1 /* 2 * bsg.c - block layer implementation of the sg v4 interface 3 * 4 * Copyright (C) 2004 Jens Axboe <axboe@suse.de> SUSE Labs 5 * Copyright (C) 2004 Peter M. Jones <pjones@redhat.com> 6 * 7 * This file is subject to the terms and conditions of the GNU General Public 8 * License version 2. See the file "COPYING" in the main directory of this 9 * archive for more details. 10 * 11 */ 12 #include <linux/module.h> 13 #include <linux/init.h> 14 #include <linux/file.h> 15 #include <linux/blkdev.h> 16 #include <linux/poll.h> 17 #include <linux/cdev.h> 18 #include <linux/percpu.h> 19 #include <linux/uio.h> 20 #include <linux/idr.h> 21 #include <linux/bsg.h> 22 #include <linux/smp_lock.h> 23 24 #include <scsi/scsi.h> 25 #include <scsi/scsi_ioctl.h> 26 #include <scsi/scsi_cmnd.h> 27 #include <scsi/scsi_device.h> 28 #include <scsi/scsi_driver.h> 29 #include <scsi/sg.h> 30 31 #define BSG_DESCRIPTION "Block layer SCSI generic (bsg) driver" 32 #define BSG_VERSION "0.4" 33 34 struct bsg_device { 35 struct request_queue *queue; 36 spinlock_t lock; 37 struct list_head busy_list; 38 struct list_head done_list; 39 struct hlist_node dev_list; 40 atomic_t ref_count; 41 int queued_cmds; 42 int done_cmds; 43 wait_queue_head_t wq_done; 44 wait_queue_head_t wq_free; 45 char name[20]; 46 int max_queue; 47 unsigned long flags; 48 }; 49 50 enum { 51 BSG_F_BLOCK = 1, 52 }; 53 54 #define BSG_DEFAULT_CMDS 64 55 #define BSG_MAX_DEVS 32768 56 57 #undef BSG_DEBUG 58 59 #ifdef BSG_DEBUG 60 #define dprintk(fmt, args...) printk(KERN_ERR "%s: " fmt, __func__, ##args) 61 #else 62 #define dprintk(fmt, args...) 63 #endif 64 65 static DEFINE_MUTEX(bsg_mutex); 66 static DEFINE_IDR(bsg_minor_idr); 67 68 #define BSG_LIST_ARRAY_SIZE 8 69 static struct hlist_head bsg_device_list[BSG_LIST_ARRAY_SIZE]; 70 71 static struct class *bsg_class; 72 static int bsg_major; 73 74 static struct kmem_cache *bsg_cmd_cachep; 75 76 /* 77 * our internal command type 78 */ 79 struct bsg_command { 80 struct bsg_device *bd; 81 struct list_head list; 82 struct request *rq; 83 struct bio *bio; 84 struct bio *bidi_bio; 85 int err; 86 struct sg_io_v4 hdr; 87 char sense[SCSI_SENSE_BUFFERSIZE]; 88 }; 89 90 static void bsg_free_command(struct bsg_command *bc) 91 { 92 struct bsg_device *bd = bc->bd; 93 unsigned long flags; 94 95 kmem_cache_free(bsg_cmd_cachep, bc); 96 97 spin_lock_irqsave(&bd->lock, flags); 98 bd->queued_cmds--; 99 spin_unlock_irqrestore(&bd->lock, flags); 100 101 wake_up(&bd->wq_free); 102 } 103 104 static struct bsg_command *bsg_alloc_command(struct bsg_device *bd) 105 { 106 struct bsg_command *bc = ERR_PTR(-EINVAL); 107 108 spin_lock_irq(&bd->lock); 109 110 if (bd->queued_cmds >= bd->max_queue) 111 goto out; 112 113 bd->queued_cmds++; 114 spin_unlock_irq(&bd->lock); 115 116 bc = kmem_cache_zalloc(bsg_cmd_cachep, GFP_KERNEL); 117 if (unlikely(!bc)) { 118 spin_lock_irq(&bd->lock); 119 bd->queued_cmds--; 120 bc = ERR_PTR(-ENOMEM); 121 goto out; 122 } 123 124 bc->bd = bd; 125 INIT_LIST_HEAD(&bc->list); 126 dprintk("%s: returning free cmd %p\n", bd->name, bc); 127 return bc; 128 out: 129 spin_unlock_irq(&bd->lock); 130 return bc; 131 } 132 133 static inline struct hlist_head *bsg_dev_idx_hash(int index) 134 { 135 return &bsg_device_list[index & (BSG_LIST_ARRAY_SIZE - 1)]; 136 } 137 138 static int bsg_io_schedule(struct bsg_device *bd) 139 { 140 DEFINE_WAIT(wait); 141 int ret = 0; 142 143 spin_lock_irq(&bd->lock); 144 145 BUG_ON(bd->done_cmds > bd->queued_cmds); 146 147 /* 148 * -ENOSPC or -ENODATA? I'm going for -ENODATA, meaning "I have no 149 * work to do", even though we return -ENOSPC after this same test 150 * during bsg_write() -- there, it means our buffer can't have more 151 * bsg_commands added to it, thus has no space left. 152 */ 153 if (bd->done_cmds == bd->queued_cmds) { 154 ret = -ENODATA; 155 goto unlock; 156 } 157 158 if (!test_bit(BSG_F_BLOCK, &bd->flags)) { 159 ret = -EAGAIN; 160 goto unlock; 161 } 162 163 prepare_to_wait(&bd->wq_done, &wait, TASK_UNINTERRUPTIBLE); 164 spin_unlock_irq(&bd->lock); 165 io_schedule(); 166 finish_wait(&bd->wq_done, &wait); 167 168 return ret; 169 unlock: 170 spin_unlock_irq(&bd->lock); 171 return ret; 172 } 173 174 static int blk_fill_sgv4_hdr_rq(struct request_queue *q, struct request *rq, 175 struct sg_io_v4 *hdr, struct bsg_device *bd, 176 fmode_t has_write_perm) 177 { 178 if (hdr->request_len > BLK_MAX_CDB) { 179 rq->cmd = kzalloc(hdr->request_len, GFP_KERNEL); 180 if (!rq->cmd) 181 return -ENOMEM; 182 } 183 184 if (copy_from_user(rq->cmd, (void *)(unsigned long)hdr->request, 185 hdr->request_len)) 186 return -EFAULT; 187 188 if (hdr->subprotocol == BSG_SUB_PROTOCOL_SCSI_CMD) { 189 if (blk_verify_command(&q->cmd_filter, rq->cmd, has_write_perm)) 190 return -EPERM; 191 } else if (!capable(CAP_SYS_RAWIO)) 192 return -EPERM; 193 194 /* 195 * fill in request structure 196 */ 197 rq->cmd_len = hdr->request_len; 198 rq->cmd_type = REQ_TYPE_BLOCK_PC; 199 200 rq->timeout = (hdr->timeout * HZ) / 1000; 201 if (!rq->timeout) 202 rq->timeout = q->sg_timeout; 203 if (!rq->timeout) 204 rq->timeout = BLK_DEFAULT_SG_TIMEOUT; 205 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 *dxferp = NULL; 252 253 dprintk("map hdr %llx/%u %llx/%u\n", (unsigned long long) hdr->dout_xferp, 254 hdr->dout_xfer_len, (unsigned long long) hdr->din_xferp, 255 hdr->din_xfer_len); 256 257 ret = bsg_validate_sgv4_hdr(q, hdr, &rw); 258 if (ret) 259 return ERR_PTR(ret); 260 261 /* 262 * map scatter-gather elements seperately and string them to request 263 */ 264 rq = blk_get_request(q, rw, GFP_KERNEL); 265 if (!rq) 266 return ERR_PTR(-ENOMEM); 267 ret = blk_fill_sgv4_hdr_rq(q, rq, hdr, bd, has_write_perm); 268 if (ret) 269 goto out; 270 271 if (rw == WRITE && hdr->din_xfer_len) { 272 if (!test_bit(QUEUE_FLAG_BIDI, &q->queue_flags)) { 273 ret = -EOPNOTSUPP; 274 goto out; 275 } 276 277 next_rq = blk_get_request(q, READ, GFP_KERNEL); 278 if (!next_rq) { 279 ret = -ENOMEM; 280 goto out; 281 } 282 rq->next_rq = next_rq; 283 next_rq->cmd_type = rq->cmd_type; 284 285 dxferp = (void*)(unsigned long)hdr->din_xferp; 286 ret = blk_rq_map_user(q, next_rq, NULL, dxferp, 287 hdr->din_xfer_len, GFP_KERNEL); 288 if (ret) 289 goto out; 290 } 291 292 if (hdr->dout_xfer_len) { 293 dxfer_len = hdr->dout_xfer_len; 294 dxferp = (void*)(unsigned long)hdr->dout_xferp; 295 } else if (hdr->din_xfer_len) { 