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 /* 449 * If the request generated a negative error number, return it 450 * (providing we aren't already returning an error); if it's 451 * just a protocol response (i.e. non negative), that gets 452 * processed above. 453 */ 454 if (!ret && rq->errors < 0) 455 ret = rq->errors; 456 457 blk_rq_unmap_user(bio); 458 blk_put_request(rq); 459 460 return ret; 461 } 462 463 static int bsg_complete_all_commands(struct bsg_device *bd) 464 { 465 struct bsg_command *bc; 466 int ret, tret; 467 468 dprintk("%s: entered\n", bd->name); 469 470 set_bit(BSG_F_BLOCK, &bd->flags); 471 472 /* 473 * wait for all commands to complete 474 */ 475 ret = 0; 476 do { 477 ret = bsg_io_schedule(bd); 478 /* 479 * look for -ENODATA specifically -- we'll sometimes get 480 * -ERESTARTSYS when we've taken a signal, but we can't 481 * return until we're done freeing the queue, so ignore 482 * it. The signal will get handled when we're done freeing 483 * the bsg_device. 484 */ 485 } while (ret != -ENODATA); 486 487 /* 488 * discard done commands 489 */ 490 ret = 0; 491 do { 492 spin_lock_irq(&bd->lock); 493 if (!bd->queued_cmds) { 494 spin_unlock_irq(&bd->lock); 495 break; 496 } 497 spin_unlock_irq(&bd->lock); 498 499 bc = bsg_get_done_cmd(bd); 500 if (IS_ERR(bc)) 501 break; 502 503 tret = blk_complete_sgv4_hdr_rq(bc->rq, &bc->hdr, bc->bio, 504 bc->bidi_bio); 505 if (!ret) 506 ret = tret; 507 508 bsg_free_command(bc); 509 } while (1); 510 511 return ret; 512 } 513 514 static int 515 __bsg_read(char __user *buf, size_t count, struct bsg_device *bd, 516 const struct iovec *iov, ssize_t *bytes_read) 517 { 518 struct bsg_command *bc; 519 int nr_commands, ret; 520 521 if (count % sizeof(struct sg_io_v4)) 522 return -EINVAL; 523 524 ret = 0; 525 nr_commands = count / sizeof(struct sg_io_v4); 526 while (nr_commands) { 527 bc = bsg_get_done_cmd(bd); 528 if (IS_ERR(bc)) { 529 ret = PTR_ERR(bc); 530 break; 531 } 532 533 /* 534 * this is the only case where we need to copy data back 535 * after completing the request. so do that here, 536 * bsg_complete_work() cannot do that for us 537 */ 538 ret = blk_complete_sgv4_hdr_rq(bc->rq, &bc->hdr, bc->bio, 539 bc->bidi_bio); 540 541 if (copy_to_user(buf, &bc->hdr, sizeof(bc->hdr))) 542 ret = -EFAULT; 543 544 bsg_free_command(bc); 545 546 if (ret) 547 break; 548 549 buf += sizeof(struct sg_io_v4); 550 *bytes_read += sizeof(struct sg_io_v4); 551 nr_commands--; 552 } 553 554 return ret; 555 } 556 557 static inline void bsg_set_block(struct bsg_device *bd, struct file *file) 558 { 559 if (file->f_flags & O_NONBLOCK) 560 clear_bit(BSG_F_BLOCK, &bd->flags); 561 else 562 set_bit(BSG_F_BLOCK, &bd->flags); 563 } 564 565 static inline void bsg_set_write_perm(struct bsg_device *bd, struct file *file) 566 { 567 if (file->f_mode & FMODE_WRITE) 568 set_bit(BSG_F_WRITE_PERM, &bd->flags); 569 else 570 clear_bit(BSG_F_WRITE_PERM, &bd->flags); 571 } 572 573 /* 574 * Check if the error is a "real" error that we should return. 