drivers/block/virtio_blk.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 //#define DEBUG
   3 #include <linux/spinlock.h>
   4 #include <linux/slab.h>
   5 #include <linux/blkdev.h>
   6 #include <linux/hdreg.h>
   7 #include <linux/module.h>
   8 #include <linux/mutex.h>
   9 #include <linux/interrupt.h>
  10 #include <linux/virtio.h>
  11 #include <linux/virtio_blk.h>
  12 #include <linux/scatterlist.h>
  13 #include <linux/string_helpers.h>
  14 #include <linux/idr.h>
  15 #include <linux/blk-mq.h>
  16 #include <linux/blk-mq-virtio.h>
  17 #include <linux/numa.h>
  18 #include <uapi/linux/virtio_ring.h>
  19
  20 #define PART_BITS 4
  21 #define VQ_NAME_LEN 16
  22 #define MAX_DISCARD_SEGMENTS 256u
  23
  24 /* The maximum number of sg elements that fit into a virtqueue */
  25 #define VIRTIO_BLK_MAX_SG_ELEMS 32768
  26
  27 #ifdef CONFIG_ARCH_NO_SG_CHAIN
  28 #define VIRTIO_BLK_INLINE_SG_CNT        0
  29 #else
  30 #define VIRTIO_BLK_INLINE_SG_CNT        2
  31 #endif
  32
  33 static unsigned int num_request_queues;
  34 module_param(num_request_queues, uint, 0644);
  35 MODULE_PARM_DESC(num_request_queues,
  36                  "Limit the number of request queues to use for blk device. "
  37                  "0 for no limit. "
  38                  "Values > nr_cpu_ids truncated to nr_cpu_ids.");
  39
  40 static unsigned int poll_queues;
  41 module_param(poll_queues, uint, 0644);
  42 MODULE_PARM_DESC(poll_queues, "The number of dedicated virtqueues for polling I/O");
  43
  44 static int major;
  45 static DEFINE_IDA(vd_index_ida);
  46
  47 static struct workqueue_struct *virtblk_wq;
  48
  49 struct virtio_blk_vq {
  50         struct virtqueue *vq;
  51         spinlock_t lock;
  52         char name[VQ_NAME_LEN];
  53 } ____cacheline_aligned_in_smp;
  54
  55 struct virtio_blk {
  56         /*
  57          * This mutex must be held by anything that may run after
  58          * virtblk_remove() sets vblk->vdev to NULL.
  59          *
  60          * blk-mq, virtqueue processing, and sysfs attribute code paths are
  61          * shut down before vblk->vdev is set to NULL and therefore do not need
  62          * to hold this mutex.
  63          */
  64         struct mutex vdev_mutex;
  65         struct virtio_device *vdev;
  66
  67         /* The disk structure for the kernel. */
  68         struct gendisk *disk;
  69
  70         /* Block layer tags. */
  71         struct blk_mq_tag_set tag_set;
  72
  73         /* Process context for config space updates */
  74         struct work_struct config_work;
  75
  76         /* Ida index - used to track minor number allocations. */
  77         int index;
  78
  79         /* num of vqs */
  80         int num_vqs;
  81         int io_queues[HCTX_MAX_TYPES];
  82         struct virtio_blk_vq *vqs;
  83 };
  84
  85 struct virtblk_req {
  86         struct virtio_blk_outhdr out_hdr;
  87         u8 status;
  88         struct sg_table sg_table;
  89         struct scatterlist sg[];
  90 };
  91
  92 static inline blk_status_t virtblk_result(struct virtblk_req *vbr)
  93 {
  94         switch (vbr->status) {
  95         case VIRTIO_BLK_S_OK:
  96                 return BLK_STS_OK;
  97         case VIRTIO_BLK_S_UNSUPP:
  98                 return BLK_STS_NOTSUPP;
  99         default:
 100                 return BLK_STS_IOERR;
 101         }
 102 }
 103
 104 static inline struct virtio_blk_vq *get_virtio_blk_vq(struct blk_mq_hw_ctx *hctx)
 105 {
 106         struct virtio_blk *vblk = hctx->queue->queuedata;
 107         struct virtio_blk_vq *vq = &vblk->vqs[hctx->queue_num];
 108
 109         return vq;
 110 }
 111
 112 static int virtblk_add_req(struct virtqueue *vq, struct virtblk_req *vbr)
 113 {
 114         struct scatterlist hdr, status, *sgs[3];
 115         unsigned int num_out = 0, num_in = 0;
 116
 117         sg_init_one(&hdr, &vbr->out_hdr, sizeof(vbr->out_hdr));
 118         sgs[num_out++] = &hdr;
 119
 120         if (vbr->sg_table.nents) {
 121                 if (vbr->out_hdr.type & cpu_to_virtio32(vq->vdev, VIRTIO_BLK_T_OUT))
 122                         sgs[num_out++] = vbr->sg_table.sgl;
 123                 else
 124                         sgs[num_out + num_in++] = vbr->sg_table.sgl;
 125         }
 126
 127         sg_init_one(&status, &vbr->status, sizeof(vbr->status));
 128         sgs[num_out + num_in++] = &status;
 129
 130         return virtqueue_add_sgs(vq, sgs, num_out, num_in, vbr, GFP_ATOMIC);
 131 }
 132
 133 static int virtblk_setup_discard_write_zeroes_erase(struct request *req, bool unmap)
 134 {
 135         unsigned short segments = blk_rq_nr_discard_segments(req);
 136         unsigned short n = 0;
 137         struct virtio_blk_discard_write_zeroes *range;
 138         struct bio *bio;
 139         u32 flags = 0;
 140
 141         if (unmap)
 142                 flags |= VIRTIO_BLK_WRITE_ZEROES_FLAG_UNMAP;
 143
 144         range = kmalloc_array(segments, sizeof(*range), GFP_ATOMIC);
 145         if (!range)
 146                 return -ENOMEM;
 147
 148         /*
 149          * Single max discard segment means multi-range discard isn't
 150          * supported, and block layer only runs contiguity merge like
 151          * normal RW request. So we can't reply on bio for retrieving
 152          * each range info.
