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/interrupt.h> 9 #include <linux/virtio.h> 10 #include <linux/virtio_blk.h> 11 #include <linux/scatterlist.h> 12 #include <linux/string_helpers.h> 13 #include <scsi/scsi_cmnd.h> 14 #include <linux/idr.h> 15 #include <linux/blk-mq.h> 16 #include <linux/blk-mq-virtio.h> 17 #include <linux/numa.h> 18 19 #define PART_BITS 4 20 #define VQ_NAME_LEN 16 21 22 static int major; 23 static DEFINE_IDA(vd_index_ida); 24 25 static struct workqueue_struct *virtblk_wq; 26 27 struct virtio_blk_vq { 28 struct virtqueue *vq; 29 spinlock_t lock; 30 char name[VQ_NAME_LEN]; 31 } ____cacheline_aligned_in_smp; 32 33 struct virtio_blk { 34 struct virtio_device *vdev; 35 36 /* The disk structure for the kernel. */ 37 struct gendisk *disk; 38 39 /* Block layer tags. */ 40 struct blk_mq_tag_set tag_set; 41 42 /* Process context for config space updates */ 43 struct work_struct config_work; 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 /* num of vqs */ 52 int num_vqs; 53 struct virtio_blk_vq *vqs; 54 }; 55 56 struct virtblk_req { 57 #ifdef CONFIG_VIRTIO_BLK_SCSI 58 struct scsi_request sreq; /* for SCSI passthrough, must be first */ 59 u8 sense[SCSI_SENSE_BUFFERSIZE]; 60 struct virtio_scsi_inhdr in_hdr; 61 #endif 62 struct virtio_blk_outhdr out_hdr; 63 u8 status; 64 struct scatterlist sg[]; 65 }; 66 67 static inline blk_status_t virtblk_result(struct virtblk_req *vbr) 68 { 69 switch (vbr->status) { 70 case VIRTIO_BLK_S_OK: 71 return BLK_STS_OK; 72 case VIRTIO_BLK_S_UNSUPP: 73 return BLK_STS_NOTSUPP; 74 default: 75 return BLK_STS_IOERR; 76 } 77 } 78 79 /* 80 * If this is a packet command we need a couple of additional headers. Behind 81 * the normal outhdr we put a segment with the scsi command block, and before 82 * the normal inhdr we put the sense data and the inhdr with additional status 83 * information. 84 */ 85 #ifdef CONFIG_VIRTIO_BLK_SCSI 86 static int virtblk_add_req_scsi(struct virtqueue *vq, struct virtblk_req *vbr, 87 struct scatterlist *data_sg, bool have_data) 88 { 89 struct scatterlist hdr, status, cmd, sense, inhdr, *sgs[6]; 90 unsigned int num_out = 0, num_in = 0; 91 92 sg_init_one(&hdr, &vbr->out_hdr, sizeof(vbr->out_hdr)); 93 sgs[num_out++] = &hdr; 94 sg_init_one(&cmd, vbr->sreq.cmd, vbr->sreq.cmd_len); 95 sgs[num_out++] = &cmd; 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 sg_init_one(&sense, vbr->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 sg_init_one(&status, &vbr->status, sizeof(vbr->status)); 109 sgs[num_out + num_in++] = &status; 110 111 return virtqueue_add_sgs(vq, sgs, num_out, num_in, vbr, GFP_ATOMIC); 112 } 113 114 static inline void virtblk_scsi_request_done(struct request *req) 115 { 116 struct virtblk_req *vbr = blk_mq_rq_to_pdu(req); 117 struct virtio_blk *vblk = req->q->queuedata; 118 struct scsi_request *sreq = &vbr->sreq; 119 120 sreq->resid_len = virtio32_to_cpu(vblk->vdev, vbr->in_hdr.residual); 121 sreq->sense_len = virtio32_to_cpu(vblk->vdev, vbr->in_hdr.sense_len); 122 sreq->result = virtio32_to_cpu(vblk->vdev, vbr->in_hdr.errors); 123 } 124 125 static int virtblk_ioctl(struct block_device *bdev, fmode_t mode, 126 unsigned int cmd, unsigned long data) 127 { 128 struct gendisk *disk = bdev->bd_disk; 129 struct virtio_blk *vblk = disk->private_data; 130 131 /* 132 * Only