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 } else { 271 ret = blk_rq_map_user(q, rq, NULL, NULL, 0, GFP_KERNEL); 272 } 273 274 if (ret) 275 goto out_unmap_nextrq; 276 return rq; 277 278 out_unmap_nextrq: 279 if (rq->next_rq) 280 blk_rq_unmap_user(rq->next_rq->bio); 281 out_free_nextrq: 282 if (rq->next_rq) 283 blk_put_request(rq->next_rq); 284 out: 285 q->bsg_dev.ops->free_rq(rq); 286 blk_put_request(rq); 287 return ERR_PTR(ret); 288 } 289 290 /* 291 * async completion call-back from the block layer, when scsi/ide/whatever 292 * calls end_that_request_last() on a request 293 */ 294 static void bsg_rq_end_io(struct request *rq, blk_status_t status) 295 { 296 struct bsg_command *bc = rq->end_io_data; 297 struct bsg_device *bd = bc->bd; 298 unsigned long flags; 299 300 bsg_dbg(bd, "finished rq %p bc %p, bio %p\n", 301 rq, bc, bc->bio); 302 303 bc->hdr.duration = jiffies_to_msecs(jiffies - bc->hdr.duration); 304 305 spin_lock_irqsave(&bd->lock, flags); 306 list_move_tail(&bc->list, &bd->done_list); 307 bd->done_cmds++; 308 spin_unlock_irqrestore(&bd->lock, flags); 309 310 wake_up(&bd->wq_done); 311 } 312 313 /* 314 * do final setup of a 'bc' and submit the matching 'rq' to the block 315 * layer for io 316 */ 317 static void bsg_add_command(struct bsg_device *bd, struct request_queue *q, 318 struct bsg_command *bc, struct request *rq) 319 { 320 int at_head = (0 == (bc->hdr.flags & BSG_FLAG_Q_AT_TAIL)); 321 322 /* 323 * add bc command to busy queue and submit rq for io 324 */ 325 bc->rq = rq; 326 bc->bio = rq->bio; 327 if (rq->next_rq) 328 bc->bidi_bio = rq->next_rq->bio; 329 bc->hdr.duration = jiffies; 330 spin_lock_irq(&bd->lock); 331 list_add_tail(&bc->list, &bd->busy_list); 332 spin_unlock_irq(&bd->lock); 333 334 bsg_dbg(bd, "queueing rq %p, bc %p\n", rq, bc); 335 336 rq->end_io_data = bc; 337 blk_execute_rq_nowait(q, NULL, rq, at_head, bsg_rq_end_io); 338 } 339 340 static struct bsg_command *bsg_next_done_cmd(struct bsg_device *bd) 341 { 342 struct bsg_command *bc = NULL; 343 344 spin_lock_irq(&bd->lock); 345 if (bd->done_cmds) { 346 bc = list_first_entry(&bd->done_list, struct bsg_command, list); 347 list_del(&bc->list); 348 bd->done_cmds--; 349 } 350 spin_unlock_irq(&bd->lock); 351 352 return bc; 353 } 354 355 /* 356 * Get a finished command from the done list 357 */ 358 static struct bsg_command *bsg_get_done_cmd(struct bsg_device *bd) 359 { 360 struct bsg_command *bc; 361 int ret; 362 363 do { 364 bc = bsg_next_done_cmd(bd); 365 if (bc) 366 break; 367 368 if (!test_bit(BSG_F_BLOCK, &bd->flags)) { 369 bc = ERR_PTR(-EAGAIN); 370 break; 371 } 372 373 ret = wait_event_interruptible(bd->wq_done, bd->done_cmds); 374 if (ret) { 375 bc = ERR_PTR(-ERESTARTSYS); 376 break; 377 } 378 } while (1); 379 380 bsg_dbg(bd, "returning done %p\n", bc); 381 382 return bc; 383 } 384 385 static int blk_complete_sgv4_hdr_rq(struct request *rq, struct sg_io_v4 *hdr, 386 struct bio *bio, struct bio *bidi_bio) 387 { 388 int ret; 389 390 ret = rq->q->bsg_dev.ops->complete_rq(rq, hdr); 391 392 if (rq->next_rq) { 393 blk_rq_unmap_user(bidi_bio); 394 blk_put_request(rq->next_rq); 395 } 396 397 blk_rq_unmap_user(bio); 398 rq->q->bsg_dev.ops->free_rq(rq); 399 blk_put_request(rq); 400 return ret; 401 } 402 403 static bool bsg_complete(struct bsg_device *bd) 404 { 405 bool ret = false; 406 bool spin; 407 408 do { 409 spin_lock_irq(&bd->lock); 410 411 BUG_ON(bd->done_cmds > bd->queued_cmds); 412 413 /* 414 * All commands consumed. 415 */ 416 if (bd->done_cmds == bd->queued_cmds) 417 ret = true; 418 419 spin = !test_bit(BSG_F_BLOCK, &bd->flags); 420 421 spin_unlock_irq(&bd->lock); 422 } while (!ret && spin); 423 424 return ret; 425 } 426 427 static int bsg_complete_all_commands(struct bsg_device *bd) 428 { 429 struct bsg_command *bc; 430 int ret, tret; 431 432 bsg_dbg(bd, "entered\n"); 433 434 /* 435 * wait for all commands to complete 436 */ 437 io_wait_event(bd->wq_done, bsg_complete(bd)); 438 439 /* 440 * discard done commands 441 */ 442 ret = 0; 443 do { 444 spin_lock_irq(&bd->lock); 445 if (!bd->queued_cmds) { 446 spin_unlock_irq(&bd->lock); 447 break; 448 } 449 spin_unlock_irq(&bd->lock); 450 451 bc = bsg_get_done_cmd(bd); 452 if (IS_ERR(bc)) 453 break; 454 455 tret = blk_complete_sgv4_hdr_rq(bc->rq, &bc->hdr, bc->bio, 456 bc->bidi_bio); 457 if (!ret) 458 ret = tret; 459 460 bsg_free_command(bc); 461 } while (1); 462 463 return ret; 464 } 465 466 static int 467 __bsg_read(char __user *buf, size_t count, struct bsg_device *bd, 468 const struct iovec *iov, ssize_t *bytes_read) 469 { 470 struct bsg_command *bc; 471 int nr_commands, ret; 472 473 if (count % sizeof(struct sg_io_v4)) 474 return -EINVAL; 475 476 ret = 0; 477 nr_commands = count / sizeof(struct sg_io_v4); 478 while (nr_commands) { 479 bc = bsg_get_done_cmd(bd); 480 if (IS_ERR(bc)) { 481 ret = PTR_ERR(bc); 482 break; 483 } 484 485 /* 486 * this is the only case where we need to copy data back 487 * after completing the request. so do that here, 488 * bsg_complete_work() cannot do that for us 489 */ 490 ret = blk_complete_sgv4_hdr_rq(bc->rq, &bc->hdr, bc->bio, 491 bc->bidi_bio); 492 493 if (copy_to_user(buf, &bc->hdr, sizeof(bc->hdr))) 494 ret = -EFAULT; 495 496 bsg_free_command(bc); 497 498 if (ret) 499 break; 500 501 buf += sizeof(struct sg_io_v4); 502 *bytes_read += sizeof(struct sg_io_v4); 503 nr_commands--; 504 } 505 506 return ret; 507 } 508 509 static inline void bsg_set_block(struct bsg_device *bd, struct file *file) 510 { 511 if (file->f_flags & O_NONBLOCK) 512 clear_bit(BSG_F_BLOCK, &bd->flags); 513 else 514 set_bit(BSG_F_BLOCK, &bd->flags); 515 } 516 517 /* 518 * Check if the error is a "real" error that we should return. 