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 struct bsg_device { 36 struct request_queue *queue; 37 spinlock_t lock; 38 struct list_head busy_list; 39 struct list_head done_list; 40 struct hlist_node dev_list; 41 atomic_t ref_count; 42 int queued_cmds; 43 int done_cmds; 44 wait_queue_head_t wq_done; 45 wait_queue_head_t wq_free; 46 char name[20]; 47 int max_queue; 48 unsigned long flags; 49 }; 50 51 enum { 52 BSG_F_BLOCK = 1, 53 }; 54 55 #define BSG_DEFAULT_CMDS 64 56 #define BSG_MAX_DEVS 32768 57 58 #undef BSG_DEBUG 59 60 #ifdef BSG_DEBUG 61 #define dprintk(fmt, args...) printk(KERN_ERR "%s: " fmt, __func__, ##args) 62 #else 63 #define dprintk(fmt, args...) 64 #endif 65 66 static DEFINE_MUTEX(bsg_mutex); 67 static DEFINE_IDR(bsg_minor_idr); 68 69 #define BSG_LIST_ARRAY_SIZE 8 70 static struct hlist_head bsg_device_list[BSG_LIST_ARRAY_SIZE]; 71 72 static struct class *bsg_class; 73 static int bsg_major; 74 75 static struct kmem_cache *bsg_cmd_cachep; 76 77 /* 78 * our internal command type 79 */ 80 struct bsg_command { 81 struct bsg_device *bd; 82 struct list_head list; 83 struct request *rq; 84 struct bio *bio; 85 struct bio *bidi_bio; 86 int err; 87 struct sg_io_v4 hdr; 88 char sense[SCSI_SENSE_BUFFERSIZE]; 89 }; 90 91 static void bsg_free_command(struct bsg_command *bc) 92 { 93 struct bsg_device *bd = bc->bd; 94 unsigned long flags; 95 96 kmem_cache_free(bsg_cmd_cachep, bc); 97 98 spin_lock_irqsave(&bd->lock, flags); 99 bd->queued_cmds--; 100 spin_unlock_irqrestore(&bd->lock, flags); 101 102 wake_up(&bd->wq_free); 103 } 104 105 static struct bsg_command *bsg_alloc_command(struct bsg_device *bd) 106 { 107 struct bsg_command *bc = ERR_PTR(-EINVAL); 108 109 spin_lock_irq(&bd->lock); 110 111 if (bd->queued_cmds >= bd->max_queue) 112 goto out; 113 114 bd->queued_cmds++; 115 spin_unlock_irq(&bd->lock); 116 117 bc = kmem_cache_zalloc(bsg_cmd_cachep, GFP_KERNEL); 118 if (unlikely(!bc)) { 119 spin_lock_irq(&bd->lock); 120 bd->queued_cmds--; 121 bc = ERR_PTR(-ENOMEM); 122 goto out; 123 } 124 125 bc->bd = bd; 126 INIT_LIST_HEAD(&bc->list); 127 dprintk("%s: returning free cmd %p\n", bd->name, bc); 128 return bc; 129 out: 130 spin_unlock_irq(&bd->lock); 131 return bc; 132 } 133 134 static inline struct hlist_head *bsg_dev_idx_hash(int index) 135 { 136 return &bsg_device_list[index & (BSG_LIST_ARRAY_SIZE - 1)]; 137 } 138 139 static int bsg_io_schedule(struct bsg_device *bd) 140 { 141 DEFINE_WAIT(wait); 142 int ret = 0; 143 144 spin_lock_irq(&bd->lock); 145 146 BUG_ON(bd->done_cmds > bd->queued_cmds); 147 148 /* 149 * -ENOSPC or -ENODATA? I'm going for -ENODATA, meaning "I have no 150 * work to do", even though we return -ENOSPC after this same test 151 * during bsg_write() -- there, it means our buffer can't have more 152 * bsg_commands added to it, thus has no space left. 153 */ 154 if (bd->done_cmds == bd->queued_cmds) { 155 ret = -ENODATA; 156 goto unlock; 157 } 158 159 if (!test_bit(BSG_F_BLOCK, &bd->flags)) { 160 ret = -EAGAIN; 161 goto unlock; 162 } 163 164 prepare_to_wait(&bd->wq_done, &wait, TASK_UNINTERRUPTIBLE); 165 spin_unlock_irq(&bd->lock); 166 io_schedule(); 167 finish_wait(&bd->wq_done, &wait); 168 169 return ret; 170 unlock: 171 spin_unlock_irq(&bd->lock); 172 return ret; 173 } 174 175 static int