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 47 #include <xen/xen.h> 48 #include <xen/xenbus.h> 49 #include <xen/grant_table.h> 50 #include <xen/events.h> 51 #include <xen/page.h> 52 #include <xen/platform_pci.h> 53 54 #include <xen/interface/grant_table.h> 55 #include <xen/interface/io/blkif.h> 56 #include <xen/interface/io/protocols.h> 57 58 #include <asm/xen/hypervisor.h> 59 60 enum blkif_state { 61 BLKIF_STATE_DISCONNECTED, 62 BLKIF_STATE_CONNECTED, 63 BLKIF_STATE_SUSPENDED, 64 }; 65 66 struct blk_shadow { 67 struct blkif_request req; 68 struct request *request; 69 unsigned long frame[BLKIF_MAX_SEGMENTS_PER_REQUEST]; 70 }; 71 72 static DEFINE_MUTEX(blkfront_mutex); 73 static const struct block_device_operations xlvbd_block_fops; 74 75 #define BLK_RING_SIZE __CONST_RING_SIZE(blkif, PAGE_SIZE) 76 77 /* 78 * We have one of these per vbd, whether ide, scsi or 'other'. They 79 * hang in private_data off the gendisk structure. We may end up 80 * putting all kinds of interesting stuff here :-) 81 */ 82 struct blkfront_info 83 { 84 struct mutex mutex; 85 struct xenbus_device *xbdev; 86 struct gendisk *gd; 87 int vdevice; 88 blkif_vdev_t handle; 89 enum blkif_state connected; 90 int ring_ref; 91 struct blkif_front_ring ring; 92 struct scatterlist sg[BLKIF_MAX_SEGMENTS_PER_REQUEST]; 93 unsigned int evtchn, irq; 94 struct request_queue *rq; 95 struct work_struct work; 96 struct gnttab_free_callback callback; 97 struct blk_shadow shadow[BLK_RING_SIZE]; 98 unsigned long shadow_free; 99 unsigned int feature_flush; 100 unsigned int flush_op; 101 unsigned int feature_discard; 102 unsigned int discard_granularity; 103 unsigned int discard_alignment; 104 int is_ready; 105 }; 106 107 static DEFINE_SPINLOCK(blkif_io_lock); 108 109 static unsigned int nr_minors; 110 static unsigned long *minors; 111 static DEFINE_SPINLOCK(minor_lock); 112 113 #define MAXIMUM_OUTSTANDING_BLOCK_REQS \ 114 (BLKIF_MAX_SEGMENTS_PER_REQUEST * BLK_RING_SIZE) 115 #define GRANT_INVALID_REF 0 116 117 #define PARTS_PER_DISK 16 118 #define PARTS_PER_EXT_DISK 256 119 120 #define BLKIF_MAJOR(dev) ((dev)>>8) 121 #define BLKIF_MINOR(dev) ((dev) & 0xff) 122 123 #define EXT_SHIFT 28 124 #define EXTENDED (1<<EXT_SHIFT) 125 #define VDEV_IS_EXTENDED(dev) ((dev)&(EXTENDED)) 126 #define BLKIF_MINOR_EXT(dev) ((dev)&(~EXTENDED)) 127 #define EMULATED_HD_DISK_MINOR_OFFSET (0) 128 #define EMULATED_HD_DISK_NAME_OFFSET (EMULATED_HD_DISK_MINOR_OFFSET / 256) 129 #define EMULATED_SD_DISK_MINOR_OFFSET (0) 130 #define EMULATED_SD_DISK_NAME_OFFSET (EMULATED_SD_DISK_MINOR_OFFSET / 256) 131 132 #define DEV_NAME "xvd" /* name in /dev */ 133 134 static int get_id_from_freelist(struct blkfront_info *info) 135 { 136 unsigned long free = info->shadow_free; 137 BUG_ON(free >= BLK_RING_SIZE); 138 info->shadow_free = info->shadow[free].req.id; 139 info->shadow[free].req.id = 0x0fffffee; /* debug */ 140 return free; 141 } 142 143 static void add_id_to_freelist(struct blkfront_info *info, 144 unsigned long id) 145 { 146 info->shadow[id].req.id = info->shadow_free; 147 info->shadow[id].request = NULL; 148 info->shadow_free = id; 149 } 150 151 static int xlbd_reserve_minors(unsigned int minor, unsigned int nr) 152 { 153 unsigned int end = minor + nr; 154 int rc; 155 156 if (end > nr_minors) { 157 unsigned long *bitmap, *old; 158 159 bitmap = kzalloc(BITS_TO_LONGS(end) * sizeof(*bitmap), 160 GFP_KERNEL); 161 if (bitmap == NULL) 162 return -ENOMEM; 163 164 spin_lock(&minor_lock); 165 if (end > nr_minors) { 166 old = minors; 167 memcpy(bitmap, minors, 168 BITS_TO_LONGS(nr_minors) * sizeof(*bitmap)); 169 minors = bitmap; 170 nr_minors = BITS_TO_LONGS(end) * BITS_PER_LONG; 171 } else 172 old = bitmap; 173 spin_unlock(&minor_lock); 174 kfree(old); 175 } 176 177 spin_lock(&minor_lock); 178 if (find_next_bit(minors, end, minor) >= end) { 179 for (; minor < end; ++minor) 180 __set_bit(minor, minors); 181 rc = 0; 182 } else 183 rc = -EBUSY; 184 spin_unlock(&minor_lock); 185 186 return rc; 187 } 188 189 static void xlbd_release_minors(unsigned int minor, unsigned int nr) 190 { 191 unsigned int end = minor + nr; 192 193 BUG_ON(end > nr_minors); 194 spin_lock(&minor_lock); 195 for (; minor < end; ++minor) 196 __clear_bit(minor, minors); 197 spin_unlock(&minor_lock); 198 } 199 200 static void blkif_restart_queue_callback(void *arg) 201 { 202 struct blkfront_info *info = (struct blkfront_info *)arg; 203 schedule_work(&info->work); 204 } 205 206 static int blkif_getgeo(struct block_device *bd, struct hd_geometry *hg) 207 { 208 /* We don't have real geometry info, but let's at least return 209 values consistent with the size of the device */ 210 sector_t nsect = get_capacity(bd->bd_disk); 211 sector_t cylinders = nsect; 212 213 hg->heads = 0xff; 214 hg->sectors = 0x3f; 215 sector_div(cylinders, hg->heads * hg->sectors); 216 hg->cylinders = cylinders; 217 if ((sector_t)(hg->cylinders + 1) * hg->heads * hg->sectors < nsect) 218 