1 //#define DEBUG 2 #include <linux/spinlock.h> 3 #include <linux/slab.h> 4 #include <linux/blkdev.h> 5 #include <linux/hdreg.h> 6 #include <linux/module.h> 7 #include <linux/mutex.h> 8 #include <linux/virtio.h> 9 #include <linux/virtio_blk.h> 10 #include <linux/scatterlist.h> 11 #include <linux/string_helpers.h> 12 #include <scsi/scsi_cmnd.h> 13 #include <linux/idr.h> 14 #include <linux/blk-mq.h> 15 #include <linux/numa.h> 16 17 #define PART_BITS 4 18 19 static int major; 20 static DEFINE_IDA(vd_index_ida); 21 22 static struct workqueue_struct *virtblk_wq; 23 24 struct virtio_blk 25 { 26 struct virtio_device *vdev; 27 struct virtqueue *vq; 28 spinlock_t vq_lock; 29 30 /* The disk structure for the kernel. */ 31 struct gendisk *disk; 32 33 /* Block layer tags. */ 34 struct blk_mq_tag_set tag_set; 35 36 /* Process context for config space updates */ 37 struct work_struct config_work; 38 39 /* Lock for config space updates */ 40 struct mutex config_lock; 41 42 /* enable config space updates */ 43 bool config_enable; 44 45 /* What host tells us, plus 2 for header & tailer. */ 46 unsigned int sg_elems; 47 48 /* Ida index - used to track minor number allocations. */ 49 int index; 50 }; 51 52 struct virtblk_req 53 { 54 struct request *req; 55 struct virtio_blk_outhdr out_hdr; 56 struct virtio_scsi_inhdr in_hdr; 57 u8 status; 58 struct scatterlist sg[]; 59 }; 60 61 static inline int virtblk_result(struct virtblk_req *vbr) 62 { 63 switch (vbr->status) { 64 case VIRTIO_BLK_S_OK: 65 return 0; 66 case VIRTIO_BLK_S_UNSUPP: 67 return -ENOTTY; 68 default: 69 return -EIO; 70 } 71 } 72 73 static int __virtblk_add_req(struct virtqueue *vq, 74 struct virtblk_req *vbr, 75 struct scatterlist *data_sg, 76 bool have_data) 77 { 78 struct scatterlist hdr, status, cmd, sense, inhdr, *sgs[6]; 79 unsigned int num_out = 0, num_in = 0; 80 int type = vbr->out_hdr.type & ~VIRTIO_BLK_T_OUT; 81 82 sg_init_one(&hdr, &vbr->out_hdr, sizeof(vbr->out_hdr)); 83 sgs[num_out++] = &hdr; 84 85 /* 86 * If this is a packet command we need a couple of additional headers. 87 * Behind the normal outhdr we put a segment with the scsi command 88 * block, and before the normal inhdr we put the sense data and the 89 * inhdr with additional status information. 90 */ 91 if (type == VIRTIO_BLK_T_SCSI_CMD) { 92 sg_init_one(&cmd, vbr->req->cmd, vbr->req->cmd_len); 93 sgs[num_out++] = &cmd; 94 } 95 96 if (have_data) { 97 if (vbr->out_hdr.type & VIRTIO_BLK_T_OUT) 98 sgs[num_out++] = data_sg; 99 else 100 sgs[num_out + num_in++] = data_sg; 101 } 102 103 if (type == VIRTIO_BLK_T_SCSI_CMD) { 104 sg_init_one(&sense, vbr->req->sense, SCSI_SENSE_BUFFERSIZE); 105 sgs[num_out + num_in++] = &sense; 106 sg_init_one(&inhdr, &vbr->in_hdr, sizeof(vbr->in_hdr)); 107 sgs[num_out + num_in++] = &inhdr; 108 } 109 110 sg_init_one(&status, &vbr->status, sizeof(vbr->status)); 111 sgs[num_out + num_in++] = &status; 112 113 return virtqueue_add_sgs(vq, sgs, num_out, num_in, vbr, GFP_ATOMIC); 