1 /* 2 * bsg.c - block layer implementation of the sg v4 interface 3 * 4 * Copyright (C) 2004 Jens Axboe <axboe@suse.de> SUSE Labs 5 * Copyright (C) 2004 Peter M. Jones <pjones@redhat.com> 6 * 7 * This file is subject to the terms and conditions of the GNU General Public 8 * License version 2. See the file "COPYING" in the main directory of this 9 * archive for more details. 10 * 11 */ 12 #include <linux/module.h> 13 #include <linux/init.h> 14 #include <linux/file.h> 15 #include <linux/blkdev.h> 16 #include <linux/poll.h> 17 #include <linux/cdev.h> 18 #include <linux/jiffies.h> 19 #include <linux/percpu.h> 20 #include <linux/uio.h> 21 #include <linux/idr.h> 22 #include <linux/bsg.h> 23 #include <linux/slab.h> 24 25 #include <scsi/scsi.h> 26 #include <scsi/scsi_ioctl.h> 27 #include <scsi/scsi_cmnd.h> 28 #include <scsi/scsi_device.h> 29 #include <scsi/scsi_driver.h> 30 #include <scsi/sg.h> 31 32 #define BSG_DESCRIPTION "Block layer SCSI generic (bsg) driver" 33 #define BSG_VERSION "0.4" 34 35 #define bsg_dbg(bd, fmt, ...) \ 36 pr_debug("%s: " fmt, (bd)->name, ##__VA_ARGS__) 37 38 struct bsg_device { 39 struct request_queue *queue; 40 spinlock_t lock; 41 struct list_head busy_list; 42 struct list_head done_list; 43 struct hlist_node dev_list; 44 atomic_t ref_count; 45 int queued_cmds; 46 int done_cmds; 47 wait_queue_head_t wq_done; 48 wait_queue_head_t wq_free; 49 char name[20]; 50 int max_queue; 51 unsigned long flags; 52 }; 53 54 enum { 55 BSG_F_BLOCK = 1, 56 }; 57 58 #define BSG_DEFAULT_CMDS 64 59 #define BSG_MAX_DEVS 32768 60 61 static DEFINE_MUTEX(bsg_mutex); 62 static DEFINE_IDR(bsg_minor_idr); 63 64 #define BSG_LIST_ARRAY_SIZE 8 65 static struct hlist_head bsg_device_list[BSG_LIST_ARRAY_SIZE]; 66 67 static struct class *bsg_class; 68 static int bsg_major; 69 70 static struct kmem_cache *bsg_cmd_cachep; 71 72 /* 73 * our internal command type 74 */ 75 struct bsg_command { 76 struct bsg_device *bd; 77 struct list_head list; 78 struct request *rq; 79 struct bio *bio; 80 struct bio *bidi_bio; 81 int err; 82 struct sg_io_v4 hdr; 83 }; 84 85 static void bsg_free_command(struct bsg_command *bc) 86 { 87 struct bsg_device *bd = bc->bd; 88 unsigned long flags; 89 90 kmem_cache_free(bsg_cmd_cachep, bc); 91 92 spin_lock_irqsave(&bd->lock, flags); 93 bd->queued_cmds--; 94 spin_unlock_irqrestore(&bd->lock, flags); 95 96 wake_up(&bd->wq_free); 97 } 98 99 static struct bsg_command *bsg_alloc_command(struct bsg_device *bd) 100 { 101 struct bsg_command *bc = ERR_PTR(-EINVAL); 102 103 spin_lock_irq(&bd->lock); 104 105 if (bd->queued_cmds >= bd->max_queue) 106 goto out; 107 108 bd->queued_cmds++; 109 spin_unlock_irq(&bd->lock); 110 111 bc = kmem_cache_zalloc(bsg_cmd_cachep, GFP_KERNEL); 112 if (unlikely(!bc)) { 113 spin_lock_irq(&bd->lock); 114 bd->queued_cmds--; 115 bc = ERR_PTR(-ENOMEM); 116 goto out; 117 } 118 119 bc->bd = bd; 120 INIT_LIST_HEAD(&bc->list); 121 bsg_dbg(bd, "returning free cmd %p\n", bc); 122 return bc; 123 out: 124 spin_unlock_irq(&bd->lock); 125 return bc; 126 } 127 128 static inline struct hlist_head *bsg_dev_idx_hash(int index) 129 { 130 return &bsg_device_list[index & (BSG_LIST_ARRAY_SIZE - 1)]; 131 } 132 133 static int blk_fill_sgv4_hdr_rq(struct request_queue *q, struct request *rq, 134 