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 #define uptr64(val) ((void __user *)(uintptr_t)(val)) 134 135 static int bsg_scsi_check_proto(struct sg_io_v4 *hdr) 136 { 137 if (hdr->protocol != BSG_PROTOCOL_SCSI || 138 hdr->subprotocol != BSG_SUB_PROTOCOL_SCSI_CMD) 139 return -EINVAL; 140 return 0; 141 } 142 143 static int bsg_scsi_fill_hdr(struct request *rq, struct sg_io_v4 *hdr, 144 fmode_t mode) 145 { 146 struct scsi_request *sreq = scsi_req(rq); 147 148 sreq->cmd_len = hdr->request_len; 149 if (sreq->cmd_len > BLK_MAX_CDB) { 150 sreq->cmd = kzalloc(sreq->cmd_len, GFP_KERNEL); 151 if (!sreq->cmd) 152 return -ENOMEM; 153 } 154 155 if (copy_from_user(sreq->cmd, uptr64(hdr->request), sreq->cmd_len)) 156 return -EFAULT; 157 if (blk_verify_command(sreq->cmd, mode)) 158 return -EPERM; 159 return 0; 160 } 161 162 static int bsg_scsi_complete_rq(struct request *rq, struct sg_io_v4 *hdr) 163 { 164 struct scsi_request *sreq = scsi_req(rq); 165 int ret = 0; 166 167 /* 168 * fill in all the output members 169 */ 170 hdr->device_status = sreq->result & 0xff; 171 hdr->transport_status = host_byte(sreq->result); 172 hdr->driver_status = driver_byte(sreq->result); 173 hdr->info = 0; 174 if (hdr->device_status || hdr->transport_status || hdr->driver_status) 175 hdr->info |= SG_INFO_CHECK; 176 hdr->response_len = 0; 177 178 if (sreq->sense_len && hdr->response) { 179 int len = min_t(unsigned int, hdr->max_response_len, 180 sreq->sense_len); 181 182 if (copy_to_user(uptr64(hdr->response), sreq->sense, len)) 183 ret = -EFAULT; 184 else 185 hdr->response_len = len; 186 } 187 188 if (rq->next_rq) { 189 hdr->dout_resid = sreq->resid_len; 190 hdr->din_resid = scsi_req(rq->next_rq)->resid_len; 191 } else if (rq_data_dir(rq) == READ) { 192 hdr->din_resid = sreq->resid_len; 193 } else { 194 hdr->dout_resid = sreq->resid_len; 195 } 196 197 return ret; 198 } 199 200 static void bsg_scsi_free_rq(struct request *rq) 201 { 202 scsi_req_free_cmd(scsi_req(rq)); 203 } 204 205 static const struct bsg_ops bsg_scsi_ops = { 206 .check_proto = bsg_scsi_check_proto, 207 .fill_hdr = bsg_scsi_fill_hdr, 208 .complete_rq = bsg_scsi_complete_rq, 209 .free_rq = bsg_scsi_free_rq, 210 }; 211 212 static struct request * 213 bsg_map_hdr(struct request_queue *q, struct sg_io_v4 *hdr, fmode_t mode) 214 { 215 struct request *rq, *next_rq = NULL; 216 int ret; 217 218 if (!q->bsg_dev.class_dev) 219 return ERR_PTR(-ENXIO); 220 221 if (hdr->guard != 'Q') 222 return ERR_PTR(-EINVAL); 223 224 ret = q->bsg_dev.ops->check_proto(hdr); 225 if (ret) 226 return ERR_PTR(ret); 227 228 rq = blk_get_request(q, hdr->dout_xfer_len ? 229 REQ_OP_SCSI_OUT : REQ_OP_SCSI_IN, 0); 230 if (IS_ERR(rq)) 231 return rq; 232 233 ret = q->bsg_dev.ops->fill_hdr(rq, hdr, mode); 234 if (ret) 235 goto out; 236 237 rq->timeout = msecs_to_jiffies(hdr->timeout); 238 if (!rq->timeout) 239 rq->timeout = q->sg_timeout; 240 if (!rq->timeout) 241 rq->timeout = BLK_DEFAULT_SG_TIMEOUT; 242 if (rq->timeout < BLK_MIN_SG_TIMEOUT) 243 rq->timeout = BLK_MIN_SG_TIMEOUT; 244 245 if (hdr->dout_xfer_len && hdr->din_xfer_len) { 246 if (!test_bit(QUEUE_FLAG_BIDI, &q->queue_flags)) { 