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