struct sg_io_v4 *hdr, struct bsg_device *bd, 135 fmode_t mode) 136 { 137 struct scsi_request *req = scsi_req(rq); 138 139 if (hdr->request_len > BLK_MAX_CDB) { 140 req->cmd = kzalloc(hdr->request_len, GFP_KERNEL); 141 if (!req->cmd) 142 return -ENOMEM; 143 } 144 145 if (copy_from_user(req->cmd, (void __user *)(unsigned long)hdr->request, 146 hdr->request_len)) 147 return -EFAULT; 148 149 if (hdr->subprotocol == BSG_SUB_PROTOCOL_SCSI_CMD) { 150 if (blk_verify_command(req->cmd, mode)) 151 return -EPERM; 152 } else if (!capable(CAP_SYS_RAWIO)) 153 return -EPERM; 154 155 /* 156 * fill in request structure 157 */ 158 req->cmd_len = hdr->request_len; 159 160 rq->timeout = msecs_to_jiffies(hdr->timeout); 161 if (!rq->timeout) 162 rq->timeout = q->sg_timeout; 163 if (!rq->timeout) 164 rq->timeout = BLK_DEFAULT_SG_TIMEOUT; 165 if (rq->timeout < BLK_MIN_SG_TIMEOUT) 166 rq->timeout = BLK_MIN_SG_TIMEOUT; 167 168 return 0; 169 } 170 171 /* 172 * Check if sg_io_v4 from user is allowed and valid 173 */ 174 static int 175 bsg_validate_sgv4_hdr(struct sg_io_v4 *hdr, int *op) 176 { 177 int ret = 0; 178 179 if (hdr->guard != 'Q') 180 return -EINVAL; 181 182 switch (hdr->protocol) { 183 case BSG_PROTOCOL_SCSI: 184 switch (hdr->subprotocol) { 185 case BSG_SUB_PROTOCOL_SCSI_CMD: 186 case BSG_SUB_PROTOCOL_SCSI_TRANSPORT: 187 break; 188 default: 189 ret = -EINVAL; 190 } 191 break; 192 default: 193 ret = -EINVAL; 194 } 195 196 *op = hdr->dout_xfer_len ? REQ_OP_SCSI_OUT : REQ_OP_SCSI_IN; 197 return ret; 198 } 199 200 /* 201 * map sg_io_v4 to a request. 202 */ 203 static struct request * 204 bsg_map_hdr(struct bsg_device *bd, struct sg_io_v4 *hdr, fmode_t mode) 205 { 206 struct request_queue *q = bd->queue; 207 struct request *rq, *next_rq = NULL; 208 int ret; 209 unsigned int op, dxfer_len; 210 void __user *dxferp = NULL; 211 struct bsg_class_device *bcd = &q->bsg_dev; 212 213 /* if the LLD has been removed then the bsg_unregister_queue will 214 * eventually be called and the class_dev was freed, so we can no 215 * longer use this request_queue. Return no such address. 216 */ 217 if (!bcd->class_dev) 218 return ERR_PTR(-ENXIO); 219 220 bsg_dbg(bd, "map hdr %llx/%u %llx/%u\n", 221 (unsigned long long) hdr->dout_xferp, 222 hdr->dout_xfer_len, (unsigned long long) hdr->din_xferp, 223 hdr->din_xfer_len); 224 225 ret = bsg_validate_sgv4_hdr(hdr, &op); 226 if (ret) 227 return ERR_PTR(ret); 228 229 /* 230 * map scatter-gather elements separately and string them to request 231 */ 232 rq = blk_get_request(q, op, GFP_KERNEL); 233 if (IS_ERR(rq)) 234 return rq; 235 236 ret = blk_fill_sgv4_hdr_rq(q, rq, hdr, bd, mode); 237 if (ret) 238 goto out; 239 240 if (op == REQ_OP_SCSI_OUT && hdr->din_xfer_len) { 241 if (!test_bit(QUEUE_FLAG_BIDI, &q->queue_flags)) { 242 ret = -EOPNOTSUPP; 243 goto out; 244 } 245 246 next_rq = blk_get_request(q, REQ_OP_SCSI_IN, GFP_KERNEL); 247 if (IS_ERR(next_rq)) { 248 ret = PTR_ERR(next_rq); 249 next_rq = NULL; 250 goto out; 251 } 252 rq->next_rq = next_rq; 253 254 dxferp = (void __user *)(unsigned long)hdr->din_xferp; 255 ret = blk_rq_map_user(q, next_rq, NULL, dxferp, 256 hdr->din_xfer_len, GFP_KERNEL); 257 if (ret) 258 goto out; 259 } 260 261 if (hdr->dout_xfer_len) { 262 dxfer_len = hdr->dout_xfer_len; 