 153          */
 154         if (queue_max_discard_segments(req->q) == 1) {
 155                 range[0].flags = cpu_to_le32(flags);
 156                 range[0].num_sectors = cpu_to_le32(blk_rq_sectors(req));
 157                 range[0].sector = cpu_to_le64(blk_rq_pos(req));
 158                 n = 1;
 159         } else {
 160                 __rq_for_each_bio(bio, req) {
 161                         u64 sector = bio->bi_iter.bi_sector;
 162                         u32 num_sectors = bio->bi_iter.bi_size >> SECTOR_SHIFT;
 163
 164                         range[n].flags = cpu_to_le32(flags);
 165                         range[n].num_sectors = cpu_to_le32(num_sectors);
 166                         range[n].sector = cpu_to_le64(sector);
 167                         n++;
 168                 }
 169         }
 170
 171         WARN_ON_ONCE(n != segments);
 172
 173         req->special_vec.bv_page = virt_to_page(range);
 174         req->special_vec.bv_offset = offset_in_page(range);
 175         req->special_vec.bv_len = sizeof(*range) * segments;
 176         req->rq_flags |= RQF_SPECIAL_PAYLOAD;
 177
 178         return 0;
 179 }
 180
 181 static void virtblk_unmap_data(struct request *req, struct virtblk_req *vbr)
 182 {
 183         if (blk_rq_nr_phys_segments(req))
 184                 sg_free_table_chained(&vbr->sg_table,
 185                                       VIRTIO_BLK_INLINE_SG_CNT);
 186 }
 187
 188 static int virtblk_map_data(struct blk_mq_hw_ctx *hctx, struct request *req,
 189                 struct virtblk_req *vbr)
 190 {
 191         int err;
 192
 193         if (!blk_rq_nr_phys_segments(req))
 194                 return 0;
 195
 196         vbr->sg_table.sgl = vbr->sg;
 197         err = sg_alloc_table_chained(&vbr->sg_table,
 198                                      blk_rq_nr_phys_segments(req),
 199                                      vbr->sg_table.sgl,
 200                                      VIRTIO_BLK_INLINE_SG_CNT);
 201         if (unlikely(err))
 202                 return -ENOMEM;
 203
 204         return blk_rq_map_sg(hctx->queue, req, vbr->sg_table.sgl);
 205 }
 206
 207 static void virtblk_cleanup_cmd(struct request *req)
 208 {
 209         if (req->rq_flags & RQF_SPECIAL_PAYLOAD)
 210                 kfree(bvec_virt(&req->special_vec));
 211 }
 212
 213 static blk_status_t virtblk_setup_cmd(struct virtio_device *vdev,
 214                                       struct request *req,
 215                                       struct virtblk_req *vbr)
 216 {
 217         bool unmap = false;
 218         u32 type;
 219
 220         vbr->out_hdr.sector = 0;
 221
 222         switch (req_op(req)) {
 223         case REQ_OP_READ:
 224                 type = VIRTIO_BLK_T_IN;
 225                 vbr->out_hdr.sector = cpu_to_virtio64(vdev,
 226                                                       blk_rq_pos(req));
 227                 break;
 228         case REQ_OP_WRITE:
 229                 type = VIRTIO_BLK_T_OUT;
 230                 vbr->out_hdr.sector = cpu_to_virtio64(vdev,
 231                                                       blk_rq_pos(req));
 232                 break;
 233         case REQ_OP_FLUSH:
 234                 type = VIRTIO_BLK_T_FLUSH;
 235                 break;
 236         case REQ_OP_DISCARD:
 237                 type = VIRTIO_BLK_T_DISCARD;
 238                 break;
 239         case REQ_OP_WRITE_ZEROES:
 240                 type = VIRTIO_BLK_T_WRITE_ZEROES;
 241                 unmap = !(req->cmd_flags & REQ_NOUNMAP);
 242                 break;
 243         case REQ_OP_SECURE_ERASE:
 244                 type = VIRTIO_BLK_T_SECURE_ERASE;
 245                 break;
 246         case REQ_OP_DRV_IN:
 247                 type = VIRTIO_BLK_T_GET_ID;
 248                 break;
 249         default:
 250                 WARN_ON_ONCE(1);
 251                 return BLK_STS_IOERR;
 252         }
 253
 254         vbr->out_hdr.type = cpu_to_virtio32(vdev, type);
 255         vbr->out_hdr.ioprio = cpu_to_virtio32(vdev, req_get_ioprio(req));
 256
 257         if (type == VIRTIO_BLK_T_DISCARD || type == VIRTIO_BLK_T_WRITE_ZEROES ||
 258             type == VIRTIO_BLK_T_SECURE_ERASE) {
 259                 if (virtblk_setup_discard_write_zeroes_erase(req, unmap))
 260                         return BLK_STS_RESOURCE;
 261         }
 262
 263         return 0;
 264 }
 265
 266 static inline void virtblk_request_done(struct request *req)
 267 {
 268         struct virtblk_req *vbr = blk_mq_rq_to_pdu(req);
 269
 270         virtblk_unmap_data(req, vbr);
 271         virtblk_cleanup_cmd(req);
 272         blk_mq_end_request(req, virtblk_result(vbr));
 273 }
 274
 275 static void virtblk_done(struct virtqueue *vq)
 276 {
 277         struct virtio_blk *vblk = vq->vdev->priv;
 278         bool req_done = false;
 279         int qid = vq->index;
 280         struct virtblk_req *vbr;
 281         unsigned long flags;
 282         unsigned int len;
 283
 284         spin_lock_irqsave(&vblk->vqs[qid].lock, flags);
 285         do {
 286                 virtqueue_disable_cb(vq);
 287                 while ((vbr = virtqueue_get_buf(vblk->vqs[qid].vq, &len)) != NULL) {
 288                         struct request *req = blk_mq_rq_from_pdu(vbr);
 289
 290                         if (likely(!blk_should_fake_timeout(req->q)))
 291                                 blk_mq_complete_request(req);
 292                         req_done = true;
 293                 }
 294                 if (unlikely(virtqueue_is_broken(vq)))
 295                         break;
 296         } while (!virtqueue_enable_cb(vq));
 297
 298         /* In case queue is stopped waiting for more buffers. */
 299         if (req_done)
 300                 blk_mq_start_stopped_hw_queues(vblk->disk->queue, true);
 301         spin_unlock_irqrestore(&vblk->vqs[qid].lock, flags);
 302 }
 303
 304 static void virtio_commit_rqs(struct blk_mq_hw_ctx *hctx)
 305 {
 306         struct virtio_blk *vblk = hctx->queue->queuedata;
 307         struct virtio_blk_vq *vq = &vblk->vqs[hctx->queue_num];
 308         bool kick;
 309
 310         spin_lock_irq(&vq->lock);
 311         kick = virtqueue_kick_prepare(vq->vq);
 312         spin_unlock_irq(&vq->lock);
 313
 314         if (kick)
 315                 virtqueue_notify(vq->vq);
 316 }
 317
 318 static blk_status_t virtblk_fail_to_queue(struct request *req, int rc)
 319 {
 320         virtblk_cleanup_cmd(req);
 321         switch (rc) {
 322         case -ENOSPC:
 323                 return BLK_STS_DEV_RESOURCE;
 324         case -ENOMEM:
 325                 return BLK_STS_RESOURCE;
 326         default:
 327                 return BLK_STS_IOERR;
 328         }
 329 }
 330
 331 static blk_status_t virtblk_prep_rq(struct blk_mq_hw_ctx *hctx,
 332                                         struct virtio_blk *vblk,
 333                                         struct request *req,
 334                                         struct virtblk_req *vbr)
 335 {
 336         blk_status_t status;
 337         int num;
 338
 339         status = virtblk_setup_cmd(vblk->vdev, req, vbr);
 340         if (unlikely(status))
 341                 return status;
 342
 343         num = virtblk_map_data(hctx, req, vbr);
 344         if (unlikely(num < 0))
 345                 return virtblk_fail_to_queue(req, -ENOMEM);
 346         vbr->sg_table.nents = num;
 347
 348         blk_mq_start_request(req);
 349
 350         return BLK_STS_OK;
 351 }
 352
 353 static blk_status_t virtio_queue_rq(struct blk_mq_hw_ctx *hctx,
 354                            const struct blk_mq_queue_data *bd)
 355 {
 356         struct virtio_blk *vblk = hctx->queue->queuedata;
 357         struct request *req = bd->rq;
 358         struct virtblk_req *vbr = blk_mq_rq_to_pdu(req);
 359         unsigned long flags;
 360         int qid = hctx->queue_num;
 361         bool notify = false;
 362         blk_status_t status;
 363         int err;
 364
 365         status = virtblk_prep_rq(hctx, vblk, req, vbr);
 366         if (unlikely(status))
 367                 return status;
 368
 369         spin_lock_irqsave(&vblk->vqs[qid].lock, flags);
 370         err = virtblk_add_req(vblk->vqs[qid].vq, vbr);
 371         if (err) {
 372                 virtqueue_kick(vblk->vqs[qid].vq);
 373                 /* Don't stop the queue if -ENOMEM: we may have failed to
 374                  * bounce the buffer due to global resource outage.