519 */ 520 static inline int err_block_err(int ret) 521 { 522 if (ret && ret != -ENOSPC && ret != -ENODATA && ret != -EAGAIN) 523 return 1; 524 525 return 0; 526 } 527 528 static ssize_t 529 bsg_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) 530 { 531 struct bsg_device *bd = file->private_data; 532 int ret; 533 ssize_t bytes_read; 534 535 bsg_dbg(bd, "read %zd bytes\n", count); 536 537 bsg_set_block(bd, file); 538 539 bytes_read = 0; 540 ret = __bsg_read(buf, count, bd, NULL, &bytes_read); 541 *ppos = bytes_read; 542 543 if (!bytes_read || err_block_err(ret)) 544 bytes_read = ret; 545 546 return bytes_read; 547 } 548 549 static int __bsg_write(struct bsg_device *bd, const char __user *buf, 550 size_t count, ssize_t *bytes_written, fmode_t mode) 551 { 552 struct bsg_command *bc; 553 struct request *rq; 554 int ret, nr_commands; 555 556 if (count % sizeof(struct sg_io_v4)) 557 return -EINVAL; 558 559 nr_commands = count / sizeof(struct sg_io_v4); 560 rq = NULL; 561 bc = NULL; 562 ret = 0; 563 while (nr_commands) { 564 struct request_queue *q = bd->queue; 565 566 bc = bsg_alloc_command(bd); 567 if (IS_ERR(bc)) { 568 ret = PTR_ERR(bc); 569 bc = NULL; 570 break; 571 } 572 573 if (copy_from_user(&bc->hdr, buf, sizeof(bc->hdr))) { 574 ret = -EFAULT; 575 break; 576 } 577 578 /* 579 * get a request, fill in the blanks, and add to request queue 580 */ 581 rq = bsg_map_hdr(bd->queue, &bc->hdr, mode); 582 if (IS_ERR(rq)) { 583 ret = PTR_ERR(rq); 584 rq = NULL; 585 break; 586 } 587 588 bsg_add_command(bd, q, bc, rq); 589 bc = NULL; 590 rq = NULL; 591 nr_commands--; 592 buf += sizeof(struct sg_io_v4); 593 *bytes_written += sizeof(struct sg_io_v4); 594 } 595 596 if (bc) 597 bsg_free_command(bc); 598 599 return ret; 600 } 601 602 static ssize_t 603 bsg_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) 604 { 605 struct bsg_device *bd = file->private_data; 606 ssize_t bytes_written; 607 int ret; 608 609 bsg_dbg(bd, "write %zd bytes\n", count); 610 611 if (unlikely(uaccess_kernel())) 612 return -EINVAL; 613 614 bsg_set_block(bd, file); 615 616 bytes_written = 0; 617 ret = __bsg_write(bd, buf, count, &bytes_written, file->f_mode); 618 619 *ppos = bytes_written; 620 621 /* 622 * return bytes written on non-fatal errors 623 */ 624 if (!bytes_written || err_block_err(ret)) 625 bytes_written = ret; 626 627 bsg_dbg(bd, "returning %zd\n", bytes_written); 628 return bytes_written; 629 } 630 631 static struct bsg_device *bsg_alloc_device(void) 632 { 633 struct bsg_device *bd; 634 635 bd = kzalloc(sizeof(struct bsg_device), GFP_KERNEL); 636 if (unlikely(!bd)) 637 return NULL; 638 639 spin_lock_init(&bd->lock); 640 641 bd->max_queue = BSG_DEFAULT_CMDS; 642 643 INIT_LIST_HEAD(&bd->busy_list); 644 INIT_LIST_HEAD(&bd->done_list); 645 INIT_HLIST_NODE(&bd->dev_list); 646 647 init_waitqueue_head(&bd->wq_free); 648 init_waitqueue_head(&bd->wq_done); 649 return bd; 650 } 651 652 static int bsg_put_device(struct bsg_device *bd) 653 { 654 int ret = 0, do_free; 655 struct request_queue *q = bd->queue; 