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 19 #define PART_BITS 4 20 #define VQ_NAME_LEN 16 21 #define MAX_DISCARD_SEGMENTS 256u 22 23 static int major; 24 static DEFINE_IDA(vd_index_ida); 25 26 static struct workqueue_struct *virtblk_wq; 27 28 struct virtio_blk_vq { 29 struct virtqueue *vq; 30 spinlock_t lock; 31 char name[VQ_NAME_LEN]; 32 } ____cacheline_aligned_in_smp; 33 34 struct virtio_blk { 35 struct virtio_device *vdev; 36 37 /* The disk structure for the kernel. */ 38 struct gendisk *disk; 39 40 /* Block layer tags. */ 41 struct blk_mq_tag_set tag_set; 42 43 /* Process context for config space updates */ 44 struct work_struct config_work; 45 46 /* What host tells us, plus 2 for header & tailer. */ 47 unsigned int sg_elems; 48 49 /* Ida index - used to track minor number allocations. */ 50 int index; 51 52 /* num of vqs */ 53 int num_vqs; 54 struct virtio_blk_vq *vqs; 55 }; 56 57 struct virtblk_req { 58 struct virtio_blk_outhdr out_hdr; 59 u8 status; 60 struct scatterlist sg[]; 61 }; 62 63 static inline blk_status_t virtblk_result(struct virtblk_req *vbr) 64 { 65 switch (vbr->status) { 66 case VIRTIO_BLK_S_OK: 67 return BLK_STS_OK; 68 case VIRTIO_BLK_S_UNSUPP: 69 return BLK_STS_NOTSUPP; 70 default: 71 return BLK_STS_IOERR; 72 } 73 } 74 75 static int virtblk_add_req(struct virtqueue *vq, struct virtblk_req *vbr, 76 struct scatterlist *data_sg, bool have_data) 77 { 78 struct scatterlist hdr, status, *sgs[3]; 79 unsigned int num_out = 0, num_in = 0; 80 81 sg_init_one(&hdr, &vbr->out_hdr, sizeof(vbr->out_hdr)); 82 sgs[num_out++] = &hdr; 83 84 if (have_data) { 85 if (vbr->out_hdr.type & cpu_to_virtio32(vq->vdev, VIRTIO_BLK_T_OUT)) 86 sgs[num_out++] = data_sg; 87 else 88 sgs[num_out + num_in++] = data_sg; 89 } 90 91 sg_init_one(&status, &vbr->status, sizeof(vbr->status)); 92 sgs[num_out + num_in++] = &status; 93 94 return virtqueue_add_sgs(vq, sgs, num_out, num_in, vbr, GFP_ATOMIC); 95 } 96 97 static int virtblk_setup_discard_write_zeroes(struct request *req, bool unmap) 98 { 99 unsigned short segments = blk_rq_nr_discard_segments(req); 100 unsigned short n = 0; 101 struct virtio_blk_discard_write_zeroes *range; 102 struct bio *bio; 103 u32 flags = 0; 104 105 if (unmap) 106 flags |= VIRTIO_BLK_WRITE_ZEROES_FLAG_UNMAP; 107 108 range = kmalloc_array(segments, sizeof(*range), GFP_ATOMIC); 109 if (!range) 110 return -ENOMEM; 111 112 __rq_for_each_bio(bio, req) { 113 u64 sector = bio->bi_iter.bi_sector; 114 u32 num_sectors = bio->bi_iter.bi_size >> SECTOR_SHIFT; 115 116 range[n].flags = cpu_to_le32(flags); 117 range[n].num_sectors = cpu_to_le32(num_sectors); 118 range[n].sector = cpu_to_le64(sector); 119 n++; 120 } 121 122 req->special_vec.bv_page = virt_to_page(range); 123 req->special_vec.bv_offset = offset_in_page(range); 124 req->special_vec.bv_len = sizeof(*range) * segments; 125 req->rq_flags |= RQF_SPECIAL_PAYLOAD; 126 127 return 0; 128 } 129 130 static inline void virtblk_request_done(struct request *req) 131 { 132 struct virtblk_req *vbr = blk_mq_rq_to_pdu(req); 133 134 if (req->rq_flags & RQF_SPECIAL_PAYLOAD) { 135 kfree(page_address(req->special_vec.bv_page) + 136 req->special_vec.bv_offset); 137 } 138 139 blk_mq_end_request(req, virtblk_result(vbr)); 140 } 141 142 static void virtblk_done(struct virtqueue *vq) 143 { 144 