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 15 #define PART_BITS 4 16 17 static bool use_bio; 18 module_param(use_bio, bool, S_IRUGO); 19 20 static int major; 21 static DEFINE_IDA(vd_index_ida); 22 23 struct workqueue_struct *virtblk_wq; 24 25 struct virtio_blk 26 { 27 struct virtio_device *vdev; 28 struct virtqueue *vq; 29 wait_queue_head_t queue_wait; 30 31 /* The disk structure for the kernel. */ 32 struct gendisk *disk; 33 34 mempool_t *pool; 35 36 /* Process context for config space updates */ 37 struct work_struct config_work; 38 39 /* Lock for config space updates */ 40 struct mutex config_lock; 41 42 /* enable config space updates */ 43 bool config_enable; 44 45 /* What host tells us, plus 2 for header & tailer. */ 46 unsigned int sg_elems; 47 48 /* Ida index - used to track minor number allocations. */ 49 int index; 50 51 /* Scatterlist: can be too big for stack. */ 52 struct scatterlist sg[/*sg_elems*/]; 53 }; 54 55 struct virtblk_req 56 { 57 struct request *req; 58 struct bio *bio; 59 struct virtio_blk_outhdr out_hdr; 60 struct virtio_scsi_inhdr in_hdr; 61 struct work_struct work; 62 struct virtio_blk *vblk; 63 int flags; 64 u8 status; 65 struct scatterlist sg[]; 66 }; 67 68 enum { 69 VBLK_IS_FLUSH = 1, 70 VBLK_REQ_FLUSH = 2, 71 VBLK_REQ_DATA = 4, 72 VBLK_REQ_FUA = 8, 73 }; 74 75 static inline int virtblk_result(struct virtblk_req *vbr) 76 { 77 switch (vbr->status) { 78 case VIRTIO_BLK_S_OK: 79 return 0; 80 case VIRTIO_BLK_S_UNSUPP: 81 return -ENOTTY; 82 default: 83 return -EIO; 84 } 85 } 86 87 static inline struct virtblk_req *virtblk_alloc_req(struct virtio_blk *vblk, 88 gfp_t gfp_mask) 89 { 90 struct virtblk_req *vbr; 91 92 vbr = mempool_alloc(vblk->pool, gfp_mask); 93 if (!vbr) 94 return NULL; 95 96 vbr->vblk = vblk; 97 if (use_bio) 98 sg_init_table(vbr->sg, vblk->sg_elems); 99 100 return vbr; 101 } 102 103 static void virtblk_add_buf_wait(struct virtio_blk *vblk, 104 struct virtblk_req *vbr, 105 unsigned long out, 106 unsigned long in) 107 { 108 DEFINE_WAIT(wait); 109 110 for (;;) { 111 prepare_to_wait_exclusive(&vblk->queue_wait, &wait, 112 TASK_UNINTERRUPTIBLE); 113 114 spin_lock_irq(vblk->disk->queue->queue_lock); 115 if (virtqueue_add_buf(vblk->vq, vbr->sg, out, in, vbr, 116 GFP_ATOMIC) < 0) { 117 spin_unlock_irq(vblk->disk->queue->queue_lock); 118 io_schedule(); 119 } else { 120 virtqueue_kick(vblk->vq); 121 spin_unlock_irq(vblk->disk->queue->queue_lock); 122 break; 123 } 124 125 } 126 127 finish_wait(&vblk->queue_wait, &wait); 128 } 129 130 static inline void virtblk_add_req(struct virtblk_req *vbr, 131 unsigned int out, unsigned int in) 132 { 133 struct virtio_blk *vblk = vbr->vblk; 134 135 spin_lock_irq(vblk->disk->queue->queue_lock); 136 if (unlikely(virtqueue_add_buf(vblk->vq, vbr->sg, out, in, vbr, 137 GFP_ATOMIC) < 0)) { 138 spin_unlock_irq(vblk->disk->queue->queue_lock); 139 virtblk_add_buf_wait(vblk, vbr, out, in); 140 return; 141 } 142 virtqueue_kick(vblk->vq); 143 spin_unlock_irq(vblk->disk->queue->queue_lock); 144 } 145 146 static int virtblk_bio_send_flush(struct virtblk_req *vbr) 147 { 148 unsigned int out = 0, in = 0; 149 150 vbr->flags |= VBLK_IS_FLUSH; 151 vbr->out_hdr.type = VIRTIO_BLK_T_FLUSH; 152 vbr->out_hdr.sector = 0; 153 vbr->out_hdr.ioprio = 0; 154 sg_set_buf(&vbr->sg[out++], &vbr->out_hdr, sizeof(vbr->out_hdr)); 155 sg_set_buf(&vbr->sg[out + in++], &vbr->status, sizeof(vbr->status)); 156 157 virtblk_add_req(vbr, out, in); 158 159 