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[BUS_ID_SIZE]; 46 int max_queue; 47 unsigned long flags; 48 struct blk_scsi_cmd_filter *cmd_filter; 49 mode_t *f_mode; 50 }; 51 52 enum { 53 BSG_F_BLOCK = 1, 54 }; 55 56 #define BSG_DEFAULT_CMDS 64 57 #define BSG_MAX_DEVS 32768 58 59 #undef BSG_DEBUG 60 61 #ifdef BSG_DEBUG 62 #define dprintk(fmt, args...) printk(KERN_ERR "%s: " fmt, __func__, ##args) 63 #else 64 #define dprintk(fmt, args...) 65 #endif 66 67 static DEFINE_MUTEX(bsg_mutex); 68 static DEFINE_IDR(bsg_minor_idr); 69 70 #define BSG_LIST_ARRAY_SIZE 8 71 static struct hlist_head bsg_device_list[BSG_LIST_ARRAY_SIZE]; 72 73 static struct class *bsg_class; 74 static int bsg_major; 75 76 static struct kmem_cache *bsg_cmd_cachep; 77 78 /* 79 * our internal command type 80 */ 81 struct bsg_command { 82 struct bsg_device *bd; 83 struct list_head list; 84 struct request *rq; 85 struct bio *bio; 86 struct bio *bidi_bio; 87 int err; 88 struct sg_io_v4 hdr; 89 char sense[SCSI_SENSE_BUFFERSIZE]; 90 }; 91 92 static void bsg_free_command(struct bsg_command *bc) 93 { 94 struct bsg_device *bd = bc->bd; 95 unsigned long flags; 96 97 kmem_cache_free(bsg_cmd_cachep, bc); 98 99 spin_lock_irqsave(&bd->lock, flags); 100 bd->queued_cmds--; 101 spin_unlock_irqrestore(&bd->lock, flags); 102 103 wake_up(&bd->wq_free); 104 } 105 106 static struct bsg_command *bsg_alloc_command(struct bsg_device *bd) 107 { 108 struct bsg_command *bc = ERR_PTR(-EINVAL); 109 110 spin_lock_irq(&bd->lock); 111 112 if (bd->queued_cmds >= bd->max_queue) 113 goto out; 114 115 bd->queued_cmds++; 116 spin_unlock_irq(&bd->lock); 117 118 bc = kmem_cache_zalloc(bsg_cmd_cachep, GFP_KERNEL); 119 if (unlikely(!bc)) { 120 spin_lock_irq(&bd->lock); 121 bd->queued_cmds--; 122 bc = ERR_PTR(-ENOMEM); 123 goto out; 124 } 125 126 bc->bd = bd; 127 INIT_LIST_HEAD(&bc->list); 128 dprintk("%s: returning free cmd %p\n", bd->name, bc); 129 return bc; 130 out: 131 spin_unlock_irq(&bd->lock); 132 return bc; 133 } 134 135 static inline struct hlist_head *bsg_dev_idx_hash(int index) 136 { 137 return &bsg_device_list[index & (BSG_LIST_ARRAY_SIZE - 1)]; 138 } 139 140 static int bsg_io_schedule(struct bsg_device *bd) 141 { 142 DEFINE_WAIT(wait); 143 int ret = 0; 144 145 spin_lock_irq(&bd->lock); 146 147 BUG_ON(bd->done_cmds > bd->queued_cmds); 148 149 /* 150 * -ENOSPC or -ENODATA? I'm going for -ENODATA, meaning "I have no 151 * work to do", even though we return -ENOSPC after this same test 152 * during bsg_write() -- there, it means our buffer can't have more 153 * bsg_commands added to it, thus has no space left. 154 */ 155 if (bd->done_cmds == bd->queued_cmds) { 156 ret = -ENODATA; 157 goto unlock; 158 } 159 160 if (!test_bit(BSG_F_BLOCK, &bd->flags)) { 161 ret = -EAGAIN; 162 goto unlock; 163 } 164 165 prepare_to_wait(&bd->wq_done, &wait, TASK_UNINTERRUPTIBLE); 166 spin_unlock_irq(&bd->lock); 167 io_schedule(); 168 finish_wait(&bd->wq_done, &wait); 169 170 return ret; 171 unlock: 172 spin_unlock_irq(&bd->lock); 173 return ret; 174 } 175 176 static int blk_fill_sgv4_hdr_rq(struct request_queue *q, struct request *rq, 177 