struct virtio_blk *vblk = vq->vdev->priv; 145 bool req_done = false; 146 int qid = vq->index; 147 struct virtblk_req *vbr; 148 unsigned long flags; 149 unsigned int len; 150 151 spin_lock_irqsave(&vblk->vqs[qid].lock, flags); 152 do { 153 virtqueue_disable_cb(vq); 154 while ((vbr = virtqueue_get_buf(vblk->vqs[qid].vq, &len)) != NULL) { 155 struct request *req = blk_mq_rq_from_pdu(vbr); 156 157 blk_mq_complete_request(req); 158 req_done = true; 159 } 160 if (unlikely(virtqueue_is_broken(vq))) 161 break; 162 } while (!virtqueue_enable_cb(vq)); 163 164 /* In case queue is stopped waiting for more buffers. */ 165 if (req_done) 166 blk_mq_start_stopped_hw_queues(vblk->disk->queue, true); 167 spin_unlock_irqrestore(&vblk->vqs[qid].lock, flags); 168 } 169 170 static void virtio_commit_rqs(struct blk_mq_hw_ctx *hctx) 171 { 172 struct virtio_blk *vblk = hctx->queue->queuedata; 173 struct virtio_blk_vq *vq = &vblk->vqs[hctx->queue_num]; 174 bool kick; 175 176 spin_lock_irq(&vq->lock); 177 kick = virtqueue_kick_prepare(vq->vq); 178 spin_unlock_irq(&vq->lock); 179 180 if (kick) 181 virtqueue_notify(vq->vq); 182 } 183 184 static blk_status_t virtio_queue_rq(struct blk_mq_hw_ctx *hctx, 185 const struct blk_mq_queue_data *bd) 186 { 187 struct virtio_blk *vblk = hctx->queue->queuedata; 188 struct request *req = bd->rq; 189 struct virtblk_req *vbr = blk_mq_rq_to_pdu(req); 190 unsigned long flags; 191 unsigned int num; 192 int qid = hctx->queue_num; 193 int err; 194 bool notify = false; 195 bool unmap = false; 196 u32 type; 197 198 BUG_ON(req->nr_phys_segments + 2 > vblk->sg_elems); 199 200 switch (req_op(req)) { 201 case REQ_OP_READ: 202 case REQ_OP_WRITE: 203 type = 0; 204 break; 205 case REQ_OP_FLUSH: 206 type = VIRTIO_BLK_T_FLUSH; 207 break; 208 case REQ_OP_DISCARD: 209 type = VIRTIO_BLK_T_DISCARD; 210 break; 211 case REQ_OP_WRITE_ZEROES: 212 type = VIRTIO_BLK_T_WRITE_ZEROES; 213 unmap = !(req->cmd_flags & REQ_NOUNMAP); 214 break; 215 case REQ_OP_DRV_IN: 216 type = VIRTIO_BLK_T_GET_ID; 217 break; 218 default: 219 WARN_ON_ONCE(1); 220 return BLK_STS_IOERR; 221 } 222 223 vbr->out_hdr.type = cpu_to_virtio32(vblk->vdev, type); 224 vbr->out_hdr.sector = type ? 225 0 : cpu_to_virtio64(vblk->vdev, blk_rq_pos(req)); 226 vbr->out_hdr.ioprio = cpu_to_virtio32(vblk->vdev, req_get_ioprio(req)); 227 228 blk_mq_start_request(req); 229 230 if (type == VIRTIO_BLK_T_DISCARD || type == VIRTIO_BLK_T_WRITE_ZEROES) { 231 err = virtblk_setup_discard_write_zeroes(req, unmap); 232 if (err) 233 return BLK_STS_RESOURCE; 234 } 235 236 num = blk_rq_map_sg(hctx->queue, req, vbr->sg); 237 if (num) { 238 if (rq_data_dir(req) == WRITE) 239 vbr->out_hdr.type |= cpu_to_virtio32(vblk->vdev, VIRTIO_BLK_T_OUT); 240 else 241 vbr->out_hdr.type |= cpu_to_virtio32(vblk->vdev, VIRTIO_BLK_T_IN); 242 } 243 244 spin_lock_irqsave(&vblk->vqs[qid].lock, flags); 245 err = virtblk_add_req(vblk->vqs[qid].vq, vbr, vbr->sg, num); 246 if (err) { 247 virtqueue_kick(vblk->vqs[qid].vq); 248 /* Don't stop the queue if -ENOMEM: we may have failed to 249 * bounce the buffer due to global resource outage. 