drivers/block/virtio_blk.c

   1 //#define DEBUG
   2 #include <linux/spinlock.h>
   3 #include <linux/slab.h>
   4 #include <linux/blkdev.h>
   5 #include <linux/hdreg.h>
   6 #include <linux/module.h>
   7 #include <linux/mutex.h>
   8 #include <linux/virtio.h>
   9 #include <linux/virtio_blk.h>
  10 #include <linux/scatterlist.h>
  11 #include <linux/string_helpers.h>
  12 #include <scsi/scsi_cmnd.h>
  13 #include <linux/idr.h>
  14
  15 #define PART_BITS 4
  16
  17 static int major;
  18 static DEFINE_IDA(vd_index_ida);
  19
  20 struct workqueue_struct *virtblk_wq;
  21
  22 struct virtio_blk
  23 {
  24         spinlock_t lock;
  25
  26         struct virtio_device *vdev;
  27         struct virtqueue *vq;
  28
  29         /* The disk structure for the kernel. */
  30         struct gendisk *disk;
  31
  32         mempool_t *pool;
  33
  34         /* Process context for config space updates */
  35         struct work_struct config_work;
  36
  37         /* Lock for config space updates */
  38         struct mutex config_lock;
  39
  40         /* enable config space updates */
  41         bool config_enable;
  42
  43         /* What host tells us, plus 2 for header & tailer. */
  44         unsigned int sg_elems;
  45
  46         /* Ida index - used to track minor number allocations. */
  47         int index;
  48
  49         /* Scatterlist: can be too big for stack. */
  50         struct scatterlist sg[/*sg_elems*/];
  51 };
  52
  53 struct virtblk_req
  54 {
  55         struct request *req;
  56         struct virtio_blk_outhdr out_hdr;
  57         struct virtio_scsi_inhdr in_hdr;
  58         u8 status;
  59 };
  60
  61 static void blk_done(struct virtqueue *vq)
  62 {
  63         struct virtio_blk *vblk = vq->vdev->priv;
  64         struct virtblk_req *vbr;
  65         unsigned int len;
  66         unsigned long flags;
  67
  68         spin_lock_irqsave(&vblk->lock, flags);
  69         while ((vbr = virtqueue_get_buf(vblk->vq, &len)) != NULL) {
  70                 int error;
  71
  72                 switch (vbr->status) {
  73                 case VIRTIO_BLK_S_OK:
  74                         error = 0;
  75                         break;
  76                 case VIRTIO_BLK_S_UNSUPP:
  77                         error = -ENOTTY;
  78                         break;
  79                 default:
  80                         error = -EIO;
  81                         break;
  82                 }
  83
  84                 switch (vbr->req->cmd_type) {
  85                 case REQ_TYPE_BLOCK_PC:
  86                         vbr->req->resid_len = vbr->in_hdr.residual;
  87                         vbr->req->sense_len = vbr->in_hdr.sense_len;
  88                         vbr->req->errors = vbr->in_hdr.errors;
  89                         break;
  90                 case REQ_TYPE_SPECIAL:
  91                         vbr->req->errors = (error != 0);
  92                         break;
  93                 default:
  94                         break;
  95                 }
  96
  97                 __blk_end_request_all(vbr->req, error);
  98                 mempool_free(vbr, vblk->pool);
  99         }
 100         /* In case queue is stopped waiting for more buffers. */
 101         blk_start_queue(vblk->disk->queue);
 102         spin_unlock_irqrestore(&vblk->lock, flags);
 103 }
 104
 105 static bool do_req(struct request_queue *q, struct virtio_blk *vblk,
 106                    struct request *req)
 107 {
 108         unsigned long num, out = 0, in = 0;
 109         struct virtblk_req *vbr;
 110
 111         vbr = mempool_alloc(vblk->pool, GFP_ATOMIC);
 112         if (!vbr)
 113                 /* When another request finishes we'll try again. */
 114                 return false;
