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 <linux/vmalloc.h>
  19 #include <uapi/linux/virtio_ring.h>
  20
  21 #define PART_BITS 4
  22 #define VQ_NAME_LEN 16
  23 #define MAX_DISCARD_SEGMENTS 256u
  24
  25 /* The maximum number of sg elements that fit into a virtqueue */
  26 #define VIRTIO_BLK_MAX_SG_ELEMS 32768
  27
  28 #ifdef CONFIG_ARCH_NO_SG_CHAIN
  29 #define VIRTIO_BLK_INLINE_SG_CNT        0
  30 #else
  31 #define VIRTIO_BLK_INLINE_SG_CNT        2
  32 #endif
  33
  34 static unsigned int num_request_queues;
  35 module_param(num_request_queues, uint, 0644);
  36 MODULE_PARM_DESC(num_request_queues,
  37                  "Limit the number of request queues to use for blk device. "
  38                  "0 for no limit. "
  39                  "Values > nr_cpu_ids truncated to nr_cpu_ids.");
  40
  41 static unsigned int poll_queues;
  42 module_param(poll_queues, uint, 0644);
  43 MODULE_PARM_DESC(poll_queues, "The number of dedicated virtqueues for polling I/O");
  44
  45 static int major;
  46 static DEFINE_IDA(vd_index_ida);
  47
  48 static struct workqueue_struct *virtblk_wq;
  49
  50 struct virtio_blk_vq {
  51         struct virtqueue *vq;
  52         spinlock_t lock;
  53         char name[VQ_NAME_LEN];
  54 } ____cacheline_aligned_in_smp;
  55
  56 struct virtio_blk {
  57         /*
  58          * This mutex must be held by anything that may run after
  59          * virtblk_remove() sets vblk->vdev to NULL.
  60          *
  61          * blk-mq, virtqueue processing, and sysfs attribute code paths are
  62          * shut down before vblk->vdev is set to NULL and therefore do not need
  63          * to hold this mutex.
  64          */
  65         struct mutex vdev_mutex;
  66         struct virtio_device *vdev;
  67
  68         /* The disk structure for the kernel. */
  69         struct gendisk *disk;
  70
  71         /* Block layer tags. */
  72         struct blk_mq_tag_set tag_set;
  73
  74         /* Process context for config space updates */
  75         struct work_struct config_work;
  76
  77         /* Ida index - used to track minor number allocations. */
  78         int index;
  79
  80         /* num of vqs */
  81         int num_vqs;
  82         int io_queues[HCTX_MAX_TYPES];
  83         struct virtio_blk_vq *vqs;
  84
  85         /* For zoned device */
  86         unsigned int zone_sectors;
  87 };
  88
  89 struct virtblk_req {
  90         /* Out header */
  91         struct virtio_blk_outhdr out_hdr;
  92
  93         /* In header */
  94         union {
  95                 u8 status;
  96
  97                 /*
  98                  * The zone append command has an extended in header.
  99                  * The status field in zone_append_in_hdr must always
 100                  * be the last byte.
 101                  */
 102                 struct {
 103                         __virtio64 sector;
 104                         u8 status;
 105                 } zone_append;
 106         } in_hdr;
 107
 108         size_t in_hdr_len;
 109
 110         struct sg_table sg_table;
 111         struct scatterlist sg[];
 112 };
 113
 114 static inline blk_status_t virtblk_result(u8 status)
 115 {
 116         switch (status) {
 117         case VIRTIO_BLK_S_OK:
 118                 return BLK_STS_OK;
 119         case VIRTIO_BLK_S_UNSUPP:
 120                 return BLK_STS_NOTSUPP;
 121         case VIRTIO_BLK_S_ZONE_OPEN_RESOURCE:
 122                 return BLK_STS_ZONE_OPEN_RESOURCE;
 123         case VIRTIO_BLK_S_ZONE_ACTIVE_RESOURCE:
 124                 return BLK_STS_ZONE_ACTIVE_RESOURCE;
 125         case VIRTIO_BLK_S_IOERR:
 126         case VIRTIO_BLK_S_ZONE_UNALIGNED_WP:
 127         default:
 128                 return BLK_STS_IOERR;
 129         }
 130 }
 131
 132 static inline struct virtio_blk_vq *get_virtio_blk_vq(struct blk_mq_hw_ctx *hctx)
 133 {
 134         struct virtio_blk *vblk = hctx->queue->queuedata;
 135         struct virtio_blk_vq *vq = &vblk->vqs[hctx->queue_num];
 136
 137         return vq;
 138 }
 139
 140 static int virtblk_add_req(struct virtqueue *vq, struct virtblk_req *vbr)
 141 {
 142         struct scatterlist out_hdr, in_hdr, *sgs[3];
 143         unsigned int num_out = 0, num_in = 0;
 144
 145         sg_init_one(&out_hdr, &vbr->out_hdr, sizeof(vbr->out_hdr));
 146         sgs[num_out++] = &out_hdr;
 147
 148         if (vbr->sg_table.nents) {
 149                 if (vbr->out_hdr.type & cpu_to_virtio32(vq->vdev, VIRTIO_BLK_T_OUT))
 150                         sgs[num_out++] = vbr->sg_table.sgl;
 151                 else
 152                         sgs[num_out + num_in++] = vbr->sg_table.sgl;
 153         }
 154
 155         sg_init_one(&in_hdr, &vbr->in_hdr.status, vbr->in_hdr_len);
 156         sgs[num_out + num_in++] = &in_hdr;
 157
 158         return virtqueue_add_sgs(vq, sgs, num_out, num_in, vbr, GFP_ATOMIC);
 159 }
 160
 161 static int virtblk_setup_discard_write_zeroes_erase(struct request *req, bool unmap)
 162 {
 163         unsigned short segments = blk_rq_nr_discard_segments(req);
 164         unsigned short n = 0;
 165         struct virtio_blk_discard_write_zeroes *range;
 166         struct bio *bio;
 167         u32 flags = 0;
 168
 169         if (unmap)
 170                 flags |= VIRTIO_BLK_WRITE_ZEROES_FLAG_UNMAP;
 171
 172         range = kmalloc_array(segments, sizeof(*range), GFP_ATOMIC);
 173         if (!range)
 174                 return -ENOMEM;
 175
 176         /*
 177          * Single max discard segment means multi-range discard isn't
 178          * supported, and block layer only runs contiguity merge like
 179          * normal RW request. So we can't reply on bio for retrieving
 180          * each range info.
