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 48 #include <xen/xen.h> 49 #include <xen/xenbus.h> 50 #include <xen/grant_table.h> 51 #include <xen/events.h> 52 #include <xen/page.h> 53 #include <xen/platform_pci.h> 54 55 #include <xen/interface/grant_table.h> 56 #include <xen/interface/io/blkif.h> 57 #include <xen/interface/io/protocols.h> 58 59 #include <asm/xen/hypervisor.h> 60 61 enum blkif_state { 62 BLKIF_STATE_DISCONNECTED, 63 BLKIF_STATE_CONNECTED, 64 BLKIF_STATE_SUSPENDED, 65 }; 66 67 struct blk_shadow { 68 struct blkif_request req; 69 struct request *request; 70 unsigned long frame[BLKIF_MAX_SEGMENTS_PER_REQUEST]; 71 }; 72 73 static DEFINE_MUTEX(blkfront_mutex); 74 static const struct block_device_operations xlvbd_block_fops; 75 76 #define BLK_RING_SIZE __CONST_RING_SIZE(blkif, PAGE_SIZE) 77 78 /* 79 * We have one of these per vbd, whether ide, scsi or 'other'. They 80 * hang in private_data off the gendisk structure. We may end up 81 * putting all kinds of interesting stuff here :-) 82 */ 83 struct blkfront_info 84 { 85 spinlock_t io_lock; 86 struct mutex mutex; 87 struct xenbus_device *xbdev; 88 struct gendisk *gd; 89 int vdevice; 90 blkif_vdev_t handle; 91 enum blkif_state connected; 92 int ring_ref; 93 struct blkif_front_ring ring; 94 struct scatterlist sg[BLKIF_MAX_SEGMENTS_PER_REQUEST]; 95 unsigned int evtchn, irq; 96 struct request_queue *rq; 97 struct work_struct work; 98 struct gnttab_free_callback callback; 99 struct blk_shadow shadow[BLK_RING_SIZE]; 100 unsigned long shadow_free; 101 unsigned int feature_flush; 102 unsigned int flush_op; 103 unsigned int feature_discard:1; 104 unsigned int feature_secdiscard:1; 105 unsigned int discard_granularity; 106 unsigned int discard_alignment; 107 int is_ready; 108 }; 109 110 static unsigned int nr_minors; 111 static unsigned long *minors; 112 static DEFINE_SPINLOCK(minor_lock); 113 114 #define MAXIMUM_OUTSTANDING_BLOCK_REQS \ 115 (BLKIF_MAX_SEGMENTS_PER_REQUEST * BLK_RING_SIZE) 116 #define GRANT_INVALID_REF 0 117 118 #define PARTS_PER_DISK 16 119 #define PARTS_PER_EXT_DISK 256 120 121 #define BLKIF_MAJOR(dev) ((dev)>>8) 122 #define BLKIF_MINOR(dev) ((dev) & 0xff) 123 124 #define EXT_SHIFT 28 125 #define EXTENDED (1<<EXT_SHIFT) 126 #define VDEV_IS_EXTENDED(dev) ((dev)&(EXTENDED)) 127 #define BLKIF_MINOR_EXT(dev) ((dev)&(~EXTENDED)) 128 #define EMULATED_HD_DISK_MINOR_OFFSET (0) 129 #define EMULATED_HD_DISK_NAME_OFFSET (EMULATED_HD_DISK_MINOR_OFFSET / 256) 130 #define EMULATED_SD_DISK_MINOR_OFFSET (0) 131 #define EMULATED_SD_DISK_NAME_OFFSET (EMULATED_SD_DISK_MINOR_OFFSET / 256) 132 133 #define DEV_NAME "xvd" /* name in /dev */ 134 135 static int get_id_from_freelist(struct blkfront_info *info) 136 { 137 unsigned long free = info->shadow_free; 138 BUG_ON(free >= BLK_RING_SIZE); 139 info->shadow_free = info->shadow[free].req.u.rw.id; 140 info->shadow[free].req.u.rw.id = 0x0fffffee; /* debug */ 141 return free; 142 } 143 144 static void add_id_to_freelist(struct blkfront_info *info, 145 unsigned long id) 146 { 147 info->shadow[id].req.u.rw.id = info->shadow_free; 148 info->shadow[id].request = NULL; 149 info->shadow_free = id; 150 } 151 152 static int xlbd_reserve_minors(unsigned int minor, unsigned int nr) 153 { 154 unsigned int end = minor + nr; 155 int rc; 156 157 if (end > nr_minors) { 158 unsigned long *bitmap, *old; 159 160 bitmap = kcalloc(BITS_TO_LONGS(end), sizeof(*bitmap), 161 GFP_KERNEL); 162 if (bitmap == NULL) 163 return -ENOMEM; 164 165 spin_lock(&minor_lock); 166 if (end > nr_minors) { 167 old = minors; 168 memcpy(bitmap, minors, 169 BITS_TO_LONGS(nr_minors) * sizeof(*bitmap)); 170 minors = bitmap; 171 nr_minors = BITS_TO_LONGS(end) * BITS_PER_LONG; 172 } else 173 old = bitmap; 174 spin_unlock(&minor_lock); 175 kfree(old); 176 } 177 178 spin_lock(&minor_lock); 179 if (find_next_bit(minors, end, minor) >= end) { 180 bitmap_set(minors, minor, nr); 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 bitmap_clear(minors, minor, nr); 196 spin_unlock(&minor_lock); 197 } 198 199 static void blkif_restart_queue_callback(void *arg) 200 { 201 struct blkfront_info *info = (struct blkfront_info *)arg; 202 schedule_work(&info->work); 203 } 204 205 static int blkif_getgeo(struct block_device *bd, struct hd_geometry *hg) 206 { 207 /* We don't have real geometry info, but let's at least return 208 values consistent with the size of the device */ 209 sector_t nsect = get_capacity(bd->bd_disk); 210 sector_t cylinders = nsect; 211 212 hg->heads = 0xff; 213 hg->sectors = 0x3f; 214 sector_div(cylinders, hg->heads * hg->sectors); 215 hg->cylinders = cylinders; 216 if ((sector_t)(hg->cylinders + 1) * hg->heads * hg->sectors < nsect) 217 hg->cylinders = 0xffff; 218 return 0; 219 } 220 221 static int blkif_ioctl(struct block_device *bdev, fmode_t mode, 222 unsigned command, unsigned long argument) 223 { 224 struct blkfront_info *info = bdev->bd_disk->private_data; 225 int i; 226 227 dev_dbg(&info->xbdev->dev, "command: 0x%x, argument: 0x%lx\n", 228 command, (long)argument); 229 230 switch (command) { 231 case CDROMMULTISESSION: 232 dev_dbg(&info->xbdev->dev, "FIXME: support multisession CDs later\n"); 233 for (i = 0; i < sizeof(struct cdrom_multisession); i++) 234 if (put_user(0, (char __user *)(argument + i))) 235 return -EFAULT; 236 return 0; 237 238 case CDROM_GET_CAPABILITY: { 239 struct gendisk *gd = info->gd; 240 if (gd->flags & GENHD_FL_CD) 241 return 0; 242 return -EINVAL; 243 } 244 245 default: 246 /*printk(KERN_ALERT "ioctl %08x not supported by Xen blkdev\n", 247 command);*/ 248 return -EINVAL; /* same return as native Linux */ 249 } 250 251 return 0; 252 } 253 254 /* 255 * Generate a Xen blkfront IO request from a blk layer request. Reads 256 * and writes are handled as expected. 