struct sg_io_v4 *hdr, struct bsg_device *bd) 178 { 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_cmd_filter_verify_command(bd->cmd_filter, rq->cmd, 191 bd->f_mode)) 192 return -EPERM; 193 } else if (!capable(CAP_SYS_RAWIO)) 194 return -EPERM; 195 196 /* 197 * fill in request structure 198 */ 199 rq->cmd_len = hdr->request_len; 200 rq->cmd_type = REQ_TYPE_BLOCK_PC; 201 202 rq->timeout = (hdr->timeout * HZ) / 1000; 203 if (!rq->timeout) 204 rq->timeout = q->sg_timeout; 205 if (!rq->timeout) 206 rq->timeout = BLK_DEFAULT_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 if (hdr->dout_xfer_len > (q->max_sectors << 9) || 222 hdr->din_xfer_len > (q->max_sectors << 9)) 223 return -EIO; 224 225 switch (hdr->protocol) { 226 case BSG_PROTOCOL_SCSI: 227 switch (hdr->subprotocol) { 228 case BSG_SUB_PROTOCOL_SCSI_CMD: 229 case BSG_SUB_PROTOCOL_SCSI_TRANSPORT: 230 break; 231 default: 232 ret = -EINVAL; 233 } 234 break; 235 default: 236 ret = -EINVAL; 237 } 238 239 *rw = hdr->dout_xfer_len ? WRITE : READ; 240 return ret; 241 } 242 243 /* 244 * map sg_io_v4 to a request. 245 */ 246 static struct request * 247 bsg_map_hdr(struct bsg_device *bd, struct sg_io_v4 *hdr) 248 { 249 struct request_queue *q = bd->queue; 250 struct request *rq, *next_rq = NULL; 251 int ret, rw; 252 unsigned int dxfer_len; 253 void *dxferp = NULL; 254 255 dprintk("map hdr %llx/%u %llx/%u\n", (unsigned long long) hdr->dout_xferp, 256 hdr->dout_xfer_len, (unsigned long long) hdr->din_xferp, 257 hdr->din_xfer_len); 258 259 ret = bsg_validate_sgv4_hdr(q, hdr, &rw); 260 if (ret) 261 return ERR_PTR(ret); 262 263 /* 264 * map scatter-gather elements seperately and string them to request 265 */ 266 rq = blk_get_request(q, rw, GFP_KERNEL); 267 if (!rq) 268 return ERR_PTR(-ENOMEM); 269 ret = blk_fill_sgv4_hdr_rq(q, rq, hdr, bd); 270 if (ret) 271 goto out; 272 273 if (rw == WRITE && hdr->din_xfer_len) { 274 if (!test_bit(QUEUE_FLAG_BIDI, &q->queue_flags)) { 275 ret = -EOPNOTSUPP; 276 goto out; 277 } 278 279 next_rq = blk_get_request(q, READ, GFP_KERNEL); 280 if (!next_rq) { 281 ret = -ENOMEM; 282 goto out; 283 } 284 rq->next_rq = next_rq; 285 next_rq->cmd_type = rq->cmd_type; 286 287 dxferp = (void*)(unsigned long)hdr->din_xferp; 288 ret = blk_rq_map_user(q, next_rq, dxferp, hdr->din_xfer_len); 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, dxferp, dxfer_len); 304 if (ret) 305 goto out; 306 } 307 return rq; 308 out: 309 if (rq->cmd != rq->__cmd) 310 kfree(rq->cmd); 311 blk_put_request(rq); 312 if (next_rq) { 313 blk_rq_unmap_user(next_rq->bio); 314 blk_put_request(next_rq); 315 } 316 return ERR_PTR(ret); 317 } 318 319 /* 320 * async completion call-back from the block layer, when scsi/ide/whatever 321 * calls end_that_request_last() on a request 322 */ 323 static void bsg_rq_end_io(struct request *rq, int uptodate) 324 { 325 struct bsg_command *bc = rq->end_io_data; 326 struct bsg_device *bd = bc->bd; 327 unsigned long flags; 328 329 dprintk("%s: finished rq %p bc %p, bio %p stat %d\n", 330 bd->name, rq, bc, bc->bio, uptodate); 331 332 bc->hdr.duration = jiffies_to_msecs(jiffies - bc->hdr.duration); 