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 #include <linux/smp_lock.h> 23 24 #include <scsi/scsi.h> 25 #include <scsi/scsi_ioctl.h> 26 #include <scsi/scsi_cmnd.h> 27 #include <scsi/scsi_device.h> 28 #include <scsi/scsi_driver.h> 29 #include <scsi/sg.h> 30 31 #define BSG_DESCRIPTION "Block layer SCSI generic (bsg) driver" 32 #define BSG_VERSION "0.4" 33 34 struct bsg_device { 35 struct request_queue *queue; 36 spinlock_t lock; 37 struct list_head busy_list; 38 struct list_head done_list; 39 struct hlist_node dev_list; 40 atomic_t ref_count; 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 }; 53 54 #define BSG_DEFAULT_CMDS 64 55 #define BSG_MAX_DEVS 32768 56 57 #undef BSG_DEBUG 58 59 #ifdef BSG_DEBUG 60 #define dprintk(fmt, args...) printk(KERN_ERR "%s: " fmt, __func__, ##args) 61 #else 62 #define dprintk(fmt, args...) 63 #endif 64 65 static DEFINE_MUTEX(bsg_mutex); 66 static DEFINE_IDR(bsg_minor_idr); 67 68 #define BSG_LIST_ARRAY_SIZE 8 69 static struct hlist_head bsg_device_list[BSG_LIST_ARRAY_SIZE]; 70 71 static struct class *bsg_class; 72 static int bsg_major; 73 74 static struct kmem_cache *bsg_cmd_cachep; 75 76 /* 77 * our internal command type 78 */ 79 struct bsg_command { 80 struct bsg_device *bd; 81 struct list_head list; 82 struct request *rq; 83 struct bio *bio; 84 struct bio *bidi_bio; 85 int err; 86 struct sg_io_v4 hdr; 87 char sense[SCSI_SENSE_BUFFERSIZE]; 88 }; 89 90 static void bsg_free_command(struct bsg_command *bc) 91 { 92 struct bsg_device *bd = bc->bd; 93 unsigned long flags; 94 95 kmem_cache_free(bsg_cmd_cachep, bc); 96 97 spin_lock_irqsave(&bd->lock, flags); 98 bd->queued_cmds--; 99 spin_unlock_irqrestore(&bd->lock, flags); 100 101 wake_up(&bd->wq_free); 102 } 103 104 static struct bsg_command *bsg_alloc_command(struct bsg_device *bd) 105 { 106 struct bsg_command *bc = ERR_PTR(-EINVAL); 107 108 spin_lock_irq(&bd->lock); 109 110 if (bd->queued_cmds >= bd->max_queue) 111 goto out; 112 113 bd->queued_cmds++; 114 spin_unlock_irq(&bd->lock); 115 116 bc = kmem_cache_zalloc(bsg_cmd_cachep, GFP_KERNEL); 117 if (unlikely(!bc)) { 118 spin_lock_irq(&bd->lock); 119 bd->queued_cmds--; 120 bc = ERR_PTR(-ENOMEM); 121 goto out; 122 } 123 124 bc->bd = bd; 125 INIT_LIST_HEAD(&bc->list); 126 dprintk("%s: returning free cmd %p\n", bd->name, bc); 127 return bc; 128 out: 129 spin_unlock_irq(&bd->lock); 130 return bc; 131 } 132 133 static inline struct hlist_head *bsg_dev_idx_hash(int index) 134 { 135 return &bsg_device_list[index & (BSG_LIST_ARRAY_SIZE - 1)]; 136 } 137 138 static int bsg_io_schedule(struct bsg_device *bd) 139 { 140 DEFINE_WAIT(wait); 141 int ret = 0; 142 143 spin_lock_irq(&bd->lock); 144 145 BUG_ON(bd->done_cmds > bd->queued_cmds); 146 147 /* 148 * -ENOSPC or -ENODATA? I'm going for -ENODATA, meaning "I have no 149 * work to do", even though we return -ENOSPC after this same test 150 * during bsg_write() -- there, it means our buffer can't have more 151 * bsg_commands added to it, thus has no space left. 152 */ 153 if (bd->done_cmds == bd->queued_cmds) { 154 ret = -ENODATA; 155 goto unlock; 156 } 157 158 if (!test_bit(BSG_F_BLOCK, &bd->flags)) { 159 ret = -EAGAIN; 160 goto unlock; 161 } 162 163 prepare_to_wait(&bd->wq_done, &wait, TASK_UNINTERRUPTIBLE); 