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
 338         status = virtblk_setup_cmd(vblk->vdev, req, vbr);
 339         if (unlikely(status))
 340                 return status;
 341
 342         vbr->sg_table.nents = virtblk_map_data(hctx, req, vbr);
 343         if (unlikely(vbr->sg_table.nents < 0))
 344                 return virtblk_fail_to_queue(req, -ENOMEM);
 345
 346         blk_mq_start_request(req);
 347
 348         return BLK_STS_OK;
 349 }
 350
 351 static blk_status_t virtio_queue_rq(struct blk_mq_hw_ctx *hctx,
 352                            const struct blk_mq_queue_data *bd)
 353 {
 354         struct virtio_blk *vblk = hctx->queue->queuedata;
 355         struct request *req = bd->rq;
 356         struct virtblk_req *vbr = blk_mq_rq_to_pdu(req);
 357         unsigned long flags;
 358         int qid = hctx->queue_num;
 359         bool notify = false;
 360         blk_status_t status;
 361         int err;
 362
 363         status = virtblk_prep_rq(hctx, vblk, req, vbr);
 364         if (unlikely(status))
 365                 return status;
 366
 367         spin_lock_irqsave(&vblk->vqs[qid].lock, flags);
 368         err = virtblk_add_req(vblk->vqs[qid].vq, vbr);
 369         if (err) {
 370                 virtqueue_kick(vblk->vqs[qid].vq);
 371                 /* Don't stop the queue if -ENOMEM: we may have failed to
 372                  * bounce the buffer due to global resource outage.
 373                  */
 374                 if (err == -ENOSPC)
 375                         blk_mq_stop_hw_queue(hctx);
 376                 spin_unlock_irqrestore(&vblk->vqs[qid].lock, flags);
 377                 virtblk_unmap_data(req, vbr);
 378                 return virtblk_fail_to_queue(req, err);
 379         }
 380
 381         if (bd->last && virtqueue_kick_prepare(vblk->vqs[qid].vq))
 382                 notify = true;
 383         spin_unlock_irqrestore(&vblk->vqs[qid].lock, flags);
 384
 385         if (notify)
 386                 virtqueue_notify(vblk->vqs[qid].vq);
 387         return BLK_STS_OK;
 388 }
 389
 390 static bool virtblk_prep_rq_batch(struct request *req)
 391 {
 392         struct virtio_blk *vblk = req->mq_hctx->queue->queuedata;
 393         struct virtblk_req *vbr = blk_mq_rq_to_pdu(req);
 394
 395         req->mq_hctx->tags->rqs[req->tag] = req;
 396
 397         return virtblk_prep_rq(req->mq_hctx, vblk, req, vbr) == BLK_STS_OK;
 398 }
 399
 400 static bool virtblk_add_req_batch(struct virtio_blk_vq *vq,
 401                                         struct request **rqlist)
 402 {
 403         unsigned long flags;
 404         int err;
 405         bool kick;
 406
 407         spin_lock_irqsave(&vq->lock, flags);
 408
 409         while (!rq_list_empty(*rqlist)) {
 410                 struct request *req = rq_list_pop(rqlist);
 411                 struct virtblk_req *vbr = blk_mq_rq_to_pdu(req);
 412
 413                 err = virtblk_add_req(vq->vq, vbr);
 414                 if (err) {
 415                         virtblk_unmap_data(req, vbr);
 416                         virtblk_cleanup_cmd(req);
 417                         blk_mq_requeue_request(req, true);
 418                 }
 419         }
 420
 421         kick = virtqueue_kick_prepare(vq->vq);
 422         spin_unlock_irqrestore(&vq->lock, flags);
 423
 424         return kick;
 425 }
 426
 427 static void virtio_queue_rqs(struct request **rqlist)
 428 {
 429         struct request *req, *next, *prev = NULL;
 430         struct request *requeue_list = NULL;
 431
 432         rq_list_for_each_safe(rqlist, req, next) {
 433                 struct virtio_blk_vq *vq = get_virtio_blk_vq(req->mq_hctx);
 434                 bool kick;
 435
 436                 if (!virtblk_prep_rq_batch(req)) {
 437                         rq_list_move(rqlist, &requeue_list, req, prev);
 438                         req = prev;
 439                         if (!req)
 440                                 continue;
 441                 }
 442
 443                 if (!next || req->mq_hctx != next->mq_hctx) {
 444                         req->rq_next = NULL;
 445                         kick = virtblk_add_req_batch(vq, rqlist);
 446                         if (kick)
 447                                 virtqueue_notify(vq->vq);
 448
 449                         *rqlist = next;
 450                         prev = NULL;
 451                 } else
 452                         prev = req;
 453         }
 454
 455         *rqlist = requeue_list;
 456 }
 457
 458 /* return id (s/n) string for *disk to *id_str
 459  */
 460 static int virtblk_get_id(struct gendisk *disk, char *id_str)
 461 {
 462         struct virtio_blk *vblk = disk->private_data;
 463         struct request_queue *q = vblk->disk->queue;