 181          */
 182         if (queue_max_discard_segments(req->q) == 1) {
 183                 range[0].flags = cpu_to_le32(flags);
 184                 range[0].num_sectors = cpu_to_le32(blk_rq_sectors(req));
 185                 range[0].sector = cpu_to_le64(blk_rq_pos(req));
 186                 n = 1;
 187         } else {
 188                 __rq_for_each_bio(bio, req) {
 189                         u64 sector = bio->bi_iter.bi_sector;
 190                         u32 num_sectors = bio->bi_iter.bi_size >> SECTOR_SHIFT;
 191
 192                         range[n].flags = cpu_to_le32(flags);
 193                         range[n].num_sectors = cpu_to_le32(num_sectors);
 194                         range[n].sector = cpu_to_le64(sector);
 195                         n++;
 196                 }
 197         }
 198
 199         WARN_ON_ONCE(n != segments);
 200
 201         bvec_set_virt(&req->special_vec, range, sizeof(*range) * segments);
 202         req->rq_flags |= RQF_SPECIAL_PAYLOAD;
 203
 204         return 0;
 205 }
 206
 207 static void virtblk_unmap_data(struct request *req, struct virtblk_req *vbr)
 208 {
 209         if (blk_rq_nr_phys_segments(req))
 210                 sg_free_table_chained(&vbr->sg_table,
 211                                       VIRTIO_BLK_INLINE_SG_CNT);
 212 }
 213
 214 static int virtblk_map_data(struct blk_mq_hw_ctx *hctx, struct request *req,
 215                 struct virtblk_req *vbr)
 216 {
 217         int err;
 218
 219         if (!blk_rq_nr_phys_segments(req))
 220                 return 0;
 221
 222         vbr->sg_table.sgl = vbr->sg;
 223         err = sg_alloc_table_chained(&vbr->sg_table,
 224                                      blk_rq_nr_phys_segments(req),
 225                                      vbr->sg_table.sgl,
 226                                      VIRTIO_BLK_INLINE_SG_CNT);
 227         if (unlikely(err))
 228                 return -ENOMEM;
 229
 230         return blk_rq_map_sg(hctx->queue, req, vbr->sg_table.sgl);
 231 }
 232
 233 static void virtblk_cleanup_cmd(struct request *req)
 234 {
 235         if (req->rq_flags & RQF_SPECIAL_PAYLOAD)
 236                 kfree(bvec_virt(&req->special_vec));
 237 }
 238
 239 static blk_status_t virtblk_setup_cmd(struct virtio_device *vdev,
 240                                       struct request *req,
 241                                       struct virtblk_req *vbr)
 242 {
 243         size_t in_hdr_len = sizeof(vbr->in_hdr.status);
 244         bool unmap = false;
 245         u32 type;
 246         u64 sector = 0;
 247
 248         if (!IS_ENABLED(CONFIG_BLK_DEV_ZONED) && op_is_zone_mgmt(req_op(req)))
 249                 return BLK_STS_NOTSUPP;
 250
 251         /* Set fields for all request types */
 252         vbr->out_hdr.ioprio = cpu_to_virtio32(vdev, req_get_ioprio(req));
 253
 254         switch (req_op(req)) {
 255         case REQ_OP_READ:
 256                 type = VIRTIO_BLK_T_IN;
 257                 sector = blk_rq_pos(req);
 258                 break;
 259         case REQ_OP_WRITE:
 260                 type = VIRTIO_BLK_T_OUT;
 261                 sector = blk_rq_pos(req);
 262                 break;
 263         case REQ_OP_FLUSH:
 264                 type = VIRTIO_BLK_T_FLUSH;
 265                 break;
 266         case REQ_OP_DISCARD:
 267                 type = VIRTIO_BLK_T_DISCARD;
 268                 break;
 269         case REQ_OP_WRITE_ZEROES:
 270                 type = VIRTIO_BLK_T_WRITE_ZEROES;
 271                 unmap = !(req->cmd_flags & REQ_NOUNMAP);
 272                 break;
 273         case REQ_OP_SECURE_ERASE:
 274                 type = VIRTIO_BLK_T_SECURE_ERASE;
 275                 break;
 276         case REQ_OP_ZONE_OPEN:
 277                 type = VIRTIO_BLK_T_ZONE_OPEN;
 278                 sector = blk_rq_pos(req);
 279                 break;
 280         case REQ_OP_ZONE_CLOSE:
 281                 type = VIRTIO_BLK_T_ZONE_CLOSE;
 282                 sector = blk_rq_pos(req);
 283                 break;
 284         case REQ_OP_ZONE_FINISH:
 285                 type = VIRTIO_BLK_T_ZONE_FINISH;
 286                 sector = blk_rq_pos(req);
 287                 break;
 288         case REQ_OP_ZONE_APPEND:
 289                 type = VIRTIO_BLK_T_ZONE_APPEND;
 290                 sector = blk_rq_pos(req);
 291                 in_hdr_len = sizeof(vbr->in_hdr.zone_append);
 292                 break;
 293         case REQ_OP_ZONE_RESET:
 294                 type = VIRTIO_BLK_T_ZONE_RESET;
 295                 sector = blk_rq_pos(req);
 296                 break;
 297         case REQ_OP_ZONE_RESET_ALL:
 298                 type = VIRTIO_BLK_T_ZONE_RESET_ALL;
 299                 break;
 300         case REQ_OP_DRV_IN:
 301                 /*
 302                  * Out header has already been prepared by the caller (virtblk_get_id()
 303                  * or virtblk_submit_zone_report()), nothing to do here.
 304                  */
 305                 return 0;
 306         default:
 307                 WARN_ON_ONCE(1);
 308                 return BLK_STS_IOERR;
 309         }
 310
 311         /* Set fields for non-REQ_OP_DRV_IN request types */
 312         vbr->in_hdr_len = in_hdr_len;
 313         vbr->out_hdr.type = cpu_to_virtio32(vdev, type);
 314         vbr->out_hdr.sector = cpu_to_virtio64(vdev, sector);
 315
 316         if (type == VIRTIO_BLK_T_DISCARD || type == VIRTIO_BLK_T_WRITE_ZEROES ||
 317             type == VIRTIO_BLK_T_SECURE_ERASE) {
 318                 if (virtblk_setup_discard_write_zeroes_erase(req, unmap))
 319                         return BLK_STS_RESOURCE;
 320         }
 321
 322         return 0;
 323 }
 324
 325 /*
 326  * The status byte is always the last byte of the virtblk request
 327  * in-header. This helper fetches its value for all in-header formats
 328  * that are currently defined.
 329  */
 330 static inline u8 virtblk_vbr_status(struct virtblk_req *vbr)
 331 {
 332         return *((u8 *)&vbr->in_hdr + vbr->in_hdr_len - 1);
 333 }
 334
 335 static inline void virtblk_request_done(struct request *req)
 336 {
 337         struct virtblk_req *vbr = blk_mq_rq_to_pdu(req);
 338         blk_status_t status = virtblk_result(virtblk_vbr_status(vbr));
 339         struct virtio_blk *vblk = req->mq_hctx->queue->queuedata;
 340
 341         virtblk_unmap_data(req, vbr);
 342         virtblk_cleanup_cmd(req);
 343
 344         if (req_op(req) == REQ_OP_ZONE_APPEND)
 345                 req->__sector = virtio64_to_cpu(vblk->vdev,
 346                                                 vbr->in_hdr.zone_append.sector);
 347
 348         blk_mq_end_request(req, status);
 349 }
 350
 351 static void virtblk_done(struct virtqueue *vq)
 352 {
 353         struct virtio_blk *vblk = vq->vdev->priv;
 354         bool req_done = false;
 355         int qid = vq->index;
 356         struct virtblk_req *vbr;
 357         unsigned long flags;
 358         unsigned int len;
 359
 360         spin_lock_irqsave(&vblk->vqs[qid].lock, flags);
 361         do {
 362                 virtqueue_disable_cb(vq);
 363                 while ((vbr = virtqueue_get_buf(vblk->vqs[qid].vq, &len)) != NULL) {
 364                         struct request *req = blk_mq_rq_from_pdu(vbr);
 365
 366                         if (likely(!blk_should_fake_timeout(req->q)))
 367                                 blk_mq_complete_request(req);
 368                         req_done = true;
 369                 }
 370         } while (!virtqueue_enable_cb(vq));
 371
 372         /* In case queue is stopped waiting for more buffers. */
 373         if (req_done)
 374                 blk_mq_start_stopped_hw_queues(vblk->disk->queue, true);
 375         spin_unlock_irqrestore(&vblk->vqs[qid].lock, flags);
 376 }
 377
 378 static void virtio_commit_rqs(struct blk_mq_hw_ctx *hctx)
 379 {
 380         struct virtio_blk *vblk = hctx->queue->queuedata;
 381         struct virtio_blk_vq *vq = &vblk->vqs[hctx->queue_num];
 382         bool kick;
 383
 384         spin_lock_irq(&vq->lock);
 385         kick = virtqueue_kick_prepare(vq->vq);
 386         spin_unlock_irq(&vq->lock);
 387
 388         if (kick)
 389                 virtqueue_notify(vq->vq);
 390 }
 391
 392 static blk_status_t virtblk_fail_to_queue(struct request *req, int rc)
 393 {
 394         virtblk_cleanup_cmd(req);
 395         switch (rc) {
 396         case -ENOSPC:
 397                 return BLK_STS_DEV_RESOURCE;
 398         case -ENOMEM:
 399                 return BLK_STS_RESOURCE;
 400         default:
 401                 return BLK_STS_IOERR;
 402         }
 403 }
 404
 405 static blk_status_t virtblk_prep_rq(struct blk_mq_hw_ctx *hctx,
 406                                         struct virtio_blk *vblk,
 407                                         struct request *req,
 408                                         struct virtblk_req *vbr)
 409 {
 410         blk_status_t status;
 411         int num;
 412
 413         status = virtblk_setup_cmd(vblk->vdev, req, vbr);
 414         if (unlikely(status))
 415                 return status;
 416
 417         num = virtblk_map_data(hctx, req, vbr);
 418         if (unlikely(num < 0))
 419                 return virtblk_fail_to_queue(req, -ENOMEM);
 420         vbr->sg_table.nents = num;
 421
 422         blk_mq_start_request(req);
 423
 424         return BLK_STS_OK;
 425 }
 426
 427 static blk_status_t virtio_queue_rq(struct blk_mq_hw_ctx *hctx,
 428                            const struct blk_mq_queue_data *bd)
 429 {
 430         struct virtio_blk *vblk = hctx->queue->queuedata;
 431         struct request *req = bd->rq;
 432         struct virtblk_req *vbr = blk_mq_rq_to_pdu(req);
 433         unsigned long flags;
 434         int qid = hctx->queue_num;
 435         bool notify = false;
 436         blk_status_t status;
 437         int err;
 438
 439         status = virtblk_prep_rq(hctx, vblk, req, vbr);
 440         if (unlikely(status))
 441                 return status;
 442
 443         spin_lock_irqsave(&vblk->vqs[qid].lock, flags);
 444         err = virtblk_add_req(vblk->vqs[qid].vq, vbr);
 445         if (err) {
 446                 virtqueue_kick(vblk->vqs[qid].vq);
 447                 /* Don't stop the queue if -ENOMEM: we may have failed to
 448                  * bounce the buffer due to global resource outage.