return 0; 160 } 161 162 static int virtblk_bio_send_data(struct virtblk_req *vbr) 163 { 164 struct virtio_blk *vblk = vbr->vblk; 165 unsigned int num, out = 0, in = 0; 166 struct bio *bio = vbr->bio; 167 168 vbr->flags &= ~VBLK_IS_FLUSH; 169 vbr->out_hdr.type = 0; 170 vbr->out_hdr.sector = bio->bi_sector; 171 vbr->out_hdr.ioprio = bio_prio(bio); 172 173 sg_set_buf(&vbr->sg[out++], &vbr->out_hdr, sizeof(vbr->out_hdr)); 174 175 num = blk_bio_map_sg(vblk->disk->queue, bio, vbr->sg + out); 176 177 sg_set_buf(&vbr->sg[num + out + in++], &vbr->status, 178 sizeof(vbr->status)); 179 180 if (num) { 181 if (bio->bi_rw & REQ_WRITE) { 182 vbr->out_hdr.type |= VIRTIO_BLK_T_OUT; 183 out += num; 184 } else { 185 vbr->out_hdr.type |= VIRTIO_BLK_T_IN; 186 in += num; 187 } 188 } 189 190 virtblk_add_req(vbr, out, in); 191 192 return 0; 193 } 194 195 static void virtblk_bio_send_data_work(struct work_struct *work) 196 { 197 struct virtblk_req *vbr; 198 199 vbr = container_of(work, struct virtblk_req, work); 200 201 virtblk_bio_send_data(vbr); 202 } 203 204 static void virtblk_bio_send_flush_work(struct work_struct *work) 205 { 206 struct virtblk_req *vbr; 207 208 vbr = container_of(work, struct virtblk_req, work); 209 210 virtblk_bio_send_flush(vbr); 211 } 212 213 static inline void virtblk_request_done(struct virtblk_req *vbr) 214 { 215 struct virtio_blk *vblk = vbr->vblk; 216 struct request *req = vbr->req; 217 int error = virtblk_result(vbr); 218 219 if (req->cmd_type == REQ_TYPE_BLOCK_PC) { 220 req->resid_len = vbr->in_hdr.residual; 221 req->sense_len = vbr->in_hdr.sense_len; 222 req->errors = vbr->in_hdr.errors; 223 } else if (req->cmd_type == REQ_TYPE_SPECIAL) { 224 req->errors = (error != 0); 225 } 226 227 __blk_end_request_all(req, error); 228 mempool_free(vbr, vblk->pool); 229 } 230 231 static inline void virtblk_bio_flush_done(struct virtblk_req *vbr) 232 { 233 struct virtio_blk *vblk = vbr->vblk; 234 235 if (vbr->flags & VBLK_REQ_DATA) { 236 /* Send out the actual write data */ 237 INIT_WORK(&vbr->work, virtblk_bio_send_data_work); 238 queue_work(virtblk_wq, &vbr->work); 239 } else { 240 bio_endio(vbr->bio, virtblk_result(vbr)); 241 mempool_free(vbr, vblk->pool); 242 } 243 } 244 245 static inline void virtblk_bio_data_done(struct virtblk_req *vbr) 246 { 247 struct virtio_blk *vblk = vbr->vblk; 248 249 if (unlikely(vbr->flags & VBLK_REQ_FUA)) { 250 /* Send out a flush before end the bio */ 251 vbr->flags &= ~VBLK_REQ_DATA; 252 INIT_WORK(&vbr->work, virtblk_bio_send_flush_work); 253 queue_work(virtblk_wq, &vbr->work); 254 } else { 255 bio_endio(vbr->bio, virtblk_result(vbr)); 256 mempool_free(vbr, vblk->pool); 257 } 258 } 259 260 static inline void virtblk_bio_done(struct virtblk_req *vbr) 261 { 262 if (unlikely(vbr->flags & VBLK_IS_FLUSH)) 263 virtblk_bio_flush_done(vbr); 264 else 265 virtblk_bio_data_done(vbr); 266 } 267 268 static void virtblk_done(struct virtqueue *vq) 269 { 270 struct virtio_blk *vblk = vq->vdev->priv; 271 bool bio_done = false, req_done = false; 272 struct virtblk_req *vbr; 273 unsigned long flags; 274 unsigned int len; 275 276 spin_lock_irqsave(vblk->disk->queue->queue_lock, flags); 277 do { 278 virtqueue_disable_cb(vq); 279 while ((vbr = virtqueue_get_buf(vblk->vq, &len)) != NULL) { 280 if (vbr->bio) { 281 virtblk_bio_done(vbr); 282 bio_done = true; 283 } else { 284 virtblk_request_done(vbr); 285 req_done = true; 286 } 287 } 288 } while (!virtqueue_enable_cb(vq)); 289 /* In