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 20static int major; 21static DEFINE_IDA(vd_index_ida); 22 23static struct workqueue_struct *virtblk_wq; 24 25struct virtio_blk_vq { 26 struct virtqueue *vq; 27 spinlock_t lock; 28 char name[VQ_NAME_LEN]; 29} ____cacheline_aligned_in_smp; 30 31struct 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 54struct 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 62static 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 74static 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 117static 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 134static 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 160static 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->cmd_flags & REQ_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 */ 236static 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_DRV_PRIV; 255 err = blk_execute_rq(vblk->disk->queue, vblk->disk, req, false); 256 blk_put_request(req); 257 258 return err; 259} 260 261static 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 */ 278static 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 299static const struct block_device_operations virtblk_fops = { 300 .ioctl = virtblk_ioctl, 301 .owner = THIS_MODULE, 302 .getgeo = virtblk_getgeo, 303}; 304 305static int index_to_minor(int index) 306{ 307 return index << PART_BITS; 308} 309 310static int minor_to_index(int minor) 311{ 312 return minor >> PART_BITS; 313} 314 315static 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 335static DEVICE_ATTR(serial, S_IRUGO, virtblk_serial_show, NULL); 336 337static void virtblk_config_changed_work(struct work_struct *work) 338{ 339 struct virtio_blk *vblk = 340 container_of(work, struct virtio_blk, config_work); 341 struct virtio_device *vdev = vblk->vdev; 342 struct request_queue *q = vblk->disk->queue; 343 char cap_str_2[10], cap_str_10[10]; 344 char *envp[] = { "RESIZE=1", NULL }; 345 u64 capacity; 346 347 /* Host must always specify the capacity. */ 348 virtio_cread(vdev, struct virtio_blk_config, capacity, &capacity); 349 350 /* If capacity is too big, truncate with warning. */ 351 if ((sector_t)capacity != capacity) { 352 dev_warn(&vdev->dev, "Capacity %llu too large: truncating\n", 353 (unsigned long long)capacity); 354 capacity = (sector_t)-1; 355 } 356 357 string_get_size(capacity, queue_logical_block_size(q), 358 STRING_UNITS_2, cap_str_2, sizeof(cap_str_2)); 359 string_get_size(capacity, queue_logical_block_size(q), 360 STRING_UNITS_10, cap_str_10, sizeof(cap_str_10)); 361 362 dev_notice(&vdev->dev, 363 "new size: %llu %d-byte logical blocks (%s/%s)\n", 364 (unsigned long long)capacity, 365 queue_logical_block_size(q), 366 cap_str_10, cap_str_2); 367 368 set_capacity(vblk->disk, capacity); 369 revalidate_disk(vblk->disk); 370 kobject_uevent_env(&disk_to_dev(vblk->disk)->kobj, KOBJ_CHANGE, envp); 371} 372 373static void virtblk_config_changed(struct virtio_device *vdev) 374{ 375 struct virtio_blk *vblk = vdev->priv; 376 377 queue_work(virtblk_wq, &vblk->config_work); 378} 379 380static int init_vq(struct virtio_blk *vblk) 381{ 382 int err = 0; 383 int i; 384 vq_callback_t **callbacks; 385 const char **names; 386 struct virtqueue **vqs; 387 unsigned short num_vqs; 388 struct virtio_device *vdev = vblk->vdev; 389 390 err = virtio_cread_feature(vdev, VIRTIO_BLK_F_MQ, 391 struct virtio_blk_config, num_queues, 392 &num_vqs); 393 if (err) 394 num_vqs = 1; 395 396 vblk->vqs = kmalloc(sizeof(*vblk->vqs) * num_vqs, GFP_KERNEL); 397 if (!vblk->vqs) { 398 err = -ENOMEM; 399 goto out; 400 } 401 402 names = kmalloc(sizeof(*names) * num_vqs, GFP_KERNEL); 403 if (!names) 404 goto err_names; 405 406 callbacks = kmalloc(sizeof(*callbacks) * num_vqs, GFP_KERNEL); 407 if (!callbacks) 408 goto err_callbacks; 409 410 vqs = kmalloc(sizeof(*vqs) * num_vqs, GFP_KERNEL); 411 if (!vqs) 412 goto err_vqs; 413 414 for (i = 0; i < num_vqs; i++) { 415 callbacks[i] = virtblk_done; 416 snprintf(vblk->vqs[i].name, VQ_NAME_LEN, "req.