 115
 116         vbr->req = req;
 117
 118         if (req->cmd_flags & REQ_FLUSH) {
 119                 vbr->out_hdr.type = VIRTIO_BLK_T_FLUSH;
 120                 vbr->out_hdr.sector = 0;
 121                 vbr->out_hdr.ioprio = req_get_ioprio(vbr->req);
 122         } else {
 123                 switch (req->cmd_type) {
 124                 case REQ_TYPE_FS:
 125                         vbr->out_hdr.type = 0;
 126                         vbr->out_hdr.sector = blk_rq_pos(vbr->req);
 127                         vbr->out_hdr.ioprio = req_get_ioprio(vbr->req);
 128                         break;
 129                 case REQ_TYPE_BLOCK_PC:
 130                         vbr->out_hdr.type = VIRTIO_BLK_T_SCSI_CMD;
 131                         vbr->out_hdr.sector = 0;
 132                         vbr->out_hdr.ioprio = req_get_ioprio(vbr->req);
 133                         break;
 134                 case REQ_TYPE_SPECIAL:
 135                         vbr->out_hdr.type = VIRTIO_BLK_T_GET_ID;
 136                         vbr->out_hdr.sector = 0;
 137                         vbr->out_hdr.ioprio = req_get_ioprio(vbr->req);
 138                         break;
 139                 default:
 140                         /* We don't put anything else in the queue. */
 141                         BUG();
 142                 }
 143         }
 144
 145         sg_set_buf(&vblk->sg[out++], &vbr->out_hdr, sizeof(vbr->out_hdr));
 146
 147         /*
 148          * If this is a packet command we need a couple of additional headers.
 149          * Behind the normal outhdr we put a segment with the scsi command
 150          * block, and before the normal inhdr we put the sense data and the
 151          * inhdr with additional status information before the normal inhdr.
 152          */
 153         if (vbr->req->cmd_type == REQ_TYPE_BLOCK_PC)
 154                 sg_set_buf(&vblk->sg[out++], vbr->req->cmd, vbr->req->cmd_len);
 155
 156         num = blk_rq_map_sg(q, vbr->req, vblk->sg + out);
 157
 158         if (vbr->req->cmd_type == REQ_TYPE_BLOCK_PC) {
 159                 sg_set_buf(&vblk->sg[num + out + in++], vbr->req->sense, SCSI_SENSE_BUFFERSIZE);
 160                 sg_set_buf(&vblk->sg[num + out + in++], &vbr->in_hdr,
 161                            sizeof(vbr->in_hdr));
 162         }
 163
 164         sg_set_buf(&vblk->sg[num + out + in++], &vbr->status,
 165                    sizeof(vbr->status));
 166
 167         if (num) {
 168                 if (rq_data_dir(vbr->req) == WRITE) {
 169                         vbr->out_hdr.type |= VIRTIO_BLK_T_OUT;
 170                         out += num;
 171                 } else {
 172                         vbr->out_hdr.type |= VIRTIO_BLK_T_IN;
 173                         in += num;
 174                 }
 175         }
 176
 177         if (virtqueue_add_buf(vblk->vq, vblk->sg, out, in, vbr, GFP_ATOMIC)<0) {
 178                 mempool_free(vbr, vblk->pool);
 179                 return false;
 180         }
 181
 182         return true;
 183 }
 184
 185 static void do_virtblk_request(struct request_queue *q)
 186 {
 187         struct virtio_blk *vblk = q->queuedata;
 188         struct request *req;
 189         unsigned int issued = 0;
 190
 191         while ((req = blk_peek_request(q)) != NULL) {
 192                 BUG_ON(req->nr_phys_segments + 2 > vblk->sg_elems);
 193
 194                 /* If this request fails, stop queue and wait for something to
 195                    finish to restart it. */
 196                 if (!do_req(q, vblk, req)) {
 197                         blk_stop_queue(q);
 198                         break;
 199                 }
 200                 blk_start_request(req);
 201                 issued++;
 202         }
