1 /* 2 * blkfront.c 3 * 4 * XenLinux virtual block device driver. 5 * 6 * Copyright (c) 2003-2004, Keir Fraser & Steve Hand 7 * Modifications by Mark A. Williamson are (c) Intel Research Cambridge 8 * Copyright (c) 2004, Christian Limpach 9 * Copyright (c) 2004, Andrew Warfield 10 * Copyright (c) 2005, Christopher Clark 11 * Copyright (c) 2005, XenSource Ltd 12 * 13 * This program is free software; you can redistribute it and/or 14 * modify it under the terms of the GNU General Public License version 2 15 * as published by the Free Software Foundation; or, when distributed 16 * separately from the Linux kernel or incorporated into other 17 * software packages, subject to the following license: 18 * 19 * Permission is hereby granted, free of charge, to any person obtaining a copy 20 * of this source file (the "Software"), to deal in the Software without 21 * restriction, including without limitation the rights to use, copy, modify, 22 * merge, publish, distribute, sublicense, and/or sell copies of the Software, 23 * and to permit persons to whom the Software is furnished to do so, subject to 24 * the following conditions: 25 * 26 * The above copyright notice and this permission notice shall be included in 27 * all copies or substantial portions of the Software. 28 * 29 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 30 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 31 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 32 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 33 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING 34 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS 35 * IN THE SOFTWARE. 36 */ 37 38 #include <linux/interrupt.h> 39 #include <linux/blkdev.h> 40 #include <linux/hdreg.h> 41 #include <linux/cdrom.h> 42 #include <linux/module.h> 43 #include <linux/slab.h> 44 #include <linux/mutex.h> 45 #include <linux/scatterlist.h> 46 #include <linux/bitmap.h> 47 #include <linux/list.h> 48 49 #include <xen/xen.h> 50 #include <xen/xenbus.h> 51 #include <xen/grant_table.h> 52 #include <xen/events.h> 53 #include <xen/page.h> 54 #include <xen/platform_pci.h> 55 56 #include <xen/interface/grant_table.h> 57 #include <xen/interface/io/blkif.h> 58 #include <xen/interface/io/protocols.h> 59 60 #include <asm/xen/hypervisor.h> 61 62 enum blkif_state { 63 BLKIF_STATE_DISCONNECTED, 64 BLKIF_STATE_CONNECTED, 65 BLKIF_STATE_SUSPENDED, 66 }; 67 68 struct grant { 69 grant_ref_t gref; 70 unsigned long pfn; 71 struct list_head node; 72 }; 73 74 struct blk_shadow { 75 struct blkif_request req; 76 struct request *request; 77 struct grant **grants_used; 78 struct grant **indirect_grants; 79 struct scatterlist *sg; 80 }; 81 82 struct split_bio { 83 struct bio *bio; 84 atomic_t pending; 85 int err; 86 }; 87 88 static DEFINE_MUTEX(blkfront_mutex); 89 static const struct block_device_operations xlvbd_block_fops; 90 91 /* 92 * Maximum number of segments in indirect requests, the actual value used by 93 * the frontend driver is the minimum of this value and the value provided 94 * by the backend driver. 95 */ 96 97 static unsigned int xen_blkif_max_segments = 32; 98 module_param_named(max, xen_blkif_max_segments, int, S_IRUGO); 99 MODULE_PARM_DESC(max, "Maximum amount of segments in indirect requests (default is 32)"); 100 101 #define BLK_RING_SIZE __CONST_RING_SIZE(blkif, PAGE_SIZE) 102 103 /* 104 * We have one of these per vbd, whether ide, scsi or 'other'. They 105 * hang in private_data off the gendisk structure. We may end up 106 * putting all kinds of interesting stuff here :-) 107 */ 108 struct blkfront_info 109 { 110 spinlock_t io_lock; 111 struct mutex mutex; 112 struct xenbus_device *xbdev; 113 struct gendisk *gd; 114 int vdevice; 115 blkif_vdev_t handle; 116 enum blkif_state connected; 117 int ring_ref; 118 struct blkif_front_ring ring; 119 unsigned int evtchn, irq; 120 struct request_queue *rq; 121 struct work_struct work; 122 struct gnttab_free_callback callback; 123 struct blk_shadow shadow[BLK_RING_SIZE]; 124 struct list_head persistent_gnts; 125 unsigned int persistent_gnts_c; 126 unsigned long shadow_free; 127 unsigned int feature_flush; 128 unsigned int flush_op; 129 unsigned int feature_discard:1; 130 unsigned int feature_secdiscard:1; 131 unsigned int discard_granularity; 132 unsigned int discard_alignment; 133 unsigned int feature_persistent:1; 134 unsigned int max_indirect_segments; 135 int is_ready; 136 }; 137 138 static unsigned int nr_minors; 139 static unsigned long *minors; 140 static DEFINE_SPINLOCK(minor_lock); 141 142 #define MAXIMUM_OUTSTANDING_BLOCK_REQS \ 143 (BLKIF_MAX_SEGMENTS_PER_REQUEST * BLK_RING_SIZE) 144 #define GRANT_INVALID_REF 0 145 146 #define PARTS_PER_DISK 16 147 #define PARTS_PER_EXT_DISK 256 148 149 #define BLKIF_MAJOR(dev) ((dev)>>8) 150 #define BLKIF_MINOR(dev) ((dev) & 0xff) 151 152 #define EXT_SHIFT 28 153 #define EXTENDED (1<<EXT_SHIFT) 154 #define VDEV_IS_EXTENDED(dev) ((dev)&(EXTENDED)) 155 #define BLKIF_MINOR_EXT(dev) ((dev)&(~EXTENDED)) 156 #define EMULATED_HD_DISK_MINOR_OFFSET (0) 157 #define EMULATED_HD_DISK_NAME_OFFSET (EMULATED_HD_DISK_MINOR_OFFSET / 256) 158 #define EMULATED_SD_DISK_MINOR_OFFSET (0) 159 #define EMULATED_SD_DISK_NAME_OFFSET (EMULATED_SD_DISK_MINOR_OFFSET / 256) 160 161 #define DEV_NAME "xvd" /* name in /dev */ 162 163 #define SEGS_PER_INDIRECT_FRAME \ 164 (PAGE_SIZE/sizeof(struct blkif_request_segment_aligned)) 165 #define INDIRECT_GREFS(_segs) \ 166 ((_segs + SEGS_PER_INDIRECT_FRAME - 1)/SEGS_PER_INDIRECT_FRAME) 167 168 static int blkfront_setup_indirect(struct blkfront_info *info); 169 170 static int get_id_from_freelist(struct blkfront_info *info) 171 { 172 unsigned long free = info->shadow_free; 173 BUG_ON(free >= BLK_RING_SIZE); 174 info->shadow_free = info->shadow[free].req.u.rw.id; 175 info->shadow[free].req.u.rw.id = 0x0fffffee; /* debug */ 176 return free; 177 } 178 179 static int add_id_to_freelist(struct blkfront_info *info, 180 unsigned long id) 181 { 182 if (info->shadow[id].req.u.rw.id != id) 183 return -EINVAL; 184 if (info->shadow[id].request == NULL) 185 return -EINVAL; 186 info->shadow[id].req.u.rw.id = info->shadow_free; 187 info->shadow[id].request = NULL; 188 info->shadow_free = id; 189 return 0; 190 } 191 192 static int fill_grant_buffer(struct blkfront_info *info, int num) 193 { 194 struct page *granted_page; 195 struct grant *gnt_list_entry, *n; 196 int i = 0; 197 198 while(i < num) { 199 gnt_list_entry = kzalloc(sizeof(struct grant), GFP_NOIO); 200 if (!gnt_list_entry) 201 goto out_of_memory; 202 203 granted_page = alloc_page(GFP_NOIO); 204 if (!granted_page) { 205 kfree(gnt_list_entry); 206 goto out_of_memory; 207 } 208 209 gnt_list_entry->pfn = page_to_pfn(granted_page); 210 gnt_list_entry->gref = GRANT_INVALID_REF; 211 list_add(&gnt_list_entry->node, &info->persistent_gnts); 212 i++; 213 } 214 215 return 0; 216 217 out_of_memory: 218 list_for_each_entry_safe(gnt_list_entry, n, 219 &info->persistent_gnts, node) { 220 list_del(&gnt_list_entry->node); 221 __free_page(pfn_to_page(gnt_list_entry->pfn)); 222 kfree(gnt_list_entry); 223 i--; 224 } 225 BUG_ON(i != 0); 226 return -ENOMEM; 227 } 228 229 static struct grant *get_grant(grant_ref_t *gref_head, 230 struct blkfront_info *info) 231 { 232 struct grant *gnt_list_entry; 233 unsigned long buffer_mfn; 234 235 BUG_ON(list_empty(&info->persistent_gnts)); 236 gnt_list_entry = list_first_entry(&info->persistent_gnts, struct grant, 237 node); 238 list_del(&gnt_list_entry->node); 