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 u64 capacity, size; 543 544 mutex_lock(&vblk->config_lock); 545 if (!vblk->config_enable) 546 goto done; 547 548 /* Host must always specify the capacity. */ 549 vdev->config->get(vdev, offsetof(struct virtio_blk_config, capacity), 550 &capacity, sizeof(capacity)); 551 552 /* If capacity is too big, truncate with warning. */ 553 if ((sector_t)capacity != capacity) { 554 dev_warn(&vdev->dev, "Capacity %llu too large: truncating\n", 555 (unsigned long long)capacity); 556 capacity = (sector_t)-1; 557 } 558 559 size = capacity * queue_logical_block_size(q); 560 string_get_size(size, STRING_UNITS_2, cap_str_2, sizeof(cap_str_2)); 561 string_get_size(size, STRING_UNITS_10, cap_str_10, sizeof(cap_str_10)); 562 563 dev_notice(&vdev->dev, 564 "new size: %llu %d-byte logical blocks (%s/%s)\n", 565 (unsigned long long)capacity, 566 queue_logical_block_size(q), 567 cap_str_10, cap_str_2); 568 569 set_capacity(vblk->disk, capacity); 570 revalidate_disk(vblk->disk); 571 done: 572 mutex_unlock(&vblk->config_lock); 573 } 574 575 static void virtblk_config_changed(struct virtio_device *vdev) 576 { 577 struct virtio_blk *vblk = vdev->priv; 578 579 queue_work(virtblk_wq, &vblk->config_work); 580 } 581 582 static int init_vq(struct virtio_blk *vblk) 583 { 584 int err = 0; 585 586 /* We expect one virtqueue, for output. */ 587 vblk->vq = virtio_find_single_vq(vblk->vdev, virtblk_done, "requests"); 588 if (IS_ERR(vblk->vq)) 589 err = PTR_ERR(vblk->vq); 590 591 return err; 592 } 593 594 /* 595 * Legacy naming scheme used for virtio devices. We are stuck with it for 596 * virtio blk but don't ever use it for any new driver. 597 */ 598 static int virtblk_name_format(char *prefix, int index, char *buf, int buflen) 599 { 600 const int base = 'z' - 'a' + 1; 601 char *begin = buf + strlen(prefix); 602 char *end = buf + buflen; 603 char *p; 604 int unit; 605 606 p = end - 1; 607 *p = '\0'; 608 unit = base; 609 do { 610 if (p == begin) 611 return -EINVAL; 612 *--p = 'a' + (index % unit); 613 index = (index / unit) - 1; 614 } while (index >= 0); 615 616 memmove(begin, p, end - p); 617 memcpy(buf, prefix, strlen(prefix)); 618 619 return 0; 620 } 621 622 static int virtblk_get_cache_mode(struct virtio_device *vdev) 623 { 624 u8 writeback; 625 int err; 626 627 err = virtio_config_val(vdev, VIRTIO_BLK_F_CONFIG_WCE, 628 offsetof(struct virtio_blk_config, wce), 629 &writeback); 630 if (err) 631 writeback = virtio_has_feature(vdev, VIRTIO_BLK_F_WCE); 632 633 return writeback; 634 } 635 636 static void virtblk_update_cache_mode(struct virtio_device *vdev) 637 { 638 u8 writeback = virtblk_get_cache_mode(vdev); 639 struct virtio_blk *vblk = vdev->priv; 640 641 if (writeback) 642 blk_queue_flush(vblk->disk->queue, REQ_FLUSH); 643 else 644 blk_queue_flush(vblk->disk->queue, 0); 645 646 revalidate_disk(vblk->disk); 647 } 648 649 static const char *const virtblk_cache_types[] = { 650 "write through", "write back" 651 }; 652 653 static ssize_t 654 virtblk_cache_type_store(struct device *dev, struct device_attribute *attr, 655 const char *buf, size_t count) 656 { 657 struct gendisk *disk = dev_to_disk(dev); 658 struct virtio_blk *vblk = disk->private_data; 659 struct virtio_device *vdev = vblk->vdev; 660 int i; 661 u8 writeback; 662 663 BUG_ON(!virtio_has_feature(vblk->vdev, VIRTIO_BLK_F_CONFIG_WCE)); 664 for (i = ARRAY_SIZE(virtblk_cache_types); --i >= 0; ) 665 if (sysfs_streq(buf, virtblk_cache_types[i])) 666 break; 667 668 if (i < 0) 669 return -EINVAL; 670 671 writeback = i; 672 vdev->config->set(vdev, 673 offsetof(struct virtio_blk_config, wce), 674 &writeback, sizeof(writeback)); 675 676 virtblk_update_cache_mode(vdev); 677 return count; 678 } 679 680 static ssize_t 681 virtblk_cache_type_show(struct device *dev, struct device_attribute *attr, 682 char *buf) 683 { 684 struct gendisk *disk = dev_to_disk(dev); 685 struct virtio_blk *vblk = disk->private_data; 686 u8 writeback = virtblk_get_cache_mode(vblk->vdev); 687 688 BUG_ON(writeback >= ARRAY_SIZE(virtblk_cache_types)); 689 return snprintf(buf, 40, "%s\n", virtblk_cache_types[writeback]); 690 } 691 692 static const struct device_attribute dev_attr_cache_type_ro = 693 __ATTR(cache_type, S_IRUGO, 694 virtblk_cache_type_show, NULL); 695 static const struct device_attribute dev_attr_cache_type_rw = 696 __ATTR(cache_type, S_IRUGO|S_IWUSR, 697 virtblk_cache_type_show, virtblk_cache_type_store); 698 699 static int __devinit virtblk_probe(struct virtio_device *vdev) 700 { 701 struct virtio_blk *vblk; 702 struct request_queue *q; 703 int err, index; 704 int pool_size; 705 706 u64 cap; 707 u32 v, blk_size, sg_elems, opt_io_size; 708 u16 min_io_size; 709 u8 physical_block_exp, alignment_offset; 710 711 err = ida_simple_get(&vd_index_ida, 0, minor_to_index(1 << MINORBITS), 712 GFP_KERNEL); 713 if (err < 0) 714 goto out; 715 index = err; 716 717 /* We need to know how many segments before we allocate. */ 718 err = virtio_config_val(vdev, VIRTIO_BLK_F_SEG_MAX, 719 offsetof(struct virtio_blk_config, seg_max), 720 &sg_elems); 721 722 /* We need at least one SG element, whatever they say. */ 723 if (err || !sg_elems) 724 sg_elems = 1; 725 726 /* We need an extra sg elements at head and tail. */ 727 sg_elems += 2; 728 vdev->priv = vblk = kmalloc(sizeof(*vblk) + 729 sizeof(vblk->sg[0]) * sg_elems, GFP_KERNEL); 730 if (!vblk) { 731 err = -ENOMEM; 732 goto out_free_index; 733 } 734 735 init_waitqueue_head(&vblk->queue_wait); 736 vblk->vdev = vdev; 737 vblk->sg_elems = sg_elems; 738 sg_init_table(vblk->sg, vblk->sg_elems); 739 mutex_init(&vblk->config_lock); 740 741 INIT_WORK(&vblk->config_work, virtblk_config_changed_work); 742 vblk->config_enable = true; 743 744 err = init_vq(vblk); 745 if (err) 746 goto out_free_vblk; 747 748 pool_size = sizeof(struct virtblk_req); 749 if (use_bio) 750 pool_size += sizeof(struct scatterlist) * sg_elems; 751 vblk->pool = mempool_create_kmalloc_pool(1, pool_size); 752 if (!vblk->pool) { 753 err = -ENOMEM; 754 goto out_free_vq; 755 } 756 757 /* FIXME: How many partitions? How long is a piece of string? */ 758 vblk->disk = alloc_disk(1 << PART_BITS); 759 if (!vblk->disk) { 760 err = -ENOMEM; 761 goto out_mempool; 762 } 763 764 q = vblk->disk->queue = blk_init_queue(virtblk_request, NULL); 765 if (!q) { 766 err = -ENOMEM; 767 goto out_put_disk; 768 } 769 770 if (use_bio) 771 blk_queue_make_request(q, virtblk_make_request); 772 q->queuedata = vblk; 773 774 virtblk_name_format("vd", index, vblk->disk->disk_name, DISK_NAME_LEN); 775 776 vblk->disk->major = major; 777 vblk->disk->first_minor = index_to_minor(index); 778 vblk->disk->private_data = vblk; 779 vblk->disk->fops = &virtblk_fops; 780 vblk->disk->driverfs_dev = &vdev->dev; 781 vblk->index = index; 782 783 /* configure queue flush support */ 784 virtblk_update_cache_mode(vdev); 785 786 /* If disk is read-only