296 dxfer_len = hdr->din_xfer_len; 297 dxferp = (void*)(unsigned long)hdr->din_xferp; 298 } else 299 dxfer_len = 0; 300 301 if (dxfer_len) { 302 ret = blk_rq_map_user(q, rq, NULL, dxferp, dxfer_len, 303 GFP_KERNEL); 304 if (ret) 305 goto out; 306 } 307 308 rq->sense = sense; 309 rq->sense_len = 0; 310 311 return rq; 312 out: 313 if (rq->cmd != rq->__cmd) 314 kfree(rq->cmd); 315 blk_put_request(rq); 316 if (next_rq) { 317 blk_rq_unmap_user(next_rq->bio); 318 next_rq->bio = NULL; 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 rq->next_rq->bio = NULL; 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 rq->bio = NULL; 472 blk_put_request(rq); 473 474 return ret; 475 } 476 477 static int bsg_complete_all_commands(struct bsg_device *bd) 478 { 479 struct bsg_command *bc; 480 int ret, tret; 481 482 dprintk("%s: entered\n", bd->name); 483 484 /* 485 * wait for all commands to complete 486 */ 487 ret = 0; 488 do { 489 ret = bsg_io_schedule(bd); 490 /* 491 * look for -ENODATA specifically -- we'll sometimes get 492 * -ERESTARTSYS when we've taken a signal, but we can't 493 * return until we're done freeing the queue, so ignore 494 * it. The signal will get handled when we're done freeing 495 * the bsg_device. 496 */ 497 } while (ret != -ENODATA); 498 499 /* 500 * discard done commands 501 */ 502 ret = 0; 503 do { 504 spin_lock_irq(&bd->lock); 505 if (!bd->queued_cmds) { 506 spin_unlock_irq(&bd->lock); 507 break; 508 } 509 spin_unlock_irq(&bd->lock); 510 511 bc = bsg_get_done_cmd(bd); 512 if (IS_ERR(bc)) 513 break; 514 515 tret = blk_complete_sgv4_hdr_rq(bc->rq, &bc->hdr, bc->bio, 516 bc->bidi_bio); 517 if (!ret) 518 ret = tret; 519 520 bsg_free_command(bc); 521 } while (1); 522 523 return ret; 524 } 525 526 static int 527 __bsg_read(char __user *buf, size_t count, struct bsg_device *bd, 528 const struct iovec *iov, ssize_t *bytes_read) 529 { 530 struct bsg_command *bc; 531 int nr_commands, ret; 532 533 if (count % sizeof(struct sg_io_v4)) 534 return -EINVAL; 535 536 ret = 0; 537 nr_commands = count / sizeof(struct sg_io_v4); 538 while (nr_commands) { 539 bc = bsg_get_done_cmd(bd); 540 if (IS_ERR(bc)) { 541 ret = PTR_ERR(bc); 542 break; 543 } 544 545 /* 546 * this is the only case where we need to copy data back 547 * after completing the request. so do that here, 548 * bsg_complete_work() cannot do that for us 549 */ 550 ret = blk_complete_sgv4_hdr_rq(bc->rq, &bc->hdr, bc->bio, 551 bc->bidi_bio); 552 553 if (copy_to_user(buf, &bc->hdr, sizeof(bc->hdr))) 554 ret = -EFAULT; 555 556 bsg_free_command(bc); 557 558 if (ret) 559 break; 560 561 buf += sizeof(struct sg_io_v4); 562 *bytes_read += sizeof(struct sg_io_v4); 563 nr_commands--; 564 } 565 566 return ret; 567 } 568 569 static inline void bsg_set_block(struct bsg_device *bd, struct file *file) 570 { 571 if (file->f_flags & O_NONBLOCK) 572 clear_bit(BSG_F_BLOCK, &bd->flags); 573 else 574 set_bit(BSG_F_BLOCK, &bd->flags); 575 } 576 577 /* 578 * Check if the error is a "real" error that we should return. 