247 ret = -EOPNOTSUPP; 248 goto out; 249 } 250 251 next_rq = blk_get_request(q, REQ_OP_SCSI_IN, 0); 252 if (IS_ERR(next_rq)) { 253 ret = PTR_ERR(next_rq); 254 goto out; 255 } 256 257 rq->next_rq = next_rq; 258 ret = blk_rq_map_user(q, next_rq, NULL, uptr64(hdr->din_xferp), 259 hdr->din_xfer_len, GFP_KERNEL); 260 if (ret) 261 goto out_free_nextrq; 262 } 263 264 if (hdr->dout_xfer_len) { 265 ret = blk_rq_map_user(q, rq, NULL, uptr64(hdr->dout_xferp), 266 hdr->dout_xfer_len, GFP_KERNEL); 267 } else if (hdr->din_xfer_len) { 268 ret = blk_rq_map_user(q, rq, NULL, uptr64(hdr->din_xferp), 269 hdr->din_xfer_len, GFP_KERNEL); 270 } 271 272 if (ret) 273 goto out_unmap_nextrq; 274 return rq; 275 276 out_unmap_nextrq: 277 if (rq->next_rq) 278 blk_rq_unmap_user(rq->next_rq->bio); 279 out_free_nextrq: 280 if (rq->next_rq) 281 blk_put_request(rq->next_rq); 282 out: 283 q->bsg_dev.ops->free_rq(rq); 284 blk_put_request(rq); 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 int ret; 387 388 ret = rq->q->bsg_dev.ops->complete_rq(rq, hdr); 389 390 if (rq->next_rq) { 391 blk_rq_unmap_user(bidi_bio); 392 blk_put_request(rq->next_rq); 393 } 394 395 blk_rq_unmap_user(bio); 396 rq->q->bsg_dev.ops->free_rq(rq); 397 blk_put_request(rq); 398 return ret; 399 } 400 401 static bool bsg_complete(struct bsg_device *bd) 402 { 403 bool ret = false; 404 bool spin; 405 406 do { 407 spin_lock_irq(&bd->lock); 408 409 BUG_ON(bd->done_cmds > bd->queued_cmds); 410 411 /* 412 * All commands consumed. 413 */ 414 if (bd->done_cmds == bd->queued_cmds) 415 ret = true; 416 417 spin = !test_bit(BSG_F_BLOCK, &bd->flags); 418 419 spin_unlock_irq(&bd->lock); 420 } while (!ret && spin); 421 422 return ret; 423 } 424 425 static int bsg_complete_all_commands(struct bsg_device *bd) 426 { 427 struct bsg_command *bc; 428 int ret, tret; 429 430 bsg_dbg(bd, "entered\n"); 431 432 /* 433 * wait for all commands to complete 434 */ 435 io_wait_event(bd->wq_done, bsg_complete(bd)); 436 437 /* 438 * discard done commands 439 */ 440 ret = 0; 441 do { 442 spin_lock_irq(&bd->lock); 443 if (!bd->queued_cmds) { 444 spin_unlock_irq(&bd->lock); 445 break; 446 } 447 spin_unlock_irq(&bd->lock); 448 449 bc = bsg_get_done_cmd(bd); 450 if (IS_ERR(bc)) 451 break; 452 453 tret = blk_complete_sgv4_hdr_rq(bc->rq, &bc->hdr, bc->bio, 454 bc->bidi_bio); 455 if (!ret) 456 ret = tret; 457 458 bsg_free_command(bc); 459 } while (1); 460 461 return ret; 462 } 463 464 static int 465 __bsg_read(char __user *buf, size_t count, struct bsg_device *bd, 466 const struct iovec *iov, ssize_t *bytes_read) 467 { 468 struct bsg_command *bc; 469 int nr_commands, ret; 470 471 if (count % sizeof(struct sg_io_v4)) 472 return -EINVAL; 473 474 ret = 0; 475 nr_commands = count / sizeof(struct sg_io_v4); 476 while (nr_commands) { 477 bc = bsg_get_done_cmd(bd); 478 if (IS_ERR(bc)) { 479 ret = PTR_ERR(bc); 480 break; 481 } 482 483 /* 484 * this is the only case where we need to copy data back 485 * after completing the request. so do that here, 486 * bsg_complete_work() cannot do that for us 487 */ 488 ret = blk_complete_sgv4_hdr_rq(bc->rq, &bc->hdr, bc->bio, 