hg->cylinders = 0xffff; 219 return 0; 220 } 221 222 static int blkif_ioctl(struct block_device *bdev, fmode_t mode, 223 unsigned command, unsigned long argument) 224 { 225 struct blkfront_info *info = bdev->bd_disk->private_data; 226 int i; 227 228 dev_dbg(&info->xbdev->dev, "command: 0x%x, argument: 0x%lx\n", 229 command, (long)argument); 230 231 switch (command) { 232 case CDROMMULTISESSION: 233 dev_dbg(&info->xbdev->dev, "FIXME: support multisession CDs later\n"); 234 for (i = 0; i < sizeof(struct cdrom_multisession); i++) 235 if (put_user(0, (char __user *)(argument + i))) 236 return -EFAULT; 237 return 0; 238 239 case CDROM_GET_CAPABILITY: { 240 struct gendisk *gd = info->gd; 241 if (gd->flags & GENHD_FL_CD) 242 return 0; 243 return -EINVAL; 244 } 245 246 default: 247 /*printk(KERN_ALERT "ioctl %08x not supported by Xen blkdev\n", 248 command);*/ 249 return -EINVAL; /* same return as native Linux */ 250 } 251 252 return 0; 253 } 254 255 /* 256 * Generate a Xen blkfront IO request from a blk layer request. Reads 257 * and writes are handled as expected. 258 * 259 * @req: a request struct 260 */ 261 static int blkif_queue_request(struct request *req) 262 { 263 struct blkfront_info *info = req->rq_disk->private_data; 264 unsigned long buffer_mfn; 265 struct blkif_request *ring_req; 266 unsigned long id; 267 unsigned int fsect, lsect; 268 int i, ref; 269 grant_ref_t gref_head; 270 struct scatterlist *sg; 271 272 if (unlikely(info->connected != BLKIF_STATE_CONNECTED)) 273 return 1; 274 275 if (gnttab_alloc_grant_references( 276 BLKIF_MAX_SEGMENTS_PER_REQUEST, &gref_head) < 0) { 277 gnttab_request_free_callback( 278 &info->callback, 279 blkif_restart_queue_callback, 280 info, 281 BLKIF_MAX_SEGMENTS_PER_REQUEST); 282 return 1; 283 } 284 285 /* Fill out a communications ring structure. */ 286 ring_req = RING_GET_REQUEST(&info->ring, info->ring.req_prod_pvt); 287 id = get_id_from_freelist(info); 288 info->shadow[id].request = req; 289 290 ring_req->id = id; 291 ring_req->u.rw.sector_number = (blkif_sector_t)blk_rq_pos(req); 292 ring_req->handle = info->handle; 293 294 ring_req->operation = rq_data_dir(req) ? 295 BLKIF_OP_WRITE : BLKIF_OP_READ; 296 297 if (req->cmd_flags & (REQ_FLUSH | REQ_FUA)) { 298 /* 299 * Ideally we can do an unordered flush-to-disk. In case the 300 * backend onlysupports barriers, use that. A barrier request 301 * a superset of FUA, so we can implement it the same 302 * way. (It's also a FLUSH+FUA, since it is 303 * guaranteed ordered WRT previous writes.) 304 */ 305 ring_req->operation = info->flush_op; 306 } 307 308 if (unlikely(req->cmd_flags & REQ_DISCARD)) { 309 /* id, sector_number and handle are set above. */ 310 ring_req->operation = BLKIF_OP_DISCARD; 311 ring_req->nr_segments = 0; 312 ring_req->u.discard.nr_sectors = blk_rq_sectors(req); 313 } else { 314 ring_req->nr_segments = blk_rq_map_sg(req->q, req, info->sg); 315 BUG_ON(ring_req->nr_segments > BLKIF_MAX_SEGMENTS_PER_REQUEST); 316 317 for_each_sg(info->sg, sg, ring_req->nr_segments, i) { 318 buffer_mfn = pfn_to_mfn(page_to_pfn(sg_page(sg))); 319 fsect = sg->offset >> 9; 320 lsect = fsect + (sg->length >> 9) - 1; 321 /* install a grant reference. */ 322 ref = gnttab_claim_grant_reference(&gref_head); 323 BUG_ON(ref == -ENOSPC); 324 325 gnttab_grant_foreign_access_ref( 326 ref, 327 info->xbdev->otherend_id, 328 buffer_mfn, 329 rq_data_dir(req)); 330 331 info->shadow[id].frame[i] = mfn_to_pfn(buffer_mfn); 332 ring_req->u.rw.seg[i] = 333 (struct blkif_request_segment) { 334 .gref = ref, 335 .first_sect = fsect, 336 .last_sect = lsect }; 337 } 338 } 339 340 info->ring.req_prod_pvt++; 341 342 /* Keep a private copy so we can reissue requests when recovering. */ 343 info->shadow[id].req = *ring_req; 344 345 gnttab_free_grant_references(gref_head); 346 347 return 0; 348 } 349 350 351 static inline void flush_requests(struct blkfront_info *info) 352 { 353 int notify; 354 355 RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&info->ring, notify); 356 357 if (notify) 358 notify_remote_via_irq(info->irq); 359 } 360 361 /* 362 * do_blkif_request 363 * read a block; request is in a request queue 364 */ 365 static void do_blkif_request(struct request_queue *rq) 366 { 367 struct blkfront_info *info = NULL; 368 struct request *req; 369 int queued; 370 371 pr_debug("Entered do_blkif_request\n"); 372 373 queued = 0; 374 375 while ((req = blk_peek_request(rq)) != NULL) { 376 info = req->rq_disk->private_data; 377 378 if (RING_FULL(&info->ring)) 379 goto wait; 380 381 blk_start_request(req); 382 383 if ((req->cmd_type != REQ_TYPE_FS) || 384 ((req->cmd_flags & (REQ_FLUSH | REQ_FUA)) && 385 !info->flush_op)) { 386 __blk_end_request_all(req, -EIO); 387 continue; 388 } 389 390 pr_debug("do_blk_req %p: cmd %p, sec %lx, " 391 "(%u/%u) buffer:%p [%s]\n", 392 req, req->cmd, (unsigned long)blk_rq_pos(req), 393 blk_rq_cur_sectors(req), blk_rq_sectors(req), 394 