 375                  */
 376                 if (err == -ENOSPC)
 377                         blk_mq_stop_hw_queue(hctx);
 378                 spin_unlock_irqrestore(&vblk->vqs[qid].lock, flags);
 379                 virtblk_unmap_data(req, vbr);
 380                 return virtblk_fail_to_queue(req, err);
 381         }
 382
 383         if (bd->last && virtqueue_kick_prepare(vblk->vqs[qid].vq))
 384                 notify = true;
 385         spin_unlock_irqrestore(&vblk->vqs[qid].lock, flags);
 386
 387         if (notify)
 388                 virtqueue_notify(vblk->vqs[qid].vq);
 389         return BLK_STS_OK;
 390 }
 391
 392 static bool virtblk_prep_rq_batch(struct request *req)
 393 {
 394         struct virtio_blk *vblk = req->mq_hctx->queue->queuedata;
 395         struct virtblk_req *vbr = blk_mq_rq_to_pdu(req);
 396
 397         req->mq_hctx->tags->rqs[req->tag] = req;
 398
 399         return virtblk_prep_rq(req->mq_hctx, vblk, req, vbr) == BLK_STS_OK;
 400 }
 401
 402 static bool virtblk_add_req_batch(struct virtio_blk_vq *vq,
 403                                         struct request **rqlist)
 404 {
 405         unsigned long flags;
 406         int err;
 407         bool kick;
 408
 409         spin_lock_irqsave(&vq->lock, flags);
 410
 411         while (!rq_list_empty(*rqlist)) {
 412                 struct request *req = rq_list_pop(rqlist);
 413                 struct virtblk_req *vbr = blk_mq_rq_to_pdu(req);
 414
 415                 err = virtblk_add_req(vq->vq, vbr);
 416                 if (err) {
 417                         virtblk_unmap_data(req, vbr);
 418                         virtblk_cleanup_cmd(req);
 419                         blk_mq_requeue_request(req, true);
 420                 }
 421         }
 422
 423         kick = virtqueue_kick_prepare(vq->vq);
 424         spin_unlock_irqrestore(&vq->lock, flags);
 425
 426         return kick;
 427 }
 428
 429 static void virtio_queue_rqs(struct request **rqlist)
 430 {
 431         struct request *req, *next, *prev = NULL;
 432         struct request *requeue_list = NULL;
 433
 434         rq_list_for_each_safe(rqlist, req, next) {
 435                 struct virtio_blk_vq *vq = get_virtio_blk_vq(req->mq_hctx);
 436                 bool kick;
 437
 438                 if (!virtblk_prep_rq_batch(req)) {
 439                         rq_list_move(rqlist, &requeue_list, req, prev);
 440                         req = prev;
 441                         if (!req)
 442                                 continue;
 443                 }
 444
 445                 if (!next || req->mq_hctx != next->mq_hctx) {
 446                         req->rq_next = NULL;
 447                         kick = virtblk_add_req_batch(vq, rqlist);
 448                         if (kick)
 449                                 virtqueue_notify(vq->vq);
 450
 451                         *rqlist = next;
 452                         prev = NULL;
 453                 } else
 454                         prev = req;
 455         }
 456
 457         *rqlist = requeue_list;
 458 }
 459
 460 /* return id (s/n) string for *disk to *id_str
 461  */
 462 static int virtblk_get_id(struct gendisk *disk, char *id_str)
 463 {
 464         struct virtio_blk *vblk = disk->private_data;
 465         struct request_queue *q = vblk->disk->queue;
 466         struct request *req;
 467         int err;
 468
 469         req = blk_mq_alloc_request(q, REQ_OP_DRV_IN, 0);
 470         if (IS_ERR(req))
 471                 return PTR_ERR(req);
 472
 473         err = blk_rq_map_kern(q, req, id_str, VIRTIO_BLK_ID_BYTES, GFP_KERNEL);
 474         if (err)
 475                 goto out;
 476
 477         blk_execute_rq(req, false);
 478         err = blk_status_to_errno(virtblk_result(blk_mq_rq_to_pdu(req)));
 479 out:
 480         blk_mq_free_request(req);
 481         return err;
 482 }
 483
 484 /* We provide getgeo only to please some old bootloader/partitioning tools */
 485 static int virtblk_getgeo(struct block_device *bd, struct hd_geometry *geo)
 486 {
 487         struct virtio_blk *vblk = bd->bd_disk->private_data;
 488         int ret = 0;
 489
 490         mutex_lock(&vblk->vdev_mutex);
 491
 492         if (!vblk->vdev) {
 493                 ret = -ENXIO;
 494                 goto out;
 495         }
 496
 497         /* see if the host passed in geometry config */
 498         if (virtio_has_feature(vblk->vdev, VIRTIO_BLK_F_GEOMETRY)) {
 499                 virtio_cread(vblk->vdev, struct virtio_blk_config,
 500                              geometry.cylinders, &geo->cylinders);
 501                 virtio_cread(vblk->vdev, struct virtio_blk_config,
 502                              geometry.heads, &geo->heads);
 503                 virtio_cread(vblk->vdev, struct virtio_blk_config,
 504                              geometry.sectors, &geo->sectors);
 505         } else {
 506                 /* some standard values, similar to sd */
 507                 geo->heads = 1 << 6;
 508                 geo->sectors = 1 << 5;
 509                 geo->cylinders = get_capacity(bd->bd_disk) >> 11;
 510         }
 511 out:
 512         mutex_unlock(&vblk->vdev_mutex);
 513         return ret;
 514 }
 515
 516 static void virtblk_free_disk(struct gendisk *disk)
 517 {
 518         struct virtio_blk *vblk = disk->private_data;
 519
 520         ida_free(&vd_index_ida, vblk->index);
 521         mutex_destroy(&vblk->vdev_mutex);
 522         kfree(vblk);
 523 }
 524
 525 static const struct block_device_operations virtblk_fops = {
 526         .owner          = THIS_MODULE,
 527         .getgeo         = virtblk_getgeo,
 528         .free_disk      = virtblk_free_disk,
 529 };
 530
 531 static int index_to_minor(int index)
 532 {
 533         return index << PART_BITS;
 534 }
 535
 536 static int minor_to_index(int minor)
 537 {