 449                  */
 450                 if (err == -ENOSPC)
 451                         blk_mq_stop_hw_queue(hctx);
 452                 spin_unlock_irqrestore(&vblk->vqs[qid].lock, flags);
 453                 virtblk_unmap_data(req, vbr);
 454                 return virtblk_fail_to_queue(req, err);
 455         }
 456
 457         if (bd->last && virtqueue_kick_prepare(vblk->vqs[qid].vq))
 458                 notify = true;
 459         spin_unlock_irqrestore(&vblk->vqs[qid].lock, flags);
 460
 461         if (notify)
 462                 virtqueue_notify(vblk->vqs[qid].vq);
 463         return BLK_STS_OK;
 464 }
 465
 466 static bool virtblk_prep_rq_batch(struct request *req)
 467 {
 468         struct virtio_blk *vblk = req->mq_hctx->queue->queuedata;
 469         struct virtblk_req *vbr = blk_mq_rq_to_pdu(req);
 470
 471         return virtblk_prep_rq(req->mq_hctx, vblk, req, vbr) == BLK_STS_OK;
 472 }
 473
 474 static bool virtblk_add_req_batch(struct virtio_blk_vq *vq,
 475                                         struct request **rqlist)
 476 {
 477         unsigned long flags;
 478         int err;
 479         bool kick;
 480
 481         spin_lock_irqsave(&vq->lock, flags);
 482
 483         while (!rq_list_empty(*rqlist)) {
 484                 struct request *req = rq_list_pop(rqlist);
 485                 struct virtblk_req *vbr = blk_mq_rq_to_pdu(req);
 486
 487                 err = virtblk_add_req(vq->vq, vbr);
 488                 if (err) {
 489                         virtblk_unmap_data(req, vbr);
 490                         virtblk_cleanup_cmd(req);
 491                         blk_mq_requeue_request(req, true);
 492                 }
 493         }
 494
 495         kick = virtqueue_kick_prepare(vq->vq);
 496         spin_unlock_irqrestore(&vq->lock, flags);
 497
 498         return kick;
 499 }
 500
 501 static void virtio_queue_rqs(struct request **rqlist)
 502 {
 503         struct request *req, *next, *prev = NULL;
 504         struct request *requeue_list = NULL;
 505
 506         rq_list_for_each_safe(rqlist, req, next) {
 507                 struct virtio_blk_vq *vq = get_virtio_blk_vq(req->mq_hctx);
 508                 bool kick;
 509
 510                 if (!virtblk_prep_rq_batch(req)) {
 511                         rq_list_move(rqlist, &requeue_list, req, prev);
 512                         req = prev;
 513                         if (!req)
 514                                 continue;
 515                 }
 516
 517                 if (!next || req->mq_hctx != next->mq_hctx) {
 518                         req->rq_next = NULL;
 519                         kick = virtblk_add_req_batch(vq, rqlist);
 520                         if (kick)
 521                                 virtqueue_notify(vq->vq);
 522
 523                         *rqlist = next;
 524                         prev = NULL;
 525                 } else
 526                         prev = req;
 527         }
 528
 529         *rqlist = requeue_list;
 530 }
 531
 532 #ifdef CONFIG_BLK_DEV_ZONED
 533 static void *virtblk_alloc_report_buffer(struct virtio_blk *vblk,
 534                                           unsigned int nr_zones,
 535                                           size_t *buflen)
 536 {
 537         struct request_queue *q = vblk->disk->queue;
 538         size_t bufsize;
 539         void *buf;
 540
 541         nr_zones = min_t(unsigned int, nr_zones,
 542                          get_capacity(vblk->disk) >> ilog2(vblk->zone_sectors));
 543
 544         bufsize = sizeof(struct virtio_blk_zone_report) +
 545                 nr_zones * sizeof(struct virtio_blk_zone_descriptor);
 546         bufsize = min_t(size_t, bufsize,
 547                         queue_max_hw_sectors(q) << SECTOR_SHIFT);
 548         bufsize = min_t(size_t, bufsize, queue_max_segments(q) << PAGE_SHIFT);
 549
 550         while (bufsize >= sizeof(struct virtio_blk_zone_report)) {
 551                 buf = __vmalloc(bufsize, GFP_KERNEL | __GFP_NORETRY);
 552                 if (buf) {
 553                         *buflen = bufsize;
 554                         return buf;
 555                 }
 556                 bufsize >>= 1;
 557         }
 558
 559         return NULL;
 560 }
 561
 562 static int virtblk_submit_zone_report(struct virtio_blk *vblk,
 563                                        char *report_buf, size_t report_len,
 564                                        sector_t sector)
 565 {
 566         struct request_queue *q = vblk->disk->queue;
 567         struct request *req;
 568         struct virtblk_req *vbr;
 569         int err;
 570
 571         req = blk_mq_alloc_request(q, REQ_OP_DRV_IN, 0);
 572         if (IS_ERR(req))
 573                 return PTR_ERR(req);
 574
 575         vbr = blk_mq_rq_to_pdu(req);
 576         vbr->in_hdr_len = sizeof(vbr->in_hdr.status);
 577         vbr->out_hdr.type = cpu_to_virtio32(vblk->vdev, VIRTIO_BLK_T_ZONE_REPORT);
 578         vbr->out_hdr.sector = cpu_to_virtio64(vblk->vdev, sector);
 579
 580         err = blk_rq_map_kern(q, req, report_buf, report_len, GFP_KERNEL);
 581         if (err)
 582                 goto out;
 583
 584         blk_execute_rq(req, false);
 585         err = blk_status_to_errno(virtblk_result(vbr->in_hdr.status));
 586 out:
 587         blk_mq_free_request(req);
 588         return err;
 589 }
 590
 591 static int virtblk_parse_zone(struct virtio_blk *vblk,
 592                                struct virtio_blk_zone_descriptor *entry,
 593                                unsigned int idx, report_zones_cb cb, void *data)
 594 {
 595         struct blk_zone zone = { };
 596
 597         zone.start = virtio64_to_cpu(vblk->vdev, entry->z_start);
 598         if (zone.start + vblk->zone_sectors <= get_capacity(vblk->disk))
 599                 zone.len = vblk->zone_sectors;
 600         else
 601                 zone.len = get_capacity(vblk->disk) - zone.start;
 602         zone.capacity = virtio64_to_cpu(vblk->vdev, entry->z_cap);
 603         zone.wp = virtio64_to_cpu(vblk->vdev, entry->z_wp);
 604
 605         switch (entry->z_type) {
 606         case VIRTIO_BLK_ZT_SWR:
 607                 zone.type = BLK_ZONE_TYPE_SEQWRITE_REQ;
 608                 break;
 609         case VIRTIO_BLK_ZT_SWP:
 610                 zone.type = BLK_ZONE_TYPE_SEQWRITE_PREF;
 611                 break;
 612         case VIRTIO_BLK_ZT_CONV:
 613                 zone.type = BLK_ZONE_TYPE_CONVENTIONAL;
 614                 break;
 615         default:
 616                 dev_err(&vblk->vdev->dev, "zone %llu: invalid type %#x\n",
 617                         zone.start, entry->z_type);
 618                 return -EIO;
 619         }
 620
 621         switch (entry->z_state) {
 622         case VIRTIO_BLK_ZS_EMPTY:
 623                 zone.cond = BLK_ZONE_COND_EMPTY;
 624                 break;
 625         case VIRTIO_BLK_ZS_CLOSED:
 626                 zone.cond = BLK_ZONE_COND_CLOSED;
 627                 break;
 628         case VIRTIO_BLK_ZS_FULL:
 629                 zone.cond = BLK_ZONE_COND_FULL;
 630                 zone.wp = zone.start + zone.len;
 631                 break;
 632         case VIRTIO_BLK_ZS_EOPEN:
 633                 zone.cond = BLK_ZONE_COND_EXP_OPEN;
 634                 break;
 635         case VIRTIO_BLK_ZS_IOPEN:
 636                 zone.cond = BLK_ZONE_COND_IMP_OPEN;
 637                 break;
 638         case VIRTIO_BLK_ZS_NOT_WP:
 639                 zone.cond = BLK_ZONE_COND_NOT_WP;
 640                 break;
 641         case VIRTIO_BLK_ZS_RDONLY:
 642                 zone.cond = BLK_ZONE_COND_READONLY;
 643                 zone.wp = ULONG_MAX;
 644                 break;
 645         case VIRTIO_BLK_ZS_OFFLINE:
 646                 zone.cond = BLK_ZONE_COND_OFFLINE;
 647                 zone.wp = ULONG_MAX;
 648                 break;
 649         default:
 650                 dev_err(&vblk->vdev->dev, "zone %llu: invalid condition %#x\n",
 651                         zone.start, entry->z_state);
 652                 return -EIO;
 653         }
 654
 655         /*
 656          * The callback below checks the validity of the reported
 657          * entry data, no need to further validate it here.
