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/jiffies.h> 19 #include <linux/percpu.h> 20 #include <linux/uio.h> 21 #include <linux/idr.h> 22 #include <linux/bsg.h> 23 #include <linux/smp_lock.h> 24 #include <linux/slab.h> 25 26 #include <scsi/scsi.h> 27 #include <scsi/scsi_ioctl.h> 28 #include <scsi/scsi_cmnd.h> 29 #include <scsi/scsi_device.h> 30 #include <scsi/scsi_driver.h> 31 #include <scsi/sg.h> 32 33 #define BSG_DESCRIPTION "Block layer SCSI generic (bsg) driver" 34 #define BSG_VERSION "0.4" 35 36 struct bsg_device { 37 struct request_queue *queue; 38 spinlock_t lock; 39 struct list_head busy_list; 40 struct list_head done_list; 41 struct hlist_node dev_list; 42 atomic_t ref_count; 43 int queued_cmds; 44 int done_cmds; 45 wait_queue_head_t wq_done; 46 wait_queue_head_t wq_free; 47 char name[20]; 48 int max_queue; 49 unsigned long flags; 50 }; 51 52 enum { 53 BSG_F_BLOCK = 1, 54 }; 55 56 #define BSG_DEFAULT_CMDS 64 57 #define BSG_MAX_DEVS 32768 58 59 #undef BSG_DEBUG 60 61 #ifdef BSG_DEBUG 62 #define dprintk(fmt, args...) printk(KERN_ERR "%s: " fmt, __func__, ##args) 63 #else 64 #define dprintk(fmt, args...) 65 #endif 66 67 static DEFINE_MUTEX(bsg_mutex); 68 static DEFINE_IDR(bsg_minor_idr); 69 70 #define BSG_LIST_ARRAY_SIZE 8 71 static struct hlist_head bsg_device_list[BSG_LIST_ARRAY_SIZE]; 72 73 static struct class *bsg_class; 74 static int bsg_major; 75 76 static struct kmem_cache *bsg_cmd_cachep; 77 78 /* 79 * our internal command type 80 */ 81 struct bsg_command { 82 struct bsg_device *bd; 83 struct list_head list; 84 struct request *rq; 85 struct bio *bio; 86 struct bio *bidi_bio; 87 int err; 88 struct sg_io_v4 hdr; 89 char sense[SCSI_SENSE_BUFFERSIZE]; 90 }; 91 92 static void bsg_free_command(struct bsg_command *bc) 93 { 94 struct bsg_device *bd = bc->bd; 95 unsigned long flags; 96 97 kmem_cache_free(bsg_cmd_cachep, bc); 98 99 spin_lock_irqsave(&bd->lock, flags); 100 bd->queued_cmds--; 101 spin_unlock_irqrestore(&bd->lock, flags); 102 103 wake_up(&bd->wq_free); 104 } 105 106 static struct bsg_command *bsg_alloc_command(struct bsg_device *bd) 107 { 108 struct bsg_command *bc = ERR_PTR(-EINVAL); 109 110 spin_lock_irq(&bd->lock); 111 112 if (bd->queued_cmds >= bd->max_queue) 113 goto out; 114 115 bd->queued_cmds++; 116 spin_unlock_irq(&bd->lock); 117 118 bc = kmem_cache_zalloc(bsg_cmd_cachep, GFP_KERNEL); 119 if (unlikely(!bc)) { 120 spin_lock_irq(&bd->lock); 121 bd->queued_cmds--; 122 bc = ERR_PTR(-ENOMEM); 123 goto out; 124 } 125 126 bc->bd = bd; 127 INIT_LIST_HEAD(&bc->list); 128 dprintk("%s: returning free cmd %p\n", bd->name, bc); 129 return bc; 130 out: 131 spin_unlock_irq(&bd->lock); 132 return bc; 133 } 134 135 static inline struct hlist_head *bsg_dev_idx_hash(int index) 136 { 137 return &bsg_device_list[index & (BSG_LIST_ARRAY_SIZE - 1)]; 138 } 139 140 static int bsg_io_schedule(struct bsg_device *bd) 141 { 142 DEFINE_WAIT(wait); 143 int ret = 0; 144 145 spin_lock_irq(&bd->lock); 146 147 BUG_ON(bd->done_cmds > bd->queued_cmds); 148 149 /* 150 * -ENOSPC or -ENODATA? I'm going for -ENODATA, meaning "I have no 151 * work to do", even though we return -ENOSPC after this same test 152 * during bsg_write() -- there, it means our buffer can't have more 153 * bsg_commands added to it, thus has no space left. 154 */ 155 if (bd->done_cmds == bd->queued_cmds) { 156 ret = -ENODATA; 157 goto unlock; 158 } 159 160 if (!test_bit(BSG_F_BLOCK, &bd->flags)) { 161 ret = -EAGAIN; 162 goto unlock; 163 } 164 165 prepare_to_wait(&bd->wq_done, &wait, TASK_UNINTERRUPTIBLE); 166 spin_unlock_irq(&bd->lock); 167 io_schedule(); 168 finish_wait(&bd->wq_done, &wait); 169 170 return ret; 171 unlock: 172 spin_unlock_irq(&bd->lock); 173 return ret; 174 } 175 176 static int blk_fill_sgv4_hdr_rq(struct request_queue *q, struct request *rq, 177 struct sg_io_v4 *hdr, struct bsg_device *bd, 178 fmode_t has_write_perm) 179 { 180 if (hdr->request_len > BLK_MAX_CDB) { 181 rq->cmd = kzalloc(hdr->request_len, GFP_KERNEL); 182 if (!rq->cmd) 183 return -ENOMEM; 184 } 185 186 if (copy_from_user(rq->cmd, (void *)(unsigned long)hdr->request, 187 hdr->request_len)) 188 return -EFAULT; 189 190 if (hdr->subprotocol == BSG_SUB_PROTOCOL_SCSI_CMD) { 191 if (blk_verify_command(rq->cmd, has_write_perm)) 192 return -EPERM; 193 } else if (!capable(CAP_SYS_RAWIO)) 194 return -EPERM; 195 196 /* 197 * fill in request structure 198 */ 199 rq->cmd_len = hdr->request_len; 200 rq->cmd_type = REQ_TYPE_BLOCK_PC; 201 202 rq->timeout = msecs_to_jiffies(hdr->timeout); 203 if (!rq->timeout) 204 rq->timeout = q->sg_timeout; 205 if (!rq->timeout) 206 rq->timeout = BLK_DEFAULT_SG_TIMEOUT; 207 if (rq->timeout < BLK_MIN_SG_TIMEOUT) 208 rq->timeout = BLK_MIN_SG_TIMEOUT; 209 210 return 0; 211 } 212 213 /* 214 * Check if sg_io_v4 from user is allowed and valid 215 */ 216 static int 217 bsg_validate_sgv4_hdr(struct request_queue *q, struct sg_io_v4 *hdr, int *rw) 218 { 219 int ret = 0; 220 221 if (hdr->guard != 'Q') 222 return -EINVAL; 223 224 switch (hdr->protocol) { 225 case BSG_PROTOCOL_SCSI: 226 switch (hdr->subprotocol) { 227 case BSG_SUB_PROTOCOL_SCSI_CMD: 228 case BSG_SUB_PROTOCOL_SCSI_TRANSPORT: 229 break; 230 default: 231 ret = -EINVAL; 232 } 233 break; 234 default: 235 ret = -EINVAL; 236 } 237 238 *rw = hdr->dout_xfer_len ? WRITE : READ; 239 return ret; 240 } 241 242 /* 243 * map sg_io_v4 to a request. 244 */ 245 static struct request * 246 bsg_map_hdr(struct bsg_device *bd, struct sg_io_v4 *hdr, fmode_t has_write_perm, 247 u8 *sense) 248 { 249 struct request_queue *q = bd->queue; 250 struct request *rq, *next_rq = NULL; 251 int ret, rw; 252 unsigned int dxfer_len; 253 void *dxferp = NULL; 254 255 dprintk("map hdr %llx/%u %llx/%u\n", (unsigned long long) hdr->dout_xferp, 256 hdr->dout_xfer_len, (unsigned long long) hdr->din_xferp, 257 hdr->din_xfer_len); 258 259 ret = bsg_validate_sgv4_hdr(q, hdr, &rw); 260 if (ret) 261 return ERR_PTR(ret); 262 263 /* 264 * map scatter-gather elements separately and string them to request 265 */ 266 rq = blk_get_request(q, rw, GFP_KERNEL); 267 if (!rq) 268 return ERR_PTR(-ENOMEM); 269 ret = blk_fill_sgv4_hdr_rq(q, rq, hdr, bd, has_write_perm); 270 if (ret) 271 goto out; 272 273 if (rw == WRITE && hdr->din_xfer_len) { 274 if (!test_bit(QUEUE_FLAG_BIDI, &q->queue_flags)) { 275 ret = -EOPNOTSUPP; 276 goto out; 277 } 278 279 next_rq = blk_get_request(q, READ, GFP_KERNEL); 280 if (!next_rq) { 281 ret = -ENOMEM; 282 goto out; 283 } 284 rq->next_rq = next_rq; 285 next_rq->cmd_type = rq->cmd_type; 286 287 dxferp = (void*)(unsigned long)hdr->din_xferp; 288 ret = blk_rq_map_user(q, next_rq, NULL, dxferp, 289 hdr->din_xfer_len, GFP_KERNEL); 