1 /* 2 * bsg.c - block layer implementation of the sg v3 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 /* 13 * TODO 14 * - Should this get merged, block/scsi_ioctl.c will be migrated into 15 * this file. To keep maintenance down, it's easier to have them 16 * seperated right now. 17 * 18 */ 19 #include <linux/module.h> 20 #include <linux/init.h> 21 #include <linux/file.h> 22 #include <linux/blkdev.h> 23 #include <linux/poll.h> 24 #include <linux/cdev.h> 25 #include <linux/percpu.h> 26 #include <linux/uio.h> 27 #include <linux/bsg.h> 28 29 #include <scsi/scsi.h> 30 #include <scsi/scsi_ioctl.h> 31 #include <scsi/scsi_cmnd.h> 32 #include <scsi/scsi_device.h> 33 #include <scsi/scsi_driver.h> 34 #include <scsi/sg.h> 35 36 #define BSG_DESCRIPTION "Block layer SCSI generic (bsg) driver" 37 #define BSG_VERSION "0.4" 38 39 struct bsg_device { 40 request_queue_t *queue; 41 spinlock_t lock; 42 struct list_head busy_list; 43 struct list_head done_list; 44 struct hlist_node dev_list; 45 atomic_t ref_count; 46 int minor; 47 int queued_cmds; 48 int done_cmds; 49 wait_queue_head_t wq_done; 50 wait_queue_head_t wq_free; 51 char name[BUS_ID_SIZE]; 52 int max_queue; 53 unsigned long flags; 54 }; 55 56 enum { 57 BSG_F_BLOCK = 1, 58 BSG_F_WRITE_PERM = 2, 59 }; 60 61 #define BSG_DEFAULT_CMDS 64 62 #define BSG_MAX_DEVS 32768 63 64 #undef BSG_DEBUG 65 66 #ifdef BSG_DEBUG 67 #define dprintk(fmt, args...) printk(KERN_ERR "%s: " fmt, __FUNCTION__, ##args) 68 #else 69 #define dprintk(fmt, args...) 70 #endif 71 72 static DEFINE_MUTEX(bsg_mutex); 73 static int bsg_device_nr, bsg_minor_idx; 74 75 #define BSG_LIST_ARRAY_SIZE 8 76 static struct hlist_head bsg_device_list[BSG_LIST_ARRAY_SIZE]; 77 78 static struct class *bsg_class; 79 static LIST_HEAD(bsg_class_list); 80 static int bsg_major; 81 82 static struct kmem_cache *bsg_cmd_cachep; 83 84 /* 85 * our internal command type 86 */ 87 struct bsg_command { 88 struct bsg_device *bd; 89 struct list_head list; 90 struct request *rq; 91 struct bio *bio; 92 struct bio *bidi_bio; 93 int err; 94 struct sg_io_v4 hdr; 95 struct sg_io_v4 __user *uhdr; 96 char sense[SCSI_SENSE_BUFFERSIZE]; 97 }; 98 99 static void bsg_free_command(struct bsg_command *bc) 100 { 101 struct bsg_device *bd = bc->bd; 102 unsigned long flags; 103 104 kmem_cache_free(bsg_cmd_cachep, bc); 105 106 spin_lock_irqsave(&bd->lock, flags); 107 bd->queued_cmds--; 108 spin_unlock_irqrestore(&bd->lock, flags); 109 110 wake_up(&bd->wq_free); 111 } 112 113 static struct bsg_command *bsg_alloc_command(struct bsg_device *bd) 114 { 115 struct bsg_command *bc = ERR_PTR(-EINVAL); 116 117 spin_lock_irq(&bd->lock); 118 119 if (bd->queued_cmds >= bd->max_queue) 120 goto out; 121 122 bd->queued_cmds++; 123 spin_unlock_irq(&bd->lock); 124 125 bc = kmem_cache_zalloc(bsg_cmd_cachep, GFP_KERNEL); 126 if (unlikely(!bc)) { 127 spin_lock_irq(&bd->lock); 128 bd->queued_cmds--; 129 bc = ERR_PTR(-ENOMEM); 130 goto out; 131 } 132 133 bc->bd = bd; 134 INIT_LIST_HEAD(&bc->list); 135 dprintk("%s: returning free cmd %p\n", bd->name, bc); 136 return bc; 137 out: 138 spin_unlock_irq(&bd->lock); 139 return bc; 140 } 141 142 static inline struct hlist_head *bsg_dev_idx_hash(int index) 143 { 144 return &bsg_device_list[index & (BSG_LIST_ARRAY_SIZE - 1)]; 145 } 146 147 static int