 538         return minor >> PART_BITS;
 539 }
 540
 541 static ssize_t serial_show(struct device *dev,
 542                            struct device_attribute *attr, char *buf)
 543 {
 544         struct gendisk *disk = dev_to_disk(dev);
 545         int err;
 546
 547         /* sysfs gives us a PAGE_SIZE buffer */
 548         BUILD_BUG_ON(PAGE_SIZE < VIRTIO_BLK_ID_BYTES);
 549
 550         buf[VIRTIO_BLK_ID_BYTES] = '\0';
 551         err = virtblk_get_id(disk, buf);
 552         if (!err)
 553                 return strlen(buf);
 554
 555         if (err == -EIO) /* Unsupported? Make it empty. */
 556                 return 0;
 557
 558         return err;
 559 }
 560
 561 static DEVICE_ATTR_RO(serial);
 562
 563 /* The queue's logical block size must be set before calling this */
 564 static void virtblk_update_capacity(struct virtio_blk *vblk, bool resize)
 565 {
 566         struct virtio_device *vdev = vblk->vdev;
 567         struct request_queue *q = vblk->disk->queue;
 568         char cap_str_2[10], cap_str_10[10];
 569         unsigned long long nblocks;
 570         u64 capacity;
 571
 572         /* Host must always specify the capacity. */
 573         virtio_cread(vdev, struct virtio_blk_config, capacity, &capacity);
 574
 575         nblocks = DIV_ROUND_UP_ULL(capacity, queue_logical_block_size(q) >> 9);
 576
 577         string_get_size(nblocks, queue_logical_block_size(q),
 578                         STRING_UNITS_2, cap_str_2, sizeof(cap_str_2));
 579         string_get_size(nblocks, queue_logical_block_size(q),
 580                         STRING_UNITS_10, cap_str_10, sizeof(cap_str_10));
 581
 582         dev_notice(&vdev->dev,
 583                    "[%s] %s%llu %d-byte logical blocks (%s/%s)\n",
 584                    vblk->disk->disk_name,
 585                    resize ? "new size: " : "",
 586                    nblocks,
 587                    queue_logical_block_size(q),
 588                    cap_str_10,
 589                    cap_str_2);
 590
 591         set_capacity_and_notify(vblk->disk, capacity);
 592 }
 593
 594 static void virtblk_config_changed_work(struct work_struct *work)
 595 {
 596         struct virtio_blk *vblk =
 597                 container_of(work, struct virtio_blk, config_work);
 598
 599         virtblk_update_capacity(vblk, true);
 600 }
 601
 602 static void virtblk_config_changed(struct virtio_device *vdev)
 603 {
 604         struct virtio_blk *vblk = vdev->priv;
 605
 606         queue_work(virtblk_wq, &vblk->config_work);
 607 }
 608
 609 static int init_vq(struct virtio_blk *vblk)
 610 {
 611         int err;
 612         int i;
 613         vq_callback_t **callbacks;
 614         const char **names;
 615         struct virtqueue **vqs;
 616         unsigned short num_vqs;
 617         unsigned int num_poll_vqs;
 618         struct virtio_device *vdev = vblk->vdev;
 619         struct irq_affinity desc = { 0, };
 620
 621         err = virtio_cread_feature(vdev, VIRTIO_BLK_F_MQ,
 622                                    struct virtio_blk_config, num_queues,
 623                                    &num_vqs);
 624         if (err)
 625                 num_vqs = 1;
 626
 627         if (!err && !num_vqs) {
 628                 dev_err(&vdev->dev, "MQ advertised but zero queues reported\n");
 629                 return -EINVAL;
 630         }
 631
 632         num_vqs = min_t(unsigned int,
 633                         min_not_zero(num_request_queues, nr_cpu_ids),
 634                         num_vqs);
 635
 636         num_poll_vqs = min_t(unsigned int, poll_queues, num_vqs - 1);
 637
 638         vblk->io_queues[HCTX_TYPE_DEFAULT] = num_vqs - num_poll_vqs;
 639         vblk->io_queues[HCTX_TYPE_READ] = 0;
 640         vblk->io_queues[HCTX_TYPE_POLL] = num_poll_vqs;
 641
 642         dev_info(&vdev->dev, "%d/%d/%d default/read/poll queues\n",
 643                                 vblk->io_queues[HCTX_TYPE_DEFAULT],
 644                                 vblk->io_queues[HCTX_TYPE_READ],
 645                                 vblk->io_queues[HCTX_TYPE_POLL]);
 646
 647         vblk->vqs = kmalloc_array(num_vqs, sizeof(*vblk->vqs), GFP_KERNEL);
 648         if (!vblk->vqs)
 649                 return -ENOMEM;
 650
 651         names = kmalloc_array(num_vqs, sizeof(*names), GFP_KERNEL);
 652         callbacks = kmalloc_array(num_vqs, sizeof(*callbacks), GFP_KERNEL);
 653         vqs = kmalloc_array(num_vqs, sizeof(*vqs), GFP_KERNEL);
 654         if (!names || !callbacks || !vqs) {
 655                 err = -ENOMEM;
 656                 goto out;
 657         }
 658
 659         for (i = 0; i < num_vqs - num_poll_vqs; i++) {
 660                 callbacks[i] = virtblk_done;
 661                 snprintf(vblk->vqs[i].name, VQ_NAME_LEN, "req.%d", i);
 662                 names[i] = vblk->vqs[i].name;
 663         }
 664
 665         for (; i < num_vqs; i++) {
 666                 callbacks[i] = NULL;
 667                 snprintf(vblk->vqs[i].name, VQ_NAME_LEN, "req_poll.%d", i);
 668                 names[i] = vblk->vqs[i].name;
 669         }
 670
 671         /* Discover virtqueues and write information to configuration.  */
 672         err = virtio_find_vqs(vdev, num_vqs, vqs, callbacks, names, &desc);
 673         if (err)
 674                 goto out;
 675
 676         for (i = 0; i < num_vqs; i++) {
 677                 spin_lock_init(&vblk->vqs[i].lock);
 678                 vblk->vqs[i].vq = vqs[i];
 679         }
 680         vblk->num_vqs = num_vqs;
 681
 682 out:
 683         kfree(vqs);
 684         kfree(callbacks);
 685         kfree(names);
 686         if (err)
 687                 kfree(vblk->vqs);
 688         return err;
 689 }
 690
 691 /*
 692  * Legacy naming scheme used for virtio devices.  We are stuck with it for
 693  * virtio blk but don't ever use it for any new driver.
