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 struct virtio_device *vdev; 33 34 /* The disk structure for the kernel. */ 35 struct gendisk *disk; 36 37 /* Block layer tags. */ 38 struct blk_mq_tag_set tag_set; 39 40 /* Process context for config space updates */ 41 struct work_struct config_work; 42 43 /* What host tells us, plus 2 for header & tailer. */ 44 unsigned int sg_elems; 45 46 /* Ida index - used to track minor number allocations. */ 47 int index; 48 49 /* num of vqs */ 50 int num_vqs; 51 struct virtio_blk_vq *vqs; 52 }; 53 54 struct virtblk_req { 55 struct request *req; 56 struct virtio_blk_outhdr out_hdr; 57 struct virtio_scsi_inhdr in_hdr; 58 u8 status; 59 struct scatterlist sg[]; 60 }; 61 62 static inline int virtblk_result(struct virtblk_req *vbr) 63 { 64 switch (vbr->status) { 65 case VIRTIO_BLK_S_OK: 66 return 0; 67 case VIRTIO_BLK_S_UNSUPP: 68 return -ENOTTY; 69 default: 70 return -EIO; 71 } 72 } 73 74 static int __virtblk_add_req(struct virtqueue *vq, 75 struct virtblk_req *vbr, 76 struct scatterlist *data_sg, 77 bool have_data) 78 { 79 struct scatterlist hdr, status, cmd, sense, inhdr, *sgs[6]; 80 unsigned int num_out = 0, num_in = 0; 81 __virtio32 type = vbr->out_hdr.type & ~cpu_to_virtio32(vq->vdev, VIRTIO_BLK_T_OUT); 82 83 sg_init_one(&hdr, &vbr->out_hdr, sizeof(vbr->out_hdr)); 84 sgs[num_out++] = &hdr; 85 86 /* 87 * If this is a packet command we need a couple of additional headers. 88 * Behind the normal outhdr we put a segment with the scsi command 89 * block, and before the normal inhdr we put the sense data and the 90 * inhdr with additional status information. 91 */ 92 if (type == cpu_to_virtio32(vq->vdev, VIRTIO_BLK_T_SCSI_CMD)) { 93 sg_init_one(&cmd, vbr->req->cmd, vbr->req->cmd_len); 94 sgs[num_out++] = &cmd; 95 } 96 97 if (have_data) { 98 if (vbr->out_hdr.type & cpu_to_virtio32(vq->vdev, VIRTIO_BLK_T_OUT)) 99 sgs[num_out++] = data_sg; 100 else 101 sgs[num_out + num_in++] = data_sg; 102 } 103 104 if (type == cpu_to_virtio32(vq->vdev, VIRTIO_BLK_T_SCSI_CMD)) { 105 sg_init_one(&sense, vbr->req->sense, SCSI_SENSE_BUFFERSIZE); 106 sgs[num_out + num_in++] = &sense; 107 sg_init_one(&inhdr, &vbr->in_hdr, sizeof(vbr->in_hdr)); 108 sgs[num_out + num_in++] = &inhdr; 109 } 110 111 sg_init_one(&status, &vbr->status, sizeof(vbr->status)); 112 sgs[num_out + num_in++] = &status; 113 114 return virtqueue_add_sgs(vq, sgs, num_out, num_in, vbr, GFP_ATOMIC); 115 } 116 117 static inline void virtblk_request_done(struct request *req) 118 { 119 struct virtblk_req *vbr = blk_mq_rq_to_pdu(req); 120 struct virtio_blk *vblk = req->q->queuedata; 121 int error = virtblk_result(vbr); 122 123 if (req->cmd_type == REQ_TYPE_BLOCK_PC) { 124 req->resid_len = virtio32_to_cpu(vblk->vdev, vbr->in_hdr.residual); 125 req->sense_len = virtio32_to_cpu(vblk->vdev, vbr->in_hdr.sense_len); 126 req->errors = virtio32_to_cpu(vblk->vdev, vbr->in_hdr.errors); 127 } else if (req->cmd_type == REQ_TYPE_DRV_PRIV) { 