case queue is stopped waiting for more buffers. */ 290 if (req_done) 291 blk_start_queue(vblk->disk->queue); 292 spin_unlock_irqrestore(vblk->disk->queue->queue_lock, flags); 293 294 if (bio_done) 295 wake_up(&vblk->queue_wait); 296 } 297 298 static bool do_req(struct request_queue *q, struct virtio_blk *vblk, 299 struct request *req) 300 { 301 unsigned long num, out = 0, in = 0; 302 struct virtblk_req *vbr; 303 304 vbr = virtblk_alloc_req(vblk, GFP_ATOMIC); 305 if (!vbr) 306 /* When another request finishes we'll try again. */ 307 return false; 308 309 vbr->req = req; 310 vbr->bio = NULL; 311 if (req->cmd_flags & REQ_FLUSH) { 312 vbr->out_hdr.type = VIRTIO_BLK_T_FLUSH; 313 vbr->out_hdr.sector = 0; 314 vbr->out_hdr.ioprio = req_get_ioprio(vbr->req); 315 } else { 316 switch (req->cmd_type) { 317 case REQ_TYPE_FS: 318 vbr->out_hdr.type = 0; 319 vbr->out_hdr.sector = blk_rq_pos(vbr->req); 320 vbr->out_hdr.ioprio = req_get_ioprio(vbr->req); 321 break; 322 case REQ_TYPE_BLOCK_PC: 323 vbr->out_hdr.type = VIRTIO_BLK_T_SCSI_CMD; 324 vbr->out_hdr.sector = 0; 325 vbr->out_hdr.ioprio = req_get_ioprio(vbr->req); 326 break; 327 case REQ_TYPE_SPECIAL: 328 vbr->out_hdr.type = VIRTIO_BLK_T_GET_ID; 329 vbr->out_hdr.sector = 0; 330 vbr->out_hdr.ioprio = req_get_ioprio(vbr->req); 331 break; 332 default: 333 /* We don't put anything else in the queue. */ 334 BUG(); 335 } 336 } 337 338 sg_set_buf(&vblk->sg[out++], &vbr->out_hdr, sizeof(vbr->out_hdr)); 339 340 /* 341 * If this is a packet command we need a couple of additional headers. 342 * Behind the normal outhdr we put a segment with the scsi command 343 * block, and before the normal inhdr we put the sense data and the 344 * inhdr with additional status information before the normal inhdr. 345 */ 346 if (vbr->req->cmd_type == REQ_TYPE_BLOCK_PC) 347 sg_set_buf(&vblk->sg[out++], vbr->req->cmd, vbr->req->cmd_len); 348 349 num = blk_rq_map_sg(q, vbr->req, vblk->sg + out); 350 351 if (vbr->req->cmd_type == REQ_TYPE_BLOCK_PC) { 352 sg_set_buf(&vblk->sg[num + out + in++], vbr->req->sense, SCSI_SENSE_BUFFERSIZE); 353 sg_set_buf(&vblk->sg[num + out + in++], &vbr->in_hdr, 354 sizeof(vbr->in_hdr)); 355 } 356 357 sg_set_buf(&vblk->sg[num + out + in++], &vbr->status, 358 sizeof(vbr->status)); 359 360 if (num) { 361 if (rq_data_dir(vbr->req) == WRITE) { 362 vbr->out_hdr.type |= VIRTIO_BLK_T_OUT; 363 out += num; 364 } else { 365 vbr->out_hdr.type |= VIRTIO_BLK_T_IN; 366 in += num; 367 } 368 } 369 370 if (virtqueue_add_buf(vblk->vq, vblk->sg, out, in, vbr, 371 GFP_ATOMIC) < 0) { 372 mempool_free(vbr, vblk->pool); 373 return false; 374 } 375 376 return true; 377 } 378 379 static void virtblk_request(struct request_queue *q) 380 { 381 struct virtio_blk *vblk = q->queuedata; 382 struct request *req; 383 unsigned int issued = 0; 384 385 while ((req = blk_peek_request(q)) != NULL) { 386 BUG_ON(req->nr_phys_segments + 2 > vblk->sg_elems); 387 388 /* If this request fails, stop queue and wait for something to 389 finish to restart it. */ 390 if (!do_req(q, vblk, req)) { 391 blk_stop_queue(q); 392 break; 393 } 394 blk_start_request(req); 395 issued++; 396 } 397 398 if (issued) 399 virtqueue_kick(vblk->vq); 400 } 401 402 static void virtblk_make_request(struct request_queue *q, struct bio *bio) 403 { 404 struct virtio_blk *vblk = q->queuedata; 405 struct virtblk_req *vbr; 406 407 BUG_ON(bio->bi_phys_segments + 2 > vblk->sg_elems); 408 409 vbr = virtblk_alloc_req(vblk, GFP_NOIO); 410 