239 240 if (gnt_list_entry->gref != GRANT_INVALID_REF) { 241 info->persistent_gnts_c--; 242 return gnt_list_entry; 243 } 244 245 /* Assign a gref to this page */ 246 gnt_list_entry->gref = gnttab_claim_grant_reference(gref_head); 247 BUG_ON(gnt_list_entry->gref == -ENOSPC); 248 buffer_mfn = pfn_to_mfn(gnt_list_entry->pfn); 249 gnttab_grant_foreign_access_ref(gnt_list_entry->gref, 250 info->xbdev->otherend_id, 251 buffer_mfn, 0); 252 return gnt_list_entry; 253 } 254 255 static const char *op_name(int op) 256 { 257 static const char *const names[] = { 258 [BLKIF_OP_READ] = "read", 259 [BLKIF_OP_WRITE] = "write", 260 [BLKIF_OP_WRITE_BARRIER] = "barrier", 261 [BLKIF_OP_FLUSH_DISKCACHE] = "flush", 262 [BLKIF_OP_DISCARD] = "discard" }; 263 264 if (op < 0 || op >= ARRAY_SIZE(names)) 265 return "unknown"; 266 267 if (!names[op]) 268 return "reserved"; 269 270 return names[op]; 271 } 272 static int xlbd_reserve_minors(unsigned int minor, unsigned int nr) 273 { 274 unsigned int end = minor + nr; 275 int rc; 276 277 if (end > nr_minors) { 278 unsigned long *bitmap, *old; 279 280 bitmap = kcalloc(BITS_TO_LONGS(end), sizeof(*bitmap), 281 GFP_KERNEL); 282 if (bitmap == NULL) 283 return -ENOMEM; 284 285 spin_lock(&minor_lock); 286 if (end > nr_minors) { 287 old = minors; 288 memcpy(bitmap, minors, 289 BITS_TO_LONGS(nr_minors) * sizeof(*bitmap)); 290 minors = bitmap; 291 nr_minors = BITS_TO_LONGS(end) * BITS_PER_LONG; 292 } else 293 old = bitmap; 294 spin_unlock(&minor_lock); 295 kfree(old); 296 } 297 298 spin_lock(&minor_lock); 299 if (find_next_bit(minors, end, minor) >= end) { 300 bitmap_set(minors, minor, nr); 301 rc = 0; 302 } else 303 rc = -EBUSY; 304 spin_unlock(&minor_lock); 305 306 return rc; 307 } 308 309 static void xlbd_release_minors(unsigned int minor, unsigned int nr) 310 { 311 unsigned int end = minor + nr; 312 313 BUG_ON(end > nr_minors); 314 spin_lock(&minor_lock); 315 bitmap_clear(minors, minor, nr); 316 spin_unlock(&minor_lock); 317 } 318 319 static void blkif_restart_queue_callback(void *arg) 320 { 321 struct blkfront_info *info = (struct blkfront_info *)arg; 322 schedule_work(&info->work); 323 } 324 325 static int blkif_getgeo(struct block_device *bd, struct hd_geometry *hg) 326 { 327 /* We don't have real geometry info, but let's at least return 328 values consistent with the size of the device */ 329 sector_t nsect = get_capacity(bd->bd_disk); 330 sector_t cylinders = nsect; 331 332 hg->heads = 0xff; 333 hg->sectors = 0x3f; 334 sector_div(cylinders, hg->heads * hg->sectors); 335 hg->cylinders = cylinders; 336 if ((sector_t)(hg->cylinders + 1) * hg->heads * hg->sectors < nsect) 337 hg->cylinders = 0xffff; 338 return 0; 339 } 340 341 static int blkif_ioctl(struct block_device *bdev, fmode_t mode, 342 unsigned command, unsigned long argument) 343 { 344 struct blkfront_info *info = bdev->bd_disk->private_data; 345 int i; 346 347 dev_dbg(&info->xbdev->dev, "command: 0x%x, argument: 0x%lx\n", 348 command, (long)argument); 349 350 switch (command) { 351 case CDROMMULTISESSION: 352 dev_dbg(&info->xbdev->dev, "FIXME: support multisession CDs later\n"); 353 for (i = 0; i < sizeof(struct cdrom_multisession); i++) 354 if (put_user(0, (char __user *)(argument + i))) 355 return -EFAULT; 356 return 0; 357 358 case CDROM_GET_CAPABILITY: { 359 struct gendisk *gd = info->gd; 360 if (gd->flags & GENHD_FL_CD) 361 return 0; 362 return -EINVAL; 363 } 364 365 default: 366 /*printk(KERN_ALERT "ioctl %08x not supported by Xen blkdev\n", 367 command);*/ 368 return -EINVAL; /* same return as native Linux */ 369 } 370 371 return 0; 372 } 373 374 /* 375 * Generate a Xen blkfront IO request from a blk layer request. Reads 376 * and writes are handled as expected. 377 * 378 * @req: a request struct 379 */ 380 static int blkif_queue_request(struct request *req) 381 { 382 struct blkfront_info *info = req->rq_disk->private_data; 383 struct blkif_request *ring_req; 384 unsigned long id; 385 unsigned int fsect, lsect; 386 int i, ref, n; 387 struct blkif_request_segment_aligned *segments = NULL; 388 389 /* 390 * Used to store if we are able to queue the request by just using 391 * existing persistent grants, or if we have to get new grants, 392 * as there are not sufficiently many free. 393 */ 394 bool new_persistent_gnts; 395 grant_ref_t gref_head; 396 struct grant *gnt_list_entry = NULL; 397 struct scatterlist *sg; 398 int nseg, max_grefs; 399 400 if (unlikely(info->connected != BLKIF_STATE_CONNECTED)) 401 return 1; 402 403 max_grefs = info->max_indirect_segments ? 404 info->max_indirect_segments + 405 INDIRECT_GREFS(info->max_indirect_segments) : 406 BLKIF_MAX_SEGMENTS_PER_REQUEST; 407 408 /* Check if we have enough grants to allocate a requests */ 409 if (info->persistent_gnts_c < max_grefs) { 410 new_persistent_gnts = 1; 411 if (gnttab_alloc_grant_references( 412 max_grefs - info->persistent_gnts_c, 413 &gref_head) < 0) { 414 gnttab_request_free_callback( 415 &info->callback, 416 blkif_restart_queue_callback, 417 info, 418 max_grefs); 419 return 1; 420 } 421 } else 422 new_persistent_gnts = 0; 423 424 /* Fill out a communications ring structure. */ 425 ring_req = RING_GET_REQUEST(&info->ring, info->ring.req_prod_pvt); 426 id = get_id_from_freelist(info); 427 info->shadow[id].request = req; 428 429 if (unlikely(req->cmd_flags & (REQ_DISCARD | REQ_SECURE))) { 430 ring_req->operation = BLKIF_OP_DISCARD; 431 ring_req->u.discard.nr_sectors = blk_rq_sectors(req); 432 ring_req->u.discard.id = id; 433 ring_req->u.discard.sector_number = (blkif_sector_t)blk_rq_pos(req); 434 if ((req->cmd_flags & REQ_SECURE) && info->feature_secdiscard) 435 ring_req->u.discard.flag = BLKIF_DISCARD_SECURE; 436 else 437 ring_req->u.discard.flag = 0; 438 } else { 439 BUG_ON(info->max_indirect_segments == 0 && 440 req->nr_phys_segments > BLKIF_MAX_SEGMENTS_PER_REQUEST); 441 BUG_ON(info->max_indirect_segments && 442 req->nr_phys_segments > info->max_indirect_segments); 443 nseg = blk_rq_map_sg(req->q, req, info->shadow[id].sg); 444 ring_req->u.rw.id = id; 445 if (nseg > BLKIF_MAX_SEGMENTS_PER_REQUEST) { 446 /* 447 * The indirect operation can only be a BLKIF_OP_READ or 448 * BLKIF_OP_WRITE 449 */ 450 BUG_ON(req->cmd_flags & (REQ_FLUSH | REQ_FUA)); 451 ring_req->operation = BLKIF_OP_INDIRECT; 452 ring_req->u.indirect.indirect_op = rq_data_dir(req) ? 453 BLKIF_OP_WRITE : BLKIF_OP_READ; 454 ring_req->u.indirect.sector_number = (blkif_sector_t)blk_rq_pos(req); 455 ring_req->u.indirect.handle = info->handle; 456 ring_req->u.indirect.nr_segments = nseg; 457 } else { 458 ring_req->u.rw.sector_number = (blkif_sector_t)blk_rq_pos(req); 459 ring_req->u.rw.handle = info->handle; 460 ring_req->operation = rq_data_dir(req) ? 461 BLKIF_OP_WRITE : BLKIF_OP_READ; 462 if (req->cmd_flags & (REQ_FLUSH | REQ_FUA)) { 463 /* 464 * Ideally we can do an unordered flush-to-disk. In case the 465 * backend onlysupports barriers, use that. A barrier request 466 * a superset of FUA, so we can implement it the same 467 * way. (It's also a FLUSH+FUA, since it is 468 * guaranteed ordered WRT previous writes.) 