128 req->errors = (error != 0); 129 } 130 131 blk_mq_end_request(req, error); 132 } 133 134 static void virtblk_done(struct virtqueue *vq) 135 { 136 struct virtio_blk *vblk = vq->vdev->priv; 137 bool req_done = false; 138 int qid = vq->index; 139 struct virtblk_req *vbr; 140 unsigned long flags; 141 unsigned int len; 142 143 spin_lock_irqsave(&vblk->vqs[qid].lock, flags); 144 do { 145 virtqueue_disable_cb(vq); 146 while ((vbr = virtqueue_get_buf(vblk->vqs[qid].vq, &len)) != NULL) { 147 blk_mq_complete_request(vbr->req, vbr->req->errors); 148 req_done = true; 149 } 150 if (unlikely(virtqueue_is_broken(vq))) 151 break; 152 } while (!virtqueue_enable_cb(vq)); 153 154 /* In case queue is stopped waiting for more buffers. */ 155 if (req_done) 156 blk_mq_start_stopped_hw_queues(vblk->disk->queue, true); 157 spin_unlock_irqrestore(&vblk->vqs[qid].lock, flags); 158 } 159 160 static int virtio_queue_rq(struct blk_mq_hw_ctx *hctx, 161 const struct blk_mq_queue_data *bd) 162 { 163 struct virtio_blk *vblk = hctx->queue->queuedata; 164 struct request *req = bd->rq; 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_op(req) == REQ_OP_FLUSH) { 176 vbr->out_hdr.type = cpu_to_virtio32(vblk->vdev, VIRTIO_BLK_T_FLUSH); 177 vbr->out_hdr.sector = 0; 178 vbr->out_hdr.ioprio = cpu_to_virtio32(vblk->vdev, 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 = cpu_to_virtio64(vblk->vdev, blk_rq_pos(vbr->req)); 184 vbr->out_hdr.ioprio = cpu_to_virtio32(vblk->vdev, req_get_ioprio(vbr->req)); 185 break; 186 case REQ_TYPE_BLOCK_PC: 187 vbr->out_hdr.type = cpu_to_virtio32(vblk->vdev, VIRTIO_BLK_T_SCSI_CMD); 188 vbr->out_hdr.sector = 0; 189 vbr->out_hdr.ioprio = cpu_to_virtio32(vblk->vdev, req_get_ioprio(vbr->req)); 190 break; 191 case REQ_TYPE_DRV_PRIV: 192 vbr->out_hdr.type = cpu_to_virtio32(vblk->vdev, VIRTIO_BLK_T_GET_ID); 193 vbr->out_hdr.sector = 0; 194 vbr->out_hdr.ioprio = cpu_to_virtio32(vblk->vdev, 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 |= cpu_to_virtio32(vblk->vdev, VIRTIO_BLK_T_OUT); 208 else 209 vbr->out_hdr.type |= cpu_to_virtio32(vblk->vdev, 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 (bd->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_queue *q = vblk->disk->queue; 240 struct request *req; 241 int err; 242 243 req = blk_get_request(q, READ, GFP_KERNEL); 244 if (IS_ERR(req)) 245 return PTR_ERR(req); 246 req->cmd_type = REQ_TYPE_DRV_PRIV; 247 248 err = blk_rq_map_kern(q, req, id_str, VIRTIO_BLK_ID_BYTES, GFP_KERNEL); 249 if (err) 250 goto out; 251 252 err = blk_execute_rq(vblk->disk->queue, vblk->disk, req, false); 253 out: 254 blk_put_request(req); 255 return err; 256 } 257 258 static int virtblk_ioctl(struct block_device *bdev, fmode_t mode, 259 unsigned int cmd, unsigned long data) 260 { 261 struct gendisk *disk = bdev->bd_disk; 262 struct virtio_blk *vblk = disk->private_data; 263 264 /* 265 * Only allow the generic SCSI ioctls if the host can support it. 266 */ 267 if (!virtio_has_feature(vblk->vdev, VIRTIO_BLK_F_SCSI)) 268 return -ENOTTY; 269 270 return scsi_cmd_blk_ioctl(bdev, mode, cmd, 271 (void __user *)data); 272 } 273 274 /* We provide getgeo only to please some old bootloader/partitioning tools */ 275 static int virtblk_getgeo(struct block_device *bd, struct hd_geometry *geo) 276 { 277 struct virtio_blk *vblk = bd->bd_disk->private_data; 278 279 /* see if the host passed in geometry config */ 280 if (virtio_has_feature(vblk->vdev, VIRTIO_BLK_F_GEOMETRY)) { 281 virtio_cread(vblk->vdev, struct virtio_blk_config, 282 geometry.cylinders, &geo->cylinders); 283 virtio_cread(vblk->vdev, struct virtio_blk_config, 284 geometry.heads, &geo->heads); 285 virtio_cread(vblk->vdev, struct virtio_blk_config, 286 geometry.sectors, &geo->sectors); 287 } else { 288 /* some standard values, similar to sd */ 289 geo->heads = 1 << 6; 290 geo->sectors = 1 << 5; 291 geo->cylinders = get_capacity(bd->bd_disk) >> 11; 292 } 293 return 0; 294 } 295 296 static const struct block_device_operations virtblk_fops = { 297 .ioctl = virtblk_ioctl, 298 .owner = THIS_MODULE, 299 .getgeo = virtblk_getgeo, 300 }; 301 302 static int index_to_minor(int index) 303 { 304 return index << PART_BITS; 305 } 306 307 static int minor_to_index(int minor) 308 { 309 return minor >> PART_BITS; 310 } 311 312 static ssize_t virtblk_serial_show(struct device *dev, 313 struct device_attribute *attr, char *buf) 314 { 315 struct gendisk *disk = dev_to_disk(dev); 316 int err; 317 318 /* sysfs gives us a PAGE_SIZE buffer */ 319 BUILD_BUG_ON(PAGE_SIZE < VIRTIO_BLK_ID_BYTES); 320 321 buf[VIRTIO_BLK_ID_BYTES] = '\0'; 322 err = virtblk_get_id(disk, buf); 323 if (!err) 324 return strlen(buf); 325 326 if (err == -EIO) /* Unsupported? Make it empty. */ 327 return 0; 328 329 return err; 330 } 331 332 static DEVICE_ATTR(serial, S_IRUGO, virtblk_serial_show, NULL); 333 334 static void virtblk_config_changed_work(struct work_struct *work) 335 { 336 struct virtio_blk *vblk = 337 container_of(work, struct virtio_blk, config_work); 338 struct virtio_device *vdev = vblk->vdev; 339 struct request_queue *q = vblk->disk->queue; 340 char cap_str_2[10], cap_str_10[10]; 341 char *envp[] = { "RESIZE=1", NULL }; 342 u64 capacity; 343 344 /* Host must always specify the capacity. */ 345 virtio_cread(vdev, struct virtio_blk_config, capacity, &capacity); 346 347 /* If capacity is too big, truncate with warning. */ 348 if ((sector_t)capacity != capacity) { 349 dev_warn(&vdev->dev, "Capacity %llu too large: truncating\n", 350 (unsigned long long)capacity); 351 capacity = (sector_t)-1; 352 } 353 354 string_get_size(capacity, queue_logical_block_size(q), 355 STRING_UNITS_2, cap_str_2, sizeof(cap_str_2)); 356 string_get_size(capacity, queue_logical_block_size(q), 357 STRING_UNITS_10, cap_str_10, sizeof(cap_str_10)); 358 359 dev_notice(&vdev->dev, 360 "new size: %llu %d-byte logical blocks (%s/%s)\n", 361 (unsigned long long)capacity, 