333 334 spin_lock_irqsave(&bd->lock, flags); 335 list_move_tail(&bc->list, &bd->done_list); 336 bd->done_cmds++; 337 spin_unlock_irqrestore(&bd->lock, flags); 338 339 wake_up(&bd->wq_done); 340 } 341 342 /* 343 * do final setup of a 'bc' and submit the matching 'rq' to the block 344 * layer for io 345 */ 346 static void bsg_add_command(struct bsg_device *bd, struct request_queue *q, 347 struct bsg_command *bc, struct request *rq) 348 { 349 rq->sense = bc->sense; 350 rq->sense_len = 0; 351 352 /* 353 * add bc command to busy queue and submit rq for io 354 */ 355 bc->rq = rq; 356 bc->bio = rq->bio; 357 if (rq->next_rq) 358 bc->bidi_bio = rq->next_rq->bio; 359 bc->hdr.duration = jiffies; 360 spin_lock_irq(&bd->lock); 361 list_add_tail(&bc->list, &bd->busy_list); 362 spin_unlock_irq(&bd->lock); 363 364 dprintk("%s: queueing rq %p, bc %p\n", bd->name, rq, bc); 365 366 rq->end_io_data = bc; 367 blk_execute_rq_nowait(q, NULL, rq, 1, bsg_rq_end_io); 368 } 369 370 static struct bsg_command *bsg_next_done_cmd(struct bsg_device *bd) 371 { 372 struct bsg_command *bc = NULL; 373 374 spin_lock_irq(&bd->lock); 375 if (bd->done_cmds) { 376 bc = list_first_entry(&bd->done_list, struct bsg_command, list); 377 list_del(&bc->list); 378 bd->done_cmds--; 379 } 380 spin_unlock_irq(&bd->lock); 381 382 return bc; 383 } 384 385 /* 386 * Get a finished command from the done list 387 */ 388 static struct bsg_command *bsg_get_done_cmd(struct bsg_device *bd) 389 { 390 struct bsg_command *bc; 391 int ret; 392 393 do { 394 bc = bsg_next_done_cmd(bd); 395 if (bc) 396 break; 397 398 if (!test_bit(BSG_F_BLOCK, &bd->flags)) { 399 bc = ERR_PTR(-EAGAIN); 400 break; 401 } 402 403 ret = wait_event_interruptible(bd->wq_done, bd->done_cmds); 404 if (ret) { 405 bc = ERR_PTR(-ERESTARTSYS); 406 break; 407 } 408 } while (1); 409 410 dprintk("%s: returning done %p\n", bd->name, bc); 411 412 return bc; 413 } 414 415 static int blk_complete_sgv4_hdr_rq(struct request *rq, struct sg_io_v4 *hdr, 416 struct bio *bio, struct bio *bidi_bio) 417 { 418 int ret = 0; 419 420 dprintk("rq %p bio %p %u\n", rq, bio, rq->errors); 421 /* 422 * fill in all the output members 423 */ 424 hdr->device_status = status_byte(rq->errors); 425 hdr->transport_status = host_byte(rq->errors); 426 hdr->driver_status = driver_byte(rq->errors); 427 hdr->info = 0; 428 if (hdr->device_status || hdr->transport_status || hdr->driver_status) 429 hdr->info |= SG_INFO_CHECK; 430 hdr->response_len = 0; 431 432 if (rq->sense_len && hdr->response) { 433 int len = min_t(unsigned int, hdr->max_response_len, 434 rq->sense_len); 435 436 ret = copy_to_user((void*)(unsigned long)hdr->response, 437 rq->sense, len); 438 if (!ret) 439 hdr->response_len = len; 440 else 441 ret = -EFAULT; 442 } 443 444 if (rq->next_rq) { 445 hdr->dout_resid = rq->data_len; 446 hdr->din_resid = rq->next_rq->data_len; 447 blk_rq_unmap_user(bidi_bio); 448 blk_put_request(rq->next_rq); 449 } else if (rq_data_dir(rq) == READ) 450 hdr->din_resid = rq->data_len; 451 else 452 hdr->dout_resid = rq->data_len; 453 454 /* 455 * If the request generated a negative error number, return it 456 * (providing we aren't already returning an error); if it's 457 * just a protocol response (i.e. non negative), that gets 458 * processed above. 