 694  */
 695 static int virtblk_name_format(char *prefix, int index, char *buf, int buflen)
 696 {
 697         const int base = 'z' - 'a' + 1;
 698         char *begin = buf + strlen(prefix);
 699         char *end = buf + buflen;
 700         char *p;
 701         int unit;
 702
 703         p = end - 1;
 704         *p = '\0';
 705         unit = base;
 706         do {
 707                 if (p == begin)
 708                         return -EINVAL;
 709                 *--p = 'a' + (index % unit);
 710                 index = (index / unit) - 1;
 711         } while (index >= 0);
 712
 713         memmove(begin, p, end - p);
 714         memcpy(buf, prefix, strlen(prefix));
 715
 716         return 0;
 717 }
 718
 719 static int virtblk_get_cache_mode(struct virtio_device *vdev)
 720 {
 721         u8 writeback;
 722         int err;
 723
 724         err = virtio_cread_feature(vdev, VIRTIO_BLK_F_CONFIG_WCE,
 725                                    struct virtio_blk_config, wce,
 726                                    &writeback);
 727
 728         /*
 729          * If WCE is not configurable and flush is not available,
 730          * assume no writeback cache is in use.
 731          */
 732         if (err)
 733                 writeback = virtio_has_feature(vdev, VIRTIO_BLK_F_FLUSH);
 734
 735         return writeback;
 736 }
 737
 738 static void virtblk_update_cache_mode(struct virtio_device *vdev)
 739 {
 740         u8 writeback = virtblk_get_cache_mode(vdev);
 741         struct virtio_blk *vblk = vdev->priv;
 742
 743         blk_queue_write_cache(vblk->disk->queue, writeback, false);
 744 }
 745
 746 static const char *const virtblk_cache_types[] = {
 747         "write through", "write back"
 748 };
 749
 750 static ssize_t
 751 cache_type_store(struct device *dev, struct device_attribute *attr,
 752                  const char *buf, size_t count)
 753 {
 754         struct gendisk *disk = dev_to_disk(dev);
 755         struct virtio_blk *vblk = disk->private_data;
 756         struct virtio_device *vdev = vblk->vdev;
 757         int i;
 758
 759         BUG_ON(!virtio_has_feature(vblk->vdev, VIRTIO_BLK_F_CONFIG_WCE));
 760         i = sysfs_match_string(virtblk_cache_types, buf);
 761         if (i < 0)
 762                 return i;
 763
 764         virtio_cwrite8(vdev, offsetof(struct virtio_blk_config, wce), i);
 765         virtblk_update_cache_mode(vdev);
 766         return count;
 767 }
 768
 769 static ssize_t
 770 cache_type_show(struct device *dev, struct device_attribute *attr, char *buf)
 771 {
 772         struct gendisk *disk = dev_to_disk(dev);
 773         struct virtio_blk *vblk = disk->private_data;
 774         u8 writeback = virtblk_get_cache_mode(vblk->vdev);
 775
 776         BUG_ON(writeback >= ARRAY_SIZE(virtblk_cache_types));
 777         return sysfs_emit(buf, "%s\n", virtblk_cache_types[writeback]);
 778 }
 779
 780 static DEVICE_ATTR_RW(cache_type);
 781
 782 static struct attribute *virtblk_attrs[] = {
 783         &dev_attr_serial.attr,
 784         &dev_attr_cache_type.attr,
 785         NULL,
 786 };
 787
 788 static umode_t virtblk_attrs_are_visible(struct kobject *kobj,
 789                 struct attribute *a, int n)
 790 {
 791         struct device *dev = kobj_to_dev(kobj);
 792         struct gendisk *disk = dev_to_disk(dev);
 793         struct virtio_blk *vblk = disk->private_data;
 794         struct virtio_device *vdev = vblk->vdev;
 795
 796         if (a == &dev_attr_cache_type.attr &&
 797             !virtio_has_feature(vdev, VIRTIO_BLK_F_CONFIG_WCE))
 798                 return S_IRUGO;
 799
 800         return a->mode;
 801 }
 802
 803 static const struct attribute_group virtblk_attr_group = {
 804         .attrs = virtblk_attrs,
 805         .is_visible = virtblk_attrs_are_visible,
 806 };
 807
 808 static const struct attribute_group *virtblk_attr_groups[] = {
 809         &virtblk_attr_group,
 810         NULL,
 811 };
 812
 813 static void virtblk_map_queues(struct blk_mq_tag_set *set)
 814 {
 815         struct virtio_blk *vblk = set->driver_data;
 816         int i, qoff;
 817
 818         for (i = 0, qoff = 0; i < set->nr_maps; i++) {
 819                 struct blk_mq_queue_map *map = &set->map[i];
 820
 821                 map->nr_queues = vblk->io_queues[i];
 822                 map->queue_offset = qoff;
 823                 qoff += map->nr_queues;
 824
 825                 if (map->nr_queues == 0)
 826                         continue;
 827
 828                 /*
 829                  * Regular queues have interrupts and hence CPU affinity is
 830                  * defined by the core virtio code, but polling queues have
 831                  * no interrupts so we let the block layer assign CPU affinity.