362 queue_logical_block_size(q), 363 cap_str_10, cap_str_2); 364 365 set_capacity(vblk->disk, capacity); 366 revalidate_disk(vblk->disk); 367 kobject_uevent_env(&disk_to_dev(vblk->disk)->kobj, KOBJ_CHANGE, envp); 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 int i; 381 vq_callback_t **callbacks; 382 const char **names; 383 struct virtqueue **vqs; 384 unsigned short num_vqs; 385 struct virtio_device *vdev = vblk->vdev; 386 387 err = virtio_cread_feature(vdev, VIRTIO_BLK_F_MQ, 388 struct virtio_blk_config, num_queues, 389 &num_vqs); 390 if (err) 391 num_vqs = 1; 392 393 vblk->vqs = kmalloc(sizeof(*vblk->vqs) * num_vqs, GFP_KERNEL); 394 if (!vblk->vqs) 395 return -ENOMEM; 396 397 names = kmalloc(sizeof(*names) * num_vqs, GFP_KERNEL); 398 callbacks = kmalloc(sizeof(*callbacks) * num_vqs, GFP_KERNEL); 399 vqs = kmalloc(sizeof(*vqs) * num_vqs, GFP_KERNEL); 400 if (!names || !callbacks || !vqs) { 401 err = -ENOMEM; 402 goto out; 403 } 404 405 for (i = 0; i < num_vqs; i++) { 406 callbacks[i] = virtblk_done; 407 snprintf(vblk->vqs[i].name, VQ_NAME_LEN, "req.%d", i); 408 names[i] = vblk->vqs[i].name; 409 } 410 411 /* Discover virtqueues and write information to configuration. */ 412 err = vdev->config->find_vqs(vdev, num_vqs, vqs, callbacks, names); 413 if (err) 414 goto out; 415 416 for (i = 0; i < num_vqs; i++) { 417 spin_lock_init(&vblk->vqs[i].lock); 418 vblk->vqs[i].vq = vqs[i]; 419 } 420 vblk->num_vqs = num_vqs; 421 422 out: 423 kfree(vqs); 424 kfree(callbacks); 425 kfree(names); 426 if (err) 427 kfree(vblk->vqs); 428 return err; 429 } 430 431 /* 432 * Legacy naming scheme used for virtio devices. We are stuck with it for 433 * virtio blk but don't ever use it for any new driver. 434 */ 435 static int virtblk_name_format(char *prefix, int index, char *buf, int buflen) 436 { 437 const int base = 'z' - 'a' + 1; 438 char *begin = buf + strlen(prefix); 439 char *end = buf + buflen; 440 char *p; 441 int unit; 442 443 p = end - 1; 444 *p = '\0'; 445 unit = base; 446 do { 447 if (p == begin) 448 return -EINVAL; 449 *--p = 'a' + (index % unit); 450 index = (index / unit) - 1; 451 } while (index >= 0); 452 453 memmove(begin, p, end - p); 454 memcpy(buf, prefix, strlen(prefix)); 455 456 return 0; 457 } 458 459 static int virtblk_get_cache_mode(struct virtio_device *vdev) 460 { 461 u8 writeback; 462 int err; 463 464 err = virtio_cread_feature(vdev, VIRTIO_BLK_F_CONFIG_WCE, 465 struct virtio_blk_config, wce, 466 &writeback); 467 468 /* 469 * If WCE is not configurable and flush is not available, 470 * assume no writeback cache is in use. 471 */ 472 if (err) 473 writeback = virtio_has_feature(vdev, VIRTIO_BLK_F_FLUSH); 474 475 return writeback; 476 } 477 478 static void virtblk_update_cache_mode(struct virtio_device *vdev) 479 { 480 u8 writeback = virtblk_get_cache_mode(vdev); 481 struct virtio_blk *vblk = vdev->priv; 482 483 blk_queue_write_cache(vblk->disk->queue, writeback, false); 484 