 464         struct request *req;
 465         int err;
 466
 467         req = blk_mq_alloc_request(q, REQ_OP_DRV_IN, 0);
 468         if (IS_ERR(req))
 469                 return PTR_ERR(req);
 470
 471         err = blk_rq_map_kern(q, req, id_str, VIRTIO_BLK_ID_BYTES, GFP_KERNEL);
 472         if (err)
 473                 goto out;
 474
 475         blk_execute_rq(req, false);
 476         err = blk_status_to_errno(virtblk_result(blk_mq_rq_to_pdu(req)));
 477 out:
 478         blk_mq_free_request(req);
 479         return err;
 480 }
 481
 482 /* We provide getgeo only to please some old bootloader/partitioning tools */
 483 static int virtblk_getgeo(struct block_device *bd, struct hd_geometry *geo)
 484 {
 485         struct virtio_blk *vblk = bd->bd_disk->private_data;
 486         int ret = 0;
 487
 488         mutex_lock(&vblk->vdev_mutex);
 489
 490         if (!vblk->vdev) {
 491                 ret = -ENXIO;
 492                 goto out;
 493         }
 494
 495         /* see if the host passed in geometry config */
 496         if (virtio_has_feature(vblk->vdev, VIRTIO_BLK_F_GEOMETRY)) {
 497                 virtio_cread(vblk->vdev, struct virtio_blk_config,
 498                              geometry.cylinders, &geo->cylinders);
 499                 virtio_cread(vblk->vdev, struct virtio_blk_config,
 500                              geometry.heads, &geo->heads);
 501                 virtio_cread(vblk->vdev, struct virtio_blk_config,
 502                              geometry.sectors, &geo->sectors);
 503         } else {
 504                 /* some standard values, similar to sd */
 505                 geo->heads = 1 << 6;
 506                 geo->sectors = 1 << 5;
 507                 geo->cylinders = get_capacity(bd->bd_disk) >> 11;
 508         }
 509 out:
 510         mutex_unlock(&vblk->vdev_mutex);
 511         return ret;
 512 }
 513
 514 static void virtblk_free_disk(struct gendisk *disk)
 515 {
 516         struct virtio_blk *vblk = disk->private_data;
 517
 518         ida_simple_remove(&vd_index_ida, vblk->index);
 519         mutex_destroy(&vblk->vdev_mutex);
 520         kfree(vblk);
 521 }
 522
 523 static const struct block_device_operations virtblk_fops = {
 524         .owner          = THIS_MODULE,
 525         .getgeo         = virtblk_getgeo,
 526         .free_disk      = virtblk_free_disk,
 527 };
 528
 529 static int index_to_minor(int index)
 530 {
 531         return index << PART_BITS;
 532 }
 533
 534 static int minor_to_index(int minor)
 535 {
 536         return minor >> PART_BITS;
 537 }
 538
 539 static ssize_t serial_show(struct device *dev,
 540                            struct device_attribute *attr, char *buf)
 541 {
 542         struct gendisk *disk = dev_to_disk(dev);
 543         int err;
 544
 545         /* sysfs gives us a PAGE_SIZE buffer */
 546         BUILD_BUG_ON(PAGE_SIZE < VIRTIO_BLK_ID_BYTES);
 547
 548         buf[VIRTIO_BLK_ID_BYTES] = '\0';
 549         err = virtblk_get_id(disk, buf);
 550         if (!err)
 551                 return strlen(buf);
 552
 553         if (err == -EIO) /* Unsupported? Make it empty. */
 554                 return 0;
 555
 556         return err;
 557 }
 558
 559 static DEVICE_ATTR_RO(serial);
 560
 561 /* The queue's logical block size must be set before calling this */
 562 static void virtblk_update_capacity(struct virtio_blk *vblk, bool resize)
 563 {
 564         struct virtio_device *vdev = vblk->vdev;
 565         struct request_queue *q = vblk->disk->queue;
 566         char cap_str_2[10], cap_str_10[10];
 567         unsigned long long nblocks;
 568         u64 capacity;
 569
 570         /* Host must always specify the capacity. */
 571         virtio_cread(vdev, struct virtio_blk_config, capacity, &capacity);
 572
 573         nblocks = DIV_ROUND_UP_ULL(capacity, queue_logical_block_size(q) >> 9);
 574
 575         string_get_size(nblocks, queue_logical_block_size(q),
 576                         STRING_UNITS_2, cap_str_2, sizeof(cap_str_2));
 577         string_get_size(nblocks, queue_logical_block_size(q),
 578                         STRING_UNITS_10, cap_str_10, sizeof(cap_str_10));
 579
 580         dev_notice(&vdev->dev,
 581                    "[%s] %s%llu %d-byte logical blocks (%s/%s)\n",
 582                    vblk->disk->disk_name,
 583                    resize ? "new size: " : "",
 584                    nblocks,
 585                    queue_logical_block_size(q),
 586                    cap_str_10,
 587                    cap_str_2);
 588
 589         set_capacity_and_notify(vblk->disk, capacity);
 590 }
 591
 592 static void virtblk_config_changed_work(struct work_struct *work)
 593 {
 594         struct virtio_blk *vblk =
 595                 container_of(work, struct virtio_blk, config_work);