114 } 115 116 static inline void virtblk_request_done(struct request *req) 117 { 118 struct virtblk_req *vbr = blk_mq_rq_to_pdu(req); 119 int error = virtblk_result(vbr); 120 121 if (req->cmd_type == REQ_TYPE_BLOCK_PC) { 122 req->resid_len = vbr->in_hdr.residual; 123 req->sense_len = vbr->in_hdr.sense_len; 124 req->errors = vbr->in_hdr.errors; 125 } else if (req->cmd_type == REQ_TYPE_SPECIAL) { 126 req->errors = (error != 0); 127 } 128 129 blk_mq_end_io(req, error); 130 } 131 132 static void virtblk_done(struct virtqueue *vq) 133 { 134 struct virtio_blk *vblk = vq->vdev->priv; 135 bool req_done = false; 136 struct virtblk_req *vbr; 137 unsigned long flags; 138 unsigned int len; 139 140 spin_lock_irqsave(&vblk->vq_lock, flags); 141 do { 142 virtqueue_disable_cb(vq); 143 while ((vbr = virtqueue_get_buf(vblk->vq, &len)) != NULL) { 144 blk_mq_complete_request(vbr->req); 145 req_done = true; 146 } 147 if (unlikely(virtqueue_is_broken(vq))) 148 break; 149 } while (!virtqueue_enable_cb(vq)); 150 151 /* In case queue is stopped waiting for more buffers. */ 152 if (req_done) 153 blk_mq_start_stopped_hw_queues(vblk->disk->queue, true); 154 spin_unlock_irqrestore(&vblk->vq_lock, flags); 155 } 156 157 static int virtio_queue_rq(struct blk_mq_hw_ctx *hctx, struct request *req) 158 { 159 struct virtio_blk *vblk = hctx->queue->queuedata; 160 struct virtblk_req *vbr = blk_mq_rq_to_pdu(req); 161 unsigned long flags; 162 unsigned int num; 163 const bool last = (req->cmd_flags & REQ_END) != 0; 164 int err; 165 bool notify = false; 166 167 BUG_ON(req->nr_phys_segments + 2 > vblk->sg_elems); 168 169 vbr->req = req; 170 if (req->cmd_flags & REQ_FLUSH) { 171 vbr->out_hdr.type = VIRTIO_BLK_T_FLUSH; 172 vbr->out_hdr.sector = 0; 173 vbr->out_hdr.ioprio = req_get_ioprio(vbr->req); 174 } else { 175 switch (req->cmd_type) { 176 case REQ_TYPE_FS: 177 vbr->out_hdr.type = 0; 178 vbr->out_hdr.sector = blk_rq_pos(vbr->req); 179 vbr->out_hdr.ioprio = req_get_ioprio(vbr->req); 180 break; 181 case REQ_TYPE_BLOCK_PC: 182 vbr->out_hdr.type = VIRTIO_BLK_T_SCSI_CMD; 183 vbr->out_hdr.sector = 0; 184 vbr->out_hdr.ioprio = req_get_ioprio(vbr->req); 185 break; 186 case REQ_TYPE_SPECIAL: 187 vbr->out_hdr.type = VIRTIO_BLK_T_GET_ID; 188 vbr->out_hdr.sector = 0; 189 vbr->out_hdr.ioprio = req_get_ioprio(vbr->req); 190 break; 191 default: 192 /* We don't put anything else in the queue. */ 193 BUG(); 194 } 195 } 196 197 num = blk_rq_map_sg(hctx->queue, vbr->req, vbr->sg); 198 if (num) { 199 if (rq_data_dir(vbr->req) == WRITE) 200 vbr->out_hdr.type |= VIRTIO_BLK_T_OUT; 201 else 202 vbr->out_hdr.type |= VIRTIO_BLK_T_IN; 203 } 204 205 spin_lock_irqsave(&vblk->vq_lock, flags); 206 err = __virtblk_add_req(vblk->vq, vbr, vbr->sg, num); 207 if (err) { 208 virtqueue_kick(vblk->vq); 209 blk_mq_stop_hw_queue(hctx); 210 spin_unlock_irqrestore(&vblk->vq_lock, flags); 211 /* Out of mem doesn't actually happen, since we fall back 212 * to direct descriptors */ 213 if (err == -ENOMEM || err == -ENOSPC) 214 return BLK_MQ_RQ_QUEUE_BUSY; 215 return BLK_MQ_RQ_QUEUE_ERROR; 216 } 217 218 if (last && virtqueue_kick_prepare(vblk->vq)) 219 notify = true; 220 spin_unlock_irqrestore(&vblk->vq_lock, flags); 221 222 if (notify) 223 virtqueue_notify(vblk->vq); 224 return BLK_MQ_RQ_QUEUE_OK; 225 } 226 227 /* return id (s/n) string for *disk to *id_str 228 */ 229 static int virtblk_get_id(struct gendisk *disk, char *id_str) 230 { 231 struct virtio_blk *vblk = disk->private_data; 232 struct request *req; 233 struct bio *bio; 234 int err; 235 236 bio = bio_map_kern(vblk->disk->queue, id_str, VIRTIO_BLK_ID_BYTES, 237 GFP_KERNEL); 238 if (IS_ERR(bio)) 239 return PTR_ERR(bio); 240 241 req = blk_make_request(vblk->disk->queue, bio, GFP_KERNEL); 242 if (IS_ERR(req)) { 243 bio_put(bio); 244 return PTR_ERR(req); 245 } 246 247 req->cmd_type = REQ_TYPE_SPECIAL; 248 err = blk_execute_rq(vblk->disk->queue, vblk->disk, req, false); 249 blk_put_request(req); 250 251 return err; 252 } 253 254 static int virtblk_ioctl(struct block_device *bdev, fmode_t mode, 255 unsigned int cmd, unsigned long data) 256 { 257 struct gendisk *disk = bdev->bd_disk; 258 struct virtio_blk *vblk = disk->private_data; 259 260 /* 261 * Only allow the generic SCSI ioctls if the host can support it. 262 */ 263 if (!virtio_has_feature(vblk->vdev, VIRTIO_BLK_F_SCSI)) 264 return -ENOTTY; 265 266 return scsi_cmd_blk_ioctl(bdev, mode, cmd, 267 (void __user *)data); 268 } 269 270 /* We provide getgeo only to please some old bootloader/partitioning tools */ 271 static int virtblk_getgeo(struct block_device *bd, struct hd_geometry *geo) 272 { 273 struct virtio_blk *vblk = bd->bd_disk->private_data; 274 275 /* see if the host passed in geometry config */ 276 if (virtio_has_feature(vblk->vdev, VIRTIO_BLK_F_GEOMETRY)) { 277 virtio_cread(vblk->vdev, struct virtio_blk_config, 278 geometry.cylinders, &geo->cylinders); 279 virtio_cread(vblk->vdev, struct virtio_blk_config, 280 geometry.heads, &geo->heads); 281 virtio_cread(vblk->vdev, struct virtio_blk_config, 282 geometry.sectors, &geo->sectors); 283 } else { 284 /* some standard values, similar to sd */ 285 geo->heads = 1 << 6; 286 geo->sectors = 1 << 5; 287 geo->cylinders = get_capacity(bd->bd_disk) >> 11; 288 } 289 return 0; 290 } 291 292 static const struct block_device_operations virtblk_fops = { 293 .ioctl = virtblk_ioctl, 294 .owner = THIS_MODULE, 295 .getgeo = virtblk_getgeo, 296 }; 297 298 static int index_to_minor(int index) 299 { 300 return index << PART_BITS; 301 } 302 303 static int minor_to_index(int minor) 304 { 305 return minor >> PART_BITS; 306 } 307 308 static ssize_t virtblk_serial_show(struct device *dev, 309 struct device_attribute *attr, char *buf) 310 { 311 struct gendisk *disk = dev_to_disk(dev); 312 int err; 313 314 /* sysfs gives us a PAGE_SIZE buffer */ 315 BUILD_BUG_ON(PAGE_SIZE < VIRTIO_BLK_ID_BYTES); 316 317 buf[VIRTIO_BLK_ID_BYTES] = '\0'; 318 err = virtblk_get_id(disk, buf); 