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 blk_mq_stop_hw_queue(hctx); 249 spin_unlock_irqrestore(&vblk->vqs[qid].lock, flags); 250 /* Out of mem doesn't actually happen, since we fall back 251 * to direct descriptors */ 252 if (err == -ENOMEM || err == -ENOSPC) 253 return BLK_STS_DEV_RESOURCE; 254 return BLK_STS_IOERR; 255 } 256 257 if (bd->last && virtqueue_kick_prepare(vblk->vqs[qid].vq)) 258 notify = true; 259 spin_unlock_irqrestore(&vblk->vqs[qid].lock, flags); 260 261 if (notify) 262 virtqueue_notify(vblk->vqs[qid].vq); 263 return BLK_STS_OK; 264 } 265 266 /* return id (s/n) string for *disk to *id_str 267 */ 268 static int virtblk_get_id(struct gendisk *disk, char *id_str) 269 { 270 struct virtio_blk *vblk = disk->private_data; 271 struct request_queue *q = vblk->disk->queue; 272 struct request *req; 273 int err; 274 275 req = blk_get_request(q, REQ_OP_DRV_IN, 0); 276 if (IS_ERR(req)) 277 return PTR_ERR(req); 278 279 err = blk_rq_map_kern(q, req, id_str, VIRTIO_BLK_ID_BYTES, GFP_KERNEL); 280 if (err) 281 goto out; 282 283 blk_execute_rq(vblk->disk->queue, vblk->disk, req, false); 284 err = blk_status_to_errno(virtblk_result(blk_mq_rq_to_pdu(req))); 285 out: 286 blk_put_request(req); 287 return err; 288 } 289 290 /* We provide getgeo only to please some old bootloader/partitioning tools */ 291 static int virtblk_getgeo(struct block_device *bd, struct hd_geometry *geo) 292 { 293 struct virtio_blk *vblk = bd->bd_disk->private_data; 294 295 /* see if the host passed in geometry config */ 296 if (virtio_has_feature(vblk->vdev, VIRTIO_BLK_F_GEOMETRY)) { 297 virtio_cread(vblk->vdev, struct virtio_blk_config, 298 geometry.cylinders, &geo->cylinders); 299 virtio_cread(vblk->vdev, struct virtio_blk_config, 300 geometry.heads, &geo->heads); 301 virtio_cread(vblk->vdev, struct virtio_blk_config, 302 geometry.sectors, &geo->sectors); 303 } else { 304 /* some standard values, similar to sd */ 305 geo->heads = 1 << 6; 306 geo->sectors = 1 << 5; 307 geo->cylinders = get_capacity(bd->bd_disk) >> 11; 308 } 309 return 0; 310 } 311 312 static const struct block_device_operations virtblk_fops = { 313 .owner = THIS_MODULE, 314 .getgeo = virtblk_getgeo, 315 }; 316 317 static int index_to_minor(int index) 318 { 319 return index << PART_BITS; 320 } 321 322 static int minor_to_index(int minor) 323 { 324 return minor >> PART_BITS; 325 } 326 327 static ssize_t serial_show(struct device *dev, 328 struct device_attribute *attr, char *buf) 329 { 330 struct gendisk *disk = dev_to_disk(dev); 331 int err; 332 333 /* sysfs gives us a PAGE_SIZE buffer */ 334 BUILD_BUG_ON(PAGE_SIZE < VIRTIO_BLK_ID_BYTES); 335 336 buf[VIRTIO_BLK_ID_BYTES] = '\0'; 337 err = virtblk_get_id(disk, buf); 338 if (!err) 339 return strlen(buf); 340 341 if (err == -EIO) /* Unsupported? Make it empty. */ 342 return 0; 343 344 return err; 345 } 346 347 static DEVICE_ATTR_RO(serial); 