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