319 if (!err) 320 return strlen(buf); 321 322 if (err == -EIO) /* Unsupported? Make it empty. */ 323 return 0; 324 325 return err; 326 } 327 DEVICE_ATTR(serial, S_IRUGO, virtblk_serial_show, NULL); 328 329 static void virtblk_config_changed_work(struct work_struct *work) 330 { 331 struct virtio_blk *vblk = 332 container_of(work, struct virtio_blk, config_work); 333 struct virtio_device *vdev = vblk->vdev; 334 struct request_queue *q = vblk->disk->queue; 335 char cap_str_2[10], cap_str_10[10]; 336 char *envp[] = { "RESIZE=1", NULL }; 337 u64 capacity, size; 338 339 mutex_lock(&vblk->config_lock); 340 if (!vblk->config_enable) 341 goto done; 342 343 /* Host must always specify the capacity. */ 344 virtio_cread(vdev, struct virtio_blk_config, capacity, &capacity); 345 346 /* If capacity is too big, truncate with warning. */ 347 if ((sector_t)capacity != capacity) { 348 dev_warn(&vdev->dev, "Capacity %llu too large: truncating\n", 349 (unsigned long long)capacity); 350 capacity = (sector_t)-1; 351 } 352 353 size = capacity * queue_logical_block_size(q); 354 string_get_size(size, STRING_UNITS_2, cap_str_2, sizeof(cap_str_2)); 355 string_get_size(size, STRING_UNITS_10, cap_str_10, sizeof(cap_str_10)); 356 357 dev_notice(&vdev->dev, 358 "new size: %llu %d-byte logical blocks (%s/%s)\n", 359 (unsigned long long)capacity, 360 queue_logical_block_size(q), 361 cap_str_10, cap_str_2); 362 363 set_capacity(vblk->disk, capacity); 364 revalidate_disk(vblk->disk); 365 kobject_uevent_env(&disk_to_dev(vblk->disk)->kobj, KOBJ_CHANGE, envp); 366 done: 367 mutex_unlock(&vblk->config_lock); 368 } 369 370 static void virtblk_config_changed(struct virtio_device *vdev) 371 { 372 struct virtio_blk *vblk = vdev->priv; 373 374 queue_work(virtblk_wq, &vblk->config_work); 375 } 376 377 static int init_vq(struct virtio_blk *vblk) 378 { 379 int err = 0; 380 381 /* We expect one virtqueue, for output. */ 382 vblk->vq = virtio_find_single_vq(vblk->vdev, virtblk_done, "requests"); 383 if (IS_ERR(vblk->vq)) 384 err = PTR_ERR(vblk->vq); 385 386 return err; 387 } 388 389 /* 390 * Legacy naming scheme used for virtio devices. We are stuck with it for 391 * virtio blk but don't ever use it for any new driver. 392 */ 393 static int virtblk_name_format(char *prefix, int index, char *buf, int buflen) 394 { 395 const int base = 'z' - 'a' + 1; 396 char *begin = buf + strlen(prefix); 397 char *end = buf + buflen; 398 char *p; 399 int unit; 400 401 p = end - 1; 402 *p = '\0'; 403 unit = base; 404 do { 405 if (p == begin) 406 return -EINVAL; 407 *--p = 'a' + (index % unit); 408 index = (index / unit) - 1; 409 } while (index >= 0); 410 411 memmove(begin, p, end - p); 412 memcpy(buf, prefix, strlen(prefix)); 413 414 return 0; 415 } 416 417 static int virtblk_get_cache_mode(struct virtio_device *vdev) 418 { 419 u8 writeback; 420 int err; 421 422 err = virtio_cread_feature(vdev, VIRTIO_BLK_F_CONFIG_WCE, 423 struct virtio_blk_config, wce, 424 &writeback); 425 if (err) 