req->buffer, rq_data_dir(req) ? "write" : "read"); 395 396 if (blkif_queue_request(req)) { 397 blk_requeue_request(rq, req); 398 wait: 399 /* Avoid pointless unplugs. */ 400 blk_stop_queue(rq); 401 break; 402 } 403 404 queued++; 405 } 406 407 if (queued != 0) 408 flush_requests(info); 409 } 410 411 static int xlvbd_init_blk_queue(struct gendisk *gd, u16 sector_size) 412 { 413 struct request_queue *rq; 414 struct blkfront_info *info = gd->private_data; 415 416 rq = blk_init_queue(do_blkif_request, &blkif_io_lock); 417 if (rq == NULL) 418 return -1; 419 420 queue_flag_set_unlocked(QUEUE_FLAG_VIRT, rq); 421 422 if (info->feature_discard) { 423 queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, rq); 424 blk_queue_max_discard_sectors(rq, get_capacity(gd)); 425 rq->limits.discard_granularity = info->discard_granularity; 426 rq->limits.discard_alignment = info->discard_alignment; 427 } 428 429 /* Hard sector size and max sectors impersonate the equiv. hardware. */ 430 blk_queue_logical_block_size(rq, sector_size); 431 blk_queue_max_hw_sectors(rq, 512); 432 433 /* Each segment in a request is up to an aligned page in size. */ 434 blk_queue_segment_boundary(rq, PAGE_SIZE - 1); 435 blk_queue_max_segment_size(rq, PAGE_SIZE); 436 437 /* Ensure a merged request will fit in a single I/O ring slot. */ 438 blk_queue_max_segments(rq, BLKIF_MAX_SEGMENTS_PER_REQUEST); 439 440 /* Make sure buffer addresses are sector-aligned. */ 441 blk_queue_dma_alignment(rq, 511); 442 443 /* Make sure we don't use bounce buffers. */ 444 blk_queue_bounce_limit(rq, BLK_BOUNCE_ANY); 445 446 gd->queue = rq; 447 448 return 0; 449 } 450 451 452 static void xlvbd_flush(struct blkfront_info *info) 453 { 454 blk_queue_flush(info->rq, info->feature_flush); 455 printk(KERN_INFO "blkfront: %s: %s: %s\n", 456 info->gd->disk_name, 457 info->flush_op == BLKIF_OP_WRITE_BARRIER ? 458 "barrier" : (info->flush_op == BLKIF_OP_FLUSH_DISKCACHE ? 459 "flush diskcache" : "barrier or flush"), 460 info->feature_flush ? "enabled" : "disabled"); 461 } 462 463 static int xen_translate_vdev(int vdevice, int *minor, unsigned int *offset) 464 { 465 int major; 466 major = BLKIF_MAJOR(vdevice); 467 *minor = BLKIF_MINOR(vdevice); 468 switch (major) { 469 case XEN_IDE0_MAJOR: 470 *offset = (*minor / 64) + EMULATED_HD_DISK_NAME_OFFSET; 471 *minor = ((*minor / 64) * PARTS_PER_DISK) + 472 EMULATED_HD_DISK_MINOR_OFFSET; 473 break; 474 case XEN_IDE1_MAJOR: 475 *offset = (*minor / 64) + 2 + EMULATED_HD_DISK_NAME_OFFSET; 476 *minor = (((*minor / 64) + 2) * PARTS_PER_DISK) + 477 EMULATED_HD_DISK_MINOR_OFFSET; 478 break; 479 case XEN_SCSI_DISK0_MAJOR: 480 *offset = (*minor / PARTS_PER_DISK) + EMULATED_SD_DISK_NAME_OFFSET; 481 *minor = *minor + EMULATED_SD_DISK_MINOR_OFFSET; 482 break; 483 case XEN_SCSI_DISK1_MAJOR: 484 case XEN_SCSI_DISK2_MAJOR: 485 case XEN_SCSI_DISK3_MAJOR: 486 case XEN_SCSI_DISK4_MAJOR: 487 case XEN_SCSI_DISK5_MAJOR: 488 case XEN_SCSI_DISK6_MAJOR: 489 case XEN_SCSI_DISK7_MAJOR: 490 *offset = (*minor / PARTS_PER_DISK) + 491 ((major - XEN_SCSI_DISK1_MAJOR + 1) * 16) + 492 EMULATED_SD_DISK_NAME_OFFSET; 493 *minor = *minor + 494 ((major - XEN_SCSI_DISK1_MAJOR + 1) * 16 * PARTS_PER_DISK) + 495 EMULATED_SD_DISK_MINOR_OFFSET; 496 break; 497 case XEN_SCSI_DISK8_MAJOR: 498 case XEN_SCSI_DISK9_MAJOR: 499 case XEN_SCSI_DISK10_MAJOR: 500 case XEN_SCSI_DISK11_MAJOR: 501 case XEN_SCSI_DISK12_MAJOR: 502 case XEN_SCSI_DISK13_MAJOR: 503 case XEN_SCSI_DISK14_MAJOR: 504 case XEN_SCSI_DISK15_MAJOR: 505 *offset = (*minor / PARTS_PER_DISK) + 506 ((major - XEN_SCSI_DISK8_MAJOR + 8) * 16) + 507 EMULATED_SD_DISK_NAME_OFFSET; 508 *minor = *minor + 509 ((major - XEN_SCSI_DISK8_MAJOR + 8) * 16 * PARTS_PER_DISK) + 510 EMULATED_SD_DISK_MINOR_OFFSET; 511 break; 512 case XENVBD_MAJOR: 513 *offset = *minor / PARTS_PER_DISK; 514 break; 515 default: 516 printk(KERN_WARNING "blkfront: your disk configuration is " 517 "incorrect, please use an xvd device instead\n"); 518 return -ENODEV; 519 } 520 return 0; 521 } 522 523 static int xlvbd_alloc_gendisk(blkif_sector_t capacity, 524 struct blkfront_info *info, 525 u16 vdisk_info, u16 sector_size) 526 { 527 struct gendisk *gd; 528 int nr_minors = 1; 529 int err; 530 unsigned int offset; 531 int minor; 532 int nr_parts; 533 534 BUG_ON(info->gd != NULL); 535 BUG_ON(info->rq != NULL); 536 537 if ((info->vdevice>>EXT_SHIFT) > 1) { 538 /* this is above the extended range; something is wrong */ 539 printk(KERN_WARNING "blkfront: vdevice 0x%x is above the extended range; ignoring\n", info->vdevice); 540 return -ENODEV; 541 } 542 543 if (!VDEV_IS_EXTENDED(info->vdevice)) { 544 err = xen_translate_vdev(info->vdevice, &minor, &offset); 545 if (err) 546 return err; 547 nr_parts = PARTS_PER_DISK; 548 } else { 549 minor = BLKIF_MINOR_EXT(info->vdevice); 550 nr_parts = PARTS_PER_EXT_DISK; 551 offset = minor / nr_parts; 552 if (xen_hvm_domain() && offset < EMULATED_HD_DISK_NAME_OFFSET + 4) 553 printk(KERN_WARNING "blkfront: vdevice 0x%x might conflict with " 554 "emulated IDE disks,\n\t choose an xvd device name" 555 "from xvde on\n", info->vdevice); 556 } 557 err = -ENODEV; 558 559 if ((minor % nr_parts) == 0) 560 nr_minors = nr_parts; 561 562 err = xlbd_reserve_minors(minor, nr_minors); 563 if (err) 564 goto out; 565 err = -ENODEV; 566 567 gd = alloc_disk(nr_minors); 568 if (gd == NULL) 569 goto release; 570 571 if (nr_minors > 1) { 572 if (offset < 26) 573 sprintf(gd->disk_name, "%s%c", DEV_NAME, 'a' + offset); 574 else 575 sprintf(gd->disk_name, "%s%c%c", DEV_NAME, 576 'a' + ((offset / 26)-1), 'a' + (offset % 26)); 577 } else { 578 if (offset < 26) 579 sprintf(gd->disk_name, "%s%c%d", DEV_NAME, 580 'a' + offset, 581 minor & (nr_parts - 1)); 582 else 583 sprintf(gd->disk_name, "%s%c%c%d", DEV_NAME, 584 'a' + ((offset / 26) - 1), 585 'a' + (offset % 26), 586 minor & (nr_parts - 1)); 587 } 588 589 gd->major = XENVBD_MAJOR; 590 gd->first_minor = minor; 591 gd->fops = &xlvbd_block_fops; 592 gd->private_data = info; 593 gd->driverfs_dev = &(info->xbdev->dev); 594 set_capacity(gd, capacity); 595 596 if (xlvbd_init_blk_queue(gd, sector_size)) { 597 del_gendisk(gd); 598 goto release; 599 } 600 601 info->rq = gd->queue; 602 info->gd = gd; 603 604 xlvbd_flush(info); 605 606 if (vdisk_info & VDISK_READONLY) 607 set_disk_ro(gd, 1); 608 609 if (vdisk_info & VDISK_REMOVABLE) 610 gd->flags |= GENHD_FL_REMOVABLE; 611 612 if (vdisk_info & VDISK_CDROM) 613 gd->flags |= GENHD_FL_CD; 614 615 return 0; 616 617 release: 618 xlbd_release_minors(minor, nr_minors); 619 out: 620 return err; 621 } 622 623 static void xlvbd_release_gendisk(struct blkfront_info *info) 624 { 625 unsigned int minor, nr_minors; 626 unsigned long flags; 627 628 if (info->rq == NULL) 629 return; 630 631 spin_lock_irqsave(&blkif_io_lock, flags); 632 633 /* No more blkif_request(). */ 634 blk_stop_queue(info->rq); 635 636 /* No more gnttab callback work. */ 637 gnttab_cancel_free_callback(&info->callback); 638 spin_unlock_irqrestore(&blkif_io_lock, flags); 639 640 /* Flush gnttab callback work. Must be done with no locks held. */ 641 flush_work_sync(&info->work); 642 643 del_gendisk(info->gd); 644 645 minor = info->gd->first_minor; 646 nr_minors = info->gd->minors; 647 xlbd_release_minors(minor, nr_minors); 648 649 blk_cleanup_queue(info->rq); 650 info->rq = NULL; 651 652 put_disk(info->gd); 653 info->gd = NULL; 654 } 655 656 static void kick_pending_request_queues(struct blkfront_info *info) 657 { 658 if (!RING_FULL(&info->ring)) { 659 /* Re-enable calldowns. */ 660 blk_start_queue(info->rq); 661 /* Kick things off immediately. */ 662 do_blkif_request(info->rq); 663 } 664 } 665 666 static void blkif_restart_queue(struct work_struct *work) 667 { 668 struct blkfront_info *info = container_of(work, struct blkfront_info, work); 669 670 spin_lock_irq(&blkif_io_lock); 671 if (info->connected == BLKIF_STATE_CONNECTED) 672 kick_pending_request_queues(info); 673 spin_unlock_irq(&blkif_io_lock); 674 } 675 676 static void blkif_free(struct blkfront_info *info, int suspend) 677 { 678 /* Prevent new requests being issued until we fix things up. */ 679 spin_lock_irq(&blkif_io_lock); 680 info->connected = suspend ? 681 BLKIF_STATE_SUSPENDED : BLKIF_STATE_DISCONNECTED; 682 /* No more blkif_request(). */ 683 if (info->rq) 684 blk_stop_queue(info->rq); 685 /* No more gnttab callback work. */ 686 gnttab_cancel_free_callback(&info->callback); 687 spin_unlock_irq(&blkif_io_lock); 688 689 /* Flush gnttab callback work. Must be done with no locks held. */ 690 flush_work_sync(&info->work); 691 692 /* Free resources associated with old device channel. */ 693 if (info->ring_ref != GRANT_INVALID_REF) { 694 gnttab_end_foreign_access(info->ring_ref, 0, 695 (unsigned long)info->ring.sring); 696 info->ring_ref = GRANT_INVALID_REF; 697 info->ring.sring = NULL; 698 } 699 if (info->irq) 700 unbind_from_irqhandler(info->irq, info); 701 info->evtchn = info->irq = 0; 702 703 } 704 705 static void blkif_completion(struct blk_shadow *s) 706 { 707 int i; 708 for (i = 0; i < s->req.nr_segments; i++) 709 gnttab_end_foreign_access(s->req.u.rw.seg[i].gref, 0, 0UL); 710 } 711 712 static irqreturn_t blkif_interrupt(int irq, void *dev_id) 713 { 714 struct request *req; 715 struct blkif_response *bret; 716 RING_IDX i, rp; 717 unsigned long flags; 718 struct blkfront_info *info = (struct blkfront_info *)dev_id; 719 int error; 720 721 spin_lock_irqsave(&blkif_io_lock, flags); 722 723 if (unlikely(info->connected != BLKIF_STATE_CONNECTED)) { 724 spin_unlock_irqrestore(&blkif_io_lock, flags); 725 return IRQ_HANDLED; 726 } 727 728 again: 729 rp = info->ring.sring->rsp_prod; 730 rmb(); /* Ensure we see queued responses up to 'rp'. */ 731 732 for (i = info->ring.rsp_cons; i != rp; i++) { 733 unsigned long id; 734 735 bret = RING_GET_RESPONSE(&info->ring, i); 736 id = bret->id; 737 req = info->shadow[id].request; 738 739 blkif_completion(&info->shadow[id]); 740 741 add_id_to_freelist(info, id); 742 743 error = (bret->status == BLKIF_RSP_OKAY) ? 