469 */ 470 ring_req->operation = info->flush_op; 471 } 472 ring_req->u.rw.nr_segments = nseg; 473 } 474 for_each_sg(info->shadow[id].sg, sg, nseg, i) { 475 fsect = sg->offset >> 9; 476 lsect = fsect + (sg->length >> 9) - 1; 477 478 if ((ring_req->operation == BLKIF_OP_INDIRECT) && 479 (i % SEGS_PER_INDIRECT_FRAME == 0)) { 480 if (segments) 481 kunmap_atomic(segments); 482 483 n = i / SEGS_PER_INDIRECT_FRAME; 484 gnt_list_entry = get_grant(&gref_head, info); 485 info->shadow[id].indirect_grants[n] = gnt_list_entry; 486 segments = kmap_atomic(pfn_to_page(gnt_list_entry->pfn)); 487 ring_req->u.indirect.indirect_grefs[n] = gnt_list_entry->gref; 488 } 489 490 gnt_list_entry = get_grant(&gref_head, info); 491 ref = gnt_list_entry->gref; 492 493 info->shadow[id].grants_used[i] = gnt_list_entry; 494 495 if (rq_data_dir(req)) { 496 char *bvec_data; 497 void *shared_data; 498 499 BUG_ON(sg->offset + sg->length > PAGE_SIZE); 500 501 shared_data = kmap_atomic(pfn_to_page(gnt_list_entry->pfn)); 502 bvec_data = kmap_atomic(sg_page(sg)); 503 504 /* 505 * this does not wipe data stored outside the 506 * range sg->offset..sg->offset+sg->length. 507 * Therefore, blkback *could* see data from 508 * previous requests. This is OK as long as 509 * persistent grants are shared with just one 510 * domain. It may need refactoring if this 511 * changes 512 */ 513 memcpy(shared_data + sg->offset, 514 bvec_data + sg->offset, 515 sg->length); 516 517 kunmap_atomic(bvec_data); 518 kunmap_atomic(shared_data); 519 } 520 if (ring_req->operation != BLKIF_OP_INDIRECT) { 521 ring_req->u.rw.seg[i] = 522 (struct blkif_request_segment) { 523 .gref = ref, 524 .first_sect = fsect, 525 .last_sect = lsect }; 526 } else { 527 n = i % SEGS_PER_INDIRECT_FRAME; 528 segments[n] = 529 (struct blkif_request_segment_aligned) { 530 .gref = ref, 531 .first_sect = fsect, 532 .last_sect = lsect }; 533 } 534 } 535 if (segments) 536 kunmap_atomic(segments); 537 } 538 539 info->ring.req_prod_pvt++; 540 541 /* Keep a private copy so we can reissue requests when recovering. */ 542 info->shadow[id].req = *ring_req; 543 544 if (new_persistent_gnts) 545 gnttab_free_grant_references(gref_head); 546 547 return 0; 548 } 549 550 551 static inline void flush_requests(struct blkfront_info *info) 552 { 553 int notify; 554 555 RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&info->ring, notify); 556 557 if (notify) 558 notify_remote_via_irq(info->irq); 559 } 560 561 /* 562 * do_blkif_request 563 * read a block; request is in a request queue 564 */ 565 static void do_blkif_request(struct request_queue *rq) 566 { 567 struct blkfront_info *info = NULL; 568 struct request *req; 569 int queued; 570 571 pr_debug("Entered do_blkif_request\n"); 572 573 queued = 0; 574 575 while ((req = blk_peek_request(rq)) != NULL) { 576 info = req->rq_disk->private_data; 577 578 if (RING_FULL(&info->ring)) 579 goto wait; 580 581 blk_start_request(req); 582 583 if ((req->cmd_type != REQ_TYPE_FS) || 584 ((req->cmd_flags & (REQ_FLUSH | REQ_FUA)) && 585 !info->flush_op)) { 586 __blk_end_request_all(req, -EIO); 587 continue; 588 } 589 590 pr_debug("do_blk_req %p: cmd %p, sec %lx, " 591 "(%u/%u) buffer:%p [%s]\n", 592 req, req->cmd, (unsigned long)blk_rq_pos(req), 593 blk_rq_cur_sectors(req), blk_rq_sectors(req), 594 req->buffer, rq_data_dir(req) ? "write" : "read"); 595 596 if (blkif_queue_request(req)) { 597 blk_requeue_request(rq, req); 598 wait: 599 /* Avoid pointless unplugs. */ 600 blk_stop_queue(rq); 601 break; 602 } 603 604 queued++; 605 } 606 607 if (queued != 0) 608 flush_requests(info); 609 } 610 611 static int xlvbd_init_blk_queue(struct gendisk *gd, u16 sector_size, 612 unsigned int physical_sector_size, 613 unsigned int segments) 614 { 615 struct request_queue *rq; 616 struct blkfront_info *info = gd->private_data; 617 618 rq = blk_init_queue(do_blkif_request, &info->io_lock); 619 if (rq == NULL) 620 return -1; 621 622 queue_flag_set_unlocked(QUEUE_FLAG_VIRT, rq); 623 624 if (info->feature_discard) { 625 queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, rq); 626 blk_queue_max_discard_sectors(rq, get_capacity(gd)); 627 rq->limits.discard_granularity = info->discard_granularity; 628 rq->limits.discard_alignment = info->discard_alignment; 629 if (info->feature_secdiscard) 630 queue_flag_set_unlocked(QUEUE_FLAG_SECDISCARD, rq); 631 } 632 633 /* Hard sector size and max sectors impersonate the equiv. hardware. */ 634 blk_queue_logical_block_size(rq, sector_size); 635 blk_queue_physical_block_size(rq, physical_sector_size); 636 blk_queue_max_hw_sectors(rq, (segments * PAGE_SIZE) / 512); 637 638 /* Each segment in a request is up to an aligned page in size. */ 639 blk_queue_segment_boundary(rq, PAGE_SIZE - 1); 640 blk_queue_max_segment_size(rq, PAGE_SIZE); 641 642 /* Ensure a merged request will fit in a single I/O ring slot. */ 643 blk_queue_max_segments(rq, segments); 644 645 /* Make sure buffer addresses are sector-aligned. */ 646 blk_queue_dma_alignment(rq, 511); 647 648 /* Make sure we don't use bounce buffers. */ 649 blk_queue_bounce_limit(rq, BLK_BOUNCE_ANY); 650 651 gd->queue = rq; 652 653 return 0; 654 } 655 656 657 static void xlvbd_flush(struct blkfront_info *info) 658 { 659 blk_queue_flush(info->rq, info->feature_flush); 660 printk(KERN_INFO "blkfront: %s: %s: %s %s %s %s %s\n", 661 info->gd->disk_name, 662 info->flush_op == BLKIF_OP_WRITE_BARRIER ? 663 "barrier" : (info->flush_op == BLKIF_OP_FLUSH_DISKCACHE ? 664 "flush diskcache" : "barrier or flush"), 665 info->feature_flush ? "enabled;" : "disabled;", 666 "persistent grants:", 667 info->feature_persistent ? "enabled;" : "disabled;", 668 "indirect descriptors:", 669 info->max_indirect_segments ? "enabled;" : "disabled;"); 670 } 671 672 static int xen_translate_vdev(int vdevice, int *minor, unsigned int *offset) 673 { 674 int major; 675 major = BLKIF_MAJOR(vdevice); 676 *minor = BLKIF_MINOR(vdevice); 677 switch (major) { 678 case XEN_IDE0_MAJOR: 679 *offset = (*minor / 64) + EMULATED_HD_DISK_NAME_OFFSET; 680 *minor = ((*minor / 64) * PARTS_PER_DISK) + 681 EMULATED_HD_DISK_MINOR_OFFSET; 682 break; 683 case XEN_IDE1_MAJOR: 684 *offset = (*minor / 64) + 2 + EMULATED_HD_DISK_NAME_OFFSET; 685 *minor = (((*minor / 64) + 2) * PARTS_PER_DISK) + 686 EMULATED_HD_DISK_MINOR_OFFSET; 687 break; 688 case XEN_SCSI_DISK0_MAJOR: 689 *offset = (*minor / PARTS_PER_DISK) + EMULATED_SD_DISK_NAME_OFFSET; 690 *minor = *minor + EMULATED_SD_DISK_MINOR_OFFSET; 691 break; 692 case XEN_SCSI_DISK1_MAJOR: 693 case XEN_SCSI_DISK2_MAJOR: 694 case XEN_SCSI_DISK3_MAJOR: 695 case XEN_SCSI_DISK4_MAJOR: 696 case XEN_SCSI_DISK5_MAJOR: 697 case XEN_SCSI_DISK6_MAJOR: 698 case XEN_SCSI_DISK7_MAJOR: 699 *offset = (*minor / PARTS_PER_DISK) + 700 ((major - XEN_SCSI_DISK1_MAJOR + 1) * 16) + 701 EMULATED_SD_DISK_NAME_OFFSET; 702 *minor = *minor + 703 ((major - XEN_SCSI_DISK1_MAJOR + 1) * 16 * PARTS_PER_DISK) + 704 EMULATED_SD_DISK_MINOR_OFFSET; 705 break; 706 case XEN_SCSI_DISK8_MAJOR: 707 case XEN_SCSI_DISK9_MAJOR: 708 case XEN_SCSI_DISK10_MAJOR: 709 case XEN_SCSI_DISK11_MAJOR: 710 case XEN_SCSI_DISK12_MAJOR: 711 case XEN_SCSI_DISK13_MAJOR: 712 case XEN_SCSI_DISK14_MAJOR: 713 case XEN_SCSI_DISK15_MAJOR: 714 *offset = (*minor / PARTS_PER_DISK) + 715 ((major - XEN_SCSI_DISK8_MAJOR + 8) * 16) + 716 EMULATED_SD_DISK_NAME_OFFSET; 717 *minor = *minor + 718 ((major - XEN_SCSI_DISK8_MAJOR + 8) * 16 * PARTS_PER_DISK) + 719 EMULATED_SD_DISK_MINOR_OFFSET; 720 break; 721 case XENVBD_MAJOR: 722 *offset = *minor / PARTS_PER_DISK; 723 break; 724 default: 725 printk(KERN_WARNING "blkfront: your disk configuration is " 726 "incorrect, please use an xvd device instead\n"); 727 return -ENODEV; 728 } 729 return 0; 730 } 731 732 static char *encode_disk_name(char *ptr, unsigned int n) 733 { 734 if (n >= 26) 735 ptr = encode_disk_name(ptr, n / 26 - 1); 736 *ptr = 'a' + n % 26; 737 return