579 */ 580 static inline int err_block_err(int ret) 581 { 582 if (ret && ret != -ENOSPC && ret != -ENODATA && ret != -EAGAIN) 583 return 1; 584 585 return 0; 586 } 587 588 static ssize_t 589 bsg_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) 590 { 591 struct bsg_device *bd = file->private_data; 592 int ret; 593 ssize_t bytes_read; 594 595 dprintk("%s: read %Zd bytes\n", bd->name, count); 596 597 bsg_set_block(bd, file); 598 599 bytes_read = 0; 600 ret = __bsg_read(buf, count, bd, NULL, &bytes_read); 601 *ppos = bytes_read; 602 603 if (!bytes_read || (bytes_read && err_block_err(ret))) 604 bytes_read = ret; 605 606 return bytes_read; 607 } 608 609 static int __bsg_write(struct bsg_device *bd, const char __user *buf, 610 size_t count, ssize_t *bytes_written, 611 fmode_t has_write_perm) 612 { 613 struct bsg_command *bc; 614 struct request *rq; 615 int ret, nr_commands; 616 617 if (count % sizeof(struct sg_io_v4)) 618 return -EINVAL; 619 620 nr_commands = count / sizeof(struct sg_io_v4); 621 rq = NULL; 622 bc = NULL; 623 ret = 0; 624 while (nr_commands) { 625 struct request_queue *q = bd->queue; 626 627 bc = bsg_alloc_command(bd); 628 if (IS_ERR(bc)) { 629 ret = PTR_ERR(bc); 630 bc = NULL; 631 break; 632 } 633 634 if (copy_from_user(&bc->hdr, buf, sizeof(bc->hdr))) { 635 ret = -EFAULT; 636 break; 637 } 638 639 /* 640 * get a request, fill in the blanks, and add to request queue 641 */ 642 rq = bsg_map_hdr(bd, &bc->hdr, has_write_perm, bc->sense); 643 if (IS_ERR(rq)) { 644 ret = PTR_ERR(rq); 645 rq = NULL; 646 break; 647 } 648 649 bsg_add_command(bd, q, bc, rq); 650 bc = NULL; 651 rq = NULL; 652 nr_commands--; 653 buf += sizeof(struct sg_io_v4); 654 *bytes_written += sizeof(struct sg_io_v4); 655 } 656 657 if (bc) 658 bsg_free_command(bc); 659 660 return ret; 661 } 662 663 static ssize_t 664 bsg_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) 665 { 666 struct bsg_device *bd = file->private_data; 667 ssize_t bytes_written; 668 int ret; 669 670 dprintk("%s: write %Zd bytes\n", bd->name, count); 671 672 bsg_set_block(bd, file); 673 674 bytes_written = 0; 675 ret = __bsg_write(bd, buf, count, &bytes_written, 676 file->f_mode & FMODE_WRITE); 677 678 *ppos = bytes_written; 679 680 /* 681 * return bytes written on non-fatal errors 682 */ 683 if (!bytes_written || (bytes_written && err_block_err(ret))) 684 bytes_written = ret; 685 686 dprintk("%s: returning %Zd\n", bd->name, bytes_written); 687 return bytes_written; 688 } 689 690 static struct bsg_device *bsg_alloc_device(void) 691 { 692 struct bsg_device *bd; 693 694 bd = kzalloc(sizeof(struct bsg_device), GFP_KERNEL); 695 if (unlikely(!bd)) 696 return NULL; 697 698 spin_lock_init(&bd->lock); 699 700 bd->max_queue = BSG_DEFAULT_CMDS; 701 702 INIT_LIST_HEAD(&bd->busy_list); 703 INIT_LIST_HEAD(&bd->done_list); 704 INIT_HLIST_NODE(&bd->dev_list); 705 706 init_waitqueue_head(&bd->wq_free); 707 init_waitqueue_head(&bd->wq_done); 708 return bd; 709 } 710 711 static void bsg_kref_release_function(struct kref *kref) 712 { 713 struct bsg_class_device *bcd = 714 container_of(kref, struct bsg_class_device, ref); 715 struct device *parent = bcd->parent; 716 717 if (bcd->release) 718 bcd->release(bcd->parent); 719 720 put_device(parent); 721 } 722 723 static int bsg_put_device(struct bsg_device *bd) 724 { 725 int ret = 0, do_free; 726 struct