allow the generic SCSI ioctls if the host can support it. 133 */ 134 if (!virtio_has_feature(vblk->vdev, VIRTIO_BLK_F_SCSI)) 135 return -ENOTTY; 136 137 return scsi_cmd_blk_ioctl(bdev, mode, cmd, 138 (void __user *)data); 139 } 140 #else 141 static inline int virtblk_add_req_scsi(struct virtqueue *vq, 142 struct virtblk_req *vbr, struct scatterlist *data_sg, 143 bool have_data) 144 { 145 return -EIO; 146 } 147 static inline void virtblk_scsi_request_done(struct request *req) 148 { 149 } 150 #define virtblk_ioctl NULL 151 #endif /* CONFIG_VIRTIO_BLK_SCSI */ 152 153 static int virtblk_add_req(struct virtqueue *vq, struct virtblk_req *vbr, 154 struct scatterlist *data_sg, bool have_data) 155 { 156 struct scatterlist hdr, status, *sgs[3]; 157 unsigned int num_out = 0, num_in = 0; 158 159 sg_init_one(&hdr, &vbr->out_hdr, sizeof(vbr->out_hdr)); 160 sgs[num_out++] = &hdr; 161 162 if (have_data) { 163 if (vbr->out_hdr.type & cpu_to_virtio32(vq->vdev, VIRTIO_BLK_T_OUT)) 164 sgs[num_out++] = data_sg; 165 else 166 sgs[num_out + num_in++] = data_sg; 167 } 168 169 sg_init_one(&status, &vbr->status, sizeof(vbr->status)); 170 sgs[num_out + num_in++] = &status; 171 172 return virtqueue_add_sgs(vq, sgs, num_out, num_in, vbr, GFP_ATOMIC); 173 } 174 175 static inline void virtblk_request_done(struct request *req) 176 { 177 struct virtblk_req *vbr = blk_mq_rq_to_pdu(req); 178 179 switch (req_op(req)) { 180 case REQ_OP_SCSI_IN: 181 case REQ_OP_SCSI_OUT: 182 virtblk_scsi_request_done(req); 183 break; 184 } 185 186 blk_mq_end_request(req, virtblk_result(vbr)); 187 } 188 189 static void virtblk_done(struct virtqueue *vq) 190 { 191 struct virtio_blk *vblk = vq->vdev->priv; 192 bool req_done = false; 193 int qid = vq->index; 194 struct virtblk_req *vbr; 195 unsigned long flags; 196 unsigned int len; 197 198 spin_lock_irqsave(&vblk->vqs[qid].lock, flags); 199 do { 200 virtqueue_disable_cb(vq); 201 while ((vbr = virtqueue_get_buf(vblk->vqs[qid].vq, &len)) != NULL) { 202 struct request *req = blk_mq_rq_from_pdu(vbr); 203 204 blk_mq_complete_request(req); 205 req_done = true; 206 } 207 if (unlikely(virtqueue_is_broken(vq))) 208 break; 209 } while (!virtqueue_enable_cb(vq)); 210 211 /* In case queue is stopped waiting for more buffers. */ 212 if (req_done) 213 blk_mq_start_stopped_hw_queues(vblk->disk->queue, true); 214 spin_unlock_irqrestore(&vblk->vqs[qid].lock, flags); 215 } 216 217 static blk_status_t virtio_queue_rq(struct blk_mq_hw_ctx *hctx, 218 const struct blk_mq_queue_data *bd) 219 { 220 struct virtio_blk *vblk = hctx->queue->queuedata; 221 struct request *req = bd->rq; 222 struct virtblk_req *vbr = blk_mq_rq_to_pdu(req); 223 unsigned long flags; 224 unsigned int num; 225 int qid = hctx->queue_num; 226 int err; 227 bool notify = false; 228 u32 type; 229 230 BUG_ON(req->nr_phys_segments + 2 > vblk->sg_elems); 231 232 switch (req_op(req)) { 233 case REQ_OP_READ: 234 case REQ_OP_WRITE: 235 type = 0; 236 break; 237 case REQ_OP_FLUSH: 238 type = VIRTIO_BLK_T_FLUSH; 239 break; 240 case REQ_OP_SCSI_IN: 241 case REQ_OP_SCSI_OUT: 242 type = VIRTIO_BLK_T_SCSI_CMD; 243 break; 244 case REQ_OP_DRV_IN: 245 type = VIRTIO_BLK_T_GET_ID; 246 break; 247 default: 248 WARN_ON_ONCE(1); 249 return BLK_STS_IOERR; 250 } 251 252 vbr->out_hdr.type = cpu_to_virtio32(vblk->vdev, type); 253 vbr->out_hdr.sector = type ? 