ptr + 1; 738 } 739 740 static int xlvbd_alloc_gendisk(blkif_sector_t capacity, 741 struct blkfront_info *info, 742 u16 vdisk_info, u16 sector_size, 743 unsigned int physical_sector_size) 744 { 745 struct gendisk *gd; 746 int nr_minors = 1; 747 int err; 748 unsigned int offset; 749 int minor; 750 int nr_parts; 751 char *ptr; 752 753 BUG_ON(info->gd != NULL); 754 BUG_ON(info->rq != NULL); 755 756 if ((info->vdevice>>EXT_SHIFT) > 1) { 757 /* this is above the extended range; something is wrong */ 758 printk(KERN_WARNING "blkfront: vdevice 0x%x is above the extended range; ignoring\n", info->vdevice); 759 return -ENODEV; 760 } 761 762 if (!VDEV_IS_EXTENDED(info->vdevice)) { 763 err = xen_translate_vdev(info->vdevice, &minor, &offset); 764 if (err) 765 return err; 766 nr_parts = PARTS_PER_DISK; 767 } else { 768 minor = BLKIF_MINOR_EXT(info->vdevice); 769 nr_parts = PARTS_PER_EXT_DISK; 770 offset = minor / nr_parts; 771 if (xen_hvm_domain() && offset < EMULATED_HD_DISK_NAME_OFFSET + 4) 772 printk(KERN_WARNING "blkfront: vdevice 0x%x might conflict with " 773 "emulated IDE disks,\n\t choose an xvd device name" 774 "from xvde on\n", info->vdevice); 775 } 776 if (minor >> MINORBITS) { 777 pr_warn("blkfront: %#x's minor (%#x) out of range; ignoring\n", 778 info->vdevice, minor); 779 return -ENODEV; 780 } 781 782 if ((minor % nr_parts) == 0) 783 nr_minors = nr_parts; 784 785 err = xlbd_reserve_minors(minor, nr_minors); 786 if (err) 787 goto out; 788 err = -ENODEV; 789 790 gd = alloc_disk(nr_minors); 791 if (gd == NULL) 792 goto release; 793 794 strcpy(gd->disk_name, DEV_NAME); 795 ptr = encode_disk_name(gd->disk_name + sizeof(DEV_NAME) - 1, offset); 796 BUG_ON(ptr >= gd->disk_name + DISK_NAME_LEN); 797 if (nr_minors > 1) 798 *ptr = 0; 799 else 800 snprintf(ptr, gd->disk_name + DISK_NAME_LEN - ptr, 801 "%d", minor & (nr_parts - 1)); 802 803 gd->major = XENVBD_MAJOR; 804 gd->first_minor = minor; 805 gd->fops = &xlvbd_block_fops; 806 gd->private_data = info; 807 gd->driverfs_dev = &(info->xbdev->dev); 808 set_capacity(gd, capacity); 809 810 if (xlvbd_init_blk_queue(gd, sector_size, physical_sector_size, 811 info->max_indirect_segments ? : 812 BLKIF_MAX_SEGMENTS_PER_REQUEST)) { 813 del_gendisk(gd); 814 goto release; 815 } 816 817 info->rq = gd->queue; 818 info->gd = gd; 819 820 xlvbd_flush(info); 821 822 if (vdisk_info & VDISK_READONLY) 823 set_disk_ro(gd, 1); 824 825 if (vdisk_info & VDISK_REMOVABLE) 826 gd->flags |= GENHD_FL_REMOVABLE; 827 828 if (vdisk_info & VDISK_CDROM) 829 gd->flags |= GENHD_FL_CD; 830 831 return 0; 832 833 release: 834 xlbd_release_minors(minor, nr_minors); 835 out: 836 return err; 837 } 838 839 static void xlvbd_release_gendisk(struct blkfront_info *info) 840 { 841 unsigned int minor, nr_minors; 842 unsigned long flags; 843 844 if (info->rq == NULL) 845 return; 846 847 spin_lock_irqsave(&info->io_lock, flags); 848 849 /* No more blkif_request(). */ 850 blk_stop_queue(info->rq); 851 852 /* No more gnttab callback work. */ 853 gnttab_cancel_free_callback(&info->callback); 854 spin_unlock_irqrestore(&info->io_lock, flags); 855 856 /* Flush gnttab callback work. Must be done with no locks held. */ 857 flush_work(&info->work); 858 859 del_gendisk(info->gd); 860 861 minor = info->gd->first_minor; 862 nr_minors = info->gd->minors; 863 xlbd_release_minors(minor, nr_minors); 864 865 blk_cleanup_queue(info->rq); 866 info->rq = NULL; 867 868 put_disk(info->gd); 869 info->gd = NULL; 870 } 871 872 static void kick_pending_request_queues(struct blkfront_info *info) 873 { 874 if (!RING_FULL(&info->ring)) { 875 /* Re-enable calldowns. */ 876 blk_start_queue(info->rq); 877 /* Kick things off immediately. */ 878 do_blkif_request(info->rq); 879 } 880 } 881 882 static void blkif_restart_queue(struct work_struct *work) 883 { 884 struct blkfront_info *info = container_of(work, struct blkfront_info, work); 885 886 spin_lock_irq(&info->io_lock); 887 if (info->connected == BLKIF_STATE_CONNECTED) 888 kick_pending_request_queues(info); 889 spin_unlock_irq(&info->io_lock); 890 } 891 892 static void blkif_free(struct blkfront_info *info, int suspend) 893 { 894 struct grant *persistent_gnt; 895 struct grant *n; 896 int i, j, segs; 897 898 /* Prevent new requests being issued until we fix things up. */ 899 spin_lock_irq(&info->io_lock); 900 info->connected = suspend ? 901 BLKIF_STATE_SUSPENDED : BLKIF_STATE_DISCONNECTED; 902 /* No more blkif_request(). */ 903 if (info->rq) 904 blk_stop_queue(info->rq); 905 906 /* Remove all persistent grants */ 907 if (!list_empty(&info->persistent_gnts)) { 908 list_for_each_entry_safe(persistent_gnt, n, 909 &info->persistent_gnts, node) { 910 list_del(&persistent_gnt->node); 911 if (persistent_gnt->gref != GRANT_INVALID_REF) { 912 gnttab_end_foreign_access(persistent_gnt->gref, 913 0, 0UL); 914 info->persistent_gnts_c--; 915 } 916 __free_page(pfn_to_page(persistent_gnt->pfn)); 917 kfree(persistent_gnt); 918 } 919 } 920 BUG_ON(info->persistent_gnts_c != 0); 921 922 for (i = 0; i < BLK_RING_SIZE; i++) { 923 /* 924 * Clear persistent grants present in requests already 925 * on the shared ring 926 */ 927 if (!info->shadow[i].request) 928 goto free_shadow; 929 930 segs = info->shadow[i].req.operation == BLKIF_OP_INDIRECT ? 931 info->shadow[i].req.u.indirect.nr_segments : 932 info->shadow[i].req.u.rw.nr_segments; 933 for (j = 0; j < segs; j++) { 934 persistent_gnt = info->shadow[i].grants_used[j]; 935 gnttab_end_foreign_access(persistent_gnt->gref, 0, 0UL); 936 __free_page(pfn_to_page(persistent_gnt->pfn)); 937 kfree(persistent_gnt); 938 } 939 940 if (info->shadow[i].req.operation != BLKIF_OP_INDIRECT) 941 /* 942 * If this is not an indirect operation don't try to 943 * free indirect segments 944 */ 945 goto free_shadow; 946 947 for (j = 0; j < INDIRECT_GREFS(segs); j++) { 948 persistent_gnt = info->shadow[i].indirect_grants[j]; 949 gnttab_end_foreign_access(persistent_gnt->gref, 0, 0UL); 950 __free_page(pfn_to_page(persistent_gnt->pfn)); 951 kfree(persistent_gnt); 952 } 953 954 free_shadow: 955 kfree(info->shadow[i].grants_used); 956 info->shadow[i].grants_used = NULL; 957 kfree(info->shadow[i].indirect_grants); 958 info->shadow[i].indirect_grants = NULL; 959 kfree(info->shadow[i].sg); 960 info->shadow[i].sg = NULL; 961 } 962 963 /* No more gnttab callback work. */ 964 gnttab_cancel_free_callback(&info->callback); 965 spin_unlock_irq(&info->io_lock); 966 967 /* Flush gnttab callback work. Must be done with no locks held. */ 968 flush_work(&info->work); 969 970 /* Free resources associated with old device channel. */ 971 if (info->ring_ref != GRANT_INVALID_REF) { 972 gnttab_end_foreign_access(info->ring_ref, 0, 973 (unsigned long)info->ring.sring); 974 info->ring_ref = GRANT_INVALID_REF; 975 info->ring.sring = NULL; 976 } 977 if (info->irq) 978 unbind_from_irqhandler(info->irq, info); 979 info->evtchn = info->irq = 0; 980 981 } 982 983 static void blkif_completion(struct blk_shadow *s, struct blkfront_info *info, 984 struct blkif_response *bret) 985 { 986 int i = 0; 987 struct scatterlist *sg; 988 char *bvec_data; 989 void *shared_data; 990 int nseg; 991 992 nseg = s->req.operation == BLKIF_OP_INDIRECT ? 