263 dxferp = (void __user *)(unsigned long)hdr->dout_xferp; 264 } else if (hdr->din_xfer_len) { 265 dxfer_len = hdr->din_xfer_len; 266 dxferp = (void __user *)(unsigned long)hdr->din_xferp; 267 } else 268 dxfer_len = 0; 269 270 if (dxfer_len) { 271 ret = blk_rq_map_user(q, rq, NULL, dxferp, dxfer_len, 272 GFP_KERNEL); 273 if (ret) 274 goto out; 275 } 276 277 return rq; 278 out: 279 scsi_req_free_cmd(scsi_req(rq)); 280 blk_put_request(rq); 281 if (next_rq) { 282 blk_rq_unmap_user(next_rq->bio); 283 blk_put_request(next_rq); 284 } 285 return ERR_PTR(ret); 286 } 287 288 /* 289 * async completion call-back from the block layer, when scsi/ide/whatever 290 * calls end_that_request_last() on a request 291 */ 292 static void bsg_rq_end_io(struct request *rq, blk_status_t status) 293 { 294 struct bsg_command *bc = rq->end_io_data; 295 struct bsg_device *bd = bc->bd; 296 unsigned long flags; 297 298 bsg_dbg(bd, "finished rq %p bc %p, bio %p\n", 299 rq, bc, bc->bio); 300 301 bc->hdr.duration = jiffies_to_msecs(jiffies - bc->hdr.duration); 302 303 spin_lock_irqsave(&bd->lock, flags); 304 list_move_tail(&bc->list, &bd->done_list); 305 bd->done_cmds++; 306 spin_unlock_irqrestore(&bd->lock, flags); 307 308 wake_up(&bd->wq_done); 309 } 310 311 /* 312 * do final setup of a 'bc' and submit the matching 'rq' to the block 313 * layer for io 314 */ 315 static void bsg_add_command(struct bsg_device *bd, struct request_queue *q, 316 struct bsg_command *bc, struct request *rq) 317 { 318 int at_head = (0 == (bc->hdr.flags & BSG_FLAG_Q_AT_TAIL)); 319 320 /* 321 * add bc command to busy queue and submit rq for io 322 */ 323 bc->rq = rq; 324 bc->bio = rq->bio; 325 if (rq->next_rq) 326 bc->bidi_bio = rq->next_rq->bio; 327 bc->hdr.duration = jiffies; 328 spin_lock_irq(&bd->lock); 329 list_add_tail(&bc->list, &bd->busy_list); 330 spin_unlock_irq(&bd->lock); 331 332 bsg_dbg(bd, "queueing rq %p, bc %p\n", rq, bc); 333 334 rq->end_io_data = bc; 335 blk_execute_rq_nowait(q, NULL, rq, at_head, bsg_rq_end_io); 336 } 337 338 static struct bsg_command *bsg_next_done_cmd(struct bsg_device *bd) 339 { 340 struct bsg_command *bc = NULL; 341 342 spin_lock_irq(&bd->lock); 343 if (bd->done_cmds) { 344 bc = list_first_entry(&bd->done_list, struct bsg_command, list); 345 list_del(&bc->list); 346 bd->done_cmds--; 347 } 348 spin_unlock_irq(&bd->lock); 349 350 return bc; 351 } 352 353 /* 354 * Get a finished command from the done list 355 */ 356 static struct bsg_command *bsg_get_done_cmd(struct bsg_device *bd) 357 { 358 struct bsg_command *bc; 359 int ret; 360 361 do { 362 bc = bsg_next_done_cmd(bd); 363 if (bc) 364 break; 365 366 if (!test_bit(BSG_F_BLOCK, &bd->flags)) { 367 bc = ERR_PTR(-EAGAIN); 368 break; 369 } 370 371 ret = wait_event_interruptible(bd->wq_done, bd->done_cmds); 372 if (ret) { 373 bc = ERR_PTR(-ERESTARTSYS); 374 break; 375 } 376 } while (1); 377 378 bsg_dbg(bd, "returning done %p\n", bc); 379 380 return bc; 381 } 382 383 static int blk_complete_sgv4_hdr_rq(struct request *rq, struct sg_io_v4 *hdr, 384 struct bio *bio, struct bio *bidi_bio) 385 { 386 struct scsi_request *req = scsi_req(rq); 387 int ret = 0; 388 389 pr_debug("rq %p bio %p 0x%x\n", rq, bio, req->result); 390 /* 391 * fill in all the output members 392 */ 393 