 203
 204         if (issued)
 205                 virtqueue_kick(vblk->vq);
 206 }
 207
 208 /* return id (s/n) string for *disk to *id_str
 209  */
 210 static int virtblk_get_id(struct gendisk *disk, char *id_str)
 211 {
 212         struct virtio_blk *vblk = disk->private_data;
 213         struct request *req;
 214         struct bio *bio;
 215         int err;
 216
 217         bio = bio_map_kern(vblk->disk->queue, id_str, VIRTIO_BLK_ID_BYTES,
 218                            GFP_KERNEL);
 219         if (IS_ERR(bio))
 220                 return PTR_ERR(bio);
 221
 222         req = blk_make_request(vblk->disk->queue, bio, GFP_KERNEL);
 223         if (IS_ERR(req)) {
 224                 bio_put(bio);
 225                 return PTR_ERR(req);
 226         }
 227
 228         req->cmd_type = REQ_TYPE_SPECIAL;
 229         err = blk_execute_rq(vblk->disk->queue, vblk->disk, req, false);
 230         blk_put_request(req);
 231
 232         return err;
 233 }
 234
 235 static int virtblk_ioctl(struct block_device *bdev, fmode_t mode,
 236                              unsigned int cmd, unsigned long data)
 237 {
 238         struct gendisk *disk = bdev->bd_disk;
 239         struct virtio_blk *vblk = disk->private_data;
 240
 241         /*
 242          * Only allow the generic SCSI ioctls if the host can support it.
 243          */
 244         if (!virtio_has_feature(vblk->vdev, VIRTIO_BLK_F_SCSI))
 245                 return -ENOTTY;
 246
 247         return scsi_cmd_blk_ioctl(bdev, mode, cmd,
 248                                   (void __user *)data);
 249 }
 250
 251 /* We provide getgeo only to please some old bootloader/partitioning tools */
 252 static int virtblk_getgeo(struct block_device *bd, struct hd_geometry *geo)
 253 {
 254         struct virtio_blk *vblk = bd->bd_disk->private_data;
 255         struct virtio_blk_geometry vgeo;
 256         int err;
 257
 258         /* see if the host passed in geometry config */
 259         err = virtio_config_val(vblk->vdev, VIRTIO_BLK_F_GEOMETRY,
 260                                 offsetof(struct virtio_blk_config, geometry),
 261                                 &vgeo);
 262
 263         if (!err) {
 264                 geo->heads = vgeo.heads;
 265                 geo->sectors = vgeo.sectors;
 266                 geo->cylinders = vgeo.cylinders;
 267         } else {
 268                 /* some standard values, similar to sd */
 269                 geo->heads = 1 << 6;
 270                 geo->sectors = 1 << 5;
 271                 geo->cylinders = get_capacity(bd->bd_disk) >> 11;
 272         }
 273         return 0;
 274 }
 275
 276 static const struct block_device_operations virtblk_fops = {
 277         .ioctl  = virtblk_ioctl,
 278         .owner  = THIS_MODULE,
 279         .getgeo = virtblk_getgeo,
 280 };
 281
 282 static int index_to_minor(int index)
 283 {
 284         return index << PART_BITS;
 285 }
 286
 287 static int minor_to_index(int minor)
 288 {
 289         return minor >> PART_BITS;
 290 }
 291
 292 static ssize_t virtblk_serial_show(struct device *dev,
 293                                 struct device_attribute *attr, char *buf)
 294 {
 295         struct gendisk *disk = dev_to_disk(dev);
 296         int err;
 297
 298         /* sysfs gives us a PAGE_SIZE buffer */
 299         BUILD_BUG_ON(PAGE_SIZE < VIRTIO_BLK_ID_BYTES);
 300
 301         buf[VIRTIO_BLK_ID_BYTES] = '\0';
 302         err = virtblk_get_id(disk, buf);
 303         if (!err)
 304                 return strlen(buf);
 305
 306         if (err == -EIO) /* Unsupported? Make it empty. */
 307                 return 0;
 308
 309         return err;
 310 }
 311 DEVICE_ATTR(serial, S_IRUGO, virtblk_serial_show, NULL);
 312