993 s->req.u.indirect.nr_segments : s->req.u.rw.nr_segments; 994 995 if (bret->operation == BLKIF_OP_READ) { 996 /* 997 * Copy the data received from the backend into the bvec. 998 * Since bv_offset can be different than 0, and bv_len different 999 * than PAGE_SIZE, we have to keep track of the current offset, 1000 * to be sure we are copying the data from the right shared page. 1001 */ 1002 for_each_sg(s->sg, sg, nseg, i) { 1003 BUG_ON(sg->offset + sg->length > PAGE_SIZE); 1004 shared_data = kmap_atomic( 1005 pfn_to_page(s->grants_used[i]->pfn)); 1006 bvec_data = kmap_atomic(sg_page(sg)); 1007 memcpy(bvec_data + sg->offset, 1008 shared_data + sg->offset, 1009 sg->length); 1010 kunmap_atomic(bvec_data); 1011 kunmap_atomic(shared_data); 1012 } 1013 } 1014 /* Add the persistent grant into the list of free grants */ 1015 for (i = 0; i < nseg; i++) { 1016 list_add(&s->grants_used[i]->node, &info->persistent_gnts); 1017 info->persistent_gnts_c++; 1018 } 1019 if (s->req.operation == BLKIF_OP_INDIRECT) { 1020 for (i = 0; i < INDIRECT_GREFS(nseg); i++) { 1021 list_add(&s->indirect_grants[i]->node, &info->persistent_gnts); 1022 info->persistent_gnts_c++; 1023 } 1024 } 1025 } 1026 1027 static irqreturn_t blkif_interrupt(int irq, void *dev_id) 1028 { 1029 struct request *req; 1030 struct blkif_response *bret; 1031 RING_IDX i, rp; 1032 unsigned long flags; 1033 struct blkfront_info *info = (struct blkfront_info *)dev_id; 1034 int error; 1035 1036 spin_lock_irqsave(&info->io_lock, flags); 1037 1038 if (unlikely(info->connected != BLKIF_STATE_CONNECTED)) { 1039 spin_unlock_irqrestore(&info->io_lock, flags); 1040 return IRQ_HANDLED; 1041 } 1042 1043 again: 1044 rp = info->ring.sring->rsp_prod; 1045 rmb(); /* Ensure we see queued responses up to 'rp'. */ 1046 1047 for (i = info->ring.rsp_cons; i != rp; i++) { 1048 unsigned long id; 1049 1050 bret = RING_GET_RESPONSE(&info->ring, i); 1051 id = bret->id; 1052 /* 1053 * The backend has messed up and given us an id that we would 1054 * never have given to it (we stamp it up to BLK_RING_SIZE - 1055 * look in get_id_from_freelist. 1056 */ 1057 if (id >= BLK_RING_SIZE) { 1058 WARN(1, "%s: response to %s has incorrect id (%ld)\n", 1059 info->gd->disk_name, op_name(bret->operation), id); 1060 /* We can't safely get the 'struct request' as 1061 * the id is busted. */ 1062 continue; 1063 } 1064 req = info->shadow[id].request; 1065 1066 if (bret->operation != BLKIF_OP_DISCARD) 1067 blkif_completion(&info->shadow[id], info, bret); 1068 1069 if (add_id_to_freelist(info, id)) { 1070 WARN(1, "%s: response to %s (id %ld) couldn't be recycled!\n", 1071 info->gd->disk_name, op_name(bret->operation), id); 1072 continue; 1073 } 1074 1075 error = (bret->status == BLKIF_RSP_OKAY) ? 0 : -EIO; 1076 switch (bret->operation) { 1077 case BLKIF_OP_DISCARD: 1078 if (unlikely(bret->status == BLKIF_RSP_EOPNOTSUPP)) { 1079 struct request_queue *rq = info->rq; 1080 printk(KERN_WARNING "blkfront: %s: %s op failed\n", 1081 info->gd->disk_name, op_name(bret->operation)); 1082 error = -EOPNOTSUPP; 1083 info->feature_discard = 0; 1084 info->feature_secdiscard = 0; 1085 queue_flag_clear(QUEUE_FLAG_DISCARD, rq); 1086 queue_flag_clear(QUEUE_FLAG_SECDISCARD, rq); 1087 } 1088 __blk_end_request_all(req, error); 1089 break; 1090 case BLKIF_OP_FLUSH_DISKCACHE: 1091 case BLKIF_OP_WRITE_BARRIER: 1092 if (unlikely(bret->status == BLKIF_RSP_EOPNOTSUPP)) { 1093 printk(KERN_WARNING "blkfront: %s: %s op failed\n", 1094 info->gd->disk_name, op_name(bret->operation)); 1095 error = -EOPNOTSUPP; 1096 } 1097 if (unlikely(bret->status == BLKIF_RSP_ERROR && 1098 info->shadow[id].req.u.rw.nr_segments == 0)) { 1099 printk(KERN_WARNING "blkfront: %s: empty %s op failed\n", 1100 info->gd->disk_name, op_name(bret->operation)); 1101 error = -EOPNOTSUPP; 1102 } 1103 if (unlikely(error)) { 1104 if (error == -EOPNOTSUPP) 1105 error = 0; 1106 info->feature_flush = 0; 1107 info->flush_op = 0; 1108 xlvbd_flush(info); 1109 } 1110 /* fall through */ 1111 case BLKIF_OP_READ: 1112 case BLKIF_OP_WRITE: 1113 if (unlikely(bret->status != BLKIF_RSP_OKAY)) 1114 dev_dbg(&info->xbdev->dev, "Bad return from blkdev data " 1115 "request: %x\n", bret->status); 1116 1117 __blk_end_request_all(req, error); 1118 break; 1119 default: 1120 BUG(); 1121 } 1122 } 1123 1124 info->ring.rsp_cons = i; 1125 1126 if (i != info->ring.req_prod_pvt) { 1127 int more_to_do; 1128 RING_FINAL_CHECK_FOR_RESPONSES(&info->ring, more_to_do); 1129 if (more_to_do) 1130 goto again; 1131 } else 1132 info->ring.sring->rsp_event = i + 1; 1133 1134 kick_pending_request_queues(info); 1135 1136 spin_unlock_irqrestore(&info->io_lock, flags); 1137 1138 return IRQ_HANDLED; 1139 } 1140 1141 1142 static int setup_blkring(struct xenbus_device *dev, 1143 struct blkfront_info *info) 1144 { 1145 struct blkif_sring *sring; 1146 int err; 1147 1148 info->ring_ref = GRANT_INVALID_REF; 1149 1150 sring = (struct blkif_sring *)__get_free_page(GFP_NOIO | __GFP_HIGH); 1151 if (!sring) { 1152 xenbus_dev_fatal(dev, -ENOMEM, "allocating shared ring"); 1153 return -ENOMEM; 1154 } 1155 SHARED_RING_INIT(sring); 1156 FRONT_RING_INIT(&info->ring, sring, PAGE_SIZE); 1157 1158 err = xenbus_grant_ring(dev, virt_to_mfn(info->ring.sring)); 1159 if (err < 0) { 1160 free_page((unsigned long)sring); 1161 info->ring.sring = NULL; 1162 goto fail; 1163 } 1164 info->ring_ref = err; 1165 1166 err = xenbus_alloc_evtchn(dev, &info->evtchn); 1167 if (err) 1168 goto fail; 1169 1170 err = bind_evtchn_to_irqhandler(info->evtchn, blkif_interrupt, 0, 1171 "blkif", info); 1172 if (err <= 0) { 1173 xenbus_dev_fatal(dev, err, 1174 "bind_evtchn_to_irqhandler failed"); 1175 goto fail; 1176 } 1177 info->irq = err; 1178 1179 return 0; 1180 fail: 1181 blkif_free(info, 0); 1182 return err; 1183 } 1184 1185 1186 /* Common code used when first setting up, and when resuming. */ 1187 static int talk_to_blkback(struct xenbus_device *dev, 1188 struct blkfront_info *info) 1189 { 1190 const char *message = NULL; 1191 struct xenbus_transaction xbt; 1192 int err; 1193 1194 /* Create shared ring, alloc event channel. */ 1195 err = setup_blkring(dev, info); 1196 if (err) 1197 goto out; 1198 1199 again: 1200 err = xenbus_transaction_start(&xbt); 1201 if (err) { 1202 xenbus_dev_fatal(dev, err, "starting transaction"); 1203 goto destroy_blkring; 1204 } 1205 1206 err = xenbus_printf(xbt, dev->nodename, 1207 "ring-ref", "%u", info->ring_ref); 1208 if (err) { 1209 message = "writing ring-ref"; 1210 goto abort_transaction; 1211 } 1212 err = xenbus_printf(xbt, dev->nodename, 1213 "event-channel", "%u", info->evtchn); 1214 if (err) { 1215 message = "writing event-channel"; 1216 goto abort_transaction; 1217 } 1218 err = xenbus_printf(xbt, dev->nodename, "protocol", "%s", 1219 XEN_IO_PROTO_ABI_NATIVE); 1220 if (err) { 1221 message = "writing protocol"; 1222 goto abort_transaction; 1223 } 1224 err = xenbus_printf(xbt, dev->nodename, 1225 "feature-persistent", "%u", 1); 1226 if (err) 1227 dev_warn(&dev->dev, 1228 "writing persistent grants feature to xenbus"); 1229 1230 err = xenbus_transaction_end(xbt, 0); 1231 if (err) { 1232 if (err == -EAGAIN) 1233 goto again; 1234 xenbus_dev_fatal(dev, err, "completing transaction"); 1235 goto destroy_blkring; 1236 } 1237 1238 xenbus_switch_state(dev, XenbusStateInitialised); 1239 1240 return 0; 1241 1242 abort_transaction: 1243 xenbus_transaction_end(xbt, 1); 1244 if (message) 1245 xenbus_dev_fatal(dev, err, "%s", message); 1246 destroy_blkring: 1247 blkif_free(info, 0); 1248 out: 1249 return err; 1250 } 1251 1252 /** 1253 * Entry point to this code when a new device is created. Allocate the basic 1254 * structures and the ring buffer for communication with the backend, and 1255 * inform the backend of the appropriate details for those. Switch to 1256 * Initialised state. 