257 * 258 * @req: a request struct 259 */ 260 static int blkif_queue_request(struct request *req) 261 { 262 struct blkfront_info *info = req->rq_disk->private_data; 263 unsigned long buffer_mfn; 264 struct blkif_request *ring_req; 265 unsigned long id; 266 unsigned int fsect, lsect; 267 int i, ref; 268 grant_ref_t gref_head; 269 struct scatterlist *sg; 270 271 if (unlikely(info->connected != BLKIF_STATE_CONNECTED)) 272 return 1; 273 274 if (gnttab_alloc_grant_references( 275 BLKIF_MAX_SEGMENTS_PER_REQUEST, &gref_head) < 0) { 276 gnttab_request_free_callback( 277 &info->callback, 278 blkif_restart_queue_callback, 279 info, 280 BLKIF_MAX_SEGMENTS_PER_REQUEST); 281 return 1; 282 } 283 284 /* Fill out a communications ring structure. */ 285 ring_req = RING_GET_REQUEST(&info->ring, info->ring.req_prod_pvt); 286 id = get_id_from_freelist(info); 287 info->shadow[id].request = req; 288 289 ring_req->u.rw.id = id; 290 ring_req->u.rw.sector_number = (blkif_sector_t)blk_rq_pos(req); 291 ring_req->u.rw.handle = info->handle; 292 293 ring_req->operation = rq_data_dir(req) ? 294 BLKIF_OP_WRITE : BLKIF_OP_READ; 295 296 if (req->cmd_flags & (REQ_FLUSH | REQ_FUA)) { 297 /* 298 * Ideally we can do an unordered flush-to-disk. In case the 299 * backend onlysupports barriers, use that. A barrier request 300 * a superset of FUA, so we can implement it the same 301 * way. (It's also a FLUSH+FUA, since it is 302 * guaranteed ordered WRT previous writes.) 303 */ 304 ring_req->operation = info->flush_op; 305 } 306 307 if (unlikely(req->cmd_flags & (REQ_DISCARD | REQ_SECURE))) { 308 /* id, sector_number and handle are set above. */ 309 ring_req->operation = BLKIF_OP_DISCARD; 310 ring_req->u.discard.nr_sectors = blk_rq_sectors(req); 311 if ((req->cmd_flags & REQ_SECURE) && info->feature_secdiscard) 312 ring_req->u.discard.flag = BLKIF_DISCARD_SECURE; 313 else 314 ring_req->u.discard.flag = 0; 315 } else { 316 ring_req->u.rw.nr_segments = blk_rq_map_sg(req->q, req, 317 info->sg); 318 BUG_ON(ring_req->u.rw.nr_segments > 319 BLKIF_MAX_SEGMENTS_PER_REQUEST); 320 321 for_each_sg(info->sg, sg, ring_req->u.rw.nr_segments, i) { 322 buffer_mfn = pfn_to_mfn(page_to_pfn(sg_page(sg))); 323 fsect = sg->offset >> 9; 324 lsect = fsect + (sg->length >> 9) - 1; 325 /* install a grant reference. */ 326 ref = gnttab_claim_grant_reference(&gref_head); 327 BUG_ON(ref == -ENOSPC); 328 329 gnttab_grant_foreign_access_ref( 330 ref, 331 info->xbdev->otherend_id, 332 buffer_mfn, 333 rq_data_dir(req)); 334 335 info->shadow[id].frame[i] = mfn_to_pfn(buffer_mfn); 336 ring_req->u.rw.seg[i] = 337 (struct blkif_request_segment) { 338 .gref = ref, 339 .first_sect = fsect, 340 .last_sect = lsect }; 341 } 342 } 343 344 info->ring.req_prod_pvt++; 345 346 /* Keep a private copy so we can reissue requests when recovering. */ 347 info->shadow[id].req = *ring_req; 348 349 gnttab_free_grant_references(gref_head); 350 351 return 0; 352 } 353 354 355 static inline void flush_requests(struct blkfront_info *info) 356 { 357 int notify; 358 359 RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&info->ring, notify); 360 361 if (notify) 362 notify_remote_via_irq(info->irq); 363 } 364 365 /* 366 * do_blkif_request 367 * read a block; request is in a request queue 368 */ 369 static void do_blkif_request(struct request_queue *rq) 370 { 371 struct blkfront_info *info = NULL; 372 struct request *req; 373 int queued; 374 375 pr_debug("Entered do_blkif_request\n"); 376 377 queued = 0; 378 379 while ((req = blk_peek_request(rq)) != NULL) { 380 info = req->rq_disk->private_data; 381 382 if (RING_FULL(&info->ring)) 383 goto wait; 384 385 blk_start_request(req); 386 387 if ((req->cmd_type != REQ_TYPE_FS) || 388 ((req->cmd_flags & (REQ_FLUSH | REQ_FUA)) && 389 !info->flush_op)) { 390 __blk_end_request_all(req, -EIO); 391 continue; 392 } 393 394 pr_debug("do_blk_req %p: cmd %p, sec %lx, " 395 "(%u/%u) buffer:%p [%s]\n", 396 req, req->cmd, (unsigned long)blk_rq_pos(req), 397 blk_rq_cur_sectors(req), blk_rq_sectors(req), 398 req->buffer, rq_data_dir(req) ? "write" : "read"); 399 400 if (blkif_queue_request(req)) { 401 blk_requeue_request(rq, req); 402 wait: 403 /* Avoid pointless unplugs. */ 404 blk_stop_queue(rq); 405 break; 406 } 407 408 queued++; 409 } 410 411 if (queued != 0) 412 flush_requests(info); 413 } 414 415 static int xlvbd_init_blk_queue(struct gendisk *gd, u16 sector_size) 416 { 417 struct request_queue *rq; 418 struct blkfront_info *info = gd->private_data; 419 420 rq = blk_init_queue(do_blkif_request, &info->io_lock); 421 if (rq == NULL) 422 return -1; 423 424 queue_flag_set_unlocked(QUEUE_FLAG_VIRT, rq); 425 426 if (info->feature_discard) { 427 queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, rq); 428 blk_queue_max_discard_sectors(rq, get_capacity(gd)); 429 rq->limits.discard_granularity = info->discard_granularity; 430 rq->limits.discard_alignment = info->discard_alignment; 431 if (info->feature_secdiscard) 432 queue_flag_set_unlocked(QUEUE_FLAG_SECDISCARD, rq); 433 } 434 435 /* Hard sector size and max sectors impersonate the equiv. hardware. */ 436 blk_queue_logical_block_size(rq, sector_size); 437 blk_queue_max_hw_sectors(rq, 512); 438 439 /* Each segment in a request is up to an aligned page in size. */ 440 blk_queue_segment_boundary(rq, PAGE_SIZE - 1); 441 blk_queue_max_segment_size(rq, PAGE_SIZE); 442 443 /* Ensure a merged request will fit in a single I/O ring slot. */ 444 blk_queue_max_segments(rq, BLKIF_MAX_SEGMENTS_PER_REQUEST); 445 446 /* Make sure buffer addresses are sector-aligned. */ 447 blk_queue_dma_alignment(rq, 511); 448 449 /* Make sure we don't use bounce buffers. */ 450 blk_queue_bounce_limit(rq, BLK_BOUNCE_ANY); 451 452 gd->queue = rq; 453 454 return 0; 455 } 456 457 458 static void xlvbd_flush(struct blkfront_info *info) 459 { 460 blk_queue_flush(info->rq, info->feature_flush); 461 printk(KERN_INFO "blkfront: %s: %s: %s\n", 462 info->gd->disk_name, 463 info->flush_op == BLKIF_OP_WRITE_BARRIER ? 464 "barrier" : (info->flush_op == BLKIF_OP_FLUSH_DISKCACHE ? 465 "flush diskcache" : "barrier or flush"), 466 info->feature_flush ? "enabled" : "disabled"); 467 } 468 469 static int xen_translate_vdev(int vdevice, int *minor, unsigned int *offset) 470 { 471 int major; 472 major = BLKIF_MAJOR(vdevice); 473 *minor = BLKIF_MINOR(vdevice); 474 switch (major) { 475 case XEN_IDE0_MAJOR: 476 *offset = (*minor / 64) + EMULATED_HD_DISK_NAME_OFFSET; 477 *minor = ((*minor / 64) * PARTS_PER_DISK) + 478 EMULATED_HD_DISK_MINOR_OFFSET; 479 break; 480 case XEN_IDE1_MAJOR: 481 *offset = (*minor / 64) + 2 + EMULATED_HD_DISK_NAME_OFFSET; 482 *minor = (((*minor / 64) + 2) * PARTS_PER_DISK) + 483 EMULATED_HD_DISK_MINOR_OFFSET; 484 break; 485 case XEN_SCSI_DISK0_MAJOR: 486 *offset = (*minor / PARTS_PER_DISK) + EMULATED_SD_DISK_NAME_OFFSET; 487 *minor = *minor + EMULATED_SD_DISK_MINOR_OFFSET; 488 break; 489 case XEN_SCSI_DISK1_MAJOR: 490 case XEN_SCSI_DISK2_MAJOR: 491 case XEN_SCSI_DISK3_MAJOR: 492 case XEN_SCSI_DISK4_MAJOR: 493 case XEN_SCSI_DISK5_MAJOR: 494 case XEN_SCSI_DISK6_MAJOR: 495 case XEN_SCSI_DISK7_MAJOR: 496 *offset = (*minor / PARTS_PER_DISK) + 497 ((major - XEN_SCSI_DISK1_MAJOR + 1) * 16) + 498 EMULATED_SD_DISK_NAME_OFFSET; 499 *minor = *minor + 500 ((major - XEN_SCSI_DISK1_MAJOR + 1) * 16 * PARTS_PER_DISK) + 501 EMULATED_SD_DISK_MINOR_OFFSET; 502 break; 503 case XEN_SCSI_DISK8_MAJOR: 504 case XEN_SCSI_DISK9_MAJOR: 505 case XEN_SCSI_DISK10_MAJOR: 506 case XEN_SCSI_DISK11_MAJOR: 507 case XEN_SCSI_DISK12_MAJOR: 508 case XEN_SCSI_DISK13_MAJOR: 509 case XEN_SCSI_DISK14_MAJOR: 510 case XEN_SCSI_DISK15_MAJOR: 511 *offset = (*minor / PARTS_PER_DISK) + 512 ((major - XEN_SCSI_DISK8_MAJOR + 8) * 16) + 513 EMULATED_SD_DISK_NAME_OFFSET; 514 *minor = *minor + 515 ((major - XEN_SCSI_DISK8_MAJOR + 8) * 16 * PARTS_PER_DISK) + 516 EMULATED_SD_DISK_MINOR_OFFSET; 517 break; 518 case XENVBD_MAJOR: 519 *offset = *minor / PARTS_PER_DISK; 520 break; 521 default: 522 printk(KERN_WARNING "blkfront: your disk configuration is " 523 "incorrect, please use an xvd device instead\n"); 524 return -ENODEV; 525 } 526 return 0; 527 } 528 529 static int xlvbd_alloc_gendisk(blkif_sector_t capacity, 530 struct blkfront_info *info, 531 u16 vdisk_info, u16 sector_size) 532 { 533 struct gendisk *gd; 534 int nr_minors = 1; 535 int err; 536 unsigned int offset; 537 int minor; 538 int nr_parts; 539 540 BUG_ON(info->gd != NULL); 541 BUG_ON(info->rq != NULL); 542 543 if ((info->vdevice>>EXT_SHIFT) > 1) { 544 /* this is above the extended range; something is wrong */ 545 printk(KERN_WARNING "blkfront: vdevice 0x%x is above the extended range; ignoring\n", info->vdevice); 546 return -ENODEV; 547 } 548 549 if (!VDEV_IS_EXTENDED(info->vdevice)) { 550 err = xen_translate_vdev(info->vdevice, &minor, &offset); 551 if (err) 552 return err; 553 nr_parts = PARTS_PER_DISK; 554 } else { 555 minor = BLKIF_MINOR_EXT(info->vdevice); 556 nr_parts = PARTS_PER_EXT_DISK; 557 offset = minor / nr_parts; 558 if (xen_hvm_domain() && offset < EMULATED_HD_DISK_NAME_OFFSET + 4) 559 printk(KERN_WARNING "blkfront: vdevice 0x%x might conflict with " 560 "emulated IDE disks,\n\t choose an xvd device name" 561 "from xvde on\n", info->vdevice); 562 } 563 err = -ENODEV; 564 565 if ((minor % nr_parts) == 0) 566 nr_minors = nr_parts; 