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