426 writeback = virtio_has_feature(vdev, VIRTIO_BLK_F_WCE); 427 428 return writeback; 429 } 430 431 static void virtblk_update_cache_mode(struct virtio_device *vdev) 432 { 433 u8 writeback = virtblk_get_cache_mode(vdev); 434 struct virtio_blk *vblk = vdev->priv; 435 436 if (writeback) 437 blk_queue_flush(vblk->disk->queue, REQ_FLUSH); 438 else 439 blk_queue_flush(vblk->disk->queue, 0); 440 441 revalidate_disk(vblk->disk); 442 } 443 444 static const char *const virtblk_cache_types[] = { 445 "write through", "write back" 446 }; 447 448 static ssize_t 449 virtblk_cache_type_store(struct device *dev, struct device_attribute *attr, 450 const char *buf, size_t count) 451 { 452 struct gendisk *disk = dev_to_disk(dev); 453 struct virtio_blk *vblk = disk->private_data; 454 struct virtio_device *vdev = vblk->vdev; 455 int i; 456 457 BUG_ON(!virtio_has_feature(vblk->vdev, VIRTIO_BLK_F_CONFIG_WCE)); 458 for (i = ARRAY_SIZE(virtblk_cache_types); --i >= 0; ) 459 if (sysfs_streq(buf, virtblk_cache_types[i])) 460 break; 461 462 if (i < 0) 463 return -EINVAL; 464 465 virtio_cwrite8(vdev, offsetof(struct virtio_blk_config, wce), i); 466 virtblk_update_cache_mode(vdev); 467 return count; 468 } 469 470 static ssize_t 471 virtblk_cache_type_show(struct device *dev, struct device_attribute *attr, 472 char *buf) 473 { 474 struct gendisk *disk = dev_to_disk(dev); 475 struct virtio_blk *vblk = disk->private_data; 476 u8 writeback = virtblk_get_cache_mode(vblk->vdev); 477 478 BUG_ON(writeback >= ARRAY_SIZE(virtblk_cache_types)); 479 return snprintf(buf, 40, "%s\n", virtblk_cache_types[writeback]); 480 } 481 482 static const struct device_attribute dev_attr_cache_type_ro = 483 __ATTR(cache_type, S_IRUGO, 484 virtblk_cache_type_show, NULL); 485 static const struct device_attribute dev_attr_cache_type_rw = 486 __ATTR(cache_type, S_IRUGO|S_IWUSR, 487 virtblk_cache_type_show, virtblk_cache_type_store); 488 489 static int virtblk_init_request(void *data, struct request *rq, 490 unsigned int hctx_idx, unsigned int request_idx, 491 unsigned int numa_node) 492 { 493 struct virtio_blk *vblk = data; 494 struct virtblk_req *vbr = blk_mq_rq_to_pdu(rq); 495 496 sg_init_table(vbr->sg, vblk->sg_elems); 497 return 0; 498 } 499 500 static struct blk_mq_ops virtio_mq_ops = { 501 .queue_rq = virtio_queue_rq, 502 .map_queue = blk_mq_map_queue, 503 .complete = virtblk_request_done, 504 .init_request = virtblk_init_request, 505 }; 506 507 static unsigned int virtblk_queue_depth; 508 module_param_named(queue_depth, virtblk_queue_depth, uint, 0444); 509 510 static int virtblk_probe(struct virtio_device *vdev) 511 { 512 struct virtio_blk *vblk; 513 struct request_queue *q; 514 int err, index; 515 516 u64 cap; 517 u32 v, blk_size, sg_elems, opt_io_size; 518 u16 min_io_size; 519 u8 physical_block_exp, alignment_offset; 520 521 err = ida_simple_get(&vd_index_ida, 0, minor_to_index(1 << MINORBITS), 522 GFP_KERNEL); 523 if (err < 0) 524 goto out; 525 index = err; 526 