 832                  */
 833                 if (i == HCTX_TYPE_POLL)
 834                         blk_mq_map_queues(&set->map[i]);
 835                 else
 836                         blk_mq_virtio_map_queues(&set->map[i], vblk->vdev, 0);
 837         }
 838 }
 839
 840 static void virtblk_complete_batch(struct io_comp_batch *iob)
 841 {
 842         struct request *req;
 843
 844         rq_list_for_each(&iob->req_list, req) {
 845                 virtblk_unmap_data(req, blk_mq_rq_to_pdu(req));
 846                 virtblk_cleanup_cmd(req);
 847         }
 848         blk_mq_end_request_batch(iob);
 849 }
 850
 851 static int virtblk_poll(struct blk_mq_hw_ctx *hctx, struct io_comp_batch *iob)
 852 {
 853         struct virtio_blk *vblk = hctx->queue->queuedata;
 854         struct virtio_blk_vq *vq = get_virtio_blk_vq(hctx);
 855         struct virtblk_req *vbr;
 856         unsigned long flags;
 857         unsigned int len;
 858         int found = 0;
 859
 860         spin_lock_irqsave(&vq->lock, flags);
 861
 862         while ((vbr = virtqueue_get_buf(vq->vq, &len)) != NULL) {
 863                 struct request *req = blk_mq_rq_from_pdu(vbr);
 864
 865                 found++;
 866                 if (!blk_mq_add_to_batch(req, iob, vbr->status,
 867                                                 virtblk_complete_batch))
 868                         blk_mq_complete_request(req);
 869         }
 870
 871         if (found)
 872                 blk_mq_start_stopped_hw_queues(vblk->disk->queue, true);
 873
 874         spin_unlock_irqrestore(&vq->lock, flags);
 875
 876         return found;
 877 }
 878
 879 static const struct blk_mq_ops virtio_mq_ops = {
 880         .queue_rq       = virtio_queue_rq,
 881         .queue_rqs      = virtio_queue_rqs,
 882         .commit_rqs     = virtio_commit_rqs,
 883         .complete       = virtblk_request_done,
 884         .map_queues     = virtblk_map_queues,
 885         .poll           = virtblk_poll,
 886 };
 887
 888 static unsigned int virtblk_queue_depth;
 889 module_param_named(queue_depth, virtblk_queue_depth, uint, 0444);
 890
 891 static int virtblk_probe(struct virtio_device *vdev)
 892 {
 893         struct virtio_blk *vblk;
 894         struct request_queue *q;
 895         int err, index;
 896
 897         u32 v, blk_size, max_size, sg_elems, opt_io_size;
 898         u32 max_discard_segs = 0;
 899         u32 discard_granularity = 0;
 900         u16 min_io_size;
 901         u8 physical_block_exp, alignment_offset;
 902         unsigned int queue_depth;
 903
 904         if (!vdev->config->get) {
 905                 dev_err(&vdev->dev, "%s failure: config access disabled\n",
 906                         __func__);
 907                 return -EINVAL;
 908         }
 909
 910         err = ida_alloc_range(&vd_index_ida, 0,
 911                               minor_to_index(1 << MINORBITS) - 1, GFP_KERNEL);
 912         if (err < 0)
 913                 goto out;
 914         index = err;
 915
 916         /* We need to know how many segments before we allocate. */
 917         err = virtio_cread_feature(vdev, VIRTIO_BLK_F_SEG_MAX,
 918                                    struct virtio_blk_config, seg_max,
 919                                    &sg_elems);
 920
 921         /* We need at least one SG element, whatever they say. */
 922         if (err || !sg_elems)
 923                 sg_elems = 1;
 924
 925         /* Prevent integer overflows and honor max vq size */
 926         sg_elems = min_t(u32, sg_elems, VIRTIO_BLK_MAX_SG_ELEMS - 2);
 927
 928         vdev->priv = vblk = kmalloc(sizeof(*vblk), GFP_KERNEL);
 929         if (!vblk) {
 930                 err = -ENOMEM;
 931                 goto out_free_index;
 932         }
 933
 934         mutex_init(&vblk->vdev_mutex);
 935
 936         vblk->vdev = vdev;
 937
 938         INIT_WORK(&vblk->config_work, virtblk_config_changed_work);
 939
 940         err = init_vq(vblk);
 941         if (err)
 942                 goto out_free_vblk;
 943
 944         /* Default queue sizing is to fill the ring. */
 945         if (!virtblk_queue_depth) {
 946                 queue_depth = vblk->vqs[0].vq->num_free;
 947                 /* ... but without indirect descs, we use 2 descs per req */
 948                 if (!virtio_has_feature(vdev, VIRTIO_RING_F_INDIRECT_DESC))
 949                         queue_depth /= 2;
 950         } else {
 951                 queue_depth = virtblk_queue_depth;
 952         }
 953
 954         memset(&vblk->tag_set, 0, sizeof(vblk->tag_set));
 955         vblk->tag_set.ops = &virtio_mq_ops;
 956         vblk->tag_set.queue_depth = queue_depth;
 957         vblk->tag_set.numa_node = NUMA_NO_NODE;
 958         vblk->tag_set.flags = BLK_MQ_F_SHOULD_MERGE;
 959         vblk->tag_set.cmd_size =
 960                 sizeof(struct virtblk_req) +
 961                 sizeof(struct scatterlist) * VIRTIO_BLK_INLINE_SG_CNT;
 962         vblk->tag_set.driver_data = vblk;
 963         vblk->tag_set.nr_hw_queues = vblk->num_vqs;
 964         vblk->tag_set.nr_maps = 1;
 965         if (vblk->io_queues[HCTX_TYPE_POLL])
 966                 vblk->tag_set.nr_maps = 3;
 967
 968         err = blk_mq_alloc_tag_set(&vblk->tag_set);
 969         if (err)
 970                 goto out_free_vq;
 971
 972         vblk->disk = blk_mq_alloc_disk(&vblk->tag_set, vblk);
 973         if (IS_ERR(vblk->disk)) {
 974                 err = PTR_ERR(vblk->disk);
 975                 goto out_free_tags;
 976         }
 977         q = vblk->disk->queue;
 978
 979         virtblk_name_format("vd", index, vblk->disk->disk_name, DISK_NAME_LEN);
 980
 981         vblk->disk->major = major;
 982         vblk->disk->first_minor = index_to_minor(index);
 983         vblk->disk->minors = 1 << PART_BITS;
 984         vblk->disk->private_data = vblk;
 985         vblk->disk->fops = &virtblk_fops;
 986         vblk->index = index;
 987
 988         /* configure queue flush support */
 989         virtblk_update_cache_mode(vdev);
 990
 991         /* If disk is read-only in the host, the guest should obey */
 992         if (virtio_has_feature(vdev, VIRTIO_BLK_F_RO))
 993                 set_disk_ro(vblk->disk, 1);
 994
 995         /* We can handle whatever the host told us to handle. */
 996         blk_queue_max_segments(q, sg_elems);
 997
 998         /* No real sector limit. */
 999         blk_queue_max_hw_sectors(q, UINT_MAX);
1000
1001         max_size = virtio_max_dma_size(vdev);
1002
1003         /* Host can optionally specify maximum segment size and number of
1004          * segments. */