 313 static void virtblk_config_changed_work(struct work_struct *work)
 314 {
 315         struct virtio_blk *vblk =
 316                 container_of(work, struct virtio_blk, config_work);
 317         struct virtio_device *vdev = vblk->vdev;
 318         struct request_queue *q = vblk->disk->queue;
 319         char cap_str_2[10], cap_str_10[10];
 320         u64 capacity, size;
 321
 322         mutex_lock(&vblk->config_lock);
 323         if (!vblk->config_enable)
 324                 goto done;
 325
 326         /* Host must always specify the capacity. */
 327         vdev->config->get(vdev, offsetof(struct virtio_blk_config, capacity),
 328                           &capacity, sizeof(capacity));
 329
 330         /* If capacity is too big, truncate with warning. */
 331         if ((sector_t)capacity != capacity) {
 332                 dev_warn(&vdev->dev, "Capacity %llu too large: truncating\n",
 333                          (unsigned long long)capacity);
 334                 capacity = (sector_t)-1;
 335         }
 336
 337         size = capacity * queue_logical_block_size(q);
 338         string_get_size(size, STRING_UNITS_2, cap_str_2, sizeof(cap_str_2));
 339         string_get_size(size, STRING_UNITS_10, cap_str_10, sizeof(cap_str_10));
 340
 341         dev_notice(&vdev->dev,
 342                   "new size: %llu %d-byte logical blocks (%s/%s)\n",
 343                   (unsigned long long)capacity,
 344                   queue_logical_block_size(q),
 345                   cap_str_10, cap_str_2);
 346
 347         set_capacity(vblk->disk, capacity);
 348         revalidate_disk(vblk->disk);
 349 done:
 350         mutex_unlock(&vblk->config_lock);
 351 }
 352
 353 static void virtblk_config_changed(struct virtio_device *vdev)
 354 {
 355         struct virtio_blk *vblk = vdev->priv;
 356
 357         queue_work(virtblk_wq, &vblk->config_work);
 358 }
 359
 360 static int init_vq(struct virtio_blk *vblk)
 361 {
 362         int err = 0;
 363
 364         /* We expect one virtqueue, for output. */
 365         vblk->vq = virtio_find_single_vq(vblk->vdev, blk_done, "requests");
 366         if (IS_ERR(vblk->vq))
 367                 err = PTR_ERR(vblk->vq);
 368
 369         return err;
 370 }
 371
 372 /*
 373  * Legacy naming scheme used for virtio devices.  We are stuck with it for
 374  * virtio blk but don't ever use it for any new driver.
 375  */
 376 static int virtblk_name_format(char *prefix, int index, char *buf, int buflen)
 377 {
 378         const int base = 'z' - 'a' + 1;
 379         char *begin = buf + strlen(prefix);
 380         char *end = buf + buflen;
 381         char *p;
 382         int unit;
 383
 384         p = end - 1;
 385         *p = '\0';
 386         unit = base;
 387         do {
 388                 if (p == begin)
 389                         return -EINVAL;
 390                 *--p = 'a' + (index % unit);
 391                 index = (index / unit) - 1;
 392         } while (index >= 0);
 393
 394         memmove(begin, p, end - p);
 395         memcpy(buf, prefix, strlen(prefix));
 396
 397         return 0;
 398 }
 399
 400 static int __devinit virtblk_probe(struct virtio_device *vdev)
 401 {
 402         struct virtio_blk *vblk;
 403         struct request_queue *q;
 404         int err, index;
 405         u64 cap;
 406         u32 v, blk_size, sg_elems, opt_io_size;
 407         u16 min_io_size;
 408         u8 physical_block_exp, alignment_offset;
 409
 410         err = ida_simple_get(&vd_index_ida, 0, minor_to_index(1 << MINORBITS),
 411                              GFP_KERNEL);
 412         if (err < 0)
 413                 goto out;
 414         index = err;
 415
 416         /* We need to know how many segments before we allocate. */
 417         err = virtio_config_val(vdev, VIRTIO_BLK_F_SEG_MAX,