250 */ 251 if (err == -ENOSPC) 252 blk_mq_stop_hw_queue(hctx); 253 spin_unlock_irqrestore(&vblk->vqs[qid].lock, flags); 254 switch (err) { 255 case -ENOSPC: 256 return BLK_STS_DEV_RESOURCE; 257 case -ENOMEM: 258 return BLK_STS_RESOURCE; 259 default: 260 return BLK_STS_IOERR; 261 } 262 } 263 264 if (bd->last && virtqueue_kick_prepare(vblk->vqs[qid].vq)) 265 notify = true; 266 spin_unlock_irqrestore(&vblk->vqs[qid].lock, flags); 267 268 if (notify) 269 virtqueue_notify(vblk->vqs[qid].vq); 270 return BLK_STS_OK; 271 } 272 273 /* return id (s/n) string for *disk to *id_str 274 */ 275 static int virtblk_get_id(struct gendisk *disk, char *id_str) 276 { 277 struct virtio_blk *vblk = disk->private_data; 278 struct request_queue *q = vblk->disk->queue; 279 struct request *req; 280 int err; 281 282 req = blk_get_request(q, REQ_OP_DRV_IN, 0); 283 if (IS_ERR(req)) 284 return PTR_ERR(req); 285 286 err = blk_rq_map_kern(q, req, id_str, VIRTIO_BLK_ID_BYTES, GFP_KERNEL); 287 if (err) 288 goto out; 289 290 blk_execute_rq(vblk->disk->queue, vblk->disk, req, false); 291 err = blk_status_to_errno(virtblk_result(blk_mq_rq_to_pdu(req))); 292 out: 293 blk_put_request(req); 294 return err; 295 } 296 297 /* We provide getgeo only to please some old bootloader/partitioning tools */ 298 static int virtblk_getgeo(struct block_device *bd, struct hd_geometry *geo) 299 { 300 struct virtio_blk *vblk = bd->bd_disk->private_data; 301 302 /* see if the host passed in geometry config */ 303 if (virtio_has_feature(vblk->vdev, VIRTIO_BLK_F_GEOMETRY)) { 304 virtio_cread(vblk->vdev, struct virtio_blk_config, 305 geometry.cylinders, &geo->cylinders); 306 virtio_cread(vblk->vdev, struct virtio_blk_config, 307 geometry.heads, &geo->heads); 308 virtio_cread(vblk->vdev, struct virtio_blk_config, 309 geometry.sectors, &geo->sectors); 310 } else { 311 /* some standard values, similar to sd */ 312 geo->heads = 1 << 6; 313 geo->sectors = 1 << 5; 314 geo->cylinders = get_capacity(bd->bd_disk) >> 11; 315 } 316 return 0; 317 } 318 319 static const struct block_device_operations virtblk_fops = { 320 .owner = THIS_MODULE, 321 .getgeo = virtblk_getgeo, 322 }; 323 324 static int index_to_minor(int index) 325 { 326 return index << PART_BITS; 327 } 328 329 static int minor_to_index(int minor) 330 { 331 return minor >> PART_BITS; 332 } 333 334 static ssize_t serial_show(struct device *dev, 335 struct device_attribute *attr, char *buf) 336 { 337 struct gendisk *disk = dev_to_disk(dev); 338 int err; 339 340 /* sysfs gives us a PAGE_SIZE buffer */ 341 BUILD_BUG_ON(PAGE_SIZE < VIRTIO_BLK_ID_BYTES); 342 343 buf[VIRTIO_BLK_ID_BYTES] = '\0'; 344 err = virtblk_get_id(disk, buf); 345 if (!err) 346 return strlen(buf); 347 348 if (err == -EIO) /* Unsupported? Make it empty. */ 349 return 0; 350 351 return err; 352 } 353 354 static DEVICE_ATTR_RO(serial); 355 356 /* The queue's logical block size must be set before calling this */ 357 static void virtblk_update_capacity(struct virtio_blk *vblk, bool resize) 358 { 359 struct virtio_device *vdev = vblk->vdev; 360 struct request_queue *q = vblk->disk->queue; 361 char cap_str_2[10], cap_str_10[10]; 362 unsigned long long nblocks; 363 u64 capacity; 364 365 /* Host must always specify the capacity. */ 366 virtio_cread(vdev, struct virtio_blk_config, capacity, &capacity); 367 368 /* If capacity is too big, truncate with warning. */ 369 if ((sector_t)capacity != capacity) { 370 dev_warn(&vdev->dev, "Capacity %llu too large: truncating\n", 371 (unsigned long long)capacity); 