in the host, the guest should obey */ 787 if (virtio_has_feature(vdev, VIRTIO_BLK_F_RO)) 788 set_disk_ro(vblk->disk, 1); 789 790 /* Host must always specify the capacity. */ 791 vdev->config->get(vdev, offsetof(struct virtio_blk_config, capacity), 792 &cap, sizeof(cap)); 793 794 /* If capacity is too big, truncate with warning. */ 795 if ((sector_t)cap != cap) { 796 dev_warn(&vdev->dev, "Capacity %llu too large: truncating\n", 797 (unsigned long long)cap); 798 cap = (sector_t)-1; 799 } 800 set_capacity(vblk->disk, cap); 801 802 /* We can handle whatever the host told us to handle. */ 803 blk_queue_max_segments(q, vblk->sg_elems-2); 804 805 /* No need to bounce any requests */ 806 blk_queue_bounce_limit(q, BLK_BOUNCE_ANY); 807 808 /* No real sector limit. */ 809 blk_queue_max_hw_sectors(q, -1U); 810 811 /* Host can optionally specify maximum segment size and number of 812 * segments. */ 813 err = virtio_config_val(vdev, VIRTIO_BLK_F_SIZE_MAX, 814 offsetof(struct virtio_blk_config, size_max), 815 &v); 816 if (!err) 817 blk_queue_max_segment_size(q, v); 818 else 819 blk_queue_max_segment_size(q, -1U); 820 821 /* Host can optionally specify the block size of the device */ 822 err = virtio_config_val(vdev, VIRTIO_BLK_F_BLK_SIZE, 823 offsetof(struct virtio_blk_config, blk_size), 824 &blk_size); 825 if (!err) 826 blk_queue_logical_block_size(q, blk_size); 827 else 828 blk_size = queue_logical_block_size(q); 829 830 /* Use topology information if available */ 831 err = virtio_config_val(vdev, VIRTIO_BLK_F_TOPOLOGY, 832 offsetof(struct virtio_blk_config, physical_block_exp), 833 &physical_block_exp); 834 if (!err && physical_block_exp) 835 blk_queue_physical_block_size(q, 836 blk_size * (1 << physical_block_exp)); 837 838 err = virtio_config_val(vdev, VIRTIO_BLK_F_TOPOLOGY, 839 offsetof(struct virtio_blk_config, alignment_offset), 840 &alignment_offset); 841 if (!err && alignment_offset) 842 blk_queue_alignment_offset(q, blk_size * alignment_offset); 843 844 err = virtio_config_val(vdev, VIRTIO_BLK_F_TOPOLOGY, 845 offsetof(struct virtio_blk_config, min_io_size), 846 &min_io_size); 847 if (!err && min_io_size) 848 blk_queue_io_min(q, blk_size * min_io_size); 849 850 err = virtio_config_val(vdev, VIRTIO_BLK_F_TOPOLOGY, 851 offsetof(struct virtio_blk_config, opt_io_size), 852 &opt_io_size); 853 if (!err && opt_io_size) 854 blk_queue_io_opt(q, blk_size * opt_io_size); 855 856 add_disk(vblk->disk); 857 err = device_create_file(disk_to_dev(vblk->disk), &dev_attr_serial); 858 if (err) 859 goto out_del_disk; 860 861 if (virtio_has_feature(vdev, VIRTIO_BLK_F_CONFIG_WCE)) 862 err = device_create_file(disk_to_dev(vblk->disk), 863 &dev_attr_cache_type_rw); 864 else 865 err = device_create_file(disk_to_dev(vblk->disk), 866 &dev_attr_cache_type_ro); 867 if (err) 868 goto out_del_disk; 869 return 0; 870 871 out_del_disk: 872 del_gendisk(vblk->disk); 873 blk_cleanup_queue(vblk->disk->queue); 874 out_put_disk: 875 put_disk(vblk->disk); 876 out_mempool: 877 mempool_destroy(vblk->pool); 878 out_free_vq: 879 vdev->config->del_vqs(vdev); 880 out_free_vblk: 881 kfree(vblk); 882 out_free_index: 883 ida_simple_remove(&vd_index_ida, index); 884 out: 885 return err; 886 } 887 888 static void __devexit virtblk_remove(struct virtio_device *vdev) 889 { 890 struct virtio_blk *vblk = vdev->priv; 891 int index = vblk->index; 892 893 /* Prevent config work handler from accessing the device. */ 894 mutex_lock(&vblk->config_lock); 