348 349 /* The queue's logical block size must be set before calling this */ 350 static void virtblk_update_capacity(struct virtio_blk *vblk, bool resize) 351 { 352 struct virtio_device *vdev = vblk->vdev; 353 struct request_queue *q = vblk->disk->queue; 354 char cap_str_2[10], cap_str_10[10]; 355 unsigned long long nblocks; 356 u64 capacity; 357 358 /* Host must always specify the capacity. */ 359 virtio_cread(vdev, struct virtio_blk_config, capacity, &capacity); 360 361 /* If capacity is too big, truncate with warning. */ 362 if ((sector_t)capacity != capacity) { 363 dev_warn(&vdev->dev, "Capacity %llu too large: truncating\n", 364 (unsigned long long)capacity); 365 capacity = (sector_t)-1; 366 } 367 368 nblocks = DIV_ROUND_UP_ULL(capacity, queue_logical_block_size(q) >> 9); 369 370 string_get_size(nblocks, queue_logical_block_size(q), 371 STRING_UNITS_2, cap_str_2, sizeof(cap_str_2)); 372 string_get_size(nblocks, queue_logical_block_size(q), 373 STRING_UNITS_10, cap_str_10, sizeof(cap_str_10)); 374 375 dev_notice(&vdev->dev, 376 "[%s] %s%llu %d-byte logical blocks (%s/%s)\n", 377 vblk->disk->disk_name, 378 resize ? "new size: " : "", 379 nblocks, 380 queue_logical_block_size(q), 381 cap_str_10, 382 cap_str_2); 383 384 set_capacity(vblk->disk, capacity); 385 } 386 387 static void virtblk_config_changed_work(struct work_struct *work) 388 { 389 struct virtio_blk *vblk = 390 container_of(work, struct virtio_blk, config_work); 391 char *envp[] = { "RESIZE=1", NULL }; 392 393 virtblk_update_capacity(vblk, true); 394 revalidate_disk(vblk->disk); 395 kobject_uevent_env(&disk_to_dev(vblk->disk)->kobj, KOBJ_CHANGE, envp); 396 } 397 398 static void virtblk_config_changed(struct virtio_device *vdev) 399 { 400 struct virtio_blk *vblk = vdev->priv; 401 402 queue_work(virtblk_wq, &vblk->config_work); 403 } 404 405 static int init_vq(struct virtio_blk *vblk) 406 { 407 int err; 408 int i; 409 vq_callback_t **callbacks; 410 const char **names; 411 struct virtqueue **vqs; 412 unsigned short num_vqs; 413 struct virtio_device *vdev = vblk->vdev; 414 struct irq_affinity desc = { 0, }; 415 416 err = virtio_cread_feature(vdev, VIRTIO_BLK_F_MQ, 417 struct virtio_blk_config, num_queues, 418 &num_vqs); 419 if (err) 420 num_vqs = 1; 421 422 num_vqs = min_t(unsigned int, nr_cpu_ids, num_vqs); 423 424 vblk->vqs = kmalloc_array(num_vqs, sizeof(*vblk->vqs), GFP_KERNEL); 425 if (!vblk->vqs) 426 return -ENOMEM; 427 428 names = kmalloc_array(num_vqs, sizeof(*names), GFP_KERNEL); 429 callbacks = kmalloc_array(num_vqs, sizeof(*callbacks), GFP_KERNEL); 430 vqs = kmalloc_array(num_vqs, sizeof(*vqs), GFP_KERNEL); 431 if (!names || !callbacks || !vqs) { 432 err = -ENOMEM; 433 goto out; 434 } 435 436 for (i = 0; i < num_vqs; i++) { 437 callbacks[i] = virtblk_done; 438 snprintf(vblk->vqs[i].name, VQ_NAME_LEN, "req.