567 568 err = xlbd_reserve_minors(minor, nr_minors); 569 if (err) 570 goto out; 571 err = -ENODEV; 572 573 gd = alloc_disk(nr_minors); 574 if (gd == NULL) 575 goto release; 576 577 if (nr_minors > 1) { 578 if (offset < 26) 579 sprintf(gd->disk_name, "%s%c", DEV_NAME, 'a' + offset); 580 else 581 sprintf(gd->disk_name, "%s%c%c", DEV_NAME, 582 'a' + ((offset / 26)-1), 'a' + (offset % 26)); 583 } else { 584 if (offset < 26) 585 sprintf(gd->disk_name, "%s%c%d", DEV_NAME, 586 'a' + offset, 587 minor & (nr_parts - 1)); 588 else 589 sprintf(gd->disk_name, "%s%c%c%d", DEV_NAME, 590 'a' + ((offset / 26) - 1), 591 'a' + (offset % 26), 592 minor & (nr_parts - 1)); 593 } 594 595 gd->major = XENVBD_MAJOR; 596 gd->first_minor = minor; 597 gd->fops = &xlvbd_block_fops; 598 gd->private_data = info; 599 gd->driverfs_dev = &(info->xbdev->dev); 600 set_capacity(gd, capacity); 601 602 if (xlvbd_init_blk_queue(gd, sector_size)) { 603 del_gendisk(gd); 604 goto release; 605 } 606 607 info->rq = gd->queue; 608 info->gd = gd; 609 610 xlvbd_flush(info); 611 612 if (vdisk_info & VDISK_READONLY) 613 set_disk_ro(gd, 1); 614 615 if (vdisk_info & VDISK_REMOVABLE) 616 gd->flags |= GENHD_FL_REMOVABLE; 617 618 if (vdisk_info & VDISK_CDROM) 619 gd->flags |= GENHD_FL_CD; 620 621 return 0; 622 623 release: 624 xlbd_release_minors(minor, nr_minors); 625 out: 626 return err; 627 } 628 629 static void xlvbd_release_gendisk(struct blkfront_info *info) 630 { 631 unsigned int minor, nr_minors; 632 unsigned long flags; 633 634 if (info->rq == NULL) 635 return; 636 637 spin_lock_irqsave(&info->io_lock, flags); 638 639 /* No more blkif_request(). */ 640 blk_stop_queue(info->rq); 641 642 /* No more gnttab callback work. */ 643 gnttab_cancel_free_callback(&info->callback); 644 spin_unlock_irqrestore(&info->io_lock, flags); 645 646 /* Flush gnttab callback work. Must be done with no locks held. */ 647 flush_work_sync(&info->work); 648 649 del_gendisk(info->gd); 650 651 minor = info->gd->first_minor; 652 nr_minors = info->gd->minors; 653 xlbd_release_minors(minor, nr_minors); 654 655 blk_cleanup_queue(info->rq); 656 info->rq = NULL; 657 658 put_disk(info->gd); 659 info->gd = NULL; 660 } 661 662 static void kick_pending_request_queues(struct blkfront_info *info) 663 { 664 if (!RING_FULL(&info->ring)) { 665 /* Re-enable calldowns. */ 666 blk_start_queue(info->rq); 667 /* Kick things off immediately. */ 668 do_blkif_request(info->rq); 669 } 670 } 671 672 static void blkif_restart_queue(struct work_struct *work) 673 { 674 struct blkfront_info *info = container_of(work, struct blkfront_info, work); 675 676 spin_lock_irq(&info->io_lock); 677 if (info->connected == BLKIF_STATE_CONNECTED) 678 kick_pending_request_queues(info); 679 spin_unlock_irq(&info->io_lock); 680 } 681 682 static void blkif_free(struct blkfront_info *info, int suspend) 683 { 684 /* Prevent new requests being issued until we fix things up. */ 685 spin_lock_irq(&info->io_lock); 686 info->connected = suspend ? 687 BLKIF_STATE_SUSPENDED : BLKIF_STATE_DISCONNECTED; 688 /* No more blkif_request(). */ 689 if (info->rq) 690 blk_stop_queue(info->rq); 691 /* No more gnttab callback work. */ 692 gnttab_cancel_free_callback(&info->callback); 693 spin_unlock_irq(&info->io_lock); 694 695 /* Flush gnttab callback work. Must be done with no locks held. */ 696 flush_work_sync(&info->work); 697 698 /* Free resources associated with old device channel. */ 699 if (info->ring_ref != GRANT_INVALID_REF) { 700 gnttab_end_foreign_access(info->ring_ref, 0, 701 (unsigned long)info->ring.sring); 702 info->ring_ref = GRANT_INVALID_REF; 703 info->ring.sring = NULL; 704 } 705 if (info->irq) 706 unbind_from_irqhandler(info->irq, info); 707 info->evtchn = info->irq = 0; 708 709 } 710 711 static void blkif_completion(struct blk_shadow *s) 712 { 713 int i; 714 /* Do not let BLKIF_OP_DISCARD as nr_segment is in the same place 715 * flag. */ 716 for (i = 0; i < s->req.u.rw.nr_segments; i++) 717 gnttab_end_foreign_access(s->req.u.rw.seg[i].gref, 0, 0UL); 718 } 719 720 static irqreturn_t blkif_interrupt(int irq, void *dev_id) 721 { 722 struct request *req; 723 struct blkif_response *bret; 724 RING_IDX i, rp; 725 unsigned long flags; 726 struct blkfront_info *info = (struct blkfront_info *)dev_id; 727 int error; 728 729 spin_lock_irqsave(&info->io_lock, flags); 730 731 if (unlikely(info->connected != BLKIF_STATE_CONNECTED)) { 732 spin_unlock_irqrestore(&info->io_lock, flags); 733 return IRQ_HANDLED; 734 } 735 736 again: 737 rp = info->ring.sring->rsp_prod; 738 rmb(); /* Ensure we see queued responses up to 'rp'. */ 739 740 for (i = info->ring.rsp_cons; i != rp; i++) { 741 unsigned long id; 742 743 bret = RING_GET_RESPONSE(&info->ring, i); 744 id = bret->id; 745 req = info->shadow[id].request; 746 747 if (bret->operation != BLKIF_OP_DISCARD) 748 blkif_completion(&info->shadow[id]); 749 750 add_id_to_freelist(info, id); 751 752 error = (bret->status == BLKIF_RSP_OKAY) ? 