372 capacity = (sector_t)-1; 373 } 374 375 nblocks = DIV_ROUND_UP_ULL(capacity, queue_logical_block_size(q) >> 9); 376 377 string_get_size(nblocks, queue_logical_block_size(q), 378 STRING_UNITS_2, cap_str_2, sizeof(cap_str_2)); 379 string_get_size(nblocks, queue_logical_block_size(q), 380 STRING_UNITS_10, cap_str_10, sizeof(cap_str_10)); 381 382 dev_notice(&vdev->dev, 383 "[%s] %s%llu %d-byte logical blocks (%s/%s)\n", 384 vblk->disk->disk_name, 385 resize ? "new size: " : "", 386 nblocks, 387 queue_logical_block_size(q), 388 cap_str_10, 389 cap_str_2); 390 391 set_capacity_revalidate_and_notify(vblk->disk, capacity, true); 392 } 393 394 static void virtblk_config_changed_work(struct work_struct *work) 395 { 396 struct virtio_blk *vblk = 397 container_of(work, struct virtio_blk, config_work); 398 399 virtblk_update_capacity(vblk, true); 400 } 401 402 static void virtblk_config_changed(struct virtio_device *vdev) 403 { 404 struct virtio_blk *vblk = vdev->priv; 405 406 queue_work(virtblk_wq, &vblk->config_work); 407 } 408 409 static int init_vq(struct virtio_blk *vblk) 410 { 411 int err; 412 int i; 413 vq_callback_t **callbacks; 414 const char **names; 415 struct virtqueue **vqs; 416 unsigned short num_vqs; 417 struct virtio_device *vdev = vblk->vdev; 418 struct irq_affinity desc = { 0, }; 419 420 err = virtio_cread_feature(vdev, VIRTIO_BLK_F_MQ, 421 struct virtio_blk_config, num_queues, 422 &num_vqs); 423 if (err) 424 num_vqs = 1; 425 426 num_vqs = min_t(unsigned int, nr_cpu_ids, num_vqs); 427 428 vblk->vqs = kmalloc_array(num_vqs, sizeof(*vblk->vqs), GFP_KERNEL); 429 if (!vblk->vqs) 430 return -ENOMEM; 431 432 names = kmalloc_array(num_vqs, sizeof(*names), GFP_KERNEL); 433 callbacks = kmalloc_array(num_vqs, sizeof(*callbacks), GFP_KERNEL); 434 vqs = kmalloc_array(num_vqs, sizeof(*vqs), GFP_KERNEL); 435 if (!names || !callbacks || !vqs) { 436 err = -ENOMEM; 437 goto out; 438 } 439 440 for (i = 0; i < num_vqs; i++) { 441 callbacks[i] = virtblk_done; 442 snprintf(vblk->vqs[i].name, VQ_NAME_LEN, "req.%d", i); 443 names[i] = vblk->vqs[i].name; 444 } 445 446 /* Discover virtqueues and write information to configuration. */ 447 err = virtio_find_vqs(vdev, num_vqs, vqs, callbacks, names, &desc); 448 if (err) 449 goto out; 450 451 for (i = 0; i < num_vqs; i++) { 452 spin_lock_init(&vblk->vqs[i].lock); 453 vblk->vqs[i].vq = vqs[i]; 454 } 455 vblk->num_vqs = num_vqs; 456 457 out: 458 kfree(vqs); 459 kfree(callbacks); 460 kfree(names); 461 if (err) 462 kfree(vblk->vqs); 463 return err; 464 } 465 466 /* 467 * Legacy naming scheme used for virtio devices. We are stuck with it for 468 * virtio blk but don't ever use it for any new driver. 469 */ 470 static int virtblk_name_format(char *prefix, int index, char *buf, int buflen) 471 { 472 const int base = 'z' - 'a' + 1; 473 char *begin = buf + strlen(prefix); 474 char *end = buf + buflen; 475 char *p; 476 int unit; 477 478 p = end - 1; 479 *p = '\0'; 480 unit = base; 481 do { 482 if (p == begin) 483 return -EINVAL; 484 *--p = 'a' + (index % unit); 485 index = (index / unit) - 1; 486 } while (index >= 0); 487 488 memmove(begin, p, end - p); 489 memcpy(buf, prefix, strlen(prefix)); 490 491 return 0; 492 } 493 494 static int virtblk_get_cache_mode(struct virtio_device *vdev) 495 { 496 u8 writeback; 497 int err; 