254 0 : cpu_to_virtio64(vblk->vdev, blk_rq_pos(req)); 255 vbr->out_hdr.ioprio = cpu_to_virtio32(vblk->vdev, req_get_ioprio(req)); 256 257 blk_mq_start_request(req); 258 259 num = blk_rq_map_sg(hctx->queue, req, vbr->sg); 260 if (num) { 261 if (rq_data_dir(req) == WRITE) 262 vbr->out_hdr.type |= cpu_to_virtio32(vblk->vdev, VIRTIO_BLK_T_OUT); 263 else 264 vbr->out_hdr.type |= cpu_to_virtio32(vblk->vdev, VIRTIO_BLK_T_IN); 265 } 266 267 spin_lock_irqsave(&vblk->vqs[qid].lock, flags); 268 if (blk_rq_is_scsi(req)) 269 err = virtblk_add_req_scsi(vblk->vqs[qid].vq, vbr, vbr->sg, num); 270 else 271 err = virtblk_add_req(vblk->vqs[qid].vq, vbr, vbr->sg, num); 272 if (err) { 273 virtqueue_kick(vblk->vqs[qid].vq); 274 blk_mq_stop_hw_queue(hctx); 275 spin_unlock_irqrestore(&vblk->vqs[qid].lock, flags); 276 /* Out of mem doesn't actually happen, since we fall back 277 * to direct descriptors */ 278 if (err == -ENOMEM || err == -ENOSPC) 279 return BLK_STS_RESOURCE; 280 return BLK_STS_IOERR; 281 } 282 283 if (bd->last && virtqueue_kick_prepare(vblk->vqs[qid].vq)) 284 notify = true; 285 spin_unlock_irqrestore(&vblk->vqs[qid].lock, flags); 286 287 if (notify) 288 virtqueue_notify(vblk->vqs[qid].vq); 289 return BLK_STS_OK; 290 } 291 292 /* return id (s/n) string for *disk to *id_str 293 */ 294 static int virtblk_get_id(struct gendisk *disk, char *id_str) 295 { 296 struct virtio_blk *vblk = disk->private_data; 297 struct request_queue *q = vblk->disk->queue; 298 struct request *req; 299 int err; 300 301 req = blk_get_request(q, REQ_OP_DRV_IN, GFP_KERNEL); 302 if (IS_ERR(req)) 303 return PTR_ERR(req); 304 305 err = blk_rq_map_kern(q, req, id_str, VIRTIO_BLK_ID_BYTES, GFP_KERNEL); 306 if (err) 307 goto out; 308 309 blk_execute_rq(vblk->disk->queue, vblk->disk, req, false); 310 err = blk_status_to_errno(virtblk_result(blk_mq_rq_to_pdu(req))); 311 out: 312 blk_put_request(req); 313 return err; 314 } 315 316 /* We provide getgeo only to please some old bootloader/partitioning tools */ 317 static int virtblk_getgeo(struct block_device *bd, struct hd_geometry *geo) 318 { 319 struct virtio_blk *vblk = bd->bd_disk->private_data; 320 321 /* see if the host passed in geometry config */ 322 if (virtio_has_feature(vblk->vdev, VIRTIO_BLK_F_GEOMETRY)) { 323 virtio_cread(vblk->vdev, struct virtio_blk_config, 324 geometry.cylinders, &geo->cylinders); 325 virtio_cread(vblk->vdev, struct virtio_blk_config, 326 geometry.heads, &geo->heads); 327 virtio_cread(vblk->vdev, struct virtio_blk_config, 328 geometry.sectors, &geo->sectors); 329 } else { 330 /* some standard values, similar to sd */ 331 geo->heads = 1 << 6; 332 geo->sectors = 1 << 5; 333 geo->cylinders = get_capacity(bd->bd_disk) >> 11; 334 } 335 return 0; 336 } 337 338 static const struct block_device_operations virtblk_fops = { 339 .ioctl = virtblk_ioctl, 340 .owner = THIS_MODULE, 341 .getgeo = virtblk_getgeo, 342 }; 343 344 static int index_to_minor(int index) 345 { 346 return index << PART_BITS; 347 } 348 349 static int minor_to_index(int minor) 350 { 351 return minor >> PART_BITS; 352 } 353 354 static ssize_t virtblk_serial_show(struct device *dev, 355 struct device_attribute *attr, char *buf) 356 { 357 struct gendisk *disk = dev_to_disk(dev); 358 int err; 359 360 /* sysfs gives us a PAGE_SIZE buffer */ 361 BUILD_BUG_ON(PAGE_SIZE < VIRTIO_BLK_ID_BYTES); 362 363 buf[VIRTIO_BLK_ID_BYTES] = '\0'; 364 err = virtblk_get_id(disk, buf); 365 if (!err) 366 return strlen(buf); 367 368 if (err == -EIO) /* Unsupported? Make it empty. */ 369 return 0; 370 371 return err; 372 } 373 374 static DEVICE_ATTR(serial, S_IRUGO, virtblk_serial_show, NULL); 375 376 static void virtblk_config_changed_work(struct work_struct *work) 377 { 378 struct virtio_blk *vblk = 379 container_of(work, struct virtio_blk, config_work); 380 struct virtio_device *vdev = vblk->vdev; 381 struct request_queue *q = vblk->disk->queue; 382 char cap_str_2[10], cap_str_10[10]; 383 char *envp[] = { "RESIZE=1", NULL }; 384 unsigned long long nblocks; 385 u64 capacity; 386 387 /* Host must always specify the capacity. */ 388 virtio_cread(vdev, struct virtio_blk_config, capacity, &capacity); 389 390 /* If capacity is too big, truncate with warning. */ 391 if ((sector_t)capacity != capacity) { 392 dev_warn(&vdev->dev, "Capacity %llu too large: truncating\n", 393 (unsigned long long)capacity); 394 capacity = (sector_t)-1; 395 } 396 397 nblocks = DIV_ROUND_UP_ULL(capacity, queue_logical_block_size(q) >> 9); 398 399 string_get_size(nblocks, queue_logical_block_size(q), 400 STRING_UNITS_2, cap_str_2, sizeof(cap_str_2)); 401 string_get_size(nblocks, queue_logical_block_size(q), 402 STRING_UNITS_10, cap_str_10, sizeof(cap_str_10)); 403 404 dev_notice(&vdev->dev, 405 "new size: %llu %d-byte logical blocks (%s/%s)\n", 406 nblocks, 407 queue_logical_block_size(q), 408 cap_str_10, 409 cap_str_2); 410 411 set_capacity(vblk->disk, capacity); 412 revalidate_disk(vblk->disk); 413 kobject_uevent_env(&disk_to_dev(vblk->disk)->kobj, KOBJ_CHANGE, envp); 414 } 415 416 static void virtblk_config_changed(struct virtio_device *vdev) 417 { 418 struct virtio_blk *vblk = vdev->priv; 419 420 queue_work(virtblk_wq, &vblk->config_work); 421 } 422 423 static int init_vq(struct virtio_blk *vblk) 424 { 425 int err; 426 int i; 427 vq_callback_t **callbacks; 428 const char **names; 429 struct virtqueue **vqs; 430 unsigned short num_vqs; 431 struct virtio_device *vdev = vblk->vdev; 432 struct irq_affinity desc = { 0, }; 433 434 err = virtio_cread_feature(vdev, VIRTIO_BLK_F_MQ, 435 struct virtio_blk_config, num_queues, 436 &num_vqs); 437 if (err) 438 num_vqs = 1; 439 440 vblk->vqs = kmalloc_array(num_vqs, sizeof(*vblk->vqs), GFP_KERNEL); 441 if (!vblk->vqs) 442 return -ENOMEM; 443 444 names = kmalloc_array(num_vqs, sizeof(*names), GFP_KERNEL); 445 callbacks = kmalloc_array(num_vqs, sizeof(*callbacks), GFP_KERNEL); 446 vqs = kmalloc_array(num_vqs, sizeof(*vqs), GFP_KERNEL); 447 if (!names || !callbacks || !vqs) { 448 err = -ENOMEM; 449 goto out; 450 } 451 452 for (i = 0; i < num_vqs; i++) { 453 callbacks[i] = virtblk_done; 454 snprintf(vblk->vqs[i].name, VQ_NAME_LEN, "req.%d", i); 455 names[i] = vblk->vqs[i].name; 456 } 457 458 /* Discover virtqueues and write information to configuration. */ 459 err = virtio_find_vqs(vdev, num_vqs, vqs, callbacks, names, &desc); 460 if (err) 461 goto out; 462 463 for (i = 0; i < num_vqs; i++) { 464 spin_lock_init(&vblk->vqs[i].lock); 465 vblk->vqs[i].vq = vqs[i]; 466 } 467 vblk->num_vqs = num_vqs; 468 469 out: 470 kfree(vqs); 471 kfree(callbacks); 472 kfree(names); 473 if (err) 474 kfree(vblk->vqs); 475 return err; 476 } 477 478 /* 479 * Legacy naming scheme used for virtio devices. We are stuck with it for 480 * virtio blk but don't ever use it for any new driver. 