 596
 597         virtblk_update_capacity(vblk, true);
 598 }
 599
 600 static void virtblk_config_changed(struct virtio_device *vdev)
 601 {
 602         struct virtio_blk *vblk = vdev->priv;
 603
 604         queue_work(virtblk_wq, &vblk->config_work);
 605 }
 606
 607 static int init_vq(struct virtio_blk *vblk)
 608 {
 609         int err;
 610         int i;
 611         vq_callback_t **callbacks;
 612         const char **names;
 613         struct virtqueue **vqs;
 614         unsigned short num_vqs;
 615         unsigned int num_poll_vqs;
 616         struct virtio_device *vdev = vblk->vdev;
 617         struct irq_affinity desc = { 0, };
 618
 619         err = virtio_cread_feature(vdev, VIRTIO_BLK_F_MQ,
 620                                    struct virtio_blk_config, num_queues,
 621                                    &num_vqs);
 622         if (err)
 623                 num_vqs = 1;
 624
 625         if (!err && !num_vqs) {
 626                 dev_err(&vdev->dev, "MQ advertised but zero queues reported\n");
 627                 return -EINVAL;
 628         }
 629
 630         num_vqs = min_t(unsigned int,
 631                         min_not_zero(num_request_queues, nr_cpu_ids),
 632                         num_vqs);
 633
 634         num_poll_vqs = min_t(unsigned int, poll_queues, num_vqs - 1);
 635
 636         vblk->io_queues[HCTX_TYPE_DEFAULT] = num_vqs - num_poll_vqs;
 637         vblk->io_queues[HCTX_TYPE_READ] = 0;
 638         vblk->io_queues[HCTX_TYPE_POLL] = num_poll_vqs;
 639
 640         dev_info(&vdev->dev, "%d/%d/%d default/read/poll queues\n",
 641                                 vblk->io_queues[HCTX_TYPE_DEFAULT],
 642                                 vblk->io_queues[HCTX_TYPE_READ],
 643                                 vblk->io_queues[HCTX_TYPE_POLL]);
 644
 645         vblk->vqs = kmalloc_array(num_vqs, sizeof(*vblk->vqs), GFP_KERNEL);
 646         if (!vblk->vqs)
 647                 return -ENOMEM;
 648
 649         names = kmalloc_array(num_vqs, sizeof(*names), GFP_KERNEL);
 650         callbacks = kmalloc_array(num_vqs, sizeof(*callbacks), GFP_KERNEL);
 651         vqs = kmalloc_array(num_vqs, sizeof(*vqs), GFP_KERNEL);
 652         if (!names || !callbacks || !vqs) {
 653                 err = -ENOMEM;
 654                 goto out;
 655         }
 656
 657         for (i = 0; i < num_vqs - num_poll_vqs; i++) {
 658                 callbacks[i] = virtblk_done;
 659                 snprintf(vblk->vqs[i].name, VQ_NAME_LEN, "req.%d", i);
 660                 names[i] = vblk->vqs[i].name;
 661         }
 662
 663         for (; i < num_vqs; i++) {
 664                 callbacks[i] = NULL;
 665                 snprintf(vblk->vqs[i].name, VQ_NAME_LEN, "req_poll.%d", i);
 666                 names[i] = vblk->vqs[i].name;
 667         }
 668
 669         /* Discover virtqueues and write information to configuration.  */
 670         err = virtio_find_vqs(vdev, num_vqs, vqs, callbacks, names, &desc);
 671         if (err)
 672                 goto out;
 673
 674         for (i = 0; i < num_vqs; i++) {
 675                 spin_lock_init(&vblk->vqs[i].lock);
 676                 vblk->vqs[i].vq = vqs[i];
 677         }
 678         vblk->num_vqs = num_vqs;
 679
 680 out:
 681         kfree(vqs);
 682         kfree(callbacks);
 683         kfree(names);
 684         if (err)
 685                 kfree(vblk->vqs);
 686         return err;
 687 }
 688
 689 /*
 690  * Legacy naming scheme used for virtio devices.  We are stuck with it for
 691  * virtio blk but don't ever use it for any new driver.
 692  */
 693 static int virtblk_name_format(char *prefix, int index, char *buf, int buflen)
 694 {
 695         const int base = 'z' - 'a' + 1;
 696         char *begin = buf + strlen(prefix);
 697         char *end = buf + buflen;
 698         char *p;
 699         int unit;
 700
 701         p = end - 1;
 702         *p = '\0';
 703         unit = base;
 704         do {
 705                 if (p == begin)
 706                         return -EINVAL;
 707                 *--p = 'a' + (index % unit);
 708                 index = (index / unit) - 1;
 709         } while (index >= 0);
 710
 711         memmove(begin, p, end - p);
 712         memcpy(buf, prefix, strlen(prefix));
 713
 714         return 0;
 715 }
 716
 717 static int virtblk_get_cache_mode(struct virtio_device *vdev)
 718 {
 719         u8 writeback;
 720         int err;
 721
 722         err = virtio_cread_feature(vdev, VIRTIO_BLK_F_CONFIG_WCE,
 723                                    struct virtio_blk_config, wce,
 724                                    &writeback);
 725
 726         /*
 727          * If WCE is not configurable and flush is not available,
 728          * assume no writeback cache is in use.