hdr->device_status = req->result & 0xff; 394 hdr->transport_status = host_byte(req->result); 395 hdr->driver_status = driver_byte(req->result); 396 hdr->info = 0; 397 if (hdr->device_status || hdr->transport_status || hdr->driver_status) 398 hdr->info |= SG_INFO_CHECK; 399 hdr->response_len = 0; 400 401 if (req->sense_len && hdr->response) { 402 int len = min_t(unsigned int, hdr->max_response_len, 403 req->sense_len); 404 405 ret = copy_to_user((void __user *)(unsigned long)hdr->response, 406 req->sense, len); 407 if (!ret) 408 hdr->response_len = len; 409 else 410 ret = -EFAULT; 411 } 412 413 if (rq->next_rq) { 414 hdr->dout_resid = req->resid_len; 415 hdr->din_resid = scsi_req(rq->next_rq)->resid_len; 416 blk_rq_unmap_user(bidi_bio); 417 blk_put_request(rq->next_rq); 418 } else if (rq_data_dir(rq) == READ) 419 hdr->din_resid = req->resid_len; 420 else 421 hdr->dout_resid = req->resid_len; 422 423 /* 424 * If the request generated a negative error number, return it 425 * (providing we aren't already returning an error); if it's 426 * just a protocol response (i.e. non negative), that gets 427 * processed above. 428 */ 429 if (!ret && req->result < 0) 430 ret = req->result; 431 432 blk_rq_unmap_user(bio); 433 scsi_req_free_cmd(req); 434 blk_put_request(rq); 435 436 return ret; 437 } 438 439 static bool bsg_complete(struct bsg_device *bd) 440 { 441 bool ret = false; 442 bool spin; 443 444 do { 445 spin_lock_irq(&bd->lock); 446 447 BUG_ON(bd->done_cmds > bd->queued_cmds); 448 449 /* 450 * All commands consumed. 451 */ 452 if (bd->done_cmds == bd->queued_cmds) 453 ret = true; 454 455 spin = !test_bit(BSG_F_BLOCK, &bd->flags); 456 457 spin_unlock_irq(&bd->lock); 458 } while (!ret && spin); 459 460 return ret; 461 } 462 463 static int bsg_complete_all_commands(struct bsg_device *bd) 464 { 465 struct bsg_command *bc; 466 int ret, tret; 467 468 bsg_dbg(bd, "entered\n"); 469 470 /* 471 * wait for all commands to complete 472 */ 473 io_wait_event(bd->wq_done, bsg_complete(bd)); 474 475 /* 476 * discard done commands 477 */ 478 ret = 0; 479 do { 480 spin_lock_irq(&bd->lock); 481 if (!bd->queued_cmds) { 482 spin_unlock_irq(&bd->lock); 483 break; 484 } 485 spin_unlock_irq(&bd->lock); 486 487 bc = bsg_get_done_cmd(bd); 488 if (IS_ERR(bc)) 489 break; 490 491 tret = blk_complete_sgv4_hdr_rq(bc->rq, &bc->hdr, bc->bio, 492 bc->bidi_bio); 493 if (!ret) 494 ret = tret; 495 496 bsg_free_command(bc); 497 } while (1); 498 499 return ret; 500 } 501 502 static int 503 __bsg_read(char __user *buf, size_t count, struct bsg_device *bd, 504 const struct iovec *iov, ssize_t *bytes_read) 505 { 506 struct bsg_command *bc; 507 int nr_commands, ret; 508 509 if (count % sizeof(struct sg_io_v4)) 510 return -EINVAL; 511 512 ret = 0; 513 nr_commands = count / sizeof(struct sg_io_v4); 514 while (nr_commands) { 515 bc = bsg_get_done_cmd(bd); 516 if (IS_ERR(bc)) { 517 ret = PTR_ERR(bc); 518 break; 519 } 520 521 /* 522 * this is the only case where we need to copy data back 523 * after completing the request. so do that here, 524 * bsg_complete_work() cannot do that for us 525 */ 526 ret = blk_complete_sgv4_hdr_rq(bc->rq, &bc->hdr, bc->bio, 527 bc->bidi_bio); 528 529 if (copy_to_user(buf, &bc->hdr, sizeof(bc->hdr))) 530 ret = -EFAULT; 531 532 bsg_free_command(bc); 533 534 if (ret) 535 break; 536 537 buf += sizeof(struct sg_io_v4); 538 *bytes_read += sizeof(struct sg_io_v4); 539 nr_commands--; 540 } 541 542 return ret; 543 } 544 545 static inline void bsg_set_block(struct bsg_device *bd, struct file *file) 546 { 547 if (file->f_flags & O_NONBLOCK) 548 clear_bit(BSG_F_BLOCK, &bd->flags); 549 else 550 set_bit(BSG_F_BLOCK, &bd->flags); 551 } 552 553 /* 554 * Check if the error is a "real" error that we should return. 