164 spin_unlock_irq(&bd->lock); 165 io_schedule(); 166 finish_wait(&bd->wq_done, &wait); 167 168 return ret; 169 unlock: 170 spin_unlock_irq(&bd->lock); 171 return ret; 172 } 173 174 static int blk_fill_sgv4_hdr_rq(struct request_queue *q, struct request *rq, 175 struct sg_io_v4 *hdr, struct bsg_device *bd, 176 int has_write_perm) 177 { 178 if (hdr->request_len > BLK_MAX_CDB) { 179 rq->cmd = kzalloc(hdr->request_len, GFP_KERNEL); 180 if (!rq->cmd) 181 return -ENOMEM; 182 } 183 184 if (copy_from_user(rq->cmd, (void *)(unsigned long)hdr->request, 185 hdr->request_len)) 186 return -EFAULT; 187 188 if (hdr->subprotocol == BSG_SUB_PROTOCOL_SCSI_CMD) { 189 if (blk_verify_command(&q->cmd_filter, rq->cmd, has_write_perm)) 190 return -EPERM; 191 } else if (!capable(CAP_SYS_RAWIO)) 192 return -EPERM; 193 194 /* 195 * fill in request structure 196 */ 197 rq->cmd_len = hdr->request_len; 198 rq->cmd_type = REQ_TYPE_BLOCK_PC; 199 200 rq->timeout = (hdr->timeout * HZ) / 1000; 201 if (!rq->timeout) 202 rq->timeout = q->sg_timeout; 203 if (!rq->timeout) 204 rq->timeout = BLK_DEFAULT_SG_TIMEOUT; 205 206 return 0; 207 } 208 209 /* 210 * Check if sg_io_v4 from user is allowed and valid 211 */ 212 static int 213 bsg_validate_sgv4_hdr(struct request_queue *q, struct sg_io_v4 *hdr, int *rw) 214 { 215 int ret = 0; 216 217 if (hdr->guard != 'Q') 218 return -EINVAL; 219 if (hdr->dout_xfer_len > (q->max_sectors << 9) || 220 hdr->din_xfer_len > (q->max_sectors << 9)) 221 return -EIO; 222 223 switch (hdr->protocol) { 224 case BSG_PROTOCOL_SCSI: 225 switch (hdr->subprotocol) { 226 case BSG_SUB_PROTOCOL_SCSI_CMD: 227 case BSG_SUB_PROTOCOL_SCSI_TRANSPORT: 228 break; 229 default: 230 ret = -EINVAL; 231 } 232 break; 233 default: 234 ret = -EINVAL; 235 } 236 237 *rw = hdr->dout_xfer_len ? WRITE : READ; 238 return ret; 239 } 240 241 /* 242 * map sg_io_v4 to a request. 243 */ 244 static struct request * 245 bsg_map_hdr(struct bsg_device *bd, struct sg_io_v4 *hdr, int has_write_perm) 246 { 247 struct request_queue *q = bd->queue; 248 struct request *rq, *next_rq = NULL; 249 int ret, rw; 250 unsigned int dxfer_len; 251 void *dxferp = NULL; 252 253 dprintk("map hdr %llx/%u %llx/%u\n", (unsigned long long) hdr->dout_xferp, 254 hdr->dout_xfer_len, (unsigned long long) hdr->din_xferp, 255 hdr->din_xfer_len); 256 257 ret = bsg_validate_sgv4_hdr(q, hdr, &rw); 258 if (ret) 259 return ERR_PTR(ret); 260 261 /* 262 * map scatter-gather elements seperately and string them to request 263 */ 264 rq = blk_get_request(q, rw, GFP_KERNEL); 265 if (!rq) 266 return ERR_PTR(-ENOMEM); 267 ret = blk_fill_sgv4_hdr_rq(q, rq, hdr, bd, has_write_perm); 268 if (ret) 269 goto out; 270 271 if (rw == WRITE && hdr->din_xfer_len) { 272 if (!test_bit(QUEUE_FLAG_BIDI, &q->queue_flags)) { 273 ret = -EOPNOTSUPP; 274 goto out; 275 } 276 277 next_rq = blk_get_request(q, READ, GFP_KERNEL); 278 if (!next_rq) { 279 ret = -ENOMEM; 280 goto out; 281 } 282 rq->next_rq = next_rq; 283 next_rq->cmd_type = rq->cmd_type; 284 285 dxferp = (void*)(unsigned long)hdr->din_xferp; 286 ret = blk_rq_map_user(q, next_rq, dxferp, hdr->din_xfer_len); 287 if (ret) 288 goto out; 289 } 290 291 if (hdr->dout_xfer_len) { 292 dxfer_len = hdr->dout_xfer_len; 