489 bc->bidi_bio); 490 491 if (copy_to_user(buf, &bc->hdr, sizeof(bc->hdr))) 492 ret = -EFAULT; 493 494 bsg_free_command(bc); 495 496 if (ret) 497 break; 498 499 buf += sizeof(struct sg_io_v4); 500 *bytes_read += sizeof(struct sg_io_v4); 501 nr_commands--; 502 } 503 504 return ret; 505 } 506 507 static inline void bsg_set_block(struct bsg_device *bd, struct file *file) 508 { 509 if (file->f_flags & O_NONBLOCK) 510 clear_bit(BSG_F_BLOCK, &bd->flags); 511 else 512 set_bit(BSG_F_BLOCK, &bd->flags); 513 } 514 515 /* 516 * Check if the error is a "real" error that we should return. 517 */ 518 static inline int err_block_err(int ret) 519 { 520 if (ret && ret != -ENOSPC && ret != -ENODATA && ret != -EAGAIN) 521 return 1; 522 523 return 0; 524 } 525 526 static ssize_t 527 bsg_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) 528 { 529 struct bsg_device *bd = file->private_data; 530 int ret; 531 ssize_t bytes_read; 532 533 bsg_dbg(bd, "read %zd bytes\n", count); 534 535 bsg_set_block(bd, file); 536 537 bytes_read = 0; 538 ret = __bsg_read(buf, count, bd, NULL, &bytes_read); 539 *ppos = bytes_read; 540 541 if (!bytes_read || err_block_err(ret)) 542 bytes_read = ret; 543 544 return bytes_read; 545 } 546 547 static int __bsg_write(struct bsg_device *bd, const char __user *buf, 548 size_t count, ssize_t *bytes_written, fmode_t mode) 549 { 550 struct bsg_command *bc; 551 struct request *rq; 552 int ret, nr_commands; 553 554 if (count % sizeof(struct sg_io_v4)) 555 return -EINVAL; 556 557 nr_commands = count / sizeof(struct sg_io_v4); 558 rq = NULL; 559 bc = NULL; 560 ret = 0; 561 while (nr_commands) { 562 struct request_queue *q = bd->queue; 563 564 bc = bsg_alloc_command(bd); 565 if (IS_ERR(bc)) { 566 ret = PTR_ERR(bc); 567 bc = NULL; 568 break; 569 } 570 571 if (copy_from_user(&bc->hdr, buf, sizeof(bc->hdr))) { 572 ret = -EFAULT; 573 break; 574 } 575 576 /* 577 * get a request, fill in the blanks, and add to request queue 578 */ 579 rq = bsg_map_hdr(bd->queue, &bc->hdr, mode); 580 if (IS_ERR(rq)) { 581 ret = PTR_ERR(rq); 582 rq = NULL; 583 break; 584 } 585 586 bsg_add_command(bd, q, bc, rq); 587 bc = NULL; 588 rq = NULL; 589 nr_commands--; 590 buf += sizeof(struct sg_io_v4); 591 *bytes_written += sizeof(struct sg_io_v4); 592 } 593 594 if (bc) 595 bsg_free_command(bc); 596 597 return ret; 598 } 599 600 static ssize_t 601 bsg_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) 602 { 603 struct bsg_device *bd = file->private_data; 604 ssize_t bytes_written; 605 int ret; 606 607 bsg_dbg(bd, "write %zd bytes\n", count); 608 609 if (unlikely(uaccess_kernel())) 610 return -EINVAL; 611 612 bsg_set_block(bd, file); 613 614 bytes_written = 0; 615 ret = __bsg_write(bd, buf, count, &bytes_written, file->f_mode); 616 617 *ppos = bytes_written; 618 619 /* 620 * return bytes written on non-fatal errors 621 */ 622 if (!bytes_written || err_block_err(ret)) 623 bytes_written = ret; 624 625 bsg_dbg(bd, "returning %zd\n", bytes_written); 626 return bytes_written; 627 } 628 629 static struct bsg_device *bsg_alloc_device(void) 630 { 631 struct bsg_device *bd; 632 633 bd = kzalloc(sizeof(struct