if (!vbr) { 411 bio_endio(bio, -ENOMEM); 412 return; 413 } 414 415 vbr->bio = bio; 416 vbr->flags = 0; 417 if (bio->bi_rw & REQ_FLUSH) 418 vbr->flags |= VBLK_REQ_FLUSH; 419 if (bio->bi_rw & REQ_FUA) 420 vbr->flags |= VBLK_REQ_FUA; 421 if (bio->bi_size) 422 vbr->flags |= VBLK_REQ_DATA; 423 424 if (unlikely(vbr->flags & VBLK_REQ_FLUSH)) 425 virtblk_bio_send_flush(vbr); 426 else 427 virtblk_bio_send_data(vbr); 428 } 429 430 /* return id (s/n) string for *disk to *id_str 431 */ 432 static int virtblk_get_id(struct gendisk *disk, char *id_str) 433 { 434 struct virtio_blk *vblk = disk->private_data; 435 struct request *req; 436 struct bio *bio; 437 int err; 438 439 bio = bio_map_kern(vblk->disk->queue, id_str, VIRTIO_BLK_ID_BYTES, 440 GFP_KERNEL); 441 if (IS_ERR(bio)) 442 return PTR_ERR(bio); 443 444 req = blk_make_request(vblk->disk->queue, bio, GFP_KERNEL); 445 if (IS_ERR(req)) { 446 bio_put(bio); 447 return PTR_ERR(req); 448 } 449 450 req->cmd_type = REQ_TYPE_SPECIAL; 451 err = blk_execute_rq(vblk->disk->queue, vblk->disk, req, false); 452 blk_put_request(req); 453 454 return err; 455 } 456 457 static int virtblk_ioctl(struct block_device *bdev, fmode_t mode, 458 unsigned int cmd, unsigned long data) 459 { 460 struct gendisk *disk = bdev->bd_disk; 461 struct virtio_blk *vblk = disk->private_data; 462 463 /* 464 * Only allow the generic SCSI ioctls if the host can support it. 465 */ 466 if (!virtio_has_feature(vblk->vdev, VIRTIO_BLK_F_SCSI)) 467 return -ENOTTY; 468 469 return scsi_cmd_blk_ioctl(bdev, mode, cmd, 470 (void __user *)data); 471 } 472 473 /* We provide getgeo only to please some old bootloader/partitioning tools */ 474 static int virtblk_getgeo(struct block_device *bd, struct hd_geometry *geo) 475 { 476 struct virtio_blk *vblk = bd->bd_disk->private_data; 477 struct virtio_blk_geometry vgeo; 478 int err; 479 480 /* see if the host passed in geometry config */ 481 err = virtio_config_val(vblk->vdev, VIRTIO_BLK_F_GEOMETRY, 482 offsetof(struct virtio_blk_config, geometry), 483 &vgeo); 484 485 if (!err) { 486 geo->heads = vgeo.heads; 487 geo->sectors = vgeo.sectors; 488 geo->cylinders = vgeo.cylinders; 489 } else { 490 /* some standard values, similar to sd */ 491 geo->heads = 1 << 6; 492 geo->sectors = 1 << 5; 493 geo->cylinders = get_capacity(bd->bd_disk) >> 11; 494 } 495 return 0; 496 } 497 498 static const struct block_device_operations virtblk_fops = { 499 .ioctl = virtblk_ioctl, 500 .owner = THIS_MODULE, 501 .getgeo = virtblk_getgeo, 502 }; 503 504 static int index_to_minor(int index) 505 { 506 return index << PART_BITS; 507 } 508 509 static int minor_to_index(int minor) 510 { 511 return minor >> PART_BITS; 512 } 513 514 static ssize_t virtblk_serial_show(struct device *dev, 515 struct device_attribute *attr, char *buf) 516 { 517 struct gendisk *disk = dev_to_disk(dev); 518 int err; 519 520 /* sysfs gives us a PAGE_SIZE buffer */ 521 BUILD_BUG_ON(PAGE_SIZE < VIRTIO_BLK_ID_BYTES); 522 523 buf[VIRTIO_BLK_ID_BYTES] = '\0'; 524 err = virtblk_get_id(disk, buf); 525 if (!err) 526 return strlen(buf); 527 528 if (err == -EIO) /* Unsupported? Make it empty. */ 529 return 0; 530 531 return err; 532 } 533 DEVICE_ATTR(serial, S_IRUGO, virtblk_serial_show, NULL); 534 535 static void virtblk_config_changed_work(struct work_struct *work) 536 { 537 struct virtio_blk *vblk = 538 container_of(work, struct virtio_blk, config_work); 539 struct virtio_device *vdev = vblk->vdev; 540 struct request_queue *q = vblk->disk->queue; 541 char cap_str_2[10], cap_str_10[10]; 542 char *envp[] = { "RESIZE=1", NULL }; 543 u64 capacity, size; 544 545 mutex_lock(&vblk->config_lock); 546 if (!vblk->config_enable) 547 goto done; 548 549 /* Host must always specify the capacity. */ 550 vdev->config->get(vdev, offsetof(struct virtio_blk_config, capacity), 551 &capacity, sizeof(capacity)); 552 553 /* If capacity is too big, truncate with warning. */ 554 if ((sector_t)capacity != capacity) { 555 dev_warn(&vdev->dev, "Capacity %llu too large: truncating\n", 556 (unsigned long long)capacity); 557 capacity = (sector_t)-1; 558 } 559 560 size = capacity * queue_logical_block_size(q); 561 string_get_size(size, STRING_UNITS_2, cap_str_2, sizeof(cap_str_2)); 562 string_get_size(size, STRING_UNITS_10, cap_str_10, sizeof(cap_str_10)); 563 564 dev_notice(&vdev->dev, 565 "new size: %llu %d-byte logical blocks (%s/%s)\n", 566 (unsigned long long)capacity, 567 queue_logical_block_size(q), 568 cap_str_10, cap_str_2); 569 570 set_capacity(vblk->disk, capacity); 571 revalidate_disk(vblk->disk); 572 kobject_uevent_env(&disk_to_dev(vblk->disk)->kobj, KOBJ_CHANGE, envp); 573 done: 574 mutex_unlock(&vblk->config_lock); 575 } 576 577 static void virtblk_config_changed(struct virtio_device *vdev) 578 { 579 struct virtio_blk *vblk = vdev->priv; 580 581 queue_work(virtblk_wq, &vblk->config_work); 582 } 583 584 static int init_vq(struct virtio_blk *vblk) 585 { 586 int err = 0; 587 588 /* We expect one virtqueue, for output. */ 589 vblk->vq = virtio_find_single_vq(vblk->vdev, virtblk_done, "requests"); 590 if (IS_ERR(vblk->vq)) 591 err = PTR_ERR(vblk->vq); 592 593 return err; 594 } 595 596 /* 597 * Legacy naming scheme used for virtio devices. We are stuck with it for 598 * virtio blk but don't ever use it for any new driver. 599 */ 600 static int virtblk_name_format(char *prefix, int index, char *buf, int buflen) 601 { 602 const int base = 'z' - 'a' + 1; 603 char *begin = buf + strlen(prefix); 604 char *end = buf + buflen; 605 char *p; 606 int unit; 607 608 p = end - 1; 609 *p = '\0'; 610 unit = base; 611 do { 612 if (p == begin) 613 return -EINVAL; 614 *--p = 'a' + (index % unit); 615 index = (index / unit) - 1; 616 } while (index >= 0); 617 618 memmove(begin, p, end - p); 619 memcpy(buf, prefix, strlen(prefix)); 620 621 return 0; 622 } 623 624 static int virtblk_get_cache_mode(struct virtio_device *vdev) 625 { 626 u8 writeback; 627 int err; 628 629 err = virtio_config_val(vdev, VIRTIO_BLK_F_CONFIG_WCE, 630 offsetof(struct virtio_blk_config, wce), 631 &writeback); 632 if (err) 633 writeback = virtio_has_feature(vdev, VIRTIO_BLK_F_WCE); 634 635 return writeback; 636 } 637 638 static void virtblk_update_cache_mode(struct virtio_device *vdev) 639 { 640 u8 writeback = virtblk_get_cache_mode(vdev); 641 struct virtio_blk *vblk = vdev->priv; 642 643 if (writeback) 644 blk_queue_flush(vblk->disk->queue, REQ_FLUSH); 645 else 646 blk_queue_flush(vblk->disk->queue, 0); 647 648 revalidate_disk(vblk->disk); 649 } 650 651 static const char *const virtblk_cache_types[] = { 652 "write through", "write back" 653 }; 654 655 static ssize_t 656 virtblk_cache_type_store(struct device *dev, struct device_attribute *attr, 657 const char *buf, size_t count) 658 { 659 struct gendisk *disk = dev_to_disk(dev); 660 struct virtio_blk *vblk = disk->private_data; 661 struct virtio_device *vdev = vblk->vdev; 662 int i; 663 u8 writeback; 664 665 