1005         err = virtio_cread_feature(vdev, VIRTIO_BLK_F_SIZE_MAX,
1006                                    struct virtio_blk_config, size_max, &v);
1007         if (!err)
1008                 max_size = min(max_size, v);
1009
1010         blk_queue_max_segment_size(q, max_size);
1011
1012         /* Host can optionally specify the block size of the device */
1013         err = virtio_cread_feature(vdev, VIRTIO_BLK_F_BLK_SIZE,
1014                                    struct virtio_blk_config, blk_size,
1015                                    &blk_size);
1016         if (!err) {
1017                 err = blk_validate_block_size(blk_size);
1018                 if (err) {
1019                         dev_err(&vdev->dev,
1020                                 "virtio_blk: invalid block size: 0x%x\n",
1021                                 blk_size);
1022                         goto out_cleanup_disk;
1023                 }
1024
1025                 blk_queue_logical_block_size(q, blk_size);
1026         } else
1027                 blk_size = queue_logical_block_size(q);
1028
1029         /* Use topology information if available */
1030         err = virtio_cread_feature(vdev, VIRTIO_BLK_F_TOPOLOGY,
1031                                    struct virtio_blk_config, physical_block_exp,
1032                                    &physical_block_exp);
1033         if (!err && physical_block_exp)
1034                 blk_queue_physical_block_size(q,
1035                                 blk_size * (1 << physical_block_exp));
1036
1037         err = virtio_cread_feature(vdev, VIRTIO_BLK_F_TOPOLOGY,
1038                                    struct virtio_blk_config, alignment_offset,
1039                                    &alignment_offset);
1040         if (!err && alignment_offset)
1041                 blk_queue_alignment_offset(q, blk_size * alignment_offset);
1042
1043         err = virtio_cread_feature(vdev, VIRTIO_BLK_F_TOPOLOGY,
1044                                    struct virtio_blk_config, min_io_size,
1045                                    &min_io_size);
1046         if (!err && min_io_size)
1047                 blk_queue_io_min(q, blk_size * min_io_size);
1048
1049         err = virtio_cread_feature(vdev, VIRTIO_BLK_F_TOPOLOGY,
1050                                    struct virtio_blk_config, opt_io_size,
1051                                    &opt_io_size);
1052         if (!err && opt_io_size)
1053                 blk_queue_io_opt(q, blk_size * opt_io_size);
1054
1055         if (virtio_has_feature(vdev, VIRTIO_BLK_F_DISCARD)) {
1056                 virtio_cread(vdev, struct virtio_blk_config,
1057                              discard_sector_alignment, &discard_granularity);
1058
1059                 virtio_cread(vdev, struct virtio_blk_config,
1060                              max_discard_sectors, &v);
1061                 blk_queue_max_discard_sectors(q, v ? v : UINT_MAX);
1062
1063                 virtio_cread(vdev, struct virtio_blk_config, max_discard_seg,
1064                              &max_discard_segs);
1065         }
1066
1067         if (virtio_has_feature(vdev, VIRTIO_BLK_F_WRITE_ZEROES)) {
1068                 virtio_cread(vdev, struct virtio_blk_config,
1069                              max_write_zeroes_sectors, &v);
1070                 blk_queue_max_write_zeroes_sectors(q, v ? v : UINT_MAX);
1071         }
1072
1073         /* The discard and secure erase limits are combined since the Linux
1074          * block layer uses the same limit for both commands.
1075          *
1076          * If both VIRTIO_BLK_F_SECURE_ERASE and VIRTIO_BLK_F_DISCARD features
1077          * are negotiated, we will use the minimum between the limits.
1078          *
1079          * discard sector alignment is set to the minimum between discard_sector_alignment
1080          * and secure_erase_sector_alignment.
1081          *
1082          * max discard sectors is set to the minimum between max_discard_seg and
1083          * max_secure_erase_seg.
1084          */
1085         if (virtio_has_feature(vdev, VIRTIO_BLK_F_SECURE_ERASE)) {
1086
1087                 virtio_cread(vdev, struct virtio_blk_config,
1088                              secure_erase_sector_alignment, &v);
1089
1090                 /* secure_erase_sector_alignment should not be zero, the device should set a
1091                  * valid number of sectors.
1092                  */
1093                 if (!v) {
1094                         dev_err(&vdev->dev,
1095                                 "virtio_blk: secure_erase_sector_alignment can't be 0\n");
1096                         err = -EINVAL;
1097                         goto out_cleanup_disk;
1098                 }
1099
1100                 discard_granularity = min_not_zero(discard_granularity, v);
1101
1102                 virtio_cread(vdev, struct virtio_blk_config,
1103                              max_secure_erase_sectors, &v);
1104
1105                 /* max_secure_erase_sectors should not be zero, the device should set a
1106                  * valid number of sectors.
1107                  */
1108                 if (!v) {
1109                         dev_err(&vdev->dev,
1110                                 "virtio_blk: max_secure_erase_sectors can't be 0\n");
1111                         err = -EINVAL;
1112                         goto out_cleanup_disk;
1113                 }
1114
1115                 blk_queue_max_secure_erase_sectors(q, v);
1116
1117                 virtio_cread(vdev, struct virtio_blk_config,
1118                              max_secure_erase_seg, &v);
1119
1120                 /* max_secure_erase_seg should not be zero, the device should set a
1121                  * valid number of segments
1122                  */
1123                 if (!v) {
1124                         dev_err(&vdev->dev,
1125                                 "virtio_blk: max_secure_erase_seg can't be 0\n");
1126                         err = -EINVAL;
1127                         goto out_cleanup_disk;
1128                 }
1129
1130                 max_discard_segs = min_not_zero(max_discard_segs, v);
1131         }
1132
1133         if (virtio_has_feature(vdev, VIRTIO_BLK_F_DISCARD) ||
1134             virtio_has_feature(vdev, VIRTIO_BLK_F_SECURE_ERASE)) {
1135                 /* max_discard_seg and discard_granularity will be 0 only
1136                  * if max_discard_seg and discard_sector_alignment fields in the virtio
1137                  * config are 0 and VIRTIO_BLK_F_SECURE_ERASE feature is not negotiated.
1138                  * In this case, we use default values.