481 */ 482 static int virtblk_name_format(char *prefix, int index, char *buf, int buflen) 483 { 484 const int base = 'z' - 'a' + 1; 485 char *begin = buf + strlen(prefix); 486 char *end = buf + buflen; 487 char *p; 488 int unit; 489 490 p = end - 1; 491 *p = '\0'; 492 unit = base; 493 do { 494 if (p == begin) 495 return -EINVAL; 496 *--p = 'a' + (index % unit); 497 index = (index / unit) - 1; 498 } while (index >= 0); 499 500 memmove(begin, p, end - p); 501 memcpy(buf, prefix, strlen(prefix)); 502 503 return 0; 504 } 505 506 static int virtblk_get_cache_mode(struct virtio_device *vdev) 507 { 508 u8 writeback; 509 int err; 510 511 err = virtio_cread_feature(vdev, VIRTIO_BLK_F_CONFIG_WCE, 512 struct virtio_blk_config, wce, 513 &writeback); 514 515 /* 516 * If WCE is not configurable and flush is not available, 517 * assume no writeback cache is in use. 518 */ 519 if (err) 520 writeback = virtio_has_feature(vdev, VIRTIO_BLK_F_FLUSH); 521 522 return writeback; 523 } 524 525 static void virtblk_update_cache_mode(struct virtio_device *vdev) 526 { 527 u8 writeback = virtblk_get_cache_mode(vdev); 528 struct virtio_blk *vblk = vdev->priv; 529 530 blk_queue_write_cache(vblk->disk->queue, writeback, false); 531 revalidate_disk(vblk->disk); 532 } 533 534 static const char *const virtblk_cache_types[] = { 535 "write through", "write back" 536 }; 537 538 static ssize_t 539 virtblk_cache_type_store(struct device *dev, struct device_attribute *attr, 540 const char *buf, size_t count) 541 { 542 struct gendisk *disk = dev_to_disk(dev); 543 struct virtio_blk *vblk = disk->private_data; 544 struct virtio_device *vdev = vblk->vdev; 545 int i; 546 547 BUG_ON(!virtio_has_feature(vblk->vdev, VIRTIO_BLK_F_CONFIG_WCE)); 548 i = sysfs_match_string(virtblk_cache_types, buf); 549 if (i < 0) 550 return i; 551 552 virtio_cwrite8(vdev, offsetof(struct virtio_blk_config, wce), i); 553 virtblk_update_cache_mode(vdev); 554 return count; 555 } 556 557 static ssize_t 558 virtblk_cache_type_show(struct device *dev, struct device_attribute *attr, 559 char *buf) 560 { 561 struct gendisk *disk = dev_to_disk(dev); 562 struct virtio_blk *vblk = disk->private_data; 563 u8 writeback = virtblk_get_cache_mode(vblk->vdev); 564 565 BUG_ON(writeback >= ARRAY_SIZE(virtblk_cache_types)); 566 return snprintf(buf, 40, "%s\n", virtblk_cache_types[writeback]); 567 } 568 569 static const struct device_attribute dev_attr_cache_type_ro = 570 __ATTR(cache_type, S_IRUGO, 571 virtblk_cache_type_show, NULL); 572 static const struct device_attribute dev_attr_cache_type_rw = 573 __ATTR(cache_type, S_IRUGO|S_IWUSR, 574 virtblk_cache_type_show, virtblk_cache_type_store); 575 576 static int virtblk_init_request(struct blk_mq_tag_set *set, struct request *rq, 577 unsigned int hctx_idx, unsigned int numa_node) 578 { 579 struct virtio_blk *vblk = set->driver_data; 580 struct virtblk_req *vbr = blk_mq_rq_to_pdu(rq); 581 582 #ifdef CONFIG_VIRTIO_BLK_SCSI 583 vbr->sreq.sense = vbr->sense; 584 #endif 585 sg_init_table(vbr->sg, vblk->sg_elems); 586 return 0; 587 } 588 589 static int virtblk_map_queues(struct blk_mq_tag_set *set) 590 { 591 struct virtio_blk *vblk = set->driver_data; 592 593 return