revalidate_disk(vblk->disk); 485 } 486 487 static const char *const virtblk_cache_types[] = { 488 "write through", "write back" 489 }; 490 491 static ssize_t 492 virtblk_cache_type_store(struct device *dev, struct device_attribute *attr, 493 const char *buf, size_t count) 494 { 495 struct gendisk *disk = dev_to_disk(dev); 496 struct virtio_blk *vblk = disk->private_data; 497 struct virtio_device *vdev = vblk->vdev; 498 int i; 499 500 BUG_ON(!virtio_has_feature(vblk->vdev, VIRTIO_BLK_F_CONFIG_WCE)); 501 for (i = ARRAY_SIZE(virtblk_cache_types); --i >= 0; ) 502 if (sysfs_streq(buf, virtblk_cache_types[i])) 503 break; 504 505 if (i < 0) 506 return -EINVAL; 507 508 virtio_cwrite8(vdev, offsetof(struct virtio_blk_config, wce), i); 509 virtblk_update_cache_mode(vdev); 510 return count; 511 } 512 513 static ssize_t 514 virtblk_cache_type_show(struct device *dev, struct device_attribute *attr, 515 char *buf) 516 { 517 struct gendisk *disk = dev_to_disk(dev); 518 struct virtio_blk *vblk = disk->private_data; 519 u8 writeback = virtblk_get_cache_mode(vblk->vdev); 520 521 BUG_ON(writeback >= ARRAY_SIZE(virtblk_cache_types)); 522 return snprintf(buf, 40, "%s\n", virtblk_cache_types[writeback]); 523 } 524 525 static const struct device_attribute dev_attr_cache_type_ro = 526 __ATTR(cache_type, S_IRUGO, 527 virtblk_cache_type_show, NULL); 528 static const struct device_attribute dev_attr_cache_type_rw = 529 __ATTR(cache_type, S_IRUGO|S_IWUSR, 530 virtblk_cache_type_show, virtblk_cache_type_store); 531 532 static int virtblk_init_request(void *data, struct request *rq, 533 unsigned int hctx_idx, unsigned int request_idx, 534 unsigned int numa_node) 535 { 536 struct virtio_blk *vblk = data; 537 struct virtblk_req *vbr = blk_mq_rq_to_pdu(rq); 538 539 sg_init_table(vbr->sg, vblk->sg_elems); 540 return 0; 541 } 542 543 static struct blk_mq_ops virtio_mq_ops = { 544 .queue_rq = virtio_queue_rq, 545 .map_queue = blk_mq_map_queue, 546 .complete = virtblk_request_done, 547 .init_request = virtblk_init_request, 548 }; 549 550 static unsigned int virtblk_queue_depth; 551 module_param_named(queue_depth, virtblk_queue_depth, uint, 0444); 552 553 static int virtblk_probe(struct virtio_device *vdev) 554 { 555 struct virtio_blk *vblk; 556 struct request_queue *q; 557 int err, index; 558 559 u64 cap; 560 u32 v, blk_size, sg_elems, opt_io_size; 561 u16 min_io_size; 562 u8 physical_block_exp, alignment_offset; 563 564 if (!vdev->config->get) { 565 dev_err(&vdev->dev, "%s failure: config access disabled\n", 566 __func__); 567 return -EINVAL; 568 } 569 570 err = ida_simple_get(&vd_index_ida, 0, minor_to_index(1 << MINORBITS), 571 GFP_KERNEL); 572 if (err < 0) 573 goto out; 574 index = err; 575 576 /* We need to know how many segments before we allocate. */ 577 err = virtio_cread_feature(vdev, VIRTIO_BLK_F_SEG_MAX, 578 struct virtio_blk_config, seg_max, 579 &sg_elems); 580 581 /* We need at least one SG element, whatever they say. */ 