527 /* We need to know how many segments before we allocate. */ 528 err = virtio_cread_feature(vdev, VIRTIO_BLK_F_SEG_MAX, 529 struct virtio_blk_config, seg_max, 530 &sg_elems); 531 532 /* We need at least one SG element, whatever they say. */ 533 if (err || !sg_elems) 534 sg_elems = 1; 535 536 /* We need an extra sg elements at head and tail. */ 537 sg_elems += 2; 538 vdev->priv = vblk = kmalloc(sizeof(*vblk), GFP_KERNEL); 539 if (!vblk) { 540 err = -ENOMEM; 541 goto out_free_index; 542 } 543 544 vblk->vdev = vdev; 545 vblk->sg_elems = sg_elems; 546 mutex_init(&vblk->config_lock); 547 548 INIT_WORK(&vblk->config_work, virtblk_config_changed_work); 549 vblk->config_enable = true; 550 551 err = init_vq(vblk); 552 if (err) 553 goto out_free_vblk; 554 spin_lock_init(&vblk->vq_lock); 555 556 /* FIXME: How many partitions? How long is a piece of string? */ 557 vblk->disk = alloc_disk(1 << PART_BITS); 558 if (!vblk->disk) { 559 err = -ENOMEM; 560 goto out_free_vq; 561 } 562 563 /* Default queue sizing is to fill the ring. */ 564 if (!virtblk_queue_depth) { 565 virtblk_queue_depth = vblk->vq->num_free; 566 /* ... but without indirect descs, we use 2 descs per req */ 567 if (!virtio_has_feature(vdev, VIRTIO_RING_F_INDIRECT_DESC)) 568 virtblk_queue_depth /= 2; 569 } 570 571 memset(&vblk->tag_set, 0, sizeof(vblk->tag_set)); 572 vblk->tag_set.ops = &virtio_mq_ops; 573 vblk->tag_set.nr_hw_queues = 1; 574 vblk->tag_set.queue_depth = virtblk_queue_depth; 575 vblk->tag_set.numa_node = NUMA_NO_NODE; 576 vblk->tag_set.flags = BLK_MQ_F_SHOULD_MERGE; 577 vblk->tag_set.cmd_size = 578 sizeof(struct virtblk_req) + 579 sizeof(struct scatterlist) * sg_elems; 580 vblk->tag_set.driver_data = vblk; 581 582 err = blk_mq_alloc_tag_set(&vblk->tag_set); 583 if (err) 584 goto out_put_disk; 585 586 q = vblk->disk->queue = blk_mq_init_queue(&vblk->tag_set); 587 if (!q) { 588 err = -ENOMEM; 589 goto out_free_tags; 590 } 591 592 q->queuedata = vblk; 593 594 virtblk_name_format("vd", index, vblk->disk->disk_name, DISK_NAME_LEN); 595 596 vblk->disk->major = major; 597 vblk->disk->first_minor = index_to_minor(index); 598 vblk->disk->private_data = vblk; 599 vblk->disk->fops = &virtblk_fops; 600 vblk->disk->driverfs_dev = &vdev->dev; 601 vblk->index = index; 602 603 /* configure queue flush support */ 604 virtblk_update_cache_mode(vdev); 605 606 /* If disk is read-only in the host, the guest should obey */ 607 if (virtio_has_feature(vdev, VIRTIO_BLK_F_RO)) 608 set_disk_ro(vblk->disk, 1); 609 610 /* Host must always specify the capacity. */ 611 virtio_cread(vdev, struct virtio_blk_config, capacity, &cap); 612 613 /* If capacity is too big, truncate with warning. */ 614 if ((sector_t)cap != cap) { 615 dev_warn(&vdev->dev, "Capacity %llu too large: truncating\n", 616 (unsigned long long)cap); 617 cap = (sector_t)-1; 618 } 619 set_capacity(vblk->disk, cap); 620 621 /* We can handle whatever the host told us to handle. */ 622 blk_queue_max_segments(q, vblk->sg_elems-2); 