 418                                 offsetof(struct virtio_blk_config, seg_max),
 419                                 &sg_elems);
 420
 421         /* We need at least one SG element, whatever they say. */
 422         if (err || !sg_elems)
 423                 sg_elems = 1;
 424
 425         /* We need an extra sg elements at head and tail. */
 426         sg_elems += 2;
 427         vdev->priv = vblk = kmalloc(sizeof(*vblk) +
 428                                     sizeof(vblk->sg[0]) * sg_elems, GFP_KERNEL);
 429         if (!vblk) {
 430                 err = -ENOMEM;
 431                 goto out_free_index;
 432         }
 433
 434         spin_lock_init(&vblk->lock);
 435         vblk->vdev = vdev;
 436         vblk->sg_elems = sg_elems;
 437         sg_init_table(vblk->sg, vblk->sg_elems);
 438         mutex_init(&vblk->config_lock);
 439         INIT_WORK(&vblk->config_work, virtblk_config_changed_work);
 440         vblk->config_enable = true;
 441
 442         err = init_vq(vblk);
 443         if (err)
 444                 goto out_free_vblk;
 445
 446         vblk->pool = mempool_create_kmalloc_pool(1,sizeof(struct virtblk_req));
 447         if (!vblk->pool) {
 448                 err = -ENOMEM;
 449                 goto out_free_vq;
 450         }
 451
 452         /* FIXME: How many partitions?  How long is a piece of string? */
 453         vblk->disk = alloc_disk(1 << PART_BITS);
 454         if (!vblk->disk) {
 455                 err = -ENOMEM;
 456                 goto out_mempool;
 457         }
 458
 459         q = vblk->disk->queue = blk_init_queue(do_virtblk_request, &vblk->lock);
 460         if (!q) {
 461                 err = -ENOMEM;
 462                 goto out_put_disk;
 463         }
 464
 465         q->queuedata = vblk;
 466
 467         virtblk_name_format("vd", index, vblk->disk->disk_name, DISK_NAME_LEN);
 468
 469         vblk->disk->major = major;
 470         vblk->disk->first_minor = index_to_minor(index);
 471         vblk->disk->private_data = vblk;
 472         vblk->disk->fops = &virtblk_fops;
 473         vblk->disk->driverfs_dev = &vdev->dev;
 474         vblk->index = index;
 475
 476         /* configure queue flush support */
 477         if (virtio_has_feature(vdev, VIRTIO_BLK_F_FLUSH))
 478                 blk_queue_flush(q, REQ_FLUSH);
 479
 480         /* If disk is read-only in the host, the guest should obey */
 481         if (virtio_has_feature(vdev, VIRTIO_BLK_F_RO))
 482                 set_disk_ro(vblk->disk, 1);
 483
 484         /* Host must always specify the capacity. */
 485         vdev->config->get(vdev, offsetof(struct virtio_blk_config, capacity),
 486                           &cap, sizeof(cap));
 487
 488         /* If capacity is too big, truncate with warning. */
 489         if ((sector_t)cap != cap) {
 490                 dev_warn(&vdev->dev, "Capacity %llu too large: truncating\n",
 491                          (unsigned long long)cap);
 492                 cap = (sector_t)-1;
 493         }
 494         set_capacity(vblk->disk, cap);
 495
 496         /* We can handle whatever the host told us to handle. */
 497         blk_queue_max_segments(q, vblk->sg_elems-2);
 498
 499         /* No need to bounce any requests */
 500         blk_queue_bounce_limit(q, BLK_BOUNCE_ANY);
 501
 502         /* No real sector limit. */
 503         blk_queue_max_hw_sectors(q, -1U);
 504
 505         /* Host can optionally specify maximum segment size and number of
 506          * segments. */
 507         err = virtio_config_val(vdev, VIRTIO_BLK_F_SIZE_MAX,
 508                                 offsetof(struct virtio_blk_config, size_max),
 509                                 &v);
 510         if (!err)