0 : -EIO; 753 switch (bret->operation) { 754 case BLKIF_OP_DISCARD: 755 if (unlikely(bret->status == BLKIF_RSP_EOPNOTSUPP)) { 756 struct request_queue *rq = info->rq; 757 printk(KERN_WARNING "blkfront: %s: discard op failed\n", 758 info->gd->disk_name); 759 error = -EOPNOTSUPP; 760 info->feature_discard = 0; 761 info->feature_secdiscard = 0; 762 queue_flag_clear(QUEUE_FLAG_DISCARD, rq); 763 queue_flag_clear(QUEUE_FLAG_SECDISCARD, rq); 764 } 765 __blk_end_request_all(req, error); 766 break; 767 case BLKIF_OP_FLUSH_DISKCACHE: 768 case BLKIF_OP_WRITE_BARRIER: 769 if (unlikely(bret->status == BLKIF_RSP_EOPNOTSUPP)) { 770 printk(KERN_WARNING "blkfront: %s: write %s op failed\n", 771 info->flush_op == BLKIF_OP_WRITE_BARRIER ? 772 "barrier" : "flush disk cache", 773 info->gd->disk_name); 774 error = -EOPNOTSUPP; 775 } 776 if (unlikely(bret->status == BLKIF_RSP_ERROR && 777 info->shadow[id].req.u.rw.nr_segments == 0)) { 778 printk(KERN_WARNING "blkfront: %s: empty write %s op failed\n", 779 info->flush_op == BLKIF_OP_WRITE_BARRIER ? 780 "barrier" : "flush disk cache", 781 info->gd->disk_name); 782 error = -EOPNOTSUPP; 783 } 784 if (unlikely(error)) { 785 if (error == -EOPNOTSUPP) 786 error = 0; 787 info->feature_flush = 0; 788 info->flush_op = 0; 789 xlvbd_flush(info); 790 } 791 /* fall through */ 792 case BLKIF_OP_READ: 793 case BLKIF_OP_WRITE: 794 if (unlikely(bret->status != BLKIF_RSP_OKAY)) 795 dev_dbg(&info->xbdev->dev, "Bad return from blkdev data " 796 "request: %x\n", bret->status); 797 798 __blk_end_request_all(req, error); 799 break; 800 default: 801 BUG(); 802 } 803 } 804 805 info->ring.rsp_cons = i; 806 807 if (i != info->ring.req_prod_pvt) { 808 int more_to_do; 809 RING_FINAL_CHECK_FOR_RESPONSES(&info->ring, more_to_do); 810 if (more_to_do) 811 goto again; 812 } else 813 info->ring.sring->rsp_event = i + 1; 814 815 kick_pending_request_queues(info); 816 817 spin_unlock_irqrestore(&info->io_lock, flags); 818 819 return IRQ_HANDLED; 820 } 821 822 823 static int setup_blkring(struct xenbus_device *dev, 824 struct blkfront_info *info) 825 { 826 struct blkif_sring *sring; 827 int err; 828 829 info->ring_ref = GRANT_INVALID_REF; 830 831 sring = (struct blkif_sring *)__get_free_page(GFP_NOIO | __GFP_HIGH); 832 if (!sring) { 833 xenbus_dev_fatal(dev, -ENOMEM, "allocating shared ring"); 834 return -ENOMEM; 835 } 836 SHARED_RING_INIT(sring); 837 FRONT_RING_INIT(&info->ring, sring, PAGE_SIZE); 838 839 sg_init_table(info->sg, BLKIF_MAX_SEGMENTS_PER_REQUEST); 840 841 err = xenbus_grant_ring(dev, virt_to_mfn(info->ring.sring)); 842 if (err < 0) { 843 free_page((unsigned long)sring); 844 info->ring.sring = NULL; 845 goto fail; 846 } 847 info->ring_ref = err; 848 849 err = xenbus_alloc_evtchn(dev, &info->evtchn); 850 if (err) 851 goto fail; 852 853 err = bind_evtchn_to_irqhandler(info->evtchn, 854 blkif_interrupt, 855 IRQF_SAMPLE_RANDOM, "blkif", info); 856 if (err <= 0) { 857 xenbus_dev_fatal(dev, err, 858 "bind_evtchn_to_irqhandler failed"); 859 goto fail; 860 } 861 info->irq = err; 862 863 return 0; 864 fail: 865 blkif_free(info, 0); 866 return err; 867 } 868 869 870 /* Common code used when first setting up, and when resuming. */ 871 static int talk_to_blkback(struct xenbus_device *dev, 872 struct blkfront_info *info) 873 { 874 const char *message = NULL; 875 struct xenbus_transaction xbt; 876 int err; 877 878 /* Create shared ring, alloc event channel. */ 879 err = setup_blkring(dev, info); 880 if (err) 881 goto out; 882 883 again: 884 err = xenbus_transaction_start(&xbt); 885 if (err) { 886 xenbus_dev_fatal(dev, err, "starting transaction"); 887 goto destroy_blkring; 888 } 889 890 err = xenbus_printf(xbt, dev->nodename, 891 "ring-ref", "%u", info->ring_ref); 892 if (err) { 893 message = "writing ring-ref"; 894 goto abort_transaction; 895 } 896 err = xenbus_printf(xbt, dev->nodename, 897 "event-channel", "%u", info->evtchn); 898 if (err) { 899 message = "writing event-channel"; 900 goto abort_transaction; 901 } 902 err = xenbus_printf(xbt, dev->nodename, "protocol", "%s", 903 XEN_IO_PROTO_ABI_NATIVE); 904 if (err) { 905 message = "writing protocol"; 906 goto abort_transaction; 907 } 908 909 err = xenbus_transaction_end(xbt, 0); 910 if (err) { 911 if (err == -EAGAIN) 912 goto again; 913 xenbus_dev_fatal(dev, err, "completing transaction"); 914 goto destroy_blkring; 915 } 916 917 xenbus_switch_state(dev, XenbusStateInitialised); 918 919 return 0; 920 921 abort_transaction: 922 xenbus_transaction_end(xbt, 1); 923 if (message) 924 xenbus_dev_fatal(dev, err, "%s", message); 925 destroy_blkring: 926 blkif_free(info, 0); 927 out: 928 return err; 929 } 930 931 /** 932 * Entry point to this code when a new device is created. Allocate the basic 933 * structures and the ring buffer for communication with the backend, and 934 * inform the backend of the appropriate details for those. Switch to 935 * Initialised state. 