blk_fill_sgv4_hdr_rq(struct request_queue *q, struct request *rq, 176 struct sg_io_v4 *hdr, struct bsg_device *bd, 177 fmode_t has_write_perm) 178 { 179 if (hdr->request_len > BLK_MAX_CDB) { 180 rq->cmd = kzalloc(hdr->request_len, GFP_KERNEL); 181 if (!rq->cmd) 182 return -ENOMEM; 183 } 184 185 if (copy_from_user(rq->cmd, (void __user *)(unsigned long)hdr->request, 186 hdr->request_len)) 187 return -EFAULT; 188 189 if (hdr->subprotocol == BSG_SUB_PROTOCOL_SCSI_CMD) { 190 if (blk_verify_command(rq->cmd, has_write_perm)) 191 return -EPERM; 192 } else if (!capable(CAP_SYS_RAWIO)) 193 return -EPERM; 194 195 /* 196 * fill in request structure 197 */ 198 rq->cmd_len = hdr->request_len; 199 200 rq->timeout = msecs_to_jiffies(hdr->timeout); 201 if (!rq->timeout) 202 rq->timeout = q->sg_timeout; 203 if (!rq->timeout) 204 rq->timeout = BLK_DEFAULT_SG_TIMEOUT; 205 if (rq->timeout < BLK_MIN_SG_TIMEOUT) 206 rq->timeout = BLK_MIN_SG_TIMEOUT; 207 208 return 0; 209 } 210 211 /* 212 * Check if sg_io_v4 from user is allowed and valid 213 */ 214 static int 215 bsg_validate_sgv4_hdr(struct request_queue *q, struct sg_io_v4 *hdr, int *rw) 216 { 217 int ret = 0; 218 219 if (hdr->guard != 'Q') 220 return -EINVAL; 221 222 switch (hdr->protocol) { 223 case BSG_PROTOCOL_SCSI: 224 switch (hdr->subprotocol) { 225 case BSG_SUB_PROTOCOL_SCSI_CMD: 226 case BSG_SUB_PROTOCOL_SCSI_TRANSPORT: 227 break; 228 default: 229 ret = -EINVAL; 230 } 231 break; 232 default: 233 ret = -EINVAL; 234 } 235 236 *rw = hdr->dout_xfer_len ? WRITE : READ; 237 return ret; 238 } 239 240 /* 241 * map sg_io_v4 to a request. 242 */ 243 static struct request * 244 bsg_map_hdr(struct bsg_device *bd, struct sg_io_v4 *hdr, fmode_t has_write_perm, 245 u8 *sense) 246 { 247 struct request_queue *q = bd->queue; 248 struct request *rq, *next_rq = NULL; 249 int ret, rw; 250 unsigned int dxfer_len; 251 void __user *dxferp = NULL; 252 struct bsg_class_device *bcd = &q->bsg_dev; 253 254 /* if the LLD has been removed then the bsg_unregister_queue will 255 * eventually be called and the class_dev was freed, so we can no 256 * longer use this request_queue. Return no such address. 257 */ 258 if (!bcd->class_dev) 259 return ERR_PTR(-ENXIO); 260 261 dprintk("map hdr %llx/%u %llx/%u\n", (unsigned long long) hdr->dout_xferp, 262 hdr->dout_xfer_len, (unsigned long long) hdr->din_xferp, 263 hdr->din_xfer_len); 264 265 ret = bsg_validate_sgv4_hdr(q, hdr, &rw); 266 if (ret) 267 return ERR_PTR(ret); 268 269 /* 270 * map scatter-gather elements separately and string them to request 271 */ 272 rq = blk_get_request(q, rw, GFP_KERNEL); 273 if (!rq) 274 return ERR_PTR(-ENOMEM); 275 blk_rq_set_block_pc(rq); 276 277 ret = blk_fill_sgv4_hdr_rq(q, rq, hdr, bd, has_write_perm); 278 if (ret) 279 goto out; 280 281 if (rw == WRITE && hdr->din_xfer_len) { 282 if (!test_bit(QUEUE_FLAG_BIDI, &q->queue_flags)) { 283 ret = -EOPNOTSUPP; 284 goto out; 285 } 286 287 next_rq = blk_get_request(q, READ, GFP_KERNEL); 288 if (!next_rq) { 289 ret = -ENOMEM; 290 goto out; 291 } 292 rq->next_rq = next_rq; 293 next_rq->cmd_type = rq->cmd_type; 294 295 dxferp = (void __user *)(unsigned long)hdr->din_xferp; 296 ret = blk_rq_map_user(q, next_rq, NULL, dxferp, 297 hdr->din_xfer_len, GFP_KERNEL); 298 if (ret) 299 goto out; 300 } 301 302 