0 : -EIO; 744 switch (bret->operation) { 745 case BLKIF_OP_DISCARD: 746 if (unlikely(bret->status == BLKIF_RSP_EOPNOTSUPP)) { 747 struct request_queue *rq = info->rq; 748 printk(KERN_WARNING "blkfront: %s: discard op failed\n", 749 info->gd->disk_name); 750 error = -EOPNOTSUPP; 751 info->feature_discard = 0; 752 queue_flag_clear(QUEUE_FLAG_DISCARD, rq); 753 } 754 __blk_end_request_all(req, error); 755 break; 756 case BLKIF_OP_FLUSH_DISKCACHE: 757 case BLKIF_OP_WRITE_BARRIER: 758 if (unlikely(bret->status == BLKIF_RSP_EOPNOTSUPP)) { 759 printk(KERN_WARNING "blkfront: %s: write %s op failed\n", 760 info->flush_op == BLKIF_OP_WRITE_BARRIER ? 761 "barrier" : "flush disk cache", 762 info->gd->disk_name); 763 error = -EOPNOTSUPP; 764 } 765 if (unlikely(bret->status == BLKIF_RSP_ERROR && 766 info->shadow[id].req.nr_segments == 0)) { 767 printk(KERN_WARNING "blkfront: %s: empty write %s op failed\n", 768 info->flush_op == BLKIF_OP_WRITE_BARRIER ? 769 "barrier" : "flush disk cache", 770 info->gd->disk_name); 771 error = -EOPNOTSUPP; 772 } 773 if (unlikely(error)) { 774 if (error == -EOPNOTSUPP) 775 error = 0; 776 info->feature_flush = 0; 777 info->flush_op = 0; 778 xlvbd_flush(info); 779 } 780 /* fall through */ 781 case BLKIF_OP_READ: 782 case BLKIF_OP_WRITE: 783 if (unlikely(bret->status != BLKIF_RSP_OKAY)) 784 dev_dbg(&info->xbdev->dev, "Bad return from blkdev data " 785 "request: %x\n", bret->status); 786 787 __blk_end_request_all(req, error); 788 break; 789 default: 790 BUG(); 791 } 792 } 793 794 info->ring.rsp_cons = i; 795 796 if (i != info->ring.req_prod_pvt) { 797 int more_to_do; 798 RING_FINAL_CHECK_FOR_RESPONSES(&info->ring, more_to_do); 799 if (more_to_do) 800 goto again; 801 } else 802 info->ring.sring->rsp_event = i + 1; 803 804 kick_pending_request_queues(info); 805 806 spin_unlock_irqrestore(&blkif_io_lock, flags); 807 808 return IRQ_HANDLED; 809 } 810 811 812 static int setup_blkring(struct xenbus_device *dev, 813 struct blkfront_info *info) 814 { 815 struct blkif_sring *sring; 816 int err; 817 818 info->ring_ref = GRANT_INVALID_REF; 819 820 sring = (struct blkif_sring *)__get_free_page(GFP_NOIO | __GFP_HIGH); 821 if (!sring) { 822 xenbus_dev_fatal(dev, -ENOMEM, "allocating shared ring"); 823 return -ENOMEM; 824 } 825 SHARED_RING_INIT(sring); 826 FRONT_RING_INIT(&info->ring, sring, PAGE_SIZE); 827 828 sg_init_table(info->sg, BLKIF_MAX_SEGMENTS_PER_REQUEST); 829 830 err = xenbus_grant_ring(dev, virt_to_mfn(info->ring.sring)); 831 if (err < 0) { 832 free_page((unsigned long)sring); 833 info->ring.sring = NULL; 834 goto fail; 835 } 836 info->ring_ref = err; 837 838 err = xenbus_alloc_evtchn(dev, &info->evtchn); 839 if (err) 840 goto fail; 841 842 err = bind_evtchn_to_irqhandler(info->evtchn, 843 blkif_interrupt, 844 IRQF_SAMPLE_RANDOM, "blkif", info); 845 if (err <= 0) { 846 xenbus_dev_fatal(dev, err, 847 "bind_evtchn_to_irqhandler failed"); 848 goto fail; 849 } 850 info->irq = err; 851 852 return 0; 853 fail: 854 blkif_free(info, 0); 855 return err; 856 } 857 858 859 /* Common code used when first setting up, and when resuming. */ 860 static int talk_to_blkback(struct xenbus_device *dev, 861 struct blkfront_info *info) 862 { 863 const char *message = NULL; 864 struct xenbus_transaction xbt; 865 int err; 866 867 /* Create shared ring, alloc event channel. */ 868 err = setup_blkring(dev, info); 869 if (err) 870 goto out; 871 872 again: 873 err = xenbus_transaction_start(&xbt); 874 if (err) { 875 xenbus_dev_fatal(dev, err, "starting transaction"); 876 goto destroy_blkring; 877 } 878 879 err = xenbus_printf(xbt, dev->nodename, 880 "ring-ref", "%u", info->ring_ref); 881 if (err) { 882 message = "writing ring-ref"; 883 goto abort_transaction; 884 } 885 err = xenbus_printf(xbt, dev->nodename, 886 "event-channel", "%u", info->evtchn); 887 if (err) { 888 message = "writing event-channel"; 889 goto abort_transaction; 890 } 891 err = xenbus_printf(xbt, dev->nodename, "protocol", "%s", 892 XEN_IO_PROTO_ABI_NATIVE); 893 if (err) { 894 message = "writing protocol"; 895 goto abort_transaction; 896 } 897 898 err = xenbus_transaction_end(xbt, 0); 899 if (err) { 900 if (err == -EAGAIN) 901 goto again; 902 xenbus_dev_fatal(dev, err, "completing transaction"); 903 goto destroy_blkring; 904 } 905 906 xenbus_switch_state(dev, XenbusStateInitialised); 907 908 return 0; 909 910 abort_transaction: 911 xenbus_transaction_end(xbt, 1); 912 if (message) 913 xenbus_dev_fatal(dev, err, "%s", message); 914 destroy_blkring: 915 blkif_free(info, 0); 916 out: 917 return err; 918 } 919 920 /** 921 * Entry point to this code when a new device is created. Allocate the basic 922 * structures and the ring buffer for communication with the backend, and 923 * inform the backend of the appropriate details for those. Switch to 924 * Initialised state. 