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