BUG_ON(!virtio_has_feature(vblk->vdev, VIRTIO_BLK_F_CONFIG_WCE)); 666 for (i = ARRAY_SIZE(virtblk_cache_types); --i >= 0; ) 667 if (sysfs_streq(buf, virtblk_cache_types[i])) 668 break; 669 670 if (i < 0) 671 return -EINVAL; 672 673 writeback = i; 674 vdev->config->set(vdev, 675 offsetof(struct virtio_blk_config, wce), 676 &writeback, sizeof(writeback)); 677 678 virtblk_update_cache_mode(vdev); 679 return count; 680 } 681 682 static ssize_t 683 virtblk_cache_type_show(struct device *dev, struct device_attribute *attr, 684 char *buf) 685 { 686 struct gendisk *disk = dev_to_disk(dev); 687 struct virtio_blk *vblk = disk->private_data; 688 u8 writeback = virtblk_get_cache_mode(vblk->vdev); 689 690 BUG_ON(writeback >= ARRAY_SIZE(virtblk_cache_types)); 691 return snprintf(buf, 40, "%s\n", virtblk_cache_types[writeback]); 692 } 693 694 static const struct device_attribute dev_attr_cache_type_ro = 695 __ATTR(cache_type, S_IRUGO, 696 virtblk_cache_type_show, NULL); 697 static const struct device_attribute dev_attr_cache_type_rw = 698 __ATTR(cache_type, S_IRUGO|S_IWUSR, 699 virtblk_cache_type_show, virtblk_cache_type_store); 700 701 static int virtblk_probe(struct virtio_device *vdev) 702 { 703 struct virtio_blk *vblk; 704 struct request_queue *q; 705 int err, index; 706 int pool_size; 707 708 u64 cap; 709 u32 v, blk_size, sg_elems, opt_io_size; 710 u16 min_io_size; 711 u8 physical_block_exp, alignment_offset; 712 713 err = ida_simple_get(&vd_index_ida, 0, minor_to_index(1 << MINORBITS), 714 GFP_KERNEL); 715 if (err < 0) 716 goto out; 717 index = err; 718 719 /* We need to know how many segments before we allocate. */ 720 err = virtio_config_val(vdev, VIRTIO_BLK_F_SEG_MAX, 721 offsetof(struct virtio_blk_config, seg_max), 722 &sg_elems); 723 724 /* We need at least one SG element, whatever they say. */ 725 if (err || !sg_elems) 726 sg_elems = 1; 727 728 /* We need an extra sg elements at head and tail. */ 729 sg_elems += 2; 730 vdev->priv = vblk = kmalloc(sizeof(*vblk) + 731 sizeof(vblk->sg[0]) * sg_elems, GFP_KERNEL); 732 if (!vblk) { 733 err = -ENOMEM; 734 goto out_free_index; 735 } 736 737 init_waitqueue_head(&vblk->queue_wait); 738 vblk->vdev = vdev; 739 vblk->sg_elems = sg_elems; 740 sg_init_table(vblk->sg, vblk->sg_elems); 741 mutex_init(&vblk->config_lock); 742 743 INIT_WORK(&vblk->config_work, virtblk_config_changed_work); 744 vblk->config_enable = true; 745 746 err = init_vq(vblk); 747 if (err) 748 goto out_free_vblk; 749 750 pool_size = sizeof(struct virtblk_req); 751 if (use_bio) 752 pool_size += sizeof(struct scatterlist) * sg_elems; 753 vblk->pool = mempool_create_kmalloc_pool(1, pool_size); 754 if (!vblk->pool) { 755 err = -ENOMEM; 756 goto out_free_vq; 757 } 758 759 /* FIXME: How many partitions? How long is a piece of string? */ 760 vblk->disk = alloc_disk(1 << PART_BITS); 761 if (!vblk->disk) { 762 err = -ENOMEM; 763 goto out_mempool; 764 } 765 766 q = vblk->disk->queue = blk_init_queue(virtblk_request, NULL); 767 if (!q) { 768 err = -ENOMEM; 769 goto out_put_disk; 770 } 771 772 if (use_bio) 773 blk_queue_make_request(q, virtblk_make_request); 774 q->queuedata = vblk; 775 776 virtblk_name_format("vd", index, vblk->disk->disk_name, DISK_NAME_LEN); 777 778 vblk->disk->major = major; 779 vblk->disk->first_minor = index_to_minor(index); 780 vblk->disk->private_data = vblk; 781 vblk->disk->fops = &virtblk_fops; 782 vblk->disk->driverfs_dev = &vdev->dev; 783 vblk->index = index; 784 785 /* configure