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