290 if (ret) 291 goto out; 292 } 293 294 if (hdr->dout_xfer_len) { 295 dxfer_len = hdr->dout_xfer_len; 296 dxferp = (void*)(unsigned long)hdr->dout_xferp; 297 } else if (hdr->din_xfer_len) { 298 dxfer_len = hdr->din_xfer_len; 299 dxferp = (void*)(unsigned long)hdr->din_xferp; 300 } else 301 dxfer_len = 0; 302 303 if (dxfer_len) { 304 ret = blk_rq_map_user(q, rq, NULL, dxferp, dxfer_len, 305 GFP_KERNEL); 306 if (ret) 307 goto out; 308 } 309 310 rq->sense = sense; 311 rq->sense_len = 0; 312 313 return rq; 314 out: 315 if (rq->cmd != rq->__cmd) 316 kfree(rq->cmd); 317 blk_put_request(rq); 318 if (next_rq) { 319 blk_rq_unmap_user(next_rq->bio); 320 blk_put_request(next_rq); 321 } 322 return ERR_PTR(ret); 323 } 324 325 /* 326 * async completion call-back from the block layer, when scsi/ide/whatever 327 * calls end_that_request_last() on a request 328 */ 329 static void bsg_rq_end_io(struct request *rq, int uptodate) 330 { 331 struct bsg_command *bc = rq->end_io_data; 332 struct bsg_device *bd = bc->bd; 333 unsigned long flags; 334 335 dprintk("%s: finished rq %p bc %p, bio %p stat %d\n", 336 bd->name, rq, bc, bc->bio, uptodate); 337 338 bc->hdr.duration = jiffies_to_msecs(jiffies - bc->hdr.duration); 339 340 spin_lock_irqsave(&bd->lock, flags); 341 list_move_tail(&bc->list, &bd->done_list); 342 bd->done_cmds++; 343 spin_unlock_irqrestore(&bd->lock, flags); 344 345 wake_up(&bd->wq_done); 346 } 347 348 /* 349 * do final setup of a 'bc' and submit the matching 'rq' to the block 350 * layer for io 351 */ 352 static void bsg_add_command(struct bsg_device *bd, struct request_queue *q, 353 struct bsg_command *bc, struct request *rq) 354 { 355 int at_head = (0 == (bc->hdr.flags & BSG_FLAG_Q_AT_TAIL)); 356 357 /* 358 * add bc command to busy queue and submit rq for io 359 */ 360 bc->rq = rq; 361 bc->bio = rq->bio; 362 if (rq->next_rq) 363 bc->bidi_bio = rq->next_rq->bio; 364 bc->hdr.duration = jiffies; 365 spin_lock_irq(&bd->lock); 366 list_add_tail(&bc->list, &bd->busy_list); 367 spin_unlock_irq(&bd->lock); 368 369 dprintk("%s: queueing rq %p, bc %p\n", bd->name, rq, bc); 370 371 rq->end_io_data = bc; 372 blk_execute_rq_nowait(q, NULL, rq, at_head, bsg_rq_end_io); 373 } 374 375 static struct bsg_command *bsg_next_done_cmd(struct bsg_device *bd) 376 { 377 struct bsg_command *bc = NULL; 378 379 spin_lock_irq(&bd->lock); 380 if (bd->done_cmds) { 381 bc = list_first_entry(&bd->done_list, struct bsg_command, list); 382 list_del(&bc->list); 383 bd->done_cmds--; 384 } 385 spin_unlock_irq(&bd->lock); 386 387 return bc; 388 } 389 390 /* 391 * Get a finished command from the done list 392 */ 393 static struct bsg_command *bsg_get_done_cmd(struct bsg_device *bd) 394 { 395 struct bsg_command *bc; 396 int ret; 397 398 do { 399 bc = bsg_next_done_cmd(bd); 400 if (bc) 401 break; 402 403 if (!test_bit(BSG_F_BLOCK, &bd->flags)) { 404 bc = ERR_PTR(-EAGAIN); 405 break; 406 } 407 408 ret = wait_event_interruptible(bd->wq_done, bd->done_cmds); 409 if (ret) { 410 bc = ERR_PTR(-ERESTARTSYS); 411 break; 412 } 413 } while (1); 414 415 dprintk("%s: returning done %p\n", bd->name, bc); 416 417 return bc; 418 } 419 420 static int blk_complete_sgv4_hdr_rq(struct request *rq, struct sg_io_v4 *hdr, 421 struct bio *bio, struct bio *bidi_bio) 422 { 423 int ret = 0; 424 425 dprintk("rq %p bio %p 