if (hdr->dout_xfer_len) { 303 dxfer_len = hdr->dout_xfer_len; 304 dxferp = (void __user *)(unsigned long)hdr->dout_xferp; 305 } else if (hdr->din_xfer_len) { 306 dxfer_len = hdr->din_xfer_len; 307 dxferp = (void __user *)(unsigned long)hdr->din_xferp; 308 } else 309 dxfer_len = 0; 310 311 if (dxfer_len) { 312 ret = blk_rq_map_user(q, rq, NULL, dxferp, dxfer_len, 313 GFP_KERNEL); 314 if (ret) 315 goto out; 316 } 317 318 rq->sense = sense; 319 rq->sense_len = 0; 320 321 return rq; 322 out: 323 if (rq->cmd != rq->__cmd) 324 kfree(rq->cmd); 325 blk_put_request(rq); 326 if (next_rq) { 327 blk_rq_unmap_user(next_rq->bio); 328 blk_put_request(next_rq); 329 } 330 return ERR_PTR(ret); 331 } 332 333 /* 334 * async completion call-back from the block layer, when scsi/ide/whatever 335 * calls end_that_request_last() on a request 336 */ 337 static void bsg_rq_end_io(struct request *rq, int uptodate) 338 { 339 struct bsg_command *bc = rq->end_io_data; 340 struct bsg_device *bd = bc->bd; 341 unsigned long flags; 342 343 dprintk("%s: finished rq %p bc %p, bio %p stat %d\n", 344 bd->name, rq, bc, bc->bio, uptodate); 345 346 bc->hdr.duration = jiffies_to_msecs(jiffies - bc->hdr.duration); 347 348 spin_lock_irqsave(&bd->lock, flags); 349 list_move_tail(&bc->list, &bd->done_list); 350 bd->done_cmds++; 351 spin_unlock_irqrestore(&bd->lock, flags); 352 353 wake_up(&bd->wq_done); 354 } 355 356 /* 357 * do final setup of a 'bc' and submit the matching 'rq' to the block 358 * layer for io 359 */ 360 static void bsg_add_command(struct bsg_device *bd, struct request_queue *q, 361 struct bsg_command *bc, struct request *rq) 362 { 363 int at_head = (0 == (bc->hdr.flags & BSG_FLAG_Q_AT_TAIL)); 364 365 /* 366 * add bc command to busy queue and submit rq for io 367 */ 368 bc->rq = rq; 369 bc->bio = rq->bio; 370 if (rq->next_rq) 371 bc->bidi_bio = rq->next_rq->bio; 372 bc->hdr.duration = jiffies; 373 spin_lock_irq(&bd->lock); 374 list_add_tail(&bc->list, &bd->busy_list); 375 spin_unlock_irq(&bd->lock); 376 377 dprintk("%s: queueing rq %p, bc %p\n", bd->name, rq, bc); 378 379 rq->end_io_data = bc; 380 blk_execute_rq_nowait(q, NULL, rq, at_head, bsg_rq_end_io); 381 } 382 383 static struct bsg_command *bsg_next_done_cmd(struct bsg_device *bd) 384 { 385 struct bsg_command *bc = NULL; 386 387 spin_lock_irq(&bd->lock); 388 if (bd->done_cmds) { 389 bc = list_first_entry(&bd->done_list, struct bsg_command, list); 390 list_del(&bc->list); 391 bd->done_cmds--; 392 } 393 spin_unlock_irq(&bd->lock); 394 395 return bc; 396 } 397 398 /* 399 * Get a finished command from the done list 400 */ 401 static struct bsg_command *bsg_get_done_cmd(struct bsg_device *bd) 402 { 403 struct bsg_command *bc; 404 int ret; 405 406 do { 407 bc = bsg_next_done_cmd(bd); 408 if (bc) 409 break; 410 411 if (!test_bit(BSG_F_BLOCK, &bd->flags)) { 412 bc = ERR_PTR(-EAGAIN); 413 break; 414 } 415 416 ret = wait_event_interruptible(bd->wq_done, bd->done_cmds); 417 if (ret) { 418 bc = ERR_PTR(-ERESTARTSYS); 419 break; 420 } 421 } while (1); 422 423 dprintk("%s: returning done %p\n", bd->name, bc); 424 425 return bc; 426 } 427 428 static int blk_complete_sgv4_hdr_rq(struct request *rq, struct sg_io_v4 *hdr, 429 struct bio *bio, struct bio *bidi_bio) 430 { 431 int ret = 0; 432 433 dprintk("rq %p