555 */ 556 static inline int err_block_err(int ret) 557 { 558 if (ret && ret != -ENOSPC && ret != -ENODATA && ret != -EAGAIN) 559 return 1; 560 561 return 0; 562 } 563 564 static ssize_t 565 bsg_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) 566 { 567 struct bsg_device *bd = file->private_data; 568 int ret; 569 ssize_t bytes_read; 570 571 bsg_dbg(bd, "read %zd bytes\n", count); 572 573 bsg_set_block(bd, file); 574 575 bytes_read = 0; 576 ret = __bsg_read(buf, count, bd, NULL, &bytes_read); 577 *ppos = bytes_read; 578 579 if (!bytes_read || err_block_err(ret)) 580 bytes_read = ret; 581 582 return bytes_read; 583 } 584 585 static int __bsg_write(struct bsg_device *bd, const char __user *buf, 586 size_t count, ssize_t *bytes_written, fmode_t mode) 587 { 588 struct bsg_command *bc; 589 struct request *rq; 590 int ret, nr_commands; 591 592 if (count % sizeof(struct sg_io_v4)) 593 return -EINVAL; 594 595 nr_commands = count / sizeof(struct sg_io_v4); 596 rq = NULL; 597 bc = NULL; 598 ret = 0; 599 while (nr_commands) { 600 struct request_queue *q = bd->queue; 601 602 bc = bsg_alloc_command(bd); 603 if (IS_ERR(bc)) { 604 ret = PTR_ERR(bc); 605 bc = NULL; 606 break; 607 } 608 609 if (copy_from_user(&bc->hdr, buf, sizeof(bc->hdr))) { 610 ret = -EFAULT; 611 break; 612 } 613 614 /* 615 * get a request, fill in the blanks, and add to request queue 616 */ 617 rq = bsg_map_hdr(bd, &bc->hdr, mode); 618 if (IS_ERR(rq)) { 619 ret = PTR_ERR(rq); 620 rq = NULL; 621 break; 622 } 623 624 bsg_add_command(bd, q, bc, rq); 625 bc = NULL; 626 rq = NULL; 627 nr_commands--; 628 buf += sizeof(struct sg_io_v4); 629 *bytes_written += sizeof(struct sg_io_v4); 630 } 631 632 if (bc) 633 bsg_free_command(bc); 634 635 return ret; 636 } 637 638 static ssize_t 639 bsg_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) 640 { 641 struct bsg_device *bd = file->private_data; 642 ssize_t bytes_written; 643 int ret; 644 645 bsg_dbg(bd, "write %zd bytes\n", count); 646 647 if (unlikely(uaccess_kernel())) 648 return -EINVAL; 649 650 bsg_set_block(bd, file); 651 652 bytes_written = 0; 653 ret = __bsg_write(bd, buf, count, &bytes_written, file->f_mode); 654 655 *ppos = bytes_written; 656 657 /* 658 * return bytes written on non-fatal errors 659 */ 660 if (!bytes_written || err_block_err(ret)) 661 bytes_written = ret; 662 663 bsg_dbg(bd, "returning %zd\n", bytes_written); 664 return bytes_written; 665 } 666 667 static struct bsg_device *bsg_alloc_device(void) 668 { 669 struct bsg_device *bd; 670 671 bd = kzalloc(sizeof(struct bsg_device), GFP_KERNEL); 672 if (unlikely(!bd)) 673 return NULL; 674 675 spin_lock_init(&bd->lock); 676 677 bd->max_queue = BSG_DEFAULT_CMDS; 678 679 INIT_LIST_HEAD(&bd->busy_list); 680 INIT_LIST_HEAD(&bd->done_list); 681 