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