bsg_io_schedule(struct bsg_device *bd) 148 { 149 DEFINE_WAIT(wait); 150 int ret = 0; 151 152 spin_lock_irq(&bd->lock); 153 154 BUG_ON(bd->done_cmds > bd->queued_cmds); 155 156 /* 157 * -ENOSPC or -ENODATA? I'm going for -ENODATA, meaning "I have no 158 * work to do", even though we return -ENOSPC after this same test 159 * during bsg_write() -- there, it means our buffer can't have more 160 * bsg_commands added to it, thus has no space left. 161 */ 162 if (bd->done_cmds == bd->queued_cmds) { 163 ret = -ENODATA; 164 goto unlock; 165 } 166 167 if (!test_bit(BSG_F_BLOCK, &bd->flags)) { 168 ret = -EAGAIN; 169 goto unlock; 170 } 171 172 prepare_to_wait(&bd->wq_done, &wait, TASK_UNINTERRUPTIBLE); 173 spin_unlock_irq(&bd->lock); 174 io_schedule(); 175 finish_wait(&bd->wq_done, &wait); 176 177 return ret; 178 unlock: 179 spin_unlock_irq(&bd->lock); 180 return ret; 181 } 182 183 static int blk_fill_sgv4_hdr_rq(request_queue_t *q, struct request *rq, 184 struct sg_io_v4 *hdr, int has_write_perm) 185 { 186 memset(rq->cmd, 0, BLK_MAX_CDB); /* ATAPI hates garbage after CDB */ 187 188 if (copy_from_user(rq->cmd, (void *)(unsigned long)hdr->request, 189 hdr->request_len)) 190 return -EFAULT; 191 192 if (hdr->subprotocol == BSG_SUB_PROTOCOL_SCSI_CMD) { 193 if (blk_verify_command(rq->cmd, has_write_perm)) 194 return -EPERM; 195 } else if (!capable(CAP_SYS_RAWIO)) 196 return -EPERM; 197 198 /* 199 * fill in request structure 200 */ 201 rq->cmd_len = hdr->request_len; 202 rq->cmd_type = REQ_TYPE_BLOCK_PC; 203 204 rq->timeout = (hdr->timeout * HZ) / 1000; 205 if (!rq->timeout) 206 rq->timeout = q->sg_timeout; 207 if (!rq->timeout) 208 rq->timeout = BLK_DEFAULT_SG_TIMEOUT; 209 210 return 0; 211 } 212 213 /* 214 * Check if sg_io_v4 from user is allowed and valid 215 */ 216 static int 217 bsg_validate_sgv4_hdr(request_queue_t *q, struct sg_io_v4 *hdr, int *rw) 218 { 219 int ret = 0; 220 221 if (hdr->guard != 'Q') 222 return -EINVAL; 223 if (hdr->request_len > BLK_MAX_CDB) 224 return -EINVAL; 225 if (hdr->dout_xfer_len > (q->max_sectors << 9) || 226 hdr->din_xfer_len > (q->max_sectors << 9)) 227 return -EIO; 228 229 switch (hdr->protocol) { 230 case BSG_PROTOCOL_SCSI: 231 switch (hdr->subprotocol) { 232 case BSG_SUB_PROTOCOL_SCSI_CMD: 233 case BSG_SUB_PROTOCOL_SCSI_TRANSPORT: 234 break; 235 default: 236 ret = -EINVAL; 237 } 238 break; 239 default: 240 ret = -EINVAL; 241 } 242 243 *rw = hdr->dout_xfer_len ? WRITE : READ; 244 return ret; 245 } 246 247 /* 248 * map sg_io_v4 to a request. 249 */ 250 static struct request * 251 bsg_map_hdr(struct bsg_device *bd, struct sg_io_v4 *hdr) 252 { 253 request_queue_t *q = bd->queue; 254 struct request *rq, *next_rq = NULL; 255 int ret, rw; 256 unsigned int dxfer_len; 257 void *dxferp = NULL; 258 259 dprintk("map hdr %llx/%u %llx/%u\n", (unsigned long long) hdr->dout_xferp, 260 hdr->dout_xfer_len, (unsigned long long) hdr->din_xferp, 261 hdr->din_xfer_len); 262 263 ret = bsg_validate_sgv4_hdr(q, hdr, &rw); 264 if (ret) 265 return ERR_PTR(ret); 266 267 /* 268 * map scatter-gather elements seperately and string them to request 269 */ 270 rq = blk_get_request(q, rw, GFP_KERNEL); 271 if (!rq) 272 return ERR_PTR(-ENOMEM); 273 ret = blk_fill_sgv4_hdr_rq(q, rq, hdr, test_bit(BSG_F_WRITE_PERM, 274 &bd->flags)); 275 if (ret) 276 goto out; 277 278 if (rw == WRITE && hdr->din_xfer_len) { 279 if (!test_bit(QUEUE_FLAG_BIDI, &q->queue_flags)) { 280 ret = -EOPNOTSUPP; 281 goto out; 282 } 283 284 next_rq = blk_get_request(q, READ, GFP_KERNEL); 285 if (!next_rq) { 286 ret = -ENOMEM; 287 goto out; 288 } 289 rq->next_rq = next_rq; 290 291 dxferp = (void*)(unsigned long)hdr->din_xferp; 292 ret = blk_rq_map_user(q, next_rq, dxferp, hdr->din_xfer_len); 293 if (ret) 294 goto out; 295 } 296 297 if (hdr->dout_xfer_len) { 298 dxfer_len = hdr->dout_xfer_len; 299 dxferp = (void*)(unsigned long)hdr->dout_xferp; 300 } else if (hdr->din_xfer_len) { 301 dxfer_len = hdr->din_xfer_len; 302 dxferp = (void*)(unsigned long)hdr->din_xferp; 303 } else 304 dxfer_len = 0; 305 306 if (dxfer_len) { 307 ret = blk_rq_map_user(q, rq, dxferp, dxfer_len); 308 if (ret) 309 goto out; 310 } 311 return rq; 312 out: 313 blk_put_request(rq); 314 if (next_rq) { 315 blk_rq_unmap_user(next_rq->bio); 316 blk_put_request(next_rq); 317 } 318 return ERR_PTR(ret); 319 } 320 321 /* 322 * async completion call-back from the block layer, when scsi/ide/whatever 323 * calls end_that_request_last() on a request 324 */ 325 static void bsg_rq_end_io(struct request *rq, int uptodate) 326 { 327 struct bsg_command *bc = rq->end_io_data; 328 struct bsg_device *bd = bc->bd; 329 unsigned long flags; 330 331 dprintk("%s: finished rq %p bc %p, bio %p stat %d\n", 332 bd->name, rq, bc, bc->bio, uptodate); 333 334 bc->hdr.duration = jiffies_to_msecs(jiffies - bc->hdr.duration); 335 336 spin_lock_irqsave(&bd->lock, flags); 337 list_move_tail(&bc->list, &bd->done_list); 338 bd->done_cmds++; 339 spin_unlock_irqrestore(&bd->lock, flags); 340 341 wake_up(&bd->wq_done); 342 } 343 344 /* 345 * do final setup of a 'bc' and submit the matching 'rq' to the block 346 * layer for io 347 */ 348 static void bsg_add_command(struct bsg_device *bd, request_queue_t *q, 349 struct bsg_command *bc, struct request *rq) 350 { 351 rq->sense = bc->sense; 352 rq->sense_len = 0; 353 354 /* 355 * add bc command to busy queue and submit rq for io 356 */ 357 bc->rq = rq; 358 bc->bio = rq->bio; 359 if (rq->next_rq) 360 bc->bidi_bio = rq->next_rq->bio; 361 bc->hdr.duration = jiffies; 362 spin_lock_irq(&bd->lock); 363 list_add_tail(&bc->list, &bd->busy_list); 364 spin_unlock_irq(&bd->lock); 365 366 dprintk("%s: queueing rq %p, bc %p\n", bd->name, rq, bc); 367 368 rq->end_io_data = bc; 369 blk_execute_rq_nowait(q, NULL, rq, 1, bsg_rq_end_io); 370 } 371 372 static struct bsg_command *bsg_next_done_cmd(struct bsg_device *bd) 373 { 374 struct bsg_command *bc = NULL; 375 376 spin_lock_irq(&bd->lock); 377 if (bd->done_cmds) { 378 bc = list_entry(bd->done_list.next, struct bsg_command, list); 379 list_del(&bc->list); 380 bd->done_cmds--; 381 } 382 spin_unlock_irq(&bd->lock); 383 384 return bc; 385 } 386 387 /* 388 * Get a finished command from the done list 389 */ 390 static struct bsg_command *bsg_get_done_cmd(struct bsg_device *bd) 391 { 392 struct bsg_command *bc; 393 int ret; 394 395 do { 396 bc = bsg_next_done_cmd(bd); 397 if (bc) 398 break; 399 400 if (!test_bit(BSG_F_BLOCK, &bd->flags)) { 401 bc = ERR_PTR(-EAGAIN); 402 break; 403 } 404 405 ret = wait_event_interruptible(bd->wq_done, bd->done_cmds); 406 if (ret) { 407 bc = ERR_PTR(-ERESTARTSYS); 