%d", i); 439 names[i] = vblk->vqs[i].name; 440 } 441 442 /* Discover virtqueues and write information to configuration. */ 443 err = virtio_find_vqs(vdev, num_vqs, vqs, callbacks, names, &desc); 444 if (err) 445 goto out; 446 447 for (i = 0; i < num_vqs; i++) { 448 spin_lock_init(&vblk->vqs[i].lock); 449 vblk->vqs[i].vq = vqs[i]; 450 } 451 vblk->num_vqs = num_vqs; 452 453 out: 454 kfree(vqs); 455 kfree(callbacks); 456 kfree(names); 457 if (err) 458 kfree(vblk->vqs); 459 return err; 460 } 461 462 /* 463 * Legacy naming scheme used for virtio devices. We are stuck with it for 464 * virtio blk but don't ever use it for any new driver. 465 */ 466 static int virtblk_name_format(char *prefix, int index, char *buf, int buflen) 467 { 468 const int base = 'z' - 'a' + 1; 469 char *begin = buf + strlen(prefix); 470 char *end = buf + buflen; 471 char *p; 472 int unit; 473 474 p = end - 1; 475 *p = '\0'; 476 unit = base; 477 do { 478 if (p == begin) 479 return -EINVAL; 480 *--p = 'a' + (index % unit); 481 index = (index / unit) - 1; 482 } while (index >= 0); 483 484 memmove(begin, p, end - p); 485 memcpy(buf, prefix, strlen(prefix)); 486 487 return 0; 488 } 489 490 static int virtblk_get_cache_mode(struct virtio_device *vdev) 491 { 492 u8 writeback; 493 int err; 494 495 err = virtio_cread_feature(vdev, VIRTIO_BLK_F_CONFIG_WCE, 496 struct virtio_blk_config, wce, 497 &writeback); 498 499 /* 500 * If WCE is not configurable and flush is not available, 501 * assume no writeback cache is in use. 502 */ 503 if (err) 504 writeback = virtio_has_feature(vdev, VIRTIO_BLK_F_FLUSH); 505 506 return writeback; 507 } 508 509 static void virtblk_update_cache_mode(struct virtio_device *vdev) 510 { 511 u8 writeback = virtblk_get_cache_mode(vdev); 512 struct virtio_blk *vblk = vdev->priv; 513 514 blk_queue_write_cache(vblk->disk->queue, writeback, false); 515 revalidate_disk(vblk->disk); 516 } 517 518 static const char *const virtblk_cache_types[] = { 519 "write through", "write back" 520 }; 521 522 static ssize_t 523 cache_type_store(struct device *dev, struct device_attribute *attr, 524 const char *buf, size_t count) 525 { 526 struct gendisk *disk = dev_to_disk(dev); 527 struct virtio_blk *vblk = disk->private_data; 528 struct virtio_device *vdev = vblk->vdev; 529 int i; 530 531 BUG_ON(!virtio_has_feature(vblk->vdev, VIRTIO_BLK_F_CONFIG_WCE)); 532 i = sysfs_match_string(virtblk_cache_types, buf); 533 if (i < 0) 534 return i; 535 536 virtio_cwrite8(vdev, offsetof(struct virtio_blk_config, wce), i); 537 virtblk_update_cache_mode(vdev); 538 return count; 539 } 540 541 static ssize_t 542 cache_type_show(struct device *dev, struct device_attribute *attr, char *buf) 543 { 544 struct gendisk *disk = dev_to_disk(dev); 545 struct virtio_blk *vblk = disk->private_data; 546 u8 writeback = virtblk_get_cache_mode(vblk->vdev); 547 548 BUG_ON(writeback >= ARRAY_SIZE(virtblk_cache_types)); 549 return snprintf(buf, 