bio %p 0x%x\n", rq, bio, rq->errors); 434 /* 435 * fill in all the output members 436 */ 437 hdr->device_status = rq->errors & 0xff; 438 hdr->transport_status = host_byte(rq->errors); 439 hdr->driver_status = driver_byte(rq->errors); 440 hdr->info = 0; 441 if (hdr->device_status || hdr->transport_status || hdr->driver_status) 442 hdr->info |= SG_INFO_CHECK; 443 hdr->response_len = 0; 444 445 if (rq->sense_len && hdr->response) { 446 int len = min_t(unsigned int, hdr->max_response_len, 447 rq->sense_len); 448 449 ret = copy_to_user((void __user *)(unsigned long)hdr->response, 450 rq->sense, len); 451 if (!ret) 452 hdr->response_len = len; 453 else 454 ret = -EFAULT; 455 } 456 457 if (rq->next_rq) { 458 hdr->dout_resid = rq->resid_len; 459 hdr->din_resid = rq->next_rq->resid_len; 460 blk_rq_unmap_user(bidi_bio); 461 blk_put_request(rq->next_rq); 462 } else if (rq_data_dir(rq) == READ) 463 hdr->din_resid = rq->resid_len; 464 else 465 hdr->dout_resid = rq->resid_len; 466 467 /* 468 * If the request generated a negative error number, return it 469 * (providing we aren't already returning an error); if it's 470 * just a protocol response (i.e. non negative), that gets 471 * processed above. 472 */ 473 if (!ret && rq->errors < 0) 474 ret = rq->errors; 475 476 blk_rq_unmap_user(bio); 477 if (rq->cmd != rq->__cmd) 478 kfree(rq->cmd); 479 blk_put_request(rq); 480 481 return ret; 482 } 483 484 static int bsg_complete_all_commands(struct bsg_device *bd) 485 { 486 struct bsg_command *bc; 487 int ret, tret; 488 489 dprintk("%s: entered\n", bd->name); 490 491 /* 492 * wait for all commands to complete 493 */ 494 ret = 0; 495 do { 496 ret = bsg_io_schedule(bd); 497 /* 498 * look for -ENODATA specifically -- we'll sometimes get 499 * -ERESTARTSYS when we've taken a signal, but we can't 500 * return until we're done freeing the queue, so ignore 501 * it. The signal will get handled when we're done freeing 502 * the bsg_device. 503 */ 504 } while (ret != -ENODATA); 505 506 /* 507 * discard done commands 508 */ 509 ret = 0; 510 do { 511 spin_lock_irq(&bd->lock); 512 if (!bd->queued_cmds) { 513 spin_unlock_irq(&bd->lock); 514 break; 515 } 516 spin_unlock_irq(&bd->lock); 517 518 bc = bsg_get_done_cmd(bd); 519 if (IS_ERR(bc)) 520 break; 521 522 tret = blk_complete_sgv4_hdr_rq(bc->rq, &bc->hdr, bc->bio, 523 bc->bidi_bio); 524 if (!ret) 525 ret = tret; 526 527 bsg_free_command(bc); 528 } while (1); 529 530 return ret; 531 } 532 533 static int 534 __bsg_read(char __user *buf, size_t count, struct bsg_device *bd, 535 const struct iovec *iov, ssize_t *bytes_read) 536 { 537 struct bsg_command *bc; 538 int nr_commands, ret; 539 540 if (count % sizeof(struct sg_io_v4)) 541 return -EINVAL; 542 543 ret = 0; 544 nr_commands = count / sizeof(struct sg_io_v4); 545 while (nr_commands) { 546 bc = bsg_get_done_cmd(bd); 547 if (IS_ERR(bc)) { 548 ret = PTR_ERR(bc); 549 break; 550 } 551 552 /* 553 * this is the only case where we need to copy data back 554 * after completing the request. so do that here, 555 * bsg_complete_work() cannot do that for us 556 */ 557 ret = blk_complete_sgv4_hdr_rq(bc->rq, &bc->hdr, bc->bio, 558 bc->bidi_bio); 559 560 if (copy_to_user(buf, &bc->hdr, sizeof(bc->hdr))) 561 ret = -EFAULT; 562 563 bsg_free_command(bc); 564 565 if (ret) 566 break; 567 568 buf += sizeof(struct sg_io_v4); 569 *bytes_read += sizeof(struct sg_io_v4); 570 nr_commands--; 571 } 572 573 return ret; 574 } 575 576 static inline void bsg_set_block(struct bsg_device *bd, struct file *file) 577 { 578 if (file->f_flags & O_NONBLOCK) 579 clear_bit(BSG_F_BLOCK, &bd->flags); 580 else 581 set_bit(BSG_F_BLOCK, &bd->flags); 582 } 583 584 /* 585 * Check if the error is a "real" error that we should return. 