 658          */
 659         return cb(&zone, idx, data);
 660 }
 661
 662 static int virtblk_report_zones(struct gendisk *disk, sector_t sector,
 663                                  unsigned int nr_zones, report_zones_cb cb,
 664                                  void *data)
 665 {
 666         struct virtio_blk *vblk = disk->private_data;
 667         struct virtio_blk_zone_report *report;
 668         unsigned long long nz, i;
 669         size_t buflen;
 670         unsigned int zone_idx = 0;
 671         int ret;
 672
 673         if (WARN_ON_ONCE(!vblk->zone_sectors))
 674                 return -EOPNOTSUPP;
 675
 676         report = virtblk_alloc_report_buffer(vblk, nr_zones, &buflen);
 677         if (!report)
 678                 return -ENOMEM;
 679
 680         mutex_lock(&vblk->vdev_mutex);
 681
 682         if (!vblk->vdev) {
 683                 ret = -ENXIO;
 684                 goto fail_report;
 685         }
 686
 687         while (zone_idx < nr_zones && sector < get_capacity(vblk->disk)) {
 688                 memset(report, 0, buflen);
 689
 690                 ret = virtblk_submit_zone_report(vblk, (char *)report,
 691                                                  buflen, sector);
 692                 if (ret)
 693                         goto fail_report;
 694
 695                 nz = min_t(u64, virtio64_to_cpu(vblk->vdev, report->nr_zones),
 696                            nr_zones);
 697                 if (!nz)
 698                         break;
 699
 700                 for (i = 0; i < nz && zone_idx < nr_zones; i++) {
 701                         ret = virtblk_parse_zone(vblk, &report->zones[i],
 702                                                  zone_idx, cb, data);
 703                         if (ret)
 704                                 goto fail_report;
 705
 706                         sector = virtio64_to_cpu(vblk->vdev,
 707                                                  report->zones[i].z_start) +
 708                                  vblk->zone_sectors;
 709                         zone_idx++;
 710                 }
 711         }
 712
 713         if (zone_idx > 0)
 714                 ret = zone_idx;
 715         else
 716                 ret = -EINVAL;
 717 fail_report:
 718         mutex_unlock(&vblk->vdev_mutex);
 719         kvfree(report);
 720         return ret;
 721 }
 722
 723 static int virtblk_read_zoned_limits(struct virtio_blk *vblk,
 724                 struct queue_limits *lim)
 725 {
 726         struct virtio_device *vdev = vblk->vdev;
 727         u32 v, wg;
 728
 729         dev_dbg(&vdev->dev, "probing host-managed zoned device\n");
 730
 731         lim->zoned = true;
 732
 733         virtio_cread(vdev, struct virtio_blk_config,
 734                      zoned.max_open_zones, &v);
 735         lim->max_open_zones = v;
 736         dev_dbg(&vdev->dev, "max open zones = %u\n", v);
 737
 738         virtio_cread(vdev, struct virtio_blk_config,
 739                      zoned.max_active_zones, &v);
 740         lim->max_active_zones = v;
 741         dev_dbg(&vdev->dev, "max active zones = %u\n", v);
 742
 743         virtio_cread(vdev, struct virtio_blk_config,
 744                      zoned.write_granularity, &wg);
 745         if (!wg) {
 746                 dev_warn(&vdev->dev, "zero write granularity reported\n");
 747                 return -ENODEV;
 748         }
 749         lim->physical_block_size = wg;
 750         lim->io_min = wg;
 751
 752         dev_dbg(&vdev->dev, "write granularity = %u\n", wg);
 753
 754         /*
 755          * virtio ZBD specification doesn't require zones to be a power of
 756          * two sectors in size, but the code in this driver expects that.
 757          */
 758         virtio_cread(vdev, struct virtio_blk_config, zoned.zone_sectors,
 759                      &vblk->zone_sectors);
 760         if (vblk->zone_sectors == 0 || !is_power_of_2(vblk->zone_sectors)) {
 761                 dev_err(&vdev->dev,
 762                         "zoned device with non power of two zone size %u\n",
 763                         vblk->zone_sectors);
 764                 return -ENODEV;
 765         }
 766         lim->chunk_sectors = vblk->zone_sectors;
 767         dev_dbg(&vdev->dev, "zone sectors = %u\n", vblk->zone_sectors);
 768
 769         if (virtio_has_feature(vdev, VIRTIO_BLK_F_DISCARD)) {
 770                 dev_warn(&vblk->vdev->dev,
 771                          "ignoring negotiated F_DISCARD for zoned device\n");
 772                 lim->max_hw_discard_sectors = 0;
 773         }
 774
 775         virtio_cread(vdev, struct virtio_blk_config,
 776                      zoned.max_append_sectors, &v);
 777         if (!v) {
 778                 dev_warn(&vdev->dev, "zero max_append_sectors reported\n");
 779                 return -ENODEV;
 780         }
 781         if ((v << SECTOR_SHIFT) < wg) {
 782                 dev_err(&vdev->dev,
 783                         "write granularity %u exceeds max_append_sectors %u limit\n",
 784                         wg, v);
 785                 return -ENODEV;
 786         }
 787         lim->max_zone_append_sectors = v;
 788         dev_dbg(&vdev->dev, "max append sectors = %u\n", v);
 789
 790         return 0;
 791 }
 792 #else
 793 /*
 794  * Zoned block device support is not configured in this kernel, host-managed
 795  * zoned devices can't be supported.
 796  */
 797 #define virtblk_report_zones       NULL
 798 static inline int virtblk_read_zoned_limits(struct virtio_blk *vblk,
 799                 struct queue_limits *lim)
 800 {
 801         dev_err(&vblk->vdev->dev,
 802                 "virtio_blk: zoned devices are not supported");
 803         return -EOPNOTSUPP;
 804 }
 805 #endif /* CONFIG_BLK_DEV_ZONED */
 806
 807 /* return id (s/n) string for *disk to *id_str
 808  */
 809 static int virtblk_get_id(struct gendisk *disk, char *id_str)
 810 {
 811         struct virtio_blk *vblk = disk->private_data;
 812         struct request_queue *q = vblk->disk->queue;
 813         struct request *req;
 814         struct virtblk_req *vbr;
 815         int err;
 816
 817         req = blk_mq_alloc_request(q, REQ_OP_DRV_IN, 0);
 818         if (IS_ERR(req))
 819                 return PTR_ERR(req);
 820
 821         vbr = blk_mq_rq_to_pdu(req);
 822         vbr->in_hdr_len = sizeof(vbr->in_hdr.status);
 823         vbr->out_hdr.type = cpu_to_virtio32(vblk->vdev, VIRTIO_BLK_T_GET_ID);
 824         vbr->out_hdr.sector = 0;
 825
 826         err = blk_rq_map_kern(q, req, id_str, VIRTIO_BLK_ID_BYTES, GFP_KERNEL);
 827         if (err)
 828                 goto out;
 829
 830         blk_execute_rq(req, false);
 831         err = blk_status_to_errno(virtblk_result(vbr->in_hdr.status));
 832 out:
 833         blk_mq_free_request(req);
 834         return err;
 835 }
 836
 837 /* We provide getgeo only to please some old bootloader/partitioning tools */
 838 static int virtblk_getgeo(struct block_device *bd, struct hd_geometry *geo)
 839 {
 840         struct virtio_blk *vblk = bd->bd_disk->private_data;
 841         int ret = 0;
 842
 843         mutex_lock(&vblk->vdev_mutex);
 844
 845         if (!vblk->vdev) {
 846                 ret = -ENXIO;
 847                 goto out;
 848         }
 849
 850         /* see if the host passed in geometry config */
 851         if (virtio_has_feature(vblk->vdev, VIRTIO_BLK_F_GEOMETRY)) {
 852                 virtio_cread(vblk->vdev, struct virtio_blk_config,
 853                              geometry.cylinders, &geo->cylinders);
 854                 virtio_cread(vblk->vdev, struct virtio_blk_config,
 855                              geometry.heads, &geo->heads);
 856                 virtio_cread(vblk->vdev, struct virtio_blk_config,
 857                              geometry.sectors, &geo->sectors);
 858         } else {
 859                 /* some standard values, similar to sd */
 860                 geo->heads = 1 << 6;