bsg_device), GFP_KERNEL); 634 if (unlikely(!bd)) 635 return NULL; 636 637 spin_lock_init(&bd->lock); 638 639 bd->max_queue = BSG_DEFAULT_CMDS; 640 641 INIT_LIST_HEAD(&bd->busy_list); 642 INIT_LIST_HEAD(&bd->done_list); 643 INIT_HLIST_NODE(&bd->dev_list); 644 645 init_waitqueue_head(&bd->wq_free); 646 init_waitqueue_head(&bd->wq_done); 647 return bd; 648 } 649 650 static int bsg_put_device(struct bsg_device *bd) 651 { 652 int ret = 0, do_free; 653 struct request_queue *q = bd->queue; 654 655 mutex_lock(&bsg_mutex); 656 657 do_free = atomic_dec_and_test(&bd->ref_count); 658 if (!do_free) { 659 mutex_unlock(&bsg_mutex); 660 goto out; 661 } 662 663 hlist_del(&bd->dev_list); 664 mutex_unlock(&bsg_mutex); 665 666 bsg_dbg(bd, "tearing down\n"); 667 668 /* 669 * close can always block 670 */ 671 set_bit(BSG_F_BLOCK, &bd->flags); 672 673 /* 674 * correct error detection baddies here again. it's the responsibility 675 * of the app to properly reap commands before close() if it wants 676 * fool-proof error detection 677 */ 678 ret = bsg_complete_all_commands(bd); 679 680 kfree(bd); 681 out: 682 if (do_free) 683 blk_put_queue(q); 684 return ret; 685 } 686 687 static struct bsg_device *bsg_add_device(struct inode *inode, 688 struct request_queue *rq, 689 struct file *file) 690 { 691 struct bsg_device *bd; 692 unsigned char buf[32]; 693 694 lockdep_assert_held(&bsg_mutex); 695 696 if (!blk_get_queue(rq)) 697 return ERR_PTR(-ENXIO); 698 699 bd = bsg_alloc_device(); 700 if (!bd) { 701 blk_put_queue(rq); 702 return ERR_PTR(-ENOMEM); 703 } 704 705 bd->queue = rq; 706 707 bsg_set_block(bd, file); 708 709 atomic_set(&bd->ref_count, 1); 710 hlist_add_head(&bd->dev_list, bsg_dev_idx_hash(iminor(inode))); 711 712 strncpy(bd->name, dev_name(rq->bsg_dev.class_dev), sizeof(bd->name) - 1); 713 bsg_dbg(bd, "bound to <%s>, max queue %d\n", 714 format_dev_t(buf, inode->i_rdev), bd->max_queue); 715 716 return bd; 717 } 718 719 static struct bsg_device *__bsg_get_device(int minor, struct request_queue *q) 720 { 721 struct bsg_device *bd; 722 723 lockdep_assert_held(&bsg_mutex); 724 725 hlist_for_each_entry(bd, bsg_dev_idx_hash(minor), dev_list) { 726 if (bd->queue == q) { 727 atomic_inc(&bd->ref_count); 728 goto found; 729 } 730 } 731 bd = NULL; 732 found: 733 return bd; 734 } 735 736 static struct bsg_device *bsg_get_device(struct inode *inode, struct file *file) 737 { 738 struct bsg_device *bd; 739 struct bsg_class_device *bcd; 740 741 /* 742 * find the class device 743 */ 744 mutex_lock(&bsg_mutex); 745 bcd = idr_find(&bsg_minor_idr, iminor(inode)); 746 747 if (!bcd) { 748 bd = ERR_PTR(-ENODEV); 749 goto out_unlock; 750 } 751 752 bd = __bsg_get_device(iminor(inode), bcd->queue); 753 if (!bd) 754 bd = bsg_add_device(inode, bcd->queue, file); 755 756 out_unlock: 757 mutex_unlock(&bsg_mutex); 758 return bd; 759 } 760 761 static int bsg_open(struct inode *inode, struct file *file) 762 { 763 struct bsg_device *bd; 764 765 bd = bsg_get_device(inode, file); 766 767 if (IS_ERR(bd)) 768 return PTR_ERR(bd); 769 770 file->private_data = bd; 771 return 0; 772 } 773 774 static int bsg_release(struct inode *inode, struct