1257 */ 1258 static int blkfront_probe(struct xenbus_device *dev, 1259 const struct xenbus_device_id *id) 1260 { 1261 int err, vdevice, i; 1262 struct blkfront_info *info; 1263 1264 /* FIXME: Use dynamic device id if this is not set. */ 1265 err = xenbus_scanf(XBT_NIL, dev->nodename, 1266 "virtual-device", "%i", &vdevice); 1267 if (err != 1) { 1268 /* go looking in the extended area instead */ 1269 err = xenbus_scanf(XBT_NIL, dev->nodename, "virtual-device-ext", 1270 "%i", &vdevice); 1271 if (err != 1) { 1272 xenbus_dev_fatal(dev, err, "reading virtual-device"); 1273 return err; 1274 } 1275 } 1276 1277 if (xen_hvm_domain()) { 1278 char *type; 1279 int len; 1280 /* no unplug has been done: do not hook devices != xen vbds */ 1281 if (xen_platform_pci_unplug & XEN_UNPLUG_UNNECESSARY) { 1282 int major; 1283 1284 if (!VDEV_IS_EXTENDED(vdevice)) 1285 major = BLKIF_MAJOR(vdevice); 1286 else 1287 major = XENVBD_MAJOR; 1288 1289 if (major != XENVBD_MAJOR) { 1290 printk(KERN_INFO 1291 "%s: HVM does not support vbd %d as xen block device\n", 1292 __FUNCTION__, vdevice); 1293 return -ENODEV; 1294 } 1295 } 1296 /* do not create a PV cdrom device if we are an HVM guest */ 1297 type = xenbus_read(XBT_NIL, dev->nodename, "device-type", &len); 1298 if (IS_ERR(type)) 1299 return -ENODEV; 1300 if (strncmp(type, "cdrom", 5) == 0) { 1301 kfree(type); 1302 return -ENODEV; 1303 } 1304 kfree(type); 1305 } 1306 info = kzalloc(sizeof(*info), GFP_KERNEL); 1307 if (!info) { 1308 xenbus_dev_fatal(dev, -ENOMEM, "allocating info structure"); 1309 return -ENOMEM; 1310 } 1311 1312 mutex_init(&info->mutex); 1313 spin_lock_init(&info->io_lock); 1314 info->xbdev = dev; 1315 info->vdevice = vdevice; 1316 INIT_LIST_HEAD(&info->persistent_gnts); 1317 info->persistent_gnts_c = 0; 1318 info->connected = BLKIF_STATE_DISCONNECTED; 1319 INIT_WORK(&info->work, blkif_restart_queue); 1320 1321 for (i = 0; i < BLK_RING_SIZE; i++) 1322 info->shadow[i].req.u.rw.id = i+1; 1323 info->shadow[BLK_RING_SIZE-1].req.u.rw.id = 0x0fffffff; 1324 1325 /* Front end dir is a number, which is used as the id. */ 1326 info->handle = simple_strtoul(strrchr(dev->nodename, '/')+1, NULL, 0); 1327 dev_set_drvdata(&dev->dev, info); 1328 1329 err = talk_to_blkback(dev, info); 1330 if (err) { 1331 kfree(info); 1332 dev_set_drvdata(&dev->dev, NULL); 1333 return err; 1334 } 1335 1336 return 0; 1337 } 1338 1339 /* 1340 * This is a clone of md_trim_bio, used to split a bio into smaller ones 1341 */ 1342 static void trim_bio(struct bio *bio, int offset, int size) 1343 { 1344 /* 'bio' is a cloned bio which we need to trim to match 1345 * the given offset and size. 1346 * This requires adjusting bi_sector, bi_size, and bi_io_vec 1347 */ 1348 int i; 1349 struct bio_vec *bvec; 1350 int sofar = 0; 1351 1352 size <<= 9; 1353 if (offset == 0 && size == bio->bi_size) 1354 return; 1355 1356 bio->bi_sector += offset; 1357 bio->bi_size = size; 1358 offset <<= 9; 1359 clear_bit(BIO_SEG_VALID, &bio->bi_flags); 1360 1361 while (bio->bi_idx < bio->bi_vcnt && 1362 bio->bi_io_vec[bio->bi_idx].bv_len <= offset) { 1363 /* remove this whole bio_vec */ 1364 offset -= bio->bi_io_vec[bio->bi_idx].bv_len; 1365 bio->bi_idx++; 1366 } 1367 if (bio->bi_idx < bio->bi_vcnt) { 1368 bio->bi_io_vec[bio->bi_idx].bv_offset += offset; 1369 bio->bi_io_vec[bio->bi_idx].bv_len -= offset; 1370 } 1371 /* avoid any complications with bi_idx being non-zero*/ 1372 if (bio->bi_idx) { 1373 memmove(bio->bi_io_vec, bio->bi_io_vec+bio->bi_idx, 1374 (bio->bi_vcnt - bio->bi_idx) * sizeof(struct bio_vec)); 1375 bio->bi_vcnt -= bio->bi_idx; 1376 bio->bi_idx = 0; 1377 } 1378 /* Make sure vcnt and last bv are not too big */ 1379 bio_for_each_segment(bvec, bio, i) { 1380 if (sofar + bvec->bv_len > size) 1381 bvec->bv_len = size - sofar; 1382 if (bvec->bv_len == 0) { 1383 bio->bi_vcnt = i; 1384 break; 1385 } 1386 sofar += bvec->bv_len; 1387 } 1388 } 1389 1390 static void split_bio_end(struct bio *bio, int error) 1391 { 1392 struct split_bio *split_bio = bio->bi_private; 1393 1394 if (error) 1395 split_bio->err = error; 1396 1397 if (atomic_dec_and_test(&split_bio->pending)) { 1398 split_bio->bio->bi_phys_segments = 0; 1399 bio_endio(split_bio->bio, split_bio->err); 1400 kfree(split_bio); 1401 } 1402 bio_put(bio); 1403 } 1404 1405 static int blkif_recover(struct blkfront_info *info) 1406 { 1407 int i; 1408 struct request *req, *n; 1409 struct blk_shadow *copy; 1410 int rc; 1411 struct bio *bio, *cloned_bio; 1412 struct bio_list bio_list, merge_bio; 1413 unsigned int segs, offset; 1414 int pending, size; 1415 struct split_bio *split_bio; 1416 struct list_head requests; 1417 1418 /* Stage 1: Make a safe copy of the shadow state. */ 1419 copy = kmemdup(info->shadow, sizeof(info->shadow), 1420 GFP_NOIO | __GFP_REPEAT | __GFP_HIGH); 1421 if (!copy) 1422 return -ENOMEM; 1423 1424 /* Stage 2: Set up free list. */ 1425 memset(&info->shadow, 0, sizeof(info->shadow)); 1426 for (i = 0; i < BLK_RING_SIZE; i++) 1427 info->shadow[i].req.u.rw.id = i+1; 1428 info->shadow_free = info->ring.req_prod_pvt; 1429 info->shadow[BLK_RING_SIZE-1].req.u.rw.id = 0x0fffffff; 1430 1431 rc = blkfront_setup_indirect(info); 1432 if (rc) { 1433 kfree(copy); 1434 return rc; 1435 } 1436 1437 segs = info->max_indirect_segments ? : BLKIF_MAX_SEGMENTS_PER_REQUEST; 1438 blk_queue_max_segments(info->rq, segs); 1439 bio_list_init(&bio_list); 1440 INIT_LIST_HEAD(&requests); 1441 for (i = 0; i < BLK_RING_SIZE; i++) { 1442 /* Not in use? */ 1443 if (!copy[i].request) 1444 continue; 1445 1446 /* 1447 * Get the bios in the request so we can re-queue them. 1448 */ 1449 if (copy[i].request->cmd_flags & 1450 (REQ_FLUSH | REQ_FUA | REQ_DISCARD | REQ_SECURE)) { 1451 /* 1452 * Flush operations don't contain bios, so 1453 * we need to requeue the whole request 1454 */ 1455 list_add(©[i].request->queuelist, &requests); 1456 continue; 1457 } 1458 merge_bio.head = copy[i].request->bio; 1459 merge_bio.tail = copy[i].request->biotail; 1460 bio_list_merge(&bio_list, &merge_bio); 1461 copy[i].request->bio = NULL; 1462 blk_put_request(copy[i].request); 1463 } 1464 1465 kfree(copy); 1466 1467 /* 1468 * Empty the queue, this is important because we might have 1469 * requests in the queue with more segments than what we 1470 * can handle now. 1471 */ 1472 spin_lock_irq(&info->io_lock); 1473 while ((req = blk_fetch_request(info->rq)) != NULL) { 1474 if (req->cmd_flags & 1475 (REQ_FLUSH | REQ_FUA | REQ_DISCARD | REQ_SECURE)) { 1476 list_add(&req->queuelist, &requests); 1477 continue; 1478 } 1479 merge_bio.head = req->bio; 1480 merge_bio.tail = req->biotail; 1481 bio_list_merge(&bio_list, &merge_bio); 1482 req->bio = NULL; 1483 if (req->cmd_flags & (REQ_FLUSH | REQ_FUA)) 1484 pr_alert("diskcache flush request found!