925 */ 926 static int blkfront_probe(struct xenbus_device *dev, 927 const struct xenbus_device_id *id) 928 { 929 int err, vdevice, i; 930 struct blkfront_info *info; 931 932 /* FIXME: Use dynamic device id if this is not set. */ 933 err = xenbus_scanf(XBT_NIL, dev->nodename, 934 "virtual-device", "%i", &vdevice); 935 if (err != 1) { 936 /* go looking in the extended area instead */ 937 err = xenbus_scanf(XBT_NIL, dev->nodename, "virtual-device-ext", 938 "%i", &vdevice); 939 if (err != 1) { 940 xenbus_dev_fatal(dev, err, "reading virtual-device"); 941 return err; 942 } 943 } 944 945 if (xen_hvm_domain()) { 946 char *type; 947 int len; 948 /* no unplug has been done: do not hook devices != xen vbds */ 949 if (xen_platform_pci_unplug & XEN_UNPLUG_UNNECESSARY) { 950 int major; 951 952 if (!VDEV_IS_EXTENDED(vdevice)) 953 major = BLKIF_MAJOR(vdevice); 954 else 955 major = XENVBD_MAJOR; 956 957 if (major != XENVBD_MAJOR) { 958 printk(KERN_INFO 959 "%s: HVM does not support vbd %d as xen block device\n", 960 __FUNCTION__, vdevice); 961 return -ENODEV; 962 } 963 } 964 /* do not create a PV cdrom device if we are an HVM guest */ 965 type = xenbus_read(XBT_NIL, dev->nodename, "device-type", &len); 966 if (IS_ERR(type)) 967 return -ENODEV; 968 if (strncmp(type, "cdrom", 5) == 0) { 969 kfree(type); 970 return -ENODEV; 971 } 972 kfree(type); 973 } 974 info = kzalloc(sizeof(*info), GFP_KERNEL); 975 if (!info) { 976 xenbus_dev_fatal(dev, -ENOMEM, "allocating info structure"); 977 return -ENOMEM; 978 } 979 980 mutex_init(&info->mutex); 981 info->xbdev = dev; 982 info->vdevice = vdevice; 983 info->connected = BLKIF_STATE_DISCONNECTED; 984 INIT_WORK(&info->work, blkif_restart_queue); 985 986 for (i = 0; i < BLK_RING_SIZE; i++) 987 info->shadow[i].req.id = i+1; 988 info->shadow[BLK_RING_SIZE-1].req.id = 0x0fffffff; 989 990 /* Front end dir is a number, which is used as the id. */ 991 info->handle = simple_strtoul(strrchr(dev->nodename, '/')+1, NULL, 0); 992 dev_set_drvdata(&dev->dev, info); 993 994 err = talk_to_blkback(dev, info); 995 if (err) { 996 kfree(info); 997 dev_set_drvdata(&dev->dev, NULL); 998 return err; 999 } 1000 1001 return 0; 1002 } 1003 1004 1005 static int blkif_recover(struct blkfront_info *info) 1006 { 1007 int i; 1008 struct blkif_request *req; 1009 struct blk_shadow *copy; 1010 int j; 1011 1012 /* Stage 1: Make a safe copy of the shadow state. */ 1013 copy = kmalloc(sizeof(info->shadow), 1014 GFP_NOIO | __GFP_REPEAT | __GFP_HIGH); 1015 if (!copy) 1016 return -ENOMEM; 1017 memcpy(copy, info->shadow, sizeof(info->shadow)); 1018 1019 /* Stage 2: Set up free list. */ 1020 memset(&info->shadow, 0, sizeof(info->shadow)); 1021 for (i = 0; i < BLK_RING_SIZE; i++) 1022 info->shadow[i].req.id = i+1; 1023 info->shadow_free = info->ring.req_prod_pvt; 1024 info->shadow[BLK_RING_SIZE-1].req.id = 0x0fffffff; 1025 1026 /* Stage 3: Find pending requests and requeue them. */ 1027 for (i = 0; i < BLK_RING_SIZE; i++) { 1028 /* Not in use? */ 1029 if (!copy[i].request) 1030 continue; 1031 1032 /* Grab a request slot and copy shadow state into it. */ 1033 req = RING_GET_REQUEST(&info->ring, info->ring.req_prod_pvt); 1034 *req = copy[i].req; 1035 1036 /* We get a new request id, and must reset the shadow state. */ 1037 req->id = get_id_from_freelist(info); 1038 memcpy(&info->shadow[req->id], ©[i], sizeof(copy[i])); 1039 1040 /* Rewrite any grant references invalidated by susp/resume. */ 1041 for (j = 0; j < req->nr_segments; j++) 1042 gnttab_grant_foreign_access_ref( 1043 req->u.rw.seg[j].gref, 1044 info->xbdev->otherend_id, 1045 pfn_to_mfn(info->shadow[req->id].frame[j]), 1046 rq_data_dir(info->shadow[req->id].request)); 1047 info->shadow[req->id].req = *req; 1048 1049 info->ring.req_prod_pvt++; 1050 } 1051 1052 kfree(copy); 1053 1054 xenbus_switch_state(info->xbdev, XenbusStateConnected); 1055 1056 spin_lock_irq(&blkif_io_lock); 1057 1058 /* Now safe for us to use the shared ring */ 1059 info->connected = BLKIF_STATE_CONNECTED; 1060 1061 /* Send off requeued requests */ 1062 flush_requests(info); 1063 1064 /* Kick any other new requests queued since we resumed */ 1065 kick_pending_request_queues(info); 1066 1067 spin_unlock_irq(&blkif_io_lock); 1068 1069 return 0; 1070 } 1071 1072 /** 1073 * We are reconnecting to the backend, due to a suspend/resume, or a backend 1074 * driver restart. We tear down our blkif structure and recreate it, but 1075 * leave the device-layer structures intact so that this is transparent to the 1076 * rest of the kernel. 