queue flush support */ 786 virtblk_update_cache_mode(vdev); 787 788 /* If disk is read-only in the host, the guest should obey */ 789 if (virtio_has_feature(vdev, VIRTIO_BLK_F_RO)) 790 set_disk_ro(vblk->disk, 1); 791 792 /* Host must always specify the capacity. */ 793 vdev->config->get(vdev, offsetof(struct virtio_blk_config, capacity), 794 &cap, sizeof(cap)); 795 796 /* If capacity is too big, truncate with warning. */ 797 if ((sector_t)cap != cap) { 798 dev_warn(&vdev->dev, "Capacity %llu too large: truncating\n", 799 (unsigned long long)cap); 800 cap = (sector_t)-1; 801 } 802 set_capacity(vblk->disk, cap); 803 804 /* We can handle whatever the host told us to handle. */ 805 blk_queue_max_segments(q, vblk->sg_elems-2); 806 807 /* No need to bounce any requests */ 808 blk_queue_bounce_limit(q, BLK_BOUNCE_ANY); 809 810 /* No real sector limit. */ 811 blk_queue_max_hw_sectors(q, -1U); 812 813 /* Host can optionally specify maximum segment size and number of 814 * segments. */ 815 err = virtio_config_val(vdev, VIRTIO_BLK_F_SIZE_MAX, 816 offsetof(struct virtio_blk_config, size_max), 817 &v); 818 if (!err) 819 blk_queue_max_segment_size(q, v); 820 else 821 blk_queue_max_segment_size(q, -1U); 822 823 /* Host can optionally specify the block size of the device */ 824 err = virtio_config_val(vdev, VIRTIO_BLK_F_BLK_SIZE, 825 offsetof(struct virtio_blk_config, blk_size), 826 &blk_size); 827 if (!err) 828 blk_queue_logical_block_size(q, blk_size); 829 else 830 blk_size = queue_logical_block_size(q); 831 832 /* Use topology information if available */ 833 err = virtio_config_val(vdev, VIRTIO_BLK_F_TOPOLOGY, 834 offsetof(struct virtio_blk_config, physical_block_exp), 835 &physical_block_exp); 836 if (!err && physical_block_exp) 837 blk_queue_physical_block_size(q, 838 blk_size * (1 << physical_block_exp)); 839 840 err = virtio_config_val(vdev, VIRTIO_BLK_F_TOPOLOGY, 841 offsetof(struct virtio_blk_config, alignment_offset), 842 &alignment_offset); 843 if (!err && alignment_offset) 844 blk_queue_alignment_offset(q, blk_size * alignment_offset); 845 846 err = virtio_config_val(vdev, VIRTIO_BLK_F_TOPOLOGY, 847 offsetof(struct virtio_blk_config, min_io_size), 848 &min_io_size); 849 if (!err && min_io_size) 850 blk_queue_io_min(q, blk_size * min_io_size); 851 852 err = virtio_config_val(vdev, VIRTIO_BLK_F_TOPOLOGY, 853 offsetof(struct virtio_blk_config, opt_io_size), 854 &opt_io_size); 855 if (!err && opt_io_size) 856 blk_queue_io_opt(q, blk_size * opt_io_size); 857 858 add_disk(vblk->disk); 859 err = device_create_file(disk_to_dev(vblk->disk), &dev_attr_serial); 860 if (err) 861 goto out_del_disk; 862 863 if (virtio_has_feature(vdev, VIRTIO_BLK_F_CONFIG_WCE)) 864 err = device_create_file(disk_to_dev(vblk->disk), 865 &dev_attr_cache_type_rw); 866 else 867 err = device_create_file(disk_to_dev(vblk->disk), 868 &dev_attr_cache_type_ro); 869 if (err) 870 goto out_del_disk; 871 return 0; 872 873 out_del_disk: 874 del_gendisk(vblk->disk); 875 blk_cleanup_queue(vblk->disk->queue); 876 out_put_disk: 877 put_disk(vblk->disk); 878 out_mempool: 879 mempool_destroy(vblk->pool); 880 out_free_vq: 881 vdev->config->del_vqs(vdev); 882 out_free_vblk: 883 kfree(vblk); 884 out_free_index: 885 ida_simple_remove(&vd_index_ida, index); 886 out: 887 return err; 888 } 889 890 static void virtblk_remove(struct virtio_device *vdev) 891 { 892 struct virtio_blk *vblk = vdev->priv; 893 int index = vblk->index; 894 int refc; 895 896 /* Prevent config work handler from accessing the device. */ 897 mutex_lock(&vblk->config_lock); 898 vblk->config_enable = false; 899 mutex_unlock(&vblk->config_lock); 900 901 del_gendisk(vblk->disk); 902 blk_cleanup_queue(vblk->disk->queue); 903 904 /* Stop all the virtqueues. */ 905 vdev->config->reset(vdev); 906 907 flush_work(&vblk->config_work); 908 909 refc = atomic_read(&disk_to_dev(vblk->disk)->kobj.kref.refcount); 910 put_disk(vblk->disk); 911 mempool_destroy(vblk->pool); 912 vdev->config->del_vqs(vdev); 913 kfree(vblk); 914 915 /* Only free device id if we don't have any users */ 916 if (refc == 1) 917 ida_simple_remove(&vd_index_ida, index); 918 } 919 920 #ifdef CONFIG_PM 921 static int virtblk_freeze(struct virtio_device *vdev) 922 { 923 struct virtio_blk *vblk = vdev->priv; 924 925 /* Ensure we don't receive any more interrupts */ 926 vdev->config->reset(vdev); 927 928 /* Prevent config work handler from accessing the device. */ 929 mutex_lock(&vblk->config_lock); 930 vblk->config_enable = false; 931 mutex_unlock(&vblk->config_lock); 932 933 flush_work(&vblk->config_work); 934 935 spin_lock_irq(vblk->disk->queue->queue_lock); 936 blk_stop_queue(vblk->disk->queue); 937 spin_unlock_irq(vblk->disk->queue->queue_lock); 938 blk_sync_queue(vblk->disk->queue); 939 940 vdev->config->del_vqs(vdev); 941 return 0; 942 } 943 944 static int virtblk_restore(struct virtio_device *vdev) 945 { 946 struct virtio_blk *vblk = vdev->priv; 947 int ret; 948 949 vblk->config_enable = true; 950 ret = init_vq(vdev->priv); 951 if (!ret) { 952 spin_lock_irq(vblk->disk->queue->queue_lock); 953 blk_start_queue(vblk->disk->queue); 954 spin_unlock_irq(vblk->disk->queue->queue_lock); 955 } 956 return ret; 957 } 958 #endif 959 960 static const struct virtio_device_id id_table[] = { 961 { VIRTIO_ID_BLOCK, VIRTIO_DEV_ANY_ID }, 962 { 0 }, 963 }; 964 965 static unsigned int features[] = { 966 VIRTIO_BLK_F_SEG_MAX, VIRTIO_BLK_F_SIZE_MAX, VIRTIO_BLK_F_GEOMETRY, 967 VIRTIO_BLK_F_RO, VIRTIO_BLK_F_BLK_SIZE, VIRTIO_BLK_F_SCSI, 968 VIRTIO_BLK_F_WCE, VIRTIO_BLK_F_TOPOLOGY, VIRTIO_BLK_F_CONFIG_WCE 969 }; 970 971 static struct virtio_driver virtio_blk = { 972 .feature_table = features, 973 .feature_table_size = ARRAY_SIZE(features), 974 .driver.name = KBUILD_MODNAME, 975 .driver.owner = THIS_MODULE, 976 .id_table = id_table, 977 .probe = virtblk_probe, 978 .remove = virtblk_remove, 979 .config_changed = virtblk_config_changed, 980 #ifdef CONFIG_PM 981 .freeze = virtblk_freeze, 982 .restore = virtblk_restore, 983 #endif 984 }; 985 986 static int __init init(void) 987 { 988 int error; 989 990 virtblk_wq = alloc_workqueue("virtio-blk", 0, 0); 991 if (!virtblk_wq) 992 return -ENOMEM; 993 994 major = register_blkdev(0, "virtblk"); 995 if (major < 0) { 996 error = major; 997 goto out_destroy_workqueue; 998 } 999 1000 error = register_virtio_driver(&virtio_blk); 1001 if (error) 1002 goto out_unregister_blkdev; 1003 return 0; 1004 1005 out_unregister_blkdev: 1006 unregister_blkdev(major, "virtblk"); 1007 out_destroy_workqueue: 1008 destroy_workqueue(virtblk_wq); 1009 return error; 1010 } 1011 1012 static void __exit fini(void) 1013 { 1014 unregister_blkdev(major, "virtblk"); 1015 unregister_virtio_driver(&virtio_blk); 1016 destroy_workqueue(virtblk_wq); 1017 } 1018 module_init(init); 1019 module_exit(fini); 1020 1021 MODULE_DEVICE_TABLE(virtio, id_table); 1022 MODULE_DESCRIPTION("Virtio block driver"); 1023 MODULE_LICENSE("GPL"); 1024