498 499 err = virtio_cread_feature(vdev, VIRTIO_BLK_F_CONFIG_WCE, 500 struct virtio_blk_config, wce, 501 &writeback); 502 503 /* 504 * If WCE is not configurable and flush is not available, 505 * assume no writeback cache is in use. 506 */ 507 if (err) 508 writeback = virtio_has_feature(vdev, VIRTIO_BLK_F_FLUSH); 509 510 return writeback; 511 } 512 513 static void virtblk_update_cache_mode(struct virtio_device *vdev) 514 { 515 u8 writeback = virtblk_get_cache_mode(vdev); 516 struct virtio_blk *vblk = vdev->priv; 517 518 blk_queue_write_cache(vblk->disk->queue, writeback, false); 519 revalidate_disk(vblk->disk); 520 } 521 522 static const char *const virtblk_cache_types[] = { 523 "write through", "write back" 524 }; 525 526 static ssize_t 527 cache_type_store(struct device *dev, struct device_attribute *attr, 528 const char *buf, size_t count) 529 { 530 struct gendisk *disk = dev_to_disk(dev); 531 struct virtio_blk *vblk = disk->private_data; 532 struct virtio_device *vdev = vblk->vdev; 533 int i; 534 535 BUG_ON(!virtio_has_feature(vblk->vdev, VIRTIO_BLK_F_CONFIG_WCE)); 536 i = sysfs_match_string(virtblk_cache_types, buf); 537 if (i < 0) 538 return i; 539 540 virtio_cwrite8(vdev, offsetof(struct virtio_blk_config, wce), i); 541 virtblk_update_cache_mode(vdev); 542 return count; 543 } 544 545 static ssize_t 546 cache_type_show(struct device *dev, struct device_attribute *attr, char *buf) 547 { 548 struct gendisk *disk = dev_to_disk(dev); 549 struct virtio_blk *vblk = disk->private_data; 550 u8 writeback = virtblk_get_cache_mode(vblk->vdev); 551 552 BUG_ON(writeback >= ARRAY_SIZE(virtblk_cache_types)); 553 return snprintf(buf, 40, "%s\n", virtblk_cache_types[writeback]); 554 } 555 556 static DEVICE_ATTR_RW(cache_type); 557 558 static struct attribute *virtblk_attrs[] = { 559 &dev_attr_serial.attr, 560 &dev_attr_cache_type.attr, 561 NULL, 562 }; 563 564 static umode_t virtblk_attrs_are_visible(struct kobject *kobj, 565 struct attribute *a, int n) 566 { 567 struct device *dev = container_of(kobj, struct device, kobj); 568 struct gendisk *disk = dev_to_disk(dev); 569 struct virtio_blk *vblk = disk->private_data; 570 struct virtio_device *vdev = vblk->vdev; 571 572 if (a == &dev_attr_cache_type.attr && 573 !virtio_has_feature(vdev, VIRTIO_BLK_F_CONFIG_WCE)) 574 return S_IRUGO; 575 576 return a->mode; 577 } 578 579 static const struct attribute_group virtblk_attr_group = { 580 .attrs = virtblk_attrs, 581 .is_visible = virtblk_attrs_are_visible, 582 }; 583 584 static const struct attribute_group *virtblk_attr_groups[] = { 585 &virtblk_attr_group, 586 NULL, 587 }; 588 589 static int virtblk_init_request(struct blk_mq_tag_set *set, struct request *rq, 590 unsigned int hctx_idx, unsigned int numa_node) 591 { 592 struct virtio_blk *vblk = set->driver_data; 593 struct virtblk_req *vbr = blk_mq_rq_to_pdu(rq); 594 595 sg_init_table(vbr->sg, vblk->sg_elems); 596 return 0; 597 } 598 599 static int virtblk_map_queues(struct blk_mq_tag_set *set) 600 { 601 struct virtio_blk *vblk = set->driver_data; 602 603 return blk_mq_virtio_map_queues(&set->map[HCTX_TYPE_DEFAULT], 604 vblk->vdev, 0); 605 } 606 607 static const struct blk_mq_ops virtio_mq_ops = { 608 .queue_rq = virtio_queue_rq, 609 .commit_rqs = virtio_commit_rqs, 610 .complete = virtblk_request_done, 611 .init_request = virtblk_init_request, 612 .map_queues = virtblk_map_queues, 613 }; 614 615 static unsigned int virtblk_queue_depth; 616 module_param_named(queue_depth, virtblk_queue_depth, uint, 0444); 617 618 static int virtblk_probe(struct virtio_device *vdev) 619 { 620 struct virtio_blk *vblk; 621 struct request_queue *q; 622 int err, index; 623 624 u32 v, blk_size, max_size, sg_elems, opt_io_size; 625 u16 min_io_size; 626 u8 physical_block_exp, alignment_offset; 627 628 if (!vdev->config->get) { 629 dev_err(&vdev->dev, "%s failure: config access disabled\n", 630 __func__); 631 return -EINVAL; 632 } 633 634 err = ida_simple_get(&vd_index_ida, 0, minor_to_index(1 << MINORBITS), 635 GFP_KERNEL); 636 if (err < 0) 637 goto out; 638 index = err; 639 640 /* We need to know how many segments before we allocate. */ 641 err = virtio_cread_feature(vdev, VIRTIO_BLK_F_SEG_MAX, 642 struct virtio_blk_config, seg_max, 643 &sg_elems); 644 645 /* We need at least one SG element, whatever they say. */ 646 if (err || !sg_elems) 647 sg_elems = 1; 648 649 /* We need an extra sg elements at head and tail. */ 650 sg_elems += 2; 651 vdev->priv = vblk = kmalloc(sizeof(*vblk), GFP_KERNEL); 652 if (!vblk) { 653 err = -ENOMEM; 654 goto out_free_index; 655 } 656 657 vblk->vdev = vdev; 658 vblk->sg_elems = sg_elems; 659 660 INIT_WORK(&vblk->config_work, virtblk_config_changed_work); 661 662 err = init_vq(vblk); 663 if (err) 664 goto out_free_vblk; 665 666 /* FIXME: How many partitions? How long is a piece of string? */ 667 vblk->disk = alloc_disk(1 << PART_BITS); 668 if (!vblk->disk) { 669 err = -ENOMEM; 670 goto out_free_vq; 671 } 672 673 /* Default queue sizing is to fill the ring. */ 674 if (!virtblk_queue_depth) { 675 virtblk_queue_depth = vblk->vqs[0].vq->num_free; 676 /* ... but without indirect descs, we use 2 descs per req */ 677 if (!virtio_has_feature(vdev, VIRTIO_RING_F_INDIRECT_DESC)) 678 virtblk_queue_depth /= 2; 679 } 680 681 memset(&vblk->tag_set, 0, sizeof(vblk->tag_set)); 682 vblk->tag_set.ops = &virtio_mq_ops; 683 vblk->tag_set.queue_depth = virtblk_queue_depth; 684 vblk->tag_set.numa_node = NUMA_NO_NODE; 685 vblk->tag_set.flags = BLK_MQ_F_SHOULD_MERGE; 686 vblk->tag_set.cmd_size = 687 sizeof(struct virtblk_req) + 688 sizeof(struct scatterlist) * sg_elems; 689 vblk->tag_set.driver_data = vblk; 690 vblk->tag_set.nr_hw_queues = vblk->num_vqs; 691 692 err = blk_mq_alloc_tag_set(&vblk->tag_set); 693 if (err) 694 goto out_put_disk; 695 696 q = blk_mq_init_queue(&vblk->tag_set); 697 if (IS_ERR(q)) { 698 err = -ENOMEM; 699 goto out_free_tags; 700 } 701 vblk->disk->queue = q; 702 703 q->queuedata = vblk; 704 705 virtblk_name_format("vd", index, vblk->disk->disk_name, DISK_NAME_LEN); 706 707 vblk->disk->major = major; 708 vblk->disk->first_minor = index_to_minor(index); 709 vblk->disk->private_data = vblk; 710 vblk->disk->fops = &virtblk_fops; 711 vblk->disk->flags |= GENHD_FL_EXT_DEVT; 712 vblk->index = index; 713 714 /* configure queue flush support */ 715 virtblk_update_cache_mode(vdev); 716 717 /* If disk is read-only in the host, the guest should obey */ 718 if (virtio_has_feature(vdev, VIRTIO_BLK_F_RO)) 719 set_disk_ro(vblk->disk, 1); 720 721 /* We can handle whatever the host told us to handle. */ 722 blk_queue_max_segments(q, vblk->sg_elems-2); 723 