575 */ 576 static inline int err_block_err(int ret) 577 { 578 if (ret && ret != -ENOSPC && ret != -ENODATA && ret != -EAGAIN) 579 return 1; 580 581 return 0; 582 } 583 584 static ssize_t 585 bsg_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) 586 { 587 struct bsg_device *bd = file->private_data; 588 int ret; 589 ssize_t bytes_read; 590 591 dprintk("%s: read %Zd bytes\n", bd->name, count); 592 593 bsg_set_block(bd, file); 594 bytes_read = 0; 595 ret = __bsg_read(buf, count, bd, NULL, &bytes_read); 596 *ppos = bytes_read; 597 598 if (!bytes_read || (bytes_read && err_block_err(ret))) 599 bytes_read = ret; 600 601 return bytes_read; 602 } 603 604 static int __bsg_write(struct bsg_device *bd, const char __user *buf, 605 size_t count, ssize_t *bytes_written) 606 { 607 struct bsg_command *bc; 608 struct request *rq; 609 int ret, nr_commands; 610 611 if (count % sizeof(struct sg_io_v4)) 612 return -EINVAL; 613 614 nr_commands = count / sizeof(struct sg_io_v4); 615 rq = NULL; 616 bc = NULL; 617 ret = 0; 618 while (nr_commands) { 619 struct request_queue *q = bd->queue; 620 621 bc = bsg_alloc_command(bd); 622 if (IS_ERR(bc)) { 623 ret = PTR_ERR(bc); 624 bc = NULL; 625 break; 626 } 627 628 if (copy_from_user(&bc->hdr, buf, sizeof(bc->hdr))) { 629 ret = -EFAULT; 630 break; 631 } 632 633 /* 634 * get a request, fill in the blanks, and add to request queue 635 */ 636 rq = bsg_map_hdr(bd, &bc->hdr); 637 if (IS_ERR(rq)) { 638 ret = PTR_ERR(rq); 639 rq = NULL; 640 break; 641 } 642 643 bsg_add_command(bd, q, bc, rq); 644 bc = NULL; 645 rq = NULL; 646 nr_commands--; 647 buf += sizeof(struct sg_io_v4); 648 *bytes_written += sizeof(struct sg_io_v4); 649 } 650 651 if (bc) 652 bsg_free_command(bc); 653 654 return ret; 655 } 656 657 static ssize_t 658 bsg_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) 659 { 660 struct bsg_device *bd = file->private_data; 661 ssize_t bytes_written; 662 int ret; 663 664 dprintk("%s: write %Zd bytes\n", bd->name, count); 665 666 bsg_set_block(bd, file); 667 bsg_set_write_perm(bd, file); 668 669 bytes_written = 0; 670 ret = __bsg_write(bd, buf, count, &bytes_written); 671 *ppos = bytes_written; 672 673 /* 674 * return bytes written on non-fatal errors 675 */ 676 if (!bytes_written || (bytes_written && err_block_err(ret))) 677 bytes_written = ret; 678 679 dprintk("%s: returning %Zd\n", bd->name, bytes_written); 680 return bytes_written; 681 } 682 683 static struct bsg_device *bsg_alloc_device(void) 684 { 685 struct bsg_device *bd; 686 687 bd = kzalloc(sizeof(struct bsg_device), GFP_KERNEL); 688 if (unlikely(!bd)) 689 return NULL; 690 691 spin_lock_init(&bd->lock); 692 693 bd->max_queue = BSG_DEFAULT_CMDS; 694 695 INIT_LIST_HEAD(&bd->busy_list); 696 INIT_LIST_HEAD(&bd->done_list); 697 INIT_HLIST_NODE(&bd->dev_list); 698 699 init_waitqueue_head(&bd->wq_free); 700 init_waitqueue_head(&bd->wq_done); 701 return bd; 702 } 703 704 static int bsg_put_device(struct bsg_device *bd) 705 { 706 int ret = 0; 707 708 mutex_lock(&bsg_mutex); 709 710 if (!atomic_dec_and_test(&bd->ref_count)) 711 goto out; 712 713 dprintk("%s: tearing down\n", bd->name); 714 715 /* 716 * close can always block 717 */ 718 set_bit(BSG_F_BLOCK, &bd->flags); 719 720 /* 721 * correct error detection baddies here again. it's the responsibility 722 * of the app to properly reap commands before close() if it wants 723 * fool-proof error detection 724 */ 725 ret = bsg_complete_all_commands(bd); 726 727 blk_put_queue(bd->queue); 728 hlist_del(&bd->dev_list); 729 