459 */ 460 if (!ret && rq->errors < 0) 461 ret = rq->errors; 462 463 blk_rq_unmap_user(bio); 464 if (rq->cmd != rq->__cmd) 465 kfree(rq->cmd); 466 blk_put_request(rq); 467 468 return ret; 469 } 470 471 static int bsg_complete_all_commands(struct bsg_device *bd) 472 { 473 struct bsg_command *bc; 474 int ret, tret; 475 476 dprintk("%s: entered\n", bd->name); 477 478 /* 479 * wait for all commands to complete 480 */ 481 ret = 0; 482 do { 483 ret = bsg_io_schedule(bd); 484 /* 485 * look for -ENODATA specifically -- we'll sometimes get 486 * -ERESTARTSYS when we've taken a signal, but we can't 487 * return until we're done freeing the queue, so ignore 488 * it. The signal will get handled when we're done freeing 489 * the bsg_device. 490 */ 491 } while (ret != -ENODATA); 492 493 /* 494 * discard done commands 495 */ 496 ret = 0; 497 do { 498 spin_lock_irq(&bd->lock); 499 if (!bd->queued_cmds) { 500 spin_unlock_irq(&bd->lock); 501 break; 502 } 503 spin_unlock_irq(&bd->lock); 504 505 bc = bsg_get_done_cmd(bd); 506 if (IS_ERR(bc)) 507 break; 508 509 tret = blk_complete_sgv4_hdr_rq(bc->rq, &bc->hdr, bc->bio, 510 bc->bidi_bio); 511 if (!ret) 512 ret = tret; 513 514 bsg_free_command(bc); 515 } while (1); 516 517 return ret; 518 } 519 520 static int 521 __bsg_read(char __user *buf, size_t count, struct bsg_device *bd, 522 const struct iovec *iov, ssize_t *bytes_read) 523 { 524 struct bsg_command *bc; 525 int nr_commands, ret; 526 527 if (count % sizeof(struct sg_io_v4)) 528 return -EINVAL; 529 530 ret = 0; 531 nr_commands = count / sizeof(struct sg_io_v4); 532 while (nr_commands) { 533 bc = bsg_get_done_cmd(bd); 534 if (IS_ERR(bc)) { 535 ret = PTR_ERR(bc); 536 break; 537 } 538 539 /* 540 * this is the only case where we need to copy data back 541 * after completing the request. so do that here, 542 * bsg_complete_work() cannot do that for us 543 */ 544 ret = blk_complete_sgv4_hdr_rq(bc->rq, &bc->hdr, bc->bio, 545 bc->bidi_bio); 546 547 if (copy_to_user(buf, &bc->hdr, sizeof(bc->hdr))) 548 ret = -EFAULT; 549 550 bsg_free_command(bc); 551 552 if (ret) 553 break; 554 555 buf += sizeof(struct sg_io_v4); 556 *bytes_read += sizeof(struct sg_io_v4); 557 nr_commands--; 558 } 559 560 return ret; 561 } 562 563 static inline void bsg_set_block(struct bsg_device *bd, struct file *file) 564 { 565 if (file->f_flags & O_NONBLOCK) 566 clear_bit(BSG_F_BLOCK, &bd->flags); 567 else 568 set_bit(BSG_F_BLOCK, &bd->flags); 569 } 570 571 static void bsg_set_cmd_filter(struct bsg_device *bd, 572 struct file *file) 573 { 574 struct inode *inode; 575 struct gendisk *disk; 576 577 if (!file) 578 return; 579 580 inode = file->f_dentry->d_inode; 581 if (!inode) 582 return; 583 584 disk = inode->i_bdev->bd_disk; 585 586 bd->cmd_filter = &disk->cmd_filter; 587 bd->f_mode = &file->f_mode; 588 } 589 590 /* 591 * Check if the error is a "real" error that we should return. 