blk_mq_virtio_map_queues(set, vblk->vdev, 0); 594 } 595 596 static const struct blk_mq_ops virtio_mq_ops = { 597 .queue_rq = virtio_queue_rq, 598 .complete = virtblk_request_done, 599 .init_request = virtblk_init_request, 600 .map_queues = virtblk_map_queues, 601 }; 602 603 static unsigned int virtblk_queue_depth; 604 module_param_named(queue_depth, virtblk_queue_depth, uint, 0444); 605 606 static int virtblk_probe(struct virtio_device *vdev) 607 { 608 struct virtio_blk *vblk; 609 struct request_queue *q; 610 int err, index; 611 612 u64 cap; 613 u32 v, blk_size, sg_elems, opt_io_size; 614 u16 min_io_size; 615 u8 physical_block_exp, alignment_offset; 616 617 if (!vdev->config->get) { 618 dev_err(&vdev->dev, "%s failure: config access disabled\n", 619 __func__); 620 return -EINVAL; 621 } 622 623 err = ida_simple_get(&vd_index_ida, 0, minor_to_index(1 << MINORBITS), 624 GFP_KERNEL); 625 if (err < 0) 626 goto out; 627 index = err; 628 629 /* We need to know how many segments before we allocate. */ 630 err = virtio_cread_feature(vdev, VIRTIO_BLK_F_SEG_MAX, 631 struct virtio_blk_config, seg_max, 632 &sg_elems); 633 634 /* We need at least one SG element, whatever they say. */ 635 if (err || !sg_elems) 636 sg_elems = 1; 637 638 /* We need an extra sg elements at head and tail. */ 639 sg_elems += 2; 640 vdev->priv = vblk = kmalloc(sizeof(*vblk), GFP_KERNEL); 641 if (!vblk) { 642 err = -ENOMEM; 643 goto out_free_index; 644 } 645 646 vblk->vdev = vdev; 647 vblk->sg_elems = sg_elems; 648 649 INIT_WORK(&vblk->config_work, virtblk_config_changed_work); 650 651 err = init_vq(vblk); 652 if (err) 653 goto out_free_vblk; 654 655 /* FIXME: How many partitions? How long is a piece of string? */ 656 vblk->disk = alloc_disk(1 << PART_BITS); 657 if (!vblk->disk) { 658 err = -ENOMEM; 659 goto out_free_vq; 660 } 661 662 /* Default queue sizing is to fill the ring. */ 663 if (!virtblk_queue_depth) { 664 virtblk_queue_depth = vblk->vqs[0].vq->num_free; 665 /* ... but without indirect descs, we use 2 descs per req */ 666 if (!virtio_has_feature(vdev, VIRTIO_RING_F_INDIRECT_DESC)) 667 virtblk_queue_depth /= 2; 668 } 669 670 memset(&vblk->tag_set, 0, sizeof(vblk->tag_set)); 671 vblk->tag_set.ops = &virtio_mq_ops; 672 vblk->tag_set.queue_depth = virtblk_queue_depth; 673 vblk->tag_set.numa_node = NUMA_NO_NODE; 674 vblk->tag_set.flags = BLK_MQ_F_SHOULD_MERGE; 675 vblk->tag_set.cmd_size = 676 sizeof(struct virtblk_req) + 677 sizeof(struct scatterlist) * sg_elems; 678 vblk->tag_set.driver_data = vblk; 679 vblk->tag_set.nr_hw_queues = vblk->num_vqs; 680 681 err = blk_mq_alloc_tag_set(&vblk->tag_set); 682 if (err) 683 goto out_put_disk; 684 685 q = blk_mq_init_queue(&vblk->tag_set); 686 if (IS_ERR(q)) { 687 err = -ENOMEM; 688 goto out_free_tags; 689 } 690 vblk->disk->queue = q; 691 692 q->queuedata = vblk; 693 694 virtblk_name_format("vd", index, vblk->disk->disk_name, DISK_NAME_LEN); 695 696 vblk->disk->major = major; 697 vblk->disk->first_minor = index_to_minor(index); 698 vblk->disk->private_data = vblk; 699 vblk->disk->fops = &virtblk_fops; 700 vblk->disk->flags |= GENHD_FL_EXT_DEVT; 701 vblk->index = index; 702 703 /* configure queue flush support */ 704 virtblk_update_cache_mode(vdev); 705 706 /* If disk is read-only in the host, the guest should obey */ 707 if (virtio_has_feature(vdev, VIRTIO_BLK_F_RO)) 