 861                 geo->sectors = 1 << 5;
 862                 geo->cylinders = get_capacity(bd->bd_disk) >> 11;
 863         }
 864 out:
 865         mutex_unlock(&vblk->vdev_mutex);
 866         return ret;
 867 }
 868
 869 static void virtblk_free_disk(struct gendisk *disk)
 870 {
 871         struct virtio_blk *vblk = disk->private_data;
 872
 873         ida_free(&vd_index_ida, vblk->index);
 874         mutex_destroy(&vblk->vdev_mutex);
 875         kfree(vblk);
 876 }
 877
 878 static const struct block_device_operations virtblk_fops = {
 879         .owner          = THIS_MODULE,
 880         .getgeo         = virtblk_getgeo,
 881         .free_disk      = virtblk_free_disk,
 882         .report_zones   = virtblk_report_zones,
 883 };
 884
 885 static int index_to_minor(int index)
 886 {
 887         return index << PART_BITS;
 888 }
 889
 890 static int minor_to_index(int minor)
 891 {
 892         return minor >> PART_BITS;
 893 }
 894
 895 static ssize_t serial_show(struct device *dev,
 896                            struct device_attribute *attr, char *buf)
 897 {
 898         struct gendisk *disk = dev_to_disk(dev);
 899         int err;
 900
 901         /* sysfs gives us a PAGE_SIZE buffer */
 902         BUILD_BUG_ON(PAGE_SIZE < VIRTIO_BLK_ID_BYTES);
 903
 904         buf[VIRTIO_BLK_ID_BYTES] = '\0';
 905         err = virtblk_get_id(disk, buf);
 906         if (!err)
 907                 return strlen(buf);
 908
 909         if (err == -EIO) /* Unsupported? Make it empty. */
 910                 return 0;
 911
 912         return err;
 913 }
 914
 915 static DEVICE_ATTR_RO(serial);
 916
 917 /* The queue's logical block size must be set before calling this */
 918 static void virtblk_update_capacity(struct virtio_blk *vblk, bool resize)
 919 {
 920         struct virtio_device *vdev = vblk->vdev;
 921         struct request_queue *q = vblk->disk->queue;
 922         char cap_str_2[10], cap_str_10[10];
 923         unsigned long long nblocks;
 924         u64 capacity;
 925
 926         /* Host must always specify the capacity. */
 927         virtio_cread(vdev, struct virtio_blk_config, capacity, &capacity);
 928
 929         nblocks = DIV_ROUND_UP_ULL(capacity, queue_logical_block_size(q) >> 9);
 930
 931         string_get_size(nblocks, queue_logical_block_size(q),
 932                         STRING_UNITS_2, cap_str_2, sizeof(cap_str_2));
 933         string_get_size(nblocks, queue_logical_block_size(q),
 934                         STRING_UNITS_10, cap_str_10, sizeof(cap_str_10));
 935
 936         dev_notice(&vdev->dev,
 937                    "[%s] %s%llu %d-byte logical blocks (%s/%s)\n",
 938                    vblk->disk->disk_name,
 939                    resize ? "new size: " : "",
 940                    nblocks,
 941                    queue_logical_block_size(q),
 942                    cap_str_10,
 943                    cap_str_2);
 944
 945         set_capacity_and_notify(vblk->disk, capacity);
 946 }
 947
 948 static void virtblk_config_changed_work(struct work_struct *work)
 949 {
 950         struct virtio_blk *vblk =
 951                 container_of(work, struct virtio_blk, config_work);
 952
 953         virtblk_update_capacity(vblk, true);
 954 }
 955
 956 static void virtblk_config_changed(struct virtio_device *vdev)
 957 {
 958         struct virtio_blk *vblk = vdev->priv;
 959
 960         queue_work(virtblk_wq, &vblk->config_work);
 961 }
 962
 963 static int init_vq(struct virtio_blk *vblk)
 964 {
 965         int err;
 966         unsigned short i;
 967         vq_callback_t **callbacks;
 968         const char **names;
 969         struct virtqueue **vqs;
 970         unsigned short num_vqs;
 971         unsigned short num_poll_vqs;
 972         struct virtio_device *vdev = vblk->vdev;
 973         struct irq_affinity desc = { 0, };
 974
 975         err = virtio_cread_feature(vdev, VIRTIO_BLK_F_MQ,
 976                                    struct virtio_blk_config, num_queues,
 977                                    &num_vqs);
 978         if (err)
 979                 num_vqs = 1;
 980
 981         if (!err && !num_vqs) {
 982                 dev_err(&vdev->dev, "MQ advertised but zero queues reported\n");
 983                 return -EINVAL;
 984         }
 985
 986         num_vqs = min_t(unsigned int,
 987                         min_not_zero(num_request_queues, nr_cpu_ids),
 988                         num_vqs);
 989
 990         num_poll_vqs = min_t(unsigned int, poll_queues, num_vqs - 1);
 991
 992         vblk->io_queues[HCTX_TYPE_DEFAULT] = num_vqs - num_poll_vqs;
 993         vblk->io_queues[HCTX_TYPE_READ] = 0;
 994         vblk->io_queues[HCTX_TYPE_POLL] = num_poll_vqs;
 995
 996         dev_info(&vdev->dev, "%d/%d/%d default/read/poll queues\n",
 997                                 vblk->io_queues[HCTX_TYPE_DEFAULT],
 998                                 vblk->io_queues[HCTX_TYPE_READ],
 999                                 vblk->io_queues[HCTX_TYPE_POLL]);
1000
1001         vblk->vqs = kmalloc_array(num_vqs, sizeof(*vblk->vqs), GFP_KERNEL);
1002         if (!vblk->vqs)
1003                 return -ENOMEM;
1004
1005         names = kmalloc_array(num_vqs, sizeof(*names), GFP_KERNEL);
1006         callbacks = kmalloc_array(num_vqs, sizeof(*callbacks), GFP_KERNEL);
1007         vqs = kmalloc_array(num_vqs, sizeof(*vqs), GFP_KERNEL);
1008         if (!names || !callbacks || !vqs) {
1009                 err = -ENOMEM;
1010                 goto out;
1011         }
1012
1013         for (i = 0; i < num_vqs - num_poll_vqs; i++) {
1014                 callbacks[i] = virtblk_done;
1015                 snprintf(vblk->vqs[i].name, VQ_NAME_LEN, "req.%u", i);
1016                 names[i] = vblk->vqs[i].name;
1017         }
1018
1019         for (; i < num_vqs; i++) {
1020                 callbacks[i] = NULL;
1021                 snprintf(vblk->vqs[i].name, VQ_NAME_LEN, "req_poll.%u", i);
1022                 names[i] = vblk->vqs[i].name;
1023         }
1024
1025         /* Discover virtqueues and write information to configuration.  */
1026         err = virtio_find_vqs(vdev, num_vqs, vqs, callbacks, names, &desc);
1027         if (err)
1028                 goto out;
1029
1030         for (i = 0; i < num_vqs; i++) {
1031                 spin_lock_init(&vblk->vqs[i].lock);
1032                 vblk->vqs[i].vq = vqs[i];
1033         }
1034         vblk->num_vqs = num_vqs;
1035
1036 out:
1037         kfree(vqs);
1038         kfree(callbacks);
1039         kfree(names);
1040         if (err)
1041                 kfree(vblk->vqs);
1042         return err;
1043 }
1044
1045 /*
1046  * Legacy naming scheme used for virtio devices.  We are stuck with it for
1047  * virtio blk but don't ever use it for any new driver.
1048  */
1049 static int virtblk_name_format(char *prefix, int index, char *buf, int buflen)
1050 {
1051         const int base = 'z' - 'a' + 1;
1052         char *begin = buf + strlen(prefix);
1053         char *end = buf + buflen;
1054         char *p;
1055         int unit;
1056
1057         p = end - 1;
1058         *p = '\0';
1059         unit = base;
1060         do {
1061                 if (p == begin)
1062                         return -EINVAL;
1063                 *--p = 'a' + (index % unit);
1064                 index = (index / unit) - 1;
1065         } while (index >= 0);
1066
1067         memmove(begin, p, end - p);
1068         memcpy(buf, prefix, strlen(prefix));
1069
1070         return 0;
1071 }
1072
1073 static int virtblk_get_cache_mode(struct virtio_device *vdev)
1074 {
1075         u8 writeback;
1076         int err;
1077
1078         err = virtio_cread_feature(vdev, VIRTIO_BLK_F_CONFIG_WCE,
1079                                    struct virtio_blk_config, wce,
1080                                    &writeback);
1081
1082         /*
1083          * If WCE is not configurable and flush is not available,
1084          * assume no writeback cache is in use.