592 */ 593 static inline int err_block_err(int ret) 594 { 595 if (ret && ret != -ENOSPC && ret != -ENODATA && ret != -EAGAIN) 596 return 1; 597 598 return 0; 599 } 600 601 static ssize_t 602 bsg_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) 603 { 604 struct bsg_device *bd = file->private_data; 605 int ret; 606 ssize_t bytes_read; 607 608 dprintk("%s: read %Zd bytes\n", bd->name, count); 609 610 bsg_set_block(bd, file); 611 bsg_set_cmd_filter(bd, file); 612 613 bytes_read = 0; 614 ret = __bsg_read(buf, count, bd, NULL, &bytes_read); 615 *ppos = bytes_read; 616 617 if (!bytes_read || (bytes_read && err_block_err(ret))) 618 bytes_read = ret; 619 620 return bytes_read; 621 } 622 623 static int __bsg_write(struct bsg_device *bd, const char __user *buf, 624 size_t count, ssize_t *bytes_written) 625 { 626 struct bsg_command *bc; 627 struct request *rq; 628 int ret, nr_commands; 629 630 if (count % sizeof(struct sg_io_v4)) 631 return -EINVAL; 632 633 nr_commands = count / sizeof(struct sg_io_v4); 634 rq = NULL; 635 bc = NULL; 636 ret = 0; 637 while (nr_commands) { 638 struct request_queue *q = bd->queue; 639 640 bc = bsg_alloc_command(bd); 641 if (IS_ERR(bc)) { 642 ret = PTR_ERR(bc); 643 bc = NULL; 644 break; 645 } 646 647 if (copy_from_user(&bc->hdr, buf, sizeof(bc->hdr))) { 648 ret = -EFAULT; 649 break; 650 } 651 652 /* 653 * get a request, fill in the blanks, and add to request queue 654 */ 655 rq = bsg_map_hdr(bd, &bc->hdr); 656 if (IS_ERR(rq)) { 657 ret = PTR_ERR(rq); 658 rq = NULL; 659 break; 660 } 661 662 bsg_add_command(bd, q, bc, rq); 663 bc = NULL; 664 rq = NULL; 665 nr_commands--; 666 buf += sizeof(struct sg_io_v4); 667 *bytes_written += sizeof(struct sg_io_v4); 668 } 669 670 if (bc) 671 bsg_free_command(bc); 672 673 return ret; 674 } 675 676 static ssize_t 677 bsg_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) 678 { 679 struct bsg_device *bd = file->private_data; 680 ssize_t bytes_written; 681 int ret; 682 683 dprintk("%s: write %Zd bytes\n", bd->name, count); 684 685 bsg_set_block(bd, file); 686 bsg_set_cmd_filter(bd, file); 687 688 bytes_written = 0; 689 ret = __bsg_write(bd, buf, count, &bytes_written); 690 *ppos = bytes_written; 691 692 /* 693 * return bytes written on non-fatal errors 694 */ 695 if (!bytes_written || (bytes_written && err_block_err(ret))) 696 bytes_written = ret; 697 698 dprintk("%s: returning %Zd\n", bd->name, bytes_written); 699 return bytes_written; 700 } 701 702 static struct bsg_device *bsg_alloc_device(void) 703 { 704 struct bsg_device *bd; 705 706 bd = kzalloc(sizeof(struct bsg_device), GFP_KERNEL); 707 if (unlikely(!bd)) 708 return NULL; 709 710 spin_lock_init(&bd->lock); 711 712 bd->max_queue = BSG_DEFAULT_CMDS; 713 714 INIT_LIST_HEAD(&bd->busy_list); 715 INIT_LIST_HEAD(&bd->done_list); 716 INIT_HLIST_NODE(&bd->dev_list); 717 718 init_waitqueue_head(&bd->wq_free); 719 init_waitqueue_head(&bd->wq_done); 720 return bd; 721 } 722 723 static void bsg_kref_release_function(struct kref *kref) 724 { 725 struct bsg_class_device *bcd = 726 container_of(kref, struct bsg_class_device, ref); 727 struct device *parent = bcd->parent; 728 729 if (bcd->release) 730 bcd->release(bcd->parent); 731 732 