kfree(bd); 730 out: 731 mutex_unlock(&bsg_mutex); 732 return ret; 733 } 734 735 static struct bsg_device *bsg_add_device(struct inode *inode, 736 struct request_queue *rq, 737 struct file *file) 738 { 739 struct bsg_device *bd; 740 #ifdef BSG_DEBUG 741 unsigned char buf[32]; 742 #endif 743 744 bd = bsg_alloc_device(); 745 if (!bd) 746 return ERR_PTR(-ENOMEM); 747 748 bd->queue = rq; 749 kobject_get(&rq->kobj); 750 bsg_set_block(bd, file); 751 752 atomic_set(&bd->ref_count, 1); 753 bd->minor = iminor(inode); 754 mutex_lock(&bsg_mutex); 755 hlist_add_head(&bd->dev_list, bsg_dev_idx_hash(bd->minor)); 756 757 strncpy(bd->name, rq->bsg_dev.class_dev->class_id, sizeof(bd->name) - 1); 758 dprintk("bound to <%s>, max queue %d\n", 759 format_dev_t(buf, inode->i_rdev), bd->max_queue); 760 761 mutex_unlock(&bsg_mutex); 762 return bd; 763 } 764 765 static struct bsg_device *__bsg_get_device(int minor) 766 { 767 struct bsg_device *bd = NULL; 768 struct hlist_node *entry; 769 770 mutex_lock(&bsg_mutex); 771 772 hlist_for_each(entry, bsg_dev_idx_hash(minor)) { 773 bd = hlist_entry(entry, struct bsg_device, dev_list); 774 if (bd->minor == minor) { 775 atomic_inc(&bd->ref_count); 776 break; 777 } 778 779 bd = NULL; 780 } 781 782 mutex_unlock(&bsg_mutex); 783 return bd; 784 } 785 786 static struct bsg_device *bsg_get_device(struct inode *inode, struct file *file) 787 { 788 struct bsg_device *bd; 789 struct bsg_class_device *bcd; 790 791 bd = __bsg_get_device(iminor(inode)); 792 if (bd) 793 return bd; 794 795 /* 796 * find the class device 797 */ 798 mutex_lock(&bsg_mutex); 799 bcd = idr_find(&bsg_minor_idr, iminor(inode)); 800 mutex_unlock(&bsg_mutex); 801 802 if (!bcd) 803 return ERR_PTR(-ENODEV); 804 805 return bsg_add_device(inode, bcd->queue, file); 806 } 807 808 static int bsg_open(struct inode *inode, struct file *file) 809 { 810 struct bsg_device *bd = bsg_get_device(inode, file); 811 812 if (IS_ERR(bd)) 813 return PTR_ERR(bd); 814 815 file->private_data = bd; 816 return 0; 817 } 818 819 static int bsg_release(struct inode *inode, struct file *file) 820 { 821 struct bsg_device *bd = file->private_data; 822 823 file->private_data = NULL; 824 return bsg_put_device(bd); 825 } 826 827 static unsigned int bsg_poll(struct file *file, poll_table *wait) 828 { 829 struct bsg_device *bd = file->private_data; 830 unsigned int mask = 0; 831 832 poll_wait(file, &bd->wq_done, wait); 833 poll_wait(file, &bd->wq_free, wait); 834 835 spin_lock_irq(&bd->lock); 836 if (!list_empty(&bd->done_list)) 837 mask |= POLLIN | POLLRDNORM; 838 if (bd->queued_cmds >= bd->max_queue) 839 mask |= POLLOUT; 840 spin_unlock_irq(&bd->lock); 841 842 return mask; 843 } 844 845 static long bsg_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 846 { 847 struct bsg_device *bd = file->private_data; 848 int __user *uarg = (int __user *) arg; 849 int ret; 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 ret = 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 ret; 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 const 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 if (!bcd->class_dev) 936 return; 937 938 mutex_lock(&bsg_mutex); 939 idr_remove(&bsg_minor_idr, bcd->minor); 940 sysfs_remove_link(&q->kobj, "bsg"); 941 