 729          */
 730         if (err)
 731                 writeback = virtio_has_feature(vdev, VIRTIO_BLK_F_FLUSH);
 732
 733         return writeback;
 734 }
 735
 736 static void virtblk_update_cache_mode(struct virtio_device *vdev)
 737 {
 738         u8 writeback = virtblk_get_cache_mode(vdev);
 739         struct virtio_blk *vblk = vdev->priv;
 740
 741         blk_queue_write_cache(vblk->disk->queue, writeback, false);
 742 }
 743
 744 static const char *const virtblk_cache_types[] = {
 745         "write through", "write back"
 746 };
 747
 748 static ssize_t
 749 cache_type_store(struct device *dev, struct device_attribute *attr,
 750                  const char *buf, size_t count)
 751 {
 752         struct gendisk *disk = dev_to_disk(dev);
 753         struct virtio_blk *vblk = disk->private_data;
 754         struct virtio_device *vdev = vblk->vdev;
 755         int i;
 756
 757         BUG_ON(!virtio_has_feature(vblk->vdev, VIRTIO_BLK_F_CONFIG_WCE));
 758         i = sysfs_match_string(virtblk_cache_types, buf);
 759         if (i < 0)
 760                 return i;
 761
 762         virtio_cwrite8(vdev, offsetof(struct virtio_blk_config, wce), i);
 763         virtblk_update_cache_mode(vdev);
 764         return count;
 765 }
 766
 767 static ssize_t
 768 cache_type_show(struct device *dev, struct device_attribute *attr, char *buf)
 769 {
 770         struct gendisk *disk = dev_to_disk(dev);
 771         struct virtio_blk *vblk = disk->private_data;
 772         u8 writeback = virtblk_get_cache_mode(vblk->vdev);
 773
 774         BUG_ON(writeback >= ARRAY_SIZE(virtblk_cache_types));
 775         return sysfs_emit(buf, "%s\n", virtblk_cache_types[writeback]);
 776 }
 777
 778 static DEVICE_ATTR_RW(cache_type);
 779
 780 static struct attribute *virtblk_attrs[] = {
 781         &dev_attr_serial.attr,
 782         &dev_attr_cache_type.attr,
 783         NULL,
 784 };
 785
 786 static umode_t virtblk_attrs_are_visible(struct kobject *kobj,
 787                 struct attribute *a, int n)
 788 {
 789         struct device *dev = kobj_to_dev(kobj);
 790         struct gendisk *disk = dev_to_disk(dev);
 791         struct virtio_blk *vblk = disk->private_data;
 792         struct virtio_device *vdev = vblk->vdev;
 793
 794         if (a == &dev_attr_cache_type.attr &&
 795             !virtio_has_feature(vdev, VIRTIO_BLK_F_CONFIG_WCE))
 796                 return S_IRUGO;
 797
 798         return a->mode;
 799 }
 800
 801 static const struct attribute_group virtblk_attr_group = {
 802         .attrs = virtblk_attrs,
 803         .is_visible = virtblk_attrs_are_visible,
 804 };
 805
 806 static const struct attribute_group *virtblk_attr_groups[] = {
 807         &virtblk_attr_group,
 808         NULL,
 809 };
 810
 811 static void virtblk_map_queues(struct blk_mq_tag_set *set)
 812 {
 813         struct virtio_blk *vblk = set->driver_data;
 814         int i, qoff;
 815
 816         for (i = 0, qoff = 0; i < set->nr_maps; i++) {
 817                 struct blk_mq_queue_map *map = &set->map[i];
 818
 819                 map->nr_queues = vblk->io_queues[i];
 820                 map->queue_offset = qoff;
 821                 qoff += map->nr_queues;
 822
 823                 if (map->nr_queues == 0)
 824                         continue;
 825
 826                 /*
 827                  * Regular queues have interrupts and hence CPU affinity is
 828                  * defined by the core virtio code, but polling queues have
 829                  * no interrupts so we let the block layer assign CPU affinity.