INIT_HLIST_NODE(&bd->dev_list); 682 683 init_waitqueue_head(&bd->wq_free); 684 init_waitqueue_head(&bd->wq_done); 685 return bd; 686 } 687 688 static void bsg_kref_release_function(struct kref *kref) 689 { 690 struct bsg_class_device *bcd = 691 container_of(kref, struct bsg_class_device, ref); 692 struct device *parent = bcd->parent; 693 694 if (bcd->release) 695 bcd->release(bcd->parent); 696 697 put_device(parent); 698 } 699 700 static int bsg_put_device(struct bsg_device *bd) 701 { 702 int ret = 0, do_free; 703 struct request_queue *q = bd->queue; 704 705 mutex_lock(&bsg_mutex); 706 707 do_free = atomic_dec_and_test(&bd->ref_count); 708 if (!do_free) { 709 mutex_unlock(&bsg_mutex); 710 goto out; 711 } 712 713 hlist_del(&bd->dev_list); 714 mutex_unlock(&bsg_mutex); 715 716 bsg_dbg(bd, "tearing down\n"); 717 718 /* 719 * close can always block 720 */ 721 set_bit(BSG_F_BLOCK, &bd->flags); 722 723 /* 724 * correct error detection baddies here again. it's the responsibility 725 * of the app to properly reap commands before close() if it wants 726 * fool-proof error detection 727 */ 728 ret = bsg_complete_all_commands(bd); 729 730 kfree(bd); 731 out: 732 kref_put(&q->bsg_dev.ref, bsg_kref_release_function); 733 if (do_free) 734 blk_put_queue(q); 735 return ret; 736 } 737 738 static struct bsg_device *bsg_add_device(struct inode *inode, 739 struct request_queue *rq, 740 struct file *file) 741 { 742 struct bsg_device *bd; 743 unsigned char buf[32]; 744 745 if (!blk_queue_scsi_passthrough(rq)) { 746 WARN_ONCE(true, "Attempt to register a non-SCSI queue\n"); 747 return ERR_PTR(-EINVAL); 748 } 749 750 if (!blk_get_queue(rq)) 751 return ERR_PTR(-ENXIO); 752 753 bd = bsg_alloc_device(); 754 if (!bd) { 755 blk_put_queue(rq); 756 return ERR_PTR(-ENOMEM); 757 } 758 759 bd->queue = rq; 760 761 bsg_set_block(bd, file); 762 763 atomic_set(&bd->ref_count, 1); 764 mutex_lock(&bsg_mutex); 765 hlist_add_head(&bd->dev_list, bsg_dev_idx_hash(iminor(inode))); 766 767 strncpy(bd->name, dev_name(rq->bsg_dev.class_dev), sizeof(bd->name) - 1); 768 bsg_dbg(bd, "bound to <%s>, max queue %d\n", 769 format_dev_t(buf, inode->i_rdev), bd->max_queue); 770 771 mutex_unlock(&bsg_mutex); 772 return bd; 773 } 774 775 static struct bsg_device *__bsg_get_device(int minor, struct request_queue *q) 776 { 777 struct bsg_device *bd; 778 779 mutex_lock(&bsg_mutex); 780 781 hlist_for_each_entry(bd, bsg_dev_idx_hash(minor), dev_list) { 782 if (bd->queue == q) { 783 atomic_inc(&bd->ref_count); 784 goto found; 785 } 786 } 787 bd = NULL; 788 found: 789 mutex_unlock(&bsg_mutex); 790 return bd; 791 } 792 793 static struct bsg_device *bsg_get_device(struct inode *inode, struct file *file) 794 { 795 struct bsg_device *bd; 796 struct bsg_class_device *bcd; 797 798 /* 799 * find the class device 800 */ 801 mutex_lock(&bsg_mutex); 802 bcd = idr_find(&bsg_minor_idr, iminor(inode)); 803 if (bcd) 804 kref_get(&bcd->ref); 805 mutex_unlock(&bsg_mutex); 806 807 if (!bcd) 808 return ERR_PTR(-ENODEV); 809 810 bd = __bsg_get_device(iminor(inode), bcd->queue); 811 if (bd) 812 return bd; 813 814 bd = bsg_add_device(inode, bcd->queue, file); 815 if (IS_ERR(bd)) 816 kref_put(&bcd->ref, bsg_kref_release_function); 817 818 return bd; 819 } 820 821 static int bsg_open(struct inode *inode, struct file *file) 822 { 823 struct bsg_device *bd; 824 825 bd = bsg_get_device(inode, file); 826 827 if (IS_ERR(bd)) 828 return PTR_ERR(bd); 829 830 file->private_data = bd; 831 return 0; 832 } 833 834 static int bsg_release(struct inode *inode, struct file *file) 835 { 836 struct bsg_device *bd = file->private_data; 837 838 file->private_data = NULL; 839 return bsg_put_device(bd); 840 } 841 842 static __poll_t bsg_poll(struct file *file, poll_table *wait) 843 { 844 struct bsg_device *bd = file->private_data; 845 __poll_t mask = 0; 846 847 poll_wait(file, &bd->wq_done, wait); 848 poll_wait(file, &bd->wq_free, wait); 849 850 spin_lock_irq(&bd->lock); 851 if (!list_empty(&bd->done_list)) 852 mask |= EPOLLIN | EPOLLRDNORM; 853 if (bd->queued_cmds < bd->max_queue) 854 mask |= EPOLLOUT; 855 spin_unlock_irq(&bd->lock); 856 857 return mask; 858 } 859 860 static long bsg_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 861 { 862 struct bsg_device *bd = file->private_data; 863 int __user *uarg = (int __user *) arg; 864 int ret; 865 866 switch (cmd) { 867 /* 868 * our own ioctls 869 */ 870 case SG_GET_COMMAND_Q: 871 return put_user(bd->max_queue, uarg); 872 case SG_SET_COMMAND_Q: { 873 int queue; 874 875 if (get_user(queue, uarg)) 876 return -EFAULT; 877 if (queue < 1) 878 return -EINVAL; 879 880 spin_lock_irq(&bd->lock); 881 bd->max_queue = queue; 882 spin_unlock_irq(&bd->lock); 883 return 0; 884 } 885 886 /* 887 * SCSI/sg ioctls 888 */ 889 case SG_GET_VERSION_NUM: 890 case SCSI_IOCTL_GET_IDLUN: 891 case SCSI_IOCTL_GET_BUS_NUMBER: 892 case SG_SET_TIMEOUT: 893 case SG_GET_TIMEOUT: 894 case SG_GET_RESERVED_SIZE: 895 case SG_SET_RESERVED_SIZE: 896 case SG_EMULATED_HOST: 897 case SCSI_IOCTL_SEND_COMMAND: { 898 void __user *uarg = (void __user *) arg; 899 return scsi_cmd_ioctl(bd->queue, NULL, file->f_mode, cmd, uarg); 900 } 901 case SG_IO: { 902 struct request *rq; 903 struct bio *bio, *bidi_bio = NULL; 904 struct sg_io_v4 hdr; 905 int at_head; 906 907 if (copy_from_user(&hdr, uarg, sizeof(hdr))) 908 return -EFAULT; 909 910 rq = bsg_map_hdr(bd, &hdr, file->f_mode); 911 if (IS_ERR(rq)) 912 return PTR_ERR(rq); 913 914 bio = rq->bio; 915 if (rq->next_rq) 916 bidi_bio = rq->next_rq->bio; 917 918 at_head = (0 == (hdr.flags & BSG_FLAG_Q_AT_TAIL)); 919 blk_execute_rq(bd->queue, NULL, rq, at_head); 920 ret = blk_complete_sgv4_hdr_rq(rq, &hdr, bio, bidi_bio); 921 922 if (copy_to_user(uarg, &hdr, sizeof(hdr))) 923 return -EFAULT; 924 925 return ret; 926 } 927 default: 928 return -ENOTTY; 929 } 930 } 931 932 static const struct file_operations bsg_fops = { 933 .read = bsg_read, 934 .write = bsg_write, 935 .poll = bsg_poll, 936 .open = bsg_open, 937 .release = bsg_release, 938 .unlocked_ioctl = bsg_ioctl, 939 .owner = THIS_MODULE, 940 .llseek = default_llseek, 941 }; 942 943 void bsg_unregister_queue(struct request_queue *q) 944 { 945 struct bsg_class_device *bcd = &q->bsg_dev; 946 947 if (!bcd->class_dev) 948 return; 949 950 mutex_lock(&bsg_mutex); 951 idr_remove(&bsg_minor_idr, bcd->minor); 952 if (q->kobj.sd) 953 sysfs_remove_link(&q->kobj, "bsg"); 954 device_unregister(bcd->class_dev); 955 bcd->class_dev = NULL; 956 kref_put(&bcd->ref, bsg_kref_release_function); 957 mutex_unlock(&bsg_mutex); 958 } 959 