408 break; 409 } 410 } while (1); 411 412 dprintk("%s: returning done %p\n", bd->name, bc); 413 414 return bc; 415 } 416 417 static int blk_complete_sgv4_hdr_rq(struct request *rq, struct sg_io_v4 *hdr, 418 struct bio *bio, struct bio *bidi_bio) 419 { 420 int ret = 0; 421 422 dprintk("rq %p bio %p %u\n", rq, bio, rq->errors); 423 /* 424 * fill in all the output members 425 */ 426 hdr->device_status = status_byte(rq->errors); 427 hdr->transport_status = host_byte(rq->errors); 428 hdr->driver_status = driver_byte(rq->errors); 429 hdr->info = 0; 430 if (hdr->device_status || hdr->transport_status || hdr->driver_status) 431 hdr->info |= SG_INFO_CHECK; 432 hdr->din_resid = rq->data_len; 433 hdr->response_len = 0; 434 435 if (rq->sense_len && hdr->response) { 436 int len = min_t(unsigned int, hdr->max_response_len, 437 rq->sense_len); 438 439 ret = copy_to_user((void*)(unsigned long)hdr->response, 440 rq->sense, len); 441 if (!ret) 442 hdr->response_len = len; 443 else 444 ret = -EFAULT; 445 } 446 447 if (rq->next_rq) { 448 blk_rq_unmap_user(bidi_bio); 449 blk_put_request(rq->next_rq); 450 } 451 452 blk_rq_unmap_user(bio); 453 blk_put_request(rq); 454 455 return ret; 456 } 457 458 static int bsg_complete_all_commands(struct bsg_device *bd) 459 { 460 struct bsg_command *bc; 461 int ret, tret; 462 463 dprintk("%s: entered\n", bd->name); 464 465 set_bit(BSG_F_BLOCK, &bd->flags); 466 467 /* 468 * wait for all commands to complete 469 */ 470 ret = 0; 471 do { 472 ret = bsg_io_schedule(bd); 473 /* 474 * look for -ENODATA specifically -- we'll sometimes get 475 * -ERESTARTSYS when we've taken a signal, but we can't 476 * return until we're done freeing the queue, so ignore 477 * it. The signal will get handled when we're done freeing 478 * the bsg_device. 479 */ 480 } while (ret != -ENODATA); 481 482 /* 483 * discard done commands 484 */ 485 ret = 0; 486 do { 487 spin_lock_irq(&bd->lock); 488 if (!bd->queued_cmds) { 489 spin_unlock_irq(&bd->lock); 490 break; 491 } 492 spin_unlock_irq(&bd->lock); 493 494 bc = bsg_get_done_cmd(bd); 495 if (IS_ERR(bc)) 496 break; 497 498 tret = blk_complete_sgv4_hdr_rq(bc->rq, &bc->hdr, bc->bio, 499 bc->bidi_bio); 500 if (!ret) 501 ret = tret; 502 503 bsg_free_command(bc); 504 } while (1); 505 506 return ret; 507 } 508 509 static int 510 __bsg_read(char __user *buf, size_t count, struct bsg_device *bd, 511 const struct iovec *iov, ssize_t *bytes_read) 512 { 513 struct bsg_command *bc; 514 int nr_commands, ret; 515 516 if (count % sizeof(struct sg_io_v4)) 517 return -EINVAL; 518 519 ret = 0; 520 nr_commands = count / sizeof(struct sg_io_v4); 521 while (nr_commands) { 522 bc = bsg_get_done_cmd(bd); 523 if (IS_ERR(bc)) { 524 ret = PTR_ERR(bc); 525 break; 526 } 527 528 /* 529 * this is the only case where we need to copy data back 530 * after completing the request. so do that here, 531 * bsg_complete_work() cannot do that for us 532 */ 533 ret = blk_complete_sgv4_hdr_rq(bc->rq, &bc->hdr, bc->bio, 534 bc->bidi_bio); 535 536 if (copy_to_user(buf, &bc->hdr, sizeof(bc->hdr))) 537 ret = -EFAULT; 538 539 bsg_free_command(bc); 540 541 if (ret) 542 break; 543 544 buf += sizeof(struct sg_io_v4); 545 *bytes_read += sizeof(struct sg_io_v4); 546 nr_commands--; 547 } 548 549 return ret; 550 } 551 552 static inline void bsg_set_block(struct bsg_device *bd, struct file *file) 553 { 554 if (file->f_flags & O_NONBLOCK) 555 clear_bit(BSG_F_BLOCK, &bd->flags); 556 else 557 set_bit(BSG_F_BLOCK, &bd->flags); 558 } 559 560 static inline void bsg_set_write_perm(struct bsg_device *bd, struct file *file) 561 { 562 if (file->f_mode & FMODE_WRITE) 563 set_bit(BSG_F_WRITE_PERM, &bd->flags); 564 else 565 clear_bit(BSG_F_WRITE_PERM, &bd->flags); 566 } 567 568 /* 569 * Check if the error is a "real" error that we should return. 