656 657 mutex_lock(&bsg_mutex); 658 659 do_free = atomic_dec_and_test(&bd->ref_count); 660 if (!do_free) { 661 mutex_unlock(&bsg_mutex); 662 goto out; 663 } 664 665 hlist_del(&bd->dev_list); 666 mutex_unlock(&bsg_mutex); 667 668 bsg_dbg(bd, "tearing down\n"); 669 670 /* 671 * close can always block 672 */ 673 set_bit(BSG_F_BLOCK, &bd->flags); 674 675 /* 676 * correct error detection baddies here again. it's the responsibility 677 * of the app to properly reap commands before close() if it wants 678 * fool-proof error detection 679 */ 680 ret = bsg_complete_all_commands(bd); 681 682 kfree(bd); 683 out: 684 if (do_free) 685 blk_put_queue(q); 686 return ret; 687 } 688 689 static struct bsg_device *bsg_add_device(struct inode *inode, 690 struct request_queue *rq, 691 struct file *file) 692 { 693 struct bsg_device *bd; 694 unsigned char buf[32]; 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 mutex_lock(&bsg_mutex); 711 hlist_add_head(&bd->dev_list, bsg_dev_idx_hash(iminor(inode))); 712 713 strncpy(bd->name, dev_name(rq->bsg_dev.class_dev), sizeof(bd->name) - 1); 714 bsg_dbg(bd, "bound to <%s>, max queue %d\n", 715 format_dev_t(buf, inode->i_rdev), bd->max_queue); 716 717 mutex_unlock(&bsg_mutex); 718 return bd; 719 } 720 721 static struct bsg_device *__bsg_get_device(int minor, struct request_queue *q) 722 { 723 struct bsg_device *bd; 724 725 mutex_lock(&bsg_mutex); 726 727 hlist_for_each_entry(bd, bsg_dev_idx_hash(minor), dev_list) { 728 if (bd->queue == q) { 729 atomic_inc(&bd->ref_count); 730 goto found; 731 } 732 } 733 bd = NULL; 734 found: 735 mutex_unlock(&bsg_mutex); 736 return bd; 737 } 738 739 static struct bsg_device *bsg_get_device(struct inode *inode, struct file *file) 740 { 741 struct bsg_device *bd; 742 struct bsg_class_device *bcd; 743 744 /* 745 * find the class device 746 */ 747 mutex_lock(&bsg_mutex); 748 bcd = idr_find(&bsg_minor_idr, iminor(inode)); 749 mutex_unlock(&bsg_mutex); 750 751 if (!bcd) 752 return ERR_PTR(-ENODEV); 753 754 bd = __bsg_get_device(iminor(inode), bcd->queue); 755 if (bd) 756 return bd; 757 758 bd = bsg_add_device(inode, bcd->queue, file); 759 760 return bd; 761 } 762 763 static int bsg_open(struct inode *inode, struct file *file) 764 { 765 struct bsg_device *bd; 766 767 bd = bsg_get_device(inode, file); 768 769 if (IS_ERR(bd)) 770 return PTR_ERR(bd); 771 772 file->private_data = bd; 773 return 0; 774 } 775 776 static int bsg_release(struct inode *inode, struct file *file) 777 { 778 struct bsg_device *bd = file->private_data; 779 780 file->private_data = NULL; 781 return bsg_put_device(bd); 782 } 783 784 static __poll_t bsg_poll(struct file *file, poll_table *wait) 785 { 786 struct bsg_device *bd = file->private_data; 787 __poll_t mask = 0; 788 789 poll_wait(file, &bd->wq_done, wait); 790 poll_wait(file, &bd->wq_free, wait); 791 792 spin_lock_irq(&bd->lock); 793 if (!list_empty(&bd->done_list)) 794 