 511                 blk_queue_max_segment_size(q, v);
 512         else
 513                 blk_queue_max_segment_size(q, -1U);
 514
 515         /* Host can optionally specify the block size of the device */
 516         err = virtio_config_val(vdev, VIRTIO_BLK_F_BLK_SIZE,
 517                                 offsetof(struct virtio_blk_config, blk_size),
 518                                 &blk_size);
 519         if (!err)
 520                 blk_queue_logical_block_size(q, blk_size);
 521         else
 522                 blk_size = queue_logical_block_size(q);
 523
 524         /* Use topology information if available */
 525         err = virtio_config_val(vdev, VIRTIO_BLK_F_TOPOLOGY,
 526                         offsetof(struct virtio_blk_config, physical_block_exp),
 527                         &physical_block_exp);
 528         if (!err && physical_block_exp)
 529                 blk_queue_physical_block_size(q,
 530                                 blk_size * (1 << physical_block_exp));
 531
 532         err = virtio_config_val(vdev, VIRTIO_BLK_F_TOPOLOGY,
 533                         offsetof(struct virtio_blk_config, alignment_offset),
 534                         &alignment_offset);
 535         if (!err && alignment_offset)
 536                 blk_queue_alignment_offset(q, blk_size * alignment_offset);
 537
 538         err = virtio_config_val(vdev, VIRTIO_BLK_F_TOPOLOGY,
 539                         offsetof(struct virtio_blk_config, min_io_size),
 540                         &min_io_size);
 541         if (!err && min_io_size)
 542                 blk_queue_io_min(q, blk_size * min_io_size);
 543
 544         err = virtio_config_val(vdev, VIRTIO_BLK_F_TOPOLOGY,
 545                         offsetof(struct virtio_blk_config, opt_io_size),
 546                         &opt_io_size);
 547         if (!err && opt_io_size)
 548                 blk_queue_io_opt(q, blk_size * opt_io_size);
 549
 550
 551         add_disk(vblk->disk);
 552         err = device_create_file(disk_to_dev(vblk->disk), &dev_attr_serial);
 553         if (err)
 554                 goto out_del_disk;
 555
 556         return 0;
 557
 558 out_del_disk:
 559         del_gendisk(vblk->disk);
 560         blk_cleanup_queue(vblk->disk->queue);
 561 out_put_disk:
 562         put_disk(vblk->disk);
 563 out_mempool:
 564         mempool_destroy(vblk->pool);
 565 out_free_vq:
 566         vdev->config->del_vqs(vdev);
 567 out_free_vblk:
 568         kfree(vblk);
 569 out_free_index:
 570         ida_simple_remove(&vd_index_ida, index);
 571 out:
 572         return err;
 573 }
 574
 575 static void __devexit virtblk_remove(struct virtio_device *vdev)
 576 {
 577         struct virtio_blk *vblk = vdev->priv;
 578         int index = vblk->index;
 579         struct virtblk_req *vbr;
 580         unsigned long flags;
 581
 582         /* Prevent config work handler from accessing the device. */
 583         mutex_lock(&vblk->config_lock);
 584         vblk->config_enable = false;
 585         mutex_unlock(&vblk->config_lock);
 586
 587         /* Stop all the virtqueues. */
 588         vdev->config->reset(vdev);
 589
 590         flush_work(&vblk->config_work);
 591
 592         del_gendisk(vblk->disk);
 593
 594         /* Abort requests dispatched to driver. */
 595         spin_lock_irqsave(&vblk->lock, flags);
 596         while ((vbr = virtqueue_detach_unused_buf(vblk->vq))) {
 597                 __blk_end_request_all(vbr->req, -EIO);
 598                 mempool_free(vbr, vblk->pool);
 599         }
 600         spin_unlock_irqrestore(&vblk->lock, flags);
 601
 602         blk_cleanup_queue(vblk->disk->queue);
 603         put_disk(vblk->disk);
 604         mempool_destroy(vblk->pool);
 605         vdev->config->del_vqs(vdev);
 606         kfree(vblk);