293 dxferp = (void*)(unsigned long)hdr->dout_xferp; 294 } else if (hdr->din_xfer_len) { 295 dxfer_len = hdr->din_xfer_len; 296 dxferp = (void*)(unsigned long)hdr->din_xferp; 297 } else 298 dxfer_len = 0; 299 300 if (dxfer_len) { 301 ret = blk_rq_map_user(q, rq, dxferp, dxfer_len); 302 if (ret) 303 goto out; 304 } 305 return rq; 306 out: 307 if (rq->cmd != rq->__cmd) 308 kfree(rq->cmd); 309 blk_put_request(rq); 310 if (next_rq) { 311 blk_rq_unmap_user(next_rq->bio); 312 blk_put_request(next_rq); 313 } 314 return ERR_PTR(ret); 315 } 316 317 /* 318 * async completion call-back from the block layer, when scsi/ide/whatever 319 * calls end_that_request_last() on a request 320 */ 321 static void bsg_rq_end_io(struct request *rq, int uptodate) 322 { 323 struct bsg_command *bc = rq->end_io_data; 324 struct bsg_device *bd = bc->bd; 325 unsigned long flags; 326 327 dprintk("%s: finished rq %p bc %p, bio %p stat %d\n", 328 bd->name, rq, bc, bc->bio, uptodate); 329 330 bc->hdr.duration = jiffies_to_msecs(jiffies - bc->hdr.duration); 331 332 spin_lock_irqsave(&bd->lock, flags); 333 list_move_tail(&bc->list, &bd->done_list); 334 bd->done_cmds++; 335 spin_unlock_irqrestore(&bd->lock, flags); 336 337 wake_up(&bd->wq_done); 338 } 339 340 /* 341 * do final setup of a 'bc' and submit the matching 'rq' to the block 342 * layer for io 343 */ 344 static void bsg_add_command(struct bsg_device *bd, struct request_queue *q, 345 struct bsg_command *bc, struct request *rq) 346 { 347 rq->sense = bc->sense; 348 rq->sense_len = 0; 349 350 /* 351 * add bc command to busy queue and submit rq for io 352 */ 353 bc->rq = rq; 354 bc->bio = rq->bio; 355 if (rq->next_rq) 356 bc->bidi_bio = rq->next_rq->bio; 357 bc->hdr.duration = jiffies; 358 spin_lock_irq(&bd->lock); 359 list_add_tail(&bc->list, &bd->busy_list); 360 spin_unlock_irq(&bd->lock); 361 362 dprintk("%s: queueing rq %p, bc %p\n", bd->name, rq, bc); 363 364 rq->end_io_data = bc; 365 blk_execute_rq_nowait(q, NULL, rq, 1, bsg_rq_end_io); 366 } 367 368 static struct bsg_command *bsg_next_done_cmd(struct bsg_device *bd) 369 { 370 struct bsg_command *bc = NULL; 371 372 spin_lock_irq(&bd->lock); 373 if (bd->done_cmds) { 374 bc = list_first_entry(&bd->done_list, struct bsg_command, list); 375 list_del(&bc->list); 376 bd->done_cmds--; 377 } 378 spin_unlock_irq(&bd->lock); 379 380 return bc; 381 } 382 383 /* 384 * Get a finished command from the done list 385 */ 386 static struct bsg_command *bsg_get_done_cmd(struct bsg_device *bd) 387 { 388 struct bsg_command *bc; 389 int ret; 390 391 do { 392 bc = bsg_next_done_cmd(bd); 393 if (bc) 394 break; 395 396 if (!test_bit(BSG_F_BLOCK, &bd->flags)) { 397 bc = ERR_PTR(-EAGAIN); 398 break; 399 } 400 401 ret = wait_event_interruptible(bd->wq_done, bd->done_cmds); 402 if (ret) { 403 bc = ERR_PTR(-ERESTARTSYS); 404 break; 405 } 406 } while (1); 407 408 dprintk("%s: returning done %p\n", bd->name, bc); 409 410 return bc; 411 } 412 413 static int blk_complete_sgv4_hdr_rq(struct request *rq, struct sg_io_v4 *hdr, 414 struct bio *bio, struct bio *bidi_bio) 415 { 416 int ret = 0; 417 418 dprintk("rq %p bio %p %u\n", rq, bio, rq->errors); 419 /* 420 * fill in all the output members 421 */ 422 hdr->device_status = status_byte(rq->errors); 423 hdr->transport_status = host_byte(rq->errors); 424 hdr->driver_status = driver_byte(rq->errors); 425 hdr->info = 0; 426 if (hdr->device_status || hdr->transport_status || hdr->driver_status) 427 hdr->info |= SG_INFO_CHECK; 428 hdr->response_len = 0; 429 430 if (rq->sense_len && hdr->response) { 431 int len = min_t(unsigned int, hdr->max_response_len, 432 rq->sense_len); 433 434 ret = copy_to_user((void*)(unsigned long)hdr->response, 435 rq->sense, len); 436 if (!ret) 437 hdr->response_len = len; 438 else 439 ret = -EFAULT; 440 } 441 442 if (rq->next_rq) { 443 hdr->dout_resid = rq->data_len; 444 hdr->din_resid = rq->next_rq->data_len; 445 blk_rq_unmap_user(bidi_bio); 446 blk_put_request(rq->next_rq); 447 } else if (rq_data_dir(rq) == READ) 448 hdr->din_resid = rq->data_len; 449 else 450 hdr->dout_resid = rq->data_len; 451 452 /* 453 * If the request generated a negative error number, return it 454 * (providing we aren't already returning an error); if it's 455 * just a protocol response (i.e. non negative), that gets 456 * processed above. 457 */ 458 if (!ret && rq->errors < 0) 459 ret = rq->errors; 460 461 blk_rq_unmap_user(bio); 462 if (rq->cmd != rq->__cmd) 463 kfree(rq->cmd); 464 blk_put_request(rq); 465 466 return ret; 467 } 468 469 static int bsg_complete_all_commands(struct bsg_device *bd) 470 { 471 struct bsg_command *bc; 472 int ret, tret; 473 474 dprintk("%s: entered\n", bd->name); 475 476 /* 477 * wait for all commands to complete 478 */ 479 ret = 0; 480 do { 481 ret = bsg_io_schedule(bd); 482 /* 483 * look for -ENODATA specifically -- we'll sometimes get 484 * -ERESTARTSYS when we've taken a signal, but we can't 485 * return until we're done freeing the queue, so ignore 486 * it. The signal will get handled when we're done freeing 487 * the bsg_device. 488 */ 489 } while (ret != -ENODATA); 490 491 /* 492 * discard done commands 493 */ 494 ret = 0; 495 do { 496 spin_lock_irq(&bd->lock); 497 if (!bd->queued_cmds) { 498 spin_unlock_irq(&bd->lock); 499 break; 500 } 501 spin_unlock_irq(&bd->lock); 502 503 bc = bsg_get_done_cmd(bd); 504 if (IS_ERR(bc)) 505 break; 506 507 tret = blk_complete_sgv4_hdr_rq(bc->rq, &bc->hdr, bc->bio, 508 bc->bidi_bio); 509 if (!ret) 510 ret = tret; 511 512 bsg_free_command(bc); 513 } while (1); 514 515 return ret; 516 } 517 518 static int 519 __bsg_read(char __user *buf, size_t count, struct bsg_device *bd, 520 const struct iovec *iov, ssize_t *bytes_read) 521 { 522 struct bsg_command *bc; 523 int nr_commands, ret; 524 525 if (count % sizeof(struct sg_io_v4)) 526 return -EINVAL; 527 528 ret = 0; 529 nr_commands = count / sizeof(struct sg_io_v4); 530 while (nr_commands) { 531 bc = bsg_get_done_cmd(bd); 532 if (IS_ERR(bc)) { 533 ret = PTR_ERR(bc); 534 break; 535 } 536 537 /* 538 * this is the only case where we need to copy data back 539 * after completing the request. so do that here, 540 * bsg_complete_work() cannot do that for us 541 */ 542 ret = blk_complete_sgv4_hdr_rq(bc->rq, &bc->hdr, bc->bio, 543 bc->bidi_bio); 544 545 if (copy_to_user(buf, &bc->hdr, sizeof(bc->hdr))) 546 ret = -EFAULT; 547 548 bsg_free_command(bc); 549 550 if (ret) 551 break; 552 553 buf += sizeof(struct sg_io_v4); 554 *bytes_read += sizeof(struct sg_io_v4); 555 nr_commands--; 556 } 557 558 return ret; 559 } 560 561 static inline void bsg_set_block(struct bsg_device *bd, struct file *file) 562 { 563 if (file->f_flags & O_NONBLOCK) 564 clear_bit(BSG_F_BLOCK, &bd->flags); 565 else 566 set_bit(BSG_F_BLOCK, &bd->flags); 567 } 568 569 /* 570 * Check if the error is a "real" error that we should return. 