mask |= EPOLLIN | EPOLLRDNORM; 795 if (bd->queued_cmds < bd->max_queue) 796 mask |= EPOLLOUT; 797 spin_unlock_irq(&bd->lock); 798 799 return mask; 800 } 801 802 static long bsg_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 803 { 804 struct bsg_device *bd = file->private_data; 805 int __user *uarg = (int __user *) arg; 806 int ret; 807 808 switch (cmd) { 809 /* 810 * our own ioctls 811 */ 812 case SG_GET_COMMAND_Q: 813 return put_user(bd->max_queue, uarg); 814 case SG_SET_COMMAND_Q: { 815 int queue; 816 817 if (get_user(queue, uarg)) 818 return -EFAULT; 819 if (queue < 1) 820 return -EINVAL; 821 822 spin_lock_irq(&bd->lock); 823 bd->max_queue = queue; 824 spin_unlock_irq(&bd->lock); 825 return 0; 826 } 827 828 /* 829 * SCSI/sg ioctls 830 */ 831 case SG_GET_VERSION_NUM: 832 case SCSI_IOCTL_GET_IDLUN: 833 case SCSI_IOCTL_GET_BUS_NUMBER: 834 case SG_SET_TIMEOUT: 835 case SG_GET_TIMEOUT: 836 case SG_GET_RESERVED_SIZE: 837 case SG_SET_RESERVED_SIZE: 838 case SG_EMULATED_HOST: 839 case SCSI_IOCTL_SEND_COMMAND: { 840 void __user *uarg = (void __user *) arg; 841 return scsi_cmd_ioctl(bd->queue, NULL, file->f_mode, cmd, uarg); 842 } 843 case SG_IO: { 844 struct request *rq; 845 struct bio *bio, *bidi_bio = NULL; 846 struct sg_io_v4 hdr; 847 int at_head; 848 849 if (copy_from_user(&hdr, uarg, sizeof(hdr))) 850 return -EFAULT; 851 852 rq = bsg_map_hdr(bd->queue, &hdr, file->f_mode); 853 if (IS_ERR(rq)) 854 return PTR_ERR(rq); 855 856 bio = rq->bio; 857 if (rq->next_rq) 858 bidi_bio = rq->next_rq->bio; 859 860 at_head = (0 == (hdr.flags & BSG_FLAG_Q_AT_TAIL)); 861 blk_execute_rq(bd->queue, NULL, rq, at_head); 862 ret = blk_complete_sgv4_hdr_rq(rq, &hdr, bio, bidi_bio); 863 864 if (copy_to_user(uarg, &hdr, sizeof(hdr))) 865 return -EFAULT; 866 867 return ret; 868 } 869 default: 870 return -ENOTTY; 871 } 872 } 873 874 static const struct file_operations bsg_fops = { 875 .read = bsg_read, 876 .write = bsg_write, 877 .poll = bsg_poll, 878 .open = bsg_open, 879 .release = bsg_release, 880 .unlocked_ioctl = bsg_ioctl, 881 .owner = THIS_MODULE, 882 .llseek = default_llseek, 883 }; 884 885 void bsg_unregister_queue(struct request_queue *q) 886 { 887 struct bsg_class_device *bcd = &q->bsg_dev; 888 889 if (!bcd->class_dev) 890 return; 891 892 mutex_lock(&bsg_mutex); 893 idr_remove(&bsg_minor_idr, bcd->minor); 894 if (q->kobj.sd) 895 sysfs_remove_link(&q->kobj, "bsg"); 896 device_unregister(bcd->class_dev); 897 bcd->class_dev = NULL; 898 mutex_unlock(&bsg_mutex); 899 } 900 EXPORT_SYMBOL_GPL(bsg_unregister_queue); 901 902 int bsg_register_queue(struct request_queue *q, struct device *parent, 903 const char *name, const struct bsg_ops *ops) 904 { 905 struct bsg_class_device *bcd; 906 dev_t dev; 907 int ret; 908 struct device *class_dev = NULL; 909 910 /* 911 * we need a proper transport to send commands, not a stacked device 912 */ 913 if (!queue_is_rq_based(q)) 914 