request_queue *q = bd->queue; 727 728 mutex_lock(&bsg_mutex); 729 730 do_free = atomic_dec_and_test(&bd->ref_count); 731 if (!do_free) { 732 mutex_unlock(&bsg_mutex); 733 goto out; 734 } 735 736 hlist_del(&bd->dev_list); 737 mutex_unlock(&bsg_mutex); 738 739 dprintk("%s: tearing down\n", bd->name); 740 741 /* 742 * close can always block 743 */ 744 set_bit(BSG_F_BLOCK, &bd->flags); 745 746 /* 747 * correct error detection baddies here again. it's the responsibility 748 * of the app to properly reap commands before close() if it wants 749 * fool-proof error detection 750 */ 751 ret = bsg_complete_all_commands(bd); 752 753 kfree(bd); 754 out: 755 kref_put(&q->bsg_dev.ref, bsg_kref_release_function); 756 if (do_free) 757 blk_put_queue(q); 758 return ret; 759 } 760 761 static struct bsg_device *bsg_add_device(struct inode *inode, 762 struct request_queue *rq, 763 struct file *file) 764 { 765 struct bsg_device *bd; 766 int ret; 767 #ifdef BSG_DEBUG 768 unsigned char buf[32]; 769 #endif 770 ret = blk_get_queue(rq); 771 if (ret) 772 return ERR_PTR(-ENXIO); 773 774 bd = bsg_alloc_device(); 775 if (!bd) { 776 blk_put_queue(rq); 777 return ERR_PTR(-ENOMEM); 778 } 779 780 bd->queue = rq; 781 782 bsg_set_block(bd, file); 783 784 atomic_set(&bd->ref_count, 1); 785 mutex_lock(&bsg_mutex); 786 hlist_add_head(&bd->dev_list, bsg_dev_idx_hash(iminor(inode))); 787 788 strncpy(bd->name, dev_name(rq->bsg_dev.class_dev), sizeof(bd->name) - 1); 789 dprintk("bound to <%s>, max queue %d\n", 790 format_dev_t(buf, inode->i_rdev), bd->max_queue); 791 792 mutex_unlock(&bsg_mutex); 793 return bd; 794 } 795 796 static struct bsg_device *__bsg_get_device(int minor, struct request_queue *q) 797 { 798 struct bsg_device *bd; 799 struct hlist_node *entry; 800 801 mutex_lock(&bsg_mutex); 802 803 hlist_for_each_entry(bd, entry, bsg_dev_idx_hash(minor), dev_list) { 804 if (bd->queue == q) { 805 atomic_inc(&bd->ref_count); 806 goto found; 807 } 808 } 809 bd = NULL; 810 found: 811 mutex_unlock(&bsg_mutex); 812 return bd; 813 } 814 815 static struct bsg_device *bsg_get_device(struct inode *inode, struct file *file) 816 { 817 struct bsg_device *bd; 818 struct bsg_class_device *bcd; 819 820 /* 821 * find the class device 822 */ 823 mutex_lock(&bsg_mutex); 824 bcd = idr_find(&bsg_minor_idr, iminor(inode)); 825 if (bcd) 826 kref_get(&bcd->ref); 827 mutex_unlock(&bsg_mutex); 828 829 if (!bcd) 830 return ERR_PTR(-ENODEV); 831 832 bd = __bsg_get_device(iminor(inode), bcd->queue); 833 if (bd) 834 return bd; 835 836 bd = bsg_add_device(inode, bcd->queue, file); 837 if (IS_ERR(bd)) 838 kref_put(&bcd->ref, bsg_kref_release_function); 839 840 return bd; 841 } 842 843 static int bsg_open(struct inode *inode, struct file *file) 844 { 845 struct bsg_device *bd; 846 847 lock_kernel(); 848 bd = bsg_get_device(inode, file); 849 unlock_kernel(); 850 851 if (IS_ERR(bd)) 852 return PTR_ERR(bd); 853 854 file->private_data = bd; 855 return 0; 856 } 857 858 static int bsg_release(struct inode *inode, struct file *file) 859 { 860 struct bsg_device *bd = file->private_data; 861 862 file->private_data = NULL; 863 return bsg_put_device(bd); 864 } 865 866 static unsigned int bsg_poll(struct