570 */ 571 static inline int err_block_err(int ret) 572 { 573 if (ret && ret != -ENOSPC && ret != -ENODATA && ret != -EAGAIN) 574 return 1; 575 576 return 0; 577 } 578 579 static ssize_t 580 bsg_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) 581 { 582 struct bsg_device *bd = file->private_data; 583 int ret; 584 ssize_t bytes_read; 585 586 dprintk("%s: read %Zd bytes\n", bd->name, count); 587 588 bsg_set_block(bd, file); 589 bytes_read = 0; 590 ret = __bsg_read(buf, count, bd, NULL, &bytes_read); 591 *ppos = bytes_read; 592 593 if (!bytes_read || (bytes_read && err_block_err(ret))) 594 bytes_read = ret; 595 596 return bytes_read; 597 } 598 599 static int __bsg_write(struct bsg_device *bd, const char __user *buf, 600 size_t count, ssize_t *bytes_written) 601 { 602 struct bsg_command *bc; 603 struct request *rq; 604 int ret, nr_commands; 605 606 if (count % sizeof(struct sg_io_v4)) 607 return -EINVAL; 608 609 nr_commands = count / sizeof(struct sg_io_v4); 610 rq = NULL; 611 bc = NULL; 612 ret = 0; 613 while (nr_commands) { 614 request_queue_t *q = bd->queue; 615 616 bc = bsg_alloc_command(bd); 617 if (IS_ERR(bc)) { 618 ret = PTR_ERR(bc); 619 bc = NULL; 620 break; 621 } 622 623 bc->uhdr = (struct sg_io_v4 __user *) buf; 624 if (copy_from_user(&bc->hdr, buf, sizeof(bc->hdr))) { 625 ret = -EFAULT; 626 break; 627 } 628 629 /* 630 * get a request, fill in the blanks, and add to request queue 631 */ 632 rq = bsg_map_hdr(bd, &bc->hdr); 633 if (IS_ERR(rq)) { 634 ret = PTR_ERR(rq); 635 rq = NULL; 636 break; 637 } 638 639 bsg_add_command(bd, q, bc, rq); 640 bc = NULL; 641 rq = NULL; 642 nr_commands--; 643 buf += sizeof(struct sg_io_v4); 644 *bytes_written += sizeof(struct sg_io_v4); 645 } 646 647 if (bc) 648 bsg_free_command(bc); 649 650 return ret; 651 } 652 653 static ssize_t 654 bsg_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) 655 { 656 struct bsg_device *bd = file->private_data; 657 ssize_t bytes_written; 658 int ret; 659 660 dprintk("%s: write %Zd bytes\n", bd->name, count); 661 662 bsg_set_block(bd, file); 663 bsg_set_write_perm(bd, file); 664 665 bytes_written = 0; 666 ret = __bsg_write(bd, buf, count, &bytes_written); 667 *ppos = bytes_written; 668 669 /* 670 * return bytes written on non-fatal errors 671 */ 672 if (!bytes_written || (bytes_written && err_block_err(ret))) 673 bytes_written = ret; 674 675 dprintk("%s: returning %Zd\n", bd->name, bytes_written); 676 return bytes_written; 677 } 678 679 static struct bsg_device *bsg_alloc_device(void) 680 { 681 struct bsg_device *bd; 682 683 bd = kzalloc(sizeof(struct bsg_device), GFP_KERNEL); 684 if (unlikely(!bd)) 685 return NULL; 686 687 spin_lock_init(&bd->lock); 688 689 bd->max_queue = BSG_DEFAULT_CMDS; 690 691 INIT_LIST_HEAD(&bd->busy_list); 692 INIT_LIST_HEAD(&bd->done_list); 