1139                  */
1140                 if (!max_discard_segs)
1141                         max_discard_segs = sg_elems;
1142
1143                 blk_queue_max_discard_segments(q,
1144                                                min(max_discard_segs, MAX_DISCARD_SEGMENTS));
1145
1146                 if (discard_granularity)
1147                         q->limits.discard_granularity = discard_granularity << SECTOR_SHIFT;
1148                 else
1149                         q->limits.discard_granularity = blk_size;
1150         }
1151
1152         virtblk_update_capacity(vblk, false);
1153         virtio_device_ready(vdev);
1154
1155         err = device_add_disk(&vdev->dev, vblk->disk, virtblk_attr_groups);
1156         if (err)
1157                 goto out_cleanup_disk;
1158
1159         return 0;
1160
1161 out_cleanup_disk:
1162         put_disk(vblk->disk);
1163 out_free_tags:
1164         blk_mq_free_tag_set(&vblk->tag_set);
1165 out_free_vq:
1166         vdev->config->del_vqs(vdev);
1167         kfree(vblk->vqs);
1168 out_free_vblk:
1169         kfree(vblk);
1170 out_free_index:
1171         ida_free(&vd_index_ida, index);
1172 out:
1173         return err;
1174 }
1175
1176 static void virtblk_remove(struct virtio_device *vdev)
1177 {
1178         struct virtio_blk *vblk = vdev->priv;
1179
1180         /* Make sure no work handler is accessing the device. */
1181         flush_work(&vblk->config_work);
1182
1183         del_gendisk(vblk->disk);
1184         blk_mq_free_tag_set(&vblk->tag_set);
1185
1186         mutex_lock(&vblk->vdev_mutex);
1187
1188         /* Stop all the virtqueues. */
1189         virtio_reset_device(vdev);
1190
1191         /* Virtqueues are stopped, nothing can use vblk->vdev anymore. */
1192         vblk->vdev = NULL;
1193
1194         vdev->config->del_vqs(vdev);
1195         kfree(vblk->vqs);
1196
1197         mutex_unlock(&vblk->vdev_mutex);
1198
1199         put_disk(vblk->disk);
1200 }
1201
1202 #ifdef CONFIG_PM_SLEEP
1203 static int virtblk_freeze(struct virtio_device *vdev)
1204 {
1205         struct virtio_blk *vblk = vdev->priv;
1206
1207         /* Ensure we don't receive any more interrupts */
1208         virtio_reset_device(vdev);
1209
1210         /* Make sure no work handler is accessing the device. */
1211         flush_work(&vblk->config_work);
1212
1213         blk_mq_quiesce_queue(vblk->disk->queue);
1214
1215         vdev->config->del_vqs(vdev);
1216         kfree(vblk->vqs);
1217
1218         return 0;
1219 }
1220
1221 static int virtblk_restore(struct virtio_device *vdev)
1222 {
1223         struct virtio_blk *vblk = vdev->priv;
1224         int ret;
1225
1226         ret = init_vq(vdev->priv);
1227         if (ret)
1228                 return ret;
1229
1230         virtio_device_ready(vdev);
1231
1232         blk_mq_unquiesce_queue(vblk->disk->queue);
1233         return 0;
1234 }
1235 #endif
1236
1237 static const struct virtio_device_id id_table[] = {
1238         { VIRTIO_ID_BLOCK, VIRTIO_DEV_ANY_ID },
1239         { 0 },
1240 };
1241
1242 static unsigned int features_legacy[] = {
1243         VIRTIO_BLK_F_SEG_MAX, VIRTIO_BLK_F_SIZE_MAX, VIRTIO_BLK_F_GEOMETRY,
1244         VIRTIO_BLK_F_RO, VIRTIO_BLK_F_BLK_SIZE,
1245         VIRTIO_BLK_F_FLUSH, VIRTIO_BLK_F_TOPOLOGY, VIRTIO_BLK_F_CONFIG_WCE,
1246         VIRTIO_BLK_F_MQ, VIRTIO_BLK_F_DISCARD, VIRTIO_BLK_F_WRITE_ZEROES,
1247         VIRTIO_BLK_F_SECURE_ERASE,
1248 }
1249 ;
1250 static unsigned int features[] = {
1251         VIRTIO_BLK_F_SEG_MAX, VIRTIO_BLK_F_SIZE_MAX, VIRTIO_BLK_F_GEOMETRY,
1252         VIRTIO_BLK_F_RO, VIRTIO_BLK_F_BLK_SIZE,
1253         VIRTIO_BLK_F_FLUSH, VIRTIO_BLK_F_TOPOLOGY, VIRTIO_BLK_F_CONFIG_WCE,
1254         VIRTIO_BLK_F_MQ, VIRTIO_BLK_F_DISCARD, VIRTIO_BLK_F_WRITE_ZEROES,
1255         VIRTIO_BLK_F_SECURE_ERASE,
1256 };
1257
1258 static struct virtio_driver virtio_blk = {
1259         .feature_table                  = features,
1260         .feature_table_size             = ARRAY_SIZE(features),
1261         .feature_table_legacy           = features_legacy,
1262         .feature_table_size_legacy      = ARRAY_SIZE(features_legacy),
1263         .driver.name                    = KBUILD_MODNAME,
1264         .driver.owner                   = THIS_MODULE,
1265         .id_table                       = id_table,
1266         .probe                          = virtblk_probe,
1267         .remove                         = virtblk_remove,
1268         .config_changed                 = virtblk_config_changed,
1269 #ifdef CONFIG_PM_SLEEP
1270         .freeze                         = virtblk_freeze,
1271         .restore                        = virtblk_restore,
1272 #endif
1273 };
1274
1275 static int __init virtio_blk_init(void)
1276 {
1277         int error;
1278
1279         virtblk_wq = alloc_workqueue("virtio-blk", 0, 0);
1280         if (!virtblk_wq)
1281                 return -ENOMEM;
1282
1283         major = register_blkdev(0, "virtblk");
1284         if (major < 0) {
1285                 error = major;
1286                 goto out_destroy_workqueue;
1287         }
1288
1289         error = register_virtio_driver(&virtio_blk);
1290         if (error)
1291                 goto out_unregister_blkdev;
1292         return 0;
1293
1294 out_unregister_blkdev:
1295         unregister_blkdev(major, "virtblk");
1296 out_destroy_workqueue:
1297         destroy_workqueue(virtblk_wq);
1298         return error;
1299 }
1300
1301 static void __exit virtio_blk_fini(void)
1302 {
1303         unregister_virtio_driver(&virtio_blk);
1304         unregister_blkdev(major, "virtblk");
1305         destroy_workqueue(virtblk_wq);
1306 }
1307 module_init(virtio_blk_init);
1308 module_exit(virtio_blk_fini);
1309
1310 MODULE_DEVICE_TABLE(virtio, id_table);
1311 MODULE_DESCRIPTION("Virtio block driver");
1312 MODULE_LICENSE("GPL");