%d", i); 417 names[i] = vblk->vqs[i].name; 418 } 419 420 /* Discover virtqueues and write information to configuration. */ 421 err = vdev->config->find_vqs(vdev, num_vqs, vqs, callbacks, names); 422 if (err) 423 goto err_find_vqs; 424 425 for (i = 0; i < num_vqs; i++) { 426 spin_lock_init(&vblk->vqs[i].lock); 427 vblk->vqs[i].vq = vqs[i]; 428 } 429 vblk->num_vqs = num_vqs; 430 431 err_find_vqs: 432 kfree(vqs); 433 err_vqs: 434 kfree(callbacks); 435 err_callbacks: 436 kfree(names); 437 err_names: 438 if (err) 439 kfree(vblk->vqs); 440 out: 441 return err; 442} 443 444/* 445 * Legacy naming scheme used for virtio devices. We are stuck with it for 446 * virtio blk but don't ever use it for any new driver. 447 */ 448static int virtblk_name_format(char *prefix, int index, char *buf, int buflen) 449{ 450 const int base = 'z' - 'a' + 1; 451 char *begin = buf + strlen(prefix); 452 char *end = buf + buflen; 453 char *p; 454 int unit; 455 456 p = end - 1; 457 *p = '\0'; 458 unit = base; 459 do { 460 if (p == begin) 461 return -EINVAL; 462 *--p = 'a' + (index % unit); 463 index = (index / unit) - 1; 464 } while (index >= 0); 465 466 memmove(begin, p, end - p); 467 memcpy(buf, prefix, strlen(prefix)); 468 469 return 0; 470} 471 472static int virtblk_get_cache_mode(struct virtio_device *vdev) 473{ 474 u8 writeback; 475 int err; 476 477 err = virtio_cread_feature(vdev, VIRTIO_BLK_F_CONFIG_WCE, 478 struct virtio_blk_config, wce, 479 &writeback); 480 if (err) 481 writeback = virtio_has_feature(vdev, VIRTIO_BLK_F_WCE); 482 483 return writeback; 484} 485 486static void virtblk_update_cache_mode(struct virtio_device *vdev) 487{ 488 u8 writeback = virtblk_get_cache_mode(vdev); 489 struct virtio_blk *vblk = vdev->priv; 490 491 if (writeback) 492 blk_queue_flush(vblk->disk->queue, REQ_FLUSH); 493 else 494 blk_queue_flush(vblk->disk->queue, 0); 495 496 revalidate_disk(vblk->disk); 497} 498 499static const char *const virtblk_cache_types[] = { 500 "write through", "write back" 501}; 502 503static ssize_t 504virtblk_cache_type_store(struct device *dev, struct device_attribute *attr, 505 const char *buf, size_t count) 506{ 507 struct gendisk *disk = dev_to_disk(dev); 508 struct virtio_blk *vblk = disk->private_data; 509 struct virtio_device *vdev = vblk->vdev; 510 int i; 511 512 BUG_ON(!virtio_has_feature(vblk->vdev, VIRTIO_BLK_F_CONFIG_WCE)); 513 for (i = ARRAY_SIZE(virtblk_cache_types); --i >= 0; ) 514 if (sysfs_streq(buf, virtblk_cache_types[i])) 515 break; 516 517 if (i < 0) 518 return -EINVAL; 519 520 virtio_cwrite8(vdev, offsetof(struct virtio_blk_config, wce), i); 521 virtblk_update_cache_mode(vdev); 522 return count; 523} 524 525static ssize_t 526virtblk_cache_type_show(struct device *dev, struct device_attribute *attr, 527 char *buf) 528{ 529 struct gendisk *disk = dev_to_disk(dev); 530 struct virtio_blk *vblk = disk->private_data; 531 u8 writeback = virtblk_get_cache_mode(vblk->vdev); 532 533 BUG_ON(writeback >= ARRAY_SIZE(virtblk_cache_types)); 534 return snprintf(buf, 40, "%s\n", virtblk_cache_types[writeback]); 