936 */ 937 static int blkfront_probe(struct xenbus_device *dev, 938 const struct xenbus_device_id *id) 939 { 940 int err, vdevice, i; 941 struct blkfront_info *info; 942 943 /* FIXME: Use dynamic device id if this is not set. */ 944 err = xenbus_scanf(XBT_NIL, dev->nodename, 945 "virtual-device", "%i", &vdevice); 946 if (err != 1) { 947 /* go looking in the extended area instead */ 948 err = xenbus_scanf(XBT_NIL, dev->nodename, "virtual-device-ext", 949 "%i", &vdevice); 950 if (err != 1) { 951 xenbus_dev_fatal(dev, err, "reading virtual-device"); 952 return err; 953 } 954 } 955 956 if (xen_hvm_domain()) { 957 char *type; 958 int len; 959 /* no unplug has been done: do not hook devices != xen vbds */ 960 if (xen_platform_pci_unplug & XEN_UNPLUG_UNNECESSARY) { 961 int major; 962 963 if (!VDEV_IS_EXTENDED(vdevice)) 964 major = BLKIF_MAJOR(vdevice); 965 else 966 major = XENVBD_MAJOR; 967 968 if (major != XENVBD_MAJOR) { 969 printk(KERN_INFO 970 "%s: HVM does not support vbd %d as xen block device\n", 971 __FUNCTION__, vdevice); 972 return -ENODEV; 973 } 974 } 975 /* do not create a PV cdrom device if we are an HVM guest */ 976 type = xenbus_read(XBT_NIL, dev->nodename, "device-type", &len); 977 if (IS_ERR(type)) 978 return -ENODEV; 979 if (strncmp(type, "cdrom", 5) == 0) { 980 kfree(type); 981 return -ENODEV; 982 } 983 kfree(type); 984 } 985 info = kzalloc(sizeof(*info), GFP_KERNEL); 986 if (!info) { 987 xenbus_dev_fatal(dev, -ENOMEM, "allocating info structure"); 988 return -ENOMEM; 989 } 990 991 mutex_init(&info->mutex); 992 spin_lock_init(&info->io_lock); 993 info->xbdev = dev; 994 info->vdevice = vdevice; 995 info->connected = BLKIF_STATE_DISCONNECTED; 996 INIT_WORK(&info->work, blkif_restart_queue); 997 998 for (i = 0; i < BLK_RING_SIZE; i++) 999 info->shadow[i].req.u.rw.id = i+1; 1000 info->shadow[BLK_RING_SIZE-1].req.u.rw.id = 0x0fffffff; 1001 1002 /* Front end dir is a number, which is used as the id. */ 1003 info->handle = simple_strtoul(strrchr(dev->nodename, '/')+1, NULL, 0); 1004 dev_set_drvdata(&dev->dev, info); 1005 1006 err = talk_to_blkback(dev, info); 1007 if (err) { 1008 kfree(info); 1009 dev_set_drvdata(&dev->dev, NULL); 1010 return err; 1011 } 1012 1013 return 0; 1014 } 1015 1016 1017 static int blkif_recover(struct blkfront_info *info) 1018 { 1019 int i; 1020 struct blkif_request *req; 1021 struct blk_shadow *copy; 1022 int j; 1023 1024 /* Stage 1: Make a safe copy of the shadow state. */ 1025 copy = kmalloc(sizeof(info->shadow), 1026 GFP_NOIO | __GFP_REPEAT | __GFP_HIGH); 1027 if (!copy) 1028 return -ENOMEM; 1029 memcpy(copy, info->shadow, sizeof(info->shadow)); 1030 1031 /* Stage 2: Set up free list. */ 1032 memset(&info->shadow, 0, sizeof(info->shadow)); 1033 for (i = 0; i < BLK_RING_SIZE; i++) 1034 info->shadow[i].req.u.rw.id = i+1; 1035 info->shadow_free = info->ring.req_prod_pvt; 1036 info->shadow[BLK_RING_SIZE-1].req.u.rw.id = 0x0fffffff; 1037 1038 /* Stage 3: Find pending requests and requeue them. */ 1039 for (i = 0; i < BLK_RING_SIZE; i++) { 1040 /* Not in use? */ 1041 if (!copy[i].request) 1042 continue; 1043 1044 /* Grab a request slot and copy shadow state into it. */ 1045 req = RING_GET_REQUEST(&info->ring, info->ring.req_prod_pvt); 1046 *req = copy[i].req; 1047 1048 /* We get a new request id, and must reset the shadow state. */ 1049 req->u.rw.id = get_id_from_freelist(info); 1050 memcpy(&info->shadow[req->u.rw.id], ©[i], sizeof(copy[i])); 1051 1052 if (req->operation != BLKIF_OP_DISCARD) { 1053 /* Rewrite any grant references invalidated by susp/resume. */ 1054 for (j = 0; j < req->u.rw.nr_segments; j++) 1055 gnttab_grant_foreign_access_ref( 1056 req->u.rw.seg[j].gref, 1057 info->xbdev->otherend_id, 1058 pfn_to_mfn(info->shadow[req->u.rw.id].frame[j]), 1059 rq_data_dir(info->shadow[req->u.rw.id].request)); 1060 } 1061 info->shadow[req->u.rw.id].req = *req; 1062 1063 info->ring.req_prod_pvt++; 1064 } 1065 1066 kfree(copy); 1067 1068 xenbus_switch_state(info->xbdev, XenbusStateConnected); 1069 1070 spin_lock_irq(&info->io_lock); 1071 1072 /* Now safe for us to use the shared ring */ 1073 info->connected = BLKIF_STATE_CONNECTED; 1074 1075 /* Send off requeued requests */ 1076 flush_requests(info); 1077 1078 /* Kick any other new requests queued since we resumed */ 1079 kick_pending_request_queues(info); 1080 1081 spin_unlock_irq(&info->io_lock); 1082 1083 return 0; 1084 } 1085 1086 /** 1087 * We are reconnecting to the backend, due to a suspend/resume, or a backend 1088 * driver restart. We tear down our blkif structure and recreate it, but 1089 * leave the device-layer structures intact so that this is transparent to the 1090 * rest of the kernel. 