1085          */
1086         if (err)
1087                 writeback = virtio_has_feature(vdev, VIRTIO_BLK_F_FLUSH);
1088
1089         return writeback;
1090 }
1091
1092 static void virtblk_update_cache_mode(struct virtio_device *vdev)
1093 {
1094         u8 writeback = virtblk_get_cache_mode(vdev);
1095         struct virtio_blk *vblk = vdev->priv;
1096
1097         blk_queue_write_cache(vblk->disk->queue, writeback, false);
1098 }
1099
1100 static const char *const virtblk_cache_types[] = {
1101         "write through", "write back"
1102 };
1103
1104 static ssize_t
1105 cache_type_store(struct device *dev, struct device_attribute *attr,
1106                  const char *buf, size_t count)
1107 {
1108         struct gendisk *disk = dev_to_disk(dev);
1109         struct virtio_blk *vblk = disk->private_data;
1110         struct virtio_device *vdev = vblk->vdev;
1111         int i;
1112
1113         BUG_ON(!virtio_has_feature(vblk->vdev, VIRTIO_BLK_F_CONFIG_WCE));
1114         i = sysfs_match_string(virtblk_cache_types, buf);
1115         if (i < 0)
1116                 return i;
1117
1118         virtio_cwrite8(vdev, offsetof(struct virtio_blk_config, wce), i);
1119         virtblk_update_cache_mode(vdev);
1120         return count;
1121 }
1122
1123 static ssize_t
1124 cache_type_show(struct device *dev, struct device_attribute *attr, char *buf)
1125 {
1126         struct gendisk *disk = dev_to_disk(dev);
1127         struct virtio_blk *vblk = disk->private_data;
1128         u8 writeback = virtblk_get_cache_mode(vblk->vdev);
1129
1130         BUG_ON(writeback >= ARRAY_SIZE(virtblk_cache_types));
1131         return sysfs_emit(buf, "%s\n", virtblk_cache_types[writeback]);
1132 }
1133
1134 static DEVICE_ATTR_RW(cache_type);
1135
1136 static struct attribute *virtblk_attrs[] = {
1137         &dev_attr_serial.attr,
1138         &dev_attr_cache_type.attr,
1139         NULL,
1140 };
1141
1142 static umode_t virtblk_attrs_are_visible(struct kobject *kobj,
1143                 struct attribute *a, int n)
1144 {
1145         struct device *dev = kobj_to_dev(kobj);
1146         struct gendisk *disk = dev_to_disk(dev);
1147         struct virtio_blk *vblk = disk->private_data;
1148         struct virtio_device *vdev = vblk->vdev;
1149
1150         if (a == &dev_attr_cache_type.attr &&
1151             !virtio_has_feature(vdev, VIRTIO_BLK_F_CONFIG_WCE))
1152                 return S_IRUGO;
1153
1154         return a->mode;
1155 }
1156
1157 static const struct attribute_group virtblk_attr_group = {
1158         .attrs = virtblk_attrs,
1159         .is_visible = virtblk_attrs_are_visible,
1160 };
1161
1162 static const struct attribute_group *virtblk_attr_groups[] = {
1163         &virtblk_attr_group,
1164         NULL,
1165 };
1166
1167 static void virtblk_map_queues(struct blk_mq_tag_set *set)
1168 {
1169         struct virtio_blk *vblk = set->driver_data;
1170         int i, qoff;
1171
1172         for (i = 0, qoff = 0; i < set->nr_maps; i++) {
1173                 struct blk_mq_queue_map *map = &set->map[i];
1174
1175                 map->nr_queues = vblk->io_queues[i];
1176                 map->queue_offset = qoff;
1177                 qoff += map->nr_queues;
1178
1179                 if (map->nr_queues == 0)
1180                         continue;
1181
1182                 /*
1183                  * Regular queues have interrupts and hence CPU affinity is
1184                  * defined by the core virtio code, but polling queues have
1185                  * no interrupts so we let the block layer assign CPU affinity.
1186                  */
1187                 if (i == HCTX_TYPE_POLL)
1188                         blk_mq_map_queues(&set->map[i]);
1189                 else
1190                         blk_mq_virtio_map_queues(&set->map[i], vblk->vdev, 0);
1191         }
1192 }
1193
1194 static void virtblk_complete_batch(struct io_comp_batch *iob)
1195 {
1196         struct request *req;
1197
1198         rq_list_for_each(&iob->req_list, req) {
1199                 virtblk_unmap_data(req, blk_mq_rq_to_pdu(req));
1200                 virtblk_cleanup_cmd(req);
1201         }
1202         blk_mq_end_request_batch(iob);
1203 }
1204
1205 static int virtblk_poll(struct blk_mq_hw_ctx *hctx, struct io_comp_batch *iob)
1206 {
1207         struct virtio_blk *vblk = hctx->queue->queuedata;
1208         struct virtio_blk_vq *vq = get_virtio_blk_vq(hctx);
1209         struct virtblk_req *vbr;
1210         unsigned long flags;
1211         unsigned int len;
1212         int found = 0;
1213
1214         spin_lock_irqsave(&vq->lock, flags);
1215
1216         while ((vbr = virtqueue_get_buf(vq->vq, &len)) != NULL) {
1217                 struct request *req = blk_mq_rq_from_pdu(vbr);
1218
1219                 found++;
1220                 if (!blk_mq_complete_request_remote(req) &&
1221                     !blk_mq_add_to_batch(req, iob, virtblk_vbr_status(vbr),
1222                                                 virtblk_complete_batch))
1223                         virtblk_request_done(req);
1224         }
1225
1226         if (found)
1227                 blk_mq_start_stopped_hw_queues(vblk->disk->queue, true);
1228
1229         spin_unlock_irqrestore(&vq->lock, flags);
1230
1231         return found;
1232 }
1233
1234 static const struct blk_mq_ops virtio_mq_ops = {
1235         .queue_rq       = virtio_queue_rq,
1236         .queue_rqs      = virtio_queue_rqs,
1237         .commit_rqs     = virtio_commit_rqs,
1238         .complete       = virtblk_request_done,
1239         .map_queues     = virtblk_map_queues,
1240         .poll           = virtblk_poll,
1241 };
1242
1243 static unsigned int virtblk_queue_depth;
1244 module_param_named(queue_depth, virtblk_queue_depth, uint, 0444);
1245
1246 static int virtblk_read_limits(struct virtio_blk *vblk,
1247                 struct queue_limits *lim)
1248 {
1249         struct virtio_device *vdev = vblk->vdev;
1250         u32 v, blk_size, max_size, sg_elems, opt_io_size;
1251         u32 max_discard_segs = 0;
1252         u32 discard_granularity = 0;
1253         u16 min_io_size;
1254         u8 physical_block_exp, alignment_offset;
1255         size_t max_dma_size;
1256         int err;
1257
1258         /* We need to know how many segments before we allocate. */
1259         err = virtio_cread_feature(vdev, VIRTIO_BLK_F_SEG_MAX,
1260                                    struct virtio_blk_config, seg_max,
1261                                    &sg_elems);
1262
1263         /* We need at least one SG element, whatever they say. */
1264         if (err || !sg_elems)
1265                 sg_elems = 1;
1266
1267         /* Prevent integer overflows and honor max vq size */
1268         sg_elems = min_t(u32, sg_elems, VIRTIO_BLK_MAX_SG_ELEMS - 2);
1269
1270         /* We can handle whatever the host told us to handle. */
1271         lim->max_segments = sg_elems;
1272
1273         /* No real sector limit. */
1274         lim->max_hw_sectors = UINT_MAX;
1275
1276         max_dma_size = virtio_max_dma_size(vdev);
1277         max_size = max_dma_size > U32_MAX ? U32_MAX : max_dma_size;
1278
1279         /* Host can optionally specify maximum segment size and number of
1280          * segments. */
1281         err = virtio_cread_feature(vdev, VIRTIO_BLK_F_SIZE_MAX,
1282                                    struct virtio_blk_config, size_max, &v);
1283         if (!err)
1284                 max_size = min(max_size, v);
1285
1286         lim->max_segment_size = max_size;
1287
1288         /* Host can optionally specify the block size of the device */
1289         err = virtio_cread_feature(vdev, VIRTIO_BLK_F_BLK_SIZE,
1290                                    struct virtio_blk_config, blk_size,
1291                                    &blk_size);
1292         if (!err) {
1293                 err = blk_validate_block_size(blk_size);
1294                 if (err) {
1295                         dev_err(&vdev->dev,
1296                                 "virtio_blk: invalid block size: 0x%x\n",
1297                                 blk_size);
1298                         return err;
1299                 }
1300
1301                 lim->logical_block_size = blk_size;
1302         } else
1303                 blk_size = lim->logical_block_size;
1304
1305         /* Use topology information if available */
1306         err = virtio_cread_feature(vdev, VIRTIO_BLK_F_TOPOLOGY,
1307                                    struct virtio_blk_config, physical_block_exp,
1308                                    &physical_block_exp);
1309         if (!err && physical_block_exp)
1310                 lim->physical_block_size = blk_size * (1 << physical_block_exp);
1311
1312         err = virtio_cread_feature(vdev, VIRTIO_BLK_F_TOPOLOGY,
1313                                    struct virtio_blk_config, alignment_offset,
1314                                    &alignment_offset);
1315         if (!err && alignment_offset)
1316                 lim->alignment_offset = blk_size * alignment_offset;
1317
1318         err = virtio_cread_feature(vdev, VIRTIO_BLK_F_TOPOLOGY,
1319                                    struct virtio_blk_config, min_io_size,
1320                                    &min_io_size);
1321         if (!err && min_io_size)
1322                 lim->io_min = blk_size * min_io_size;
1323
1324         err = virtio_cread_feature(vdev, VIRTIO_BLK_F_TOPOLOGY,
1325                                    struct virtio_blk_config, opt_io_size,
1326                                    &opt_io_size);
1327         if (!err && opt_io_size)
1328                 lim->io_opt = blk_size * opt_io_size;
1329
1330         if (virtio_has_feature(vdev, VIRTIO_BLK_F_DISCARD)) {
1331                 virtio_cread(vdev, struct virtio_blk_config,
1332                              discard_sector_alignment, &discard_granularity);
1333
1334                 virtio_cread(vdev, struct virtio_blk_config,
1335                              max_discard_sectors, &v);
1336                 lim->max_hw_discard_sectors = v ? v : UINT_MAX;
1337
1338                 virtio_cread(vdev, struct virtio_blk_config, max_discard_seg,
1339                              &max_discard_segs);
1340         }
1341
1342         if (virtio_has_feature(vdev, VIRTIO_BLK_F_WRITE_ZEROES)) {
1343                 virtio_cread(vdev, struct virtio_blk_config,
1344                              max_write_zeroes_sectors, &v);
1345                 lim->max_write_zeroes_sectors = v ? v : UINT_MAX;
1346         }
1347
1348         /* The discard and secure erase limits are combined since the Linux
1349          * block layer uses the same limit for both commands.