535} 536 537static const struct device_attribute dev_attr_cache_type_ro = 538 __ATTR(cache_type, S_IRUGO, 539 virtblk_cache_type_show, NULL); 540static const struct device_attribute dev_attr_cache_type_rw = 541 __ATTR(cache_type, S_IRUGO|S_IWUSR, 542 virtblk_cache_type_show, virtblk_cache_type_store); 543 544static int virtblk_init_request(void *data, struct request *rq, 545 unsigned int hctx_idx, unsigned int request_idx, 546 unsigned int numa_node) 547{ 548 struct virtio_blk *vblk = data; 549 struct virtblk_req *vbr = blk_mq_rq_to_pdu(rq); 550 551 sg_init_table(vbr->sg, vblk->sg_elems); 552 return 0; 553} 554 555static struct blk_mq_ops virtio_mq_ops = { 556 .queue_rq = virtio_queue_rq, 557 .map_queue = blk_mq_map_queue, 558 .complete = virtblk_request_done, 559 .init_request = virtblk_init_request, 560}; 561 562static unsigned int virtblk_queue_depth; 563module_param_named(queue_depth, virtblk_queue_depth, uint, 0444); 564 565static int virtblk_probe(struct virtio_device *vdev) 566{ 567 struct virtio_blk *vblk; 568 struct request_queue *q; 569 int err, index; 570 571 u64 cap; 572 u32 v, blk_size, sg_elems, opt_io_size; 573 u16 min_io_size; 574 u8 physical_block_exp, alignment_offset; 575 576 if (!vdev->config->get) { 577 dev_err(&vdev->dev, "%s failure: config access disabled\n", 578 __func__); 579 return -EINVAL; 580 } 581 582 err = ida_simple_get(&vd_index_ida, 0, minor_to_index(1 << MINORBITS), 583 GFP_KERNEL); 584 if (err < 0) 585 goto out; 586 index = err; 587 588 /* We need to know how many segments before we allocate. */ 589 err = virtio_cread_feature(vdev, VIRTIO_BLK_F_SEG_MAX, 590 struct virtio_blk_config, seg_max, 591 &sg_elems); 592 593 /* We need at least one SG element, whatever they say. */ 594 if (err || !sg_elems) 595 sg_elems = 1; 596 597 /* We need an extra sg elements at head and tail. */ 598 sg_elems += 2; 599 vdev->priv = vblk = kmalloc(sizeof(*vblk), GFP_KERNEL); 600 if (!vblk) { 601 err = -ENOMEM; 602 goto out_free_index; 603 } 604 605 vblk->vdev = vdev; 606 vblk->sg_elems = sg_elems; 607 608 INIT_WORK(&vblk->config_work, virtblk_config_changed_work); 609 610 err = init_vq(vblk); 611 if (err) 612 goto out_free_vblk; 613 614 /* FIXME: How many partitions? How long is a piece of string? */ 615 vblk->disk = alloc_disk(1 << PART_BITS); 616 if (!vblk->disk) { 617 err = -ENOMEM; 618 goto out_free_vq; 619 } 620 621 /* Default queue sizing is to fill the ring. */ 622 if (!virtblk_queue_depth) { 623 virtblk_queue_depth = vblk->vqs[0].vq->num_free; 624 /* ... but without indirect descs, we use 2 descs per req */ 625 if (!virtio_has_feature(vdev, VIRTIO_RING_F_INDIRECT_DESC)) 626 virtblk_queue_depth /= 2; 627 } 628 629 memset(&vblk->tag_set, 0, sizeof(vblk->tag_set)); 630 vblk->tag_set.ops = &virtio_mq_ops; 631 vblk->tag_set.queue_depth = virtblk_queue_depth; 632 vblk->tag_set.numa_node = NUMA_NO_NODE; 633 vblk->tag_set.flags = BLK_MQ_F_SHOULD_MERGE; 634 vblk->tag_set.cmd_size = 635 sizeof(struct virtblk_req) + 636 sizeof(struct scatterlist) * sg_elems; 637 vblk->tag_set.driver_data = vblk; 638 vblk->tag_set.nr_hw_queues = vblk->num_vqs; 639 640 err = blk_mq_alloc_tag_set(&vblk->tag_set); 641 if (err) 642 goto out_put_disk; 643 644 q = vblk->disk->queue = blk_mq_init_queue(&vblk->tag_set); 645 if (IS_ERR(q)) { 646 err = -ENOMEM; 647 goto out_free_tags; 648 } 649 650 q->queuedata = vblk; 651 652 virtblk_name_format("vd", index, vblk->disk->disk_name, DISK_NAME_LEN); 653 654 vblk->disk->major = major; 655 vblk->disk->first_minor = index_to_minor(index); 656 vblk->disk->private_data = vblk; 657 vblk->disk->fops = &virtblk_fops; 658 vblk->disk->driverfs_dev = &vdev->dev; 659 vblk->disk->flags |= GENHD_FL_EXT_DEVT; 660 vblk->index = index; 661 662 /* configure queue flush support */ 663 virtblk_update_cache_mode(vdev); 664 665 /* If disk is read-only in the host, the guest should obey */ 666 if (virtio_has_feature(vdev, VIRTIO_BLK_F_RO)) 667 set_disk_ro(vblk->disk, 1); 668 669 /* Host must always specify the capacity. */ 670 virtio_cread(vdev, struct virtio_blk_config, capacity, &cap); 671 672 /* If capacity is too big, truncate with warning. */ 673 if ((sector_t)cap != cap) { 674 dev_warn(&vdev->dev, "Capacity %llu too large: truncating\n", 675 (unsigned long long)cap); 676 cap = (sector_t)-1; 677 } 678 set_capacity(vblk->disk, cap); 679 680 /* We can handle whatever the host told us to handle. */ 681 blk_queue_max_segments(q, vblk->sg_elems-2); 682 683 /* No need to bounce any requests */ 684 blk_queue_bounce_limit(q, BLK_BOUNCE_ANY); 685 686 /* No real sector limit. */ 687 blk_queue_max_hw_sectors(q, -1U); 688 689 /* Host can optionally specify maximum segment size and number of 690 * segments. */ 691 err = virtio_cread_feature(vdev, VIRTIO_BLK_F_SIZE_MAX, 692 struct virtio_blk_config, size_max, &v); 693 if (!err) 694 blk_queue_max_segment_size(q, v); 695 else 696 blk_queue_max_segment_size(q, -1U); 697 698 /* Host can optionally specify the block size of the device */ 699 err = virtio_cread_feature(vdev, VIRTIO_BLK_F_BLK_SIZE, 700 struct virtio_blk_config, blk_size, 701 &blk_size); 702 if (!err) 703 blk_queue_logical_block_size(q, blk_size); 704 else 705 blk_size = queue_logical_block_size(q); 706 707 /* Use topology information if available */ 708 err = virtio_cread_feature(vdev, VIRTIO_BLK_F_TOPOLOGY, 709 struct virtio_blk_config, physical_block_exp, 710 &physical_block_exp); 711 if (!err && physical_block_exp) 712 blk_queue_physical_block_size(q, 713 blk_size * (1 << physical_block_exp)); 714 715 err = virtio_cread_feature(vdev, VIRTIO_BLK_F_TOPOLOGY, 716 struct virtio_blk_config, alignment_offset, 717 &alignment_offset); 718 if (!err && alignment_offset) 719 blk_queue_alignment_offset(q, blk_size * alignment_offset); 720 721 err = virtio_cread_feature(vdev, VIRTIO_BLK_F_TOPOLOGY, 722 struct virtio_blk_config, min_io_size, 723 &min_io_size); 724 if (!err && min_io_size) 725 blk_queue_io_min(q, blk_size * min_io_size); 726 727 err = virtio_cread_feature(vdev, VIRTIO_BLK_F_TOPOLOGY, 728 struct virtio_blk_config, opt_io_size, 729 &opt_io_size); 730 if (!err && opt_io_size) 731 blk_queue_io_opt(q, blk_size * opt_io_size); 732 733 virtio_device_ready(vdev); 734 735 add_disk(vblk->disk); 736 err = device_create_file(disk_to_dev(vblk->disk), &dev_attr_serial); 737 if (err) 738 goto out_del_disk; 739 740 if (virtio_has_feature(vdev, VIRTIO_BLK_F_CONFIG_WCE)) 741 err = device_create_file(disk_to_dev(vblk->disk), 742 &dev_attr_cache_type_rw); 743 else 744 err = device_create_file(disk_to_dev(vblk->disk), 745 &dev_attr_cache_type_ro); 746 if (err) 747 goto out_del_disk; 748 return 0; 749 750out_del_disk: 751 del_gendisk(vblk->disk); 752 blk_cleanup_queue(vblk->disk->queue); 753out_free_tags: 754 blk_mq_free_tag_set(&vblk->tag_set); 755out_put_disk: 756 put_disk(vblk->disk); 757out_free_vq: 758 vdev->config->del_vqs(vdev); 759out_free_vblk: 760 kfree(vblk); 761out_free_index: 762 ida_simple_remove(&vd_index_ida, index); 763out: 764 return err; 765} 766 767static void virtblk_remove(struct