724 /* No real sector limit. */ 725 blk_queue_max_hw_sectors(q, -1U); 726 727 max_size = virtio_max_dma_size(vdev); 728 729 /* Host can optionally specify maximum segment size and number of 730 * segments. */ 731 err = virtio_cread_feature(vdev, VIRTIO_BLK_F_SIZE_MAX, 732 struct virtio_blk_config, size_max, &v); 733 if (!err) 734 max_size = min(max_size, v); 735 736 blk_queue_max_segment_size(q, max_size); 737 738 /* Host can optionally specify the block size of the device */ 739 err = virtio_cread_feature(vdev, VIRTIO_BLK_F_BLK_SIZE, 740 struct virtio_blk_config, blk_size, 741 &blk_size); 742 if (!err) 743 blk_queue_logical_block_size(q, blk_size); 744 else 745 blk_size = queue_logical_block_size(q); 746 747 /* Use topology information if available */ 748 err = virtio_cread_feature(vdev, VIRTIO_BLK_F_TOPOLOGY, 749 struct virtio_blk_config, physical_block_exp, 750 &physical_block_exp); 751 if (!err && physical_block_exp) 752 blk_queue_physical_block_size(q, 753 blk_size * (1 << physical_block_exp)); 754 755 err = virtio_cread_feature(vdev, VIRTIO_BLK_F_TOPOLOGY, 756 struct virtio_blk_config, alignment_offset, 757 &alignment_offset); 758 if (!err && alignment_offset) 759 blk_queue_alignment_offset(q, blk_size * alignment_offset); 760 761 err = virtio_cread_feature(vdev, VIRTIO_BLK_F_TOPOLOGY, 762 struct virtio_blk_config, min_io_size, 763 &min_io_size); 764 if (!err && min_io_size) 765 blk_queue_io_min(q, blk_size * min_io_size); 766 767 err = virtio_cread_feature(vdev, VIRTIO_BLK_F_TOPOLOGY, 768 struct virtio_blk_config, opt_io_size, 769 &opt_io_size); 770 if (!err && opt_io_size) 771 blk_queue_io_opt(q, blk_size * opt_io_size); 772 773 if (virtio_has_feature(vdev, VIRTIO_BLK_F_DISCARD)) { 774 q->limits.discard_granularity = blk_size; 775 776 virtio_cread(vdev, struct virtio_blk_config, 777 discard_sector_alignment, &v); 778 q->limits.discard_alignment = v ? v << SECTOR_SHIFT : 0; 779 780 virtio_cread(vdev, struct virtio_blk_config, 781 max_discard_sectors, &v); 782 blk_queue_max_discard_sectors(q, v ? v : UINT_MAX); 783 784 virtio_cread(vdev, struct virtio_blk_config, max_discard_seg, 785 &v); 786 blk_queue_max_discard_segments(q, 787 min_not_zero(v, 788 MAX_DISCARD_SEGMENTS)); 789 790 blk_queue_flag_set(QUEUE_FLAG_DISCARD, q); 791 } 792 793 if (virtio_has_feature(vdev, VIRTIO_BLK_F_WRITE_ZEROES)) { 794 virtio_cread(vdev, struct virtio_blk_config, 795 max_write_zeroes_sectors, &v); 796 blk_queue_max_write_zeroes_sectors(q, v ? v : UINT_MAX); 797 } 798 799 virtblk_update_capacity(vblk, false); 800 virtio_device_ready(vdev); 801 802 device_add_disk(&vdev->dev, vblk->disk, virtblk_attr_groups); 803 return 0; 804 805 out_free_tags: 806 blk_mq_free_tag_set(&vblk->tag_set); 807 out_put_disk: 808 put_disk(vblk->disk); 809 out_free_vq: 810 vdev->config->del_vqs(vdev); 811 out_free_vblk: 812 kfree(vblk); 813 out_free_index: 814 ida_simple_remove(&vd_index_ida, index); 815 out: 816 return err; 817 } 818 819 static void virtblk_remove(struct virtio_device *vdev) 820 { 821 struct virtio_blk *vblk = vdev->priv; 822 int index = vblk->index; 823 int refc; 824 825 /* Make sure no work handler is accessing the device. */ 826 flush_work(&vblk->config_work); 827 828 del_gendisk(vblk->disk); 829 blk_cleanup_queue(vblk->disk->queue); 830 831 