\n"); 1485 __blk_put_request(info->rq, req); 1486 } 1487 spin_unlock_irq(&info->io_lock); 1488 1489 xenbus_switch_state(info->xbdev, XenbusStateConnected); 1490 1491 spin_lock_irq(&info->io_lock); 1492 1493 /* Now safe for us to use the shared ring */ 1494 info->connected = BLKIF_STATE_CONNECTED; 1495 1496 /* Kick any other new requests queued since we resumed */ 1497 kick_pending_request_queues(info); 1498 1499 list_for_each_entry_safe(req, n, &requests, queuelist) { 1500 /* Requeue pending requests (flush or discard) */ 1501 list_del_init(&req->queuelist); 1502 BUG_ON(req->nr_phys_segments > segs); 1503 blk_requeue_request(info->rq, req); 1504 } 1505 spin_unlock_irq(&info->io_lock); 1506 1507 while ((bio = bio_list_pop(&bio_list)) != NULL) { 1508 /* Traverse the list of pending bios and re-queue them */ 1509 if (bio_segments(bio) > segs) { 1510 /* 1511 * This bio has more segments than what we can 1512 * handle, we have to split it. 1513 */ 1514 pending = (bio_segments(bio) + segs - 1) / segs; 1515 split_bio = kzalloc(sizeof(*split_bio), GFP_NOIO); 1516 BUG_ON(split_bio == NULL); 1517 atomic_set(&split_bio->pending, pending); 1518 split_bio->bio = bio; 1519 for (i = 0; i < pending; i++) { 1520 offset = (i * segs * PAGE_SIZE) >> 9; 1521 size = min((unsigned int)(segs * PAGE_SIZE) >> 9, 1522 (unsigned int)(bio->bi_size >> 9) - offset); 1523 cloned_bio = bio_clone(bio, GFP_NOIO); 1524 BUG_ON(cloned_bio == NULL); 1525 trim_bio(cloned_bio, offset, size); 1526 cloned_bio->bi_private = split_bio; 1527 cloned_bio->bi_end_io = split_bio_end; 1528 submit_bio(cloned_bio->bi_rw, cloned_bio); 1529 } 1530 /* 1531 * Now we have to wait for all those smaller bios to 1532 * end, so we can also end the "parent" bio. 1533 */ 1534 continue; 1535 } 1536 /* We don't need to split this bio */ 1537 submit_bio(bio->bi_rw, bio); 1538 } 1539 1540 return 0; 1541 } 1542 1543 /** 1544 * We are reconnecting to the backend, due to a suspend/resume, or a backend 1545 * driver restart. We tear down our blkif structure and recreate it, but 1546 * leave the device-layer structures intact so that this is transparent to the 1547 * rest of the kernel. 1548 */ 1549 static int blkfront_resume(struct xenbus_device *dev) 1550 { 1551 struct blkfront_info *info = dev_get_drvdata(&dev->dev); 1552 int err; 1553 1554 dev_dbg(&dev->dev, "blkfront_resume: %s\n", dev->nodename); 1555 1556 blkif_free(info, info->connected == BLKIF_STATE_CONNECTED); 1557 1558 err = talk_to_blkback(dev, info); 1559 1560 /* 1561 * We have to wait for the backend to switch to 1562 * connected state, since we want to read which 1563 * features it supports. 1564 */ 1565 1566 return err; 1567 } 1568 1569 static void 1570 blkfront_closing(struct blkfront_info *info) 1571 { 1572 struct xenbus_device *xbdev = info->xbdev; 1573 struct block_device *bdev = NULL; 1574 1575 mutex_lock(&info->mutex); 1576 1577 if (xbdev->state == XenbusStateClosing) { 1578 mutex_unlock(&info->mutex); 1579 return; 1580 } 1581 1582 if (info->gd) 1583 bdev = bdget_disk(info->gd, 0); 1584 1585 mutex_unlock(&info->mutex); 1586 1587 if (!bdev) { 1588 xenbus_frontend_closed(xbdev); 1589 return; 1590 } 1591 1592 mutex_lock(&bdev->bd_mutex); 1593 1594 if (bdev->bd_openers) { 1595 xenbus_dev_error(xbdev, -EBUSY, 1596 "Device in use; refusing to close"); 1597 xenbus_switch_state(xbdev, XenbusStateClosing); 1598 } else { 1599 xlvbd_release_gendisk(info); 1600 xenbus_frontend_closed(xbdev); 1601 } 1602 1603 mutex_unlock(&bdev->bd_mutex); 1604 bdput(bdev); 1605 } 1606 1607 static void blkfront_setup_discard(struct blkfront_info *info) 1608 { 1609 int err; 1610 char *type; 1611 unsigned int discard_granularity; 1612 unsigned int discard_alignment; 1613 unsigned int discard_secure; 1614 1615 type = xenbus_read(XBT_NIL, info->xbdev->otherend, "type", NULL); 1616 if (IS_ERR(type)) 1617 return; 1618 1619 info->feature_secdiscard = 0; 1620 if (strncmp(type, "phy", 3) == 0) { 1621 err = xenbus_gather(XBT_NIL, info->xbdev->otherend, 1622 "discard-granularity", "%u", &discard_granularity, 1623 "discard-alignment", "%u", &discard_alignment, 1624 NULL); 1625 if (!err) { 1626 info->feature_discard = 1; 1627 info->discard_granularity = discard_granularity; 1628 info->discard_alignment = discard_alignment; 1629 } 1630 err = xenbus_gather(XBT_NIL, info->xbdev->otherend, 1631 "discard-secure", "%d", &discard_secure, 1632 NULL); 1633 if (!err) 1634 info->feature_secdiscard = discard_secure; 1635 1636 } else if (strncmp(type, "file", 4) == 0) 1637 info->feature_discard = 1; 1638 1639 kfree(type); 1640 } 1641 1642 static int blkfront_setup_indirect(struct blkfront_info *info) 1643 { 1644 unsigned int indirect_segments, segs; 1645 int err, i; 1646 1647 err = xenbus_gather(XBT_NIL, info->xbdev->otherend, 1648 "feature-max-indirect-segments", "%u", &indirect_segments, 1649 NULL); 1650 if (err) { 1651 info->max_indirect_segments = 0; 1652 segs = BLKIF_MAX_SEGMENTS_PER_REQUEST; 1653 } else { 1654 info->max_indirect_segments = min(indirect_segments, 1655 xen_blkif_max_segments); 1656 segs = info->max_indirect_segments; 1657 } 1658 1659 err = fill_grant_buffer(info, (segs + INDIRECT_GREFS(segs)) * BLK_RING_SIZE); 1660 if (err) 1661 goto out_of_memory; 1662 1663 for (i = 0; i < BLK_RING_SIZE; i++) { 1664 info->shadow[i].grants_used = kzalloc( 1665 sizeof(info->shadow[i].grants_used[0]) * segs, 1666 GFP_NOIO); 1667 info->shadow[i].sg = kzalloc(sizeof(info->shadow[i].sg[0]) * segs, GFP_NOIO); 1668 if (info->max_indirect_segments) 1669 info->shadow[i].indirect_grants = kzalloc( 1670 sizeof(info->shadow[i].indirect_grants[0]) * 1671 INDIRECT_GREFS(segs), 1672 GFP_NOIO); 1673 if ((info->shadow[i].grants_used == NULL) || 1674 (info->shadow[i].sg == NULL) || 1675 (info->max_indirect_segments && 1676 (info->shadow[i].indirect_grants == NULL))) 1677 goto out_of_memory; 1678 sg_init_table(info->shadow[i].sg, segs); 1679 } 1680 1681 1682 return 0; 1683 1684 out_of_memory: 1685 for (i = 0; i < BLK_RING_SIZE; i++) { 1686 kfree(info->shadow[i].grants_used); 1687 info->shadow[i].grants_used = NULL; 1688 kfree(info->shadow[i].sg); 1689 info->shadow[i].sg = NULL; 1690 kfree(info->shadow[i].indirect_grants); 1691 info->shadow[i].indirect_grants = NULL; 1692 } 1693 return -ENOMEM; 1694 } 1695 1696 /* 1697 * Invoked when the backend is finally 'ready' (and has told produced 1698 * the details about the physical device - #sectors, size, etc). 1699 */ 1700 static void blkfront_connect(struct blkfront_info *info) 1701 { 1702 unsigned long long sectors; 1703 unsigned long sector_size; 1704 unsigned int physical_sector_size; 1705 unsigned int binfo; 1706 int err; 1707 int barrier, flush, discard, persistent; 1708 1709 switch (info->connected) { 1710 case BLKIF_STATE_CONNECTED: 1711 /* 1712 * Potentially, the back-end may be signalling 1713 * a capacity change; update the capacity. 1714 */ 1715 err = xenbus_scanf(XBT_NIL, info->xbdev->otherend, 1716 "sectors", "%Lu", §ors); 1717 if (XENBUS_EXIST_ERR(err)) 1718 return; 1719 printk(KERN_INFO "Setting capacity to %Lu\n", 1720 sectors); 1721 set_capacity(info->gd, sectors); 1722 revalidate_disk(info->gd); 1723 1724 return; 1725 case BLKIF_STATE_SUSPENDED: 1726 /* 1727 * If we are recovering from suspension, we need to wait 1728 * for the backend to announce it's features before 1729 * reconnecting, at least we need to know if the backend 1730 * supports indirect descriptors, and how many. 1731 */ 1732 blkif_recover(info); 1733 return; 1734 1735 default: 1736 break; 1737 } 1738 1739 dev_dbg(&info->xbdev->dev, "%s:%s.\n", 1740 __func__, info->xbdev->otherend); 1741 1742 err = xenbus_gather(XBT_NIL, info->xbdev->otherend, 1743 "sectors", "%llu", §ors, 1744 "info", "%u", &binfo, 1745 "sector-size", "%lu", §or_size, 1746 NULL); 1747 if (err) { 1748 xenbus_dev_fatal(info->xbdev, err, 1749 "reading backend fields at %s", 1750 info->xbdev->otherend); 1751 return; 1752 } 1753 1754 /* 1755 * physcial-sector-size is a newer field, so old backends may not 1756 * provide this. Assume physical sector size to be the same as 1757 * sector_size in that case. 1758 */ 1759 err = xenbus_scanf(XBT_NIL, info->xbdev->otherend, 1760 "physical-sector-size", "%u", &physical_sector_size); 1761 if (err != 1) 1762 physical_sector_size = sector_size; 1763 1764 info->feature_flush = 0; 1765 info->flush_op = 0; 1766 1767 err = xenbus_gather(XBT_NIL, info->xbdev->otherend, 1768 "feature-barrier", "%d", &barrier, 1769 NULL); 1770 1771 /* 1772 * If there's no "feature-barrier" defined, then it means 1773 * we're dealing with a very old backend which writes 1774 * synchronously; nothing to do. 1775 * 1776 * If there are barriers, then we use flush. 