623 624 /* No need to bounce any requests */ 625 blk_queue_bounce_limit(q, BLK_BOUNCE_ANY); 626 627 /* No real sector limit. */ 628 blk_queue_max_hw_sectors(q, -1U); 629 630 /* Host can optionally specify maximum segment size and number of 631 * segments. */ 632 err = virtio_cread_feature(vdev, VIRTIO_BLK_F_SIZE_MAX, 633 struct virtio_blk_config, size_max, &v); 634 if (!err) 635 blk_queue_max_segment_size(q, v); 636 else 637 blk_queue_max_segment_size(q, -1U); 638 639 /* Host can optionally specify the block size of the device */ 640 err = virtio_cread_feature(vdev, VIRTIO_BLK_F_BLK_SIZE, 641 struct virtio_blk_config, blk_size, 642 &blk_size); 643 if (!err) 644 blk_queue_logical_block_size(q, blk_size); 645 else 646 blk_size = queue_logical_block_size(q); 647 648 /* Use topology information if available */ 649 err = virtio_cread_feature(vdev, VIRTIO_BLK_F_TOPOLOGY, 650 struct virtio_blk_config, physical_block_exp, 651 &physical_block_exp); 652 if (!err && physical_block_exp) 653 blk_queue_physical_block_size(q, 654 blk_size * (1 << physical_block_exp)); 655 656 err = virtio_cread_feature(vdev, VIRTIO_BLK_F_TOPOLOGY, 657 struct virtio_blk_config, alignment_offset, 658 &alignment_offset); 659 if (!err && alignment_offset) 660 blk_queue_alignment_offset(q, blk_size * alignment_offset); 661 662 err = virtio_cread_feature(vdev, VIRTIO_BLK_F_TOPOLOGY, 663 struct virtio_blk_config, min_io_size, 664 &min_io_size); 665 if (!err && min_io_size) 666 blk_queue_io_min(q, blk_size * min_io_size); 667 668 err = virtio_cread_feature(vdev, VIRTIO_BLK_F_TOPOLOGY, 669 struct virtio_blk_config, opt_io_size, 670 &opt_io_size); 671 if (!err && opt_io_size) 672 blk_queue_io_opt(q, blk_size * opt_io_size); 673 674 add_disk(vblk->disk); 675 err = device_create_file(disk_to_dev(vblk->disk), &dev_attr_serial); 676 if (err) 677 goto out_del_disk; 678 679 if (virtio_has_feature(vdev, VIRTIO_BLK_F_CONFIG_WCE)) 680 err = device_create_file(disk_to_dev(vblk->disk), 681 &dev_attr_cache_type_rw); 682 else 683 err = device_create_file(disk_to_dev(vblk->disk), 684 &dev_attr_cache_type_ro); 685 if (err) 686 goto out_del_disk; 687 return 0; 688 689 out_del_disk: 690 del_gendisk(vblk->disk); 691 blk_cleanup_queue(vblk->disk->queue); 692 out_free_tags: 693 blk_mq_free_tag_set(&vblk->tag_set); 694 out_put_disk: 695 put_disk(vblk->disk); 696 out_free_vq: 697 vdev->config->del_vqs(vdev); 698 out_free_vblk: 699 kfree(vblk); 700 out_free_index: 701 ida_simple_remove(&vd_index_ida, index); 702 out: 703 return err; 704 } 705 706 static void virtblk_remove(struct virtio_device *vdev) 707 { 708 struct virtio_blk *vblk = vdev->priv; 709 int index = vblk->index; 710 int refc; 711 712 /* Prevent config work handler from accessing the device. */ 713 mutex_lock(&vblk->config_lock); 714 vblk->config_enable = false; 715 mutex_unlock(&vblk->config_lock); 716 717 del_gendisk(vblk->disk); 718 blk_cleanup_queue(vblk->disk->queue); 719 720 