571 */ 572 static inline int err_block_err(int ret) 573 { 574 if (ret && ret != -ENOSPC && ret != -ENODATA && ret != -EAGAIN) 575 return 1; 576 577 return 0; 578 } 579 580 static ssize_t 581 bsg_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) 582 { 583 struct bsg_device *bd = file->private_data; 584 int ret; 585 ssize_t bytes_read; 586 587 dprintk("%s: read %Zd bytes\n", bd->name, count); 588 589 bsg_set_block(bd, file); 590 591 bytes_read = 0; 592 ret = __bsg_read(buf, count, bd, NULL, &bytes_read); 593 *ppos = bytes_read; 594 595 if (!bytes_read || (bytes_read && err_block_err(ret))) 596 bytes_read = ret; 597 598 return bytes_read; 599 } 600 601 static int __bsg_write(struct bsg_device *bd, const char __user *buf, 602 size_t count, ssize_t *bytes_written, int has_write_perm) 603 { 604 struct bsg_command *bc; 605 struct request *rq; 606 int ret, nr_commands; 607 608 if (count % sizeof(struct sg_io_v4)) 609 return -EINVAL; 610 611 nr_commands = count / sizeof(struct sg_io_v4); 612 rq = NULL; 613 bc = NULL; 614 ret = 0; 615 while (nr_commands) { 616 struct request_queue *q = bd->queue; 617 618 bc = bsg_alloc_command(bd); 619 if (IS_ERR(bc)) { 620 ret = PTR_ERR(bc); 621 bc = NULL; 622 break; 623 } 624 625 if (copy_from_user(&bc->hdr, buf, sizeof(bc->hdr))) { 626 ret = -EFAULT; 627 break; 628 } 629 630 /* 631 * get a request, fill in the blanks, and add to request queue 632 */ 633 rq = bsg_map_hdr(bd, &bc->hdr, has_write_perm); 634 if (IS_ERR(rq)) { 635 ret = PTR_ERR(rq); 636 rq = NULL; 637 break; 638 } 639 640 bsg_add_command(bd, q, bc, rq); 641 bc = NULL; 642 rq = NULL; 643 nr_commands--; 644 buf += sizeof(struct sg_io_v4); 645 *bytes_written += sizeof(struct sg_io_v4); 646 } 647 648 if (bc) 649 bsg_free_command(bc); 650 651 return ret; 652 } 653 654 static ssize_t 655 bsg_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) 656 { 657 struct bsg_device *bd = file->private_data; 658 ssize_t bytes_written; 659 int ret; 660 661 dprintk("%s: write %Zd bytes\n", bd->name, count); 662 663 bsg_set_block(bd, file); 664 665 bytes_written = 0; 666 ret = __bsg_write(bd, buf, count, &bytes_written, 667 file->f_mode & FMODE_WRITE); 668 669 *ppos = bytes_written; 670 671 /* 672 * return bytes written on non-fatal errors 673 */ 674 if (!bytes_written || (bytes_written && err_block_err(ret))) 675 bytes_written = ret; 676 677 dprintk("%s: returning %Zd\n", bd->name, bytes_written); 678 return bytes_written; 679 } 680 681 static struct bsg_device *bsg_alloc_device(void) 682 { 683 struct bsg_device *bd; 684 685 bd = kzalloc(sizeof(struct bsg_device), GFP_KERNEL); 686 if (unlikely(!bd)) 687 return NULL; 688 689 spin_lock_init(&bd->lock); 690 691 bd->max_queue = BSG_DEFAULT_CMDS; 692 693 INIT_LIST_HEAD(&bd->busy_list); 694 INIT_LIST_HEAD(&bd->done_list); 695 INIT_HLIST_NODE(&bd->dev_list); 696 697 init_waitqueue_head(&bd->wq_free); 