EXPORT_SYMBOL_GPL(bsg_unregister_queue); 960 961 int bsg_register_queue(struct request_queue *q, struct device *parent, 962 const char *name, void (*release)(struct device *)) 963 { 964 struct bsg_class_device *bcd; 965 dev_t dev; 966 int ret; 967 struct device *class_dev = NULL; 968 const char *devname; 969 970 if (name) 971 devname = name; 972 else 973 devname = dev_name(parent); 974 975 /* 976 * we need a proper transport to send commands, not a stacked device 977 */ 978 if (!queue_is_rq_based(q)) 979 return 0; 980 981 bcd = &q->bsg_dev; 982 memset(bcd, 0, sizeof(*bcd)); 983 984 mutex_lock(&bsg_mutex); 985 986 ret = idr_alloc(&bsg_minor_idr, bcd, 0, BSG_MAX_DEVS, GFP_KERNEL); 987 if (ret < 0) { 988 if (ret == -ENOSPC) { 989 printk(KERN_ERR "bsg: too many bsg devices\n"); 990 ret = -EINVAL; 991 } 992 goto unlock; 993 } 994 995 bcd->minor = ret; 996 bcd->queue = q; 997 bcd->parent = get_device(parent); 998 bcd->release = release; 999 kref_init(&bcd->ref); 1000 dev = MKDEV(bsg_major, bcd->minor); 1001 class_dev = device_create(bsg_class, parent, dev, NULL, "%s", devname); 1002 if (IS_ERR(class_dev)) { 1003 ret = PTR_ERR(class_dev); 1004 goto put_dev; 1005 } 1006 bcd->class_dev = class_dev; 1007 1008 if (q->kobj.sd) { 1009 ret = sysfs_create_link(&q->kobj, &bcd->class_dev->kobj, "bsg"); 1010 if (ret) 1011 goto unregister_class_dev; 1012 } 1013 1014 mutex_unlock(&bsg_mutex); 1015 return 0; 1016 1017 unregister_class_dev: 1018 device_unregister(class_dev); 1019 put_dev: 1020 put_device(parent); 1021 idr_remove(&bsg_minor_idr, bcd->minor); 1022 unlock: 1023 mutex_unlock(&bsg_mutex); 1024 return ret; 1025 } 1026 EXPORT_SYMBOL_GPL(bsg_register_queue); 1027 1028 static struct cdev bsg_cdev; 1029 1030 static char *bsg_devnode(struct device *dev, umode_t *mode) 1031 { 1032 return kasprintf(GFP_KERNEL, "bsg/%s", dev_name(dev)); 1033 } 1034 1035 static int __init bsg_init(void) 1036 { 1037 int ret, i; 1038 dev_t devid; 1039 1040 bsg_cmd_cachep = kmem_cache_create("bsg_cmd", 1041 sizeof(struct bsg_command), 0, 0, NULL); 1042 if (!bsg_cmd_cachep) { 1043 printk(KERN_ERR "bsg: failed creating slab cache\n"); 1044 return -ENOMEM; 1045 } 1046 1047 for (i = 0; i < BSG_LIST_ARRAY_SIZE; i++) 1048 INIT_HLIST_HEAD(&bsg_device_list[i]); 1049 1050 bsg_class = class_create(THIS_MODULE, "bsg"); 1051 if (IS_ERR(bsg_class)) { 1052 ret = PTR_ERR(bsg_class); 1053 goto destroy_kmemcache; 1054 } 1055 bsg_class->devnode = bsg_devnode; 1056 1057 ret = alloc_chrdev_region(&devid, 0, BSG_MAX_DEVS, "bsg"); 1058 if (ret) 1059 goto destroy_bsg_class; 1060 1061 bsg_major = MAJOR(devid); 1062 1063 cdev_init(&bsg_cdev, &bsg_fops); 1064 ret = cdev_add(&bsg_cdev, MKDEV(bsg_major, 0), BSG_MAX_DEVS); 1065 if (ret) 1066 goto unregister_chrdev; 1067 1068 printk(KERN_INFO BSG_DESCRIPTION " version " BSG_VERSION 1069 " loaded (major %d)\n", bsg_major); 1070 return 0; 1071 unregister_chrdev: 1072 unregister_chrdev_region(MKDEV(bsg_major, 0), BSG_MAX_DEVS); 1073 destroy_bsg_class: 1074 class_destroy(bsg_class); 1075 destroy_kmemcache: 1076 kmem_cache_destroy(bsg_cmd_cachep); 1077 return ret; 1078 } 1079 1080 MODULE_AUTHOR("Jens Axboe"); 1081 MODULE_DESCRIPTION(BSG_DESCRIPTION); 1082 MODULE_LICENSE("GPL"); 1083 1084 device_initcall(bsg_init); 1085