blk_mq_free_tag_set(&vblk->tag_set); 721 722 /* Stop all the virtqueues. */ 723 vdev->config->reset(vdev); 724 725 flush_work(&vblk->config_work); 726 727 refc = atomic_read(&disk_to_dev(vblk->disk)->kobj.kref.refcount); 728 put_disk(vblk->disk); 729 vdev->config->del_vqs(vdev); 730 kfree(vblk); 731 732 /* Only free device id if we don't have any users */ 733 if (refc == 1) 734 ida_simple_remove(&vd_index_ida, index); 735 } 736 737 #ifdef CONFIG_PM_SLEEP 738 static int virtblk_freeze(struct virtio_device *vdev) 739 { 740 struct virtio_blk *vblk = vdev->priv; 741 742 /* Ensure we don't receive any more interrupts */ 743 vdev->config->reset(vdev); 744 745 /* Prevent config work handler from accessing the device. */ 746 mutex_lock(&vblk->config_lock); 747 vblk->config_enable = false; 748 mutex_unlock(&vblk->config_lock); 749 750 flush_work(&vblk->config_work); 751 752 blk_mq_stop_hw_queues(vblk->disk->queue); 753 754 vdev->config->del_vqs(vdev); 755 return 0; 756 } 757 758 static int virtblk_restore(struct virtio_device *vdev) 759 { 760 struct virtio_blk *vblk = vdev->priv; 761 int ret; 762 763 vblk->config_enable = true; 764 ret = init_vq(vdev->priv); 765 if (!ret) 766 blk_mq_start_stopped_hw_queues(vblk->disk->queue, true); 767 768 return ret; 769 } 770 #endif 771 772 static const struct virtio_device_id id_table[] = { 773 { VIRTIO_ID_BLOCK, VIRTIO_DEV_ANY_ID }, 774 { 0 }, 775 }; 776 777 static unsigned int features[] = { 778 VIRTIO_BLK_F_SEG_MAX, VIRTIO_BLK_F_SIZE_MAX, VIRTIO_BLK_F_GEOMETRY, 779 VIRTIO_BLK_F_RO, VIRTIO_BLK_F_BLK_SIZE, VIRTIO_BLK_F_SCSI, 780 VIRTIO_BLK_F_WCE, VIRTIO_BLK_F_TOPOLOGY, VIRTIO_BLK_F_CONFIG_WCE 781 }; 782 783 static struct virtio_driver virtio_blk = { 784 .feature_table = features, 785 .feature_table_size = ARRAY_SIZE(features), 786 .driver.name = KBUILD_MODNAME, 787 .driver.owner = THIS_MODULE, 788 .id_table = id_table, 789 .probe = virtblk_probe, 790 .remove = virtblk_remove, 791 .config_changed = virtblk_config_changed, 792 #ifdef CONFIG_PM_SLEEP 793 .freeze = virtblk_freeze, 794 .restore = virtblk_restore, 795 #endif 796 }; 797 798 static int __init init(void) 799 { 800 int error; 801 802 virtblk_wq = alloc_workqueue("virtio-blk", 0, 0); 803 if (!virtblk_wq) 804 return -ENOMEM; 805 806 major = register_blkdev(0, "virtblk"); 807 if (major < 0) { 808 error = major; 809 goto out_destroy_workqueue; 810 } 811 812 error = register_virtio_driver(&virtio_blk); 813 if (error) 814 goto out_unregister_blkdev; 815 return 0; 816 817 out_unregister_blkdev: 818 unregister_blkdev(major, "virtblk"); 819 out_destroy_workqueue: 820 destroy_workqueue(virtblk_wq); 821 return error; 822 } 823 824 static void __exit fini(void) 825 { 826 unregister_blkdev(major, "virtblk"); 827 unregister_virtio_driver(&virtio_blk); 828 destroy_workqueue(virtblk_wq); 829 } 830 module_init(init); 831 module_exit(fini); 832 833 MODULE_DEVICE_TABLE(virtio, id_table); 834 MODULE_DESCRIPTION("Virtio block driver"); 835 MODULE_LICENSE("GPL"); 836