needs */ 642 again: 643 err = xenbus_transaction_start(&xbt); 644 if (err) { 645 xenbus_dev_fatal(dev, err, "starting transaction"); 646 return; 647 } 648 649 err = xen_blkbk_flush_diskcache(xbt, be, be->blkif->vbd.flush_support); 650 if (err) 651 goto abort; 652 653 err = xenbus_printf(xbt, dev->nodename, "sectors", "%llu", 654 (unsigned long long)vbd_sz(&be->blkif->vbd)); 655 if (err) { 656 xenbus_dev_fatal(dev, err, "writing %s/sectors", 657 dev->nodename); 658 goto abort; 659 } 660 661 /* FIXME: use a typename instead */ 662 err = xenbus_printf(xbt, dev->nodename, "info", "%u", 663 be->blkif->vbd.type | 664 (be->blkif->vbd.readonly ? VDISK_READONLY : 0)); 665 if (err) { 666 xenbus_dev_fatal(dev, err, "writing %s/info", 667 dev->nodename); 668 goto abort; 669 } 670 err = xenbus_printf(xbt, dev->nodename, "sector-size", "%lu", 671 (unsigned long) 672 bdev_logical_block_size(be->blkif->vbd.bdev)); 673 if (err) { 674 xenbus_dev_fatal(dev, err, "writing %s/sector-size", 675 dev->nodename); 676 goto abort; 677 } 678 679 err = xenbus_transaction_end(xbt, 0); 680 if (err == -EAGAIN) 681 goto again; 682 if (err) 683 xenbus_dev_fatal(dev, err, "ending transaction"); 684 685 err = xenbus_switch_state(dev, XenbusStateConnected); 686 if (err) 687 xenbus_dev_fatal(dev, err, "%s: switching to Connected state", 688 dev->nodename); 689 690 return; 691 abort: 692 xenbus_transaction_end(xbt, 1); 693 } 694 695 696 static int connect_ring(struct backend_info *be) 697 { 698 struct xenbus_device *dev = be->dev; 699 unsigned long ring_ref; 700 unsigned int evtchn; 701 char protocol[64] = ""; 702 int err; 703 704 DPRINTK("%s", dev->otherend); 705 706 err = xenbus_gather(XBT_NIL, dev->otherend, "ring-ref", "%lu", 707 &ring_ref, "event-channel", "%u", &evtchn, NULL); 708 if (err) { 709 xenbus_dev_fatal(dev, err, 710 "reading %s/ring-ref and event-channel", 711 dev->otherend); 712 return err; 713 } 714 715 be->blkif->blk_protocol = BLKIF_PROTOCOL_NATIVE; 716 err = xenbus_gather(XBT_NIL, dev->otherend, "protocol", 717 "%63s", protocol, NULL); 718 if (err) 719 strcpy(protocol, "unspecified, assuming native"); 720 else if (0 == strcmp(protocol, XEN_IO_PROTO_ABI_NATIVE)) 721 be->blkif->blk_protocol = BLKIF_PROTOCOL_NATIVE; 722 else if (0 == strcmp(protocol, XEN_IO_PROTO_ABI_X86_32)) 723 be->blkif->blk_protocol = BLKIF_PROTOCOL_X86_32; 724 else if (0 == strcmp(protocol, XEN_IO_PROTO_ABI_X86_64)) 725 be->blkif->blk_protocol = BLKIF_PROTOCOL_X86_64; 726 else { 727 xenbus_dev_fatal(dev, err, "unknown fe protocol %s", protocol); 728 return -1; 729 } 730 pr_info(DRV_PFX "ring-ref %ld, event-channel %d, protocol %d (%s)\n", 731 ring_ref, evtchn, be->blkif->blk_protocol, protocol); 732 733 /* Map the shared frame, irq etc. */ 734 err = xen_blkif_map(be->blkif, ring_ref, evtchn); 735 if (err) { 736 xenbus_dev_fatal(dev, err, "mapping ring-ref %lu port %u", 737 ring_ref, evtchn); 738 return err; 739 } 740 741 return 0; 742 } 743 744 745 /* ** Driver Registration ** */ 746 747 748 static const struct xenbus_device_id xen_blkbk_ids[] = { 749 { "vbd" }, 750 { "" } 751 }; 752 753 754 static struct xenbus_driver xen_blkbk = { 755 .name = "vbd", 756 .owner = THIS_MODULE, 757 .ids = xen_blkbk_ids, 758 .probe = xen_blkbk_probe, 759 .remove = xen_blkbk_remove, 760 .otherend_changed = frontend_changed 761 }; 762 763 764 int xen_blkif_xenbus_init(void) 765 { 766 return xenbus_register_backend(&xen_blkbk); 767 } 768