586 */ 587 static inline int err_block_err(int ret) 588 { 589 if (ret && ret != -ENOSPC && ret != -ENODATA && ret != -EAGAIN) 590 return 1; 591 592 return 0; 593 } 594 595 static ssize_t 596 bsg_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) 597 { 598 struct bsg_device *bd = file->private_data; 599 int ret; 600 ssize_t bytes_read; 601 602 dprintk("%s: read %Zd bytes\n", bd->name, count); 603 604 bsg_set_block(bd, file); 605 606 bytes_read = 0; 607 ret = __bsg_read(buf, count, bd, NULL, &bytes_read); 608 *ppos = bytes_read; 609 610 if (!bytes_read || err_block_err(ret)) 611 bytes_read = ret; 612 613 return bytes_read; 614 } 615 616 static int __bsg_write(struct bsg_device *bd, const char __user *buf, 617 size_t count, ssize_t *bytes_written, 618 fmode_t has_write_perm) 619 { 620 struct bsg_command *bc; 621 struct request *rq; 622 int ret, nr_commands; 623 624 if (count % sizeof(struct sg_io_v4)) 625 return -EINVAL; 626 627 nr_commands = count / sizeof(struct sg_io_v4); 628 rq = NULL; 629 bc = NULL; 630 ret = 0; 631 while (nr_commands) { 632 struct request_queue *q = bd->queue; 633 634 bc = bsg_alloc_command(bd); 635 if (IS_ERR(bc)) { 636 ret = PTR_ERR(bc); 637 bc = NULL; 638 break; 639 } 640 641 if (copy_from_user(&bc->hdr, buf, sizeof(bc->hdr))) { 642 ret = -EFAULT; 643 break; 644 } 645 646 /* 647 * get a request, fill in the blanks, and add to request queue 648 */ 649 rq = bsg_map_hdr(bd, &bc->hdr, has_write_perm, bc->sense); 650 if (IS_ERR(rq)) { 651 ret = PTR_ERR(rq); 652 rq = NULL; 653 break; 654 } 655 656 bsg_add_command(bd, q, bc, rq); 657 bc = NULL; 658 rq = NULL; 659 nr_commands--; 660 buf += sizeof(struct sg_io_v4); 661 *bytes_written += sizeof(struct sg_io_v4); 662 } 663 664 if (bc) 665 bsg_free_command(bc); 666 667 return ret; 668 } 669 670 static ssize_t 671 bsg_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) 672 { 673 struct bsg_device *bd = file->private_data; 674 ssize_t bytes_written; 675 int ret; 676 677 dprintk("%s: write %Zd bytes\n", bd->name, count); 678 679 bsg_set_block(bd, file); 680 681 bytes_written = 0; 682 ret = __bsg_write(bd, buf, count, &bytes_written, 683 file->f_mode & FMODE_WRITE); 684 685 *ppos = bytes_written; 686 687 /* 688 * return bytes written on non-fatal errors 689 */ 690 if (!bytes_written || err_block_err(ret)) 691 bytes_written = ret; 692 693 dprintk("%s: returning %Zd\n", bd->name, bytes_written); 694 return bytes_written; 695 } 696 697 static struct bsg_device *bsg_alloc_device(void) 698 { 699 struct bsg_device *bd; 700 701 bd = kzalloc(sizeof(struct bsg_device), GFP_KERNEL); 702 if (unlikely(!bd)) 703 return NULL; 704 705 spin_lock_init(&bd->lock); 706 707 bd->max_queue = BSG_DEFAULT_CMDS; 708 709 INIT_LIST_HEAD(&bd->busy_list); 710 INIT_LIST_HEAD(&bd->done_list); 711 INIT_HLIST_NODE(&bd->dev_list); 712 713 