1350          *
1351          * If both VIRTIO_BLK_F_SECURE_ERASE and VIRTIO_BLK_F_DISCARD features
1352          * are negotiated, we will use the minimum between the limits.
1353          *
1354          * discard sector alignment is set to the minimum between discard_sector_alignment
1355          * and secure_erase_sector_alignment.
1356          *
1357          * max discard sectors is set to the minimum between max_discard_seg and
1358          * max_secure_erase_seg.
1359          */
1360         if (virtio_has_feature(vdev, VIRTIO_BLK_F_SECURE_ERASE)) {
1361
1362                 virtio_cread(vdev, struct virtio_blk_config,
1363                              secure_erase_sector_alignment, &v);
1364
1365                 /* secure_erase_sector_alignment should not be zero, the device should set a
1366                  * valid number of sectors.
1367                  */
1368                 if (!v) {
1369                         dev_err(&vdev->dev,
1370                                 "virtio_blk: secure_erase_sector_alignment can't be 0\n");
1371                         return -EINVAL;
1372                 }
1373
1374                 discard_granularity = min_not_zero(discard_granularity, v);
1375
1376                 virtio_cread(vdev, struct virtio_blk_config,
1377                              max_secure_erase_sectors, &v);
1378
1379                 /* max_secure_erase_sectors should not be zero, the device should set a
1380                  * valid number of sectors.
1381                  */
1382                 if (!v) {
1383                         dev_err(&vdev->dev,
1384                                 "virtio_blk: max_secure_erase_sectors can't be 0\n");
1385                         return -EINVAL;
1386                 }
1387
1388                 lim->max_secure_erase_sectors = v;
1389
1390                 virtio_cread(vdev, struct virtio_blk_config,
1391                              max_secure_erase_seg, &v);
1392
1393                 /* max_secure_erase_seg should not be zero, the device should set a
1394                  * valid number of segments
1395                  */
1396                 if (!v) {
1397                         dev_err(&vdev->dev,
1398                                 "virtio_blk: max_secure_erase_seg can't be 0\n");
1399                         return -EINVAL;
1400                 }
1401
1402                 max_discard_segs = min_not_zero(max_discard_segs, v);
1403         }
1404
1405         if (virtio_has_feature(vdev, VIRTIO_BLK_F_DISCARD) ||
1406             virtio_has_feature(vdev, VIRTIO_BLK_F_SECURE_ERASE)) {
1407                 /* max_discard_seg and discard_granularity will be 0 only
1408                  * if max_discard_seg and discard_sector_alignment fields in the virtio
1409                  * config are 0 and VIRTIO_BLK_F_SECURE_ERASE feature is not negotiated.
1410                  * In this case, we use default values.
1411                  */
1412                 if (!max_discard_segs)
1413                         max_discard_segs = sg_elems;
1414
1415                 lim->max_discard_segments =
1416                         min(max_discard_segs, MAX_DISCARD_SEGMENTS);
1417
1418                 if (discard_granularity)
1419                         lim->discard_granularity =
1420                                 discard_granularity << SECTOR_SHIFT;
1421                 else
1422                         lim->discard_granularity = blk_size;
1423         }
1424
1425         if (virtio_has_feature(vdev, VIRTIO_BLK_F_ZONED)) {
1426                 u8 model;
1427
1428                 virtio_cread(vdev, struct virtio_blk_config, zoned.model, &model);
1429                 switch (model) {
1430                 case VIRTIO_BLK_Z_NONE:
1431                 case VIRTIO_BLK_Z_HA:
1432                         /* treat host-aware devices as non-zoned */
1433                         return 0;
1434                 case VIRTIO_BLK_Z_HM:
1435                         err = virtblk_read_zoned_limits(vblk, lim);
1436                         if (err)
1437                                 return err;
1438                         break;
1439                 default:
1440                         dev_err(&vdev->dev, "unsupported zone model %d\n", model);
1441                         return -EINVAL;
1442                 }
1443         }
1444
1445         return 0;
1446 }
1447
1448 static int virtblk_probe(struct virtio_device *vdev)
1449 {
1450         struct virtio_blk *vblk;
1451         struct queue_limits lim = { };
1452         int err, index;
1453         unsigned int queue_depth;
1454
1455         if (!vdev->config->get) {
1456                 dev_err(&vdev->dev, "%s failure: config access disabled\n",
1457                         __func__);
1458                 return -EINVAL;
1459         }
1460
1461         err = ida_alloc_range(&vd_index_ida, 0,
1462                               minor_to_index(1 << MINORBITS) - 1, GFP_KERNEL);
1463         if (err < 0)
1464                 goto out;
1465         index = err;
1466
1467         vdev->priv = vblk = kmalloc(sizeof(*vblk), GFP_KERNEL);
1468         if (!vblk) {
1469                 err = -ENOMEM;
1470                 goto out_free_index;
1471         }
1472
1473         mutex_init(&vblk->vdev_mutex);
1474
1475         vblk->vdev = vdev;
1476
1477         INIT_WORK(&vblk->config_work, virtblk_config_changed_work);
1478
1479         err = init_vq(vblk);
1480         if (err)
1481                 goto out_free_vblk;
1482
1483         /* Default queue sizing is to fill the ring. */
1484         if (!virtblk_queue_depth) {
1485                 queue_depth = vblk->vqs[0].vq->num_free;
1486                 /* ... but without indirect descs, we use 2 descs per req */
1487                 if (!virtio_has_feature(vdev, VIRTIO_RING_F_INDIRECT_DESC))
1488                         queue_depth /= 2;
1489         } else {
1490                 queue_depth = virtblk_queue_depth;
1491         }
1492
1493         memset(&vblk->tag_set, 0, sizeof(vblk->tag_set));
1494         vblk->tag_set.ops = &virtio_mq_ops;
1495         vblk->tag_set.queue_depth = queue_depth;
1496         vblk->tag_set.numa_node = NUMA_NO_NODE;
1497         vblk->tag_set.flags = BLK_MQ_F_SHOULD_MERGE;
1498         vblk->tag_set.cmd_size =
1499                 sizeof(struct virtblk_req) +
1500                 sizeof(struct scatterlist) * VIRTIO_BLK_INLINE_SG_CNT;
1501         vblk->tag_set.driver_data = vblk;
1502         vblk->tag_set.nr_hw_queues = vblk->num_vqs;
1503         vblk->tag_set.nr_maps = 1;
1504         if (vblk->io_queues[HCTX_TYPE_POLL])
1505                 vblk->tag_set.nr_maps = 3;
1506
1507         err = blk_mq_alloc_tag_set(&vblk->tag_set);
1508         if (err)
1509                 goto out_free_vq;
1510
1511         err = virtblk_read_limits(vblk, &lim);
1512         if (err)
1513                 goto out_free_tags;
1514
1515         vblk->disk = blk_mq_alloc_disk(&vblk->tag_set, &lim, vblk);
1516         if (IS_ERR(vblk->disk)) {
1517                 err = PTR_ERR(vblk->disk);
1518                 goto out_free_tags;
1519         }
1520
1521         virtblk_name_format("vd", index, vblk->disk->disk_name, DISK_NAME_LEN);
1522
1523         vblk->disk->major = major;
1524         vblk->disk->first_minor = index_to_minor(index);
1525         vblk->disk->minors = 1 << PART_BITS;
1526         vblk->disk->private_data = vblk;
1527         vblk->disk->fops = &virtblk_fops;
1528         vblk->index = index;
1529
1530         /* configure queue flush support */
1531         virtblk_update_cache_mode(vdev);
1532
1533         /* If disk is read-only in the host, the guest should obey */
1534         if (virtio_has_feature(vdev, VIRTIO_BLK_F_RO))
1535                 set_disk_ro(vblk->disk, 1);
1536
1537         virtblk_update_capacity(vblk, false);
1538         virtio_device_ready(vdev);
1539
1540         /*
1541          * All steps that follow use the VQs therefore they need to be
1542          * placed after the virtio_device_ready() call above.