 830                  */
 831                 if (i == HCTX_TYPE_POLL)
 832                         blk_mq_map_queues(&set->map[i]);
 833                 else
 834                         blk_mq_virtio_map_queues(&set->map[i], vblk->vdev, 0);
 835         }
 836 }
 837
 838 static void virtblk_complete_batch(struct io_comp_batch *iob)
 839 {
 840         struct request *req;
 841
 842         rq_list_for_each(&iob->req_list, req) {
 843                 virtblk_unmap_data(req, blk_mq_rq_to_pdu(req));
 844                 virtblk_cleanup_cmd(req);
 845         }
 846         blk_mq_end_request_batch(iob);
 847 }
 848
 849 static int virtblk_poll(struct blk_mq_hw_ctx *hctx, struct io_comp_batch *iob)
 850 {
 851         struct virtio_blk *vblk = hctx->queue->queuedata;
 852         struct virtio_blk_vq *vq = get_virtio_blk_vq(hctx);
 853         struct virtblk_req *vbr;
 854         unsigned long flags;
 855         unsigned int len;
 856         int found = 0;
 857
 858         spin_lock_irqsave(&vq->lock, flags);
 859
 860         while ((vbr = virtqueue_get_buf(vq->vq, &len)) != NULL) {
 861                 struct request *req = blk_mq_rq_from_pdu(vbr);
 862
 863                 found++;
 864                 if (!blk_mq_add_to_batch(req, iob, vbr->status,
 865                                                 virtblk_complete_batch))
 866                         blk_mq_complete_request(req);
 867         }
 868
 869         if (found)
 870                 blk_mq_start_stopped_hw_queues(vblk->disk->queue, true);
 871
 872         spin_unlock_irqrestore(&vq->lock, flags);
 873
 874         return found;
 875 }
 876
 877 static const struct blk_mq_ops virtio_mq_ops = {
 878         .queue_rq       = virtio_queue_rq,
 879         .queue_rqs      = virtio_queue_rqs,
 880         .commit_rqs     = virtio_commit_rqs,
 881         .complete       = virtblk_request_done,
 882         .map_queues     = virtblk_map_queues,
 883         .poll           = virtblk_poll,
 884 };
 885
 886 static unsigned int virtblk_queue_depth;
 887 module_param_named(queue_depth, virtblk_queue_depth, uint, 0444);
 888
 889 static int virtblk_probe(struct virtio_device *vdev)
 890 {
 891         struct virtio_blk *vblk;
 892         struct request_queue *q;
 893         int err, index;
 894
 895         u32 v, blk_size, max_size, sg_elems, opt_io_size;
 896         u32 max_discard_segs = 0;
 897         u32 discard_granularity = 0;
 898         u16 min_io_size;
 899         u8 physical_block_exp, alignment_offset;
 900         unsigned int queue_depth;
 901
 902         if (!vdev->config->get) {
 903                 dev_err(&vdev->dev, "%s failure: config access disabled\n",
 904                         __func__);
 905                 return -EINVAL;
 906         }
 907
 908         err = ida_simple_get(&vd_index_ida, 0, minor_to_index(1 << MINORBITS),
 909                              GFP_KERNEL);
 910         if (err < 0)
 911                 goto out;
 912         index = err;
 913
 914         /* We need to know how many segments before we allocate. */
 915         err = virtio_cread_feature(vdev, VIRTIO_BLK_F_SEG_MAX,
 916                                    struct virtio_blk_config, seg_max,
 917                                    &sg_elems);
 918
 919         /* We need at least one SG element, whatever they say. */
 920         if (err || !sg_elems)
 921                 sg_elems = 1;
 922
 923         /* Prevent integer overflows and honor max vq size */
 924         sg_elems = min_t(u32, sg_elems, VIRTIO_BLK_MAX_SG_ELEMS - 2);
 925
 926         vdev->priv = vblk = kmalloc(sizeof(*vblk), GFP_KERNEL);
 927         if (!vblk) {
 928                 err = -ENOMEM;
 929                 goto out_free_index;
 930         }
 931
 932         mutex_init(&vblk->vdev_mutex);
 933
 934         vblk->vdev = vdev;
 935
 936         INIT_WORK(&vblk->config_work, virtblk_config_changed_work);
 937
 938         err = init_vq(vblk);
 939         if (err)
 940                 goto out_free_vblk;
 941
 942         /* Default queue sizing is to fill the ring. */
 943         if (!virtblk_queue_depth) {
 944                 queue_depth = vblk->vqs[0].vq->num_free;
 945                 /* ... but without indirect descs, we use 2 descs per req */
 946                 if (!virtio_has_feature(vdev, VIRTIO_RING_F_INDIRECT_DESC))
 947                         queue_depth /= 2;
 948         } else {
 949                 queue_depth = virtblk_queue_depth;
 950         }
 951
 952         memset(&vblk->tag_set, 0, sizeof(vblk->tag_set));
 953         vblk->tag_set.ops = &virtio_mq_ops;
 954         vblk->tag_set.queue_depth = queue_depth;
 955         vblk->tag_set.numa_node = NUMA_NO_NODE;
 956         vblk->tag_set.flags = BLK_MQ_F_SHOULD_MERGE;
 957         vblk->tag_set.cmd_size =
 958                 sizeof(struct virtblk_req) +
 959                 sizeof(struct scatterlist) * VIRTIO_BLK_INLINE_SG_CNT;
 960         vblk->tag_set.driver_data = vblk;
 961         vblk->tag_set.nr_hw_queues = vblk->num_vqs;
 962         vblk->tag_set.nr_maps = 1;