40, "%s\n", virtblk_cache_types[writeback]); 550 } 551 552 static DEVICE_ATTR_RW(cache_type); 553 554 static struct attribute *virtblk_attrs[] = { 555 &dev_attr_serial.attr, 556 &dev_attr_cache_type.attr, 557 NULL, 558 }; 559 560 static umode_t virtblk_attrs_are_visible(struct kobject *kobj, 561 struct attribute *a, int n) 562 { 563 struct device *dev = container_of(kobj, struct device, kobj); 564 struct gendisk *disk = dev_to_disk(dev); 565 struct virtio_blk *vblk = disk->private_data; 566 struct virtio_device *vdev = vblk->vdev; 567 568 if (a == &dev_attr_cache_type.attr && 569 !virtio_has_feature(vdev, VIRTIO_BLK_F_CONFIG_WCE)) 570 return S_IRUGO; 571 572 return a->mode; 573 } 574 575 static const struct attribute_group virtblk_attr_group = { 576 .attrs = virtblk_attrs, 577 .is_visible = virtblk_attrs_are_visible, 578 }; 579 580 static const struct attribute_group *virtblk_attr_groups[] = { 581 &virtblk_attr_group, 582 NULL, 583 }; 584 585 static int virtblk_init_request(struct blk_mq_tag_set *set, struct request *rq, 586 unsigned int hctx_idx, unsigned int numa_node) 587 { 588 struct virtio_blk *vblk = set->driver_data; 589 struct virtblk_req *vbr = blk_mq_rq_to_pdu(rq); 590 591 sg_init_table(vbr->sg, vblk->sg_elems); 592 return 0; 593 } 594 595 static int virtblk_map_queues(struct blk_mq_tag_set *set) 596 { 597 struct virtio_blk *vblk = set->driver_data; 598 599 return blk_mq_virtio_map_queues(&set->map[HCTX_TYPE_DEFAULT], 600 vblk->vdev, 0); 601 } 602 603 static const struct blk_mq_ops virtio_mq_ops = { 604 .queue_rq = virtio_queue_rq, 605 .commit_rqs = virtio_commit_rqs, 606 .complete = virtblk_request_done, 607 .init_request = virtblk_init_request, 608 .map_queues = virtblk_map_queues, 609 }; 610 611 static unsigned int virtblk_queue_depth; 612 module_param_named(queue_depth, virtblk_queue_depth, uint, 0444); 613 614 static int virtblk_probe(struct virtio_device *vdev) 615 { 616 struct virtio_blk *vblk; 617 struct request_queue *q; 618 int err, index; 619 620 u32 v, blk_size, max_size, sg_elems, opt_io_size; 621 u16 min_io_size; 622 u8 physical_block_exp, alignment_offset; 623 624 if (!vdev->config->get) { 625 dev_err(&vdev->dev, "%s failure: config access disabled\n", 626 __func__); 627 return -EINVAL; 628 } 629 630 err = ida_simple_get(&vd_index_ida, 0, minor_to_index(1 << MINORBITS), 631 GFP_KERNEL); 632 if (err < 0) 633 goto out; 634 index = err; 635 636 /* We need to know how many segments before we allocate. */ 637 err = virtio_cread_feature(vdev, VIRTIO_BLK_F_SEG_MAX, 638 struct virtio_blk_config, seg_max, 639 &sg_elems); 640 641 /* We need at least one SG element, whatever they say. */ 642 if (err || !sg_elems) 643 sg_elems = 1; 644 645 /* We need an extra sg elements at head and tail. */ 646 sg_elems += 2; 647 vdev->priv = vblk = kmalloc(sizeof(*vblk), GFP_KERNEL); 648 if (!vblk) { 649 err = -ENOMEM; 650 goto out_free_index; 651 } 652 653 vblk->vdev = vdev; 654 vblk->sg_elems = sg_elems; 655 656 INIT_WORK(&vblk->config_work, virtblk_config_changed_work); 657 658 err = init_vq(vblk); 659 if (err) 660 goto out_free_vblk; 661 662 /* FIXME: How many partitions? How long is a piece of string? */ 663 vblk->disk = alloc_disk(1 << PART_BITS); 664 if (!vblk->disk) { 665 err = -ENOMEM; 666 goto out_free_vq; 667 } 668 669 /* Default queue sizing is to fill the ring. */ 670 if (!virtblk_queue_depth) { 671 virtblk_queue_depth = vblk->vqs[0].vq->num_free; 672 /* ... but without indirect descs, we use 2 descs per req */ 673 if (!virtio_has_feature(vdev, VIRTIO_RING_F_INDIRECT_DESC)) 674 virtblk_queue_depth /= 2; 675 } 676 677 memset(&vblk->tag_set, 0, sizeof(vblk->tag_set)); 678 vblk->tag_set.ops = &virtio_mq_ops; 679 vblk->tag_set.queue_depth = virtblk_queue_depth; 680 vblk->tag_set.numa_node = NUMA_NO_NODE; 681 vblk->tag_set.flags = BLK_MQ_F_SHOULD_MERGE; 682 vblk->tag_set.cmd_size = 683 sizeof(struct virtblk_req) + 684 sizeof(struct scatterlist) * sg_elems; 685 vblk->tag_set.driver_data = vblk; 686 vblk->tag_set.nr_hw_queues = vblk->num_vqs; 687 688 err = blk_mq_alloc_tag_set(&vblk->tag_set); 689 if (err) 690 goto out_put_disk; 691 692 q = blk_mq_init_queue(&vblk->tag_set); 693 if (IS_ERR(q)) { 694 err = -ENOMEM; 695 goto out_free_tags; 696 } 697 vblk->disk->queue = q; 698 699 q->queuedata = vblk; 700 701 virtblk_name_format("vd", index, vblk->disk->disk_name, DISK_NAME_LEN); 702 703 vblk->disk->major = major; 704 vblk->disk->first_minor = index_to_minor(index); 705 vblk->disk->private_data = vblk; 706 vblk->disk->fops = &virtblk_fops; 707 vblk->disk->flags |= GENHD_FL_EXT_DEVT; 708 vblk->index = index; 709 710 /* configure queue flush support */ 711 virtblk_update_cache_mode(vdev); 712 713 /* If disk is read-only in the host, the guest should obey */ 714 if (virtio_has_feature(vdev, VIRTIO_BLK_F_RO)) 715 set_disk_ro(vblk->disk, 1); 716 717 /* We can handle whatever the host told us to handle. */ 718 blk_queue_max_segments(q, vblk->sg_elems-2); 719 720 /* No real sector limit. */ 721 blk_queue_max_hw_sectors(q, -1U); 722 723 max_size = virtio_max_dma_size(vdev); 724 725 /* Host can optionally specify maximum segment size and number of 726 * segments. */ 727 err = virtio_cread_feature(vdev, VIRTIO_BLK_F_SIZE_MAX, 728 struct virtio_blk_config, size_max, &v); 729 if (!err) 730 max_size = min(max_size, v); 731 732 blk_queue_max_segment_size(q, max_size); 733 734 /* Host can optionally specify the block size of the device */ 735 err = virtio_cread_feature(vdev, VIRTIO_BLK_F_BLK_SIZE, 736 struct virtio_blk_config, blk_size, 737 &blk_size); 738 if (!err) 739 blk_queue_logical_block_size(q, blk_size); 740 else 741 blk_size = queue_logical_block_size(q); 742 743 /* Use topology information if available */ 744 err = virtio_cread_feature(vdev, VIRTIO_BLK_F_TOPOLOGY, 745 struct