0x%x\n", rq, bio, rq->errors); 426 /* 427 * fill in all the output members 428 */ 429 hdr->device_status = rq->errors & 0xff; 430 hdr->transport_status = host_byte(rq->errors); 431 hdr->driver_status = driver_byte(rq->errors); 432 hdr->info = 0; 433 if (hdr->device_status || hdr->transport_status || hdr->driver_status) 434 hdr->info |= SG_INFO_CHECK; 435 hdr->response_len = 0; 436 437 if (rq->sense_len && hdr->response) { 438 int len = min_t(unsigned int, hdr->max_response_len, 439 rq->sense_len); 440 441 ret = copy_to_user((void*)(unsigned long)hdr->response, 442 rq->sense, len); 443 if (!ret) 444 hdr->response_len = len; 445 else 446 ret = -EFAULT; 447 } 448 449 if (rq->next_rq) { 450 hdr->dout_resid = rq->resid_len; 451 hdr->din_resid = rq->next_rq->resid_len; 452 blk_rq_unmap_user(bidi_bio); 453 blk_put_request(rq->next_rq); 454 } else if (rq_data_dir(rq) == READ) 455 hdr->din_resid = rq->resid_len; 456 else 457 hdr->dout_resid = rq->resid_len; 458 459 /* 460 * If the request generated a negative error number, return it 461 * (providing we aren't already returning an error); if it's 462 * just a protocol response (i.e. non negative), that gets 463 * processed above. 464 */ 465 if (!ret && rq->errors < 0) 466 ret = rq->errors; 467 468 blk_rq_unmap_user(bio); 469 if (rq->cmd != rq->__cmd) 470 kfree(rq->cmd); 471 blk_put_request(rq); 472 473 return ret; 474 } 475 476 static int bsg_complete_all_commands(struct bsg_device *bd) 477 { 478 struct bsg_command *bc; 479 int ret, tret; 480 481 dprintk("%s: entered\n", bd->name); 482 483 /* 484 * wait for all commands to complete 485 */ 486 ret = 0; 487 do { 488 ret = bsg_io_schedule(bd); 489 /* 490 * look for -ENODATA specifically -- we'll sometimes get 491 * -ERESTARTSYS when we've taken a signal, but we can't 492 * return until we're done freeing the queue, so ignore 493 * it. The signal will get handled when we're done freeing 494 * the bsg_device. 495 */ 496 } while (ret != -ENODATA); 497 498 /* 499 * discard done commands 500 */ 501 ret = 0; 502 do { 503 spin_lock_irq(&bd->lock); 504 if (!bd->queued_cmds) { 505 spin_unlock_irq(&bd->lock); 506 break; 507 } 508 spin_unlock_irq(&bd->lock); 509 510 bc = bsg_get_done_cmd(bd); 511 if (IS_ERR(bc)) 512 break; 513 514 tret = blk_complete_sgv4_hdr_rq(bc->rq, &bc->hdr, bc->bio, 515 bc->bidi_bio); 516 if (!ret) 517 ret = tret; 518 519 bsg_free_command(bc); 520 } while (1); 521 522 return ret; 523 } 524 525 static int 526 __bsg_read(char __user *buf, size_t count, struct bsg_device *bd, 527 const struct iovec *iov, ssize_t *bytes_read) 528 { 529 struct bsg_command *bc; 530 int nr_commands, ret; 531 532 if (count % sizeof(struct sg_io_v4)) 533 return -EINVAL; 534 535 ret = 0; 536 nr_commands = count / sizeof(struct sg_io_v4); 537 while (nr_commands) { 538 bc = bsg_get_done_cmd(bd); 539 if (IS_ERR(bc)) { 540 ret = PTR_ERR(bc); 541 break; 542 } 543 544 /* 545 * this is the only case where we need to copy data back 546 * after completing the request. so do that here, 547 * bsg_complete_work() cannot do that for us 548 */ 549 ret = blk_complete_sgv4_hdr_rq(bc->rq, &bc->hdr, bc->bio, 550 bc->bidi_bio); 551 552 if (copy_to_user(buf, &bc->hdr, sizeof(bc->hdr))) 553 ret = -EFAULT; 554 555 bsg_free_command(bc); 556 557 if (ret) 558 break; 559 560 buf += sizeof(struct sg_io_v4); 561 *bytes_read += sizeof(struct sg_io_v4); 562 nr_commands--; 563 } 564 565 return ret; 566 } 567 568 static inline void bsg_set_block(struct bsg_device *bd, struct file *file) 569 { 570 if (file->f_flags & O_NONBLOCK) 571 clear_bit(BSG_F_BLOCK, &bd->flags); 572 else 573 set_bit(BSG_F_BLOCK, &bd->flags); 574 } 575 576 /* 577 * Check if the error is a "real" error that we should return. 