return 0; 915 916 bcd = &q->bsg_dev; 917 memset(bcd, 0, sizeof(*bcd)); 918 919 mutex_lock(&bsg_mutex); 920 921 ret = idr_alloc(&bsg_minor_idr, bcd, 0, BSG_MAX_DEVS, GFP_KERNEL); 922 if (ret < 0) { 923 if (ret == -ENOSPC) { 924 printk(KERN_ERR "bsg: too many bsg devices\n"); 925 ret = -EINVAL; 926 } 927 goto unlock; 928 } 929 930 bcd->minor = ret; 931 bcd->queue = q; 932 bcd->ops = ops; 933 dev = MKDEV(bsg_major, bcd->minor); 934 class_dev = device_create(bsg_class, parent, dev, NULL, "%s", name); 935 if (IS_ERR(class_dev)) { 936 ret = PTR_ERR(class_dev); 937 goto idr_remove; 938 } 939 bcd->class_dev = class_dev; 940 941 if (q->kobj.sd) { 942 ret = sysfs_create_link(&q->kobj, &bcd->class_dev->kobj, "bsg"); 943 if (ret) 944 goto unregister_class_dev; 945 } 946 947 mutex_unlock(&bsg_mutex); 948 return 0; 949 950 unregister_class_dev: 951 device_unregister(class_dev); 952 idr_remove: 953 idr_remove(&bsg_minor_idr, bcd->minor); 954 unlock: 955 mutex_unlock(&bsg_mutex); 956 return ret; 957 } 958 959 int bsg_scsi_register_queue(struct request_queue *q, struct device *parent) 960 { 961 if (!blk_queue_scsi_passthrough(q)) { 962 WARN_ONCE(true, "Attempt to register a non-SCSI queue\n"); 963 return -EINVAL; 964 } 965 966 return bsg_register_queue(q, parent, dev_name(parent), &bsg_scsi_ops); 967 } 968 EXPORT_SYMBOL_GPL(bsg_scsi_register_queue); 969 970 static struct cdev bsg_cdev; 971 972 static char *bsg_devnode(struct device *dev, umode_t *mode) 973 { 974 return kasprintf(GFP_KERNEL, "bsg/%s", dev_name(dev)); 975 } 976 977 static int __init bsg_init(void) 978 { 979 int ret, i; 980 dev_t devid; 981 982 bsg_cmd_cachep = kmem_cache_create("bsg_cmd", 983 sizeof(struct bsg_command), 0, 0, NULL); 984 if (!bsg_cmd_cachep) { 985 printk(KERN_ERR "bsg: failed creating slab cache\n"); 986 return -ENOMEM; 987 } 988 989 for (i = 0; i < BSG_LIST_ARRAY_SIZE; i++) 990 INIT_HLIST_HEAD(&bsg_device_list[i]); 991 992 bsg_class = class_create(THIS_MODULE, "bsg"); 993 if (IS_ERR(bsg_class)) { 994 ret = PTR_ERR(bsg_class); 995 goto destroy_kmemcache; 996 } 997 bsg_class->devnode = bsg_devnode; 998 999 ret = alloc_chrdev_region(&devid, 0, BSG_MAX_DEVS, "bsg"); 1000 if (ret) 1001 goto destroy_bsg_class; 1002 1003 bsg_major = MAJOR(devid); 1004 1005 cdev_init(&bsg_cdev, &bsg_fops); 1006 ret = cdev_add(&bsg_cdev, MKDEV(bsg_major, 0), BSG_MAX_DEVS); 1007 if (ret) 1008 goto unregister_chrdev; 1009 1010 printk(KERN_INFO BSG_DESCRIPTION " version " BSG_VERSION 1011 " loaded (major %d)\n", bsg_major); 1012 return 0; 1013 unregister_chrdev: 1014 unregister_chrdev_region(MKDEV(bsg_major, 0), BSG_MAX_DEVS); 1015 destroy_bsg_class: 1016 class_destroy(bsg_class); 1017 destroy_kmemcache: 1018 kmem_cache_destroy(bsg_cmd_cachep); 1019 return ret; 1020 } 1021 1022 MODULE_AUTHOR("Jens Axboe"); 1023 MODULE_DESCRIPTION(BSG_DESCRIPTION); 1024 MODULE_LICENSE("GPL"); 1025 1026 device_initcall(bsg_init); 1027