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