1077 */ 1078 static int blkfront_resume(struct xenbus_device *dev) 1079 { 1080 struct blkfront_info *info = dev_get_drvdata(&dev->dev); 1081 int err; 1082 1083 dev_dbg(&dev->dev, "blkfront_resume: %s\n", dev->nodename); 1084 1085 blkif_free(info, info->connected == BLKIF_STATE_CONNECTED); 1086 1087 err = talk_to_blkback(dev, info); 1088 if (info->connected == BLKIF_STATE_SUSPENDED && !err) 1089 err = blkif_recover(info); 1090 1091 return err; 1092 } 1093 1094 static void 1095 blkfront_closing(struct blkfront_info *info) 1096 { 1097 struct xenbus_device *xbdev = info->xbdev; 1098 struct block_device *bdev = NULL; 1099 1100 mutex_lock(&info->mutex); 1101 1102 if (xbdev->state == XenbusStateClosing) { 1103 mutex_unlock(&info->mutex); 1104 return; 1105 } 1106 1107 if (info->gd) 1108 bdev = bdget_disk(info->gd, 0); 1109 1110 mutex_unlock(&info->mutex); 1111 1112 if (!bdev) { 1113 xenbus_frontend_closed(xbdev); 1114 return; 1115 } 1116 1117 mutex_lock(&bdev->bd_mutex); 1118 1119 if (bdev->bd_openers) { 1120 xenbus_dev_error(xbdev, -EBUSY, 1121 "Device in use; refusing to close"); 1122 xenbus_switch_state(xbdev, XenbusStateClosing); 1123 } else { 1124 xlvbd_release_gendisk(info); 1125 xenbus_frontend_closed(xbdev); 1126 } 1127 1128 mutex_unlock(&bdev->bd_mutex); 1129 bdput(bdev); 1130 } 1131 1132 static void blkfront_setup_discard(struct blkfront_info *info) 1133 { 1134 int err; 1135 char *type; 1136 unsigned int discard_granularity; 1137 unsigned int discard_alignment; 1138 1139 type = xenbus_read(XBT_NIL, info->xbdev->otherend, "type", NULL); 1140 if (IS_ERR(type)) 1141 return; 1142 1143 if (strncmp(type, "phy", 3) == 0) { 1144 err = xenbus_gather(XBT_NIL, info->xbdev->otherend, 1145 "discard-granularity", "%u", &discard_granularity, 1146 "discard-alignment", "%u", &discard_alignment, 1147 NULL); 1148 if (!err) { 1149 info->feature_discard = 1; 1150 info->discard_granularity = discard_granularity; 1151 info->discard_alignment = discard_alignment; 1152 } 1153 } else if (strncmp(type, "file", 4) == 0) 1154 info->feature_discard = 1; 1155 1156 kfree(type); 1157 } 1158 1159 /* 1160 * Invoked when the backend is finally 'ready' (and has told produced 1161 * the details about the physical device - #sectors, size, etc). 1162 */ 1163 static void blkfront_connect(struct blkfront_info *info) 1164 { 1165 unsigned long long sectors; 1166 unsigned long sector_size; 1167 unsigned int binfo; 1168 int err; 1169 int barrier, flush, discard; 1170 1171 switch (info->connected) { 1172 case BLKIF_STATE_CONNECTED: 1173 /* 1174 * Potentially, the back-end may be signalling 1175 * a capacity change; update the capacity. 1176 */ 1177 err = xenbus_scanf(XBT_NIL, info->xbdev->otherend, 1178 "sectors", "%Lu", §ors); 1179 if (XENBUS_EXIST_ERR(err)) 1180 return; 1181 printk(KERN_INFO "Setting capacity to %Lu\n", 1182 sectors); 1183 set_capacity(info->gd, sectors); 1184 revalidate_disk(info->gd); 1185 1186 /* fall through */ 1187 case BLKIF_STATE_SUSPENDED: 1188 return; 1189 1190 default: 1191 break; 1192 } 1193 1194 dev_dbg(&info->xbdev->dev, "%s:%s.\n", 1195 __func__, info->xbdev->otherend); 1196 1197 err = xenbus_gather(XBT_NIL, info->xbdev->otherend, 1198 "sectors", "%llu", §ors, 1199 "info", "%u", &binfo, 1200 "sector-size", "%lu", §or_size, 1201 NULL); 1202 if (err) { 1203 xenbus_dev_fatal(info->xbdev, err, 1204 "reading backend fields at %s", 1205 info->xbdev->otherend); 1206 return; 1207 } 1208 1209 info->feature_flush = 0; 1210 info->flush_op = 0; 1211 1212 err = xenbus_gather(XBT_NIL, info->xbdev->otherend, 1213 "feature-barrier", "%d", &barrier, 1214 NULL); 1215 1216 /* 1217 * If there's no "feature-barrier" defined, then it means 1218 * we're dealing with a very old backend which writes 1219 * synchronously; nothing to do. 1220 * 1221 * If there are barriers, then we use flush. 1222 */ 1223 if (!err && barrier) { 1224 info->feature_flush = REQ_FLUSH | REQ_FUA; 1225 info->flush_op = BLKIF_OP_WRITE_BARRIER; 1226 } 1227 /* 1228 * And if there is "feature-flush-cache" use that above 1229 * barriers. 1230 */ 1231 err = xenbus_gather(XBT_NIL, info->xbdev->otherend, 1232 "feature-flush-cache", "%d", &flush, 1233 NULL); 1234 1235 if (!err && flush) { 1236 info->feature_flush = REQ_FLUSH; 1237 info->flush_op = BLKIF_OP_FLUSH_DISKCACHE; 1238 } 1239 1240 err = xenbus_gather(XBT_NIL, info->xbdev->otherend, 1241 "feature-discard", "%d", &discard, 1242 NULL); 1243 1244 if (!err && discard) 1245 blkfront_setup_discard(info); 1246 1247 err = xlvbd_alloc_gendisk(sectors, info, binfo, sector_size); 1248 if (err) { 1249 xenbus_dev_fatal(info->xbdev, err, "xlvbd_add at %s", 1250 info->xbdev->otherend); 1251 return; 1252 } 1253 1254 xenbus_switch_state(info->xbdev, XenbusStateConnected); 1255 1256 /* Kick pending requests. */ 1257 spin_lock_irq(&blkif_io_lock); 1258 info->connected = BLKIF_STATE_CONNECTED; 1259 kick_pending_request_queues(info); 1260 spin_unlock_irq(&blkif_io_lock); 1261 1262 add_disk(info->gd); 1263 1264 info->is_ready = 1; 1265 } 1266 1267 /** 1268 * Callback received when the backend's state changes. 1269 */ 1270 static void blkback_changed(struct xenbus_device *dev, 1271 enum xenbus_state backend_state) 1272 { 1273 struct blkfront_info *info = dev_get_drvdata(&dev->dev); 1274 1275 dev_dbg(&dev->dev, "blkfront:blkback_changed to state %d.