578 */ 579 static inline int err_block_err(int ret) 580 { 581 if (ret && ret != -ENOSPC && ret != -ENODATA && ret != -EAGAIN) 582 return 1; 583 584 return 0; 585 } 586 587 static ssize_t 588 bsg_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) 589 { 590 struct bsg_device *bd = file->private_data; 591 int ret; 592 ssize_t bytes_read; 593 594 dprintk("%s: read %Zd bytes\n", bd->name, count); 595 596 bsg_set_block(bd, file); 597 598 bytes_read = 0; 599 ret = __bsg_read(buf, count, bd, NULL, &bytes_read); 600 *ppos = bytes_read; 601 602 if (!bytes_read || (bytes_read && err_block_err(ret))) 603 bytes_read = ret; 604 605 return bytes_read; 606 } 607 608 static int __bsg_write(struct bsg_device *bd, const char __user *buf, 609 size_t count, ssize_t *bytes_written, 610 fmode_t has_write_perm) 611 { 612 struct bsg_command *bc; 613 struct request *rq; 614 int ret, nr_commands; 615 616 if (count % sizeof(struct sg_io_v4)) 617 return -EINVAL; 618 619 nr_commands = count / sizeof(struct sg_io_v4); 620 rq = NULL; 621 bc = NULL; 622 ret = 0; 623 while (nr_commands) { 624 struct request_queue *q = bd->queue; 625 626 bc = bsg_alloc_command(bd); 627 if (IS_ERR(bc)) { 628 ret = PTR_ERR(bc); 629 bc = NULL; 630 break; 631 } 632 633 if (copy_from_user(&bc->hdr, buf, sizeof(bc->hdr))) { 634 ret = -EFAULT; 635 break; 636 } 637 638 /* 639 * get a request, fill in the blanks, and add to request queue 640 */ 641 rq = bsg_map_hdr(bd, &bc->hdr, has_write_perm, bc->sense); 642 if (IS_ERR(rq)) { 643 ret = PTR_ERR(rq); 644 rq = NULL; 645 break; 646 } 647 648 bsg_add_command(bd, q, bc, rq); 649 bc = NULL; 650 rq = NULL; 651 nr_commands--; 652 buf += sizeof(struct sg_io_v4); 653 *bytes_written += sizeof(struct sg_io_v4); 654 } 655 656 if (bc) 657 bsg_free_command(bc); 658 659 return ret; 660 } 661 662 static ssize_t 663 bsg_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) 664 { 665 struct bsg_device *bd = file->private_data; 666 ssize_t bytes_written; 667 int ret; 668 669 dprintk("%s: write %Zd bytes\n", bd->name, count); 670 671 bsg_set_block(bd, file); 672 673 bytes_written = 0; 674 ret = __bsg_write(bd, buf, count, &bytes_written, 675 file->f_mode & FMODE_WRITE); 676 677 *ppos = bytes_written; 678 679 /* 680 * return bytes written on non-fatal errors 681 */ 682 if (!bytes_written || (bytes_written && err_block_err(ret))) 683 bytes_written = ret; 684 685 dprintk("%s: returning %Zd\n", bd->name, bytes_written); 686 return bytes_written; 687 } 688 689 static struct bsg_device *bsg_alloc_device(void) 690 { 691 struct bsg_device *bd; 692 693 bd = kzalloc(sizeof(struct bsg_device), GFP_KERNEL); 694 if (unlikely(!bd)) 695 return NULL; 696 697 spin_lock_init(&bd->lock); 698 699 bd->max_queue = BSG_DEFAULT_CMDS; 700 701 INIT_LIST_HEAD(&bd->busy_list); 702 INIT_LIST_HEAD(&bd->done_list); 703 INIT_HLIST_NODE(&bd->dev_list); 704 705 init_waitqueue_head(&bd->wq_free); 706 init_waitqueue_head(&bd->wq_done); 