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