file *file, poll_table *wait) 867 { 868 struct bsg_device *bd = file->private_data; 869 unsigned int mask = 0; 870 871 poll_wait(file, &bd->wq_done, wait); 872 poll_wait(file, &bd->wq_free, wait); 873 874 spin_lock_irq(&bd->lock); 875 if (!list_empty(&bd->done_list)) 876 mask |= POLLIN | POLLRDNORM; 877 if (bd->queued_cmds >= bd->max_queue) 878 mask |= POLLOUT; 879 spin_unlock_irq(&bd->lock); 880 881 return mask; 882 } 883 884 static long bsg_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 885 { 886 struct bsg_device *bd = file->private_data; 887 int __user *uarg = (int __user *) arg; 888 int ret; 889 890 switch (cmd) { 891 /* 892 * our own ioctls 893 */ 894 case SG_GET_COMMAND_Q: 895 return put_user(bd->max_queue, uarg); 896 case SG_SET_COMMAND_Q: { 897 int queue; 898 899 if (get_user(queue, uarg)) 900 return -EFAULT; 901 if (queue < 1) 902 return -EINVAL; 903 904 spin_lock_irq(&bd->lock); 905 bd->max_queue = queue; 906 spin_unlock_irq(&bd->lock); 907 return 0; 908 } 909 910 /* 911 * SCSI/sg ioctls 912 */ 913 case SG_GET_VERSION_NUM: 914 case SCSI_IOCTL_GET_IDLUN: 915 case SCSI_IOCTL_GET_BUS_NUMBER: 916 case SG_SET_TIMEOUT: 917 case SG_GET_TIMEOUT: 918 case SG_GET_RESERVED_SIZE: 919 case SG_SET_RESERVED_SIZE: 920 case SG_EMULATED_HOST: 921 case SCSI_IOCTL_SEND_COMMAND: { 922 void __user *uarg = (void __user *) arg; 923 return scsi_cmd_ioctl(bd->queue, NULL, file->f_mode, cmd, uarg); 924 } 925 case SG_IO: { 926 struct request *rq; 927 struct bio *bio, *bidi_bio = NULL; 928 struct sg_io_v4 hdr; 929 int at_head; 930 u8 sense[SCSI_SENSE_BUFFERSIZE]; 931 932 if (copy_from_user(&hdr, uarg, sizeof(hdr))) 933 return -EFAULT; 934 935 rq = bsg_map_hdr(bd, &hdr, file->f_mode & FMODE_WRITE, sense); 936 if (IS_ERR(rq)) 937 return PTR_ERR(rq); 938 939 bio = rq->bio; 940 if (rq->next_rq) 941 bidi_bio = rq->next_rq->bio; 942 943 at_head = (0 == (hdr.flags & BSG_FLAG_Q_AT_TAIL)); 944 blk_execute_rq(bd->queue, NULL, rq, at_head); 945 ret = blk_complete_sgv4_hdr_rq(rq, &hdr, bio, bidi_bio); 946 947 if (copy_to_user(uarg, &hdr, sizeof(hdr))) 948 return -EFAULT; 949 950 return ret; 951 } 952 /* 953 * block device ioctls 954 */ 955 default: 956 #if 0 957 return ioctl_by_bdev(bd->bdev, cmd, arg); 958 #else 959 return -ENOTTY; 960 #endif 961 } 962 } 963 964 static const struct file_operations bsg_fops = { 965 .read = bsg_read, 966 .write = bsg_write, 967 .poll = bsg_poll, 968 .open = bsg_open, 969 .release = bsg_release, 970 .unlocked_ioctl = bsg_ioctl, 971 .owner = THIS_MODULE, 972 }; 973 974 void bsg_unregister_queue(struct request_queue *q) 975 { 976 struct bsg_class_device *bcd = &q->bsg_dev; 977 978 if (!bcd->class_dev) 979 return; 980 981 mutex_lock(&bsg_mutex); 982 idr_remove(&bsg_minor_idr, bcd->minor); 983 sysfs_remove_link(&q->kobj, "bsg"); 984 device_unregister(bcd->class_dev); 985 bcd->class_dev = NULL; 986 kref_put(&bcd->ref, bsg_kref_release_function); 987 mutex_unlock(&bsg_mutex); 988 } 989 EXPORT_SYMBOL_GPL(bsg_unregister_queue); 990 991 int bsg_register_queue(struct request_queue *q, struct device *parent, 992 const char *name, void (*release)(struct device *)) 993 { 994 struct bsg_class_device *bcd; 995 dev_t dev; 996 