1543          */
1544         if (IS_ENABLED(CONFIG_BLK_DEV_ZONED) && lim.zoned) {
1545                 blk_queue_flag_set(QUEUE_FLAG_ZONE_RESETALL, vblk->disk->queue);
1546                 err = blk_revalidate_disk_zones(vblk->disk);
1547                 if (err)
1548                         goto out_cleanup_disk;
1549         }
1550
1551         err = device_add_disk(&vdev->dev, vblk->disk, virtblk_attr_groups);
1552         if (err)
1553                 goto out_cleanup_disk;
1554
1555         return 0;
1556
1557 out_cleanup_disk:
1558         put_disk(vblk->disk);
1559 out_free_tags:
1560         blk_mq_free_tag_set(&vblk->tag_set);
1561 out_free_vq:
1562         vdev->config->del_vqs(vdev);
1563         kfree(vblk->vqs);
1564 out_free_vblk:
1565         kfree(vblk);
1566 out_free_index:
1567         ida_free(&vd_index_ida, index);
1568 out:
1569         return err;
1570 }
1571
1572 static void virtblk_remove(struct virtio_device *vdev)
1573 {
1574         struct virtio_blk *vblk = vdev->priv;
1575
1576         /* Make sure no work handler is accessing the device. */
1577         flush_work(&vblk->config_work);
1578
1579         del_gendisk(vblk->disk);
1580         blk_mq_free_tag_set(&vblk->tag_set);
1581
1582         mutex_lock(&vblk->vdev_mutex);
1583
1584         /* Stop all the virtqueues. */
1585         virtio_reset_device(vdev);
1586
1587         /* Virtqueues are stopped, nothing can use vblk->vdev anymore. */
1588         vblk->vdev = NULL;
1589
1590         vdev->config->del_vqs(vdev);
1591         kfree(vblk->vqs);
1592
1593         mutex_unlock(&vblk->vdev_mutex);
1594
1595         put_disk(vblk->disk);
1596 }
1597
1598 #ifdef CONFIG_PM_SLEEP
1599 static int virtblk_freeze(struct virtio_device *vdev)
1600 {
1601         struct virtio_blk *vblk = vdev->priv;
1602
1603         /* Ensure no requests in virtqueues before deleting vqs. */
1604         blk_mq_freeze_queue(vblk->disk->queue);
1605
1606         /* Ensure we don't receive any more interrupts */
1607         virtio_reset_device(vdev);
1608
1609         /* Make sure no work handler is accessing the device. */
1610         flush_work(&vblk->config_work);
1611
1612         vdev->config->del_vqs(vdev);
1613         kfree(vblk->vqs);
1614
1615         return 0;
1616 }
1617
1618 static int virtblk_restore(struct virtio_device *vdev)
1619 {
1620         struct virtio_blk *vblk = vdev->priv;
1621         int ret;
1622
1623         ret = init_vq(vdev->priv);
1624         if (ret)
1625                 return ret;
1626
1627         virtio_device_ready(vdev);
1628
1629         blk_mq_unfreeze_queue(vblk->disk->queue);
1630         return 0;
1631 }
1632 #endif
1633
1634 static const struct virtio_device_id id_table[] = {
1635         { VIRTIO_ID_BLOCK, VIRTIO_DEV_ANY_ID },
1636         { 0 },
1637 };
1638
1639 static unsigned int features_legacy[] = {
1640         VIRTIO_BLK_F_SEG_MAX, VIRTIO_BLK_F_SIZE_MAX, VIRTIO_BLK_F_GEOMETRY,
1641         VIRTIO_BLK_F_RO, VIRTIO_BLK_F_BLK_SIZE,
1642         VIRTIO_BLK_F_FLUSH, VIRTIO_BLK_F_TOPOLOGY, VIRTIO_BLK_F_CONFIG_WCE,
1643         VIRTIO_BLK_F_MQ, VIRTIO_BLK_F_DISCARD, VIRTIO_BLK_F_WRITE_ZEROES,
1644         VIRTIO_BLK_F_SECURE_ERASE,
1645 }
1646 ;
1647 static unsigned int features[] = {
1648         VIRTIO_BLK_F_SEG_MAX, VIRTIO_BLK_F_SIZE_MAX, VIRTIO_BLK_F_GEOMETRY,
1649         VIRTIO_BLK_F_RO, VIRTIO_BLK_F_BLK_SIZE,
1650         VIRTIO_BLK_F_FLUSH, VIRTIO_BLK_F_TOPOLOGY, VIRTIO_BLK_F_CONFIG_WCE,
1651         VIRTIO_BLK_F_MQ, VIRTIO_BLK_F_DISCARD, VIRTIO_BLK_F_WRITE_ZEROES,
1652         VIRTIO_BLK_F_SECURE_ERASE, VIRTIO_BLK_F_ZONED,
1653 };
1654
1655 static struct virtio_driver virtio_blk = {
1656         .feature_table                  = features,
1657         .feature_table_size             = ARRAY_SIZE(features),
1658         .feature_table_legacy           = features_legacy,
1659         .feature_table_size_legacy      = ARRAY_SIZE(features_legacy),
1660         .driver.name                    = KBUILD_MODNAME,
1661         .driver.owner                   = THIS_MODULE,
1662         .id_table                       = id_table,
1663         .probe                          = virtblk_probe,
1664         .remove                         = virtblk_remove,
1665         .config_changed                 = virtblk_config_changed,
1666 #ifdef CONFIG_PM_SLEEP
1667         .freeze                         = virtblk_freeze,
1668         .restore                        = virtblk_restore,
1669 #endif
1670 };
1671
1672 static int __init virtio_blk_init(void)
1673 {
1674         int error;
1675
1676         virtblk_wq = alloc_workqueue("virtio-blk", 0, 0);
1677         if (!virtblk_wq)
1678                 return -ENOMEM;
1679
1680         major = register_blkdev(0, "virtblk");
1681         if (major < 0) {
1682                 error = major;
1683                 goto out_destroy_workqueue;
1684         }
1685
1686         error = register_virtio_driver(&virtio_blk);
1687         if (error)
1688                 goto out_unregister_blkdev;
1689         return 0;
1690
1691 out_unregister_blkdev:
1692         unregister_blkdev(major, "virtblk");
1693 out_destroy_workqueue:
1694         destroy_workqueue(virtblk_wq);
1695         return error;
1696 }
1697
1698 static void __exit virtio_blk_fini(void)
1699 {
1700         unregister_virtio_driver(&virtio_blk);
1701         unregister_blkdev(major, "virtblk");
1702         destroy_workqueue(virtblk_wq);
1703 }
1704 module_init(virtio_blk_init);
1705 module_exit(virtio_blk_fini);
1706
1707 MODULE_DEVICE_TABLE(virtio, id_table);
1708 MODULE_DESCRIPTION("Virtio block driver");
1709 MODULE_LICENSE("GPL");