init_waitqueue_head(&bd->wq_free); 714 init_waitqueue_head(&bd->wq_done); 715 return bd; 716 } 717 718 static void bsg_kref_release_function(struct kref *kref) 719 { 720 struct bsg_class_device *bcd = 721 container_of(kref, struct bsg_class_device, ref); 722 struct device *parent = bcd->parent; 723 724 if (bcd->release) 725 bcd->release(bcd->parent); 726 727 put_device(parent); 728 } 729 730 static int bsg_put_device(struct bsg_device *bd) 731 { 732 int ret = 0, do_free; 733 struct request_queue *q = bd->queue; 734 735 mutex_lock(&bsg_mutex); 736 737 do_free = atomic_dec_and_test(&bd->ref_count); 738 if (!do_free) { 739 mutex_unlock(&bsg_mutex); 740 goto out; 741 } 742 743 hlist_del(&bd->dev_list); 744 mutex_unlock(&bsg_mutex); 745 746 dprintk("%s: tearing down\n", bd->name); 747 748 /* 749 * close can always block 750 */ 751 set_bit(BSG_F_BLOCK, &bd->flags); 752 753 /* 754 * correct error detection baddies here again. it's the responsibility 755 * of the app to properly reap commands before close() if it wants 756 * fool-proof error detection 757 */ 758 ret = bsg_complete_all_commands(bd); 759 760 kfree(bd); 761 out: 762 kref_put(&q->bsg_dev.ref, bsg_kref_release_function); 763 if (do_free) 764 blk_put_queue(q); 765 return ret; 766 } 767 768 static struct bsg_device *bsg_add_device(struct inode *inode, 769 struct request_queue *rq, 770 struct file *file) 771 { 772 struct bsg_device *bd; 773 #ifdef BSG_DEBUG 774 unsigned char buf[32]; 775 #endif 776 if (!blk_get_queue(rq)) 777 return ERR_PTR(-ENXIO); 778 779 bd = bsg_alloc_device(); 780 if (!bd) { 781 blk_put_queue(rq); 782 return ERR_PTR(-ENOMEM); 783 } 784 785 bd->queue = rq; 786 787 bsg_set_block(bd, file); 788 789 atomic_set(&bd->ref_count, 1); 790 mutex_lock(&bsg_mutex); 791 hlist_add_head(&bd->dev_list, bsg_dev_idx_hash(iminor(inode))); 792 793 strncpy(bd->name, dev_name(rq->bsg_dev.class_dev), sizeof(bd->name) - 1); 794 dprintk("bound to <%s>, max queue %d\n", 795 format_dev_t(buf, inode->i_rdev), bd->max_queue); 796 797 mutex_unlock(&bsg_mutex); 798 return bd; 799 } 800 801 static struct bsg_device *__bsg_get_device(int minor, struct request_queue *q) 802 { 803 struct bsg_device *bd; 804 805 mutex_lock(&bsg_mutex); 806 807 hlist_for_each_entry(bd, bsg_dev_idx_hash(minor), dev_list) { 808 if (bd->queue == q) { 809 atomic_inc(&bd->ref_count); 810 goto found; 811 } 812 } 813 bd = NULL; 814 found: 815 mutex_unlock(&bsg_mutex); 816 return bd; 817 } 818 819 static struct bsg_device *bsg_get_device(struct inode *inode, struct file *file) 820 { 821 struct bsg_device *bd; 822 struct bsg_class_device *bcd; 823 824 /* 825 * find the class device 826 */ 827 mutex_lock(&bsg_mutex); 828 bcd = idr_find(&bsg_minor_idr, iminor(inode)); 829 if (bcd) 830 kref_get(&bcd->ref); 831 mutex_unlock(&bsg_mutex); 832 833 if (!bcd) 834 return ERR_PTR(-ENODEV); 835 836 bd = __bsg_get_device(iminor(inode), bcd->queue); 837 if (bd) 838 return bd; 839 840 bd = bsg_add_device(inode, bcd->queue, file); 841 if (IS_ERR(bd)) 842 kref_put(&bcd->ref, bsg_kref_release_function); 843 844 return bd; 845 } 846 847 static int bsg_open(struct inode *inode, struct file *file) 848 { 849 struct bsg_device *bd; 850 851 bd = bsg_get_device(inode, file); 852 853 if (IS_ERR(bd)) 854 return PTR_ERR(bd); 855 856 file->private_data = bd; 857 return 0; 858 } 859 860 static int bsg_release(struct inode *inode, struct file *file) 861 { 862 struct bsg_device *bd = file->private_data; 863 864 file->private_data = NULL; 865 return bsg_put_device(bd); 866 } 867 868 static unsigned int bsg_poll(struct file *file, poll_table *wait) 869 { 870 struct bsg_device *bd = file->private_data; 871 unsigned int mask = 0; 872 873 poll_wait(file, &bd->wq_done, wait); 874 poll_wait(file, &bd->wq_free, wait); 875 876 spin_lock_irq(&bd->lock); 877 if (!list_empty(&bd->done_list)) 878 mask |= POLLIN | POLLRDNORM; 879 if (bd->queued_cmds < bd->max_queue) 880 mask |= POLLOUT; 881 spin_unlock_irq(&bd->lock); 882 883 return mask; 884 } 885 886 static long bsg_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 887 { 888 struct bsg_device *bd = file->private_data; 889 int __user *uarg = (int __user *) arg; 890 int ret; 891 892 switch (cmd) { 893 /* 894 * our own ioctls 895 */ 896 case SG_GET_COMMAND_Q: 897 return put_user(bd->max_queue, uarg); 898 case SG_SET_COMMAND_Q: { 899 int queue; 900 901 if (get_user(queue, uarg)) 902 return -EFAULT; 903 if (queue < 1) 904 return -EINVAL; 905 906 spin_lock_irq(&bd->lock); 907 bd->max_queue = queue; 908 spin_unlock_irq(&bd->lock); 909 return 0; 910 } 911 912 /* 913 * SCSI/sg ioctls 914 */ 915 case SG_GET_VERSION_NUM: 916 case SCSI_IOCTL_GET_IDLUN: 917 case SCSI_IOCTL_GET_BUS_NUMBER: 918 case SG_SET_TIMEOUT: 919 case SG_GET_TIMEOUT: 920 case SG_GET_RESERVED_SIZE: 921 case SG_SET_RESERVED_SIZE: 922 case SG_EMULATED_HOST: 923 case SCSI_IOCTL_SEND_COMMAND: { 924 void __user *uarg = (void __user *) arg; 925 return scsi_cmd_ioctl(bd->queue, NULL, file->f_mode, cmd, uarg); 926 } 927 case SG_IO: { 928 struct request *rq; 929 struct bio *bio, *bidi_bio = NULL; 930 struct sg_io_v4 hdr; 931 int at_head; 932 u8 sense[SCSI_SENSE_BUFFERSIZE]; 933 934 if (copy_from_user(&hdr, uarg, sizeof(hdr))) 935 return -EFAULT; 936 937 rq = bsg_map_hdr(bd, &hdr, file->f_mode & FMODE_WRITE, sense); 938 if (IS_ERR(rq)) 939 return PTR_ERR(rq); 940 941 bio = rq->bio; 942 if (rq->next_rq) 943 bidi_bio = rq->next_rq->bio; 944 945 at_head = (0 == (hdr.flags & BSG_FLAG_Q_AT_TAIL)); 946 blk_execute_rq(bd->queue, NULL, rq, at_head); 947 ret = blk_complete_sgv4_hdr_rq(rq, &hdr, bio, bidi_bio); 948 949 if (copy_to_user(uarg, &hdr, sizeof(hdr))) 950 return -EFAULT; 951 952 return ret; 953 } 954 /* 955 * block device ioctls 956 */ 957 default: 958 #if 0 959 return ioctl_by_bdev(bd->bdev, cmd, arg); 960 #else 961 return -ENOTTY; 962 #endif 963 } 964 } 965 966 static const struct file_operations bsg_fops = { 967 .read = bsg_read, 968 .write = bsg_write, 969 .poll = bsg_poll, 970 .open = bsg_open, 971 .release = bsg_release, 972 .unlocked_ioctl = bsg_ioctl, 973 .owner = THIS_MODULE, 974 .llseek = default_llseek, 975 }; 976 977 void bsg_unregister_queue(struct request_queue *q) 978 { 979 struct bsg_class_device *bcd = &q->bsg_dev; 980 981 if (!bcd->class_dev) 982 return; 983 984 mutex_lock(&bsg_mutex); 985 idr_remove(&bsg_minor_idr, bcd->minor); 986 if (q->kobj.sd) 987 sysfs_remove_link(&q->kobj, "bsg"); 988 device_unregister(bcd->class_dev); 989 bcd->class_dev = NULL; 990 kref_put(&bcd->ref, bsg_kref_release_function); 991 mutex_unlock(&bsg_mutex); 992 } 993 