put_device(parent); 733 } 734 735 static int bsg_put_device(struct bsg_device *bd) 736 { 737 int ret = 0, do_free; 738 struct request_queue *q = bd->queue; 739 740 mutex_lock(&bsg_mutex); 741 742 do_free = atomic_dec_and_test(&bd->ref_count); 743 if (!do_free) { 744 mutex_unlock(&bsg_mutex); 745 goto out; 746 } 747 748 hlist_del(&bd->dev_list); 749 mutex_unlock(&bsg_mutex); 750 751 dprintk("%s: tearing down\n", bd->name); 752 753 /* 754 * close can always block 755 */ 756 set_bit(BSG_F_BLOCK, &bd->flags); 757 758 /* 759 * correct error detection baddies here again. it's the responsibility 760 * of the app to properly reap commands before close() if it wants 761 * fool-proof error detection 762 */ 763 ret = bsg_complete_all_commands(bd); 764 765 kfree(bd); 766 out: 767 kref_put(&q->bsg_dev.ref, bsg_kref_release_function); 768 if (do_free) 769 blk_put_queue(q); 770 return ret; 771 } 772 773 static struct bsg_device *bsg_add_device(struct inode *inode, 774 struct request_queue *rq, 775 struct file *file) 776 { 777 struct bsg_device *bd; 778 int ret; 779 #ifdef BSG_DEBUG 780 unsigned char buf[32]; 781 #endif 782 ret = blk_get_queue(rq); 783 if (ret) 784 return ERR_PTR(-ENXIO); 785 786 bd = bsg_alloc_device(); 787 if (!bd) { 788 blk_put_queue(rq); 789 return ERR_PTR(-ENOMEM); 790 } 791 792 bd->queue = rq; 793 794 bsg_set_block(bd, file); 795 bsg_set_cmd_filter(bd, file); 796 797 atomic_set(&bd->ref_count, 1); 798 mutex_lock(&bsg_mutex); 799 hlist_add_head(&bd->dev_list, bsg_dev_idx_hash(iminor(inode))); 800 801 strncpy(bd->name, rq->bsg_dev.class_dev->bus_id, sizeof(bd->name) - 1); 802 dprintk("bound to <%s>, max queue %d\n", 803 format_dev_t(buf, inode->i_rdev), bd->max_queue); 804 805 mutex_unlock(&bsg_mutex); 806 return bd; 807 } 808 809 static struct bsg_device *__bsg_get_device(int minor, struct request_queue *q) 810 { 811 struct bsg_device *bd; 812 struct hlist_node *entry; 813 814 mutex_lock(&bsg_mutex); 815 816 hlist_for_each_entry(bd, entry, bsg_dev_idx_hash(minor), dev_list) { 817 if (bd->queue == q) { 818 atomic_inc(&bd->ref_count); 819 goto found; 820 } 821 } 822 bd = NULL; 823 found: 824 mutex_unlock(&bsg_mutex); 825 return bd; 826 } 827 828 static struct bsg_device *bsg_get_device(struct inode *inode, struct file *file) 829 { 830 struct bsg_device *bd; 831 struct bsg_class_device *bcd; 832 833 /* 834 * find the class device 835 */ 836 mutex_lock(&bsg_mutex); 837 bcd = idr_find(&bsg_minor_idr, iminor(inode)); 838 if (bcd) 839 kref_get(&bcd->ref); 840 mutex_unlock(&bsg_mutex); 841 842 if (!bcd) 843 return ERR_PTR(-ENODEV); 844 845 bd = __bsg_get_device(iminor(inode), bcd->queue); 846 if (bd) 847 return bd; 848 849 bd = bsg_add_device(inode, bcd->queue, file); 850 if (IS_ERR(bd)) 851 kref_put(&bcd->ref, bsg_kref_release_function); 852 853 return bd; 854 } 855 856 static int bsg_open(struct inode *inode, struct file *file) 857 { 858 struct bsg_device *bd; 859 860 lock_kernel(); 861 bd = bsg_get_device(inode, file); 862 unlock_kernel(); 863 864 if (IS_ERR(bd)) 865 return PTR_ERR(bd); 866 867 file->private_data = bd; 868 return 0; 869 } 870 871 static int bsg_release(struct