708 set_disk_ro(vblk->disk, 1); 709 710 /* Host must always specify the capacity. */ 711 virtio_cread(vdev, struct virtio_blk_config, capacity, &cap); 712 713 /* If capacity is too big, truncate with warning. */ 714 if ((sector_t)cap != cap) { 715 dev_warn(&vdev->dev, "Capacity %llu too large: truncating\n", 716 (unsigned long long)cap); 717 cap = (sector_t)-1; 718 } 719 set_capacity(vblk->disk, cap); 720 721 /* We can handle whatever the host told us to handle. */ 722 blk_queue_max_segments(q, vblk->sg_elems-2); 723 724 /* No real sector limit. */ 725 blk_queue_max_hw_sectors(q, -1U); 726 727 /* Host can optionally specify maximum segment size and number of 728 * segments. */ 729 err = virtio_cread_feature(vdev, VIRTIO_BLK_F_SIZE_MAX, 730 struct virtio_blk_config, size_max, &v); 731 if (!err) 732 blk_queue_max_segment_size(q, v); 733 else 734 blk_queue_max_segment_size(q, -1U); 735 736 /* Host can optionally specify the block size of the device */ 737 err = virtio_cread_feature(vdev, VIRTIO_BLK_F_BLK_SIZE, 738 struct virtio_blk_config, blk_size, 739 &blk_size); 740 if (!err) 741 blk_queue_logical_block_size(q, blk_size); 742 else 743 blk_size = queue_logical_block_size(q); 744 745 /* Use topology information if available */ 746 err = virtio_cread_feature(vdev, VIRTIO_BLK_F_TOPOLOGY, 747 struct virtio_blk_config, physical_block_exp, 748 &physical_block_exp); 749 if (!err && physical_block_exp) 750 blk_queue_physical_block_size(q, 751 blk_size * (1 << physical_block_exp)); 752 753 err = virtio_cread_feature(vdev, VIRTIO_BLK_F_TOPOLOGY, 754 struct virtio_blk_config, alignment_offset, 755 &alignment_offset); 756 if (!err && alignment_offset) 757 blk_queue_alignment_offset(q, blk_size * alignment_offset); 758 759 err = virtio_cread_feature(vdev, VIRTIO_BLK_F_TOPOLOGY, 760 struct virtio_blk_config, min_io_size, 761 &min_io_size); 762 if (!err && min_io_size) 763 blk_queue_io_min(q, blk_size * min_io_size); 764 765 err = virtio_cread_feature(vdev, VIRTIO_BLK_F_TOPOLOGY, 766 struct virtio_blk_config, opt_io_size, 767 &opt_io_size); 768 if (!err && opt_io_size) 769 blk_queue_io_opt(q, blk_size * opt_io_size); 770 771 virtio_device_ready(vdev); 772 773 device_add_disk(&vdev->dev, vblk->disk); 774 err = device_create_file(disk_to_dev(vblk->disk), &dev_attr_serial); 775 if (err) 776 goto out_del_disk; 777 778 if (virtio_has_feature(vdev, VIRTIO_BLK_F_CONFIG_WCE)) 779 err = device_create_file(disk_to_dev(vblk->disk), 780 &dev_attr_cache_type_rw); 781 else 782 err = device_create_file(disk_to_dev(vblk->disk), 783 &dev_attr_cache_type_ro); 784 if (err) 785 goto out_del_disk; 786 return 0; 787 788 out_del_disk: 789 del_gendisk(vblk->disk); 790 blk_cleanup_queue(vblk->disk->queue); 791 out_free_tags: 792 blk_mq_free_tag_set(&vblk->tag_set); 793 out_put_disk: 794 put_disk(vblk->disk); 795 out_free_vq: 796 vdev->config->del_vqs(vdev); 797 out_free_vblk: 798 kfree(vblk); 799 out_free_index: 800 ida_simple_remove(&vd_index_ida, index); 801 out: 802 return err; 803 } 804 805 static void virtblk_remove(struct virtio_device *vdev) 806 { 807 struct virtio_blk *vblk = vdev->priv; 808 int index = vblk->index; 809 int refc; 810 811 /* Make sure no work handler is accessing the device. */ 812 flush_work(&vblk->config_work); 813 814 del_gendisk(vblk->disk); 815 