EXPORT_SYMBOL_GPL(bsg_unregister_queue); 994 995 int bsg_register_queue(struct request_queue *q, struct device *parent, 996 const char *name, void (*release)(struct device *)) 997 { 998 struct bsg_class_device *bcd; 999 dev_t dev; 1000 int ret; 1001 struct device *class_dev = NULL; 1002 const char *devname; 1003 1004 if (name) 1005 devname = name; 1006 else 1007 devname = dev_name(parent); 1008 1009 /* 1010 * we need a proper transport to send commands, not a stacked device 1011 */ 1012 if (!queue_is_rq_based(q)) 1013 return 0; 1014 1015 bcd = &q->bsg_dev; 1016 memset(bcd, 0, sizeof(*bcd)); 1017 1018 mutex_lock(&bsg_mutex); 1019 1020 ret = idr_alloc(&bsg_minor_idr, bcd, 0, BSG_MAX_DEVS, GFP_KERNEL); 1021 if (ret < 0) { 1022 if (ret == -ENOSPC) { 1023 printk(KERN_ERR "bsg: too many bsg devices\n"); 1024 ret = -EINVAL; 1025 } 1026 goto unlock; 1027 } 1028 1029 bcd->minor = ret; 1030 bcd->queue = q; 1031 bcd->parent = get_device(parent); 1032 bcd->release = release; 1033 kref_init(&bcd->ref); 1034 dev = MKDEV(bsg_major, bcd->minor); 1035 class_dev = device_create(bsg_class, parent, dev, NULL, "%s", devname); 1036 if (IS_ERR(class_dev)) { 1037 ret = PTR_ERR(class_dev); 1038 goto put_dev; 1039 } 1040 bcd->class_dev = class_dev; 1041 1042 if (q->kobj.sd) { 1043 ret = sysfs_create_link(&q->kobj, &bcd->class_dev->kobj, "bsg"); 1044 if (ret) 1045 goto unregister_class_dev; 1046 } 1047 1048 mutex_unlock(&bsg_mutex); 1049 return 0; 1050 1051 unregister_class_dev: 1052 device_unregister(class_dev); 1053 put_dev: 1054 put_device(parent); 1055 idr_remove(&bsg_minor_idr, bcd->minor); 1056 unlock: 1057 mutex_unlock(&bsg_mutex); 1058 return ret; 1059 } 1060 EXPORT_SYMBOL_GPL(bsg_register_queue); 1061 1062 static struct cdev bsg_cdev; 1063 1064 static char *bsg_devnode(struct device *dev, umode_t *mode) 1065 { 1066 return kasprintf(GFP_KERNEL, "bsg/%s", dev_name(dev)); 1067 } 1068 1069 static int __init bsg_init(void) 1070 { 1071 int ret, i; 1072 dev_t devid; 1073 1074 bsg_cmd_cachep = kmem_cache_create("bsg_cmd", 1075 sizeof(struct bsg_command), 0, 0, NULL); 1076 if (!bsg_cmd_cachep) { 1077 printk(KERN_ERR "bsg: failed creating slab cache\n"); 1078 return -ENOMEM; 1079 } 1080 1081 for (i = 0; i < BSG_LIST_ARRAY_SIZE; i++) 1082 INIT_HLIST_HEAD(&bsg_device_list[i]); 1083 1084 bsg_class = class_create(THIS_MODULE, "bsg"); 1085 if (IS_ERR(bsg_class)) { 1086 ret = PTR_ERR(bsg_class); 1087 goto destroy_kmemcache; 1088 } 1089 bsg_class->devnode = bsg_devnode; 1090 1091 ret = alloc_chrdev_region(&devid, 0, BSG_MAX_DEVS, "bsg"); 1092 if (ret) 1093 goto destroy_bsg_class; 1094 1095 bsg_major = MAJOR(devid); 1096 1097 cdev_init(&bsg_cdev, &bsg_fops); 1098 ret = cdev_add(&bsg_cdev, MKDEV(bsg_major, 0), BSG_MAX_DEVS); 1099 if (ret) 1100 goto unregister_chrdev; 1101 1102 printk(KERN_INFO BSG_DESCRIPTION " version " BSG_VERSION 1103 " loaded (major %d)\n", bsg_major); 1104 return 0; 1105 unregister_chrdev: 1106 unregister_chrdev_region(MKDEV(bsg_major, 0), BSG_MAX_DEVS); 1107 destroy_bsg_class: 1108 class_destroy(bsg_class); 1109 destroy_kmemcache: 1110 kmem_cache_destroy(bsg_cmd_cachep); 1111 return ret; 1112 } 1113 1114 MODULE_AUTHOR("Jens Axboe"); 1115 MODULE_DESCRIPTION(BSG_DESCRIPTION); 1116 MODULE_LICENSE("GPL"); 1117 1118 device_initcall(bsg_init); 1119