693 INIT_HLIST_NODE(&bd->dev_list); 694 695 init_waitqueue_head(&bd->wq_free); 696 init_waitqueue_head(&bd->wq_done); 697 return bd; 698 } 699 700 static int bsg_put_device(struct bsg_device *bd) 701 { 702 int ret = 0; 703 704 mutex_lock(&bsg_mutex); 705 706 if (!atomic_dec_and_test(&bd->ref_count)) 707 goto out; 708 709 dprintk("%s: tearing down\n", bd->name); 710 711 /* 712 * close can always block 713 */ 714 set_bit(BSG_F_BLOCK, &bd->flags); 715 716 /* 717 * correct error detection baddies here again. it's the responsibility 718 * of the app to properly reap commands before close() if it wants 719 * fool-proof error detection 720 */ 721 ret = bsg_complete_all_commands(bd); 722 723 blk_put_queue(bd->queue); 724 hlist_del(&bd->dev_list); 725 kfree(bd); 726 out: 727 mutex_unlock(&bsg_mutex); 728 return ret; 729 } 730 731 static struct bsg_device *bsg_add_device(struct inode *inode, 732 struct request_queue *rq, 733 struct file *file) 734 { 735 struct bsg_device *bd; 736 #ifdef BSG_DEBUG 737 unsigned char buf[32]; 738 #endif 739 740 bd = bsg_alloc_device(); 741 if (!bd) 742 return ERR_PTR(-ENOMEM); 743 744 bd->queue = rq; 745 kobject_get(&rq->kobj); 746 bsg_set_block(bd, file); 747 748 atomic_set(&bd->ref_count, 1); 749 bd->minor = iminor(inode); 750 mutex_lock(&bsg_mutex); 751 hlist_add_head(&bd->dev_list, bsg_dev_idx_hash(bd->minor)); 752 753 strncpy(bd->name, rq->bsg_dev.class_dev->class_id, sizeof(bd->name) - 1); 754 dprintk("bound to <%s>, max queue %d\n", 755 format_dev_t(buf, inode->i_rdev), bd->max_queue); 756 757 mutex_unlock(&bsg_mutex); 758 return bd; 759 } 760 761 static struct bsg_device *__bsg_get_device(int minor) 762 { 763 struct bsg_device *bd = NULL; 764 struct hlist_node *entry; 765 766 mutex_lock(&bsg_mutex); 767 768 hlist_for_each(entry, bsg_dev_idx_hash(minor)) { 769 bd = hlist_entry(entry, struct bsg_device, dev_list); 770 if (bd->minor == minor) { 771 atomic_inc(&bd->ref_count); 772 break; 773 } 774 775 bd = NULL; 776 } 777 778 mutex_unlock(&bsg_mutex); 779 return bd; 780 } 781 782 static struct bsg_device *bsg_get_device(struct inode *inode, struct file *file) 783 { 784 struct bsg_device *bd = __bsg_get_device(iminor(inode)); 785 struct bsg_class_device *bcd, *__bcd; 786 787 if (bd) 788 return bd; 789 790 /* 791 * find the class device 792 */ 793 bcd = NULL; 794 mutex_lock(&bsg_mutex); 795 list_for_each_entry(__bcd, &bsg_class_list, list) { 796 if (__bcd->minor == iminor(inode)) { 797 bcd = __bcd; 798 break; 799 } 800 } 801 mutex_unlock(&bsg_mutex); 802 803 if (!bcd) 804 return ERR_PTR(-ENODEV); 805 806 return bsg_add_device(inode, bcd->queue, file); 807 } 808 809 static int bsg_open(struct inode *inode, struct file *file) 810 { 811 struct bsg_device *bd = bsg_get_device(inode, file); 812 813 if (IS_ERR(bd)) 814 return PTR_ERR(bd); 815 816 file->private_data = bd; 817 return 0; 818 } 819 820 static int bsg_release(struct inode *inode, struct file *file) 821 { 822 struct bsg_device *bd = file->private_data; 823 824 file->private_data = NULL; 825 return bsg_put_device(bd); 826 } 827 828 static unsigned int bsg_poll(struct file *file, poll_table *wait) 829 { 830 struct bsg_device *bd = file->private_data; 831 unsigned int mask = 0; 832 833 poll_wait(file, &bd->wq_done, wait); 834 poll_wait(file, &bd->wq_free, wait); 