698 init_waitqueue_head(&bd->wq_done); 699 return bd; 700 } 701 702 static void bsg_kref_release_function(struct kref *kref) 703 { 704 struct bsg_class_device *bcd = 705 container_of(kref, struct bsg_class_device, ref); 706 struct device *parent = bcd->parent; 707 708 if (bcd->release) 709 bcd->release(bcd->parent); 710 711 put_device(parent); 712 } 713 714 static int bsg_put_device(struct bsg_device *bd) 715 { 716 int ret = 0, do_free; 717 struct request_queue *q = bd->queue; 718 719 mutex_lock(&bsg_mutex); 720 721 do_free = atomic_dec_and_test(&bd->ref_count); 722 if (!do_free) { 723 mutex_unlock(&bsg_mutex); 724 goto out; 725 } 726 727 hlist_del(&bd->dev_list); 728 mutex_unlock(&bsg_mutex); 729 730 dprintk("%s: tearing down\n", bd->name); 731 732 /* 733 * close can always block 734 */ 735 set_bit(BSG_F_BLOCK, &bd->flags); 736 737 /* 738 * correct error detection baddies here again. it's the responsibility 739 * of the app to properly reap commands before close() if it wants 740 * fool-proof error detection 741 */ 742 ret = bsg_complete_all_commands(bd); 743 744 kfree(bd); 745 out: 746 kref_put(&q->bsg_dev.ref, bsg_kref_release_function); 747 if (do_free) 748 blk_put_queue(q); 749 return ret; 750 } 751 752 static struct bsg_device *bsg_add_device(struct inode *inode, 753 struct request_queue *rq, 754 struct file *file) 755 { 756 struct bsg_device *bd; 757 int ret; 758 #ifdef BSG_DEBUG 759 unsigned char buf[32]; 760 #endif 761 ret = blk_get_queue(rq); 762 if (ret) 763 return ERR_PTR(-ENXIO); 764 765 bd = bsg_alloc_device(); 766 if (!bd) { 767 blk_put_queue(rq); 768 return ERR_PTR(-ENOMEM); 769 } 770 771 bd->queue = rq; 772 773 bsg_set_block(bd, file); 774 775 atomic_set(&bd->ref_count, 1); 776 mutex_lock(&bsg_mutex); 777 hlist_add_head(&bd->dev_list, bsg_dev_idx_hash(iminor(inode))); 778 779 strncpy(bd->name, rq->bsg_dev.class_dev->bus_id, sizeof(bd->name) - 1); 780 dprintk("bound to <%s>, max queue %d\n", 781 format_dev_t(buf, inode->i_rdev), bd->max_queue); 782 783 mutex_unlock(&bsg_mutex); 784 return bd; 785 } 786 787 static struct bsg_device *__bsg_get_device(int minor, struct request_queue *q) 788 { 789 struct bsg_device *bd; 790 struct hlist_node *entry; 791 792 mutex_lock(&bsg_mutex); 793 794 hlist_for_each_entry(bd, entry, bsg_dev_idx_hash(minor), dev_list) { 795 if (bd->queue == q) { 796 atomic_inc(&bd->ref_count); 797 goto found; 798 } 799 } 800 bd = NULL; 801 found: 802 mutex_unlock(&bsg_mutex); 803 return bd; 804 } 805 806 static struct bsg_device *bsg_get_device(struct inode *inode, struct file *file) 807 { 808 struct bsg_device *bd; 809 struct bsg_class_device *bcd; 810 811 /* 812 * find the class device 813 */ 814 mutex_lock(&bsg_mutex); 815 bcd = idr_find(&bsg_minor_idr, iminor(inode)); 816 if (bcd) 817 kref_get(&bcd->ref); 818 mutex_unlock(&bsg_mutex); 819 820 if (!bcd) 821 return ERR_PTR(-ENODEV); 822 823 bd = __bsg_get_device(iminor(inode), bcd->queue); 824 if (bd) 825 return bd; 826 827 bd = bsg_add_device(inode, bcd->queue, file); 828 if (IS_ERR(bd)) 829 kref_put(&bcd->ref, bsg_kref_release_function); 830 831 return bd; 832 } 833 834 static int bsg_open(struct inode *inode, struct file *file) 835 { 836 struct bsg_device *bd; 837 838 