class_device_unregister(bcd->class_dev); 942 put_device(bcd->dev); 943 bcd->class_dev = NULL; 944 bcd->dev = NULL; 945 mutex_unlock(&bsg_mutex); 946 } 947 EXPORT_SYMBOL_GPL(bsg_unregister_queue); 948 949 int bsg_register_queue(struct request_queue *q, struct device *gdev, 950 const char *name) 951 { 952 struct bsg_class_device *bcd; 953 dev_t dev; 954 int ret, minor; 955 struct class_device *class_dev = NULL; 956 const char *devname; 957 958 if (name) 959 devname = name; 960 else 961 devname = gdev->bus_id; 962 963 /* 964 * we need a proper transport to send commands, not a stacked device 965 */ 966 if (!q->request_fn) 967 return 0; 968 969 bcd = &q->bsg_dev; 970 memset(bcd, 0, sizeof(*bcd)); 971 972 mutex_lock(&bsg_mutex); 973 974 ret = idr_pre_get(&bsg_minor_idr, GFP_KERNEL); 975 if (!ret) { 976 ret = -ENOMEM; 977 goto unlock; 978 } 979 980 ret = idr_get_new(&bsg_minor_idr, bcd, &minor); 981 if (ret < 0) 982 goto unlock; 983 984 if (minor >= BSG_MAX_DEVS) { 985 printk(KERN_ERR "bsg: too many bsg devices\n"); 986 ret = -EINVAL; 987 goto remove_idr; 988 } 989 990 bcd->minor = minor; 991 bcd->queue = q; 992 bcd->dev = get_device(gdev); 993 dev = MKDEV(bsg_major, bcd->minor); 994 class_dev = class_device_create(bsg_class, NULL, dev, gdev, "%s", 995 devname); 996 if (IS_ERR(class_dev)) { 997 ret = PTR_ERR(class_dev); 998 goto put_dev; 999 } 1000 bcd->class_dev = class_dev; 1001 1002 if (q->kobj.sd) { 1003 ret = sysfs_create_link(&q->kobj, &bcd->class_dev->kobj, "bsg"); 1004 if (ret) 1005 goto unregister_class_dev; 1006 } 1007 1008 mutex_unlock(&bsg_mutex); 1009 return 0; 1010 1011 unregister_class_dev: 1012 class_device_unregister(class_dev); 1013 put_dev: 1014 put_device(gdev); 1015 remove_idr: 1016 idr_remove(&bsg_minor_idr, minor); 1017 unlock: 1018 mutex_unlock(&bsg_mutex); 1019 return ret; 1020 } 1021 EXPORT_SYMBOL_GPL(bsg_register_queue); 1022 1023 static struct cdev bsg_cdev; 1024 1025 static int __init bsg_init(void) 1026 { 1027 int ret, i; 1028 dev_t devid; 1029 1030 bsg_cmd_cachep = kmem_cache_create("bsg_cmd", 1031 sizeof(struct bsg_command), 0, 0, NULL); 1032 if (!bsg_cmd_cachep) { 1033 printk(KERN_ERR "bsg: failed creating slab cache\n"); 1034 return -ENOMEM; 1035 } 1036 1037 for (i = 0; i < BSG_LIST_ARRAY_SIZE; i++) 1038 INIT_HLIST_HEAD(&bsg_device_list[i]); 1039 1040 bsg_class = class_create(THIS_MODULE, "bsg"); 1041 if (IS_ERR(bsg_class)) { 1042 ret = PTR_ERR(bsg_class); 1043 goto destroy_kmemcache; 1044 } 1045 1046 ret = alloc_chrdev_region(&devid, 0, BSG_MAX_DEVS, "bsg"); 1047 if (ret) 1048 goto destroy_bsg_class; 1049 1050 bsg_major = MAJOR(devid); 1051 1052 cdev_init(&bsg_cdev, &bsg_fops); 1053 ret = cdev_add(&bsg_cdev, MKDEV(bsg_major, 0), BSG_MAX_DEVS); 1054 if (ret) 1055 goto unregister_chrdev; 1056 1057 printk(KERN_INFO BSG_DESCRIPTION " version " BSG_VERSION 1058 " loaded (major %d)\n", bsg_major); 1059 return 0; 1060 unregister_chrdev: 1061 unregister_chrdev_region(MKDEV(bsg_major, 0), BSG_MAX_DEVS); 1062 destroy_bsg_class: 1063 class_destroy(bsg_class); 1064 destroy_kmemcache: 1065 kmem_cache_destroy(bsg_cmd_cachep); 1066 return ret; 1067 } 1068 1069 MODULE_AUTHOR("Jens Axboe"); 1070 MODULE_DESCRIPTION(BSG_DESCRIPTION); 1071 MODULE_LICENSE("GPL"); 1072 1073 device_initcall(bsg_init); 1074