int ret, minor; 997 struct device *class_dev = NULL; 998 const char *devname; 999 1000 if (name) 1001 devname = name; 1002 else 1003 devname = dev_name(parent); 1004 1005 /* 1006 * we need a proper transport to send commands, not a stacked device 1007 */ 1008 if (!q->request_fn) 1009 return 0; 1010 1011 bcd = &q->bsg_dev; 1012 memset(bcd, 0, sizeof(*bcd)); 1013 1014 mutex_lock(&bsg_mutex); 1015 1016 ret = idr_pre_get(&bsg_minor_idr, GFP_KERNEL); 1017 if (!ret) { 1018 ret = -ENOMEM; 1019 goto unlock; 1020 } 1021 1022 ret = idr_get_new(&bsg_minor_idr, bcd, &minor); 1023 if (ret < 0) 1024 goto unlock; 1025 1026 if (minor >= BSG_MAX_DEVS) { 1027 printk(KERN_ERR "bsg: too many bsg devices\n"); 1028 ret = -EINVAL; 1029 goto remove_idr; 1030 } 1031 1032 bcd->minor = minor; 1033 bcd->queue = q; 1034 bcd->parent = get_device(parent); 1035 bcd->release = release; 1036 kref_init(&bcd->ref); 1037 dev = MKDEV(bsg_major, bcd->minor); 1038 class_dev = device_create(bsg_class, parent, dev, NULL, "%s", devname); 1039 if (IS_ERR(class_dev)) { 1040 ret = PTR_ERR(class_dev); 1041 goto put_dev; 1042 } 1043 bcd->class_dev = class_dev; 1044 1045 if (q->kobj.sd) { 1046 ret = sysfs_create_link(&q->kobj, &bcd->class_dev->kobj, "bsg"); 1047 if (ret) 1048 goto unregister_class_dev; 1049 } 1050 1051 mutex_unlock(&bsg_mutex); 1052 return 0; 1053 1054 unregister_class_dev: 1055 device_unregister(class_dev); 1056 put_dev: 1057 put_device(parent); 1058 remove_idr: 1059 idr_remove(&bsg_minor_idr, minor); 1060 unlock: 1061 mutex_unlock(&bsg_mutex); 1062 return ret; 1063 } 1064 EXPORT_SYMBOL_GPL(bsg_register_queue); 1065 1066 static struct cdev bsg_cdev; 1067 1068 static char *bsg_nodename(struct device *dev) 1069 { 1070 return kasprintf(GFP_KERNEL, "bsg/%s", dev_name(dev)); 1071 } 1072 1073 static int __init bsg_init(void) 1074 { 1075 int ret, i; 1076 dev_t devid; 1077 1078 bsg_cmd_cachep = kmem_cache_create("bsg_cmd", 1079 sizeof(struct bsg_command), 0, 0, NULL); 1080 if (!bsg_cmd_cachep) { 1081 printk(KERN_ERR "bsg: failed creating slab cache\n"); 1082 return -ENOMEM; 1083 } 1084 1085 for (i = 0; i < BSG_LIST_ARRAY_SIZE; i++) 1086 INIT_HLIST_HEAD(&bsg_device_list[i]); 1087 1088 bsg_class = class_create(THIS_MODULE, "bsg"); 1089 if (IS_ERR(bsg_class)) { 1090 ret = PTR_ERR(bsg_class); 1091 goto destroy_kmemcache; 1092 } 1093 bsg_class->nodename = bsg_nodename; 1094 1095 ret = alloc_chrdev_region(&devid, 0, BSG_MAX_DEVS, "bsg"); 1096 if (ret) 1097 goto destroy_bsg_class; 1098 1099 bsg_major = MAJOR(devid); 1100 1101 cdev_init(&bsg_cdev, &bsg_fops); 1102 ret = cdev_add(&bsg_cdev, MKDEV(bsg_major, 0), BSG_MAX_DEVS); 1103 if (ret) 1104 goto unregister_chrdev; 1105 1106 printk(KERN_INFO BSG_DESCRIPTION " version " BSG_VERSION 1107 " loaded (major %d)\n", bsg_major); 1108 return 0; 1109 unregister_chrdev: 1110 unregister_chrdev_region(MKDEV(bsg_major, 0), BSG_MAX_DEVS); 1111 destroy_bsg_class: 1112 class_destroy(bsg_class); 1113 destroy_kmemcache: 1114 kmem_cache_destroy(bsg_cmd_cachep); 1115 return ret; 1116 } 1117 1118 MODULE_AUTHOR("Jens Axboe"); 1119 MODULE_DESCRIPTION(BSG_DESCRIPTION); 1120 MODULE_LICENSE("GPL"); 1121 1122 device_initcall(bsg_init); 1123