 963         if (vblk->io_queues[HCTX_TYPE_POLL])
 964                 vblk->tag_set.nr_maps = 3;
 965
 966         err = blk_mq_alloc_tag_set(&vblk->tag_set);
 967         if (err)
 968                 goto out_free_vq;
 969
 970         vblk->disk = blk_mq_alloc_disk(&vblk->tag_set, vblk);
 971         if (IS_ERR(vblk->disk)) {
 972                 err = PTR_ERR(vblk->disk);
 973                 goto out_free_tags;
 974         }
 975         q = vblk->disk->queue;
 976
 977         virtblk_name_format("vd", index, vblk->disk->disk_name, DISK_NAME_LEN);
 978
 979         vblk->disk->major = major;
 980         vblk->disk->first_minor = index_to_minor(index);
 981         vblk->disk->minors = 1 << PART_BITS;
 982         vblk->disk->private_data = vblk;
 983         vblk->disk->fops = &virtblk_fops;
 984         vblk->index = index;
 985
 986         /* configure queue flush support */
 987         virtblk_update_cache_mode(vdev);
 988
 989         /* If disk is read-only in the host, the guest should obey */
 990         if (virtio_has_feature(vdev, VIRTIO_BLK_F_RO))
 991                 set_disk_ro(vblk->disk, 1);
 992
 993         /* We can handle whatever the host told us to handle. */
 994         blk_queue_max_segments(q, sg_elems);
 995
 996         /* No real sector limit. */
 997         blk_queue_max_hw_sectors(q, -1U);
 998
 999         max_size = virtio_max_dma_size(vdev);
1000
1001         /* Host can optionally specify maximum segment size and number of
1002          * segments. */
1003         err = virtio_cread_feature(vdev, VIRTIO_BLK_F_SIZE_MAX,
1004                                    struct virtio_blk_config, size_max, &v);
1005         if (!err)
1006                 max_size = min(max_size, v);
1007
1008         blk_queue_max_segment_size(q, max_size);
1009
1010         /* Host can optionally specify the block size of the device */
1011         err = virtio_cread_feature(vdev, VIRTIO_BLK_F_BLK_SIZE,
1012                                    struct virtio_blk_config, blk_size,
1013                                    &blk_size);
1014         if (!err) {
1015                 err = blk_validate_block_size(blk_size);
1016                 if (err) {
1017                         dev_err(&vdev->dev,
1018                                 "virtio_blk: invalid block size: 0x%x\n",
1019                                 blk_size);
1020                         goto out_cleanup_disk;
1021                 }
1022
1023                 blk_queue_logical_block_size(q, blk_size);
1024         } else
1025                 blk_size = queue_logical_block_size(q);
1026
1027         /* Use topology information if available */
1028         err = virtio_cread_feature(vdev, VIRTIO_BLK_F_TOPOLOGY,
1029                                    struct virtio_blk_config, physical_block_exp,
1030                                    &physical_block_exp);
1031         if (!err && physical_block_exp)
1032                 blk_queue_physical_block_size(q,
1033                                 blk_size * (1 << physical_block_exp));
1034
1035         err = virtio_cread_feature(vdev, VIRTIO_BLK_F_TOPOLOGY,
1036                                    struct virtio_blk_config, alignment_offset,
1037                                    &alignment_offset);
1038         if (!err && alignment_offset)
1039                 blk_queue_alignment_offset(q, blk_size * alignment_offset);
1040
1041         err = virtio_cread_feature(vdev, VIRTIO_BLK_F_TOPOLOGY,
1042                                    struct virtio_blk_config, min_io_size,
1043                                    &min_io_size);
1044         if (!err && min_io_size)
1045                 blk_queue_io_min(q, blk_size * min_io_size);
1046
1047         err = virtio_cread_feature(vdev, VIRTIO_BLK_F_TOPOLOGY,
1048                                    struct virtio_blk_config, opt_io_size,
1049                                    &opt_io_size);
1050         if (!err && opt_io_size)
1051                 blk_queue_io_opt(q, blk_size * opt_io_size);
1052
1053         if (virtio_has_feature(vdev, VIRTIO_BLK_F_DISCARD)) {
1054                 virtio_cread(vdev, struct virtio_blk_config,
1055                              discard_sector_alignment, &discard_granularity);
1056
1057                 virtio_cread(vdev, struct virtio_blk_config,
1058                              max_discard_sectors, &v);
1059                 blk_queue_max_discard_sectors(q, v ? v : UINT_MAX);
1060
1061                 virtio_cread(vdev, struct virtio_blk_config, max_discard_seg,
1062                              &max_discard_segs);
1063         }
1064
1065         if (virtio_has_feature(vdev, VIRTIO_BLK_F_WRITE_ZEROES)) {
1066                 virtio_cread(vdev, struct virtio_blk_config,
1067                              max_write_zeroes_sectors, &v);
1068                 blk_queue_max_write_zeroes_sectors(q, v ? v : UINT_MAX);
1069         }
1070
1071         /* The discard and secure erase limits are combined since the Linux
1072          * block layer uses the same limit for both commands.