707 return bd; 708 } 709 710 static void bsg_kref_release_function(struct kref *kref) 711 { 712 struct bsg_class_device *bcd = 713 container_of(kref, struct bsg_class_device, ref); 714 struct device *parent = bcd->parent; 715 716 if (bcd->release) 717 bcd->release(bcd->parent); 718 719 put_device(parent); 720 } 721 722 static int bsg_put_device(struct bsg_device *bd) 723 { 724 int ret = 0, do_free; 725 struct request_queue *q = bd->queue; 726 727 mutex_lock(&bsg_mutex); 728 729 do_free = atomic_dec_and_test(&bd->ref_count); 730 if (!do_free) { 731 mutex_unlock(&bsg_mutex); 732 goto out; 733 } 734 735 hlist_del(&bd->dev_list); 736 mutex_unlock(&bsg_mutex); 737 738 dprintk("%s: tearing down\n", bd->name); 739 740 /* 741 * close can always block 742 */ 743 set_bit(BSG_F_BLOCK, &bd->flags); 744 745 /* 746 * correct error detection baddies here again. it's the responsibility 747 * of the app to properly reap commands before close() if it wants 748 * fool-proof error detection 749 */ 750 ret = bsg_complete_all_commands(bd); 751 752 kfree(bd); 753 out: 754 kref_put(&q->bsg_dev.ref, bsg_kref_release_function); 755 if (do_free) 756 blk_put_queue(q); 757 return ret; 758 } 759 760 static struct bsg_device *bsg_add_device(struct inode *inode, 761 struct request_queue *rq, 762 struct file *file) 763 { 764 struct bsg_device *bd; 765 int ret; 766 #ifdef BSG_DEBUG 767 unsigned char buf[32]; 768 #endif 769 ret = blk_get_queue(rq); 770 if (ret) 771 return ERR_PTR(-ENXIO); 772 773 bd = bsg_alloc_device(); 774 if (!bd) { 775 blk_put_queue(rq); 776 return ERR_PTR(-ENOMEM); 777 } 778 779 bd->queue = rq; 780 781 bsg_set_block(bd, file); 782 783 atomic_set(&bd->ref_count, 1); 784 mutex_lock(&bsg_mutex); 785 hlist_add_head(&bd->dev_list, bsg_dev_idx_hash(iminor(inode))); 786 787 strncpy(bd->name, dev_name(rq->bsg_dev.class_dev), sizeof(bd->name) - 1); 788 dprintk("bound to <%s>, max queue %d\n", 789 format_dev_t(buf, inode->i_rdev), bd->max_queue); 790 791 mutex_unlock(&bsg_mutex); 792 return bd; 793 } 794 795 static struct bsg_device *__bsg_get_device(int minor, struct request_queue *q) 796 { 797 struct bsg_device *bd; 798 struct hlist_node *entry; 799 800 mutex_lock(&bsg_mutex); 801 802 hlist_for_each_entry(bd, entry, bsg_dev_idx_hash(minor), dev_list) { 803 if (bd->queue == q) { 804 atomic_inc(&bd->ref_count); 805 goto found; 806 } 807 } 808 bd = NULL; 809 found: 810 mutex_unlock(&bsg_mutex); 811 return bd; 812 } 813 814 static struct bsg_device *bsg_get_device(struct inode *inode, struct file *file) 815 { 816 struct bsg_device *bd; 817 struct bsg_class_device *bcd; 818 819 /* 820 * find the class device 821 */ 822 mutex_lock(&bsg_mutex); 823 bcd = idr_find(&bsg_minor_idr, iminor(inode)); 824 if (bcd) 825 kref_get(&bcd->ref); 826 mutex_unlock(&bsg_mutex); 827 828 if (!bcd) 829 return ERR_PTR(-ENODEV); 830 831 bd = __bsg_get_device(iminor(inode), bcd->queue); 832 if (bd) 833 return bd; 834 835 bd = bsg_add_device(inode, bcd->queue, file); 836 if (IS_ERR(bd)) 837 kref_put(&bcd->ref, bsg_kref_release_function); 838 839 return bd; 840 } 841 842 static int bsg_open(struct inode *inode, struct file *file) 843 { 844 struct bsg_device *bd; 845 846 lock_kernel(); 847 bd = bsg_get_device(inode, file); 848 unlock_kernel(); 849 850 if (IS_ERR(bd)) 851 return PTR_ERR(bd); 852 853 file->private_data = bd; 854 return 0; 855 } 856 857 static int bsg_release(struct inode *inode, struct file *file) 858 { 859 struct bsg_device *bd = file->private_data; 860 861 file->private_data = NULL; 862 return bsg_put_device(bd); 863 } 864 865 static unsigned int bsg_poll(struct file *file, poll_table *wait) 866 { 867 struct bsg_device *bd = file->private_data; 868 unsigned int mask = 0; 869 870 poll_wait(file, &bd->wq_done, wait); 871 poll_wait(file, &bd->wq_free, wait); 872 873 spin_lock_irq(&bd->lock); 874 if (!list_empty(&bd->done_list)) 875 mask |= POLLIN | POLLRDNORM; 876 if (bd->queued_cmds >= bd->max_queue) 877 mask |= POLLOUT; 878 spin_unlock_irq(&bd->lock); 879 880 return mask; 881 } 882 883 static long bsg_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 884 { 885 struct bsg_device *bd = file->private_data; 886 int __user *uarg = (int __user *) arg; 887 int ret; 888 889 switch (cmd) { 890 /* 891 * our own ioctls 892 */ 893 case SG_GET_COMMAND_Q: 894 return put_user(bd->max_queue, uarg); 895 case SG_SET_COMMAND_Q: { 896 int queue; 897 898 if (get_user(queue, uarg)) 899 return -EFAULT; 900 if (queue < 1) 901 return -EINVAL; 902 903 spin_lock_irq(&bd->lock); 904 bd->max_queue = queue; 905 spin_unlock_irq(&bd->lock); 906 return 0; 907 } 908 909 /* 910 * SCSI/sg ioctls 911 */ 912 case SG_GET_VERSION_NUM: 913 case SCSI_IOCTL_GET_IDLUN: 914 case SCSI_IOCTL_GET_BUS_NUMBER: 915 case SG_SET_TIMEOUT: 916 case SG_GET_TIMEOUT: 917 case SG_GET_RESERVED_SIZE: 918 case SG_SET_RESERVED_SIZE: 919 case SG_EMULATED_HOST: 920 case SCSI_IOCTL_SEND_COMMAND: { 921 void __user *uarg = (void __user *) arg; 922 return scsi_cmd_ioctl(bd->queue, NULL, file->f_mode, cmd, uarg); 923 } 924 case SG_IO: { 925 struct request *rq; 926 struct bio *bio, *bidi_bio = NULL; 927 struct sg_io_v4 hdr; 928 int at_head; 929 u8 sense[SCSI_SENSE_BUFFERSIZE]; 930 931 if (copy_from_user(&hdr, uarg, sizeof(hdr))) 932 return -EFAULT; 933 934 rq = bsg_map_hdr(bd, &hdr, file->f_mode & FMODE_WRITE, sense); 935 if (IS_ERR(rq)) 936 return PTR_ERR(rq); 937 938 bio = rq->bio; 939 if (rq->next_rq) 940 bidi_bio = rq->next_rq->bio; 941 942 at_head = (0 == (hdr.flags & BSG_FLAG_Q_AT_TAIL)); 943 blk_execute_rq(bd->queue, NULL, rq, at_head); 944 ret = blk_complete_sgv4_hdr_rq(rq, &hdr, bio, bidi_bio); 945 946 if (copy_to_user(uarg, &hdr, sizeof(hdr))) 947 return -EFAULT; 948 949 return ret; 950 } 951 /* 952 * block device ioctls 953 */ 954 default: 955 #if 0 956 return ioctl_by_bdev(bd->bdev, cmd, arg); 957 #else 958 return -ENOTTY; 959 #endif 960 } 961 } 962 963 static const struct file_operations bsg_fops = { 964 .read = bsg_read, 965 .write = bsg_write, 966 .poll = bsg_poll, 967 .open = bsg_open, 968 .release = bsg_release, 969 .unlocked_ioctl = bsg_ioctl, 970 .owner = THIS_MODULE, 971 }; 972 973 void bsg_unregister_queue(struct request_queue *q) 974 { 975 struct bsg_class_device *bcd = &q->bsg_dev; 976 977 if (!bcd->class_dev) 978 return; 979 980 mutex_lock(&bsg_mutex); 981 idr_remove(&bsg_minor_idr, bcd->minor); 982 sysfs_remove_link(&q->kobj, "bsg"); 983 device_unregister(bcd->class_dev); 984 bcd->class_dev = NULL; 985 kref_put(&bcd->ref, bsg_kref_release_function); 986 mutex_unlock(&bsg_mutex); 987 } 988 EXPORT_SYMBOL_GPL(bsg_unregister_queue); 989 990 int bsg_register_queue(struct request_queue *q, struct