835 836 spin_lock_irq(&bd->lock); 837 if (!list_empty(&bd->done_list)) 838 mask |= POLLIN | POLLRDNORM; 839 if (bd->queued_cmds >= bd->max_queue) 840 mask |= POLLOUT; 841 spin_unlock_irq(&bd->lock); 842 843 return mask; 844 } 845 846 static long bsg_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 847 { 848 struct bsg_device *bd = file->private_data; 849 int __user *uarg = (int __user *) arg; 850 851 switch (cmd) { 852 /* 853 * our own ioctls 854 */ 855 case SG_GET_COMMAND_Q: 856 return put_user(bd->max_queue, uarg); 857 case SG_SET_COMMAND_Q: { 858 int queue; 859 860 if (get_user(queue, uarg)) 861 return -EFAULT; 862 if (queue < 1) 863 return -EINVAL; 864 865 spin_lock_irq(&bd->lock); 866 bd->max_queue = queue; 867 spin_unlock_irq(&bd->lock); 868 return 0; 869 } 870 871 /* 872 * SCSI/sg ioctls 873 */ 874 case SG_GET_VERSION_NUM: 875 case SCSI_IOCTL_GET_IDLUN: 876 case SCSI_IOCTL_GET_BUS_NUMBER: 877 case SG_SET_TIMEOUT: 878 case SG_GET_TIMEOUT: 879 case SG_GET_RESERVED_SIZE: 880 case SG_SET_RESERVED_SIZE: 881 case SG_EMULATED_HOST: 882 case SCSI_IOCTL_SEND_COMMAND: { 883 void __user *uarg = (void __user *) arg; 884 return scsi_cmd_ioctl(file, bd->queue, NULL, cmd, uarg); 885 } 886 case SG_IO: { 887 struct request *rq; 888 struct bio *bio, *bidi_bio = NULL; 889 struct sg_io_v4 hdr; 890 891 if (copy_from_user(&hdr, uarg, sizeof(hdr))) 892 return -EFAULT; 893 894 rq = bsg_map_hdr(bd, &hdr); 895 if (IS_ERR(rq)) 896 return PTR_ERR(rq); 897 898 bio = rq->bio; 899 if (rq->next_rq) 900 bidi_bio = rq->next_rq->bio; 901 blk_execute_rq(bd->queue, NULL, rq, 0); 902 blk_complete_sgv4_hdr_rq(rq, &hdr, bio, bidi_bio); 903 904 if (copy_to_user(uarg, &hdr, sizeof(hdr))) 905 return -EFAULT; 906 907 return 0; 908 } 909 /* 910 * block device ioctls 911 */ 912 default: 913 #if 0 914 return ioctl_by_bdev(bd->bdev, cmd, arg); 915 #else 916 return -ENOTTY; 917 #endif 918 } 919 } 920 921 static struct file_operations bsg_fops = { 922 .read = bsg_read, 923 .write = bsg_write, 924 .poll = bsg_poll, 925 .open = bsg_open, 926 .release = bsg_release, 927 .unlocked_ioctl = bsg_ioctl, 928 .owner = THIS_MODULE, 929 }; 930 931 void bsg_unregister_queue(struct request_queue *q) 932 { 933 struct bsg_class_device *bcd = &q->bsg_dev; 934 935 WARN_ON(!bcd->class_dev); 936 937 mutex_lock(&bsg_mutex); 938 sysfs_remove_link(&q->kobj, "bsg"); 939 class_device_destroy(bsg_class, MKDEV(bsg_major, bcd->minor)); 940 bcd->class_dev = NULL; 941 list_del_init(&bcd->list); 942 bsg_device_nr--; 943 mutex_unlock(&bsg_mutex); 944 } 945 EXPORT_SYMBOL_GPL(bsg_unregister_queue); 946 947 int bsg_register_queue(struct request_queue *q, const char *name) 948 { 949 struct bsg_class_device *bcd, *__bcd; 950 dev_t dev; 951 int ret = -EMFILE; 952 struct class_device *class_dev = NULL; 953 954 /* 955 * we need a proper transport to send commands, not a stacked device 956 */ 957 if (!q->request_fn) 958 return 0; 959 960 bcd = &q->bsg_dev; 961 memset(bcd, 0, sizeof(*bcd)); 962 INIT_LIST_HEAD(&bcd->list); 963 964 mutex_lock(&bsg_mutex); 965 if (bsg_device_nr == BSG_MAX_DEVS) { 966 printk(KERN_ERR "bsg: too many bsg devices\n"); 967 goto err; 968 } 969 970 retry: 971 list_for_each_entry(__bcd, &bsg_class_list, list) { 972 if (__bcd->minor == bsg_minor_idx) { 973 bsg_minor_idx++; 974 