 607         ida_simple_remove(&vd_index_ida, index);
 608 }
 609
 610 #ifdef CONFIG_PM
 611 static int virtblk_freeze(struct virtio_device *vdev)
 612 {
 613         struct virtio_blk *vblk = vdev->priv;
 614
 615         /* Ensure we don't receive any more interrupts */
 616         vdev->config->reset(vdev);
 617
 618         /* Prevent config work handler from accessing the device. */
 619         mutex_lock(&vblk->config_lock);
 620         vblk->config_enable = false;
 621         mutex_unlock(&vblk->config_lock);
 622
 623         flush_work(&vblk->config_work);
 624
 625         spin_lock_irq(vblk->disk->queue->queue_lock);
 626         blk_stop_queue(vblk->disk->queue);
 627         spin_unlock_irq(vblk->disk->queue->queue_lock);
 628         blk_sync_queue(vblk->disk->queue);
 629
 630         vdev->config->del_vqs(vdev);
 631         return 0;
 632 }
 633
 634 static int virtblk_restore(struct virtio_device *vdev)
 635 {
 636         struct virtio_blk *vblk = vdev->priv;
 637         int ret;
 638
 639         vblk->config_enable = true;
 640         ret = init_vq(vdev->priv);
 641         if (!ret) {
 642                 spin_lock_irq(vblk->disk->queue->queue_lock);
 643                 blk_start_queue(vblk->disk->queue);
 644                 spin_unlock_irq(vblk->disk->queue->queue_lock);
 645         }
 646         return ret;
 647 }
 648 #endif
 649
 650 static const struct virtio_device_id id_table[] = {
 651         { VIRTIO_ID_BLOCK, VIRTIO_DEV_ANY_ID },
 652         { 0 },
 653 };
 654
 655 static unsigned int features[] = {
 656         VIRTIO_BLK_F_SEG_MAX, VIRTIO_BLK_F_SIZE_MAX, VIRTIO_BLK_F_GEOMETRY,
 657         VIRTIO_BLK_F_RO, VIRTIO_BLK_F_BLK_SIZE, VIRTIO_BLK_F_SCSI,
 658         VIRTIO_BLK_F_FLUSH, VIRTIO_BLK_F_TOPOLOGY
 659 };
 660
 661 /*
 662  * virtio_blk causes spurious section mismatch warning by
 663  * simultaneously referring to a __devinit and a __devexit function.
 664  * Use __refdata to avoid this warning.
 665  */
 666 static struct virtio_driver __refdata virtio_blk = {
 667         .feature_table          = features,
 668         .feature_table_size     = ARRAY_SIZE(features),
 669         .driver.name            = KBUILD_MODNAME,
 670         .driver.owner           = THIS_MODULE,
 671         .id_table               = id_table,
 672         .probe                  = virtblk_probe,
 673         .remove                 = __devexit_p(virtblk_remove),
 674         .config_changed         = virtblk_config_changed,
 675 #ifdef CONFIG_PM
 676         .freeze                 = virtblk_freeze,
 677         .restore                = virtblk_restore,
 678 #endif
 679 };
 680
 681 static int __init init(void)
 682 {
 683         int error;
 684
 685         virtblk_wq = alloc_workqueue("virtio-blk", 0, 0);
 686         if (!virtblk_wq)
 687                 return -ENOMEM;
 688
 689         major = register_blkdev(0, "virtblk");
 690         if (major < 0) {
 691                 error = major;
 692                 goto out_destroy_workqueue;
 693         }
 694
 695         error = register_virtio_driver(&virtio_blk);
 696         if (error)
 697                 goto out_unregister_blkdev;
 698         return 0;
 699
 700 out_unregister_blkdev:
 701         unregister_blkdev(major, "virtblk");
 702 out_destroy_workqueue:
 703         destroy_workqueue(virtblk_wq);
 704         return error;
 705 }
 706
 707 static void __exit fini(void)
 708 {
 709         unregister_blkdev(major, "virtblk");
 710         unregister_virtio_driver(&virtio_blk);
 711         destroy_workqueue(virtblk_wq);
 712 }
 713 module_init(init);
 714 module_exit(fini);
 715
 716 MODULE_DEVICE_TABLE(virtio, id_table);
 717 MODULE_DESCRIPTION("Virtio block driver");
 718 MODULE_LICENSE("GPL");