device *parent, 991 const char *name, void (*release)(struct device *)) 992 { 993 struct bsg_class_device *bcd; 994 dev_t dev; 995 int ret, minor; 996 struct device *class_dev = NULL; 997 const char *devname; 998 999 if (name) 1000 devname = name; 1001 else 1002 devname = dev_name(parent); 1003 1004 /* 1005 * we need a proper transport to send commands, not a stacked device 1006 */ 1007 if (!q->request_fn) 1008 return 0; 1009 1010 bcd = &q->bsg_dev; 1011 memset(bcd, 0, sizeof(*bcd)); 1012 1013 mutex_lock(&bsg_mutex); 1014 1015 ret = idr_pre_get(&bsg_minor_idr, GFP_KERNEL); 1016 if (!ret) { 1017 ret = -ENOMEM; 1018 goto unlock; 1019 } 1020 1021 ret = idr_get_new(&bsg_minor_idr, bcd, &minor); 1022 if (ret < 0) 1023 goto unlock; 1024 1025 if (minor >= BSG_MAX_DEVS) { 1026 printk(KERN_ERR "bsg: too many bsg devices\n"); 1027 ret = -EINVAL; 1028 goto remove_idr; 1029 } 1030 1031 bcd->minor = minor; 1032 bcd->queue = q; 1033 bcd->parent = get_device(parent); 1034 bcd->release = release; 1035 kref_init(&bcd->ref); 1036 dev = MKDEV(bsg_major, bcd->minor); 1037 class_dev = device_create(bsg_class, parent, dev, NULL, "%s", devname); 1038 if (IS_ERR(class_dev)) { 1039 ret = PTR_ERR(class_dev); 1040 goto put_dev; 1041 } 1042 bcd->class_dev = class_dev; 1043 1044 if (q->kobj.sd) { 1045 ret = sysfs_create_link(&q->kobj, &bcd->class_dev->kobj, "bsg"); 1046 if (ret) 1047 goto unregister_class_dev; 1048 } 1049 1050 mutex_unlock(&bsg_mutex); 1051 return 0; 1052 1053 unregister_class_dev: 1054 device_unregister(class_dev); 1055 put_dev: 1056 put_device(parent); 1057 remove_idr: 1058 idr_remove(&bsg_minor_idr, minor); 1059 unlock: 1060 mutex_unlock(&bsg_mutex); 1061 return ret; 1062 } 1063 EXPORT_SYMBOL_GPL(bsg_register_queue); 1064 1065 static struct cdev bsg_cdev; 1066 1067 static char *bsg_devnode(struct device *dev, mode_t *mode) 1068 { 1069 return kasprintf(GFP_KERNEL, "bsg/%s", dev_name(dev)); 1070 } 1071 1072 static int __init bsg_init(void) 1073 { 1074 int ret, i; 1075 dev_t devid; 1076 1077 bsg_cmd_cachep = kmem_cache_create("bsg_cmd", 1078 sizeof(struct bsg_command), 0, 0, NULL); 1079 if (!bsg_cmd_cachep) { 1080 printk(KERN_ERR "bsg: failed creating slab cache\n"); 1081 return -ENOMEM; 1082 } 1083 1084 for (i = 0; i < BSG_LIST_ARRAY_SIZE; i++) 1085 INIT_HLIST_HEAD(&bsg_device_list[i]); 1086 1087 bsg_class = class_create(THIS_MODULE, "bsg"); 1088 if (IS_ERR(bsg_class)) { 1089 ret = PTR_ERR(bsg_class); 1090 goto destroy_kmemcache; 1091 } 1092 bsg_class->devnode = bsg_devnode; 1093 1094 ret = alloc_chrdev_region(&devid, 0, BSG_MAX_DEVS, "bsg"); 1095 if (ret) 1096 goto destroy_bsg_class; 1097 1098 bsg_major = MAJOR(devid); 1099 1100 cdev_init(&bsg_cdev, &bsg_fops); 1101 ret = cdev_add(&bsg_cdev, MKDEV(bsg_major, 0), BSG_MAX_DEVS); 1102 if (ret) 1103 goto unregister_chrdev; 1104 1105 printk(KERN_INFO BSG_DESCRIPTION " version " BSG_VERSION 1106 " loaded (major %d)\n", bsg_major); 1107 return 0; 1108 unregister_chrdev: 1109 unregister_chrdev_region(MKDEV(bsg_major, 0), BSG_MAX_DEVS); 1110 destroy_bsg_class: 1111 class_destroy(bsg_class); 1112 destroy_kmemcache: 1113 kmem_cache_destroy(bsg_cmd_cachep); 1114 return ret; 1115 } 1116 1117 MODULE_AUTHOR("Jens Axboe"); 1118 MODULE_DESCRIPTION(BSG_DESCRIPTION); 1119 MODULE_LICENSE("GPL"); 1120 1121 device_initcall(bsg_init); 1122