1073          *
1074          * If both VIRTIO_BLK_F_SECURE_ERASE and VIRTIO_BLK_F_DISCARD features
1075          * are negotiated, we will use the minimum between the limits.
1076          *
1077          * discard sector alignment is set to the minimum between discard_sector_alignment
1078          * and secure_erase_sector_alignment.
1079          *
1080          * max discard sectors is set to the minimum between max_discard_seg and
1081          * max_secure_erase_seg.
1082          */
1083         if (virtio_has_feature(vdev, VIRTIO_BLK_F_SECURE_ERASE)) {
1084
1085                 virtio_cread(vdev, struct virtio_blk_config,
1086                              secure_erase_sector_alignment, &v);
1087
1088                 /* secure_erase_sector_alignment should not be zero, the device should set a
1089                  * valid number of sectors.
1090                  */
1091                 if (!v) {
1092                         dev_err(&vdev->dev,
1093                                 "virtio_blk: secure_erase_sector_alignment can't be 0\n");
1094                         err = -EINVAL;
1095                         goto out_cleanup_disk;
1096                 }
1097
1098                 discard_granularity = min_not_zero(discard_granularity, v);
1099
1100                 virtio_cread(vdev, struct virtio_blk_config,
1101                              max_secure_erase_sectors, &v);
1102
1103                 /* max_secure_erase_sectors should not be zero, the device should set a
1104                  * valid number of sectors.
1105                  */
1106                 if (!v) {
1107                         dev_err(&vdev->dev,
1108                                 "virtio_blk: max_secure_erase_sectors can't be 0\n");
1109                         err = -EINVAL;
1110                         goto out_cleanup_disk;
1111                 }
1112
1113                 blk_queue_max_secure_erase_sectors(q, v);
1114
1115                 virtio_cread(vdev, struct virtio_blk_config,
1116                              max_secure_erase_seg, &v);
1117
1118                 /* max_secure_erase_seg should not be zero, the device should set a
1119                  * valid number of segments
1120                  */
1121                 if (!v) {
1122                         dev_err(&vdev->dev,
1123                                 "virtio_blk: max_secure_erase_seg can't be 0\n");
1124                         err = -EINVAL;
1125                         goto out_cleanup_disk;
1126                 }
1127
1128                 max_discard_segs = min_not_zero(max_discard_segs, v);
1129         }
1130
1131         if (virtio_has_feature(vdev, VIRTIO_BLK_F_DISCARD) ||
1132             virtio_has_feature(vdev, VIRTIO_BLK_F_SECURE_ERASE)) {
1133                 /* max_discard_seg and discard_granularity will be 0 only
1134                  * if max_discard_seg and discard_sector_alignment fields in the virtio
1135                  * config are 0 and VIRTIO_BLK_F_SECURE_ERASE feature is not negotiated.
1136                  * In this case, we use default values.
1137                  */
1138                 if (!max_discard_segs)
1139                         max_discard_segs = sg_elems;
1140
1141                 blk_queue_max_discard_segments(q,
1142                                                min(max_discard_segs, MAX_DISCARD_SEGMENTS));
1143
1144                 if (discard_granularity)
1145                         q->limits.discard_granularity = discard_granularity << SECTOR_SHIFT;
1146                 else
1147                         q->limits.discard_granularity = blk_size;
1148         }
1149
1150         virtblk_update_capacity(vblk, false);
1151         virtio_device_ready(vdev);
1152
1153         err = device_add_disk(&vdev->dev, vblk->disk, virtblk_attr_groups);
1154         if (err)
1155                 goto out_cleanup_disk;
1156
1157         return 0;
1158
1159 out_cleanup_disk:
1160         put_disk(vblk->disk);
1161 out_free_tags:
1162         blk_mq_free_tag_set(&vblk->tag_set);
1163 out_free_vq:
1164         vdev->config->del_vqs(vdev);
1165         kfree(vblk->vqs);
1166 out_free_vblk:
1167         kfree(vblk);
1168 out_free_index:
1169         ida_simple_remove(&vd_index_ida, index);
1170 out:
1171         return err;
1172 }
1173
1174 static void virtblk_remove(struct virtio_device *vdev)
1175 {
1176         struct virtio_blk *vblk = vdev->priv;
1177
1178         /* Make sure no work handler is accessing the device. */