blk_cleanup_queue(vblk->disk->queue); 816 817 blk_mq_free_tag_set(&vblk->tag_set); 818 819 /* Stop all the virtqueues. */ 820 vdev->config->reset(vdev); 821 822 refc = kref_read(&disk_to_dev(vblk->disk)->kobj.kref); 823 put_disk(vblk->disk); 824 vdev->config->del_vqs(vdev); 825 kfree(vblk->vqs); 826 kfree(vblk); 827 828 /* Only free device id if we don't have any users */ 829 if (refc == 1) 830 ida_simple_remove(&vd_index_ida, index); 831 } 832 833 #ifdef CONFIG_PM_SLEEP 834 static int virtblk_freeze(struct virtio_device *vdev) 835 { 836 struct virtio_blk *vblk = vdev->priv; 837 838 /* Ensure we don't receive any more interrupts */ 839 vdev->config->reset(vdev); 840 841 /* Make sure no work handler is accessing the device. */ 842 flush_work(&vblk->config_work); 843 844 blk_mq_quiesce_queue(vblk->disk->queue); 845 846 vdev->config->del_vqs(vdev); 847 return 0; 848 } 849 850 static int virtblk_restore(struct virtio_device *vdev) 851 { 852 struct virtio_blk *vblk = vdev->priv; 853 int ret; 854 855 ret = init_vq(vdev->priv); 856 if (ret) 857 return ret; 858 859 virtio_device_ready(vdev); 860 861 blk_mq_unquiesce_queue(vblk->disk->queue); 862 return 0; 863 } 864 #endif 865 866 static const struct virtio_device_id id_table[] = { 867 { VIRTIO_ID_BLOCK, VIRTIO_DEV_ANY_ID }, 868 { 0 }, 869 }; 870 871 static unsigned int features_legacy[] = { 872 VIRTIO_BLK_F_SEG_MAX, VIRTIO_BLK_F_SIZE_MAX, VIRTIO_BLK_F_GEOMETRY, 873 VIRTIO_BLK_F_RO, VIRTIO_BLK_F_BLK_SIZE, 874 #ifdef CONFIG_VIRTIO_BLK_SCSI 875 VIRTIO_BLK_F_SCSI, 876 #endif 877 VIRTIO_BLK_F_FLUSH, VIRTIO_BLK_F_TOPOLOGY, VIRTIO_BLK_F_CONFIG_WCE, 878 VIRTIO_BLK_F_MQ, 879 } 880 ; 881 static unsigned int features[] = { 882 VIRTIO_BLK_F_SEG_MAX, VIRTIO_BLK_F_SIZE_MAX, VIRTIO_BLK_F_GEOMETRY, 883 VIRTIO_BLK_F_RO, VIRTIO_BLK_F_BLK_SIZE, 884 VIRTIO_BLK_F_FLUSH, VIRTIO_BLK_F_TOPOLOGY, VIRTIO_BLK_F_CONFIG_WCE, 885 VIRTIO_BLK_F_MQ, 886 }; 887 888 static struct virtio_driver virtio_blk = { 889 .feature_table = features, 890 .feature_table_size = ARRAY_SIZE(features), 891 .feature_table_legacy = features_legacy, 892 .feature_table_size_legacy = ARRAY_SIZE(features_legacy), 893 .driver.name = KBUILD_MODNAME, 894 .driver.owner = THIS_MODULE, 895 .id_table = id_table, 896 .probe = virtblk_probe, 897 .remove = virtblk_remove, 898 .config_changed = virtblk_config_changed, 899 #ifdef CONFIG_PM_SLEEP 900 .freeze = virtblk_freeze, 901 .restore = virtblk_restore, 902 #endif 903 }; 904 905 static int __init init(void) 906 { 907 int error; 908 909 virtblk_wq = alloc_workqueue("virtio-blk", 0, 0); 910 if (!virtblk_wq) 911 return -ENOMEM; 912 913 major = register_blkdev(0, "virtblk"); 914 if (major < 0) { 915 error = major; 916 goto out_destroy_workqueue; 917 } 918 919 error = register_virtio_driver(&virtio_blk); 920 if (error) 921 goto out_unregister_blkdev; 922 return 0; 923 924 out_unregister_blkdev: 925 unregister_blkdev(major, "virtblk"); 926 out_destroy_workqueue: 927 destroy_workqueue(virtblk_wq); 928 return error; 929 } 930 931 static void __exit fini(void) 932 { 933 unregister_virtio_driver(&virtio_blk); 934 unregister_blkdev(major, "virtblk"); 935 destroy_workqueue(virtblk_wq); 936 } 937 module_init(init); 938 module_exit(fini); 939 940 MODULE_DEVICE_TABLE(virtio, id_table); 941 MODULE_DESCRIPTION("Virtio block driver"); 942 MODULE_LICENSE("GPL"); 943