inode *inode, struct file *file) 872 { 873 struct bsg_device *bd = file->private_data; 874 875 file->private_data = NULL; 876 return bsg_put_device(bd); 877 } 878 879 static unsigned int bsg_poll(struct file *file, poll_table *wait) 880 { 881 struct bsg_device *bd = file->private_data; 882 unsigned int mask = 0; 883 884 poll_wait(file, &bd->wq_done, wait); 885 poll_wait(file, &bd->wq_free, wait); 886 887 spin_lock_irq(&bd->lock); 888 if (!list_empty(&bd->done_list)) 889 mask |= POLLIN | POLLRDNORM; 890 if (bd->queued_cmds >= bd->max_queue) 891 mask |= POLLOUT; 892 spin_unlock_irq(&bd->lock); 893 894 return mask; 895 } 896 897 static long bsg_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 898 { 899 struct bsg_device *bd = file->private_data; 900 int __user *uarg = (int __user *) arg; 901 int ret; 902 903 switch (cmd) { 904 /* 905 * our own ioctls 906 */ 907 case SG_GET_COMMAND_Q: 908 return put_user(bd->max_queue, uarg); 909 case SG_SET_COMMAND_Q: { 910 int queue; 911 912 if (get_user(queue, uarg)) 913 return -EFAULT; 914 if (queue < 1) 915 return -EINVAL; 916 917 spin_lock_irq(&bd->lock); 918 bd->max_queue = queue; 919 spin_unlock_irq(&bd->lock); 920 return 0; 921 } 922 923 /* 924 * SCSI/sg ioctls 925 */ 926 case SG_GET_VERSION_NUM: 927 case SCSI_IOCTL_GET_IDLUN: 928 case SCSI_IOCTL_GET_BUS_NUMBER: 929 case SG_SET_TIMEOUT: 930 case SG_GET_TIMEOUT: 931 case SG_GET_RESERVED_SIZE: 932 case SG_SET_RESERVED_SIZE: 933 case SG_EMULATED_HOST: 934 case SCSI_IOCTL_SEND_COMMAND: { 935 void __user *uarg = (void __user *) arg; 936 return scsi_cmd_ioctl(file, bd->queue, NULL, cmd, uarg); 937 } 938 case SG_IO: { 939 struct request *rq; 940 struct bio *bio, *bidi_bio = NULL; 941 struct sg_io_v4 hdr; 942 943 if (copy_from_user(&hdr, uarg, sizeof(hdr))) 944 return -EFAULT; 945 946 rq = bsg_map_hdr(bd, &hdr); 947 if (IS_ERR(rq)) 948 return PTR_ERR(rq); 949 950 bio = rq->bio; 951 if (rq->next_rq) 952 bidi_bio = rq->next_rq->bio; 953 blk_execute_rq(bd->queue, NULL, rq, 0); 954 ret = blk_complete_sgv4_hdr_rq(rq, &hdr, bio, bidi_bio); 955 956 if (copy_to_user(uarg, &hdr, sizeof(hdr))) 957 return -EFAULT; 958 959 return ret; 960 } 961 /* 962 * block device ioctls 963 */ 964 default: 965 #if 0 966 return ioctl_by_bdev(bd->bdev, cmd, arg); 967 #else 968 return -ENOTTY; 969 #endif 970 } 971 } 972 973 static const struct file_operations bsg_fops = { 974 .read = bsg_read, 975 .write = bsg_write, 976 .poll = bsg_poll, 977 .open = bsg_open, 978 .release = bsg_release, 979 .unlocked_ioctl = bsg_ioctl, 980 .owner = THIS_MODULE, 981 }; 982 983 void bsg_unregister_queue(struct request_queue *q) 984 { 985 struct bsg_class_device *bcd = &q->bsg_dev; 986 987 if (!bcd->class_dev) 988 return; 989 990 mutex_lock(&bsg_mutex); 991 idr_remove(&bsg_minor_idr, bcd->minor); 992 sysfs_remove_link(&q->kobj, "bsg"); 993 device_unregister(bcd->class_dev); 994 bcd->class_dev = NULL; 995 kref_put(&bcd->ref, bsg_kref_release_function); 996 mutex_unlock(&bsg_mutex); 997 } 998 EXPORT_SYMBOL_GPL(bsg_unregister_queue); 999 1000 int bsg_register_queue(struct request_queue *q, struct device *parent, 1001 