895 vblk->config_enable = false; 896 mutex_unlock(&vblk->config_lock); 897 898 del_gendisk(vblk->disk); 899 blk_cleanup_queue(vblk->disk->queue); 900 901 /* Stop all the virtqueues. */ 902 vdev->config->reset(vdev); 903 904 flush_work(&vblk->config_work); 905 906 put_disk(vblk->disk); 907 mempool_destroy(vblk->pool); 908 vdev->config->del_vqs(vdev); 909 kfree(vblk); 910 ida_simple_remove(&vd_index_ida, index); 911 } 912 913 #ifdef CONFIG_PM 914 static int virtblk_freeze(struct virtio_device *vdev) 915 { 916 struct virtio_blk *vblk = vdev->priv; 917 918 /* Ensure we don't receive any more interrupts */ 919 vdev->config->reset(vdev); 920 921 /* Prevent config work handler from accessing the device. */ 922 mutex_lock(&vblk->config_lock); 923 vblk->config_enable = false; 924 mutex_unlock(&vblk->config_lock); 925 926 flush_work(&vblk->config_work); 927 928 spin_lock_irq(vblk->disk->queue->queue_lock); 929 blk_stop_queue(vblk->disk->queue); 930 spin_unlock_irq(vblk->disk->queue->queue_lock); 931 blk_sync_queue(vblk->disk->queue); 932 933 vdev->config->del_vqs(vdev); 934 return 0; 935 } 936 937 static int virtblk_restore(struct virtio_device *vdev) 938 { 939 struct virtio_blk *vblk = vdev->priv; 940 int ret; 941 942 vblk->config_enable = true; 943 ret = init_vq(vdev->priv); 944 if (!ret) { 945 spin_lock_irq(vblk->disk->queue->queue_lock); 946 blk_start_queue(vblk->disk->queue); 947 spin_unlock_irq(vblk->disk->queue->queue_lock); 948 } 949 return ret; 950 } 951 #endif 952 953 static const struct virtio_device_id id_table[] = { 954 { VIRTIO_ID_BLOCK, VIRTIO_DEV_ANY_ID }, 955 { 0 }, 956 }; 957 958 static unsigned int features[] = { 959 VIRTIO_BLK_F_SEG_MAX, VIRTIO_BLK_F_SIZE_MAX, VIRTIO_BLK_F_GEOMETRY, 960 VIRTIO_BLK_F_RO, VIRTIO_BLK_F_BLK_SIZE, VIRTIO_BLK_F_SCSI, 961 VIRTIO_BLK_F_WCE, VIRTIO_BLK_F_TOPOLOGY, VIRTIO_BLK_F_CONFIG_WCE 962 }; 963 964 /* 965 * virtio_blk causes spurious section mismatch warning by 966 * simultaneously referring to a __devinit and a __devexit function. 967 * Use __refdata to avoid this warning. 968 */ 969 static struct virtio_driver __refdata virtio_blk = { 970 .feature_table = features, 971 .feature_table_size = ARRAY_SIZE(features), 972 .driver.name = KBUILD_MODNAME, 973 .driver.owner = THIS_MODULE, 974 .id_table = id_table, 975 .probe = virtblk_probe, 976 .remove = __devexit_p(virtblk_remove), 977 .config_changed = virtblk_config_changed, 978 #ifdef CONFIG_PM 979 .freeze = virtblk_freeze, 980 .restore = virtblk_restore, 981 #endif 982 }; 983 984 static int __init init(void) 985 { 986 int error; 987 988 virtblk_wq = alloc_workqueue("virtio-blk", 0, 0); 989 if (!virtblk_wq) 990 return -ENOMEM; 991 992 major = register_blkdev(0, "virtblk"); 993 if (major < 0) { 994 error = major; 995 goto out_destroy_workqueue; 996 } 997 998 error = register_virtio_driver(&virtio_blk); 999 if (error) 1000 goto out_unregister_blkdev; 1001 return 0; 1002 1003 out_unregister_blkdev: 1004 unregister_blkdev(major, "virtblk"); 1005 out_destroy_workqueue: 1006 destroy_workqueue(virtblk_wq); 1007 return error; 1008 } 1009 1010 static void __exit fini(void) 1011 { 1012 unregister_blkdev(major, "virtblk"); 1013 unregister_virtio_driver(&virtio_blk); 1014 destroy_workqueue(virtblk_wq); 1015 } 1016 module_init(init); 1017 module_exit(fini); 1018 1019 MODULE_DEVICE_TABLE(virtio, id_table); 1020 MODULE_DESCRIPTION("Virtio block driver"); 1021 MODULE_LICENSE("GPL"); 1022