blk_mq_free_tag_set(&vblk->tag_set); 832 833 /* Stop all the virtqueues. */ 834 vdev->config->reset(vdev); 835 836 refc = kref_read(&disk_to_dev(vblk->disk)->kobj.kref); 837 put_disk(vblk->disk); 838 vdev->config->del_vqs(vdev); 839 kfree(vblk->vqs); 840 kfree(vblk); 841 842 /* Only free device id if we don't have any users */ 843 if (refc == 1) 844 ida_simple_remove(&vd_index_ida, index); 845 } 846 847 #ifdef CONFIG_PM_SLEEP 848 static int virtblk_freeze(struct virtio_device *vdev) 849 { 850 struct virtio_blk *vblk = vdev->priv; 851 852 /* Ensure we don't receive any more interrupts */ 853 vdev->config->reset(vdev); 854 855 /* Make sure no work handler is accessing the device. */ 856 flush_work(&vblk->config_work); 857 858 blk_mq_quiesce_queue(vblk->disk->queue); 859 860 vdev->config->del_vqs(vdev); 861 return 0; 862 } 863 864 static int virtblk_restore(struct virtio_device *vdev) 865 { 866 struct virtio_blk *vblk = vdev->priv; 867 int ret; 868 869 ret = init_vq(vdev->priv); 870 if (ret) 871 return ret; 872 873 virtio_device_ready(vdev); 874 875 blk_mq_unquiesce_queue(vblk->disk->queue); 876 return 0; 877 } 878 #endif 879 880 static const struct virtio_device_id id_table[] = { 881 { VIRTIO_ID_BLOCK, VIRTIO_DEV_ANY_ID }, 882 { 0 }, 883 }; 884 885 static unsigned int features_legacy[] = { 886 VIRTIO_BLK_F_SEG_MAX, VIRTIO_BLK_F_SIZE_MAX, VIRTIO_BLK_F_GEOMETRY, 887 VIRTIO_BLK_F_RO, VIRTIO_BLK_F_BLK_SIZE, 888 VIRTIO_BLK_F_FLUSH, VIRTIO_BLK_F_TOPOLOGY, VIRTIO_BLK_F_CONFIG_WCE, 889 VIRTIO_BLK_F_MQ, VIRTIO_BLK_F_DISCARD, VIRTIO_BLK_F_WRITE_ZEROES, 890 } 891 ; 892 static unsigned int features[] = { 893 VIRTIO_BLK_F_SEG_MAX, VIRTIO_BLK_F_SIZE_MAX, VIRTIO_BLK_F_GEOMETRY, 894 VIRTIO_BLK_F_RO, VIRTIO_BLK_F_BLK_SIZE, 895 VIRTIO_BLK_F_FLUSH, VIRTIO_BLK_F_TOPOLOGY, VIRTIO_BLK_F_CONFIG_WCE, 896 VIRTIO_BLK_F_MQ, VIRTIO_BLK_F_DISCARD, VIRTIO_BLK_F_WRITE_ZEROES, 897 }; 898 899 static struct virtio_driver virtio_blk = { 900 .feature_table = features, 901 .feature_table_size = ARRAY_SIZE(features), 902 .feature_table_legacy = features_legacy, 903 .feature_table_size_legacy = ARRAY_SIZE(features_legacy), 904 .driver.name = KBUILD_MODNAME, 905 .driver.owner = THIS_MODULE, 906 .id_table = id_table, 907 .probe = virtblk_probe, 908 .remove = virtblk_remove, 909 .config_changed = virtblk_config_changed, 910 #ifdef CONFIG_PM_SLEEP 911 .freeze = virtblk_freeze, 912 .restore = virtblk_restore, 913 #endif 914 }; 915 916 static int __init init(void) 917 { 918 int error; 919 920 virtblk_wq = alloc_workqueue("virtio-blk", 0, 0); 921 if (!virtblk_wq) 922 return -ENOMEM; 923 924 major = register_blkdev(0, "virtblk"); 925 if (major < 0) { 926 error = major; 927 goto out_destroy_workqueue; 928 } 929 930 error = register_virtio_driver(&virtio_blk); 931 if (error) 932 goto out_unregister_blkdev; 933 return 0; 934 935 out_unregister_blkdev: 936 unregister_blkdev(major, "virtblk"); 937 out_destroy_workqueue: 938 destroy_workqueue(virtblk_wq); 939 return error; 940 } 941 942 static void __exit fini(void) 943 { 944 unregister_virtio_driver(&virtio_blk); 945 unregister_blkdev(major, "virtblk"); 946 destroy_workqueue(virtblk_wq); 947 } 948 module_init(init); 949 module_exit(fini); 950 951 MODULE_DEVICE_TABLE(virtio, id_table); 952 MODULE_DESCRIPTION("Virtio block driver"); 953 MODULE_LICENSE("GPL"); 954