virtio_device *vdev) 768{ 769 struct virtio_blk *vblk = vdev->priv; 770 int index = vblk->index; 771 int refc; 772 773 /* Make sure no work handler is accessing the device. */ 774 flush_work(&vblk->config_work); 775 776 del_gendisk(vblk->disk); 777 blk_cleanup_queue(vblk->disk->queue); 778 779 blk_mq_free_tag_set(&vblk->tag_set); 780 781 /* Stop all the virtqueues. */ 782 vdev->config->reset(vdev); 783 784 refc = atomic_read(&disk_to_dev(vblk->disk)->kobj.kref.refcount); 785 put_disk(vblk->disk); 786 vdev->config->del_vqs(vdev); 787 kfree(vblk->vqs); 788 kfree(vblk); 789 790 /* Only free device id if we don't have any users */ 791 if (refc == 1) 792 ida_simple_remove(&vd_index_ida, index); 793} 794 795#ifdef CONFIG_PM_SLEEP 796static int virtblk_freeze(struct virtio_device *vdev) 797{ 798 struct virtio_blk *vblk = vdev->priv; 799 800 /* Ensure we don't receive any more interrupts */ 801 vdev->config->reset(vdev); 802 803 /* Make sure no work handler is accessing the device. */ 804 flush_work(&vblk->config_work); 805 806 blk_mq_stop_hw_queues(vblk->disk->queue); 807 808 vdev->config->del_vqs(vdev); 809 return 0; 810} 811 812static int virtblk_restore(struct virtio_device *vdev) 813{ 814 struct virtio_blk *vblk = vdev->priv; 815 int ret; 816 817 ret = init_vq(vdev->priv); 818 if (ret) 819 return ret; 820 821 virtio_device_ready(vdev); 822 823 blk_mq_start_stopped_hw_queues(vblk->disk->queue, true); 824 return 0; 825} 826#endif 827 828static const struct virtio_device_id id_table[] = { 829 { VIRTIO_ID_BLOCK, VIRTIO_DEV_ANY_ID }, 830 { 0 }, 831}; 832 833static unsigned int features_legacy[] = { 834 VIRTIO_BLK_F_SEG_MAX, VIRTIO_BLK_F_SIZE_MAX, VIRTIO_BLK_F_GEOMETRY, 835 VIRTIO_BLK_F_RO, VIRTIO_BLK_F_BLK_SIZE, VIRTIO_BLK_F_SCSI, 836 VIRTIO_BLK_F_WCE, VIRTIO_BLK_F_TOPOLOGY, VIRTIO_BLK_F_CONFIG_WCE, 837 VIRTIO_BLK_F_MQ, 838} 839; 840static unsigned int features[] = { 841 VIRTIO_BLK_F_SEG_MAX, VIRTIO_BLK_F_SIZE_MAX, VIRTIO_BLK_F_GEOMETRY, 842 VIRTIO_BLK_F_RO, VIRTIO_BLK_F_BLK_SIZE, 843 VIRTIO_BLK_F_WCE, VIRTIO_BLK_F_TOPOLOGY, VIRTIO_BLK_F_CONFIG_WCE, 844 VIRTIO_BLK_F_MQ, 845}; 846 847static struct virtio_driver virtio_blk = { 848 .feature_table = features, 849 .feature_table_size = ARRAY_SIZE(features), 850 .feature_table_legacy = features_legacy, 851 .feature_table_size_legacy = ARRAY_SIZE(features_legacy), 852 .driver.name = KBUILD_MODNAME, 853 .driver.owner = THIS_MODULE, 854 .id_table = id_table, 855 .probe = virtblk_probe, 856 .remove = virtblk_remove, 857 .config_changed = virtblk_config_changed, 858#ifdef CONFIG_PM_SLEEP 859 .freeze = virtblk_freeze, 860 .restore = virtblk_restore, 861#endif 862}; 863 864static int __init init(void) 865{ 866 int error; 867 868 virtblk_wq = alloc_workqueue("virtio-blk", 0, 0); 869 if (!virtblk_wq) 870 return -ENOMEM; 871 872 major = register_blkdev(0, "virtblk"); 873 if (major < 0) { 874 error = major; 875 goto out_destroy_workqueue; 876 } 877 878 error = register_virtio_driver(&virtio_blk); 879 if (error) 880 goto out_unregister_blkdev; 881 return 0; 882 883out_unregister_blkdev: 884 unregister_blkdev(major, "virtblk"); 885out_destroy_workqueue: 886 destroy_workqueue(virtblk_wq); 887 return error; 888} 889 890static void __exit fini(void) 891{ 892 unregister_virtio_driver(&virtio_blk); 893 unregister_blkdev(major, "virtblk"); 894 destroy_workqueue(virtblk_wq); 895} 896module_init(init); 897module_exit(fini); 898 899MODULE_DEVICE_TABLE(virtio, id_table); 900MODULE_DESCRIPTION("Virtio block driver"); 901MODULE_LICENSE("GPL"); 902