file *file) 775 { 776 struct bsg_device *bd = file->private_data; 777 778 file->private_data = NULL; 779 return bsg_put_device(bd); 780 } 781 782 static __poll_t bsg_poll(struct file *file, poll_table *wait) 783 { 784 struct bsg_device *bd = file->private_data; 785 __poll_t mask = 0; 786 787 poll_wait(file, &bd->wq_done, wait); 788 poll_wait(file, &bd->wq_free, wait); 789 790 spin_lock_irq(&bd->lock); 791 if (!list_empty(&bd->done_list)) 792 mask |= EPOLLIN | EPOLLRDNORM; 793 if (bd->queued_cmds < bd->max_queue) 794 mask |= EPOLLOUT; 795 spin_unlock_irq(&bd->lock); 796 797 return mask; 798 } 799 800 static long bsg_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 801 { 802 struct bsg_device *bd = file->private_data; 803 int __user *uarg = (int __user *) arg; 804 int ret; 805 806 switch (cmd) { 807 /* 808 * our own ioctls 809 */ 810 case SG_GET_COMMAND_Q: 811 return put_user(bd->max_queue, uarg); 812 case SG_SET_COMMAND_Q: { 813 int queue; 814 815 if (get_user(queue, uarg)) 816 return -EFAULT; 817 if (queue < 1) 818 return -EINVAL; 819 820 spin_lock_irq(&bd->lock); 821 bd->max_queue = queue; 822 spin_unlock_irq(&bd->lock); 823 return 0; 824 } 825 826 /* 827 * SCSI/sg ioctls 828 */ 829 case SG_GET_VERSION_NUM: 830 case SCSI_IOCTL_GET_IDLUN: 831 case SCSI_IOCTL_GET_BUS_NUMBER: 832 case SG_SET_TIMEOUT: 833 case SG_GET_TIMEOUT: 834 case SG_GET_RESERVED_SIZE: 835 case SG_SET_RESERVED_SIZE: 836 case SG_EMULATED_HOST: 837 case SCSI_IOCTL_SEND_COMMAND: { 838 void __user *uarg = (void __user *) arg; 839 return scsi_cmd_ioctl(bd->queue, NULL, file->f_mode, cmd, uarg); 840 } 841 case SG_IO: { 842 struct request *rq; 843 struct bio *bio, *bidi_bio = NULL; 844 struct sg_io_v4 hdr; 845 int at_head; 846 847 if (copy_from_user(&hdr, uarg, sizeof(hdr))) 848 return -EFAULT; 849 850 rq = bsg_map_hdr(bd->queue, &hdr, file->f_mode); 851 if (IS_ERR(rq)) 852 return PTR_ERR(rq); 853 854 bio = rq->bio; 855 if (rq->next_rq) 856 bidi_bio = rq->next_rq->bio; 857 858 at_head = (0 == (hdr.flags & BSG_FLAG_Q_AT_TAIL)); 859 blk_execute_rq(bd->queue, NULL, rq, at_head); 860 ret = blk_complete_sgv4_hdr_rq(rq, &hdr, bio, bidi_bio); 861 862 if (copy_to_user(uarg, &hdr, sizeof(hdr))) 863 return -EFAULT; 864 865 return ret; 866 } 867 default: 868 return -ENOTTY; 869 } 870 } 871 872 static const struct file_operations bsg_fops = { 873 .read = bsg_read, 874 .write = bsg_write, 875 .poll = bsg_poll, 876 .open = bsg_open, 877 .release = bsg_release, 878 .unlocked_ioctl = bsg_ioctl, 879 .owner = THIS_MODULE, 880 .llseek = default_llseek, 881 }; 882 883 void bsg_unregister_queue(struct request_queue *q) 884 { 885 struct bsg_class_device *bcd = &q->bsg_dev; 886 887 if (!bcd->class_dev) 888 return; 889 890 mutex_lock(&bsg_mutex); 891 idr_remove(&bsg_minor_idr, bcd->minor); 892 if (q->kobj.sd) 893 sysfs_remove_link(&q->kobj, "bsg"); 894 device_unregister(bcd->class_dev); 895 bcd->class_dev = NULL; 896 mutex_unlock(&bsg_mutex); 897 } 898 EXPORT_SYMBOL_GPL(bsg_unregister_queue); 899 900 int bsg_register_queue(struct request_queue *q, struct device *parent, 901 const char *name, const struct bsg_ops *ops) 902 { 903 struct bsg_class_device *bcd; 904 dev_t dev; 905 int ret; 906 struct device *class_dev = NULL; 907 908 /* 909 * we need a proper transport to send commands, not a stacked device 910 */ 911 if (!queue_is_rq_based(q)) 912 return 0; 913 914 bcd = &q->bsg_dev; 915 memset(bcd, 0, sizeof(*bcd)); 916 917 mutex_lock(&bsg_mutex); 918 919 ret = idr_alloc(&bsg_minor_idr, bcd, 0, BSG_MAX_DEVS, GFP_KERNEL); 920 if (ret < 0) { 921 if (ret == -ENOSPC) { 922 printk(KERN_ERR "bsg: too many bsg devices\n"); 923 ret = -EINVAL; 924 } 925 goto unlock; 926 } 927 928 bcd->minor = ret; 929 bcd->queue = q; 930 bcd->ops = ops; 931 dev = MKDEV(bsg_major, bcd->minor); 932 class_dev = device_create(bsg_class, parent, dev, NULL, "%s", name); 933 if (IS_ERR(class_dev)) { 934 ret = PTR_ERR(class_dev); 935 goto idr_remove; 936 } 937 bcd->class_dev = class_dev; 938 939 if (q->kobj.sd) { 940 ret = sysfs_create_link(&q->kobj, &bcd->class_dev->kobj, "bsg"); 941 if (ret) 942 goto unregister_class_dev; 943 } 944 945 mutex_unlock(&bsg_mutex); 946 return 0; 947 948 unregister_class_dev: 949 device_unregister(class_dev); 950 idr_remove: 951 idr_remove(&bsg_minor_idr, bcd->minor); 952 unlock: 953 mutex_unlock(&bsg_mutex); 954 return ret; 955 } 956 957 int bsg_scsi_register_queue(struct request_queue *q, struct device *parent) 958 { 959 if (!blk_queue_scsi_passthrough(q)) { 960 WARN_ONCE(true, "Attempt to register a non-SCSI queue\n"); 961 return -EINVAL; 962 } 963 964 return bsg_register_queue(q, parent, dev_name(parent), &bsg_scsi_ops); 965 } 966 EXPORT_SYMBOL_GPL(bsg_scsi_register_queue); 967 968 static struct cdev bsg_cdev; 969 970 static char *bsg_devnode(struct device *dev, umode_t *mode) 971 { 972 return kasprintf(GFP_KERNEL, "bsg/%s", dev_name(dev)); 973 } 974 975 static int __init bsg_init(void) 976 { 977 int ret, i; 978 dev_t devid; 979 980 bsg_cmd_cachep = kmem_cache_create("bsg_cmd", 981 sizeof(struct bsg_command), 0, 0, NULL); 982 if (!bsg_cmd_cachep) { 983 printk(KERN_ERR "bsg: failed creating slab cache\n"); 984 return -ENOMEM; 985 } 986 987 for (i = 0; i < BSG_LIST_ARRAY_SIZE; i++) 988 INIT_HLIST_HEAD(&bsg_device_list[i]); 989 990 bsg_class = class_create(THIS_MODULE, "bsg"); 991 if (IS_ERR(bsg_class)) { 992 ret = PTR_ERR(bsg_class); 993 goto destroy_kmemcache; 994 } 995 bsg_class->devnode = bsg_devnode; 996 997 ret = alloc_chrdev_region(&devid, 0, BSG_MAX_DEVS, "bsg"); 998 if (ret) 999 goto destroy_bsg_class; 1000 1001 bsg_major = MAJOR(devid); 1002 1003 cdev_init(&bsg_cdev, &bsg_fops); 1004 ret = cdev_add(&bsg_cdev, MKDEV(bsg_major, 0), BSG_MAX_DEVS); 1005 if (ret) 1006 goto unregister_chrdev; 1007 1008 printk(KERN_INFO BSG_DESCRIPTION " version " BSG_VERSION 1009 " loaded (major %d)\n", bsg_major); 1010 return 0; 1011 unregister_chrdev: 1012 unregister_chrdev_region(MKDEV(bsg_major, 0), BSG_MAX_DEVS); 1013 destroy_bsg_class: 1014 class_destroy(bsg_class); 1015 destroy_kmemcache: 1016 kmem_cache_destroy(bsg_cmd_cachep); 1017 return ret; 1018 } 1019 1020 MODULE_AUTHOR("Jens Axboe"); 1021 MODULE_DESCRIPTION(BSG_DESCRIPTION); 1022 MODULE_LICENSE("GPL"); 1023 1024 device_initcall(bsg_init); 1025