582 if (err || !sg_elems) 583 sg_elems = 1; 584 585 /* We need an extra sg elements at head and tail. */ 586 sg_elems += 2; 587 vdev->priv = vblk = kmalloc(sizeof(*vblk), GFP_KERNEL); 588 if (!vblk) { 589 err = -ENOMEM; 590 goto out_free_index; 591 } 592 593 vblk->vdev = vdev; 594 vblk->sg_elems = sg_elems; 595 596 INIT_WORK(&vblk->config_work, virtblk_config_changed_work); 597 598 err = init_vq(vblk); 599 if (err) 600 goto out_free_vblk; 601 602 /* FIXME: How many partitions? How long is a piece of string? */ 603 vblk->disk = alloc_disk(1 << PART_BITS); 604 if (!vblk->disk) { 605 err = -ENOMEM; 606 goto out_free_vq; 607 } 608 609 /* Default queue sizing is to fill the ring. */ 610 if (!virtblk_queue_depth) { 611 virtblk_queue_depth = vblk->vqs[0].vq->num_free; 612 /* ... but without indirect descs, we use 2 descs per req */ 613 if (!virtio_has_feature(vdev, VIRTIO_RING_F_INDIRECT_DESC)) 614 virtblk_queue_depth /= 2; 615 } 616 617 memset(&vblk->tag_set, 0, sizeof(vblk->tag_set)); 618 vblk->tag_set.ops = &virtio_mq_ops; 619 vblk->tag_set.queue_depth = virtblk_queue_depth; 620 vblk->tag_set.numa_node = NUMA_NO_NODE; 621 vblk->tag_set.flags = BLK_MQ_F_SHOULD_MERGE; 622 vblk->tag_set.cmd_size = 623 sizeof(struct virtblk_req) + 624 sizeof(struct scatterlist) * sg_elems; 625 vblk->tag_set.driver_data = vblk; 626 vblk->tag_set.nr_hw_queues = vblk->num_vqs; 627 628 err = blk_mq_alloc_tag_set(&vblk->tag_set); 629 if (err) 630 goto out_put_disk; 631 632 q = vblk->disk->queue = blk_mq_init_queue(&vblk->tag_set); 633 if (IS_ERR(q)) { 634 err = -ENOMEM; 635 goto out_free_tags; 636 } 637 638 q->queuedata = vblk; 639 640 virtblk_name_format("vd", index, vblk->disk->disk_name, DISK_NAME_LEN); 641 642 vblk->disk->major = major; 643 vblk->disk->first_minor = index_to_minor(index); 644 vblk->disk->private_data = vblk; 645 vblk->disk->fops = &virtblk_fops; 646 vblk->disk->flags |= GENHD_FL_EXT_DEVT; 647 vblk->index = index; 648 649 /* configure queue flush support */ 650 virtblk_update_cache_mode(vdev); 651 652 /* If disk is read-only in the host, the guest should obey */ 653 if (virtio_has_feature(vdev, VIRTIO_BLK_F_RO)) 654 set_disk_ro(vblk->disk, 1); 655 656 /* Host must always specify the capacity. */ 657 virtio_cread(vdev, struct virtio_blk_config, capacity, &cap); 658 659 /* If capacity is too big, truncate with warning. */ 660 if ((sector_t)cap != cap) { 661 dev_warn(&vdev->dev, "Capacity %llu too large: truncating\n", 662 (unsigned long long)cap); 663 cap = (sector_t)-1; 664 } 665 set_capacity(vblk->disk, cap); 666 667 /* We can handle whatever the host told us to handle. */ 668 blk_queue_max_segments(q, vblk->sg_elems-2); 669 670 /* No need to bounce any requests */ 671 blk_queue_bounce_limit(q, BLK_BOUNCE_ANY); 672 673 /* No real sector limit. */ 674 blk_queue_max_hw_sectors(q, -1U); 675 676 /* Host can optionally specify maximum segment size and number of 677 * segments. */ 678 err = virtio_cread_feature(vdev, VIRTIO_BLK_F_SIZE_MAX, 679 struct virtio_blk_config, size_max, &v); 680 if (!err) 681 blk_queue_max_segment_size(q, v); 682 else 683 blk_queue_max_segment_size(q, -1U); 684 685 /* Host can optionally specify the block size of the device */ 686 err = virtio_cread_feature(vdev, VIRTIO_BLK_F_BLK_SIZE, 687 struct virtio_blk_config, blk_size, 688 &blk_size); 689 if (!err) 690 blk_queue_logical_block_size(q, blk_size); 691 else 692 blk_size = queue_logical_block_size(q); 693 694 /* Use topology information if available */ 695 err = virtio_cread_feature(vdev, VIRTIO_BLK_F_TOPOLOGY, 696 struct virtio_blk_config, physical_block_exp, 697 &physical_block_exp); 698 if (!err && physical_block_exp) 699 blk_queue_physical_block_size(q, 700 blk_size * (1 << physical_block_exp)); 701 702 err = virtio_cread_feature(vdev, VIRTIO_BLK_F_TOPOLOGY, 703 struct virtio_blk_config, alignment_offset, 704 &alignment_offset); 705 if (!err && alignment_offset) 706 blk_queue_alignment_offset(q, blk_size * alignment_offset); 707 708 err = virtio_cread_feature(vdev, VIRTIO_BLK_F_TOPOLOGY, 709 struct virtio_blk_config, min_io_size, 710 &min_io_size); 711 if (!err && min_io_size) 712 blk_queue_io_min(q, blk_size * min_io_size); 713 714 err = virtio_cread_feature(vdev, VIRTIO_BLK_F_TOPOLOGY, 715 struct virtio_blk_config, opt_io_size, 716 &opt_io_size); 717 if (!err && opt_io_size) 718 blk_queue_io_opt(q, blk_size * opt_io_size); 719 720 virtio_device_ready(vdev); 721 722 device_add_disk(&vdev->dev, vblk->disk); 723 err = device_create_file(disk_to_dev(vblk->disk), &dev_attr_serial); 724 if (err) 725 goto out_del_disk; 726 727 if (virtio_has_feature(vdev, VIRTIO_BLK_F_CONFIG_WCE)) 728 err = device_create_file(disk_to_dev(vblk->disk), 729 &dev_attr_cache_type_rw); 730 else 731 err = device_create_file(disk_to_dev(vblk->disk), 732 &dev_attr_cache_type_ro); 733 if (err) 734 goto out_del_disk; 735 return 0; 736 737 out_del_disk: 738 del_gendisk(vblk->disk); 739 blk_cleanup_queue(vblk->disk->queue); 740 out_free_tags: 741 blk_mq_free_tag_set(&vblk->tag_set); 742 out_put_disk: 743 put_disk(vblk->disk); 744 out_free_vq: 745 vdev->config->del_vqs(vdev); 746 out_free_vblk: 747 kfree(vblk); 748 out_free_index: 749 ida_simple_remove(&vd_index_ida, index); 750 out: 751 return err; 752 } 753 754 static void virtblk_remove(struct virtio_device *vdev) 755 { 756 struct virtio_blk *vblk = vdev->priv; 757 int index = vblk->index; 758 int refc; 759 760 /* Make sure no work handler is accessing the device. */ 761 flush_work(&vblk->config_work); 762 763 del_gendisk(vblk->disk); 764 blk_cleanup_queue(vblk->disk->queue); 765 766 blk_mq_free_tag_set(&vblk->tag_set); 767 768 /* Stop all the virtqueues. */ 769 vdev->config->reset(vdev); 770 771 refc = atomic_read(&disk_to_dev(vblk->disk)->kobj.kref.refcount); 772 put_disk(vblk->disk); 773 vdev->config->del_vqs(vdev); 774 kfree(vblk->vqs); 775 kfree(vblk); 776 777 /* Only free device id if we don't