1179         flush_work(&vblk->config_work);
1180
1181         del_gendisk(vblk->disk);
1182         blk_mq_free_tag_set(&vblk->tag_set);
1183
1184         mutex_lock(&vblk->vdev_mutex);
1185
1186         /* Stop all the virtqueues. */
1187         virtio_reset_device(vdev);
1188
1189         /* Virtqueues are stopped, nothing can use vblk->vdev anymore. */
1190         vblk->vdev = NULL;
1191
1192         vdev->config->del_vqs(vdev);
1193         kfree(vblk->vqs);
1194
1195         mutex_unlock(&vblk->vdev_mutex);
1196
1197         put_disk(vblk->disk);
1198 }
1199
1200 #ifdef CONFIG_PM_SLEEP
1201 static int virtblk_freeze(struct virtio_device *vdev)
1202 {
1203         struct virtio_blk *vblk = vdev->priv;
1204
1205         /* Ensure we don't receive any more interrupts */
1206         virtio_reset_device(vdev);
1207
1208         /* Make sure no work handler is accessing the device. */
1209         flush_work(&vblk->config_work);
1210
1211         blk_mq_quiesce_queue(vblk->disk->queue);
1212
1213         vdev->config->del_vqs(vdev);
1214         kfree(vblk->vqs);
1215
1216         return 0;
1217 }
1218
1219 static int virtblk_restore(struct virtio_device *vdev)
1220 {
1221         struct virtio_blk *vblk = vdev->priv;
1222         int ret;
1223
1224         ret = init_vq(vdev->priv);
1225         if (ret)
1226                 return ret;
1227
1228         virtio_device_ready(vdev);
1229
1230         blk_mq_unquiesce_queue(vblk->disk->queue);
1231         return 0;
1232 }
1233 #endif
1234
1235 static const struct virtio_device_id id_table[] = {
1236         { VIRTIO_ID_BLOCK, VIRTIO_DEV_ANY_ID },
1237         { 0 },
1238 };
1239
1240 static unsigned int features_legacy[] = {
1241         VIRTIO_BLK_F_SEG_MAX, VIRTIO_BLK_F_SIZE_MAX, VIRTIO_BLK_F_GEOMETRY,
1242         VIRTIO_BLK_F_RO, VIRTIO_BLK_F_BLK_SIZE,
1243         VIRTIO_BLK_F_FLUSH, VIRTIO_BLK_F_TOPOLOGY, VIRTIO_BLK_F_CONFIG_WCE,
1244         VIRTIO_BLK_F_MQ, VIRTIO_BLK_F_DISCARD, VIRTIO_BLK_F_WRITE_ZEROES,
1245         VIRTIO_BLK_F_SECURE_ERASE,
1246 }
1247 ;
1248 static unsigned int features[] = {
1249         VIRTIO_BLK_F_SEG_MAX, VIRTIO_BLK_F_SIZE_MAX, VIRTIO_BLK_F_GEOMETRY,
1250         VIRTIO_BLK_F_RO, VIRTIO_BLK_F_BLK_SIZE,
1251         VIRTIO_BLK_F_FLUSH, VIRTIO_BLK_F_TOPOLOGY, VIRTIO_BLK_F_CONFIG_WCE,
1252         VIRTIO_BLK_F_MQ, VIRTIO_BLK_F_DISCARD, VIRTIO_BLK_F_WRITE_ZEROES,
1253         VIRTIO_BLK_F_SECURE_ERASE,
1254 };
1255
1256 static struct virtio_driver virtio_blk = {
1257         .feature_table                  = features,
1258         .feature_table_size             = ARRAY_SIZE(features),
1259         .feature_table_legacy           = features_legacy,
1260         .feature_table_size_legacy      = ARRAY_SIZE(features_legacy),
1261         .driver.name                    = KBUILD_MODNAME,
1262         .driver.owner                   = THIS_MODULE,
1263         .id_table                       = id_table,
1264         .probe                          = virtblk_probe,
1265         .remove                         = virtblk_remove,
1266         .config_changed                 = virtblk_config_changed,
1267 #ifdef CONFIG_PM_SLEEP
1268         .freeze                         = virtblk_freeze,
1269         .restore                        = virtblk_restore,
1270 #endif
1271 };
1272
1273 static int __init virtio_blk_init(void)
1274 {
1275         int error;
1276
1277         virtblk_wq = alloc_workqueue("virtio-blk", 0, 0);
1278         if (!virtblk_wq)
1279                 return -ENOMEM;
1280
1281         major = register_blkdev(0, "virtblk");
1282         if (major < 0) {
1283                 error = major;
1284                 goto out_destroy_workqueue;
1285         }
1286
1287         error = register_virtio_driver(&virtio_blk);
1288         if (error)
1289                 goto out_unregister_blkdev;
1290         return 0;
1291
1292 out_unregister_blkdev:
1293         unregister_blkdev(major, "virtblk");
1294 out_destroy_workqueue:
1295         destroy_workqueue(virtblk_wq);
1296         return error;
1297 }
1298
1299 static void __exit virtio_blk_fini(void)
1300 {
1301         unregister_virtio_driver(&virtio_blk);
1302         unregister_blkdev(major, "virtblk");
1303         destroy_workqueue(virtblk_wq);
1304 }
1305 module_init(virtio_blk_init);
1306 module_exit(virtio_blk_fini);
1307
1308 MODULE_DEVICE_TABLE(virtio, id_table);
1309 MODULE_DESCRIPTION("Virtio block driver");
1310 MODULE_LICENSE("GPL");