1091 */ 1092 static int blkfront_resume(struct xenbus_device *dev) 1093 { 1094 struct blkfront_info *info = dev_get_drvdata(&dev->dev); 1095 int err; 1096 1097 dev_dbg(&dev->dev, "blkfront_resume: %s\n", dev->nodename); 1098 1099 blkif_free(info, info->connected == BLKIF_STATE_CONNECTED); 1100 1101 err = talk_to_blkback(dev, info); 1102 if (info->connected == BLKIF_STATE_SUSPENDED && !err) 1103 err = blkif_recover(info); 1104 1105 return err; 1106 } 1107 1108 static void 1109 blkfront_closing(struct blkfront_info *info) 1110 { 1111 struct xenbus_device *xbdev = info->xbdev; 1112 struct block_device *bdev = NULL; 1113 1114 mutex_lock(&info->mutex); 1115 1116 if (xbdev->state == XenbusStateClosing) { 1117 mutex_unlock(&info->mutex); 1118 return; 1119 } 1120 1121 if (info->gd) 1122 bdev = bdget_disk(info->gd, 0); 1123 1124 mutex_unlock(&info->mutex); 1125 1126 if (!bdev) { 1127 xenbus_frontend_closed(xbdev); 1128 return; 1129 } 1130 1131 mutex_lock(&bdev->bd_mutex); 1132 1133 if (bdev->bd_openers) { 1134 xenbus_dev_error(xbdev, -EBUSY, 1135 "Device in use; refusing to close"); 1136 xenbus_switch_state(xbdev, XenbusStateClosing); 1137 } else { 1138 xlvbd_release_gendisk(info); 1139 xenbus_frontend_closed(xbdev); 1140 } 1141 1142 mutex_unlock(&bdev->bd_mutex); 1143 bdput(bdev); 1144 } 1145 1146 static void blkfront_setup_discard(struct blkfront_info *info) 1147 { 1148 int err; 1149 char *type; 1150 unsigned int discard_granularity; 1151 unsigned int discard_alignment; 1152 unsigned int discard_secure; 1153 1154 type = xenbus_read(XBT_NIL, info->xbdev->otherend, "type", NULL); 1155 if (IS_ERR(type)) 1156 return; 1157 1158 info->feature_secdiscard = 0; 1159 if (strncmp(type, "phy", 3) == 0) { 1160 err = xenbus_gather(XBT_NIL, info->xbdev->otherend, 1161 "discard-granularity", "%u", &discard_granularity, 1162 "discard-alignment", "%u", &discard_alignment, 1163 NULL); 1164 if (!err) { 1165 info->feature_discard = 1; 1166 info->discard_granularity = discard_granularity; 1167 info->discard_alignment = discard_alignment; 1168 } 1169 err = xenbus_gather(XBT_NIL, info->xbdev->otherend, 1170 "discard-secure", "%d", &discard_secure, 1171 NULL); 1172 if (!err) 1173 info->feature_secdiscard = discard_secure; 1174 1175 } else if (strncmp(type, "file", 4) == 0) 1176 info->feature_discard = 1; 1177 1178 kfree(type); 1179 } 1180 1181 /* 1182 * Invoked when the backend is finally 'ready' (and has told produced 1183 * the details about the physical device - #sectors, size, etc). 1184 */ 1185 static void blkfront_connect(struct blkfront_info *info) 1186 { 1187 unsigned long long sectors; 1188 unsigned long sector_size; 1189 unsigned int binfo; 1190 int err; 1191 int barrier, flush, discard; 1192 1193 switch (info->connected) { 1194 case BLKIF_STATE_CONNECTED: 1195 /* 1196 * Potentially, the back-end may be signalling 1197 * a capacity change; update the capacity. 1198 */ 1199 err = xenbus_scanf(XBT_NIL, info->xbdev->otherend, 1200 "sectors", "%Lu", §ors); 1201 if (XENBUS_EXIST_ERR(err)) 1202 return; 1203 printk(KERN_INFO "Setting capacity to %Lu\n", 1204 sectors); 1205 set_capacity(info->gd, sectors); 1206 revalidate_disk(info->gd); 1207 1208 /* fall through */ 1209 case BLKIF_STATE_SUSPENDED: 1210 return; 1211 1212 default: 1213 break; 1214 } 1215 1216 dev_dbg(&info->xbdev->dev, "%s:%s.\n", 1217 __func__, info->xbdev->otherend); 1218 1219 err = xenbus_gather(XBT_NIL, info->xbdev->otherend, 1220 "sectors", "%llu", §ors, 1221 "info", "%u", &binfo, 1222 "sector-size", "%lu", §or_size, 1223 NULL); 1224 if (err) { 1225 xenbus_dev_fatal(info->xbdev, err, 1226 "reading backend fields at %s", 1227 info->xbdev->otherend); 1228 return; 1229 } 1230 1231 info->feature_flush = 0; 1232 info->flush_op = 0; 1233 1234 err = xenbus_gather(XBT_NIL, info->xbdev->otherend, 1235 "feature-barrier", "%d", &barrier, 1236 NULL); 1237 1238 /* 1239 * If there's no "feature-barrier" defined, then it means 1240 * we're dealing with a very old backend which writes 1241 * synchronously; nothing to do. 1242 * 1243 * If there are barriers, then we use flush. 1244 */ 1245 if (!err && barrier) { 1246 info->feature_flush = REQ_FLUSH | REQ_FUA; 1247 info->flush_op = BLKIF_OP_WRITE_BARRIER; 1248 } 1249 /* 1250 * And if there is "feature-flush-cache" use that above 1251 * barriers. 1252 */ 1253 err = xenbus_gather(XBT_NIL, info->xbdev->otherend, 1254 "feature-flush-cache", "%d", &flush, 1255 NULL); 1256 1257 if (!err && flush) { 1258 info->feature_flush = REQ_FLUSH; 1259 info->flush_op = BLKIF_OP_FLUSH_DISKCACHE; 1260 } 1261 1262 err = xenbus_gather(XBT_NIL, info->xbdev->otherend, 1263 "feature-discard", "%d", &discard, 1264 NULL); 1265 1266 if (!err && discard) 1267 blkfront_setup_discard(info); 1268 1269 err = xlvbd_alloc_gendisk(sectors, info, binfo, sector_size); 1270 if (err) { 1271 xenbus_dev_fatal(info->xbdev, err, "xlvbd_add at %s", 1272 info->xbdev->otherend); 1273 return; 1274 } 1275 1276 xenbus_switch_state(info->xbdev, XenbusStateConnected); 1277 1278 /* Kick pending requests. */ 1279 spin_lock_irq(&info->io_lock); 1280 info->connected = BLKIF_STATE_CONNECTED; 1281 kick_pending_request_queues(info); 1282 spin_unlock_irq(&info->io_lock); 1283 1284 add_disk(info->gd); 1285 1286 info->is_ready = 1; 1287 } 1288 1289 /** 1290 * Callback received when the backend's state changes. 1291 */ 1292 static void blkback_changed(struct xenbus_device *dev, 1293 enum xenbus_state backend_state) 1294 { 1295 struct blkfront_info *info = dev_get_drvdata(&dev->dev); 1296 1297 dev_dbg(&dev->dev, "blkfront:blkback_changed to state %d.