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