lock_kernel(); 839 bd = bsg_get_device(inode, file); 840 unlock_kernel(); 841 842 if (IS_ERR(bd)) 843 return PTR_ERR(bd); 844 845 file->private_data = bd; 846 return 0; 847 } 848 849 static int bsg_release(struct inode *inode, struct file *file) 850 { 851 struct bsg_device *bd = file->private_data; 852 853 file->private_data = NULL; 854 return bsg_put_device(bd); 855 } 856 857 static unsigned int bsg_poll(struct file *file, poll_table *wait) 858 { 859 struct bsg_device *bd = file->private_data; 860 unsigned int mask = 0; 861 862 poll_wait(file, &bd->wq_done, wait); 863 poll_wait(file, &bd->wq_free, wait); 864 865 spin_lock_irq(&bd->lock); 866 if (!list_empty(&bd->done_list)) 867 mask |= POLLIN | POLLRDNORM; 868 if (bd->queued_cmds >= bd->max_queue) 869 mask |= POLLOUT; 870 spin_unlock_irq(&bd->lock); 871 872 return mask; 873 } 874 875 static long bsg_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 876 { 877 struct bsg_device *bd = file->private_data; 878 int __user *uarg = (int __user *) arg; 879 int ret; 880 881 switch (cmd) { 882 /* 883 * our own ioctls 884 */ 885 case SG_GET_COMMAND_Q: 886 return put_user(bd->max_queue, uarg); 887 case SG_SET_COMMAND_Q: { 888 int queue; 889 890 if (get_user(queue, uarg)) 891 return -EFAULT; 892 if (queue < 1) 893 return -EINVAL; 894 895 spin_lock_irq(&bd->lock); 896 bd->max_queue = queue; 897 spin_unlock_irq(&bd->lock); 898 return 0; 899 } 900 901 /* 902 * SCSI/sg ioctls 903 */ 904 case SG_GET_VERSION_NUM: 905 case SCSI_IOCTL_GET_IDLUN: 906 case SCSI_IOCTL_GET_BUS_NUMBER: 907 case SG_SET_TIMEOUT: 908 case SG_GET_TIMEOUT: 909 case SG_GET_RESERVED_SIZE: 910 case SG_SET_RESERVED_SIZE: 911 case SG_EMULATED_HOST: 912 case SCSI_IOCTL_SEND_COMMAND: { 913 void __user *uarg = (void __user *) arg; 914 return scsi_cmd_ioctl(file, bd->queue, NULL, cmd, uarg); 915 } 916 case SG_IO: { 917 struct request *rq; 918 struct bio *bio, *bidi_bio = NULL; 919 struct sg_io_v4 hdr; 920 921 if (copy_from_user(&hdr, uarg, sizeof(hdr))) 922 return -EFAULT; 923 924 rq = bsg_map_hdr(bd, &hdr, file->f_mode & FMODE_WRITE); 925 if (IS_ERR(rq)) 926 return PTR_ERR(rq); 927 928 bio = rq->bio; 929 if (rq->next_rq) 930 bidi_bio = rq->next_rq->bio; 931 blk_execute_rq(bd->queue, NULL, rq, 0); 932 ret = blk_complete_sgv4_hdr_rq(rq, &hdr, bio, bidi_bio); 933 934 if (copy_to_user(uarg, &hdr, sizeof(hdr))) 935 return -EFAULT; 936 937 return ret; 938 } 939 /* 940 * block device ioctls 941 */ 942 default: 943 #if 0 944 return ioctl_by_bdev(bd->bdev, cmd, arg); 945 #else 946 return -ENOTTY; 947 #endif 948 } 949 } 950 951 static const struct file_operations bsg_fops = { 952 .read = bsg_read, 953 .write = bsg_write, 954 .poll = bsg_poll, 955 .open = bsg_open, 956 .release = bsg_release, 957 .unlocked_ioctl = bsg_ioctl, 958 .owner = THIS_MODULE, 959 }; 960 961 void bsg_unregister_queue(struct request_queue *q) 962 { 963 struct bsg_class_device *bcd = &q->bsg_dev; 964 965 if (!bcd->class_dev) 966 return; 967 968 mutex_lock(&bsg_mutex); 969 idr_remove(&bsg_minor_idr, bcd->minor); 970 sysfs_remove_link(&q->kobj, "bsg"); 971 device_unregister(bcd->class_dev); 972 bcd->class_dev = NULL; 973 kref_put(&bcd->ref, bsg_kref_release_function); 974 mutex_unlock(&bsg_mutex); 975 } 976 