virtio_blk_config, physical_block_exp, 746 &physical_block_exp); 747 if (!err && physical_block_exp) 748 blk_queue_physical_block_size(q, 749 blk_size * (1 << physical_block_exp)); 750 751 err = virtio_cread_feature(vdev, VIRTIO_BLK_F_TOPOLOGY, 752 struct virtio_blk_config, alignment_offset, 753 &alignment_offset); 754 if (!err && alignment_offset) 755 blk_queue_alignment_offset(q, blk_size * alignment_offset); 756 757 err = virtio_cread_feature(vdev, VIRTIO_BLK_F_TOPOLOGY, 758 struct virtio_blk_config, min_io_size, 759 &min_io_size); 760 if (!err && min_io_size) 761 blk_queue_io_min(q, blk_size * min_io_size); 762 763 err = virtio_cread_feature(vdev, VIRTIO_BLK_F_TOPOLOGY, 764 struct virtio_blk_config, opt_io_size, 765 &opt_io_size); 766 if (!err && opt_io_size) 767 blk_queue_io_opt(q, blk_size * opt_io_size); 768 769 if (virtio_has_feature(vdev, VIRTIO_BLK_F_DISCARD)) { 770 q->limits.discard_granularity = blk_size; 771 772 virtio_cread(vdev, struct virtio_blk_config, 773 discard_sector_alignment, &v); 774 q->limits.discard_alignment = v ? v << SECTOR_SHIFT : 0; 775 776 virtio_cread(vdev, struct virtio_blk_config, 777 max_discard_sectors, &v); 778 blk_queue_max_discard_sectors(q, v ? v : UINT_MAX); 779 780 virtio_cread(vdev, struct virtio_blk_config, max_discard_seg, 781 &v); 782 blk_queue_max_discard_segments(q, 783 min_not_zero(v, 784 MAX_DISCARD_SEGMENTS)); 785 786 blk_queue_flag_set(QUEUE_FLAG_DISCARD, q); 787 } 788 789 if (virtio_has_feature(vdev, VIRTIO_BLK_F_WRITE_ZEROES)) { 790 virtio_cread(vdev, struct virtio_blk_config, 791 max_write_zeroes_sectors, &v); 792 blk_queue_max_write_zeroes_sectors(q, v ? v : UINT_MAX); 793 } 794 795 virtblk_update_capacity(vblk, false); 796 virtio_device_ready(vdev); 797 798 device_add_disk(&vdev->dev, vblk->disk, virtblk_attr_groups); 799 return 0; 800 801 out_free_tags: 802 blk_mq_free_tag_set(&vblk->tag_set); 803 out_put_disk: 804 put_disk(vblk->disk); 805 out_free_vq: 806 vdev->config->del_vqs(vdev); 807 out_free_vblk: 808 kfree(vblk); 809 out_free_index: 810 ida_simple_remove(&vd_index_ida, index); 811 out: 812 return err; 813 } 814 815 static void virtblk_remove(struct virtio_device *vdev) 816 { 817 struct virtio_blk *vblk = vdev->priv; 818 int index = vblk->index; 819 int refc; 820 821 /* Make sure no work handler is accessing the device. */ 822 flush_work(&vblk->config_work); 823 824 del_gendisk(vblk->disk); 825 blk_cleanup_queue(vblk->disk->queue); 826 827 blk_mq_free_tag_set(&vblk->tag_set); 828 829 /* Stop all the virtqueues. */ 830 vdev->config->reset(vdev); 831 832 refc = kref_read(&disk_to_dev(vblk->disk)->kobj.kref); 833 put_disk(vblk->disk); 834 vdev->config->del_vqs(vdev); 835 kfree(vblk->vqs); 836 kfree(vblk); 837 838 /* Only free device id if we don't have any users */ 839 if (refc == 1) 840 ida_simple_remove(&vd_index_ida, index); 841 } 842 843 #ifdef CONFIG_PM_SLEEP 844 