\n", backend_state); 1298 1299 switch (backend_state) { 1300 case XenbusStateInitialising: 1301 case XenbusStateInitWait: 1302 case XenbusStateInitialised: 1303 case XenbusStateReconfiguring: 1304 case XenbusStateReconfigured: 1305 case XenbusStateUnknown: 1306 case XenbusStateClosed: 1307 break; 1308 1309 case XenbusStateConnected: 1310 blkfront_connect(info); 1311 break; 1312 1313 case XenbusStateClosing: 1314 blkfront_closing(info); 1315 break; 1316 } 1317 } 1318 1319 static int blkfront_remove(struct xenbus_device *xbdev) 1320 { 1321 struct blkfront_info *info = dev_get_drvdata(&xbdev->dev); 1322 struct block_device *bdev = NULL; 1323 struct gendisk *disk; 1324 1325 dev_dbg(&xbdev->dev, "%s removed", xbdev->nodename); 1326 1327 blkif_free(info, 0); 1328 1329 mutex_lock(&info->mutex); 1330 1331 disk = info->gd; 1332 if (disk) 1333 bdev = bdget_disk(disk, 0); 1334 1335 info->xbdev = NULL; 1336 mutex_unlock(&info->mutex); 1337 1338 if (!bdev) { 1339 kfree(info); 1340 return 0; 1341 } 1342 1343 /* 1344 * The xbdev was removed before we reached the Closed 1345 * state. See if it's safe to remove the disk. If the bdev 1346 * isn't closed yet, we let release take care of it. 1347 */ 1348 1349 mutex_lock(&bdev->bd_mutex); 1350 info = disk->private_data; 1351 1352 dev_warn(disk_to_dev(disk), 1353 "%s was hot-unplugged, %d stale handles\n", 1354 xbdev->nodename, bdev->bd_openers); 1355 1356 if (info && !bdev->bd_openers) { 1357 xlvbd_release_gendisk(info); 1358 disk->private_data = NULL; 1359 kfree(info); 1360 } 1361 1362 mutex_unlock(&bdev->bd_mutex); 1363 bdput(bdev); 1364 1365 return 0; 1366 } 1367 1368 static int blkfront_is_ready(struct xenbus_device *dev) 1369 { 1370 struct blkfront_info *info = dev_get_drvdata(&dev->dev); 1371 1372 return info->is_ready && info->xbdev; 1373 } 1374 1375 static int blkif_open(struct block_device *bdev, fmode_t mode) 1376 { 1377 struct gendisk *disk = bdev->bd_disk; 1378 struct blkfront_info *info; 1379 int err = 0; 1380 1381 mutex_lock(&blkfront_mutex); 1382 1383 info = disk->private_data; 1384 if (!info) { 1385 /* xbdev gone */ 1386 err = -ERESTARTSYS; 1387 goto out; 1388 } 1389 1390 mutex_lock(&info->mutex); 1391 1392 if (!info->gd) 1393 /* xbdev is closed */ 1394 err = -ERESTARTSYS; 1395 1396 mutex_unlock(&info->mutex); 1397 1398 out: 1399 mutex_unlock(&blkfront_mutex); 1400 return err; 1401 } 1402 1403 static int blkif_release(struct gendisk *disk, fmode_t mode) 1404 { 1405 struct blkfront_info *info = disk->private_data; 1406 struct block_device *bdev; 1407 struct xenbus_device *xbdev; 1408 1409 mutex_lock(&blkfront_mutex); 1410 1411 bdev = bdget_disk(disk, 0); 1412 1413 if (bdev->bd_openers) 1414 goto out; 1415 1416 /* 1417 * Check if we have been instructed to close. We will have 1418 * deferred this request, because the bdev was still open. 1419 */ 1420 1421 mutex_lock(&info->mutex); 1422 xbdev = info->xbdev; 1423 1424 if (xbdev && xbdev->state == XenbusStateClosing) { 1425 /* pending switch to state closed */ 1426 dev_info(disk_to_dev(bdev->bd_disk), "releasing disk\n"); 1427 xlvbd_release_gendisk(info); 1428 xenbus_frontend_closed(info->xbdev); 1429 } 1430 1431 mutex_unlock(&info->mutex); 1432 1433 if (!xbdev) { 1434 /* sudden device removal */ 1435 dev_info(disk_to_dev(bdev->bd_disk), "releasing disk\n"); 1436 xlvbd_release_gendisk(info); 1437 disk->private_data = NULL; 1438 kfree(info); 1439 } 1440 1441 out: 1442 bdput(bdev); 1443 mutex_unlock(&blkfront_mutex); 1444 return 0; 1445 } 1446 1447 static const struct block_device_operations xlvbd_block_fops = 1448 { 1449 .owner = THIS_MODULE, 1450 .open = blkif_open, 1451 .release = blkif_release, 1452 .getgeo = blkif_getgeo, 1453 .ioctl = blkif_ioctl, 1454 }; 1455 1456 1457 static const struct xenbus_device_id blkfront_ids[] = { 1458 { "vbd" }, 1459 { "" } 1460 }; 1461 1462 static DEFINE_XENBUS_DRIVER(blkfront, , 1463 .probe = blkfront_probe, 1464 .remove = blkfront_remove, 1465 .resume = blkfront_resume, 1466 .otherend_changed = blkback_changed, 1467 .is_ready = blkfront_is_ready, 1468 ); 1469 1470 static int __init xlblk_init(void) 1471 { 1472 int ret; 1473 1474 if (!xen_domain()) 1475 return -ENODEV; 1476 1477 if (xen_hvm_domain() && !xen_platform_pci_unplug) 1478 return -ENODEV; 1479 1480 if (register_blkdev(XENVBD_MAJOR, DEV_NAME)) { 1481 printk(KERN_WARNING "xen_blk: can't get major %d with name %s\n", 1482 XENVBD_MAJOR, DEV_NAME); 1483 return -ENODEV; 1484 } 1485 1486 ret = xenbus_register_frontend(&blkfront_driver); 1487 if (ret) { 1488 unregister_blkdev(XENVBD_MAJOR, DEV_NAME); 1489 return ret; 1490 } 1491 1492 return 0; 1493 } 1494 module_init(xlblk_init); 1495 1496 1497 static void __exit xlblk_exit(void) 1498 { 1499 return xenbus_unregister_driver(&blkfront_driver); 1500 } 1501 module_exit(xlblk_exit); 1502 1503 MODULE_DESCRIPTION("Xen virtual block device frontend"); 1504 MODULE_LICENSE("GPL"); 1505 MODULE_ALIAS_BLOCKDEV_MAJOR(XENVBD_MAJOR); 1506 MODULE_ALIAS("xen:vbd"); 1507 MODULE_ALIAS("xenblk"); 1508