have any users */ 778 if (refc == 1) 779 ida_simple_remove(&vd_index_ida, index); 780 } 781 782 #ifdef CONFIG_PM_SLEEP 783 static int virtblk_freeze(struct virtio_device *vdev) 784 { 785 struct virtio_blk *vblk = vdev->priv; 786 787 /* Ensure we don't receive any more interrupts */ 788 vdev->config->reset(vdev); 789 790 /* Make sure no work handler is accessing the device. */ 791 flush_work(&vblk->config_work); 792 793 blk_mq_stop_hw_queues(vblk->disk->queue); 794 795 vdev->config->del_vqs(vdev); 796 return 0; 797 } 798 799 static int virtblk_restore(struct virtio_device *vdev) 800 { 801 struct virtio_blk *vblk = vdev->priv; 802 int ret; 803 804 ret = init_vq(vdev->priv); 805 if (ret) 806 return ret; 807 808 virtio_device_ready(vdev); 809 810 blk_mq_start_stopped_hw_queues(vblk->disk->queue, true); 811 return 0; 812 } 813 #endif 814 815 static const struct virtio_device_id id_table[] = { 816 { VIRTIO_ID_BLOCK, VIRTIO_DEV_ANY_ID }, 817 { 0 }, 818 }; 819 820 static unsigned int features_legacy[] = { 821 VIRTIO_BLK_F_SEG_MAX, VIRTIO_BLK_F_SIZE_MAX, VIRTIO_BLK_F_GEOMETRY, 822 VIRTIO_BLK_F_RO, VIRTIO_BLK_F_BLK_SIZE, VIRTIO_BLK_F_SCSI, 823 VIRTIO_BLK_F_FLUSH, VIRTIO_BLK_F_TOPOLOGY, VIRTIO_BLK_F_CONFIG_WCE, 824 VIRTIO_BLK_F_MQ, 825 } 826 ; 827 static unsigned int features[] = { 828 VIRTIO_BLK_F_SEG_MAX, VIRTIO_BLK_F_SIZE_MAX, VIRTIO_BLK_F_GEOMETRY, 829 VIRTIO_BLK_F_RO, VIRTIO_BLK_F_BLK_SIZE, 830 VIRTIO_BLK_F_FLUSH, VIRTIO_BLK_F_TOPOLOGY, VIRTIO_BLK_F_CONFIG_WCE, 831 VIRTIO_BLK_F_MQ, 832 }; 833 834 static struct virtio_driver virtio_blk = { 835 .feature_table = features, 836 .feature_table_size = ARRAY_SIZE(features), 837 .feature_table_legacy = features_legacy, 838 .feature_table_size_legacy = ARRAY_SIZE(features_legacy), 839 .driver.name = KBUILD_MODNAME, 840 .driver.owner = THIS_MODULE, 841 .id_table = id_table, 842 .probe = virtblk_probe, 843 .remove = virtblk_remove, 844 .config_changed = virtblk_config_changed, 845 #ifdef CONFIG_PM_SLEEP 846 .freeze = virtblk_freeze, 847 .restore = virtblk_restore, 848 #endif 849 }; 850 851 static int __init init(void) 852 { 853 int error; 854 855 virtblk_wq = alloc_workqueue("virtio-blk", 0, 0); 856 if (!virtblk_wq) 857 return -ENOMEM; 858 859 major = register_blkdev(0, "virtblk"); 860 if (major < 0) { 861 error = major; 862 goto out_destroy_workqueue; 863 } 864 865 error = register_virtio_driver(&virtio_blk); 866 if (error) 867 goto out_unregister_blkdev; 868 return 0; 869 870 out_unregister_blkdev: 871 unregister_blkdev(major, "virtblk"); 872 out_destroy_workqueue: 873 destroy_workqueue(virtblk_wq); 874 return error; 875 } 876 877 static void __exit fini(void) 878 { 879 unregister_virtio_driver(&virtio_blk); 880 unregister_blkdev(major, "virtblk"); 881 destroy_workqueue(virtblk_wq); 882 } 883 module_init(init); 884 module_exit(fini); 885 886 MODULE_DEVICE_TABLE(virtio, id_table); 887 MODULE_DESCRIPTION("Virtio block driver"); 888 MODULE_LICENSE("GPL"); 889