if (bsg_minor_idx == BSG_MAX_DEVS) 975 bsg_minor_idx = 0; 976 goto retry; 977 } 978 } 979 980 bcd->minor = bsg_minor_idx++; 981 if (bsg_minor_idx == BSG_MAX_DEVS) 982 bsg_minor_idx = 0; 983 984 bcd->queue = q; 985 dev = MKDEV(bsg_major, bcd->minor); 986 class_dev = class_device_create(bsg_class, NULL, dev, bcd->dev, "%s", name); 987 if (IS_ERR(class_dev)) { 988 ret = PTR_ERR(class_dev); 989 goto err; 990 } 991 bcd->class_dev = class_dev; 992 993 if (q->kobj.sd) { 994 ret = sysfs_create_link(&q->kobj, &bcd->class_dev->kobj, "bsg"); 995 if (ret) 996 goto err; 997 } 998 999 list_add_tail(&bcd->list, &bsg_class_list); 1000 bsg_device_nr++; 1001 1002 mutex_unlock(&bsg_mutex); 1003 return 0; 1004 err: 1005 if (class_dev) 1006 class_device_destroy(bsg_class, MKDEV(bsg_major, bcd->minor)); 1007 mutex_unlock(&bsg_mutex); 1008 return ret; 1009 } 1010 EXPORT_SYMBOL_GPL(bsg_register_queue); 1011 1012 static int bsg_add(struct class_device *cl_dev, struct class_interface *cl_intf) 1013 { 1014 int ret; 1015 struct scsi_device *sdp = to_scsi_device(cl_dev->dev); 1016 struct request_queue *rq = sdp->request_queue; 1017 1018 if (rq->kobj.parent) 1019 ret = bsg_register_queue(rq, kobject_name(rq->kobj.parent)); 1020 else 1021 ret = bsg_register_queue(rq, kobject_name(&sdp->sdev_gendev.kobj)); 1022 return ret; 1023 } 1024 1025 static void bsg_remove(struct class_device *cl_dev, struct class_interface *cl_intf) 1026 { 1027 bsg_unregister_queue(to_scsi_device(cl_dev->dev)->request_queue); 1028 } 1029 1030 static struct class_interface bsg_intf = { 1031 .add = bsg_add, 1032 .remove = bsg_remove, 1033 }; 1034 1035 static struct cdev bsg_cdev = { 1036 .kobj = {.name = "bsg", }, 1037 .owner = THIS_MODULE, 1038 }; 1039 1040 static int __init bsg_init(void) 1041 { 1042 int ret, i; 1043 dev_t devid; 1044 1045 bsg_cmd_cachep = kmem_cache_create("bsg_cmd", 1046 sizeof(struct bsg_command), 0, 0, NULL, NULL); 1047 if (!bsg_cmd_cachep) { 1048 printk(KERN_ERR "bsg: failed creating slab cache\n"); 1049 return -ENOMEM; 1050 } 1051 1052 for (i = 0; i < BSG_LIST_ARRAY_SIZE; i++) 1053 INIT_HLIST_HEAD(&bsg_device_list[i]); 1054 1055 bsg_class = class_create(THIS_MODULE, "bsg"); 1056 if (IS_ERR(bsg_class)) { 1057 ret = PTR_ERR(bsg_class); 1058 goto destroy_kmemcache; 1059 } 1060 1061 ret = alloc_chrdev_region(&devid, 0, BSG_MAX_DEVS, "bsg"); 1062 if (ret) 1063 goto destroy_bsg_class; 1064 1065 bsg_major = MAJOR(devid); 1066 1067 cdev_init(&bsg_cdev, &bsg_fops); 1068 ret = cdev_add(&bsg_cdev, MKDEV(bsg_major, 0), BSG_MAX_DEVS); 1069 if (ret) 1070 goto unregister_chrdev; 1071 1072 ret = scsi_register_interface(&bsg_intf); 1073 if (ret) 1074 goto remove_cdev; 1075 1076 printk(KERN_INFO BSG_DESCRIPTION " version " BSG_VERSION 1077 " loaded (major %d)\n", bsg_major); 1078 return 0; 1079 remove_cdev: 1080 printk(KERN_ERR "bsg: failed register scsi interface %d\n", ret); 1081 cdev_del(&bsg_cdev); 1082 unregister_chrdev: 1083 unregister_chrdev_region(MKDEV(bsg_major, 0), BSG_MAX_DEVS); 1084 destroy_bsg_class: 1085 class_destroy(bsg_class); 1086 destroy_kmemcache: 1087 kmem_cache_destroy(bsg_cmd_cachep); 1088 return ret; 1089 } 1090 1091 MODULE_AUTHOR("Jens Axboe"); 1092 MODULE_DESCRIPTION(BSG_DESCRIPTION); 1093 MODULE_LICENSE("GPL"); 1094 1095 device_initcall(bsg_init); 1096