\n", backend_state); 1276 1277 switch (backend_state) { 1278 case XenbusStateInitialising: 1279 case XenbusStateInitWait: 1280 case XenbusStateInitialised: 1281 case XenbusStateReconfiguring: 1282 case XenbusStateReconfigured: 1283 case XenbusStateUnknown: 1284 case XenbusStateClosed: 1285 break; 1286 1287 case XenbusStateConnected: 1288 blkfront_connect(info); 1289 break; 1290 1291 case XenbusStateClosing: 1292 blkfront_closing(info); 1293 break; 1294 } 1295 } 1296 1297 static int blkfront_remove(struct xenbus_device *xbdev) 1298 { 1299 struct blkfront_info *info = dev_get_drvdata(&xbdev->dev); 1300 struct block_device *bdev = NULL; 1301 struct gendisk *disk; 1302 1303 dev_dbg(&xbdev->dev, "%s removed", xbdev->nodename); 1304 1305 blkif_free(info, 0); 1306 1307 mutex_lock(&info->mutex); 1308 1309 disk = info->gd; 1310 if (disk) 1311 bdev = bdget_disk(disk, 0); 1312 1313 info->xbdev = NULL; 1314 mutex_unlock(&info->mutex); 1315 1316 if (!bdev) { 1317 kfree(info); 1318 return 0; 1319 } 1320 1321 /* 1322 * The xbdev was removed before we reached the Closed 1323 * state. See if it's safe to remove the disk. If the bdev 1324 * isn't closed yet, we let release take care of it. 1325 */ 1326 1327 mutex_lock(&bdev->bd_mutex); 1328 info = disk->private_data; 1329 1330 dev_warn(disk_to_dev(disk), 1331 "%s was hot-unplugged, %d stale handles\n", 1332 xbdev->nodename, bdev->bd_openers); 1333 1334 if (info && !bdev->bd_openers) { 1335 xlvbd_release_gendisk(info); 1336 disk->private_data = NULL; 1337 kfree(info); 1338 } 1339 1340 mutex_unlock(&bdev->bd_mutex); 1341 bdput(bdev); 1342 1343 return 0; 1344 } 1345 1346 static int blkfront_is_ready(struct xenbus_device *dev) 1347 { 1348 struct blkfront_info *info = dev_get_drvdata(&dev->dev); 1349 1350 return info->is_ready && info->xbdev; 1351 } 1352 1353 static int blkif_open(struct block_device *bdev, fmode_t mode) 1354 { 1355 struct gendisk *disk = bdev->bd_disk; 1356 struct blkfront_info *info; 1357 int err = 0; 1358 1359 mutex_lock(&blkfront_mutex); 1360 1361 info = disk->private_data; 1362 if (!info) { 1363 /* xbdev gone */ 1364 err = -ERESTARTSYS; 1365 goto out; 1366 } 1367 1368 mutex_lock(&info->mutex); 1369 1370 if (!info->gd) 1371 /* xbdev is closed */ 1372 err = -ERESTARTSYS; 1373 1374 mutex_unlock(&info->mutex); 1375 1376 out: 1377 mutex_unlock(&blkfront_mutex); 1378 return err; 1379 } 1380 1381 static int blkif_release(struct gendisk *disk, fmode_t mode) 1382 { 1383 struct blkfront_info *info = disk->private_data; 1384 struct block_device *bdev; 1385 struct xenbus_device *xbdev; 1386 1387 mutex_lock(&blkfront_mutex); 1388 1389 bdev = bdget_disk(disk, 0); 1390 bdput(bdev); 1391 1392 if (bdev->bd_openers) 1393 goto out; 1394 1395 /* 1396 * Check if we have been instructed to close. We will have 1397 * deferred this request, because the bdev was still open. 1398 */ 1399 1400 mutex_lock(&info->mutex); 1401 xbdev = info->xbdev; 1402 1403 if (xbdev && xbdev->state == XenbusStateClosing) { 1404 /* pending switch to state closed */ 1405 dev_info(disk_to_dev(bdev->bd_disk), "releasing disk\n"); 1406 xlvbd_release_gendisk(info); 1407 xenbus_frontend_closed(info->xbdev); 1408 } 1409 1410 mutex_unlock(&info->mutex); 1411 1412 if (!xbdev) { 1413 /* sudden device removal */ 1414 dev_info(disk_to_dev(bdev->bd_disk), "releasing disk\n"); 1415 xlvbd_release_gendisk(info); 1416 disk->private_data = NULL; 1417 kfree(info); 1418 } 1419 1420 out: 1421 mutex_unlock(&blkfront_mutex); 1422 return 0; 1423 } 1424 1425 static const struct block_device_operations xlvbd_block_fops = 1426 { 1427 .owner = THIS_MODULE, 1428 .open = blkif_open, 1429 .release = blkif_release, 1430 .getgeo = blkif_getgeo, 1431 .ioctl = blkif_ioctl, 1432 }; 1433 1434 1435 static const struct xenbus_device_id blkfront_ids[] = { 1436 { "vbd" }, 1437 { "" } 1438 }; 1439 1440 static struct xenbus_driver blkfront = { 1441 .name = "vbd", 1442 .owner = THIS_MODULE, 1443 .ids = blkfront_ids, 1444 .probe = blkfront_probe, 1445 .remove = blkfront_remove, 1446 .resume = blkfront_resume, 1447 .otherend_changed = blkback_changed, 1448 .is_ready = blkfront_is_ready, 1449 }; 1450 1451 static int __init xlblk_init(void) 1452 { 1453 int ret; 1454 1455 if (!xen_domain()) 1456 return -ENODEV; 1457 1458 if (register_blkdev(XENVBD_MAJOR, DEV_NAME)) { 1459 printk(KERN_WARNING "xen_blk: can't get major %d with name %s\n", 1460 XENVBD_MAJOR, DEV_NAME); 1461 return -ENODEV; 1462 } 1463 1464 ret = xenbus_register_frontend(&blkfront); 1465 if (ret) { 1466 unregister_blkdev(XENVBD_MAJOR, DEV_NAME); 1467 return ret; 1468 } 1469 1470 return 0; 1471 } 1472 module_init(xlblk_init); 1473 1474 1475 static void __exit xlblk_exit(void) 1476 { 1477 return xenbus_unregister_driver(&blkfront); 1478 } 1479 module_exit(xlblk_exit); 1480 1481 MODULE_DESCRIPTION("Xen virtual block device frontend"); 1482 MODULE_LICENSE("GPL"); 1483 MODULE_ALIAS_BLOCKDEV_MAJOR(XENVBD_MAJOR); 1484 MODULE_ALIAS("xen:vbd"); 1485 MODULE_ALIAS("xenblk"); 1486