1777 */ 1778 if (!err && barrier) { 1779 info->feature_flush = REQ_FLUSH | REQ_FUA; 1780 info->flush_op = BLKIF_OP_WRITE_BARRIER; 1781 } 1782 /* 1783 * And if there is "feature-flush-cache" use that above 1784 * barriers. 1785 */ 1786 err = xenbus_gather(XBT_NIL, info->xbdev->otherend, 1787 "feature-flush-cache", "%d", &flush, 1788 NULL); 1789 1790 if (!err && flush) { 1791 info->feature_flush = REQ_FLUSH; 1792 info->flush_op = BLKIF_OP_FLUSH_DISKCACHE; 1793 } 1794 1795 err = xenbus_gather(XBT_NIL, info->xbdev->otherend, 1796 "feature-discard", "%d", &discard, 1797 NULL); 1798 1799 if (!err && discard) 1800 blkfront_setup_discard(info); 1801 1802 err = xenbus_gather(XBT_NIL, info->xbdev->otherend, 1803 "feature-persistent", "%u", &persistent, 1804 NULL); 1805 if (err) 1806 info->feature_persistent = 0; 1807 else 1808 info->feature_persistent = persistent; 1809 1810 err = blkfront_setup_indirect(info); 1811 if (err) { 1812 xenbus_dev_fatal(info->xbdev, err, "setup_indirect at %s", 1813 info->xbdev->otherend); 1814 return; 1815 } 1816 1817 err = xlvbd_alloc_gendisk(sectors, info, binfo, sector_size, 1818 physical_sector_size); 1819 if (err) { 1820 xenbus_dev_fatal(info->xbdev, err, "xlvbd_add at %s", 1821 info->xbdev->otherend); 1822 return; 1823 } 1824 1825 xenbus_switch_state(info->xbdev, XenbusStateConnected); 1826 1827 /* Kick pending requests. */ 1828 spin_lock_irq(&info->io_lock); 1829 info->connected = BLKIF_STATE_CONNECTED; 1830 kick_pending_request_queues(info); 1831 spin_unlock_irq(&info->io_lock); 1832 1833 add_disk(info->gd); 1834 1835 info->is_ready = 1; 1836 } 1837 1838 /** 1839 * Callback received when the backend's state changes. 1840 */ 1841 static void blkback_changed(struct xenbus_device *dev, 1842 enum xenbus_state backend_state) 1843 { 1844 struct blkfront_info *info = dev_get_drvdata(&dev->dev); 1845 1846 dev_dbg(&dev->dev, "blkfront:blkback_changed to state %d.\n", backend_state); 1847 1848 switch (backend_state) { 1849 case XenbusStateInitialising: 1850 case XenbusStateInitWait: 1851 case XenbusStateInitialised: 1852 case XenbusStateReconfiguring: 1853 case XenbusStateReconfigured: 1854 case XenbusStateUnknown: 1855 case XenbusStateClosed: 1856 break; 1857 1858 case XenbusStateConnected: 1859 blkfront_connect(info); 1860 break; 1861 1862 case XenbusStateClosing: 1863 blkfront_closing(info); 1864 break; 1865 } 1866 } 1867 1868 static int blkfront_remove(struct xenbus_device *xbdev) 1869 { 1870 struct blkfront_info *info = dev_get_drvdata(&xbdev->dev); 1871 struct block_device *bdev = NULL; 1872 struct gendisk *disk; 1873 1874 dev_dbg(&xbdev->dev, "%s removed", xbdev->nodename); 1875 1876 blkif_free(info, 0); 1877 1878 mutex_lock(&info->mutex); 1879 1880 disk = info->gd; 1881 if (disk) 1882 bdev = bdget_disk(disk, 0); 1883 1884 info->xbdev = NULL; 1885 mutex_unlock(&info->mutex); 1886 1887 if (!bdev) { 1888 kfree(info); 1889 return 0; 1890 } 1891 1892 /* 1893 * The xbdev was removed before we reached the Closed 1894 * state. See if it's safe to remove the disk. If the bdev 1895 * isn't closed yet, we let release take care of it. 1896 */ 1897 1898 mutex_lock(&bdev->bd_mutex); 1899 info = disk->private_data; 1900 1901 dev_warn(disk_to_dev(disk), 1902 "%s was hot-unplugged, %d stale handles\n", 1903 xbdev->nodename, bdev->bd_openers); 1904 1905 if (info && !bdev->bd_openers) { 1906 xlvbd_release_gendisk(info); 1907 disk->private_data = NULL; 1908 kfree(info); 1909 } 1910 1911 mutex_unlock(&bdev->bd_mutex); 1912 bdput(bdev); 1913 1914 return 0; 1915 } 1916 1917 static int blkfront_is_ready(struct xenbus_device *dev) 1918 { 1919 struct blkfront_info *info = dev_get_drvdata(&dev->dev); 1920 1921 return info->is_ready && info->xbdev; 1922 } 1923 1924 static int blkif_open(struct block_device *bdev, fmode_t mode) 1925 { 1926 struct gendisk *disk = bdev->bd_disk; 1927 struct blkfront_info *info; 1928 int err = 0; 1929 1930 mutex_lock(&blkfront_mutex); 1931 1932 info = disk->private_data; 1933 if (!info) { 1934 /* xbdev gone */ 1935 err = -ERESTARTSYS; 1936 goto out; 1937 } 1938 1939 mutex_lock(&info->mutex); 1940 1941 if (!info->gd) 1942 /* xbdev is closed */ 1943 err = -ERESTARTSYS; 1944 1945 mutex_unlock(&info->mutex); 1946 1947 out: 1948 mutex_unlock(&blkfront_mutex); 1949 return err; 1950 } 1951 1952 static void blkif_release(struct gendisk *disk, fmode_t mode) 1953 { 1954 struct blkfront_info *info = disk->private_data; 1955 struct block_device *bdev; 1956 struct xenbus_device *xbdev; 1957 1958 mutex_lock(&blkfront_mutex); 1959 1960 bdev = bdget_disk(disk, 0); 1961 1962 if (bdev->bd_openers) 1963 goto out; 1964 1965 /* 1966 * Check if we have been instructed to close. We will have 1967 * deferred this request, because the bdev was still open. 1968 */ 1969 1970 mutex_lock(&info->mutex); 1971 xbdev = info->xbdev; 1972 1973 if (xbdev && xbdev->state == XenbusStateClosing) { 1974 /* pending switch to state closed */ 1975 dev_info(disk_to_dev(bdev->bd_disk), "releasing disk\n"); 1976 xlvbd_release_gendisk(info); 1977 xenbus_frontend_closed(info->xbdev); 1978 } 1979 1980 mutex_unlock(&info->mutex); 1981 1982 if (!xbdev) { 1983 /* sudden device removal */ 1984 dev_info(disk_to_dev(bdev->bd_disk), "releasing disk\n"); 1985 xlvbd_release_gendisk(info); 1986 disk->private_data = NULL; 1987 kfree(info); 1988 } 1989 1990 out: 1991 bdput(bdev); 1992 mutex_unlock(&blkfront_mutex); 1993 } 1994 1995 static const struct block_device_operations xlvbd_block_fops = 1996 { 1997 .owner = THIS_MODULE, 1998 .open = blkif_open, 1999 .release = blkif_release, 2000 .getgeo = blkif_getgeo, 2001 .ioctl = blkif_ioctl, 2002 }; 2003 2004 2005 static const struct xenbus_device_id blkfront_ids[] = { 2006 { "vbd" }, 2007 { "" } 2008 }; 2009 2010 static DEFINE_XENBUS_DRIVER(blkfront, , 2011 .probe = blkfront_probe, 2012 .remove = blkfront_remove, 2013 .resume = blkfront_resume, 2014 .otherend_changed = blkback_changed, 2015 .is_ready = blkfront_is_ready, 2016 ); 2017 2018 static int __init xlblk_init(void) 2019 { 2020 int ret; 2021 2022 if (!xen_domain()) 2023 return -ENODEV; 2024 2025 if (xen_hvm_domain() && !xen_platform_pci_unplug) 2026 return -ENODEV; 2027 2028 if (register_blkdev(XENVBD_MAJOR, DEV_NAME)) { 2029 printk(KERN_WARNING "xen_blk: can't get major %d with name %s\n", 2030 XENVBD_MAJOR, DEV_NAME); 2031 return -ENODEV; 2032 } 2033 2034 ret = xenbus_register_frontend(&blkfront_driver); 2035 if (ret) { 2036 unregister_blkdev(XENVBD_MAJOR, DEV_NAME); 2037 return ret; 2038 } 2039 2040 return 0; 2041 } 2042 module_init(xlblk_init); 2043 2044 2045 static void __exit xlblk_exit(void) 2046 { 2047 xenbus_unregister_driver(&blkfront_driver); 2048 unregister_blkdev(XENVBD_MAJOR, DEV_NAME); 2049 kfree(minors); 2050 } 2051 module_exit(xlblk_exit); 2052 2053 MODULE_DESCRIPTION("Xen virtual block device frontend"); 2054 MODULE_LICENSE("GPL"); 2055 MODULE_ALIAS_BLOCKDEV_MAJOR(XENVBD_MAJOR); 2056 MODULE_ALIAS("xen:vbd"); 2057 MODULE_ALIAS("xenblk"); 2058