const char *name, void (*release)(struct device *)) 1002 { 1003 struct bsg_class_device *bcd; 1004 dev_t dev; 1005 int ret, minor; 1006 struct device *class_dev = NULL; 1007 const char *devname; 1008 1009 if (name) 1010 devname = name; 1011 else 1012 devname = parent->bus_id; 1013 1014 /* 1015 * we need a proper transport to send commands, not a stacked device 1016 */ 1017 if (!q->request_fn) 1018 return 0; 1019 1020 bcd = &q->bsg_dev; 1021 memset(bcd, 0, sizeof(*bcd)); 1022 1023 mutex_lock(&bsg_mutex); 1024 1025 ret = idr_pre_get(&bsg_minor_idr, GFP_KERNEL); 1026 if (!ret) { 1027 ret = -ENOMEM; 1028 goto unlock; 1029 } 1030 1031 ret = idr_get_new(&bsg_minor_idr, bcd, &minor); 1032 if (ret < 0) 1033 goto unlock; 1034 1035 if (minor >= BSG_MAX_DEVS) { 1036 printk(KERN_ERR "bsg: too many bsg devices\n"); 1037 ret = -EINVAL; 1038 goto remove_idr; 1039 } 1040 1041 bcd->minor = minor; 1042 bcd->queue = q; 1043 bcd->parent = get_device(parent); 1044 bcd->release = release; 1045 kref_init(&bcd->ref); 1046 dev = MKDEV(bsg_major, bcd->minor); 1047 class_dev = device_create(bsg_class, parent, dev, "%s", devname); 1048 if (IS_ERR(class_dev)) { 1049 ret = PTR_ERR(class_dev); 1050 goto put_dev; 1051 } 1052 bcd->class_dev = class_dev; 1053 1054 if (q->kobj.sd) { 1055 ret = sysfs_create_link(&q->kobj, &bcd->class_dev->kobj, "bsg"); 1056 if (ret) 1057 goto unregister_class_dev; 1058 } 1059 1060 mutex_unlock(&bsg_mutex); 1061 return 0; 1062 1063 unregister_class_dev: 1064 device_unregister(class_dev); 1065 put_dev: 1066 put_device(parent); 1067 remove_idr: 1068 idr_remove(&bsg_minor_idr, minor); 1069 unlock: 1070 mutex_unlock(&bsg_mutex); 1071 return ret; 1072 } 1073 EXPORT_SYMBOL_GPL(bsg_register_queue); 1074 1075 static struct cdev bsg_cdev; 1076 1077 static int __init bsg_init(void) 1078 { 1079 int ret, i; 1080 dev_t devid; 1081 1082 bsg_cmd_cachep = kmem_cache_create("bsg_cmd", 1083 sizeof(struct bsg_command), 0, 0, NULL); 1084 if (!bsg_cmd_cachep) { 1085 printk(KERN_ERR "bsg: failed creating slab cache\n"); 1086 return -ENOMEM; 1087 } 1088 1089 for (i = 0; i < BSG_LIST_ARRAY_SIZE; i++) 1090 INIT_HLIST_HEAD(&bsg_device_list[i]); 1091 1092 bsg_class = class_create(THIS_MODULE, "bsg"); 1093 if (IS_ERR(bsg_class)) { 1094 ret = PTR_ERR(bsg_class); 1095 goto destroy_kmemcache; 1096 } 1097 1098 ret = alloc_chrdev_region(&devid, 0, BSG_MAX_DEVS, "bsg"); 1099 if (ret) 1100 goto destroy_bsg_class; 1101 1102 bsg_major = MAJOR(devid); 1103 1104 cdev_init(&bsg_cdev, &bsg_fops); 1105 ret = cdev_add(&bsg_cdev, MKDEV(bsg_major, 0), BSG_MAX_DEVS); 1106 if (ret) 1107 goto unregister_chrdev; 1108 1109 printk(KERN_INFO BSG_DESCRIPTION " version " BSG_VERSION 1110 " loaded (major %d)\n", bsg_major); 1111 return 0; 1112 unregister_chrdev: 1113 unregister_chrdev_region(MKDEV(bsg_major, 0), BSG_MAX_DEVS); 1114 destroy_bsg_class: 1115 class_destroy(bsg_class); 1116 destroy_kmemcache: 1117 kmem_cache_destroy(bsg_cmd_cachep); 1118 return ret; 1119 } 1120 1121 MODULE_AUTHOR("Jens Axboe"); 1122 MODULE_DESCRIPTION(BSG_DESCRIPTION); 1123 MODULE_LICENSE("GPL"); 1124 1125 device_initcall(bsg_init); 1126