EXPORT_SYMBOL_GPL(bsg_unregister_queue); 977 978 int bsg_register_queue(struct request_queue *q, struct device *parent, 979 const char *name, void (*release)(struct device *)) 980 { 981 struct bsg_class_device *bcd; 982 dev_t dev; 983 int ret, minor; 984 struct device *class_dev = NULL; 985 const char *devname; 986 987 if (name) 988 devname = name; 989 else 990 devname = parent->bus_id; 991 992 /* 993 * we need a proper transport to send commands, not a stacked device 994 */ 995 if (!q->request_fn) 996 return 0; 997 998 bcd = &q->bsg_dev; 999 memset(bcd, 0, sizeof(*bcd)); 1000 1001 mutex_lock(&bsg_mutex); 1002 1003 ret = idr_pre_get(&bsg_minor_idr, GFP_KERNEL); 1004 if (!ret) { 1005 ret = -ENOMEM; 1006 goto unlock; 1007 } 1008 1009 ret = idr_get_new(&bsg_minor_idr, bcd, &minor); 1010 if (ret < 0) 1011 goto unlock; 1012 1013 if (minor >= BSG_MAX_DEVS) { 1014 printk(KERN_ERR "bsg: too many bsg devices\n"); 1015 ret = -EINVAL; 1016 goto remove_idr; 1017 } 1018 1019 bcd->minor = minor; 1020 bcd->queue = q; 1021 bcd->parent = get_device(parent); 1022 bcd->release = release; 1023 kref_init(&bcd->ref); 1024 dev = MKDEV(bsg_major, bcd->minor); 1025 class_dev = device_create_drvdata(bsg_class, parent, dev, NULL, 1026 "%s", devname); 1027 if (IS_ERR(class_dev)) { 1028 ret = PTR_ERR(class_dev); 1029 goto put_dev; 1030 } 1031 bcd->class_dev = class_dev; 1032 1033 if (q->kobj.sd) { 1034 ret = sysfs_create_link(&q->kobj, &bcd->class_dev->kobj, "bsg"); 1035 if (ret) 1036 goto unregister_class_dev; 1037 } 1038 1039 mutex_unlock(&bsg_mutex); 1040 return 0; 1041 1042 unregister_class_dev: 1043 device_unregister(class_dev); 1044 put_dev: 1045 put_device(parent); 1046 remove_idr: 1047 idr_remove(&bsg_minor_idr, minor); 1048 unlock: 1049 mutex_unlock(&bsg_mutex); 1050 return ret; 1051 } 1052 EXPORT_SYMBOL_GPL(bsg_register_queue); 1053 1054 static struct cdev bsg_cdev; 1055 1056 static int __init bsg_init(void) 1057 { 1058 int ret, i; 1059 dev_t devid; 1060 1061 bsg_cmd_cachep = kmem_cache_create("bsg_cmd", 1062 sizeof(struct bsg_command), 0, 0, NULL); 1063 if (!bsg_cmd_cachep) { 1064 printk(KERN_ERR "bsg: failed creating slab cache\n"); 1065 return -ENOMEM; 1066 } 1067 1068 for (i = 0; i < BSG_LIST_ARRAY_SIZE; i++) 1069 INIT_HLIST_HEAD(&bsg_device_list[i]); 1070 1071 bsg_class = class_create(THIS_MODULE, "bsg"); 1072 if (IS_ERR(bsg_class)) { 1073 ret = PTR_ERR(bsg_class); 1074 goto destroy_kmemcache; 1075 } 1076 1077 ret = alloc_chrdev_region(&devid, 0, BSG_MAX_DEVS, "bsg"); 1078 if (ret) 1079 goto destroy_bsg_class; 1080 1081 bsg_major = MAJOR(devid); 1082 1083 cdev_init(&bsg_cdev, &bsg_fops); 1084 ret = cdev_add(&bsg_cdev, MKDEV(bsg_major, 0), BSG_MAX_DEVS); 1085 if (ret) 1086 goto unregister_chrdev; 1087 1088 printk(KERN_INFO BSG_DESCRIPTION " version " BSG_VERSION 1089 " loaded (major %d)\n", bsg_major); 1090 return 0; 1091 unregister_chrdev: 1092 unregister_chrdev_region(MKDEV(bsg_major, 0), BSG_MAX_DEVS); 1093 destroy_bsg_class: 1094 class_destroy(bsg_class); 1095 destroy_kmemcache: 1096 kmem_cache_destroy(bsg_cmd_cachep); 1097 return ret; 1098 } 1099 1100 MODULE_AUTHOR("Jens Axboe"); 1101 MODULE_DESCRIPTION(BSG_DESCRIPTION); 1102 MODULE_LICENSE("GPL"); 1103 1104 device_initcall(bsg_init); 1105