static int virtblk_freeze(struct virtio_device *vdev) 845 { 846 struct virtio_blk *vblk = vdev->priv; 847 848 /* Ensure we don't receive any more interrupts */ 849 vdev->config->reset(vdev); 850 851 /* Make sure no work handler is accessing the device. */ 852 flush_work(&vblk->config_work); 853 854 blk_mq_quiesce_queue(vblk->disk->queue); 855 856 vdev->config->del_vqs(vdev); 857 return 0; 858 } 859 860 static int virtblk_restore(struct virtio_device *vdev) 861 { 862 struct virtio_blk *vblk = vdev->priv; 863 int ret; 864 865 ret = init_vq(vdev->priv); 866 if (ret) 867 return ret; 868 869 virtio_device_ready(vdev); 870 871 blk_mq_unquiesce_queue(vblk->disk->queue); 872 return 0; 873 } 874 #endif 875 876 static const struct virtio_device_id id_table[] = { 877 { VIRTIO_ID_BLOCK, VIRTIO_DEV_ANY_ID }, 878 { 0 }, 879 }; 880 881 static unsigned int features_legacy[] = { 882 VIRTIO_BLK_F_SEG_MAX, VIRTIO_BLK_F_SIZE_MAX, VIRTIO_BLK_F_GEOMETRY, 883 VIRTIO_BLK_F_RO, VIRTIO_BLK_F_BLK_SIZE, 884 VIRTIO_BLK_F_FLUSH, VIRTIO_BLK_F_TOPOLOGY, VIRTIO_BLK_F_CONFIG_WCE, 885 VIRTIO_BLK_F_MQ, VIRTIO_BLK_F_DISCARD, VIRTIO_BLK_F_WRITE_ZEROES, 886 } 887 ; 888 static unsigned int features[] = { 889 VIRTIO_BLK_F_SEG_MAX, VIRTIO_BLK_F_SIZE_MAX, VIRTIO_BLK_F_GEOMETRY, 890 VIRTIO_BLK_F_RO, VIRTIO_BLK_F_BLK_SIZE, 891 VIRTIO_BLK_F_FLUSH, VIRTIO_BLK_F_TOPOLOGY, VIRTIO_BLK_F_CONFIG_WCE, 892 VIRTIO_BLK_F_MQ, VIRTIO_BLK_F_DISCARD, VIRTIO_BLK_F_WRITE_ZEROES, 893 }; 894 895 static struct virtio_driver virtio_blk = { 896 .feature_table = features, 897 .feature_table_size = ARRAY_SIZE(features), 898 .feature_table_legacy = features_legacy, 899 .feature_table_size_legacy = ARRAY_SIZE(features_legacy), 900 .driver.name = KBUILD_MODNAME, 901 .driver.owner = THIS_MODULE, 902 .id_table = id_table, 903 .probe = virtblk_probe, 904 .remove = virtblk_remove, 905 .config_changed = virtblk_config_changed, 906 #ifdef CONFIG_PM_SLEEP 907 .freeze = virtblk_freeze, 908 .restore = virtblk_restore, 909 #endif 910 }; 911 912 static int __init init(void) 913 { 914 int error; 915 916 virtblk_wq = alloc_workqueue("virtio-blk", 0, 0); 917 if (!virtblk_wq) 918 return -ENOMEM; 919 920 major = register_blkdev(0, "virtblk"); 921 if (major < 0) { 922 error = major; 923 goto out_destroy_workqueue; 924 } 925 926 error = register_virtio_driver(&virtio_blk); 927 if (error) 928 goto out_unregister_blkdev; 929 return 0; 930 931 out_unregister_blkdev: 932 unregister_blkdev(major, "virtblk"); 933 out_destroy_workqueue: 934 destroy_workqueue(virtblk_wq); 935 return error; 936 } 937 938 static void __exit fini(void) 939 { 940 unregister_virtio_driver(&virtio_blk); 941 unregister_blkdev(major, "virtblk"); 942 destroy_workqueue(virtblk_wq); 943 } 944 module_init(init); 945 module_exit(fini); 946 947 MODULE_DEVICE_TABLE(virtio, id_table); 948 MODULE_DESCRIPTION("Virtio block driver"); 949 MODULE_LICENSE("GPL"); 950